Nanoparticle curcumin ameliorates experimental colitis via modulation of gut microbiota and induction of regulatory T cells

PubMed Central

Ohno, Masashi; Sugitani, Yoshihiko; Nishino, Kyohei; Inatomi, Osamu; Sugimoto, Mitsushige; Kawahara, Masahiro; Andoh, Akira

2017-01-01

Background and Aims Curcumin is a hydrophobic polyphenol derived from turmeric, a traditional Indian spice. Curcumin exhibits various biological functions, but its clinical application is limited due to its poor absorbability after oral administration. A newly developed nanoparticle curcumin shows improved absorbability in vivo. In this study, we examined the effects of nanoparticle curcumin (named Theracurmin) on experimental colitis in mice. Methods BALB/c mice were fed with 3% dextran sulfate sodium (DSS) in water. Mucosal cytokine expression and lymphocyte subpopulation were analyzed by real-time PCR and flow cytometry, respectively. The profile of the gut microbiota was analyzed by real-time PCR. Results Treatment with nanoparticle curcumin significantly attenuated body weight loss, disease activity index, histological colitis score and significantly improved mucosal permeability. Immunoblot analysis showed that NF-κB activation in colonic epithelial cells was significantly suppressed by treatment with nanoparticle curcumin. Mucosal mRNA expression of inflammatory mediators was significantly suppressed by treatment with nanoparticle curcumin. Treatment with nanoparticle curcumin increased the abundance of butyrate-producing bacteria and fecal butyrate level. This was accompanied by increased expansion of CD4+ Foxp3+ regulatory T cells and CD103+ CD8α− regulatory dendritic cells in the colonic mucosa. Conclusions Treatment with nanoparticle curcumin suppressed the development of DSS-induced colitis potentially via modulation of gut microbial structure. These responses were associated with induction of mucosal immune cells with regulatory properties. Nanoparticle curcumin is one of the promising candidates as a therapeutic option for the treatment of IBD. PMID:28985227

Antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.

PubMed

Ginjupalli, Kishore; Alla, Rama Krishna; Tellapragada, Chaitanya; Gupta, Lokendra; Upadhya Perampalli, Nagaraja

2016-06-01

Conventional spray and the immersion disinfection of irreversible hydrocolloid impression materials may lead to dimensional changes. The purpose of this in vitro study was to investigate the antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles. The antimicrobial activity and properties of 2 commercially available irreversible hydrocolloid impression materials were evaluated after incorporating varying concentrations of silver nanoparticles. Antimicrobial activity was determined using the disk diffusion method. The gel strength, permanent deformation, flow, and gelation time were measured according to American Dental Association specification #18. Analysis of variance was used to identify the significant differences within and across the groups (α=.05). Adding silver nanoparticles to irreversible hydrocolloid impression materials resulted in superior antimicrobial activity without adversely affecting their properties. Adding silver nanoparticles to Zelgan significantly increased the gel strength compared with the control group, except at 5 wt%. However, the gel strength of Tropicalgin was unaffected except at 5 wt%. An increase in the permanent deformation was found with the incorporation of silver nanoparticles in both Zelgan and Tropicalgin. The flow of Zelgan increased with the incorporation of silver nanoparticles, whereas a decrease in the flow of Tropicalgin was observed at 1 wt% and 2 wt%. An increase in the gelation time of both Zelgan and Tropicalgin was observed with the incorporation of silver nanoparticles. Based on this in vitro study, silver nanoparticles can be incorporated into irreversible hydrocolloid impression materials as antimicrobial agents without adversely affecting their properties. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The antihypertensive effect of orally administered nifedipine-loaded nanoparticles in spontaneously hypertensive rats.

PubMed

Kim, Y I; Fluckiger, L; Hoffman, M; Lartaud-Idjouadiene, I; Atkinson, J; Maincent, P

1997-02-01

1. The therapeutic use of nifedipine is limited by the rapidity of the onset of its action and its short biological half-life. In order to produce a form devoid of these disadvantages we made nanoparticles of nifedipine from three different polymers, poly-epsilon-caprolactone (PCL), polylactic and glycolic acid (1:1) copolymers (PLAGA), and Eudragit RL/RS (Eudragit). Nifedipine in polyethylene glycol 400 (PEG) solution was used as a control. 2. The average diameters of the nanoparticles ranged from 0.12 to 0.21 micron; the encapsulation ratio was 82% to 88%. 3. In spontaneously hypertensive rats (SHR), the initial rapid fall in systolic arterial blood pressure following oral administration of nifedipine in PEG solution (from 193 +/- 3 to 102 +/- 2 mmHg) was not seen following administration of the same dose in Eudragit nanoparticles (from 189 +/- 2 to 156 +/- 2 mmHg); with PCL and PLAGA nanoparticles the initial fall in blood pressure was significantly reduced (nadirs PCL 124 +/- 2 and PLAGA 113 +/- 2 mmHg). Ten hours following administration, blood pressure in rats administered the nifedipine/PEG preparation had returned to normal (183 +/- 3 mmHg) whereas that of animals given nifedipine in nanoparticles (PCL 170 +/- 3, PLAGA 168 +/- 2, Eudragit 160 +/- 3 mmHg) was still significantly reduced. 4. All of the nanoparticle dosage forms decreased Cmax and increased Tmax and the mean residence time (MRT) values. Relative bioavailability was significantly increased with Eudragit nanoparticles compared to the nifedipine/PEG solution. 5. There was an inverse linear correlation between the fall in blood pressure and plasma nifedipine concentration with all preparations. 6. The nanoparticle nifedipine preparations represent sustained release forms with increased bioavailability, a less pronounced initial antihypertensive effect and a long-lasting action.

Effect of silver nanoparticles on concentration of silver heavy element and growth indexes in cucumber ( Cucumis sativus L . negeen)

NASA Astrophysics Data System (ADS)

Shams, Gholamabbas; Ranjbar, Morteza; Amiri, Aliasghar

2013-05-01

The tremendous progress on nanoparticle research area has been made significant effects on the economy, society, and the environment. Silver nanoparticle is one of the most important particles in these categories. Silver nanoparticles can be converted to the heavy silver metal in water by oxidation. Moreover, in the high amounts of silver concentration, they will be accumulated in different parts of the plant. However, by changing the morphology of the plant, the production will be harmful for human consumptions. In this study, nano-powders with average 50 nm silver particles are mixed with deionized distilled water in a completely randomized design. Seven treatments with various concentrations of suspension silver nanoparticles were prepared and repeated in four different parts of the plant in a regular program of spraying. Samples were analyzed to study the growth indexes and concentration of silver in different parts of the plant. It was observed that with increasing concentration of silver nanoparticles on cucumber, the growth indexes (except pH fruit), and the concentration of silver heavy metal are increased significantly. The incremental concentration had the linear relationship with correlation coefficient 0.95 and an average of 0.617 PPM by increasing of each unit in one thousand concentration of nanosilver. Although, by increasing concentration of silver nanoparticles as spraying form, the plant morphological characteristics were improved, the concentration of silver heavy metal in various plant organs was increased. These results open a new pathway to consider the effect of nanoparticles on plant's productions for human consumptions.

Enhancing the magnetic anisotropy of maghemite nanoparticles via the surface coordination of molecular complexes

NASA Astrophysics Data System (ADS)

Prado, Yoann; Daffé, Niéli; Michel, Aude; Georgelin, Thomas; Yaacoub, Nader; Grenèche, Jean-Marc; Choueikani, Fadi; Otero, Edwige; Ohresser, Philippe; Arrio, Marie-Anne; Cartier-Dit-Moulin, Christophe; Sainctavit, Philippe; Fleury, Benoit; Dupuis, Vincent; Lisnard, Laurent; Fresnais, Jérôme

2015-12-01

Superparamagnetic nanoparticles are promising objects for data storage or medical applications. In the smallest--and more attractive--systems, the properties are governed by the magnetic anisotropy. Here we report a molecule-based synthetic strategy to enhance this anisotropy in sub-10-nm nanoparticles. It consists of the fabrication of composite materials where anisotropic molecular complexes are coordinated to the surface of the nanoparticles. Reacting 5 nm γ-Fe2O3 nanoparticles with the [CoII(TPMA)Cl2] complex (TPMA: tris(2-pyridylmethyl)amine) leads to the desired composite materials and the characterization of the functionalized nanoparticles evidences the successful coordination--without nanoparticle aggregation and without complex dissociation--of the molecular complexes to the nanoparticles surface. Magnetic measurements indicate the significant enhancement of the anisotropy in the final objects. Indeed, the functionalized nanoparticles show a threefold increase of the blocking temperature and a coercive field increased by one order of magnitude.

Improving nanoparticle diffusion through tumor collagen matrix by photo-thermal gold nanorods

NASA Astrophysics Data System (ADS)

Raeesi, Vahid; Chan, Warren C. W.

2016-06-01

Collagen (I) impairs the targeting of nanoparticles to tumor cells by obstructing their diffusion inside dense tumor interstitial matrix. This potentially makes large nanoparticles (>50 nm) reside near the tumor vessels and thereby compromises their functionality. Here we propose a strategy to locally improve nanoparticle transport inside collagen (I) component of the tumor tissue. We first used heat generating gold nanorods to alter collagen (I) matrix by local temperature elevation. We then explored this impact on the transport of 50 nm and 120 nm inorganic nanoparticles inside collagen (I). We demonstrated an increase in average diffusivity of 50 nm and 120 nm in the denatured collagen (I) by ~14 and ~21 fold, respectively, compared to intact untreated collagen (I) matrix. This study shows how nanoparticle-mediated hyperthermia inside tumor tissue can improve the transport of large nanoparticles through collagen (I) matrix. The ability to increase nanoparticles diffusion inside tumor stroma allows their targeting or other functionalities to take effect, thereby significantly improving cancer therapeutic or diagnostic outcome.Collagen (I) impairs the targeting of nanoparticles to tumor cells by obstructing their diffusion inside dense tumor interstitial matrix. This potentially makes large nanoparticles (>50 nm) reside near the tumor vessels and thereby compromises their functionality. Here we propose a strategy to locally improve nanoparticle transport inside collagen (I) component of the tumor tissue. We first used heat generating gold nanorods to alter collagen (I) matrix by local temperature elevation. We then explored this impact on the transport of 50 nm and 120 nm inorganic nanoparticles inside collagen (I). We demonstrated an increase in average diffusivity of 50 nm and 120 nm in the denatured collagen (I) by ~14 and ~21 fold, respectively, compared to intact untreated collagen (I) matrix. This study shows how nanoparticle-mediated hyperthermia inside tumor tissue can improve the transport of large nanoparticles through collagen (I) matrix. The ability to increase nanoparticles diffusion inside tumor stroma allows their targeting or other functionalities to take effect, thereby significantly improving cancer therapeutic or diagnostic outcome. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08463f

Development of Acyclovir-Loaded Albumin Nanoparticles and Improvement of Acyclovir Permeation Across Human Corneal Epithelial T Cells.

PubMed

Suwannoi, Panita; Chomnawang, Mullika; Sarisuta, Narong; Reichl, Stephan; Müller-Goymann, Christel C

2017-12-01

The aim of the present study was to develop acyclovir (ACV) ocular drug delivery systems of bovine serum albumin (BSA) nanoparticles as well as to assess their in vitro transcorneal permeation across human corneal epithelial (HCE-T) cell multilayers. The ACV-loaded BSA nanoparticles were prepared by desolvation method along with physicochemical characterization, cytotoxicity, as well as in vitro transcorneal permeation studies across HCE-T cell multilayers. The nanoparticles appeared to be spherical in shape and nearly uniform in size of about 200 nm. The size of nanoparticles became smaller with decreasing BSA concentration, while the ratios of water to ethanol seemed not to affect the size. Increasing the amount of ethanol in desolvation process led to significant reduction of drug entrapment of nanoparticles with smaller size and more uniformity. The ACV-loaded BSA nanoparticles prepared were shown to have no cytotoxic effect on HCE-T cells used in permeation studies. The in vitro transcorneal permeation results revealed that ACV could permeate through the HCE-T cell multilayers significantly higher from BSA nanoparticles than from aqueous ACV solutions. The ACV-loaded BSA nanoparticles could be prepared by desolvation method without glutaraldehyde in the formulation. ACV could increasingly permeate through the multilayers of HCE-T cells from the ACV-loaded BSA nanoparticles. Therefore, the ACV-loaded BSA nanoparticles could be a highly potential ocular drug delivery system.

Experimental investigation of the influence of nanoparticles on water-based mud

NASA Astrophysics Data System (ADS)

Dhiman, Paritosh; Cheng, Yaoze; Zhang, Yin; Patil, Shirish

2018-03-01

This study has investigated the influence of nanoparticles including nanoparticle concentration, size, and type on water-based mud (WBM) properties including rheology, filtration, and lubricity through experimental tests, while the influence of temperature and aging on these properties have been investigated. It has been found that adding SiO2 nanoparticles increase the plastic viscosity and decrease the yield points and gel strengths with the increase of nanoparticle concentration. At fixed 0.5 wt%, the plastic viscosity decreases with the increase of TiO2 nanoparticle size, but the influence of TiO2 nanoparticle size on yield points and gel strengths is not monotonous. In general, adding negative charged SiO2 nanoparticles reduce the yield points and gel strengths, while adding positively charged TiO2, Al2O3, and Fe3O4 nanoparticles increase yield points and gel strengths. Adding lower concentrations (< 0.05 wt%) of SiO2 nanoparticles improved mud filtration and lubricity properties, but higher concentrations are adverse to these properties and adding 0.5 wt% TiO2, Al2O3 and Fe3O4 nanoparticles impaired these properties. Besides, it is found that there is no consistent influence of aging on mud properties and adding nanoparticles cannot improve aging resistance of mud. Although adding nanoparticles can significantly affect WBM properties, their influences are not consistency, depending on the integrated impact of the nanoparticle properties, such as surface electrical property, specific surface area, concentration, and size.

Acid-sensitive sheddable PEGylated, mannose-modified nanoparticles increase the delivery of betamethasone to chronic inflammation sites in a mouse model

PubMed Central

O’Mary, Hannah L.; Aldayel, Abdulaziz M.; Valdes, Solange A.; Naguib, Youssef W.; Li, Xu; Salvady, Karun; Cui, Zhengrong

2017-01-01

Inflammation is implicated in a host of chronic illnesses. Within these inflamed tissues, the pH of the microenvironment is decreased and immune cells, particularly macrophages, infiltrate the area. Additionally, the vascular integrity of these sites is altered with increased fenestrations between endothelial cells. These distinctive properties may be exploited to enhance targeted delivery of anti-inflammatory therapies. Using a mouse model of chronic inflammation, we previously showed that acid-sensitive sheddable PEGylation increases the distribution and retention of nanoparticles in chronic inflammation sites. Here we demonstrated that surface modification of the acid-sensitive sheddable PEGylated nanoparticles with mannose, a ligand to mannose receptors present in chronic inflammation sites, significantly increases the targeted delivery of the nanoparticles to these areas. Furthermore, we showed that the acid-sensitive sheddable PEGylated, mannose-modified nanoparticles are able to significantly increase the delivery of betamethasone-21-acetate (BA), a model anti-inflammatory compound, to chronic inflammation sites as compared to free BA. These results highlight the ability to engineer formulations to target chronic inflammation sites by exploiting the microenvironment of these regions. PMID:28463518

Can visible light impact litter decomposition under pollution of ZnO nanoparticles?

PubMed

Du, Jingjing; Zhang, Yuyan; Liu, Lina; Qv, Mingxiang; Lv, Yanna; Yin, Yifei; Zhou, Yinfei; Cui, Minghui; Zhu, Yanfeng; Zhang, Hongzhong

2017-11-01

ZnO nanoparticles is one of the most used materials in a wide range including antibacterial coating, electronic device, and personal care products. With the development of nanotechnology, ecotoxicology of ZnO nanoparticles has been received increasing attention. To assess the phototoxicity of ZnO nanoparticles in aquatic ecosystem, microcosm experiments were conducted on Populus nigra L. leaf litter decomposition under combined effect of ZnO nanoparticles and visible light radiation. Litter decomposition rate, pH value, extracellular enzyme activity, as well as the relative contributions of fungal community to litter decomposition were studied. Results showed that long-term exposure to ZnO nanoparticles and visible light led to a significant decrease in litter decomposition rate (0.26 m -1 vs 0.45 m -1 ), and visible light would increase the inhibitory effect (0.24 m -1 ), which caused significant decrease in pH value of litter cultures, fungal sporulation rate, as well as most extracellular enzyme activities. The phototoxicity of ZnO nanoparticles also showed impacts on fungal community composition, especially on the genus of Varicosporium, whose abundance was significantly and positively related to decomposition rate. In conclusion, our study provides the evidence for negatively effects of ZnO NPs photocatalysis on ecological process of litter decomposition and highlights the contribution of visible light radiation to nanoparticles toxicity in freshwater ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Herceptin conjugated PLGA-PHis-PEG pH sensitive nanoparticles for targeted and controlled drug delivery.

PubMed

Zhou, Zilan; Badkas, Apurva; Stevenson, Max; Lee, Joo-Youp; Leung, Yuet-Kin

2015-06-20

A dual functional nano-scaled drug carrier, comprising of a targeting ligand and pH sensitivity, has been made in order to increase the specificity and efficacy of the drug delivery system. The nanoparticles are made of a tri-block copolymer, poly(d,l lactide-co-glycolide) (PLGA)-b-poly(l-histidine) (PHis)-b-polyethylene glycol (PEG), via nano-precipitation. To provide the nanoparticle feature of endolysosomal escape and pH sensitivity, poly(l-histidine) was chosen as a proton sponge polymer. Herceptin, which specifically binds to HER2 antigen, was conjugated to the nanoparticles through click chemistry. The nanoparticles were characterized via dynamic light scattering (DLS) and transmission electron microscopy (TEM). Both methods showed the sizes of about 100nm with a uniform size distribution. The pH sensitivity was assessed by drug releases and size changes at different pH conditions. As pH decreased from 7.4 to 5.2, the drug release rate accelerated and the size significantly increased. During in vitro tests against human breast cancer cell lines, MCF-7 and SK-BR-3 showed significantly increased uptake for Herceptin-conjugated nanoparticles, as compared to non-targeted nanoparticles. Herceptin-conjugated pH-sensitive nanoparticles showed the highest therapeutic effect, and thus validated the efficacy of a combined approach of pH sensitivity and active targeting. Copyright © 2015 Elsevier B.V. All rights reserved.

Implications of SPION and NBT nanoparticles upon in-vitro and in-situ biodegradation of LDPE film.

PubMed

Kapri, Anil; Zaidi, M G H; Goel, Reeta

2010-06-01

Comparative influence of two nanoparticles viz. superparamagnetic iron oxide nanoparticles (SPION) and nanobarium titanate (NBT) was studied upon the in-vitro and in-situ low-density polyethylene (LDPE) biodegradation efficiency of a potential polymer-degrading microbial consortium. Supplementation of 0.01% concentration (w/v) of the nanoparticles in minimal broth significantly increased the bacterial growth, along with early onset of the exponential phase. Under in-vitro conditions, lambda-max shifts were quicker with nanoparticles and Fourier transform infrared spectroscopy (FTIR) illustrated significant changes in CH/CH2 vibrations, along with introduction of hydroxyl residues in the polymer backbone. Further, simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA) reported multiple-step decomposition of LDPE degraded in the presence of nanoparticles. These findings were supported by scanning electron micrographs (SEM) which revealed greater dissolution of film surface in the presence of nanoparticles. Furthermore, progressive degradation of the film was greatly enhanced when it was incubated under soil conditions for 3 months with the nanoparticles. The study highlights the significance of bacteria-nanoparticle interactions which can dramatically influence key metabolic processes like biodegradation. The authors also propose the exploration of nanoparticles to influence various other microbial processes for commercial viabilities.

Chitosan nanoparticles-trypsin interactions: Bio-physicochemical and molecular dynamics simulation studies.

PubMed

Salar, Safoura; Mehrnejad, Faramarz; Sajedi, Reza H; Arough, Javad Mohammadnejad

2017-10-01

Herein, we investigated the effect of the chitosan nanoparticles (CsNP) on the structure, dynamics, and activity of trypsin. The enzyme activity in complex with the nanoparticles slightly increased, which represents the interactions between the nanoparticles and the enzyme. The kinetic parameters of the enzyme, K m and k cat , increased after adding the nanoparticles, resulting in a slight increase in the catalytic efficiency (k cat /K m ). However, the effect of the nanoparticles on the kinetic stability of trypsin has not exhibited significant variations. Fluorescence spectroscopy did not show remarkable changes in the trypsin conformation in the presence of the nanoparticles. The circular dichroism (CD) spectroscopy results also revealed the secondary structure of trypsin attached to the nanoparticles slightly changed. Furthermore, we used molecular dynamics (MD) simulation to find more information about the interaction mechanisms between the nanoparticles and trypsin. The root mean square deviation (RMSD) of Cα atoms results have shown that in the presence of the nanoparticles, trypsin was stable. The simulation and the calculation of the binding free energy demonstrate that the nonpolar interactions are the most important forces for the formation of stable nanoparticle-trypsin complex. This study has explicitly elucidated that the nanoparticles have not considerable effect on the trypsin. Copyright © 2017. Published by Elsevier B.V.

Superparamagnetic iron oxide nanoparticles: promises for diagnosis and treatment of cancer

PubMed Central

Laurent, Sophie; Mahmoudi, Morteza

2011-01-01

During the last decade, significant scientific research efforts have led to a significant growth in understanding of cancer at the genetic, molecular, and cellular levels providing great opportunities for diagnosis and treatment of cancer diseases. The hopes for fast cancer diagnosis and treatment were significantly increased by the entrance of nanoparticles to the medical sciences. Nanoparticles are attractive due to their unique opportunities together with negligible side effects not only in cancer therapy but also in the treatment of other ailments. Among all types of nanoparticles, surface-engineered superparamagnetic iron oxide nanoparticles (SPIONs) have been attracted a great attention for cancer therapy applications. This review covers the recent advances in the development of SPIONs together with their opportunities and challenges, as theranosis agents, in cancer treatment. PMID:22199999

Peptide conjugated magnetic nanoparticles for magnetically mediated energy delivery to lung cancer cells.

PubMed

Hauser, Anastasia K; Anderson, Kimberly W; Hilt, J Zach

2016-07-01

In the present study, we examine the effects of internalized peptide-conjugated iron oxide nanoparticles and their ability to locally convert alternating magnetic field (AMF) energy into other forms of energy (e.g., heat and rotational work). Dextran-coated iron oxide nanoparticles were functionalized with a cell penetrating peptide and after internalization by A549 and H358 cells were activated by an AMF. TAT-functionalized nanoparticles and AMF exposure increased reactive oxygen species generation compared with the nanoparticle system alone. The TAT-functionalized nanoparticles induced lysosomal membrane permeability and mitochondrial membrane depolarization, but these effects were not further enhanced by AMF treatment. Although not statistically significant, there are trends suggesting an increase in apoptosis via the Caspase 3/7 pathways when cells are exposed to TAT-functionalized nanoparticles combined with AMF. Our results indicate that internalized TAT-functionalized iron oxide nanoparticles activated by an AMF elicit cellular responses without a measurable temperature rise.

Oral Delivery of DMAB-Modified Docetaxel-Loaded PLGA-TPGS Nanoparticles for Cancer Chemotherapy

NASA Astrophysics Data System (ADS)

Chen, Hongbo; Zheng, Yi; Tian, Ge; Tian, Yan; Zeng, Xiaowei; Liu, Gan; Liu, Kexin; Li, Lei; Li, Zhen; Mei, Lin; Huang, Laiqiang

2011-12-01

Three types of nanoparticle formulation from biodegradable PLGA-TPGS random copolymer were developed in this research for oral administration of anticancer drugs, which include DMAB-modified PLGA nanoparticles, unmodified PLGA-TPGS nanoparticles and DMAB-modified PLGA-TPGS nanoparticles. Firstly, the PLGA-TPGS random copolymer was synthesized and characterized. DMAB was used to increase retention time at the cell surface, thus increasing the chances of particle uptake and improving oral drug bioavailability. Nanoparticles were found to be of spherical shape with an average particle diameter of around 250 nm. The surface charge of PLGA-TPGS nanoparticles was changed to positive after DMAB modification. The results also showed that the DMAB-modified PLGA-TPGS nanoparticles have significantly higher level of the cellular uptake than that of DMAB-modified PLGA nanoparticles and unmodified PLGA-TPGS nanoparticles. In vitro, cytotoxicity experiment showed advantages of the DMAB-modified PLGA-TPGS nanoparticle formulation over commercial Taxotere® in terms of cytotoxicity against MCF-7 cells. In conclusion, oral chemotherapy by DMAB-modified PLGA-TPGS nanoparticle formulation is an attractive and promising treatment option for patients.

Reinforcement of a PMMA resin for interim fixed prostheses with silica nanoparticles.

PubMed

Topouzi, Marianthi; Kontonasaki, Eleana; Bikiaris, Dimitrios; Papadopoulou, Lambrini; Paraskevopoulos, Konstantinos M; Koidis, Petros

2017-05-01

Fractures in long span provisional/interim restorations are a common complication. Adequate fracture toughness is necessary to resist occlusal forces and crack propagation, so these restorations should be constructed with materials of improved mechanical properties. The aim of this study was to investigate the possible reinforcement of neat silica nanoparticles and trietoxyvinylsilane-modified silica nanoparticles in a PMMA resin for fixed interim restorations. Composite PMMA-Silica nanoparticles powders were mixed with PMMA liquid and compact bar shaped specimens were fabricated according to the British standard BS EN ISO 127337:2005. The single-edge notched method was used to evaluate fracture toughness (three-point bending test), while the dynamic thermomechanical properties (Storage Modulus, Loss Modulus, tanδ) of a series of nanocomposites with different amounts of nanoparticles (0.25%, 0.50%, 0.75%, 1% w.t.) were evaluated. Statistical analysis was performed and the statistically significant level was set to p<0.05. The fracture toughness of all experimental composites was remarkably higher compared to control. There was a tendency to decrease of fracture toughness, by increasing the concentration of the filler. No statistically significant differences were detected among the modified/unmodified silica nanoparticles. Dynamic mechanical properties were also affected. By increasing the silica nanoparticles content an increase in Storage Modulus was recorded, while Glass Transition Temperature was shifted at higher temperatures. Under the limitations of this in-vitro study, it can be suggested that both neat silica nanoparticles and trietoxyvinylsilane-modified silica nanoparticles, especially at low concentrations, may enhance the overall performance of fixed interim prostheses, as can effectively increase the fracture toughness, the elastic modulus and the Glass Transition Temperature of PMMA resins used in fixed provisional restorations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of oleic acid surface coating on the properties of nickel ferrite nanoparticles/PLA composites.

PubMed

Yin, Hong; Chow, Gan-Moog

2009-11-01

Nickel ferrite nanoparticles with or without oleic acid surface coating were mixed with poly(D,L-lactide) (PLA) by double emulsion method. If the nanoparticles were prepared without oleic acid coating, they adsorbed on the PLA surface. If the nanoparticles were coated with oleic acid, they could be readily encapsulated within the PLA microspheres. A slight depression in glass transition temperature was found in all composites and it could be related to the interfacial energies between nanoparticles and PLA. Optimum mixed composite was achieved by reducing interfacial energy. However, loading capacity was limited in this composite. Increasing the amount of nickel ferrite nanoparticles was not useful to increase loading capacity. Cytotoxicity of the composite decreased significantly when nickel ferrite nanoparticles were effectively encapsulated in PLA microspheres. (c) 2008 Wiley Periodicals, Inc.

Dextran and Polymer Polyethylene Glycol (PEG) Coating Reduce Both 5 and 30 nm Iron Oxide Nanoparticle Cytotoxicity in 2D and 3D Cell Culture

PubMed Central

Yu, Miao; Huang, Shaohui; Yu, Kevin Jun; Clyne, Alisa Morss

2012-01-01

Superparamagnetic iron oxide nanoparticles are widely used in biomedical applications, yet questions remain regarding the effect of nanoparticle size and coating on nanoparticle cytotoxicity. In this study, porcine aortic endothelial cells were exposed to 5 and 30 nm diameter iron oxide nanoparticles coated with either the polysaccharide, dextran, or the polymer polyethylene glycol (PEG). Nanoparticle uptake, cytotoxicity, reactive oxygen species (ROS) formation, and cell morphology changes were measured. Endothelial cells took up nanoparticles of all sizes and coatings in a dose dependent manner, and intracellular nanoparticles remained clustered in cytoplasmic vacuoles. Bare nanoparticles in both sizes induced a more than 6 fold increase in cell death at the highest concentration (0.5 mg/mL) and led to significant cell elongation, whereas cell viability and morphology remained constant with coated nanoparticles. While bare 30 nm nanoparticles induced significant ROS formation, neither 5 nm nanoparticles (bare or coated) nor 30 nm coated nanoparticles changed ROS levels. Furthermore, nanoparticles were more toxic at lower concentrations when cells were cultured within 3D gels. These results indicate that both dextran and PEG coatings reduce nanoparticle cytotoxicity, however different mechanisms may be important for different size nanoparticles. PMID:22754315

Enhancing the magnetic anisotropy of maghemite nanoparticles via the surface coordination of molecular complexes

PubMed Central

Prado, Yoann; Daffé, Niéli; Michel, Aude; Georgelin, Thomas; Yaacoub, Nader; Grenèche, Jean-Marc; Choueikani, Fadi; Otero, Edwige; Ohresser, Philippe; Arrio, Marie-Anne; Cartier-dit-Moulin, Christophe; Sainctavit, Philippe; Fleury, Benoit; Dupuis, Vincent; Lisnard, Laurent; Fresnais, Jérôme

2015-01-01

Superparamagnetic nanoparticles are promising objects for data storage or medical applications. In the smallest—and more attractive—systems, the properties are governed by the magnetic anisotropy. Here we report a molecule-based synthetic strategy to enhance this anisotropy in sub-10-nm nanoparticles. It consists of the fabrication of composite materials where anisotropic molecular complexes are coordinated to the surface of the nanoparticles. Reacting 5 nm γ-Fe2O3 nanoparticles with the [CoII(TPMA)Cl2] complex (TPMA: tris(2-pyridylmethyl)amine) leads to the desired composite materials and the characterization of the functionalized nanoparticles evidences the successful coordination—without nanoparticle aggregation and without complex dissociation—of the molecular complexes to the nanoparticles surface. Magnetic measurements indicate the significant enhancement of the anisotropy in the final objects. Indeed, the functionalized nanoparticles show a threefold increase of the blocking temperature and a coercive field increased by one order of magnitude. PMID:26634987

Synthesis of NiAu alloy and core-shell nanoparticles in water-in-oil microemulsions

NASA Astrophysics Data System (ADS)

Chiu, Hsin-Kai; Chiang, I.-Chen; Chen, Dong-Hwang

2009-07-01

NiAu alloy nanoparticles with various Ni/Au molar ratios were synthesized by the hydrazine reduction of nickel chloride and hydrogen tetrachloroaurate in the microemulsion system. They had a face-centered cubic structure and a mean diameter of 6-13 nm, decreasing with increasing Au content. As Au nanoparticles did, they showed a characteristic absorption peak at about 520 nm but the intensity decreased with increasing Ni content. Also, they were nearly superparamagnetic, although the magnetization decreased significantly with increasing Au content. Under an external magnetic field, they could be self-organized into the parallel lines. In addition, the core-shell nanoparticles, Ni3Au1@Au, were prepared by the Au coating on the surface of Ni3Au1 alloy nanoparticles. By increasing the hydrogen tetrachloroaurate concentration for Au coating, the thickness of Au shells could be raised and led to an enhanced and red-shifted surface plasmon absorption.

Antibacterial, physical and mechanical properties of flowable resin composites containing zinc oxide nanoparticles.

PubMed

Tavassoli Hojati, Sara; Alaghemand, Homayoon; Hamze, Faeze; Ahmadian Babaki, Fateme; Rajab-Nia, Ramazan; Rezvani, Mohammad Bagher; Kaviani, Mehrnoosh; Atai, Mohammad

2013-05-01

The aim of this study is evaluating the antibacterial activity of resin composites containing ZnO nanoparticles against Streptococcus mutans and examining their physical and mechanical properties. The properties of flowable resin composites containing 0-5wt.% nano-ZnO are investigated using different tests: Although the agar diffusion test reveals no significant difference between the groups, the direct contact test demonstrates that by increasing the nanoparticle content, the bacterial growth is significantly diminished (p<0.05). In the aging test, however, the antibacterial properties reduce significantly (p<0.05). The flexural strength and compressive modulus remains unchanged by incorporation of nanoparticles (p>0.05) while the compressive strength and flexural modulus significantly increase (p<0.05). The ZnO containing resins show significantly lower depth of cure (p<0.05), and higher bond strength (p<0.05). There is no significant difference between the degrees of conversion, measured by FTIR technique, of the groups (p>0.05). Production of a dental resin composite with antibacterial activity without significant sacrificing effect on the mechanical properties is desirable in dental material science. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Delivery of enteric neural progenitors with 5-HT4 agonist-loaded nanoparticles and thermosensitive hydrogel enhances cell proliferation and differentiation following transplantation in vivo

PubMed Central

Graham, Hannah K.; Nagy, Nandor; Belkind-Gerson, Jaime; Mattheolabakis, George; Amiji, Mansoor M.; Goldstein, Allan M.

2016-01-01

Cell therapy offers an innovative approach for treating enteric neuropathies. Postnatal gut-derived enteric neural stem/progenitor cells (ENSCs) represent a potential autologous source, but have a limited capacity for proliferation and neuronal differentiation. Since serotonin (5-HT) promotes enteric neuronal growth during embryonic development, we hypothesized that serotonin receptor agonism would augment growth of neurons from transplanted ENSCs. Postnatal ENSCs were isolated from 2-4 week-old mouse colon and cultured with 5-HT4 receptor agonist (RS67506)-loaded liposomal nanoparticles. ENSCs were co-cultured with mouse colon explants in the presence of RS67506-loaded (n=3) or empty nanoparticles (n=3). ENSCs were also transplanted into mouse rectum in vivo with RS67506-loaded (n=8) or blank nanoparticles (n=4) confined in a thermosensitive hydrogel, Pluronic F-127. Neuronal density and proliferation were analyzed immunohistochemically. Cultured ENSCs gave rise to significantly more neurons in the presence of RS67506-loaded nanoparticles. Similarly, colon explants had significantly increased neuronal density when RS67506-loaded nanoparticles were present. Finally, following in vivo cell delivery, co-transplantation of ENSCs with 5-HT4 receptor agonist-loaded nanoparticles led to significantly increased neuronal density and proliferation. We conclude that optimization of postnatal ENSCs can support their use in cell-based therapies for neurointestinal diseases. PMID:26922325

Folate-mediated mitochondrial targeting with doxorubicin-polyrotaxane nanoparticles overcomes multidrug resistance

PubMed Central

Yan, Fengjiao; Sun, Mingna; Du, Lingran; Peng, Wei; Li, Qiuli; Feng, Yinghong; Zhou, Yi

2015-01-01

Resistance to treatment with anticancer drugs is a significant obstacle and a fundamental cause of therapeutic failure in cancer therapy. Functional doxorubicin (DOX) nanoparticles for targeted delivery of the classical cytotoxic anticancer drug DOX to tumor cells, using folate-terminated polyrotaxanes along with dequalinium, have been developed and proven to overcome this resistance due to specific molecular features, including a size of approximately 101 nm, a zeta potential of 3.25 mV and drug-loading content of 18%. Compared with free DOX, DOX hydrochloride, DOX nanoparticles, and targeted DOX nanoparticles, the functional DOX nanoparticles exhibited the strongest anticancer efficacy in vitro and in the drug-resistant MCF-7/ Adr (DOX) xenograft tumor model. More specifically, the nanoparticles significantly increased the intracellular uptake of DOX, selectively accumulating in mitochondria and the endoplasmic reticulum after treatment, with release of cytochrome C as a result. Furthermore, the caspase-9 and caspase-3 cascade was activated by the functional DOX nanoparticles through upregulation of the pro-apoptotic proteins Bax and Bid and suppression of the antiapoptotic protein Bcl-2, thereby enhancing apoptosis by acting on the mitochondrial signaling pathways. In conclusion, functional DOX nanoparticles may provide a strategy for increasing the solubility of DOX and overcoming multidrug-resistant cancers. PMID:25605018

Improved insulin loading in poly(lactic-co-glycolic) acid (PLGA) nanoparticles upon self-assembly with lipids.

PubMed

García-Díaz, María; Foged, Camilla; Nielsen, Hanne Mørck

2015-03-30

Polymeric nanoparticles are widely investigated as drug delivery systems for oral administration. However, the hydrophobic nature of many polymers hampers effective loading of the particles with hydrophilic macromolecules such as insulin. Thus, the aim of this work was to improve the loading of insulin into poly(lactic-co-glycolic) acid (PLGA) nanoparticles by pre-assembly with amphiphilic lipids. Insulin was complexed with soybean phosphatidylcholine or sodium caprate by self-assembly and subsequently loaded into PLGA nanoparticles by using the double emulsion-solvent evaporation technique. The nanoparticles were characterized in terms of size, zeta potential, insulin encapsulation efficiency and loading capacity. Upon pre-assembly with lipids, there was an increased distribution of insulin into the organic phase of the emulsion, eventually resulting in significantly enhanced encapsulation efficiencies (90% as compared to 24% in the absence of lipids). Importantly, the insulin loading capacity was increased up to 20% by using the lipid-insulin complexes. The results further showed that a main fraction of the lipid was incorporated into the nanoparticles and remained associated to the polymer during release studies in buffers, whereas insulin was released in a non-complexed form as a burst of approximately 80% of the loaded insulin. In conclusion, the protein load in PLGA nanoparticles can be significantly increased by employing self-assembled protein-lipid complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

Developmental toxicity and DNA damaging properties of silver nanoparticles in the catfish (Clarias gariepinus).

PubMed

Sayed, Alaa El-Din H; Soliman, Hamdy A M

2017-10-01

Although, silver nanoparticles (AgNPs) are used in many different products, little information is known about their toxicity in tropical fish embryos. Therefore, this study evaluated the developmental toxicity of waterborne silver nanoparticles in embryos of Clarias gariepinus. Embryos were treated with (0, 25, 50, 75ng/L silver nanoparticles) in water up to 144h postfertilization stage (PFS). Results revealed various morphological malformations including notochord curvature and edema. The mortality rate, malformations, and DNA fragmentation in embryos exposed to silver nanoparticles increased in a dose- and embryonic stage-dependent manner. The total antioxidant capacity and the activity of catalase in embryos exposed to 25ng/L silver nanoparticles were decreased significantly while the total antioxidant capacity and the activity of catalase were insignificantly increased with increasing concentrations in the embryos from 24 to 144 h-PFS exposed to 50 and 75ng/L silver nanoparticles. Lipid peroxidation values showed fluctuations with doses of silver nanoparticles. Histopathological lesions including severely distorted and wrinkled notochord were observed. The current data propose that the toxicity of silver nanoparticles in C. gariepinus embryos is caused by oxidative stress and genotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of ZnO nanoparticle-coated packaging film on pork meat quality during cold storage.

PubMed

Suo, Biao; Li, Huarong; Wang, Yuexia; Li, Zhen; Pan, Zhili; Ai, Zhilu

2017-05-01

There has been limited research on the use of ZnO nanoparticle-coated film for the quality preservation of pork meat under low temperature. In the present study, ZnO nanoparticles were mixed with sodium carboxymethyl cellulose (CMC-Na) to form a nanocomposite film, to investigate the effect of ZnO nanoparticle-coated film on pork meat quality and the growth of bacteria during storage under low temperature. When ZnO nanoparticle-coated film was used as the packaging material for pork meat for 14 days of cold storage at 4 °C, the results demonstrated a significant effect on restricting the increases in total volatile basic nitrogen and pH levels, limiting the decreases of lightness (increased L* value) and redness (increased a* value), and maintaining the water-holding capacity compared to the control pork samples (P < 0.05). The present study also discovered that the ZnO nanoparticle-coated film restrained the increase in total plate count (TPC). When Staphylococcus aureus was used as the representative strain, scanning electron microscopy revealed that ZnO nanoparticles increased the occurrence of cell membrane rupture under cold conditions. ZnO nanoparticle-coated film helps retain the quality of pork meat during cold storage by increasing the occurrence of microorganism injury. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Protective role of biosynthesized silver nanoparticles against early blight disease in Solanum lycopersicum.

PubMed

Kumari, Madhuree; Pandey, Shipra; Bhattacharya, Arpita; Mishra, Aradhana; Nautiyal, C S

2017-12-01

Tomato suffers a huge loss every year because of early blight disease. This study focuses on efficient inhibition of Alternaria solani, the causative agent of early blight disease in tomato in vitro and in vivo. Foliar spray of 5 μg/mL of biosynthesized silver nanoparticles in A. solani infected plants resulted in significant increase of 32.58% in fresh weight and 23.52% in total chlorophyll content of tomato as compared to A. solani infected plants. A decrease of 48.57, 30, 39.59 and 28.57% was observed in fungal spore count, lipid peroxidation, proline content and superoxide dismutase respectively in infected tomato plants after treatment with synthesized silver nanoparticles as compared to A. solani infected plants. No significant variation in terms of soil pH, cultured population, carbon source utilization pattern and soil enzymes including dehydrogenase, urease, protenase and β-glucosidase was observed after foliar spray of nanoparticles. It was revealed that direct killing of pathogens, increased photosynthetic efficiencies, increased plant resistance and decrease in stress parameters and stress enzymes are the mechanisms employed by plants and nanoparticles simultaneously to combat the biotic stress. Biosynthesized silver nanoparticles bear the potential to revolutionize plant disease management, though the molecular aspects of increased resistance must be looked upon. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Dexamethasone acetate encapsulation into Trojan particles.

PubMed

Gómez-Gaete, Carolina; Fattal, Elias; Silva, Lídia; Besnard, Madeleine; Tsapis, Nicolas

2008-05-22

We have combined the therapeutic potential of nanoparticles systems with the ease of manipulation of microparticles by developing a hybrid vector named Trojan particles. We aim to use this new delivery vehicle for intravitreal administration of dexamethasone. Initialy, dexamethasone acetate (DXA) encapsulation into biodegradable poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles was optimized. Then, Trojan particles were formulated by spray drying 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC), hyaluronic acid (HA) and different concentrations of nanoparticle suspensions. The effect of nanoparticles concentration on Trojan particle physical characteristics was investigated as well as the effect of the spray drying process on nanoparticles size. Finally, DXA in vitro release from nanoparticles and Trojan particles was evaluated under sink condition. SEM and confocal microscopy show that most of Trojan particles are spherical, hollow and possess an irregular surface due to the presence of nanoparticles. Neither Trojan particle tap density nor size distribution are significantly modified as a function of nanoparticles concentration. The mean nanoparticles size increase significantly after spray drying. Finally, the in vitro release of DXA shows that the excipient matrix provides protection to encapsulated nanoparticles by slowing drug release.

Determination of zinc oxide nanoparticles toxicity in root growth in wheat (Triticum aestivum L.) seedlings.

PubMed

Prakash, Meppaloor G; Chung, Ill Min

2016-09-01

The effect of zinc oxide nanoparticles (ZnONPs) was studied in wheat (Triticum aestivum L.) seedlings under in vitro exposure conditions. To avoid precipitation of nanoparticles, the seedlings were grown in half strength semisolid Murashige and Skoog medium containing 0, 50, 100, 200, 400 and 500 mg L(-1) of ZnONPs. Analysis of zinc (Zn) content showed significant increase in roots. In vivo detection using fluorescent probe Zynpyr-1 indicated accumulation of Zn in primary and lateral root tips. All concentrations of ZnONPs significantly reduced root growth. However, significant decrease in shoot growth was observed only after exposure to 400 and 500 mg L(-1) of ZnONPs. The reactive oxygen species and lipid peroxidation levels significantly increased in roots. Significant increase in cell-wall bound peroxidase activity was observed after exposure to 500 mg L(-1) of ZnONPs. Histochemical staining with phloroglucinol-HCl showed lignification of root cells upon exposure to 500 mg L(-1) of ZnONPs. Treatment with propidium iodide indicated loss of cell viability in root tips of wheat seedlings. These results suggest that redox imbalances, lignification and cell death has resulted in reduction of root growth in wheat seedlings exposed to ZnONPs nanoparticles.

Protective effect of maghemite nanoparticles on ultraviolet-induced photo-damage in human skin fibroblasts

NASA Astrophysics Data System (ADS)

Lee, Kwon-Jai; An, Jeung-Hee; Shin, Jae-Soo; Kim, Dong-Hee; Kim, Changman; Ozaki, Hajime; Koh, Jae-Gui

2007-11-01

This study examined the optical properties of an oxidized form of maghemite (γ-Fe2O3) nanoparticles and their protective effects against the photoaging of human skin fibroblasts irradiated with ultraviolet (UV) light. Nanoparticles with diameters ranging from 8.7 to 12 nm were prepared using a chemical co-precipitation method. The nanoparticles were coated with two surfactants to obtain a water-based product. The onset of the absorption of the γ-Fe2O3 nanoparticles in the UV-visible absorption spectra increased with increasing particle size. The γ-Fe2O3 nanoparticles significantly inhibited the production of matrix metalloproteinase-1 in human skin fibroblast HS 68 cells by 60% compared with the UV-irradiated control. These results suggest that γ-Fe2O3 nanoparticles have photoprotective properties, and have potential use as an agent against photoaging.

The antihypertensive effect of orally administered nifedipine-loaded nanoparticles in spontaneously hypertensive rats

PubMed Central

Il Kim, Young; Fluckiger, Laurence; Hoffman, Maurice; Lartaud-Idjouadiene, Isabelle; Atkinson, Jeffrey; Maincent, Philippe

1997-01-01

The therapeutic use of nifedipine is limited by the rapidity of the onset of its action and its short biological half-life. In order to produce a form devoid of these disadvantages we made nanoparticles of nifedipine from three different polymers, poly-ε-caprolactone (PCL), polylactic and glycolic acid (1 : 1) copolymers (PLAGA), and Eudragit RL/RS (Eudragit). Nifedipine in polyethylene glycol 400 (PEG) solution was used as a control.The average diameters of the nanoparticles ranged from 0.12 to 0.21 μm; the encapsulation ratio was 82% to 88%.In spontaneously hypertensive rats (SHR), the initial rapid fall in systolic arterial blood pressure following oral administration of nifedipine in PEG solution (from 193±3 to 102±2 mmHg) was not seen following administration of the same dose in Eudragit nanoparticles (from 189±2 to 156±2 mmHg); with PCL and PLAGA nanoparticles the initial fall in blood pressure was significantly reduced (nadirs PCL 124±2 and PLAGA 113±2 mmHg). Ten hours following administration, blood pressure in rats administered the nifedipine/PEG preparation had returned to normal (183±3 mmHg) whereas that of animals given nifedipine in nanoparticles (PCL 170±3, PLAGA 168±2, Eudragit 160±3 mmHg) was still significantly reduced.All of the nanoparticle dosage forms decreased Cmax and increased Tmax and the mean residence time (MRT) values. Relative bioavailability was significantly increased with Eudragit nanoparticles compared to the nifedipine/PEG solution.There was an inverse linear correlation between the fall in blood pressure and plasma nifedipine concentration with all preparations.The nanoparticle nifedipine preparations represent sustained release forms with increased bioavailability, a less pronounced initial antihypertensive effect and a long-lasting action. PMID:9031742

Manganese Nanoparticle Activates Mitochondrial Dependent Apoptotic Signaling and Autophagy in Dopaminergic Neuronal Cells

PubMed Central

Ngwa, Hilary Afeseh; Kanthasamy, Arthi; Gu, Yan; Fang, Ning; Anantharam, Vellareddy; Kanthasamy, Anumantha G.

2011-01-01

The production of man-made nanoparticles for various modern applications has increased exponentially in recent years, but the potential health effects of most nanoparticles are not well characterized. Unfortunately, in vitro nanoparticle toxicity studies are extremely limited by yet unresolved problems relating to dosimetry. In the present study, we systematically characterized manganese (Mn) nanoparticle sizes and examined the nanoparticle-induced oxidative signaling in dopaminergic neuronal cells. Differential interference contrast (DIC) microscopy and transmission electron microscopy (TEM) studies revealed that Mn nanoparticles range in size from single nanoparticles (~25 nM) to larger agglomerates when in treatment media. Manganese nanoparticles were effectively internalized in N27 dopaminergic neuronal cells, and they induced a time-dependent upregulation of the transporter protein transferrin. Exposure to 25–400 µg/mL Mn nanoparticles induced cell death in a time- and dose-dependent manner. Mn nanoparticles also significantly increased ROS, accompanied by a caspase-mediated proteolytic cleavage of proapoptotic protein kinase Cδ (PKCδ), as well as activation loop phosphorylation. Blocking Mn nanoparticle-induced ROS failed to protect against the neurotoxic effects, suggesting the involvement of other pathways. Further mechanistic studies revealed changes in Beclin1 and LC3, indicating that Mn nanoparticles induce autophagy. Primary mesencephalic neuron exposure to Mn nanoparticles induced loss of TH positive dopaminergic neurons and neuronal processes. Collectively, our results suggest that Mn nanoparticles effectively enter dopaminergic neuronal cells and exert neurotoxic effects by activating an apoptotic signaling pathway and autophagy, emphasizing the need for assessing possible health risks associated with an increased use of Mn nanoparticles in modern applications. PMID:21856324

Titanium dioxide nanoparticles relieve silk gland damage and increase cocooning of Bombyx mori under phoxim-induced toxicity.

PubMed

Li, Bing; Yu, Xiaohong; Gui, Suxin; Xie, Yi; Hong, Jie; Zhao, Xiaoyang; Sheng, Lei; Sang, Xuezi; Sun, Qingqing; Wang, Ling; Shen, Weide; Hong, Fashui

2013-12-18

Organophosphate pesticides are applied widely in the world for agricultural purposes, and their exposures often resulted in non-cocooning of Bombyx mori in China. TiO2 nanoparticles have been demonstrated to increase pesticide resistance of Bombyx mori. While the toxicity of phoxim is well-documented, very limited information exists on the mechanisms of TiO2 nanoparticles improving the cocooning function of Bombyx mori following exposure to phoxim. The present study was, therefore, undertaken to determine whether TiO2 nanoparticles attenuate silk gland injury and elevate cocooning of B. mori following exposure to phoxim. The findings suggested that phoxim exposure resulted in severe damages of the silk gland structure and significantly decreased the cocooning in the silk gland of Bombyx mori. Furthermore, phoxim exposure significantly resulted in reductions of total protein concentrations and suppressed expressions of silk protein synthesis-related genes, including Fib-L, Fib-H, P25, Ser-2, and Ser-3, in the silk gland. TiO2 nanoparticle pretreatment, however, could significantly relieve silk gland injury of Bombyx mori. Importantly, TiO2 nanoparticles could remarkably elevate cocooning and total protein contents and promote expressions of Fib-L, Fib-H, P25, Ser-2, and Ser-3 in the silk gland following exposure to phoxim.

Improving the water solubility and antimicrobial activity of silymarin by nanoencapsulation.

PubMed

Lee, Ji-Soo; Hong, Da Young; Kim, Eun Suh; Lee, Hyeon Gyu

2017-06-01

The aims of this study were to improve the water solubility and antimicrobial activity of milk thistle silymarin by nanoencapsulation and to assess the functions of silymarin nanoparticle-containing film as an antimicrobial food-packaging agent. Silymarin nanoparticles were prepared using water-soluble chitosan (WCS) and poly-γ-glutamic acid (γ-PGA). As the WCS and silymarin concentrations increased, particle size and polydispersity index (PDI) significantly increased. Nanoencapsulation significantly improved the water solubility of silymarin 7.7-fold. Antimicrobial activity of silymarin was effectively improved when silymarin was entrapped within the nanocapsule compared to when it was not entrapped. Films incorporating silymarin nanoparticles had better antimicrobial activity than films incorporating free silymarin. The results suggest that silymarin nanoparticles have applications in antimicrobial food additives and food packing. Copyright © 2017 Elsevier B.V. All rights reserved.

Cytotoxicity and cellular uptake of different sized gold nanoparticles in ovarian cancer cells

NASA Astrophysics Data System (ADS)

Kumar, Dhiraj; Mutreja, Isha; Chitcholtan, Kenny; Sykes, Peter

2017-11-01

Nanomedicine has advanced the biomedical field with the availability of multifunctional nanoparticles (NPs) systems that can target a disease site enabling drug delivery and helping to monitor the disease. In this paper, we synthesised the gold nanoparticles (AuNPs) with an average size 18, 40, 60 and 80 nm, and studied the effect of nanoparticles size, concentration and incubation time on ovarian cancer cells namely, OVCAR5, OVCAR8, and SKOV3. The size measured by transmission electron microscopy images was slightly smaller than the hydrodynamic diameter; measured size by ImageJ as 14.55, 38.13, 56.88 and 78.56 nm. The cellular uptake was significantly controlled by the AuNPs size, concentration, and the cell type. The nanoparticles uptake increased with increasing concentration, and 18 and 80 nm AuNPs showed higher uptake ranging from 1.3 to 5.4 μg depending upon the concentration and cell type. The AuNPs were associated with a temporary reduction in metabolic activity, but metabolic activity remained more than 60% for all sample types; NPs significantly affected the cell proliferation activity in first 12 h. The increase in nanoparticle size and concentration induced the production of reactive oxygen species in 24 h.

Lyophilized insulin nanoparticles prepared from quaternized N-aryl derivatives of chitosan as a new strategy for oral delivery of insulin: in vitro, ex vivo and in vivo characterizations.

PubMed

Mahjub, Reza; Radmehr, Moojan; Dorkoosh, Farid Abedin; Ostad, Seyed Naser; Rafiee-Tehrani, Morteza

2014-12-01

The purpose of this research was the development, in vitro, ex vivo and in vivo characterization of lyophilized insulin nanoparticles prepared from quaternized N-aryl derivatives of chitosan. Insulin nanoparticles were prepared from methylated N-(4-N,N-dimethylaminobenzyl), methylated N-(4 pyridinyl) and methylated N-(benzyl). Insulin nanoparticles containing non-modified chitosan and also trimethyl chiotsan (TMC) were also prepared as control. The effects of the freeze-drying process on physico-chemical properties of nanoparticles were investigated. The release of insulin from the nanoparticles was studied in vitro. The mechanism of the release of insulin from different types of nanoparticles was determined using curve fitting. The secondary structure of the insulin released from the nanoparticles was analyzed using circular dichroism and the cell cytotoxicity of nanoparticles on a Caco-2 cell line was determined. Ex vivo studies were performed on excised rat jejunum using Frantz diffusion cells. In vivo studies were performed on diabetic male Wistar rats and blood glucose level and insulin serum concentration were determined. Optimized nanoparticles with proper physico-chemical properties were obtained. The lyophilization process was found to cause a decrease in zeta potential and an increase in PdI as well as and a decrease in entrapment efficiency (EE%) and loading efficiency (LE%) but conservation in size of nanoparticles. Atomic force microscopy (AFM) images showed non-aggregated, stable and spherical to sub-spherical nanoparticles. The in vitro release study revealed higher release rates for lyophilized compared to non-lyophilized nanoparticles. Cytotoxicity studies on Caco-2 cells revealed no significant cytotoxicity for prepared nanoparticles after 3-h post-incubation but did show the concentration-dependent cytotoxicity after 24 h. The percentage of cumulative insulin determined from ex vivo studies was significantly higher in nanoparticles prepared from quaternized aromatic derivatives of chitosan. In vivo data showed significantly higher insulin intestinal absorption in nanoparticles prepared from methylated N-(4-N, N-dimethylaminobenzyl) chitosan nanoparticles compared to trimethyl chitosan. These data obtained demonstrated that as the result of optimized physico-chemical properties, drug release rate, cytotoxicity profile, ex vivo permeation enhancement and increased in vivo absorption, nanoparticles prepared from N-aryl derivatives of chitosan can be considered as valuable method for the oral delivery of insulin.

Functionalization of gold nanoparticles as antidiabetic nanomaterial

NASA Astrophysics Data System (ADS)

Venkatachalam, M.; Govindaraju, K.; Mohamed Sadiq, A.; Tamilselvan, S.; Ganesh Kumar, V.; Singaravelu, G.

2013-12-01

In the present investigation, functionalization of gold nanoparticles synthesized using propanoic acid 2-(3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl) (PAT) an active biocomponent isolated from Cassia auriculata is studied in detail. On reaction of PAT with aqueous HAuCl4, rapid formation of stable gold nanoparticles was achieved. Formation of gold nanoparticles was confirmed by UV-vis spectroscopy, XRD, GC-MS, FTIR, TEM and SEM with EDAX. Gold nanoparticles mostly were monodisperse, spherical in shape and ranged in size 12-41 nm. Gold nanoparticles synthesised using PAT was administered to alloxan (150 mg/kg body weight) induced diabetic male albino rats at different doses (0.25, 0.5, 0.75 and 1.0 mg/kg body weight) for 28 days. Plasma glucose level, cholesterol and triglyceride were significantly (p < 0.001) reduced in experimental animals treated with gold nanoparticles at dosage of 0.5 mg/kg body weight and plasma insulin increased significantly. The newly genre green gold nanoparticles exhibit remarkable protein tyrosine phosphatase 1B inhibitory activity.

Peptide conjugated magnetic nanoparticles for magnetically mediated energy delivery to lung cancer cells

PubMed Central

Hauser, Anastasia K; Anderson, Kimberly W; Hilt, J Zach

2016-01-01

Aim: In the present study, we examine the effects of internalized peptide-conjugated iron oxide nanoparticles and their ability to locally convert alternating magnetic field (AMF) energy into other forms of energy (e.g., heat and rotational work). Materials & methods: Dextran-coated iron oxide nanoparticles were functionalized with a cell penetrating peptide and after internalization by A549 and H358 cells were activated by an AMF. Results: TAT-functionalized nanoparticles and AMF exposure increased reactive oxygen species generation compared with the nanoparticle system alone. The TAT-functionalized nanoparticles induced lysosomal membrane permeability and mitochondrial membrane depolarization, but these effects were not further enhanced by AMF treatment. Although not statistically significant, there are trends suggesting an increase in apoptosis via the Caspase 3/7 pathways when cells are exposed to TAT-functionalized nanoparticles combined with AMF. Conclusion: Our results indicate that internalized TAT-functionalized iron oxide nanoparticles activated by an AMF elicit cellular responses without a measurable temperature rise. PMID:27388639

Ultrasmall iron oxide nanoparticles for biomedical applications: improving the colloidal and magnetic properties.

PubMed

Costo, Rocio; Bello, Valentina; Robic, Caroline; Port, Marc; Marco, Jose F; Puerto Morales, M; Veintemillas-Verdaguer, Sabino

2012-01-10

A considerable increase in the saturation magnetization, M(s) (40%), and initial susceptibility of ultrasmall (<5 nm) iron oxide nanoparticles prepared by laser pyrolysis was obtained through an optimized acid treatment. Moreover, a significant enhancement in the colloidal properties, such as smaller aggregate sizes in aqueous media and increased surface charge densities, was found after this chemical protocol. The results are consistent with a reduction in nanoparticle surface disorder induced by a dissolution-recrystallization mechanism.

Cytotoxicity of titanium dioxide nanoparticles in mouse fibroblast cells.

PubMed

Jin, Cheng-Yu; Zhu, Bang-Shang; Wang, Xue-Feng; Lu, Qing-Hua

2008-09-01

Nanotitanium dioxide (TiO2) is an important industrial material that is widely used as an additive in cosmetics, pharmaceuticals, and food colorants. Although the small size of the TiO2 nanoparticle is useful in various applications, the biosafety of this material needs to be evaluated. In this study, mouse fibroblast (L929) cells were used to evaluate the cytotoxicity of different concentrations (3-600 microg/mL) of homogeneous and weakly aggregated TiO2 nanoparticles in aqueous solution. The L929 cells became round and even shrank as the concentration of TiO2 nanoparticles increased. Moreover, TiO2 nanoparticle-treated cells had condensed fragmented chromatin or were directly necrosed, as observed by acridine orange (AO) staining. The transmission electron microscopy (TEM) analysis showed that in cells cultured in a medium containing 300 microg/mL TiO2, the number of lysosomes increased, and some cytoplasmic organelles were damaged. In addition, there was a significant increase in oxidative stress at higher TiO2 nanoparticle concentrations (>60 microg/mL). As the concentration of TiO2 nanoparticles increased in the culture medium, the levels of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) increased, while those of methyl tetrazolium cytotoxicity (MTT), glutathione (GSH), and superoxide dismutase (SOD) decreased. A possible mechanism for the cytotoxicity of TiO2 nanoparticles is also discussed.

A Novel Docetaxel-Loaded Poly (ɛ-Caprolactone)/Pluronic F68 Nanoparticle Overcoming Multidrug Resistance for Breast Cancer Treatment

NASA Astrophysics Data System (ADS)

Mei, Lin; Zhang, Yangqing; Zheng, Yi; Tian, Ge; Song, Cunxian; Yang, Dongye; Chen, Hongli; Sun, Hongfan; Tian, Yan; Liu, Kexin; Li, Zhen; Huang, Laiqiang

2009-12-01

Multidrug resistance (MDR) in tumor cells is a significant obstacle to the success of chemotherapy in many cancers. The purpose of this research is to test the possibility of docetaxel-loaded poly (ɛ-caprolactone)/Pluronic F68 (PCL/Pluronic F68) nanoparticles to overcome MDR in docetaxel-resistance human breast cancer cell line. Docetaxel-loaded nanoparticles were prepared by modified solvent displacement method using commercial PCL and self-synthesized PCL/Pluronic F68, respectively. PCL/Pluronic F68 nanoparticles were found to be of spherical shape with a rough and porous surface. The nanoparticles had an average size of around 200 nm with a narrow size distribution. The in vitro drug release profile of both nanoparticle formulations showed a biphasic release pattern. There was an increased level of uptake of PCL/Pluronic F68 nanoparticles in docetaxel-resistance human breast cancer cell line, MCF-7 TAX30, when compared with PCL nanoparticles. The cytotoxicity of PCL nanoparticles was higher than commercial Taxotere® in the MCF-7 TAX30 cell culture, but the differences were not significant ( p > 0.05). However, the PCL/Pluronic F68 nanoparticles achieved significantly higher level of cytotoxicity than both of PCL nanoparticles and Taxotere® ( p < 0.05), indicating docetaxel-loaded PCL/Pluronic F68 nanoparticles could overcome multidrug resistance in human breast cancer cells and therefore have considerable potential for treatment of breast cancer.

Mechanistic Differences in DNA Nanoparticle Formation in the Presence of Oligolysines and Poly-L-lysine†

PubMed Central

Nayvelt, Irina; Thomas, Thresia; Thomas, T. J.

2008-01-01

We studied the effectiveness of trilysine (Lys3)-, tetralysine (Lys4)-, pentalysine (Lys5)-, and poly-L-lysine (PLL) (MW: 50,000) on λ-DNA nanoparticle formation, and characterized the size, shape and stability of nanoparticles. Light scattering experiments showed EC50 (lysine concentration at 50% DNA compaction) values of ~0.0036, 2, and 20 μmoles/liter, respectively, for PLL, Lys5, and Lys4 at 10 mM [Na+]. Plots of log[EC50] versus log[Na+] showed positive slopes of 1.09 and 1.7, respectively, for Lys4 and Lys5 and a negative slope of −0.1 for PLL. Hydrodynamic radii of oligolysine-condensed particles increased (48–173 nm) with increasing [Na+], whereas no significant change occurred to nanoparticles formed with PLL. There was an increase in the size of nanoparticles formed with Lys5 at >40 °C, whereas no such change occurred with PLL. DNA melting temperature increased with oligolysine concentration. These results indicate distinct differences in the mechanism(s) by which oligolysines and PLL provoke DNA condensation to nanoparticles. PMID:17291071

Preparation of a Nanoscaled Poly(vinyl alcohol)/Hydroxyapatite/DNA Complex Using High Hydrostatic Pressure Technology for In Vitro and In Vivo Gene Delivery.

PubMed

Kimura, Tsuyoshi; Nibe, Yoichi; Funamoto, Seiichi; Okada, Masahiro; Furuzono, Tsutomu; Ono, Tsutomu; Yoshizawa, Hidekazu; Fujisato, Toshiya; Nam, Kwangwoo; Kishida, Akio

2011-01-01

Our previous research showed that poly(vinyl alcohol) (PVA) nanoparticles incorporating DNA with hydrogen bonds obtained by high hydrostatic pressurization are able to deliver DNA without any significant cytotoxicity. To enhance transfection efficiency of PVA/DNA nanoparticles, we describe a novel method to prepare PVA/DNA nanoparticles encapsulating nanoscaled hydroxyapatites (HAps) prepared by high hydrostatic pressurization (980 MPa), which is designed to facilitate endosomal escape induced by dissolving HAps in an endosome. Scanning electron microscopic observation and dynamic light scattering measurement revealed that HAps were significantly encapsulated in PVA/HAp/DNA nanoparticles. The cytotoxicity, cellular uptake, and transgene expression of PVA/HAp/DNA nanoparticles were investigated using COS-7 cells. It was found that, in contrast to PVA/DNA nanoparticles, their internalization and transgene expression increased without cytotoxicity occurring. Furthermore, a similar level of transgene expression between plasmid DNA and PVA/HAp/DNA nanoparticles was achieved using in vivo hydrodynamic injection. Our results show a novel method of preparing PVA/DNA nanoparticles encapsulating HAp nano-crystals by using high hydrostatic pressure technology and the potential use of HAps as an enhancer of the transfection efficiency of PVA/DNA nanoparticles without significant cytotoxicity.

Thermal treatment to enhance saturation magnetization of superparamagnetic Ni nanoparticles while maintaining low coercive force

NASA Astrophysics Data System (ADS)

Ishizaki, Toshitaka; Yatsugi, Kenichi; Akedo, Kunio

2018-05-01

Superparamagnetic nanoparticles capped by insulators have the potential to decrease eddy current and hysteresis losses. However, the saturation magnetization ( M s) decreases significantly with decreasing the particle size. In this study, superparamagnetic Ni nanoparticles having the mean size of 11.6 ± 1.8 nm were synthesized from the reduction of Ni(II) acetylacetonate in oleylamine with the addition of trioctylphosphine, indicating the coercive force ( H c) less than 1 Oe. Thermal treatments of the Ni nanoparticles were investigated as a method to enhance the M s. The results indicated that the M s was enhanced by an increase of the Ni mass ratio with increasing thermal treatment temperature. However, the decomposition behavior of the capping layers indicated that their alkyl chains actively decomposed at temperatures above 523 K to form Ni3P via reaction between Ni and P, resulting in particle growth with a significant increase in the H c. Therefore, the optimal temperature was determined to be 473 K, which increased the Ni ratio without formation of Ni3P while maintaining particle sizes with superparamagnetic properties. Further, the M s could be improved by 22% (relative to the as-synthesized Ni nanoparticles) after thermal treatment at 473 K while maintaining the H c to be less than 1 Oe.

Evaluation of the cytotoxic and genotoxic potential of lecithin/chitosan nanoparticles

NASA Astrophysics Data System (ADS)

Taner, Gökçe; Yeşilöz, Recep; Özkan Vardar, Deniz; Şenyiğit, Taner; Özer, Özgen; Degen, Gisela H.; Başaran, Nurşen

2014-02-01

Nanoparticles-based drug targeting delivery systems have been introduced in the treatment for various diseases because of their effective properties, although there have been conflicting results on the toxicity of nanoparticles. In the present study, the aim was to evaluate the cytotoxicity and the genotoxicity of different concentrations of lecithin/chitosan nanoparticles with and without clobetasol-17-propionate (CP) by neutral red uptake (NRU) cytotoxicity assay and single cell gel electrophoresis (Comet) and cytokinesis-blocked micronucleus assays. The IC50 values of lecithin/chitosan nanoparticles with/without CP were found as 1.9 and 1.8 %, respectively, in the NRU cytotoxicity test. High concentrations of lecithin/chitosan nanoparticles induced DNA damage in human lymphocytes as evaluated by comet assay. The micronucleus frequency was increased by the lecithin/chitosan treatment in a dose-dependent manner. Also at the two highest concentrations, a significant increase in micronucleus formation was observed. Lecithin/chitosan nanoparticles with CP did not increase the frequency of micronucleus and also did not induce additional DNA damage when compared with lecithin/chitosan nanoparticles without CP; therefore, CP itself has not found to be genotoxic at the studied concentration.

Nanoparticle-mediated combination chemotherapy and photodynamic therapy overcomes tumor drug resistance.

PubMed

Khdair, Ayman; Chen, Di; Patil, Yogesh; Ma, Linan; Dou, Q Ping; Shekhar, Malathy P V; Panyam, Jayanth

2010-01-25

Tumor drug resistance significantly limits the success of chemotherapy in the clinic. Tumor cells utilize multiple mechanisms to prevent the accumulation of anticancer drugs at their intracellular site of action. In this study, we investigated the anticancer efficacy of doxorubicin in combination with photodynamic therapy using methylene blue in a drug-resistant mouse tumor model. Surfactant-polymer hybrid nanoparticles formulated using an anionic surfactant, Aerosol-OT (AOT), and a naturally occurring polysaccharide polymer, sodium alginate, were used for synchronized delivery of the two drugs. Balb/c mice bearing syngeneic JC tumors (mammary adenocarcinoma) were used as a drug-resistant tumor model. Nanoparticle-mediated combination therapy significantly inhibited tumor growth and improved animal survival. Nanoparticle-mediated combination treatment resulted in enhanced tumor accumulation of both doxorubicin and methylene blue, significant inhibition of tumor cell proliferation, and increased induction of apoptosis. These data suggest that nanoparticle-mediated combination chemotherapy and photodynamic therapy using doxorubicin and methylene blue has significant therapeutic potential against drug-resistant tumors. Copyright 2009 Elsevier B.V. All rights reserved.

Development and evaluation of polymer nanoparticles for oral delivery of estradiol to rat brain in a model of Alzheimer's pathology.

PubMed

Mittal, G; Carswell, H; Brett, R; Currie, S; Kumar, M N V Ravi

2011-03-10

The purpose of this study was to develop tween 80 (T-80) coated polylactide-co-glycolide (PLGA) nanoparticles that can deliver estradiol to the brain upon oral administration. Estradiol containing nanoparticles were made by a single emulsion technique and T-80 coating was achieved by incubating the re-constituted nanoparticles at different concentrations of T-80. The process of T-80 coating on the nanoparticles was optimized and the pharmacokinetics of estradiol nanoparticles was studied as a function of T-80 coating. The nanoparticles were then evaluated in an ovariectomized (OVX) rat model of Alzheimer's disease (AD) that mimics the postmenopausal conditions. The nanoparticles bound T-80 were found to proportionally increase from 9.72 ± 1.07 mg to 63.84 ± 3.59 mg with an increase in the initial concentration T-80 from 1% to 5% and were stable in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Orally administered T-80 coated nanoparticles resulted in significantly higher brain estradiol levels after 24h (1.969 ± 0.197 ng/g tissue) as compared to uncoated ones (1.105 ± 0.136 ng/g tissue) at a dose of 0.2mg/rat, suggesting a significant role of surface coating. Moreover, these brain estradiol levels were almost similar to those obtained after administration of the same dose of drug suspension via 100% bioavailable intramuscular route (2.123 ± 0.370 ng/g tissue), indicating the increased fraction of bioavailable drug reaching the brain when administered orally. Also, the nanoparticle treated group was successful in preventing the expression of amyloid beta-42 (Aβ42) immunoreactivity in the hippocampus region of brain. Together, the results indicate the potential of nanoparticles for oral delivery of estradiol to brain. Copyright © 2010 Elsevier B.V. All rights reserved.

Synthesis and characterization of near IR fluorescent albumin nanoparticles for optical detection of colon cancer.

PubMed

Cohen, Sarit; Pellach, Michal; Kam, Yossi; Grinberg, Igor; Corem-Salkmon, Enav; Rubinstein, Abraham; Margel, Shlomo

2013-03-01

Near IR (NIR) fluorescent human serum albumin (HSA) nanoparticles hold great promise as contrast agents for tumor diagnosis. HSA nanoparticles are considered to be biocompatible, non-toxic and non-immunogenic. In addition, NIR fluorescence properties of these nanoparticles are important for in vivo tumor diagnostics, with low autofluorescence and relatively deep penetration of NIR irradiation due to low absorption of biomatrices. The present study describes the synthesis of new NIR fluorescent HSA nanoparticles, by entrapment of a NIR fluorescent dye within the HSA nanoparticles, which also significantly increases the photostability of the dye. Tumor-targeting ligands such as peanut agglutinin (PNA) and anti-carcinoembryonic antigen antibodies (anti-CEA) were covalently conjugated to the NIR fluorescent albumin nanoparticles, increasing the potential fluorescent signal in tumors with upregulated corresponding receptors. Specific colon tumor detection by the NIR fluorescent HSA nanoparticles was demonstrated in a chicken embryo model and a rat model. In future work we also plan to encapsulate cancer drugs such as doxorubicin within the NIR fluorescent HSA nanoparticles for both colon cancer imaging and therapy. Copyright © 2012 Elsevier B.V. All rights reserved.

Fabrication of curcumin-loaded bovine serum albumin (BSA)-dextran nanoparticles and the cellular antioxidant activity.

PubMed

Fan, Yuting; Yi, Jiang; Zhang, Yuzhu; Yokoyama, Wallace

2018-01-15

Bovine serum albumin (BSA)-dextran conjugate was prepared with glycation. Self-assembly nanoparticles were synthesized with a green, and facile approach. The effects of dry-heating time on the fabrication and characteristics of BSA-dextran conjugate nanoparticles were examined. Stable nanoparticles (<200nm) were formed after only 6h dry-heating because enough dextran was grafted onto the BSA to provide significant steric hindrance. Particle size decreased with the increase of dry-heating time and the lowest particle size (51.2nm) was obtained after 24h dry-heating. The nanoparticles were stable in a wide pH range (pH 2.0-7.0). The particle size of nanoparticles increased to 115nm after curcumin incorporation and was stable even after one-month storage. TEM results demonstrated that curcumin-loaded nanoparticles displayed a spherical structure and were homogeneously dispersed. Curcumin in BSA-dextran nanoparticle showed better stability, compared to free curcumin. In addition, BSA-dextran nanoparticles can improve the cellular antioxidant activity of curcumin in Caco-2 cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of sub-acute exposure to TiO2, ZnO and Al2O3 nanoparticles on oxidative stress and histological changes in mouse liver and brain.

PubMed

Shrivastava, Rupal; Raza, Saimah; Yadav, Abhishek; Kushwaha, Pramod; Flora, Swaran J S

2014-07-01

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. However the information regarding toxicity of these nanoparticles on humans and environment is still deficient. The present study investigated the toxic effects of three metal oxide nanoparticles, TiO2, ZnO and Al2O3 on mouse erythrocytes, brain and liver. Male mice were administered a single oral dose of 500 mg/kg of each nanoparticles for 21 consecutive days. The results suggest that exposure to these nano metallic particles produced a significant oxidative stress in erythrocyte, liver and brain as evident from enhanced levels of Reactive Oxygen Species (ROS) and altered antioxidant enzymes activities. A significant increase in dopamine and norepinephrine levels in brain cerebral cortex and increased brain oxidative stress suggest neurotoxic potential of these nanoparticles. Transmission electron microscopic (TEM) analysis indicated the presence of these nanoparticles inside the cytoplasm and nucleus. These changes were also supported by the inhibition of CuZnSOD and MnSOD, considered as important biomarkers of oxidative stress. The toxic effects produced by these nanoparticles were more pronounced in the case of zinc oxide, followed by aluminum oxide and titanium dioxide, respectively. The present results further suggest the involvement of oxidative stress as one of the main mechanisms involved in nanoparticles induced toxic manifestations.

Magnetic and resonance properties of ferrihydrite nanoparticles doped with cobalt

NASA Astrophysics Data System (ADS)

Stolyar, S. V.; Yaroslavtsev, R. N.; Iskhakov, R. S.; Bayukov, O. A.; Balaev, D. A.; Dubrovskii, A. A.; Krasikov, A. A.; Ladygina, V. P.; Vorotynov, A. M.; Volochaev, M. N.

2017-03-01

Powders of undoped ferrihydrite nanoparticles and ferrihydrite nanoparticles doped with cobalt in the ratio of 5: 1 have been prepared by hydrolysis of 3 d-metal salts. It has been shown using Mössbauer spectroscopy that cobalt is uniformly distributed over characteristic crystal-chemical positions of iron ions. The blocking temperatures of ferrihydrite nanoparticles have been determined. The nanoparticle sizes, magnetizations, surface anisotropy constants, and bulk anisotropy constants have been estimated. The doping of ferrihydrite nanoparticles with cobalt leads to a significant increase in the anisotropy constant of a nanoparticle and to the formation of surface rotational anisotropy with the surface anisotropy constant K u = 1.6 × 10-3 erg/cm2.

Exchange of TiO2 nanoparticles between streams and streambeds.

PubMed

Boncagni, Natalia Ticiana; Otaegui, Justo Manuel; Warner, Evelyn; Curran, Trisha; Ren, Jianhong; de Cortalezzi, Maria Marta Fidalgo

2009-10-15

The expanding use of manufactured nanoparticles has increased the potential for their release into the natural environment. Particularly, TiO2 nanoparticles pose significant exposure risk to humans and other living species due to their extensive use in a wide range of fields. To better understand the environmental and health risks associated with the release of TiO2 nanoparticles, knowledge on their fate and transport is needed. This study evaluates the transport of two different TiO2 nanoparticles: one commercially available (P25 TiO2 and the other synthesized at a lab scale (synthesized TiO2). Laboratory flume, column, and batch experiments were conducted to investigate the processes dominating the transport of TiO2 nanoparticles between streams and streambeds and to characterize the properties of these nanoparticles under different physicochemical conditions. Results show that the synthesized TiO2 was more stable compared to the P25 TiO2, which underwent significant aggregation under the same experimental conditions. As a result, P25 TiO2 deposited at a faster rate than the synthesized TiO2 in the streambed. Both types of TiO2 nanoparticles deposited in the streambed were easily released when the stream velocity was increased. The aggregation and deposition of P25 TiO2 were highly dependent on pH. A process-based colloid exchange model was applied to interpret the observed transport behavior of the TiO2 nanoparticles.

Targeted nanoparticle delivery of therapeutic antisense microRNAs presensitizes glioblastoma cells to lower effective doses of temozolomide in vitro and in a mouse model.

PubMed

Malhotra, Meenakshi; Sekar, Thillai Veerapazham; Ananta, Jeyarama S; Devulapally, Rammohan; Afjei, Rayhaneh; Babikir, Husam A; Paulmurugan, Ramasamy; Massoud, Tarik F

2018-04-20

Temozolomide (TMZ) chemotherapy for glioblastoma (GBM) is generally well tolerated at standard doses but it can cause side effects. GBMs overexpress microRNA-21 and microRNA-10b, two known oncomiRs that promote cancer development, progression and resistance to drug treatment. We hypothesized that systemic injection of antisense microRNAs (antagomiR-21 and antagomiR-10b) encapsulated in cRGD-tagged PEG-PLGA nanoparticles would result in high cellular delivery of intact functional antagomiRs, with consequent efficient therapeutic response and increased sensitivity of GBM cells to lower doses of TMZ. We synthesized both targeted and non-targeted nanoparticles, and characterized them for size, surface charge and encapsulation efficiency of antagomiRs. When using targeted nanoparticles in U87MG and Ln229 GBM cells, we showed higher uptake-associated improvement in sensitivity of these cells to lower concentrations of TMZ in medium. Co-inhibition of microRNA-21 and microRNA-10b reduced the number of viable cells and increased cell cycle arrest at G2/M phase upon TMZ treatment. We found a significant increase in expression of key target genes for microRNA-21 and microRNA-10b upon using targeted versus non-targeted nanoparticles. There was also significant reduction in tumor volume when using TMZ after pre-treatment with loaded nanoparticles in human GBM cell xenografts in mice. In vivo targeted nanoparticles plus different doses of TMZ showed a significant therapeutic response even at the lowest dose of TMZ, indicating that preloading cells with antagomiR-21 and antagomiR-10b increases cellular chemosensitivity towards lower TMZ doses. Future clinical applications of this combination therapy may result in improved GBM response by using lower doses of TMZ and reducing nonspecific treatment side effects.

The Effect of ZrO₂ Nanoparticles on the Microstructure and Properties of Sintered WC-Bronze-Based Diamond Composites.

PubMed

Sun, Youhong; Wu, Haidong; Li, Meng; Meng, Qingnan; Gao, Ke; Lü, Xiaoshu; Liu, Baochang

2016-05-06

Metal matrix-impregnated diamond composites are widely used in diamond tool manufacturing. In order to satisfy the increasing engineering requirements, researchers have paid more and more attention to enhancing conventional metal matrices by applying novel methods. In this work, ZrO₂ nanoparticles were introduced into the WC-bronze matrix with and without diamond grits via hot pressing to improve the performance of conventional diamond composites. The effects of ZrO₂ nanoparticles on the microstructure, density, hardness, bending strength, and wear resistance of diamond composites were investigated. The results indicated that the hardness and relative density increased, while the bending strength decreased when the content of ZrO₂ nanoparticles increased. The grinding ratio of diamond composites increased significantly by 60% as a result of nano-ZrO₂ addition. The enhancement mechanism was discussed. Diamond composites showed the best overall properties with the addition of 1 wt % ZrO₂ nanoparticles, thus paving the way for further applications.

The Effect of ZrO2 Nanoparticles on the Microstructure and Properties of Sintered WC–Bronze-Based Diamond Composites

PubMed Central

Sun, Youhong; Wu, Haidong; Li, Meng; Meng, Qingnan; Gao, Ke; Lü, Xiaoshu; Liu, Baochang

2016-01-01

Metal matrix-impregnated diamond composites are widely used in diamond tool manufacturing. In order to satisfy the increasing engineering requirements, researchers have paid more and more attention to enhancing conventional metal matrices by applying novel methods. In this work, ZrO2 nanoparticles were introduced into the WC–bronze matrix with and without diamond grits via hot pressing to improve the performance of conventional diamond composites. The effects of ZrO2 nanoparticles on the microstructure, density, hardness, bending strength, and wear resistance of diamond composites were investigated. The results indicated that the hardness and relative density increased, while the bending strength decreased when the content of ZrO2 nanoparticles increased. The grinding ratio of diamond composites increased significantly by 60% as a result of nano-ZrO2 addition. The enhancement mechanism was discussed. Diamond composites showed the best overall properties with the addition of 1 wt % ZrO2 nanoparticles, thus paving the way for further applications. PMID:28773469

Fluorescent nanoparticles based on AIE fluorogens for bioimaging.

PubMed

Yan, Lulin; Zhang, Yan; Xu, Bin; Tian, Wenjing

2016-02-07

Fluorescent nanoparticles (FNPs) have recently attracted increasing attention in the biomedical field because of their unique optical properties, easy fabrication and outstanding performance in imaging. Compared with conventional molecular probes including small organic dyes and fluorescent proteins, FNPs based on aggregation-induced emission (AIE) fluorogens have shown significant advantages in tunable emission and brightness, good biocompatibility, superb photo- and physical stability, potential biodegradability and facile surface functionalization. In this review, we summarize the latest advances in the development of fluorescent nanoparticles based on AIE fluorogens including polymer nanoparticles and silica nanoparticles over the past few years, and the various biomedical applications based on these fluorescent nanoparticles are also elaborated.

Chemical synthesis of L10 Fe-Pt-Ni alloy nanoparticles

NASA Astrophysics Data System (ADS)

Deepchand, Vimal; Abel, Frank M.; Tzitzios, Vasileios; Hadjipanayis, George C.

2018-05-01

This work focuses on the study of the magnetic and structural properties of chemically synthesized FePt1-xNix nanoparticles, with Ni content x in the range 0.2-0.4. We report the effect of Ni substitution on the L10 structure, on both the as-synthesized and annealed nanoparticles. A decrease in nanoparticle size as well as in chemical order is observed with an increase in Ni content, for both the as-made and annealed nanoparticles. The results also show that the post annealing procedure at 700oC significantly enhanced the L10 ordering of the nanoparticles. Substitution of nickel leads to a decrease in coercivity from 14.9 kOe in FePt to 0.8 kOe for FePt0.6Ni0.4 alloy, while the magnetization at 3 T is increased from 48 emu/g to 88 emu/g.

Synthesis of a specific monolithic column with artificial recognition sites for L-glutamic acid via cryo-crosslinking of imprinted nanoparticles.

PubMed

Göktürk, Ilgım; Üzek, Recep; Uzun, Lokman; Denizli, Adil

2016-06-01

In this study, a new molecular imprinting (MIP)-based monolithic cryogel column was prepared using chemically crosslinked molecularly imprinted nanoparticles, to achieve a simplified chromatographic separation (SPE) for a model compound, L-glutamic acid (L-Glu). Cryogelation through crosslinking of imprinted nanoparticles forms stable monolithic cryogel columns. This technique reduces the leakage of nanoparticles and increases the surface area, while protecting the structural features of the cryogel for stable and efficient recognition of the template molecule. A non-imprinted monolithic cryogel column (NIP) was also prepared, using non-imprinted nanoparticles produced without the addition of L-Glu during polymerization. The molecularly imprinted monolithic cryogel column (MIP) indicates apparent recognition selectivity and a good adsorption capacity compared to the NIP. Also, we have achieved a significant increase in the adsorption capacity, using the advantage of high surface area of the nanoparticles.

Silvernanotherapy on the viral borne disease of silkworm Bombyx mori L.

NASA Astrophysics Data System (ADS)

Govindaraju, K.; Tamilselvan, S.; Kiruthiga, V.; Singaravelu, G.

2011-12-01

Antiviral assays of chemically and biologically synthesized silver nanoparticles were made against BmNPV ( Bombyx mori Nuclear Polyhedrosis Virus). Reduction of silver ions by sodium citrate and Spirulina platensis led to the formation of spherical silver nanoparticles of 40-60 and 7-16 nm size. Single cell protein ( Spirulina platensis)-synthesized silver nanoparticles showed the strongest antiviral activity. Immunological studies made on the silkworm Bombyx mori disclosed that a significant increase in the total hemocyte count and differential hemocyte count due to S. platensis-synthesized silver nanoparticles supplementation. Improvement in the defense mechanism was noticed from the strengthened peritrophic membrane of the digestive tract and the increased total protein. Overall, the results presented illustrate that single cell protein-synthesized silver nanoparticles supplementation is effective in controlling viral-borne diseases of the silkworm.

Enhancement of radiation effect on cancer cells by gold-pHLIP

PubMed Central

Antosh, Michael P.; Wijesinghe, Dayanjali D.; Shrestha, Samana; Lanou, Robert; Huang, Yun Hu; Hasselbacher, Thomas; Fox, David; Neretti, Nicola; Sun, Shouheng; Katenka, Natallia; Cooper, Leon N; Andreev, Oleg A.; Reshetnyak, Yana K.

2015-01-01

Previous research has shown that gold nanoparticles can increase the effectiveness of radiation on cancer cells. Improved radiation effectiveness would allow lower radiation doses given to patients, reducing adverse effects; alternatively, it would provide more cancer killing at current radiation doses. Damage from radiation and gold nanoparticles depends in part on the Auger effect, which is very localized; thus, it is important to place the gold nanoparticles on or in the cancer cells. In this work, we use the pH-sensitive, tumor-targeting agent, pH Low-Insertion Peptide (pHLIP), to tether 1.4-nm gold nanoparticles to cancer cells. We find that the conjugation of pHLIP to gold nanoparticles increases gold uptake in cells compared with gold nanoparticles without pHLIP, with the nanoparticles distributed mostly on the cellular membranes. We further find that gold nanoparticles conjugated to pHLIP produce a statistically significant decrease in cell survival with radiation compared with cells without gold nanoparticles and cells with gold alone. In the context of our previous findings demonstrating efficient pHLIP-mediated delivery of gold nanoparticles to tumors, the obtained results serve as a foundation for further preclinical evaluation of dose enhancement. PMID:25870296

Green Synthesis of Nanoparticles and Nanocatalysts

EPA Science Inventory

Commercial and research interest in nanotechnology significantly increased in the past several years translating into more than US$9 billion in investment from public and private sources (Eckelman et al., 2008). Nanoparticles are generally defined as particulate complex matter wi...

Monitoring the Environmental Impact of TiO2 Nanoparticles Using a Plant-Based Sensor Network

PubMed Central

Lenaghan, Scott C.; Li, Yuanyuan; Zhang, Hao; Burris, Jason N.; Stewart, C. Neal; Parker, Lynne E.; Zhang, Mingjun

2016-01-01

The increased manufacturing of nanoparticles for use in cosmetics, foods, and clothing necessitates the need for an effective system to monitor and evaluate the potential environmental impact of these nanoparticles. The goal of this research was to develop a plant-based sensor network for characterizing, monitoring, and understanding the environmental impact of TiO2 nanoparticles. The network consisted of potted Arabidopsis thaliana with a surrounding water supply, which was monitored by cameras attached to a laptop computer running a machine learning algorithm. Using the proposed plant sensor network, we were able to examine the toxicity of TiO2 nanoparticles in two systems: algae and terrestrial plants. Increased terrestrial plant growth was observed upon introduction of the nanoparticles, whereas algal growth decreased significantly. The proposed system can be further automated for high-throughput screening of nanoparticle toxicity in the environment at multiple trophic levels. The proposed plant-based sensor network could be used for more accurate characterization of the environmental impact of nanomaterials. PMID:28458617

Characterization of bidisperse magnetorheological fluids utilizing maghemite (γ-Fe2O3) nanoparticles synthetized by flame spray pyrolysis

NASA Astrophysics Data System (ADS)

Jönkkäri, I.; Sorvali, M.; Huhtinen, H.; Sarlin, E.; Salminen, T.; Haapanen, J.; Mäkelä, J. M.; Vuorinen, J.

2017-09-01

In this study we have used liquid flame spray (LFS) process to synthetize γ-Fe2O3 nanoparticles of two different average sizes. Different sized nanoparticles were generated with two different liquid precursor feed rates in the spray process, higher feed rate resulting in larger nanoparticles with higher saturation magnetization. The nanoparticles were used in bidisperse magnetorheological fluids to substitute 5% of the micron sized carbonyl iron particles. To our knowledge this is the first time particles synthetized by the LFS method have been used in magnetorheological fluids. The bidisperse fluids showed significantly improved sedimentation stability compared to a monodisperse suspension with the same solid concentration. The tradeoff was an increased viscosity without magnetic field. The effect of the nanoparticles on the rheological properties under external magnetic field was modest. Finally, the dynamic oscillatory testing was used to evaluate the structural changes in the fluids under magnetic field. The addition of nanoparticles decreased the elastic portion of the deformation and increased the viscous portion.

Evaluation of the nutrient profile of Trachyspermum ammi L. seed under the influence of nanoparticles during germination.

PubMed

Ahmad, I Z; Fatima, U; Tabassum, H; Mabood, A; Ahmad, A; Srivastava, G; Das, M

2017-07-31

Trachyspermum ammi L. commonly known as Ajwain is an annual herb belonging to the family Apiaceae. It is enormously grown in Egypt, Iran, Pakistan, Afghanistan, and India as well as European region. Seeds of Ajwain were highly administered by traditional healers and usually employed for different ailments. Nanomaterials are known to have plant growth promoting effects, which could find applications in agriculture. In this study, the nanoparticles (NPs) showed the potential to enhance the primary metabolites when administered during germination. Therefore, nanoparticles elicitation can be used to increase the productivity, nutritional values and metabolite contents in Trachyspermum ammi L. This study aimed to provide new insight of the potential growth promoting effects of the nanoparticles () on plant system. Different concentrations of two nanoparticles, that is, iron pyrite (FeS2) and molybdenum disulphide (MoS2) at three different concentrations of 25ug/ml, 50ug/ml and 75ug/ml were tested on the seeds of Trachyspermum ammi L. The data indicated that nanoparticles enhanced the seedling growth as greener leafs and increased lengths of epicotyl and hypocotyls were seen. These nanoparticles also showed the potential to increase the contents of primary metabolites during germination and the total soluble protein content in seed was increased in nanoparticles-treated seeds as compared to control. The total protein profiling by SDS-PAGE indicated significant differences in number and molecular weights of protein bands upon exposure to nanoparticles.

Comparison of PLGA and lecithin/chitosan nanoparticles for dermal targeting of betamethasone valerate.

PubMed

Özcan, Ipek; Azizoğlu, Erkan; Senyiğit, Taner; Özyazici, Mine; Özer, Özgen

2013-07-01

Poly(lactide-co-glycolide) (PLGA) and lecithin/chitosan (LC) nanoparticles were prepared to evaluate the difference in the behavior upon administration on skin, for steroidal treatment. For this purpose, betamethasone-17-valerate (BMV)-loaded nanoparticles with a narrow size distribution and high entrapment efficiency were prepared. Permeation studies showed that both polymeric nanoparticles enhanced the amount of BMV in epidermis, which is the target site of topical steroidal treatment, when compared with commercial formulation. 1.58-Fold increase was determined in the epidermis concentration of BMV by LC nanoparticles with respect to PLGA nanoparticles. Nanoparticles were diluted in chitosan gel (10%, w/w) to prepare suitable formulation for topical application. Accumulation from both gel formulations were found significantly higher than commercial formulation in skin layers (p < 0.05). In addition, pharmacodynamic responses were also investigated as anti-inflammatory and skin-blanching parameters. Both formulations significantly improved these parameters although they contained 10 times less amount of BMV than commercial cream. Moreover, TEWL measurement exhibited no barrier function changes upon the application of nanoparticles on skin. Overall, both nanoparticles improved the localization of BMV within skin layers; but when compared with PLGA nanoparticles, the LC nanoparticles could be classified as a better candidate for topical delivery vehicle in the treatment of various dermatological inflammatory diseases.

Development and characterization of the kefiran-whey protein isolate-TiO2 nanocomposite films.

PubMed

Zolfi, Mohsen; Khodaiyan, Faramarz; Mousavi, Mohammad; Hashemi, Maryam

2014-04-01

Biodegradable kefiran-whey protein isolate (WPI)-titanium dioxide (TiO2) blend films were developed and characterized as a function of incorporating amount of TiO2 nanoparticles (1, 3 and 5% wt.). Results showed that the water vapor permeability, moisture content, moisture absorption and water solubility decreased by increasing the nano-TiO2 content. Mechanical tests revealed the plasticizing effect of TiO2 nanoparticles on the kefiran-WPI-TiO2 film. Addition of TiO2 nanoparticles to kefiran-WPI films significantly decreased tensile strength and Young's modulus, while increased its elongation at break. Differential scanning calorimetry data indicated that the glass transition temperature significantly changed by adding nano-TiO2. X-ray diffraction analysis also demonstrated that crystal type in kefiran-WPI was not affected by incorporation of TiO2 nanoparticles. A uniform distribution at 1 and 3% wt. loading levels of TiO2 nanoparticles was observed using scanning electron microscopy (SEM) micrographs. Copyright © 2014 Elsevier B.V. All rights reserved.

Controllable synthesis of iron oxide nanoparticles in porous NaCl matrix

NASA Astrophysics Data System (ADS)

Kurapov, Yury A.; E Litvin, Stanislav; Romanenko, Sergey M.; Didikin, Gennadii G.; Oranskaya, Elena I.

2017-03-01

The paper gives the results of studying the structure of porous condensates of Fe + NaCl composition, chemical and phase compositions and dimensions of nanoparticles produced from the vapor phase by EB-PVD. Iron nanoparticles at fast removal from the vacuum oxidize in air and possess significant sorption capacity relative to oxygen and moisture. At heating in air, reduction of porous condensate weight occurs right to the temperature of 650 °C, primarily, due to desorption of physically sorbed moisture. Final oxidation of Fe3O4 to Fe2O3 proceeds in the range of 380 °C-650 °C, due to the remaining fraction of physically adsorbed oxygen. At iron concentrations of up to 10-15 at%, condensate sorption capacity is markedly increased with increase of iron concentration, i.e. of the quantity of fine particles. Increase of condensation temperature is accompanied by increase of nanoparticle size, resulting in a considerable reduction of the total area of nanoparticle surface, and, hence of their sorption capacity. In addition to condensation temperature, the size and phase composition of nanoparticles can also be controlled by heat treatment of initial condensate, produced at low condensation temperatures. Magnetite nanoparticles can be transferred into stable colloid systems.

Effect of Zinc and Copper Nanoparticles on Drought Resistance of Wheat Seedlings

NASA Astrophysics Data System (ADS)

Taran, Nataliya; Storozhenko, Volodymyr; Svietlova, Nataliia; Batsmanova, Ludmila; Shvartau, Viktor; Kovalenko, Mariia

2017-01-01

The effect of a colloidal solution of Cu,Zn-nanoparticles on pro-oxidative/antioxidative balance and content of photosynthetic pigments and leaf area of winter wheat plants of steppe (Acveduc) and forest-steppe (Stolichna) ecotypes was investigated in drought conditions. It has been shown that Cu,Zn-nanoparticles decreased the negative effect of drought action upon plants of steppe ecotype Acveduc. In particular, increased activity of antioxidative enzymes reduced the level of accumulation of thiobarbituric acid reactive substances (TBARS) and stabilized the content of photosynthetic pigments and increased relative water content in leaves. Colloidal solution of Cu,Zn-nanoparticles had less significant influence on these indexes in seedlings of the Stolichna variety under drought.

Nanoparticles and nanofibers for topical drug delivery

PubMed Central

Goyal, Ritu; Macri, Lauren K.; Kaplan, Hilton M.; Kohn, Joachim

2016-01-01

This review provides the first comprehensive overview of the use of both nanoparticles and nanofibers for topical drug delivery. Researchers have explored the use of nanotechnology, specifically nanoparticles and nanofibers, as drug delivery systems for topical and transdermal applications. This approach employs increased drug concentration in the carrier, in order to increase drug flux into and through the skin. Both nanoparticles and nanofibers can be used to deliver hydrophobic and hydrophilic drugs and are capable of controlled release for a prolonged period of time. The examples presented provide significant evidence that this area of research has—and will continue to have — a profound impact on both clinical outcomes and the development of new products. PMID:26518723

Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer

NASA Astrophysics Data System (ADS)

Jiang, Liqin; Li, Xuemin; Liu, Lingrong; Zhang, Qiqing

2013-02-01

Oral chemotherapy is a key step towards `chemotherapy at home', a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer.

Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer

PubMed Central

2013-01-01

Oral chemotherapy is a key step towards ‘chemotherapy at home’, a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer. PMID:23394588

Enhancement of anti-stokes sensitized luminescence in AgCl(I) crystals in the presence of silver nanoparticles

NASA Astrophysics Data System (ADS)

Chung, Nguyen Thi Kim; Egorushina, E. A.; Latyshev, A. N.; Ovchinnikov, O. V.; Smirnov, M. S.; Suvorova, T. I.

2012-01-01

We have observed a significant increase in the intensity with anti-Stokes excitation of recombination luminescence in AgCl(I) microcrystals sensitized by methylene blue molecules in the presence of silver nanoparticles.

Role of SiO2 coating in multiferroic CoCr2O4 nanoparticles

NASA Astrophysics Data System (ADS)

Kamran, M.; Ullah, Asmat; Mehmood, Y.; Nadeem, K.; Krenn, H.

2017-02-01

Effect of silica (SiO2) coating concentration on structural and magnetic properties of multiferroic cobalt chromite (CoCr2O4) nanoparticles have been studied. The nanoparticles with average crystallite size in the range 19 to 28 nm were synthesised by sol-gel method. X-ray diffraction (XRD) analysis has verified the composition of single-phase cubic normal spinel structure of CoCr2O4 nanoparticles. The average crystallite size and cell parameter decreased with increasing SiO2 concentration. TEM image revealed that the shape of nanoparticles was non-spherical. Zero field cooled/field cooled (ZFC/FC) curves revealed that nanoparticles underwent a transition from paramagnetic (PM) state to collinear short-range ferrimagnetic (FiM) state, and this PM-FiM transition temperature decreased from 101 to 95 K with increasing SiO2 concentration or decreasing crystallite size. A conical spin state at Ts = 27 K was also observed for all the samples which decreased with decreasing average crystallite size. Low temperature lock-in transition was also observed in these nanoparticles at 12 K for uncoated nanoparticles which slightly shifted towards low temperature with decreasing average crystallite size. Saturation magnetization (Ms) showed decreasing trend with increasing SiO2 concentration, which was due to decrease in average crystallite size of nanoparticles and enhanced surface disorder in smaller nanoparticles. The temperature dependent AC-susceptibility also showed the decrease in the transition temperature (Tc), broadening of the Tc peak and decrease in magnetization with increasing SiO2 concentration or decreasing average crystallite size. In summary, the concentration of SiO2 has significantly affected the structural and magnetic properties of CoCr2O4 nanoparticles.

Cell-delivered magnetic nanoparticles caused hyperthermia-mediated increased survival in a murine pancreatic cancer model.

PubMed

Basel, Matthew T; Balivada, Sivasai; Wang, Hongwang; Shrestha, Tej B; Seo, Gwi Moon; Pyle, Marla; Abayaweera, Gayani; Dani, Raj; Koper, Olga B; Tamura, Masaaki; Chikan, Viktor; Bossmann, Stefan H; Troyer, Deryl L

2012-01-01

Using magnetic nanoparticles to absorb alternating magnetic field energy as a method of generating localized hyperthermia has been shown to be a potential cancer treatment. This report demonstrates a system that uses tumor homing cells to actively carry iron/iron oxide nanoparticles into tumor tissue for alternating magnetic field treatment. Paramagnetic iron/ iron oxide nanoparticles were synthesized and loaded into RAW264.7 cells (mouse monocyte/ macrophage-like cells), which have been shown to be tumor homing cells. A murine model of disseminated peritoneal pancreatic cancer was then generated by intraperitoneal injection of Pan02 cells. After tumor development, monocyte/macrophage-like cells loaded with iron/ iron oxide nanoparticles were injected intraperitoneally and allowed to migrate into the tumor. Three days after injection, mice were exposed to an alternating magnetic field for 20 minutes to cause the cell-delivered nanoparticles to generate heat. This treatment regimen was repeated three times. A survival study demonstrated that this system can significantly increase survival in a murine pancreatic cancer model, with an average post-tumor insertion life expectancy increase of 31%. This system has the potential to become a useful method for specifically and actively delivering nanoparticles for local hyperthermia treatment of cancer.

The toxic effects of silver nanoparticles on blood mononuclear cells.

PubMed

Barkhordari, A; Barzegar, S; Hekmatimoghaddam, H; Jebali, A; Rahimi Moghadam, S; Khanjani, N

2014-07-01

Nanoparticles have become one of the leading technologies over the past two years. The extensive use of nanoparticles has raised great concern about their occupational fate and biological effects. With an increase in the production and use of nanomaterial, it is more likely to get exposed to them occupationally and environmentally. To assess the toxicity of silver nanoparticles on human mononuclear cells. In this in vitro experimental study, suspensions of blood mononuclear cells from 10 young healthy men were incubated with 10-nm silver nanoparticles in different concentrations (range: 1-500 μg/mL) for 6 and 24 hours by MTT assay. Positive and negative controls were used for comparison. After 6 hours of exposure, 10.9% to 48.4% of the cells died. After 24 hours of exposure, the rate ranged from 56.8% to 86.3%. Regardless of the exposure time, the maximum cytotoxicity was observed at the concentration of 500 μg/mL of silver nanoparticles. By increasing the exposure time to 24 hours, the cytotoxicity of nanoparticles substantially increased at all concentrations. Cell death was significantly higher when compared to the controls (p<0.01). Silver nanoparticles possess both time- and dose-dependent cytotoxicity and can thus be considered as very toxic for mononuclear cells.

Nanoparticles as a Novel Delivery Vehicle for Therapeutics Targeting Erectile Dysfunction

PubMed Central

Han, George; Tar, Moses; Kuppam, Dwaraka S. R.; Friedman, Adam; Melman, Arnold; Friedman, Joel; Davies, Kelvin P.

2010-01-01

Introduction Nanoparticles represent a potential novel mechanism for transdermal delivery of erectogenic agents directly to the penis. Aim To determine if nanoparticles encapsulating known erectogenic agents (tadalafil, sialorphin, and nitric oxide [NO]) can improve erectile function in a rat model of erectile dysfunction (ED) as a result of aging (the Sprague-Dawley retired breeder rat). Methods Nanoparticles encapsulating the erectogenic agents were applied as a gel to the glans and penile shaft of anesthetized Sprague-Dawley rats and the intracorporal pressure/blood pressure (ICP/BP) monitored for up to 2 hours with or without stimulation of the cavernous nerve. Control nanoparticles were made without encapsulating erectogenic agents and applied in a similar manner in separate experiments. Results Nanoparticles encapsulating NO caused spontaneous visible erections in the rat, with an average time of onset of 4.5 minutes, duration of 1.42 minutes, and ICP/BP of 0.67 ± 0.14. The sialorphin nanoparticles also caused visible spontaneous erections after an average of 4.5 minutes, with a duration of 8 minutes and ICP/BP ratio of 0.72 ± 0.13. The difference in the erectile response between groups of animals treated with NO or sialorphin nanoparticles was significantly different from the control group treated with empty nanoparticles (P < 0.05) Tadalafil nanoparticles showed a significant increase in the mean ICP/BP (0.737 ± 0.029) following stimulation of the cavernous nerve (4 mA) 1 hour after application of the nanoparticles with a visibly improved erectile response. Conclusions Nanoparticles encapsulating three different erectogenic agents resulted in increased erectile function when applied to the penis of a rat model of ED. Nanoparticles represent a potential novel route for topical delivery of erectogenic agents which could improve the safety profile for existing orally administered drugs by avoiding effects of absorption and first-pass metabolism, and would be less hazardous than injection. PMID:19765204

Nanoparticles as a novel delivery vehicle for therapeutics targeting erectile dysfunction.

PubMed

Han, George; Tar, Moses; Kuppam, Dwaraka S R; Friedman, Adam; Melman, Arnold; Friedman, Joel; Davies, Kelvin P

2010-01-01

Nanoparticles represent a potential novel mechanism for transdermal delivery of erectogenic agents directly to the penis. To determine if nanoparticles encapsulating known erectogenic agents (tadalafil, sialorphin, and nitric oxide [NO]) can improve erectile function in a rat model of erectile dysfunction (ED) as a result of aging (the Sprague-Dawley retired breeder rat). Nanoparticles encapsulating the erectogenic agents were applied as a gel to the glans and penile shaft of anesthetized Sprague-Dawley rats and the intracorporal pressure/blood pressure (ICP/BP) monitored for up to 2 hours with or without stimulation of the cavernous nerve. Control nanoparticles were made without encapsulating erectogenic agents and applied in a similar manner in separate experiments. Nanoparticles encapsulating NO caused spontaneous visible erections in the rat, with an average time of onset of 4.5 minutes, duration of 1.42 minutes, and ICP/BP of 0.67 +/- 0.14. The sialorphin nanoparticles also caused visible spontaneous erections after an average of 4.5 minutes, with a duration of 8 minutes and ICP/BP ratio of 0.72 +/- 0.13. The difference in the erectile response between groups of animals treated with NO or sialorphin nanoparticles was significantly different from the control group treated with empty nanoparticles (P < 0.05) Tadalafil nanoparticles showed a significant increase in the mean ICP/BP (0.737 +/- 0.029) following stimulation of the cavernous nerve (4 mA) 1 hour after application of the nanoparticles with a visibly improved erectile response. Nanoparticles encapsulating three different erectogenic agents resulted in increased erectile function when applied to the penis of a rat model of ED. Nanoparticles represent a potential novel route for topical delivery of erectogenic agents which could improve the safety profile for existing orally administered drugs by avoiding effects of absorption and first-pass metabolism, and would be less hazardous than injection.

Inorganic/organic nanocomposites: Reaching a high filler content without increasing viscosity using core-shell structured nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benhadjala, W., E-mail: warda.benhadjala@cea.fr; CEA, LETI, Minatec Campus, 38000 Grenoble; Gravoueille, M.

2015-11-23

Extensive research is being conducted on the development of inorganic/organic nanocomposites for a wide variety of applications in microelectronics, biotechnologies, photonics, adhesives, or optical coatings. High filler contents are usually required to fully optimize the nanocomposites properties. However, numerous studies demonstrated that traditional composite viscosity increases with increasing the filler concentration reducing therefore significantly the material processability. In this work, we synthesized inorganic/organic core-shell nanocomposites with different shell thicknesses. By reducing the shell thickness while maintaining a constant core size, the nanoparticle molecular mass decreases but the nanocomposite filler fraction is correlatively increased. We performed viscosity measurements, which clearly highlightedmore » that intrinsic viscosity of hybrid nanoparticles decreases as the molecular mass decreases, and thus, as the filler fraction increases, as opposed to Einstein predictions about the viscosity of traditional inorganic/polymer two-phase mixtures. This exceptional behavior, modeled by Mark-Houwink-Sakurada equation, proves to be a significant breakthrough for the development of industrializable nanocomposites with high filler contents.« less

Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.

PubMed

Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

2014-01-01

The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined.

Influence of nanoparticles on color stability, microhardness, and flexural strength of acrylic resins specific for ocular prosthesis.

PubMed

Andreotti, Agda Marobo; Goiato, Marcelo Coelho; Moreno, Amália; Nobrega, Adhara Smith; Pesqueira, Aldiéris Alves; dos Santos, Daniela Micheline

2014-01-01

The aim of this study was to assess the effect of adding nanoparticles to N1 acrylic resin intended for artificial sclera, in terms of the color stability, microhardness, and flexural strength of the resin. Three hundred samples of N1 acrylic resin were used: 100 samples for color stability and microhardness tests (each test was performed on the opposite side of each sample), and 200 samples for flexural strength testing (100 samples before and after 1,008 hours of accelerated aging). Samples for each test were separated into ten groups (n=10), ie, without nanoparticles (control group) or with nanoparticles of zinc oxide, titanium dioxide (TiO₂), and barium sulfate at weight concentrations of 1%, 2%, and 2.5% (nanoparticle groups). Data were subjected to statistical analysis with nested analysis of variance and Tukey's test (P<0.05 significance level). Among the nanoparticle groups, the TiO₂ groups showed better color stability at all concentrations. Microhardness values increased after artificial aging, except for the control and zinc oxide groups. After aging, the 1%-2% TiO₂ groups had significantly higher microhardness values compared with the other nanoparticle groups. Before aging, there was a significant difference in flexural strength between the control and nanoparticle groups. After aging, the control and TiO₂ groups, regardless of concentration, showed the lowest flexural strength values. Incorporation of nanoparticles directly influenced the acrylic resin properties, with TiO₂ being the most influential nanoparticle in terms of the evaluated properties.

Enhancing Nanoparticle Accumulation and Retention in Desmoplastic Tumors via Vascular Disruption for Internal Radiation Therapy

PubMed Central

Satterlee, Andrew B.; Rojas, Juan D.; Dayton, Paul A.; Huang, Leaf

2017-01-01

Aggressive, desmoplastic tumors are notoriously difficult to treat because of their extensive stroma, high interstitial pressure, and resistant tumor microenvironment. We have developed a combination therapy that can significantly slow the growth of large, stroma-rich tumors by causing massive apoptosis in the tumor center while simultaneously increasing nanoparticle uptake through a treatment-induced increase in the accumulation and retention of nanoparticles in the tumor. The vascular disrupting agent Combretastatin A-4 Phosphate (CA4P) is able to increase the accumulation of radiation-containing nanoparticles for internal radiation therapy, and the retention of these delivered radioisotopes is maintained over several days. We use ultrasound to measure the effect of CA4P in live tumor-bearing mice, and we encapsulate the radio-theranostic isotope 177Lutetium as a therapeutic agent as well as a means to measure nanoparticle accumulation and retention in the tumor. This combination therapy induces prolonged apoptosis in the tumor, decreasing both the fibroblast and total cell density and allowing further tumor growth inhibition using a cisplatin-containing nanoparticle. PMID:28042332

Small-Angle Neutron Scattering Study of Interplay of Attractive and Repulsive Interactions in Nanoparticle-Polymer System.

PubMed

Kumar, Sugam; Aswal, Vinod K; Kohlbrecher, Joachim

2016-02-16

The phase behavior of nanoparticle (silica)-polymer (polyethylene glycol) system without and with an electrolyte (NaCl) has been studied. It is observed that nanoparticle-polymer system behaves very differently in the presence of electrolyte. In the absence of electrolyte, the nanoparticle-polymer system remains in one-phase even at very high polymer concentrations. On the other hand, a re-entrant phase behavior is found in the presence of electrolyte, where one-phase (individual) system undergoes two-phase (nanoparticle aggregation) and then back to one-phase with increasing polymer concentration. The regime of two-phase system has been tuned by varying the electrolyte concentration. The polymer concentration range over which the two-phase system exists is significantly enhanced with the increase in the electrolyte concentration. These systems have been characterized by small-angle neutron scattering (SANS) experiments of contrast-marching the polymer to the solvent. The data are modeled using a two-Yukawa potential accounting for both attractive and repulsive parts of the interaction between nanoparticles. The phase behavior of nanoparticle-polymer system is explained by interplay of attractive (polymer-induced attractive depletion between nanoparticles) and repulsive (nanoparticle-nanoparticle electrostatic repulsion and polymer-polymer repulsion) interactions present in the system. In the absence of electrolyte, the strong electrostatic repulsion between nanoparticles dominates over the polymer-induced depletion attraction and the nanoparticle system remains in one-phase. With addition of electrolyte, depletion attraction overcomes electrostatic repulsion at some polymer concentration, resulting into nanoparticle aggregation and two-phase system. Further addition of polymer increases the polymer-polymer repulsion which eventually reduces the strength of depletion and hence re-entrant phase behavior. The effects of varying electrolyte concentration on the phase behavior of nanoparticle-polymer system are understood in terms of modifications in nanoparticle-nanoparticle and polymer-polymer interactions. The nanoparticle aggregates in two-phase systems are found to have surface fractal morphology.

Zirconium and silver co-doped TiO2 nanoparticles as visible light catalyst for reduction of 4-nitrophenol, degradation of methyl orange and methylene blue

NASA Astrophysics Data System (ADS)

Naraginti, Saraschandra; Stephen, Finian Bernard; Radhakrishnan, Adhithya; Sivakumar, A.

2015-01-01

Catalytic activity of Zr and Ag co-doped TiO2 nanoparticles on the reduction of 4-nitrophenol, degradation of methylene blue and methyl orange was studied using sodium borohydride as reducing agent. The nanoparticles were characterized using X-ray diffraction, energy dispersive X-ray, high resolution transmission electron microscopy, selected area electron diffraction and UV-Vis spectroscopy. The rate of the reduction/degradation was found to increase with increasing amount of the photocatalyst which could be attributed to higher dispersity and small size of the nanoparticles. The catalytic activity of Zr and Ag co-doped TiO2 nanoparticles showed no significant difference even after recycling the catalyst four times indicating a promising potential for industrial application of the prepared photocatalyst.

Preparation and modification of N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride nanoparticle as a protein carrier.

PubMed

Xu, Yongmei; Du, Yumin; Huang, Ronghua; Gao, Leping

2003-12-01

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) is water-soluble derivative of chitosan (CS), synthesized by the reaction between glycidyl-trimethyl-ammonium chloride and CS. HTCC nanoparticles have been formed based on ionic gelation process of HTCC and sodium tripolyphosphate (TPP). Bovine serum albumin (BSA), as a model protein drug, was incorporated into the HTCC nanoparticles. HTCC nanoparticles were 110-180 nm in size, and their encapsulation efficiency was up to 90%. In vitro release studies showed a burst effect and a slow and continuous release followed. Encapsulation efficiency was obviously increased with increase of initial BSA concentration. Increasing TPP concentration from 0.5 to 0.7 mg/ml promoted encapsulation efficiency from 46.7% to 90%, and delayed release. As for modified HTCC nanoparticles, adding polyethylene glycol (PEG) or sodium alginate obviously decreased the burst effect of BSA from 42% to 18%. Encapsulation efficiency was significantly reduced from 47.6% to 2% with increase of PEG from 1.0 to 20.0 mg/ml. Encapsulation efficiency was increased from 14.5% to 25.4% with increase of alginate from 0.3 to 1.0 mg/ml.

Creation of energetic biothermite inks using ferritin liquid protein

NASA Astrophysics Data System (ADS)

Slocik, Joseph M.; McKenzie, Ruel; Dennis, Patrick B.; Naik, Rajesh R.

2017-04-01

Energetic liquids function mainly as fuels due to low energy densities and slow combustion kinetics. Consequently, these properties can be significantly increased through the addition of metal nanomaterials such as aluminium. Unfortunately, nanoparticle additives are restricted to low mass fractions in liquids because of increased viscosities and severe particle agglomeration. Nanoscale protein ionic liquids represent multifunctional solvent systems that are well suited to overcoming low mass fractions of nanoparticles, producing stable nanoparticle dispersions and simultaneously offering a source of oxidizing agents for combustion of reactive nanomaterials. Here, we use iron oxide-loaded ferritin proteins to create a stable and highly energetic liquid composed of aluminium nanoparticles and ferritin proteins for printing and forming 3D shapes and structures. In total, this bioenergetic liquid exhibits increased energy output and performance, enhanced dispersion and oxidation stability, lower activation temperatures, and greater processability and functionality.

Enhanced infra-red emission from sub-millimeter microelectromechanical systems micro hotplates via inkjet deposited carbon nanoparticles and fullerenes

NASA Astrophysics Data System (ADS)

De Luca, A.; Cole, M. T.; Fasoli, A.; Ali, S. Z.; Udrea, F.; Milne, W. I.

2013-06-01

In this paper, we demonstrate a micro-inkjet printing technique as a reproducible post-process for the deposition of carbon nanoparticles and fullerene adlayers onto fully CMOS compatible micro-electro-mechanical silicon-on-insulator infrared (IR) light sources to enhance their infrared emission. We show experimentally a significant increase in the infrared emission efficiency of the coated emitters. We numerically validate these findings with models suggesting a dominant performance increase for wavelengths <5.5 μm. Here, the bimodal size distribution in the diameter of the carbon nanoparticles, relative to the fullerenes, is an effective mediator towards topologically enhanced emittance of our miniaturised emitters. A 90% improvement in IR emission power density has been shown which we have rationalised with an increase in the mean thickness of the deposited carbon nanoparticle adlayer.

SIKVAV peptide functionalized ultra-small gold nanoparticles for selective targeting of α6β1 integrin in hepatocellular carcinoma

NASA Astrophysics Data System (ADS)

Roskamp, M.; Coulter, T.; Ding, Y.; Perrins, R.; Espinosa Garcia, C.; Pace, A.; Hale, S.; Robinson, A.; Williams, P.; Aguilera Peral, U.; Patel, K.; Palmer, D.

2017-04-01

Ultra-small glycan-passivated gold nanoparticles of <2nm diameter were funtionalised with a short HS-EG(8)-COOH ligand. The nanoparticles were subsequently labelled, in a stoichiometrically controllable manner, with integrin-binding peptide SIKVAV and the maytansinoid cytotoxin DM4. In vitro assays showed significantly increased integrin-mediated uptake of SIKVAV labelled nanoparticles in HepG2 cells. SIKVAV targeted nanoparticle binding was shown to be outcompeted with free SIKVAV peptide, indicating target specific uptake. DM4 was passively attached to nanoparticles via sulfhydryl ligand exchange at the gold nanoparticle surface, which rendered them highly cytotoxic (IC50 ˜1 × 10-9M). In a rat model, pharmacokinetic studies showed that nanoparticle biodistribution was strongly altered by labelling with either peptide and DM4 moieties.

Morphology and Structural Properties of Novel Short Linear Glucan/Protein Hybrid Nanoparticles and Their Influence on the Rheological Properties of Starch Gel.

PubMed

Li, Xiaojing; Ji, Na; Li, Man; Zhang, Shuangling; Xiong, Liu; Sun, Qingjie

2017-09-13

Starch nanoparticles were potential texture modifiers. However, they have strong tendency to aggregate and poor water dispersibility, which limited their application. The interaction between glucan (prepared from starch by enzymatic modification) and protein could significantly improve the dispersity of starch nanoparticles and, thus, enhance the rheological properties of food gels. In this work, glucan/protein hybrid nanoparticles were successfully developed for the first time using short linear glucan (SLG) and edible proteins [soy protein isolate (SPI), rice protein (RP), and whey protein isolate (WPI)]. The results showed that the SLG/SPI hybrid nanoparticles exhibited hollow structures, of which the smallest size was approximately 10-20 nm when the SLG/SPI ratio was 10:5. In contrast, SLG/RP nanoparticles displayed flower-like superstructures, and SLG/WPI nanoparticles presented stacked lamellar nanostructures with a width of 5-10 nm and a length of 50-70 nm. In comparison to bare SLG nanoparticles, SLG/SPI and SLG/WPI hybrid nanoparticles had higher melting temperatures. The addition of all nanoparticles greatly increased the storage modulus of corn starch gels and decreased loss tangent values. Importantly, the G' value of starch gels increased by 567% with the addition of flower-like SLG/RP superstructures.

Thermophysical Properties of Nanoparticle-Enhanced Ionic Liquids (NEILs) Heat-Transfer Fluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.

2013-06-20

An experimental investigation was completed on nanoparticle enhanced ionic liquid heat transfer fluids as an alternative to conventional organic based heat transfer fluids (HTFs). These nanoparticle-based HTFs have the potential to deliver higher thermal conductivity than the base fluid without a significant increase in viscosity at elevated temperatures. The effect of nanoparticle morphology and chemistry on thermophysical properties was examined. Whisker shaped nanomaterials were found to have the largest thermal conductivity temperature dependence and were also less likely to agglomerate in the base fluid than spherical shaped nanomaterials.

Targeted Nanotechnology for Cancer Imaging

PubMed Central

Toy, Randall; Bauer, Lisa; Hoimes, Christopher; Ghaghada, Ketan B.; Karathanasis, Efstathios

2014-01-01

Targeted nanoparticle imaging agents provide many benefits and new opportunities to facilitate accurate diagnosis of cancer and significantly impact patient outcome. Due to the highly engineerable nature of nanotechnology, targeted nanoparticles exhibit significant advantages including increased contrast sensitivity, binding avidity and targeting specificity. Considering the various nanoparticle designs and their adjustable ability to target a specific site and generate detectable signals, nanoparticles can be optimally designed in terms of biophysical interactions (i.e., intravascular and interstitial transport) and biochemical interactions (i.e., targeting avidity towards cancer-related biomarkers) for site-specific detection of very distinct microenvironments. This review seeks to illustrate that the design of a nanoparticle dictates its in vivo journey and targeting of hard-to-reach cancer sites, facilitating early and accurate diagnosis and interrogation of the most aggressive forms of cancer. We will report various targeted nanoparticles for cancer imaging using X-ray computed tomography, ultrasound, magnetic resonance imaging, nuclear imaging and optical imaging. Finally, to realize the full potential of targeted nanotechnology for cancer imaging, we will describe the challenges and opportunities for the clinical translation and widespread adaptation of targeted nanoparticles imaging agents. PMID:25116445

Effect of rutile titania dioxide nanoparticles on the mechanical property, thermal stability, weathering resistance and antibacterial property of styrene acrylic polyurethane coating

NASA Astrophysics Data System (ADS)

Vuong Nguyen, Thien; Nguyen, Tuan Anh; Dao, Phi Hung; Phuc Mac, Van; Hiep Nguyen, Anh; Thanh Do, Minh; Nguyen, The Huu

2016-12-01

This study aims to enhance the mechanical properties, thermal stability, weathering resistance and antibacterial property of a styrene acrylic polyurethane coating by adding rutile titania dioxide (R-TiO2) nanoparticles in coating formulation. The styrene acrylic polyurethane/R-TiO2 nanocomposite had been prepared by using ultrasonication. The effects of nanoparticles on the mechanical properties, thermal stability and weathering resistance of as-prepared coatings were investigated by using the adhesion strength and ball impact tests, the Fourier transform infrared and UV-vis analyses, thermogravimetric analysis (TGA), and UV/condensation weathering chamber equipped with UVA-340 fluorescent lamps, respectively. The disperse quality of nanoparticles in the coating was examined by using the field emission scanning electron microscope (FESEM). The mechanical test results showed that suitable content of R-TiO2 nanoparticles in the nanocomposite coating was 2 wt%. The FESEM images indicated that the nanoparticles were dispersed homogeneously into the entire volume of the coating. For the nanocomposite prepared by 3 h of ultrasonication, the average size of nanoparticles was in range of 40-50 nm. The ball impact and adhesion tests showed that the incorporation of nanoparticles into the coating significantly enhanced the impact strength from 120 to 145 kg cm and increased the adhesion from level 1 to level 0. The TGA test illustrated that in presence of nanoparticles, the decomposition temperature of coating increased from 146.9 °C to 154.21 °C. For the temperature at 50% loss in mass (T 50%), it was found that the T 50% of the neat coating is 351.86 °C. Adding the 2 wt% R-TiO2 nanoparticles into coating increased the T 50% value to 360.06 °C. After UV/condensation accelerated weathering test (30 cycles), the significant improvement in weight loss, impact strength and adhesion of the neat coating was observed with the presence of nanoparticles. The antibacterial test showed that in the nanocomposite coating, R-TiO2 nanoparticles exhibited their photocatalytic effect in the inhibition against E. coli bacterial growth. Incorporating 2 wt% of R-TiO2 nanoparticles into the coating reduced the bacterial concentration by 6.1% after 60 min of culture.

Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

NASA Astrophysics Data System (ADS)

Wada, S.; Mase, Y.; Shimizu, S.; Maeda, K.; Fujii, I.; Nakashima, K.; Pulpan, P.; Miyajima, N.

2011-10-01

Porous potassium niobate (KNbO3, KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

Copper Oxide Nanoparticles Impact Several Toxicological Endpoints and Cause Neurodegeneration in Caenorhabditis elegans

PubMed Central

Zanon, Tyler; Kappell, Anthony D.; Petrella, Lisa N.; Andersen, Erik C.; Hristova, Krassimira R.

2016-01-01

Engineered nanoparticles are becoming increasingly incorporated into technology and consumer products. In 2014, over 300 tons of copper oxide nanoparticles were manufactured in the United States. The increased production of nanoparticles raises concerns regarding the potential introduction into the environment or human exposure. Copper oxide nanoparticles commonly release copper ions into solutions, which contribute to their toxicity. We quantified the inhibitory effects of both copper oxide nanoparticles and copper sulfate on C. elegans toxicological endpoints to elucidate their biological effects. Several toxicological endpoints were analyzed in C. elegans, including nematode reproduction, feeding behavior, and average body length. We examined three wild C. elegans isolates together with the Bristol N2 laboratory strain to explore the influence of different genotypic backgrounds on the physiological response to copper challenge. All strains exhibited greater sensitivity to copper oxide nanoparticles compared to copper sulfate, as indicated by reduction of average body length and feeding behavior. Reproduction was significantly reduced only at the highest copper dose, though still more pronounced with copper oxide nanoparticles compared to copper sulfate treatment. Furthermore, we investigated the effects of copper oxide nanoparticles and copper sulfate on neurons, cells with known vulnerability to heavy metal toxicity. Degeneration of dopaminergic neurons was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, mutants in the divalent-metal transporters, smf-1 or smf-2, showed increased tolerance to copper exposure, implicating both transporters in copper-induced neurodegeneration. These results highlight the complex nature of CuO nanoparticle toxicity, in which a nanoparticle-specific effect was observed in some traits (average body length, feeding behavior) and a copper ion specific effect was observed for other traits (neurodegeneration, response to stress). PMID:27911941

Toxicity of silver nanoparticles in zebrafish models

NASA Astrophysics Data System (ADS)

Asharani, P. V.; Lian Wu, Yi; Gong, Zhiyuan; Valiyaveettil, Suresh

2008-06-01

This study was initiated to enhance our insight on the health and environmental impact of silver nanoparticles (Ag-np). Using starch and bovine serum albumin (BSA) as capping agents, silver nanoparticles were synthesized to study their deleterious effects and distribution pattern in zebrafish embryos (Danio rerio). Toxicological endpoints like mortality, hatching, pericardial edema and heart rate were recorded. A concentration-dependent increase in mortality and hatching delay was observed in Ag-np treated embryos. Additionally, nanoparticle treatments resulted in concentration-dependent toxicity, typified by phenotypes that had abnormal body axes, twisted notochord, slow blood flow, pericardial edema and cardiac arrhythmia. Ag+ ions and stabilizing agents showed no significant defects in developing embryos. Transmission electron microscopy (TEM) of the embryos demonstrated that nanoparticles were distributed in the brain, heart, yolk and blood of embryos as evident from the electron-dispersive x-ray analysis (EDS). Furthermore, the acridine orange staining showed an increased apoptosis in Ag-np treated embryos. These results suggest that silver nanoparticles induce a dose-dependent toxicity in embryos, which hinders normal development.

Fullerene (C60) nanoparticles exert photocytotoxicity through modulation of reactive oxygen species and p38 mitogen-activated protein kinase activation in the MCF-7 cancer cell line

NASA Astrophysics Data System (ADS)

Li, Zhi; Zhang, Fei-long; Wang, Zhiyuan; Pan, Li-li; Shen, Ying-ying; Zhang, Zhen-zhong

2013-12-01

The photocytotoxicity of water-dispersed 100-300 nm fullerene amino acid derivatives nanoparticles was studied. The nanoparticle solution of fullerene derivatives, l-phenylalanine (C60-phe) and glycine (C60-gly), suppressed the in vitro growth of MCF-7 cells lines, induced cancer cells apoptosis, and caused a perturbation of the cell cycle. These nanoparticle solutions increased intracellular reactive oxygen species after irradiation. C60-phe or C60-gly upregulated the expression of phosphorylated (p)p38 mitogen-activated protein kinase (MAPK). N-Acetyl- l-cysteine significantly depressed the composite-induced activation of p38MAPK, and the kinase inhibitor SB203580 significantly prevented C60 derivative-induced cell apoptosis. This study revealed that p38MAPK is activated by C60 nanoparticles through triggering reactive oxygen species generation, leading to cancer cell injuries.

DNA-encapsulated magnesium phosphate nanoparticles elicit both humoral and cellular immune responses in mice

PubMed Central

Bhakta, Gajadhar; Nurcombe, Victor; Maitra, Amarnath; Shrivastava, Anju

2014-01-01

The efficacy of pEGFP (plasmid expressing enhanced green fluorescent protein)-encapsulated PEGylated (meaning polyethylene glycol coated) magnesium phosphate nanoparticles (referred to as MgPi-pEGFP nanoparticles) for the induction of immune responses was investigated in a mouse model. MgPi-pEGFP nanoparticles induced enhanced serum antibody and antigen-specific T-lymphocyte responses, as well as increased IFN-? and IL-12 levels compared to naked pEGFP when administered via intravenous, intraperitoneal or intramuscular routes. A significant macrophage response, both in size and activity, was also observed when mice were immunized with the nanoparticle formulation. The response was highly specific for the antigen, as the increase in interaction between macrophages and lymphocytes as well as lymphocyte proliferation took place only when they were re-stimulated with recombinant green fluorescence protein (rGFP). Thus the nanoparticle formulation elicited both humoral as well as cellular responses. Cytokine profiling revealed the induction of Th-1 type responses. The results suggest DNA-encapsulated magnesium phosphate (MgPi) nanoparticles may constitute a safer, more stable and cost-efficient DNA vaccine formulation. PMID:24936399

Formation of Ge nanoparticles in SiO xN y by ion implantation and thermal annealing

DOE PAGES

Mirzaei, Sahar; Kremer, F.; Sprouster, D. J.; ...

2015-10-20

Germanium nanoparticles embedded within dielectric matrices hold much promise for applications in optoelectronic and electronic devices. Here we investigate the formation of Ge nanoparticles in amorphous SiO 1.67N 0.14 as a function of implanted atom concentration and thermal annealing temperature. Using x-ray absorption spectroscopy and other complementary techniques, we show Ge nanoparticles exhibit significant finite-size effects such that the coordination number decreases and structural disorder increases as the nanoparticle size decreases. While the composition of SiO 1.67N 0.14 is close to that of SiO 2, we demonstrate that the addition of this small fraction of N yields a much reducedmore » nanoparticle size relative to those formed in SiO 2 under comparable implantation and annealing conditions. We attribute this difference to an increase in an atomic density and a much reduced diffusivity of Ge in the oxynitride matrix. Finally, these results demonstrate the potential for tailoring Ge nanoparticle sizes and structural properties in the SiO xN y matrices by controlling the oxynitride stoichiometry.« less

pH-responsive thiolated chitosan nanoparticles for oral low-molecular weight heparin delivery: in vitro and in vivo evaluation.

PubMed

Fan, Bo; Xing, Yang; Zheng, Ying; Sun, Chuan; Liang, Guixian

2016-01-01

The aim of present study was to investigate a pH-responsive and mucoadhesive nanoparticle system for oral bioavailability enhancement of low-molecular weight heparin (LMWH). The thioglycolic acid (TGA) was first covalently attached to chitosan (CS) with 396.97 ± 54.54 μmol thiol groups per gram of polymer and then the nanoparticles were prepared with thiolated chitosan (TCS) and pH-sensitive polymer hydroxypropyl methylcellulose phthalate (HPMCP) by ionic cross-linking method. The obtained nanoparticles were characterized for the shape, particle size, zeta potential, drug entrapment efficiency and loading capacity. In vitro results revealed the acid stability of pH-responsive nanoparticles, which had a significant control over LMWH release and could effectively protect entrapped drugs in simulated gastric conditions. By the attachment of the thiol ligand, an improvement of permeation-enhancing effect on freshly excised carp intestine (1.86-fold improvement) could be found. The mucoadhesive properties were evaluated using fluorescently labeled TCS or CS nanoparticles. As compared with the controls, a significant improvement of mucoadhesion on rat intestinal mucosa was observed in TCS/HPMCP nanoparticles via confocal laser scanning microscopy. The activated partial thromboplastin time (APTT) was significantly prolonged and an increase in the oral bioavailability of LMWH was turned out to be pronounced after oral delivered LMWH-loaded TCS/HPMCP nanoparticles in rats, which suggested enhanced anticoagulant effects and improved absorption of LMWH. In conclusion, pH-responsive TCS/HPMCP nanoparticles hold promise for oral delivery of LMWH.

Expression of circadian gens in different rat tissues is sensitive marker of in vivo silver nanoparticles action

NASA Astrophysics Data System (ADS)

Minchenko, D. O.; Yavorovsky, O. P.; Zinchenko, T. O.; Komisarenko, S. V.; Minchenko, O. H.

2012-09-01

Circadian factors PER1, PER2, ARNTL and CLOCK are important molecular components of biological clock system and play a fundamental role in the metabolism at both the behavioral and molecular levels and potentially have great importance for understanding metabolic health and disease, because disturbance the circadian processes lead to developing of different pathology. The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronics, home products, and for water disinfection, but little is yet known about their toxicity. These nanoparticles induce blood-brain barrier destruction, astrocyte swelling, cause degeneration of neurons and impair neurodevelopment as well as embryonic development. We studied the expression of genes encoded the key molecular components of circadian clock system in different rat organs after intratracheally instilled silver nanoparticles which quite rapidly translocate from the lungs into the blood stream and accumulate in different tissues. We have shown that silver nanoparticles significantly affect the expression levels of PER1, PER2, ARNTL and CLOCK mRNA in different rat tissues in time-dependent and tissue-specific manner. High level of PER1, ARNTL and CLOCK mRNA expression was observed in the lung on the 1st 3rd and 14th day after treatment of rats with silver nanoparticles. At the same time, the expression level of PER1 mRNA in the brain and liver increases predominantly on the 1st and 14th day but decreases in the testis. Significant increase of the expression level of PER2 and ARNTL mRNA was detected only in the brain of treated by silver nanoparticles rats. Besides that, intratracheally instilled silver nanoparticles significantly reduced the expression levels of CLOCK mRNA in the brain, heart and kidney. No significant changes in the expression level of PER2 mRNA were found in the lung, liver, heart and testis, except kidney where this mRNA expression decreases on the 3rd and 14th day after treatment of rats with silver nanoparticles. It was also shown that expression level of PFKFB4, a key enzyme of glycolysis regulation, gradually reduces in the brain from 1st to 14th day being up to 4 fold less on 14th day after treatment of animals with silver nanoparticles. Thus, the intratracheally instilled silver nanoparticles significantly affect the expression of PER1, PER2, ARNTL, and CLOCK genes which are an important molecular component of circadian clock system. This is because a disruption of the circadian processes leads to a development of various pathologic processes. The results of this study clearly demonstrate that circadian genes could be a sensitive test for detection of silver nanoparticles toxic action and suggest that more caution is needed in biomedical applications of silver nanoparticles as well as higher level of safety in silver nanoparticles production industry.

Au-nanoparticles grafted on plasma treated PE

NASA Astrophysics Data System (ADS)

Švorčík, V.; Chaloupka, A.; Řezanka, P.; Slepička, P.; Kolská, Z.; Kasálková, N.; Hubáček, T.; Siegel, J.

2010-03-01

Polyethylene (PE) surface was treated with Ar plasma. Activated surface was grafted from methanol solution of 1,2-ethanedithiol. Then the sample was immersed into freshly prepared colloid solution of Au-nanoparticles. Finally Au layer was sputtered on the samples. Properties of the modified PE were studied using various methods: AFM, EPR, RBS and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain (AFM) and creation of free radicals by EPR. After grafting with dithiol, the concentration of free radicals declines. The presence of Au and S in the surface layer after the coating with Au-nanoparticles was proved by RBS. Plasma treatment changes PE surface morphology and increases surface roughness, too. Another significant change in surface morphology and roughness was observed after deposition of Au-nanoparticles. Nanoindentation measurements show that the grafting with Au-nanoparticles increases adhesion of subsequently sputtered Au layer.

Nanoparticle-induced unusual melting and solidification behaviours of metals

PubMed Central

Ma, Chao; Chen, Lianyi; Cao, Chezheng; Li, Xiaochun

2017-01-01

Effective control of melting and solidification behaviours of materials is significant for numerous applications. It has been a long-standing challenge to increase the melted zone (MZ) depth while shrinking the heat-affected zone (HAZ) size during local melting and solidification of materials. In this paper, nanoparticle-induced unusual melting and solidification behaviours of metals are reported that effectively solve this long-time dilemma. By introduction of Al2O3 nanoparticles, the MZ depth of Ni is increased by 68%, while the corresponding HAZ size is decreased by 67% in laser melting at a pulse energy of 0.18 mJ. The addition of SiC nanoparticles shows similar results. The discovery of the unusual melting and solidification of materials that contain nanoparticles will not only have impacts on existing melting and solidification manufacturing processes, such as laser welding and additive manufacturing, but also on other applications such as pharmaceutical processing and energy storage. PMID:28098147

On the self-damping nature of densification in photonic sintering of nanoparticles

PubMed Central

MacNeill, William; Choi, Chang-Ho; Chang, Chih-Hung; Malhotra, Rajiv

2015-01-01

Sintering of nanoparticle inks over large area-substrates is a key enabler for scalable fabrication of patterned and continuous films, with multiple emerging applications. The high speed and ambient condition operation of photonic sintering has elicited significant interest for this purpose. In this work, we experimentally characterize the temperature evolution and densification in photonic sintering of silver nanoparticle inks, as a function of nanoparticle size. It is shown that smaller nanoparticles result in faster densification, with lower temperatures during sintering, as compared to larger nanoparticles. Further, high densification can be achieved even without nanoparticle melting. Electromagnetic Finite Element Analysis of photonic heating is coupled to an analytical sintering model, to examine the role of interparticle neck growth in photonic sintering. It is shown that photonic sintering is an inherently self-damping process, i.e., the progress of densification reduces the magnitude of subsequent photonic heating even before full density is reached. By accounting for this phenomenon, the developed coupled model better captures the experimentally observed sintering temperature and densification as compared to conventional photonic sintering models. Further, this model is used to uncover the reason behind the experimentally observed increase in densification with increasing weight ratio of smaller to larger nanoparticles. PMID:26443492

Exposure of agricultural crops to nanoparticle CeO2 in biochar-amended soil

USDA-ARS?s Scientific Manuscript database

Biochar is seeing increased usage as an amendment in agricultural soils but the significance of nanoscale interactions between this additive and engineered nanoparticles (ENP) remains largely unknown. In the present study, corn (Zea mays), lettuce (Lactuca sativa), soybean (Glycine max) and zucchini...

Spectral Selectivity of Plasmonic Interactions between Individual Up-Converting Nanocrystals and Spherical Gold Nanoparticles.

PubMed

Piątkowski, Dawid; Schmidt, Mikołaj K; Twardowska, Magdalena; Nyk, Marcin; Aizpurua, Javier; Maćkowski, Sebastian

2017-08-04

We experimentally demonstrate strong spectral selectivity of plasmonic interaction that occurs between α-NaYF₄:Er 3+ /Yb 3+ nanocrystals, which feature two emission bands, and spherical gold nanoparticles, with plasmon frequency resonant with one of the emission bands. Spatially-resolved luminescence intensity maps acquired for individual nanocrystals, together with microsecond luminescence lifetime images, show two qualitatively different effects that result from the coupling between plasmon excitations in metallic nanoparticles and emitting states of the nanocrystals. On the one hand, we observe nanocrystals, whose emission intensity is strongly enhanced for both resonant and non-resonant bands with respect to the plasmon resonance. Importantly, this increase is accompanied with shortening of luminescence decays times. In contrast, a significant number of nanocrystals exhibits almost complete quenching of the emission resonant with the plasmon resonance of gold nanoparticles. Theoretical analysis indicates that such an effect can occur for emitters placed at distances of about 5 nm from gold nanoparticles. While under these conditions, both transitions experience significant increases of the radiative emission rates due to the Purcell effect, the non-radiative energy transfer between resonant bands results in strong quenching, which in that situation nullifies the enhancement.

Deposition of gold nano-particles and nano-layers on polyethylene modified by plasma discharge and chemical treatment

NASA Astrophysics Data System (ADS)

Švorčík, V.; Chaloupka, A.; Záruba, K.; Král, V.; Bláhová, O.; Macková, A.; Hnatowicz, V.

2009-08-01

Polyethylene (PE) was treated in Ar plasma discharge and then grafted from methanol solution of 1,2-ethanedithiol to enhance adhesion of gold nano-particles or sputtered gold layers. The modified PE samples were either immersed into freshly prepared colloid solution of Au nano-particles or covered by sputtered, 50 nm thick gold nano-layer. Properties of the plasma modified, dithiol grafted and gold coated PE were studied using XPS, UV-VIS, AFM, EPR, RBS methods and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain, creation of excessive free radicals and conjugated double bonds. After grafting with 1,2-ethanedithiol the concentration of free radicals declined but the concentration of double bonds remained unchanged. Plasma treatment changes PE surface morphology and increases surface roughness too. Another significant change in the surface morphology and roughness was observed after deposition of Au nano-particles. The presence of Au on the sample surface after the coating with Au nano-particles was proved by XPS and RBS methods. Nanoindentation measurements shown that the grafting of plasma activated PE surface with dithiol increases significantly adhesion of sputtered Au nano-layer.

In vivo toxicity, biodistribution, and clearance of glutathione-coated gold nanoparticles.

PubMed

Simpson, Carrie A; Salleng, Kenneth J; Cliffel, David E; Feldheim, Daniel L

2013-02-01

Gold nanoparticles are emerging as promising materials from which to construct nanoscale therapeutics and therapeutic delivery systems. However, animal studies have shown that gold nanoparticles modified with certain thiol monolayers such as tiopronin can cause renal complications and morbidity. Although these effects may be eliminated by coadsorbing small amounts of polyethylene glycol (PEG) onto the nanoparticle surface, PEG can also lower cellular internalization efficiency and binding interactions with protein disease targets, significantly reducing the potential for using gold nanoparticles as therapeutics. Using ICP-MS analysis of blood, urine, and several organs, we show in this article that glutathione-coated gold nanoparticles (1.2 nm ± 0.9 nm) cause no morbidity at any concentration up to and including 60 μM and target primary organs although providing gradual dissipation and clearance over time. This study suggests that glutathione may be an attractive alternative to PEG in the design of gold nanoparticle therapeutics. This study describes the utility and toxicity of glutathione coated gold nanoparticles in comparison to PEGylated counterparts that are commonly used to increase "Stealth" properties and lower cytotoxicity. Too much PEG on the NPs can lead to lower cellular internalization efficiency and less efficient binding interactions with protein disease targets, significantly reducing the potential for using gold nanoparticles as therapeutics. Copyright © 2013 Elsevier Inc. All rights reserved.

Controlled-release of tetracycline and lovastatin by poly(d,l-lactide-co-glycolide acid)-chitosan nanoparticles enhances periodontal regeneration in dogs

PubMed Central

Lee, Bor-Shiunn; Lee, Chien-Chen; Wang, Yi-Ping; Chen, Hsiao-Jan; Lai, Chern-Hsiung; Hsieh, Wan-Ling; Chen, Yi-Wen

2016-01-01

Chronic periodontitis is characterized by inflammation of periodontal tissues, leading to bone resorption and tooth loss. The goal of treatment is to regenerate periodontal tissues including bone and cementum lost as a consequence of disease. The local delivery of tetracycline was proven to be effective in controlling localized periodontal infection without apparent side effects. Previous studies suggested that lovastatin has a significant role in new bone formation; however, the local delivery of lovastatin might enhance its therapeutic effects. A number of local delivery devices have been developed recently, including poly(d,l-lactide-co-glycolide acid) (PLGA) nanoparticles. The aim of this study was to develop a local delivery device, PLGA-lovastatin-chitosan-tetracycline nanoparticles, which allows the sequential release of tetracycline and lovastatin to effectively control local infection and promote bone regeneration in periodontitis. The size and microstructure of nanoparticles were examined by transmission electron microscopy, Nanoparticle Size Analyzer, and Fourier transform infrared spectroscopy. The release of tetracycline and lovastatin was quantified using a UV-Vis spectrophotometer. Furthermore, the cytotoxic effect and alkaline phosphatase activity of the nanoparticles in osteoblast cell cultures as well as antibacterial activity against periodontal pathogens were investigated. Finally, the bone regeneration potential of PLGA nanoparticles in three-walled defects in beagle dogs was investigated. The results indicated that PLGA-lovastatin-chitosan-tetracycline nanoparticles showed good biocompatibility, antibacterial activity, and increased alkaline phosphatase activity. The volumetric analysis from micro-CT revealed significantly increased new bone formation in defects filled with nanoparticles in dogs. This novel local delivery device might be useful as an adjunctive treatment in periodontal regenerative therapy. PMID:26848264

Controlled-release of tetracycline and lovastatin by poly(D,L-lactide-co-glycolide acid)-chitosan nanoparticles enhances periodontal regeneration in dogs.

PubMed

Lee, Bor-Shiunn; Lee, Chien-Chen; Wang, Yi-Ping; Chen, Hsiao-Jan; Lai, Chern-Hsiung; Hsieh, Wan-Ling; Chen, Yi-Wen

2016-01-01

Chronic periodontitis is characterized by inflammation of periodontal tissues, leading to bone resorption and tooth loss. The goal of treatment is to regenerate periodontal tissues including bone and cementum lost as a consequence of disease. The local delivery of tetracycline was proven to be effective in controlling localized periodontal infection without apparent side effects. Previous studies suggested that lovastatin has a significant role in new bone formation; however, the local delivery of lovastatin might enhance its therapeutic effects. A number of local delivery devices have been developed recently, including poly(D,L-lactide-co-glycolide acid) (PLGA) nanoparticles. The aim of this study was to develop a local delivery device, PLGA-lovastatin-chitosan-tetracycline nanoparticles, which allows the sequential release of tetracycline and lovastatin to effectively control local infection and promote bone regeneration in periodontitis. The size and microstructure of nanoparticles were examined by transmission electron microscopy, Nanoparticle Size Analyzer, and Fourier transform infrared spectroscopy. The release of tetracycline and lovastatin was quantified using a UV-Vis spectrophotometer. Furthermore, the cytotoxic effect and alkaline phosphatase activity of the nanoparticles in osteoblast cell cultures as well as antibacterial activity against periodontal pathogens were investigated. Finally, the bone regeneration potential of PLGA nanoparticles in three-walled defects in beagle dogs was investigated. The results indicated that PLGA-lovastatin-chitosan-tetracycline nanoparticles showed good biocompatibility, antibacterial activity, and increased alkaline phosphatase activity. The volumetric analysis from micro-CT revealed significantly increased new bone formation in defects filled with nanoparticles in dogs. This novel local delivery device might be useful as an adjunctive treatment in periodontal regenerative therapy.

Friction factor and heat transfer of nanofluids containing cylindrical nanoparticles in laminar pipe flow

NASA Astrophysics Data System (ADS)

Lin, Jianzhong; Xia, Yi; Ku, Xiaoke

2014-10-01

Numerical simulations of polyalphaolefins-Al2O3 nanofluids containing cylindrical nanoparticles in a laminar pipe flow are performed by solving the Navier-Stokes equation with term of cylindrical nanoparticles, the general dynamic equation for cylindrical nanoparticles, and equation for nanoparticle orientation. The distributions of particle number and volume concentration, the friction factor, and heat transfer are obtained and analyzed. The results show that distributions of nanoparticle number and volume concentration are non-uniform across the section, with larger and smaller values in the region near the pipe center and near the wall, respectively. The non-uniformity becomes significant with the increase in the axial distance from the inlet. The friction factor decreases with increasing Reynolds number. The relationships between the friction factor and the nanoparticle volume concentration as well as particle aspect ratio are dependent on the Reynolds number. The Nusselt number of nanofluids, directly proportional to the Reynolds number, particle volume concentration, and particle aspect ratio, is higher near the pipe entrance than at the downstream locations. The rate of increase in Nusselt number at lower particle volume concentration is more than that at higher concentration. Finally, the expressions of friction factor and Nusselt number as a function of particle volume concentration, particle aspect ratio, and Reynolds number are derived based on the numerical data.

Cell-delivered magnetic nanoparticles caused hyperthermia-mediated increased survival in a murine pancreatic cancer model

PubMed Central

Basel, Matthew T; Balivada, Sivasai; Wang, Hongwang; Shrestha, Tej B; Seo, Gwi Moon; Pyle, Marla; Abayaweera, Gayani; Dani, Raj; Koper, Olga B; Tamura, Masaaki; Chikan, Viktor; Bossmann, Stefan H; Troyer, Deryl L

2012-01-01

Using magnetic nanoparticles to absorb alternating magnetic field energy as a method of generating localized hyperthermia has been shown to be a potential cancer treatment. This report demonstrates a system that uses tumor homing cells to actively carry iron/iron oxide nanoparticles into tumor tissue for alternating magnetic field treatment. Paramagnetic iron/ iron oxide nanoparticles were synthesized and loaded into RAW264.7 cells (mouse monocyte/ macrophage-like cells), which have been shown to be tumor homing cells. A murine model of disseminated peritoneal pancreatic cancer was then generated by intraperitoneal injection of Pan02 cells. After tumor development, monocyte/macrophage-like cells loaded with iron/ iron oxide nanoparticles were injected intraperitoneally and allowed to migrate into the tumor. Three days after injection, mice were exposed to an alternating magnetic field for 20 minutes to cause the cell-delivered nanoparticles to generate heat. This treatment regimen was repeated three times. A survival study demonstrated that this system can significantly increase survival in a murine pancreatic cancer model, with an average post-tumor insertion life expectancy increase of 31%. This system has the potential to become a useful method for specifically and actively delivering nanoparticles for local hyperthermia treatment of cancer. PMID:22287840

Therapeutic gold, silver, and platinum nanoparticles.

PubMed

Yamada, Miko; Foote, Matthew; Prow, Tarl W

2015-01-01

There are an abundance of nanoparticle technologies being developed for use as part of therapeutic strategies. This review focuses on a narrow class of metal nanoparticles that have therapeutic potential that is a consequence of elemental composition and size. The most widely known of these are gold nanoshells that have been developed over the last two decades for photothermal ablation in superficial cancers. The therapeutic effect is the outcome of the thickness and diameter of the gold shell that enables fine tuning of the plasmon resonance. When these metal nanoparticles are exposed to the relevant wavelength of light, their temperature rapidly increases. This in turn induces a localized photothermal ablation that kills the surrounding tumor tissue. Similarly, gold nanoparticles have been developed to enhance radiotherapy. The high-Z nature of gold dramatically increases the photoelectric cross-section. Thus, the photoelectric effects are significantly increased. The outcome of these interactions is enhanced tumor killing with lower doses of radiation, all while sparing tissue without gold nanoparticles. Silver nanoparticles have been used for their wound healing properties in addition to enhancing the tumor-killing effects of anticancer drugs. Finally, platinum nanoparticles are thought to serve as a reservoir for platinum ions that can induce DNA damage in cancer cells. The future is bright with the path to clinical trials is largely cleared for some of the less complex therapeutic metal nanoparticle systems. © 2014 The Authors. WIREs Nanomedicine and Nanobiotechnology published by Wiley Periodicals, Inc.

Protective effects of poly (butyl) cyanoacrylate nanoparticles containing vasoactive intestinal peptide against 6-hydroxydopamine-induced neurotoxicity in vitro.

PubMed

Xu, Zhi-Ran; Wang, Wu-Fang; Liang, Xin-Fang; Liu, Ze-Hua; Liu, Yu; Lin, Liang; Zhu, Xuan

2015-04-01

The present study investigated brain delivery system of vasoactive intestinal peptide (VIP) adsorbed on poly (butyl cyanoacrylate) nanoparticles coated with polysorbate 80 (P80-poly (butyl) cyanoacrylate (PBCA)-nanoparticles (NPs)) and the neuroprotective effects on the formulation in the model of 6-hydroxydopamine (6-OHDA)-induced Parkinsonian dysfunction in the human neuroblastoma cell line SH-SY5Y. Drug-loaded nanoparticles were prepared by emulsion polymerization method using VIP and PBCA and then stirring with polysorbate 80. The resulting nanoparticles possessed high entrapment efficiency and favorable stability against CaCl2 or fetal bovine serum (FBS)-induced aggregation. Use of fluorescein isothiocyanate (FITC)-conjugated polysorbate 80-PBCA nanoparticles in confocal microscopy revealed that nanoparticles are located inside, while the FITC solution could not penetrate into the cells. The blank nanoparticles showed no significant effects on cell viability, indicating that they had no role in protection; however, polysorbate 80-modified VIP-loading PBCA nanoparticles showed enhanced cell viability compared to free VIP in 6-OHDA-mimic cellular model of Parkinson's disease. In addition, the nanoparticles strikingly increased the anti-apoptosis activity and restored the loss of mitochondrial membrane potential (MMP) significantly after the treatment of 6-OHDA. These results demonstrated that the activity of VIP was enhanced by polysorbate 80-PBCA nanoparticles compared to control solutions, suggesting that PBCA nanoparticles coated with polysorbate 80 could be an effective carrier system for VIP.

Nanoparticle distribution during systemic inflammation is size-dependent and organ-specific

NASA Astrophysics Data System (ADS)

Chen, K.-H.; Lundy, D. J.; Toh, E. K.-W.; Chen, C.-H.; Shih, C.; Chen, P.; Chang, H.-C.; Lai, J. J.; Stayton, P. S.; Hoffman, A. S.; Hsieh, P. C.-H.

2015-09-01

This study comprehensively investigates the changing biodistribution of fluorescent-labelled polystyrene latex bead nanoparticles in a mouse model of inflammation. Since inflammation alters systemic circulatory properties, increases vessel permeability and modulates the immune system, we theorised that systemic inflammation would alter nanoparticle distribution within the body. This has implications for prospective nanocarrier-based therapies targeting inflammatory diseases. Low dose lipopolysaccharide (LPS), a bacterial endotoxin, was used to induce an inflammatory response, and 20 nm, 100 nm or 500 nm polystyrene nanoparticles were administered after 16 hours. HPLC analysis was used to accurately quantify nanoparticle retention by each vital organ, and tissue sections revealed the precise locations of nanoparticle deposition within key tissues. During inflammation, nanoparticles of all sizes redistributed, particularly to the marginal zones of the spleen. We found that LPS-induced inflammation induces splenic macrophage polarisation and alters leukocyte uptake of nanoparticles, with size-dependent effects. In addition, spleen vasculature becomes significantly more permeable following LPS treatment. We conclude that systemic inflammation affects nanoparticle distribution by multiple mechanisms, in a size dependent manner.This study comprehensively investigates the changing biodistribution of fluorescent-labelled polystyrene latex bead nanoparticles in a mouse model of inflammation. Since inflammation alters systemic circulatory properties, increases vessel permeability and modulates the immune system, we theorised that systemic inflammation would alter nanoparticle distribution within the body. This has implications for prospective nanocarrier-based therapies targeting inflammatory diseases. Low dose lipopolysaccharide (LPS), a bacterial endotoxin, was used to induce an inflammatory response, and 20 nm, 100 nm or 500 nm polystyrene nanoparticles were administered after 16 hours. HPLC analysis was used to accurately quantify nanoparticle retention by each vital organ, and tissue sections revealed the precise locations of nanoparticle deposition within key tissues. During inflammation, nanoparticles of all sizes redistributed, particularly to the marginal zones of the spleen. We found that LPS-induced inflammation induces splenic macrophage polarisation and alters leukocyte uptake of nanoparticles, with size-dependent effects. In addition, spleen vasculature becomes significantly more permeable following LPS treatment. We conclude that systemic inflammation affects nanoparticle distribution by multiple mechanisms, in a size dependent manner. Electronic supplementary information (ESI) available: IF images of brain, heart, low magnification images of spleen, mouse heart rate and blood pressure post-LPS. See DOI: 10.1039/c5nr03626g

Investigation on hemolytic effect of poly(lactic co-glycolic) acid nanoparticles synthesized using continuous flow and batch processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libi, Sumit; Calenic, Bogdan; Astete, Carlos E.

Abstract With the increasing interest in polymeric nanoparticles for biomedical applications, there is a need for continuous flow methodologies that allow for the precise control of nanoparticle synthesis. Poly(lactide-co-glycolic) acid (PLGA) nanoparticles with diameters of 220–250 nm were synthesized using a lab-on-a-chip, exploiting the precise flow control offered by a millifluidic platform. The association and the effect of PLGA nanoparticles on red blood cells (RBCs) were compared for fluorescent PLGA nanoparticles made by this novel continuous flow process using a millifluidic chip and smaller PLGA nanoparticles made by a batch method. Results indicated that all PLGA nanoparticles studied, independent ofmore » the synthesis method and size, adhered to the surface of RBCs but had no significant hemolytic effect at concentrations lower than 10 mg/ml.« less

Creation of energetic biothermite inks using ferritin liquid protein

PubMed Central

Slocik, Joseph M.; McKenzie, Ruel; Dennis, Patrick B.; Naik, Rajesh R.

2017-01-01

Energetic liquids function mainly as fuels due to low energy densities and slow combustion kinetics. Consequently, these properties can be significantly increased through the addition of metal nanomaterials such as aluminium. Unfortunately, nanoparticle additives are restricted to low mass fractions in liquids because of increased viscosities and severe particle agglomeration. Nanoscale protein ionic liquids represent multifunctional solvent systems that are well suited to overcoming low mass fractions of nanoparticles, producing stable nanoparticle dispersions and simultaneously offering a source of oxidizing agents for combustion of reactive nanomaterials. Here, we use iron oxide-loaded ferritin proteins to create a stable and highly energetic liquid composed of aluminium nanoparticles and ferritin proteins for printing and forming 3D shapes and structures. In total, this bioenergetic liquid exhibits increased energy output and performance, enhanced dispersion and oxidation stability, lower activation temperatures, and greater processability and functionality. PMID:28447665

In Vitro Selective Anti-Proliferative Effect of Zinc Oxide Nanoparticles Against Co-Cultured C2C12 Myoblastoma Cancer and 3T3-L1 Normal Cells.

PubMed

Chandrasekaran, Murugesan; Pandurangan, Muthuraman

2016-07-01

The zinc oxide (ZnO) nanoparticle has been widely used in biomedical applications and cancer therapy and has been reported to induce a selective cytotoxic effect on cancer cell proliferation. The present study investigated the cytotoxicity of ZnO nanoparticles against co-cultured C2C12 myoblastoma cancer cells and 3T3-L1 adipocytes. Our results showed that the ZnO nanoparticles could be cytotoxic to C2C12 myoblastoma cancer cells than 3T3-L1 cells. The messenger RNA (mRNA) expressions of p53 and bax were significantly increased 114.3 and 118.2 % in the C2C12 cells, whereas 42.5 and 40 % were increased in 3T3-L1 cells, respectively. The mRNA expression of bcl-2 was reduced 38.2 and 28.5 % in the C2C12 and 3T3-L1 cells, respectively, whereas the mRNA expression of caspase-3 was increased 80.7 and 51.6 % in the C2C12 and 3T3-L1 cells, respectively. The protein expressions of p53, bax, and caspase-3 were significantly increased 40, 81.8, and 80 % in C2C12 cells, whereas 20.3, 28.2, and 37.9 % were increased in 3T3-L1 cells, respectively. The mRNA expression of bcl-2 was significantly reduced 32.2 and 22.7 % in C2C12 and 3T3-L1 cells, respectively. Caspase-3 enzyme activity and reactive oxygen species (ROS) were increased in co-cultured C2C12 cells compared to 3T3-L1 cells. Taking all these data together, it may suggest that ZnO nanoparticles severely induce apoptosis in C2C12 myoblastoma cancer cells than 3T3-L1 cells.

Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs.

PubMed

Dumkova, Jana; Vrlikova, Lucie; Vecera, Zbynek; Putnova, Barbora; Docekal, Bohumil; Mikuska, Pavel; Fictum, Petr; Hampl, Ales; Buchtova, Marcela

2016-06-03

The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level.

Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs

PubMed Central

Dumkova, Jana; Vrlikova, Lucie; Vecera, Zbynek; Putnova, Barbora; Docekal, Bohumil; Mikuska, Pavel; Fictum, Petr; Hampl, Ales; Buchtova, Marcela

2016-01-01

The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level. PMID:27271611

The influence of dissolved and surface-bound humic acid on the toxicity of TiO₂ nanoparticles to Chlorella sp.

PubMed

Lin, Daohui; Ji, Jing; Long, Zhifeng; Yang, Kun; Wu, Fengchang

2012-09-15

NOM is likely to coat TiO₂ nanoparticles (nano-TiO₂) discharged into the aquatic environment and influence the nanotoxicity to aquatic organisms, which however has not been well investigated. This study explored the influence of nanoparticle surface-bound humic acid (HA, as a model NOM) as well as dissolved HA on the toxicity of nano-TiO₂ to Chlorella sp., with a specific focus on adhesion of the nanoparticles to the algae. Results showed that nano-TiO₂ and the dissolved HA could inhibit the algal growth with an IC₅₀ of 4.9 and 8.4 mg L⁻¹, respectively, while both dissolved and nanoparticle surface-bound HA could significantly alleviate the algal toxicity of nano-TiO₂. IC₅₀ of nano-TiO₂ increased to 18 mg L⁻¹ in the presence of 5 mg L⁻¹ of the dissolved HA and to 48 mg L⁻¹ as the result of surface-saturation by HA. Co-precipitation experiment and transmission electron microscopy observation revealed that both dissolved and nanoparticle surface-bound HA prevented the adhesion of nano-TiO₂ to the algal cells due to the increased electrosteric repulsion. The generation of intracellular reactive oxygen species (ROS) was significantly limited by the dissolved and nanoparticle surface-bound HA. The prevention of adhesion and inhibition of ROS generation could account for the HA-mitigated nanotoxicity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Silica-coated magnetic nanoparticles impair proteasome activity and increase the formation of cytoplasmic inclusion bodies in vitro

PubMed Central

Phukan, Geetika; Shin, Tae Hwan; Shim, Jeom Soon; Paik, Man Jeong; Lee, Jin-Kyu; Choi, Sangdun; Kim, Yong Man; Kang, Seong Ho; Kim, Hyung Sik; Kang, Yup; Lee, Soo Hwan; Mouradian, M. Maral; Lee, Gwang

2016-01-01

The potential toxicity of nanoparticles, particularly to neurons, is a major concern. In this study, we assessed the cytotoxicity of silica-coated magnetic nanoparticles containing rhodamine B isothiocyanate dye (MNPs@SiO2(RITC)) in HEK293 cells, SH-SY5Y cells, and rat primary cortical and dopaminergic neurons. In cells treated with 1.0 μg/μl MNPs@SiO2(RITC), the expression of several genes related to the proteasome pathway was altered, and proteasome activity was significantly reduced, compared with control and with 0.1 μg/μl MNPs@SiO2(RITC)-treated cells. Due to the reduction of proteasome activity, formation of cytoplasmic inclusions increased significantly in HEK293 cells over-expressing the α–synuclein interacting protein synphilin-1 as well as in primary cortical and dopaminergic neurons. Primary neurons, particularly dopaminergic neurons, were more vulnerable to MNPs@SiO2(RITC) than SH-SY5Y cells. Cellular polyamines, which are associated with protein aggregation, were significantly altered in SH-SY5Y cells treated with MNPs@SiO2(RITC). These findings highlight the mechanisms of neurotoxicity incurred by nanoparticles. PMID:27378605

Changes in silver nanoparticles exposed to human synthetic stomach fluid: Effectsof particle size and surface chemistry

EPA Science Inventory

The significant rise in consumer products and applications utilizing the antibacterial properties of silver nanoparticles (AgNPs) has increased the possibility of human exposure. The mobility and bioavailability of AgNPs through the ingestion pathway will depend, in part, on prop...

Pretargeting with bispecific fusion proteins facilitates delivery of nanoparticles to tumor cells with distinct surface antigens.

PubMed

Yang, Qi; Parker, Christina L; Lin, Yukang; Press, Oliver W; Park, Steven I; Lai, Samuel K

2017-06-10

Tumor heterogeneity, which describes the genetically and phenotypically distinct subpopulations of tumor cells present within the same tumor or patient, presents a major challenge to targeted delivery of diagnostic and/or therapeutic agents. An ideal targeting strategy should deliver a given nanocarrier to the full diversity of cancer cells, which is difficult to achieve with conventional ligand-conjugated nanoparticles. We evaluated pretargeting (i.e., multistep targeting) as a strategy to facilitate nanoparticle delivery to multiple target cells by measuring the uptake of biotinylated nanoparticles by lymphoma cells with distinct surface antigens pretreated with different bispecific streptavidin-scFv fusion proteins. Fusion proteins targeting CD20 or tumor-associated glycoprotein 72 (TAG-72) mediated the specific in vitro uptake of 100nm biotin-functionalized nanoparticles by Raji and Jurkat lymphoma cells (CD20-positive and TAG-72-positive cells, respectively). Greater uptake was observed for pretargeted nanoparticles with increasing amounts of surface biotin, with 6- to 18-fold higher uptake vs. non-biotinylated nanoparticle and fusion protein controls. Fully biotin-modified particles remained resistant to cultured macrophage cell uptake, although they were still quickly cleared from systemic circulation in vivo (t 1/2 <1h). For single Raji tumor-bearing mice, pretargeting with CD20-specific FP significantly increased nanoparticle tumor targeting. In mice bearing both Raji and Jurkat tumors, pretargeting with both fusion proteins markedly increased nanoparticle targeting to both tumor types, compared to animals dosed with nanoparticles alone. These in vitro and in vivo observations support further evaluations of pretargeting fusion protein cocktails as a strategy to enhance nanoparticle delivery to a diverse array of molecularly distinct target cells. Copyright © 2017 Elsevier B.V. All rights reserved.

An alternative approach to studying the effects of ZnO nanoparticles in cultured human lymphocytes: combining electrochemistry and genotoxicity tests.

PubMed

Branica, Gina; Mladinić, Marin; Omanović, Dario; Želježić, Davor

2016-12-01

Nanoparticle use has increased radically raising concern about possible adverse effects in humans. Zinc oxide nanoparticles (ZnO NPs) are among the most common nanomaterials in consumer and medical products. Several studies indicate problems with their safe use. The aim of our study was to see at which levels ZnO NPs start to produce adverse cytogenetic effects in human lymphocytes as an early attempt toward establishing safety limits for ZnO NP exposure in humans. We assessed the genotoxic effects of low ZnO NP concentrations (1.0, 2.5, 5, and 7.5 μg mL-1) in lymphocyte cultures over 14 days of exposure. We also tested whether low and high-density lymphocytes differed in their ability to accumulate ZnO NPs in these experimental conditions. Primary DNA damage (measured with the alkaline comet assay) increased with nanoparticle concentration in unseparated and high density lymphocytes. The same happened with the fragmentation of TP53 (measured with the comet-FISH). Nanoparticle accumulation was significant only with the two highest concentrations, regardless of lymphocyte density. High-density lymphocytes had significantly more intracellular Zn2+ than light-density ones. Our results suggest that exposure to ZnO NPs in concentrations above 5 μg mL-1 increases cytogenetic damage and intracellular Zn2+ levels in lymphocytes.

Fungus-mediated synthesis of silver nanoparticles and their activity against pathogenic fungi in combination with fluconazole.

PubMed

Gajbhiye, Monali; Kesharwani, Jayendra; Ingle, Avinash; Gade, Aniket; Rai, Mahendra

2009-12-01

Silver nanoparticles (Ag-NPs) are known to have inhibitory and bactericidal effects. Resistance of fungal infections has emerged in recent years and is a major health problem. Here, we report the extracellular biosynthesis of Ag-NPs using a common fungus, Alternaria alternata. Also in this study, these nanoparticles were evaluated for their part in increasing the antifungal activity of fluconazole against Phoma glomerata, Phoma herbarum, Fusarium semitectum, Trichoderma sp., and Candida albicans. The antifungal activity of fluconazole was enhanced against the test fungi in the presence of Ag-NPs. Fluconazole in combination with Ag-NPs showed the maximum inhibition against C. albicans, which was confirmed from the increase in fold area of inhibition, followed by P. glomerata and Trichoderma sp., which showed less increase in the fold area, whereas no significant enhancement of activity was found against P. herbarum and F. semitectum. The antifungal activity of fluconazole was enhanced in presence of silver nanoparticles against the test fungi. Fluconazole in combination with Ag-NPs showed the maximum inhibition against C. albicans, followed by P. glomerata and Trichoderma sp. No significant enhancement of activity was found against P. herbarum and F. semitectum.

Laminar convective heat transfer of non-Newtonian nanofluids with constant wall temperature

NASA Astrophysics Data System (ADS)

Hojjat, M.; Etemad, S. Gh.; Bagheri, R.; Thibault, J.

2011-02-01

Nanofluids are obtained by dispersing homogeneously nanoparticles into a base fluid. Nanofluids often exhibit higher heat transfer rate in comparison with the base fluid. In the present study, forced convection heat transfer under laminar flow conditions was investigated experimentally for three types of non-Newtonian nanofluids in a circular tube with constant wall temperature. CMC solution was used as the base fluid and γ-Al2O3, TiO2 and CuO nanoparticles were homogeneously dispersed to create nanodispersions of different concentrations. Nanofluids as well as the base fluid show shear thinning (pseudoplastic) rheological behavior. Results show that the presence of nanoparticles increases the convective heat transfer of the nanodispersions in comparison with the base fluid. The convective heat transfer enhancement is more significant when both the Peclet number and the nanoparticle concentration are increased. The increase in convective heat transfer is higher than the increase caused by the augmentation of the effective thermal conductivity.

Effects of polymer-nanoparticle interactions on the viscosity of unentangled polymers under extreme nanoconfinement during capillary rise infiltration.

PubMed

Hor, Jyo Lyn; Wang, Haonan; Fakhraai, Zahra; Lee, Daeyeon

2018-03-28

We explore the effect of confinement and polymer-nanoparticle interactions on the viscosity of unentangled polymers undergoing capillary rise infiltration (CaRI) in dense packings of nanoparticles. In CaRI, a polymer is thermally induced to wick into the dense packings of nanoparticles, leading to the formation of polymer-infiltrated nanoparticle films, a new class of thin film nanocomposites with extremely high concentrations of nanoparticles. To understand the effect of this extreme nanoconfinement, as well as polymer-nanoparticle interactions on the polymer viscosity in CaRI films, we use two polymers that are known to have very different interactions with SiO2 nanoparticles. Using in situ spectroscopic ellipsometry, we monitor the polymer infiltration process, from which we infer the polymer viscosity based on the Lucas-Washburn model. Our results suggest that physical confinement increases the viscosity by approximately two orders of magnitude. Furthermore, confinement also increases the glass transition temperature of both polymers. Thus, under extreme nanoconfinement, the physical confinement has a more significant impact than the polymer-nanoparticle interactions on the viscosity of unentangled polymers, measured through infiltration dynamics, as well as the glass transition temperature. These findings will provide fundamental frameworks for designing processes to enable the fabrication of CaRI nanocomposite films with a wide range of nanoparticles and polymers.

Effect of nanoparticles dispersion on viscoelastic properties of epoxy–zirconia polymer nanocomposites

NASA Astrophysics Data System (ADS)

Singh, Sushil Kumar; Kumar, Abhishek; Jain, Anuj

2018-03-01

In the present work zirconia-nanoparticles were dispersed in epoxy matrix to form epoxy-zirconia polymer nanocomposites using ultrasonication and viscoelastic properties of nanocomposites were investigated. For the same spherical zirconia-nanoparticles (45 nm) were dispersed in weight fraction of 2, 4, 6 and 8 % to reinforce the epoxy. DMA results show the significant enhancement in viscoelastic properties with the dispersion of zirconia nanoparticles in the epoxy matrix. The value of storage modulus and glass transition temperature increases from 179 MPa (pristine) to 225 MPa (6 wt.% ZrO2) and 61 °C (pristine) to 70 °C (6 wt.% ZrO2) respectively with the dispersion of zirconia nanoparticles in the epoxy.

Effect of nanoparticles dispersion on viscoelastic properties of epoxy-zirconia polymer nanocomposites

NASA Astrophysics Data System (ADS)

Singh, Sushil Kumar; Kumar, Abhishek; Jain, Anuj

2018-03-01

In the present work zirconia-nanoparticles were dispersed in epoxy matrix to form epoxy-zirconia polymer nanocomposites using ultrasonication and viscoelastic properties of nanocomposites were investigated. For the same spherical zirconia-nanoparticles (45 nm) were dispersed in weight fraction of 2, 4, 6 and 8 % to reinforce the epoxy. DMA results show the significant enhancement in viscoelastic properties with the dispersion of zirconia nanoparticles in the epoxy matrix. The value of storage modulus and glass transition temperature increases from 179 MPa (pristine) to 225 MPa (6 wt.% ZrO2) and 61 °C (pristine) to 70 °C (6 wt.% ZrO2) respectively with the dispersion of zirconia nanoparticles in the epoxy.

The Effect of CuO Nanoparticles on Antimicrobial Effects and Shear Bond Strength of Orthodontic Adhesives

PubMed Central

Toodehzaeim, Mohammad Hossein; Zandi, Hengameh; Meshkani, Hamidreza; Hosseinzadeh Firouzabadi, Azadeh

2018-01-01

Statement of the Problem: Orthodontic appliances facilitate microbial plaque accumulation and increase the chance of white spot lesions. There is a need for new plaque control methods independent of patient's cooperation. Purpose: The aim of this study was to determine the effects of incorporating copper oxide (CuO) nanoparticles on antimicrobial properties and bond strength of orthodontic adhesive. Materials and Method: CuO nanoparticles were added to the composite transbond XT at concentrations of 0.01, 0.5 and 1 wt.%. To evaluate the antimicrobial properties of composites containing nanoparticles, the disk agar diffusion test was used. For this purpose, 10 discs from each concentration of nano-composites (totally 30 discs) and 10 discs from conventional composite (as the control group) were prepared. Then the diameter of streptococcus mutans growth inhibition around each disc was determined in blood agar medium. To evaluate the shear bond strength, with each concentration of nano-composites as well as the control group (conventional composite), 10 metal brackets were bonded to the human premolars and shear bond strength was determined using a universal testing machine. Results: Nano-composites in all three concentrations showed significant antimicrobial effect compared to the control group (p< 0.001). With increasing concentration of nanoparticles, antimicrobial effect showed an upward trend, although statistically was not significant. There was no significant difference between the shear bond strength of nano-composites compared to control group (p= 0.695). Conclusion: Incorporating CuO nanoparticles into adhesive in all three studied concentrations added antimicrobial effects to the adhesive with no adverse effects on shear bond strength. PMID:29492409

The Effect of CuO Nanoparticles on Antimicrobial Effects and Shear Bond Strength of Orthodontic Adhesives.

PubMed

Toodehzaeim, Mohammad Hossein; Zandi, Hengameh; Meshkani, Hamidreza; Hosseinzadeh Firouzabadi, Azadeh

2018-03-01

Orthodontic appliances facilitate microbial plaque accumulation and increase the chance of white spot lesions. There is a need for new plaque control methods independent of patient's cooperation. The aim of this study was to determine the effects of incorporating copper oxide (CuO) nanoparticles on antimicrobial properties and bond strength of orthodontic adhesive. CuO nanoparticles were added to the composite transbond XT at concentrations of 0.01, 0.5 and 1 wt.%. To evaluate the antimicrobial properties of composites containing nanoparticles, the disk agar diffusion test was used. For this purpose, 10 discs from each concentration of nano-composites (totally 30 discs) and 10 discs from conventional composite (as the control group) were prepared. Then the diameter of streptococcus mutans growth inhibition around each disc was determined in blood agar medium. To evaluate the shear bond strength, with each concentration of nano-composites as well as the control group (conventional composite), 10 metal brackets were bonded to the human premolars and shear bond strength was determined using a universal testing machine. Nano-composites in all three concentrations showed significant antimicrobial effect compared to the control group ( p < 0.001). With increasing concentration of nanoparticles, antimicrobial effect showed an upward trend, although statistically was not significant. There was no significant difference between the shear bond strength of nano-composites compared to control group ( p = 0.695). Incorporating CuO nanoparticles into adhesive in all three studied concentrations added antimicrobial effects to the adhesive with no adverse effects on shear bond strength.

Peptide-Conjugated Nanoparticles Reduce Positive Co-stimulatory Expression and T Cell Activity to Induce Tolerance.

PubMed

Kuo, Robert; Saito, Eiji; Miller, Stephen D; Shea, Lonnie D

2017-07-05

Targeted approaches to treat autoimmune diseases would improve upon current therapies that broadly suppress the immune system and lead to detrimental side effects. Antigen-specific tolerance was induced using poly(lactide-co-glycolide) nanoparticles conjugated with disease-relevant antigen to treat a model of multiple sclerosis. Increasing the nanoparticle dose and amount of conjugated antigen both resulted in more durable immune tolerance. To identify active tolerance mechanisms, we investigated downstream cellular and molecular events following nanoparticle internalization by antigen-presenting cells. The initial cell response to nanoparticles indicated suppression of inflammatory signaling pathways. Direct and functional measurement of surface MHC-restricted antigen showed positive correlation with both increasing particle dose from 1 to 100 μg/mL and increasing peptide conjugation by 2-fold. Co-stimulatory analysis of cells expressing MHC-restricted antigen revealed most significant decreases in positive co-stimulatory molecules (CD86, CD80, and CD40) following high doses of nanoparticles with higher peptide conjugation, whereas expression of a negative co-stimulatory molecule (PD-L1) remained high. T cells isolated from mice immunized against myelin proteolipid protein (PLP 139-151 ) were co-cultured with antigen-presenting cells administered PLP 139-151 -conjugated nanoparticles, which resulted in reduced T cell proliferation, increased T cell apoptosis, and a stronger anti-inflammatory response. These findings indicate several potential mechanisms used by peptide-conjugated nanoparticles to induce antigen-specific tolerance. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Radiation dose rate affects the radiosensitization of MCF-7 and HeLa cell lines to X-rays induced by dextran-coated iron oxide nanoparticles.

PubMed

Khoshgard, Karim; Kiani, Parvaneh; Haghparast, Abbas; Hosseinzadeh, Leila; Eivazi, Mohammad Taghi

2017-08-01

The aim of radiotherapy is to deliver lethal damage to cancerous tissue while preserving adjacent normal tissues. Radiation absorbed dose of the tumoral cells can increase when high atomic nanoparticles are present in them during irradiation. Also, the dose rate is an important aspect in radiation effects that determines the biological results of a given dose. This in vitro study investigated the dose-rate effect on the induced radiosensitivity by dextran-coated iron oxide in cancer cells. HeLa and MCF-7 cells were cultured in vitro and incubated with different concentrations of dextran-coated iron oxide nanoparticles. They were then irradiated with 6 MV photons at dose rates of 43, 185 and 370 cGy/min. The MTT test was used to obtain the cells' survival after 48 h of irradiations. Incubating the cells with the nanoparticles at concentrations of 10, 40 and 80 μg/ml showed no significant cytotoxicity effect. Dextran-coated iron oxide nanoparticles showed more radiosensitivity effect by increasing the dose rate and nanoparticles concentration. Radiosensitization enhancement factors of MCF-7 and HeLa cells at a dose-rate of 370 cGy/min and nanoparticles' concentration of 80 μg/ml were 1.21 ± 0.06 and 1.19 ± 0.04, respectively. Increasing the dose rate of 6 MV photons irradiation in MCF-7 and HeLa cells increases the radiosensitization induced by the dextran-coated iron nanoparticles in these cells.

Anti-inflammation effects of Sophora flavescens nanoparticles.

PubMed

Han, Chun-Chao; Wang, Yingzi

2012-08-01

The roots of Sophora flavescens was reported to possess many pharmacological activities including anti-inflammatory, antiashmatic, antithelmintic, free radical scavenging and antimicrobial activities. However, the low saturated solubility and dissolution velocity of S. flavescens lead to poor bioavailability. The S. flavescens nanoparticles (SFNP) were prepared by a combination of ultrasound and hydrolysis developed by the authors. The drug dissolution profiles of SFNP in both pH 6.8 and pH 2 media showed complete dissolution within 30 min. The seropharmacology study showed that oral S. flavescens absorption in the SFNP was significantly increased. Anti-inflammation assay revealed the therapeutic efficiency of S. flavescens significantly enhanced upon nanoparticle formation.

Bacopa monniera Stabilized Silver Nanoparticles Attenuates Oxidative Stress Induced by Aluminum in Albino Mice.

PubMed

Mahitha, B; Deva Prasad Raju, B; Mallikarjuna, K; Durga Mahalakshmi, Ch N; Sushmal, N John

2015-02-01

In the recent years usage of nanomedicine plays a promising strategy in the improvement of medical treatment. The ecofriendly synthesized silver nanoparticles has introduced a new opportunity to increase the efficacy of drug by reducing its side effects. In the present study, we investigated the antioxidant property of Bacopa monniera stabilized silver nanoparticles against aluminum induced toxicity in albino mice. Forty male albino mice were randomly divided into five groups. First group was treated as control, second group received aluminum acetate (5 mg/kg b . w), third group received Bacopa monniera extract (5 mg/kg b . w), fourth group received BmSNPs (5 mg/kg b . w), fifth group received aluminum acetate plus BmSNPs. Exposure to aluminum acetate significantly increased lipid peroxidation levels with a significant decrease in the antioxidant enzymes such as superoxide dismutase, catalase and glutathione peroxidase activities in the brain, liver and kidney of mice. Degenerative changes were also observed in brain, liver and kidney of aluminum treated mice. No significant changes in the oxidative stress were observed in the Bacopa monniera and BmSNPs alone treated mice. Whereas, co-administration of BmSNPs to Al treated mice showed a significant decrease in lipid peroxidation levels with a significant increase of SOD, CAT and GPx indicating the antioxidant potential of nanoparticles and in counteracting Al induced oxidative stress and histological response in male albino mice. These findings clearly implicate that BmSNPs are able to eradicate the oxidative stress and prevent the tissue damage in aluminum exposed mice.

Glioblastoma Targeted Gene Therapy Based on pEGFP/p53-Loaded Superparamagnetic Iron Oxide Nanoparticles.

PubMed

Eslaminejad, Touba; Nematollahi-Mahani, Seyed Noureddin; Ansari, Mehdi

2017-01-01

Blood-brain barrier (BBB) separates the neural tissue from circulating blood because of its high selectivity. This study focused on the in vitro application of magnetic nanoparticles to deliver Tp53 as a gene of interest to glioblastoma (U87) cells across a simulated BBB model that comprised KB cells. After magnetic and non-magnetic nanoparticles were internalized by KB cells, their location in these cells was examined by transmission electron microscopy. Transfection efficiency of DNA to U87 cells was evaluated by fluorescence microscopy, real time PCR, flowcytometry, and Western immuno-blotting. When a magnetic field was applied, a large number of magnetic nanoparticles accumulated in KB cells, appearing as black dots scattered in the cytoplasm of cells. Fluorescence microscope examination showed that transfection of the DNA to U87 target cells was highest in cells treated with magnetic nanoparticles and exposed to a magnetic field. Also it was reflected in significantly increased mRNA level while the p53 protein level was decreased. It could be concluded that a significant increase in total apoptosis was induced in cells by magnetic nanoparticles, coupled with exposure to a magnetic force (p ≤0.01) as compared with cells that were not exposed to magnetism. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Plasma - enhanced dispersion of metal and ceramic nanoparticles in polymer nanocomposite films

NASA Astrophysics Data System (ADS)

Maguire, Paul; Liu, Yazi; Askari, Sadegh; Patel, Jenish; Macia-Montero, Manuel; Mitra, Somak; Zhang, Richao; Sun, Dan; Mariotti, Davide

2015-09-01

In this work we demonstrate a facile method to synthesize a nanoparticle/PEDOT:PSS hybrid nanocomposite material in aqueous solution through atmospheric pressure direct current (DC) plasma processing at room temperature. Both metal (Au) and ceramic (TiO2) nanoparticle composite films have been fabricated. Nanoparticle dispersion is enhanced considerable and remains stable. TiO2/polymer hybrid nanoparticles with a distinct core shell structure have been obtained. Increased nanoparticle/PEDOT:PSS nanocomposite electrical conductivity has been observed. The improvement in nanocomposite properties is due to the enhanced dispersion and stability in liquid polymer of microplasma processed Au or TiO2 nanoparticles. Both plasma induced surface charge and nanoparticle surface termination with specific plasma chemical species are thought to provide an enhanced barrier to nanoparticle agglomeration and promote nanoparticle-polymer bonding. This is expected to have a significant benefit in materials processing with inorganic nanoparticles for applications in energy storage, photocatalysis and biomedical sensors. Engineering and Physical Sciences Research Council (EPSRC: EP/K006088/1, EP/K006142, Nos. EP/K022237/1).

Tumor stroma-containing 3D spheroid arrays: A tool to study nanoparticle penetration.

PubMed

Priwitaningrum, Dwi L; Blondé, Jean-Baptiste G; Sridhar, Adithya; van Baarlen, Joop; Hennink, Wim E; Storm, Gert; Le Gac, Séverine; Prakash, Jai

2016-12-28

Nanoparticle penetration through tumor tissue after extravasation is considered as a key issue for tumor distribution and therapeutic effects. Most tumors possess abundant stroma, a fibrotic tissue composed of cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM), which acts as a barrier for nanoparticle penetration. There is however a lack of suitable in vitro systems to study the tumor stroma penetration of nanoparticles. In the present study, we developed and thoroughly characterized a 3D co-culture spheroidal array to mimic tumor stroma and investigated the penetration of silica and PLGA nanoparticles in these spheroids. First, we examined human breast tumor patient biopsies to characterize the content and organization of stroma and found a high expression of alpha-smooth muscle actin (α-SMA; 40% positive area) and collagen-1 (50% positive area). Next, we prepared homospheroids of 4T1 mouse breast cancer cells or 3T3 mouse fibroblasts alone as well as heterospheroids combining 3T3 and 4T1 cells in different ratios (1:1 and 5:1) using a microwell array platform. Confocal live imaging revealed that fibroblasts distributed and reorganized within 48h in heterospheroids. Furthermore, immunohistochemical staining and gene expression analysis showed a proportional increase of α-SMA and collagen in heterospheroids with higher fibroblast ratios attaining 35% and 45% positive area at 5:1 (3T3:4T1) ratio, in a good match with the clinical breast tumor stroma. Subsequently, we studied the penetration of high and low negatively charged fluorescent silica nanoparticles (30nm; red and 100 or 70nm; green; zeta potential: -40mV and -20mV) and as well as Cy5-conjugated pegylated PLGA nanoparticles (200nm, -7mV) in both homo- and heterospheroid models. Fluorescent microscopy on spheroid cryosections after incubation with silica nanoparticles showed that 4T1 homospheroids allowed a high penetration of about 75-80% within 24h, with higher penetration in case of the 30nm nanoparticles. In contrast, spheroids with increasing fibroblast amounts significantly inhibited NP penetration. Silica nanoparticles with a less negative zeta potential exhibited lesser penetration compared to highly negative charged nanoparticles. Subsequently, similar experiments were conducted using Cy5-conjugated pegylated PLGA nanoparticles and confocal laser scanning microscopy; an increased nanoparticle penetration was found in 4T1 homospheroids until 48h, but significantly lower penetration in heterospheroids. Furthermore, we also developed human homospheroids (MDA-MB-231 or Panc-1 tumor cells) and heterospheroids (MDA-MB-231/BJ-hTert and Panc-1/pancreatic stellate cells) and performed silica nanoparticle (30 and 100nm) penetration studies. As a result, heterospheroids had significantly a lesser penetration of the nanoparticles compared to homospheroids. In conclusion, our data demonstrate that tumor stroma acts as a strong barrier for nanoparticle penetration. The 30-nm nanoparticles with low zeta potential favor deeper penetration. Furthermore, the herein proposed 3D co-culture platform that mimics the tumor stroma, is ideally suited to systematically investigate the factors influencing the penetration characteristics of newly developed nanomedicines to allow the design of nanoparticles with optimal penetration characteristics. Copyright © 2016 Elsevier B.V. All rights reserved.

A study of thermal conductivity in graphene diodes and transistors with intrinsic defects and subjected to metal impurities

NASA Astrophysics Data System (ADS)

Sadeghzadeh, Sadegh; Rezapour, Navid

2016-12-01

In this paper, the effect of the presence of cavities resulting from the fabrication process and the effect of common metal impurities added during the synthesis process on the thermal conductivity of single-layer graphene sheets, diodes and transistors have been investigated by using the Reverse Non Equilibrium Molecular Dynamics (RNEMD) method. The obtained results show that thermal conductivity generally diminishes by increasing the concentration of nanoparticles and increases when porosities and impurities are at the edges of sheets. Regarding a better thermal management in graphene with the addition of nanoparticles, and considering its existing porosity, a lower thermal conductivity is achieved by adding more nanoparticles. By increasing the diameter of pores from 0.5 nm to 4.4 nm in a specific single-layer graphene sheet, thermal conductivity diminishes from 67 W/mk to 1.43 W/mk; while it diminishes from 45 to 1.0 W/mk for the same structure containing both the defects and nanoparticles over the defects. In evaluating the influences of cavities and metallic nanoparticles on thermal conductivity, it was observed that changing the share of cavities or nanoparticles has a significant effect on the thermal conductivity of graphene diodes and transistors. The rectification efficiency of diodes diminished from about 100% for the defect-free diode to about 19% for the diode containing 2 nm cavities and then increased to 75% for the diode with 5 nm cavities. While, with the increase in the concentration of iron nanoparticles, the rectification efficiency increased from about 100% for the diode with no iron particles to about 255% for the diode containing 13 wt % of iron particles. Final results demonstrate that the metallic nanoparticles and also defects with specific diameters can be effectively exploited to increase or decrease the efficiency of nanodiodes and nanotransistors. This leads to engineered design of nanodiodes and nanotransistors for various applications.

Assessment of gold nanoparticles on human peripheral blood cells by metabolic profiling with 1H-NMR spectroscopy, a novel translational approach on a patient-specific basis.

PubMed

Palomino-Schätzlein, Martina; García, Hermenegildo; Gutiérrez-Carcedo, Patricia; Pineda-Lucena, Antonio; Herance, José Raul

2017-01-01

Human peripheral blood cells are relevant ex vivo models for characterizing diseases and evaluating the pharmacological effects of therapeutic interventions, as they provide a close reflection of an individual pathophysiological state. In this work, a new approach to evaluate the impact of nanoparticles on the three main fractions of human peripheral blood cells by nuclear magnetic resonance spectroscopy is shown. Thus, a comprehensive protocol has been set-up including the separation of blood cells, their in vitro treatment with nanoparticles and the extraction and characterization of metabolites by nuclear magnetic resonance. This method was applied to assess the effect of gold nanoparticles, either coated with chitosan or supported on ceria, on peripheral blood cells from healthy individuals. A clear antioxidant effect was observed for chitosan-coated gold nanoparticles by a significant increase in reduced glutathione, that was much less pronounced for gold-cerium nanoparticles. In addition, the analysis revealed significant alterations of several other pathways, which were stronger for gold-cerium nanoparticles. These results are in accordance with the toxicological data previously reported for these materials, confirming the value of the current methodology.

Engineering the lipid layer of lipid-PLGA hybrid nanoparticles for enhanced in vitro cellular uptake and improved stability.

PubMed

Hu, Yun; Hoerle, Reece; Ehrich, Marion; Zhang, Chenming

2015-12-01

Lipid-polymer hybrid nanoparticles (NPs), consisting of a polymeric core and a lipid shell, have been intensively examined as delivery systems for cancer drugs, imaging agents, and vaccines. For applications in vaccine particularly, the hybrid NPs need to be able to protect the enclosed antigens during circulation, easily be up-taken by dendritic cells, and possess good stability for prolonged storage. However, the influence of lipid composition on the performance of hybrid NPs has not been well studied. In this study, we demonstrate that higher concentrations of cholesterol in the lipid layer enable slower and more controlled antigen release from lipid-poly(lactide-co-glycolide) acid (lipid-PLGA) NPs in human serum and phosphate buffered saline (PBS). Higher concentrations of cholesterol also promoted in vitro cellular uptake of hybrid NPs, improved the stability of the lipid layer, and protected the integrity of the hybrid structure during long-term storage. However, stabilized hybrid structures of high cholesterol content tended to fuse with each other during storage, resulting in significant size increase and lowered cellular uptake. Additional experiments demonstrated that PEGylation of NPs could effectively minimize fusion-caused size increase after long term storage, leading to improved cellular uptake, although excessive PEGylation will not be beneficial and led to reduced improvement. This paper reports the engineering of the lipid layer that encloses a polymeric nanoparticle, which can be used as a carrier for drug and vaccine molecules for targeted delivery. We demonstrated that the concentration of cholesterol is critical for the stability and uptake of the hybrid nanoparticles by dendritic cells, a targeted cell for the delivery of immune effector molecules. However, we found that hybrid nanoparticles with high cholesterol concentration tend to fuse during storage resulting in larger particles with decreased cellular uptake. This problem is subsequently solved by PEGylating the hybrid nanoparticles. With increased research and clinical applications of lipid-polymer hybrid nanoparticles in drug and vaccine delivery, this work will significantly impact the design of the hybrid nanoparticles for minimized molecule release during circulation and increased bioavailability of the target molecules. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Enhanced dermal delivery of diflucortolone valerate using lecithin/chitosan nanoparticles: in-vitro and in-vivo evaluations.

PubMed

Özcan, Ipek; Azizoğlu, Erkan; Senyiğit, Taner; Özyazıcı, Mine; Özer, Özgen

2013-01-01

The objective of this study was to prepare a suitable formulation for dermal delivery of diflucortolone valerate (DFV) that would maintain the localization in skin layers without any penetration and to optimize efficiency of DFV. Drug-loaded lecithin/chitosan nanoparticles with high entrapment efficiency (86.8%), were successfully prepared by ionic interaction technique. Sustained release of DFV was achieved without any initial burst release. Nanoparticles were also incorporated into chitosan gel at different ratios for preparing a more suitable formulation for topical drug delivery with adequate viscosity. In ex-vivo permeation studies, nanoparticles increased the accumulation of DFV especially in the stratum corneum + epidermis of rat skin without any significant permeation. Retention of DFV from nanoparticle in chitosan gel formulation (0.01%) was twofold higher than commercial cream, although it contained ten times less DFV. Nanoparticles in gel formulations produced significantly higher edema inhibition in rats compared with commercial cream in in-vivo studies. Skin blanching assay using a chromameter showed vasoconstriction similar to that of the commercial product. There were no barrier function changes upon application of nanoparticles. In-vitro and in-vivo results demonstrated that lecithin/chitosan nanoparticles in chitosan gel may be a promising carrier for dermal delivery of DFV in various skin disorders.

Enhanced dermal delivery of diflucortolone valerate using lecithin/chitosan nanoparticles: in-vitro and in-vivo evaluations

PubMed Central

Özcan, İpek; Azizoğlu, Erkan; Şenyiğit, Taner; Özyazıcı, Mine; Özer, Özgen

2013-01-01

The objective of this study was to prepare a suitable formulation for dermal delivery of diflucortolone valerate (DFV) that would maintain the localization in skin layers without any penetration and to optimize efficiency of DFV. Drug-loaded lecithin/chitosan nanoparticles with high entrapment efficiency (86.8%), were successfully prepared by ionic interaction technique. Sustained release of DFV was achieved without any initial burst release. Nanoparticles were also incorporated into chitosan gel at different ratios for preparing a more suitable formulation for topical drug delivery with adequate viscosity. In ex-vivo permeation studies, nanoparticles increased the accumulation of DFV especially in the stratum corneum + epidermis of rat skin without any significant permeation. Retention of DFV from nanoparticle in chitosan gel formulation (0.01%) was twofold higher than commercial cream, although it contained ten times less DFV. Nanoparticles in gel formulations produced significantly higher edema inhibition in rats compared with commercial cream in in-vivo studies. Skin blanching assay using a chromameter showed vasoconstriction similar to that of the commercial product. There were no barrier function changes upon application of nanoparticles. In-vitro and in-vivo results demonstrated that lecithin/chitosan nanoparticles in chitosan gel may be a promising carrier for dermal delivery of DFV in various skin disorders. PMID:23390364

Toxicity and Transcriptome Sequencing (RNA-seq) Analyses of Adult Zebrafish in Response to Exposure Carboxymethyl Cellulose Stabilized Iron Sulfide Nanoparticles.

PubMed

Zheng, Min; Lu, Jianguo; Zhao, Dongye

2018-05-24

Increasing utilization of stabilized iron sulfides (FeS) nanoparticles implies an elevated release of the materials into the environment. To understand potential impacts and underlying mechanisms of nanoparticle-induced stress, we used the transcriptome sequencing (RNA-seq) technique to characterize the transcriptomes from adult zebrafish exposed to 10 mg/L carboxymethyl cellulose (CMC) stabilized FeS nanoparticles for 96 h, demonstrating striking differences in the gene expression profiles in liver. The exposure caused significant expression alterations in genes related to immune and inflammatory responses, detoxification, oxidative stress and DNA damage/repair. The complement and coagulation cascades Kyoto encyclopedia of genes and genomes (KEGG) pathway was found significantly up-regulated under nanoparticle exposure. The quantitative real-time polymerase chain reaction using twelve genes confirmed the RNA-seq results. We identified several candidate genes commonly regulated in liver, which may serve as gene indicators when exposed to the nanoparticles. Hepatic inflammation was further confirmed by histological observation of pyknotic nuclei, and vacuole formation upon exposure. Tissue accumulation tests showed a 2.2 times higher iron concentration in the fish tissue upon exposure. This study provides preliminary mechanistic insights into potential toxic effects of organic matter stabilized FeS nanoparticles, which will improve our understanding of the genotoxicity caused by stabilized nanoparticles.

A novel paclitaxel-loaded poly(epsilon-caprolactone)/Poloxamer 188 blend nanoparticle overcoming multidrug resistance for cancer treatment.

PubMed

Zhang, Yangqing; Tang, Lina; Sun, Leilei; Bao, Junbo; Song, Cunxian; Huang, Laiqiang; Liu, Kexin; Tian, Yan; Tian, Ge; Li, Zhen; Sun, Hongfan; Mei, Lin

2010-06-01

Multidrug resistance (MDR) of tumor cells is a major obstacle to the success of cancer chemotherapy. Poloxamers have been used in cancer therapy to overcome MDR. The objective of this research is to test the feasibility of paclitaxel-loaded poly(epsilon-caprolactone)/Poloxamer 188 (PCL/Poloxamer 188) nanoparticles to overcome MDR in a paclitaxel-resistant human breast cancer cell line. Paclitaxel-loaded nanoparticles were prepared by a water-acetone solvent displacement method using commercial PCL and self-synthesized PCL/Poloxamer 188 compound, respectively. PCL/Poloxamer 188 nanoparticles were found to be of spherical shape and tended to have a rough and porous surface. The nanoparticles had an average size of around 220nm, with a narrow size distribution. The in vitro drug release profile of both nanoparticle formulations showed a clear biphasic release pattern. There was an increased level of uptake of PCL/Poloxamer 188 nanoparticles (PPNP) in the paclitaxel-resistant human breast cancer cell line MCF-7/TAX, in comparison with PCL nanoparticles. The cytotoxicity of PCL nanoparticles was higher than commercial Taxol in the MCF-7/TAX cell culture, but the differences were not significant. However, the PCL/Poloxamer 188 nanoparticles achieved a significantly higher level of cytotoxicity than both of PCL nanoparticle formulation and Taxol(R), indicating that paclitaxel-loaded PCL/Poloxamer 188 nanoparticles could overcome MDR in human breast cancer cells and therefore could have considerable therapeutic potential for breast cancer. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Biophysical characterization of gold nanoparticles-loaded liposomes.

PubMed

Mady, Mohsen Mahmoud; Fathy, Mohamed Mahmoud; Youssef, Tareq; Khalil, Wafaa Mohamed

2012-10-01

Gold nanoparticles were prepared and loaded into the bilayer of dipalmitoylphosphatidylcholine (DPPC) liposomes, named as gold-loaded liposomes. Biophysical characterization of gold-loaded liposomes was studied by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy as well as turbidity and rheological measurements. FTIR measurements showed that gold nanoparticles made significant changes in the frequency of the CH(2) stretching bands, revealing that gold nanoparticles increased the number of gauche conformers and create a conformational change within the acyl chains of phospholipids. The transmission electron micrographs (TEM) revealed that gold nanoparticles were loaded in the liposomal bilayer. The zeta potential of DPPC liposomes had a more negative value after incorporating of Au NPs into liposomal membranes. Turbidity studies revealed that the loading of gold nanoparticles into DPPC liposomes results in shifting the temperature of the main phase transition to a lower value. The membrane fluidity of DPPC bilayer was increased by loading the gold nanoparticles as shown from rheological measurements. Knowledge gained in this study may open the door to pursuing liposomes as a viable strategy for Au NPs delivery in many diagnostic and therapeutic applications. Copyright © 2011 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Stability of polyelectrolyte-coated iron nanoparticles for T2-weighted magnetic resonance imaging

NASA Astrophysics Data System (ADS)

McGrath, Andrew J.; Dolan, Ciaran; Cheong, Soshan; Herman, David A. J.; Naysmith, Briar; Zong, Fangrong; Galvosas, Petrik; Farrand, Kathryn J.; Hermans, Ian F.; Brimble, Margaret; Williams, David E.; Jin, Jianyong; Tilley, Richard D.

2017-10-01

Iron nanoparticles are highly-effective magnetic nanoparticles for T2 magnetic resonance imaging (MRI). However, the stability of their magnetic properties is dependent on good protection of the iron core from oxidation in aqueous media. Here we report the synthesis of custom-synthesized phosphonate-grafted polyelectrolytes (PolyM3) of various chain lengths, for efficient coating of iron nanoparticles with a native iron oxide shell. The size of the nanoparticle-polyelectrolyte assemblies was investigated by transmission electron microscopy and dynamic light scattering, while surface attachment was confirmed by Fourier transform infrared spectroscopy. Low cytotoxicity was observed for each of the nanoparticle-polyelectrolyte ("Fe-PolyM3") assemblies, with good cell viability (>80%) remaining up to 100 μg mL-1 Fe in HeLa cells. When applied in T2-weighted MRI, corresponding T2 relaxivities (r2) of the Fe-PolyM3 assemblies were found to be dependent on the chain length of the polyelectrolyte. A significant increase in contrast was observed when polyelectrolyte chain length was increased from 6 to 65 repeating units, implying a critical chain length required for stabilization of the α-Fe nanoparticle core.

A review of the irradiation evolution of dispersed oxide nanoparticles in the b.c.c. Fe-Cr system: Current understanding and future directions

NASA Astrophysics Data System (ADS)

Wharry, Janelle P.; Swenson, Matthew J.; Yano, Kayla H.

2017-04-01

Thus far, a number of studies have investigated the irradiation evolution of oxide nanoparticles in b.c.c. Fe-Cr based oxide dispersion strengthened (ODS) alloys. But given the inconsistent experimental conditions, results have been widely variable and inconclusive. Crystal structure and chemistry changes differ from experiment to experiment, and the total nanoparticle volume fraction has been observed to both increase and decrease. Furthermore, there has not yet been a comprehensive review of the archival literature. In this paper, we summarize the existing studies on nanoparticle irradiation evolution. We note significant observations with respect to oxide nanoparticle crystallinity, composition, size, and number density. We discuss four possible contributing mechanisms for nanoparticle evolution: ballistic dissolution, Ostwald ripening, irradiation-enhanced diffusion, and homogeneous nucleation. Finally, we propose future directions to achieve a more comprehensive understanding of irradiation effects on oxide nanoparticles in ODS alloys.

Enhanced Intratumoral Delivery of SN38 as a Tocopherol Oxyacetate Prodrug Using Nanoparticles in a Neuroblastoma Xenograft Model.

PubMed

Nguyen, Ferro; Alferiev, Ivan; Guan, Peng; Guerrero, David T; Kolla, Venkatadri; Moorthy, Ganesh S; Chorny, Michael; Brodeur, Garrett M

2018-06-01

Purpose: Currently, <50% of high-risk pediatric solid tumors like neuroblastoma can be cured, and many survivors experience serious or life-threatening toxicities, so more effective, less toxic therapy is needed. One approach is to target drugs to tumors using nanoparticles, which take advantage of the enhanced permeability of tumor vasculature. Experimental Design: SN38, the active metabolite of irinotecan (CPT-11), is a potent therapeutic agent that is readily encapsulated in polymeric nanoparticles. Tocopherol oxyacetate (TOA) is a hydrophobic mitocan that was linked to SN38 to significantly increase hydrophobicity and enhance nanoparticle retention. We treated neuroblastomas with SN38-TOA nanoparticles and compared the efficacy with the parent prodrug CPT-11 using a mouse xenograft model. Results: Nanoparticle treatment induced prolonged event-free survival (EFS) in most mice, compared with CPT-11. This was shown for both SH-SY5Y and IMR-32 neuroblastoma xenografts. Enhanced efficacy was likely due to increased and sustained drug levels of SN38 in the tumor compared with conventional CPT-11 delivery. Interestingly, when recurrent CPT-11-treated tumors were re-treated with SN38-TOA nanoparticles, the tumors transformed from undifferentiated neuroblastomas to maturing ganglioneuroblastomas. Furthermore, these tumors were infiltrated with Schwann cells of mouse origin, which may have contributed to the differentiated histology. Conclusions: Nanoparticle delivery of SN38-TOA produced increased drug delivery and prolonged EFS compared to conventional delivery of CPT-11. Also, lower total dose and drug entrapment in nanoparticles during circulation should decrease toxicity. We propose that nanoparticle-based delivery of a rationally designed prodrug is an attractive approach to enhance chemotherapeutic efficacy in pediatric and adult tumors. Clin Cancer Res; 24(11); 2585-93. ©2018 AACR . ©2018 American Association for Cancer Research.

Synthesis and characterization of bioactive conjugated near-infrared fluorescent proteinoid-poly(L-lactic acid) hollow nanoparticles for optical detection of colon cancer

PubMed Central

Kolitz-Domb, Michal; Corem-Salkmon, Enav; Grinberg, Igor; Margel, Shlomo

2014-01-01

Colon cancer is one of the major causes of death in the Western world. Early detection significantly improves long-term survival for patients with colon cancer. Near-infrared (NIR) fluorescent nanoparticles are promising candidates for use as contrast agents for tumor detection. Using NIR offers several advantages for bioimaging compared with fluorescence in the visible spectrum: lower autofluorescence of biological tissues and lower absorbance and, consequently, deeper penetration into biomatrices. The present study describes the preparation of new NIR fluorescent proteinoid-poly(L-lactic acid) (PLLA) nanoparticles. For this purpose, a P(EF-PLLA) random copolymer was prepared by thermal copolymerization of L-glutamic acid (E) with L-phenylalanine (F) and PLLA. Under suitable conditions, this proteinoid-PLLA copolymer can self-assemble to nanosized hollow particles of relatively narrow size distribution. This self-assembly process was used for encapsulation of the NIR dye indocyanine green. The encapsulation process increases significantly the photostability of the dye. These NIR fluorescent nanoparticles were found to be stable and nontoxic. Leakage of the NIR dye from these nanoparticles into phosphate-buffered saline containing 4% human serum albumin was not detected. Tumor-targeting ligands such as peanut agglutinin and anticarcinoembryonic antigen antibodies were covalently conjugated to the surface of the NIR fluorescent P(EF-PLLA) nanoparticles, thereby increasing the fluorescent signal of tumors with upregulated corresponding receptors. Specific colon tumor detection by the NIR fluorescent P(EF-PLLA) nanoparticles was demonstrated in a chicken embryo model. In future work, we plan to extend this study to a mouse model, as well as to encapsulate a cancer drug such as doxorubicin within these nanoparticles for therapeutic applications. PMID:25382975

Evaluation of Flexural Strength of Polymethyl Methacrylate modified with Silver Colloidal Nanoparticles subjected to Two Different Curing Cycles: An in vitro Study.

PubMed

Munikamaiah, Ranganath L; Jain, Saket K; Pal, Kapil S; Gaikwad, Ajay

2018-03-01

Silver colloidal nanoparticles have been incorporated into acrylic resins to induce antimicrobial properties. However, as additives, they can influence the mechanical properties of the final product. Mechanical properties are also dependent on different curing cycles. The aim of this study was to evaluate flexural strength of a denture base resin incorporated with different concentrations of silver colloidal nanoparticles subjected to two different curing cycles. Lucitone 199 denture base resin was used into which silver colloidal nanoparticles were incorporated at 0.5 and 5% by polymer mass. Specimens devoid of nanoparticles were used as controls. A total of 60 specimens were fabricated and divided into two groups. Each group was divided into three subgroups consisting of 10 specimens each. The specimens were fabricated according to American Dental Association (ADA) specification No. 12 and tested for flexural strength using universal testing machine. Silver colloidal nanoparticle incorporation at 0.5% concentration increased the mean flexural strength in both curing cycles by 7.5 and 4.4%, respectively, when compared with the control group. The study suggested that the mean flexural strength value of 0.5% silver colloidal nanoparticles in denture base resin was above the value of the control group both in short and long curing cycles, which makes it clinically suitable as a denture base material. However, at 5% concentration, the statistically significant amount of decrease in flexural strength compared with the value of control group both in short and long curing cycles gives it a questionable prognosis. The specimens incorporated with the antimicrobial agent 0.5% silver colloidal nanoparticles and processed by long curing cycles showed significant increase in its flexural strength compared with the control group, which makes it clinically suitable as a denture base material.

Heat and Mass Transfer Analysis of MHD Nanofluid Flow with Radiative Heat Effects in the Presence of Spherical Au-Metallic Nanoparticles

NASA Astrophysics Data System (ADS)

Qureshi, M. Zubair Akbar; Rubbab, Qammar; Irshad, Saadia; Ahmad, Salman; Aqeel, M.

2016-10-01

Energy generation is currently a serious concern in the progress of human civilization. In this regard, solar energy is considered as a significant source of renewable energy. The purpose of the study is to establish a thermal energy model in the presence of spherical Au-metallic nanoparticles. It is numerical work which studies unsteady magnetohydrodynamic (MHD) nanofluid flow through porous disks with heat and mass transfer aspects. Shaped factor of nanoparticles is investigated using small values of the permeable Reynolds number. In order to scrutinize variation of thermal radiation effects, a dimensionless Brinkman number is introduced. The results point out that heat transfer significantly escalates with the increase of Brinkman number. Partial differential equations that govern this study are reduced into nonlinear ordinary differential equations by means of similarity transformations. Then using a shooting technique, a numerical solution of these equations is constructed. Radiative effects on temperature and mass concentration are quite opposite. Heat transfer increases in the presence of spherical Au-metallic nanoparticles.

Heat and Mass Transfer Analysis of MHD Nanofluid Flow with Radiative Heat Effects in the Presence of Spherical Au-Metallic Nanoparticles.

PubMed

Qureshi, M Zubair Akbar; Rubbab, Qammar; Irshad, Saadia; Ahmad, Salman; Aqeel, M

2016-12-01

Energy generation is currently a serious concern in the progress of human civilization. In this regard, solar energy is considered as a significant source of renewable energy. The purpose of the study is to establish a thermal energy model in the presence of spherical Au-metallic nanoparticles. It is numerical work which studies unsteady magnetohydrodynamic (MHD) nanofluid flow through porous disks with heat and mass transfer aspects. Shaped factor of nanoparticles is investigated using small values of the permeable Reynolds number. In order to scrutinize variation of thermal radiation effects, a dimensionless Brinkman number is introduced. The results point out that heat transfer significantly escalates with the increase of Brinkman number. Partial differential equations that govern this study are reduced into nonlinear ordinary differential equations by means of similarity transformations. Then using a shooting technique, a numerical solution of these equations is constructed. Radiative effects on temperature and mass concentration are quite opposite. Heat transfer increases in the presence of spherical Au-metallic nanoparticles.

Effects of Ti doping on the dielectric properties of HfO{sub 2} nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pokhriyal, S.; Biswas, S., E-mail: drsomnathbiswas@gmail.com

2016-05-06

We report the effects of Ti doping on the dielectric properties of HfO{sub 2} [Hf{sub 1-x}Ti{sub x}O{sub 2} (x = 0.2-0.8)] nanoparticles at room temperature. The Hf{sub 1-x}Ti{sub x}O{sub 2} nanoparticles were synthesized by a wet chemical process. The structural and morphological properties of the derived samples were analyzed with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and high resolution transmission electron microscopy (HRTEM). Impedance analysis was performed in pelletized samples in the frequency range of 1 MHz to 1 GHz. The obtained results were analyzed in correlation with microstructure and doping concentration in the derived samples. The averagemore » size of the Hf{sub 1-x}Ti{sub x}O{sub 2} nanoparticles is typically in the range of 4-8 nm depending on the processing temperature. The Hf{sub 1−x}Ti{sub x}O{sub 2} nanoparticles show reduction in crystallinity with the increase in Ti doping. The dielectric constants of the derived samples decrease with the increase in frequency. The ac-conductivity in the samples increases with the increase in frequency irrespective of Ti concentration and shows significant drop with the increase in Ti concentration at all frequencies.« less

Wall slipping behavior of foam with nanoparticle-armored bubbles and its flow resistance factor in cracks.

PubMed

Lv, Qichao; Li, Zhaomin; Li, Binfei; Husein, Maen; Shi, Dashan; Zhang, Chao; Zhou, Tongke

2017-07-11

In this work, wall slipping behavior of foam with nanoparticle-armored bubbles was first studied in a capillary tube and the novel multiphase foam was characterized by a slipping law. A crack model with a cuboid geometry was then used to compare with the foam slipping results from the capillary tube and also to evaluate the flow resistance factor of the foam. The results showed that the slipping friction force F FR in the capillary tube significantly increased by addition of modified SiO 2 nanoparticles, and an appropriate power law exponents by fitting F FR vs. Capillary number, Ca, was 1/2. The modified nanoparticles at the surface were bridged together and formed a dense particle "armor" surrounding the bubble, and the interconnected structures of the "armor" with strong steric integrity made the surface solid-like, which was in agreement with the slip regime associated with rigid surface. Moreover, as confirmed by 3D microscopy, the roughness of the bubble surface increased with nanoparticle concentration, which in turn increased the slipping friction force. Compared with pure SDBS foam, SDBS/SiO 2 foam shows excellent stability and high flow resistance in visual crack. The resistance factor of SiO 2 /SDBS foam increased as the wall surface roughness increased in core cracks.

The effect of green synthesized gold nanoparticles on rice germination and roots

NASA Astrophysics Data System (ADS)

Tsi Ndeh, Nji; Maensiri, Santi; Maensiri, Duangkamol

2017-09-01

In this paper, gold nanoparticles were synthesized by means of a green approach with Tiliacora triandra leaf extracts under different conditions. No additional reducing or capping agents were employed. The gold nanoparticles were characterized using UV-visible spectrophotometry, transmission electron microscope, x-ray diffraction and Fourier transform infrared spectroscopy. Gold nanoparticles synthesized at temperature of 80 °C were further used to treat rice (Oryza sativa) grains at different concentrations (0, 10, 100, 500, 1000, 2000 mg l-1) for one week. While germination percentages were high (95-98.38%), a slight decrease in root and shoot lengths relative to the control was observed. Phytotoxicity results indicated that the plant synthesized gold nanoparticles were of minimal toxicity to rice seedlings. Increases in cell death, hydrogen peroxide formation and lipid peroxidation in roots and shoots were noted. However, these increases were not statistically significant. The overall results confirmed that Tiliacora triandra synthesized gold nanoparticles are biocompatible and can be potentially used as nanocarriers in agriculture. Contribution at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

Targeting tumor highly-expressed LAT1 transporter with amino acid-modified nanoparticles: Toward a novel active targeting strategy in breast cancer therapy.

PubMed

Li, Lin; Di, Xingsheng; Wu, Mingrui; Sun, Zhisu; Zhong, Lu; Wang, Yongjun; Fu, Qiang; Kan, Qiming; Sun, Jin; He, Zhonggui

2017-04-01

Designing active targeting nanocarriers with increased cellular accumulation of chemotherapeutic agents is a promising strategy in cancer therapy. Herein, we report a novel active targeting strategy based on the large amino acid transporter 1 (LAT1) overexpressed in a variety of cancers. Glutamate was conjugated to polyoxyethylene stearate as a targeting ligand to achieve LAT1-targeting PLGA nanoparticles. The targeting efficiency of nanoparticles was investigated in HeLa and MCF-7 cells. Significant increase in cellular uptake and cytotoxicity was observed in LAT1-targeting nanoparticles compared to the unmodified ones. More interestingly, the internalized LAT1 together with targeting nanoparticles could recycle back to the cell membrane within 3 h, guaranteeing sufficient transporters on cell membrane for continuous cellular uptake. The LAT1 targeting nanoparticles exhibited better tumor accumulation and antitumor effects. These results suggested that the overexpressed LAT1 on cancer cells holds a great potential to be a high-efficiency target for the rational design of active-targeting nanosystems. Copyright © 2016 Elsevier Inc. All rights reserved.

Controlled release from bilayer-decorated magnetoliposomes via electromagnetic heating.

PubMed

Chen, Yanjing; Bose, Arijit; Bothun, Geoffrey D

2010-06-22

Nanoscale assemblies that can be activated and controlled through external stimuli represent a next stage in multifunctional therapeutics. We report the formation, characterization, and release properties of bilayer-decorated magnetoliposomes (dMLs) that were prepared by embedding small hydrophobic SPIO nanoparticles at different lipid molecule to nanoparticle ratios within dipalmitoylphosphatidylcholine (DPPC) bilayers. The dML structure was examined by cryogenic transmission electron microscopy and differential scanning calorimetry, and release was examined by carboxyfluorescein leakage. Nanoparticle heating using alternating current electromagnetic fields (EMFs) operating at radio frequencies provided selective release of the encapsulated molecule at low nanoparticle concentrations and under physiologically acceptable EMF conditions. Without radio frequency heating, spontaneous leakage from the dMLs decreased with increasing nanoparticle loading, consistent with greater bilayer stability and a decrease in the effective dML surface area due to aggregation. With radio frequency heating, the initial rate and extent of leakage increased significantly as a function of nanoparticle loading and electromagnetic field strength. The mechanism of release is attributed to a combination of bilayer permeabilization and partial dML rupture.

Spontaneous synthesis of gold nanoparticles on gum arabic-modified iron oxide nanoparticles as a magnetically recoverable nanocatalyst.

PubMed

Wu, Chien-Chen; Chen, Dong-Hwang

2012-06-19

A novel magnetically recoverable Au nanocatalyst was fabricated by spontaneous green synthesis of Au nanoparticles on the surface of gum arabic-modified Fe3O4 nanoparticles. A layer of Au nanoparticles with thickness of about 2 nm was deposited on the surface of gum arabic-modified Fe3O4 nanoparticles, because gum arabic acted as a reducing agent and a stabilizing agent simultaneously. The resultant magnetically recoverable Au nanocatalyst exhibited good catalytic activity for the reduction of 4-nitrophenol with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increase in the amount of Au nanocatalyst or decrease in the initial concentration of 4-nitrophenol. The kinetic data suggested that this catalytic reaction was diffusion-controlled, owing to the presence of gum arabic layer. In addition, this nanocatalyst exhibited good stability. Its activity had no significant decrease after five recycles. This work is useful for the development and application of magnetically recoverable Au nanocatalyst on the basis of green chemistry principles.

Spontaneous synthesis of gold nanoparticles on gum arabic-modified iron oxide nanoparticles as a magnetically recoverable nanocatalyst

PubMed Central

2012-01-01

A novel magnetically recoverable Au nanocatalyst was fabricated by spontaneous green synthesis of Au nanoparticles on the surface of gum arabic-modified Fe3O4 nanoparticles. A layer of Au nanoparticles with thickness of about 2 nm was deposited on the surface of gum arabic-modified Fe3O4 nanoparticles, because gum arabic acted as a reducing agent and a stabilizing agent simultaneously. The resultant magnetically recoverable Au nanocatalyst exhibited good catalytic activity for the reduction of 4-nitrophenol with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increase in the amount of Au nanocatalyst or decrease in the initial concentration of 4-nitrophenol. The kinetic data suggested that this catalytic reaction was diffusion-controlled, owing to the presence of gum arabic layer. In addition, this nanocatalyst exhibited good stability. Its activity had no significant decrease after five recycles. This work is useful for the development and application of magnetically recoverable Au nanocatalyst on the basis of green chemistry principles. PMID:22713480

[Application of subserosal injection of carbon nanoparticles via infusion needle to label lymph nodes in laparoscopic radical gastrectomy].

PubMed

Chen, Hongyuan; Wang, Yanan; Xue, Fangqin; Yu, Jiang; Hu, Yanfeng; Liu, Hao; Yan, Jun; Li, Guoxin

2014-05-01

To explore the feasibility of subserosal injection of carbon nanoparticle via venous infusion needle to label lymph node and its application value in laparoscopic radical gastrectomy. Forty patients with gastric cancer were randomly divided into two groups (carbon nanoparticle group and control group). Subserosal injection of carbon nanoparticle around the tumor was performed via venous infusion needle laparoscopically at the beginning of surgery in carbon nanoparticles group, while the patients routinely underwent laparoscopic radical gastrectomy in control group. Results of harvested lymph nodes were compared between the two groups. The perioperative complications and the side effect of carbon nanoparticle were also evaluated. The average number of harvested lymph node in carbon nanoparticle group (31.7±7.6) was significantly higher than that in control group (19.8±6.1, P<0.05). The proportion of harvested small node (< 5 mm) in carbon nanoparticles group(61.0%) was higher than that in control group(43.3%, P<0.01). The mean harvest time in carbon nanoparticle group [(23.5±4.8) min] was shorter than that in control group [(32.6±5.5) min, P<0.05]. The rate of black-dyed harvested lymph node was 61.9% and the metastasis rate of black-dyed lymph node was 23.0% in carbon nanoparticle group, which were significantly higher than those without black-dyed(6.2%, P<0.05) and those in control group (15.7%, P<0.05). The operative time and perioperative complications were not significantly different between the two groups, and no serious side effect caused by carbon nanoparticle was observed. Subserosal injection of carbon nanoparticle via venous infusion needle to label lymph nodes during laparoscopic radical gastrectomy is safe and feasible. It can increase the number of harvested lymph node, especially the small node.

Biodirected synthesis of Miconazole-conjugated bacterial silver nanoparticles and their application as antifungal agents and drug delivery vehicles.

PubMed

Kumar, C Ganesh; Poornachandra, Y

2015-01-01

The recent strategy to improve the efficacy of drugs is to combine them with metal nanoparticles for the control of microbial infections. Considering this fact, we developed a low cost and eco-friendly method for silver nanoparticles synthesis using the cell free supernatant of Delftia sp. strain KCM-006 and their application as antifungal agents and as a drug carrier. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis revealed the formation of spherical and monodispersed silver nanoparticles with an average size of 9.8 nm. The synthesized nanoparticles were found to be photoluminescent, highly stable and crystalline in nature having a zeta potential of -31 mV. The silver nanoparticles exhibited very good antifungal activity against various pathogenic Candida strains. Furthermore, the efficacy of nanoparticles was increased by conjugating the antifungal drug Miconazole to silver nanoparticles which exhibited significant fungicidal activity, inhibition of ergosterol biosynthesis and biofilm inhibition by increasing ROS levels. In addition, the cell viability and immunocytochemistry analysis against different normal cell lines including Chinese hamster ovary cells (CHO), human lung cell line (MRC5) and human vascular endothelial cells (HUVEC) demonstrated that these nanoparticles were non-toxic up to a concentration of 20 μM. In conclusion, these results suggest that the synthesized nanoparticles find application as both antifungal agents and drug delivery vehicles. This is a first report on the preparation of silver nanoparticles using culture supernatant from Delftia sp. and also on the conjugation of Miconazole, an antifungal drug, to the bacterial silver nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

GEANT 4 simulation of (99)Mo photonuclear production in nanoparticles.

PubMed

Dikiy, N P; Dovbnya, A N; Fedorchenko, D V; Khazhmuradov, M A

2016-08-01

GEANT 4 Monte-Carlo simulation toolkit is used to study the kinematic recoil method of (99)Mo photonuclear production. Simulation for bremsstrahlung photon spectrum with maximum photon energy 30MeV showed that for MoO3 nanoparticle escape fraction decreases from 0.24 to 0.08 when nanoparticle size increases from 20nm to 80nm. For the natural molybdenum and pure (100)Mo we obtained the lower values: from 0.17 to 0.05. The generation of accompanying molybdenum nuclei is significantly lower for pure (100)Mo and is about 3.6 nuclei per single (99)Mo nucleus, while natural molybdenum nanoparticle produce about 48 accompanying nuclei. Also, we have shown that for high-energy photons escape fraction of (99)Mo decreases, while production of unwanted molybdenum isotopes is significantly higher. Copyright © 2016 Elsevier Ltd. All rights reserved.

Interactions between amino-phosphonates pesticides and titanium dioxide nanoparticle in water: consequences on their mobility

NASA Astrophysics Data System (ADS)

Ilina, Svetlana; Baran, Nicole; Slomberg, Danielle; Devau, Nicolas; Pariat, Anne; Sani-Kast, Nicole; Scheringer, Martin; Labille, Jérôme; Ollivier, patrick

2017-04-01

Water quality is increasingly monitored worldwide, where various levels of nitrate and pesticide and/or metabolite contamination have been confirmed. Glyphosate [N-(phosphonomethyl)glycine] is probably the most widely used herbicide in the world. AMPA [aminomethylphosphonic acid] is its main degradation product. Although glyphosate mobility in the environment is supposed to be limited because of its high adsorption capacity in soils several studies show that glyphosate may reach both surface and ground-waters either by transport in dissolved form, or particle bonded onto soil colloids. At the same time, in recent years, rapid development of new technologies has resulted in a significant increase in the production and uses of products containing nanoparticles, notably dioxide titanium nanoparticles. This enthusiasm for nanotechnology is however accompanied by awareness about the potential release and impact of the nanoparticles in the environment. The aim of the study is to increase the knowledge on pesticide and nanoparticles interactions that may be present as contaminant cocktail in waters. Thanks to lab-experiments conducted with glyphosate or AMPA and rutile or anatase under different water chemistry conditions (pH, ionic strength, presence and concentrations of mono- and bivalent cations), we were able to describe the colloidal stability of nanoparticles that control their mobility and to characterize the sorption of pesticide on these nanoparticles and their transformation.

Effect of Particle Size on Thermal Conductivity of Nanofluid

NASA Astrophysics Data System (ADS)

Chopkar, M.; Sudarshan, S.; Das, P. K.; Manna, I.

2008-07-01

Nanofluids, containing nanometric metallic or oxide particles, exhibit extraordinarily high thermal conductivity. It is reported that the identity (composition), amount (volume percent), size, and shape of nanoparticles largely determine the extent of this enhancement. In the present study, we have experimentally investigated the impact of Al2Cu and Ag2Al nanoparticle size and volume fraction on the effective thermal conductivity of water and ethylene glycol based nanofluid prepared by a two-stage process comprising mechanical alloying of appropriate Al-Cu and Al-Ag elemental powder blend followed by dispersing these nanoparticles (1 to 2 vol pct) in water and ethylene glycol with different particle sizes. The thermal conductivity ratio of nanofluid, measured using an indigenously developed thermal comparator device, shows a significant increase of up to 100 pct with only 1.5 vol pct nanoparticles of 30- to 40-nm average diameter. Furthermore, an analytical model shows that the interfacial layer significantly influences the effective thermal conductivity ratio of nanofluid for the comparable amount of nanoparticles.

[The effect of entrapment of CpG sequence with cationic PLG nanoparticles on the immune responses of mice to pig paratyphoid vaccine].

PubMed

Wu, Mei; Shi, Ling; Liu, Shigui; Li, Jiangling; Wu, Kaiyuan; Wang, Lihuan; Shen, Yi; Liu, Kun; Zheng, Yong; Zhang, Xinshen; Gao, Rong

2005-10-01

Cationic PLG nanoparticles and liposome were prepared and used as package molecules to pack up pUC18-CpG. The effects of the packed pUC18-CpG on the cellular and humoral immune responses were detected in the mice that were inoculated with pig paratyphoid vaccine. The results showed that compared with the control, the amount of IgG and the titre of specific antibody were significantly increased in the sera of mice immunized with the CpG plasmid entrapped by cationic PLG nanoparticles; the proliferation and induced IL-2 bioactivity of lymphocytes were significantly enhanced in the spleen of the immunized mice; the stimulatory effect of cationic PLG nanoparticles was similar to or stronger than that of cationic liposome. These indicated that cationic PLG nanoparticle could be employed as an effective package molecule to promote the immunostimulatory effect of pUC18-CpG.

The antifungal effect of silver nanoparticles on Trichosporon asahii.

PubMed

Xia, Zhi-Kuan; Ma, Qiu-Hua; Li, Shu-Yi; Zhang, De-Quan; Cong, Lin; Tian, Yan-Li; Yang, Rong-Ya

2016-04-01

Silver nanoparticles are receiving increasing attention in biomedical applications. This study aims at evaluating the antifungal properties of silver nanoparticles against the pathogenic fungus Trichosporon asahii. The growth of T. asahii on potato dextrose agar medium containing different concentrations of silver nanoparticles was examined and the antifungal effect was evaluated using minimum inhibitory concentration. Scanning and transmission electron microscopy were also used to investigate the antifungal effect of silver nanoparticles on T. asahii. Silver nanoparticles had a significant inhibitory effect on the growth of T. asahii. The minimum inhibitory concentration of silver nanoparticles against T. asahii was 0.5 μg/mL, which was lower than amphotericin B, 5-flucytosine, caspofungin, terbinafine, fluconazole, and itraconazole and higher than voriconazole. Silver nanoparticles obviously damaged the cell wall, cell membrane, mitochondria, chromatin, and ribosome. Our results demonstrate that silver nanoparticles have good antifungal activity against T. asahii. Based on our electron microscopy observations, silver nanoparticles may inhibit the growth of T. asahii by permeating the fungal cell and damaging the cell wall and cellular components. Copyright © 2014. Published by Elsevier B.V.

Photoinduced Disaggregation of TiO2 Nanoparticles Enables Transdermal Penetration

PubMed Central

Bennett, Samuel W.; Zhou, Dongxu; Mielke, Randall; Keller, Arturo A.

2012-01-01

Under many aqueous conditions, metal oxide nanoparticles attract other nanoparticles and grow into fractal aggregates as the result of a balance between electrostatic and Van Der Waals interactions. Although particle coagulation has been studied for over a century, the effect of light on the state of aggregation is not well understood. Since nanoparticle mobility and toxicity have been shown to be a function of aggregate size, and generally increase as size decreases, photo-induced disaggregation may have significant effects. We show that ambient light and other light sources can partially disaggregate nanoparticles from the aggregates and increase the dermal transport of nanoparticles, such that small nanoparticle clusters can readily diffuse into and through the dermal profile, likely via the interstitial spaces. The discovery of photoinduced disaggregation presents a new phenomenon that has not been previously reported or considered in coagulation theory or transdermal toxicological paradigms. Our results show that after just a few minutes of light, the hydrodynamic diameter of TiO2 aggregates is reduced from ∼280 nm to ∼230 nm. We exposed pigskin to the nanoparticle suspension and found 200 mg kg−1 of TiO2 for skin that was exposed to nanoparticles in the presence of natural sunlight and only 75 mg kg−1 for skin exposed to dark conditions, indicating the influence of light on NP penetration. These results suggest that photoinduced disaggregation may have important health implications. PMID:23155401

Controlled synthesis of germanium nanoparticles by nonthermal plasmas

NASA Astrophysics Data System (ADS)

Ahadi, Amir Mohammad; Hunter, Katharine I.; Kramer, Nicolaas J.; Strunskus, Thomas; Kersten, Holger; Faupel, Franz; Kortshagen, Uwe R.

2016-02-01

The size, composition, and crystallinity of plasma produced nanoparticles are crucial factors for their physical and chemical properties. Here, we investigate the role of the process gas composition, particularly the hydrogen (H2) flow rate, on germanium (Ge) nanoparticles synthesized from a chlorinated precursor by nonthermal plasma. We demonstrate that the gas composition can significantly change the nanoparticle size and also adjust the surface chemistry by altering the dominant reaction mechanisms. A red shift of the Ge-Clx infrared absorptions with increasing H2 flow indicates a weakening of the Ge-Clx bonds at high H2 content. Furthermore, by changing the gas composition, the nanoparticles microstructure can be controlled from mostly amorphous at high hydrogen flow to diamond cubic crystalline at low hydrogen flow.

PEGylated PLGA-based nanoparticles targeting M cells for oral vaccination.

PubMed

Garinot, Marie; Fiévez, Virginie; Pourcelle, Vincent; Stoffelbach, François; des Rieux, Anne; Plapied, Laurence; Theate, Ivan; Freichels, Hélène; Jérôme, Christine; Marchand-Brynaert, Jacqueline; Schneider, Yves-Jacques; Préat, Véronique

2007-07-31

To improve the efficiency of orally delivered vaccines, PEGylated PLGA-based nanoparticles displaying RGD molecules at their surface were designed to target human M cells. RGD grafting was performed by an original method called "photografting" which covalently linked RGD peptides mainly on the PEG moiety of the PCL-PEG, included in the formulation. First, three non-targeted formulations with size and zeta potential adapted to M cell uptake and stable in gastro-intestinal fluids, were developed. Their transport by an in vitro model of the human Follicle associated epithelium (co-cultures) was largely increased as compared to mono-cultures (Caco-2 cells). RGD-labelling of nanoparticles significantly increased their transport by co-cultures, due to interactions between the RGD ligand and the beta(1) intregrins detected at the apical surface of co-cultures. In vivo studies demonstrated that RGD-labelled nanoparticles particularly concentrated in M cells. Finally, ovalbumin-loaded nanoparticles were orally administrated to mice and induced an IgG response, attesting antigen ability to elicit an immune response after oral delivery.

Evaluation of the local dose enhancement in the combination of proton therapy and nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martínez-Rovira, I., E-mail: immamartinez@gmail.com; Prezado, Y.

Purpose: The outcome of radiotherapy can be further improved by combining irradiation with dose enhancers such as high-Z nanoparticles. Since 2004, spectacular results have been obtained when low-energy x-ray irradiations have been combined with nanoparticles. Recently, the same combination has been explored in hadron therapy. In vitro studies have shown a significant amplification of the biological damage in tumor cells charged with nanoparticles and irradiated with fast ions. This has been attributed to the increase in the ionizations and electron emissions induced by the incident ions or the electrons in the secondary tracks on the high-Z atoms, resulting in amore » local energy deposition enhancement. However, this subject is still a matter of controversy. Within this context, the main goal of the authors’ work was to provide new insights into the dose enhancement effects of nanoparticles in proton therapy. Methods: For this purpose, Monte Carlo calculations (GATE/GEANT4 code) were performed. In particular, the GEANT4-DNA toolkit, which allows the modeling of early biological damages induced by ionizing radiation at the DNA scale, was used. The nanometric radial energy distributions around the nanoparticle were studied, and the processes (such as Auger deexcitation or dissociative electron attachment) participating in the dose deposition of proton therapy treatments in the presence of nanoparticles were evaluated. It has been reported that the architecture of Monte Carlo calculations plays a crucial role in the assessment of nanoparticle dose enhancement and that it may introduce a bias in the results or amplify the possible final dose enhancement. Thus, a dosimetric study of different cases was performed, considering Au and Gd nanoparticles, several nanoparticle sizes (from 4 to 50 nm), and several beam configurations (source-nanoparticle distances and source sizes). Results: This Monte Carlo study shows the influence of the simulations’ parameters on the local dose enhancement and how more realistic configurations lead to a negligible increase of local energy deposition. The obtained dose enhancement factor was up to 1.7 when the source was located at the nanoparticle surface. This dose enhancement was reduced when the source was located at further distances (i.e., in more realistic situations). Additionally, no significant increase in the dissociative electron attachment processes was observed. Conclusions: The authors’ results indicate that physical effects play a minor role in the amplification of damage, as a very low dose enhancement or increase of dissociative electron attachment processes is observed when the authors get closer to more realistic simulations. Thus, other effects, such as biological or chemical processes, may be mainly responsible for the enhanced radiosensibilization observed in biological studies. However, more biological studies are needed to verify this hypothesis.« less

The Effects of Inhaled Nickel Nanoparticles on Murine Endothelial Progenitor Cells

NASA Astrophysics Data System (ADS)

Liberda, Eric N.

Introduction. Particulate air pollution, specifically nickel found on or in particulate matter, has been associated with an increased risk of mortality in human population studies and can cause increases in vascular inflammation, generate reactive oxygen species, alter vasomotor tone, and potentiate atherosclerosis in murine exposures. With the discovery of endothelial progenitor cells (EPCs), a door has been opened which may explain these observed cardiovascular effects associated with inhaled air particles and nickel exposure. In order to further quantify the effects of inhaled nickel nanoparticles and attempt to elucidate how the observed findings from other studies may occur, several whole body inhalation exposure experiments to nickel nanoparticles were performed. Methods. Following whole body exposure to approximately 500mug/m3 of nickel nanoparticles for 5 hrs, bone marrow EPCs from C57BL/6 mice were isolated. EPCs were harvested for their RNA or used in a variety of assays including chemotaxis, tube formation, and proliferation. Gene expression was assessed for important receptors involved in EPC mobilization and homing using RT-PCR methods. EPCs, circulating endothelial progenitor cells, circulating endothelial cells (CECs), and endothelial microparticles (EMPs) were quantified on a BD FACSCalibur to examine endothelial damage and repair associated with the inhalation exposure. Plasma proteins were assessed using the 2D DIGE proteomic approach and commercially available ELISAs. Results and Conclusions. Exposure to inhaled nickel nanoparticles significantly increased both bone marrow EPCs as well as their levels in circulation. CECs were significantly upregulated suggesting that endothelial damage occurred due to the exposure. There was no significant difference in EMPs between the two groups. Tube formation and chemotaxis, but not proliferation, of bone marrow EPCs was impaired in the nickel nanoparticle exposed group. This decrease in EPC function coincided with downregulation of receptors for EPC mobilization and homing. Antioxidant plasma proteins were upregulated post-exposure and transferrin was downregulated. In conclusion, these results indicate that inhalation exposure to Ni nanoparticles below the current OSHA permissible exposure limit for Ni compounds can lead to alterations in bone marrow progenitor cells that may ultimately lead to the development of various cardiovascular diseases.

Infrared extinction and microwave absorption properties of hybrid Fe3O4@SiO2@Ag nanospheres synthesized via a facile seed-mediated growth route.

PubMed

Chen, Yongpeng; Li, Shichuan; Wei, Xuebin; Tang, Runze; Zhou, Zunning

2018-06-21

Fe3O4@SiO2@Ag ternary hybrid nanoparticles were synthesized via a facile seed-mediated growth route. X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) measurements were used to characterize the as-prepared product. The results indicated that the nanoparticles exhibited excellent magnetic properties and an extremely dense structure with Ag layer thicknesses of 30 nm, 40 nm, and 50 nm. Furthermore, the microwave shielding effectiveness exceeded 20 dB over almost the entire frequency range (2-18 GHz), and the effectiveness obviously improved as the thickness of the Ag layer increased. In addition, the IR extinction coefficient of the nanoparticles was calculated by a finite-difference time-domain (FDTD) method, which showed that the nanoparticles can inherit the extinction performance of pure silver when the Ag shell thickness was 30 nm. Specifically, after assembling into chains, the peak position of the IR extinction curves displayed a significant redshift and an intensity increase as the number of nanoparticles increased in the chain, which dramatically promoted the IR extinction capability. As a result, the Fe3O4@SiO2@Ag nanoparticles are expected to be used as a new multispectral interference material. © 2018 IOP Publishing Ltd.

Visualisation of distribution of gold nanoparticles in liver tissues ex vivo and in vitro using the method of optical coherence tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genina, Elina A; Terentyuk, G S; Khlebtsov, B N

2012-06-30

The possibility of visualising the distribution of gold nanoparticles in liver by means of the method of optical coherence tomography is studied experimentally in model samples of beef liver in vitro and rat liver ex vivo. In the experiments we used the gold nanoparticles in the form of nanocages with resonance absorption in the near-IR spectral region. In the model studies the suspension of nanoparticles was applied to the surface of the sample, which then was treated with ultrasound. In the ex vivo studies the suspension of nanoparticles was injected to the laboratory rats intravenously. The image contrast and themore » optical depth of detection of blood vessels and liver structure components are calculated, as well as the depth of liver optical probing before and after the injection of nanoparticles. It was shown that the administration of the nanoparticle increases significantly the imaging contrast of liver blood vessels owing to the localisation of the nanoparticles therein.« less

Interaction of lysozyme protein with different sized silica nanoparticles and their resultant structures

NASA Astrophysics Data System (ADS)

Yadav, Indresh; Aswal, V. K.; Kohlbrecher, J.

2016-05-01

The interaction of model protein-lysozyme with three different sized anionic silica nanoparticles has been studied by UV-vis spectroscopy, dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The surface area and curvature of the nanoparticles change with size, which significantly influence their interaction with protein. The lysozyme adsorbs on the surface of the nanoparticles due to electrostatic attraction and leads to the phase transformation from one phase (clear) to two-phase (turbid) of the nanoparticle-protein system. The dominance of lysozyme induced short-range attraction over long-range electrostatic repulsion between nanoparticles is responsible for phase transformation and modeled by the two-Yukawa potential. The magnitude of the attractive interaction increases with the size of the nanoparticles as a result the phase transformation commences relatively at lower concentration of lysozyme. The structure of the nanoparticle-protein system in two-phase is characterized by the diffusion limited aggregate type of mass fractal morphology.

Interaction of lysozyme protein with different sized silica nanoparticles and their resultant structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Indresh, E-mail: iykumarindresh288@gmail.com; Aswal, V. K.; Kohlbrecher, J.

The interaction of model protein-lysozyme with three different sized anionic silica nanoparticles has been studied by UV-vis spectroscopy, dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The surface area and curvature of the nanoparticles change with size, which significantly influence their interaction with protein. The lysozyme adsorbs on the surface of the nanoparticles due to electrostatic attraction and leads to the phase transformation from one phase (clear) to two-phase (turbid) of the nanoparticle-protein system. The dominance of lysozyme induced short-range attraction over long-range electrostatic repulsion between nanoparticles is responsible for phase transformation and modeled by the two-Yukawa potential. Themore » magnitude of the attractive interaction increases with the size of the nanoparticles as a result the phase transformation commences relatively at lower concentration of lysozyme. The structure of the nanoparticle-protein system in two-phase is characterized by the diffusion limited aggregate type of mass fractal morphology.« less

Mitochondrial dysfunction and loss of glutamate uptake in primary astrocytes exposed to titanium dioxide nanoparticles

NASA Astrophysics Data System (ADS)

Wilson, Christina L.; Natarajan, Vaishaali; Hayward, Stephen L.; Khalimonchuk, Oleh; Kidambi, Srivatsan

2015-11-01

Titanium dioxide (TiO2) nanoparticles are currently the second most produced engineered nanomaterial in the world with vast usage in consumer products leading to recurrent human exposure. Animal studies indicate significant nanoparticle accumulation in the brain while cellular toxicity studies demonstrate negative effects on neuronal cell viability and function. However, the toxicological effects of nanoparticles on astrocytes, the most abundant cells in the brain, have not been extensively investigated. Therefore, we determined the sub-toxic effect of three different TiO2 nanoparticles (rutile, anatase and commercially available P25 TiO2 nanoparticles) on primary rat cortical astrocytes. We evaluated some events related to astrocyte functions and mitochondrial dysregulation: (1) glutamate uptake; (2) redox signaling mechanisms by measuring ROS production; (3) the expression patterns of dynamin-related proteins (DRPs) and mitofusins 1 and 2, whose expression is central to mitochondrial dynamics; and (4) mitochondrial morphology by MitoTracker® Red CMXRos staining. Anatase, rutile and P25 were found to have LC50 values of 88.22 +/- 10.56 ppm, 136.0 +/- 31.73 ppm and 62.37 +/- 9.06 ppm respectively indicating nanoparticle specific toxicity. All three TiO2 nanoparticles induced a significant loss in glutamate uptake indicative of a loss in vital astrocyte function. TiO2 nanoparticles also induced an increase in reactive oxygen species generation, and a decrease in mitochondrial membrane potential, suggesting mitochondrial damage. TiO2 nanoparticle exposure altered expression patterns of DRPs at low concentrations (25 ppm) and apoptotic fission at high concentrations (100 ppm). TiO2 nanoparticle exposure also resulted in changes to mitochondrial morphology confirmed by mitochondrial staining. Collectively, our data provide compelling evidence that TiO2 nanoparticle exposure has potential implications in astrocyte-mediated neurological dysfunction.Titanium dioxide (TiO2) nanoparticles are currently the second most produced engineered nanomaterial in the world with vast usage in consumer products leading to recurrent human exposure. Animal studies indicate significant nanoparticle accumulation in the brain while cellular toxicity studies demonstrate negative effects on neuronal cell viability and function. However, the toxicological effects of nanoparticles on astrocytes, the most abundant cells in the brain, have not been extensively investigated. Therefore, we determined the sub-toxic effect of three different TiO2 nanoparticles (rutile, anatase and commercially available P25 TiO2 nanoparticles) on primary rat cortical astrocytes. We evaluated some events related to astrocyte functions and mitochondrial dysregulation: (1) glutamate uptake; (2) redox signaling mechanisms by measuring ROS production; (3) the expression patterns of dynamin-related proteins (DRPs) and mitofusins 1 and 2, whose expression is central to mitochondrial dynamics; and (4) mitochondrial morphology by MitoTracker® Red CMXRos staining. Anatase, rutile and P25 were found to have LC50 values of 88.22 +/- 10.56 ppm, 136.0 +/- 31.73 ppm and 62.37 +/- 9.06 ppm respectively indicating nanoparticle specific toxicity. All three TiO2 nanoparticles induced a significant loss in glutamate uptake indicative of a loss in vital astrocyte function. TiO2 nanoparticles also induced an increase in reactive oxygen species generation, and a decrease in mitochondrial membrane potential, suggesting mitochondrial damage. TiO2 nanoparticle exposure altered expression patterns of DRPs at low concentrations (25 ppm) and apoptotic fission at high concentrations (100 ppm). TiO2 nanoparticle exposure also resulted in changes to mitochondrial morphology confirmed by mitochondrial staining. Collectively, our data provide compelling evidence that TiO2 nanoparticle exposure has potential implications in astrocyte-mediated neurological dysfunction. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03646a

Nanoparticles can cause DNA damage across a cellular barrier

NASA Astrophysics Data System (ADS)

Bhabra, Gevdeep; Sood, Aman; Fisher, Brenton; Cartwright, Laura; Saunders, Margaret; Evans, William Howard; Surprenant, Annmarie; Lopez-Castejon, Gloria; Mann, Stephen; Davis, Sean A.; Hails, Lauren A.; Ingham, Eileen; Verkade, Paul; Lane, Jon; Heesom, Kate; Newson, Roger; Case, Charles Patrick

2009-12-01

The increasing use of nanoparticles in medicine has raised concerns over their ability to gain access to privileged sites in the body. Here, we show that cobalt-chromium nanoparticles (29.5 +/- 6.3 nm in diameter) can damage human fibroblast cells across an intact cellular barrier without having to cross the barrier. The damage is mediated by a novel mechanism involving transmission of purine nucleotides (such as ATP) and intercellular signalling within the barrier through connexin gap junctions or hemichannels and pannexin channels. The outcome, which includes DNA damage without significant cell death, is different from that observed in cells subjected to direct exposure to nanoparticles. Our results suggest the importance of indirect effects when evaluating the safety of nanoparticles. The potential damage to tissues located behind cellular barriers needs to be considered when using nanoparticles for targeting diseased states.

Nanoparticle-Reinforced Associative Network Hydrogels

PubMed Central

Agrawal, Sarvesh K.; Sanabria-DeLong, Naomi; Tew, Gregory N.; Bhatia, Surita R.

2009-01-01

ABA triblock copolymers in solvents selective for the midblock are known to form associative micellar gels. We have modified the structure and rheology of ABA triblock copolymer gels comprising poly(lactide)-poly(ethylene oxide)-poly(lactide) (PLA-PEO-PLA) through addition of a clay nanoparticle, laponite. Addition of laponite particles resulted in additional junction points in the gel via adsorption of the PEO corona chains onto the clay surfaces. Rheological measurements showed that this strategy led to a significant enhancement of the gel elastic modulus with small amounts of nanoparticles. Further characterization using SAXS and DLS confirmed that nanoparticles increase the intermicellar attraction and result in aggregation of PLA-PEO-PLA micelles. PMID:18947244

Effect of anisotropic MoS2 nanoparticles on the blue phase range of a chiral liquid crystal.

PubMed

Lavrič, Marta; Cordoyiannis, George; Kralj, Samo; Tzitzios, Vassilios; Nounesis, George; Kutnjak, Zdravko

2013-08-01

Liquid-crystalline blue phases are attracting significant interest due to their potential for applications related to tunable photonic crystals and fast optical displays. In this work a brief theoretical model is presented accounting for the impact of anisotropic nanoparticles on the blue phase stability region. This model is tested by means of high-resolution calorimetric and optical measurements of the effect of anisotropic, surface-functionalized MoS2 nanoparticles on the blue phase range of a chiral liquid crystal. The addition of these nanoparticles effectively increases the temperature range of blue phases and especially the cubic structure of blue phase I.

Laser thermal ablation of multidrug-resistant bacteria using functionalized gold nanoparticles

PubMed Central

Mocan, Lucian; Tabaran, Flaviu A; Mocan, Teodora; Pop, Teodora; Mosteanu, Ofelia; Agoston-Coldea, Lucia; Matea, Cristian T; Gonciar, Diana; Zdrehus, Claudiu; Iancu, Cornel

2017-01-01

The issue of multidrug resistance (MDR) has become an increasing threat to public health. One alternative strategy against MDR bacteria would be to construct therapeutic vectors capable of physically damaging these microorganisms. Gold nanoparticles hold great promise for the development of such therapeutic agents, since the nanoparticles exhibit impressive properties, of which the most important is the ability to convert light into heat. This property has scientific significance since is exploited to develop nano-photothermal vectors to destroy bacteria at a molecular level. The present paper summarizes the latest advancements in the field of nanotargeted laser hyperthermia of MDR bacteria mediated by gold nanoparticles. PMID:28356741

Natural lipid nanoparticles containing nimesulide: synthesis, characterization and in vivo antiedematogenic and antinociceptive activities.

PubMed

Raffin, Renata P; Lima, Amanda; Lorenzoni, Ricardo; Antonow, Michelli B; Turra, Cláudia; Alves, Marta P; Fagan, Solange B

2012-04-01

Lipid nanoparticles are drug delivery systems able to increase bioavailability of poorly soluble drugs. They can be prepared with different lipid materials, especially natural lipids. Shea butter is a natural lipid obtained from the Butyrospermum parkii seed and rich in oleic and stearic acids. Nimesulide is a COX 2 selective anti-inflammatory that is poorly soluble in water. The purpose of this study was to develop and characterize shea butter lipid nanoparticles using a new technique and evaluate the in vivo activity of these nanoparticles. Lipid nanoparticles were prepared by melting shea butter and mixing with an aqueous phase using a high shear mixer. The nanoparticles presented pH of 6.9 +/- 0.1, mean particle size of 90 nm and a narrow polydispersity (0.21). Zeta potential was around -20 mV and the encapsulation efficiency was 97.5%. Drug release was evaluated using dialysis bags and presented monoexponential profile with t50% of 4.80 h (free drug t50% was only 2.86 h). Antinociceptive activity was performed by the acetic acid model. Both nimesulide and nimesulide-loaded nanoparticles presented significant activity compared to the control. The in vivo anti-inflammatory activity was evaluated by paw edema and was statistically different for the nanoparticles containing nimesulide compared to free nimesulide, blank nanoparticles and saline. In conclusion, the use of shea butter as encapsulating lipid was very successful and allowed nanoparticles to be prepared with a very simple technique. The nanoparticles presented significant pharmacological effects that were not seen for free drug administration.

Effect of cobalt doping on crystallinity, stability, magnetic and optical properties of magnetic iron oxide nano-particles

NASA Astrophysics Data System (ADS)

Anjum, Safia; Tufail, Rabia; Rashid, Khalid; Zia, Rehana; Riaz, S.

2017-06-01

This paper is dedicated to investigate the effect of Co2+ ions in magnetite Fe3O4 nano-particles with stoichiometric formula CoxFe3-xO4 where (x = 0, 0.05, 0.1 and 0.15) prepared by co-precipitation method. The structural, thermal, morphological, magnetic and optical properties of magnetite and Co2+ doped magnetite nanoparticles have been carried out using X-ray Diffractometer, Fourier Transform Infrared Spectroscopy, Themogravimetric Analysis, Scanning Electron Microscopy, Vibrating Sample Magnetometer (VSM) and UV-Vis Spectrometer (UV-Vis) respectively. Structural analysis verified the formation of single phase inverse spinel cubic structure with decrease in lattice parameters due to increase in cobalt content. FTIR analysis confirms the single phase of CoxFe3-xO4 nanoparticles with the major band at 887 cm-1, which might be due to the stretching vibrations of metal-oxide bond. The DSC results corroborate the finding of an increase in the maghemite to hematite phase transition temperature with increase in Co2+ content. The decrease in enthalpy with increase in Co2+ concentration attributed to the fact that the degree of conversion from maghemite to hematite decrease which shows that the stability increases with increasing Co2+ content in B-site of Fe3O4 structure. SEM analysis demonstrated the formation of spherical shaped nanoparticles with least agglomeration. The magnetic measurements enlighten that the coercivity and anisotropy of CoxFe3-xO4 nanoparticles are significantly increased. From UV-Vis analysis it is revealed that band gap energy increases with decreasing particle size. This result has a great interest for magnetic fluid hyperthermia application (MPH).

A tissue factor-cascade-targeted strategy to tumor vasculature: a combination of EGFP-EGF1 conjugation nanoparticles with photodynamic therapy.

PubMed

Shi, Wei; Yin, Yanxue; Wang, Yao; Zhang, Bo; Tan, Pei; Jiang, Ting; Mei, Heng; Deng, Jun; Wang, Huafang; Guo, Tao; Pang, Zhiqing; Hu, Yu

2017-05-09

Tumor requires tumor vasculature to supply oxygen and nutrients so as to support its continued growth, as well as provide a main route for metastatic spread. In this study, a TF-cascade-targeted strategy aiming to disrupt tumor blood vessels was developed by combination of TF-targeted HMME-loaded drug delivery system and PDT. PDT is a promising new modality in the treatment of cancers, which employs the interaction between a tumor-localizing photosensitizer and light of an appropriate wavelength to bring about ROS-induced cell death. In vitro results showed that protein EGFP-EGF1modification could significantly contribute to the uptake of nanoparticles by TF over-expressed BCECs. In vivo multispectral fluorescent imaging, the EGFP-EGF1 conjugated nanoparticles showed significantly higher accumulation in tumor tissues than non-conjugated ones. Tumor tissue slides further presented that EGFP-EGF1 conjugated nanoparticles showed significantly higher accumulation in tumor vasculature than non-conjugated ones. In vitro study demonstrated that PDT increased TF expression of BCECs. In vivo imaging, ex vivo imaging and tumor tissue slides showed that PDT further contribute EGFP-EGF1-NP accumulation in tumor. These promising results indicated that PDT enhanced EGFP-EGF1modified PEG-PLGA nanoparticle accumulation in tumor vaculature. Considering that EGFP-EGF1 conjugation enhanced nanoparticles uptake by TF over-expressed endothelium and PDT increased endothelium TF expression. We conclude that PDT triggered a TF cascade targeted effect. A combination of both EGFP-EGF1 modification and PDT provided a positive feed-back target effect to tumor vessels and might have a great potential for tumor therapy.

In vivo uptake and acute immune response to orally administered chitosan and PEG coated PLGA nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semete, B., E-mail: Bsemete@csir.co.z; Booysen, L.I.J.; Department of Pharmaceutics, North-West University, Potchefstroom Campus, Potchefstroom, 2520

2010-12-01

Nanoparticulate drug delivery systems offer great promise in addressing challenges of drug toxicity, poor bioavailability and non-specificity for a number of drugs. Much progress has been reported for nano drug delivery systems for intravenous administration, however very little is known about the effects of orally administered nanoparticles. Furthermore, the development of nanoparticulate systems necessitates a thorough understanding of the biological response post exposure. This study aimed to elucidate the in vivo uptake of chitosan and polyethylene glycol (PEG) coated Poly, DL, lactic-co-glycolic Acid (PLGA) nanoparticles and the immunological response within 24 h of oral and peritoneal administration. These PLGA nanoparticlesmore » were administered orally and peritoneally to female Balb/C mice, they were taken up by macrophages of the peritoneum. When these particles were fluorescently labelled, intracellular localisation was observed. The expression of pro-inflammatory cytokines IL-2, IL-6, IL-12p70 and TNF-{alpha} in plasma and peritoneal lavage was found to remain at low concentration in PLGA nanoparticles treated mice as well as ZnO nanoparticles during the 24 hour period. However, these were significantly increased in lipopolysaccharide (LPS) treated mice. Of these pro-inflammatory cytokines, IL-6 and IL-12p70 were produced at the highest concentration in the positive control group. The anti-inflammatory cytokines IL-10 and chemokines INF-{gamma}, IL-4, IL-5 remained at normal levels in PLGA treated mice. IL-10 and INF-{gamma} were significantly increased in LPS treated mice. MCP-1 was found to be significantly produced in all groups in the first hours, except the saline treated mice. These results provide the first report to detail the induction of cytokine production by PLGA nanoparticles engineered for oral applications.« less

Preparation and near-infrared photothermal conversion property of cesium tungsten oxide nanoparticles

PubMed Central

2013-01-01

Cs0.33WO3 nanoparticles have been prepared successfully by a stirred bead milling process. By grinding micro-sized coarse powder with grinding beads of 50 μm in diameter, the mean hydrodynamic diameter of Cs0.33WO3 powder could be reduced to about 50 nm in 3 h, and a stable aqueous dispersion could be obtained at pH 8 via electrostatic repulsion mechanism. After grinding, the resulting Cs0.33WO3 nanoparticles retained the hexagonal structure and had no significant contaminants from grinding beads. Furthermore, they exhibited a strong characteristic absorption and an excellent photothermal conversion property in the near-infrared (NIR) region, owing to the free electrons or polarons. Also, the NIR absorption and photothermal conversion property became more significant with decreasing particle size or increasing particle concentration. When the concentration of Cs0.33WO3 nanoparticles was 0.08 wt.%, the solution temperature had a significant increase of above 30°C in 10 min under NIR irradiation (808 nm, 2.47 W/cm2). In addition, they had a photothermal conversion efficiency of about 73% and possessed excellent photothermal stability. Such an effective NIR absorption and photothermal conversion nanomaterial not only was useful in the NIR shielding, but also might find great potential in biomedical application. PMID:23379652

Estradiol-loaded PLGA nanoparticles for improving low bone mineral density of cancellous bone caused by osteoporosis: Application of enhanced charged nanoparticles with iontophoresis.

PubMed

Takeuchi, Issei; Kobayashi, Shiori; Hida, Yukari; Makino, Kimiko

2017-07-01

Postmenopausal osteoporosis among older women, which occurs by an ovarian hormone deficiency, is one of the major public health problems. 17 β-estradiol (E2) is used to prevent and treat this disease as a drug of hormone replacement therapy. In oral administration, E2 is significantly affected by first-pass hepatic metabolism, and high dose administration must be needed to obtain drug efficacy. Therefore, alternative administration route is needed, and we have focused on the transdermal drug delivery system. In this study, we have prepared E2-loaded poly(DL-lactide-co-glycolide) (PLGA) nanoparticles for osteoporosis by using a combination of an antisolvent diffusion method with preferential solvation. The average particle diameter of the nanoparticles was 110.0±41.0nm and the surface charge number density was 82 times higher than that of conventional E2-loaded PLGA nanoparticles. Therapeutic evaluation of E2-loaded PLGA nanoparticles was carried out using ovariectomized female rats. Therapeutic efficacy was evaluated to measure bone mineral density of cancellous bone using an X-ray CT system. When the E2-loaded PLGA nanoparticles were administrated once a week, bone mineral density was significantly higher than that of the non-treated group at 60days after the start of treatment. Also, in the group administered this nanoparticle twice a week, the bone mineral density increased significantly at 45days after the start of treatment. From these results, it was revealed that E2-loaded PLGA nanoparticles with iontophoresis were useful to recover bone mineral density of cancellous bone, and it was also suggested that they extend the dosing interval of E2. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of morphological and functional changes in organs of rats after intramuscular introduction of iron nanoparticles and their agglomerates.

PubMed

Sizova, Elena; Miroshnikov, Sergey; Yausheva, Elena; Polyakova, Valentina

2015-01-01

The research was performed on male Wistar rats based on assumptions that new microelement preparations containing metal nanoparticles and their agglomerates had potential. Morphological and functional changes in tissues in the injection site and dynamics of chemical element metabolism (25 indicators) in body were assessed after repeated intramuscular injections (total, 7) with preparation containing agglomerate of iron nanoparticles. As a result, iron depot was formed in myosymplasts of injection sites. The quantity of muscle fibers having positive Perls' stain increased with increasing number of injections. However, the concentration of the most chemical elements and iron significantly decreased in the whole skeletal muscle system (injection sites are not included). Consequently, it increased up to the control level after the sixth and the seventh injections. Among the studied organs (liver, kidneys, and spleen), Caspase-3 expression was revealed only in spleen. The expression had a direct dependence on the number of injections. Processes of iron elimination from preparation containing nanoparticles and their agglomerates had different intensity.

Soil microbial community responses to contamination with silver, aluminium oxide and silicon dioxide nanoparticles.

PubMed

McGee, C F; Storey, S; Clipson, N; Doyle, E

2017-04-01

Soil microorganisms are key contributors to nutrient cycling and are essential for the maintenance of healthy soils and sustainable agriculture. Although the antimicrobial effects of a broad range of nanoparticulate substances have been characterised in vitro, little is known about the impact of these compounds on microbial communities in environments such as soil. In this study, the effect of three widely used nanoparticulates (silver, silicon dioxide and aluminium oxide) on bacterial and fungal communities in an agricultural pastureland soil was examined in a microcosm-based experiment using a combination of enzyme analysis, molecular fingerprinting and amplicon sequencing. A relatively low concentration of silver nanoparticles (AgNPs) significantly reduced total soil dehydrogenase and urease activity, while Al 2 O 3 and SiO 2 nanoparticles had no effect. Amplicon sequencing revealed substantial shifts in bacterial community composition in soils amended with AgNPs, with significant decreases in the relative abundance of Acidobacteria and Verrucomicrobia and an increase in Proteobacteria. In particular, the relative abundance of the Proteobacterial genus Dyella significantly increased in AgNP amended soil. The effects of Al 2 O 3 and SiO 2 NPs on bacterial community composition were less pronounced. AgNPs significantly reduced bacterial and archaeal amoA gene abundance in soil, with the archaea more susceptible than bacteria. AgNPs also significantly impacted soil fungal community structure, while Al 2 O 3 and SiO 2 NPs had no effect. Several fungal ribotypes increased in soil amended with AgNPs, compared to control soil. This study highlights the need to consider the effects of individual nanoparticles on soil microbial communities when assessing their environmental impact.

Engineering novel targeted nanoparticle formulations to increase the therapeutic efficacy of conventional chemotherapeutics against multiple myeloma

NASA Astrophysics Data System (ADS)

Ashley, Jonathan D.

Multiple myeloma (MM) is a hematological malignancy which results from the uncontrolled clonal expansion of plasma cells within the body. Despite recent medical advances, this disease remains largely incurable, with a median survival of ˜7 years, owing to the development of drug resistance. This dissertation will explore new advances in nanotechnology that will combine the cytotoxic effects of small molecule chemotherapeutics with the tumor targeting capabilities of nanoparticles to create novel nanoparticle formulations that exhibit enhanced therapeutic indices in the treatment of MM. First, doxorubicin was surfaced conjugated onto micellar nanoparticles via an acid labile hydrazone bond to increase the drug accumulation at the tumor. The cell surface receptor Very Late Antigen-4 (VLA-4; alpha4beta1) is expressed on cancers of hematopoietic origin and plays a vital role in the cell adhesion mediated drug resistance (CAM-DR) in MM. Therefore, VLA-4 antagonist peptides were conjugated onto the nanoparticles via a multifaceted procedure to actively target MM cells and simultaneously inhibit CAM-DR. The micellar doxorubicin nanoparticles were able to overcome CAM-DR and demonstrated improved therapeutic index relative to free doxorubicin. In addition to doxorubicin, other classes of therapeutic agents, such as proteasome inhibitors, can be incorporated in nanoparticles for improved therapeutic outcomes. Utilizing boronic acid chemistry, bortezomib prodrugs were synthesized using a reversible boronic ester bond and then incorporated into liposomes. The different boronic ester bonds that could be potentially used in the synthesis of bortezomib prodrugs were screened based on stability using isobutylboronic acid. The liposomal bortezomib nanoparticles demonstrated significant proteasome inhibition and cytotoxicity in MM cells in vitro, and dramatically reduced the non-specific toxicities associated with free bortezomib while maintaining significant tumor growth inhibition in vivo. Carfilzomib, another proteasome inhibitor, was embedded into the lipid bilayer of liposomes to improve its therapeutic efficacy. VLA-4 antagonist peptides were also incorporated to facilitate MM cell targeting and uptake. The liposomal carfilzomib nanoparticles demonstrated improved therapeutic index and synergy with doxorubicin compared to free carfilzomib. These nanoparticle formulations can significantly improve the efficacy of the respective therapeutic agents and have an immense potential to positively impact the treatment of MM providing for improved patient outcomes.

Foam, a promising vehicle to deliver nanoparticles for vadose zone remediation.

PubMed

Shen, Xin; Zhao, Lin; Ding, Yuanzhao; Liu, Bo; Zeng, Hui; Zhong, Lirong; Li, Xiqing

2011-02-28

Foam delivery of remedial amendments for in situ immobilization of deep vadose zone contaminants can overcome the intrinsic problems associated with solution-based delivery, such as preferential flow and contaminant mobilization. In this work, the feasibility of using foam to deliver nanoparticles in unsaturated porous media was investigated. Carboxyl-modified polystyrene latex microspheres were used as surrogates for nanoparticles of remediation purposes. Foams generated from the solutions of six commonly available surfactants all had excellent abilities to carry the microspheres. The presence of the microspheres did not reduce the stabilities of the foams. When microsphere-laden foam was injected through the unsaturated columns, the fractions of microspheres exiting the column were much higher than that when the microsphere water suspensions were injected through the columns. The enhanced microsphere transport implies that foam delivery could significantly increase the radius of influence of injected nanoparticles of remediation purposes. Reduced tension at air-water interfaces by the surfactant and increased driving forces imparted on the microspheres at the interfaces by the flowing foam bubbles may have both contributed to the enhanced transport. Preliminary tests also demonstrated that foam can carry significant fractions of zero valent iron nanoparticles at concentrations relevant to field remediation conditions (up to 5.3 g L(-1)). As such, this study demonstrates that surfactant foam is potentially a promising vehicle to deliver nanoparticles for vadose zone remediation. Copyright © 2010 Elsevier B.V. All rights reserved.

Kinetics and pathogenesis of intracellular magnetic nanoparticle cytotoxicity

NASA Astrophysics Data System (ADS)

Giustini, Andrew J.; Gottesman, Rachel E.; Petryk, A. A.; Rauwerdink, A. M.; Hoopes, P. Jack

2011-03-01

Magnetic nanoparticles excited by alternating magnetic fields (AMF) have demonstrated effective tumor-specific hyperthermia. This treatment is effective as a monotherapy as well as a therapeutic adjuvant to chemotherapy and radiation. Iron oxide nanoparticles have been shown, so far, to be non-toxic, as are the exciting AMF fields when used at moderate levels. Although higher levels of AMF can be more effective, depending on the type of iron oxide nanoparticles use, these higher field strengths and/or frequencies can induce normal tissue heating and toxicity. Thus, the use of nanoparticles exhibiting significant heating at low AMF strengths and frequencies is desirable. Our preliminary experiments have shown that the aggregation of magnetic nanoparticles within tumor cells improves their heating effect and cytotoxicity per nanoparticle. We have used transmission electron microscopy to track the endocytosis of nanoparticles into tumor cells (both breast adenocarcinoma (MTG-B) and acute monocytic leukemia (THP-1) cells). Our preliminary results suggest that nanoparticles internalized into tumor cells demonstrate greater cytotoxicity when excited with AMF than an equivalent heat dose from excited external nanoparticles or cells exposed to a hot water bath. We have also demonstrated that this increase in SAR caused by aggregation improves the cytotoxicity of nanoparticle hyperthermia therapy in vitro.

Facile integration of multiple magnetite nanoparticles for theranostics combining efficient MRI and thermal therapy

NASA Astrophysics Data System (ADS)

Huang, Guoming; Zhu, Xianglong; Li, Hui; Wang, Lirong; Chi, Xiaoqin; Chen, Jiahe; Wang, Xiaomin; Chen, Zhong; Gao, Jinhao

2015-01-01

Multifunctional nanostructures with both diagnostic and therapeutic capabilities have attracted considerable attention in biomedical research because they can offer great advantages in disease management and prognosis. In this work, a facile way to transfer the hydrophobic iron oxide (IO) nanoparticles into aqueous media by employing carboxylic graphene oxide (GO-COOH) as the transferring agent has been reported. In this one-step process, IO nanoparticles adhere to GO-COOH and form water-dispersible clusters via hydrophobic interactions between the hydrophobic ligands of IO nanoparticles and the basal plane of GO-COOH. The multiple IO nanoparticles on GO-COOH sheets (IO/GO-COOH) present a significant increase in T2 contrast enhancement. Moreover, the IO/GO-COOH nanoclusters also display a high photothermal conversion efficiency and can effectively inhibit tumor growth through the photothermal effects. It is envisioned that such IO/GO-COOH nanocomposites combining efficient MRI and photothermal therapy hold great promise in theranostic applications.Multifunctional nanostructures with both diagnostic and therapeutic capabilities have attracted considerable attention in biomedical research because they can offer great advantages in disease management and prognosis. In this work, a facile way to transfer the hydrophobic iron oxide (IO) nanoparticles into aqueous media by employing carboxylic graphene oxide (GO-COOH) as the transferring agent has been reported. In this one-step process, IO nanoparticles adhere to GO-COOH and form water-dispersible clusters via hydrophobic interactions between the hydrophobic ligands of IO nanoparticles and the basal plane of GO-COOH. The multiple IO nanoparticles on GO-COOH sheets (IO/GO-COOH) present a significant increase in T2 contrast enhancement. Moreover, the IO/GO-COOH nanoclusters also display a high photothermal conversion efficiency and can effectively inhibit tumor growth through the photothermal effects. It is envisioned that such IO/GO-COOH nanocomposites combining efficient MRI and photothermal therapy hold great promise in theranostic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06616b

Enhancement of Dose Response and Nuclear Magnetic Resonance Image of PAGAT Polymer Gel Dosimeter by Adding Silver Nanoparticles

PubMed Central

Sabbaghizadeh, Rahim; Shamsudin, Roslinda; Deyhimihaghighi, Najmeh; Sedghi, Arman

2017-01-01

In the present study, the normoxic polyacrylamide gelatin and tetrakis hydroxy methyl phosphoniun chloride (PAGAT) polymer gel dosimeters were synthesized with and without the presence of silver (Ag) nanoparticles. The amount of Ag nanoparticles varied from 1 to 3 ml with concentration 3.14 g/l, thus forming two types of PAGAT polymer gel dosimeters before irradiating them with 6 to 25 Gy produced by 1.25-MeV 60Co gamma rays. In this range, the predominant gamma ray interaction with matter is by Compton scattering effect, as the photoelectric absorption effect diminishes. MRI was employed when evaluating the polymerization of the dosimeters and the gray scale of the MRI film was determined via an optical densitometer. Subsequent analyses of optical densities revealed that the extent of polymerization increased with the increase in the absorbed dose, while the increase of penetration depth within the dosimeters has a reverse effect. Moreover, a significant increase in the optical density-dose response (11.82%) was noted for dosimeters containing 2 ml Ag nanoparticles. PMID:28060829

Nanoparticles Engineered from Lecithin-in-Water Emulsions As A Potential Delivery System for Docetaxel

PubMed Central

Yanasarn, Nijaporn; Sloat, Brian R.; Cui, Zhengrong

2009-01-01

Docetaxel is a potent anti-cancer drug. However, there continues to be a need for alternative docetaxel delivery systems to improve its efficacy. We reported the engineering of a novel spherical nanoparticle formulation (~270 nm) from lecithin-in-water emulsions. Docetaxel can be incorporated into the nanoparticles, and the resultant docetaxel-nanoparticles were stable when stored as an aqueous suspension. The release of the docetaxel from the nanoparticles was likely caused by a combination of diffusion and Case II transport. The docetaxel-in-nanoparticles were more effective in killing tumor cells in culture than free docetaxel. Moreover, the docetaxel-nanoparticles did not cause any significant red blood cell lysis or platelet aggregation in vitro, nor did they induce detectable acute liver damage when injected intravenously into mice. Finally, compared to free docetaxel, the intravenously injected docetaxel-nanoparticles increased the accumulation of the docetaxel in a model tumor in mice by 4.5-fold. These lecithin-based nanoparticles have the potential to be a novel biocompatible and efficacious delivery system for docetaxel. PMID:19524029

TiO2 nanoparticle-induced ROS correlates with modulated immune cell function

NASA Astrophysics Data System (ADS)

Maurer-Jones, Melissa A.; Christenson, Jenna R.; Haynes, Christy L.

2012-12-01

Design of non-toxic nanoparticles will be greatly facilitated by understanding the nanoparticle-cell interaction mechanism on a cell function level. Mast cells are important cells for the immune system's first line of defense, and we can utilize their exocytotic behavior as a model cellular function as it is a conserved process across cell types and species. Perturbations in exocytosis can also have implications for whole organism health. One proposed mode of toxicity is nanoparticle-induced reactive oxygen species (ROS), particularly for titanium dioxide (TiO2) nanoparticles. Herein, we have correlated changes in ROS with the perturbation of the critical cell function of exocytosis, using UV light to induce greater levels of ROS in TiO2 exposed cells. The primary culture mouse peritoneal mast cells (MPMCs) were exposed to varying concentrations of TiO2 nanoparticles for 24 h. ROS content was determined using 2,7-dihydrodichlorofluorescein diacetate (DCFDA). Cellular viability was determined with the MTT and Trypan blue assays, and exocytosis was measured by the analytical electrochemistry technique of carbon-fiber microelectrode amperometry. MPMCs exposed to TiO2 nanoparticles experienced a dose-dependent increase in total ROS content. While there was minimal impact of ROS on cellular viability, there is a correlation between ROS amount and exocytosis perturbation. As nanoparticle-induced ROS increases, there is a significant decrease (45 %) in the number of serotonin molecules being released during exocytosis, increase (26 %) in the amount of time for each exocytotic granule to release, and decrease (28 %) in the efficiency of granule trafficking and docking. This is the first evidence that nanoparticle-induced ROS correlates with chemical messenger molecule secretion, possibly making a critical connection between functional impairment and mechanisms contributing to that impairment.

Biodistribution of indocyanine green-loaded nanoparticles with surface modifications of PEG and folic acid.

PubMed

Ma, Ying; Sadoqi, Mostafa; Shao, Jun

2012-10-15

To establish the biodistribution profile of the PLGA nanoparticles with dual surface modifications of PEG and folic acid (FA) in mice xenografted with MDA-MB-231 human breast cancer cells with high expression of folate receptor (FR); and to illustrate that the modified nanoparticles can target the loaded indocyanine green (ICG) to the tumor with high FR expression. ICG-loaded nanoparticles were prepared with PLGA (non-modified nanoparticles, NM-NP) or mPEG-PLGA and FA-PLGA (dual modified nanoparticles, DM-NP). Biodistribution of the ICG-loaded nanoparticles (1.25 mg/kg) after i.v. injection was investigated on athymic mice transplanted with MDA-MB-231 tumor. ICG concentration in plasma from the DM-NP group was significantly (p<0.05) higher than the NM-NP group from 90 min to the end of the study (12 h). After 4 h, the drug concentration in the tumor tissue from the DM-NP started to be significantly (p<0.05) higher than the NM-NP until 12 h. Compared to the NM-NP, the DM-NP increased the AUC(0-12 h) in plasma by 245% and the AUC(0-12 h) in tumor by 194%, while decreased the AUC(0-12 h) in liver by 13%. The accumulation of DM-NP into the tumor was significantly higher than NM-NP due to the long circulation and FR-mediated uptake. Copyright © 2012 Elsevier B.V. All rights reserved.

Oxidative stress mediated cytotoxicity of biologically synthesized silver nanoparticles in human lung epithelial adenocarcinoma cell line

NASA Astrophysics Data System (ADS)

Han, Jae Woong; Gurunathan, Sangiliyandi; Jeong, Jae-Kyo; Choi, Yun-Jung; Kwon, Deug-Nam; Park, Jin-Ki; Kim, Jin-Hoi

2014-09-01

The goal of the present study was to investigate the toxicity of biologically prepared small size of silver nanoparticles in human lung epithelial adenocarcinoma cells A549. Herein, we describe a facile method for the synthesis of silver nanoparticles by treating the supernatant from a culture of Escherichia coli with silver nitrate . The formation of silver nanoparticles was characterized using various analytical techniques. The results from UV-visible (UV-vis) spectroscopy and X-ray diffraction analysis show a characteristic strong resonance centered at 420 nm and a single crystalline nature, respectively. Fourier transform infrared spectroscopy confirmed the possible bio-molecules responsible for the reduction of silver from silver nitrate into nanoparticles. The particle size analyzer and transmission electron microscopy results suggest that silver nanoparticles are spherical in shape with an average diameter of 15 nm. The results derived from in vitro studies showed a concentration-dependent decrease in cell viability when A549 cells were exposed to silver nanoparticles. This decrease in cell viability corresponded to increased leakage of lactate dehydrogenase (LDH), increased intracellular reactive oxygen species generation (ROS), and decreased mitochondrial transmembrane potential (MTP). Furthermore, uptake and intracellular localization of silver nanoparticles were observed and were accompanied by accumulation of autophagosomes and autolysosomes in A549 cells. The results indicate that silver nanoparticles play a significant role in apoptosis. Interestingly, biologically synthesized silver nanoparticles showed more potent cytotoxicity at the concentrations tested compared to that shown by chemically synthesized silver nanoparticles. Therefore, our results demonstrated that human lung epithelial A549 cells could provide a valuable model to assess the cytotoxicity of silver nanoparticles.

Oxidative stress mediated cytotoxicity of biologically synthesized silver nanoparticles in human lung epithelial adenocarcinoma cell line

PubMed Central

2014-01-01

The goal of the present study was to investigate the toxicity of biologically prepared small size of silver nanoparticles in human lung epithelial adenocarcinoma cells A549. Herein, we describe a facile method for the synthesis of silver nanoparticles by treating the supernatant from a culture of Escherichia coli with silver nitrate. The formation of silver nanoparticles was characterized using various analytical techniques. The results from UV-visible (UV-vis) spectroscopy and X-ray diffraction analysis show a characteristic strong resonance centered at 420 nm and a single crystalline nature, respectively. Fourier transform infrared spectroscopy confirmed the possible bio-molecules responsible for the reduction of silver from silver nitrate into nanoparticles. The particle size analyzer and transmission electron microscopy results suggest that silver nanoparticles are spherical in shape with an average diameter of 15 nm. The results derived from in vitro studies showed a concentration-dependent decrease in cell viability when A549 cells were exposed to silver nanoparticles. This decrease in cell viability corresponded to increased leakage of lactate dehydrogenase (LDH), increased intracellular reactive oxygen species generation (ROS), and decreased mitochondrial transmembrane potential (MTP). Furthermore, uptake and intracellular localization of silver nanoparticles were observed and were accompanied by accumulation of autophagosomes and autolysosomes in A549 cells. The results indicate that silver nanoparticles play a significant role in apoptosis. Interestingly, biologically synthesized silver nanoparticles showed more potent cytotoxicity at the concentrations tested compared to that shown by chemically synthesized silver nanoparticles. Therefore, our results demonstrated that human lung epithelial A549 cells could provide a valuable model to assess the cytotoxicity of silver nanoparticles. PMID:25242904

Preparation of Transparent Bulk TiO2/PMMA Hybrids with Improved Refractive Indices via an in Situ Polymerization Process Using TiO2 Nanoparticles Bearing PMMA Chains Grown by Surface-Initiated Atom Transfer Radical Polymerization.

PubMed

Maeda, Satoshi; Fujita, Masato; Idota, Naokazu; Matsukawa, Kimihiro; Sugahara, Yoshiyuki

2016-12-21

Transparent TiO 2 /PMMA hybrids with a thickness of 5 mm and improved refractive indices were prepared by in situ polymerization of methyl methacrylate (MMA) in the presence of TiO 2 nanoparticles bearing poly(methyl methacrylate) (PMMA) chains grown using surface-initiated atom transfer radical polymerization (SI-ATRP), and the effect of the chain length of modified PMMA on the dispersibility of modified TiO 2 nanoparticles in the bulk hybrids was investigated. The surfaces of TiO 2 nanoparticles were modified with both m-(chloromethyl)phenylmethanoyloxymethylphosphonic acid bearing a terminal ATRP initiator and isodecyl phosphate with a high affinity for common organic solvents, leading to sufficient dispersibility of the surface-modified particles in toluene. Subsequently, SI-ATRP of MMA was achieved from the modified surfaces of the TiO 2 nanoparticles without aggregation of the nanoparticles in toluene. The molecular weights of the PMMA chains cleaved from the modified TiO 2 nanoparticles increased with increases in the prolonging of the polymerization period, and these exhibited a narrow distribution, indicating chain growth controlled by SI-ATRP. The nanoparticles bearing PMMA chains were well-dispersed in MMA regardless of the polymerization period. Bulk PMMA hybrids containing modified TiO 2 nanoparticles with a thickness of 5 mm were prepared by in situ polymerization of the MMA dispersion. The transparency of the hybrids depended significantly on the chain length of the modified PMMA on the nanoparticles, because the modified PMMA of low molecular weight induced aggregation of the TiO 2 nanoparticles during the in situ polymerization process. The refractive indices of the bulk hybrids could be controlled by adjusting the TiO 2 content and could be increased up to 1.566 for 6.3 vol % TiO 2 content (1.492 for pristine PMMA).

Absorption Study of Genistein Using Solid Lipid Microparticles and Nanoparticles: Control of Oral Bioavailability by Particle Sizes.

PubMed

Kim, Jeong Tae; Barua, Sonia; Kim, Hyeongmin; Hong, Seong-Chul; Yoo, Seung-Yup; Jeon, Hyojin; Cho, Yeongjin; Gil, Sangwon; Oh, Kyungsoo; Lee, Jaehwi

2017-07-01

In this study, the effect of particle size of genistein-loaded solid lipid particulate systems on drug dissolution behavior and oral bioavailability was investigated. Genistein-loaded solid lipid microparticles and nanoparticles were prepared with glyceryl palmitostearate. Except for the particle size, other properties of genistein-loaded solid lipid microparticles and nanoparticles such as particle composition and drug loading efficiency and amount were similarly controlled to mainly evaluate the effect of different particle sizes of the solid lipid particulate systems on drug dissolution behavior and oral bioavailability. The results showed that genistein-loaded solid lipid microparticles and nanoparticles exhibited a considerably increased drug dissolution rate compared to that of genistein bulk powder and suspension. The microparticles gradually released genistein as a function of time while the nanoparticles exhibited a biphasic drug release pattern, showing an initial burst drug release, followed by a sustained release. The oral bioavailability of genistein loaded in solid lipid microparticles and nanoparticles in rats was also significantly enhanced compared to that in bulk powders and the suspension. However, the bioavailability from the microparticles increased more than that from the nanoparticles mainly because the rapid drug dissolution rate and rapid absorption of genistein because of the large surface area of the genistein-solid lipid nanoparticles cleared the drug to a greater extent than the genistein-solid lipid microparticles did. Therefore, the findings of this study suggest that controlling the particle size of solid-lipid particulate systems at a micro-scale would be a promising strategy to increase the oral bioavailability of genistein.

Cytotoxicity of TiO{sub 2} nanoparticles towards freshwater sediment microorganisms at low exposure concentrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumari, Jyoti; Kumar, Deepak; Mathur, Ankita

2014-11-15

There is a persistent need to assess the effects of TiO{sub 2} nanoparticles on the aquatic ecosystem owing to their increasing usage in consumer products and risk of environmental release. The current study is focused on TiO{sub 2} nanoparticle-induced acute toxicity at sub-ppm level (≤1 ppm) on the three different freshwater sediment bacterial isolates and their consortium under two different irradiation (visible light and dark) conditions. The consortium of the bacterial isolates was found to be less affected by the exposure to the nanoparticles compared to the individual cells. The oxidative stress contributed considerably towards the cytotoxicity under both lightmore » and dark conditions. A statistically significant increase in membrane permeability was noted under the dark conditions as compared to the light conditions. The optical and fluorescence microscopic images showed aggregation and chain formation of the bacterial cells, when exposed to the nanoparticles. The electron microscopic (SEM, TEM) observations suggested considerable damage of cells and bio-uptake of nanoparticles. The exopolysaccrides (EPS) production and biofilm formation were noted to increase in the presence of the nanoparticles, and expression of the key genes involved in biofilm formation was studied by RT-PCR. - Highlights: • Toxicity of NPs towards freshwater sediment bacteria at sub-ppm concentrations. • Decreased toxicity of the nanoparticles in the consortium of microorganisms. • Enhanced bacterial resistance through EPS and biofilm formation in the presence of NPs. • Considerable surface damage of cells and internalization of NPs. • Gene expression analyses related to biofilm formation in the presence of NPs.« less

Intranasal agomelatine solid lipid nanoparticles to enhance brain delivery: formulation, optimization and in vivo pharmacokinetics

PubMed Central

Fatouh, Ahmed M; Elshafeey, Ahmed H; Abdelbary, Ahmed

2017-01-01

Purpose Agomelatine is a novel antidepressant drug suffering from an extensive first-pass metabolism leading to a diminished absolute bioavailability. The aim of the study is: first to enhance its absolute bioavailability, and second to increase its brain delivery. Methods To achieve these aims, the nasal route was adopted to exploit first its avoidance of the hepatic first-pass metabolism to increase the absolute bioavailability, and second the direct nose-to-brain pathway to enhance the brain drug delivery. Solid lipid nanoparticles were selected as a drug delivery system to enhance agomelatine permeability across the blood–brain barrier and therefore its brain delivery. Results The optimum solid lipid nanoparticles have a particle size of 167.70 nm ±0.42, zeta potential of −17.90 mV ±2.70, polydispersity index of 0.12±0.10, entrapment efficiency % of 91.25%±1.70%, the percentage released after 1 h of 35.40%±1.13% and the percentage released after 8 h of 80.87%±5.16%. The pharmacokinetic study of the optimized solid lipid nanoparticles revealed a significant increase in each of the plasma peak concentration, the AUC(0–360 min) and the absolute bioavailability compared to that of the oral suspension of Valdoxan® with the values of 759.00 ng/mL, 7,805.69 ng⋅min/mL and 44.44%, respectively. The optimized solid lipid nanoparticles gave a drug-targeting efficiency of 190.02, which revealed more successful brain targeting by the intranasal route compared with the intravenous route. The optimized solid lipid nanoparticles had a direct transport percentage of 47.37, which indicates a significant contribution of the direct nose-to-brain pathway in the brain drug delivery. Conclusion The intranasal administration of agomelatine solid lipid nanoparticles has effectively enhanced both the absolute bioavailability and the brain delivery of agomelatine. PMID:28684900

The impact of nanoparticles on aerobic degradation of municipal solid waste.

PubMed

Yazici Guvenc, Senem; Alan, Burcu; Adar, Elanur; Bilgili, Mehmet Sinan

2017-04-01

The amount of nanoparticles released from industrial and consumer products has increased rapidly in the last decade. These products may enter landfills directly or indirectly after the end of their useful life. In order to determine the impact of TiO 2 and Ag nanoparticles on aerobic landfilling processes, municipal solid waste was loaded to three pilot-scale aerobic landfill bioreactors (80 cm diameter and 350 cm height) and exposed to TiO 2 (AT) and Ag (AA) nanoparticles at total concentrations of 100 mg kg -1 of solid waste. Aerobic landfill bioreactors were operated under the conditions about 0.03 L min -1 kg -1 aeration rate for 250 days, during which the leachate, solid waste, and gas characteristics were measured. The results indicate that there was no significant difference in the leachate characteristics, gas constituents, solid quality parameters, and temperature variations, which are the most important indicators of landfill operations, and overall aerobic degradation performance between the reactors containing TiO 2 and Ag nanoparticles, and control (AC) reactor. The data also indicate that the pH levels, ionic strength, and the complex formation capacity of nanoparticles with Cl - ions can reduce the toxicity effects of nanoparticles on aerobic degradation processes. The results suggest that TiO 2 and Ag nanoparticles at concentrations of 100 mg kg -1 of solid waste do not have significant impacts on aerobic biological processes and waste management systems.

Differential effects of P25 TiO2 nanoparticles on freshwater green microalgae: Chlorella and Scenedesmus species.

PubMed

Roy, Rajdeep; Parashar, Abhinav; Bhuvaneshwari, M; Chandrasekaran, N; Mukherjee, Amitava

2016-07-01

P25 TiO2 nanoparticles majorly used in cosmetic products have well known detrimental effects towards the aquatic environment. In a freshwater ecosystem, Chlorella and Scenedesmus are among the most commonly found algal species frequently used to study the effects of metal oxide nanoparticles. A comparative study has been conducted herein to investigate differences in the toxic effects caused by these nanoparticles towards the two algae species. The three different concentrations of P25 TiO2 NPs (0.01, 0.1 & 1μg/mL, i.e., 0.12, 1.25 and 12.52μM) were selected to correlate surface water concentrations of the nanoparticles, and filtered and sterilized fresh water medium was used throughout this study. There was significant increase (p<0.001) in hydrodynamic diameter of nanoparticles with respect to both, time (0, 24, 48 and 72h) as well as concentration under all the exposure conditions. Although, significant dose-dependent morphological (surface area & biovolume) interspecies variations were not observed, it was evident at the highest concentration of exposure within individuals. At 1μg/mL exposure concentration, a significant difference in toxicity was noted between Chlorella and Scenedesmus under only visible light (p<0.001) and UVA (p<0.01) irradiation conditions. The viability data were well supported by the results obtained for oxidative stress induced by NPs on the cells. At the highest exposure concentration, superoxide dismutase and reduced glutathione activities were assessed for both the algae under all the irradiation conditions. Increased catalase activity and LPO release complemented the cytotoxic effects observed. Significant interspecies variations were noted for these parameters under UVA and visible light exposed cells of Chlorella and Scenedesmus species, which could easily be correlated with the uptake of the NPs. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of Ag nanoparticle concentration on the electrical and ferroelectric properties of Ag/P(VDF-TrFE) composite films

DOE PAGES

Paik, Haemin; Choi, Yoon -Young; Hong, Seungbum; ...

2015-09-04

Here, we investigated the effect of the Ag nanoparticles on the ferroelectric and piezoelectric properties of Ag/poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) composite films. We found that the remanent polarization and direct piezoelectric coefficient increased up to 12.14 μC/cm 2 and 20.23 pC/N when the Ag concentration increased up to 0.005 volume percent (v%) and decreased down to 9.38 μC/cm 2 and 13.45 pC/N when it increased up to 0.01 v%. Further increase in Ag concentration resulted in precipitation of Ag phase and significant leakage current that hindered any meaningful measurement of the ferroelectric and piezoelectric properties. 46% increase of the remanent polarization valuemore » and 27% increase of the direct piezoelectric coefficient were observed in the film with the 0.005 v% of the Ag nanoparticles added without significant changes to the crystalline structure confirmed by both X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) experiments. The enhancements of both the ferroelectric and piezoelectric properties are attributed to the increase in the effective electric field induced by the reduction in the effective volume of P(VDF-TrFE) that results in more aligned dipoles.« less

Enhanced Radiofrequency Ablation With Magnetically Directed Metallic Nanoparticles.

PubMed

Nguyen, Duy T; Tzou, Wendy S; Zheng, Lijun; Barham, Waseem; Schuller, Joseph L; Shillinglaw, Benjamin; Quaife, Robert A; Sauer, William H

2016-05-01

Remote heating of metal located near a radiofrequency ablation source has been previously demonstrated. Therefore, ablation of cardiac tissue treated with metallic nanoparticles may improve local radiofrequency heating and lead to larger ablation lesions. We sought to evaluate the effect of magnetic nanoparticles on tissue sensitivity to radiofrequency energy. Ablation was performed using an ablation catheter positioned with 10 g of force over prepared ex vivo specimens. Tissue temperatures were measured and lesion volumes were acquired. An in vivo porcine thigh model was used to study systemically delivered magnetically guided iron oxide (FeO) nanoparticles during radiofrequency application. Magnetic resonance imaging and histological staining of ablated tissue were subsequently performed as a part of ablation lesion analysis. Ablation of ex vivo myocardial tissue treated with metallic nanoparticles resulted in significantly larger lesions with greater impedance changes and evidence of increased thermal conductivity within the tissue. Magnet-guided localization of FeO nanoparticles within porcine thigh preps was demonstrated by magnetic resonance imaging and iron staining. Irrigated ablation in the regions with greater FeO, after FeO infusion and magnetic guidance, created larger lesions without a greater incidence of steam pops. Metal nanoparticle infiltration resulted in significantly larger ablation lesions with altered electric and thermal conductivity. In vivo magnetic guidance of FeO nanoparticles allowed for facilitated radiofrequency ablation without direct infiltration into the targeted tissue. Further research is needed to assess the clinical applicability of this ablation strategy using metallic nanoparticles for the treatment of cardiac arrhythmias. © 2016 American Heart Association, Inc.

Blood clot detection using magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Khurshid, Hafsa; Friedman, Bruce; Berwin, Brent; Shi, Yipeng; Ness, Dylan B.; Weaver, John B.

2017-05-01

Deep vein thrombosis, the development of blood clots in the peripheral veins, is a very serious, life threatening condition that is prevalent in the elderly. To deliver proper treatment that enhances the survival rate, it is very important to detect thrombi early and at the point of care. We explored the ability of magnetic particle spectroscopy (MSB) to detect thrombus via specific binding of aptamer functionalized magnetic nanoparticles with the blood clot. MSB uses the harmonics produced by nanoparticles in an alternating magnetic field to measure the rotational freedom and, therefore, the bound state of the nanoparticles. The nanoparticles' relaxation time for Brownian rotation increases when bound [A.M. Rauwerdink and J. B. Weaver, Appl. Phys. Lett. 96, 1 (2010)]. The relaxation time can therefore be used to characterize the nanoparticle binding to thrombin in the blood clot. For longer relaxation times, the approach to saturation is more gradual reducing the higher harmonics and the harmonic ratio. The harmonic ratios of nanoparticles conjugated with anti-thrombin aptamers (ATP) decrease significantly over time with blood clot present in the sample medium, compared with nanoparticles without ATP. Moreover, the blood clot removed from the sample medium produced a significant MSB signal, indicating the nanoparticles are immobilized on the clot. Our results show that MSB could be a very useful non-invasive, quick tool to detect blood clots at the point of care so proper treatment can be used to reduce the risks inherent in deep vein thrombosis.

Evaluation of the Cytotoxic Effects of Hyperthermia and 5-Fluorouracil Loaded Magnetic Nanoparticles on Human Colon Cancer Cell Line HT-29.

PubMed

Eynali, Samira; Khoei, Samideh; Khoei, Sepideh; Esmaelbeygi, Elaheh

2016-10-04

The purpose of this study was to evaluate the combined effects of heat and poly lactic-co-glycolic acid (PLGA) nanoparticles, as 5-fluorouracil carriers with/without iron oxide core, on the viability and proliferation capacity of human colon cancer cell line HT-29 in the spheroid model. HT-29 spheroid cells were treated with different concentrations of 5-FU or 5-FU loaded into both nanoparticles for 74 h. Hyperthermia was then performed at 43°C for 60 min. Finally, the effects of the mentioned treatments on cell viability and proliferation capacity were evaluated using the trypan blue dye exclusion test and colony formation assay, respectively. Our results showed that hyperthermia, in combination with 5-FU or PLGA nanoparticles as 5-FU carriers, significantly enhanced the cytotoxic effects as compared to the control group. Considering that nanoparticles could increase the intracellular concentration of drugs in cancer cells, the extent of cytotoxic effects following treatment with 5-FU loaded into both nanoparticles was significantly higher than that with free 5-FU. In addition, the presence of iron oxide cores in nanoparticles during hyperthermia enhanced the cytotoxic effects of hyperthermia compared with nanoparticles without iron oxide core. Based on this study, hyperthermia in combination with 5-FU-loaded PLGA nanoparticles with iron oxide core drastically reduced the proliferation capacity of HT-29 cells; therefore, it may be considered a new direction in the treatment of colon cancer.

Zein nanoparticle as a novel BMP6 derived peptide carrier for enhanced osteogenic differentiation of C2C12 cells.

PubMed

Hadavi, Mahvash; Hasannia, Sadegh; Faghihi, Shahab; Mashayekhi, Farhad; Homazadeh, Homayoun; Mostofi, Seyed Behrooz

2018-01-26

Zein nanoparticles as a carrier system for BMP6-derived peptide were prepared by liquid-liquid phase separation procedure and characterized with SEM, DLS, FTIR and thermogravimetric methods. After peptide encapsulation, nanoparticle size increased from 236.3 ± 92.2 nm to 379.4 ± 116.8 nm. The encapsulation efficiency of peptide was 72.6% and the release of peptide from Zein nanoparticles was partly sustained in trypsin containing phosphate buffered saline (pH 7.4) for up to 14 days. Peptide-loaded nanoparticles showed similar cell viability compared with blank ones. ALP activity of C2C12 cells treated with peptide-loaded nanoparticles (500 µg/mL) was evaluated 7, 14, 21 and 28 days after culture. In peptide-loaded nanoparticles, ALP activity was significantly higher (p < .05) compared with other groups at day 14. Alizarin Red S staining showed, C2C12 cells behind peptide-loaded nanoparticles had significantly (p < .05) higher calcium deposition at day 21. The results of RT-qPCR show that the BMP-6 peptide activated expression of RUNX2 as a transcription factor. In turn, RUNX2 regulates SPP1 and BGLAP gene expression, as osteogenic marker genes. The results confirm that the peptide-loaded Zein nanoparticles, as osteoinductive material, may be used to repair small area of bone defects, with low load bearing.

Enhancement of antibacterial properties of silver nanoparticles-ceftriaxone conjugate through Mukia maderaspatana leaf extract mediated synthesis.

PubMed

Harshiny, Muthukumar; Matheswaran, Manickam; Arthanareeswaran, Gangasalam; Kumaran, Shanmugam; Rajasree, Shanmuganathan

2015-11-01

Green synthesis of nanoparticles with low range of toxicity and conjugation to antibiotics has become an attractive area of research for several biomedical applications. Nanoconjugates exhibited notable increase in biological activity compared to free antibiotic molecules. With this perception, we report the biosynthesis of silver nanoparticles using aqueous extract of leaves of Mukia maderaspatana and subsequent conjugation of the silver nanoparticles to antibiotic ceftriaxone. The leaves of this plant are known to be a rich source of phenolic compounds with high antioxidant activity that are used as reducing agents. The size, morphology, crystallinity, composition of the synthesized silver nanoparticles and conjugation of ceftriaxone to silver nanoparticles were studied using analytical techniques. The activity of the conjugates against Bacillus subtilis (MTCC 1790), Klebsiella pneumoniae (MTCC 3384), Staphylococcus aureus (ATCC 25923), and Salmonella typhi (MTCC 3224) was compared to ceftriaxone and unconjugated nanoparticles using disc diffusion method. The effect of silver nanoparticles on the reduction of biofilms of Pseudomonas fluorescens (MTCC 6732) was determined by micro plate assay method. The antioxidant activities of extract, silver nitrate, silver nanoparticles, ceftriaxone and conjugates of nanoparticles were evaluated by radical scavenging 1, 1- diphenyl-2-picrylhydrazyl test. Ultraviolet visible spectroscopy and Fourier transform infrared spectroscopy confirmed the formation of metallic silver nanoparticles and conjugation to ceftriaxone. Atomic force microscopy, transmission electron microscopy and particle size analysis showed that the formed particles were of spherical morphology with appreciable nanosize and the conjugation was confirmed by slight increase in surface roughness. The results thus showed that the conjugation of ceftriaxone with silver nanoparticles has better antioxidant and antimicrobial effects than ceftriaxone and unconjugated nanoparticles. It can be suggested that M. maderaspatana mediated nanoparticle-ceftriaxone conjugate can be used effectively in the production of potential antioxidant and antimicrobial agents. The present study offers a significant overview to the development of novel antimicrobial nanoparticles. Copyright © 2015 Elsevier Inc. All rights reserved.

The effects of gold nanoparticles in wound healing with antioxidant epigallocatechin gallate and α-lipoic acid.

PubMed

Leu, Jyh-Gang; Chen, Siang-An; Chen, Han-Min; Wu, Wen-Mein; Hung, Chi-Feng; Yao, Yeong-Der; Tu, Chi-Shun; Liang, Yao-Jen

2012-07-01

Topical applications of antioxidant agents in cutaneous wounds have attracted much attention. Gold nanoparticles (AuNPs), epigallocatechin gallate (EGCG), and α-lipoic acid (ALA) were shown to have antioxidative effects and could be helpful in wound healing. Their effects in Hs68 and HaCaT cell proliferation and in mouse cutaneous wound healing were studied. Both the mixture of EGCG + ALA (EA) and AuNPs + EGCG + ALA (AuEA) significantly increased Hs68 and HaCaT proliferation and migration. Topical AuEA application accelerated wound healing on mouse skin. Immunoblotting of wound tissue showed significant increase of vascular endothelial cell growth factor and angiopoietin-1 protein expression, but no change of angiopoietin-2 or CD31 after 7 days. After AuEA treatment, CD68 protein expression decreased and Cu/Zn superoxide dismutase increased significantly in the wound area. In conclusion, AuEA significantly accelerated mouse cutaneous wound healing through anti-inflammatory and antioxidation effects. This study may support future studies using other antioxidant agents in the treatment of cutaneous wounds. In this study, topically applied gold nanoparticles with epigallocatechin gallate and alpha-lipoic acid were studied regarding their effects in wound healing in cell cultures. Significant acceleration was demonstrated in wound healing in a murine model. Copyright © 2012 Elsevier Inc. All rights reserved.

Fabrication of hydrophobic fluorinated silica-polyamide thin film nanocomposite reverse osmosis membranes with dramatically improved salt rejection.

PubMed

Pang, Ruizhi; Zhang, Kaisong

2018-01-15

Thin film nanocomposite reverse osmosis (TFN RO) membranes incorporated with hydrophilic nanoparticles show a potential problem that the salt rejection can not be improved significantly. In this study, novel TFN RO membranes incorporated with hydrophobic fluorinated silica nanoparticles were fabricated to improve the salt rejection. Fluorinated silica nanoparticles were well dispersed in organic phase during the interfacial polymerization (IP) process. The TFN RO membranes were characterized with attenuated total reflectance infra-red, field emission scanning electron microscopy, atomic force microscopy and water contact angle measurements. The preparation conditions of TFN RO membranes, including IP reaction time, organic solvent removal time, and fluorinated silica loading, were optimized by characterizing desalination performance using 2000ppm NaCl aqueous solution at 1.55MPa and 25°C. The salt rejection increased significantly from 96.0% without fluorinated silica nanoparticles to 98.6% with the optimal 0.12% (w/v) fluorinated silica nanoparticles, while the water flux decreased slightly from 0.99m 3 /m 2 /day to 0.93m 3 /m 2 /day. This study demonstrated the potential use of hydrophobic nanoparticles in high-performance TFN RO membranes. Copyright © 2017 Elsevier Inc. All rights reserved.

Preparation, characterization, and in vitro and in vivo investigation of chitosan-coated poly (d,l-lactide-co-glycolide) nanoparticles for intestinal delivery of exendin-4

PubMed Central

Wang, Mengshu; Zhang, Yong; Feng, Jiao; Gu, Tiejun; Dong, Qingguang; Yang, Xu; Sun, Yanan; Wu, Yongge; Chen, Yan; Kong, Wei

2013-01-01

Background Exendin-4 is an incretin mimetic agent approved for type 2 diabetes treatment. However, the required frequent injections restrict its clinical application. Here, the potential use of chitosan-coated poly (d,l-lactide-co-glycolide) (CS-PLGA) nanoparticles was investigated for intestinal delivery of exendin-4. Methods and results Nanoparticles were prepared using a modified water–oil–water (w/o/w) emulsion solvent-evaporation method, followed by coating with chitosan. The physical properties, particle size, and cell toxicity of the nanoparticles were examined. The cellular uptake mechanism and transmembrane permeability were performed in Madin-Darby canine kidney-cell monolayers. Furthermore, in vivo intraduodenal administration of exendin-4-loaded nanoparticles was carried out in rats. The PLGA nanoparticle coating with chitosan led to a significant change in zeta potential, from negative to positive, accompanied by an increase in particle size of ~30 nm. Increases in both the molecular weight and degree of deacetylation of chitosan resulted in an observable increase in zeta potential but no apparent change in the particle size of ~300 nm. Both unmodified PLGA and chitosan-coated nanoparticles showed only slight cytotoxicity. Use of different temperatures and energy depletion suggested that the cellular uptake of both types of nanoparticles was energy-dependent. Further investigation revealed that the uptake of PLGA nanoparticles occurred via caveolin-mediated endocytosis and that of CS-PLGA nanoparticles involved both macropinocytosis and clathrin-mediated endocytosis, as evidenced by using endocytic inhibitors. However, under all conditions, CS-PLGA nanoparticles showed a greater potential to be transported into cells, as shown by flow cytometry and confocal microscopy. Transmembrane permeability analysis showed that unmodified and modified PLGA nanoparticles could improve the transport of exendin-4 by up to 8.9- and 16.5-fold, respectively, consistent with the evaluation in rats. Conclusion The chitosan-coated nanoparticles have a higher transport potential over both free drug and unmodified particles, providing support for their potential development as a candidate oral delivery agent for exendin-4. PMID:23658482

Design and construction of multifunctional hyperbranched polymers coated magnetite nanoparticles for both targeting magnetic resonance imaging and cancer therapy.

PubMed

Mashhadi Malekzadeh, Asemeh; Ramazani, Ali; Tabatabaei Rezaei, Seyed Jamal; Niknejad, Hassan

2017-03-15

Magnetic drug targeting is a drug delivery strategy that can be used to improve the therapeutic efficiency on tumor cells and reduce the side effects on normal cells and tissues. The aim in this study is designing a novel multifunctional drug delivery system based on superparamagnetic nanoparticles for cancer therapy. Magnetic nanoparticles were synthesized by coprecipitation of iron oxide followed by coating with poly citric acid (PCA) dendritic macromolecules via bulk polymerization strategy. It was further surface-functionalized with poly(ethylene glycol) (PEG) and then to achieve tumor cell targeting property, folic acid was further incorporated to the surface of prepared carriers via a facile coupling reaction between the hydroxyl end group of the PEG and the carboxyl group of folic acid. The so prepared nanocarriers (Fe 3 O 4 @PCA-PEG-FA) were characterized by X-ray diffraction, TEM, TGA, FT-IR, DLS and VSM techniques. The room temperature VSM measurements showed that magnetic particles were superparamagnetic. Transmission electron microscopy and dynamic light scattering were also performed which revealed that size of nanocarriers was lying in the range of 10-49nm. Quercetin loading and release profiles of prepared nanocarriers showed that up to 83% of loaded drug was released in 250h. Fluorescent microscopy showed that the cellular uptake by folate receptor-overexpressing HeLa cells of the quercetin-loaded Fe 3 O 4 @PCA-PEG-FA nanoparticles was higher than that of non-folate conjugated nanoparticles. Thus, folate conjugation significantly increased nanoparticle cytotoxicity. Also, T 2 -weighted MRI images of Fe 3 O 4 @PCA-PEG-FA nanoparticles showed that the magnetic resonance signal is enhanced significantly with increasing nanoparticle concentration in water and they also served as MRI contrast agents with relaxivities of 3.4mM -1 s -1 (r 1 ) and 99.8mM -1 s -1 (r 2 ). The results indicate that this multifunctional nanocarrier is a significant breakthrough in developing a drug delivery vehicle that combines drug targeting as well as sensing and therapy at the same time. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect of metal (hydr)oxide nano-enabling on intraparticle mass transport of organic contaminants in hybrid granular activated carbon.

PubMed

Garcia, Jose; Markovski, Jasmina; McKay Gifford, J; Apul, Onur; Hristovski, Kiril D

2017-05-15

The overarching goal of this study was to ascertain the changes in intraparticle mass transport rates for organic contaminants resulting from nano-enabled hybridization of commercially available granular activated carbon (GAC). Three different nano-enabled hybrid media were fabricated by in-situ synthesizing titanium dioxide nanoparticles inside the pores of GAC sorbent, characterized, and evaluated for removal of two model organic contaminants under realistic conditions to obtain the intraparticle mass transport (pore and surface diffusion) coefficients. The results validated the two hypotheses that: (H1) the pore diffusion rates of organic contaminants linearly decrease with decrease in cumulative pore volume caused by increase in metal (hydr)oxide nanoparticle content inside the pores of the hybrid GAC sorbent; and (H2) introduction of metal (hydr)oxide nanoparticles initially increases surface diffusivity, but additional loading causes its decrease as the increase in metal (hydr)oxide nanoparticles content continues to reduce the porosity of the GAC sorbent. Nano-enabled hybridization of commercially available GAC with metal (hydr)oxides has the potential to significantly increase the intraparticle mass transport limitations for organic contaminants. Introduction of metal (hydr)oxide nanoparticles inside the pores of a pristine sorbent causes the pore diffusion rates of organic contaminants to decrease as the cumulative pore volume is reduced. In contrast, the introduction of limited amounts of metal (hydr)oxide nanoparticles appears to facilitate the surface diffusion rates of these contaminants. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of aerosil dispersion on the activated kinetics of the LC1-xSilx system.

PubMed

Sharma, Dipti; MacDonald, John C; Iannacchione, Germano S

2006-12-28

This study explores the role of aerosil dispersion on activated phase transitions of bulk octylcyanobiphenyl (8CB) liquid crystals by performing heating rate-dependent experiments. Differential scanning calorimetry (DSC) was used at various heating ramp rates in order to probe the activated phase dynamics of the system. The system, LC1-xSilx, was prepared by mixing aerosil nanoparticles (7 nm in diameter) in the bulk 8CB by the solvent dispersion method (SDM). LC represents bulk 8CB, and Sil represents aerosil nanoparticles with concentration x in percent. The concentration of the aerosil nanoparticles (x) varied from 0 to 0.2 g/cm3 in the bulk 8CB. Well-defined, endothermic peaks were found on a heating scan at melting and at the smectic-A to nematic (SmA-N) and nematic to isotropic (N-I) transitions. These peaks show a temperature shift and a change in their shapes and sizes in the presence of aerosil nanoparticles. In addition, an exothermic peak also appeared before the melting peak during the heating scan in the presence of aerosil nanoparticles. All transitions shifted significantly with different heating ramp rates, following an Arrhenius behavior, showing activated kinetics. The presence of aerosil nanoparticles caused a significant increase in the enthalpy and a decrease in the activation energy compared to the results found in bulk 8CB. This behavior can be explained by aerosil dispersion in the LC1-xSilx, inducing a disorder in the bulk 8CB. Infrared (IR) spectroscopy shows a shift to higher frequency for the broad peak at 1082 cm-1, corresponding to an Si-O bond as the density of the aerosil increases, and can be explained in terms of surface and molecular interactions between aerosil nanoparticles and 8CB liquid crystal molecules.

Metabolism, survival, and gene expression of Pseudomonas putida to hematite nanoparticles mediated by surface-bound humic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouyang, Kai; Walker, Sharon L.; Yu, Xiao-Ying

Natural organic matter (NOM) is likely to coat naturally occurring nanoparticles (NNPs) in the soil environment and poses distinct effects on the interaction between NPs and soil microorganisms, however such topic has not been well investigated. This study explored the influence of nanoparticle surface-bound humic acid (HA, as a model NOM) on the toxicity of hematite NPs (i.e., nano-Fe2O3) to Pseudomonas putida (P. putida). Results showed that nano-Fe2O3 could inhibit the bacterial growth with an IC50 of 23.58 mg L-1, while nanoparticle surface-bound HA could significantly alleviate the P. putida toxicity of nano-Fe2O3. IC50 of nano-Fe2O3 increased to 4774.23 mgmore » L-1 as a result of surface-saturation by HA. Co-precipitation experiment and transmission electron microscopy observation revealed that nanoparticle surface-bound HA prevented the adhesion of nano-Fe2O3 to the cells as well as limited cell internalization of nanoparticles due to the increased electrostatic repulsion. The generation of intracellular reactive oxygen species (ROS) was significantly limited by the nanoparticle surface-bound HA. The prevention of adhesion and inhibition of ROS generation could account for the HA-mitigated nanotoxicity. Interfacial interactions between hematite NPs and cell membrane were also evaluated on the basis of the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, and the magnitude of interaction energy barrier correlated well with the 48 h LC50 data of hematite NPs to P. putida. This result implies that metal oxide NPs with strong association with the cell surface might induce more severe cytotoxicity in microorganisms.« less

In vitro toxicity of nanoparticles in BRL 3A rat liver cells.

PubMed

Hussain, S M; Hess, K L; Gearhart, J M; Geiss, K T; Schlager, J J

2005-10-01

This study was undertaken to address the current deficient knowledge of cellular response to nanosized particle exposure. The study evaluated the acute toxic effects of metal/metal oxide nanoparticles proposed for future use in industrial production methods using the in vitro rat liver derived cell line (BRL 3A). Different sizes of nanoparticles such as silver (Ag; 15, 100 nm), molybdenum (MoO(3); 30, 150 nm), aluminum (Al; 30, 103 nm), iron oxide (Fe(3)O(4); 30, 47 nm), and titanium dioxide (TiO(2); 40 nm) were evaluated for their potential toxicity. We also assessed the toxicity of relatively larger particles of cadmium oxide (CdO; 1 microm), manganese oxide (MnO(2); 1-2 microm), and tungsten (W; 27 microm), to compare the cellular toxic responses with respect to the different sizes of nanoparticles with different core chemical compositions. For toxicity evaluations, cellular morphology, mitochondrial function (MTT assay), membrane leakage of lactate dehydrogenase (LDH assay), reduced glutathione (GSH) levels, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were assessed under control and exposed conditions (24h of exposure). Results showed that mitochondrial function decreased significantly in cells exposed to Ag nanoparticles at 5-50 microg/ml. However, Fe(3)O(4), Al, MoO(3) and TiO(2) had no measurable effect at lower doses (10-50 microg/ml), while there was a significant effect at higher levels (100-250 microg/ml). LDH leakage significantly increased in cells exposed to Ag nanoparticles (10-50 microg/ml), while the other nanoparticles tested displayed LDH leakage only at higher doses (100-250 microg/ml). In summary the Ag was highly toxic whereas, MoO(3) moderately toxic and Fe(3)O(4), Al, MnO(2) and W displayed less or no toxicity at the doses tested. The microscopic studies demonstrated that nanoparticle-exposed cells at higher doses became abnormal in size, displaying cellular shrinkage, and an acquisition of an irregular shape. Due to toxicity of silver, further study conducted with reference to its oxidative stress. The results exhibited significant depletion of GSH level, reduced mitochondrial membrane potential and increase in ROS levels, which suggested that cytotoxicity of Ag (15, 100 nm) in liver cells is likely to be mediated through oxidative stress.

Characterization and toxicology evaluation of chitosan nanoparticles on the embryonic development of zebrafish, Danio rerio.

PubMed

Wang, Yanbo; Zhou, Jinru; Liu, Lin; Huang, Changjiang; Zhou, Deqing; Fu, Linglin

2016-05-05

In the present study, chitosan nanoparticles were prepared, characterized and used to evaluate the embryonic toxicology on zebrafish (Danio rerio). The average particle size of chitosan nanoparticles was 84.86nm. The increased mortality and decreased hatching rate was found in the zebrafish embryo exposure to normal chitosan particles and chitosan nanoparticles with the increased addition concentration. At 120h post-fertilization (hpf), the rate of mortality were 25.0 and 44.4% in the groups treated with chitosan nanoparticles and normal chitosan particles at 250mg/L, respectively. At 72hpf, the hatching rate in the groups treated with normal chitosan particles were lower (P<0.01) at 300 and 400mg/L than those of the corresponding control groups, respectively. However, there were no significant differences between the groups treated with chitosan nanoparticles and the control groups across all the addition concentrations. More abundant typical malformation of embryos was observed in the groups treated with normal chitosan particles compared with those treated with chitosan nanoparticles. The LC50 (medium lethal concentration) of chitosan nanoparticles was 280mg/L at 96hpf and 270mg/L at 120hpf. As for normal chitosan particles, the LC50 was 257mg/L at both 96hpf and 120hpf. The TC50 (medium teratogenic concentration) of the zebrafish treated with chitosan nanoparticles and normal chitosan particles were 257mg/L and 137mg/L, respectively. It indicated that the chitosan nanoparticles were relatively more secure compared with normal chitosan particles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of drying conditions on crystallinity of amylose nanoparticles prepared by nanoprecipitation.

PubMed

Yan, Xiaoxia; Chang, Yanjiao; Wang, Qian; Fu, Youjia; Zhou, Jiang

2017-04-01

In this study, amylose nanoparticles prepared by nanoprecipitation were dried at different conditions. The crystalline structure, crystallinity, re-dispersibility and morphological characteristic of the amylose nanoparticles after drying were investigated. X-ray diffraction analysis revealed that the V-type crystalline structure of the amylose nanoparticles formed in the drying process instead of the precipitation process, and drying condition significantly affects the crystallinity. The temperature cycles drying at 4°C and 40°C considerably increased crystallinity of the amylose nanoparticles, 24h (4/40°C, 12h/12h) drying under 11% relative humidity could give rise to a crystallinity up to 50.05%. The applied drying procedures had no obvious effect on the appearance of the amylose nanoparticles. The Z average-size (d. nm) and polydispersity index (PDI) obtained from dynamic light scattering analysis suggested that the drying processes caused some aggregates, but the dried amylose nanoparticles could be well dispersed in water. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and evaluation of quercetin-loaded lecithin-chitosan nanoparticles for topical delivery.

PubMed

Tan, Qi; Liu, Weidong; Guo, Chenyu; Zhai, Guangxi

2011-01-01

The purpose of this study was to investigate lecithin-chitosan nanoparticles as a topical delivery system for quercetin. Tocopheryl propylene glycol succinate was chosen to be the surfactant for the nanosystem. The mean particle size of the nanoparticles was 95.3 nm, and the entrapment efficiency and drug loading for quercetin were 48.5% and 2.45%, respectively. Topical delivery in vitro and in vivo of the quercetin-loaded nanoparticles was evaluated using quercetin propylene glycol solution as the control. Compared with quercetin solution, the quercetin-loaded nanoparticles showed higher permeation ability, and significantly increased accumulation of quercetin in the skin, especially in the epidermis. Microstructure observation of the skin surface after administration indicated that the interaction between ingredients of the nanoparticles and the skin surface markedly changed the morphology of the stratum corneum and disrupted the corneocyte layers, thus facilitating the permeation and accumulation of quercetin in skin. Lecithin-chitosan nanoparticles are a promising carrier for topical delivery of quercetin.

Preparation and evaluation of quercetin-loaded lecithin-chitosan nanoparticles for topical delivery

PubMed Central

Tan, Qi; Liu, Weidong; Guo, Chenyu; Zhai, Guangxi

2011-01-01

Background The purpose of this study was to investigate lecithin-chitosan nanoparticles as a topical delivery system for quercetin. Methods Tocopheryl propylene glycol succinate was chosen to be the surfactant for the nanosystem. The mean particle size of the nanoparticles was 95.3 nm, and the entrapment efficiency and drug loading for quercetin were 48.5% and 2.45%, respectively. Topical delivery in vitro and in vivo of the quercetin-loaded nanoparticles was evaluated using quercetin propylene glycol solution as the control. Results Compared with quercetin solution, the quercetin-loaded nanoparticles showed higher permeation ability, and significantly increased accumulation of quercetin in the skin, especially in the epidermis. Microstructure observation of the skin surface after administration indicated that the interaction between ingredients of the nanoparticles and the skin surface markedly changed the morphology of the stratum corneum and disrupted the corneocyte layers, thus facilitating the permeation and accumulation of quercetin in skin. Conclusion Lecithin-chitosan nanoparticles are a promising carrier for topical delivery of quercetin. PMID:21904452

Biochemical analysis of Cassia fistula aqueous extract and phytochemically synthesized gold nanoparticles as hypoglycemic treatment for diabetes mellitus

PubMed Central

Daisy, P; Saipriya, K

2012-01-01

Cassia fistula stem bark was used for the preparation of aqueous extract and synthesis of gold nanoparticles to evaluate the hypoglycemic effects of the plant. The synthesized gold nanoparticles were characterized by ultraviolet-visible spectroscopy for their absorbance pattern, Fourier transform infrared spectroscopy to identify possible functional groups, and scanning electron microscopy to determine the size of the nanoparticles. The present investigation reports the efficacy of the gold nanoparticles as promising in the treatment of hyperglycemia. Body weight, serum glucose concentrations, liver function tests, kidney function tests, and lipid profile were analyzed. A significantly larger decrease in serum biochemistry parameters and an increase in body weight, total protein levels, and high-density lipoprotein were observed in rats with streptozotocin-induced diabetes treated with gold nanoparticles than in the ones treated with the aqueous extract. The results of this study confirm that C. fistula gold nanoparticles have promising antidiabetic properties. PMID:22419867

[Effect of stability and dissolution of realgar nano-particles using solid dispersion technology].

PubMed

Guo, Teng; Shi, Feng; Yang, Gang; Feng, Nian-Ping

2013-09-01

To improve the stability and dissolution of realgar nano-particles by solid dispersion. Using polyethylene glycol 6000 and poloxamer-188 as carriers, the solid dispersions were prepare by melting method. XRD, microscopic inspection were used to determine the status of realgar nano-particles in solid dispersions. The content and stability test of As(2)0(3) were determined by DDC-Ag method. Hydride generation atomic absorption spectrometry was used to determine the content of Arsenic and investigated the in vitro dissolution behavior of solid dispersions. The results of XRD and microscopic inspection showed that realgar nano-particles in solid dispersions were amorphous. The dissolution amount and rate of Arsenic from realgar nano-particles of all solid dispersions were increased significantly, the reunion of realgar nano-particles and content of As(2)0(3) were reduced for the formation of solid dispersions. The solid dispersion of realgar nano-particles with poloxamer-188 as carriers could obviously improve stability, dissolution and solubility.

Controlled functionalization of nanoparticles & practical applications

NASA Astrophysics Data System (ADS)

Rashwan, Khaled

With the increasing use of nanoparticles in both science and industry, their chemical modification became a significant part of nanotechnology. Unfortunately, most commonly used procedures provide just randomly functionalized materials. The long-term objective of our work is site- and stoichiometrically-controlled functionalization of nanoparticles with the utilization of solid supports and other nanostructures. On the examples of silica nanoparticles and titanium dioxide nanorods, we have obtained results on the solid-phase chemistry, method development, and modeling, which advanced us toward this goal. At the same time, we explored several applications of nanoparticles that will benefit from the controlled functionalization: imaging of titanium-dioxide-based photocatalysts, bioimaging by fluorescent nanoparticles, drug delivery, assembling of bone implants, and dental compositions. Titanium dioxide-based catalysts are known for their catalytic activity and their application in solar energy utilization such as photosplitting of water. Functionalization of titanium dioxide is essential for enhancing bone-titanium dioxide nanotube adhesion, and, therefore, for its application as an interface between titanium implants and bones. Controlled functionalization of nanoparticles should enhance sensitivity and selectivity of nanoassemblies for imaging and drug delivery applications. Along those lines, we studied the relationship between morphology and surface chemistry of nanoparticles, and their affinity to organic molecules (salicylic and caffeic acid) using Langmuir adsorption isotherms, and toward material surfaces using SEM- and TEM-imaging. We focused on commercial samples of titanium dioxide, titanium dioxide nanorods with and without oleic acid ligands, and differently functionalized silica nanoparticles. My work included synthesis, functionalization, and characterization of several types of nanoparticles, exploring their application in imaging, dentistry, and bone implant construction. Significant part of my experimental efforts was devoted to the solid-phase method development using model organic molecules, as well as affinity of nanoparticles to the functional groups and surfaces that can be used as linkages for constructing functional nanodevices.

Solar Spectrum Photocatalytic Conversion of CO2 and Water Vapor Into Hydrocarbons Using TiO2 Nanoparticle Membranes

NASA Astrophysics Data System (ADS)

Rani, Sanju; Bao, Ningzhong; Roy, Somnath C.

2014-01-01

A viable option for recycling carbon dioxide is through the sunlight-powered photocatalytic conversion of CO2 and water vapor into hydrocarbon fuels over highly active nanocatalysts. With photocatalytic CO2 reduction sunlight, a renewable energy source as durable as the sun, is used to drive the catalytic reaction with the resultant fuel products compatible with the current hydrocarbon-based energy infrastructure. The use of co-catalyst (Cu, Pt)-sensitized TiO2 nanoparticle wafers in the photocatalytic conversion of CO2 and water vapor to hydrocarbon fuels, with optimal humidity levels and exposure times established. We also attempted to increase product formation by sputtering both co-catalysts on the nanoparticle wafer's surface, with the resulting product rates significantly higher than that of either the Cu or Pt coated samples. When the TiO2 nanoparticle wafers are used in a flow-through membrane implementation we find a significant increase in product rates of formation, including methane, hydrogen, and carbon monoxide. We believe that nanocatalyst-based flow-through membranes are a viable route for achieving large-scale and low cost photocatalytic solar fuel production.

EFFECT OF COPPER OXIDE NANOPARTICLES TO SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS) AT DIFFERENT SALINITIES

PubMed Central

ATES, M.; DUGO, M.A.; DEMIR, V.; ARSLAN, Z.; TCHOUNWOU, P.B.

2014-01-01

Nanotechnologies research has become a significant priority worldwide. Many engineered nano-sized materials have been increasingly used in consumer products. But the adverse effects of these nanoparticles on the environment and organisms have recently drawn much attention. The present study investigated the effects of different concentrations of copper oxide nanoparticles (CuO NPs) on the sheepshead minnow (Cyprinodon variegatus) at different salinity regimes, since it is able to withstand a wide range of salinities. The results indicated that CuO NPs could cause behavioral changes in the fish, such as increased mucus secretion, less general activity and loss of equilibrium. No mortality was observed at the presence of CuO NPs during the experiments. But higher oxidative stress was determined at half strength seawater than seawater exposure medium, which can be associated with the decreasing toxicity of CuO NPs as salinity increases. In addition, Cu contents in the tissues of the fish were significantly higher (p<0.05) in the low salinity. The order of Cu accumulation in the fish's organs was intestine > gills > liver. PMID:25411584

Development of megestrol acetate solid dispersion nanoparticles for enhanced oral delivery by using a supercritical antisolvent process.

PubMed

Ha, Eun-Sol; Kim, Jeong-Soo; Baek, In-Hwan; Yoo, Jin-Wook; Jung, Yunjin; Moon, Hyung Ryong; Kim, Min-Soo

2015-01-01

In the present study, solid dispersion nanoparticles with a hydrophilic polymer and surfactant were developed using the supercritical antisolvent (SAS) process to improve the dissolution and oral absorption of megestrol acetate. The physicochemical properties of the megestrol acetate solid dispersion nanoparticles were characterized using scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, and a particle-size analyzer. The dissolution and oral bioavailability of the nanoparticles were also evaluated in rats. The mean particle size of all solid dispersion nanoparticles that were prepared was <500 nm. Powder X-ray diffraction and differential scanning calorimetry measurements showed that megestrol acetate was present in an amorphous or molecular dispersion state within the solid dispersion nanoparticles. Hydroxypropylmethyl cellulose (HPMC) solid dispersion nanoparticles significantly increased the maximum dissolution when compared with polyvinylpyrrolidone K30 solid dispersion nanoparticles. The extent and rate of dissolution of megestrol acetate increased after the addition of a surfactant into the HPMC solid dispersion nanoparticles. The most effective surfactant was Ryoto sugar ester L1695, followed by D-α-tocopheryl polyethylene glycol 1000 succinate. In this study, the solid dispersion nanoparticles with a drug:HPMC:Ryoto sugar ester L1695 ratio of 1:2:1 showed >95% rapid dissolution within 30 minutes, in addition to good oral bioavailability, with approximately 4.0- and 5.5-fold higher area under the curve (0-24 hours) and maximum concentration, respectively, than raw megestrol acetate powder. These results suggest that the preparation of megestrol acetate solid dispersion nanoparticles using the supercritical antisolvent process is a promising approach to improve the dissolution and absorption properties of megestrol acetate.

Osteoinductive-nanoscaled silk/HA composite scaffolds for bone tissue engineering application.

PubMed

Huang, Xiaowei; Bai, Shumeng; Lu, Qiang; Liu, Xi; Liu, Shanshan; Zhu, Hesun

2015-10-01

Osteoinductive silk/hydroxyapatite (HA) composite scaffolds for bone regeneration were prepared by combining silk with HA/silk core-shell nanoparticles. The HA/silk nanoparticles were directly dispersed in silk solution to form uniform silk/HA blend and then composite scaffolds after a freeze-drying process. The HA/silk nanoparticles uniformly distributed in silk scaffolds at nanometer scale at varying HA content up to 40%, and substantially improved the compressive strength of the scaffolds produced. Rat bone mesenchymal stem cells (rBMSCs) were cultured in these scaffolds and cell proliferation was analyzed by confocal microscopy and DNA assay. Gene expression and biochemical assays were employed to study the influence of increasing HA/silk nanoparticles on in vitro osteogenic differentiation of rBMSCs. Increasing HA/silk nanoparticles inside silk scaffolds improved the growth and osteogenic capability of rBMSCs in the absence of osteogenic growth factors, and also significantly increased the calcium and collagen I deposition. In addition, compared to silk/HA composite scaffolds containing HA aggregates, the scaffolds loaded with HA/silk nanoparticles showed remarkably higher stiffness and better osteogenic property at same HA content, implying a preferable microenvironment for rBMSCs. These results suggest that the osteogenic property as well as mechanical property of silk/HA scaffolds could be further improved through fabricating their structure and topography at nanometer scale, providing more suitable systems for bone regeneration. © 2014 Wiley Periodicals, Inc.

Evaluation of minimum quantity lubrication grinding with nano-particles and recent related patents.

PubMed

Li, Changhe; Wang, Sheng; Zhang, Qiang; Jia, Dongzhou

2013-06-01

In recent years, a large number of patents have been devoted to developing minimum quantity lubrication (MQL) grinding techniques that can significantly improve both environmentally conscious and energy saving and costeffective sustainable grinding fluid alternatives. Among them, one patent is about a supply system for the grinding fluid in nano-particle jet MQL, which produced MQL lubricant by adding solid nano-particles in degradable grinding fluid. The MQL supply device turns the lubricant to the pulse drops with fixed pressure, unchanged pulse frequency and the same drop diameter. The drops will be produced and injected in the grinding zone in the form of jet flow under high pressure gas and air seal. As people become increasingly demanding on our environment, minimum quantity lubrication has been widely used in the grinding and processing. Yet, it presents the defect of insufficient cooling performance, which confines its development. To improve the heat transfer efficiency of MQL, nano-particles of a certain mass fraction can be added in the minimum quantity of lubricant oil, which concomitantly will improve the lubrication effects in the processing. In this study, the grinding experiment corroborated the effect of nano-particles in surface grinding. In addition, compared with other forms of lubrication, the results presented that the grinding force, the friction coefficient and specific grinding energy of MQL grinding have been significantly weakened, while G ratio greatly rose. These are attributed to the friction oil-film with excellent anti-friction and anti-wear performance, which is generated nano-particles at the wheel/workpiece interface. In this research, the cooling performance of nano-particle jet MQL was analyzed. Based on tests and experiments, the surface temperature was assayed from different methods, including flood lubricating oil, dry grinding, MQL grinding and nano-particle jet MQL grinding. Because of the outstanding heat transfer performance of nano-particles, the ratio of heat delivered by grinding media was increased, leading to lower temperature in the grinding zone. Results demonstrate that nano-particle jet MQL has satisfactory cooling performance as well as a promising future of extensive application.

Targeting glioma stem cells enhances anti-tumor effect of boron neutron capture therapy

PubMed Central

Sun, Ting; Li, Yanyan; Huang, Yulun; Zhang, Zizhu; Yang, Weilian; Du, Ziwei; Zhou, Youxin

2016-01-01

The uptake of (10)boron by tumor cells plays an important role for cell damage in boron neutron capture therapy (BNCT). CD133 is frequently expressed in the membrane of glioma stem cells (GSCs), resistant to radiotherapy and chemotherapy, and represents a potential therapeutic target. To increase (10)boron uptake in GSCs, we created a polyamido amine dendrimer, conjugated CD133 monoclonal antibodies, encapsulating mercaptoundecahydrododecaborate (BSH) in void spaces, and monitored the uptake of the bioconjugate nanoparticles by GSCs in vitro and in vivo. Fluorescence microscopy showed the specific uptake of the bioconjugate nanoparticles by CD133-positive GSCs. Treatment with the biconjugate nanoparticles resulted in a significant lethal effect after neutron radiation due to efficient and CD133-independent cellular targeting and uptake in CD133-expressing GSCs. A significantly longer survival occurred in combination with the biconjugate nanoparticles and BSH compared with BSH alone in human intracranial GBM models employing CD133-positive GSCs xenografts. Our data demonstrated that this bioconjugate nanoparticle targets human CD133-positive GSCs and is a potential boron agent in BNCT. PMID:27191269

Targeting glioma stem cells enhances anti-tumor effect of boron neutron capture therapy.

PubMed

Sun, Ting; Li, Yanyan; Huang, Yulun; Zhang, Zizhu; Yang, Weilian; Du, Ziwei; Zhou, Youxin

2016-07-12

The uptake of (10)boron by tumor cells plays an important role for cell damage in boron neutron capture therapy (BNCT). CD133 is frequently expressed in the membrane of glioma stem cells (GSCs), resistant to radiotherapy and chemotherapy, and represents a potential therapeutic target. To increase (10)boron uptake in GSCs, we created a polyamido amine dendrimer, conjugated CD133 monoclonal antibodies, encapsulating mercaptoundecahydrododecaborate (BSH) in void spaces, and monitored the uptake of the bioconjugate nanoparticles by GSCs in vitro and in vivo. Fluorescence microscopy showed the specific uptake of the bioconjugate nanoparticles by CD133-positive GSCs. Treatment with the biconjugate nanoparticles resulted in a significant lethal effect after neutron radiation due to efficient and CD133-independent cellular targeting and uptake in CD133-expressing GSCs. A significantly longer survival occurred in combination with the biconjugate nanoparticles and BSH compared with BSH alone in human intracranial GBM models employing CD133-positive GSCs xenografts. Our data demonstrated that this bioconjugate nanoparticle targets human CD133-positive GSCs and is a potential boron agent in BNCT.

Enhanced performance of P3HT/(PCBM:ZnO:TiO{sub 2}) blend based hybrid organic solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikram, M., E-mail: mianraj.1981@gmail.com; Murray, R.; Imran, M.

Highlights: • We fabricated hybrid bulk heterojunction organic solar cells. • TiO{sub 2} and ZnO nanoparticles replace PCBM with fixed amount of P3HT in active layer • PCE was significantly improved by the introduction of TiO{sub 2} and ZnO. • A possible route toward low-cost OPV. • To the best of my knowledge, this work is the first time going to report. - Abstract: Quaternary blend hybrid organic solar cells enjoy both an increased light absorption range and an easy method to fabricate because of the simple structure. In this study effects of mixing inorganic metal oxides (ZnO and TiO{submore » 2}) nanoparticles to the active layer of organic photovoltaics devices were investigated. The active layer primarily consists of various ratios of electron donor poly (3-hexylthiophene) (P3HT) and an electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) together with nanostructured ZnO and TiO{sub 2} dispersed in chlorobenzene (CB) and 1,2-dichlorobenzene (DCB). The ratio of PCBM to nanoparticles was varied keeping the ratio of P3HT to acceptor material constant. Mixing of nanoparticle plays a significant role in the resulting power conversion efficiency (PCE) of the devices. An increased PCE for ZnO/TiO{sub 2} doped devices can be attributed to increased absorption in the visible region and enhanced charge collection due to the percolation networks formed by metal oxides nanoparticles.« less

Effects of curcumin-loaded PLGA nanoparticles on the RG2 rat glioma model.

PubMed

Orunoğlu, Merdan; Kaffashi, Abbas; Pehlivan, Sibel Bozdağ; Şahin, Selma; Söylemezoğlu, Figen; Oğuz, Kader Karli; Mut, Melike

2017-09-01

Curcumin, the active ingredient of turmeric, has a remarkable antitumor activity against various cancers, including glioblastoma. However, it has poor absorption and low bioavailability; thus, to cross the blood-brain barrier and reach tumor tissue, it needs to be transferred to tumor site by special drug delivery systems, such as nanoparticles. We aimed to evaluate the antitumor activity of curcumin on glioblastoma tissue in the rat glioma-2 (RG2) tumor model when it is loaded on poly(lactic-co-glycolic acid)-1,2-distearoyl-glycerol-3-phospho-ethanolamine-N-[methoxy (polyethylene glycol)-2000] ammonium salt (PLGA-DSPE-PEG) hybrid nanoparticles. Glioblastoma was induced in 42 adult female Wistar rats (250-300g) by RG2 tumor model. The curcumin-loaded nanoparticles were injected by intravenous (n=6) or intratumoral route (n=6). There were five control groups, each containing six rats. First control group was not applied any treatment. The remaining four control groups were given empty nanoparticles or curcumin alone by intravenous or intratumoral route, respectively. The change in tumor volume was assessed by magnetic resonance imaging and histopathology before and 5days after drug injections. Tumor size decreased significantly after 5days of intratumoral injection of curcumin-loaded nanoparticle (from 66.6±44.6 to 34.9±21.7mm 3 , p=0.028), whereas it significantly increased in nontreated control group (from 33.9±21.3 to 123.7±41.1mm 3 , p=0.036) and did not significantly change in other groups (p>0.05 for all). In this in vivo experimental model, intratumoral administration of curcumin-loaded PLGA-DSPE-PEG hybrid nanoparticles was effective against glioblastoma. Curcumine-loaded nanoparticles may have potential application in chemotherapy of glioblastoma. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced Photocatalytic Activity of TiO2 Nanoparticles Supported on Electrically Polarized Hydroxyapatite.

PubMed

Zhang, Xuefei; Yates, Matthew Z

2018-05-23

Fast recombination of photogenerated charge carriers in titanium dioxide (TiO 2 ) remains a challenging issue, limiting the photocatalytic activity. This study demonstrates increased photocatalytic performance of TiO 2 nanoparticles supported on electrically polarized hydroxyapatite (HA) films. Dense and thermally stable yttrium and fluorine co-doped HA films with giant internal polarization were synthesized as photocatalyst supports. TiO 2 nanoparticles deposited on the support were then used to catalyze the photochemical reduction of aqueous silver ions to produce silver nanoparticles. It was found that significantly more silver nanoparticles were produced on polarized HA supports than on depolarized HA supports. In addition, the photodegradation of methyl orange with TiO 2 nanoparticles on polarized HA supports was found to be much faster than with TiO 2 nanoparticles on depolarized HA supports. It is proposed that separation of photogenerated electrons and holes in TiO nanoparticles is promoted by the internal polarization of the HA support, and consequently, the recombination of charge carriers is mitigated. The results imply that materials with large internal polarization can be used in strategies for enhancing quantum efficiency of photocatalysts.

Direct visualization of nanoparticle dynamics at liquid interfaces

NASA Astrophysics Data System (ADS)

Gao, Yige; Kim, Paul; Hoagland, David; Russell, Tom

Ionic liquids, because of their negligible vapor pressures and moderate viscosities, are suitable media to investigate the dynamics of different types of dispersed nanoparticles by scanning electron microscopy. No liquid cell is necessary. Here, Brownian motions of nanoparticles partially wetted at the vacuum-liquid interface are visualized by low voltage SEM under conditions that allow single particle tracking for tens-of-minutes or longer. Conductive, nonconductive, semiconductive, and core-shell conductive-nonconductive nanoparticles have all been studied, and their interactions with each other in one- and two-component layers, as manifested in particle trajectories, differ significantly. For example, Au-coated silica nanoparticles aggregate above a threshold current, whereas aggregated silica-coated Au nanoparticles disaggregate at the same conditions. The impacts of surface concentration of nanoparticle dynamics were observed for one-component and two-component layers, with both global and localized motions visualized for single particles even in dense environments. As the surface concentration increases, the diffusion coefficient drops, and when the concentration reaches a critical threshold, the nanoparticles are essentially frozen. Financial support from NSF DMR-1619651 is acknowledged.

Nanoparticle Vaccines Adopting Virus-like Features for Enhanced Immune Potentiation

PubMed Central

Chattopadhyay, Saborni; Chen, Jui-Yi; Chen, Hui-Wen; Hu, Che-Ming Jack

2017-01-01

Synthetic nanoparticles play an increasingly significant role in vaccine design and development as many nanoparticle vaccines show improved safety and efficacy over conventional formulations. These nanoformulations are structurally similar to viruses, which are nanoscale pathogenic organisms that have served as a key selective pressure driving the evolution of our immune system. As a result, mechanisms behind the benefits of nanoparticle vaccines can often find analogue to the interaction dynamics between the immune system and viruses. This review covers the advances in vaccine nanotechnology with a perspective on the advantages of virus mimicry towards immune potentiation. It provides an overview to the different types of nanomaterials utilized for nanoparticle vaccine development, including functionalization strategies that bestow nanoparticles with virus-like features. As understanding of human immunity and vaccine mechanisms continue to evolve, recognizing the fundamental semblance between synthetic nanoparticles and viruses may offer an explanation for the superiority of nanoparticle vaccines over conventional vaccines and may spur new design rationales for future vaccine research. These nanoformulations are poised to provide solutions towards pressing and emerging human diseases. PMID:29071191

Assessment of the cytotoxicity of aluminium oxide nanoparticles on selected mammalian cells.

PubMed

Radziun, E; Dudkiewicz Wilczyńska, J; Książek, I; Nowak, K; Anuszewska, E L; Kunicki, A; Olszyna, A; Ząbkowski, T

2011-12-01

The rapid development of nanotechnology raises both enthusiasm and anxiety among researchers, which is related to the safety use of the manufactured materials. Thus, the aim of this study was to investigate the effect of aluminium oxide nanoparticles on the viability of selected mammalian cells in vitro. The aluminium oxide nanoparticles were characterised using SEM and BET analyses. Based on Zeta (ζ) potential measurements and particle size distribution, the tested suspensions of aluminium oxide nanoparticles in water and nutrient solutions with or without FBS were classified as unstable. Cell viability, the degree of apoptosis induction and nanoparticles internalization into the cells were assessed after 24 h of cell exposure to Al2O3 nanoparticles. Our results confirm the ability of aluminium oxide nanoparticles to penetrate through the membranes of L929 and BJ cells. Despite this, there was no significant increase in apoptosis or decrease in cell viability observed, suggesting that aluminium oxide nanoparticles in the tested range of concentrations has no cytotoxic effects on the selected mammalian cells. Copyright © 2011 Elsevier Ltd. All rights reserved.

Protein nanoparticles as drug delivery carriers for cancer therapy.

PubMed

Lohcharoenkal, Warangkana; Wang, Liying; Chen, Yi Charlie; Rojanasakul, Yon

2014-01-01

Nanoparticles have increasingly been used for a variety of applications, most notably for the delivery of therapeutic and diagnostic agents. A large number of nanoparticle drug delivery systems have been developed for cancer treatment and various materials have been explored as drug delivery agents to improve the therapeutic efficacy and safety of anticancer drugs. Natural biomolecules such as proteins are an attractive alternative to synthetic polymers which are commonly used in drug formulations because of their safety. In general, protein nanoparticles offer a number of advantages including biocompatibility and biodegradability. They can be prepared under mild conditions without the use of toxic chemicals or organic solvents. Moreover, due to their defined primary structure, protein-based nanoparticles offer various possibilities for surface modifications including covalent attachment of drugs and targeting ligands. In this paper, we review the most significant advancements in protein nanoparticle technology and their use in drug delivery arena. We then examine the various sources of protein materials that have been used successfully for the construction of protein nanoparticles as well as their methods of preparation. Finally, we discuss the applications of protein nanoparticles in cancer therapy.

DNA nanotechnology-based composite-type gold nanoparticle-immunostimulatory DNA hydrogel for tumor photothermal immunotherapy.

PubMed

Yata, Tomoya; Takahashi, Yuki; Tan, Mengmeng; Nakatsuji, Hirotaka; Ohtsuki, Shozo; Murakami, Tatsuya; Imahori, Hiroshi; Umeki, Yuka; Shiomi, Tomoki; Takakura, Yoshinobu; Nishikawa, Makiya

2017-11-01

Success of tumor photothermal immunotherapy requires a system that induces heat stress in cancer cells and enhances strong anti-tumor immune responses. Here, we designed a composite-type immunostimulatory DNA hydrogel consisting of a hexapod-like structured DNA (hexapodna) with CpG sequences and gold nanoparticles. Mixing of the properly designed hexapodna and oligodeoxynucleotide-modified gold nanoparticles resulted in the formation of composite-type gold nanoparticle-DNA hydrogels. Laser irradiation of the hydrogel resulted in the release of hexapodna, which efficiently stimulated immune cells to release proinflammatory cytokines. Then, EG7-OVA tumor-bearing mice received an intratumoral injection of a gold nanoparticle-DNA hydrogel, followed by laser irradiation at 780 nm. This treatment increased the local temperature and the mRNA expression of heat shock protein 70 in the tumor tissue, increased tumor-associated antigen-specific IgG levels in the serum, and induced tumor-associated antigen-specific interferon-γ production from splenocytes. Moreover, the treatment significantly retarded the tumor growth and extended the survival of the tumor-bearing mice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nanoparticle targeting of Gram-positive and Gram-negative bacteria for magnetic-based separations of bacterial pathogens

NASA Astrophysics Data System (ADS)

Lu, Hoang D.; Yang, Shirley S.; Wilson, Brian K.; McManus, Simon A.; Chen, Christopher V. H.-H.; Prud'homme, Robert K.

2017-04-01

Antimicrobial resistance is a healthcare problem of increasing significance, and there is increasing interest in developing new tools to address bacterial infections. Bacteria-targeting nanoparticles hold promise to improve drug efficacy, compliance, and safety. In addition, nanoparticles can also be used for novel applications, such as bacterial imaging or bioseperations. We here present the use of a scalable block-copolymer-directed self-assembly process, Flash NanoPrecipitation, to form zinc(II)-bis(dipicolylamine) modified nanoparticles that bind to both Gram-positive and Gram-negative bacteria with specificity. Particles have tunable surface ligand densities that change particle avidity and binding efficacy. A variety of materials can be encapsulated into the core of the particles, such as optical dyes or iron oxide colloids, to produce imageable and magnetically active bacterial targeting constructs. As a proof-of-concept, these particles are used to bind and separate bacteria from solution in a magnetic column. Magnetic manipulation and separation would translate to a platform for pathogen identification or removal. These magnetic and targeted nanoparticles enable new methods to address bacterial infections.

Light trapping in a-Si/c-Si heterojunction solar cells by embedded ITO nanoparticles at rear surface

NASA Astrophysics Data System (ADS)

Dhar, Sukanta; Mandal, Sourav; Mitra, Suchismita; Ghosh, Hemanta; Mukherjee, Sampad; Banerjee, Chandan; Saha, Hiranmoy; Barua, A. K.

2017-12-01

The advantages of the amorphous silicon (a-Si)/crystalline silicon (c-Si) hetero junction technology are low temperature (<200 °C) processing and fewer process steps to fabricate the device. In this work, we used indium tin oxide (ITO) nanoparticles embedded in amorphous silicon material at the rear side of the crystalline wafer. The nanoparticles were embedded in silicon to have higher scattering efficiency, as has been established by simulation studies. It has been shown that significant photocurrent enhancements (32.8 mA cm-2 to 35.1 mA cm-2) are achieved because of high scattering and coupling efficiency of the embedded nanoparticles into the silicon device, leading to an increase in efficiency from 13.74% to 15.22%. In addition, we have observed a small increase in open circuit voltage. This may be due to the surface passivation during the ITO nanoparticle formation with hydrogen plasma treatment. We also support our experimental results by simulation, with the help of a commercial finite-difference time-domain (FDTD) software solution.

Silver deposited carboxymethyl chitosan-grafted magnetic nanoparticles as dual action deliverable antimicrobial materials.

PubMed

Vo, Duc-Thang; Sabrina, Sabrina; Lee, Cheng-Kang

2017-04-01

Carboxymethyl chitosan (CMCS) was known to have a much better antimicrobial activity than chitosan due to the increased cationic -NH 3 + groups resulted from the intra- and intermolecular interactions between the carboxyl and amino groups. CMCS was grafted onto the surface of silica coated magnetic nanoparticles (MNPs) to obtain magnetically retrievable and deliverable antimicrobial nanoparticles (MNPs@CMCS). The presence of carboxylate groups in CMCS not only enhanced antimicrobial activity but also enabled Ag ions chelating ability to induce the in situ formation of Ag nanoparticles (AgNPs). The deposition of AgNPs on the surface of MNPs@CMCS could significantly increase its antimicrobial activity against planktonic cells due to the dual action of CMCS and AgNPs. Due to its high magnetism, the as-prepared MNPs@CMCS-Ag could be efficiently delivered into an existing biofilm under the guidance of an applied magnetic field. Without direct contact, the Ag ions and/or radical oxygen species (ROS) released from the deposited Ag nanoparticles could effectively kill the bacteria embedded in the extracellular polymeric substances (EPS) matrix of biofilm. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of gold nanoparticles on the electro-optical properties of a polymer dispersed liquid crystal

NASA Astrophysics Data System (ADS)

Hinojosa, A.; Shive, C.; Sharma, Suresh

2010-03-01

We have studied the electro-optical properties of a polymer-dispersed liquid crystal (PDLC) as functions of relative concentrations of gold nanoparticles. PDLC samples were synthesized between indium-tin-oxide (ITO) coated glass slides, separated by SiO2 spacers, by using liquid crystal E44, a monofunctional acrylic oligomer (CN135), and a tetrafunctional crosslinker (SR295). A UV photoinitiator (SR1124) was used to facilitate the curing of the monomer exposed to UV radiation from a Hg spectral lamp. A He-Ne laser was used to measure optical transmission through the PDLC as a function of applied ac electric field (1 kHz). The PDLC without gold nanoparticles shows the expected behavior; transmission through the PDLC increases from a minimum (opaque) to a maximum (transparent) with increasing electric field. The electro-optical behavior of the PDLC is altered significantly (e. g., relatively low switching field) upon addition of relatively low concentrations of gold nanoparticles into the starting PDLC syrup. We present electro-optical data as functions of gold nanoparticle concentration and discuss possible mechanism to understand our results.

One stone, two birds: silica nanospheres significantly increase photocatalytic activity and colloidal stability of photocatalysts

NASA Astrophysics Data System (ADS)

Rasamani, Kowsalya D.; Foley, Jonathan J., IV; Sun, Yugang

2018-03-01

Silver-doped silver chloride [AgCl(Ag)] nanoparticles represent a unique class of visible-light-driven photocatalysts, in which the silver dopants introduce electron-abundant mid-gap energy levels to lower the bandgap of AgCl. However, free-standing AgCl(Ag) nanoparticles, particularly those with small sizes and large surface areas, exhibit low colloidal stability and low compositional stability upon exposure to light irradiation, leading to easy aggregation and conversion to metallic silver and thus a loss of photocatalytic activity. These problems could be eliminated by attaching the small AgCl(Ag) nanoparticles to the surfaces of spherical dielectric silica particles with submicrometer sizes. The high optical transparency in the visible spectral region (400-800 nm), colloidal stability, and chemical/electronic inertness displayed by the silica spheres make them ideal for supporting photocatalysts and significantly improving their stability. The spherical morphology of the dielectric silica particles can support light scattering resonances to generate significantly enhanced electric fields near the silica particle surfaces, on which the optical absorption cross-section of the AgCl(Ag) nanoparticles is dramatically increased to promote their photocatalytic activity. The hybrid silica/AgCl(Ag) structures exhibit superior photocatalytic activity and stability, suitable for supporting photocatalysis sustainably; for instance, their efficiency in the photocatalytic decomposition of methylene blue decreases by only ˜9% even after ten cycles of operation.

In vitro antioxidant and hepatoprotective potential of Azolla microphylla phytochemically synthesized gold nanoparticles on acetaminophen - induced hepatocyte damage in Cyprinus carpio L.

PubMed

Kunjiappan, Selvaraj; Bhattacharjee, Chiranjib; Chowdhury, Ranjana

2015-06-01

The present study aims to evaluate the hepatoprotective and antioxidant effects of gold nanoparticles (GNaP) biosynthesized through the mediation of Azolla microphylla and A. microphylla extract on acetaminophen-induced hepatocyte damage in common carp fish (Cyprinus carpio L.). The gold nanoparticles (100, 150, 200 μg/ml) and A. microphylla extract powder (100, 200, 400 μg/ml) were added to the primary hepatocytes in different conditions: treatment I (before 12 mM acetaminophen), treatment II (after 12 mM acetaminophen), and treatment III (both before and after 12 mM acetaminophen), and incubated. Among these, control group treated with 12 mM acetaminophen produced significantly elevated levels (50-80%) of lactate dehydrogenase (LDH), catalase (CAT), glutamate oxalate transaminase (GOT), glutamate pyruvate transaminase (GPT), and malondialdehyde (MDA), and significantly decreased the levels (60-75%) of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Treatment with methanol extract of A. microphylla phytochemically biosynthesized gold nanoparticles (100, 150, 200 μg/ml) and A. microphylla methanol extract powder (100, 200, 400 μg/ml) significantly improved the viability of cells in a culture medium. It also significantly reduced the levels of LDH, CAT, GOT, GPT, and MDA, and significantly increased the levels of SOD and GSH-Px. In conclusion, gold nanoparticles biosynthesized through A. microphylla demonstrated effective hepatoprotective and antioxidant effects than methanol extract of A. microphylla.

Protective effects of platinum nanoparticles against UV-light-induced epidermal inflammation.

PubMed

Yoshihisa, Yoko; Honda, Ayumi; Zhao, Qing-Li; Makino, Teruhiko; Abe, Riichiro; Matsui, Kotaro; Shimizu, Hiroshi; Miyamoto, Yusei; Kondo, Takashi; Shimizu, Tadamichi

2010-11-01

Intracellular reactive oxygen species (ROS) and apoptosis play important roles in the ultraviolet (UV)-induced inflammatory responses in the skin. Metal nanoparticles have been developed to increase the catalytic activity of metals, which is because of the large surface area of smaller particles. Platinum nanoparticles (nano-Pt) protected by poly acrylic acid were manufactured by reduction with ethanol. A marked increase in ROS production was observed in UV-treated HaCaT keratinocytes cell lines, while a decrease in ROS production was observed in nano-Pt-treated cells. Pretreatment of the cells with nano-Pt also caused a significant inhibition of UVB- and UVC-induced apoptosis. Furthermore, we found that mice treated with nano-Pt gel prior to UV irradiation showed significant inhibition of UVB-induced inflammation and UVA-induced photoallergy compared to UV-irradiated control mice. These results suggest that nano-Pt effectively protects against UV-induced inflammation by decreasing ROS production and inhibiting apoptosis in keratinocytes. © 2010 John Wiley & Sons A/S.

An interdisciplinary computational/experimental approach to evaluate drug-loaded gold nanoparticle tumor cytotoxicity

PubMed Central

Curtis, Louis T; England, Christopher G; Wu, Min; Lowengrub, John; Frieboes, Hermann B

2016-01-01

Aim: Clinical translation of cancer nanotherapy has largely failed due to the infeasibility of optimizing the complex interaction of nano/drug/tumor/patient parameters. We develop an interdisciplinary approach modeling diffusive transport of drug-loaded gold nanoparticles in heterogeneously-vascularized tumors. Materials & methods: Evaluated lung cancer cytotoxicity to paclitaxel/cisplatin using novel two-layer (hexadecanethiol/phosphatidylcholine) and three-layer (with high-density-lipoprotein) nanoparticles. Computer simulations calibrated to in-vitro data simulated nanotherapy of heterogeneously-vascularized tumors. Results: Evaluation of free-drug cytotoxicity between monolayer/spheroid cultures demonstrates a substantial differential, with increased resistance conferred by diffusive transport. Nanoparticles had significantly higher efficacy than free-drug. Simulations of nanotherapy demonstrate 9.5% (cisplatin) and 41.3% (paclitaxel) tumor radius decrease. Conclusion: Interdisciplinary approach evaluating gold nanoparticle cytotoxicity and diffusive transport may provide insight into cancer nanotherapy. PMID:26829163

Antibacterial activity of silver and zinc nanoparticles against Vibrio cholerae and enterotoxic Escherichia coli

PubMed Central

Salem, Wesam; Leitner, Deborah R.; Zingl, Franz G.; Schratter, Gebhart; Prassl, Ruth; Goessler, Walter; Reidl, Joachim; Schild, Stefan

2015-01-01

Vibrio cholerae and enterotoxic Escherichia coli (ETEC) remain two dominant bacterial causes of severe secretory diarrhea and still a significant cause of death, especially in developing countries. In order to investigate new effective and inexpensive therapeutic approaches, we analyzed nanoparticles synthesized by a green approach using corresponding salt (silver or zinc nitrate) with aqueous extract of Caltropis procera fruit or leaves. We characterized the quantity and quality of nanoparticles by UV–visible wavelength scans and nanoparticle tracking analysis. Nanoparticles could be synthesized in reproducible yields of approximately 108 particles/ml with mode particles sizes of approx. 90–100 nm. Antibacterial activity against two pathogens was assessed by minimal inhibitory concentration assays and survival curves. Both pathogens exhibited similar resistance profiles with minimal inhibitory concentrations ranging between 5 × 105 and 107 particles/ml. Interestingly, zinc nanoparticles showed a slightly higher efficacy, but sublethal concentrations caused adverse effects and resulted in increased biofilm formation of V. cholerae. Using the expression levels of the outer membrane porin OmpT as an indicator for cAMP levels, our results suggest that zinc nanoparticles inhibit adenylyl cyclase activity. This consequently deceases the levels of this second messenger, which is a known inhibitor of biofilm formation. Finally, we demonstrated that a single oral administration of silver nanoparticles to infant mice colonized with V. cholerae or ETEC significantly reduces the colonization rates of the pathogens by 75- or 100-fold, respectively. PMID:25466205

Expression of genes encoding IGFBPs, SNARK, CD36, and PECAM1 in the liver of mice treated with chromium disilicide and titanium nitride nanoparticles.

PubMed

Minchenko, Dmytro O; Tsymbal, D O; Yavorovsky, O P; Solokha, N V; Minchenko, O H

2017-04-25

The aim of the present study was to examine the effect of chromium disilicide and titanium nitride nanoparticles on the expression level of genes encoding important regulatory factors (IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK/NUAK2, CD36, and PECAM1/CD31) in mouse liver for evaluation of possible toxic effects of these nanoparticles. Male mice received 20 mg chromium disilicide nanoparticles (45 nm) and titanium nitride nanoparticles (20 nm) with food every working day for 2 months. The expression of IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver was studied by quantitative polymerase chain reaction. Treatment of mice with chromium disilicide nanoparticles led to down-regulation of the expression of IGFBP2, IGFBP5, PECAM1, and SNARK genes in the liver in comparison with control mice, with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3 and CD36 genes was increased in mouse liver upon treatment with chromium disilicide nanoparticles. We have also shown that treatment with titanium nitride nanoparticles resulted in down-regulation of the expression of IGFBP2 and SNARK genes in the liver with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3, IGFBP4, and CD36 genes was increased in the liver of mice treated with titanium nitride nanoparticles. Furthermore, the effect of chromium disilicide nanoparticles on IGFBP2 and CD36 genes expression was significantly stronger as compared to titanium nitride nanoparticles. The results of this study demonstrate that chromium disilicide and titanium nitride nanoparticles have variable effects on the expression of IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver, which may reflect the genotoxic activities of the studied nanoparticles.

Au 329–xAg x(SR) 84 Nanomolecules: Plasmonic Alloy Faradaurate-329

DOE PAGES

Kumara, Chanaka; Zuo, Xiaobing; Cullen, David A.; ...

2015-08-10

Though significant progress has been made to improve the monodispersity of larger (>10 nm) alloy metal nanoparticles, there still exists a significant variation in nanoparticle composition, ranging from ±1000s of atoms. Here in this paper, for the first time, we report the synthesis of atomically precise (±0 metal atom variation) Au 329–xAg x(SCH 2CH 2Ph) 84 alloy nanomolecules. The composition was determined using high resolution electrospray ionization mass spectrometry. In contrast to larger (>10 nm) Au–Ag nanoparticles, the surface plasmon resonance (SPR) peak does not show a major shift, but a minor ~10 nm red-shift, upon increasing silver content. Themore » intensity of the SPR peak also varies in an intriguing manner, where a dampening is observed with medium silver incorporation, and a significant sharpening is observed upon higher Ag content. The report outlines (a) an unprecedented advance in nanoparticle mass spectrometry of high mass at atomic precision; and (b) the unexpected optical behavior of Au–Ag alloys in the region where nascent SPR emerges; specifically, in this work, the SPR-like peak does not show a major ~100 nm blue-shift with Ag alloying of Au 329 nanomolecules, as shown to be common in larger nanoparticles.« less

Titanium Dioxide Nanoparticle Ingestion Alters Nutrient Absorption in an In Vitro Model of the Small Intestine

PubMed Central

Guo, Zhongyuan; Martucci, Nicole J.; Moreno-Olivas, Fabiola; Tako, Elad; Mahler, Gretchen J.

2017-01-01

Ingestion of titanium dioxide (TiO2) nanoparticles from products such as agricultural chemicals, processed food, and nutritional supplements is nearly unavoidable. The gastrointestinal tract serves as a critical interface between the body and the external environment, and is the site of essential nutrient absorption. The goal of this study was to examine the effects of ingesting the 30 nm TiO2 nanoparticles with an in vitro cell culture model of the small intestinal epithelium, and to determine how acute or chronic exposure to nano-TiO2 influences intestinal barrier function, reactive oxygen species generation, proinflammatory signaling, nutrient absorption (iron, zinc, fatty acids), and brush border membrane enzyme function (intestinal alkaline phosphatase). A Caco-2/HT29-MTX cell culture model was exposed to physiologically relevant doses of TiO2 nanoparticles for acute (four hours) or chronic (five days) time periods. Exposure to TiO2 nanoparticles significantly decreased intestinal barrier function following chronic exposure. Reactive oxygen species (ROS) generation, proinflammatory signaling, and intestinal alkaline phosphatase activity all showed increases in response to nano-TiO2. Iron, zinc, and fatty acid transport were significantly decreased following exposure to TiO2 nanoparticles. This is because nanoparticle exposure induced a decrease in absorptive microvilli in the intestinal epithelial cells. Nutrient transporter protein gene expression was also altered, suggesting that cells are working to regulate the transport mechanisms disturbed by nanoparticle ingestion. Overall, these results show that intestinal epithelial cells are affected at a functional level by physiologically relevant exposure to nanoparticles commonly ingested from food. PMID:28944308

Determining the composition of gold nanoparticles: a compilation of shapes, sizes, and calculations using geometric considerations.

PubMed

Mori, Taizo; Hegmann, Torsten

2016-01-01

Size, shape, overall composition, and surface functionality largely determine the properties and applications of metal nanoparticles. Aside from well-defined metal clusters, their composition is often estimated assuming a quasi-spherical shape of the nanoparticle core. With decreasing diameter of the assumed circumscribed sphere, particularly in the range of only a few nanometers, the estimated nanoparticle composition increasingly deviates from the real composition, leading to significant discrepancies between anticipated and experimentally observed composition, properties, and characteristics. We here assembled a compendium of tables, models, and equations for thiol-protected gold nanoparticles that will allow experimental scientists to more accurately estimate the composition of their gold nanoparticles using TEM image analysis data. The estimates obtained from following the routines described here will then serve as a guide for further analytical characterization of as-synthesized gold nanoparticles by other bulk (thermal, structural, chemical, and compositional) and surface characterization techniques. While the tables, models, and equations are dedicated to gold nanoparticles, the composition of other metal nanoparticle cores with face-centered cubic lattices can easily be estimated simply by substituting the value for the radius of the metal atom of interest.

Preparation and Investigation of Foaming Amphiphilic Fluorinated Nanoparticles for Enhanced Oil Recovery.

PubMed

Wang, Keliang; Wang, Gang; Lu, Chunjing; Pei, Cuiying; Wang, Ying

2017-12-08

Amphiphilic nanoparticles have attracted increasing interest as Pickering emulsifiers owing to the combined advantages of both traditional surfactants and homogeneous particles. Here, foaming amphiphilic fluorinated nanoparticles were prepared for enhanced oil recovery by the toposelective surface modification method. The structure and properties of amphiphilic nanoparticles were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, a laser diffraction method, fluorescence microscopy, a pendant drop tensiometer, and foamscan. It was found that the amphiphilic fluorinated nanoparticles exhibited significant interfacial activity at the air-water interface and generated stabilized aqueous foams against coalescence and drainage even in the absence of surfactants. When the particle concentration reached 0.6 wt %, the adsorption of the amphiphilic nanoparticles at the interface was saturated and the equilibrium surface tension dropped to around 32.7 mN/m. When the particle concentration reached 0.4 wt %, the Gibbs stability criterion was fulfilled. The amphiphilic nanoparticles foam system has a better plugging capacity and enhanced oil recovery capacity. The results obtained provide fundamental insights into the understanding of the self-assembly behavior and foam properties of amphiphilic fluorinated nanoparticles and further demonstrate the future potential of the amphiphilic nanoparticles used as colloid surfactants for enhanced oil recovery applications.

Preparation and Investigation of Foaming Amphiphilic Fluorinated Nanoparticles for Enhanced Oil Recovery

PubMed Central

Wang, Keliang; Lu, Chunjing; Pei, Cuiying; Wang, Ying

2017-01-01

Amphiphilic nanoparticles have attracted increasing interest as Pickering emulsifiers owing to the combined advantages of both traditional surfactants and homogeneous particles. Here, foaming amphiphilic fluorinated nanoparticles were prepared for enhanced oil recovery by the toposelective surface modification method. The structure and properties of amphiphilic nanoparticles were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, a laser diffraction method, fluorescence microscopy, a pendant drop tensiometer, and foamscan. It was found that the amphiphilic fluorinated nanoparticles exhibited significant interfacial activity at the air–water interface and generated stabilized aqueous foams against coalescence and drainage even in the absence of surfactants. When the particle concentration reached 0.6 wt %, the adsorption of the amphiphilic nanoparticles at the interface was saturated and the equilibrium surface tension dropped to around 32.7 mN/m. When the particle concentration reached 0.4 wt %, the Gibbs stability criterion was fulfilled. The amphiphilic nanoparticles foam system has a better plugging capacity and enhanced oil recovery capacity. The results obtained provide fundamental insights into the understanding of the self-assembly behavior and foam properties of amphiphilic fluorinated nanoparticles and further demonstrate the future potential of the amphiphilic nanoparticles used as colloid surfactants for enhanced oil recovery applications. PMID:29292747

Design of ligand-targeted nanoparticles for enhanced cancer targeting

NASA Astrophysics Data System (ADS)

Stefanick, Jared F.

Ligand-targeted nanoparticles are increasingly used as drug delivery vehicles for cancer therapy, yet have not consistently produced successful clinical outcomes. Although these inconsistencies may arise from differences in disease models and target receptors, nanoparticle design parameters can significantly influence therapeutic efficacy. By employing a multifaceted synthetic strategy to prepare peptide-targeted nanoparticles with high purity, reproducibility, and precisely controlled stoichiometry of functionalities, this work evaluates the roles of polyethylene glycol (PEG) coating, ethylene glycol (EG) peptide-linker length, peptide hydrophilicity, peptide density, and nanoparticle size on tumor targeting in a systematic manner. These parameters were analyzed in multiple disease models by targeting human epidermal growth factor receptor 2 (HER2) in breast cancer and very late antigen-4 (VLA-4) in multiple myeloma to demonstrate the widespread applicability of this approach. By increasing the hydrophilicity of the targeting peptide sequence and simultaneously optimizing the EG peptide-linker length, the in vitro cellular uptake of targeted liposomes was significantly enhanced. Specifically, including a short oligolysine chain adjacent to the targeting peptide sequence effectively increased cellular uptake ~80-fold using an EG6 peptide-linker compared to ~10-fold using an EG45 linker. In vivo, targeted liposomes prepared in a traditional manner lacking the oligolysine chain demonstrated similar biodistribution and tumor uptake to non-targeted liposomes. However, by including the oligolysine chain, targeted liposomes using an EG45 linker significantly improved tumor uptake ~8-fold over non-targeted liposomes, while the use of an EG6 linker decreased tumor accumulation and uptake, owing to differences in cellular uptake kinetics, clearance mechanisms, and binding site barrier effects. To further improve tumor targeting and enhance the selectivity of targeted nanoparticles, a dual-receptor targeted approach was evaluated by targeting multiple cell surface receptors simultaneously. Liposomes functionalized with two distinct peptide antagonists to target VLA-4 and Leukocyte Peyer's Patch Adhesion Molecule-1 (LPAM-1) demonstrated synergistically enhanced cellular uptake by cells overexpressing both target receptors and negligible uptake by cells that do not simultaneously express both receptors, providing a strategy to improve selectivity over conventional single receptor-targeted designs. Taken together, this process of systematic optimization of well-defined nanoparticle drug delivery systems has the potential to improve cancer therapy for a broader patient population.

Assessment of Morphological and Functional Changes in Organs of Rats after Intramuscular Introduction of Iron Nanoparticles and Their Agglomerates

PubMed Central

Sizova, Elena; Miroshnikov, Sergey; Yausheva, Elena; Polyakova, Valentina

2015-01-01

The research was performed on male Wistar rats based on assumptions that new microelement preparations containing metal nanoparticles and their agglomerates had potential. Morphological and functional changes in tissues in the injection site and dynamics of chemical element metabolism (25 indicators) in body were assessed after repeated intramuscular injections (total, 7) with preparation containing agglomerate of iron nanoparticles. As a result, iron depot was formed in myosymplasts of injection sites. The quantity of muscle fibers having positive Perls' stain increased with increasing number of injections. However, the concentration of the most chemical elements and iron significantly decreased in the whole skeletal muscle system (injection sites are not included). Consequently, it increased up to the control level after the sixth and the seventh injections. Among the studied organs (liver, kidneys, and spleen), Caspase-3 expression was revealed only in spleen. The expression had a direct dependence on the number of injections. Processes of iron elimination from preparation containing nanoparticles and their agglomerates had different intensity. PMID:25789310

Cell-Penetrating Peptide-Modified Gold Nanoparticles for the Delivery of Doxorubicin to Brain Metastatic Breast Cancer.

PubMed

Morshed, Ramin A; Muroski, Megan E; Dai, Qing; Wegscheid, Michelle L; Auffinger, Brenda; Yu, Dou; Han, Yu; Zhang, Lingjiao; Wu, Meijing; Cheng, Yu; Lesniak, Maciej S

2016-06-06

As therapies continue to increase the lifespan of patients with breast cancer, the incidence of brain metastases has steadily increased, affecting a significant number of patients with metastatic disease. However, a major barrier toward treating these lesions is the inability of therapeutics to penetrate into the central nervous system and accumulate within intracranial tumor sites. In this study, we designed a cell-penetrating gold nanoparticle platform to increase drug delivery to brain metastatic breast cancer cells. TAT peptide-modified gold nanoparticles carrying doxorubicin led to improved cytotoxicity toward two brain metastatic breast cancer cell lines with a decrease in the IC50 of at least 80% compared to free drug. Intravenous administration of these particles led to extensive accumulation of particles throughout diffuse intracranial metastatic microsatellites with cleaved caspase-3 activity corresponding to tumor foci. Furthermore, intratumoral administration of these particles improved survival in an intracranial MDA-MB-231-Br xenograft mouse model. Our results demonstrate the promising application of gold nanoparticles for improving drug delivery in the context of brain metastatic breast cancer.

Effect of spatial confinement on magnetic hyperthermia via dipolar interactions in Fe3O4 nanoparticles for biomedical applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadat, M E; Patel, Ronak; Sookoor, Jason

2014-09-01

In this work, the effect of nanoparticle confinement on the magnetic relaxation of iron oxide (Fe3O4) nanoparticles (NP) was investigated by measuring the hyperthermia heating behavior in high frequency alternating magnetic field. Three different Fe3O4 nanoparticle systems having distinct nanoparticle configurations were studied in terms of magnetic hyperthermia heating rate and DC magnetization. All magnetic nanoparticle (MNP) systems were constructed using equivalent ~10nm diameter NP that were structured differently in terms of configuration, physical confinement, and interparticle spacing. The spatial confinement was achieved by embedding the Fe3O4 nanoparticles in the matrices of the polystyrene spheres of 100 nm, while themore » unconfined was the free Fe3O4 nanoparticles well-dispersed in the liquid via PAA surface coating. Assuming the identical core MNPs in each system, the heating behavior was analyzed in terms of particle freedom (or confinement), interparticle spacing, and magnetic coupling (or dipole-dipole interaction). DC magnetization data were correlated to the heating behavior with different material properties. Analysis of DC magnetization measurements showed deviation from classical Langevin behavior near saturation due to dipole interaction modification of the MNPs resulting in a high magnetic anisotropy. It was found that the Specific Absorption Rate (SAR) of the unconfined nanoparticle systems were significantly higher than those of confined (the MNPs embedded in the polystyrene matrix). This increase of SAR was found to be attributable to high Néel relaxation rate and hysteresis loss of the unconfined MNPs. It was also found that the dipole-dipole interactions can significantly reduce the global magnetic response of the MNPs and thereby decrease the SAR of the nanoparticle systems.« less

Human cytotoxic T-lymphocyte membrane-camouflaged nanoparticles combined with low-dose irradiation: a new approach to enhance drug targeting in gastric cancer.

PubMed

Zhang, Lianru; Li, Rutian; Chen, Hong; Wei, Jia; Qian, Hanqing; Su, Shu; Shao, Jie; Wang, Lifeng; Qian, Xiaoping; Liu, Baorui

2017-01-01

Cell membrane-derived nanoparticles are becoming more attractive because of their ability to mimic many features of their source cells. This study reports on a biomimetic delivery platform based on human cytotoxic T-lymphocyte membranes. In this system, the surface of poly-lactic- co -glycolic acid nanoparticles was camouflaged using T-lymphocyte membranes, and local low-dose irradiation (LDI) was used as a chemoattractant for nanoparticle targeting. The T-lymphocyte membrane coating was verified using dynamic light scattering, transmission electron microscopy, and confocal laser scanning microscopy. This new platform reduced nanoparticle phagocytosis by macrophages to 23.99% ( P =0.002). Systemic administration of paclitaxel-loaded T-lymphocyte membrane-coated nanoparticles inhibited the growth of human gastric cancer by 56.68% in Balb/c nude mice. Application of LDI at the tumor site significantly increased the tumor growth inhibition rate to 88.50%, and two mice achieved complete remission. Furthermore, LDI could upregulate the expression of adhesion molecules in tumor vessels, which is important in the process of leukocyte adhesion and might contribute to the localization of T-lymphocyte membrane-encapsulated nanoparticles in tumors. Therefore, this new drug-delivery platform retained both the long circulation time and tumor site accumulation ability of human cytotoxic T lymphocytes, while local LDI could significantly enhance tumor localization.

Microneedle-mediated transcutaneous immunization with plasmid DNA coated on cationic PLGA nanoparticles.

PubMed

Kumar, Amit; Wonganan, Piyanuch; Sandoval, Michael A; Li, Xinran; Zhu, Saijie; Cui, Zhengrong

2012-10-28

Previously, it was shown that microneedle-mediated transcutaneous immunization with plasmid DNA can potentially induce a stronger immune response than intramuscular injection of the same plasmid DNA. In the present study, we showed that the immune responses induced by transcutaneous immunization by applying plasmid DNA onto a skin area pretreated with solid microneedles were significantly enhanced by coating the plasmid DNA on the surface of cationic nanoparticles. In addition, the net surface charge of the DNA-coated nanoparticles significantly affected their in vitro skin permeation and their ability to induce immune responses in vivo. Transcutaneous immunization with plasmid DNA-coated net positively charged nanoparticles elicited a stronger immune response than with plasmid DNA-coated net negatively charged nanoparticles or by intramuscular immunization with plasmid DNA alone. Transcutaneous immunization with plasmid DNA-coated net positively charged nanoparticles induced comparable immune responses as intramuscular injection of them, but transcutaneous immunization was able to induce specific mucosal immunity and a more balanced T helper type 1 and type 2 response. The ability of the net positively charged DNA-coated nanoparticles to induce a strong immune response through microneedle-mediated transcutaneous immunization may be attributed to their ability to increase the expression of the antigen gene encoded by the plasmid and to more effectively stimulate the maturation of antigen-presenting cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Imposed Environmental Stresses Facilitate Cell-Free Nanoparticle Formation by Deinococcus radiodurans

PubMed Central

2017-01-01

ABSTRACT The biological synthesis of metal nanoparticles has been examined in a wide range of organisms, due to increased interest in green synthesis and environmental remediation applications involving heavy metal ion contamination. Deinococcus radiodurans is particularly attractive for environmental remediation involving metal reduction, due to its high levels of resistance to radiation and other environmental stresses. However, few studies have thoroughly examined the relationships between environmental stresses and the resulting effects on nanoparticle biosynthesis. In this work, we demonstrate cell-free nanoparticle production and study the effects of metal stressor concentrations and identity, temperature, pH, and oxygenation on the production of extracellular silver nanoparticles by D. radiodurans R1. We also report the synthesis of bimetallic silver and gold nanoparticles following the addition of a metal stressor (silver or gold), highlighting how production of these particles is enabled through the application of environmental stresses. Additionally, we found that both the morphology and size of monometallic and bimetallic nanoparticles were dependent on the environmental stresses imposed on the cells. The nanoparticles produced by D. radiodurans exhibited antimicrobial activity comparable to that of pure silver nanoparticles and displayed catalytic activity comparable to that of pure gold nanoparticles. Overall, we demonstrate that biosynthesized nanoparticle properties can be partially controlled through the tuning of applied environmental stresses, and we provide insight into how their application may affect nanoparticle production in D. radiodurans during bioremediation. IMPORTANCE Biosynthetic production of nanoparticles has recently gained prominence as a solution to rising concerns regarding increased bacterial resistance to antibiotics and a desire for environmentally friendly methods of bioremediation and chemical synthesis. To date, a range of organisms have been utilized for nanoparticle formation. The extremophile D. radiodurans, which can withstand significant environmental stresses and therefore is more robust for metal reduction applications, has yet to be exploited for this purpose. Thus, this work improves our understanding of the impact of environmental stresses on biogenic nanoparticle morphology and composition during metal reduction processes in this organism. This work also contributes to enhancing the controlled synthesis of nanoparticles with specific attributes and functions using biological systems. PMID:28687649

Imposed Environmental Stresses Facilitate Cell-Free Nanoparticle Formation by Deinococcus radiodurans.

PubMed

Chen, Angela; Contreras, Lydia M; Keitz, Benjamin K

2017-09-15

The biological synthesis of metal nanoparticles has been examined in a wide range of organisms, due to increased interest in green synthesis and environmental remediation applications involving heavy metal ion contamination. Deinococcus radiodurans is particularly attractive for environmental remediation involving metal reduction, due to its high levels of resistance to radiation and other environmental stresses. However, few studies have thoroughly examined the relationships between environmental stresses and the resulting effects on nanoparticle biosynthesis. In this work, we demonstrate cell-free nanoparticle production and study the effects of metal stressor concentrations and identity, temperature, pH, and oxygenation on the production of extracellular silver nanoparticles by D. radiodurans R1. We also report the synthesis of bimetallic silver and gold nanoparticles following the addition of a metal stressor (silver or gold), highlighting how production of these particles is enabled through the application of environmental stresses. Additionally, we found that both the morphology and size of monometallic and bimetallic nanoparticles were dependent on the environmental stresses imposed on the cells. The nanoparticles produced by D. radiodurans exhibited antimicrobial activity comparable to that of pure silver nanoparticles and displayed catalytic activity comparable to that of pure gold nanoparticles. Overall, we demonstrate that biosynthesized nanoparticle properties can be partially controlled through the tuning of applied environmental stresses, and we provide insight into how their application may affect nanoparticle production in D. radiodurans during bioremediation. IMPORTANCE Biosynthetic production of nanoparticles has recently gained prominence as a solution to rising concerns regarding increased bacterial resistance to antibiotics and a desire for environmentally friendly methods of bioremediation and chemical synthesis. To date, a range of organisms have been utilized for nanoparticle formation. The extremophile D. radiodurans , which can withstand significant environmental stresses and therefore is more robust for metal reduction applications, has yet to be exploited for this purpose. Thus, this work improves our understanding of the impact of environmental stresses on biogenic nanoparticle morphology and composition during metal reduction processes in this organism. This work also contributes to enhancing the controlled synthesis of nanoparticles with specific attributes and functions using biological systems. Copyright © 2017 American Society for Microbiology.

Improvement of in vitro and in vivo antileishmanial activities of 2', 6'-dihydroxy-4'-methoxychalcone by entrapment in poly(D,L-lactide) nanoparticles.

PubMed

Torres-Santos, E C; Rodrigues, J M; Moreira, D L; Kaplan, M A; Rossi-Bergmann, B

1999-07-01

The inhibition of intracellular Leishmania amazonensis growth by 2', 6'-dihydroxy-4'-methoxychalcone (DMC) isolated from Piper aduncum was further enhanced after encapsulation of DMC in polymeric nanoparticles. Encapsulated DMC also showed increased antileishmanial activity in infected BALB/c mice, as evidenced by significantly smaller lesions and fewer parasites in the lesions.

Investigation of peanut oral immunotherapy with CpG/peanut nanoparticles in a murine model of peanut allergy.

PubMed

Srivastava, Kamal D; Siefert, Alyssa; Fahmy, Tarek M; Caplan, Michael J; Li, Xiu-Min; Sampson, Hugh A

2016-08-01

Treatments to reverse peanut allergy remain elusive. Current clinical approaches using peanut oral/sublingual immunotherapy are promising, but concerns about safety and long-term benefit remain a barrier to wide use. Improved methods of delivering peanut-specific immunotherapy are needed. We sought to investigate the efficacy and safety of peanut oral immunotherapy using CpG-coated poly(lactic-co-glycolic acid) nanoparticles containing peanut extract (CpG/PN-NPs) in a murine model of peanut allergy. C3H/HeJ mice were rendered peanut allergic by means of oral sensitization with peanut and cholera toxin. Mice were then subjected to 4 weekly gavages with CpG/PN-NPs, vehicle (PBS), nanoparticles alone, peanut alone, CpG nanoparticles, or peanut nanoparticles. Untreated mice served as naive controls. After completing therapy, mice underwent 5 monthly oral peanut challenges. Anaphylaxis was evaluated by means of visual assessment of symptom scores and measurement of body temperature and plasma histamine levels. Peanut-specific serum IgE, IgG1, and IgG2a levels were measured by using ELISA, as were cytokine recall responses in splenocyte cultures. Mice with peanut allergy treated with CpG/PN-NPs but not vehicle or other treatment components were significantly protected from anaphylaxis to all 5 oral peanut challenges, as indicated by lower symptom scores, less change in body temperature, and a lower increase of plasma histamine levels. Importantly, CpG/PN-NP treatment did not cause anaphylactic reactions. Treatment was associated with a sustained and significant decrease in peanut-specific IgE/IgG1 levels and an increase in peanut-specific IgG2a levels. Compared with vehicle control animals, peanut recall responses in splenocyte cultures from nanoparticle-treated mice showed significantly decreased levels of TH2 cytokines (IL-4, IL-5, and IL-13) but increased IFN-γ levels in cell supernatants. Preclinical findings indicate that peanut oral immunotherapy with CpG/PN-NPs might be a valuable strategy for peanut-specific immunotherapy in human subjects. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Pulmonary Nanoparticle Exposure Disrupts Systemic Microvascular Nitric Oxide Signaling

PubMed Central

Nurkiewicz, Timothy R.; Porter, Dale W.; Hubbs, Ann F.; Stone, Samuel; Chen, Bean T.; Frazer, David G.; Boegehold, Matthew A.; Castranova, Vincent

2009-01-01

We have shown that pulmonary nanoparticle exposure impairs endothelium dependent dilation in systemic arterioles. However, the mechanism(s) through which this effect occurs is/are unclear. The purpose of this study was to identify alterations in the production of reactive species and endogenous nitric oxide (NO) after nanoparticle exposure, and determine the relative contribution of hemoproteins and oxidative enzymes in this process. Sprague-Dawley rats were exposed to fine TiO2 (primary particle diameter ∼1 μm) and TiO2 nanoparticles (primary particle diameter ∼21 nm) via aerosol inhalation at depositions of 4–90 μg per rat. As in previous intravital experiments in the spinotrapezius muscle, dose-dependent arteriolar dilations were produced by intraluminal infusions of the calcium ionophore A23187. Nanoparticle exposure robustly attenuated these endothelium-dependent responses. However, this attenuation was not due to altered microvascular smooth muscle NO sensitivity because nanoparticle exposure did not alter arteriolar dilations in response to local sodium nitroprusside iontophoresis. Nanoparticle exposure significantly increased microvascular oxidative stress by ∼60%, and also elevated nitrosative stress fourfold. These reactive stresses coincided with a decreased NO production in a particle deposition dose-dependent manner. Radical scavenging, or inhibition of either myeloperoxidase or nicotinamide adenine dinucleotide phosphate oxidase (reduced) oxidase partially restored NO production as well as normal microvascular function. These results indicate that in conjunction with microvascular dysfunction, nanoparticle exposure also decreases NO bioavailability through at least two functionally distinct mechanisms that may mutually increase local reactive species. PMID:19270016

In Vivo Biodistribution and Pharmacokinetics of Silica Nanoparticles as a Function of Geometry, Porosity and Surface Characteristics

PubMed Central

Yu, Tian; Hubbard, Dallin; Ray, Abhijit; Ghandehari, Hamidreza

2012-01-01

The in vivo biodistribution and pharmacokinetics of silica nanoparticles (SiO2) with systematically varied geometries, porosities, and surface characteristics were investigated in immune-competent CD-1 mice via the intravenous injection. The nanoparticles were taken up extensively by the liver and spleen. Mesoporous SiO2 exhibited higher accumulation in the lung than nonporous SiO2 of similar size. This accumulation was reduced by primary amine modification of the nanoparticles. High aspect ratio, amine-modified mesoporous nanorods showed enhanced lung accumulation compared to amine-modified mesoporous nanospheres. Accumulation of the nanoparticles was mainly caused by passive entrapment in the discontinuous openings in the endothelium of the liver and spleen or in the pulmonary capillaries, and was highly dependent on nanoparticle hydrodynamic size in circulation. The SiO2 were likely internalized by the reticulo-endothelial system (RES) following physical sequestration in the liver and spleen. The nanoparticles that were transiently associated with the lung were re-distributed out of this organ without significant internalization. Pharmacokinetic analysis showed that all SiO2 were rapidly cleared from systemic circulation. Amine-modified or nonporous nanoparticles possessed a higher volume of distribution at steady state than their pristine counterparts or mesoporous SiO2. In all, surface characteristics and porosity played important roles in influencing SiO2 biodistribution and pharmacokinetics. Increasing the aspect ratio of amine-modified mesoporous SiO2 from 1 to 8 resulted in increased accumulation in the lung. PMID:22684119

Can a novel silver nano coating reduce infections and maintain cell viability in vitro?

PubMed

Qureshi, Ammar T; Landry, Jace P; Dasa, Vinod; Janes, Marlene; Hayes, Daniel J

2014-03-01

Herein we report a facile layer-by-layer method for creating an antimicrobial coating composed of silver nanoparticles on medical grade titanium test discs. Nanoscale silver nanoparticle layers are attached to the titanium orthopedic implant material via aminopropyltriethoxy silane crosslinker that reacts with neighboring silane moieties to create an interconnected network. A monolayer of silane, followed by a monolayer of silver nanoparticles would form one self-assembled layer and this process can be repeated serially, resulting in increased silver nanoparticles deposition. The release rate of silver ion increases predictably with increasing numbers of layers and at appropriate thicknesses these coatings demonstrate 3-4 log reduction of viable Escherichia coli and Staphylococcus aureus bacteria. Increasing the thickness of the coatings resulted in reduced bacterial colonization as determined by fluorescent staining and image analysis. Interestingly, the cytotoxicity of murine 3T3 cells as quantified by fluorescent staining and flow cytometry, was minimal and did not vary significantly with the coating thickness. Additionally, these coatings are mechanically stable and resist delamination by orthogonal stress test. This simple layer-by-layer coating technique may provide a cost-effective and biocompatible method for reducing microbial colonization of implantable orthopedic devices.

Investigation of discharged aerosol nanoparticles during chemical precipitation and spray pyrolysis for developing safety measures in the nano research laboratory.

PubMed

Kolesnikov, Еvgeny; Karunakaran, Gopalu; Godymchuk, Anna; Vera, Levina; Yudin, Andrey Grigorjevich; Gusev, Alexander; Kuznetsov, Denis

2017-05-01

Nowadays, the demands for the nanoparticles are increasing due to their tremendous applications in various fields. As a consequence, the discharge of nanoparticles into the atmosphere and environment is also increasing, posing a health threat and environmental damage in terms of pollution. Thus, an extensive research is essential to evaluate the discharge of these nanoparticles into the environment. Keeping this in mind, the present investigation aimed to analyze the discharge of aerosol nanoparticles that are synthesized in the laboratory via chemical precipitation and spray pyrolysis methods. The results indicated that the chemical precipitation method discharges a higher concentration of nanoparticles in the work site when compared to the spray pyrolysis method. The aerosol concentration also varied with the different steps involved during the synthesis of nanoparticles. The average particle's concentration in air for chemical precipitation and spray pyrolysis methods was around 1,037,476 and 883,421particles/cm 3 . In addition, the average total discharge of nanoparticles in the entire laboratory was also examined. A significant variation in the concentration of nanoparticles was noticed, during the processing of materials and the concentration of particles (14-723nm) exceeding the daily allowed concentration to about 70-170 times was observed over a period of 6 months. Thus, the results of the present study will be very useful in developing safety measures and would help in organizing the rules for people working in nanotechnology laboratories to minimize the hazardous effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Responses of Ceriodaphnia dubia to TiO2 and Al2O3 nanoparticles: a dynamic nano-toxicity assessment of energy budget distribution.

PubMed

Li, Minghua; Czymmek, Kirk J; Huang, C P

2011-03-15

The in vivo responses of C. dubia to nanoparticles exemplified by a photoactive titanium oxide (TiO(2)) and a non-photocatalytic aluminum oxide (Al(2)O(3)) were studied. Both nanomaterials inhibited the growth of C. dubia at concentrations ca. >100mg/L. The EC50 value was 42 and 45 mg/L in the presence of TiO(2) and Al(2)O(3), respectively, based on 3-brood reproduction assay. Results implied that reactive oxygen species (ROS) may not be totally responsible for the adverse effects exerted on the invertebrate. Aggregation and interaction among nanoparticles, C. dubia, and algal cells, major food source of Daphnia, played a significant role on the responses of C. dubia to nanoparticles. Dynamic energy budget (DEB) analysis was used to assess the impact of nanoparticles on the energy allocation of C. dubia. Results indicated that nanoparticles could disrupt the assimilation and consumption of energy in C. dubia dramatically. The assimilation energy was negatively correlated to the concentration of nanomaterials, a reduction from 11 to near 0 μg-C/animal/day in the presence of TiO(2) or Al(2)O(3) nanoparticles at a nanoparticle concentration of 200mg/L. The energy consumed for life-maintenance increased also with increase in the concentration of nanomaterials. Results clearly demonstrated the importance of energy disruption in determining the toxicity of nanoparticles toward C. dubia. Copyright © 2011 Elsevier B.V. All rights reserved.

[Health effects of nanoparticles and nanomaterials (II) methods for measurement of nanoparticles and their presence in the air].

PubMed

Fujitani, Yuji; Hirano, Seishiro

2008-05-01

The mass concentrations of airborne particles in the atmospheric, indoor, and industrial environments are regulated by air quality standards. Epidemiological studies show that there are significant positive correlations between particle mass concentrations and adverse health effects. In this context nanoparticles in the air, which are defined as particles with a diameter (Dp) of less than 50 nm or 100 nm for engineered ones, are gaining increasing attention despite a small contribution to the mass of total airborn particles. Contrary to the mass concentration the number concentrations of atmospheric nanoparticles are quite high in most cases. Moreover there is limited toxicological information on nanoparticles, although the deposition rate of nanoparticles in the respiratory region is known to be relatively high. Accordingly there are a lot of debates about what metric is best to depict the size distribution of nanoparticles, number, surface area, or mass. In this paper, we report methods for measurement of nanoparticles on the basis of those metrics. We also report sources of nanoparticle in the environment and occupational settings. The high number concentration of nanoparticles of 20-30 nm modal diameters have been documented at roadsides. Diesel-powered vehicles are major sources of those nanoparticles in the urban atmosphere. Engineered nanoparticles generate in some occupational settings in the handling processes such as bagging and cleaning with vacuum cleaners.

In Vitro and In Vivo Characterization of Drug Nanoparticles Prepared Using PureNano™ Continuous Crystallizer to Improve the Bioavailability of Poorly Water Soluble Drugs.

PubMed

Tahara, Kohei; Nishikawa, Masahiro; Matsui, Ko; Hisazumi, Koji; Onodera, Risako; Tozuka, Yuichi; Takeuchi, Hirofumi

2016-09-01

The aim of this study was to enhance the dissolution and oral absorption of poorly water-soluble active pharmaceutical ingredients (APIs) using nanoparticle suspensions prepared with a PureNano™ continuous crystallizer (PCC). Nanoparticle suspensions were prepared with a PCC, which is based on microfluidics reaction technology and solvent-antisolvent crystallization. Phenytoin, bezafibrate, flurbiprofen, and miconazole were used as model APIs. These APIs were dissolved in ethanol and precipitated by the addition of water and polyvinyl alcohol. Batch crystallization (BC) using a beaker was also performed to prepare the suspensions. Both PCC and BC formulations were freeze-dried before being characterized in vitro and in vivo. The particle sizes of the nanoparticle suspensions prepared with the PCC were smaller than those prepared by BC. The dissolution rate of each API in vitro significantly increased after crystallization. Reducing the particle size of either the BC or PCC formulation led to increased API flux across Caco-2 cell monolayers. PCC preparations showed higher plasma concentrations after oral administration, demonstrating the advantages of a fast dissolution rate and increased interaction with the gastrointestinal tract owing to the smaller particle size. PCC can continuously produce nanoparticle APIs and is an efficient approach for improving their oral bioavailability.

Glycyrrhetinic acid-modified chitosan nanoparticles enhanced the effect of 5-fluorouracil in murine liver cancer model via regulatory T-cells

PubMed Central

Cheng, Mingrong; Xu, Hongzhi; Wang, Yong; Chen, Houxiang; He, Bing; Gao, Xiaoyan; Li, Yingchun; Han, Jiang; Zhang, Zhiping

2013-01-01

Modified chitosan nanoparticles are a promising platform for drug, such as 5-fluorouracil (5-FU), gene, and vaccine delivery. Here, we used chitosan and hepatoma cell-specific binding molecule glycyrrhetinic acid (GA) to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by infrared spectroscopy and hydrogen nuclear magnetic resonance. By combining GA-CTS and 5-FU, we obtained a GA-CTS/5-FU nanoparticle, with a particle size of 193.7 nm, drug loading of 1.56%, and a polydispersity index of 0.003. The GA-CTS/5-FU nanoparticle provided a sustained-release system comprising three distinct phases of quick, steady, and slow release. In vitro data indicated that it had a dose- and time-dependent anticancer effect. The effective drug exposure time against hepatic cancer cells was increased in comparison with that observed with 5-FU. In vivo studies on an orthotropic liver cancer mouse model demonstrated that GA-CTS/5-FU significantly inhibited cancer cell proliferation, resulting in increased survival time. The antitumor mechanisms for GA-CTS/5-FU nanoparticle were possibly associated with an increased expression of regulatory T-cells, decreased expression of cytotoxic T-cell and natural killer cells, and reduced levels of interleukin-2 and interferon gamma. PMID:24187487

Combined photothermal therapy and magneto-motive ultrasound imaging using multifunctional nanoparticles

NASA Astrophysics Data System (ADS)

Mehrmohammadi, Mohammad; Ma, Li L.; Chen, Yun-Sheng; Qu, Min; Joshi, Pratixa; Chen, Raeanna M.; Johnston, Keith P.; Emelianov, Stanislav

2010-02-01

Photothermal therapy is a laser-based non-invasive technique for cancer treatment. Photothermal therapy can be enhanced by employing metal nanoparticles that absorb the radiant energy from the laser leading to localized thermal damages. Targeting of nanoparticles leads to more efficient uptake and localization of photoabsorbers thus increasing the effectiveness of the treatment. Moreover, efficient targeting can reduce the required dosage of photoabsorbers; thereby reducing the side effects associated with general systematic administration of nanoparticles. Magnetic nanoparticles, due to their small size and response to an external magnetic field gradient have been proposed for targeted drug delivery. In this study, we investigate the applicability of multifunctional nanoparticles (e.g., magneto-plasmonic nanoparticles) and magneto-motive ultrasound imaging for image-guided photothermal therapy. Magneto-motive ultrasound imaging is an ultrasound based imaging technique capable of detecting magnetic nanoparticles indirectly by utilizing a high strength magnetic field to induce motion within the magnetically labeled tissue. The ultrasound imaging is used to detect the internal tissue motion. Due to presence of the magnetic component, the proposed multifunctional nanoparticles along with magneto-motive ultrasound imaging can be used to detect the presence of the photo absorbers. Clearly the higher concentration of magnetic carriers leads to a monotonic increase in magneto-motive ultrasound signal. Thus, magnetomotive ultrasound can determine the presence of the hybrid agents and provide information about their location and concentration. Furthermore, the magneto-motive ultrasound signal can indicate the change in tissue elasticity - a parameter that is expected to change significantly during the photothermal therapy. Therefore, a comprehensive guidance and assessment of the photothermal therapy may be feasible through magneto-motive ultrasound imaging and magnetoplasmonic nanoparticles.

Increased apoptotic potential and dose-enhancing effect of gold nanoparticles in combination with single-dose clinical electron beams on tumor-bearing mice.

PubMed

Chang, Meng-Ya; Shiau, Ai-Li; Chen, Yu-Hung; Chang, Chih-Jui; Chen, Helen H-W; Wu, Chao-Liang

2008-07-01

High atomic number material, such as gold, may be used in conjunction with radiation to provide dose enhancement in tumors. In the current study, we investigated the dose-enhancing effect and apoptotic potential of gold nanoparticles in combination with single-dose clinical electron beams on B16F10 melanoma tumor-bearing mice. We revealed that the accumulation of gold nanoparticles was detected inside B16F10 culture cells after 18 h of incubation, and moreover, the gold nanoparticles were shown to be colocalized with endoplasmic reticulum and Golgi apparatus in cells. Furthermore, gold nanoparticles radiosensitized melanoma cells in the colony formation assay (P = 0.02). Using a B16F10 tumor-bearing mouse model, we further demonstrated that gold nanoparticles in conjunction with ionizing radiation significantly retarded tumor growth and prolonged survival compared to the radiation alone controls (P < 0.05). Importantly, an increase of apoptotic signals was detected inside tumors in the combined treatment group (P < 0.05). Knowing that radiation-induced apoptosis has been considered a determinant of tumor responses to radiation therapy, and the length of tumor regrowth delay correlated with the extent of apoptosis after single-dose radiotherapy, these results may suggest the clinical potential of gold nanoparticles in improving the outcome of melanoma radiotherapy.

TiO2 nanoparticles and bulk material stimulate human peripheral blood mononuclear cells☆

PubMed Central

Becker, Kathrin; Schroecksnadel, Sebastian; Geisler, Simon; Carriere, Marie; Gostner, Johanna M.; Schennach, Harald; Herlin, Nathalie; Fuchs, Dietmar

2014-01-01

Nanomaterials are increasingly produced and used throughout recent years. Consequently the probability of exposure to nanoparticles has risen. Because of their small 1–100 nm size, the physicochemical properties of nanomaterials may differ from standard bulk materials and may pose a threat to human health. Only little is known about the effects of nanoparticles on the human immune system. In this study, we investigated the effects of TiO2 nanoparticles and bulk material in the in vitro model of human peripheral blood mononuclear cells (PBMC) and cytokine-induced neopterin formation and tryptophan breakdown was monitored. Both biochemical processes are closely related to the course of diseases like infections, atherogenesis and neurodegeneration. OCTi60 (25 nm diameter) TiO2 nanoparticles and bulk material increased neopterin production in unstimulated PBMC and stimulated cells significantly, the effects were stronger for OCTi60 compared to bulk material, while P25 TiO2 (25 nm diameter) nanoparticles had only little influence. No effect of TiO2 nanoparticles on tryptophan breakdown was detected in unstimulated cells, whereas in stimulated cells, IDO activity and IFN-γ production were suppressed but only at the highest concentrations tested. Because neopterin was stimulated and tryptophan breakdown was suppressed in parallel, data suggests that the total effect of particles would be strongly pro-inflammatory. PMID:24361406

Modulating the activity of protein conjugated to gold nanoparticles by site-directed orientation and surface density of bound protein.

PubMed

Liu, Feng; Wang, Lei; Wang, Hongwei; Yuan, Lin; Li, Jingwen; Brash, John Law; Chen, Hong

2015-02-18

The key property of protein-nanoparticle conjugates is the bioactivity of the protein. The ability to accurately modulate the activity of protein on the nanoparticles at the interfaces is important in many applications. In the work reported here, modulation of the activity of protein-gold nanoparticle (AuNP) conjugates by specifically orienting the protein and by varying the surface density of the protein was investigated. Different orientations were achieved by introducing cysteine (Cys) residues at specific sites for binding to gold. We chose Escherichia coli inorganic pyrophosphatase (PPase) as a model protein and used site-directed mutagenesis to generate two mutant types (MTs) with a single Cys residue on the surface: MT1 with Cys near the active center and MT2 with Cys far from the active center. The relative activities of AuNP conjugates with wild type (WT), MT1, and MT2 were found to be 44.8%, 68.8%, and 91.2% of native PPase in aqueous solution. Site-directed orientation with the binding site far from the active center thus allowed almost complete preservation of the protein activity. The relative activity of WT and MT2 conjugates did not change with the surface density of the protein, while that of MT1 increased significantly with increasing surface density. These results demonstrate that site-directed orientation and surface density can both modulate the activity of proteins conjugated to AuNP and that orientation has a greater effect than density. Furthermore, increasing the surface density of the specifically oriented protein MT2, while having no significant effect on the specific activity of the protein, still allowed increased protein loading on the AuNP and thus increased the total protein activity. This is of great importance in the study on the interface of protein and nanoparticle and the applications for enzyme immobilization, drug delivery, and biocatalysis.

Development of SiC Nanoparticles and Second Phases Synergistically Reinforced Mg-Based Composites Processed by Multi-Pass Forging with Varying Temperatures

PubMed Central

Nie, Kaibo; Guo, Yachao; Deng, Kunkun; Wang, Xiaojun; Wu, Kun

2018-01-01

In this study, SiC nanoparticles were added into matrix alloy through a combination of semisolid stirring and ultrasonic vibration while dynamic precipitation of second phases was obtained through multi-pass forging with varying temperatures. During single-pass forging of the present composite, as the deformation temperature increased, the extent of recrystallization increased, and grains were refined due to the inhibition effect of the increasing amount of dispersed SiC nanoparticles. A small amount of twins within the SiC nanoparticle dense zone could be found while the precipitated phases of Mg17Al12 in long strips and deformation bands with high density dislocations were formed in the particle sparse zone after single-pass forging at 350 °C. This indicated that the particle sparse zone was mainly deformed by dislocation slip while the nanoparticle dense zone may have been deformed by twinning. The yield strength and ultimate tensile strength of the composites were gradually enhanced through increasing the single-pass forging temperature from 300 °C to 400 °C, which demonstrated that initial high forging temperature contributed to the improvement of the mechanical properties. During multi-pass forging with varying temperatures, the grain size of the composite was gradually decreased while the grain size distribution tended to be uniform with reducing the deformation temperature and extending the forging passes. In addition, the amount of precipitated second phases was significantly increased compared with that after multi-pass forging under a constant temperature. The improvement in the yield strength of the developed composite was related to grain refinement strengthening and Orowan strengthening resulting from synergistical effect of the externally applied SiC nanoparticles and internally precipitated second phases. PMID:29342883

Development of SiC Nanoparticles and Second Phases Synergistically Reinforced Mg-Based Composites Processed by Multi-Pass Forging with Varying Temperatures.

PubMed

Nie, Kaibo; Guo, Yachao; Deng, Kunkun; Wang, Xiaojun; Wu, Kun

2018-01-13

In this study, SiC nanoparticles were added into matrix alloy through a combination of semisolid stirring and ultrasonic vibration while dynamic precipitation of second phases was obtained through multi-pass forging with varying temperatures. During single-pass forging of the present composite, as the deformation temperature increased, the extent of recrystallization increased, and grains were refined due to the inhibition effect of the increasing amount of dispersed SiC nanoparticles. A small amount of twins within the SiC nanoparticle dense zone could be found while the precipitated phases of Mg 17 Al 12 in long strips and deformation bands with high density dislocations were formed in the particle sparse zone after single-pass forging at 350 °C. This indicated that the particle sparse zone was mainly deformed by dislocation slip while the nanoparticle dense zone may have been deformed by twinning. The yield strength and ultimate tensile strength of the composites were gradually enhanced through increasing the single-pass forging temperature from 300 °C to 400 °C, which demonstrated that initial high forging temperature contributed to the improvement of the mechanical properties. During multi-pass forging with varying temperatures, the grain size of the composite was gradually decreased while the grain size distribution tended to be uniform with reducing the deformation temperature and extending the forging passes. In addition, the amount of precipitated second phases was significantly increased compared with that after multi-pass forging under a constant temperature. The improvement in the yield strength of the developed composite was related to grain refinement strengthening and Orowan strengthening resulting from synergistical effect of the externally applied SiC nanoparticles and internally precipitated second phases.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Si; Nguyen-Phan, Thuy-Duong; Vovchok, Dimitriy

Successful introduction of gallium ions into TiO 2nanoparticles significantly promotes the H 2evolution activity and stability, increasing the opportunities for designing promising photocatalysts for green fuel production.

Hydrogen dissociation catalyzed by carbon-coated nickel nanoparticles: experiment and theory.

PubMed

Yermakov, Anatoliy Ye; Boukhvalov, Danil W; Uimin, Michael A; Lokteva, Ekaterina S; Erokhin, Alexey V; Schegoleva, Nina N

2013-02-04

Based on the combination of experimental measurements and first-principles calculations we report a novel carbon-based catalytic material and describe significant acceleration of the hydrogenation of magnesium at room temperature in the presence of nickel nanoparticles wrapped in multilayer graphene. The increase in rate of magnesium hydrogenation in contrast to a mix of graphite and nickel nanoparticles evidences intrinsic catalytic properties of the nanocomposites explored. The results from simulation demonstrate that doping of the metal substrate and the presence of Stone-Wales defects turn multilayer graphene from being chemically inert to chemically active. The role of the size of the nanoparticles and temperature are also discussed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Group A Streptococcal vaccine candidate: contribution of epitope to size, antigen presenting cell interaction and immunogenicity.

PubMed

Zaman, Mehfuz; Chandrudu, Saranya; Giddam, Ashwini K; Reiman, Jennifer; Skwarczynski, Mariusz; McPhun, Virginia; Moyle, Peter M; Batzloff, Michael R; Good, Michael F; Toth, Istvan

2014-12-01

Utilize lipopeptide vaccine delivery system to develop a vaccine candidate against Group A Streptococcus. Lipopeptides synthesized by solid-phase peptide synthesis-bearing carboxyl (C)-terminal and amino (N)-terminal Group A Streptococcus peptide epitopes. Nanoparticles formed were evaluated in vivo. Immune responses were induced in mice without additional adjuvant. We demonstrated for the first time that incorporation of the C-terminal epitope significantly enhanced the N-terminal epitope-specific antibody response and correlated with forming smaller nanoparticles. Antigen-presenting cells had increased uptake and maturation by smaller, more immunogenic nanoparticles. Antibodies raised by vaccination recognized isolates. Demonstrated the lipopeptidic nanoparticles to induce an immune response which can be influenced by the combined effect of epitope choice and size.

Phase controlled synthesis of (Mg, Ca, Ba)-ferrite magnetic nanoparticles with high uniformity

NASA Astrophysics Data System (ADS)

Wang, S. F.; Li, Q.; Zu, X. T.; Xiang, X.; Liu, W.; Li, S.

2016-12-01

(Mg, Ca, Ba)-ferrite magnetic nanoparticles were successfully synthesized through modifying the atomic ratio of polysaccharide and chelating agent at an optimal sintering temperature. In the process, the polysaccharide plays an important role in drastically shrinking the precursor during the gel drying process. In the metal-complex structure, M2+ ion active sites were coordinated by -OH of the water molecules except for EDTA anions. The MFe2O4 magnetic nanoparticles exhibited enhanced magnetic properties when compared with nano-MFe2O4 of similar particle size synthesized by other synthesis route reported in the literature. In particular, the sintering temperature improves the crystallinity and increases the hysteresis loop squareness ratio of (Mg, Ca, Ba)-ferrite nanoparticles significantly.

Zinc phthalocyanine-loaded PLGA biodegradable nanoparticles for photodynamic therapy in tumor-bearing mice.

PubMed

Fadel, Maha; Kassab, Kawser; Fadeel, Doa Abdel

2010-03-01

Nanoparticles formulated from the biodegradable copolymer poly(lactic-coglycolic acid) (PLGA) were investigated as a drug delivery system to enhance tissue uptake, permeation, and targeting of zinc(II) phthalocyanine (ZnPc) for photodynamic therapy. Three ZnPc nanoparticle formulations were prepared using a solvent emulsion evaporation method and the influence of sonication time on nanoparticle shape, encapsulation and size distribution, in vitro release, and in vivo photodynamic efficiency in tumor-bearing mice were studied. Sonication time did not affect the process yield or encapsulation efficiency, but did affect significantly the particle size. Sonication for 20 min reduced the mean particle size to 374.3 nm and the in vitro release studies demonstrated a controlled release profile of ZnPc. Tumor-bearing mice injected with ZnPc nanoparticles exhibited significantly smaller mean tumor volume, increased tumor growth delay and longer survival compared with the control group and the group injected with free ZnPc during the time course of the experiment. Histopathological examination of tumor from animals treated with PLGA ZnPc showed regression of tumor cells, in contrast to those obtained from animals treated with free ZnPc. The results indicate that ZnPc encapsulated in PLGA nanoparticles is a successful delivery system for improving photodynamic activity in the target tissue.

Microneedle-mediated transcutaneous immunization with plasmid DNA coated on cationic PLGA nanoparticles

PubMed Central

Kumar, Amit; Wonganan, Piyanuch; Sandoval, Michael A.; Li, Xinran; Zhu, Saijie; Cui, Zhengrong

2012-01-01

Previously, it was shown that microneedle-mediated transcutaneous immunization with plasmid DNA can potentially induce a stronger immune response than intramuscular injection of the same plasmid DNA. In the present study, we showed that the immune responses induced by transcutaneous immunization by applying plasmid DNA onto a skin area pretreated with solid microneedles were significantly enhanced by coating the plasmid DNA on the surface of cationic nanoparticles. In addition, the net surface charge of the DNA-coated nanoparticles significantly affected their in vitro skin permeation and their ability to induce immune responses in vivo. Transcutaneous immunization with plasmid DNA-coated net positively charged anoparticles elicited a stronger immune response than with plasmid DNA-coated net negatively charged nanoparticles or by intramuscular immunization with plasmid DNA alone. Transcutaneous immunization with plasmid DNA-coated net positively charged nanoparticles induced comparable immune responses as intramuscular injection of them, but transcutaneous immunization was able to induce specific mucosal immunity and a more balanced T helper type 1 and type 2 response. The ability of the net positively charged DNA-coated nanoparticles to induce a strong immune response through microneedle-mediated transcutaneous immunization may be attributed to their ability to increase the expression of the antigen gene encoded by the plasmid and to more effectively stimulate the maturation of antigen-presenting cells. PMID:22921518

Antibacterial Activity of Orthodontic Cement Containing Quaternary Ammonium Polyethylenimine Nanoparticles Adjacent to Orthodontic Brackets

PubMed Central

Sharon, Eldad; Sharabi, Revital; Eden, Adi; Zabrovsky, Asher; Ben-Gal, Gilad; Sharon, Esi; Houri-Haddad, Yael; Beyth, Nurit

2018-01-01

Enamel demineralization is a common problem found in patients using orthodontic devices, such as orthodontic braces. It was found that Streptoccocus mutans growth increases adjacent to orthodontic devices, which may result in caries development. Incorporated antibacterial quaternary ammonium polyethylenimine (QPEI) nanoparticles were previously shown to be highly efficacious against various bacteria. Combining antibacterial materials in orthodontic cement may be advantageous to prevent bacterial outgrowth adjacent to orthodontic brackets. The aim was to evaluate the efficiency of orthodontic cement containing QPEI nanoparticles in reducing S. mutans and Lactobacillus casei outgrowth adjacent to orthodontic brackets. Orthodontic brackets were bonded to the buccal surfaces of extracted lower incisors. The antibacterial effect on S. mutans and L. casei outgrowth of Neobond bracket adhesive orthodontic cement with and without QPEI nanoparticles was compared. The antibacterial effect was evaluated using crystal violet staining and bacterial count (CFU/mL). The teeth in the experimental group, with the QPEI nanoparticles cement, showed significantly lower optical density (OD) values and CFU counts of S. mutans and L. casei than the teeth in the control group (p < 0.05). Based on the results, it can be concluded that orthodontic cement containing QPEI nanoparticles significantly inhibits S. mutans and L. casei growth around orthodontic brackets. PMID:29584643

Antibacterial Activity of Orthodontic Cement Containing Quaternary Ammonium Polyethylenimine Nanoparticles Adjacent to Orthodontic Brackets.

PubMed

Sharon, Eldad; Sharabi, Revital; Eden, Adi; Zabrovsky, Asher; Ben-Gal, Gilad; Sharon, Esi; Pietrokovski, Yoav; Houri-Haddad, Yael; Beyth, Nurit

2018-03-27

Enamel demineralization is a common problem found in patients using orthodontic devices, such as orthodontic braces. It was found that Streptoccocus mutans growth increases adjacent to orthodontic devices, which may result in caries development. Incorporated antibacterial quaternary ammonium polyethylenimine (QPEI) nanoparticles were previously shown to be highly efficacious against various bacteria. Combining antibacterial materials in orthodontic cement may be advantageous to prevent bacterial outgrowth adjacent to orthodontic brackets. The aim was to evaluate the efficiency of orthodontic cement containing QPEI nanoparticles in reducing S. mutans and Lactobacillus casei outgrowth adjacent to orthodontic brackets. Orthodontic brackets were bonded to the buccal surfaces of extracted lower incisors. The antibacterial effect on S. mutans and L. casei outgrowth of Neobond bracket adhesive orthodontic cement with and without QPEI nanoparticles was compared. The antibacterial effect was evaluated using crystal violet staining and bacterial count (CFU/mL). The teeth in the experimental group, with the QPEI nanoparticles cement, showed significantly lower optical density (OD) values and CFU counts of S. mutans and L. casei than the teeth in the control group ( p < 0.05). Based on the results, it can be concluded that orthodontic cement containing QPEI nanoparticles significantly inhibits S. mutans and L. casei growth around orthodontic brackets.

Zirconium tungstate/epoxy nanocomposites: effect of nanoparticle morphology and negative thermal expansivity.

PubMed

Wu, Hongchao; Rogalski, Mark; Kessler, Michael R

2013-10-09

The ability to tailor the coefficient of thermal expansion (CTE) of a polymer is essential for mitigating thermal residual stress and reducing microcracks caused by CTE mismatch of different components in electronic applications. This work studies the effect of morphology and thermal expansivity of zirconium tungstate nanoparticles on the rheological, thermo-mechanical, dynamic-mechanical, and dielectric properties of ZrW2O8/epoxy nanocomposites. Three types of ZrW2O8 nanoparticles were synthesized under different hydrothermal conditions and their distinct properties were characterized, including morphology, particle size, aspect ratio, surface area, and CTE. Nanoparticles with a smaller particle size and larger surface area led to a more significant reduction in gel-time and glass transition temperature of the epoxy nanocomposites, while a higher initial viscosity and significant shear thinning behavior was found in prepolymer suspensions containing ZrW2O8 with larger particle sizes and aspect ratios. The thermo- and dynamic-mechanical properties of epoxy-based nanocomposites improved with increasing loadings of the three types of ZrW2O8 nanoparticles. In addition, the introduced ZrW2O8 nanoparticles did not negatively affect the dielectric constant or the breakdown strength of the epoxy resin, suggesting potential applications of ZrW2O8/epoxy nanocomposites in the microelectronic insulation industry.

Nanocomposite SAC Solders: The Effect of Adding Ni and Ni-Sn Nanoparticles on Morphology and Mechanical Properties of Sn-3.0Ag-0.5Cu Solders

NASA Astrophysics Data System (ADS)

Yakymovych, A.; Švec, P.; Orovcik, L.; Bajana, O.; Ipser, H.

2018-01-01

This study investigates the effect of minor additions of Ni, Ni3Sn or Ni3Sn2 nanoparticles on the microstructure and mechanical properties of Cu/solder/Cu joints. The nanocomposite Sn-3.0Ag-0.5Cu (SAC305) solders with 0.5, 1.0 and 2.0 wt.% metallic nanoparticles were prepared through a paste mixing method. The employed Ni and Ni-Sn nanoparticles were produced via a chemical reduction method. The microstructure of as-solidified Cu/solder/Cu joints was studied by x-ray diffraction and scanning electron microscopy. The results showed that additions of Ni and Ni-Sn nanoparticles to the SAC305 solder paste lead initially to a decrease in the average thickness of the intermetallic compound layer in the interface between solder and substrate, while further additions up to 2.0 wt.% did not induce any significant changes. In addition, shear strength and microhardness tests were performed to investigate the relationship between microstructure and mechanical properties of the investigated solder joints. The results indicated an increase in both of these properties which was most significant for the solder joints using SAC305 with 0.5 wt.% Ni or Ni-Sn nanoparticles.

Targeting nanoparticles to M cells with non-peptidic ligands for oral vaccination.

PubMed

Fievez, Virginie; Plapied, Laurence; des Rieux, Anne; Pourcelle, Vincent; Freichels, Hélène; Wascotte, Valentine; Vanderhaeghen, Marie-Lyse; Jerôme, Christine; Vanderplasschen, Alain; Marchand-Brynaert, Jacqueline; Schneider, Yves-Jacques; Préat, Véronique

2009-09-01

The presence of RGD on nanoparticles allows the targeting of beta1 integrins at the apical surface of human M cells and the enhancement of an immune response after oral immunization. To check the hypothesis that non-peptidic ligands targeting intestinal M cells or APCs would be more efficient for oral immunization than RGD, novel non-peptidic and peptidic analogs (RGD peptidomimitic (RGDp), LDV derivative (LDVd) and LDV peptidomimetic (LDVp)) as well as mannose were grafted on the PEG chain of PCL-PEG and incorporated in PLGA-based nanoparticles. RGD and RGDp significantly increased the transport of nanoparticles across an in vitro model of human M cells as compared to enterocytes. RGD, LDVp, LDVd and mannose enhanced nanoparticle uptake by macrophages in vitro. The intraduodenal immunization with RGDp-, LDVd- or mannose-labeled nanoparticles elicited a higher production of IgG antibodies than the intramuscular injection of free ovalbumin or intraduodenal administration of either non-targeted or RGD-nanoparticles. Targeted formulations were also able to induce a cellular immune response. In conclusion, the in vitro transport of nanoparticles, uptake by macrophages and the immune response were positively influenced by the presence of ligands at the surface of nanoparticles. These targeted-nanoparticles could thus represent a promising delivery system for oral immunization.

Preparation and characterization of the Adriamycin-loaded amphiphilic chitosan nanoparticles and their application in the treatment of liver cancer

PubMed Central

Kou, Chang-Hua; Han, Jin; Han, Xi-Lin; Zhuang, Hui-Jie; Zhao, Zi-Ming

2017-01-01

In the present study, two nanoparticles including lactose myristoyl carboxymethyl chitosan (LMCC) and algal polysaccharide myristoyl carboxymethyl chitosan (AMCC), were obtained for hepatic-targeted Adriamycin (ADM) drug delivery systems. ADM was successfully loaded into the LMCC or AMCC nanoparticle by dialysis. The release function and liver targeting of the nanoparticles was explored, and it was revealed that ADM release from the nanoparticles was greatest at acidic pH 5.5. ADM-conjugated nanoparticles were readily taken up by HU7 human hepatocellular carcinoma cells, relative to HT22 mouse hippocampal neuron cells in vitro. In vivo, ADM-loaded nanoparticles had significant antitumor efficacy with a 62.7% inhibition rate, followed by ADM and ADM-AMCC (51.2 and 42.5%, respectively). The tissue distribution study confirmed that ADM-LMCC had an improved liver delivery efficacy, by comparison with ADM. Furthermore, a series of safety studies, including hemolysis, acute toxicity and organ toxicity, revealed that the ADM-loaded LMCC and AMCC nanoparticles had advantages over the commercially available injectable preparation of Adriamycin hydrochloride, in terms of low toxicity levels and increased tolerated dose. These results indicated that LMCC is a promising carrier for injectable ADM nanoparticle and ADM-conjugated nanoparticles may improve the efficacy of ADM by hepatic targeting. PMID:29344229

Side chain variations radically alter the diffusion of poly(2-alkyl-2-oxazoline) functionalised nanoparticles through a mucosal barrier.

PubMed

Mansfield, Edward D H; de la Rosa, Victor R; Kowalczyk, Radoslaw M; Grillo, Isabelle; Hoogenboom, Richard; Sillence, Katy; Hole, Patrick; Williams, Adrian C; Khutoryanskiy, Vitaliy V

2016-08-16

Functionalised nanomaterials are gaining popularity for use as drug delivery vehicles and, in particular, mucus penetrating nanoparticles may improve drug bioavailability via the oral route. To date, few polymers have been investigated for their muco-penetration, and the effects of systematic structural changes to polymer architectures on the penetration and diffusion of functionalised nanomaterials through mucosal tissue have not been reported. We investigated the influence of poly(2-oxazoline) alkyl side chain length on nanoparticle diffusion; poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), and poly(2-n-propyl-2-oxazoline) were grafted onto the surface of thiolated silica nanoparticles and characterised by FT-IR, Raman and NMR spectroscopy, thermogravimetric analysis, and small angle neutron scattering. Diffusion coefficients were determined in water and in a mucin dispersion (using Nanoparticle Tracking Analysis), and penetration through a mucosal barrier was assessed using an ex vivo fluorescence technique. The addition of a single methylene group in the side chain significantly altered the penetration and diffusion of the materials in both mucin dispersions and mucosal tissue. Nanoparticles functionalised with poly(2-methyl-2-oxazoline) were significantly more diffusive than particles with poly(2-ethyl-2-oxazoline) while particles with poly(2-n-propyl-2-oxazoline) showed no significant increase compared to the unfunctionalised particles. These data show that variations in the polymer structure can radically alter their diffusive properties with clear implications for the future design of mucus penetrating systems.

Selective killing of hepatocellular carcinoma HepG2 cells by three-dimensional nanographene nanoparticles based on triptycene

NASA Astrophysics Data System (ADS)

Xiong, Xiaoqin; Gan, Lu; Liu, Ying; Zhang, Chun; Yong, Tuying; Wang, Ziyi; Xu, Huibi; Yang, Xiangliang

2015-03-01

Carbon-based materials have been widely used in the biomedical fields including drug delivery and cancer therapies. In this paper, a recently synthesized three-dimensional nanographene (NG) based on triptycene self-assembles into nanoparticles which selectively kill human hepatocellular carcinoma HepG2 cells as compared to human normal liver HL7702 cells. Obvious differences in cellular accumulation, the endocytic pathway and intracellular trafficking of NG nanoparticles are observed in HepG2 cells and HL7702 cells. Further studies reveal that NG nanoparticles significantly increase the levels of reactive oxygen species (ROS) in HepG2 cells, but not in HL7702 cells. NG nanoparticle-induced ROS result in apoptosis induction and the decrease in mitochondrial membrane potential in HepG2 cells. Moreover, IKK/nuclear factor-κB (NF-κB) signaling is found to be activated by NG nanoparticle-induced ROS and serves to antagonize NG nanoparticle-induced apoptosis in HepG2 cells. Our studies show that the distinct behaviors of cellular uptake and ROS-mediated cytotoxicity are responsible for the selective killing of HepG2 cells. This study provides a foundation for understanding the mechanism of selective induction of apoptosis in cancer cells by NG nanoparticles and designing more effective chemotherapeutical agents.Carbon-based materials have been widely used in the biomedical fields including drug delivery and cancer therapies. In this paper, a recently synthesized three-dimensional nanographene (NG) based on triptycene self-assembles into nanoparticles which selectively kill human hepatocellular carcinoma HepG2 cells as compared to human normal liver HL7702 cells. Obvious differences in cellular accumulation, the endocytic pathway and intracellular trafficking of NG nanoparticles are observed in HepG2 cells and HL7702 cells. Further studies reveal that NG nanoparticles significantly increase the levels of reactive oxygen species (ROS) in HepG2 cells, but not in HL7702 cells. NG nanoparticle-induced ROS result in apoptosis induction and the decrease in mitochondrial membrane potential in HepG2 cells. Moreover, IKK/nuclear factor-κB (NF-κB) signaling is found to be activated by NG nanoparticle-induced ROS and serves to antagonize NG nanoparticle-induced apoptosis in HepG2 cells. Our studies show that the distinct behaviors of cellular uptake and ROS-mediated cytotoxicity are responsible for the selective killing of HepG2 cells. This study provides a foundation for understanding the mechanism of selective induction of apoptosis in cancer cells by NG nanoparticles and designing more effective chemotherapeutical agents. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07248k

Solid-liquid and liquid-solid transitions in metal nanoparticles.

PubMed

Hou, M

2017-02-22

The melting and solidification temperatures of nanosystems may differ by several hundred Kelvin. To understand the origin of this difference, transitions in small metallic nanoparticles on the atomic scale were analyzed using molecular dynamics (MD). Palladium was used as a case study, which was then extended to a range of other elemental metals. It was argued that in realistic environments, such as gases at low pressure (of the order of 1 mbar), heat transfers allow the microcanonical thermal equilibrium evolution of the nanoparticles between successive collisions with gas atoms. This is shown to have no significant influence on the mechanism of melting, whereas in an isolated nanoparticle, solidification triggers a huge and rapid increase in temperature. A simple relationship between the melting and solidification temperatures was found, indicating that the magnitude of the latent heat of melting governs undercooling. Whereas melting occurs via heterogeneous nucleation, solidification displays characteristics of spinodal decomposition. Consistently, the melting temperature scales with the surface-to-volume ratio, whereas the solidification temperature displays no significant dependence on the particle size.

Potential for enhancing external beam radiotherapy for lung cancer using high-Z nanoparticles administered via inhalation

NASA Astrophysics Data System (ADS)

Hao, Yao; Altundal, Yucel; Moreau, Michele; Sajo, Erno; Kumar, Rajiv; Ngwa, Wilfred

2015-09-01

Nanoparticle-aided radiation therapy is emerging as a promising modality to enhance radiotherapy via the radiosensitizing action of high atomic number (Z) nanoparticles. However, the delivery of sufficiently potent concentrations of such nanoparticles to the tumor remain a challenge. This study investigates the dose enhancement to lung tumors due to high-Z nanoparticles (NPs) administered via inhalation during external beam radiotherapy. Here NPs investigated include: cisplatin nanoparticles (CNPs), carboplatin nanoparticles (CBNPs), and gold nanoparticles (GNPs). Using Monte Carlo-generated megavoltage energy spectra, a previously employed analytic method was used to estimate dose enhancement to lung tumors due to radiation-induced photoelectrons from the NPs administered via inhalation route (IR) in comparison to intravenous (IV) administration. Previous studies have indicated about 5% of FDA-approved cisplatin concentrations reach the lung via IV. Meanwhile recent experimental studies indicate that 3.5-14.6 times higher concentrations of NPs can reach the lung by IR compared to IV. Taking these into account, the dose enhancement factor (DEF) defined as the ratio of the radiotherapy dose with and without nanoparticles was calculated for a range of NPs concentrations and tumor sizes. The DEF for IR was then compared with that for IV. For IR with 3.5 times higher concentrations than IV, and 2 cm diameter tumor, clinically significant DEF values of up to 1.19, 1.26, and 1.51 were obtained for CNPs, CBNPs and GNPs. In comparison values of 1.06, 1.08, and 1.15 were obtained via IV administration. For IR with 14.6 times higher concentrations, even higher DEF values were obtained e.g. 1.81 for CNPs. Results also showed that the DEF increased with increasing field size or decreasing tumor volume, as expected. The results of this work indicate that IR administration of targeted high-Z CNPs/CBNPs/GNPs could enable clinically significant DEF to lung tumors compared to IV administration during external beam radiotherapy. For FDA approved concentrations of CNPs or CBNPs considered, this could allow for additional dose enhancement to tumors via photoelectric mechanism during concomitant chemoradiotherapy.

Fabrication, nanomechanical characterization, and cytocompatibility of gold-reinforced chitosan bio-nanocomposites

PubMed Central

Patel, Nimitt G.; Kumar, Ajeet; Jayawardana, Veroni N.; Woodworth, Craig D.; Yuya, Philip A.

2017-01-01

Chitosan, a naturally derived polymer represents one of the most technologically important classes of active materials with applications in a variety of industrial and biomedical fields. Gold nanoparticles (~32 nm) were synthesized via a citrate reduction method from chloroauric acid and incorporated in Chitosan matrix. Bio-nanocomposite films with varying concentrations of gold nanoparticles were prepared through solution casting process. Uniform distribution of gold nanoparticles was achieved throughout the chitosan matrix and was confirmed with SEM. Synthesis outcomes and prepared nanocomposites were characterized using SEM, TEM, EDX, SAED, UV–vis, XRD, DLS, and Zeta potential for their physical, morphological and structural properties. Nanoscale properties of materials under the influence of temperature were characterized through nanoindentation techniques. From quasi-static nanoindentation, it was observed that hardness and reduced modulus of the nanocomposites were increased significantly in direct proportion to the gold nanoparticle concentration. Gold nanoparticle concentration also showed positive impact on storagemodulus and thermal stability of the material. The obtained films were confirmed to be biocompatible by their ability to support growth of human cells in vitro. In summary, the results show enhanced mechanical properties with increasing gold nanoparticle concentration, and provide better understanding of the structure–property relationships of such biocompatiblematerials for potential biomedical applications. PMID:25280713

Experimental Study on Influence of Trap Parameters on Dielectric Characteristics of Nano-Modified Insulation Pressboard

PubMed Central

Chen, Qingguo; Liu, Heqian; Chi, Minghe; Wang, Yonghong; Wei, Xinlao

2017-01-01

In order to study the influence of trap parameters on dielectric characteristics of nano-modified pressboards, pressboards were made using the nano doping method with different nanoparticle components. The dielectric characteristics of the modified pressboards were measured, and the trap parameters were investigated using the thermally stimulated current (TSC) method. The test results indicated that the conductivity initially declined and then rose with the increase of nano-Al2O3 content, whereas it solely rose with the increase of nano-SiC content. Moreover, the conductivity exhibited nonlinear characteristics with the enhancement of electric field stress at high nanoparticle content. The relative permittivity of modified pressboard declines initially and then rises with the increase of nanoparticle content. In addition, the breakdown strength of modified pressboards exhibited a pattern of incline followed by decline with the increase of nano-Al2O3 content, while it always declined with the increase of nano-SiC content. The analysis based on the energy band theory on trap parameters of the constructed multi-core model concludes that the nanoparticle components added in pressboard altered both the depth and density of traps. It is therefore concluded that trap parameters have significant influence on the dielectric characteristics of nano-modified insulation pressboard. PMID:28772448

Experimental Study on Influence of Trap Parameters on Dielectric Characteristics of Nano-Modified Insulation Pressboard.

PubMed

Chen, Qingguo; Liu, Heqian; Chi, Minghe; Wang, Yonghong; Wei, Xinlao

2017-01-22

In order to study the influence of trap parameters on dielectric characteristics of nano-modified pressboards, pressboards were made using the nano doping method with different nanoparticle components. The dielectric characteristics of the modified pressboards were measured, and the trap parameters were investigated using the thermally stimulated current (TSC) method. The test results indicated that the conductivity initially declined and then rose with the increase of nano-Al₂O₃ content, whereas it solely rose with the increase of nano-SiC content. Moreover, the conductivity exhibited nonlinear characteristics with the enhancement of electric field stress at high nanoparticle content. The relative permittivity of modified pressboard declines initially and then rises with the increase of nanoparticle content. In addition, the breakdown strength of modified pressboards exhibited a pattern of incline followed by decline with the increase of nano-Al₂O₃ content, while it always declined with the increase of nano-SiC content. The analysis based on the energy band theory on trap parameters of the constructed multi-core model concludes that the nanoparticle components added in pressboard altered both the depth and density of traps. It is therefore concluded that trap parameters have significant influence on the dielectric characteristics of nano-modified insulation pressboard.

The Interaction between Zein and Lecithin in Ethanol-Water Solution and Characterization of Zein-Lecithin Composite Colloidal Nanoparticles.

PubMed

Dai, Lei; Sun, Cuixia; Wang, Di; Gao, Yanxiang

2016-01-01

Lecithin, a naturally small molecular surfactant, which is widely used in the food industry, can delay aging, enhance memory, prevent and treat diabetes. The interaction between zein and soy lecithin with different mass ratios (20:1, 10:1, 5:1, 3:1, 2:1, 1:1 and 1:2) in ethanol-water solution and characterisation of zein and lecithin composite colloidal nanoparticles prepared by antisolvent co-precipitation method were investigated. The mean size of zein-lecithin composite colloidal nanoparticles was firstly increased with the rise of lecithin concentration and then siginificantly decreased. The nanoparticles at the zein to lecithin mass ratio of 5:1 had the largest particle size (263 nm), indicating that zein and lecithin formed composite colloidal nanoparticles, which might aggregate due to the enhanced interaction at a higher proportion of lecithin. Continuing to increase lecithin concentration, the zein-lecithin nanoparticles possibly formed a reverse micelle-like or a vesicle-like structure with zein in the core, which prevented the formation of nanoparticle aggregates and decreased the size of composite nanoparticles. The presence of lecithin significantly reduced the ζ-potential of zein-lecithin composite colloidal nanoparticles. The interaction between zein and lecithin enhanced the intensity of the fluorescence emission of zein in ethanol-water solution. The secondary structure of zein was also changed by the addition of lecithin. Differential scanning calorimetry thermograms revealed that the thermal stability of zein-lecithin nanoparticles was enhanced with the rise of lecithin level. The composite nanoparticles were relatively stable to elevated ionic strengths. Possible interaction mechanism between zein and lecithin was proposed. These findings would help further understand the theory of the interaction between the alcohol soluble protein and the natural small molecular surfactant. The composite colloidal nanoparticles formed in this study can broaden the application of zein and be suitable for incorporating water-insoluble bioactive components in functional food and beverage products.

Enhanced stability of Janus nanoparticles by covalent cross-linking of surface ligands.

PubMed

Song, Yang; Klivansky, Liana M; Liu, Yi; Chen, Shaowei

2011-12-06

A mercapto derivative of diacetylene was used as the hydrophilic ligand to prepare Janus nanoparticles by using hydrophobic hexanethiolate-protected gold (AuC6, diameter 5 nm) nanoparticles as the starting materials. The amphiphilic surface characters of the Janus nanoparticles were verified by contact angle measurements, as compared to those of the bulk-exchange counterparts where the two types of ligands were distributed rather homogeneously on the nanoparticle surface. Dynamic light scattering studies showed that the Janus nanoparticles formed stable superstructures in various solvent media that were significantly larger than those by the bulk-exchange counterparts. This was ascribed to the amphiphilic characters of the Janus nanoparticles that rendered the particles to behave analogously to conventional surfactant molecules. Notably, because of the close proximity of the diacetylene moieties on the Janus nanoparticle surface, exposure to UV irradiation led to effective covalent cross-linking between the diacetylene moieties of neighboring ligands, as manifested in UV-vis and fluorescence measurements where the emission characteristics of dimers and trimers of diacetylene were rather well-defined, in addition to the monomeric emission. In contrast, for bulk-exchange nanoparticles, no trimer emission could be identified, and the intensity of dimer emission was markedly lower (though the intensity increased with increasing diacetylene coverage on the particle surface) under the otherwise identical experimental conditions. This is largely because the diacetylene ligands were distributed on the entire particle surface, and it was difficult to find a large number of ligands situated closely so that the stringent topochemical principles for the polymerization of diacetylene derivatives could be met. Importantly, the cross-linked Janus nanoparticles were found to exhibit marked enhancement of the structural integrity, which was attributable to the impeded surface diffusion of the thiol ligands on the nanoparticle surface, as manifested in fluorescence measurements of aged nanoparticles. © 2011 American Chemical Society

The Interaction between Zein and Lecithin in Ethanol-Water Solution and Characterization of Zein–Lecithin Composite Colloidal Nanoparticles

PubMed Central

Dai, Lei; Sun, Cuixia; Wang, Di; Gao, Yanxiang

2016-01-01

Lecithin, a naturally small molecular surfactant, which is widely used in the food industry, can delay aging, enhance memory, prevent and treat diabetes. The interaction between zein and soy lecithin with different mass ratios (20:1, 10:1, 5:1, 3:1, 2:1, 1:1 and 1:2) in ethanol-water solution and characterisation of zein and lecithin composite colloidal nanoparticles prepared by antisolvent co-precipitation method were investigated. The mean size of zein-lecithin composite colloidal nanoparticles was firstly increased with the rise of lecithin concentration and then siginificantly decreased. The nanoparticles at the zein to lecithin mass ratio of 5:1 had the largest particle size (263 nm), indicating that zein and lecithin formed composite colloidal nanoparticles, which might aggregate due to the enhanced interaction at a higher proportion of lecithin. Continuing to increase lecithin concentration, the zein-lecithin nanoparticles possibly formed a reverse micelle-like or a vesicle-like structure with zein in the core, which prevented the formation of nanoparticle aggregates and decreased the size of composite nanoparticles. The presence of lecithin significantly reduced the ζ-potential of zein-lecithin composite colloidal nanoparticles. The interaction between zein and lecithin enhanced the intensity of the fluorescence emission of zein in ethanol-water solution. The secondary structure of zein was also changed by the addition of lecithin. Differential scanning calorimetry thermograms revealed that the thermal stability of zein-lecithin nanoparticles was enhanced with the rise of lecithin level. The composite nanoparticles were relatively stable to elevated ionic strengths. Possible interaction mechanism between zein and lecithin was proposed. These findings would help further understand the theory of the interaction between the alcohol soluble protein and the natural small molecular surfactant. The composite colloidal nanoparticles formed in this study can broaden the application of zein and be suitable for incorporating water-insoluble bioactive components in functional food and beverage products. PMID:27893802

Applications of nanotechnology in dermatology.

PubMed

DeLouise, Lisa A

2012-03-01

What are nanoparticles and why are they important in dermatology? These questions are addressed by highlighting recent developments in the nanotechnology field that have increased the potential for intentional and unintentional nanoparticle skin exposure. The role of environmental factors in the interaction of nanoparticles with skin and the potential mechanisms by which nanoparticles may influence skin response to environmental factors are discussed. Trends emerging from recent literature suggest that the positive benefit of engineered nanoparticles for use in cosmetics and as tools for understanding skin biology and curing skin disease outweigh potential toxicity concerns. Discoveries reported in this journal are highlighted. This review begins with a general introduction to the field of nanotechnology and nanomedicine. This is followed by a discussion of the current state of understanding of nanoparticle skin penetration and their use in three therapeutic applications. Challenges that must be overcome to derive clinical benefit from the application of nanotechnology to skin are discussed last, providing perspective on the significant opportunity that exists for future studies in investigative dermatology.

Zerovalent bismuth nanoparticles inhibit Streptococcus mutans growth and formation of biofilm

PubMed Central

Hernandez-Delgadillo, Rene; Velasco-Arias, Donaji; Diaz, David; Arevalo-Niño, Katiushka; Garza-Enriquez, Marianela; De la Garza-Ramos, Myriam A; Cabral-Romero, Claudio

2012-01-01

Background and methods Despite continuous efforts, the increasing prevalence of resistance among pathogenic bacteria to common antibiotics has become one of the most significant concerns in modern medicine. Nanostructured materials are used in many fields, including biological sciences and medicine. While some bismuth derivatives has been used in medicine to treat vomiting, nausea, diarrhea, and stomach pain, the biocidal activity of zerovalent bismuth nanoparticles has not yet been studied. The objective of this investigation was to analyze the antimicrobial activity of bismuth nanoparticles against oral bacteria and their antibiofilm capabilities. Results Our results showed that stable colloidal bismuth nanoparticles had 69% antimicrobial activity against Streptococcus mutans growth and achieved complete inhibition of biofilm formation. These results are similar to those obtained with chlorhexidine, the most commonly used oral antiseptic agent. The minimal inhibitory concentration of bismuth nanoparticles that interfered with S. mutans growth was 0.5 mM. Conclusion These results suggest that zerovalent bismuth nanoparticles could be an interesting antimicrobial agent to be incorporated into an oral antiseptic preparation. PMID:22619547

Cryoprotectant choice and analyses of freeze-drying drug suspension of nanoparticles with functional stabilisers.

PubMed

Wang, Lulu; Ma, Yingying; Gu, Yu; Liu, Yangyang; Zhao, Juan; Yan, Beibei; Wang, Yancai

2018-04-19

Freeze-drying is an effective way to improve long-term physical stability of nanosuspension in drug delivery applications. Nanosuspension also known as suspension of nanoparticles. In this study, the effect of freeze-drying with different cryoprotectants on the physicochemical characteristics of resveratrol (RSV) nanosuspension and quercetin (QUE) nanosuspension was evaluated. D-α-tocopheryl polyethylene glycol succinate (TPGS) and folate-modified distearoylphosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG-FA) were selected as functional stabilisers formulated nanosuspension which were prepared by anti-solvent precipitation method. RSV nanoparticle size and QUE nanoparticle size were about 210 and 110 nm, respectively. The AFM and TEM results of nanosuspension showed uniform and irregular shape particles. After freeze-drying, the optimal concentration of four cryoprotectants was determined by the particle size of re-dispersed nanoparticles. The dissolution profile of drug nanoparticle significantly showed approximately at a 6-8-fold increase dissolution rate. Moreover, TPGS and DSPE-PEG-FA stabilised RSV nanosuspension and QUE nanosuspension samples showed better effect on long-term physical stability.

Thrombolysis based on magnetically-controlled surface-functionalized Fe3O4 nanoparticle

PubMed Central

Chang, Ming; Lin, Yu-Hao; Gabayno, Jacque Lynn; Li, Qian; Liu, Xiaojun

2017-01-01

ABSTRACT In this study, the control of magnetic fields to manipulate surface-functionalized Fe3O4 nanoparticles by urokinase coating is investigated for thrombolysis in a microfluidic channel. The urokinase-coated Fe3O4 nanoparticles are characterized using particle size distribution, zeta potential measurement and spectroscopic data. Thrombolytic ratio tests reveal that the efficiency for thrombus cleaning is significantly improved when using magnetically-controlled urokinase-coated Fe3O4 nanoparticles than pure urokinase solution. The average increase in the rate of thrombolysis with the use of urokinase-coated Fe3O4 nanoparticles is about 50%. In vitro thrombolysis test in a microfluidic channel using the coated nanoparticles shows nearly complete removal of thrombus, a result that can be attributed to the clot busting effect of the urokinase as it inhibits the possible formation of blood bolus during the magnetically-activated microablation process. The experiment further demonstrates that a thrombus mass of 10.32 mg in the microchannel is fully removed in about 180 s. PMID:27689864

The improvement of characteristics of biodegradable films made from kefiran-whey protein by nanoparticle incorporation.

PubMed

Zolfi, Mohsen; Khodaiyan, Faramarz; Mousavi, Mohammad; Hashemi, Maryam

2014-08-30

Biodegradable kefiran-whey protein isolate (WPI) nanocomposites were produced using montmorillonite (MMT) and nano-TiO2 as nanoparticles in the percentage of 1, 3, and 5% (w/w) by a casting and solvent-evaporation method. Physical, mechanical, and water-vapor permeability (WVP) properties were determined as a function of nanoparticle concentration. The results revealed that the effect of these nanoparticles was different according to their nature and percentage. The films incorporated with 5% (w/w) MMT showed the highest tensile strength, Young's modulus, puncture strength, and the lowest WVP compared with the control and TiO2 added films. In contrast to MMT, addition of TiO2 nanoparticles due to the plasticizing effect led to a significant change in color and transparency of nanocomposite. Scanning electron microscopy (SEM) observations demonstrated the films' properties in relation to their microstructures. The surface topography results also showed a considerable increase in roughness parameters by incorporating the nanoparticles in kefiran-WPI matrix. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison and functionalization study of microemulsion-prepared magnetic iron oxide nanoparticles.

PubMed

Okoli, Chuka; Sanchez-Dominguez, Margarita; Boutonnet, Magali; Järås, Sven; Civera, Concepción; Solans, Conxita; Kuttuva, Gunaratna Rajarao

2012-06-05

Magnetic iron oxide nanoparticles (MION) for protein binding and separation were obtained from water-in-oil (w/o) and oil-in-water (o/w) microemulsions. Characterization of the prepared nanoparticles have been performed by TEM, XRD, SQUID magnetometry, and BET. Microemulsion-prepared magnetic iron oxide nanoparticles (ME-MION) with sizes ranging from 2 to 10 nm were obtained. Study on the magnetic properties at 300 K shows a large increase of the magnetization ~35 emu/g for w/o-ME-MION with superparamagnetic behavior and nanoscale dimensions in comparison with o/w-ME-MION (10 emu/g) due to larger particle size and anisotropic property. Moringa oleifera coagulation protein (MOCP) bound w/o- and o/w-ME-MION showed an enhanced performance in terms of coagulation activity. A significant interaction between the magnetic nanoparticles and the protein can be described by changes in fluorescence emission spectra. Adsorbed protein from MOCP is still retaining its functionality even after binding to the nanoparticles, thus implying the extension of this technique for various applications.

Preliminary study of injury from heating systemically delivered, nontargeted dextran–superparamagnetic iron oxide nanoparticles in mice

PubMed Central

Kut, Carmen; Zhang, Yonggang; Hedayati, Mohammad; Zhou, Haoming; Cornejo, Christine; Bordelon, David; Mihalic, Jana; Wabler, Michele; Burghardt, Elizabeth; Gruettner, Cordula; Geyh, Alison; Brayton, Cory; Deweese, Theodore L; Ivkov, Robert

2013-01-01

Aim To assess the potential for injury to normal tissues in mice due to heating systemically delivered magnetic nanoparticles in an alternating magnetic field (AMF). Materials & methods Twenty three male nude mice received intravenous injections of dextran–superparamagnetic iron oxide nanoparticles on days 1–3. On day 6, they were exposed to AMF. On day 7, blood, liver and spleen were harvested and analyzed. Results Iron deposits were detected in the liver and spleen. Mice that had received a high-particle dose and a high AMF experienced increased mortality, elevated liver enzymes and significant liver and spleen necrosis. Mice treated with low-dose superparamagnetic iron oxide nanoparticles and a low AMF survived, but had elevated enzyme levels and local necrosis in the spleen. Conclusion Magnetic nanoparticles producing only modest heat output can cause damage, and even death, when sequestered in sufficient concentrations. Dextran–superparamagnetic iron oxide nanoparticles are deposited in the liver and spleen, making these the sites of potential toxicity. PMID:22830502

Silver and palladium alloy nanoparticle catalysts: reductive coupling of nitrobenzene through light irradiation.

PubMed

Peiris, Sunari; Sarina, Sarina; Han, Chenhui; Xiao, Qi; Zhu, Huai-Yong

2017-08-15

Silver-palladium (Ag-Pd) alloy nanoparticles strongly absorb visible light and exhibit significantly higher photocatalytic activity compared to both pure palladium (Pd) and silver (Ag) nanoparticles. Photocatalysts of Ag-Pd alloy nanoparticles on ZrO 2 and Al 2 O 3 supports are developed to catalyze the nitroaromatic coupling to the corresponding azo compounds under visible light irradiation. Ag-Pd alloy NP/ZrO 2 exhibited the highest photocatalytic activity for nitrobenzene coupling to azobenzene (yield of ∼80% in 3 hours). The photocatalytic efficiency could be optimized by altering the Ag : Pd ratio of the alloy nanoparticles, irradiation light intensity, temperature and wavelength. The rate of the reaction depends on the population and energy of the excited electrons, which can be improved by increasing the light intensity or by using a shorter wavelength. The knowledge developed in this study may inspire further studies on Ag alloy photocatalysts and organic syntheses using Ag-Pd nanoparticle catalysts driven under visible light Irradiation.

Applications of Nanotechnology in Dermatology

PubMed Central

DeLouise, Lisa A.

2014-01-01

What are nanoparticles and why are they important in dermatology? These questions are addressed by highlighting recent developments in the nanotechnology field that have increased the potential for intentional and unintended nanoparticle skin exposure. The role of environmental factors in the interaction of nanoparticles with skin and the potential mechanisms by which nanoparticles may influence skin response to environmental factors are discussed. Trends emerging from recent literature suggest that the positive benefit of engineered nanoparticles for use in cosmetics and as tools for understanding skin biology and curing skin disease, out weigh potential toxicity concerns. Discoveries reported in this journal are highlighted. This review begins with a general introduction to the field of nanotechnology and nanomedicine. This is followed by a discussion of the current state of understanding of nanoparticle skin penetration and their use in three different therapeutic applications. Challenges that must be overcome to derive clinical benefit from the application of nanotechnology to skin are discussed last, providing perspective on the significant opportunity that exists for future studies in investigative dermatology. PMID:22217738

Experimental Investigation of Mechanical and Thermal Properties of Silica Nanoparticle-Reinforced Poly(acrylamide) Nanocomposite Hydrogels

PubMed Central

O’Brien, Victor; Chang, Andrew; Blanco, Matthew; Zabalegui, Aitor; Lee, Hohyun; Asuri, Prashanth

2015-01-01

Current studies investigating properties of nanoparticle-reinforced polymers have shown that nanocomposites often exhibit improved properties compared to neat polymers. However, over two decades of research, using both experimental studies and modeling analyses, has not fully elucidated the mechanistic underpinnings behind these enhancements. Moreover, few studies have focused on developing an understanding among two or more polymer properties affected by incorporation of nanomaterials. In our study, we investigated the elastic and thermal properties of poly(acrylamide) hydrogels containing silica nanoparticles. Both nanoparticle concentration and size affected hydrogel properties, with similar trends in enhancements observed for elastic modulus and thermal diffusivity. We also observed significantly lower swellability for hydrogel nanocomposites relative to neat hydrogels, consistent with previous work suggesting that nanoparticles can mediate pseudo crosslinking within polymer networks. Collectively, these results indicate the ability to develop next-generation composite materials with enhanced mechanical and thermal properties by increasing the average crosslinking density using nanoparticles. PMID:26301505

In situ synthesis of silver-nanoparticles/bacterial cellulose composites for slow-released antimicrobial wound dressing.

PubMed

Wu, Jian; Zheng, Yudong; Song, Wenhui; Luan, Jiabin; Wen, Xiaoxiao; Wu, Zhigu; Chen, Xiaohua; Wang, Qi; Guo, Shaolin

2014-02-15

Bacterial cellulose has attracted increasing attention as a novel wound dressing material, but it has no antimicrobial activity, which is one of critical skin-barrier functions in wound healing. To overcome such deficiency, we developed a novel method to synthesize and impregnate silver nanoparticles on to bacterial cellulose nanofibres (AgNP-BC). Uniform spherical silver nano-particles (10-30 nm) were generated and self-assembled on the surface of BC nano-fibers, forming a stable and evenly distributed Ag nanoparticles coated BC nanofiber. Such hybrid nanostructure prevented Ag nanoparticles from dropping off BC network and thus minimized the toxicity of nanoparticles. Regardless the slow Ag(+) release, AgNP-BC still exhibited significant antibacterial activities with more than 99% reductions in Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, AgNP-BC allowed attachment and growth of epidermal cells with no cytotoxicity emerged. The results demonstrated that AgNP-BC could reduce inflammation and promote wound healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preparation and Physicochemical Properties of 10-Hydroxycamptothecin (HCPT) Nanoparticles by Supercritical Antisolvent (SAS) Process

PubMed Central

Zhao, Xiuhua; Zu, Yuangang; Jiang, Ru; Wang, Ying; Li, Yong; Li, Qingyong; Zhao, Dongmei; Zu, Baishi; Zhang, Baoyou; Sun, Zhiqiang; Zhang, Xiaonan

2011-01-01

The goal of the present work was to study the feasibility of 10-hydroxycamptothecin (HCPT) nanoparticle preparation using supercritical antisolvent (SAS) precipitation. The influences of various experimental factors on the mean particle size (MPS) of HCPT nanoparticles were investigated. The optimum micronization conditions are determined as follows: HCPT solution concentration 0.5 mg/mL, the flow rate ratio of CO2 and HCPT solution 19.55, precipitation temperature 35 °C and precipitation pressure 20 MPa. Under the optimum conditions, HCPT nanoparticles with a MPS of 180 ± 20.3 nm were obtained. Moreover, the HCPT nanoparticles obtained were characterized by Scanning electron microscopy, Dynamic light scattering, Fourier-transform infrared spectroscopy, High performance liquid chromatography-mass spectrometry, X-ray diffraction and Differential scanning calorimetry analyses. The physicochemical characterization results showed that the SAS process had not induced degradation of HCPT. Finally, the dissolution rates of HCPT nanoparticles were investigated and the results proved that there is a significant increase in dissolution rate compared to unprocessed HCPT. PMID:21731466

Kenaf Bast Fibers—Part II: Inorganic Nanoparticle Impregnation for Polymer Composites

DOE PAGES

Shi, Jinshu; Shi, Sheldon Q.; Barnes, H. Michael; ...

2011-01-01

The objective of this study was to investigate an inorganic nanoparticle impregnation (INI) technique to improve the compatibility between kenaf bast fibers and polyolefin matrices. The Scanning Electron Microscopy (SEM) was used to examine the surface morphology of the INI-treated fibers showing that the CaCO 3 nanoparticle crystals grew onto the fiber surface. Energy-dispersive X-ray spectroscopy (EDS) was used to verify the CaCO 3 nanoparticle deposits on the fiber surface. The tension tests of the individual fiber were conducted, and the results showed that the tensile strength of the fibers increased significantly (more than 20%) after the INI treatments. Polymermore » composites were fabricated using the INI-treated fiber as reinforcement and polypropylene (PP) as the matrix. The results showed that the INI treatments improved the compatibility between kenaf fibers and PP matrix. The tensile modulus and tensile strength of the composites reinforced with INI-treated fibers increased by 25.9% and 10.4%, respectively, compared to those reinforced with untreated kenaf fibers.« less

Investigating effects of nano cerium oxide reinforcement on mechanical properties of composite based on natural rubber

NASA Astrophysics Data System (ADS)

Bao, Le Quoc; Phan, Vu Hoang Giang; Khuyen, Nguyen Quang

2018-04-01

Polymer nanocomposites that based on combination of nanomaterials (such as nanoparticles, nanotubes, nanorods, nanofibers, and nanosheets) and polymeric matrices are receiving great attention in research and application. However, separate and homogenous dispersion rather than aggregates of nanoparticles into matrices meet big difficulty due to large interaction between nanoparticles. The poor dispersion leads to low properties of nanocomposites. In this study, we find out the appropriate method to separately disperse cerium oxides (CeO2) nanoparticles into natural rubber, aiming to increase mechanical properties of natural rubber. The SEM images were used to evaluate the dispersion of nano CeO2 in natural rubber matrix. The mechanical properties of nanocomposites were measured after vulcanization to investigate effects of nano CeO2 amount on prepared composite. The findings exhibited that the addition of CeO2 by dispersion of nano CeO2 in water via ultrasonication before mixing with rubber latex, significantly increase modulus, tear and wear resistance of natural rubber.

Sensing the temperature influence on plasmonic field of metal nanoparticles by photoluminescence of fullerene C{sub 60} in layered C{sub 60}/Au system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeshchenko, Oleg A., E-mail: yes@univ.kiev.ua; Bondarchuk, Illya S.; Kozachenko, Viktor V.

2015-04-21

Influence of temperature on the plasmonic field in the temperature range of 78–278 K was studied employing surface plasmon enhanced photoluminescence from the fullerene C{sub 60} thin film deposited on 2D array of Au nanoparticles. It was experimentally found that temperature dependence of plasmonic enhancement factor of C{sub 60} luminescence decreases monotonically with the temperature increase. Influence of temperature on plasmonic enhancement factor was found to be considerably stronger when the frequency of surface plasmon absorption band of Au nanoparticles and the frequency of fullerene luminescence band are in resonance. Electron-phonon scattering and thermal expansion of Au nanoparticles were considered asmore » two competing physical mechanisms of the temperature dependence of plasmonic field magnitude. The calculations revealed significant prevalence of the electron-phonon scattering. The temperature induced increase in the scattering rate leads to higher plasmon damping that causes the decrease in the magnitude of plasmonic field.« less

Influence of hybrid inorganic/organic mesoporous and nanostructured materials on the cephalosporins' efficacy on different bacterial strains.

PubMed

Carmen Chifiriuc, M; Mihaiescu, D; Ilinca, E; Marutescu, L; Mihaescu, G; Mihai Grumezescu, A

2012-12-01

The aim of this study was to investigate the effect of different hybrid inorganic-organic micro- and nanomaterials (Fe(3)O(4)/PEG(600), Fe(3)O(4)/C(12), ZSM-5) on the antibacterial activity of different cephalosporins against Gram-positive and Gram-negative bacterial strains. The synergic effect of the studied materials was demonstrated by the increase in the growth inhibition zones diameter. All tested hybrid micro- and nanomaterials increased the activity of cefotaxime against Staphylococcus aureus. ZSM-5 increased the activity of cefotaxime and ceftriaxone and Fe(3)O(4)/C(12) that of ceftriaxone against Pseudomonas aeruginosa and S. aureus. The anti-Pseudomonas, anti-Klebsiella pneumoniae and anti-Bacillus subtilis activity of cefoperazone was increased by Fe(3)O(4)/C(12) nanoparticles, while the ZSM-5 improved its anti-Escherichia coli, K. pneumoniae, S. aureus and B. subtilis activity, whereas Fe(3)O(4)/PEG(600) against K. pneumoniae. The anti-K. pneumoniae activity of cefepime was increased by all tested nanoparticles, whereas its anti-B. subtilis and anti-E. coli activity was improved by Fe(3)O(4)/C(12) and Fe(3)O(4)/PEG(600) nanoparticles. In conclusion, both magnetic Fe(3)O(4) nanoparticles, charged outside as extra-shell with the antibiotic as well as ZSM-5 microparticles carrying the antibiotic inside the pores, significantly and specifically improved cephalosporin efficacy. A probable explanation for the increase in the antibiotic efficiency is the better penetration through the cellular wall of the antibiotic charged nanoparticles.

Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO2.

PubMed

Ozmen, Murat; Güngördü, Abbas; Erdemoglu, Sema; Ozmen, Nesrin; Asilturk, Meltem

2015-08-01

The toxic effects of two selected xenobiotics, bisphenol A (BPA) and atrazine (ATZ), were evaluated after photocatalytic degradation using nano-sized, Mn-doped TiO2. Undoped and Mn-doped TiO2 nanoparticles were synthesized. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), UV-vis-diffuse reflectance spectra (DRS), X-ray fluorescence spectroscopy (XRF), and BET surface area. The photocatalytic efficiency of the undoped and Mn-doped TiO2 was evaluated for BPA and ATZ. The toxicity of the synthesized photocatalysts and photocatalytic by-products of BPA and ATZ was determined using frog embryos and tadpoles, zebrafish embryos, and bioluminescent bacteria. Possible toxic effects were also evaluated using selected enzyme biomarkers. The results showed that Mn-doped TiO2 nanoparticles did not cause significant lethality in Xenopus laevis embryos and tadpoles, but nonfiltered samples caused lethality in zebrafish. Furthermore, Mn-doping of TiO2 increased the photocatalytic degradation capability of nanoparticles, and it successfully degraded BPA and AZT, but degradation of AZT caused an increase of the lethal effects on both tadpoles and fish embryos. Degradation of BPA caused a significant reduction of lethal effects, especially after 2-4h of degradation. However, biochemical assays showed that both Mn-doped TiO2 and the degradation by-products caused a significant change of selected biomarkers on X. laevis tadpoles; thus, the ecological risks of Mn-doped TiO2 should be considered due to nanomaterial applications and for spilled nanoparticles in an aquatic ecosystem. Also, the risk of nanoparticles should be considered using indicator reference biochemical markers to verify the environmental health impacts. Copyright © 2015 Elsevier B.V. All rights reserved.

Contrast Ultrasound Targeted Treatment of Gliomas in Mice via Drug-Bearing Nanoparticle Delivery and Microvascular Ablation

PubMed Central

Burke, Caitlin W.; Price, Richard J.

2010-01-01

We are developing minimally-invasive contrast agent microbubble based therapeutic approaches in which the permeabilization and/or ablation of the microvasculature are controlled by varying ultrasound pulsing parameters. Specifically, we are testing whether such approaches may be used to treat malignant brain tumors through drug delivery and microvascular ablation. Preliminary studies have been performed to determine whether targeted drug-bearing nanoparticle delivery can be facilitated by the ultrasound mediated destruction of "composite" delivery agents comprised of 100nm poly(lactide-co-glycolide) (PLAGA) nanoparticles that are adhered to albumin shelled microbubbles. We denote these agents as microbubble-nanoparticle composite agents (MNCAs). When targeted to subcutaneous C6 gliomas with ultrasound, we observed an immediate 4.6-fold increase in nanoparticle delivery in MNCA treated tumors over tumors treated with microbubbles co-administered with nanoparticles and a 8.5 fold increase over non-treated tumors. Furthermore, in many cancer applications, we believe it may be desirable to perform targeted drug delivery in conjunction with ablation of the tumor microcirculation, which will lead to tumor hypoxia and apoptosis. To this end, we have tested the efficacy of non-theramal cavitation-induced microvascular ablation, showing that this approach elicits tumor perfusion reduction, apoptosis, significant growth inhibition, and necrosis. Taken together, these results indicate that our ultrasound-targeted approach has the potential to increase therapeutic efficiency by creating tumor necrosis through microvascular ablation and/or simultaneously enhancing the drug payload in gliomas. PMID:21206463

Contrast ultrasound targeted treatment of gliomas in mice via drug-bearing nanoparticle delivery and microvascular ablation.

PubMed

Burke, Caitlin W; Price, Richard J

2010-12-15

We are developing minimally-invasive contrast agent microbubble based therapeutic approaches in which the permeabilization and/or ablation of the microvasculature are controlled by varying ultrasound pulsing parameters. Specifically, we are testing whether such approaches may be used to treat malignant brain tumors through drug delivery and microvascular ablation. Preliminary studies have been performed to determine whether targeted drug-bearing nanoparticle delivery can be facilitated by the ultrasound mediated destruction of "composite" delivery agents comprised of 100nm poly(lactide-co-glycolide) (PLAGA) nanoparticles that are adhered to albumin shelled microbubbles. We denote these agents as microbubble-nanoparticle composite agents (MNCAs). When targeted to subcutaneous C6 gliomas with ultrasound, we observed an immediate 4.6-fold increase in nanoparticle delivery in MNCA treated tumors over tumors treated with microbubbles co-administered with nanoparticles and a 8.5 fold increase over non-treated tumors. Furthermore, in many cancer applications, we believe it may be desirable to perform targeted drug delivery in conjunction with ablation of the tumor microcirculation, which will lead to tumor hypoxia and apoptosis. To this end, we have tested the efficacy of non-theramal cavitation-induced microvascular ablation, showing that this approach elicits tumor perfusion reduction, apoptosis, significant growth inhibition, and necrosis. Taken together, these results indicate that our ultrasound-targeted approach has the potential to increase therapeutic efficiency by creating tumor necrosis through microvascular ablation and/or simultaneously enhancing the drug payload in gliomas.

In vitro and in vivo anti-tumor activities of a gemcitabine derivative carried by nanoparticles

PubMed Central

Sloat, Brian R.; Sandoval, Michael A.; Li, Dong; Chung, Woon-Gye; Lansakara-P., Dharmika S. P.; Proteau, Philip J.; Kiguchi, Kaoru; DiGiovanni, John; Cui, Zhengrong

2011-01-01

Gemcitabine (Gemzar®) is the first line treatment for pancreatic cancer and often used in combination therapy for non-small cell lung, ovarian, and metastatic breast cancers. Although extremely toxic to a variety of tumor cells in culture, the clinical outcome of gemcitabine treatment still needs improvement. In the present study, a new gemcitabine nanoparticle formulation was developed by incorporating a previously reported stearic acid amide derivative of gemcitabine into nanoparticles prepared from lecithin/glyceryl monostearate-in-water emulsions. The stearoyl gemcitabine nanoparticles were cytotoxic to tumor cells in culture, although it took a longer time for the gemcitabine in the nanoparticles to kill tumor cells than for free gemcitabine. In mice with pre-established model mouse or human tumors, the stearoyl gemcitabine nanoparticles were significantly more effective than free gemcitabine in controlling the tumor growth. PEGylation of the gemcitabine nanoparticles with polyethylene glycol (2000) prolonged the circulation of the nanoparticles in blood and increased the accumulation of the nanoparticles in tumor tissues (> 6-fold), but the PEGylated and un-PEGylated gemcitabine nanoparticles showed similar anti-tumor activity in mice. Nevertheless, the nanoparticle formulation was critical for the stearoyl gemcitabine to show a strong anti-tumor activity. It is concluded that for the gemcitabine derivate-containing nanoparticles, cytotoxicity data in culture may not be used to predict their in vivo anti-tumor activity, and this novel gemcitabine nanoparticle formulation has the potential to improve the clinical outcome of gemcitabine treatment. PMID:21371545

Inhibitory effect of zirconium oxide nanoparticles on Candida albicans adhesion to repaired polymethyl methacrylate denture bases and interim removable prostheses: a new approach for denture stomatitis prevention

PubMed Central

Gad, Mohammed M; Al-Thobity, Ahmad M; Shahin, Suliman Y; Alsaqer, Badar T; Ali, Aiman A

2017-01-01

Background Despite drawbacks, cold-cured acrylic resin is still the most common material used in denture repair. Zirconia nanoparticles were among the reinforcements added to increase the strength of the resin. The effect on Candida due to the addition of zirconia nanoparticles to the resin has not been investigated. Purpose The aim of this study was to evaluate the effect of zirconia nanoparticles added to cold-cured acrylic resin on Candida albicans adhesion. Materials and methods A total of 120 acrylic resin specimens with dimensions measuring 22×10×2.5 mm3 were prepared and divided into two equal groups. One group (repair) comprised heat-polymerized specimens that were sectioned at the center and prepared to create a 2 mm repair area that was repaired with cold-cured resin reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. The second group contained intact cold-cured acrylic resin specimens reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. Specimens were incubated at 37°C in artificial saliva containing C. albicans, and the effect of zirconia nanoparticles on C. albicans was assessed using two methods: 1) a slide count method and 2) a direct culture test. Variations in the number of living Candida were observed in relation to the different concentrations of zirconia nanoparticles. Analysis of variance (ANOVA) and post hoc Tukey’s tests were performed for data analysis. If the P-value was ≤0.05, then the difference was considered as statistically significant. Results It was found that C. albicans adhesion to repaired specimens was significantly decreased by the addition of zirconia nanoparticles (P<0.00001) in comparison with the control group. Intact cold-cured groups and groups repaired with cold-cured resin reinforced with 7.5% wt zirconia nanoparticles showed the lowest Candida count. Tukey’s test showed a significant difference between the repaired group and the intact cold-cured group, while the later demonstrated a lower Candida count. Conclusion The addition of zirconia nanoparticles to cold-cured acrylic resin is an effective method for reducing Candida adhesion to repaired polymethyl methacrylate (PMMA) denture bases and cold-cured removable prosthesis. Clinical significance Based on the results of the current study, zirconia nanoparticles have an antifungal effect, which could be incorporated in the repair material for repairing denture bases and in PMMA removable prostheses as a possible approach for denture stomatitis prevention. PMID:28814859

Biodegradable nanoparticles for improved kidney bioavailability of rhein: preparation, characterization, plasma, and kidney pharmacokinetics.

PubMed

Wei, Yinghui; Luo, Xiaoting; Guan, Jiani; Ma, Jianping; Zhong, Yicong; Luo, Jingwen; Li, Fanzhu

2017-11-01

The aim of this work is to develop biodegradable nanoparticles for improved kidney bioavailability of rhein (RH). RH-loaded nanoparticles were prepared using an emulsification solvent evaporation method and fully characterized by several techniques. Kidney pharmacokinetics was assessed by implanting a microdialysis probe in rat's kidney cortex. Blood samples were simultaneously collected (via femoral artery) for assessing plasma pharmacokinetics. Optimized nanoparticles were small, with a mean particle size of 132.6 ± 5.95 nm, and homogeneously dispersed. The charge on the particles was nearly zero, the encapsulation efficiency was 62.71 ± 3.02%, and the drug loading was 1.56 ± 0.15%. In vitro release of RH from the nanoparticles showed an initial burst release followed by a sustained release. Plasma and kidney pharmacokinetics showed that encapsulation of RH into nanoparticles significantly increased its kidney bioavailability (AUC kidney /AUC plasma  = 0.586 ± 0.072), clearly indicating that nanoparticles are a promising strategy for kidney drug delivery.

Synthesis of Glycyrrhetinic Acid-Modified Chitosan 5-Fluorouracil Nanoparticles and Its Inhibition of Liver Cancer Characteristics in Vitro and in Vivo

PubMed Central

Cheng, Mingrong; Gao, Xiaoyan; Wang, Yong; Chen, Houxiang; He, Bing; Xu, Hongzhi; Li, Yingchun; Han, Jiang; Zhang, Zhiping

2013-01-01

Nanoparticle drug delivery (NDDS) is a novel system in which the drugs are delivered to the site of action by small particles in the nanometer range. Natural or synthetic polymers are used as vectors in NDDS, as they provide targeted, sustained release and biodegradability. Here, we used the chitosan and hepatoma cell-specific binding molecule, glycyrrhetinic acid (GA), to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS). The synthetic product was confirmed by Fourier transformed infrared spectroscopy (FT-IR) and 1H-nuclear magnetic resonance (1H-NMR). By combining GA-CTS and 5-FU (5-fluorouracil), we obtained a GA-CTS/5-FU nanoparticle, with a particle size of 217.2 nm, a drug loading of 1.56% and a polydispersity index of 0.003. The GA-CTS/5-FU nanoparticle provided a sustained release system comprising three distinct phases of quick, steady and slow release. We demonstrated that the nanoparticle accumulated in the liver. In vitro data indicated that it had a dose- and time-dependent anti-cancer effect. The effective drug exposure time against hepatic cancer cells was increased in comparison with that observed with 5-FU. Additionally, GA-CTS/5-FU significantly inhibited the growth of drug-resistant hepatoma, which may compensate for the drug-resistance of 5-FU. In vivo studies on an orthotropic liver cancer mouse model demonstrated that GA-CTS/5-FU significantly inhibited tumor growth, resulting in increased survival time. PMID:24048270

Polyethylene glycol (PEG) assisted size-controlled SnO{sub 2} nanoparticles by sol-gel process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tripathi, P., E-mail: ptrip71@yahoo.com; Ahmed, Ateeq; Ali, Tinku

2016-05-23

Tetragonal phase tin oxide (SnO{sub 2}) nanoparticles have been synthesized by sol–gel method using SnCl{sub 4}.5H{sub 2}O and polyethylene glycol (PEG) of different concentration. The phase, size and purity of the final products are characterized by X-ray diffraction (XRD). The morphology is confirmed by scanning electron microscopy (SEM) analysis. There exists relationship between the concentration of PEG and particle size of SnO{sub 2} nanoparticles. Increase in concentration of PEG caused the reduction of particle size of tin oxide nanoparticles. The results suggest that the concentration of PEG plays a significant role in determining the size of SnO{sub 2} nanoparticles synthesizedmore » via this method. The optical property of the product has been explored by Ultraviolet (UV-visible) and Fourier Transform Infrared (FTIR) spectroscopic techniques.« less

Bismuth nanoparticle decorating graphite felt as a high-performance electrode for an all-vanadium redox flow battery.

PubMed

Li, Bin; Gu, Meng; Nie, Zimin; Shao, Yuyan; Luo, Qingtao; Wei, Xiaoliang; Li, Xiaolin; Xiao, Jie; Wang, Chongmin; Sprenkle, Vincent; Wang, Wei

2013-03-13

Employing electrolytes containing Bi(3+), bismuth nanoparticles are synchronously electrodeposited onto the surface of a graphite felt electrode during operation of an all-vanadium redox flow battery (VRFB). The influence of the Bi nanoparticles on the electrochemical performance of the VRFB is thoroughly investigated. It is confirmed that Bi is only present at the negative electrode and facilitates the redox reaction between V(II) and V(III). However, the Bi nanoparticles significantly improve the electrochemical performance of VRFB cells by enhancing the kinetics of the sluggish V(II)/V(III) redox reaction, especially under high power operation. The energy efficiency is increased by 11% at high current density (150 mA·cm(-2)) owing to faster charge transfer as compared with one without Bi. The results suggest that using Bi nanoparticles in place of noble metals offers great promise as high-performance electrodes for VRFB application.

Sodium alginate/gelatin with silica nanoparticles a novel hydrogel for 3D printing

NASA Astrophysics Data System (ADS)

Soni, Raghav; Roopavath, Uday Kiran; Mahanta, Urbashi; Deshpande, A. S.; Rath, S. N.

2018-05-01

Sodium alginate/gelatin hydrogels are promising materials for 3D bio-printing due to its good biocompatibility and biodegradability. Gelatin is used for thermal crosslinking and its cell adhesion properties. Hence patient specific sodium alginate/gelatin hydrogel scaffolds can be bio-fabricated in a temperature range of 4-14 oC. In this study we made an attempt to introduce silica (SiO2) nanoparticles in the polymer network of sodium alginate (2.5%)/gelatin (8%) hydrogel at different concentrations (w/v) as 0%, 1.25%, 2.5%, 5%, and 7.5%. The effect of silica nanoparticles on viscosity, swelling behavior, and degradation rate are analyzed. Hydrogels with 5% silica nanoparticles show significantly less swelling and degradation when compared to other concentrations. The viscosity of the hydrogels gradually increases up to 5% addition of silica nanoparticles enhancing the stability of 3D printed structures.

Enhanced emission of nile red fluorescent nanoparticles embedded in hybrid sol-gel glasses.

PubMed

Ferrer, Maria L; del Monte, Francisco

2005-01-13

Highly fluorescent Nile Red (NR) nanoparticles embedded in a hybrid sol-gel glass are reported. The crystallite growth within the confined system created by the porous hybrid matrix results in NR nanoparticles of averaged dimensions below 36 nm. The preparation process allows for the control of both the conformation adopted by single NR molecules prior to aggregation (e.g., near planar) and the configuration of the aggregates (e.g., oblique with phi < 54.7 degrees) prior to their assembly in the supramolecular architecture which ultimately forms the nanoparticles. The full preservation of the fluorescent configuration of the aggregates in the nanoparticles is confirmed through the application of the exciton theory, and it is responsible for the significant increase of the fluorescence emission intensity (e.g., up to 525- and 70-fold as compared to that obtained for single NR molecules embedded in pure and hybrid silica glasses, respectively).

Phytochemicals and Biogenic Metallic Nanoparticles as Anticancer Agents

PubMed Central

Rao, Pasupuleti Visweswara; Nallappan, Devi; Madhavi, Kondeti; Rahman, Shafiqur; Jun Wei, Lim; Gan, Siew Hua

2016-01-01

Cancer is a leading cause of death worldwide. Several classes of drugs are available to treat different types of cancer. Currently, researchers are paying significant attention to the development of drugs at the nanoscale level to increase their target specificity and to reduce their concentrations. Nanotechnology is a promising and growing field with multiple subdisciplines, such as nanostructures, nanomaterials, and nanoparticles. These materials have gained prominence in science due to their size, shape, and potential efficacy. Nanomedicine is an important field involving the use of various types of nanoparticles to treat cancer and cancerous cells. Synthesis of nanoparticles targeting biological pathways has become tremendously prominent due to the higher efficacy and fewer side effects of nanodrugs compared to other commercial cancer drugs. In this review, different medicinal plants and their active compounds, as well as green-synthesized metallic nanoparticles from medicinal plants, are discussed in relation to their anticancer activities. PMID:27057273

Physics responsible for heating efficiency and self-controlled temperature rise of magnetic nanoparticles in magnetic hyperthermia therapy.

PubMed

Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam

2018-03-01

Magnetic nanoparticles as heat-generating nanosources in hyperthermia treatment are still faced with many drawbacks for achieving sufficient clinical potential. In this context, increase in heating ability of magnetic nanoparticles in a biologically safe alternating magnetic field and also approach to a precise control on temperature rise are two challenging subjects so that a significant part of researchers' efforts has been devoted to them. Since a deep understanding of Physics concepts of heat generation by magnetic nanoparticles is essential to develop hyperthermia as a cancer treatment with non-adverse side effects, this review focuses on different mechanisms responsible for heat dissipation in a radio frequency magnetic field. Moreover, particular attention is given to ferrite-based nanoparticles because of their suitability in radio frequency magnetic fields. Also, the key role of Curie temperature in suppressing undesired temperature rise is highlighted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phase behavior and orientational ordering in block copolymers doped with anisotropic nanoparticles

NASA Astrophysics Data System (ADS)

Osipov, M. A.; Gorkunov, M. V.; Berezkin, A. V.; Kudryavtsev, Y. V.

2018-04-01

A molecular field theory and coarse-grained computer simulations with dissipative particle dynamics have been used to study the spontaneous orientational ordering of anisotropic nanoparticles in the lamellar and hexagonal phases of diblock copolymers and the effect of nanoparticles on the phase behavior of these systems. Both the molecular theory and computer simulations indicate that strongly anisotropic nanoparticles are ordered orientationally mainly in the boundary region between the domains and the nematic order parameter possesses opposite signs in adjacent domains. The orientational order is induced by the boundary and by the interaction between nanoparticles and the monomer units in different domains. In simulations, sufficiently long and strongly selective nanoparticles are ordered also inside the domains. The nematic order parameter and local concentration profiles of nanoparticles have been calculated numerically using the model of a nanoparticle with two interaction centers and also determined using the results of computer simulations. A number of phase diagrams have been obtained which illustrate the effect of nanoparticle selectivity and molar fraction of the stability ranges of various phases. Different morphologies have been identified by analyzing the static structure factor and a phase diagram has been constructed in coordinates' nanoparticle concentration-copolymer composition. Orientational ordering of even a small fraction of nanoparticles may result in a significant increase of the dielectric anisotropy of a polymer nanocomposite, which is important for various applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mthethwa, T.P.; Moloto, M.J., E-mail: mmoloto@uj.ac.za; De Vries, A.

Graphical abstract: SEM images of CdS/PMMA showing coiling as loading of CdS nanoparticles is increased. Thermal stability is increased with increase in %loading of both CdS and CdSe nanoparticles. Research highlights: {yields} TOPO-capped CdS and HDA-capped CdSe nanoparticles were synthesized and fully characterized. {yields} The nanoparticles were mixed with the polymer, PMMA using electrospinning technique using 2, 5 and 10% weight loadings. {yields} The mixture was spun to produce fibres with optical and thermal properties showing significant change and also the increase in loading causing bending or spiraling. {yields} Both TEM images for nanoparticles and SEM for fibres shows themore » morphology and sizes of the particles. -- Abstract: Electrospinning technique was used to fabricate poly(methyl methacrylate) (PMMA) fibres incorporating CdS and CdSe quantum dots (nanoparticles). Different nanoparticle loadings (2, 5 and 10 wt% with respect to PMMA) were used and the effect of the quantum dots on the properties of the fibres was studied. The optical properties of the hybrid composite fibres were investigated by photoluminescence and UV-vis spectrophotometry. Scanning electron microscopy (SEM), X-ray diffraction and FTIR spectrophotometry were also used to investigate the morphology and structure of the fibres. The optical studies showed that the size-tunable optical properties can be achieved in the polymer fibres by addition of quantum dots. SEM images showed that the morphologies of the fibres were dependent on the added amounts of quantum dots. A spiral type of morphology was observed with an increase in the concentration of CdS and CdSe nanoparticles. Less beaded structures and bigger diameter fibres were obtained at higher quantum dot concentrations. X-ray diffractometry detected the amorphous peaks of the polymer and even after the quantum dots were added and the FTIR analysis shows that there was no considerable interaction between the quantum dots and the polymer fibres at low concentration of quantum dots however at higher concentrations some interactions were observed which shows that QDs were present on the surfaces of the fibres.« less

Magnetic properties of La0.95Sr0.05CoO3 nanoparticles

NASA Astrophysics Data System (ADS)

Prakash, Ravi; Shukla, Rishabh; Priyanka, Dhaka, R. S.

2017-05-01

We report the magnetic and structural properties of La(1-x)SrxCoO3 (x = 0 & 0.05) nanoparticles. The analysis of room temperature powder x-ray diffraction confirms the crystalline nature and single phase of the prepared samples. The magnetic measurements show ferromagnetic transition at TC˜85 K, the spontaneous magnetic moment MS ˜172 emu/mol, and the coercive field HC ˜7 kOe in parent compound, which are in agreement with the literature. Interestingly, with hole doping by Sr2+ substitution at La3+ site the magnetization data show drastic changes, as the TC increases to ˜270 K, the value of MS (˜557 emu/mole) increases about three times, whereas, the HC (˜0.6 kOe) decreases. Below TC, the nanoparticles show a much larger FC moment and a significant difference in FC and ZFC (zero field cooled) behaviors. For x = 0.05, we determined the values of effective magnetic moment (µeff = 3.62 µB/Co), the Curie temperature (θCW = -28 K) and the spin state (Savg = 1.38), which are significantly different than LaCoO3. Our study suggests an important role of charge carriers in controlling of intermediate spin state by hole doping in nanoparticles.

Can More Nanoparticles Induce Larger Viscosities of Nanoparticle-Enhanced Wormlike Micellar System (NEWMS)?

PubMed

Zhao, Mingwei; Zhang, Yue; Zou, Chenwei; Dai, Caili; Gao, Mingwei; Li, Yuyang; Lv, Wenjiao; Jiang, Jianfeng; Wu, Yining

2017-09-18

There have been many reports about the thickening ability of nanoparticles on the wormlike micelles in the recent years. Through the addition of nanoparticles, the viscosity of wormlike micelles can be increased. There still exists a doubt: can viscosity be increased further by adding more nanoparticles? To answer this issue, in this work, the effects of silica nanoparticles and temperature on the nanoparticles-enhanced wormlike micellar system (NEWMS) were studied. The typical wormlike micelles (wormlike micelles) are prepared by 50 mM cetyltrimethyl ammonium bromide (CTAB) and 60 mM sodium salicylate (NaSal). The rheological results show the increase of viscoelasticity in NEWMS by adding nanoparticles, with the increase of zero-shear viscosity and relaxation time. However, with the further increase of nanoparticles, an interesting phenomenon appears. The zero-shear viscosity and relaxation time reach the maximum and begin to decrease. The results show a slight increasing trend for the contour length of wormlike micelles by adding nanoparticles, while no obvious effect on the entanglement and mesh size. In addition, with the increase of temperature, remarkable reduction of contour length and relaxation time can be observed from the calculation. NEWMS constantly retain better viscoelasticity compared with conventional wormlike micelles without silica nanoparticles. According to the Arrhenius equation, the activation energy E a shows the same increase trend of NEWMS. Finally, a mechanism is proposed to explain this interesting phenomenon.

Therapeutic effect of Aloe vera and silver nanoparticles on acid-induced oral ulcer in gamma-irradiated mice.

PubMed

El-Batal, Ahmed Ibrahim; Ahmed, Salwa Farid

2018-02-05

Radiation combined injury, a life-threatening condition, has higher mortality than simple radiation injury. The aim of the present study was to analyze the efficiency of Aloe vera and silver nanoparticles in improving the healing of ulcerated oral mucosa after irradiation. Thirty male Albino mice were divided into five groups: control, radiation, Aloe vera (AV), silver nanoparticles (NS), and AV+NS. The mice were exposed to whole body 6Gy gamma-radiation. After one hour, 20% acetic acid was injected into the submucosal layer of the lower lip for ulcer induction. The animals received topical treatment with the assigned substances for 5 days. Lip specimens were subjected to hematoxylin and eosin and anti alpha-smooth muscle actin immunohistochemical staining. Results demonstrated occurance of ulcer three days post irradiation in all groups except in the AV+NS group where only epithelial detachment was developed. After seven days, data revealed persistent ulcer in radiation group, and almost normal epithelium in the AV+NS group. A significant reduction of epithelial thickness was detected in all groups at the third day as compared to control. At the seventh day, only the AV+NS group restored the epithelial thickness. Area percent of alpha-smooth muscle actin expression was significantly decreased in radiation group at the third day followed by significant increase at the seventh day. However, all treatment groups showed significant increase in alpha-smooth muscle actin at the third day, which decreased to normal level at the seventh day. Our study demonstrated the efficiency of Aloe vera and silver nanoparticles in enhancing ulcer healing after irradiation.

Shape-Related Toxicity of Titanium Dioxide Nanofibres

PubMed Central

Allegri, Manfredi; Bianchi, Massimiliano G.; Chiu, Martina; Varet, Julia; Costa, Anna L.; Ortelli, Simona; Blosi, Magda; Bussolati, Ovidio; Poland, Craig A.; Bergamaschi, Enrico

2016-01-01

Titanium dioxide (TiO2) nanofibres are a novel fibrous nanomaterial with increasing applications in a variety of fields. While the biological effects of TiO2 nanoparticles have been extensively studied, the toxicological characterization of TiO2 nanofibres is far from being complete. In this study, we evaluated the toxicity of commercially available anatase TiO2 nanofibres using TiO2 nanoparticles (NP) and crocidolite asbestos as non-fibrous or fibrous benchmark materials. The evaluated endpoints were cell viability, haemolysis, macrophage activation, trans-epithelial electrical resistance (an indicator of the epithelial barrier competence), ROS production and oxidative stress as well as the morphology of exposed cells. The results showed that TiO2 nanofibres caused a cell-specific, dose-dependent decrease of cell viability, with larger effects on alveolar epithelial cells than on macrophages. The observed effects were comparable to those of crocidolite, while TiO2 NP did not decrease cell viability. TiO2 nanofibres were also found endowed with a marked haemolytic activity, at levels significantly higher than those observed with TiO2 nanoparticles or crocidolite. Moreover, TiO2 nanofibres and crocidolite, but not TiO2 nanoparticles, caused a significant decrease of the trans-epithelial electrical resistance of airway cell monolayers. SEM images demonstrated that the interaction with nanofibres and crocidolite caused cell shape perturbation with the longest fibres incompletely or not phagocytosed. The expression of several pro-inflammatory markers, such as NO production and the induction of Nos2 and Ptgs2, was significantly increased by TiO2 nanofibres, as well as by TiO2 nanoparticles and crocidolite. This study indicates that TiO2 nanofibres had significant toxic effects and, for most endpoints with the exception of pro-inflammatory changes, are more bio-active than TiO2 nanoparticles, showing the relevance of shape in determining the toxicity of nanomaterials. Given that several toxic effects of TiO2 nanofibres appear comparable to those observed with crocidolite, the possibility that they exert length dependent toxicity in vivo seems worthy of further investigation. PMID:26999274

Influence of structure of iron nanoparticles in aggregates on their magnetic properties

PubMed Central

2011-01-01

Zero-valent iron nanoparticles rapidly aggregate. One of the reasons is magnetic forces among the nanoparticles. Magnetic field around particles is caused by composition of the particles. Their core is formed from zero-valent iron, and shell is a layer of magnetite. The magnetic forces contribute to attractive forces among the nanoparticles and that leads to increasing of aggregation of the nanoparticles. This effect is undesirable for decreasing of remediation properties of iron particles and limited transport possibilities. The aggregation of iron nanoparticles was established for consequent processes: Brownian motion, sedimentation, velocity gradient of fluid around particles and electrostatic forces. In our previous work, an introduction of influence of magnetic forces among particles on the aggregation was presented. These forces have significant impact on the rate of aggregation. In this article, a numerical computation of magnetic forces between an aggregate and a nanoparticle and between two aggregates is shown. It is done for random position of nanoparticles in an aggregate and random or arranged directions of magnetic polarizations and for structured aggregates with arranged vectors of polarizations. Statistical computation by Monte Carlo is done, and range of dominant area of magnetic forces around particles is assessed. PMID:21917152

Polymer-encapsulated organic nanoparticles for fluorescence and photoacoustic imaging.

PubMed

Li, Kai; Liu, Bin

2014-09-21

Polymer encapsulated organic nanoparticles have recently attracted increasing attention in the biomedical field because of their unique optical properties, easy fabrication and outstanding performance as imaging and therapeutic agents. Of particular importance is the polymer encapsulated nanoparticles containing conjugated polymers (CP) or fluorogens with aggregation induced emission (AIE) characteristics as the core, which have shown significant advantages in terms of tunable brightness, superb photo- and physical stability, good biocompatibility, potential biodegradability and facile surface functionalization. In this review, we summarize the latest advances in the development of polymer encapsulated CP and AIE fluorogen nanoparticles, including preparation methods, material design and matrix selection, nanoparticle fabrication and surface functionalization for fluorescence and photoacoustic imaging. We also discuss their specific applications in cell labeling, targeted in vitro and in vivo imaging, blood vessel imaging, cell tracing, inflammation monitoring and molecular imaging. We specially focus on strategies to fine-tune the nanoparticle property (e.g. size and fluorescence quantum yield) through precise engineering of the organic cores and careful selection of polymer matrices. The review also highlights the merits and limitations of these nanoparticles as well as strategies used to overcome the limitations. The challenges and perspectives for the future development of polymer encapsulated organic nanoparticles are also discussed.

Folate receptor-mediated boron-10 containing carbon nanoparticles as potential delivery vehicles for boron neutron capture therapy of nonfunctional pituitary adenomas.

PubMed

Dai, Congxin; Cai, Feng; Hwang, Kuo Chu; Zhou, Yongmao; Zhang, Zizhu; Liu, Xiaohai; Ma, Sihai; Yang, Yakun; Yao, Yong; Feng, Ming; Bao, Xinjie; Li, Guilin; Wei, Junji; Jiao, Yonghui; Wei, Zhenqing; Ma, Wenbin; Wang, Renzhi

2013-02-01

Invasive nonfunctional pituitary adenomas (NFPAs) are difficult to completely resect and often develop tumor recurrence after initial surgery. Currently, no medications are clinically effective in the control of NFPA. Although radiation therapy and radiosurgery are useful to prevent tumor regrowth, they are frequently withheld because of severe complications. Boron neutron capture therapy (BNCT) is a binary radiotherapy that selectively and maximally damages tumor cells without harming the surrounding normal tissue. Folate receptor (FR)-targeted boron-10 containing carbon nanoparticles is a novel boron delivery agent that can be selectively taken up by FR-expressing cells via FR-mediated endocytosis. In this study, FR-targeted boron-10 containing carbon nanoparticles were selectively taken up by NFPAs cells expressing FR but not other types of non-FR expressing pituitary adenomas. After incubation with boron-10 containing carbon nanoparticles and following irradiation with thermal neutrons, the cell viability of NFPAs was significantly decreased, while apoptotic cells were simultaneously increased. However, cells administered the same dose of FR-targeted boron-10 containing carbon nanoparticles without neutron irradiation or received the same neutron irradiation alone did not show significant decrease in cell viability or increase in apoptotic cells. The expression of Bcl-2 was down-regulated and the expression of Bax was up-regulated in NFPAs after treatment with FR-mediated BNCT. In conclusion, FR-targeted boron-10 containing carbon nanoparticles may be an ideal delivery system of boron to NFPAs cells for BNCT. Furthermore, our study also provides a novel insight into therapeutic strategies for invasive NFPA refractory to conventional therapy, while exploring these new applications of BNCT for tumors, especially benign tumors.

Efficient Intracellular Delivery of Molecules with High Cell Viability Using Nanosecond-Pulsed Laser-Activated Carbon Nanoparticles

PubMed Central

2015-01-01

Conventional physical and chemical methods that efficiently deliver molecules into cells are often associated with low cell viability. In this study, we evaluated the cellular effects of carbon nanoparticles believed to emit photoacoustic waves due to nanosecond-pulse laser activation to test the hypothesis that this method could achieve efficient intracellular delivery while maintaining high cell viability. Suspensions of DU145 human prostate carcinoma cells, carbon black (CB) nanoparticles, and calcein were exposed to 5–9 ns long laser pulses of near-infrared (1064 nm wavelength) light and then analyzed by flow cytometry for intracellular uptake of calcein and cell viability by propidium iodide staining. We found that intracellular uptake increased and in some cases saturated at high levels with only small losses in cell viability as a result of increasing laser fluence, laser exposure time, and as a unifying parameter, the total laser energy. Changing interpulse spacing between 0.1 and 10 s intervals showed no significant change in bioeffects, suggesting that the effects of each pulse were independent when spaced by at least 0.1 s intervals. Pretreatment of CB nanoparticles to intense laser exposure followed by mixing with cells also had no significant effect on uptake or viability. Similar uptake and viability were seen when CB nanoparticles were substituted with India ink, when DU145 cells were substituted with H9c2 rat cardiomyoblast cells, and when calcein was substituted with FITC-dextran. The best laser exposure conditions tested led to 88% of cells with intracellular uptake and close to 100% viability, indicating that nanosecond-pulse laser-activated carbon nanoparticles can achieve efficient intracellular delivery while maintaining high cell viability. PMID:24547946

Effects of subtoxic concentrations of TiO{sub 2} and ZnO nanoparticles on human lymphocytes, dendritic cells and exosome production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andersson-Willman, Britta; Gehrmann, Ulf; Cansu, Zekiye

Metal oxide nanoparticles are widely used in the paint and coating industry as well as in cosmetics, but the knowledge of their possible interactions with the immune system is very limited. Our aims were to investigate if commercially available TiO{sub 2} and ZnO nanoparticles may affect different human immune cells and their production of exosomes, nano-sized vesicles that have a role in cell to cell communication. We found that the TiO{sub 2} or ZnO nanoparticles at concentrations from 1 to 100 μg/mL did not affect the viability of primary human peripheral blood mononuclear cells (PBMC). In contrast, monocyte-derived dendritic cellsmore » (MDDC) reacted with a dose dependent increase in cell death and caspase activity to ZnO but not to TiO{sub 2} nanoparticles. Non-toxic exposure, 10 μg/mL, to TiO{sub 2} and ZnO nanoparticles did not significantly alter the phenotype of MDDC. Interestingly, ZnO but not TiO{sub 2} nanoparticles induced a down regulation of FcγRIII (CD16) expression on NK-cells in the PBMC population, suggesting that subtoxic concentrations of ZnO nanoparticles might have an effect on FcγR-mediated immune responses. The phenotype and size of exosomes produced by PBMC or MDDC exposed to the nanoparticles were similar to that of exosomes harvested from control cultures. TiO{sub 2} or ZnO nanoparticles could not be detected within or associated to exosomes as analyzed with TEM. We conclude that TiO{sub 2} and ZnO nanoparticles differently affect immune cells and that evaluations of nanoparticles should be performed even at subtoxic concentrations on different primary human immune cells when investigating potential effects on immune functions. -- Highlights: ► ZnO nanoparticles induce cell death of MDDC but not of PBMC. ► ZnO nanoparticles induce caspase activation and DNA fragmentation in MDDC. ► TiO{sub 2} nanoparticles are taken up by MDDC but have no effect on their phenotype. ► ZnO nanoparticles induce a significant reduction of CD16 expression on NK cells. ► ZnO and TiO{sub 2} nanoparticles have no effect on exosomes produced by MDDC or PBMC.« less

Nanoparticle mediated brain targeted delivery of gallic acid: in vivo behavioral and biochemical studies for improved antioxidant and antidepressant-like activity.

PubMed

Nagpal, Kalpana; Singh, Shailendra Kumar; Mishra, Dina Nath

2012-11-01

Gallic acid had been reported to possess antidepressant like activity, which may be attributed to its CNS effects like increase in reduced glutathione levels, increased catalase activity and decreased malonaldehyde levels in brain. This study was designed to enhance the antidepressant-like activity of gallic acid (GA) using nanoparticulate delivery system in swiss male albino mice and to explore the possible underlying mechanisms for this activity. GA loaded chitosan nanoparticles (GANP) and corresponding tween 80 coated batch (cGANP) were formulated for brain targeting of GA and characterized for physicochemical parameters, morphology, differential scanning calorimetry and in vitro drug release. GA, GANP, cGANP (dose equivalent to GA 10 mg/kg, i.p.) and positive control drug, Fluoxetine (10 mg/kg, i.p.) were administered for successive seven days to male swiss albino mice. Then, the in vivo antidepressant-like activity was evaluated using Despair Swim Test (DST) and Tail Suspension Test (TST); along with the evaluation of MAO-A activity, reduced glutathione, malonaldehyde level, catalase and locomotor activity in mice. KEYFINDINGS: cGANP (equivalent to 10 mg/kg, i.p.) significantly decreased immobility period of mice in DST and TST, indicating significant antidepressant-like activity. There was no significant effect on locomotor activity of the mice by GA and its nanoparticle formulations. cGANP (10 mg/kg, i.p.) significantly decreased Monoamine oxidase-A (MAO-A) activity, malondialdehyde levels, and catalase activity in mice. GA possess significant antidepressant like activity and ligand coated nanoparticle approach with improved brain targeting may serve as an effective approach to enhance such effect.

UNS S31603 Stainless Steel Tungsten Inert Gas Welds Made with Microparticle and Nanoparticle Oxides

PubMed Central

Tseng, Kuang-Hung; Lin, Po-Yu

2014-01-01

The purpose of this study was to investigate the difference between tungsten inert gas (TIG) welding of austenitic stainless steel assisted by microparticle oxides and that assisted by nanoparticle oxides. SiO2 and Al2O3 were used to investigate the effects of the thermal stability and the particle size of the activated compounds on the surface appearance, geometric shape, angular distortion, delta ferrite content and Vickers hardness of the UNS S31603 stainless steel TIG weld. The results show that the use of SiO2 leads to a satisfactory surface appearance compared to that of the TIG weld made with Al2O3. The surface appearance of the TIG weld made with nanoparticle oxide has less flux slag compared with the one made with microparticle oxide of the same type. Compared with microparticle SiO2, the TIG welding with nanoparticle SiO2 has the potential benefits of high joint penetration and less angular distortion in the resulting weldment. The TIG welding with nanoparticle Al2O3 does not result in a significant increase in the penetration or reduction of distortion. The TIG welding with microparticle or nanoparticle SiO2 uses a heat source with higher power density, resulting in a higher ferrite content and hardness of the stainless steel weld metal. In contrast, microparticle or nanoparticle Al2O3 results in no significant difference in metallurgical properties compared to that of the C-TIG weld metal. Compared with oxide particle size, the thermal stability of the oxide plays a significant role in enhancing the joint penetration capability of the weld, for the UNS S31603 stainless steel TIG welds made with activated oxides. PMID:28788704

UNS S31603 Stainless Steel Tungsten Inert Gas Welds Made with Microparticle and Nanoparticle Oxides.

PubMed

Tseng, Kuang-Hung; Lin, Po-Yu

2014-06-20

The purpose of this study was to investigate the difference between tungsten inert gas (TIG) welding of austenitic stainless steel assisted by microparticle oxides and that assisted by nanoparticle oxides. SiO₂ and Al₂O₃ were used to investigate the effects of the thermal stability and the particle size of the activated compounds on the surface appearance, geometric shape, angular distortion, delta ferrite content and Vickers hardness of the UNS S31603 stainless steel TIG weld. The results show that the use of SiO₂ leads to a satisfactory surface appearance compared to that of the TIG weld made with Al₂O₃. The surface appearance of the TIG weld made with nanoparticle oxide has less flux slag compared with the one made with microparticle oxide of the same type. Compared with microparticle SiO₂, the TIG welding with nanoparticle SiO₂ has the potential benefits of high joint penetration and less angular distortion in the resulting weldment. The TIG welding with nanoparticle Al₂O₃ does not result in a significant increase in the penetration or reduction of distortion. The TIG welding with microparticle or nanoparticle SiO₂ uses a heat source with higher power density, resulting in a higher ferrite content and hardness of the stainless steel weld metal. In contrast, microparticle or nanoparticle Al₂O₃ results in no significant difference in metallurgical properties compared to that of the C-TIG weld metal. Compared with oxide particle size, the thermal stability of the oxide plays a significant role in enhancing the joint penetration capability of the weld, for the UNS S31603 stainless steel TIG welds made with activated oxides.

Enthalpic and Entropic Competition in Blends of Self-Suspended Hairy Nanoparticles

NASA Astrophysics Data System (ADS)

Choudhury, Snehashis; Agrawal, Akanksha; Archer, Lynden

Self-suspended hairy nanoparticles, where polymer chains are grafted onto nanoparticles, have attracted significant recent attention. These materials have been reported to manifest several interesting phenomena like thermal jamming, slowing-down of polymer chain dynamics, as well as small-strain stress overshoots during start-up of steady shear. The entropic penalty on tethered polymers produced by the requirement that they fill the space between the nanoparticle cores explain most of these behaviors. Here, we show that the entropic attraction between tethered polymer chains can be manipulated in mixtures of hairy nanoparticles using different polymer chemistry to design materials with unusual characteristics. Specifically, the degree of interpenetration of polymer chains can be controlled by tuning their interaction parameter (χ) . For SiO2-PEG/SiO2-PMMA blends, oscillatory rheological measurements show that the plateau modulus and yielding energy are significantly increased, while an opposite effect is seen with SiO2-PEG/SiO2-PI blends. More subtle effects of this enthalpy-entropy competition are well captured in Dielectric Spectroscopy measurements and SAXS experiments that can be used to quantify the degree of stretch and interdigitation of polymer chains.

Synthesis and characterization of amino acid-functionalized calcium phosphate nanoparticles for siRNA delivery.

PubMed

Bakan, Feray; Kara, Goknur; Cokol Cakmak, Melike; Cokol, Murat; Denkbas, Emir Baki

2017-10-01

Small interfering RNAs (siRNA) are short nucleic acid fragments of about 20-27 nucleotides, which can inhibit the expression of specific genes. siRNA based RNAi technology has emerged as a promising method for the treatment of a variety of diseases. However, a major limitation in the therapeutic use of siRNA is its rapid degradation in plasma and cellular cytoplasm, resulting in short half-life. In addition, as siRNA molecules cannot penetrate into the cell efficiently, it is required to use a carrier system for its delivery. In this work, chemically and morphologically different calcium phosphate (CaP) nanoparticles, including spherical-like hydroxyapatite (HA-s), needle-like hydroxyapatite (HA-n) and calcium deficient hydroxyapatite (CDHA) nanoparticles were synthesized by the sol-gel technique and the effects of particle characteristics on the binding capacity of siRNA were investigated. In order to enhance the gene loading efficiency, the nanoparticles were functionalized with arginine and the morphological and their structural characteristics were analyzed. The addition of arginine did not significantly change the particle sizes; however, it provided a significantly increased binding of siRNA for all types of CaP nanoparticles, as revealed by spectrophotometric measurements analysis. Arginine functionalized HA-n nanoparticles showed the best binding behavior with siRNA among the other nanoparticles due to its high, positive zeta potential (+18.8mV) and high surface area of Ca ++ rich "c" plane. MTT cytotoxicity assays demonstrated that all the nanoparticles tested herein were biocompatible. Our results suggest that high siRNA entrapment in each of the three modified non-toxic CaP nanoparticles make them promising candidates as a non-viral vector for delivering therapeutic siRNA molecules to treat cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Significant Enhancement of the Chiral Correlation Length in Nematic Liquid Crystals by Gold Nanoparticle Surfaces Featuring Axially Chiral Binaphthyl Ligands.

PubMed

Mori, Taizo; Sharma, Anshul; Hegmann, Torsten

2016-01-26

Chirality is a fundamental scientific concept best described by the absence of mirror symmetry and the inability to superimpose an object onto its mirror image by translation and rotation. Chirality is expressed at almost all molecular levels, from single molecules to supramolecular systems, and present virtually everywhere in nature. Here, to explore how chirality propagates from a chiral nanoscale surface, we study gold nanoparticles functionalized with axially chiral binaphthyl molecules. In particular, we synthesized three enantiomeric pairs of chiral ligand-capped gold nanoparticles differing in size, curvature, and ligand density to tune the chirality transfer from nanoscale solid surfaces to a bulk anisotropic liquid crystal medium. Ultimately, we are examining how far the chirality from a nanoparticle surface reaches into a bulk material. Circular dichroism spectra of the gold nanoparticles decorated with binaphthyl thiols confirmed that the binaphthyl moieties form a cisoid conformation in isotropic organic solvents. In the chiral nematic liquid crystal phase, induced by dispersing the gold nanoparticles into an achiral anisotropic nematic liquid crystal solvent, the binaphthyl moieties on the nanoparticle surface form a transoid conformation as determined by imaging the helical twist direction of the induced cholesteric phase. This suggests that the ligand density on the nanoscale metal surfaces provides a dynamic space to alter and adjust the helicity of binaphthyl derivatives in response to the ordering of the surrounding medium. The helical pitch values of the induced chiral nematic phase were determined, and the helical twisting power (HTP) of the chiral gold nanoparticles calculated to elucidate the chirality transfer efficiency of the binaphthyl ligand capped gold nanoparticles. Remarkably, the HTP increases with increasing diameter of the particles, that is, the efficiency of the chirality transfer of the binaphthyl units bound to the nanoparticle surface is diminished as the size of the particle is reduced. However, in comparison to the free ligands, per chiral molecule all tested gold nanoparticles induce helical distortions in a 10- to 50-fold larger number of liquid crystal host molecules surrounding each particle, indicating a significantly enhanced chiral correlation length. We propose that both the helicity and the chirality transfer efficiency of axially chiral binaphthyl derivatives can be controlled at metal nanoparticle surfaces by adjusting the particle size and curvature as well as the number and density of the chiral ligands to ultimately measure and tune the chiral correlation length.

Significant increase of Curie temperature in nano-scale BaTiO{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yueliang; Liao, Zhenyu; Fang, Fang

2014-11-03

The low Curie temperature (T{sub c} = 130 °C) of bulk BaTiO{sub 3} greatly limits its applications. In this work, the phase structures of BaTiO{sub 3} nanoparticles with sizes ranging from 2.5 nm to 10 nm were studied at various temperatures by using aberration-corrected transmission electron microscopy (TEM) equipped with an in-situ heating holder. The results implied that each BaTiO{sub 3} nanoparticle was composed of different phases, and the ferroelectric ones were observed in the shells due to the complicated surface structure. The ferroelectric phases in BaTiO{sub 3} nanoparticles remained at 600 °C, suggesting a significant increase of T{sub c}. Based on the in-situ TEM resultsmore » and the data reported by others, temperature-size phase diagrams for BaTiO{sub 3} particles and ceramics were proposed, showing that the phase transition became diffused and the T{sub c} obviously increased with decreasing size. The present work sheds light on the design and fabrication of advanced devices for high temperature applications.« less

Insights into the complex interaction between hydrophilic nanoparticles and ionic surfactants at the liquid/air interface.

PubMed

Jin, Jingyu; Li, Xiaoyan; Geng, Jiafeng; Jing, Dengwei

2018-06-06

Combinations of nanoparticles and surfactants have been widely employed in many industrial processes, i.e., boiling and condensation in heat transfer and hydraulic fracturing in shale oil and gas production, etc. However, the underlying mechanism for various phenomena resulting from the addition of nanoparticles into the surfactant solutions is still unclear. For instance, there are contradictory conclusions from the literature regarding the variations of surface tension upon the addition of nanoparticles into surfactant solutions. In this work, the dominating factors determining if the surface activity of the surfactant solution will increase or conversely decrease when adding certain kinds of nanoparticles have been investigated. Two typical hydrophilic nanoparticles, SiO2 and TiO2 with anionic or cationic surfactants, respectively, have been considered. The surface tension has been measured in a wide range of nanoparticle and surfactant concentrations. It was found that the surface tension of the ionic surfactant solution can be further reduced only if nanoparticles of the same charge were added. For instance, a system containing 0.25 CMC SDS and 1 wt% SiO2 behaves similar to a 0.34 CMC SDS-only solution. Interestingly, the observed synergistic effect is found to be more significant if the surfactant concentration is much lower than its CMC for a given nanoparticle content. Moreover, the effect is perfectly reversible. When the nanoparticles were separated from the system, the surface tension values recovered fully to that of the pure surfactants. If nanoparticles of opposite charge were added, however, the surface tension of the surfactant solution increased. Zeta potential measurement and centrifugal treatment have been employed to reveal the interplay between nanoparticles and surfactants and the adsorption behavior of their assemblies at the liquid/air interface. Based on the experimental outcomes, a possible physical mechanism was proposed. It was concluded that the electrostatic repulsion between surfactant molecules and nanoparticles should be the dominant factor responsible for the observed reversible synergistic effect. Our study is expected to contribute to a better understanding of the interfacial phenomenon in nanoparticle-surfactant complex systems.

Antibacterial activity of silver and zinc nanoparticles against Vibrio cholerae and enterotoxic Escherichia coli.

PubMed

Salem, Wesam; Leitner, Deborah R; Zingl, Franz G; Schratter, Gebhart; Prassl, Ruth; Goessler, Walter; Reidl, Joachim; Schild, Stefan

2015-01-01

Vibrio cholerae and enterotoxic Escherichia coli (ETEC) remain two dominant bacterial causes of severe secretory diarrhea and still a significant cause of death, especially in developing countries. In order to investigate new effective and inexpensive therapeutic approaches, we analyzed nanoparticles synthesized by a green approach using corresponding salt (silver or zinc nitrate) with aqueous extract of Caltropis procera fruit or leaves. We characterized the quantity and quality of nanoparticles by UV-visible wavelength scans and nanoparticle tracking analysis. Nanoparticles could be synthesized in reproducible yields of approximately 10(8) particles/ml with mode particles sizes of approx. 90-100 nm. Antibacterial activity against two pathogens was assessed by minimal inhibitory concentration assays and survival curves. Both pathogens exhibited similar resistance profiles with minimal inhibitory concentrations ranging between 5×10(5) and 10(7) particles/ml. Interestingly, zinc nanoparticles showed a slightly higher efficacy, but sublethal concentrations caused adverse effects and resulted in increased biofilm formation of V. cholerae. Using the expression levels of the outer membrane porin OmpT as an indicator for cAMP levels, our results suggest that zinc nanoparticles inhibit adenylyl cyclase activity. This consequently deceases the levels of this second messenger, which is a known inhibitor of biofilm formation. Finally, we demonstrated that a single oral administration of silver nanoparticles to infant mice colonized with V. cholerae or ETEC significantly reduces the colonization rates of the pathogens by 75- or 100-fold, respectively. Copyright © 2014 The Authors. Published by Elsevier GmbH.. All rights reserved.

Enhanced transport of phenanthrene and 1-naphthol by colloidal graphene oxide nanoparticles in saturated soil.

PubMed

Qi, Zhichong; Hou, Lei; Zhu, Dongqiang; Ji, Rong; Chen, Wei

2014-09-02

With the increasing production and use of graphene oxide, the environmental implications of this new carbonaceous nanomaterial have received much attention. In this study, we found that the presence of low concentrations of graphene oxide nanoparticles (GONPs) significantly enhanced the transport of 1-naphthol in a saturated soil, but affected the transport of phenanthrene to a much smaller extent. The much stronger transport-enhancement effect on 1-naphthol was due to the significant desorption hysteresis (both thermodynamically irreversible adsorption and slow desorption kinetics) of GONP-adsorbed 1-naphthol, likely stemmed from the specific polar interactions (e.g., H-bonding) between 1-naphthol and GONPs. Increasing ionic strength or the presence of Cu(II) ion (a complexing cation) generally increased the transport-enhancement capability of GONPs, mainly by increasing the aggregation of GONPs and thus, sequestering adsorbed contaminant molecules. Interestingly, modifying GONPs with Suwannee River humic acid or sodium dodecyl sulfate had little or essentially no effect on the transport-enhancement capability of GONPs, in contrast with the previously reported profound effects of humic acids and surfactants on the transport-enhancement capability of C60 nanoparticles. Overall, the findings indicate that GONPs in the aquatic environment may serve as an effective carrier for certain organic compounds that can interact with GONPs through strong polar interactions.

Modeling of interactions between nanoparticles and cell membranes

NASA Astrophysics Data System (ADS)

Ban, Young-Min

Rapid development of nanotechnology and ability to manufacture materials and devices with nanometer feature size leads to exciting innovations in many areas including the medical and electronic fields. However, the possible health and environmental impacts of manufactured nanomaterials are not fully known. Recent experimental reports suggest that some of the manufactured nanomaterials, such as fullerenes and carbon nanotubes, are highly toxic even in small concentrations. The goal of the current work is to understand the mechanisms responsible for the toxicity of nanomaterials. In the current study coarse-grained molecular dynamics simulations are employed to investigate the interactions between NPs and cellular membranes at a molecular level. One of the possible toxicity mechanisms of the nanomaterials is membrane disruption. Possibility of membrane disruption exposed to the manufactured nanomaterials are examined by considering chemical reactions and non-reactive physical interactions as chemical as well as physical mechanisms. Mechanisms of transport of carbon-based nanoparticles (fullerene and its derivative) across a phospholipid bilayer are investigated. The free energy profile is obtained using constrained simulations. It is shown that the considered nanoparticles are hydrophobic and therefore they tend to reside in the interior of the lipid bilayer. In addition, the dynamics of the membrane fluctuations is significantly affected by the nanoparticles at the bilayer-water interface. The hydrophobic interaction between the particles and membrane core induces the strong coupling between the nanoparticle motion and membrane deformation. It is observed that the considered nanoparticles affect several physical properties of the membrane. The nanoparticles embedded into the membrane interior lead to the membrane softening, which becomes more significant with increase in CNT length and concentration. The lateral pressure profile and membrane energy in the membrane containing the nanoparticles exhibit localized perturbation around the nanoparticle. The nanoparticles are not likely to affect membrane protein function by the weak perturbation of the internal stress in the membrane. Due to the short-ranged interactions between the nanoparticles, the nanoparticles would not form aggregates inside membranes. The effect of lipid peroxidation on cell membrane deformation is assessed. The peroxidized lipids introduce a perturbation to the internal structure of the membrane leading to higher amplitude of the membrane fluctuations. Higher concentration of the peroxidized lipids induces more significant perturbation. Cumulative effects of lipid peroxidation caused by nanoparticles are examined for the first time. The considered amphiphilic particle appears to reduce the perturbation of the membrane structure at its equilibrium position inside the peroxidized membrane. This suggests a possibility of antioxidant effect of the nanoparticle.

Distinct toxic interactions of TiO2 nanoparticles with four coexisting organochlorine contaminants on algae.

PubMed

Zhang, Shuai; Deng, Rui; Lin, Daohui; Wu, Fengchang

Engineered nanoparticles are increasingly discharged into the environment. After discharge, these nanoparticles can interact with co-existing organic contaminants, resulting in a phenomena referred to as 'joint toxicity'. This study evaluated joint toxicities of TiO 2 nanoparticles (TiO 2 NPs) with four different (atrazine, hexachlorobenzene, pentachlorobenzene, and 3,3',4,4'-tetrachlorobiphenyl) organochlorine contaminants (OCs) toward algae (Chlorella pyrenoidosa). The potential mechanisms underlying the joint toxicity were discussed, including TiO 2 NPs-OC interactions, effects of TiO 2 NPs and OCs on biophysicochemical properties of algae and effects of TiO 2 NPs and OCs on each other's bioaccumulation in algae. The results indicate that coexposure led to a synergistic effect on the joint toxicity for TiO 2 NPs-atrazine, antagonistic effect for TiO 2 NPs-hexachlorobenzene and TiO 2 NPs-3,3',4,4'-tetrachlorobiphenyl, and an additive effect for TiO 2 NPs-pentachlorobenzene. There was nearly no adsorption of OCs by TiO 2 NPs, and the physicochemical properties of TiO 2 NPs were largely unaltered by the presence of OCs. However, both OCs and NPs affected the biophysicochemical properties of algal cells and thereby influenced the cell surface binding and/or internalization. TiO 2 NPs significantly increased the bioaccumulation of each OC. However, with the exception of atrazine, the bioaccumulation of TiO 2 NPs decreased when used with each OC. The distinct joint toxicity outcomes were a result of the balance between the increased toxicities of OCs (increased bioaccumulations) and the altered toxicity of TiO 2 NPs (bioaccumulation can either increase or decrease). These results can significantly improve our understanding of the potential environmental risks associated with NPs.

The relationship between the Tg depression and the speeding up of physical aging in polystyrene/gold nanocomposites

NASA Astrophysics Data System (ADS)

Boucher, Virginie M.; Cangialosi, Daniele; Alegria, Angel; Colmenero, Juan

2011-03-01

The effect of gold nanoparticles on the segmental dynamics, glass transition (Tg) and physical aging of polystyrene (PS) was studied in PS/Gold nanocomposites samples containing 5 and 15 wt.% of 60 nm spherical gold nanoparticles, surface-treated with thiolated-PS. While the segmental dynamics of PS, as assessed by broadband dielectric spectroscopy (BDS), was found to be unchanged in presence of gold nanoparticles, the calorimetric Tg of PS was shown to decrease with increasing the amount of nanoparticles in the samples. Furthermore, the physical aging of PS, monitored by measuring the enthalpy relaxation below Tg by means of DSC, was shown to speed up with increasing the nanoparticles weight fraction, i.e. the amount of PS/Gold interface in the hybrid material. Thus, the main conclusion of our work is that PS molecular mobility and out-of-equilibrium dynamics are decoupled in these nanocomposites. The significant effect of the amount of PS/Gold interface on both the physical aging rate of PS and the calorimetric Tg depression are quantitatively accounted for by a model based on the diffusion of free volume holes towards polymer interfaces, with a diffusion coefficient depending only on the molecular mobility.

Preparation and Application of LDPE/ZnO Nanocomposites for Extending Shelf Life of Fresh Strawberries

PubMed Central

Mohammadizadeh, Mehri

2015-01-01

Summary Strawberries have a very short post-harvest life mostly due to their relatively high water content, intense metabolic activity and susceptibility to microbial rot. Antimicrobial low-density polyethylene nanocomposite films containing ZnO nanoparticles at different mass fractions were prepared by melt mixing and followed by compression moulding using a hot press machine. Fresh strawberries were packed in nanocomposite films and stored at 4 °C. Their microbial stability, ascorbic acid content and titratable acidity were evaluated after 0, 4, 8, 12 and 16 days of storage. Microbial growth rate was significantly reduced up to 16 days as a result of the use of nanocomposite packaging material containing ZnO nanoparticles. By increasing the ZnO nanoparticle mass fraction to 5%, the antimicrobial activity of the film increased. All packages containing the ZnO nanoparticles kept the microbial load of fresh strawberries below the level that affects shelf life (5 log CFU/g) up to 16 days. The lowest degradation of ascorbic acid content (6.55 mg per 100 g), and loss of acidity (0.68%) were observed in packages containing 3% of ZnO nanoparticles with 10% polyethylene-grafted maleic anhydride. PMID:27904384

Preparation and Application of LDPE/ZnO Nanocomposites for Extending Shelf Life of Fresh Strawberries.

PubMed

Emamifar, Aryou; Mohammadizadeh, Mehri

2015-12-01

Strawberries have a very short post-harvest life mostly due to their relatively high water content, intense metabolic activity and susceptibility to microbial rot. Antimicrobial low-density polyethylene nanocomposite films containing ZnO nanoparticles at different mass fractions were prepared by melt mixing and followed by compression moulding using a hot press machine. Fresh strawberries were packed in nanocomposite films and stored at 4 °C. Their microbial stability, ascorbic acid content and titratable acidity were evaluated after 0, 4, 8, 12 and 16 days of storage. Microbial growth rate was significantly reduced up to 16 days as a result of the use of nanocomposite packaging material containing ZnO nanoparticles. By increasing the ZnO nanoparticle mass fraction to 5%, the antimicrobial activity of the film increased. All packages containing the ZnO nanoparticles kept the microbial load of fresh strawberries below the level that affects shelf life (5 log CFU/g) up to 16 days. The lowest degradation of ascorbic acid content (6.55 mg per 100 g), and loss of acidity (0.68%) were observed in packages containing 3% of ZnO nanoparticles with 10% polyethylene-grafted maleic anhydride.

Gold nanoparticles reduced in situ and dispersed in polymer thin films: optical and thermal properties.

PubMed

Berry, Keith R; Russell, Aaron G; Blake, Phillip A; Keith Roper, D

2012-09-21

Optical and thermal activity of plasmon-active nanoparticles in transparent dielectric media is of growing interest in thermal therapies, photovoltaics and optoelectronic components in which localized surface plasmon resonance (LSPR) could play a significant role. This work compares a new method to embed gold nanoparticles (AuNPs) in dense, composite films with an extension of a previously introduced method. Microscopic and spectroscopic properties of the two films are related to thermal behavior induced via laser excitation of LSPR at 532 nm in the optically transparent dielectric. Gold nanoparticles were incorporated into effectively nonporous 680 μm thick polydimethylsiloxane (PDMS) films by (1) direct addition of organic-coated 16 nm nanoparticles; and (2) reduction of hydrogen tetrachloroaurate (TCA) into AuNPs. Power loss at LSPR excitation frequency and steady-state temperature maxima at 100 mW continuous laser irradiation showed corresponding increases with respect to the mass of gold introduced into the PDMS films by either method. Measured rates of temperature increase were higher for organic-coated NP, but higher gold content was achieved by reducing TCA, which resulted in larger overall temperature changes in reduced AuNP films.

Role of nanoparticle size in self-assemble processes of collagen for tissue engineering application.

PubMed

Vedhanayagam, Mohan; Nidhin, Marimuthu; Duraipandy, Natarajan; Naresh, Niranjan Dhanasekar; Jaganathan, Ganesh; Ranganathan, Mohan; Kiran, Manikantan Syamala; Narayan, Shoba; Nair, Balachandran Unni; Sreeram, Kalarical Janardhanan

2017-06-01

Nanoparticle mediated extracellular matrix may offer new and improved biomaterial to wound healing and tissue engineering applications. However, influence of nanoparticle size in extracellular matrix is still unclear. In this work, we synthesized different size of silver nanoparticles (AgNPs) comprising of 10nm, 35nm and 55nm using nutraceuticals (pectin) as reducing as well as stabilization agents through microwave irradiation method. Synthesized Ag-pectin nanoparticles were assimilated in the self-assemble process of collagen leading to fabricated collagen-Ag-pectin nanoparticle based scaffolds. Physico-chemical properties and biocompatibility of scaffolds were analyzed through FT-IR, SEM, DSC, mechanical strength analyzer, antibacterial activity and MTT assay. Our results suggested that 10nm sized Ag-pectin nanoparticles significantly increased the denaturation temperature (57.83°C) and mechanical strength (0.045MPa) in comparison with native collagen (50.29°C and 0.011MPa). The in vitro biocompatibility assay reveals that, collagen-Ag-pectin nanoparticle based scaffold provided higher antibacterial activity against to Gram positive and Gram negative as well as enhanced cell viability toward keratinocytes. This work opens up a possibility of employing the pectin caged silver nanoparticles to develop collagen-based nanoconstructs for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Thiolated chitosan nanoparticles for enhancing oral absorption of docetaxel: preparation, in vitro and ex vivo evaluation.

PubMed

Saremi, Shahrooz; Atyabi, Fatemeh; Akhlaghi, Seyedeh Parinaz; Ostad, Seyed Nasser; Dinarvand, Rassoul

2011-01-12

The aim of this study was to prepare and evaluate mucoadhesive core-shell nanoparticles based on copolymerization of thiolated chitosan coated on poly methyl methacrylate cores as a carrier for oral delivery of docetaxel. Docetaxel-loaded nanoparticles with various concentrations were prepared via a radical emulsion polymerization method using cerium ammonium nitrate as an initiator. The physicochemical properties of the obtained nanoparticles were characterized by: dynamic light-scattering analysis for their mean size, size distribution, and zeta potential; scanning electron microscopy and transmission electron microscopy for surface morphology; and differential scanning calorimetry analysis for confirmation of molecular dispersity of docetaxel in the nanoparticles. Nanoparticles were spherical with mean diameter below 200 nm, polydispersity of below 0.15, and positive zeta potential values. The entrapment efficiency of the nanoparticles was approximately 90%. In vitro release studies showed a sustained release characteristic for 10 days after a burst release at the beginning. Ex vivo studies showed a significant increase in the transportation of docetaxel from intestinal membrane of rat when formulated as nanoparticles. Cellular uptake of nanoparticles was investigated using fluoresceinamine-loaded nanoparticles. Docetaxel nanoparticles showed a high cytotoxicity effect in the Caco-2 and MCF-7 cell lines after 72 hours. It can be concluded that by combining the advantages of both thiolated polymers and colloidal particles, these nanoparticles can be proposed as a drug carrier system for mucosal delivery of hydrophobic drugs.

Thiolated chitosan nanoparticles for enhancing oral absorption of docetaxel: preparation, in vitro and ex vivo evaluation

PubMed Central

Saremi, Shahrooz; Atyabi, Fatemeh; Akhlaghi, Seyedeh Parinaz; Ostad, Seyed Nasser; Dinarvand, Rassoul

2011-01-01

The aim of this study was to prepare and evaluate mucoadhesive core-shell nanoparticles based on copolymerization of thiolated chitosan coated on poly methyl methacrylate cores as a carrier for oral delivery of docetaxel. Docetaxel-loaded nanoparticles with various concentrations were prepared via a radical emulsion polymerization method using cerium ammonium nitrate as an initiator. The physicochemical properties of the obtained nanoparticles were characterized by: dynamic light-scattering analysis for their mean size, size distribution, and zeta potential; scanning electron microscopy and transmission electron microscopy for surface morphology; and differential scanning calorimetry analysis for confirmation of molecular dispersity of docetaxel in the nanoparticles. Nanoparticles were spherical with mean diameter below 200 nm, polydispersity of below 0.15, and positive zeta potential values. The entrapment efficiency of the nanoparticles was approximately 90%. In vitro release studies showed a sustained release characteristic for 10 days after a burst release at the beginning. Ex vivo studies showed a significant increase in the transportation of docetaxel from intestinal membrane of rat when formulated as nanoparticles. Cellular uptake of nanoparticles was investigated using fluoresceinamine-loaded nanoparticles. Docetaxel nanoparticles showed a high cytotoxicity effect in the Caco-2 and MCF-7 cell lines after 72 hours. It can be concluded that by combining the advantages of both thiolated polymers and colloidal particles, these nanoparticles can be proposed as a drug carrier system for mucosal delivery of hydrophobic drugs. PMID:21289989

Evaluation of zinc oxide nanoparticles toxicity on marine algae chlorella vulgaris through flow cytometric, cytotoxicity and oxidative stress analysis.

PubMed

Suman, T Y; Radhika Rajasree, S R; Kirubagaran, R

2015-03-01

The increasing industrial use of nanomaterials during the last decades poses a potential threat to the environment and in particular to organisms living in the aquatic environment. In the present study, the toxicity of zinc oxide nanoparticles (ZnO NPs) was investigated in Marine algae Chlorella vulgaris (C. vulgaris). High zinc dissociation from ZnONPs, releasing ionic zinc in seawater, is a potential route for zinc assimilation and ZnONPs toxicity. To examine the mechanism of toxicity, C. vulgaris were treated with 50mg/L, 100mg/L, 200mg/L and 300 mg/L ZnO NPs for 24h and 72h. The detailed cytotoxicity assay showed a substantial reduction in the viability dependent on dose and exposure. Further, flow cytometry revealed the significant reduction in C. vulgaris viable cells to higher ZnO NPs. Significant reductions in LDH level were noted for ZnO NPs at 300 mg/L concentration. The activity of antioxidant enzyme superoxide dismutase (SOD) significantly increased in the C. vulgaris exposed to 200mg/L and 300 mg/L ZnO NPs. The content of non-enzymatic antioxidant glutathione (GSH) significantly decreased in the groups with a ZnO NPs concentration of higher than 100mg/L. The level of lipid peroxidation (LPO) was found to increase as the ZnO NPs dose increased. The FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (FESEM and CM). Copyright © 2014 Elsevier Inc. All rights reserved.

Hepatic effects of the clomazone herbicide in both its free form and associated with chitosan-alginate nanoparticles in bullfrog tadpoles.

PubMed

de Oliveira, Cristiane Ronchi; Fraceto, Leonardo Fernandes; Rizzi, Gisele Miglioranza; Salla, Raquel Fernanda; Abdalla, Fábio Camargo; Costa, Monica Jones; Silva-Zacarin, Elaine Cristina Mathias

2016-04-01

The use of agrochemicals in agriculture is intense and most of them could be carried out to aquatic environment. Nevertheless, there are only few studies that assess the effects of these xenobiotics on amphibians. Clomazone is an herbicide widely used in rice fields, where amphibian species live. Thus, those species may be threatened by non-target exposure. However, nanoparticles are being developed to be used as a carrier system for the agrochemicals. Such nanoparticles release the herbicide in a modified way, and are considered to be more efficient and less harmful to the environment. The aim of this study was to comparatively evaluate the effect of clomazone in its free form and associated with nanoparticles, in the liver of bullfrog tadpoles (Lithobates catesbeianus) when submitted to acute exposure for 96 h. According to semi-quantitative analysis, there was an increase in the frequency of melanomacrophage centres, in the accumulation of eosinophils and in lipidosis in the liver of experimental groups exposed to clomazone - in its free form and associated with nanoparticles - in comparison with the control group, and the nanotoxicity of chitosan-alginate nanoparticles. The increase of melanomacrophage centres in all exposed groups was significant (P < 0.0001) in comparison to control group. Therefore, the results of this research have shown that exposure to sublethal doses of the herbicide and nanoparticles triggered hepatic responses. Moreover, these results provided important data about the effect of the clomazone herbicide and organic nanoparticles, which act as carriers of agrochemicals, on the bullfrog tadpole liver. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polymeric nanoparticles of cholesterol-modified glycol chitosan for doxorubicin delivery: preparation and in-vitro and in-vivo characterization.

PubMed

Yu, Jing-Mou; Li, Yong-Jie; Qiu, Li-Yan; Jin, Yi

2009-06-01

Polymeric nanoparticles have been extensively studied as drug carriers. Chitosan and its derivatives have attracted significant attention in this regard but have limited application because of insolubility in biological solution. In this work, we attempted to utilize cholesterol-modified glycol chitosan (CHGC) self-aggregated nanoparticles to increase aqueous solubility, and to reduce side effects and enhance the antitumour efficacy of the anticancer drug doxorubicin. Methods CHGC nanoparticles were loaded with doxorubicin by a dialysis method, and their characteristics were determined by transmission electron microscopy examination, light-scattering study, in-vitro drug-release study, pharmacokinetic study in rats and in-vivo antitumour activity in mice. The resulting doxorubicin-loaded CHGC nanoparticles (DCNs) formed self-assembled aggregates in aqueous medium. From the observation by transmission electron microscopy, DCNs were almost spherical in shape. The mean diameters of these nanoparticles determined by dynamic light scattering were in the range of 237-336 nm as the doxorubicin-loading content increased from 1.73% to 9.36%. In-vitro data indicated that doxorubicin release from DCNs was much faster in phosphate-buffered saline at pH 5.5 than at pH 6.5 and 7.4, and the release rate was dependent on the loading content of doxorubicin in these nanoparticles. It was observed that DCN-16 (drug loaded content: 9.36%) exhibited prolonged circulation time in rat plasma and showed higher antitumour efficacy against S180-bearing mice than free doxorubicin. These results indicated that CHGC nanoparticles had potential as a carrier for insoluble anticancer drugs in cancer therapy.

Synthesis of bio-based nanocomposites for controlled release of antimicrobial agents in food packaging

NASA Astrophysics Data System (ADS)

DeGruson, Min Liu

The utilization of bio-based polymers as packaging materials has attracted great attention in both scientific and industrial areas due to the non-renewable and nondegradable nature of synthetic plastic packaging. Polyhydroxyalkanoate (PHA) is a biobased polymer with excellent film-forming and coating properties, but exhibits brittleness, insufficient gas barrier properties, and poor thermal stability. The overall goal of the project was to develop the polyhydroxyalkanoate-based bio-nanocomposite films modified by antimicrobial agents with improved mechanical and gas barrier properties, along with a controlled release rate of antimicrobial agents for the inhibition of foodborne pathogens and fungi in food. The ability for antimicrobial agents to intercalate into layered double hydroxides depended on the nature of the antimicrobial agents, such as size, spatial structure, and polarity, etc. Benzoate and gallate anions were successfully intercalated into LDH in the present study and different amounts of benzoate anion were loaded into LDH under different reaction conditions. Incorporation of nanoparticles showed no significant effect on mechanical properties of polyhydroxybutyrate (PHB) films, however, significantly increased the tensile strength and elongation at break of polyhydroxybutyrate-co-valerate (PHBV) films. The effects of type and concentration of LDH nanoparticles (unmodified LDH and LDH modified by sodium benzoate and sodium gallate) on structure and properties of PHBV films were then studied. The arrangement of LDH in the bio-nanocomposite matrices ranged from exfoliated to phase-separated depending on the type and concentration of LDH nanoparticles. Intercalated or partially exfoliated structures were obtained using modified LDH, however, only phase-separated structures were formed using unmodified LDH. The mechanical (tensile strength and elongation at break) and thermo-mechanical (storage modulus) properties were significantly improved with low concentrations of nanoparticles incorporated into the polymer. The incorporation of LDH modified by sodium benzoate further improved the mechanical properties in comparison with unmodified LDH, which may be due to the increased compatibility between PHBV and nanoparticles and the larger basal distance between nanolayers after modification. The concentration of benzoate anions in LDH nanoparticles was another factor which affected the properties of PHBV composite films. The PHBV film with 2% modified LDH with 20.9 % w/w of benzoate anions in LDH had the best mechanical and thermomechanical properties. Apparent glass transition temperature increased with the addition of modified LDH but did not change with the addition of unmodified LDH. Moreover, the effect of nanoparticles on thermal properties as well as crystallization of PHBV composites was dependent on the type of nanoparticles. A comparison of mechanical properties and release kinetics of antimicrobial agents directly dispersed in PHBV and modified in LDH and then dispersed in PHBV was made. The results indicated that mechanical properties increased and release rate decreased in the latter case. The release of benzoate and gallate into DI water from PHBV composite films with LDH modified by benzoate and gallate followed pseudo-Fickian behavior fitted with a power law model. The release of benzoate from PHBV composite films with LDH modified by benzoate was also fitted with a Weibull model indicating Fickian behavior in fractal substrate morphologically similar to the percolation cluster. The concentration of modified LDH and the loading of benzoate in modified LDH showed a significant effect on the release kinetics of benzoate. The diffusivities of benzoate at 21 °C ranged from 3.41 to14.97 x 10-16 m 2/s. The slowest release rate was achieved by the PHBV film containing 5 % w/w of modified LDH with medium loading of benzoate (21 % w/w of benzoate) in nanoparticles. The release of gallate from PHBV was much faster than that of benzoate. The effective diffusivity of benzoate increased with increase of temperature and the activation energy Ea for benzoate diffusion was calculated as 66.4 kJ/mol. It will be thus possible to design biodegradable polymeric nanocomposites with a tunable release of active molecules for various applications. (Abstract shortened by UMI.).

BDNF gene delivery mediated by neuron-targeted nanoparticles is neuroprotective in peripheral nerve injury.

PubMed

Lopes, Cátia D F; Gonçalves, Nádia P; Gomes, Carla P; Saraiva, Maria J; Pêgo, Ana P

2017-03-01

Neuron-targeted gene delivery is a promising strategy to treat peripheral neuropathies. Here we propose the use of polymeric nanoparticles based on thiolated trimethyl chitosan (TMCSH) to mediate targeted gene delivery to peripheral neurons upon a peripheral and minimally invasive intramuscular administration. Nanoparticles were grafted with the non-toxic carboxylic fragment of the tetanus neurotoxin (HC) to allow neuron targeting and were explored to deliver a plasmid DNA encoding for the brain-derived neurotrophic factor (BDNF) in a peripheral nerve injury model. The TMCSH-HC/BDNF nanoparticle treatment promoted the release and significant expression of BDNF in neural tissues, which resulted in an enhanced functional recovery after injury as compared to control treatments (vehicle and non-targeted nanoparticles), associated with an improvement in key pro-regenerative events, namely, the increased expression of neurofilament and growth-associated protein GAP-43 in the injured nerves. Moreover, the targeted nanoparticle treatment was correlated with a significantly higher density of myelinated axons in the distal stump of injured nerves, as well as with preservation of unmyelinated axon density as compared with controls and a protective role in injury-denervated muscles, preventing them from denervation. These results highlight the potential of TMCSH-HC nanoparticles as non-viral gene carriers to deliver therapeutic genes into the peripheral neurons and thus, pave the way for their use as an effective therapeutic intervention for peripheral neuropathies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Curcumin-polymeric nanoparticles against colon-26 tumor-bearing mice: cytotoxicity, pharmacokinetic and anticancer efficacy studies.

PubMed

Chaurasia, Sundeep; Chaubey, Pramila; Patel, Ravi R; Kumar, Nagendra; Mishra, Brahmeshwar

2016-01-01

Curcumin (CUR), can inhibit proliferation and induce apoptosis of tumor cells, its extreme insolubility and limited bioavailability restricted its clinical application. An innovative polymeric nanoparticle of CUR has been developed to enhance the bioavailability and anti-cancer efficacy of CUR, in vitro and in vivo. Cationic copolymer Eudragit E 100 was selected as carrier, which can enhance properties of poor bioavailable chemotherapeutic drugs (CUR). The CUR-loaded Eudragit E 100 nanoparticles (CENPs) were prepared by emulsification-diffusion-evaporation method. The in vitro cytotoxicity study of CENPs was carried out using sulphorhodamine B assay. Pharmacokinetic and anti-cancer efficacy of CENPs was investigated in Wister rats as well as colon-26 tumor-bearing mice after oral administration. CENPs showed acceptable particle size and percent entrapment efficiency. In vitro cytotoxicity studies in terms of 50% cell growth inhibition values demonstrated ∼19-fold reduction when treated with CENPs as compared to pure CUR. ∼91-fold increase in Cmax and ∼95-fold increase in AUC0-12h were observed indicating a significant enhancement in the oral bioavailability of CUR when orally administered as CENPs compared to pure CUR. The in vivo anti-cancer study performed with CENPs showed a significant increase in efficacy compared with pure CUR, as observed by tumor volume, body weight and survival rate. The results clearly indicate that the developed polymeric nanoparticles offer a great potential to improve bioavailability and anticancer efficacy of hydrophobic chemotherapeutic drug.

Formation of positively charged gold nanoparticle monolayers on silica sensors.

PubMed

Oćwieja, Magdalena; Maciejewska-Prończuk, Julia; Adamczyk, Zbigniew; Roman, Maciej

2017-09-01

Formation of positively charged gold nanoparticle monolayers on the Si/SiO 2 was studied under in situ conditions using quartz microbalance (QCM). The gold nanoparticles were synthesized in a chemical reduction method using sodium borohydride as reducing agent. Cysteamine hydrochloride was applied to generate a positive surface charge of nanoparticles. The micrographs obtained from transmission electron microscopy (TEM) revealed that the average size of nanoparticles was equal to 12±3nm. The stability of nanoparticle suspensions under controlled pH and ionic strength was determined by dynamic light scattering (DLS). The electrophoretic mobility measurements showed that the zeta potential of nanoparticles was positive, decreasing with ionic strength and pH from 56mV at pH 4.2 and I=10 -4 M to 22mV at pH 8.3 and I=3×10 -3 M. The surface enhanced Raman spectroscopy (SERS) confirmed chemisorption of cysteamine on nanoparticles and the contribution of amine moieties in the generation of nanoparticle charge. The influence of suspension concentration, ionic strength and flow rate on the kinetics of nanoparticle deposition on the sensors was quantitatively determined. It was confirmed that the deposition for the low coverage regime is governed by the bulk mass transfer that results in a linear increase of the coverage with time. The significant increase in the maximum coverage of gold monolayers with ionic strength was interpreted as due to the decreasing range of the electrostatic interactions among deposited particles. Moreover, the hydratation of formed monolayers, their structure and the stability were determined by the comparison of the QCM results with those obtained by AFM and SEM. The experimental data were adequately interpreted in terms of the extended random sequential adsorption (eRSA) model that considers the bulk and surface transfer steps in a rigorous way. The obtained results are useful for a facile fabrication of gold nanoparticle-based biosensors capable to bind target molecules via available amine moieties. Copyright © 2017 Elsevier Inc. All rights reserved.

Nanoparticle mediated micromotor motion

NASA Astrophysics Data System (ADS)

Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y.

2015-03-01

In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ~200 μm s-1. By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ~10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems.In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ~200 μm s-1. By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ~10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems. Electronic supplementary information (ESI) available: Fig. S1-S5 and Video S1-S3. See DOI: 10.1039/c4nr07558g

In vitro toxicity of zinc oxide nanoparticles: a review

NASA Astrophysics Data System (ADS)

Pandurangan, Muthuraman; Kim, Doo Hwan

2015-03-01

The toxic effect of ZnO nanoparticles is due to their solubility. ZnO nanoparticles dissolve in the extracellular region, which in turn increases the intracellular [Zn2+] level. The mechanism for increased intracellular [Zn2+] level and ZnO nanoparticles dissolution in the medium is still unclear. Cytotoxicity, increased oxidative stress, increased intracellular [Ca2+] level, decreased mitochondrial membrane potential, and interleukin-8 productions occur in the BEAS-2B bronchial epithelial cells and A549 alveolar adenocarcinoma cells following the exposure of ZnO nanoparticles. Confluent C2C12 cells are more resistant to ZnO nanoparticles compared to the sparse monolayer. Loss of 3T3-L1 cell viability, membrane leakage, and morphological changes occurs due to exposure of ZnO nanoparticles. ZnO nanoparticle induces cytotoxicity and mitochondrial dysfunction in RKO colon carcinoma cells. The occurrence of apoptosis, increased ROS level, reduced mitochondrial activity and formation of tubular intracellular structures are reported following exposure of ZnO nanoparticles in skin cells. Macrophages, monocytes, and dendritic cells are affected by ZnO nanoparticles. In addition, genotoxicity is also induced. The present review summarizes the literature on in vitro toxicity of ZnO nanoparticles (10-100 nm) on various cell lines.

Folate-conjugated chitosan-polylactide nanoparticles for enhanced intracellular uptake of anticancer drug

NASA Astrophysics Data System (ADS)

Huang, Shengtang; Wan, Ying; Wang, Zheng; Wu, Jiliang

2013-12-01

Chitosan was conjugated with folic acid (FA) and the resulting chitosan derivatives with a FA-substitution degree of around 6 % was used to synthesize FA-conjugated chitosan-polylactide (FA-CH-PLA) copolymers to build a drug carrier with active targeting characteristics for the anticancer drug of paclitaxel (PTX). Selected FA-CH-PLAs with various polylactide percentages of about 40 wt% or lower were employed to fabricate nanoparticles using sodium tripolyphosphate as a crosslinker, and different types of nanoparticles were endued with similar average particle-sizes located in a range between 100 and 200 nm. Certain types of PTX-loaded FA-CH-PLA nanoparticles having encapsulation efficiency of around 90 % and initial load of about 12 % were able to release PTX in a controlled manner with significant regulation by polylactide content in FA-CH-PLAs. Targeting characteristic of achieved nanoparticles was confirmed using FA-receptor-expressed MCF-7 breast cancer cells. The uptake of PTX revealed that optimized FA-CH-PLA nanoparticles with an equivalent PTX-dose of around 1 μg/mL could have more than sixfold increasing abilities to facilitate intracellular paclitaxel accumulation in MCF-7 cells after 24 h treatment as compared to free PTX. At a relatively safe equivalent PTX-dose for normal MCF-10A mammary epithelial cells, the obtained results from Hoechst 33342 staining indicated that optimized PTX-loaded FA-CH-PLA nanoparticles had more than threefold increasing abilities to induce MCF-7 cell apoptosis in comparison to free PTX.

Tailoring Lipid and Polymeric Nanoparticles as siRNA Carriers towards the Blood-Brain Barrier - from Targeting to Safe Administration.

PubMed

Gomes, Maria João; Fernandes, Carlos; Martins, Susana; Borges, Fernanda; Sarmento, Bruno

2017-03-01

Blood-brain barrier is a tightly packed layer of endothelial cells surrounding the brain that acts as the main obstacle for drugs enter the central nervous system (CNS), due to its unique features, as tight junctions and drug efflux systems. Therefore, since the incidence of CNS disorders is increasing worldwide, medical therapeutics need to be improved. Consequently, aiming to surpass blood-brain barrier and overcome CNS disabilities, silencing P-glycoprotein as a drug efflux transporter at brain endothelial cells through siRNA is considered a promising approach. For siRNA enzymatic protection and efficient delivery to its target, two different nanoparticles platforms, solid lipid (SLN) and poly-lactic-co-glycolic (PLGA) nanoparticles were used in this study. Polymeric PLGA nanoparticles were around 115 nm in size and had 50 % of siRNA association efficiency, while SLN presented 150 nm and association efficiency close to 52 %. Their surface was functionalized with a peptide-binding transferrin receptor, in a site-oriented manner confirmed by NMR, and their targeting ability against human brain endothelial cells was successfully demonstrated by fluorescence microscopy and flow cytometry. The interaction of modified nanoparticles with brain endothelial cells increased 3-fold compared to non-modified lipid nanoparticles, and 4-fold compared to non-modified PLGA nanoparticles, respectively. These nanosystems, which were also demonstrated to be safe for human brain endothelial cells, without significant cytotoxicity, bring a new hopeful breath to the future of brain diseases therapies.

Effect of Multiple Reflow Cycles and Al2O3 Nanoparticles Reinforcement on Performance of SAC305 Lead-Free Solder Alloy

NASA Astrophysics Data System (ADS)

Tikale, Sanjay; Prabhu, K. Narayan

2018-05-01

The effect of Al2O3 nanoparticles reinforcement on melting behavior, microstructure evolution at the interface and joint shear strength of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder alloy subjected to multiple reflow cycles was investigated. The reinforced SAC305 solder alloy compositions were prepared by adding Al2O3 nanoparticles in different weight fractions (0.05, 0.1, 0.3 and 0.5 wt.%) through mechanical dispersion. Cu/solder/Cu micro-lap-shear solder joint specimens were used to assess the shear strength of the solder joint. Differential scanning calorimetry was used to investigate the melting behavior of SAC305 solder nanocomposites. The solder joint interfacial microstructure was studied using scanning electron microscopy. The results showed that the increase in melting temperature (T L) and melting temperature range of the SAC305 solder alloy by addition of Al2O3 nanoparticles were not significant. In comparison with unreinforced SAC305 solder alloy, the reinforcement of 0.05-0.5 wt.% of Al2O3 nanoparticles improved the solder wettability. The addition of nanoparticles in minor quantity effectively suppressed the Cu6Sn5 IMC growth, improved the solder joint shear strength and ductility under multiple reflow cycles. However, the improvement in solder properties was less pronounced on increasing the nanoparticle content above 0.1 wt.% of the solder alloy.

Improved delivery of magnetic nanoparticles with chemotherapy cancer treatment

NASA Astrophysics Data System (ADS)

Petryk, Alicia A.; Giustini, Andrew J.; Gottesman, Rachel E.; Hoopes, P. Jack

2013-02-01

Most nanoparticle-based cancer therapeutic strategies seek to develop an effective individual cancer cell or metastatic tumor treatment. Critical to the success of these therapies is to direct as much of the agent as possible to the targeted tissue while avoiding unacceptable normal tissue complications. In this light, three different cisplatinum/magnetic nanoparticle (mNP) administration regimens were investigated. The most important finding suggests that clinically relevant doses of cisplatinum result in a significant increase in the tumor uptake of systemically delivered mNP. This enhancement of mNP tumor uptake creates the potential for an even greater therapeutic ratio through the addition of mNP based, intracellular hyperthermia.

Improvement of photon correlation spectroscopy method for measuring nanoparticle size by using attenuated total reflectance.

PubMed

Krishtop, Victor; Doronin, Ivan; Okishev, Konstantin

2012-11-05

Photon correlation spectroscopy is an effective method for measuring nanoparticle sizes and has several advantages over alternative methods. However, this method suffers from a disadvantage in that its measuring accuracy reduces in the presence of convective flows of fluid containing nanoparticles. In this paper, we propose a scheme based on attenuated total reflectance in order to reduce the influence of convection currents. The autocorrelation function for the light-scattering intensity was found for this case, and it was shown that this method afforded a significant decrease in the time required to measure the particle sizes and an increase in the measuring accuracy.

TiO2 nanoparticle induced space charge decay in thermal aged transformer oil

NASA Astrophysics Data System (ADS)

Lv, Yuzhen; Du, Yuefan; Li, Chengrong; Qi, Bo; Zhong, Yuxiang; Chen, Mutian

2013-04-01

TiO2 nanoparticle with good dispersibility and stability in transformer oil was prepared and used to modify insulating property of aged oil. It was found that space charge decay rate in the modified aged oil can be significantly enhanced to 1.57 times of that in the aged oil at first 8 s after polarization voltage was removed. The results of trap characteristics reveal that the modification of nanoparticle can not only greatly lower the shallow trap energy level in the aged oil but also increase the trap density, resulting in improved charge transportation via trapping and de-trapping process in shallower traps.

Compressibility of porous TiO2 nanoparticle coating on paperboard

PubMed Central

2013-01-01

Compressibility of liquid flame spray-deposited porous TiO2 nanoparticle coating was studied on paperboard samples using a traditional calendering technique in which the paperboard is compressed between a metal and polymer roll. Surface superhydrophobicity is lost due to a smoothening effect when the number of successive calendering cycles is increased. Field emission scanning electron microscope surface and cross‒sectional images support the atomic force microscope roughness analysis that shows a significant compressibility of the deposited TiO2 nanoparticle coating with decrease in the surface roughness and nanoscale porosity under external pressure. PACS 61.46.-w; 68.08.Bc; 81.07.-b PMID:24160373

Insulin-loaded pH-sensitive hyaluronic acid nanoparticles enhance transcellular delivery.

PubMed

Han, Lina; Zhao, Yuefang; Yin, Lifang; Li, Ruiming; Liang, Yang; Huang, Huan; Pan, Shirong; Wu, Chuanbin; Feng, Min

2012-09-01

In the present study, we developed novel insulin-loaded hyaluronic acid (HA) nanoparticles for insulin delivery. The insulin-loaded HA nanoparticles were prepared by reverse-emulsion-freeze-drying method. This method led to a homogenous population of small HA nanoparticles with average size of 182.2 nm and achieved high insulin entrapment efficiencies (approximately 95%). The pH-sensitive HA nanoparticles as an oral delivery carrier showed advantages in protecting insulin against the strongly acidic environment of the stomach, and not destroying the junction integrity of epithelial cells which promise long-term safety for chronic insulin treatment. The results of transport experiments suggested that insulin-loaded HA nanoparticles were transported across Caco-2 cell monolayers mainly via transcellular pathway and their apparent permeability coefficient from apical to basolateral had more than twofold increase compared with insulin solution. The efflux ratio of P (app) (B to A) to P (app) (A to B) less than 1 demonstrated that HA nanoparticle-mediated transport of insulin across Caco-2 cell monolayers underwent active transport. The results of permeability through the rat small intestine confirmed that HA nanoparticles significantly enhanced insulin transport through the duodenum and ileum. Diabetic rats treated with oral insulin-loaded HA nanoparticles also showed stronger hypoglycemic effects than insulin solution. Therefore, these HA nanoparticles could be a promising candidate for oral insulin delivery.

Nanoparticle mediated micromotor motion.

PubMed

Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y

2015-03-21

In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ∼200 μm s(-1). By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ∼10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems.

Improvement of In Vitro and In Vivo Antileishmanial Activities of 2′,6′-Dihydroxy-4′-Methoxychalcone by Entrapment in Poly(d,l-Lactide) Nanoparticles

PubMed Central

Torres-Santos, Eduardo Caio; Rodrigues, José M.; Moreira, Davyson L.; Kaplan, Maria Auxiliadora C.; Rossi-Bergmann, Bartira

1999-01-01

The inhibition of intracellular Leishmania amazonensis growth by 2′,6′-dihydroxy-4′-methoxychalcone (DMC) isolated from Piper aduncum was further enhanced after encapsulation of DMC in polymeric nanoparticles. Encapsulated DMC also showed increased antileishmanial activity in infected BALB/c mice, as evidenced by significantly smaller lesions and fewer parasites in the lesions. PMID:10390243

Fabrication of an anti-viral air filter with SiO₂-Ag nanoparticles and performance evaluation in a continuous airflow condition.

PubMed

Joe, Yun Haeng; Woo, Kyoungja; Hwang, Jungho

2014-09-15

In this study, SiO2 nanoparticles surface coated with Ag nanoparticles (SA particles) were fabricated to coat a medium air filter. The pressure drop, filtration efficiency, and anti-viral ability of the filter were evaluated against aerosolized bacteriophage MS2 in a continuous air flow condition. A mathematical approach was developed to measure the anti-viral ability of the filter with various virus deposition times. Moreover, two quality factors based on the anti-viral ability of the filter, and a traditional quality factor based on filtration efficiency, were calculated. The filtration efficiency and pressure drop increased with decreasing media velocity and with increasing SA particle coating level. The anti-viral efficiency also increased with increasing SA particle coating level, and decreased by with increasing virus deposition time. Consequently, SA particle coating on a filter does not have significant effects on filtration quality, and there is an optimal coating level to produce the highest anti-viral quality. Copyright © 2014 Elsevier B.V. All rights reserved.

Degradation of 2,4-D in soils by Fe₃O₄ nanoparticles combined with stimulating indigenous microbes.

PubMed

Fang, Guodong; Si, Youbin; Tian, Chao; Zhang, Gangya; Zhou, Dongmei

2012-03-01

Degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) in soils by Fe₃O₄ nanoparticles combined with soil indigenous microbes was investigated, and the effects of Fe₃O₄ nanoparticles on soil microbial populations and enzyme activities were also studied. The soils contaminated with 2,4-D were treated with Fe₃O₄ nanoparticles. The microbial populations and enzyme activities were analyzed by dilution plate method and chemical assay, respectively, and the concentration of 2,4-D in soil was determined by high-performance liquid chromatography (HPLC). The results indicated that Fe₃O₄ nanoparticles combined with soil indigenous microbes led to a higher degradation efficiency of 2,4-D than the treatments with Fe₃O₄ nanoparticles or indigenous microbes alone. The degradation of 2,4-D in soils followed the pseudo first-order kinetic. The half-lives of 2,4-D degradation (DT₅₀) of the combined treatments were 0.9, 1.9 and 3.1 days in a Red soil, Vertisol and Alfisol, respectively, which implied that the DT₅₀ of the combination treatments were significantly shorter than that of the treatments Fe₃O₄ nanoparticles or indigenous microbes alone. The effects of Fe₃O₄ nanoparticles on soil microbial populations and enzyme activities were also investigated and compared with the α-Fe₂O₃ nanoparticles. The results suggested that the α-Fe₂O₃ nanoparticles had only comparatively small effects on degradation of 2,4-D in soils, while the Fe₃O₄ nanoparticles not only degraded 2,4-D in soils but also increased the soil microbial populations and enzyme activities; the maximum increase in enzyme activities were 67.8% (amylase), 53.8% (acid phosphatase), 26.5% (catalase) and 38.0% (urease), compared with the untreated soil. Moreover, the introduction of Fe₃O₄ nanoparticles at the different dosage resulted in a variable degradation efficiency of 2,4-D in soil. The method of combining Fe₃O₄ nanoparticles with indigenous soil microbes may offer great benefits for the application of nanotechnology in remediation of herbicide contaminated soil.

Production of pure indinavir free base nanoparticles by a supercritical anti-solvent (SAS) method.

PubMed

Imperiale, Julieta C; Bevilacqua, Gabriela; Rosa, Paulo de Tarso Vieira E; Sosnik, Alejandro

2014-12-01

This work investigated the production of pure indinavir free base nanoparticles by a supercritical anti-solvent method to improve the drug dissolution in intestine-like medium. To increase the dissolution of the drug by means of a supercritical fluid processing method. Acetone was used as solvent and supercritical CO2 as antisolvent. Products were characterized by dynamic light scattering (size, size distribution), scanning electron microscopy (morphology), differential scanning calorimetry (thermal behaviour) and X-rays diffraction (crystallinity). Processed indinavir resulted in particles of significantly smaller size than the original drug. Particles showed at least one dimension at the nanometer scale with needle or rod-like morphology. Results of X-rays powder diffraction suggested the formation of a mixture of polymorphs. Differential scanning calorimetry analysis showed a main melting endotherm at 152 °C. Less prominent transitions due to the presence of small amounts of bound water (in the raw drug) or an unstable polymorph (in processed IDV) were also visible. Finally, drug particle size reduction significantly increased the dissolution rate with respect to the raw drug. Conversely, the slight increase of the intrinsic solubility of the nanoparticles was not significant. A supercritical anti-solvent method enabled the nanonization of indinavir free base in one single step with high yield. The processing led to faster dissolution that would improve the oral bioavailability of the drug.

A Preliminary Assessment of Silver Nanoparticle Inhibition of Monkeypox Virus Plaque Formation

NASA Astrophysics Data System (ADS)

Rogers, James V.; Parkinson, Christopher V.; Choi, Young W.; Speshock, Janice L.; Hussain, Saber M.

2008-04-01

The use of nanotechnology and nanomaterials in medical research is growing. Silver-containing nanoparticles have previously demonstrated antimicrobial efficacy against bacteria and viral particles. This preliminary study utilized an in vitro approach to evaluate the ability of silver-based nanoparticles to inhibit infectivity of the biological select agent, monkeypox virus (MPV). Nanoparticles (10 80 nm, with or without polysaccharide coating), or silver nitrate (AgNO3) at concentrations of 100, 50, 25, and 12.5 μg/mL were evaluated for efficacy using a plaque reduction assay. Both Ag-PS-25 (polysaccharide-coated, 25 nm) and Ag-NP-55 (non-coated, 55 nm) exhibited a significant ( P ≤ 0.05) dose-dependent effect of test compound concentration on the mean number of plaque-forming units (PFU). All concentrations of silver nitrate (except 100 μg/mL) and Ag-PS-10 promoted significant ( P ≤ 0.05) decreases in the number of observed PFU compared to untreated controls. Some nanoparticle treatments led to increased MPV PFU ranging from 1.04- to 1.8-fold above controls. No cytotoxicity (Vero cell monolayer sloughing) was caused by any test compound, except 100 μg/mL AgNO3. These results demonstrate that silver-based nanoparticles of approximately 10 nm inhibit MPV infection in vitro, supporting their potential use as an anti-viral therapeutic.

pH-Responsive Nanoparticle Vaccines for Dual-Delivery of Antigens and Immunostimulatory Oligonucleotides

PubMed Central

Wilson, John T.; Keller, Salka; Manganiello, Matthew J.; Cheng, Connie; Lee, Chen-Chang; Opara, Chinonso; Convertine, Anthony; Stayton, Patrick S.

2013-01-01

Protein subunit vaccines offer important potential advantages over live vaccine vectors, but generally elicit weaker and shorter-lived cellular immune responses. Here we investigate the use of pH-responsive, endosomolytic polymer nanoparticles that were originally developed for RNA delivery as vaccine delivery vehicles for enhancing cellular and humoral immune responses. Micellar nanoparticles were assembled from amphiphilic diblock copolymers composed of an ampholytic core-forming block and a re-designed polycationic corona block doped with thiol-reactive pyridyl disulfide groups to enable dual-delivery of antigens and immunostimulatory CpG oligodeoxynucleotide (CpG ODN) adjuvants. Polymers assembled into 23 nm particles with simultaneous packaging of CpG ODN and a thiolated protein antigen, ovalbumin (ova). Conjugation of ova to nanoparticles significantly enhanced antigen cross-presentation in vitro relative to free ova or an unconjugated, physical mixture of the parent compounds. Subcutaneous vaccination of mice with ova-nanoparticle conjugates elicited a significantly higher CD8+ T cell response (0.5% IFN-ɣ+ of CD8+) compared to mice vaccinated with free ova or a physical mixture of the two components. Significantly, immunization with ova-nanoparticle conjugates electrostatically complexed with CpG ODN (dual-delivery) enhanced CD8+ T cell responses (3.4% IFN-ɣ+ of CD8+) 7-, 18-, and 8-fold relative to immunization with conjugates, ova administered with free CpG, or a formulation containing free ova and CpG complexed to micelles, respectively. Similarly, dual-delivery carriers significantly increased CD4+IFN-ɣ+ (Th1) responses, and elicited a balanced IgG1/IgG2c antibody response. Intradermal administration further augmented cellular immune responses, with dual-delivery carriers inducing ~7% antigen-specific CD8+ T cells. This work demonstrates the ability of pH-responsive, endosomolytic nanoparticles to actively promote antigen cross-presentation and augment cellular and humoral immune responses via dual-delivery of protein antigens and CpG ODN. Hence, pH-responsive polymeric nanoparticles offer promise as a delivery platform for protein subunit vaccines. PMID:23590591

Preparation of carboplatin-Fe@C-loaded chitosan nanoparticles and study on hyperthermia combined with pharmacotherapy for liver cancer.

PubMed

Li, Fu-rong; Yan, Wen-hui; Guo, Yue-hua; Qi, Hui; Zhou, Han-xin

2009-08-01

Magnetic fluid hyperthermia is a kind of technology for treating tumors based on nanotechnology. It is suitable to various types of tumors. The purpose of this study was to prepare carboplatin-Fe@C-loaded chitosan nanoparticles with Fe@C as a magnetic core and to investigate efficacy of hyperthermia combined with chemotherapy for transplanted liver cancer in rats. Fe@C nanopowder was treated with dilute hydrochloric acid to prepare Fe@C nanocage. Carboplatin-Fe@C-loaded chitosan nanoparticles were prepared by reverse microemulsion method with the nanocages as the magnetic cores, chitosan as the matrix. The shape, size, drug-loading rate, and in vitro cumulative release of the nanoparticles were observed and heat product under high frequency alternating electromagnetic field in vitro was explored. Eighty rats with transplanted liver cancer were randomly divided into 4 groups (group A: control group, group B: free carboplatin group, group C: nanoparticles with static magnetic field group, and group D: nanoparticles with static field and alternating magnetic field). Drug was injected into the hepatic artery. The therapeutic effect of hyperthermia combined with chemotherapy for tumor, toxicity and rat survival time were observed. Carboplatin-Fe@C-loaded chitosan nanoparticles were spherical in shape with an average size of (207 +/- 21) nm and high saturation magnetization. The drug-loading rate of the nanoparticles was 11.0 +/- 1.1%. The cumulative release percentage of carboplatin-Fe@C-loaded chitosan nanoparticles in vitro at different point time phase of 24 h, 48 h, 72 h, 96 h and 120 h were 51%, 68%, 80%, 87% and 91%, respectively. With an increase in carboplatin-Fe@C-loaded chitosan nanoparticle concentration and magnetic field strength, the heating rate and constant temperature of carboplatin-Fe@C-loaded chitosan nanoparticles dispersed in physiological saline were increased in an alternating magnetic field. In vivo experiments showed that after particle injection, tumor temperature reached 42.6 degrees +/- 0.2 degrees C within 10 min in the alternating magnetic field; and the temperatures in the right hepatic lobes and the rectum were significantly lower than in the tumor and the constant temperature could last up to 30 min. The inhibition ratio of tumor weight in group D was significantly enhanced, no obviously toxic and side-effect occurred and survival time was prolonged. Carboplatin-Fe@C-loaded chitosan nanoparticles possess good magnetic targeting and heat production properties. They can target liver cancer tissue by static magnetic field, and with the application of alternating magnetic field, effectively raise tumor tissue temperature and facilitate tumor apoptosis. The combination of chemotherapy and magnetic materials into nanoparticles as described herein demonstrates promising efficacy.

Biodegradable bisphosphonate nanoparticles for imaging and therapeutic applications in osteosarcoma

NASA Astrophysics Data System (ADS)

Rudnick-Glick, S.; Corem-Salkmon, E.; Grinberg, I.; Gluz, E.; Margel, S.

2015-08-01

Osteosarcoma (OS) is amongst the most commonly diagnosed bone tumors occurring in adolescence, young adults and adults over the age of 65. Current treatment is based on a combination of surgery and chemotherapy. Chemotherapy has improved the survival rate, however it is associated with severe side effects due to the use of high dosages, nonspecific uptake and poor bone blood supply. At present bisphosphonates (BP) are widely used in the treatment of bone disorders including OS. We have engineered a unique biodegradable BP nanoparticle that possesses a dual functionality: 1) covalent attachment of a dye (e.g., NIR dye) or drug to the nanoparticles through the primary amine groups on the surface of the nanoparticle; 2) chelation to the bone mineral hydroxyapatite through the BP on the surface of the nanoparticle. Due to a high concentration of PEG in the BP nanoparticles they possess a relatively long plasma half-life time. Therefore, the nanoparticle has potential for use both in diagnosis and therapy of OS. Doxorubicin was conjugated to the free amine on the surface of the BP nanoparticles. In vitro experiments on osteosarcoma cells demonstrated that the doxorubicin-conjugated BP nanoparticles possess a higher efficacy than the free doxorubicin. Further investigation in vivo in a chicken embryo model confirmed that the doxorubicin-conjugated nanoparticle was significantly more effective in inhibiting tumor growth compared to free doxorubicin at a similar concentration. Additionally, we have shown that these BP nanoparticles preferentially target OS tumor tissue, thus increasing anti-cancer drug bioavailability at targeted site.

Effects of Fe3O4 Magnetic Nanoparticles on the Thermoelectric Properties of Heavy-Fermion YbAl3 Materials

NASA Astrophysics Data System (ADS)

He, Danqi; Mu, Xin; Zhou, Hongyu; Li, Cuncheng; Ma, Shifang; Ji, Pengxia; Hou, Weikang; Wei, Ping; Zhu, Wanting; Nie, Xiaolei; Zhao, Wenyu

2018-06-01

The magnetic nanocomposite thermoelectric materials xFe3O4/YbAl3 ( x = 0%, 0.3%, 0.6%, 1.0%, and 1.5%) have been prepared by the combination of ultrasonic dispersion and spark plasma sintering process. The nanocomposites retain good chemical stability in the presence of the second-phase Fe3O4. The second-phase Fe3O4 magnetic nanoparticles are distributed on the interfaces and boundaries of the matrix. The x dependences of thermoelectric properties indicate that Fe3O4 magnetic nanoparticles can significantly decrease the thermal conductivity and electrical conductivity. The magnetic nanoparticles embedded in YbAl3 matrix are not only the phonon scattering centers of nanostructures, but also the electron scattering centers due to the Kondo-like effect between the magnetic moment of Fe3O4 nanoparticles and the spin of electrons. The ZT values of the composites are first increased in the x range 0%-1.0% and then decreased when x > 1.0%. The highest ZT value reaches 0.3 at 300 K for the nanocomposite with x = 1.0%. Our work demonstrates that the Fe3O4 magnetic nanoparticles can greatly increase the thermoelectric performance of heavy-fermion YbAl3 thermoelectric materials through simultaneously scattering electrons and phonons.

Effect of cryoprotectants on the porosity and stability of insulin-loaded PLGA nanoparticles after freeze-drying

PubMed Central

Fonte, Pedro; Soares, Sandra; Costa, Ana; Andrade, José Carlos; Seabra, Vítor; Reis, Salette; Sarmento, Bruno

2012-01-01

PLGA nanoparticles are useful to protect and deliver proteins in a localized or targeted manner, with a long-term systemic delivery pattern intended to last for a period of time, depending on polymer bioerosion and biodegradability. However, the principal concern regarding these carriers is the hydrolytic instability of polymer in aqueous suspension. Freeze-drying is a commonly used method to stabilize nanoparticles, and cryoprotectants may be also used, to even increase its physical stability. The aim of the present work was to analyze the influence of cryoprotectants on nanoparticle stability and porosity after freeze-drying, which may influence protein release and stability. It was verified that freeze-drying significantly increased the number of pores on PLGA-NP surface, being more evident when cryoprotectants are added. The presence of pores is important in a lyophilizate to facilitate its reconstitution in water, although this may have consequences to protein release and stability. The release profile of insulin encapsulated into PLGA-NP showed an initial burst in the first 2 h and a sustained release up to 48 h. After nanoparticles freeze-drying the insulin release increased about 18% in the first 2 h due to the formation of pores, maintaining a sustained release during time. After freeze-drying with cryoprotectants, the amount of insulin released was higher for trehalose and lower for sucrose, glucose, fructose and sorbitol comparatively to freeze-dried PLGA-NP with no cryoprotectant added. Besides the porosity, the ability of cryoprotectants to be adsorbed on the nanoparticles surface may also play an important role on insulin release and stability. PMID:23507897

Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

NASA Astrophysics Data System (ADS)

Kumar, Sachin; Chatterjee, Kaushik

2015-01-01

The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05060f

Thermal stability of supported gold nanoparticles

NASA Astrophysics Data System (ADS)

Turba, Timothy Fredrick

Nanoparticle gold is of interest for a wide array of applications including catalysis, gas sensing, and light absorption for color filters and optical switches. Many of these applications are dependent upon the particles having sizes <5nm. In this paper, the thermal stability of nanoparticle gold is evaluated. Unsupported gold nanoparticles can grow (and in some cases double their size) even at room temperature. An important approach to stabilizing gold nanoparticles is through an interaction with a suitable substrate support material. Semiconductor substrates such as GaN are important supports for gold nanoparticles for applications such as sensors, but GaN does not provide a significant stabilizing effect at high temperatures. This paper covers a number of different substrate materials and in particular shows that for some substrates, such as SiO2, gold nanoparticles can be stable at temperatures up to 500°C, which is significantly above the Tammann temperature for bulk gold (395°C). In this dissertation, gold nanoparticles are shown to have complete stability on aluminum-supported silica nanosprings at 550°C in air. This stability window is one of the highest reported for nanoparticle gold and potentially enables a number of applications for this highly active catalyst. X-ray photoelectron spectroscopy measurements were performed before and after heating to 550°C to determine the nature of the interaction between gold and SiO2. A 1.2 eV drop in gold 4f binding energy after heating signified a shift to anionic gold particles (i.e., Au delta-) indicative of strong bonds to oxygen vacancies with neighboring Sidelta+ atoms. Heating in hydrogen at 550°C resulted in a binding energy decrease of 0.4 eV due to an increased fraction of particles with decreased coordination numbers (i.e., more atoms at edges and corners). Lastly, heating gold nanoparticles in an atmosphere of 10% relative humidity at 550°C resulted in apparent encapsulation of the gold.

Functionalized rare earth-doped nanoparticles for breast cancer nanodiagnostic using fluorescence and CT imaging.

PubMed

Jain, Akhil; Fournier, Pierrick G J; Mendoza-Lavaniegos, Vladimir; Sengar, Prakhar; Guerra-Olvera, Fernando M; Iñiguez, Enrique; Kretzschmar, Thomas G; Hirata, Gustavo A; Juárez, Patricia

2018-03-22

Breast cancer is the second leading cause of cancer death among women and represents 14% of death in women around the world. The standard diagnosis method for breast tumor is mammography, which is often related with false-negative results leading to therapeutic delays and contributing indirectly to the development of metastasis. Therefore, the development of new tools that can detect breast cancer is an urgent need to reduce mortality in women. Here, we have developed Gd 2 O 3 :Eu 3+ nanoparticles functionalized with folic acid (FA), for breast cancer detection. Gd 2 O 3 :Eu 3+ nanoparticles were synthesized by sucrose assisted combustion synthesis and functionalized with FA using EDC-NHS coupling. The FA-conjugated Gd 2 O 3 :Eu 3+ nanoparticles exhibit strong red emission at 613 nm with a quantum yield of ~ 35%. In vitro cytotoxicity studies demonstrated that the nanoparticles had a negligible cytotoxic effect on normal 293T and T-47D breast cancer cells. Cellular uptake analysis showed significantly higher internalization of FA-conjugated RE nanoparticles into T-47D cells (Folr hi ) compared to MDA-MB-231 breast cancer cells (Folr lo ). In vivo confocal and CT imaging studies indicated that FA-conjugated Gd 2 O 3 :Eu 3+ nanoparticles accumulated more efficiently in T-47D tumor xenograft compared to the MDA-MB-231 tumor. Moreover, we found that FA-conjugated Gd 2 O 3 :Eu 3+ nanoparticles were well tolerated at high doses (300 mg/kg) in CD1 mice after an intravenous injection. Thus, FA-conjugated Gd 2 O 3 :Eu 3+ nanoparticles have great potential to detect breast cancer. Our findings provide significant evidence that could permit the future clinical application of FA-conjugated Gd 2 O 3 :Eu 3+ nanoparticles alone or in combination with the current detection methods to increase its sensitivity and precision.

Nanoparticle Inhalation Impairs Coronary Microvascular Reactivity via a Local Reactive Oxygen Species-Dependent Mechanism

PubMed Central

LeBlanc, A. J.; Moseley, A. M.; Chen, B. T.; Frazer, D.; Castranova, V.

2010-01-01

We have shown that nanoparticle inhalation impairs endothelium-dependent vasodilation in coronary arterioles. It is unknown whether local reactive oxygen species (ROS) contribute to this effect. Rats were exposed to TiO2 nanoparticles via inhalation to produce a pulmonary deposition of 10 µg. Coronary arterioles were isolated from the left anterior descending artery distribution, and responses to acetylcholine, arachidonic acid, and U46619 were assessed. Contributions of nitric oxide synthase and prostaglandin were assessed via competitive inhibition with NG-Monomethyl-L-Arginine (L-NMMA) and indomethacin. Microvascular wall ROS were quantified via dihydroethidium (DHE) fluorescence. Coronary arterioles from rats exposed to nano-TiO2 exhibited an attenuated vasodilator response to ACh, and this coincided with a 45% increase in DHE fluorescence. Coincubation with 2,2,6,6-tetramethylpiperidine-N-oxyl and catalase ameliorated impairments in ACh-induced vasodilation from nanoparticle exposed rats. Incubation with either L-NMMA or indomethacin significantly attenuated Ach-induced vasodilation in sham-control rats, but had no effect in rats exposed to nano-TiO2. Arachidonic acid induced vasoconstriction in coronary arterioles from rats exposed to nano-TiO2, but dilated arterioles from sham-control rats. These results suggest that nanoparticle exposure significantly impairs endothelium-dependent vasoreactivity in coronary arterioles, and this may be due in large part to increases in microvascular ROS. Furthermore, altered prostanoid formation may also contribute to this dysfunction. Such disturbances in coronary microvascular function may contribute to the cardiac events associated with exposure to particles in this size range. PMID:20033351

Plasmon-enhanced solar energy conversion in organic bulk heterojunction photovoltaics

NASA Astrophysics Data System (ADS)

Morfa, Anthony J.; Rowlen, Kathy L.; Reilly, Thomas H.; Romero, Manuel J.; van de Lagemaat, Jao

2008-01-01

Plasmon-active silver nanoparticle layers were included in solution-processed bulk-heterojunction solar cells. Nanoparticle layers were fabricated using vapor-phase deposition on indium tin oxide electrodes. Owing to the increase in optical electrical field inside the photoactive layer, the inclusion of such particle films lead to increased optical absorption and consequently increased photoconversion at solar-conversion relevant wavelengths. The resulting solar energy conversion efficiency for a bulk heterojunction photovoltaic device of poly(3-hexylthiophene)/[6,6]-phenyl C61 butyric acid methyl ester was found to increase from 1.3%±0.2% to 2.2%±0.1% for devices employing thin plasmon-active layers. Based on six measurements, the improvement factor of 1.7 was demonstrated to be statistically significant.

Evaluation of zinc oxide nanoparticle toxicity in sludge products applied to agricultural soil using multispecies soil systems.

PubMed

Fernández, María Dolores; Alonso-Blázquez, María Nieves; García-Gómez, Concepción; Babin, Mar

2014-11-01

To study the environmental impact of nanoparticles, the sludges of wastewater (WWTS) and water treatment (WTS) plants enriched with ZnO nanoparticles were added to agricultural soil, and the toxic effects of the nanoparticles were studied using a microcosm system based on the soil. The WWTS treated soils were characterised by statistically significant decreases (p<0.05) in Vicia sativa germination at the lowest (76.2%) and medium (95.2%) application rates, decreases in the fresh biomass for Triticum aestivum (19.5%), Raphanus sativus (64.1%), V. sativa (37.4%) and Eisenia fetida (33.6%) at the highest application rate and a dose-related significant increase (p<0.05) in earthworm mortality. In WTS amended soils, significant reductions (p<0.05) of the fresh biomass (17.2%) and the chlorophyll index (24.4%) for T. aestivum and the fresh biomass for R. sativus (31.4%) were only recorded at the highest application doses. In addition, the soil phosphatase enzymatic activity decreased significantly (p<0.05) in both WWTS (dose related) and WTS treatments. For water organisms, a slight inhibition of the growth of Chlorella vulgaris was observed (WWTS treated soils), along with statistically significant dose-related inhibition responses on total glutathione cell content, and statistically significant dose-related induction responses on the glutathione S-transferase enzyme activity and the reactive oxygen species generation on the RTG-2 fish cell line. Copyright © 2014 Elsevier B.V. All rights reserved.

PLGA nanoparticles containing various anticancer agents and tumour delivery by EPR effect.

PubMed

Acharya, Sarbari; Sahoo, Sanjeeb K

2011-03-18

As mortality due to cancer continues to rise, advances in nanotechnology have significantly become an effective approach for achieving efficient drug targeting to tumour tissues by circumventing all the shortcomings of conventional chemotherapy. During the past decade, the importance of polymeric drug-delivery systems in oncology has grown exponentially. In this context, poly(lactic-co-glycolic acid) (PLGA) is a widely used polymer for fabricating 'nanoparticles' because of biocompatibility, long-standing track record in biomedical applications and well-documented utility for sustained drug release, and hence has been the centre of focus for developing drug-loaded nanoparticles for cancer therapy. Such PLGA nanoparticles have also been used to develop proteins and peptides for nanomedicine, and nanovaccines, as well as a nanoparticle-based drug- and gene-delivery system for cancer therapy, and nanoantigens and growth factors. These drug-loaded nanoparticles extravasate through the tumour vasculature, delivering their payload into the cells by the enhanced permeability and retention (EPR) effect, thereby increasing their therapeutic effect. Ongoing research about drug-loaded nanoparticles and their delivery by the EPR effect to the tumour tissues has been elucidated in this review with clarity. Copyright © 2010 Elsevier B.V. All rights reserved.

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

NASA Astrophysics Data System (ADS)

Strobel, L. A.; Hild, N.; Mohn, D.; Stark, W. J.; Hoppe, A.; Gbureck, U.; Horch, R. E.; Kneser, U.; Boccaccini, A. R.

2013-07-01

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30-35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 μg/cm² (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 μg/cm², Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes.

Magnetic Core-Shell Silica Nanoparticles with Large Radial Mesopores for siRNA Delivery.

PubMed

Xiong, Lin; Bi, Jingxu; Tang, Youhong; Qiao, Shi-Zhang

2016-09-01

A novel type of magnetic core-shell silica nanoparticles is developed for small interfering RNA (siRNA) delivery. These nanoparticles are fabricated by coating super-paramagnetic magnetite nanocrystal clusters with radial large-pore mesoporous silica. The amine functionalized nanoparticles have small particle sizes around 150 nm, large radial mesopores of 12 nm, large surface area of 411 m(2) g(-1) , high pore volume of 1.13 cm(3) g(-1) and magnetization of 25 emu g(-1) . Thus, these nanoparticles possess both high loading capacity of siRNA (2 wt%) and strong magnetic response under an external magnetic field. An acid-liable coating composed of tannic acid can further protect the siRNA loaded in these nanoparticles. The coating also increases the dispersion stability of the siRNA-loaded carrier and can serve as a pH-responsive releasing switch. Using the magnetic silica nanoparticles with tannic acid coating as carriers, functional siRNA has been successfully delivered into the cytoplasm of human osteosarcoma cancer cells in vitro. The delivery is significantly enhanced with the aid of the external magnetic field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Image-guided interventional therapy for cancer with radiotherapeutic nanoparticles✩

PubMed Central

Phillips, William T.; Bao, Ande; Brenner, Andrew J.; Goins, Beth A.

2015-01-01

One of the major limitations of current cancer therapy is the inability to deliver tumoricidal agents throughout the entire tumor mass using traditional intravenous administration. Nanoparticles carrying beta-emitting therapeutic radionuclides that are delivered using advanced image-guidance have significant potential to improve solid tumor therapy. The use of image-guidance in combination with nanoparticle carriers can improve the delivery of localized radiation to tumors. Nanoparticles labeled with certain beta-emitting radionuclides are intrinsically theranostic agents that can provide information regarding distribution and regional dosimetry within the tumor and the body. Image-guided thermal therapy results in increased uptake of intravenous nanoparticles within tumors, improving therapy. In addition, nanoparticles are ideal carriers for direct intratumoral infusion of beta-emitting radionuclides by convection enhanced delivery, permitting the delivery of localized therapeutic radiation without the requirement of the radionuclide exiting from the nanoparticle. With this approach, very high doses of radiation can be delivered to solid tumors while sparing normal organs. Recent technological developments in image-guidance, convection enhanced delivery and newly developed nanoparticles carrying beta-emitting radionuclides will be reviewed. Examples will be shown describing how this new approach has promise for the treatment of brain, head and neck, and other types of solid tumors. PMID:25016083

Antibody-functionalized polymer nanoparticle leading to memory recovery in Alzheimer's disease-like transgenic mouse model.

PubMed

Carradori, Dario; Balducci, Claudia; Re, Francesca; Brambilla, Davide; Le Droumaguet, Benjamin; Flores, Orfeu; Gaudin, Alice; Mura, Simona; Forloni, Gianluigi; Ordoñez-Gutierrez, Lara; Wandosell, Francisco; Masserini, Massimo; Couvreur, Patrick; Nicolas, Julien; Andrieux, Karine

2018-02-01

Alzheimer's disease (AD) is a neurodegenerative disorder related, in part, to the accumulation of amyloid-β peptide (Aβ) and especially the Aβ peptide 1-42 (Aβ 1-42 ). The aim of this study was to design nanocarriers able to: (i) interact with the Aβ 1-42 in the blood and promote its elimination through the "sink effect" and (ii) correct the memory defect observed in AD-like transgenic mice. To do so, biodegradable, PEGylated nanoparticles were surface-functionalized with an antibody directed against Aβ 1-42 . Treatment of AD-like transgenic mice with anti-Aβ 1-42 -functionalized nanoparticles led to: (i) complete correction of the memory defect; (ii) significant reduction of the Aβ soluble peptide and its oligomer level in the brain and (iii) significant increase of the Aβ levels in plasma. This study represents the first example of Aβ 1-42 monoclonal antibody-decorated nanoparticle-based therapy against AD leading to complete correction of the memory defect in an experimental model of AD. Copyright © 2017 Elsevier Inc. All rights reserved.

Gram scale synthesis of Fe/Fe xO y core–shell nanoparticles and their incorporation into matrix-free superparamagnetic nanocomposites

DOE PAGES

Watt, John Daniel; Bleier, Grant C.; Romero, Zachary William; ...

2018-05-15

In this paper, significant reductions recently seen in the size of wide-bandgap power electronics have not been accompanied by a relative decrease in the size of the corresponding magnetic components. To achieve this, a new generation of materials with high magnetic saturation and permeability are needed. Here, we develop gram-scale syntheses of superparamagnetic Fe/Fe xO y core–shell nanoparticles and incorporate them as the magnetic component in a strongly magnetic nanocomposite. Nanocomposites are typically formed by the organization of nanoparticles within a polymeric matrix. However, this approach can lead to high organic fractions and phase separation; reducing the performance of themore » resulting material. Here, we form aminated nanoparticles that are then cross-linked using epoxy chemistry. The result is a magnetic nanoparticle component that is covalently linked and well separated. By using this ‘matrix-free’ approach, we can substantially increase the magnetic nanoparticle fraction, while still maintaining good separation, leading to a superparamagnetic nanocomposite with strong magnetic properties.« less

Triblock copolymers encapsulated poly (aryl benzyl ether) dendrimer zinc(II) phthalocyanine nanoparticles for enhancement in vitro photodynamic efficacy.

PubMed

Huang, Yide; Yu, Huizhen; Lv, Huafei; Zhang, Hong; Ma, Dongdong; Yang, Hongqin; Xie, Shusen; Peng, Yiru

2016-12-01

A novel series of nanoparticles formed via an electrostatic interaction between the periphery of negatively charged 1-2 generation aryl benzyl ether dendrimer zinc (II) phthalocyanines and positively charged poly(L-lysin) segment of triblock copolymer, poly(L-lysin)-block-poly(ethylene glycol)-block-poly(L-lysin), was developed for the use as an effective photosensitizers in photodynamic therapy. The dynamic light scattering, atomic force microscopy showed that two nanoparticles has a relevant size of 80-150nm. The photophysical properties and singlet oxygen quantum yields of free dendrimer phthalocyanines and nanoparticles exhibited generation dependence. The intracellular uptake of dendrimer phthalocyanines in Hela cells was significantly elevated as they were incorporated into the micelles, but was inversely correlated with the generation of dendrimer phthalocyanines. The photocytotoxicity of dendrimer phthalocyanines incorporated into polymeric micelles was also increased. The presence of nanoparticles induced efficient cell death. Using a mitochondrial-sepcific dye rhodamine 123 (Rh123), our fluorescence microscopic result indicated that nanoparticles localized to the mitochondria. Copyright © 2016 Elsevier B.V. All rights reserved.

Biosynthesis of silver nanoparticles using dried fruit extract of Ficus carica - Screening for its anticancer activity and toxicity in animal models.

PubMed

Jacob, S Justin Packia; Prasad, V L Siva; Sivasankar, S; Muralidharan, P

2017-11-01

There is an increasing commercial demand for various nanoparticles due to their extensive applicability in various areas such as electronics, catalysis, chemistry, energy and medicine. Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are quite often toxic and flammable. Fig has been a typical fruit component of the health-promoting Mediterranean diet for a very long time. In the present study, we describe a cost effective and eco-friendly technique for green synthesis of silver nanoparticles from 1 mM AgNO3 solution through the extract of dried fig (Ficus carica L.) fruit as reducing as well as capping agent. Nanoparticles were characterized using UV absorption spectroscopy and SEM. The sizes of the spherical silver particles were found to be in the range of 54-89 nm. The biologically synthesized nanoparticles also exhibited a significant cytotoxic effect on MCF7cell lines and further animal acute toxicity results state that the above AgNPs are toxicologically safe by oral administration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gram scale synthesis of Fe/Fe xO y core–shell nanoparticles and their incorporation into matrix-free superparamagnetic nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watt, John Daniel; Bleier, Grant C.; Romero, Zachary William

In this paper, significant reductions recently seen in the size of wide-bandgap power electronics have not been accompanied by a relative decrease in the size of the corresponding magnetic components. To achieve this, a new generation of materials with high magnetic saturation and permeability are needed. Here, we develop gram-scale syntheses of superparamagnetic Fe/Fe xO y core–shell nanoparticles and incorporate them as the magnetic component in a strongly magnetic nanocomposite. Nanocomposites are typically formed by the organization of nanoparticles within a polymeric matrix. However, this approach can lead to high organic fractions and phase separation; reducing the performance of themore » resulting material. Here, we form aminated nanoparticles that are then cross-linked using epoxy chemistry. The result is a magnetic nanoparticle component that is covalently linked and well separated. By using this ‘matrix-free’ approach, we can substantially increase the magnetic nanoparticle fraction, while still maintaining good separation, leading to a superparamagnetic nanocomposite with strong magnetic properties.« less

Antimicrobial function of Nd3+-doped anatase titania-coated nickel ferrite composite nanoparticles: a biomaterial system.

PubMed

Rana, S; Rawat, J; Sorensson, M M; Misra, R D K

2006-07-01

The present study describes and makes a relative comparison of the antimicrobial function of undoped and neodymium-doped titania coated-nickel ferrite composite nanoparticles processed by uniquely combining the reverse micelle and chemical hydrolysis approaches. This methodology facilitates the formation of undoped and doped photocatalytic titania shells and a magnetic ferrite core. The ferrite core is needed to help in the removal of particles from the sprayed surface using a small magnetic field. Doping of the titania shell with neodymium significantly enhances the photocatalytic and anti-microbial function of the core-shell composite nanoparticles without influencing the magnetic characteristics of the nickel ferrite core. The increased performance is believed to be related to the inhibition of electron-hole recombination and a decrease in the band gap energy of titania. The retention of magnetic strength ensures controlled movement of the composite nanoparticles by the magnetic field, facilitating their application as removable anti-microbial photocatalyst nanoparticles. The consistent behavior of the composite nanoparticles points to the viability of the synthesis process adopted.

Redox-responsive nanoparticles with Aggregation-Induced Emission (AIE) characteristic for fluorescence imaging.

PubMed

Cheng, Weiren; Wang, Guan; Pan, Xiaoyong; Zhang, Yong; Tang, Ben Zhong; Liu, Ye

2014-08-01

The redox environment between intracellular compartments and extracellular matrix is significantly different, and the cellular redox homeostasis determines many physiological functions. Here, redox-responsive nanoparticles with aggregation-induced emission (AIE) characteristic for fluorescence imaging are developed by encapsulation of fluorophore with redox "turn-on" AIE characteristic, TPE-MI, into the micelles of poly(ethylene glycol) (PEG)- and cholesterol (CE)-conjugated disulfide containing poly(amido amine)s. The redox-responsive fluorescence profiles of the nanoparticles are investigated after reaction with glutathione (GSH). The encapsulation of TPE-MI in micelles leads to a higher efficiency and red shift in emission, and the fluorescence intensity of the nanoparticles increases with the concentration of GSH. Confocal microscopy imaging shows that the nanoparticles can provide obvious contrast between the intracellular compartments and the extracellular matrix in MCF-7 and HepG2 cells. So the nanoparticles with PEG shells and low cytotoxicity are promising to provide fluorescence bioimaging with a high contrast and for differentiation of cellular redox environment. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wrinkling instability in graphene supported on nanoparticle-patterned SiO2

NASA Astrophysics Data System (ADS)

Cullen, William; Yamamoto, Mahito; Pierre-Louis, Olivier; Einstein, Theodore; Fuhrer, Michael

2012-02-01

Atomically-thin graphene is arguably the thinnest possible mechanical membrane: graphene's effective thickness (the thickness of an isotropic continuum slab which would have the same elastic and bending stiffness) is significantly less than 1 å, indicating that graphene can distort out-of-plane to conform to sub-nanometer features. Here we study the elastic response of graphene supported on a SiO2 substrate covered with SiO2 nanoparticles. At a low density of nanoparticles, graphene is largely pinned to the substrate due to adhesive interaction. However, with increasing nanoparticle density, graphene's elasticity dominates adhesion and strain is relieved by the formation of wrinkles which connect peaks introduced by the supporting nanoparticles. At a critical density, the wrinkles percolate, resulting in a wrinkle network. We develop a simple elastic model allowing for adhesion which accurately predicts the critical spacing between nanoparticles for wrinkle formation. This work has been supported by the University of Maryland NSF-MRSEC under Grant No. DMR 05-20471 with supplemental funding from NRI, and NSF-DMR 08-04976.

Tissue deposition and toxicological effects of commercially significant rare earth oxide nanomaterials: Material and physical properties.

PubMed

Das, Soumen; Reed McDonagh, Philip; Selvan Sakthivel, Tamil; Barkam, Swetha; Killion, Kelsey; Ortiz, Julian; Saraf, Shashank; Kumar, Amit; Gupta, Ankur; Zweit, Jamal; Seal, Sudipta

2017-03-01

Rare earth oxide (REO) materials are found naturally in earth's crust and at the nanoscale these REO nanoparticles exhibit unique thermal, electrical, and physicochemical properties. REO nanoparticles are widely used in different industrial sectors for ceramics, glass polishing, metallurgy, lasers, and magnets. Recently, some of these REO nanoparticles have been identified for their potential application in medicine, including therapy, imaging, and diagnostics. Concurrent research into the REO nanomaterials' toxicities has also raised concern for their environmental impacts. The correlation of REO nanoparticles mediated toxicity with their physiochemical properties can help to design nanoparticles with minimal effect on the environment and living organisms. In vitro assay revealed toxicity toward Human squamous epithelial cell line (CCL30) and Human umbilical vascular endothelial cells (HUVEC) at a concentration of 100 µM and higher. In vivo results showed, with the exception of CeO 2 and Gd 2 O 3 , most of the naoparticles did not clear or had minimum clearance (10-20%) from the system. Elevated levels of alanine transferase were seen for animals given each different nanoparticle, however the increases were not significant for CeO 2 and Dy 2 O 3 . Nephrotoxicity was only seen in case of Dy 2 O 3 and Gd 2 O 3 . Lastly, histological examination revealed presence of swollen hepatocytes which further confirms toxicity of the commercial REO nanomaterials. The in vivo toxicity is mainly due to excessive tissue deposition (70-90%) due to the commercial REO nanoparticles' poor physical properties (shape, stability, and extent of agglomeration). Therefore, optimization of nanoparticles physical properties is very important. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 904-917, 2017. © 2016 Wiley Periodicals, Inc.

The effect of different desolvating agents on BSA nanoparticle properties and encapsulation of curcumin

NASA Astrophysics Data System (ADS)

Sadeghi, R.; Moosavi-Movahedi, A. A.; Emam-jomeh, Z.; Kalbasi, A.; Razavi, S. H.; Karimi, M.; Kokini, J.

2014-09-01

The desolvation method was successfully used to prepare nanoparticles from bovine serum albumin (BSA) using ethanol, acetone, and their mixtures (70:30 and 50:50, respectively). Ethanol and mixtures of ethanol and acetone led to the most spherical nanoparticles, while using pure acetone resulted in a mixture of spherical and rod shape nanoparticle. Acetone was the solvent with higher encapsulation efficiency equal to 99.2 ± 0.36 %. The polydispersity values of BSA NPs in this study were 0.045 ± 0.007, 0.065 ± 0.013, 0.091 ± 0.012, and 0.120 ± 0.016 for ethanol (100) 4×, Et:Ac (70:30) 4×, Et:Ac (50:50) 4×, and acetone (100) 3×, respectively. Encapsulation efficiencies of curcumin inside BSA NPs were 19.4 ± 2.2 and 19.8 ± 1.6 % for 1.0 and 1.5 molar ratios of curcumin to BSA, respectively. Crosslinking using glutaraldehyde improved the stability of BSA NPs and curcumin-loaded BSA NPs and both groups of nanoparticles were stable for 1 month; the lyophilized curcumin-loaded BSA NPs were able to redisperse in water. The particle size and polydispersity index of redispersed NPs were higher than the original NPs before lyophilization. The size distribution study shows that after 10 s of sonication most nanoparticles were well dispersed; however, a small but significant fraction formed aggregates. Sonication for 10 s decreased the effective diameter and polydispersity of the redispersed nanoparticles, while increasing the sonication time to 20 s did not show significant changes. In vitro release study of curcumin from BSA NPs showed that these biocompatible nanoparticles have the ability to be used as a carrier to improve controlled release of curcumin.

Paracrine signalling of inflammatory cytokines from an in vitro blood brain barrier model upon exposure to polymeric nanoparticles.

PubMed

Raghnaill, Michelle Nic; Bramini, Mattia; Ye, Dong; Couraud, Pierre-Olivier; Romero, Ignacio A; Weksler, Babette; Åberg, Christoffer; Salvati, Anna; Lynch, Iseult; Dawson, Kenneth A

2014-03-07

Nanoparticle properties, such as small size relative to large highly modifiable surface area, offer great promise for neuro-therapeutics and nanodiagnostics. A fundamental understanding and control of how nanoparticles interact with the blood-brain barrier (BBB) could enable major developments in nanomedical treatment of previously intractable neurological disorders, and help ensure that nanoparticles not intended to reach the brain do not cause adverse effects. Nanosafety is of utmost importance to this field. However, a distinct lack of knowledge exists regarding nanoparticle accumulation within the BBB and the biological effects this may induce on neighbouring cells of the Central Nervous System (CNS), particularly in the long-term. This study focussed on the exposure of an in vitro BBB model to model carboxylated polystyrene nanoparticles (PS COOH NPs), as these nanoparticles are well characterised for in vitro experimentation and have been reported as non-toxic in many biological settings. TEM imaging showed accumulation but not degradation of 100 nm PS COOH NPs within the lysosomes of the in vitro BBB over time. Cytokine secretion analysis from the in vitro BBB post 24 h 100 nm PS COOH NP exposure showed a low level of pro-inflammatory RANTES protein secretion compared to control. In contrast, 24 h exposure of the in vitro BBB endothelium to 100 nm PS COOH NPs in the presence of underlying astrocytes caused a significant increase in pro-survival signalling. In conclusion, the tantalising possibilities of nanomedicine must be balanced by cautious studies into the possible long-term toxicity caused by accumulation of known 'toxic' and 'non-toxic' nanoparticles, as general toxicity assays may be disguising significant signalling regulation during long-term accumulation.

Development and testing of gold nanoparticles for drug delivery and treatment of heart failure: a theranostic potential for PPP cardiology.

PubMed

Spivak, Mykola Ya; Bubnov, Rostyslav V; Yemets, Ilya M; Lazarenko, Liudmyla M; Tymoshok, Natalia O; Ulberg, Zoia R

2013-07-29

Nanoscale gold particles (AuNPs) have wide perspectives for biomedical applications because of their unique biological properties, as antioxidative activity and potentials for drug delivery. The aim was to test effects of AuNPs using suggested heart failure rat model to compare with proved medication Simdax, to test gold nanoparticle for drug delivery, and to test sonoporation effect to increase nanoparticles delivery into myocardial cells. We performed biosafety and biocompatibility tests for AuNPs and conjugate with Simdax. For in vivo tests, we included Wistar rats weighing 180-200 g (n = 54), received doxorubicin in cumulative dose of 12.0 mg/kg to model advance heart failure, registered by ultrasonography. We formed six groups: the first three groups of animals received, respectively, 0.06 ml Simdax, AuNPs, and conjugate (AuNPs-Simdax), intrapleurally, and the second three received them intravenously. The seventh group was control (saline). We performed dynamic assessment of heart failure regression in vivo measuring hydrothorax. Sonoporation of gold nanoparticles to cardiomyocytes was tested. We designed and constructed colloidal, spherical gold nanoparticles, AuNPs-Simdax conjugate, both founded biosafety (in cytotoxicity, genotoxicity, and immunoreactivity). In all animals of the six groups after the third day post-medication injection, no ascites and liver enlargement were registered (P < 0.001 vs controls). Conjugate injection showed significantly higher hydrothorax reduction than Simdax injection only (P < 0.01); gold nanoparticle injection showed significantly higher results than Simdax injection (P < 0.05). AuNPs and conjugate showed no significant difference for rat recovery. Difference in rat life continuity was significant between Simdax vs AuNPs (P < 0.05) and Simdax vs conjugate (P < 0.05). Sonoporation enhances AuNP transfer into the cell and mitochondria that were highly localized, superior to controls (P < 0.01 for both). Gold nanoparticles of 30 nm and its AuNPs-Simdax conjugate gave positive results in biosafety and biocompatibility in vitro and in vivo. AuNPs-Simdax and AuNPs have similar significant cardioprotective effects in rats with doxorubicin-induced heart failure, higher than that of Simdax. Intrapleural (local) delivery is preferred over intravenous (systemic) delivery according to all tested parameters. Sonoporation is able to enhance gold nanoparticle delivery to myocardial cells in vivo.

Cytotoxicity of aluminium oxide nanoparticles towards fresh water algal isolate at low exposure concentrations.

PubMed

Pakrashi, Sunandan; Dalai, Swayamprava; T C, Prathna; Trivedi, Shruti; Myneni, Radhika; Raichur, Ashok M; Chandrasekaran, N; Mukherjee, Amitava

2013-05-15

The growing commercial applications had brought aluminium oxide nanoparticles under toxicologists' purview. In the present study, the cytotoxicity of two different sized aluminium oxide nanoparticles (ANP(1), mean hydrodynamic diameter 82.6±22nm and ANP(2), mean hydrodynamic diameter 246.9±39nm) towards freshwater algal isolate Chlorella ellipsoids at low exposure levels (≤1μg/mL) using sterile lake water as the test medium was assessed. The dissolution of alumina nanoparticles and consequent contribution towards toxicity remained largely unexplored owing to its presumed insoluble nature. Herein, the leached Al(3+) ion mediated toxicity has been studied along with direct particulate toxicity to bring out the dynamics of toxicity through colloidal stability, biochemical, spectroscopic and microscopic analyses. The mean hydrodynamic diameter increased with time both for ANP(1) [82.6±22nm (0h) to 246.3±59nm (24h), to 1204±140nm (72h)] and ANP(2) [246.9±39nm (0h) to 368.28±48nm (24h), to 1225.96±186nm (72h)] signifying decreased relative abundance of submicron sized particles (<1000nm). The detailed cytotoxicity assays showed a significant reduction in the viability dependent on dose and exposure. A significant increase in ROS and LDH levels were noted for both ANPs at 1μg/mL concentration. The zeta potential and FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (SEM, TEM, and CLSM). At 72h, significant Al(3+) ion release in the test medium [0.092μg/mL for ANP(1), and 0.19μg/mL for ANP(2)] was noted, and the resulting suspension containing leached ions caused significant cytotoxicity, revealing a substantial ionic contribution. This study indicates that both the nano-size and ionic dissolution play a significant role in the cytotoxicity of ANPs towards freshwater algae, and the exposure period largely determines the prevalent mode of nano-toxicity. Copyright © 2013 Elsevier B.V. All rights reserved.

Ideal versus real: simulated annealing of experimentally derived and geometric platinum nanoparticles

NASA Astrophysics Data System (ADS)

Ellaby, Tom; Aarons, Jolyon; Varambhia, Aakash; Jones, Lewys; Nellist, Peter; Ozkaya, Dogan; Sarwar, Misbah; Thompsett, David; Skylaris, Chris-Kriton

2018-04-01

Platinum nanoparticles find significant use as catalysts in industrial applications such as fuel cells. Research into their design has focussed heavily on nanoparticle size and shape as they greatly influence activity. Using high throughput, high precision electron microscopy, the structures of commercially available Pt catalysts have been determined, and we have used classical and quantum atomistic simulations to examine and compare them with geometric cuboctahedral and truncated octahedral structures. A simulated annealing procedure was used both to explore the potential energy surface at different temperatures, and also to assess the effect on catalytic activity that annealing would have on nanoparticles with different geometries and sizes. The differences in response to annealing between the real and geometric nanoparticles are discussed in terms of thermal stability, coordination number and the proportion of optimal binding sites on the surface of the nanoparticles. We find that annealing both experimental and geometric nanoparticles results in structures that appear similar in shape and predicted activity, using oxygen adsorption as a measure. Annealing is predicted to increase the catalytic activity in all cases except the truncated octahedra, where it has the opposite effect. As our simulations have been performed with a classical force field, we also assess its suitability to describe the potential energy of such nanoparticles by comparing with large scale density functional theory calculations.

Excipient-assisted vinpocetine nanoparticles: experiments and molecular dynamic simulations.

PubMed

Li, Cai-Xia; Wang, Hao-Bo; Oppong, Daniel; Wang, Jie-Xin; Chen, Jian-Feng; Le, Yuan

2014-11-03

Hydrophilic excipients can be used to increase the solubility and bioavailability of poorly soluble drugs. In this work, the conventional water-soluble pharmaceutical excipients hydroxypropylmethylcellulose (HPMC), polyvinylpyrrolidone (PVP), and lactose (LAC) were used as solid supports to prevent drug nanoparticles from aggregation and enhance drug dissolution. Excipient-assisted vinpocetine (VIN) nanoparticles were prepared by reactive precipitation. The analysis results indicated that HPMC was a suitable excipient to prepare VIN nanoparticles. VIN/HPMC nanoparticles had a mean size of 130 nm within a narrow distribution. The dissolution rate of VIN nanoparticles was significantly faster than those of a physical mixture of VIN/HPMC and raw VIN. VIN/HPMC nanoparticles had a higher dissolution profile than VIN/PVP and VIN/LAC nanoparticles. Besides, molecular dynamics (MD) simulation was applied to investigate the molecular interactions between VIN and excipients. The calculated results revealed that VIN interacted with excipients by Coulomb and Lennard-Jones (LJ) interactions. Few hydrogen bonds were formed between VIN and excipients. The HPMC affording smaller particle size may be a result of the stronger interactions between VIN and HPMC (mainly LJ interaction) and the property of HPMC. These characteristics may greatly influence the adsorption behavior and may be the crucial parameter for the better performance of HPMC.

Interaction of amino acid-functionalized silver nanoparticles and Candida albicans polymorphs: A deep-UV fluorescence imaging study.

PubMed

Dojčilović, Radovan; Pajović, Jelena D; Božanić, Dušan K; Bogdanović, Una; Vodnik, Vesna V; Dimitrijević-Branković, Suzana; Miljković, Miona G; Kaščaková, Slavka; Réfrégiers, Matthieu; Djoković, Vladimir

2017-07-01

The interaction of the tryptophan functionalized Ag nanoparticles and live Candida albicans cells was studied by synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging at the DISCO beamline of Synchrotron SOLEIL. DUV imaging showed that incubation of the fungus with functionalized nanoparticles results in significant increase in the fluorescence signal. The analysis of the images revealed that the interaction of the nanoparticles with (pseudo)hyphae polymorphs of the diploid fungus was less pronounced than in the case of yeast cells or budding spores. The changes in the intensity of the fluorescence signals of the cells after incubation were followed in [327-353nm] and [370-410nm] spectral ranges that correspond to the fluorescence of tryptophan in non-polar and polar environment, respectively. As a consequence of the environmental sensitivity of the silver-tryptophan fluorescent nanoprobe, we were able to determine the possible accumulation sites of the nanoparticles. The analysis of the intensity decay kinetics showed that the photobleaching effects were more pronounced in the case of the functionalized nanoparticle treated cells. The results of time-integrated emission in the mentioned spectral ranges suggested that the nanoparticles penetrate the cells, but that the majority of the nanoparticles attach to the cells' surfaces. Copyright © 2017 Elsevier B.V. All rights reserved.

Biomedical applications of green synthesized Nobel metal nanoparticles.

PubMed

Khan, Zia Ul Haq; Khan, Amjad; Chen, Yongmei; Shah, Noor S; Muhammad, Nawshad; Khan, Arif Ullah; Tahir, Kamran; Khan, Faheem Ullah; Murtaza, Behzad; Hassan, Sadaf Ul; Qaisrani, Saeed Ahmad; Wan, Pingyu

2017-08-01

Synthesis of Nobel metal nanoparticles, play a key role in the field of medicine. Plants contain a substantial number of organic constituents, like phenolic compounds and various types of glycosides that help in synthesis of metal nanoparticles. Synthesis of metal nanoparticles by green method is one of the best and environment friendly methods. The major significance of the green synthesis is lack of toxic by-products produced during metal nanoparticle synthesis. The nanoparticles, synthesized by green method show various significant biological activities. Most of the research articles report the synthesized nanoparticles to be active against gram positive and gram negative bacteria. Some of these bacteria include Escherichia coli, Bacillus subtilis, Klebsiella pneumonia and Pseudomonas fluorescens. The synthesized nanoparticles also show significant antifungal activity against Trichophyton simii, Trichophyton mentagrophytes and Trichophyton rubrum as well as different types of cancer cells such as breast cancer cell line. They also exhibit significant antioxidant activity. The activities of these Nobel metal nano-particles mainly depend on the size and shape. The particles of small size with large surface area show good activity in the field of medicine. The synthesized nanoparticles are also active against leishmanial diseases. This research article explores in detail the green synthesis of the nanoparticles and their uses thereof. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural, optical, and photoluminescence characterization of electron beam evaporated ZnS/CdSe nanoparticles thin films

NASA Astrophysics Data System (ADS)

Mohamed, S. H.; Ali, H. M.

2011-01-01

Structural, optical, and photoluminescence investigations of ZnS capped with CdSe films prepared by electron beam evaporation are presented. X-ray diffraction analysis revealed that the ZnS/CdSe nanoparticles films contain cubic cadmium selenide and hexagonal zinc sulfide crystals and the ZnS grain sizes increased with increasing ZnS thickness. The refractive index was evaluated in terms of envelope method, which has been suggested by Swanepoel in the transparent region. The refractive index values were found to increase with increasing ZnS thickness. However, the optical band gap and the extinction coefficient were decreased with increasing ZnS thickness. Photoluminescence (PL) investigations revealed the presence of two broad emission bands. The ZnS thickness significantly influenced the PL intensities.

Nanoparticles based fiber optic SPR sensor

NASA Astrophysics Data System (ADS)

Shah, Kruti; Sharma, Navneet K.

2018-05-01

Localized surface plasmon resonance based fiber optic sensor using platinum nanoparticles is proposed and theoretically analyzed. Increase in thickness of nanoparticles layer increases the sensitivity of sensor. 50 nm thick platinum nanoparticles layer based sensor reveals highest sensitivity.

Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

NASA Astrophysics Data System (ADS)

Li, Hongyan; Klem, Michael T.; Sebby, Karl B.; Singel, David J.; Young, Mark; Douglas, Trevor; Idzerda, Yves U.

2009-02-01

Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size.

Thermoelectric properties of SrTiO3 nano-particles dispersed indium selenide bulk composites

NASA Astrophysics Data System (ADS)

Lee, Min Ho; Rhyee, Jong-Soo; Vaseem, Mohammad; Hahn, Yoon-Bong; Park, Su-Dong; Jin Kim, Hee; Kim, Sung-Jin; Lee, Hyeung Jin; Kim, Chilsung

2013-06-01

We investigated the thermoelectric properties of the InSe, InSe/In4Se3 composite, and SrTiO3 (STO) nano-particles dispersed InSe/In4Se3 bulk composites. The electrical conductivity of the InSe/In4Se3 composite with self-assembled phase separation is significantly increased compared with those of InSe and In4Se3-δ implying the enhancement of surface conductivity between grain boundaries. The thermal conductivity of InSe/In4Se3 composite is decreased compared to those of InSe. When the STO nano-particle dispersion was employed in the InSe/In4Se3 composite, a coherent interface was observed between nano-particle precipitates and the InSe bulk matrix with a reduction of the thermal conductivity.

Effects of aluminum oxide nanoparticles on the growth, development, and microRNA expression of tobacco (Nicotiana tabacum).

PubMed

Burklew, Caitlin E; Ashlock, Jordan; Winfrey, William B; Zhang, Baohong

2012-01-01

Nanoparticles are a class of newly emerging environmental pollutions. To date, few experiments have been conducted to investigate the effect nanoparticles may have on plant growth and development. It is important to study the effects nanoparticles have on plants because they are stationary organisms that cannot move away from environmental stresses like animals can, therefore they must overcome these stresses by molecular routes such as altering gene expression. microRNAs (miRNA) are a newly discovered, endogenous class of post-transcriptional gene regulators that function to alter gene expression by either targeting mRNAs for degradation or inhibiting mRNAs translating into proteins. miRNAs have been shown to mediate abiotic stress responses such as drought and salinity in plants by altering gene expression, however no study has been performed on the effect of nanoparticles on the miRNA expression profile; therefore our aim in this study was to classify if certain miRNAs play a role in plant response to Al(2)O(3) nanoparticle stress. In this study, we exposed tobacco (Nicotiana tabacum) plants (an important cash crop as well as a model organism) to 0%, 0.1%, 0.5%, and 1% Al(2)O(3) nanoparticles and found that as exposure to the nanoparticles increased, the average root length, the average biomass, and the leaf count of the seedlings significantly decreased. We also found that miR395, miR397, miR398, and miR399 showed an extreme increase in expression during exposure to 1% Al(2)O(3) nanoparticles as compared to the other treatments and the control, therefore these miRNAs may play a key role in mediating plant stress responses to nanoparticle stress in the environment. The results of this study show that Al(2)O(3) nanoparticles have a negative effect on the growth and development of tobacco seedlings and that miRNAs may play a role in the ability of plants to withstand stress to Al(2)O(3) nanoparticles in the environment.

Effects of Aluminum Oxide Nanoparticles on the Growth, Development, and microRNA Expression of Tobacco (Nicotiana tabacum)

PubMed Central

Burklew, Caitlin E.; Ashlock, Jordan; Winfrey, William B.; Zhang, Baohong

2012-01-01

Nanoparticles are a class of newly emerging environmental pollutions. To date, few experiments have been conducted to investigate the effect nanoparticles may have on plant growth and development. It is important to study the effects nanoparticles have on plants because they are stationary organisms that cannot move away from environmental stresses like animals can, therefore they must overcome these stresses by molecular routes such as altering gene expression. microRNAs (miRNA) are a newly discovered, endogenous class of post-transcriptional gene regulators that function to alter gene expression by either targeting mRNAs for degradation or inhibiting mRNAs translating into proteins. miRNAs have been shown to mediate abiotic stress responses such as drought and salinity in plants by altering gene expression, however no study has been performed on the effect of nanoparticles on the miRNA expression profile; therefore our aim in this study was to classify if certain miRNAs play a role in plant response to Al2O3 nanoparticle stress. In this study, we exposed tobacco (Nicotiana tabacum) plants (an important cash crop as well as a model organism) to 0%, 0.1%, 0.5%, and 1% Al2O3 nanoparticles and found that as exposure to the nanoparticles increased, the average root length, the average biomass, and the leaf count of the seedlings significantly decreased. We also found that miR395, miR397, miR398, and miR399 showed an extreme increase in expression during exposure to 1% Al2O3 nanoparticles as compared to the other treatments and the control, therefore these miRNAs may play a key role in mediating plant stress responses to nanoparticle stress in the environment. The results of this study show that Al2O3 nanoparticles have a negative effect on the growth and development of tobacco seedlings and that miRNAs may play a role in the ability of plants to withstand stress to Al2O3 nanoparticles in the environment. PMID:22606225

Improvement in bone properties by using risedronate adsorbed hydroxyapatite novel nanoparticle based formulation in a rat model of osteoporosis.

PubMed

Sahana, H; Khajuria, Deepak Kumar; Razdan, Rema; Mahapatra, D Roy; Bhat, M R; Suresh, Sarasija; Rao, R Ramachandra; Mariappan, L

2013-02-01

A superior drug formulation capable of achieving efficient osteogenesis is in imperative demand for the treatment of osteoporosis. In the present study we investigated the potential of using novel risedronate-hydroxyapatite (HA) nanoparticle based formulation in an animal model of established osteoporosis. Nanoparticles of HA loaded with risedronate (NHLR) of various sizes (80-130 nm) were generated for bone targeted drug delivery. Three months after ovariectomy, 36 ovariectomized (OVX) rats were divided into 6 equal groups and treated with various doses of NHLR (500, 350 and 250 microg/kg intravenous single dose) and sodium risedronate (500 microg/kg, intravenous single dose). Untreated OVX and sham OVX served as controls. One month after drug administration, the left tibia and femur were tested for bone mechanical properties and histology, respectively. In the right femur, bone density was measured by method based on Archimedes principle and bone porosity analyses were performed using X-ray imaging. NHLR (250 microg/kg) showed a significant increase in bone density and reduced bone porosity when compared with OVX control. Moreover, NHLR (250 microg/kg) significantly increased bone mechanical properties and bone quality when compared with OVX control. The results strongly suggest that the NHLR, which is a novel nanoparticle based formulation, has a therapeutic advantage over risedronate sodium monotherapy for the treatment of osteoporosis in a rat model of postmenopausal osteoporosis.

Zirconium(IV) oxide: New coating material for nanoresonators for shell-isolated nanoparticle-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Krajczewski, Jan; Abdulrahman, Heman Burhanalden; Kołątaj, Karol; Kudelski, Andrzej

2018-03-01

One tool that can be used for determining the structure and composition of surfaces of various materials (even in in situ conditions) is shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). In SHINERS measurements, the surface under investigation is covered with a layer of surface-protected plasmonic nanoparticles, and then the Raman spectrum of the surface analysed is recorded. The plasmonic cores of the used core-shell structures act as electromagnetic nanoresonators, significantly locally enhancing the intensity of the electric field of the incident radiation, leading to a large increase in the efficiency of the generation of the Raman signal from molecules in the close proximity to the deposited SHINERS nanoresonators. A protective layer (from transparent dielectrics such as SiO2, Al2O3 or TiO2) prevents direct interaction between the plasmonic metal and the analysed surface (such interactions may lead to changes in the structure of the surface) and, in the case of plasmonic cores other than gold cores, the dielectric layer increases the chemical stability of the metal core. In this contribution, we show for the first time that core-shell nanoparticles having a silver core (both a solid and hollow one) and a shell of zirconium(IV) oxide are very efficient SHINERS nanoresonators that are significantly more stable in acidic and alkaline media than the silver-silica core-shell structures typically used for SHINERS experiments.

Genotoxicity of Silver Nanoparticles in Vicia faba: A Pilot Study on the Environmental Monitoring of Nanoparticles

PubMed Central

Patlolla, Anita K.; Berry, Ashley; May, LaBethani; Tchounwou, Paul B.

2012-01-01

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there have been some attempts to determine the toxic effects of AgNPs in mammalian and human cell-lines, there is little information on plants which play a vital role in ecosystems. The study reports the use of Vicia faba root-tip meristem to investigate the genotoxicity of AgNPs under modified GENE-TOX test conditions. The root tip cells of V. faba were treated with four different concentrations of engineered AgNPs dispersion to study toxicological endpoints such as mitotic index (MI), chromosomal aberrations (CA) and micronucleus induction (MN). For each concentration, five sets of microscopy observations were carried out. The results demonstrated that AgNPs exposure significantly increased (p < 0.05) the number of chromosomal aberrations, micronuclei, and decreased the MI in exposed groups compared to control. From this study we infer that AgNPs might have penetrated the plant system and may have impaired mitosis causing CA and MN. The results of this study demonstrate that AgNPs are genotoxic to plant cells. Since plant assays have been integrated as a genotoxicity component in risk assessment for detection of environmental mutagens, they should be given full consideration when evaluating the overall toxicological impact of the nanoparticles in the environment. PMID:22754463

Genotoxicity of silver nanoparticles in Vicia faba: a pilot study on the environmental monitoring of nanoparticles.

PubMed

Patlolla, Anita K; Berry, Ashley; May, LaBethani; Tchounwou, Paul B

2012-05-01

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there have been some attempts to determine the toxic effects of AgNPs in mammalian and human cell-lines, there is little information on plants which play a vital role in ecosystems. The study reports the use of Vicia faba root-tip meristem to investigate the genotoxicity of AgNPs under modified GENE-TOX test conditions. The root tip cells of V. faba were treated with four different concentrations of engineered AgNPs dispersion to study toxicological endpoints such as mitotic index (MI), chromosomal aberrations (CA) and micronucleus induction (MN). For each concentration, five sets of microscopy observations were carried out. The results demonstrated that AgNPs exposure significantly increased (p < 0.05) the number of chromosomal aberrations, micronuclei, and decreased the MI in exposed groups compared to control. From this study we infer that AgNPs might have penetrated the plant system and may have impaired mitosis causing CA and MN. The results of this study demonstrate that AgNPs are genotoxic to plant cells. Since plant assays have been integrated as a genotoxicity component in risk assessment for detection of environmental mutagens, they should be given full consideration when evaluating the overall toxicological impact of the nanoparticles in the environment.

Influence of Fe3O4 Nanoparticles in Hydroxyapatite Scaffolds on Proliferation of Primary Human Fibroblast Cells

NASA Astrophysics Data System (ADS)

Maleki-Ghaleh, H.; Aghaie, E.; Nadernezhad, A.; Zargarzadeh, M.; Khakzad, A.; Shakeri, M. S.; Beygi Khosrowshahi, Y.; Siadati, M. H.

2016-06-01

Modern techniques for expanding stem cells play a substantial role in tissue engineering: the raw material that facilitates regeneration of damaged tissues and treats diseases. The environmental conditions and bioprocessing methods are the primary determinants of the rate of cultured stem cell proliferation. Bioceramic scaffolds made of calcium phosphate are effective substrates for optimal cell proliferation. The present study investigates the effects of two bioceramic scaffolds on proliferating cells in culture media. One scaffold was made of hydroxyapatite and the other was a mixture of hydroxyapatite and ferromagnetic material (Fe3O4 nanoparticles). Disk-shaped (10 mm × 2 mm) samples of the two scaffolds were prepared. Primary human fibroblast proliferation was 1.8- and 2.5-fold faster, respectively, when cultured in the presence of hydroxyapatite or ferrous nanoparticle/hydroxyapatite mixtures. Optical microscopy images revealed that the increased proliferation was due to enhanced cell-cell contact. The presence of magnetic Fe3O4 nanoparticles in the ceramic scaffolds significantly increased cell proliferation compared to hydroxyapatite scaffolds and tissue culture polystyrene.

Towards understanding the mechanisms and the kinetics of nanoparticle penetration through protective gloves

NASA Astrophysics Data System (ADS)

Vinches, L.; Peyrot, C.; Lemarchand, L.; Boutrigue, N.; Zemzem, M.; Wilkinson, K. J.; Hallé, S.; Tufenkji, N.

2015-05-01

Parallel to the increased use of engineered nanoparticles (ENP) in the formulation of commercial products or in medicine, numerous health & safety agencies have recommended the application of the precautionary principle to handle ENP; namely, the recommendation to use protective gloves against chemicals. However, recent studies reveal the penetration of titanium dioxide nanoparticles through nitrile rubber protective gloves in conditions simulating occupational use. This project is designed to understand the links between the penetration of gold nanoparticles (nAu) through nitrile rubber protective gloves and the mechanical and physical behaviour of the elastomer material subjected to conditions simulating occupational use (i.e., mechanical deformations (MD) and sweat). Preliminary analyses show that nAu suspensions penetrate selected glove materials after exposure to prolonged (3 hours) dynamic deformations. Significant morphological changes are observed on the outer surface of the glove sample; namely, the number and the surface of the micropores on the surface increase. Moreover, nitrile rubber protective gloves are also shown to be sensitive to the action of nAu suspension and to the action of the saline solution used to simulate sweat (swelling).

Optical properties of BaTiO3 nanoparticles and silver nanoprisms in polymer host matrices

NASA Astrophysics Data System (ADS)

Requena, Sebastian

Nanocomposites are materials comprised of a host matrix, such as glass or polymer, with embedded nanoparticles. Embedding nanoparticles into the host makes it possible to create materials with properties that are distinctly unique from those of their host and nanoparticle constituents. Nanocomposites can have superior mechanical, thermal, and optical properties compared to their host materials. We characterized the photoluminescent properties of BaTiO3 polymer nanocomposites and the effects of chemically modifying the nanoparticles surface on said properties. BaTiO3 nanopowders of average grain sizes 50 nm and 100 nm were functionalized by (3-aminopropyl)triethoxysilane (3APTS) and mixed with poly(methyl methacrylate)/toluene solution. The nanocomposites films morphology and chemical structure were studied via AFM and FTIR. The photoluminescence spectrum of the pure nanoparticles was composed of an emission at ˜3.0 eV and multiple bands centered at ˜2.5 eV. Surface functionalization of the BaTiO3 nanoparticles via 3APTS increased overall luminescence at room temperature while only enhancing the ˜3.0 eV emission at low-temperature. On the other hand, polymer coating of the functionalized nanoparticles significantly enhances ˜3.0 eV emissions while decreasing emissions associated with near-surface lattice distortions at ˜2.5 eV. Chemical modification of the surface with 3APTS and PMMA presents a pathway to tune and control the photoluminescent properties of BTO nanoparticles. We also present optical studies of two different size distributions of silver triangular nanoprisms, one with a dipole resonance at ˜520 nm and the other with a dipole resonance at ˜650 nm, placed in different media. The silver nanoprisms were embedded in a polyvinyl alcohol (PVA) polymer matrix and oriented by stretching the polymer/nanoprism nanocomposite films. We observe significantly increased linear dichroism in the region associated with the plasmonic in-plane dipole mode upon stretching. Additionally, there is a weaker linear dichroism in the region associated with out-of-plane modes, which vanish in the extinction spectrum of the stretched nanocomposite film. Our results show that these silver nanoprisms are promising as key components in wavelength-specific depolarizers and depolarization-based assays.

Increased cellular uptake of lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles due to surface modification with folic acid.

PubMed

Feuser, Paulo Emilio; Arévalo, Juan Marcelo Carpio; Junior, Enio Lima; Rossi, Gustavo Rodrigues; da Silva Trindade, Edvaldo; Rocha, Maria Eliane Merlin; Jacques, Amanda Virtuoso; Ricci-Júnior, Eduardo; Santos-Silva, Maria Claudia; Sayer, Claudia; de Araújo, Pedro H Hermes

2016-12-01

Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles surface modified with folic acid were synthesized by miniemulsion polymerization in just one step. In vitro biocompatibility and cytotoxicity assays on L929 (murine fibroblast), human red blood, and HeLa (uterine colon cancer) cells were performed. The effect of folic acid at the nanoparticles surface was evaluated through cellular uptake assays in HeLa cells. Results showed that the presence of folic acid did not affect substantially the polymer particle size (~120 nm), the superparamagnetic behavior, the encapsulation efficiency of lauryl gallate (~87 %), the Zeta potential (~38 mV) of the polymeric nanoparticles or the release profile of lauryl gallate. The release profile of lauryl gallate from superparamagnetic poly(methyl methacrylate) nanoparticles presented an initial burst effect (0-1 h) followed by a slow and sustained release, indicating a biphasic release system. Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles with folic acid did not present cytotoxicity effects on L929 and human red blood cells. However, free lauryl gallate presented significant cytotoxic effects on L929 and human red blood cells at all tested concentrations. The presence of folic acid increased the cytotoxicity of lauryl gallate loaded in nanoparticles on HeLa cells due to a higher cellular uptake when HeLa cells were incubated at 37 °C. On the other hand, when the nanoparticles were incubated at low temperature (4 °C) cellular uptake was not observed, suggesting that the uptake occurred by folate receptor mediated energy-dependent endocytosis. Based on presented results our work suggests that this carrier system can be an excellent alternative in targeted drug delivery by folate receptor.

Transport properties of alumina nanofluids.

PubMed

Wong, Kau-Fui Vincent; Kurma, Tarun

2008-08-27

Recent studies have showed that nanofluids have significantly greater thermal conductivity compared to their base fluids. Large surface area to volume ratio and certain effects of Brownian motion of nanoparticles are believed to be the main factors for the significant increase in the thermal conductivity of nanofluids. In this paper all three transport properties, namely thermal conductivity, electrical conductivity and viscosity, were studied for alumina nanofluid (aluminum oxide nanoparticles in water). Experiments were performed both as a function of volumetric concentration (3-8%) and temperature (2-50 °C). Alumina nanoparticles with a mean diameter of 36 nm were dispersed in water. The effect of particle size was not studied. The transient hot wire method as described by Nagaska and Nagashima for electrically conducting fluids was used to test the thermal conductivity. In this work, an insulated platinum wire of 0.003 inch diameter was used. Initial calibration was performed using de-ionized water and the resulting data was within 2.5% of standard thermal conductivity values for water. The thermal conductivity of alumina nanofluid increased with both increase in temperature and concentration. A maximum thermal conductivity of 0.7351 W m(-1) K(-1) was recorded for an 8.47% volume concentration of alumina nanoparticles at 46.6 °C. The effective thermal conductivity at this concentration and temperature was observed to be 1.1501, which translates to an increase in thermal conductivity by 22% when compared to water at room temperature. Alumina being a good conductor of electricity, alumina nanofluid displays an increasing trend in electrical conductivity as volumetric concentration increases. A microprocessor-based conductivity/TDS meter was used to perform the electrical conductivity experiments. After carefully calibrating the conductivity meter's glass probe with platinum tip, using a standard potassium chloride solution, readings were taken at various volumetric concentrations. A 3457.1% increase in the electrical conductivity was measured for a small 1.44% volumetric concentration of alumina nanoparticles in water. The highest value of electrical conductivity, 314 µS cm(-1), was recorded for a volumetric concentration of 8.47%. In the determination of the kinematic viscosity of alumina nanofluid, a standard kinematic viscometer with constant temperature bath was used. Calibrated capillary viscometers were used to measure flow under gravity at precisely controlled temperatures. The capillary viscometers were calibrated with de-ionized water at different temperatures, and the resulting kinematic viscosity values were found to be within 3% of the standard published values. An increase of 35.5% in the kinematic viscosity was observed for an 8.47% volumetric concentration of alumina nanoparticles in water. The maximum kinematic viscosity of alumina nanofluid, 2.901 42 mm(2) s(-1), was obtained at 0 °C for an 8.47% volumetric concentration of alumina nanoparticles. The experimental results of the present work will help researchers arrive at better theoretical models.

Properties of microcement mortar with nano particles

NASA Astrophysics Data System (ADS)

Alimeneti, Narasimha Reddy

Carbon nanotubes (CNT) and Carbon nanofibers (CNF) are one of the toughest and stiffest materials in the world presently with extreme properties yet to be discovered in terms of elastic modulus and tensile strength. Due to the advanced properties of these materials they are being used in almost all fields of science at nanolevel and are being used in construction industry recently for improvement of material properties. Microcement is fine ground cement which as half the particle size of ordinary Portland cement. In this research the behavior of cement mortar of micro cement with the addition of nanoparticles is studied. Due to high aspect ratio and strong van der Waal forces between the particles of CNT and CNF, they agglomerate and form bundles when mixed with water, sonication method is used to mix nanoparticles with few drops of surfactant and super plasticizer. Mechanical properties such as compressive strength and flexural strength with CNT and CNF composites are examined and compared with control samples. 0.1% and 0.05 % of nanoparticles (both CNT and CNF) by the weight of cement are used in this research and 0.8% of super plasticizer by weight of cement was also used along with 0.4, 0.45 and 0.50 water cement ratios for making specimens for compression test. The compressive strength results are not satisfactory as there was no constant increase in strength with all the composites, however strength of few nanocomposites increased by a good percentage. 0.5 water cement ratio cement mortar had compressive strength of 7.15 ksi (49.3 MPa), whereas sample with 0.1% CNT showed 8.38 ksi (57.8 MPa) with 17% increase in strength after 28 days. Same trend was followed by 0.4 water cement ratio as the compressive strength of control sample was 8.89 ksi (61.3 MPa), with 0.05% of CNT strength increased to 10.90 ksi (75.2 MPa) with 23% increase in strength. 0.4 water cement ratio was used for flexural tests including 0.1%, 0.05% of CNT and 0.1%, 0.05% of CNF with 0.008 ratio of super plasticizer. Results showed that there was a significant increase in strength initially but gradually decreased as the time increase and showed decreased strength at 28 days when compared to control samples. Flow cone results are quite satisfying as the flow is significantly increased with the addition of nanoparticles. Time of efflux of control sample is 16.22 sec whereas for specimen with CNT had a time of efflux 12.67 sec and sample with CNF showed 13.65 seconds. Setting time test was carried on 0.4 water cement ratio. Composites with nanoparticles exhibited faster setting when compared to its control sample. Bleeding was not observed with the nanoparticles in the cement mortar. Shrinkage test was conducted on sample with 0.4 water cement ratio with 0.05% of CNT and CNF. Shrinkage was very small in the samples with nanoparticles.

Impact of solvent mixture on iron nanoparticles generated by laser ablation

NASA Astrophysics Data System (ADS)

Chakif, M.; Prymak, O.; Slota, M.; Heintze, E.; Gurevich, E. L.; Esen, C.; Bogani, L.; Epple, M.; Ostendorf, A.

2014-03-01

The present work reveals the structural and magnetic properties of iron oxide (FexOy) nanoparticles (NPs) prepared by femtosecond laser ablation. The FexOy-NPs were produced in solutions consisting of different ratios of water and acetone. Laser ablation in water yields agglomerates and that in acetone yields chain structures whereas that in water/acetone show a mixture of both. We observe significant fabrication dependent properties such as different crystallinities and magnetic behaviors. The structural characterization shows a change from iron (Fe) to a FexOy state of the NPs which depends on the solution composition. Furthermore, transmission electron microscopy measurements exhibit a broad particle size distribution in all samples but with significant differences in the mean sizes. Using magnetic measurements we show that nanoparticles fabricated in pure acetone have lower coercive fields which come along with a smaller mean particle size and therefore increasing superparamagnetic behavior.

Chitosan-based biocatalytic nanoparticles for pollutant removal from wastewater.

PubMed

Alarcón-Payán, Dulce A; Koyani, Rina D; Vazquez-Duhalt, Rafael

2017-05-01

Chitosan, a renewable biopolymer has the prospective applications in different fields due to its gelation capacity. Nanoconfiguration of chitosan through ionotropic gelation to encapsulate enzymatic activity offers numerous potential applications. In the present study, the preparation and characterization of chitosan nanoparticles loaded with versatile peroxidase are reported. Their performance in bioremediation process and the resistance enhancement against natural microbial biodegradation were studied. The average diameter of enzymatic nanoparticles was 120nm and showed a high enzyme loading capacity. The kinetic parameters of nanoparticles exhibited a slightly lower catalytic activity (k cat ), similar affinity constant (Km) for hydrogen peroxide and higher Km value for the phenolic compound when compared with the free enzyme. The enzymatic nanoparticles showed higher thermostability and the same pH activity profile than those from free enzyme. Ten phenolic compounds, including pesticides, halogenated compounds, endocrine disruptors and antibacterials were transformed by the enzymatic nanoparticles. The transformation rate was lower than those obtained with free enzyme suggesting mass transfer limitations. But very importantly, the enzymatic nanoparticles showed a significant increase of the operational stability in real conditions of wastewater treatment process. Moreover, chemical modification of nanoparticles with different aldehydes still enhanced the operational stability of nanoparticulated enzymes. This enhancement of stability in real conditions and the potential use of biocatalytic nanoparticles in bioremediation processes are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

Modeling the atomistic growth behavior of gold nanoparticles in solution

NASA Astrophysics Data System (ADS)

Turner, C. Heath; Lei, Yu; Bao, Yuping

2016-04-01

The properties of gold nanoparticles strongly depend on their three-dimensional atomic structure, leading to an increased emphasis on controlling and predicting nanoparticle structural evolution during the synthesis process. In order to provide this atomistic-level insight and establish a link to the experimentally-observed growth behavior, a kinetic Monte Carlo simulation (KMC) approach is developed for capturing Au nanoparticle growth characteristics. The advantage of this approach is that, compared to traditional molecular dynamics simulations, the atomistic nanoparticle structural evolution can be tracked on time scales that approach the actual experiments. This has enabled several different comparisons against experimental benchmarks, and it has helped transition the KMC simulations from a hypothetical toy model into a more experimentally-relevant test-bed. The model is initially parameterized by performing a series of automated comparisons of Au nanoparticle growth curves versus the experimental observations, and then the refined model allows for detailed structural analysis of the nanoparticle growth behavior. Although the Au nanoparticles are roughly spherical, the maximum/minimum dimensions deviate from the average by approximately 12.5%, which is consistent with the corresponding experiments. Also, a surface texture analysis highlights the changes in the surface structure as a function of time. While the nanoparticles show similar surface structures throughout the growth process, there can be some significant differences during the initial growth at different synthesis conditions.

Effect of Nanoparticles on the Survival and Development of Vitrified Porcine GV Oocytes.

PubMed

Li, W J; Zhou, X L; Liu, B L; Dai, J J; Song, P; Teng, Y

BACKGROUND: Some mammalian oocytes have been successfully cryopreserved by vitrification. However, the survival and developmental rate of vitrified oocytes is still low. The incorporation of nanoparticles into cryoprotectant (CPA) may improve the efficiency of vitrification by changing the properties of solutions. The toxicity of different concentrations of hydroxy apatite (HA), silica dioxide (SO 2 ), aluminum oxide (Al 2 O 3 ) and titanium dioxide (TiO 2 ) nanoparticles (20 nm in diameter) to oocytes was tested and the toxicity threshold value of each nanoparticle was determined. Porcine GV oocytes were vitrified in optimized nano-CPA, and effects of diameter and concentration of nanoparticles on the survival rate and developmental rate of porcine GV oocytes were compared. HA nanoparticles have demonstrated the least toxicity among four nanoparticles and the developmental rate of GV-stage porcine oocytes was 100% when its concentration was lower than 0.5%. By adding 0.1% HA into VS, the developmental rate of GV-stage porcine oocytes (22%) was significantly higher than other groups. The effect of vitrification in nano-CPA on oocytes was related to the concentration of HA nanoparticles rather than their size. By adding 0.05% HA nanoparticles (60nm in diameter), the developmental rate increased dramatically from 14.7% to 30.4%. Nano-cryopreservation offers a new way to improve the effect of survival and development of oocytes, but the limitation of this technology shall not be ignored.

A dose-controlled system for air-liquid interface cell exposure and application to zinc oxide nanoparticles

PubMed Central

2009-01-01

Background Engineered nanoparticles are becoming increasingly ubiquitous and their toxicological effects on human health, as well as on the ecosystem, have become a concern. Since initial contact with nanoparticles occurs at the epithelium in the lungs (or skin, or eyes), in vitro cell studies with nanoparticles require dose-controlled systems for delivery of nanoparticles to epithelial cells cultured at the air-liquid interface. Results A novel air-liquid interface cell exposure system (ALICE) for nanoparticles in liquids is presented and validated. The ALICE generates a dense cloud of droplets with a vibrating membrane nebulizer and utilizes combined cloud settling and single particle sedimentation for fast (~10 min; entire exposure), repeatable (<12%), low-stress and efficient delivery of nanoparticles, or dissolved substances, to cells cultured at the air-liquid interface. Validation with various types of nanoparticles (Au, ZnO and carbon black nanoparticles) and solutes (such as NaCl) showed that the ALICE provided spatially uniform deposition (<1.6% variability) and had no adverse effect on the viability of a widely used alveolar human epithelial-like cell line (A549). The cell deposited dose can be controlled with a quartz crystal microbalance (QCM) over a dynamic range of at least 0.02-200 μg/cm2. The cell-specific deposition efficiency is currently limited to 0.072 (7.2% for two commercially available 6-er transwell plates), but a deposition efficiency of up to 0.57 (57%) is possible for better cell coverage of the exposure chamber. Dose-response measurements with ZnO nanoparticles (0.3-8.5 μg/cm2) showed significant differences in mRNA expression of pro-inflammatory (IL-8) and oxidative stress (HO-1) markers when comparing submerged and air-liquid interface exposures. Both exposure methods showed no cellular response below 1 μg/cm2 ZnO, which indicates that ZnO nanoparticles are not toxic at occupationally allowed exposure levels. Conclusion The ALICE is a useful tool for dose-controlled nanoparticle (or solute) exposure of cells at the air-liquid interface. Significant differences between cellular response after ZnO nanoparticle exposure under submerged and air-liquid interface conditions suggest that pharmaceutical and toxicological studies with inhaled (nano-)particles should be performed under the more realistic air-liquid interface, rather than submerged cell conditions. PMID:20015351

Comparative evaluation of PLGA nanoparticle delivery system for 5-fluorouracil and curcumin on squamous cell carcinoma.

PubMed

Masloub, Shaimaa M; Elmalahy, Mohamed H; Sabry, Dina; Mohamed, Wael S; Ahmed, Sahar H

2016-04-01

The purpose of this study is to assess the effect of 5-fluorouracil nanoparticles and curcumin naoparticles on cell proliferation and the expression of the apoptotic marker (caspase 3) in squamous cell carcinoma cell line. PLGA 5-fluorouracil nanopartciles and PLGA curcumin nanoparticles were prepared and applied for 24 and 48h on human laryngeal squamous carcinoma cell line (Hep-2) as regard IC 50 concentration. MTT assay was used for evaluation of cytotoxicity of prepared nanoparticles. Quantitaive reverse transcriptase polymerase chain reaction (QRT-PCR) was used for the assessment of caspase-3 expression in the treated cell line. The drug release rate profiles was dependent upon polymer to drug ratio, noting that the higher PLGA polymer ratio to 5-fluprouracil or curcumin drug showed faster release rates. On the other hand, the least PLGA polymer ratio to 5-fluprouracil or curcumin drug showed the slowest release rates. MTT assay revelaed that 5-fluorouracil nanoparticels or curcumin nanoparticels showed a clear cytotoxic effect on Hep-2 cell line compared to non treated cancer cells. The RT-PCR assessment of caspase-3 expression revealed that there was a significant increase in caspase-3 expression in Hep-2 cell line treated with 5-fluorouracil nanoparticles or curcumin compared to non treated cancer cells. Curcumin nanoparticles could be more active in inducing apoptosis in short term assays (24h) than long term assays (48h) due to differential cellular uptake. While 5-fluorouracil nanoparticles induced higher significant apoptosis in long term (48h) compared to curcumin group. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removing Bacillus subtilis from fermentation broth using alumina nanoparticles.

PubMed

Mu, Dashuai; Mu, Xin; Xu, Zhenxing; Du, Zongjun; Chen, Guanjun

2015-12-01

In this study, an efficient separation technology using Al2O3 nanoparticles (NPs) was developed for removing Bacillus subtilis from fermentation broth. The dosage of alumina nanoparticles used for separating B. subtilis increased during the culture process and remained stable in the stationary phase of the culture process. The pH of the culture-broth was also investigated for its effects on flocculation efficiency, and showed an acidic pH could enhance the flocculation efficiency. The attachment mechanisms of Al2O3 NPs to the B. subtilis surface were investigated, and the zeta potential analysis showed that Al2O3 NPs could attach to B. subtilis via electrostatic attachment. Finally, the metabolite content and the antibacterial effect of the fermentation supernatants were detected and did not significantly differ between alumina nanoparticle separation and centrifugation separation. Together, these results indicate a great potential for a highly efficient and economical method for removing B. subtilis from fermentation broth using alumina nanoparticles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nanoparticle-mediated knockdown of DNA repair sensitizes cells to radiotherapy and extends survival in a genetic mouse model of glioblastoma.

PubMed

Kievit, Forrest M; Wang, Kui; Ozawa, Tatsuya; Tarudji, Aria W; Silber, John R; Holland, Eric C; Ellenbogen, Richard G; Zhang, Miqin

2017-10-01

Glioblastoma (GBM) remains incurable, and recurrent tumors rarely respond to standard-of-care radiation and chemo-therapies. Therefore, strategies that enhance the effects of these therapies should provide significant benefits to GBM patients. We have developed a nanoparticle delivery vehicle that can stably bind and protect nucleic acids for specific delivery into brain tumor cells. These nanoparticles can deliver therapeutic siRNAs to sensitize GBM cells to radiotherapy and improve GBM treatment via systemic administration. We show that nanoparticle-mediated knockdown of the DNA repair protein apurinic endonuclease 1 (Ape1) sensitizes GBM cells to radiotherapy and extend survival in a genetic mouse model of GBM. Specific knockdown of Ape1 activity by 30% in brain tumor tissue doubled the extended survival achieved with radiotherapy alone. Ape1 is a promising target for increasing the effectiveness of radiotherapy, and nanoparticle-mediated delivery of siRNA is a promising strategy for tumor specific knockdown of Ape1. Copyright © 2017. Published by Elsevier Inc.

Temperature effects on nanostructure and mechanical properties of single-nanoparticle thick membranes.

DOE PAGES

Salerno, Kenneth Michael; Grest, Gary S.

2015-04-30

In this study, the properties of mechanically stable single-nanoparticle (NP)-thick membranes have largely been studied at room temperature. How these membranes soften as nanoparticle ligands disorder with increasing temperature is unknown. Molecular dynamics simulations are used to probe the temperature dependence of the mechanical and nanostructural properties of nanoparticle membranes made of 6 nm diameter Au nanoparticles coated with dodecanethiol ligands and terminated with either methyl (CH 3) or carboxyl (COOH) terminal groups. For methyl-terminated ligands, interactions along the alkane chain provide mechanical stiffness, with a Young's modulus of 1.7 GPa at 300 K. For carboxyl-terminated chains, end-group interactions aremore » significant, producing stiffer membranes at all temperatures, with a Young's modulus of 3.8 GPa at 300 K. For both end-group types, membrane stiffness is reduced to zero at about 400 K. Ligand structure and mechanical properties of membranes at 300 K that have been annealed at 400 K are comparable to samples that do not undergo thermal annealing.« less

Nickel supported on nitrogen-doped carbon nanotubes as hydrogen oxidation reaction catalyst in alkaline electrolyte

DOE PAGES

Zhuang, Zhongbin; Giles, Stephen A.; Zheng, Jie; ...

2016-01-14

The development of a low-cost, high-performance platinum-group-metal-free hydroxide exchange membrane fuel cell is hindered by the lack of a hydrogen oxidation reaction catalyst at the anode. Here we report that a composite catalyst, nickel nanoparticles supported on nitrogen-doped carbon nanotubes, has hydrogen oxidation activity similar to platinum-group metals in alkaline electrolyte. Although nitrogen-doped carbon nanotubes are a very poor hydrogen oxidation catalyst, as a support, it increases the catalytic performance of nickel nanoparticles by a factor of 33 (mass activity) or 21 (exchange current density) relative to unsupported nickel nanoparticles. Density functional theory calculations indicate that the nitrogen-doped support stabilizesmore » the nanoparticle against reconstruction, while nitrogen located at the edge of the nanoparticle tunes local adsorption sites by affecting the d-orbitals of nickel. Here, owing to its high activity and low cost, our catalyst shows significant potential for use in low-cost, high-performance fuel cells.« less

Nickel supported on nitrogen-doped carbon nanotubes as hydrogen oxidation reaction catalyst in alkaline electrolyte

PubMed Central

Zhuang, Zhongbin; Giles, Stephen A.; Zheng, Jie; Jenness, Glen R.; Caratzoulas, Stavros; Vlachos, Dionisios G.; Yan, Yushan

2016-01-01

The development of a low-cost, high-performance platinum-group-metal-free hydroxide exchange membrane fuel cell is hindered by the lack of a hydrogen oxidation reaction catalyst at the anode. Here we report that a composite catalyst, nickel nanoparticles supported on nitrogen-doped carbon nanotubes, has hydrogen oxidation activity similar to platinum-group metals in alkaline electrolyte. Although nitrogen-doped carbon nanotubes are a very poor hydrogen oxidation catalyst, as a support, it increases the catalytic performance of nickel nanoparticles by a factor of 33 (mass activity) or 21 (exchange current density) relative to unsupported nickel nanoparticles. Density functional theory calculations indicate that the nitrogen-doped support stabilizes the nanoparticle against reconstruction, while nitrogen located at the edge of the nanoparticle tunes local adsorption sites by affecting the d-orbitals of nickel. Owing to its high activity and low cost, our catalyst shows significant potential for use in low-cost, high-performance fuel cells. PMID:26762466

Inhibitory effect of zirconium oxide nanoparticles on Candida albicans adhesion to repaired polymethyl methacrylate denture bases and interim removable prostheses: a new approach for denture stomatitis prevention.

PubMed

Gad, Mohammed M; Al-Thobity, Ahmad M; Shahin, Suliman Y; Alsaqer, Badar T; Ali, Aiman A

2017-01-01

Despite drawbacks, cold-cured acrylic resin is still the most common material used in denture repair. Zirconia nanoparticles were among the reinforcements added to increase the strength of the resin. The effect on Candida due to the addition of zirconia nanoparticles to the resin has not been investigated. The aim of this study was to evaluate the effect of zirconia nanoparticles added to cold-cured acrylic resin on Candida albicans adhesion. A total of 120 acrylic resin specimens with dimensions measuring 22×10×2.5 mm 3 were prepared and divided into two equal groups. One group (repair) comprised heat-polymerized specimens that were sectioned at the center and prepared to create a 2 mm repair area that was repaired with cold-cured resin reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. The second group contained intact cold-cured acrylic resin specimens reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. Specimens were incubated at 37°C in artificial saliva containing C. albicans , and the effect of zirconia nanoparticles on C. albicans was assessed using two methods: 1) a slide count method and 2) a direct culture test. Variations in the number of living Candida were observed in relation to the different concentrations of zirconia nanoparticles. Analysis of variance (ANOVA) and post hoc Tukey's tests were performed for data analysis. If the P -value was ≤0.05, then the difference was considered as statistically significant. It was found that C. albicans adhesion to repaired specimens was significantly decreased by the addition of zirconia nanoparticles ( P <0.00001) in comparison with the control group. Intact cold-cured groups and groups repaired with cold-cured resin reinforced with 7.5% wt zirconia nanoparticles showed the lowest Candida count. Tukey's test showed a significant difference between the repaired group and the intact cold-cured group, while the later demonstrated a lower Candida count. The addition of zirconia nanoparticles to cold-cured acrylic resin is an effective method for reducing Candida adhesion to repaired polymethyl methacrylate (PMMA) denture bases and cold-cured removable prosthesis. Based on the results of the current study, zirconia nanoparticles have an antifungal effect, which could be incorporated in the repair material for repairing denture bases and in PMMA removable prostheses as a possible approach for denture stomatitis prevention.

Plasmon-Exciton Interactions Probed Using Spatial Coentrapment of Nanoparticles by Topological Singularities.

PubMed

Ackerman, Paul J; Mundoor, Haridas; Smalyukh, Ivan I; van de Lagemaat, Jao

2015-12-22

We study plasmon-exciton interaction by using topological singularities to spatially confine, selectively deliver, cotrap and optically probe colloidal semiconductor and plasmonic nanoparticles. The interaction is monitored in a single quantum system in the bulk of a liquid crystal medium where nanoparticles are manipulated and nanoconfined far from dielectric interfaces using laser tweezers and topological configurations containing singularities. When quantum dot-in-a-rod particles are spatially colocated with a plasmonic gold nanoburst particle in a topological singularity core, its fluorescence increases because blinking is significantly suppressed and the radiative decay rate increases by nearly an order of magnitude owing to the Purcell effect. We argue that the blinking suppression is the result of the radiative rate change that mitigates Auger recombination and quantum dot ionization, consequently reducing nonradiative recombination. Our work demonstrates that topological singularities are an effective platform for studying and controlling plasmon-exciton interactions.

Plasmon–Exciton Interactions Probed Using Spatial Coentrapment of Nanoparticles by Topological Singularities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ackerman, Paul J.; Mundoor, Haridas; Smalyukh, Ivan I.

2015-12-22

We study plasmon-exciton interaction by using topological singularities to spatially confine, selectively deliver, cotrap and optically probe colloidal semiconductor and plasmonic nanoparticles. The interaction is monitored in a single quantum system in the bulk of a liquid crystal medium where nanoparticles are manipulated and nanoconfined far from dielectric interfaces using laser tweezers and topological configurations containing singularities. When quantum dot-in-a-rod particles are spatially colocated with a plasmonic gold nanoburst particle in a topological singularity core, its fluorescence increases because blinking is significantly suppressed and the radiative decay rate increases by nearly an order of magnitude owing to the Purcell effect.more » We argue that the blinking suppression is the result of the radiative rate change that mitigates Auger recombination and quantum dot ionization, consequently reducing nonradiative recombination. Our work demonstrates that topological singularities are an effective platform for studying and controlling plasmon-exciton interactions.« less

Simple size-controlled synthesis of Au nanoparticles and their size-dependent catalytic activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suchomel, Petr; Kvitek, Libor; Prucek, Robert

The controlled preparation of Au nanoparticles (NPs) in the size range of 6 to 22 nm is explored in this study. The Au NPs were prepared by the reduction of tetrachloroauric acid using maltose in the presence of nonionic surfactant Tween 80 at various concentrations to control the size of the resulting Au NPs. With increasing concentration of Tween 80 a decrease in the size of produced Au NPs was observed, along with a significant decrease in their size distribution. The size-dependent catalytic activity of the synthesized Au NPs was tested in the reduction of 4-nitrophenol with sodium borohydride, resultingmore » in increasing catalytic activity with decreasing size of the prepared nanoparticles. Eley-Rideal catalytic mechanism emerges as the more probable, in contrary to the Langmuir-Hinshelwood mechanism reported for other noble metal nanocatalysts.« less

Simple size-controlled synthesis of Au nanoparticles and their size-dependent catalytic activity

DOE PAGES

Suchomel, Petr; Kvitek, Libor; Prucek, Robert; ...

2018-03-15

The controlled preparation of Au nanoparticles (NPs) in the size range of 6 to 22 nm is explored in this study. The Au NPs were prepared by the reduction of tetrachloroauric acid using maltose in the presence of nonionic surfactant Tween 80 at various concentrations to control the size of the resulting Au NPs. With increasing concentration of Tween 80 a decrease in the size of produced Au NPs was observed, along with a significant decrease in their size distribution. The size-dependent catalytic activity of the synthesized Au NPs was tested in the reduction of 4-nitrophenol with sodium borohydride, resultingmore » in increasing catalytic activity with decreasing size of the prepared nanoparticles. Eley-Rideal catalytic mechanism emerges as the more probable, in contrary to the Langmuir-Hinshelwood mechanism reported for other noble metal nanocatalysts.« less

Curcumin Encapsulated into Methoxy Poly(Ethylene Glycol) Poly(ε-Caprolactone) Nanoparticles Increases Cellular Uptake and Neuroprotective Effect in Glioma Cells.

PubMed

Marslin, Gregory; Sarmento, Bruno Filipe Carmelino Cardoso; Franklin, Gregory; Martins, José Alberto Ribeiro; Silva, Carlos Jorge Ribeiro; Gomes, Andreia Ferreira Castro; Sárria, Marisa Passos; Coutinho, Olga Maria Fernandes Pereira; Dias, Alberto Carlos Pires

2017-03-01

Curcumin is a natural polyphenolic compound isolated from turmeric ( Curcuma longa ) with well-demonstrated neuroprotective and anticancer activities. Although curcumin is safe even at high doses in humans, it exhibits poor bioavailability, mainly due to poor absorption, fast metabolism, and rapid systemic elimination. To overcome these issues, several approaches, such as nanoparticle-mediated targeted delivery, have been undertaken with different degrees of success. The present study was conducted to compare the neuroprotective effect of curcumin encapsulated in poly( ε -caprolactone) and methoxy poly(ethylene glycol) poly( ε -caprolactone) nanoparticles in U251 glioblastoma cells. Prepared nanoparticles were physically characterized by laser doppler anemometry, transmission electron microscopy, and X-ray diffraction. The results from laser doppler anemometry confirmed that the size of poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles ranged between 200-240 nm for poly( ε -caprolactone) nanoparticles and 30-70 nm for poly(ethylene glycol) poly( ε -caprolactone) nanoparticles, and transmission electron microscopy images revealed their spherical shape. Treatment of U251 glioma cells and zebrafish embryos with poly( ε -caprolactone) and poly(ethylene glycol) poly( ε -caprolactone) nanoparticles loaded with curcumin revealed efficient cellular uptake. The cellular uptake of poly(ethylene glycol) poly( ε -caprolactone) nanoparticles was higher in comparison to poly( ε -caprolactone) nanoparticles. Moreover, poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer-loaded curcumin nanoparticles were able to protect the glioma cells against tBHP induced-oxidative damage better than free curcumin. Together, our results show that curcumin-loaded poly(ethylene glycol) poly( ε -caprolactone) di-block copolymer nanoparticles possess significantly stronger neuroprotective effect in U251 human glioma cells compared to free curcumin and curcumin-loaded poly( ε -caprolactone) nanoparticles. Georg Thieme Verlag KG Stuttgart · New York.

Fabrication of self-assembled (-)-epigallocatechin gallate (EGCG) ovalbumin-dextran conjugate nanoparticles and their transport across monolayers of human intestinal epithelial Caco-2 cells.

PubMed

Li, Zheng; Gu, Liwei

2014-02-12

Nanoparticles have the potential to increase bioavailability of nutraceutical compounds such as (-)-epigallocatechin gallate (EGCG). Ovalbumin was conjugated with dextran using the Maillard reaction. The resultant ovalbumin-dextran (O-D) conjugates were self-assembled with EGCG to form EGCG O-D conjugate nanoparticles at pH 5.2 after heating at 80 °C for 60 min. Ovalbumin in EGCG O-D conjugate nanoparticles was further cross-linked by glutaraldehyde for 24 h at room temperature. EGCG O-D conjugate nanoparticles and cross-linked EGCG O-D conjugate nanoparticles in aqueous suspension had particle sizes of 285 and 339 nm, respectively, and showed a spherical morphology. The loading efficiencies of EGCG in these two nanoparticles were 23.4 and 30.0%, whereas the loading capacities were 19.6 and 20.9%, respectively. These nanoparticles showed positive zeta-potentials in a pH range from 2.5 to 4.0 but had negative charges at pH ≥5.0. EGCG O-D conjugate nanoparticles maintained a particle size of 183-349 nm in simulated gastric fluid (SGF) and 188-291 nm in simulated intestinal fluid (SIF) at 37 °C for 2 h, whereas cross-linked nanoparticles had particle sizes of 294-527 nm in SGF and 206-300 nm in SIF. Limited release of EGCG was observed in both nanoparticle systems in simulated gastric and intestinal fluids without and with digestive enzymes. EGCG O-D conjugate nanoparticles significantly enhanced the apparent permeability coefficient (Papp) of EGCG on Caco-2 monolayers compared with EGCG solution, suggesting that these nanoparticles may improve the absorption of EGCG.

In Vitro Cytotoxicity Assessment of an Orthodontic Composite Containing Titanium-dioxide Nano-particles.

PubMed

Heravi, Farzin; Ramezani, Mohammad; Poosti, Maryam; Hosseini, Mohsen; Shajiei, Arezoo; Ahrari, Farzaneh

2013-01-01

Background and aims. Incorporation of nano-particles to orthodontic bonding systems has been considered to prevent enamel demineralization around appliances. This study investigated cytotoxicity of Transbond XT adhesive containing 1 wt% titanium dioxide (TiO2) nano-particles. Materials and methods. Ten composite disks were prepared from each of the conventional and TiO2-containg composites and aged for 1, 3, 5, 7 and 14 days in Dulbecco's Modified Eagle's Medium (DMEM). The extracts were obtained and exposed to culture media of human gingival fibroblasts (HGF) and mouse L929 fibroblasts. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results. Both adhesives were moderately toxic for HGF cells on the first day of the experiment, but the TiO2-containing adhesive produced significantly lower toxicity than the pure adhesive (P<0.05). No significant differences were found in cell viability percentages between the two groups on the other days (P>0.05). There was a significant reduction in cell toxicity with increasing pre-incubation time (P<0.001). L929 cells showed similar toxicity trends, but lower sensitivity to detect cytotoxicity of dental composites. Conclusion. The orthodontic adhesive containing TiO2 nano-particles indicated comparable or even lower toxicity than its nano-particle-free counterpart, indicating that incorporation of 1 wt% TiO2 nano-particles to the composite structure does not result in additional health hazards compared to that occurring with the pure adhesive.

Biogenic nanoparticles bearing antibacterial activity and their synergistic effect with broad spectrum antibiotics: Emerging strategy to combat drug resistant pathogens.

PubMed

Baker, Syed; Pasha, Azmath; Satish, Sreedharamurthy

2017-01-01

The present study emphasizes on synthesis of bimetallic silver-gold nanoparticles from cell free supernatant of Pseudomonas veronii strain AS41G inhabiting Annona squamosa L. The synthesized nanoparticles were characterized using hyphenated techniques with UV-Visible spectra ascertained absorbance peak between 400 and 800 nm. Possible interaction of biomolecules in mediating and stabilization of nanoparticles was depicted with Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) displayed Bragg's peak conferring the 1 0 0, 1 1 1, 2 0 0, and 2 2 0 facets of the face centered cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. Size and shape of the nanoparticles were determined using Transmission electron microscopy (TEM) microgram with size ranging from 5 to 50 nm forming myriad shapes. Antibacterial activity of nanoparticles against significant human pathogens was conferred with well diffusion assay and its synergistic effect with standard antibiotics revealed 87.5% fold increased activity with antibiotic "bacitracin" against bacitracin resistant strains Bacillus subtilis , Escherichia coli and Klebsiella pneumoniae followed by kanamycin with 18.5%, gentamicin with 11.15%, streptomycin with 10%, erythromycin with 9.7% and chloramphenicol with 9.4%. Thus the study concludes with biogenic and ecofriendly route for synthesizing nanoparticles with antibacterial activity against drug resistant pathogens and attributes growing interest on endophytes as an emerging source for synthesis of nanoparticles.

Heteroagglomeration of zinc oxide nanoparticles with clay mineral modulates the bioavailability and toxicity of nanoparticle in Tetrahymena pyriformis.

PubMed

Gupta, Govind Sharan; Senapati, Violet Aileen; Dhawan, Alok; Shanker, Rishi

2017-06-01

The extensive use of zinc oxide nanoparticles (ZnO NPs) in cosmetics, sunscreens and healthcare products increases their release in the aquatic environment. The present study explored the possible interaction of ZnO NPs with montmorillonite clay minerals in aqueous conditions. An addition of ZnO NPs on clay suspension significantly (p<0.05) increases the hydrodymic size of clay particles from 1652±90nm to 2158±13nm due to heteroagglomeration. The electrokinetic measurements showed a significant (p<0.05) difference in the electrophoretic mobilities of bare (-1.80±0.03μmcm/Vs) and ZnO NPs-clay association (-1.37±0.03μmcm/Vs) that results to the electrostatic interaction between ZnO NPs and clay particles. The attenuated total reflectance Fourier transform infrared spectroscopy analysis of ZnO NPs-clay association demonstrated the binding of ZnO NPs with the Si-O-Al region on the edges of clay particles. The increase in size of ZnO NPs-clay heteroagglomerates further leads to their sedimentation at 24h. Although, the stability of ZnO NPs in the clay suspension was decreased due to heteroagglomeration, but the bioavailability and toxicity of ZnO NPs-clay heteroagglomerates in Tetrahymena pyriformis was enhanced. These observations provide an evidence on possible mechanisms available in natural environment that can facilitate nanoparticles entry into the organisms present in lower trophic levels of the food web. Copyright © 2017 Elsevier Inc. All rights reserved.

Direct-writing of copper-based micropatterns on polymer substrates using femtosecond laser reduction of copper (II) oxide nanoparticles

NASA Astrophysics Data System (ADS)

Mizoshiri, Mizue; Ito, Yasuaki; Sakurai, Junpei; Hata, Seiichi

2017-04-01

Copper (Cu)-based micropatterns were fabricated on polymer substrates using femtosecond laser reduction of copper (II) oxide (CuO) nanoparticles. CuO nanoparticle solution, which consisted of CuO nanoparticles, ethylene glycol as a reductant agent, and polyvinylpyrrolidone as a dispersant, was spin-coated on poly(dimethylsiloxane) (PDMS) substrates and was irradiated by focused femtosecond laser pulses to fabricate Cu-based micropatterns. When the laser pulses were raster-scanned onto the solution, CuO nanoparticles were reduced and sintered. Cu-rich and copper (I)-oxide (Cu2O)-rich micropatterns were formed at laser scanning speeds of 15 mm/s and 0.5 mm/s, respectively, and at a pulse energy of 0.54 nJ. Cu-rich electrically conductive micropatterns were obtained without significant damages on the substrates. On the other hand, Cu2O-rich micropatterns exhibited no electrical conductivity, indicating that microcracks were generated on the micropatterns by thermal expansion and shrinking of the substrates. We demonstrated a direct-writing of Cu-rich micro-temperature sensors on PDMS substrates using the foregoing laser irradiation condition. The resistance of the fabricated sensors increased with increasing temperature, which is consistent with that of Cu. This direct-writing technique is useful for fabricating Cu-polymer composite microstructures.

Microglial Immune Response to Low Concentrations of Combustion-Generated Nanoparticles: An In Vitro Model of Brain Health

PubMed Central

Duffy, Cayla M.; Swanson, Jacob; Northrop, William; Nixon, Joshua P.; Butterick, Tammy A.

2018-01-01

The brain is the central regulator for integration and control of responses to environmental cues. Previous studies suggest that air pollution may directly impact brain health by triggering the onset of chronic neuroinflammation. We hypothesize that nanoparticle components of combustion-generated air pollution may underlie these effects. To test this association, a microglial in vitro biological sensor model was used for testing neuroinflammatory response caused by low-dose nanoparticle exposure. The model was first validated using 20 nm silver nanoparticles (AgNP). Next, neuroinflammatory response was tested after exposure to size-selected 20 nm combustion-generated nanoparticles (CGNP) collected from a modern diesel engine. We show that low concentrations of CGNPs promote low-grade inflammatory response indicated by increased pro-inflammatory cytokine release (tumor necrosis factor-α), similar to that observed after AgNP exposure. We also demonstrate increased production of reactive oxygen species and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 phosphorylation in microglia after CGNP stimulation. Finally, we show conditioned media from CGNP-stimulated microglia significantly reduced hypothalamic neuronal survival in vitro. To our knowledge, this data show for the first time that exposure to AgNP and CGNP elicits microglial neuroinflammatory response through the activation of NF-κB. PMID:29522448

Synthesis and characterization of a multifunctional gold-doxorubicin nanoparticle system for pH triggered intracellular anticancer drug release.

PubMed

Khutale, Ganesh V; Casey, Alan

2017-10-01

A nanoparticle drug carrier system has been developed to alter the cellular uptake and chemotherapeutic performance of an available chemotherapeutic drug. The system comprises of a multifunctional gold nanoparticle based drug delivery system (Au-PEG-PAMAM-DOX) as a novel platform for intracellular delivery of doxorubicin (DOX). Spherical gold nanoparticles were synthesized by a gold chloride reduction, stabilized with thiolated polyethylene glycol (PEG) and then covalently coupled with a polyamidoamine (PAMAM) G4 dendrimer. Further, conjugation of an anti-cancer drug doxorubicin to the dendrimer via amide bond resulted in Au-PEG-PAMAM-DOX drug delivery system. Acellular drug release studies proved that DOX released from Au-PEG-PAMAM-DOX at physiological pH was negligible but it was significantly increased at a weak acidic milieu. The intracellular drug release was monitored with confocal laser scanning microscopy analysis. In vitro viability studies showed an increase in the associated doxorubicin cytotoxicity not attributed to carrier components indicating the efficiency of the doxorubicin was improved, upon conjugation to the nano system. As such it is postulated that the developed pH triggered multifunctional doxorubicin-gold nanoparticle system, could lead to a promising platform for intracellular delivery of variety of anticancer drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Long-term bioavailability of redox nanoparticles effectively reduces organ dysfunctions and death in whole-body irradiated mice.

PubMed

Feliciano, Chitho P; Tsuboi, Koji; Suzuki, Kenshi; Kimura, Hiroyuki; Nagasaki, Yukio

2017-06-01

Radioprotective agents have been developed to protect patients against the damaging and lethal effects of ionizing radiation. However, in addition to the intrinsic ability to target reactive oxygen species (ROS), the ability to retain a significant level of bioavailability is desirable in radioprotective agents because that would increase and prolong their radioprotective efficacy and improve its safety. Here, we report the development of a novel nanoparticle-based radioprotective agent with improved bioavailability, which suppressed the adverse effects typically associated with low-molecular-weight (LMW) antioxidants. We developed biocompatible and colloidally stable nanoparticles in which nitroxide radicals that were covalently conjugated (redox nanoparticles, RNP N ) effectively scavenged radiation-induced ROS with a characteristically prolonged bioavailability and tissue-residence time compared with that of conventional LMW antioxidants. The confinement of the nitroxide radicals in the RNP N core prevented its rapid metabolism and excretion out of the body. The nano-sized formulation prevented internalization of RNP N in healthy cells, thereby preserving the normal function of the redox reactions in the cell. This improved pharmacological performance dramatically reduced the radiation-induced organ dysfunctions and increased the survival time of the lethally irradiated mice when the nanoparticles were administered 3-24 h before whole-body irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Static magnetic field reduced exogenous oligonucleotide uptake by spermatozoa using magnetic nanoparticle gene delivery system

NASA Astrophysics Data System (ADS)

Katebi, Samira; Esmaeili, Abolghasem; Ghaedi, Kamran

2016-03-01

Spermatozoa could introduce exogenous oligonucleotides of interest to the oocyte. The most important reason of low efficiency of sperm mediated gene transfer (SMGT) is low uptake of exogenous DNA by spermatozoa. The aim of this study was to evaluate the effects of static magnetic field on exogenous oligonucleotide uptake of spermatozoa using magnetofection method. Magnetic nanoparticles (MNPs) associated with the labeled oligonucleotides were used to increase the efficiency of exogenous oligonucleotide uptake by rooster spermatozoa. We used high-field/high-gradient magnet (NdFeB) to enhance and accelerate exogenous DNA sedimentation at the spermatozoa surface. Flow cytometry analysis was performed to measure viability and percentage of exogenous oligonucleotide uptake by sperm. Flow cytometry analysis showed a significant increase in exogenous oligonucleotide uptake by rooster spermatozoa (P<0.001) when spermatozoa were incubated in exogenous oligonucleotide solution and MNPs. However, by applying static magnetic field during magnetofection method, a significant decrease in exogenous oligonucleotide uptake was observed (P<0.05). Findings of this study showed that MNPs were effective to increase exogenous oligonucleotide uptake by rooster spermatozoa; however unlike others studies, static magnetic field, was not only ineffective to enhance exogenous oligonucleotide uptake by rooster spermatozoa but also led to reduction in efficiency of magnetic nanoparticles in gene transfer.

Development of Multifunctional Nanoparticles for Targeted Drug Delivery and Non-invasive Imaging of Therapeutic Effect

PubMed Central

Sajja, Hari Krishna; East, Michael P.; Mao, Hui; Wang, Andrew Y.; Nie, Shuming; Yang, Lily

2011-01-01

Nanotechnology is a multidisciplinary scientific field undergoing explosive development. Nanometer-sized particles offer novel structural, optical and electronic properties that are not attainable with individual molecules or bulk solids. Advances in nanomedicine can be made by engineering biodegradable nanoparticles such as magnetic iron oxide nanoparticles, polymers, dendrimers and liposomes that are capable of targeted delivery of both imaging agents and anticancer drugs. This leads toward the concept and possibility of personalized medicine for the potential of early detection of cancer lesions, determination of molecular signatures of the tumor by non-invasive imaging and, most importantly, molecular targeted cancer therapy. Increasing evidence suggests that the nanoparticles, whose surface contains a targeting molecule that binds to receptors highly expressed in tumor cells, can serve as cancer image contrast agents to increase sensitivity and specificity in tumor detection. In comparison with other small molecule contrast agents, the advantage of using nanoparticles is their large surface area and the possibility of surface modifications for further conjugation or encapsulation of large amounts of therapeutic agents. Targeted nanoparticles ferry large doses of therapeutic agents into malignant cells while sparing the normal healthy cells. Such multifunctional nanodevices hold the promise of significant improvement of current clinical management of cancer patients. This review explores the development of nanoparticles for enabling and improving the targeted delivery of therapeutic agents, the potential of nanomedicine, and the development of novel and more effective diagnostic and screening techniques to extend the limits of molecular diagnostics providing point-of-care diagnosis and more personalized medicine. PMID:19275541

Gold nanoparticle-enabled blood test for early stage cancer detection and risk assessment.

PubMed

Zheng, Tianyu; Pierre-Pierre, Nickisha; Yan, Xin; Huo, Qun; Almodovar, Alvin J O; Valerio, Felipe; Rivera-Ramirez, Inoel; Griffith, Elizabeth; Decker, David D; Chen, Sixue; Zhu, Ning

2015-04-01

When citrate ligands-capped gold nanoparticles are mixed with blood sera, a protein corona is formed on the nanoparticle surface due to the adsorption of various proteins in the blood to the nanoparticles. Using a two-step gold nanoparticle-enabled dynamic light scattering assay, we discovered that the amount of human immunoglobulin G (IgG) in the gold nanoparticle protein corona is increased in prostate cancer patients compared to noncancer controls. Two pilot studies conducted on blood serum samples collected at Florida Hospital and obtained from Prostate Cancer Biorespository Network (PCBN) revealed that the test has a 90-95% specificity and 50% sensitivity in detecting early stage prostate cancer, representing a significant improvement over the current PSA test. The increased amount of human IgG found in the protein corona is believed to be associated with the autoantibodies produced in cancer patients as part of the immunodefense against tumor. Proteomic analysis of the nanoparticle protein corona revealed molecular profile differences between cancer and noncancer serum samples. Autoantibodies and natural antibodies produced in cancer patients in response to tumorigenesis have been found and detected in the blood of many cancer types. The test may be applicable for early detection and risk assessment of a broad spectrum of cancer. This new blood test is simple, low cost, requires only a few drops of blood sample, and the results are obtained within minutes. The test is well suited for screening purpose. More extensive studies are being conducted to further evaluate and validate the clinical potential of the new test.

Selective growth of n-type nanoparticles on p-type semiconductors for Z-scheme photocatalysis.

PubMed

Miyauchi, Masahiro; Nukui, Yuuya; Atarashi, Daiki; Sakai, Etsuo

2013-10-09

Nanoparticles of an n-type WO3 semiconductor were segregated on the surface of p-type CaFe2O4 particles by a heterogeneous nucleation process under controlled hydrothermal conditions. By use of this approach, WO3 nanoparticles were selectively deposited on the surface of CaFe2O4, resulting in a significant increase in the photocatalytic reaction rate of the WO3/CaFe2O4 composite for the decomposition of gaseous acetaldehyde under visible-light irradiation. The high visible-light activity of the WO3/CaFe2O4 composite was due to efficient charge recombination through the junctions that formed between the two semiconductors.

Gold nanoparticles: enhanced optical trapping and sensitivity coupled with significant heating.

PubMed

Seol, Yeonee; Carpenter, Amanda E; Perkins, Thomas T

2006-08-15

Gold nanoparticles appear to be superior handles in optical trapping assays. We demonstrate that relatively large gold particles (R(b)=50 nm) indeed yield a sixfold enhancement in trapping efficiency and detection sensitivity as compared to similar-sized polystyrene particles. However, optical absorption by gold at the most common trapping wavelength (1064 nm) induces dramatic heating (266 degrees C/W). We determined this heating by comparing trap stiffness from three different methods in conjunction with detailed modeling. Due to this heating, gold nanoparticles are not useful for temperature-sensitive optical-trapping experiments, but may serve as local molecular heaters. Also, such particles, with their increased detection sensitivity, make excellent probes for certain zero-force biophysical assays.

Design, Synthesis of Novel Lipids as Chemical Permeation Enhancers and Development of Nanoparticle System for Transdermal Drug Delivery

PubMed Central

Shah, Punit P.; Etukala, Jagan Reddy; Vemuri, Adithi; Singh, Mandip

2013-01-01

In the present study, we designed and developed novel lipids that include (Z)-1-(Octadec-9-en-1-yl)-pyrrolidine (Cy5T), 1, 1-Di-((Z)-octadec-9-en-1-yl)pyrrolidin-1-ium iodide (Cy5), (Z)-1-(Octadec-9-en-1-yl)-piperidine (Cy6T), and 1, 1-Di-((Z)-octadec-9-en-1-yl) piperidin-1-ium iodide (Cy6) to enhance the transdermal permeation of some selected drugs. Firstly, we evaluated the transdermal permeation efficacies of these lipids as chemical permeation enhancers in vehicle formulations for melatonin, ß-estradiol, caffeine, α-MSH, and spantide using franz diffusion cells. Among them Cy5 lipid was determined to be the most efficient by increasing the transdermal permeation of melatonin, ß-estradiol, caffeine, α-MSH, and spantide by 1.5 to 3.26-fold more at the epidermal layer and 1.3 to 2.5-fold more at the dermal layer, in comparison to either NMP or OA. Hence we developed a nanoparticle system (cy5 lipid ethanol drug nanoparticles) to evaluate any further improvement in the drug penetration. Cy5 lipid formed uniformly sized nanoparticles ranging from 150–200 nm depending on the type of drug. Further, Cy5 based nanoparticle system significantly (p<0.05) increased the permeation of all the drugs in comparison to the lipid solution and standard permeation enhancers. There were about 1.54 to 22-fold more of drug retained in the dermis for the Cy5 based nanoparticles compared to OA/NMP standard enhancers and 3.87 to 66.67-fold more than lipid solution. In addition, epifluorescent microscopic analysis in rhodamine-PE permeation studies confirmed the superior permeation enhancement of LEDs (detection of fluorescence up to skin depth of 340 μm) more than lipid solution, which revealed fluorescence up to skin depth of only 260 μm. In summary the present findings demonstrate that i) cationic lipid with 5 membered amine heterocyclic ring has higher permeating efficacy than the 6 membered amine hertocyclic ring. ii) The nanoparticle system prepared with Cy5 showed significant (p<0.05) increase in the permeation of the drugs than the control penetration enhancers, oleic acid and NMP. PMID:24349315

Oral nanotherapeutics: Redox nanoparticles attenuate ultraviolet B radiation-induced skin inflammatory disorders in Kud:Hr- hairless mice.

PubMed

Feliciano, Chitho P; Nagasaki, Yukio

2017-10-01

The active participation of an anti-inflammatory drug in the biological pathways of inflammation is crucial for the achievement of beneficial and therapeutic effects. This study demonstrated the development of redox nanoparticles that can circulate in the blood at significantly high levels, thus increasing their efficacy as an oral treatment against the deleterious effects of reactive oxygen species (ROS) in an in vivo inflammatory skin model. To confirm the blood bioavailability of the nanoparticles, mice were injected with the nanoparticles solution (RNP N ) via oral gavage. Using electron spin resonance and radioactive labeling techniques, the blood circulation of the redox polymer that forms the nanoparticles was confirmed 24 h after oral administration. This contrasted with its low molecular weight counterpart (NH 2 -TEMPO), which peaked 15 min post injection and was found to be cleared rapidly within minutes after the peak. We then tested its efficacy in the inflammatory skin model. Kud:Hr-hairless mice were irradiated with UVB (302 nm) to induce skin damage and inflammation. Throughout the entire period of UVB irradiation, RNP N was administered to mice by free drinking. NH 2 -TEMPO was used as the control. The results showed that oral supplementation of RNP N significantly improved the therapeutic effects of the core nitroxide radical compared with its low molecular weight counterpart. Furthermore, RNP N significantly reduced UVB-induced skin aging, epidermal thickening, edema, erythema, skin lesions, and various pathological skin inflammatory disorders in vivo. From the obtained data, we concluded that the use of long-circulating redox nanoparticles (RNP N ) provided an effective treatment against the damaging effects of excessive ROS in the body. Copyright © 2017 Elsevier Ltd. All rights reserved.

Retro-inverso d-peptide-modified hyaluronic acid/bioreducible hyperbranched poly(amido amine)/pDNA core-shell ternary nanoparticles for the dual-targeted delivery of short hairpin RNA-encoding plasmids.

PubMed

Gu, Jijin; Chen, Xinyi; Fang, Xiaoling; Sha, Xianyi

2017-07-15

The active targeting of gene carriers is a powerful strategy for improving tumour-specific delivery and therapy. Although numerous l-peptide ligands play significant roles in the active targeting of nanomedicine, retro-inverso d-peptides have been explored as targeting ligands due to their superior stability and bioactivity in vivo. In this study, retro-inverso d-peptide (RIF7)-modified hyaluronic acid (HA)/bioreducible hyperbranched poly(amido amine) (RHB)/plasmid DNA (pDNA) ternary nanoparticles were successfully developed using the layer-by-layer method for the CD44-positive tumour-specific delivery of short hairpin RNA (shRNA)-encoding pDNA through the combination of the Anxa1 (tumour vasculature) and CD44 (tumour cell-surface) receptors, which mediated the dual targeting. The potential of these newly designed nanoparticles was evaluated by examining the efficacy of their cellular uptake and transfection in cell monolayers, tumour spheroids, and malignant xenograft animal models. With negligible cytotoxicity, the spherical-shaped RIF7-HA/RHB/pDNA nanoparticles were the direct result of an electrostatic complex that had efficiently targeted CD44-positive tumour delivery, penetration, and cellular uptake in vitro. The nanoparticles showed excellent target-specific gene transfection even in the presence of serum. The in vivo therapeutic effect of RIF7-HA/RHB/pDNA-shRNA nanoparticle-mediated shRNA targeting of the Cyclin gene (shCyclin) was evaluated in tumour-bearing mice. The RIF7-HA/RHB/pDNA-shCyclin nanoparticles significantly increased the survival time of tumour-bearing mice and substantially reduced tumour growth due to their extremely specific tumour-targeting activity. These results suggested that the combination of HA and retro-inverso peptide RIF7 significantly increased the therapeutic effect of pDNA-shCyclin-loaded nanoparticles for CD44-positive tumours. Thus, RIF7-HA-mediated multi-target ternary gene vectors are an efficient and promising strategy for the delivery of pDNA-shRNA in the targeted treatment of malignant and metastatic cancers. Although l-peptide ligands play significant roles in the active targeting of nanomedicine, retro-inverso d-peptides have been explored as targeting ligands due to their superior stability and bioactivity in vivo. Retro-inverso peptide RIF7 was designed as a ligand of Anxa1 receptor. The resultant peptide, RIF7, displayed high binding efficiency within Anxa1 receptor, which is highly expressed tumour vasculature cells and some tumour cells such as B16F10 and U87MG cells. The most important feature of RIF7 is its high stability in the blood, which is suitable and promising for application in vivo. Multifunctional RIF7-HA was then synthesized by conjugating the RIF7 peptide to HA, which was used to modify the surface of RHB/pDNA nanoparticles to prepare RIF7-HA/RHB/pDNA core-shell ternary nanoparticles for the dual-targeted delivery of shRNA-encoding plasmids in vitro and in vivo. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Preparation of Chitosan Nanoparticles: A Study of Influencing Factors

NASA Astrophysics Data System (ADS)

Thakur, Anupama; Taranjit

2011-12-01

Chitosan (CS), a cationic polysaccharide, offers great advantages for ionic interactions with negatively charged species such as sodium tripolyphosphate (STPP) leading to the formation of biocompatible crosslinked chitosan nanoparticles In the present work, an attempt has been made to systematically study the following factors influencing the ionotropic gelation of chitosan with STPP to produce CS nanoparticles: effect of pH of solution, CS concentration, STPP concentration and CS/STPP ratio. The results show that with the increase in CS concentration, the yield of the nanoparticle decreases whereas size increases. The mean size of the prepared nanoparticles varied between 120 to 720 nm and zeta potential between +14 mV to +53 mV . Nanoparticle size and yield was found to be strongly dependent on solution pH. Nanoparticle size decreased with increase in solution pH from 4 to 5 and yield was found to be maximum at pH = 5. With increase in STPP concentration, the size and yield of the nanoparticle increased. The potential of CS nanoparticles to trap amoxicillin trihydrate, taken as the model drug, was also studied. The maximum drug loading capacity was found to be 35% at a solution pH = 5 for 0.2% CS and 0.086% STPP.

Transient extracellular application of gold nanostars increases hippocampal neuronal activity.

PubMed

Salinas, Kirstie; Kereselidze, Zurab; DeLuna, Frank; Peralta, Xomalin G; Santamaria, Fidel

2014-08-20

With the increased use of nanoparticles in biomedical applications there is a growing need to understand the effects that nanoparticles may have on cell function. Identifying these effects and understanding the mechanism through which nanoparticles interfere with the normal functioning of a cell is necessary for any therapeutic or diagnostic application. The aim of this study is to evaluate if gold nanoparticles can affect the normal function of neurons, namely their activity and coding properties. We synthesized star shaped gold nanoparticles of 180 nm average size. We applied the nanoparticles to acute mouse hippocampal slices while recording the action potentials from single neurons in the CA3 region. Our results show that CA3 hippocampal neurons increase their firing rate by 17% after the application of gold nanostars. The increase in excitability lasted for as much as 50 minutes after a transient 5 min application of the nanoparticles. Further analyses of the action potential shape and computational modeling suggest that nanoparticles block potassium channels responsible for the repolarization of the action potentials, thus allowing the cell to increase its firing rate. Our results show that gold nanoparticles can affect the coding properties of neurons by modifying their excitability.

Cell type-dependent uptake, localization, and cytotoxicity of 1.9 nm gold nanoparticles

PubMed Central

Coulter, Jonathan A; Jain, Suneil; Butterworth, Karl T; Taggart, Laura E; Dickson, Glenn R; McMahon, Stephen J; Hyland, Wendy B; Muir, Mark F; Trainor, Coleman; Hounsell, Alan R; O’Sullivan, Joe M; Schettino, Giuseppe; Currell, Fred J; Hirst, David G; Prise, Kevin M

2012-01-01

Background This follow-up study aims to determine the physical parameters which govern the differential radiosensitization capacity of two tumor cell lines and one immortalized normal cell line to 1.9 nm gold nanoparticles. In addition to comparing the uptake potential, localization, and cytotoxicity of 1.9 nm gold nanoparticles, the current study also draws on comparisons between nanoparticle size and total nanoparticle uptake based on previously published data. Methods We quantified gold nanoparticle uptake using atomic emission spectroscopy and imaged intracellular localization by transmission electron microscopy. Cell growth delay and clonogenic assays were used to determine cytotoxicity and radiosensitization potential, respectively. Mechanistic data were obtained by Western blot, flow cytometry, and assays for reactive oxygen species. Results Gold nanoparticle uptake was preferentially observed in tumor cells, resulting in an increased expression of cleaved caspase proteins and an accumulation of cells in sub G1 phase. Despite this, gold nanoparticle cytotoxicity remained low, with immortalized normal cells exhibiting an LD50 concentration approximately 14 times higher than tumor cells. The surviving fraction for gold nanoparticle-treated cells at 3 Gy compared with that of untreated control cells indicated a strong dependence on cell type in respect to radiosensitization potential. Conclusion Gold nanoparticles were most avidly endocytosed and localized within cytoplasmic vesicles during the first 6 hours of exposure. The lack of significant cytotoxicity in the absence of radiation, and the generation of gold nanoparticle-induced reactive oxygen species provide a potential mechanism for previously reported radiosensitization at megavoltage energies. PMID:22701316

Lattice-patterned LC-polymer composites containing various nanoparticles as additives

PubMed Central

2012-01-01

In this study, we show the effect of various nanoparticle additives on phase separation behavior of a lattice-patterned liquid crystal [LC]-polymer composite system and on interfacial properties between the LC and polymer. Lattice-patterned LC-polymer composites were fabricated by exposing to UV light a mixture of a prepolymer, an LC, and SiO2 nanoparticles positioned under a patterned photomask. This resulted in the formation of an LC and prepolymer region through phase separation. We found that the incorporation of SiO2 nanoparticles significantly affected the electro-optical properties of the lattice-patterned LC-polymer composites. This effect is a fundamental characteristic of flexible displays. The electro-optical properties depend on the size and surface functional groups of the SiO2 nanoparticles. Compared with untreated pristine SiO2 nanoparticles, which adversely affect the performance of LC molecules surrounded by polymer walls, SiO2 nanoparticles with surface functional groups were found to improve the electro-optical properties of the lattice-patterned LC-polymer composites by increasing the quantity of SiO2 nanoparticles. The surface functional groups of the SiO2 nanoparticles were closely related to the distribution of SiO2 nanoparticles in the LC-polymer composites, and they influenced the electro-optical properties of the LC molecules. It is clear from our work that the introduction of nanoparticles into a lattice-patterned LC-polymer composite provides a method for controlling and improving the composite's electro-optical properties. This technique can be used to produce flexible substrates for various flexible electronic devices. PMID:22222011

Fate and risks of nanomaterials in aquatic and terrestrial environments.

PubMed

Batley, Graeme E; Kirby, Jason K; McLaughlin, Michael J

2013-03-19

Over the last decade, nanoparticles have been used more frequently in industrial applications and in consumer and medical products, and these applications of nanoparticles will likely continue to increase. Concerns about the environmental fate and effects of these materials have stimulated studies to predict environmental concentrations in air, water, and soils and to determine threshold concentrations for their ecotoxicological effects on aquatic or terrestrial biota. Nanoparticles can be added to soils directly in fertilizers orplant protection products or indirectly through application to land or wastewater treatment products such as sludges or biosolids. Nanoparticles may enter aquatic systems directly through industrial discharges or from disposal of wastewater treatment effluents or indirectly through surface runoff from soils. Researchers have used laboratory experiments to begin to understand the effects of nanoparticles on waters and soils, and this Account reviews that research and the translation of those results to natural conditions. In the environment, nanoparticles can undergo a number of potential transformations that depend on the properties both of the nanoparticle and of the receiving medium. These transformations largely involve chemical and physical processes, but they can involve biodegradation of surface coatings used to stabilize many nanomaterial formulations. The toxicity of nanomaterials to algae involves adsorption to cell surfaces and disruption to membrane transport. Higher organisms can directly ingest nanoparticles, and within the food web, both aquatic and terrestrial organisms can accumulate nanoparticles. The dissolution of nanoparticles may release potentially toxic components into the environment. Aggregation with other nanoparticles (homoaggregation) or with natural mineral and organic colloids (heteroaggregation) will dramatically change their fate and potential toxicity in the environment. Soluble natural organic matter may interact with nanoparticles to change surface charge and mobility and affect the interactions of those nanoparticles with biota. Ultimately, aquatic nanomaterials accumulate in bottom sediments, facilitated in natural systems by heteroaggregation. Homoaggregates of nanoparticles sediment more slowly. Nanomaterials from urban, medical, and industrial sources may undergo significant transformations during wastewater treatment processes. For example, sulfidation of silver nanoparticles in wastewater treatment systems converts most of the nanoparticles to silver sulfides (Ag₂S). Aggregation of the nanomaterials with other mineral and organic components of the wastewater often results in most of the nanomaterial being associated with other solids rather than remaining as dispersed nanosized suspensions. Risk assessments for nanomaterial releases to the environment are still in their infancy, and reliable measurements of nanomaterials at environmental concentrations remain challenging. Predicted environmental concentrations based on current usage are low but are expected to increase as use increases. At this early stage, comparisons of estimated exposure data with known toxicity data indicate that the predicted environmental concentrations are orders of magnitude below those known to have environmental effects on biota. As more toxicity data are generated under environmentally-relevant conditions, risk assessments for nanomaterials will improve to produce accurate assessments that assure environmental safety.

Quantification of Functionalised Gold Nanoparticle-Targeted Knockdown of Gene Expression in HeLa Cells

PubMed Central

Jiwaji, Meesbah; Sandison, Mairi E.; Reboud, Julien; Stevenson, Ross; Daly, Rónán; Barkess, Gráinne; Faulds, Karen; Kolch, Walter; Graham, Duncan; Girolami, Mark A.; Cooper, Jonathan M.; Pitt, Andrew R.

2014-01-01

Introduction Gene therapy continues to grow as an important area of research, primarily because of its potential in the treatment of disease. One significant area where there is a need for better understanding is in improving the efficiency of oligonucleotide delivery to the cell and indeed, following delivery, the characterization of the effects on the cell. Methods In this report, we compare different transfection reagents as delivery vehicles for gold nanoparticles functionalized with DNA oligonucleotides, and quantify their relative transfection efficiencies. The inhibitory properties of small interfering RNA (siRNA), single-stranded RNA (ssRNA) and single-stranded DNA (ssDNA) sequences targeted to human metallothionein hMT-IIa are also quantified in HeLa cells. Techniques used in this study include fluorescence and confocal microscopy, qPCR and Western analysis. Findings We show that the use of transfection reagents does significantly increase nanoparticle transfection efficiencies. Furthermore, siRNA, ssRNA and ssDNA sequences all have comparable inhibitory properties to ssDNA sequences immobilized onto gold nanoparticles. We also show that functionalized gold nanoparticles can co-localize with autophagosomes and illustrate other factors that can affect data collection and interpretation when performing studies with functionalized nanoparticles. Conclusions The desired outcome for biological knockdown studies is the efficient reduction of a specific target; which we demonstrate by using ssDNA inhibitory sequences targeted to human metallothionein IIa gene transcripts that result in the knockdown of both the mRNA transcript and the target protein. PMID:24926959

A 13-week repeated-dose oral toxicity and bioaccumulation of aluminum oxide nanoparticles in mice.

PubMed

Park, Eun-Jung; Sim, Jaehoon; Kim, Younghun; Han, Beom Seok; Yoon, Cheolho; Lee, Somin; Cho, Myung-Haing; Lee, Byoung-Seok; Kim, Jae-Ho

2015-03-01

Because of an increase in the commercial applications of manufactured nanoparticles, the issue of potential adverse health effects of nanoparticles following intended or unintended exposure is rapidly gaining attention. In this study, we evaluated the toxicity of aluminum oxide nanoparticles (AlNPs, rod-type, 1.5, 3, and 6 mg/kg) after oral administration to mice for 13 weeks. Compared with the control group, the consumption of diet and drinking water and body weight gain decreased in the group treated with AlNPs. The group treated with 6 mg/kg AlNPs also showed a marked elevation in the count of white blood cells that associated with a significant decrease and increase to the proportion of eosinophils and lymphocytes, respectively. In addition, the secretion of IL-6 and monocyte chemotactic protein-1 increased in a dose-dependent manner in the treated groups. Furthermore, AlNPs showed the highest accumulation in the liver and kidneys compared with the control group, increased the lactate dehydrogenase level in the blood, and induced the development of a pathological lesion in the liver and kidneys. Taken together, we suggest that the target organs of rod-type AlNPs may be the liver, kidneys and the immune system, and the not-observed adverse effect level may be lower than 6 mg/kg.

The Protein Corona around Nanoparticles Facilitates Stem Cell Labeling for Clinical MR Imaging.

PubMed

Nejadnik, Hossein; Taghavi-Garmestani, Seyed-Meghdad; Madsen, Steven J; Li, Kai; Zanganeh, Saeid; Yang, Phillip; Mahmoudi, Morteza; Daldrup-Link, Heike E

2018-03-01

Purpose To evaluate if the formation of a protein corona around ferumoxytol nanoparticles can facilitate stem cell labeling for in vivo tracking with magnetic resonance (MR) imaging. Materials and Methods Ferumoxytol was incubated in media containing human serum (group 1), fetal bovine serum (group 2), StemPro medium (group 3), protamine (group 4), and protamine plus heparin (group 5). Formation of a protein corona was characterized by means of dynamic light scattering, ζ potential, and liquid chromatography-mass spectrometry. Iron uptake was evaluated with 3,3'-diaminobenzidine-Prussian blue staining, lysosomal staining, and inductively coupled plasma spectrometry. To evaluate the effect of a protein corona on stem cell labeling, human mesenchymal stem cells (hMSCs) were labeled with the above formulations, implanted into pig knee specimens, and investigated with T2-weighted fast spin-echo and multiecho spin-echo sequences on a 3.0-T MR imaging unit. Data in different groups were compared by using a Kruskal-Wallis test. Results Compared with bare nanoparticles, all experimental groups showed significantly increased negative ζ values (from -37 to less than -10; P = .008). Nanoparticles in groups 1-3 showed an increased size because of the formation of a protein corona. hMSCs labeled with group 1-5 media showed significantly shortened T2 relaxation times compared with unlabeled control cells (P = .0012). hMSCs labeled with group 3 and 5 media had the highest iron uptake after cells labeled with group 1 medium. After implantation into pig knees, hMSCs labeled with group 1 medium showed significantly shorter T2 relaxation times than hMSCs labeled with group 2-5 media (P = .0022). Conclusion The protein corona around ferumoxytol nanoparticles can facilitate stem cell labeling for clinical cell tracking with MR imaging. © RSNA, 2017 Online supplemental material is available for this article.

Increased cellular uptake of peptide-modified PEGylated gold nanoparticles.

PubMed

He, Bo; Yang, Dan; Qin, Mengmeng; Zhang, Yuan; He, Bing; Dai, Wenbing; Wang, Xueqing; Zhang, Qiang; Zhang, Hua; Yin, Changcheng

2017-12-09

Gold nanoparticles are promising drug delivery vehicles for nucleic acids, small molecules, and proteins, allowing various modifications on the particle surface. However, the instability and low bioavailability of gold nanoparticles compromise their clinical application. Here, we functionalized gold nanoparticles with CPP fragments (CALNNPFVYLI, CALRRRRRRRR) through sulfhydryl PEG to increase their stability and bioavailability. The resulting gold nanoparticles were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible spectrometry and X-ray photoelectron spectroscopy (XPS), and the stability in biological solutions was evaluated. Comparing to PEGylated gold nanoparticles, CPP (CALNNPFVYLI, CALRRRRRRRR)-modified gold nanoparticles showed 46 folds increase in cellular uptake in A549 and B16 cell lines, as evidenced by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). The interactions between gold nanoparticles and liposomes indicated CPP-modified gold nanoparticles bind to cell membrane more effectively than PEGylated gold nanoparticles. Surface plasmon resonance (SPR) was used to measure interactions between nanoparticles and the membrane. TEM and uptake inhibitor experiments indicated that the cellular entry of gold nanoparticles was mediated by clathrin and macropinocytosis. Other energy independent endocytosis pathways were also identified. Our work revealed a new strategy to modify gold nanoparticles with CPP and illustrated the cellular uptake pathway of CPP-modified gold nanoparticles. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of antibody-modified chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier as a strategy for inhibiting HIV replication in astrocytes.

PubMed

Gu, Jijin; Al-Bayati, Karam; Ho, Emmanuel A

2017-08-01

RNA interference (RNAi)-mediated gene silencing offers a novel treatment and prevention strategy for human immunodeficiency virus (HIV) infection. HIV was found to infect and replicate in human brain cells and can cause neuroinfections and neurological deterioration. We designed dual-antibody-modified chitosan/small interfering RNA (siRNA) nanoparticles to deliver siRNA across the blood-brain barrier (BBB) targeting HIV-infected brain astrocytes as a strategy for inhibiting HIV replication. We hypothesized that transferrin antibody and bradykinin B2 antibody could specifically bind to the transferrin receptor (TfR) and bradykinin B2 receptor (B2R), respectively, and deliver siRNA across the BBB into astrocytes as potential targeting ligands. In this study, chitosan nanoparticles (CS-NPs) were prepared by a complex coacervation method in the presence of siRNA, and antibody was chemically conjugated to the nanoparticles. The antibody-modified chitosan nanoparticles (Ab-CS-NPs) were spherical in shape, with an average particle size of 235.7 ± 10.2 nm and a zeta potential of 22.88 ± 1.78 mV. The therapeutic potential of the nanoparticles was evaluated based on their cellular uptake and gene silencing efficiency. Cellular accumulation and gene silencing efficiency of Ab-CS-NPs in astrocytes were significantly improved compared to non-modified CS-NPs and single-antibody-modified CS-NPs. These results suggest that the combination of anti-Tf antibody and anti-B2 antibody significantly increased the knockdown effect of siRNA-loaded nanoparticles. Thus, antibody-mediated dual-targeting nanoparticles are an efficient and promising delivery strategy for inhibiting HIV replication in astrocytes. Graphical abstract Graphic representation of dual-antibody-conjugated chitosan nanoparticles for the targeted delivery of siRNA across the blood-brain barrier (BBB) for inhibiting HIV replication in astrocytes. a Nanoparticle delivery to the BBB and penetration. b TfR-mediated transcytosis of nanoparticles across the epithelial cells. c B2R-mediated endocytosis of nanoparticles in astrocytes. d The molecular interactions between HIV-1 Tat protein and Cyclin T1 and Tip110 cellular proteins. e A schematic representation of chitosan nanoparticles with its components. RNAPII RNA polymerase II, TAR transactivation response RNA element, LTR long terminal repeat, Ab antibody, CS chitosan, TPP tripolyphosphate.

Temperature behavior of the antiferromagnetic susceptibility of nanoferrihydrite from the measurements of the magnetization curves in fields of up to 250 kOe

NASA Astrophysics Data System (ADS)

Balaev, D. A.; Popkov, S. I.; Krasikov, A. A.; Balaev, A. D.; Dubrovskiy, A. A.; Stolyar, S. V.; Yaroslavtsev, R. N.; Ladygina, V. P.; Iskhakov, R. S.

2017-10-01

The cross-breeding problem of the temperature dependence of the antiferromagnetic susceptibility of ferrihydrite nanoparticles is considered. Iron ions Fe3+ in ferrihydrite are ordered antiferromagnetically; however, the existence of defects on the surface and in the bulk of nanoparticles induces a noncompensated magnetic moment that leads to a typical superparamagnetic behavior of ensemble of the nanoparticles with a characteristic blocking temperature. In an unblocked state, magnetization curves of such objects are described as a superposition of the Langevin function and the linear-in-field contribution of the antiferromagnetic "core" of the nanoparticles. According to many studies of the magnetization curves performed on ferrihydrite (and related ferritin) nanoparticles in fields to 60 kOe, dependence χAF( T) decreases as temperature increases, which was related before to the superantiferromagnetism effect. As the magnetic field range increases to 250 kOe, the values of χAF obtained from an analysis of the magnetization curves become lower in magnitude; however, the character of the temperature evolution of χAF is changed: now, dependence χAF( T) is an increasing function. The latter is typical for a system of AF particles with random orientation of the crystallographic axes. To correctly determine the antiferromagnetic susceptibility of AF nanoparticles (at least, ferrihydrite) and to search for effects related to the superantiferromagnetism effect, it is necessary to use in experiments the range of magnetic field significantly higher than that the standard value 60 kOe used in most experiments. The study of the temperature evolution of the magnetization curves shows that the observed crossover is due to the existence of small magnetic moments in the samples.

Formation mechanism of monodispersed spherical core-shell ceria/polymer hybrid nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izu, Noriya, E-mail: n-izu@aist.go.jp; Uchida, Toshio; Matsubara, Ichiro

2011-08-15

Graphical abstract: The formation mechanism for core-shell nanoparticles is considered to be as follows: nucleation and particle growth occur simultaneously (left square); very slow particle growth occurs (middle square). Highlights: {yields} The size of the resultant nanoparticles was strongly and complicatedly dependent on the set temperature used during reflux heating and the PVP molecular weight. {yields} The size of the nanoparticles increased by a 2-step process as the reflux heating time increased. {yields} The IR spectral changes with increasing reflux time indicated the increase in the number of cross-linked polymers in the shell. -- Abstract: Very unique core-shell ceria (ceriummore » oxide)/polymer hybrid nanoparticles that have monodispersed spherical structures and are easily dispersed in water or alcohol without the need for a dispersant were reported recently. The formation mechanism of the unique nanoparticles, however, was not clear. In order to clarify the formation mechanism, these nanoparticles were prepared using a polyol method (reflux heating) under varied conditions of temperature, time, and concentration and molecular weight of added polymer (poly(vinylpyrrolidone)). The size of the resultant nanoparticles was strongly and complicatedly dependent on the set temperature used during reflux heating and the poly(vinylpyrrolidone) molecular weight. Furthermore, the size of the nanoparticles increased by a 2-step process as the reflux heating time increased. The IR spectral changes with increasing reflux time indicated the increase in the number of cross-linked polymers in the shell. From these results, the formation mechanism was discussed and proposed.« less

Modeling the efficiency of a magnetic needle for collecting magnetic cells

NASA Astrophysics Data System (ADS)

Butler, Kimberly S.; Adolphi, Natalie L.; Bryant, H. C.; Lovato, Debbie M.; Larson, Richard S.; Flynn, Edward R.

2014-07-01

As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium.

Modeling the Efficiency of a Magnetic Needle for Collecting Magnetic Cells

PubMed Central

Butler, Kimberly S; Adolphi, Natalie L.; Bryant, H C; Lovato, Debbie M; Larson, Richard S; Flynn, Edward R

2014-01-01

As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in 1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and 2) water in which 3, 5, 10 and 100 % of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency vs. time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium. PMID:24874577

Competition Between Resonant Plasmonic Coupling and Electrostatic Interaction in Reduced Graphene Oxide Quantum Dots.

PubMed

Karna, Sanjay; Mahat, Meg; Choi, Tae-Youl; Shimada, Ryoko; Wang, Zhiming; Neogi, Arup

2016-11-22

The light emission from reduced graphene oxide quantum dots (rGO-QDs) exhibit a significant enhancement in photoluminescence (PL) due to localized surface plasmon (LSP) interactions. Silver and gold nanoparticles (NPs) coupled to rGO nanoparticles exhibit the effect of resonant LSP coupling on the emission processes. Enhancement of the radiative recombination rate in the presence of Ag-NPs induced LSP tuned to the emission energy results in a four-fold increase in PL intensity. The localized field due to the resonantly coupled LSP modes induces n-π* transitions that are not observed in the absence of the resonant interaction of the plasmons with the excitons. An increase in the density of the Ag-NPs result in a detuning of the LSP energy from the emission energy of the nanoparticles. The detuning is due to the cumulative effect of the red-shift in the LSP energy and the electrostatic field induced blue shift in the PL energy of the rGO-QDs. The detuning quenches the PL emission from rGO-QDs at higher concentration of Ag NPs due to non-dissipative effects unlike plasmon induced Joule heating that occurs under resonance conditions. An increase in Au nanoparticles concentration results in an enhancement of PL emission due to electrostatic image charge effect.