A Review of the Structure, Preparation, and Application of NLCs, PNPs, and PLNs

PubMed Central

Li, Qianwen; Cai, Tiange; Huang, Yinghong; Xia, Xi; Cole, Susan P. C.; Cai, Yu

2017-01-01

Nanostructured lipid carriers (NLCs) are modified solid lipid nanoparticles (SLNs) that retain the characteristics of the SLN, improve drug stability and loading capacity, and prevent drug leakage. Polymer nanoparticles (PNPs) are an important component of drug delivery. These nanoparticles can effectively direct drug delivery to specific targets and improve drug stability and controlled drug release. Lipid–polymer nanoparticles (PLNs), a new type of carrier that combines liposomes and polymers, have been employed in recent years. These nanoparticles possess the complementary advantages of PNPs and liposomes. A PLN is composed of a core–shell structure; the polymer core provides a stable structure, and the phospholipid shell offers good biocompatibility. As such, the two components increase the drug encapsulation efficiency rate, facilitate surface modification, and prevent leakage of water-soluble drugs. Hence, we have reviewed the current state of development for the NLCs’, PNPs’, and PLNs’ structures, preparation, and applications over the past five years, to provide the basis for further study on a controlled release drug delivery system. PMID:28554993

Heterogeneous ligand-nanoparticle distributions: a major obstacle to scientific understanding and commercial translation.

PubMed

Mullen, Douglas G; Banaszak Holl, Mark M

2011-11-15

Nanoparticles conjugated with functional ligands are expected to have a major impact in medicine, photonics, sensing, and nanoarchitecture design. One major obstacle to realizing the promise of these materials, however, is the difficulty in controlling the ligand/nanoparticle ratio. This obstacle can be segmented into three key areas: First, many designs of these systems have failed to account for the true heterogeneity of ligand/nanoparticle ratios that compose each material. Second, studies in the field often use the mean ligand/nanoparticle ratio as the accepted level of characterization of these materials. This measure is insufficient because it does not provide information about the distribution of ligand/nanoparticle species within a sample or the number and relative amount of the different species that compose a material. Without these data, researchers do not have an accurate definition of material composition necessary both to understand the material-property relationships and to monitor the consistency of the material. Third, some synthetic approaches now in use may not produce consistent materials because of their sensitivity to reaction kinetics and to the synthetic history of the nanoparticle. In this Account, we describe recent advances that we have made in under standing the material composition of ligand-nanoparticle systems. Our work has been enabled by a model system using poly(amidoamine) dendrimers and two small molecule ligands. Using reverse phase high-pressure liquid chromatography (HPLC), we have successfully resolved and quantified the relative amounts and ratios of each ligand/dendrimer combination. This type of information is rare within the field of ligand-nanoparticle materials because most analytical techniques have been unable to identify the components in the distribution. Our experimental data indicate that the actual distribution of ligand-nanoparticle components is much more heterogeneous than is commonly assumed. The mean ligand/nanoparticle ratio that is typically the only information known about a material is insufficient because the mean does not provide information on the diversity of components in the material and often does not describe the most common component (the mode). Additionally, our experimental data has provided examples of material batches with the same mean ligand/nanoparticle ratio and very different distributions. This discrepancy indicates that the mean cannot be used as the sole metric to assess the reproducibility of a system. We further found that distribution profiles can be highly sensitive to the synthetic history of the starting material as well as slight changes in reaction conditions. We have incorporated the lessons from our experimental data into the design of new ligand-nanoparticle systems to provide improved control over these ratios.

A new view for nanoparticle assemblies: from crystalline to binary cooperative complementarity.

PubMed

Yan, Cong; Wang, Tie

2017-03-06

Studies on nanoparticle assemblies and their applications have been research frontiers in nanoscience in the past few decades and remarkable progress has been made in the synthetic strategies and techniques. Recently, the design and fabrication of the nanoparticle-based nanomaterials or nanodevices with integrated and enhanced properties compared to those of the individual components have gradually become the mainstream. However, a systematic solution to provide a big picture for future development and guide the investigation of different aspects of the study of nanoparticle assemblies remains a challenge. The binary cooperative complementary principle could be an answer. The binary cooperative complementary principle is a universal discipline and can describe the fundamental properties of matter from the subatomic particles to the universe. According to its definition, a variety of nanoparticle assemblies, which represent the cutting-edge work in the nanoparticle studies, are naturally binary cooperative complementary materials. Therefore, the introduction of the binary cooperative complementary principle in the studies of nanoparticle assemblies could provide a unique perspective for reviewing this field and help in the design and fabrication of novel functional nanoparticle assemblies.

ZnO nanoparticles as an efficient, heterogeneous, reusable, and ecofriendly catalyst for four-component one-pot green synthesis of pyranopyrazole derivatives in water.

PubMed

Sachdeva, Harshita; Saroj, Rekha

2013-01-01

An extremely efficient catalytic protocol for the synthesis of a series of pyranopyrazole derivatives developed in a one-pot four-component approach in the presence of ZnO nanoparticles as heterogeneous catalyst using water as a green solvent is reported. Greenness of the process is well instituted as water is exploited both as reaction media and medium for synthesis of catalyst. The ZnO nanoparticles exhibited excellent catalytic activity, and the proposed methodology is capable of providing the desired products in good yield (85-90%) and short reaction time. After reaction course, ZnO nanoparticles can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. All the synthesized compounds have been characterized on the basis of elemental analysis, IR, ¹H NMR, and ¹³C NMR spectral studies.

Nanoparticle-releasing nanofiber composites for enhanced in vivo vaginal retention.

PubMed

Krogstad, Emily A; Ramanathan, Renuka; Nhan, Christina; Kraft, John C; Blakney, Anna K; Cao, Shijie; Ho, Rodney J Y; Woodrow, Kim A

2017-11-01

Current approaches for topical vaginal administration of nanoparticles result in poor retention and extensive leakage. To overcome these challenges, we developed a nanoparticle-releasing nanofiber delivery platform and evaluated its ability to improve nanoparticle retention in a murine model. We individually tailored two components of this drug delivery system for optimal interaction with mucus, designing (1) mucoadhesive fibers for better retention in the vaginal tract, and (2) PEGylated nanoparticles that diffuse quickly through mucus. We hypothesized that this novel dual-functioning (mucoadhesive/mucus-penetrating) composite material would provide enhanced retention of nanoparticles in the vaginal mucosa. Equivalent doses of fluorescent nanoparticles were vaginally administered to mice in either water (aqueous suspension) or fiber composites, and fluorescent content was quantified in cervicovaginal mucus and vaginal tissue at time points from 24 h to 7d. We also fabricated composite fibers containing etravirine-loaded nanoparticles and evaluated the pharmacokinetics over 7d. We found that our composite materials provided approximately 30-fold greater retention of nanoparticles in the reproductive tract at 24 h compared to aqueous suspensions. Compared to nanoparticles in aqueous suspension, the nanoparticles in fiber composites exhibited sustained and higher etravirine concentrations after 24 h and up to 7d, demonstrating the capabilities of this new delivery platform to sustain nanoparticle release out to 3d and drug retention out to one week after a single administration. This is the first report of nanoparticle-releasing fibers for vaginal drug delivery, as well as the first study of a single delivery system that combines two components uniquely engineered for complementary interactions with mucus. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbially-mediated method for synthesis of non-oxide semiconductor nanoparticles

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

Phelps, Tommy J.; Lauf, Robert J.; Moon, Ji-Won

The invention is directed to a method for producing non-oxide semiconductor nanoparticles, the method comprising: (a) subjecting a combination of reaction components to conditions conducive to microbially-mediated formation of non-oxide semiconductor nanoparticles, wherein said combination of reaction components comprises i) anaerobic microbes, ii) a culture medium suitable for sustaining said anaerobic microbes, iii) a metal component comprising at least one type of metal ion, iv) a non-metal component comprising at least one non-metal selected from the group consisting of S, Se, Te, and As, and v) one or more electron donors that provide donatable electrons to said anaerobic microbes duringmore » consumption of the electron donor by said anaerobic microbes; and (b) isolating said non-oxide semiconductor nanoparticles, which contain at least one of said metal ions and at least one of said non-metals. The invention is also directed to non-oxide semiconductor nanoparticle compositions produced as above and having distinctive properties.« less

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

Gelatin modified lipid nanoparticles for anti- viral drug delivery.

PubMed

K S, Joshy; S, Snigdha; Kalarikkal, Nandakumar; Pothen, Laly A; Thomas, Sabu

2017-10-01

The major challenges to clinical application of zidovudine are its moderate aqueous solubility and relative short half-life and serious side effects due to frequent administrations. We investigated the preparation of zidovudine-loaded nanoparticles based on lipids which were further modified with the polymer gelatin. Formulation and stability of the modified nanoparticles were analysed from the physico-chemical characterizations. The interactions of nanoparticles with blood components were tested by haemolysis and aggregation studies. The drug content and entrapment efficiencies were assessed by UV analysis. The effect of nanoparticles on protein adsorption was assessed by native polyacrylamide gel electrophoresis (PAGE). In vitro release studies showed a sustained release profile of zidovudine. In vitro cytotoxicity and cellular uptake of the zidovudine-loaded nanoparticles were performed in MCF-7 and neuro 2a brain cells. The enhanced cellular internalization of drug loaded modified nanoparticles in both the cell lines were revealed by fluorescence microscopy. Hence the present study focuses on the feasibility of zidovudine-loaded polymer modified lipid nanoparticles as carriers for safe and efficient HIV/AIDS therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Thiol-Reactive Star Polymers Display Enhanced Association with Distinct Human Blood Components.

PubMed

Glass, Joshua J; Li, Yang; De Rose, Robert; Johnston, Angus P R; Czuba, Ewa I; Khor, Song Yang; Quinn, John F; Whittaker, Michael R; Davis, Thomas P; Kent, Stephen J

2017-04-12

Directing nanoparticles to specific cell types using nonantibody-based methods is of increasing interest. Thiol-reactive nanoparticles can enhance the efficiency of cargo delivery into specific cells through interactions with cell-surface proteins. However, studies to date using this technique have been largely limited to immortalized cell lines or rodents, and the utility of this technology on primary human cells is unknown. Herein, we used RAFT polymerization to prepare pyridyl disulfide (PDS)-functionalized star polymers with a methoxy-poly(ethylene glycol) brush corona and a fluorescently labeled cross-linked core using an arm-first method. PDS star polymers were examined for their interaction with primary human blood components: six separate white blood cell subsets, as well as red blood cells and platelets. Compared with control star polymers, thiol-reactive nanoparticles displayed enhanced association with white blood cells at 37 °C, particularly the phagocytic monocyte, granulocyte, and dendritic cell subsets. Platelets associated with more PDS than control nanoparticles at both 37 °C and on ice, but they were not activated in the duration examined. Association with red blood cells was minor but still enhanced with PDS nanoparticles. Thiol-reactive nanoparticles represent a useful strategy to target primary human immune cell subsets for improved nanoparticle delivery.

Numerical study of magnetic nanofluids flow in the round channel located in the constant magnetic field

NASA Astrophysics Data System (ADS)

Pryazhnikov, Maxim; Guzei, Dmitriy; Minakov, Andrey; Rodionova, Tatyana

2017-10-01

In this paper, the study of ferromagnetic nanoparticles behaviour in the constant magnetic field is carried out. For numerical simulation we have used Euler-Lagrange two-component approach. Using numerical simulation we have studied the growth of deposition of nanoparticles on the channel walls depending on the Reynolds number and the position of the magnet. The flow pattern, the concentration field and the trajectory of nanoparticles as a function of the Reynolds number were obtained. The good qualitative and quantitative agreement between numerical simulation and experiments was shown.

The toxic effects of l-Cysteine-capped cadmium sulfide nanoparticles on the aquatic plant Spirodela polyrrhiza

NASA Astrophysics Data System (ADS)

Khataee, Alireza; Movafeghi, Ali; Nazari, Fatemeh; Vafaei, Fatemeh; Dadpour, Mohammad Reza; Hanifehpour, Younes; Joo, Sang Woo

2014-12-01

Plants play an important role in the fate of nanoparticles in the environment through their uptake, bioaccumulation, and transfer to trophic chains. However, the impacts of nanoparticles on plants as essential components of all ecosystems are not well documented. In the present study, the toxic effects of l-Cysteine-capped CdS nanoparticles on Spirodela polyrrhiza as an aquatic higher plant species were studied. l-Cysteine-capped CdS nanoparticles were synthesized using hydrothermal method and their characteristics were determined by XRD, SEM, HR-TEM, and FT-IR techniques. The diameter of majority of synthesized nanoparticles was about 15-20 nm. Subsequently, the uptake of l-Cysteine-capped CdS nanoparticles by the plant species was confirmed using epifluorescence microscopy. The activity of peroxidase and superoxide dismutase as antioxidant enzymes was assayed and the relative frond number was calculated in the presence of different concentrations of l-Cysteine-capped CdS nanoparticles. The obtained results revealed the toxic effects of the synthesized nanoparticles on S. polyrrhiza, leading to growth reduction and significant changes in antioxidant enzymes' activity.

Use of Agave tequilana-lignin and zinc oxide nanoparticles for skin photoprotection.

PubMed

Gutiérrez-Hernández, José Manuel; Escalante, Alfredo; Murillo-Vázquez, Raquel Nalleli; Delgado, Ezequiel; González, Francisco Javier; Toríz, Guillermo

2016-10-01

The use of sunscreens is essential for preventing skin damage and the potential appearance of skin cancer in humans. Inorganic active components such as zinc oxide (ZnO) have been used commonly in sunscreens due to their ability to block UVA radiation. This ultraviolet (UV) protection might be enhanced to cover the UVB and UVC bands when combined with other components such as titanium dioxide (TiO2). In this work we evaluate the photoprotection properties of organic nanoparticles made from lignin in combination with ZnO nanoparticles as active ingredients for sunscreens. Lignin nanoparticles were synthesized from Agave tequilana lignin. Two different pulping methods were used for dissolving lignin from agave bagasse. ZnO nanoparticles were synthesized by the precipitation method. All nanoparticles were characterized by SEM, UV-Vis and FT-IR spectroscopy. Nanoparticles were mixed with a neutral vehicle in different concentrations and in-vitro sun protection factor (SPF) values were calculated. Different sizes of spherical lignin nanoparticles were obtained from the spent liquors of two different pulping methods. ZnO nanoparticles resulted with a flake shape. The mixture of all components gave SPF values in a range between 4 and 13. Lignin nanoparticles showed absorption in the UVB and UVC regions which can enhance the SPF value of sunscreens composed only of zinc oxide nanoparticles. Lignin nanoparticles have the added advantage of being of organic nature and its brown color can be used to match the skin tone of the person using it. Copyright © 2016 Elsevier B.V. All rights reserved.

Modifications in nanoparticle-protein interactions by varying the protein conformation

NASA Astrophysics Data System (ADS)

Kumar, Sugam; Yadav, I.; Aswal, V. K.; Kohlbrecher, J.

2017-05-01

Small-angle neutron scattering has been used to study the interaction of silica nanoparticle with Bovine Serum Albumin (BSA) protein without and with a protein denaturing agent urea. The measurements have been carried out at pH 7 where both the components (nanoparticle and protein) are similarly charged. We show that the interactions in nanoparticle-protein system can be modified by changing the conformation of protein through the presence of urea. In the absence of urea, the strong electrostatic repulsion between the nanoparticle and protein prevents protein adsorption on nanoparticle surface. This non-adsorption, in turn gives rise to depletion attraction between nanoparticles. However, with addition of urea the depletion attraction is completely suppressed. Urea driven denaturation of protein is utilized to expose the positively charged patched of the BSA molecules which eventually leads to adsorption of BSA on nanoparticles eliminating the depletion interaction.

Hybrid gas-to-particle conversion and chemical vapor deposition for production of high-surface area films

NASA Astrophysics Data System (ADS)

Nguyen, Quynh Tan

A hybrid process, based upon gas-to-particle conversion and chemical vapor deposition, is presented as an alternative technique for producing porous films with the main advantages of solvent-free, low-substrate temperature operation. Starting from solid precursors, nanoparticles were produced in the vapor phase. Downstream of this reaction zone, these nanoparticles were collected via thermophoresis onto a cooled substrate forming a porous film. Initially, alumina (Al2O3) films were produced. Later, multi-component processing was explored by incorporating platinum (Pt) nanoparticles into the Al2O3 matrix leading to the production of Pt/Al 2O3 films by two routes: simultaneous precursor injection processing or by a layer-by-layer approach. In single component processing, the formation of nanoparticle aggregates was evident within the amorphous Al2O3 films. Aggregates, composed of these particles, are likely held together by relatively weak van der Waals forces leading to the observed poor physical cohesion. In multi-component processing, reasonable control of composition and distribution of species is possible with Pt nanoparticles appearing to be co-agglomerated with alumina. Deposited crystalline Pt nanoparticles may encourage the crystallization of the amorphous Al2O3. Finally, from chemisorption results, the produced sample appears to have potentially greater catalytic activity than a commercially available standard. A model is in development to study nanoparticle interactions with a gas and deposition occurring in stagnation flow onto the cooled horizontal substrate within the tubular reactor. Using velocity and temperature fields generated from numerical solutions to the Navier-Stokes and energy equations, particle trajectories were calculated from the summation of drag, gravitational, thermophoretic, and Brownian forces. In rectangular coordinates, cooling stage width to reactor diameter ratio, deposition stage temperature, and initial velocity were the primary parameters varied in this study. An optimum balance between thermophoretic and drag forces appears to be the key factor in obtaining high yield and surface uniformity in the films. The results also suggest that Brownian motion is not a significant contributor to deposition under conditions in this study.

Modifications in structure and interaction of nanoparticle-protein-surfactant complexes in electrolyte solution

NASA Astrophysics Data System (ADS)

Mehan, Sumit; Kumar, S.; Aswal, V. K.; Schweins, R.

2016-05-01

SANS experiments of three-component system of anionic silica nanoparticles, anionic BSA protein and anionic SDS surfactants have been carried out without and with electrolyte in aqueous solution. In both the cases, the interaction of surfactant with protein results in formation of bead-necklace structure of protein-surfactant complexes in solution. These protein-surfactant complexes interact very differently with nanoparticles in absence and presence of electrolyte. In absence of electrolyte, nanoparticles remain in dispersed phase in solution, whereas with the addition of electrolyte the nanoparticles fractal aggregates are formed. SANS describes the phase behavior to be governed by competition of electrostatic and depletion interactions among the components solution.

Protamine-based nanoparticles as new antigen delivery systems.

PubMed

González-Aramundiz, José Vicente; Peleteiro Olmedo, Mercedes; González-Fernández, África; Alonso Fernández, María José; Csaba, Noemi Stefánia

2015-11-01

The use of biodegradable nanoparticles as antigen delivery vehicles is an attractive approach to overcome the problems associated with the use of Alum-based classical adjuvants. Herein we report, the design and development of protamine-based nanoparticles as novel antigen delivery systems, using recombinant hepatitis B surface antigen as a model viral antigen. The nanoparticles, composed of protamine and a polysaccharide (hyaluronic acid or alginate), were obtained using a mild ionic cross-linking technique. The size and surface charge of the nanoparticles could be modulated by adjusting the ratio of the components. Prototypes with optimal physicochemical characteristics and satisfactory colloidal stability were selected for the assessment of their antigen loading capacity, antigen stability during storage and in vitro and in vivo proof-of-concept studies. In vitro studies showed that antigen-loaded nanoparticles induced the secretion of cytokines by macrophages more efficiently than the antigen in solution, thus indicating a potential adjuvant effect of the nanoparticles. Finally, in vivo studies showed the capacity of these systems to trigger efficient immune responses against the hepatitis B antigen following intramuscular administration, suggesting the potential interest of protamine-polysaccharide nanoparticles as antigen delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Absorption properties of metal-semiconductor hybrid nanoparticles.

PubMed

Shaviv, Ehud; Schubert, Olaf; Alves-Santos, Marcelo; Goldoni, Guido; Di Felice, Rosa; Vallée, Fabrice; Del Fatti, Natalia; Banin, Uri; Sönnichsen, Carsten

2011-06-28

The optical response of hybrid metal-semiconductor nanoparticles exhibits different behaviors due to the proximity between the disparate materials. For some hybrid systems, such as CdS-Au matchstick-shaped hybrids, the particles essentially retain the optical properties of their original components, with minor changes. Other systems, such as CdSe-Au dumbbell-shaped nanoparticles, exhibit significant change in the optical properties due to strong coupling between the two materials. Here, we study the absorption of these hybrids by comparing experimental results with simulations using the discrete dipole approximation method (DDA) employing dielectric functions of the bare components as inputs. For CdS-Au nanoparticles, the DDA simulation provides insights on the gold tip shape and its interface with the semiconductor, information that is difficult to acquire by experimental means alone. Furthermore, the qualitative agreement between DDA simulations and experimental data for CdS-Au implies that most effects influencing the absorption of this hybrid system are well described by local dielectric functions obtained separately for bare gold and CdS nanoparticles. For dumbbell shaped CdSe-Au, we find a shortcoming of the electrodynamic model, as it does not predict the "washing out" of the optical features of the semiconductor and the metal observed experimentally. The difference between experiment and theory is ascribed to strong interaction of the metal and semiconductor excitations, which spectrally overlap in the CdSe case. The present study exemplifies the employment of theoretical approaches used to describe the optical properties of semiconductors and metal nanoparticles, to achieve better understanding of the behavior of metal-semiconductor hybrid nanoparticles.

Interaction of engineered nanoparticles with various components of the environment and possible strategies for their risk assessment.

PubMed

Bhatt, Indu; Tripathi, Bhumi Nath

2011-01-01

Nanoparticles are the materials with at least two dimensions between 1 and 100 nm. Mostly these nanoparticles are natural products but their tremendous commercial use has boosted the artificial synthesis of these particles (engineered nanoparticles). Accelerated production and use of these engineered nanoparticles may cause their release in the environment and facilitate the frequent interactions with biotic and abiotic components of the ecosystems. Despite remarkable commercial benefits, their presence in the nature may cause hazardous biological effects. Therefore, detail understanding of their sources, release interaction with environment, and possible risk assessment would provide a basis for safer use of engineered nanoparticles with minimal or no hazardous impact on environment. Keeping all these points in mind the present review provides updated information on various aspects, e.g. sources, different types, synthesis, interaction with environment, possible strategies for risk management of engineered nanoparticles. Copyright © 2010 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 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

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

Nanoparticles affect PCR primarily via surface interactions with PCR components: using amino-modified silica-coated magnetic nanoparticles as a main model

USDA-ARS?s Scientific Manuscript database

Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic n...

Micelle depletion-induced vs. micelle-mediated aggregation in nanoparticles

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

Ray, D., E-mail: debes.phys@gmail.com; Aswal, V. K.

2015-06-24

The phase behavior anionic silica nanoparticle (Ludox LS30) with non-ionic surfactants decaethylene glycol monododecylether (C12E10) and cationic dodecyltrimethyl ammonium bromide (DTAB) in aqueous electrolyte solution has been studied by small-angle neutron scattering (SANS). The measurements have been carried out for fixed concentrations of nanoparticle (1 wt%), surfactants (1 wt%) and electrolyte (0.1 M NaCl). Each of these nanoparticle–surfactant systems has been examined for different contrast conditions where individual components (nanoparticle or surfactant) are made visible. It is observed that the nanoparticle-micelle system in both the cases lead to the aggregation of nanoparticles. The aggregation is found to be micelle depletion-inducedmore » for C12E10 whereas micelle-mediated aggregation for DTAB. Interestingly, it is also found that phase behavior of mixed surfactant (C12E10 + DTAB) system is similar to that of C12E10 (unlike DTAB) micelles with nanoparticles.« less

Study the structural and optical behaviour of polyaniline/ZrO2 nanocomposites

NASA Astrophysics Data System (ADS)

Sidhu, Gaganpreet Kaur; Kumar, Naresh; Kumar, Rajesh

2018-05-01

In nanoscience, hybrid material based on polymer and nanoparticles are of great interest because of much improved properties of components. Polymers are of enormous interest because of their various properties like flexibility, low weight and easy processing. Here, we studied the influence of ZrO2 nanoparticles on the structural and optical properties of Polyaniline (PANI). ZrO2 mixed with PANI, improve its structural and optical properties. XRD studies reveal that ZrO2 nanoparticles exist in the tetragonal phase in ZrO2/PANI nanocomposites. UV-Vis spectroscopic studies have been carried out to understand the presence of various energy levels and their involvement in absorbance of light. In PANI nanocomposites, aniline monomer attach with ZrO2 nanoparticles through p-p stacking interaction, Vander waal force and hydrogen bonding interaction.

Cryo-STEM-EDX spectroscopy for the characterisation of nanoparticles in cell culture media

NASA Astrophysics Data System (ADS)

Ilett, M.; Bamiduro, F.; Matar, O.; Brown, A.; Brydson, R.; Hondow, N.

2017-09-01

We present a study of barium titanate nanoparticles dispersed in cell culture media. Scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy was undertaken on samples prepared using both conventional drop casting and also plunge freezing and examination under cryogenic conditions. This showed that drying artefacts occurred during conventional sample preparation, whereby some salt components of the cell culture media accumulated around the barium titanate nanoparticles; these were removed using the cryogenic route. Importantly, the formation of a calcium and phosphorus rich coating around the barium titanate nanoparticles was retained under cryo-conditions, highlighting that significant interactions do occur between nanomaterials and biological media.

Bio-synthesis of silver nanoparticles using Potentilla fulgens Wall. ex Hook. and its therapeutic evaluation as anticancer and antimicrobial agent.

PubMed

Mittal, Amit Kumar; Tripathy, Debabrata; Choudhary, Alka; Aili, Pavan Kumar; Chatterjee, Anupam; Singh, Inder Pal; Banerjee, Uttam Chand

2015-08-01

The present study aims to develop an easy and eco-friendly method for the synthesis of silver nanoparticles using extracts from the medicinal plant, Potentilla fulgens and evaluation of its anticancer and antimicrobial properties. The various parts of P. fulgens were screened and the root extract was found to have the highest potential for the synthesis of nanoparticles. The root extracts were able to quickly reduce Ag(+) to Ag(0) and stabilized the nanoparticles. The synthesis of nanoparticles was confirmed by UV-Visible spectrophotometry and further characterized using Zeta sizer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Electron microscopic study showed that the size of the nanoparticle was in the range of 10 to 15 nm and spherical in shape. The studies of phytochemical analysis of nanoparticles indicated that the adsorbed components on the surface of nanoparticles were mainly flavonoid in nature. Furthermore, nanoparticles were evaluated as cytotoxic against various cancer cell lines and 0.2 to 12 μg/mL nanoparticles showed good toxicity. The IC50 value of nanoparticles was found to be 4.91 and 8.23 μg/mL against MCF-7 and U-87 cell lines, respectively. Additionally, the apoptotic effect of synthesized nanoparticles on normal and cancer cells was studied using trypan blue assay and flow-cytometric analysis. The results indicate the synthesized nanoparticle ability to kill cancer cells compared to normal cells. The nanoparticles also exhibited comparable antimicrobial activity against both Gram-positive and Gram-negative bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthetic Strategies in the Preparation of Polymer/Inorganic Hybrid Nanoparticles

PubMed Central

Hood, Matthew A.; Mari, Margherita; Muñoz-Espí, Rafael

2014-01-01

This article reviews the recent advances and challenges in the preparation of polymer/inorganic hybrid nanoparticles. We mainly focus on synthetic strategies, basing our classification on whether the inorganic and the polymer components have been formed in situ or ex situ, of the hybrid material. Accordingly, four types of strategies are identified and described, referring to recent examples: (i) ex situ formation of the components and subsequent attachment or integration, either by covalent or noncovalent bonding; (ii) in situ polymerization in the presence of ex situ formed inorganic nanoparticles; (iii) in situ precipitation of the inorganic components on or in polymer structures; and (iv) strategies in which both polymer and inorganic component are simultaneously formed in situ. PMID:28788665

DNA-controlled assembly of a NaTl lattice structure from gold nanoparticles and protein nanoparticles

NASA Astrophysics Data System (ADS)

Cigler, Petr; Lytton-Jean, Abigail K. R.; Anderson, Daniel G.; Finn, M. G.; Park, Sung Yong

2010-11-01

The formation of diamond structures from tailorable building blocks is an important goal in colloidal crystallization because the non-compact diamond lattice is an essential component of photonic crystals for the visible-light range. However, designing nanoparticle systems that self-assemble into non-compact structures has proved difficult. Although several methods have been proposed, single-component nanoparticle assembly of a diamond structure has not been reported. Binary systems, in which at least one component is arranged in a diamond lattice, provide alternatives, but control of interparticle interactions is critical to this approach. DNA has been used for this purpose in a number of systems. Here we show the creation of a non-compact lattice by DNA-programmed crystallization using surface-modified Qβ phage capsid particles and gold nanoparticles, engineered to have similar effective radii. When combined with the proper connecting oligonucleotides, these components form NaTl-type colloidal crystalline structures containing interpenetrating organic and inorganic diamond lattices, as determined by small-angle X-ray scattering. DNA control of assembly is therefore shown to be compatible with particles possessing very different properties, as long as they are amenable to surface modification.

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.

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.

Synchronous microencapsulation of multiple components in silymarin into PLGA nanoparticles by an emulsification/solvent evaporation method.

PubMed

Xie, Yunchang; Yi, Yueneng; Hu, Xiongwei; Shangguan, Mingzhu; Wang, Lijuan; Lu, Yi; Qi, Jianping; Wu, Wei

2016-09-01

The development of polymeric carriers loaded with extracts suffers from the drawback not to be able to incorporate simultaneously various pharmacological compounds into the formulation. The aim of this study was therefore to achieve synchronous microencapsulation of multiple components of silymarin into poly (lactic-co-glycolic acid) nanoparticle, the most commonly used polymeric carrier with biodegradability and safety. The main strategy taken was to improve the overall entrapment efficiency and to reduce the escaping ratio of the components of different physicochemical properties. The optimized nanoparticles were spherical in morphology with a mean particle size of 150 ± 5 nm. Under common preparative conditions, silybin and isosilybin were entrapped in high efficiency, whereas taxifolin, silychristin and silydianin, especially taxifolin, showed less entrapment because they were more hydrophilic. By changing the pH of the outer aqueous phase and saturating it with silymarin, the entrapment efficiency of taxifolin, silychristin and silydianin could be significantly improved to over 90%, the level similar to silybin and isosilybin, thereby achieving synchronous encapsulation. It could be concluded that synchronous encapsulation of multiple components of silymarin was achieved by optimizing the preparative variables.

Nanoparticle-blood interactions: the implications on solid tumour targeting.

PubMed

Lazarovits, James; Chen, Yih Yang; Sykes, Edward A; Chan, Warren C W

2015-02-18

Nanoparticles are suitable platforms for cancer targeting and diagnostic applications. Typically, less than 10% of all systemically administered nanoparticles accumulate in the tumour. Here we explore the interactions of blood components with nanoparticles and describe how these interactions influence solid tumour targeting. In the blood, serum proteins adsorb onto nanoparticles to form a protein corona in a manner dependent on nanoparticle physicochemical properties. These serum proteins can block nanoparticle tumour targeting ligands from binding to tumour cell receptors. Additionally, serum proteins can also encourage nanoparticle uptake by macrophages, which decreases nanoparticle availability in the blood and limits tumour accumulation. The formation of this protein corona will also increase the nanoparticle hydrodynamic size or induce aggregation, which makes nanoparticles too large to enter into the tumour through pores of the leaky vessels, and prevents their deep penetration into tumours for cell targeting. Recent studies have focused on developing new chemical strategies to reduce or eliminate serum protein adsorption, and rescue the targeting potential of nanoparticles to tumour cells. An in-depth and complete understanding of nanoparticle-blood interactions is key to designing nanoparticles with optimal physicochemical properties with high tumour accumulation. The purpose of this review article is to describe how the protein corona alters the targeting of nanoparticles to solid tumours and explains current solutions to solve this problem.

Generation of Well-Defined Micro/Nanoparticles via Advanced Manufacturing Techniques for Therapeutic Delivery

PubMed Central

Zhang, Peipei; Xia, Junfei; Luo, Sida

2018-01-01

Micro/nanoparticles have great potentials in biomedical applications, especially for drug delivery. Existing studies identified that major micro/nanoparticle features including size, shape, surface property and component materials play vital roles in their in vitro and in vivo applications. However, a demanding challenge is that most conventional particle synthesis techniques such as emulsion can only generate micro/nanoparticles with a very limited number of shapes (i.e., spherical or rod shapes) and have very loose control in terms of particle sizes. We reviewed the advanced manufacturing techniques for producing micro/nanoparticles with precisely defined characteristics, emphasizing the use of these well-controlled micro/nanoparticles for drug delivery applications. Additionally, to illustrate the vital roles of particle features in therapeutic delivery, we also discussed how the above-mentioned micro/nanoparticle features impact in vitro and in vivo applications. Through this review, we highlighted the unique opportunities in generating controllable particles via advanced manufacturing techniques and the great potential of using these micro/nanoparticles for therapeutic delivery. PMID:29670013

Nanoparticles in Medicine: Selected Observations and Experimental Caveats.

PubMed

Thomsen, Sharon; Pearce, John A; Giustini, Andrew; Hoopes, P Jack

2013-02-26

Medically useful nanoparticles measure 1-100 nm in at least one dimension and are engineered and manufactured for specific diagnostic and treatment applications. Most nanoparticles used currently used in medicine are engineered and manufactured for specific purposes. Medically significant nanoparticles are composed of a 1) central core that is usually the medically active component, 2) one or more layers of organic or inorganic materials that forms a capsule (corona) covering the core and 3) an outer surface layer that interacts with the environment and/or targeted cells and tissues. Effective nanoparticle function in the living, intact animal or human requires electrochemical stability necessary to bypass the reticuloendothelial system (RES) and avoid filtration through the renal glomerulus into the urine. Nanoparticles are present in "natural" as well as the manufacturing and clinical environments thus could pose as significant toxins because of their small sizes, their chemical and drug content and potential effect of causing long term disease including allergies, chronic inflammation and cancer. Currently published studies have focused on the effects of nanoparticles on cells in the extremely artificial environments of cell cultures. More clinical and preclinical studies documenting the short term and long term effects nanoparticle in the intact experimental animal and human are needed.

Nanoparticles in medicine: selected observations and experimental caveats

NASA Astrophysics Data System (ADS)

Thomsen, Sharon; Pearce, John A.; Giustini, Andrew; Hoopes, P. Jack

2013-02-01

Medically useful nanoparticles measure 1-100 nm in at least one dimension and are engineered and manufactured for specific diagnostic and treatment applications. Most nanoparticles used currently used in medicine are engineered and manufactured for specific purposes. Medically significant nanoparticles are composed of a 1) central core that is usually the medically active component, 2) one or more layers of organic or inorganic materials that forms a capsule (corona) covering the core and 3) an outer surface layer that interacts with the environment and/or targeted cells and tissues. Effective nanoparticle function in the living, intact animal or human requires electrochemical stability necessary to bypass the reticuloendothelial system (RES) and avoid filtration through the renal glomerulus into the urine. Nanoparticles are present in " natural" as well as the manufacturing and clinical environments thus could pose as significant toxins because of their small sizes, their chemical and drug content and potential effect of causing long term disease including allergies, chronic inflammation and cancer. Currently published studies have focused on the effects of nanoparticles on cells in the extremely artificial environments of cell cultures. More clinical and preclinical studies documenting the short term and long term effects nanoparticle in the intact experimental animal and human are needed.

Biokinetics of food additive silica nanoparticles and their interactions with food components.

PubMed

Lee, Jeong-A; Kim, Mi-Kyung; Song, Jae Ho; Jo, Mi-Rae; Yu, Jin; Kim, Kyoung-Min; Kim, Young-Rok; Oh, Jae-Min; Choi, Soo-Jin

2017-02-01

Nanomaterials have been widely utilized in the food industry in production, packaging, sensors, nutrient delivery systems, and food additives. However, research on the interactions between food-grade nanoparticles and biomolecules as well as their potential toxicity is limited. In the present study, the in vivo solubility, oral absorption, tissue distribution, and excretion kinetics of one of the most extensively used food additives, silica (SiO 2 ) were evaluated with respect to particle size (nano vs bulk) following single-dose oral administration to rats. Intestinal transport mechanism was investigated using a 3D culture system, in vitro model of human intestinal follicle-associated epithelium (FAE). The effect of the presence of food components, such as sugar and protein, on the oral absorption of nanoparticles was also evaluated with focus on their interactions. The results obtained demonstrated that the oral absorption of nanoparticles (3.94±0.38%) was greater than that of bulk materials (2.95±0.37%), possibly due to intestinal transport by microfold (M) cells. On the other hand, particle size was found to have no significant effect on in vivo dissolution property, biodistribution, or excretion kinetics. Oral absorption profile of silica nanoparticles was highly dependent on the presence of sugar or protein, showing rapid absorption rate in glucose, presumably due to their surface interaction on nanoparticles. These findings will be useful for predicting the potential toxicity of food-grade nanoparticles and for understanding biological interactions. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced Delivery of Chemotherapy to Tumors Using a Multi-Component Nanochain with Radiofrequency-Tunable Drug Release

PubMed Central

Peiris, Pubudu M.; Bauer, Lisa; Toy, Randall; Tran, Emily; Pansky, Jenna; Doolittle, Elizabeth; Schmidt, Erik; Hayden, Elliott; Mayer, Aaron; Keri, Ruth A.; Griswold, Mark A.; Karathanasis, Efstathios

2012-01-01

While nanoparticles maximize the amount of chemotherapeutic drug in tumors relative to normal tissues, nanoparticle-based drugs are not accessible to the majority of cancer cells because nanoparticles display patchy, near-perivascular accumulation in tumors. To overcome the limitations of current drugs in their molecular or nanoparticle form, we developed a nanoparticle based on multi-component nanochains to deliver drug to the majority of cancer cells throughout a tumor while reducing off-target delivery. The nanoparticle is composed of three magnetic nanospheres and one doxorubicin-loaded liposome assembled in a 100-nm-long chain. These nanoparticles display prolonged blood circulation and significant intratumoral deposition in tumor models in rodents. Furthermore, the magnetic particles of the chains serve as a mechanical transducer to transfer radiofrequency energy to the drug-loaded liposome. The defects on the liposomal walls trigger the release of free drug capable of spreading throughout the entire tumor, which results in a wide-spread anticancer effect. PMID:22486623

D-Optimal mixture experimental design for stealth biodegradable crosslinked docetaxel-loaded poly-ε-caprolactone nanoparticles manufactured by dispersion polymerization.

PubMed

Ogunwuyi, O; Adesina, S; Akala, E O

2015-03-01

We report here our efforts on the development of stealth biodegradable crosslinked poly-ε-caprolactone nanoparticles by free radical dispersion polymerization suitable for the delivery of bioactive agents. The uniqueness of the dispersion polymerization technique is that it is surfactant free, thereby obviating the problems known to be associated with the use of surfactants in the fabrication of nanoparticles for biomedical applications. Aided by a statistical software for experimental design and analysis, we used D-optimal mixture statistical experimental design to generate thirty batches of nanoparticles prepared by varying the proportion of the components (poly-ε-caprolactone macromonomer, crosslinker, initiators and stabilizer) in acetone/water system. Morphology of the nanoparticles was examined using scanning electron microscopy (SEM). Particle size and zeta potential were measured by dynamic light scattering (DLS). Scheffe polynomial models were generated to predict particle size (nm) and particle surface zeta potential (mV) as functions of the proportion of the components. Solutions were returned from simultaneous optimization of the response variables for component combinations to (a) minimize nanoparticle size (small nanoparticles are internalized into disease organs easily, avoid reticuloendothelial clearance and lung filtration) and (b) maximization of the negative zeta potential values, as it is known that, following injection into the blood stream, nanoparticles with a positive zeta potential pose a threat of causing transient embolism and rapid clearance compared to negatively charged particles. In vitro availability isotherms show that the nanoparticles sustained the release of docetaxel for 72 to 120 hours depending on the formulation. The data show that nanotechnology platforms for controlled delivery of bioactive agents can be developed based on the nanoparticles.

The nanoparticle protein corona formed in human blood or human blood fractions.

PubMed

Lundqvist, Martin; Augustsson, Cecilia; Lilja, Malin; Lundkvist, Kristoffer; Dahlbäck, Björn; Linse, Sara; Cedervall, Tommy

2017-01-01

The protein corona formed around nanoparticles in protein-rich fluids plays an important role for nanoparticle biocompatibility, as found in several studies during the last decade. Biological fluids have complex compositions and the molecular components interact and function together in intricate networks. Therefore, the process to isolate blood or the preparation of blood derivatives may lead to differences in the composition of the identified protein corona around nanoparticles. Here, we show distinct differences in the protein corona formed in whole blood, whole blood with EDTA, plasma, or serum. Furthermore, the ratio between particle surface area to protein concentration influences the detected corona. We also show that the nanoparticle size per se influences the formed protein corona due to curvature effects. These results emphasize the need of investigating the formation and biological importance of the protein corona in the same environment as the nanoparticles are intended for or released into.

Evaluation of the antibacterial activity of a conventional orthodontic composite containing silver/hydroxyapatite nanoparticles.

PubMed

Sodagar, Ahmad; Akhavan, Azam; Hashemi, Ehsan; Arab, Sepideh; Pourhajibagher, Maryam; Sodagar, Kosar; Kharrazifard, Mohammad Javad; Bahador, Abbas

2016-12-01

One of the most important complications of fixed orthodontic treatment is the formation of white spots which are initial carious lesions. Addition of antimicrobial agents into orthodontic adhesives might be a wise solution for prevention of white spot formation. The aim of this study was to evaluate the antibacterial properties of a conventional orthodontic adhesive containing three different concentrations of silver/hydroxyapatite nanoparticles. One hundred and sixty-two Transbond XT composite discs containing 0, 1, 5, and 10 % silver/hydroxyapatite nanoparticles were prepared and sterilized. Antibacterial properties of these composite groups against Streptococcus mutans, Lactobacillus acidophilus, and Streptococcus sanguinis were investigated using three different antimicrobial tests. Disk agar diffusion test was performed to assess the diffusion of antibacterial agent on brain heart infusion agar plate by measuring bacterial growth inhibition zones. Biofilm inhibition test showed the antibacterial capacity of composite discs against resistant bacterial biofilms. Antimicrobial activity of eluted components from composite discs was investigated by comparing the viable counts of bacteria after 3, 15, and 30 days. Composite discs containing 5 and 10 % silver/hydroxyapatite nanoparticles were capable of producing growth inhibition zones for all bacterial types. Results of biofilm inhibition test showed that all of the study groups reduced viable bacterial count in comparison to the control group. Antimicrobial activity of eluted components from composite discs was immensely diverse based on the bacterial type and the concentration of nanoparticles. Transbond XT composite discs containing 5 and 10 % silver/hydroxyapatite nanoparticles produce bacterial growth inhibition zones and show antibacterial properties against biofilms.

Transmission electron microscopy of unstained hybrid Au nanoparticles capped with PPAA (plasma-poly-allylamine): structure and electron irradiation effects.

PubMed

Gontard, Lionel C; Fernández, Asunción; Dunin-Borkowski, Rafal E; Kasama, Takeshi; Lozano-Pérez, Sergio; Lucas, Stéphane

2014-12-01

Hybrid (organic shell-inorganic core) nanoparticles have important applications in nanomedicine. Although the inorganic components of hybrid nanoparticles can be characterized readily using conventional transmission electron microscopy (TEM) techniques, the structural and chemical arrangement of the organic molecular components remains largely unknown. Here, we apply TEM to the physico-chemical characterization of Au nanoparticles that are coated with plasma-polymerized-allylamine, an organic compound with the formula C3H5NH2. We discuss the use of energy-filtered TEM in the low-energy-loss range as a contrast enhancement mechanism for imaging the organic shells of such particles. We also study electron-beam-induced crystallization and amorphization of the shells and the formation of graphitic-like layers that contain both C and N. The resistance of the samples to irradiation by high-energy electrons, which is relevant for optical tuning and for understanding the degree to which such hybrid nanostructures are stable in the presence of biomedical radiation, is also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Functionalized nanoparticle probes for protein detection

NASA Astrophysics Data System (ADS)

Park, Do Hyun; Lee, Jae-Seung

2015-05-01

In this Review, we discuss representative studies of recent advances in the development of nanoparticle-based protein detection methods, with a focus on the properties and functionalization of nanoparticle probes, as well as their use in detection schemes. We have focused on functionalized nanoparticle probes because they offer a number of advantages over conventional assays and because their use for detecting protein targets for diagnostic purposed has been demonstrated. In this report, we discuss nanoparticle probes classified by material type (gold, silver, silica, semiconductor, carbon, and virus) and surface functionality (antibody, aptamer, and DNA), which play a critical role in enhancing the sensitivity, selectivity, and efficiency of the detection systems. In particular, the synergistic function of each component of the nanoparticle probe is emphasized in terms of specific chemical and physical properties. This research area is in its early stages with many milestones to reach before nanoparticle probes are successfully applied in the field; however, the substantial ongoing efforts of researchers underline the great promise offered by nanoparticlebased probes for future applications. [Figure not available: see fulltext.

HDL-mimetic PLGA nanoparticle to target atherosclerosis plaque macrophages.

PubMed

Sanchez-Gaytan, Brenda L; Fay, Francois; Lobatto, Mark E; Tang, Jun; Ouimet, Mireille; Kim, YongTae; van der Staay, Susanne E M; van Rijs, Sarian M; Priem, Bram; Zhang, Liangfang; Fisher, Edward A; Moore, Kathryn J; Langer, Robert; Fayad, Zahi A; Mulder, Willem J M

2015-03-18

High-density lipoprotein (HDL) is a natural nanoparticle that exhibits an intrinsic affinity for atherosclerotic plaque macrophages. Its natural targeting capability as well as the option to incorporate lipophilic payloads, e.g., imaging or therapeutic components, in both the hydrophobic core and the phospholipid corona make the HDL platform an attractive nanocarrier. To realize controlled release properties, we developed a hybrid polymer/HDL nanoparticle composed of a lipid/apolipoprotein coating that encapsulates a poly(lactic-co-glycolic acid) (PLGA) core. This novel HDL-like nanoparticle (PLGA-HDL) displayed natural HDL characteristics, including preferential uptake by macrophages and a good cholesterol efflux capacity, combined with a typical PLGA nanoparticle slow release profile. In vivo studies carried out with an ApoE knockout mouse model of atherosclerosis showed clear accumulation of PLGA-HDL nanoparticles in atherosclerotic plaques, which colocalized with plaque macrophages. This biomimetic platform integrates the targeting capacity of HDL biomimetic nanoparticles with the characteristic versatility of PLGA-based nanocarriers.

HDL-Mimetic PLGA Nanoparticle To Target Atherosclerosis Plaque Macrophages

PubMed Central

Sanchez-Gaytan, Brenda L.; Fay, Francois; Lobatto, Mark E.; Tang, Jun; Ouimet, Mireille; Kim, YongTae; van der Staay, Susanne E. M.; van Rijs, Sarian M.; Priem, Bram; Zhang, Liangfang; Fisher, Edward A; Moore, Kathryn J.; Langer, Robert; Fayad, Zahi A.; Mulder, Willem J M

2015-01-01

High-density lipoprotein (HDL) is a natural nanoparticle that exhibits an intrinsic affinity for atherosclerotic plaque macrophages. Its natural targeting capability as well as the option to incorporate lipophilic payloads, e.g., imaging or therapeutic components, in both the hydrophobic core and the phospholipid corona make the HDL platform an attractive nanocarrier. To realize controlled release properties, we developed a hybrid polymer/HDL nanoparticle composed of a lipid/apolipoprotein coating that encapsulates a poly(lactic-co-glycolic acid) (PLGA) core. This novel HDL-like nanoparticle (PLGA–HDL) displayed natural HDL characteristics, including preferential uptake by macrophages and a good cholesterol efflux capacity, combined with a typical PLGA nanoparticle slow release profile. In vivo studies carried out with an ApoE knockout mouse model of atherosclerosis showed clear accumulation of PLGA–HDL nanoparticles in atherosclerotic plaques, which colocalized with plaque macrophages. This biomimetic platform integrates the targeting capacity of HDL biomimetic nanoparticles with the characteristic versatility of PLGA-based nanocarriers. PMID:25650634

Floral Biosynthesis of Mn3O4 and Fe2O3 Nanoparticles Using Chaenomeles sp. Flower Extracts for Efficient Medicinal Applications

NASA Astrophysics Data System (ADS)

Karunakaran, Gopalu; Jagathambal, Matheswaran; Kolesnikov, Evgeny; Dmitry, Arkhipov; Ishteev, Artur; Gusev, Alexander; Kuznetsov, Denis

2017-08-01

Manganese oxide (Mn3O4) and iron oxide (Fe2O3) nanoparticles were successfully synthesized with the flower extracts of Chaenomeles sp. This is the first ever approach to synthesize nanoparticles from Chaenomeles sp. flower extracts. The organic molecules present in the flower extracts actively converted the nitrate precursor into its corresponding nanoparticles. The organic molecules that are involved in the synthesis of nanoparticles are identified using different phytochemical and gas chromatography-mass spectrometry analyses. The identified components are glycosides, alkaloids, terpenoids, saponins, flavonoids, quinines, and steroids. The structural and chemical compositions of the synthesized powder were also analyzed. The x-ray powder diffraction analysis revealed that the particles show tetragonal and rhombohedral crystalline phases. The Fourier transform infrared spectroscopy analysis showed the functional groups that are involved in the reduction of nitrates into the corresponding nanoparticles. Energy-dispersive x-ray spectroscopy analysis confirmed the presence of the elements in the synthesized nanoparticles. Transmission electron microscopy images showed the formation of spherical nanoparticles with an average size of 30-100 nm. Antioxidant analysis showed that the synthesized nanoparticles had excellent antioxidant potential. The antibacterial study showed that they inhibit the growth of harmful bacteria such as Pseudomonas aeruginosa and Streptococcus pyogenes. Thus, this study proposes a new eco-friendly and nontoxic method to synthesize nanoparticles for medicinal applications.

Biogenic synthesis of silver nanoparticles by leaf extract of Cassia angustifolia

NASA Astrophysics Data System (ADS)

Amaladhas, T. Peter; Sivagami, S.; Akkini Devi, T.; Ananthi, N.; Priya Velammal, S.

2012-12-01

In this study Cassia angustifolia (senna) is used for the environmentally friendly synthesis of silver nanoparticles. Stable silver nanoparticles having symmetric surface plasmon resonance (SPR) band centred at 420 nm were obtained within 10 min at room temperature by treating aqueous solutions of silver nitrate with C. angustifolia leaf extract. The water soluble components from the leaves, probably the sennosides, served as both reducing and capping agents in the synthesis of silver nanoparticles. The nanoparticles were characterized using UV-Vis, Fourier transform infrared (FTIR) spectroscopic techniques and transmission electron microscopy (TEM). The nanoparticles were poly-dispersed, spherical in shape with particle size in the range 9-31 nm, the average size was found to be 21.6 nm at pH 11. The zeta potential was -36.4 mV and the particles were stable for 6 months. The crystalline phase of the nanoparticles was confirmed from the selected area diffraction pattern (SAED). The rate of formation and size of silver nanoparticles were pH dependent. Functional groups responsible for capping of silver nanoparticles were identified from the FTIR spectrum. The synthesized silver nanoparticles exhibited good antibacterial potential against Escherichia coli and Staphylococcus aureus.

Edible lipid nanoparticles: digestion, absorption, and potential toxicity.

PubMed

McClements, David Julian

2013-10-01

Food-grade nanoemulsions are being increasingly used in the food and beverage industry to encapsulate, protect, and deliver hydrophobic functional components, such as oil-soluble flavors, colors, preservatives, vitamins, and nutraceuticals. These nanoemulsions contain lipid nanoparticles (radius <100 nm) whose physicochemical characteristics (e.g., composition, dimensions, structure, charge, and physical state) can be controlled by selection of appropriate ingredients and fabrication techniques. Nanoemulsions have a number of potential advantages over conventional emulsions for applications within the food industry: higher stability to particle aggregation and gravitational separation; higher optical transparency; and, increased bioavailability of encapsulated components. On the other hand, there are also some risks associated with consumption of lipid nanoparticles that should be considered before they are widely utilized, such as their ability to alter the fate of bioactive components within the gastrointestinal tract and the potential toxicity of some of the components used in their fabrication (e.g., surfactants and organic solvents). This article provides an overview of the current status of the biological fate and potential toxicity of food-grade lipid nanoparticles suitable for utilization within the food and beverage industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Stabilizers influence drug–polymer interactions and physicochemical properties of disulfiram-loaded poly-lactide-co-glycolide nanoparticles

PubMed Central

Hoda, Muddasarul; Sufi, Shamim Akhtar; Cavuturu, Bindumadhuri; Rajagopalan, Rukkumani

2018-01-01

Aim: Stabilizers are known to be an integral component of polymeric nanostructures. Ideally, they manipulate physicochemical properties of nanoparticles. Based on this hypothesis, we demonstrated that disulfiram (drug) and Poly-lactide-co-glycolide (polymer) interactions and physicochemical properties of their nanoparticles formulations are significantly influenced by the choice of stabilizers. Methodology: Electron microscopy, differential scanning calorimetry, x-ray diffraction, Raman spectrum analysis, isothermal titration calorimetry and in silico docking studies were performed. Results & discussion: Polysorbate 80 imparted highest crystallinity while Triton-X 100 imparted highest rigidity, possibly influencing drug bioavailability, blood-retention time, cellular uptake and sustained drug release. All the molecular interactions were hydrophobic in nature and entropy driven. Therefore, polymeric nanoparticles may be critically manipulated to streamline the passive targeting of drug-loaded nanoparticles. PMID:29379637

Curcumin conjugated silica nanoparticles for improving bioavailability and its anticancer applications.

PubMed

Gangwar, Rajesh K; Tomar, Geetanjali B; Dhumale, Vinayak A; Zinjarde, Smita; Sharma, Rishi B; Datar, Suwarna

2013-10-09

Curcumin, a yellow bioactive component of Indian spice turmeric, is known to have a wide spectrum of biological applications. In spite of various astounding therapeutic properties, it lacks in bioavailability mainly due to its poor solubility in water. In this work, we have conjugated curcumin with silica nanoparticles to improve its aqueous solubility and hence to make it more bioavailable. Conjugation and loading of curcumin with silica nanoparticles was further examined with transmission electron microscope (TEM) and thermogravimetric analyzer. Cytotoxicity analysis of synthesized silica:curcumin conjugate was studied against HeLa cell lines as well as normal fibroblast cell lines. This study shows that silica:curcumin conjugate has great potential for anticancer application.

Simulation study of depositing the carbon film on nanoparticles in the magnetized methane plasma

NASA Astrophysics Data System (ADS)

Mohammadzadeh, Hosein; Pourali, Nima; Ebadi, Zahra

2018-03-01

Plasma coating of nanoparticles in low-temperature magnetized methane plasma is studied by a simulation approach. To this end, by using the global model, the electron temperature and concentration of different species considered in this plasma are determined in the center of a capacitively coupled discharge. Then, the plasma-wall transition region in the presence of an oblique magnetic field is simulated by the multi-component fluid description. Nanoparticles with different radii are injected into the transition region and surface deposition and heating models, as well as dynamics and charging models, are employed to examine the coating process. The results of the simulation show that the non-spherical growth of nanoparticles is affected by the presence of the magnetic field, as with passing time, an oscillating increase is seen in the thickness of the film deposited on nanoparticles. Also, it is shown that the uniformity of the deposited film is dependent on the rotation velocity of nanoparticles. Generally, the obtained results imply that the sphericity of nanoparticles and uniformity of the film coated on them are controllable by the magnitude and orientation of the magnetic field.

Studies with Laser Cooled Atoms and Single Molecules

DTIC Science & Technology

2007-09-01

between soda lime glass slides. The bond-setting time can be tailored to allow time for precision optical alignment. We also extended our previous single...This method achieves 100% successful bonding rates between soda lime glass slides. The bond-setting time and be can tailored to allow time for...simple method to bond optical components using silica nanoparticle sol-gel chemistry. The silica nanoparticles polymerize into highly branched

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.

Gold nanotriangles decorated with superparamagnetic iron oxide nanoparticles: a compositional and microstructural study

DOE PAGES

Hachtel, J. A.; Yu, S.; Lupini, A. R.; ...

2016-03-11

The combination of iron oxide and gold in a single nanoparticle results in both magnetic and plasmonic properties that can stimulate novel applications in bio-sensing, medical imaging, or therapeutics. Microwave assisted heating allows the fabrication of multi-component, multi-functional nanostructures by promoting selective heating at desired sites. Recently, we reported a microwave-assisted polyol route yielding gold nanotriangles decorated with iron oxide nanoparticles. Here, we present an in-depth microstructural and compositional characterization of the system by using scanning transmission electron microscopy (STEM) and electron energy loss (EELS) spectroscopy. A method to remove the iron oxide nanoparticles from the gold nanocrystals and somemore » insights on crystal nucleation and growth mechanisms are also provided.« less

Methods for purifying and detoxifying sodium dodecyl sulfate-stabilized polyacrylate nanoparticles.

PubMed

Garay-Jimenez, Julio C; Young, Ashley; Gergeres, Danielle; Greenhalgh, Kerriann; Turos, Edward

2008-06-01

Recent research in our laboratory has centered on studies of polyacrylate and polyacrylamide nanoparticle emulsions for use in antibiotic delivery. Our goal is to develop these nanoparticle emulsions for treatment of life-threatening bacterial infections such as those caused by methicillin-resistant Staphylococcus aureus. For this intended application it is necessary to ensure that the biological activity of the emulsion is due only to the drug attached to the polymeric chain and not to any extraneous components. To investigate this we evaluated cytotoxicity and microbiological activity of the nanoparticle emulsions before and after purification by centrifugation, dialysis, and gel filtration. Depending on the amount of surfactant used, all or most of the microbial and cellular toxicity can be removed by a simple purification procedure.

Biochemical changes in cyanobacteria during the synthesis of silver nanoparticles.

PubMed

Cepoi, L; Rudi, L; Chiriac, T; Valuta, A; Zinicovscaia, I; Duca, Gh; Kirkesali, E; Frontasyeva, M; Culicov, O; Pavlov, S; Bobrikov, I

2015-01-01

The methods of synthesis of silver (Ag) nanoparticles by the cyanobacteria Spirulina platensis and Nostoc linckia were studied. A complex of biochemical, spectral, and analytical methods was used to characterize biomass and to assess changes in the main components of biomass (proteins, lipids, carbohydrates, and phycobilin) during nanoparticle formation. The size and shape of Ag nanoparticles in the biomass of both types of cyanobacteria were determined. Neutron activation analysis was used to study the accumulation dynamics of the Ag quantity. The analytical results suggest that the major reduction of Ag concentration in solutions and the increase in biomass occur within the first 24 h of experiments. While in this time interval minor changes in the N. linckia and S. platensis biomass took place, a significant reduction of the levels of proteins, carbohydrates, and phycobiliproteins in both cultures and of lipids in S. platensis was observed after 48 h. At the same time, the antiradical activity of the biomass decreased. The obtained results show the necessity of determining the optimal conditions of the interaction between the biomass and the solution containing Ag ions that would allow nanoparticle formation without biomass degradation at the time of Ag nanoparticle formation by the studied cyanobacteria.

Nanoparticles in Medicine: Selected Observations and Experimental Caveats

PubMed Central

Thomsen, Sharon; Pearce, John A.; Giustini, Andrew; Hoopes, P. Jack

2014-01-01

Medically useful nanoparticles measure 1-100 nm in at least one dimension and are engineered and manufactured for specific diagnostic and treatment applications. Most nanoparticles used currently used in medicine are engineered and manufactured for specific purposes. Medically significant nanoparticles are composed of a 1) central core that is usually the medically active component, 2) one or more layers of organic or inorganic materials that forms a capsule (corona) covering the core and 3) an outer surface layer that interacts with the environment and/or targeted cells and tissues. Effective nanoparticle function in the living, intact animal or human requires electrochemical stability necessary to bypass the reticuloendothelial system (RES) and avoid filtration through the renal glomerulus into the urine. Nanoparticles are present in “natural” as well as the manufacturing and clinical environments thus could pose as significant toxins because of their small sizes, their chemical and drug content and potential effect of causing long term disease including allergies, chronic inflammation and cancer. Currently published studies have focused on the effects of nanoparticles on cells in the extremely artificial environments of cell cultures. More clinical and preclinical studies documenting the short term and long term effects nanoparticle in the intact experimental animal and human are needed. PMID:25301992

Synthesis and factorial design applied to a novel chitosan/sodium polyphosphate nanoparticles via ionotropic gelation as an RGD delivery system.

PubMed

Kiilll, Charlene Priscila; Barud, Hernane da Silva; Santagneli, Sílvia Helena; Ribeiro, Sidney José Lima; Silva, Amélia M; Tercjak, Agnieszka; Gutierrez, Junkal; Pironi, Andressa Maria; Gremião, Maria Palmira Daflon

2017-02-10

Chitosan nanoparticles have been extensively studied for both drug and protein/peptide delivery. The aim of this study was to develop an optimized chitosan nanoparticle, by ionotropic gelation method, using 3 2 full factorial design with a novel polyanion, sodium polyphosphate, well known under the trade name Graham salt. The effects of these parameters on the particle size, zeta potential, and morphology and association efficiency were investigated. The optimized nanoparticles showed an estimated size of 166.20±1.95nm, a zeta potential of 38.7±1.2mV and an efficacy of association of 97.0±2.4%. The Atomic Force Microscopy (AFM) and Scanning Electronic Microscopy (SEM) revealed spherical nanoparticles with uniform size. Molecular interactions among the components of the nanoparticles and peptide were evaluated by Fourier Transform Infrared Spectra (FTIR) and Differential Scanning Calorimetry (DSC). The obtained results indicated that, the developed nanoparticles demonstrated high biocompatible, revealing no or low toxicity in the human cancer cell line (Caco-2). In conclusion, this work provides parameters that contribute to production of chitosan nanoparticles and sodium polyphosphate with desirable size, biocompatible and enabling successful use for protein/peptides delivery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Magnetic Nanoparticles for Cancer Diagnosis and Therapy

PubMed Central

Yigit, Mehmet V.; Moore, Anna

2013-01-01

Nanotechnology is evolving as a new field that has a potentially high research and clinical impact. Medicine, in particular, could benefit from nanotechnology, due to emerging applications for noninvasive imaging and therapy. One important nanotechnological platform that has shown promise includes the so-called iron oxide nanoparticles. With specific relevance to cancer therapy, iron oxide nanoparticle-based therapy represents an important alternative to conventional chemotherapy, radiation, or surgery. Iron oxide nanoparticles are usually composed of three main components: an iron core, a polymer coating, and functional moieties. The biodegradable iron core can be designed to be superparamagnetic. This is particularly important, if the nanoparticles are to be used as a contrast agent for noninvasive magnetic resonance imaging (MRI). Surrounding the iron core is generally a polymer coating, which not only serves as a protective layer but also is a very important component for transforming nanoparticles into biomedical nanotools for in vivo applications. Finally, different moieties attached to the coating serve as targeting macromolecules, therapeutics payloads, or additional imaging tags. Despite the development of several nanoparticles for biomedical applications, we believe that iron oxide nanoparticles are still the most promising platform that can transform nanotechnology into a conventional medical discipline. PMID:22274558

[Study on liver targeted drug delivery system of the effective anticancer component from Bolbstemma paniculatum].

PubMed

Sun, Yi-Yi; Ll, Tong-Hui; Tang, Chen-Kang; Zhu, Zi-Ping; Chi, Qun; Hou, Shi-Xiang

2005-06-01

To study the liver targeted drug delivery system of TBMS--the effective anticancer component from Bolbstemma paniculatum, and to discuss the system's function of decreasing toxicity. BCA was used as carrier material. The preparation through overall feedback dynamic techniques. The properties of preparation and toxicology were also technology of nanoparticles was optimized studied. Thenanoparticles' targeting in mice vivo was observed with transmission electron microscopy. The function of decreasing toxicity was researched by the XXTX-2000 automatic quantitative analysis management system. D50 was 0.68 microm. Drug-loading rate and entrapment rate were 37.3% and 88.6% respectively. The release in vitro accorded with Weibull equation. The reaching release balance time and the t 1/2 extended 26 times and 19 times respectively comparing with injection. Nanoparticles mainly distributed in liver tissue. Their toxicity to lung and liver was evidently lower than injection. Nanoparticles' LD50 exceeded injection's by 13.5% and their stimulus was much lower than injection. The TBMS can be targeted to liver by liver targeted drug delivery system. At the same time, the problem about the toxicity hindering clinical application could be solved, which lays the foundation for the further studies on TBMS.

Surface modification of upconverting nanoparticles by layer-by-layer assembled polyelectrolytes and metal ions.

PubMed

Palo, Emilia; Salomäki, Mikko; Lastusaari, Mika

2017-12-15

Modificating and protecting the upconversion luminescence nanoparticles is important for their potential in various applications. In this work we demonstrate successful coating of the nanoparticles by a simple layer-by-layer method using negatively charged polyelectrolytes and neodymium ions. The layer fabrication conditions such as number of the bilayers, solution concentrations and selected polyelectrolytes were studied to find the most suitable conditions for the process. The bilayers were characterized and the presence of the desired components was studied and confirmed by various methods. In addition, the upconversion luminescence of the bilayered nanoparticles was studied to see the effect of the surface modification on the overall intensity. It was observed that with selected deposition concentrations the bilayer successfully shielded the particle resulting in stronger upconversion luminescence. The layer-by-layer method offers multiple possibilities to control the bilayer growth even further and thus gives promises that the use of upconverting nanoparticles in applications could become even easier with less modification steps in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

Exploitation of endophytic fungus, Guignardia mangiferae for extracellular synthesis of silver nanoparticles and their in vitro biological activities.

PubMed

Balakumaran, M D; Ramachandran, R; Kalaichelvan, P T

2015-09-01

The aim of this study was to synthesize highly biocompatible and functionalized silver nanoparticles using endophytic fungi isolated from the leaves of medicinal plants. Among 13 fungi tested, the isolate, Guignardia mangiferae (Bios PTK 4) extracellularly synthesized well-dispersed and extremely stable silver nanoparticles under optimized reaction conditions within 12 h. These nanoparticles were characterized by HR-TEM, SAED, XRD and EDX analyses. G. mangiferae synthesized 5-30 nm sized, spherical shaped silver nanoparticles. Effect of pH on the antibacterial activity of silver nanoparticles was studied using well diffusion assay; on the basis of particle stability and antibacterial activity, pH 7 was found to be optimum. The leakage of intracellular components has clearly demonstrated that silver nanoparticles damage the bacterial cells by formation of pores, which affect the membrane permeability and finally leads to cell death. In addition, silver nanoparticles exhibited excellent antifungal activity against plant pathogenic fungi. Cytotoxic effects of silver nanoparticles showed IC50 values of 63.37, 27.54 and 23.84 μg/mL against normal African monkey kidney (Vero), HeLa (cervical) and MCF-7 (breast) cells, respectively, at 24 h incubation period. Thus, the obtained results convincingly suggest that silver nanoparticles synthesized from G. mangiferae are highly biocompatible and have wider applicability and they could be explored as promising candidates for a variety of biomedical/pharmaceutical and agricultural applications. Copyright © 2015 Elsevier GmbH. All rights reserved.

Exogenous iron redistribution between brain and spleen after the administration of the 57Fe3O4 ferrofluid into the ventricle of the brain

NASA Astrophysics Data System (ADS)

Gabbasov, Raul; Polikarpov, Dmitry; Cherepanov, Valery; Chuev, Michael; Mischenko, Ilya; Loginiva, Nadezhda; Loseva, Elena; Nikitin, Maxim; Panchenko, Vladislav

2017-04-01

Iron clearance pathways after the injection of 57Fe3O4-based dextran-stabilized ferrofluid into the brain ventricles were studied by Mössbauer spectroscopy and histologically. The nanoparticles appeared in spleen tissues within 3 h after transcranial injection. We separated and independently estimated concentrations of iron encapsulated in nanoparticles and iron encapsulated in proteins in the all rat organs. It was found that the dextran coated initial nanoparticles of the ferrofluid disintegrated in the brain into separate superparamagnetic nanoparticles within a week after the injection.The nanoparticles completely exited from the brain in a few weeks. The exogenous iron appeared in the spleen in 3 h after the injection and remained in the spleen for more than month. The appearance of additional component in Mössbauer spectra of spleen samples revealed a fundamental difference in the mechanisms of processing of iron nanoparticles in this organ, which was also confirmed by histological examination.

Metal nanoparticles (other than gold or silver) prepared using plant extracts for medical applications

NASA Astrophysics Data System (ADS)

Pasca, Roxana-Diana; Santa, Szabolcs; Racz, Levente Zsolt; Racz, Csaba Pal

2016-12-01

There are many modalities to prepare metal nanoparticles, but the reducing of the metal ions with plant extracts is one of the most promising because it is considerate less toxic for the environment, suitable for the use of those nanoparticles in vivo and not very expensive. Various metal ions have been already studied such as: cobalt, copper, iron, platinum, palladium, zinc, indium, manganese and mercury and the number of plant extracts used is continuously increasing. The prepared systems were characterized afterwards with a great number of methods of investigation: both spectroscopic (especially UV-Vis spectroscopy) and microscopic (in principal, electron microscopy-TEM) methods. The applications of the metal nanoparticles obtained are diverse and not completely known, but the medical applications of such nanoparticles occupy a central place, due to their nontoxic components, but some diverse industrial applications do not have to be forgotten.

[Oxidative Stress Derived from Airborne Fine and Ultrafine Particles and the Effects on Brain-Nervous System: Part 2].

PubMed

Sagai, Masaru; Tin Win-Shwe, Tin

2015-01-01

Traffic-related air pollution is a major contributor to urban air pollution. Diesel exhaust (DE) is its most important component of near-road and urban air pollutions and is commonly used as a surrogate model of air pollution in health effects studies. In particular, diesel exhaust particles (DEPs) and nanoparticles in DEPs are the components considered hazardous for health. It is widely known that exposure to DEPs is associated with mortality caused by respiratory and cardiovascular diseases. Recently, evidence has been accumulating showing that DEPs and nanoparticles may cause neurodegenerative disorders. Here, we introduce evidence suggesting their association with these disorders. The chemical components and the translocation of DEPs and nanoparticles to the brain are described in part 1. In part 2, we introduce the mechanism of development of neurodegenerative diseases such as stroke, Alzheimer's disease, and Parkinson's disease via oxidative stress and inflammatory events. Furthermore, there are many lines of epidemiological evidence showing that the particulates impair cognitive function and ability of memory through oxidative and inflammatory events in the brain. These lines of evidences are supported by many animal experiments on neurological disorders.

Metal nanoparticle deposited inorganic nanostructure hybrids, uses thereof and processes for their preparation

DOEpatents

Tenne, Reshef; Tsverin, Yulia; Burghaus, Uwe; Komarneni, Mallikharjuna Rao

2016-01-26

This invention relates to a hybrid component comprising at least one nanoparticle of inorganic layered compound (in the form of fullerene-like structure or nanotube), and at least one metal nanoparticle, uses thereof as a catalyst, (e.g. photocatalysis) and processes for its preparation.

Electrical bistability in conductive hybrid composites of doped polyaniline nanofibers-gold nanoparticles capped with dodecane thiol.

PubMed

Borriello, A; Agoretti, P; Cassinese, A; D'Angelo, P; Mohanraj, G T; Sanguigno, L

2009-11-01

A novel electrical bistable hybrid nanocomposite based on doped Polyaniline nanofibers with 1-Dodecanethiol-protected Gold nanoparticle (PAni.AuDT), 3-4 nm in size, as the conductive component and polystyrene as polymer matrix was prepared. The structural morphology of the composite and the dispersion of nanoparticles inside it were evaluated using Transmission Electron Microscopy (TEM). The thermal stability and the ratio Polyaniline/Gold nanoparticles in the composite were determined by using thermogravimetric analysis. The electrical bistability of the PAni.AuDT-PS composite, the influence of the dispersion of the PAni.AuDT conductive network and the basic operation mechanism, have been assessed by measuring the electrical response of planar device architectures, also as a function of the environmental temperature (in the range 200 K < T < 360 K). The basic operation mechanism of the hybrid compound has been then correlated to the combined action of the thermally-induced scattering of charge carriers and the thermal contraction of the hosting polymeric matrix. Moreover, the right compromise between these two effects in terms of the most efficient bistability has been studied, founding the concentration of the conductive component which optimizes the device on-off ratio (I(on)/ I(off)).

Formation of highly structured cubic micellar lipid nanoparticles of soy phosphatidylcholine and glycerol dioleate and their degradation by triacylglycerol lipase.

PubMed

Wadsäter, Maria; Barauskas, Justas; Nylander, Tommy; Tiberg, Fredrik

2014-05-28

Lipid nanoparticles of reversed internal phase structures, such as cubic micellar (I2) structure show good drug loading ability of peptides and proteins as well as some small molecules. Due to their controllable small size and inner morphology, such nanoparticles are suitable for drug delivery using several different administration routes, including intravenous, intramuscular, and subcutaneous injection. A very interesting system in this regard, is the two component soy phosphatidylcholine (SPC)/glycerol dioleate (GDO) system, which depending on the ratio of the lipid components form a range of reversed liquid crystalline phases. For a 50/50 (w/w) ratio in excess water, these lipids have been shown to form a reversed cubic micellar (I2) phase of the Fd3m structure. Here, we demonstrate that this SPC/GDO phase, in the presence of small quantities (5-10 wt %) of Polysorbate 80 (P80), can be dispersed into nanoparticles, still with well-defined Fd3m structure. The resulting nanoparticle dispersion has a narrow size distribution and exhibit good long-term stability. In pharmaceutical applications, biodegradation pathways of the drug delivery vehicles and their components are important considerations. In the second part of the study we show how the structure of the particles evolves during exposure to a triacylglycerol lipase (TGL) under physiological-like temperature and pH. TGL catalyzes the lipolytic degradation of acylglycerides, such as GDO, to monoglycerides, glycerol, and free fatty acids. During the degradation, the interior phase of the particles is shown to undergo continuous phase transitions from the reversed I2 structure to structures of less negative curvature (2D hexagonal, bicontinuous cubic, and sponge), ultimately resulting in the formation of multilamellar vesicles.

Chemical synthesis and structural characterization of small AuZn nanoparticles

NASA Astrophysics Data System (ADS)

Juárez-Ruiz, E.; Pal, U.; Lombardero-Chartuni, J. A.; Medina, A.; Ascencio, J. A.

2007-03-01

In this paper, we report the aqueous synthesis of bimetallic Au-Zn nanoparticles of different compositions by the simultaneous reduction technique. The stability and atomic configuration of the particles are studied through high-resolution transmission electron microscopy (HRTEM) and UV-Vis optical absorption techniques. Depending on the composition, small bimetallic nanoparticles of 1 15 nm in size were obtained. The average size and size distribution of the bimetallic nanoparticles are seen to be critically dependent on the atomic ratio of the constituting elements Au and Zn. While a 1:1 atomic proportion of Au and Zn produced most stable nanoparticles of smallest average size, nanoparticles produced with higher content of either of the component elements are unstable, inducing agglomeration and coalescence to form elongated structures with uneven morphologies. Au3Zn1 nanoparticles followed a directional growth pattern, producing bimetallic nanorods with multiple crystalline domains. Interestingly, in these rod-like nanostructures, the domains are in well array of solid solution-like bimetallic and pure mono-metallic regions alternatively. Such nanostructures with uneven morphology and compositions might show distinct catalytic selectivity in chemical reactions.

Gold nanoparticles based imaging technique and drug delivery for the detection and treatment of atherosclerotic vascular disease

NASA Astrophysics Data System (ADS)

Ankri, Rinat; Leshem-Lev, Dorit; Lev, Eli I.; Motiei, Menachem; Hochhauser, Edith; Fixler, Dror

2016-03-01

In our study we aim to develop a new, simple and non-invasive method to detect and to treat atherosclerosis. We use gold nanoparticles (GNPs) combined with the diffusion reflection (DR) method to demonstrate the detection of vulnerable atherosclerotic plaques. Our method is based on the fact that macrophages are a major component in the vulnerable plaque and are able to uptake metal nanoparticles that can be discovered by the DR system. Moreover, it is well known that high density lipoprotein (HDL) reduces ASVD by inhibiting pro-inflammatory factors, enabling the specific treatment of atherosclerosis.

First-principles configurational thermodynamics of alloyed nanoparticles with adsorbates

NASA Astrophysics Data System (ADS)

Wang, Lin-Lin; Tan, Teck L.; Johnson, Duane D.

2014-03-01

Transition-metal, alloyed nanoparticles (NPs) are key components in current and emerging energy technologies because they are found to improve catalytic activity and selectivity for many energy-conversion processes. However, thermodynamic investigations of the compositional profile of alloyed nanoparticles, which determines their catalytic properties, have been limited mostly to NP core-shell preference without the presence of adsorbates. Here, by extending cluster expansion methods to treat both alloyed nanoparticles and adsorbates, we study the configurational thermodynamics of bimetallic NPs under chemically reactive conditions, using databases from density functional theory calculations. With a few examples, we show that such simulations can provide information needed for rational design of NP catalysts. DOE/BES under DE-FG02-03ER15476 (Catalysis) and DE-AC02-07CH11358 at the Ames Laboratory.

Chiral nanoparticles in singular light fields

PubMed Central

Vovk, Ilia A.; Baimuratov, Anvar S.; Zhu, Weiren; Shalkovskiy, Alexey G.; Baranov, Alexander V.; Fedorov, Anatoly V.; Rukhlenko, Ivan D.

2017-01-01

The studying of how twisted light interacts with chiral matter on the nanoscale is paramount for tackling the challenging task of optomechanical separation of nanoparticle enantiomers, whose solution can revolutionize the entire pharmaceutical industry. Here we calculate optical forces and torques exerted on chiral nanoparticles by Laguerre–Gaussian beams carrying a topological charge. We show that regardless of the beam polarization, the nanoparticles are exposed to both chiral and achiral forces with nonzero reactive and dissipative components. Longitudinally polarized beams are found to produce chirality densities that can be 109 times higher than those of transversely polarized beams and that are comparable to the chirality densities of beams polarized circularly. Our results and analytical expressions prove useful in designing new strategies for mechanical separation of chiral nanoobjects with the help of highly focussed beams. PMID:28378842

Methods for Purifying and Detoxifying Sodium Dodecyl Sulfate-Stabilized Polyacrylate Nanoparticles

PubMed Central

Garay-Jimenez, Julio C.; Young, Ashley; Gergeres, Danielle; Greenhalgh, Kerriann; Turos, Edward

2008-01-01

Recent research in our laboratory has centered on studies of polyacrylate and polyacrylamide nanoparticle emulsions for use in antibiotic delivery. Our goal is to develop these nanoparticle emulsions for treatment of life-threatening bacterial infections such as those caused by methicillin-resistant Staphylococcus aureus (MRSA). For this intended application, it is necessary to ensure that the biological activity of the emulsion is due only to the drug attached to the polymeric chain, rather than to any extraneous components. To investigate this, we evaluated cytotoxicity and microbiological activity of the nanoparticle emulsions before and after purification by centrifugation, dialysis, and gel filtration. Depending on the amount of surfactant used, all or most of the microbial and cellular toxicity can be removed by a simple purification procedure. PMID:18472305

Iron Oxide Nanoradiomaterials: Combining Nanoscale Properties with Radioisotopes for Enhanced Molecular Imaging

PubMed Central

Pellico, Juan; Fernández-Barahona, Irene; Bhavesh, Riju; Ruiz-Cabello, Jesús

2017-01-01

The combination of the size-dependent properties of nanomaterials with radioisotopes is emerging as a novel tool for molecular imaging. There are numerous examples already showing how the controlled synthesis of nanoparticles and the incorporation of a radioisotope in the nanostructure offer new features beyond the simple addition of different components. Among the different nanomaterials, iron oxide-based nanoparticles are the most used in imaging because of their versatility. In this review, we will study the different radioisotopes for biomedical imaging, how to incorporate them within the nanoparticles, and what applications they can be used for. Our focus is directed towards what is new in this field, what the nanoparticles can offer to the field of nuclear imaging, and the radioisotopes hybridized with nanomaterials for use in molecular imaging. PMID:29358900

Chiral nanoparticles in singular light fields

NASA Astrophysics Data System (ADS)

Vovk, Ilia A.; Baimuratov, Anvar S.; Zhu, Weiren; Shalkovskiy, Alexey G.; Baranov, Alexander V.; Fedorov, Anatoly V.; Rukhlenko, Ivan D.

2017-04-01

The studying of how twisted light interacts with chiral matter on the nanoscale is paramount for tackling the challenging task of optomechanical separation of nanoparticle enantiomers, whose solution can revolutionize the entire pharmaceutical industry. Here we calculate optical forces and torques exerted on chiral nanoparticles by Laguerre-Gaussian beams carrying a topological charge. We show that regardless of the beam polarization, the nanoparticles are exposed to both chiral and achiral forces with nonzero reactive and dissipative components. Longitudinally polarized beams are found to produce chirality densities that can be 109 times higher than those of transversely polarized beams and that are comparable to the chirality densities of beams polarized circularly. Our results and analytical expressions prove useful in designing new strategies for mechanical separation of chiral nanoobjects with the help of highly focussed beams.

Solid Lipid Nanoparticles of Guggul Lipid as Drug Carrier for Transdermal Drug Delivery

PubMed Central

Gaur, Praveen Kumar; Mishra, Shikha; Purohit, Suresh

2013-01-01

Diclofenac sodium loaded solid lipid nanoparticles (SLNs) were formulated using guggul lipid as major lipid component and analyzed for physical parameters, permeation profile, and anti-inflammatory activity. The SLNs were prepared using melt-emulsion sonication/low temperature-solidification method and characterized for physical parameters, in vitro drug release, and accelerated stability studies, and formulated into gel. Respective gels were compared with a commercial emulgel (CEG) and plain carbopol gel containing drug (CG) for ex vivo and in vivo drug permeation and anti-inflammatory activity. The SLNs were stable with optimum physical parameters. GMS nanoparticle 1 (GMN-1) and stearic acid nanoparticle 1 (SAN-1) gave the highest in vitro drug release. Guggul lipid nanoparticle gel 3 (GLNG-3) showed 104.68 times higher drug content than CEG in receptor fluid. The enhancement ratio of GLNG-3 was 39.43 with respect to CG. GLNG-3 showed almost 8.12 times higher C max than CEG at 4 hours. The AUC value of GLNG-3 was 15.28 times higher than the AUC of CEG. GLNG-3 showed edema inhibition up to 69.47% in the first hour. Physicochemical properties of major lipid component govern the properties of SLN. SLN made up of guggul lipid showed good physical properties with acceptable stability. Furthermore, it showed a controlled drug release profile along with a promising permeation profile. PMID:24058913

Interactions between DPPC as a component of lung surfactant and amorphous silica nanoparticles investigated by HILIC-ESI-MS.

PubMed

Silina, Yuliya E; Welck, Jennifer; Kraegeloh, Annette; Koch, Marcus; Fink-Straube, Claudia

2016-09-01

This paper reports a rapid HILIC-ESI-MS assay to quantify dipalmitoylphosphatidylcholine (DPPC) as component of lung surfactant for nanosafety studies. The technique was used to investigate the concentration-dependent sorption of DPPC to two-sizes of amorphous SiO2 nanoparticles (SiO2-NPs) in a MeOH:H2O (50/50v/v) mixture and in cell culture medium. In MeOH:H2O (50/50v/v), the sorption of DPPC was positively correlated with the nanoparticles concentration. A substantial affinity of small amorphous SiO2-NPs (25nm) to DPPC standard solution compared to bigger SiO2-NPs (75nm) was not confirmed for biological specimens. After dispersion of SiO2-NPs in DPPC containing cell culture medium, the capacity of the SiO2-NPs to bind DPPC was reduced in comparison to a mixture of MeOH:H2O (50/50v/v) regardless from the nanoparticles size. Furthermore, HILIC-ESI-MS revealed that A549 cells internalized DPPC during growth in serum containing medium complemented with DPPC. This finding was in a good agreement with the potential of alveolar type II cells to recycle surfactant components. Binding of lipids present in the cell culture medium to amorphous SiO2-NPs was supported by means of HILIC-ESI-MS, TEM and ICP-MS independently. Copyright © 2016 Elsevier B.V. All rights reserved.

Widespread Nanoparticle-Assay Interference: Implications for Nanotoxicity Testing

PubMed Central

Ong, Kimberly J.; MacCormack, Tyson J.; Clark, Rhett J.; Ede, James D.; Ortega, Van A.; Felix, Lindsey C.; Dang, Michael K. M.; Ma, Guibin; Fenniri, Hicham; Veinot, Jonathan G. C.; Goss, Greg G.

2014-01-01

The evaluation of engineered nanomaterial safety has been hindered by conflicting reports demonstrating differential degrees of toxicity with the same nanoparticles. The unique properties of these materials increase the likelihood that they will interfere with analytical techniques, which may contribute to this phenomenon. We tested the potential for: 1) nanoparticle intrinsic fluorescence/absorbance, 2) interactions between nanoparticles and assay components, and 3) the effects of adding both nanoparticles and analytes to an assay, to interfere with the accurate assessment of toxicity. Silicon, cadmium selenide, titanium dioxide, and helical rosette nanotubes each affected at least one of the six assays tested, resulting in either substantial over- or under-estimations of toxicity. Simulation of realistic assay conditions revealed that interference could not be predicted solely by interactions between nanoparticles and assay components. Moreover, the nature and degree of interference cannot be predicted solely based on our current understanding of nanomaterial behaviour. A literature survey indicated that ca. 95% of papers from 2010 using biochemical techniques to assess nanotoxicity did not account for potential interference of nanoparticles, and this number had not substantially improved in 2012. We provide guidance on avoiding and/or controlling for such interference to improve the accuracy of nanotoxicity assessments. PMID:24618833

Are Australians concerned about nanoparticles? A comparative analysis with established and emerging environmental health issues.

PubMed

Capon, Adam; Rolfe, Margaret; Gillespie, James; Smith, Wayne

2015-02-01

Introducing new technologies into society raises considerable public concern. We determine the public concern about nanoparticles, and compare this concern to other environmental health issues such as wind farms and coal seam gas production. A repeat cross sectional survey examining views on environmental health issues, risk, chemicals and trust was undertaken in more than 1,300 Australian residents in 2000 and 2013. Logistic regression and principal component analysis was used to investigate predictors of nanoparticle concern and identify a component structure for environmental health issues that could explain a trend of future nanoparticle concern. Australians have a relatively low level of concern about the risks of nanoparticles to health when compared to their concerns about other environmental health issues. Items associated with concern included gender, a general wish to avoid chemicals and possibly trust in politicians. Concern over nanoparticles clustered with similar views on technological risks. Current public concern over the risks of nanoparticles is low. However, a reframing of the issue towards 'chemicals' is likely to have a negative effect on risk perceptions. This paper raises questions about appropriate channels for the effective communication of risk. © 2015 Public Health Association of Australia.

Aloe vera Induced Biomimetic Assemblage of Nucleobase into Nanosized Particles

PubMed Central

Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

2012-01-01

Aim Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera leaf extract. Methodology The 5-FU nano- particles synthesized by using Aloe vera leaf extract were characterized by UV, FT-IR and fluorescence spectroscopic techniques. The size and shape of the synthesized nanoparticles were determined by TEM, while crystalline nature of 5-FU particles was established by X-ray diffraction study. The cytotoxic effects of 5-FU nanoparticles were assessed against HT-29 and Caco-2 (human adenocarcinoma colorectal) cell lines. Results Transmission electron microscopy and atomic force microscopic techniques confirmed nano-size of the synthesized particles. Importantly, the nano-assembled 5-FU retained its anticancer action against various cancerous cell lines. Conclusion In the present study, we have explored the potential of biomimetic synthesis of nanoparticles employing organic molecules with the hope that such developments will be helpful to introduce novel nano-particle formulations that will not only be more effective but would also be devoid of nano-particle associated putative toxicity constraints. PMID:22403622

Fungus-mediated biological synthesis of gold nanoparticles: potential in detection of liver cancer

PubMed Central

Chauhan, Arun; Zubair, Swaleha; Tufail, Saba; Sherwani, Asif; Sajid, Mohammad; Raman, Suri C; Azam, Amir; Owais, Mohammad

2011-01-01

Background Nanomaterials are considered to be the pre-eminent component of the rapidly advancing field of nanotechnology. However, developments in the biologically inspired synthesis of nanoparticles are still in their infancy and consequently attracting the attention of material scientists throughout the world. Keeping in mind the fact that microorganism-assisted synthesis of nanoparticles is a safe and economically viable prospect, in the current study we report Candida albicans-mediated biological synthesis of gold nanoparticles. Methods and results Transmission electron microscopy, atomic force microscopy, and various spectrophotometric analyses were performed to characterize the gold nanoparticles. The morphology of the synthesized gold particles depended on the abundance of C. albicans cytosolic extract. Transmission electron microscopy, nanophox particle analysis, and atomic force microscopy revealed the size of spherical gold nanoparticles to be in the range of 20–40 nm and nonspherical gold particles were found to be 60–80 nm. We also evaluated the potential of biogenic gold nanoparticles to probe liver cancer cells by conjugating them with liver cancer cell surface-specific antibodies. The antibody-conjugated gold particles were found to bind specifically to the surface antigens of the cancer cells. Conclusion The antibody-conjugated gold particles synthesized in this study could successfully differentiate normal cell populations from cancerous cells. PMID:22072868

Clusterin in the protein corona plays a key role in the stealth effect of nanoparticles against phagocytes.

PubMed

Aoyama, Michihiko; Hata, Katsutomo; Higashisaka, Kazuma; Nagano, Kazuya; Yoshioka, Yasuo; Tsutsumi, Yasuo

2016-11-25

In biological fluids, nanoparticles interact with biological components such as proteins, and a layer called the "protein corona" forms around the nanoparticles. It is believed that the composition of the protein corona affects the cellular uptake and in vivo biodistribution of nanoparticles; however, the key proteins of the protein corona that control the biological fate of nanoparticles remain unclear. Recently, it was reported that clusterin binding to pegylated nanoparticles is important for the stealth effect of pegylated nanoparticles in phagocytes. However, the effect of clusterin on non-pegylated nanoparticles is unknown, although it is known that clusterin is present in the protein corona of non-pegylated nanoparticles. Here, we assessed the stealth effect of clusterin in the corona of non-pegylated silver nanoparticles and silica nanoparticles. We found that serum- and plasma-protein corona inhibited the cellular uptake of silver nanoparticles and silica nanoparticles in phagocytes and that the plasma-protein corona showed a greater stealth effect compared with the serum-protein corona. Clusterin was present in both the serum- and plasma-protein corona, but was present at a higher level in the plasma-protein corona than in the serum-protein corona. Clusterin binding to silver nanoparticles and silica nanoparticles suppressed the cellular uptake of nanoparticles in human macrophage-like cells (THP-1 cells). Although further studies are required to determine how clusterin suppresses non-specific cellular uptake in phagocytes, our data suggest that clusterin plays a key role in the stealth effect of not only pegylated nanoparticles but also non-pegylated nanoparticles. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of TiO, nanoparticles on the interface in the PET-rubber composites.

PubMed

Vladuta, Cristina; Andronic, Luminita; Duta, Anca

2010-04-01

Usually, ceramic powders (SiO2, ZnO) are used as fillers for enhancing rubber mechanical strength. Poly-ethylene terephthalate (PET)-rubber nanocomposites were prepared by compression molding using titanium oxide (TiO2) nanoparticles as low content fillers (<2% wt). The interface properties of PET-rubber nanocomposites were studied before and after keeping the samples under UV-radiation for a week. UV-radiation has interesting potential for the photochemical modification of polymers and TiO2. The influence of UV radiation on the properties of the interface polymer-TiO2 nanoparticles was evaluated. The impact of nanoparticle aggregates on the nanometer to micrometer organization of PET-rubber composites was studied with Atomic Force Microscopy (AFM). The interface properties were explained by measuring the contact angles and surface tensions. The interactions between components of nanocomposites were investigated with Fourier Transform-Infrared (FTIR) and the effects of TiO2 nanoparticle on the interfaces and composites crystalline structure were evaluated by X-ray diffraction (XRD). The results proved that the TiO2 nanoparticles, in different weight percentages, did not alter the nanocomposites crystallinity or the average crystallites size, but improve the interface properties.

Modification of nanostructured calcium carbonate for efficient gene delivery.

PubMed

Zhao, Dong; Wang, Chao-Qun; Zhuo, Ren-Xi; Cheng, Si-Xue

2014-06-01

In this study, a facile method to modify nanostructured calcium carbonate (CaCO3) gene delivery systems by adding calcium phosphate (CaP) component was developed. CaCO3/CaP/DNA nanoparticles were prepared by the co-precipitation of Ca(2+) ions with plasmid DNA in the presence of carbonate and phosphate ions. For comparison, CaCO3/DNA nanoparticles and CaP/DNA co-precipitates were also prepared. The effects of carbonate ion/phosphate ion (CO3(2-)/PO4(3-)) ratio on the particle size and gene delivery efficiency were investigated. With an appropriate CO3(2-)/PO4(3-) ratio, the co-existence of carbonate and phosphate ions could control the size of co-precipitates effectively, and CaCO3/CaP/DNA nanoparticles with a decreased size and improved stability could be obtained. The in vitro gene transfections mediated by different nanoparticles in 293T cells and HeLa cells were carried out, using pGL3-Luc as a reporter plasmid. The gene transfection efficiency of CaCO3/CaP/DNA nanoparticles could be significantly improved as compared with CaCO3/DNA nanoparticles and CaP/DNA co-precipitates. The confocal microscopy study indicated that the cellular uptake and nuclear localization of CaCO3/CaP/DNA nanoparticles were significantly enhanced as compared with unmodified CaCO3/DNA nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

General rules for incorporating noble metal nanoparticles in organic solar cells

NASA Astrophysics Data System (ADS)

Ciesielski, A.; Switlik, D.; Szoplik, T.

2017-05-01

Over the recent years, the influence of the addition of noble metal nanoparticles (Au, Ag, Al, Cu) into the bulk heterojunction (BHJ) solar cells on their efficiency of visible sunlight absorption has been excessively studied. However, several detailed studies were focused on compounds with similar chemical structure, and thus similar optical and electric properties. Such approach provides little help when it comes to admixing metallic nanoparticles into new compound families with different properties. Moreover, theoretical approaches frequently tend to neglect the fact, that nanoparticles have different dispersion relation than bulk material, which may lead to false conclusions. In this work, we consider additional dispersion modes in the metal permittivity due to finite size of the nanoparticles. We use Maxwell-Garnet effective medium approach (EMA), combined with the transfer matrix method, as well as finite-difference time-domain (FDTD) simulations, to create a set of general rules for incorporating noble metal nanoparticles into the active layer. These principles, based on assumed basic properties of the active layer (e.g. real and imaginary part of refractive index, thickness) provide optimal material, size spectrum and fill factor of nanoparticle inclusions in order to ensure the best absorption enhancement. Our results show, that the optimal concentrations for silver nanoparticles are about 50% greater than those determined without taking into account additional components in the permittivity of the metal.

Acid-activatable oxidative stress-inducing polysaccharide nanoparticles for anticancer therapy.

PubMed

Yoo, Wooyoung; Yoo, Donghyuck; Hong, Eunmi; Jung, Eunkyeong; Go, Yebin; Singh, S V Berwin; Khang, Gilson; Lee, Dongwon

2018-01-10

Drug delivery systems have been extensively developed to enhance the therapeutic efficacy of drugs by altering their pharmacokinetics and biodistribution. However, the use of high quantities of drug delivery systems can cause toxicity due to their poor metabolism and elimination. In this study, we developed polysaccharide-based drug delivery systems which exert potent therapeutic effects and could display synergistic therapeutic effects with drug payloads, leading to dose reduction. Cinnamaldehyde, a major component of cinnamon is known to induce anticancer activity by generating ROS (reactive oxygen species). We developed cinnamaldehyde-conjugated maltodextrin (CMD) as a polymeric prodrug of cinnamaldehyde and a drug carrier. Cinnamaldehyde was conjugated to the hydroxyl groups of maltodextrin via acid-cleavable acetal linkages, allowing facile formulation of nanoparticles and drug encapsulation. CMD nanoparticles induced acid-triggered ROS generation to induce apoptotic cell death. Camptothecin (CPT) was used as a model drug to investigate the potential of CMD nanoparticles as a drug carrier and also evaluate the synergistic anticancer effects with CMD nanoparticles. CPT-loaded CMD nanoparticles exhibited significantly higher anticancer activity than empty CMD nanoparticles and CPT alone in the study of mouse xenograft models, demonstrating the synergistic therapeutic effects of CMD with CPT. Taken together, we believe that CMD nanoparticles hold tremendous potential as a polymeric prodrug of cinnamaldehyde and a drug carrier in anticancer therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitation of Surface Coating on Nanoparticles Using Thermogravimetric Analysis.

PubMed

Dongargaonkar, Alpana A; Clogston, Jeffrey D

2018-01-01

Nanoparticles are critical components in nanomedicine and nanotherapeutic applications. Some nanoparticles, such as metallic nanoparticles, consist of a surface coating or surface modification to aid in its dispersion and stability. This surface coating may affect the behavior of nanoparticles in a biological environment, thus it is important to measure. Thermogravimetric analysis (TGA) can be used to determine the amount of coating on the surface of the nanoparticle. TGA experiments run under inert atmosphere can also be used to determine residual metal content present in the sample. In this chapter, the TGA technique and experimental method are described.

Tuning the dielectric properties of polystyrene/poly(vinylidene fluoride) blends by selectively localizing carbon black nanoparticles.

PubMed

Zhao, Xiaodong; Zhao, Jun; Cao, Jian-Ping; Wang, Xiaoyan; Chen, Min; Dang, Zhi-Min

2013-02-28

In this work, the dielectric properties of immiscible polystyrene (PS)/poly(vinylidene fluoride) (PVDF) blends are tuned by selectively localizing carbon black (CB) nanoparticles in different phases. The PS/PVDF blends have a wide window of cocontinuity (ca. 30-80 vol % in terms of the volume fraction of PS component (v(PS))). The selective localization of CB nanoparticles is achieved by using the masterbatch process during melt mixing. For the volume ratio PS/PVDF 1/1 and the volume fraction of CB nanoparticles (v(CB)) below but close to the percolation threshold (v(c)(CB)), the selective localization of CB nanoparticles in PVDF phase produces higher dielectric constant (ε) than that in PS phase, whereas the ε of the ternary mixtures without selective localization of fillers is in the middle. For the volume ratios PS/PVDF 1/2 and 2/1, the selective location of CB nanoparticles in different phases can be used to easily tune the system from conductive to insulating or inverse, which might have potential applications in industry. The fillers are found to be "fixed" in the masterbatch of PS or PVDF component and there is no migration of the fillers to another phase occurring during the further mixing process for the mixing time up to 30 min. Furthermore, the addition of CB nanoparticles to the polymer matrix is found to induce the brittle-ductile transition in the system and increase the compatibility between the immiscible PS and PVDF components, which should benefit the mechanical properties.

A preliminary study on the potency of nanofluids as the electro-active materials for nanoelectrofuel flow batteries

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

Kristiawan, B., E-mail: budi-k@uns.ac.id; Wijayanta, A. T., E-mail: agungtw@uns.ac.id; Juwana, W. E., E-mail: wibawa.ej@gmail.com

2016-03-29

This study presents a characterization of nanofluids as electroactive materials with dispersing metal oxide nanoparticles into aqueous polyelectrolytes of 20 wt.%, in particular, their electrochemical activites. The fundamental characterizations including X-ray diffraction, transmission electron microscopy, and Fourier ttransform iinfrared measurement were performed to ensure metal oxide component used in this work. Alumina (Al{sub 2}O{sub 3}) and copper oxide (CuO) nanoparticles of 0.5 vol.% in volume fraction were dispersed into Poly(diallyldimethylammonium chloride) solution (PDADMAC) and Poly(sodium 4-styrenesulfonate) (PSS), respectively. Alumina and copper oxide nanoparticles were dispersed into ionic solution with volume fraction of 0.5 vol.% by using two-step method. The generalmore » cyclic voltammetry measurement was used to analyze electrochemical behavior within three-electrode cell setup. The results show that PSS-based nanofluids demonstrate redox process. However, unclearly redox phenomenon was depicted PDADMAC-based nanofluids. Dispersing nanoparticles could shift pure ionic solution’s cyclic profile. It is clear that a significant impact on electrochemical behavior can be provided because of the existence metal oxide nanoparticles into polyelectrolyte solution.« less

Semiconductor assisted metal deposition for nanolithography applications

DOEpatents

Rajh, Tijana; Meshkov, Natalia; Nedelijkovic, Jovan M.; Skubal, Laura R.; Tiede, David M.; Thurnauer, Marion

2001-01-01

An article of manufacture and method of forming nanoparticle sized material components. A semiconductor oxide substrate includes nanoparticles of semiconductor oxide. A modifier is deposited onto the nanoparticles, and a source of metal ions are deposited in association with the semiconductor and the modifier, the modifier enabling electronic hole scavenging and chelation of the metal ions. The metal ions and modifier are illuminated to cause reduction of the metal ions to metal onto the semiconductor nanoparticles.

Semiconductor assisted metal deposition for nanolithography applications

DOEpatents

Rajh, Tijana; Meshkov, Natalia; Nedelijkovic, Jovan M.; Skubal, Laura R.; Tiede, David M.; Thurnauer, Marion

2002-01-01

An article of manufacture and method of forming nanoparticle sized material components. A semiconductor oxide substrate includes nanoparticles of semiconductor oxide. A modifier is deposited onto the nanoparticles, and a source of metal ions are deposited in association with the semiconductor and the modifier, the modifier enabling electronic hole scavenging and chelation of the metal ions. The metal ions and modifier are illuminated to cause reduction of the metal ions to metal onto the semiconductor nanoparticles.

Preparation of microcapsules containing double-component lubricant and self-lubricating performance of polymer composites

NASA Astrophysics Data System (ADS)

Li, Haiyan; Shi, Nanqi; Ji, Jing; Wang, Huaiyuan

2018-05-01

Double-component microcapsules containing lubricant oil and SiO2 nanoparticles were prepared by solvent evaporation method. The synthesized microcapsules have the regular spherical structure with the mean diameter of 105 μm and wall thickness of 15 μm. The synthesized microcapsules have excellent thermal stability, and the lubricant oil content was 71.4 wt%. Self-lubricating polymer composites were fabricated by incorporating double-component microcapsules into epoxy matrix. When the SiO2 nanoparticles content was 3 wt% relative to the lubricant oil, 10 wt% microcapsules brought 60.8% and 93.3% decrease for epoxy composites in the friction coefficient and specific wear rate, respectively. The synergetic effect between lubricant oil and SiO2 nanoparticles play a positive role in improving the triboligical properties of polymer composites.

Heterogeneous nucleation and growth of nanoparticles at environmental interfaces

DOE PAGES

Jun, Young -Shin; Kim, Doyoon; Neil, Chelsea W.

2016-08-11

Here, mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth’s crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolutionmore » of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.« less

Heterogeneous Nucleation and Growth of Nanoparticles at Environmental Interfaces.

PubMed

Jun, Young-Shin; Kim, Doyoon; Neil, Chelsea W

2016-09-20

Mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth's crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolution of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.

Defluoridation using biomimetically synthesized nano zirconium chitosan composite: kinetic and equilibrium studies.

PubMed

Prasad, Kumar Suranjit; Amin, Yesha; Selvaraj, Kaliaperumal

2014-07-15

The present study reports a novel approach for synthesis of Zr nanoparticles using aqueous extract of Aloe vera. Resulting nanoparticles were embedded into chitosan biopolymer and termed as CNZr composite. The composite was subjected to detailed adsorption studies for removal of fluoride from aqueous solution. The synthesized Zr nanoparticles showed UV-vis absorption peak at 420nm. TEM result showed the formation of polydispersed, nanoparticles ranging from 18nm to 42nm. SAED and XRD analysis suggested an fcc (face centered cubic) Zr crystallites. EDAX analysis suggested that Zr was an integral component of synthesized nanoparticles. FT-IR study indicated that functional group like NH, CO, CN and CC were involved in particle formation. The adsorption of fluoride on to CNZr composite worked well at pH 7.0, where ∼99% of fluoride was found to be adsorbed on adsorbent. Langmuir isotherm model best fitted the equilibrium data since it presented higher R(2) value than Freundlich model. In comparison to pseudo-first order kinetic model, the pseudo-second order model could explain adsorption kinetic behavior of F(-) onto CNZr composite satisfactorily with a good correlation coefficient. The present study revealed that CNZr composite may work as an effective tool for removal of fluoride from contaminated water. Copyright © 2014 Elsevier B.V. All rights reserved.

Enhancing the biofuel upgrade performance for Pd nanoparticles via increasing the support hydrophilicity of metal-organic frameworks.

PubMed

Sun, Qi; Chen, Meng; Aguila, Briana; Nguyen, Nicholas; Ma, Shengqian

2017-09-08

In this work, the influence of the hydrophilic/hydrophobic nature of metal-organic framework (MOF) materials on the catalytic performance of supported Pd nanoparticles for biofuel upgrade was studied. We show that the introduction of hydrophilic groups on a MOF can greatly enhance the performance of the resultant catalyst. Specifically, Pd nanoparticles supported on MIL-101-SO 3 Na with superhydrophilicity (Pd/MIL-101-SO 3 Na) far outperforms pristine MIL-101 and the benchmark catalyst Pd/C in the hydrodeoxygenation reaction of vanillin, a model component of pyrolysis oil derived from the lignin fraction. This is attributed to a favorable mode of adsorption of the highly water soluble reactants on the more hydrophilic support in the vicinity of the catalytically active Pd nanoparticles, thereby promoting their transformation.

A multi purpose source chamber at the PLEIADES beamline at SOLEIL for spectroscopic studies of isolated species: cold molecules, clusters, and nanoparticles.

PubMed

Lindblad, Andreas; Söderström, Johan; Nicolas, Christophe; Robert, Emmanuel; Miron, Catalin

2013-11-01

This paper describes the philosophy and design goals regarding the construction of a versatile sample environment: a source capable of producing beams of atoms, molecules, clusters, and nanoparticles in view of studying their interaction with short wavelength (vacuum ultraviolet and x-ray) synchrotron radiation. In the design, specific care has been taken of (a) the use standard components, (b) ensuring modularity, i.e., that swiftly switching between different experimental configurations was possible. To demonstrate the efficiency of the design, proof-of-principle experiments have been conducted by recording x-ray absorption and photoelectron spectra from isolated nanoparticles (SiO2) and free mixed clusters (Ar/Xe). The results from those experiments are showcased and briefly discussed.

Brownian rotational relaxation and power absorption in magnetite nanoparticles

NASA Astrophysics Data System (ADS)

Goya, G. F.; Fernandez-Pacheco, R.; Arruebo, M.; Cassinelli, N.; Ibarra, M. R.

2007-09-01

We present a study of the power absorption efficiency in several magnetite-based colloids, to asses their potential as magnetic inductive hyperthermia (MIH) agents. Relaxation times τ were measured through the imaginary susceptibility component χ″(T), and analyzed within Debye's theory of dipolar fluid. The results indicated Brownian rotational relaxation and allowed to calculate the hydrodynamic radius close to the values obtained from photon correlation. The study of the colloid performances as power absorbers showed no detectable increase of temperature for dextran-coated Fe 3O 4 nanoparticles, whereas a second Fe 3O 4-based dispersion of similar concentration could be heated up to 12 K after 30 min under similar experimental conditions. The different power absorption efficiencies are discussed in terms of the magnetic structure of the nanoparticles.

Evaluation of Unbound Engineered Nanoparticles from a Worker Exposure and Environmental Release Perspective

NASA Astrophysics Data System (ADS)

Bunker, K.; Casuccio, G.; Lersch, T.; Ogle, R.; Wahl, L.

2009-12-01

Nanotechnology and the use of unbound engineered nanoparticles (UNP) is a rapidly developing area of materials science. UNP are defined as engineered nanoparticles that are not contained within a matrix that would prevent the nanoparticles from being mobile and a potential source of exposure. At this time there are no regulatory environmental release limits or worker exposure limits for UNP. The Lawrence Berkeley National Laboratory (LBNL) has initiated a study to evaluate worker exposure and potential environmental release of UNP related to various research activities at LBNL. The study is being performed to help identify and manage potential health and safety hazards as well as environmental impacts related to UNP. A key component of the study is the characterization of starting (source) UNP materials to assist in the determination of worker exposure and environmental release. Analysis of the starting materials is being used to establish source signatures. The source signatures will then be used in the evaluation of worker exposure and environmental release. This presentation will provide an overview of the LBNL study with a focus on the methodologies being used to analyze the samples.

Magnetically encoded luminescent composite nanoparticles through layer-by-layer self-assembly.

PubMed

Song, Erqun; Han, Weiye; Xu, Hongyan; Jiang, Yunfei; Cheng, Dan; Song, Yang; Swihart, Mark T

2014-11-03

Sensitive and rapid detection of multiple analytes and the collection of components from complex samples are important in fields ranging from bioassays/chemical assays, clinical diagnosis, to environmental monitoring. A convenient strategy for creating magnetically encoded luminescent CdTe@SiO2 @n Fe3 O4 composite nanoparticles, by using a layer-by-layer self-assembly approach based on electrostatic interactions, is described. Silica-coated CdTe quantum dots (CdTe@SiO2 ) serve as core templates for the deposition of alternating layers of Fe3 O4 magnetic nanoparticles and poly(dimethyldiallyl ammonium chloride), to construct CdTe@SiO2 @n Fe3 O4 (n=1, 2, 3, …︁) composite nanoparticles with a defined number (n) of Fe3 O4 layers. Composite nanoparticles were characterized by zeta-potential analysis, fluorescence spectroscopy, vibrating sample magnetometry, and transmission electron microscopy, which showed that the CdTe@SiO2 @n Fe3 O4 composite nanoparticles exhibited excellent luminescence properties coupled with well-defined magnetic responses. To demonstrate the utility of these magnetically encoded nanoparticles for near-simultaneous detection and separation of multiple components from complex samples, three different fluorescently labeled IgG proteins, as model targets, were identified and collected from a mixture by using the CdTe@SiO2 @n Fe3 O4 nanoparticles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and Characterization of Pure Copper Nanostructures Using Wood Inherent Architecture as a Natural Template

NASA Astrophysics Data System (ADS)

Dong, Youming; Wang, Kaili; Tan, Yi; Wang, Qingchun; Li, Jianzhang; Mark, Hughes; Zhang, Shifeng

2018-04-01

The inherent sophisticated structure of wood inspires researchers to use it as a natural template for synthesizing functional nanoparticles. In this study, pure copper nanoparticles were synthesized using poplar wood as a natural inexpensive and renewable template. The crystal structure and morphologies of the copper nanoparticles were characterized by X-ray diffraction and field emission scanning electron microscopy. The optical properties, antibacterial properties, and stability of the hybrid wood materials were also tested. Due to the hierarchical and anisotropic structure and electron-rich components of wood, pure copper nanoparticles with high stability were synthesized with fcc structure and uniform sizes and then assembled into corncob-like copper deposits along the wood cell lumina. The products of nanoparticles depended strongly on the initial OH- concentration. With an increase in OH- concentration, Cu2O gradually decreased and Cu remained. Due to the restrictions inherent in wood structure, the derived Cu nanoparticles showed similar grain size in spite of increased Cu2+ concentration. This combination of Cu nanostructures and wood exhibited remarkable optical and antibacterial properties.

Particokinetics: computational analysis of the superparamagnetic iron oxide nanoparticles deposition process

PubMed Central

Cárdenas, Walter HZ; Mamani, Javier B; Sibov, Tatiana T; Caous, Cristofer A; Amaro, Edson; Gamarra, Lionel F

2012-01-01

Background Nanoparticles in suspension are often utilized for intracellular labeling and evaluation of toxicity in experiments conducted in vitro. The purpose of this study was to undertake a computational modeling analysis of the deposition kinetics of a magnetite nanoparticle agglomerate in cell culture medium. Methods Finite difference methods and the Crank–Nicolson algorithm were used to solve the equation of mass transport in order to analyze concentration profiles and dose deposition. Theoretical data were confirmed by experimental magnetic resonance imaging. Results Different behavior in the dose fraction deposited was found for magnetic nanoparticles up to 50 nm in diameter when compared with magnetic nanoparticles of a larger diameter. Small changes in the dispersion factor cause variations of up to 22% in the dose deposited. The experimental data confirmed the theoretical results. Conclusion These findings are important in planning for nanomaterial absorption, because they provide valuable information for efficient intracellular labeling and control toxicity. This model enables determination of the in vitro transport behavior of specific magnetic nanoparticles, which is also relevant to other models that use cellular components and particle absorption processes. PMID:22745539

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.

[Oxidative stress derived from airborne fine and ultrafine particles and the effects on brain-nervous system: part 1].

PubMed

Sagai, Masaru; Win-Shwe, Tin Tin

2015-01-01

Traffic-related air pollution is a major contributor to urban air pollution. Diesel exhaust (DE) is the most important component of near-road and urban air pollution and is commonly used as a surrogate model of air pollution in health effects studies. In particular, diesel exhaust particles (DEP) and the nanoparticles in DEP are considered hazardous components on health effects. It is widely known that exposure to DEP is associated with mortality due to respiratory and cardiovascular diseases. Recently, there has been accumulating evidence that DEP and the nanoparticles in DEP may be causes of neurodegenerative disorders. Here, we introduce the evidence suggesting their association with such disorders. First, we describe the chemical components and the translocation of DEP and nanoparticles to the brain, and then introduce the evidence and a mechanism by which reactive oxygen species (ROS) and any inflammatory mediators can be produced by DEP phagocytosis of macrophages, microglia and astrocyte cells in the brain. There are many lines of evidence showing that the neurodegenerative disorders are profoundly associated with enhanced oxidative and inflammatory events. Second, we describe a mechanism by which neurodegenerative diseases, such as stroke, Alzheimer's disease and Parkinson's disease, are induced via oxidative stress and inflammatory events.

Stimuli-Responsive Polymeric Nanoparticles.

PubMed

Liu, Xiaolin; Yang, Ying; Urban, Marek W

2017-07-01

There is increasing evidence that stimuli-responsive nanomaterials have become significantly critical components of modern materials design and technological developments. Recent advances in synthesis and fabrication of stimuli-responsive polymeric nanoparticles with built-in stimuli-responsive components (Part A) and surface modifications of functional nanoparticles that facilitate responsiveness (Part B) are outlined here. The synthesis and construction of stimuli-responsive spherical, core-shell, concentric, hollow, Janus, gibbous/inverse gibbous, and cocklebur morphologies are discussed in Part A, with the focus on shape, color, or size changes resulting from external stimuli. Although inorganic/metallic nanoparticles exhibit many useful properties, including thermal or electrical conductivity, catalytic activity, or magnetic properties, their assemblies and formation of higher order constructs are often enhanced by surface modifications. Section B focuses on selected surface reactions that lead to responsiveness achieved by decorating nanoparticles with stimuli-responsive polymers. Although grafting-to and grafting-from dominate these synthetic efforts, there are opportunities for developing novel synthetic approaches facilitating controllable recognition, signaling, or sequential responses. Many nanotechnologies utilize a combination of organic and inorganic phases to produce ceramic or metallic nanoparticles. One can envision the development of new properties by combining inorganic (metals, metal oxides) and organic (polymer) phases into one nanoparticle designated as "ceramers" (inorganics) and "metamers" (metallic). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Computer Optimization of Biodegradable Nanoparticles Fabricated by Dispersion Polymerization.

PubMed

Akala, Emmanuel O; Adesina, Simeon; Ogunwuyi, Oluwaseun

2015-12-22

Quality by design (QbD) in the pharmaceutical industry involves designing and developing drug formulations and manufacturing processes which ensure predefined drug product specifications. QbD helps to understand how process and formulation variables affect product characteristics and subsequent optimization of these variables vis-à-vis final specifications. Statistical design of experiments (DoE) identifies important parameters in a pharmaceutical dosage form design followed by optimizing the parameters with respect to certain specifications. DoE establishes in mathematical form the relationships between critical process parameters together with critical material attributes and critical quality attributes. We focused on the fabrication of biodegradable nanoparticles by dispersion polymerization. Aided by a statistical software, d-optimal mixture design was used to vary the components (crosslinker, initiator, stabilizer, and macromonomers) to obtain twenty nanoparticle formulations (PLLA-based nanoparticles) and thirty formulations (poly-ɛ-caprolactone-based nanoparticles). Scheffe polynomial models were generated to predict particle size (nm), zeta potential, and yield (%) as functions of the composition of the formulations. Simultaneous optimizations were carried out on the response variables. Solutions were returned from simultaneous optimization of the response variables for component combinations to (1) minimize nanoparticle size; (2) maximize the surface negative zeta potential; and (3) maximize percent yield to make the nanoparticle fabrication an economic proposition.

Orientation-dependent deformation mechanisms of bcc niobium nanoparticles

NASA Astrophysics Data System (ADS)

Bian, J. J.; Yang, L.; Niu, X. R.; Wang, G. F.

2018-07-01

Nanoparticles usually exhibit pronounced anisotropic properties, and a close insight into the atomic-scale deformation mechanisms is of great interest. In present study, atomic simulations are conducted to analyse the compression of bcc nanoparticles, and orientation-dependent features are addressed. It is revealed that surface morphology under indenter predominantly governs the initial elastic response. The loading curve follows the flat punch contact model in [1 1 0] compression, while it obeys the Hertzian contact model in [1 1 1] and [0 0 1] compressions. In plastic deformation regime, full dislocation gliding is dominated in [1 1 0] compression, while deformation twinning is prominent in [1 1 1] compression, and these two mechanisms coexist in [0 0 1] compression. Such deformation mechanisms are distinct from those in bulk crystals under nanoindentation and nanopillars under compression, and the major differences are also illuminated. Our results provide an atomic perspective on the mechanical behaviours of bcc nanoparticles and are helpful for the design of nanoparticle-based components and systems.

Lipid-Based Nanoparticles as Pharmaceutical Drug Carriers: From Concepts to Clinic

PubMed Central

Puri, Anu; Loomis, Kristin; Smith, Brandon; Lee, Jae-Ho; Yavlovich, Amichai; Heldman, Eli; Blumenthal, Robert

2010-01-01

In recent years, various nanotechnology platforms in the area of medical biology, including both diagnostics and therapy, have gained remarkable attention. Moreover, research and development of engineered multifunctional nanoparticles as pharmaceutical drug carriers have spurred exponential growth in applications to medicine in the last decade. Design principles of these nanoparticles, including nano-emulsions, dendrimers, nano-gold, liposomes, drug-carrier conjugates, antibody-drug complexes, and magnetic nanoparticles, are primarily based on unique assemblies of synthetic, natural, or biological components, including but not limited to synthetic polymers, metal ions, oils, and lipids as their building blocks. However, the potential success of these particles in the clinic relies on consideration of important parameters such as nanoparticle fabrication strategies, their physical properties, drug loading efficiencies, drug release potential, and, most importantly, minimum toxicity of the carrier itself. Among these, lipid-based nanoparticles bear the advantage of being the least toxic for in vivo applications, and significant progress has been made in the area of DNA/RNA and drug delivery using lipid-based nanoassemblies. In this review, we will primarily focus on the recent advances and updates on lipid-based nanoparticles for their projected applications in drug delivery. We begin with a review of current activities in the field of liposomes (the so-called honorary nanoparticles), and challenging issues of targeting and triggering will be discussed in detail. We will further describe nanoparticles derived from a novel class of amphipathic lipids called bolaamphiphiles with unique lipid assembly features that have been recently examined as drug/DNA delivery vehicles. Finally, an overview of an emerging novel class of particles (based on lipid components other than phospholipids), solid lipid nanoparticles and nanostructured lipid carriers will be presented. We conclude with a few examples of clinically successful formulations of currently available lipid-based nanoparticles. PMID:20402623

Design challenges in nanoparticle-based platforms: Implications for targeted drug delivery systems

NASA Astrophysics Data System (ADS)

Mullen, Douglas Gurnett

Characterization and control of heterogeneous distributions of nanoparticle-ligand components are major design challenges for nanoparticle-based platforms. This dissertation begins with an examination of poly(amidoamine) (PAMAM) dendrimer-based targeted delivery platform. A folic acid targeted modular platform was developed to target human epithelial cancer cells. Although active targeting was observed in vitro, active targeting was not found in vivo using a mouse tumor model. A major flaw of this platform design was that it did not provide for characterization or control of the component distribution. Motivated by the problems experienced with the modular design, the actual composition of nanoparticle-ligand distributions were examined using a model dendrimer-ligand system. High Pressure Liquid Chromatography (HPLC) resolved the distribution of components in samples with mean ligand/dendrimer ratios ranging from 0.4 to 13. A peak fitting analysis enabled the quantification of the component distribution. Quantified distributions were found to be significantly more heterogeneous than commonly expected and standard analytical parameters, namely the mean ligand/nanoparticle ratio, failed to adequately represent the component heterogeneity. The distribution of components was also found to be sensitive to particle modifications that preceded the ligand conjugation. With the knowledge gained from this detailed distribution analysis, a new platform design was developed to provide a system with dramatically improved control over the number of components and with improved batch reproducibility. Using semi-preparative HPLC, individual dendrimer-ligand components were isolated. The isolated dendrimer with precise numbers of ligands were characterized by NMR and analytical HPLC. In total, nine different dendrimer-ligand components were obtained with degrees of purity ≥80%. This system has the potential to serve as a platform to which a precise number of functional molecules can be attached and has the potential to dramatically improve platform efficacy. An additional investigation of reproducibility challenges for current dendrimer-based platform designs is also described. The mass transport quality during the partial acetylation reaction of the dendrimer was found to have a major impact on subsequent dendrimer-ligand distributions that cannot be detected by standard analytical techniques. Consequently, this reaction should be eliminated from the platform design. Finally, optimized protocols for purification and characterization of PAMAM dendrimer were detailed.

Use of Soybean Lecithin in Shape Controlled Synthesis of Gold Nanoparticles

NASA Astrophysics Data System (ADS)

Ayres, Benjamin Robert

The work presented in this dissertation is a composite of experiments in the growth of gold nanoparticles with specific optical properties of interest. The goal is to synthesize these gold nanoparticles using soybean extract for not only shape control, but for propensity as a biocompatible delivery system. The optical properties of these nanoparticles has found great application in coloring glass during the Roman empire and, over the centuries, has grown into its own research field in applications of nanoparticulate materials. Many of the current functions include use in biological systems as biosensors and therapeutic applications, thus making biocompatibility a necessity. Current use of cetyltrimethylammonium bromide leads to rod-shaped gold nanoparticles, however, the stability of these gold nanoparticles does not endure for extended periods of time in aqueous media. In my research, two important components were found to be necessary for stable, anisotropic growth of gold nanoparticles. In the first experiments, it was found that bromide played a key role in shape control. Bromide exchange on the gold atoms led to specific packing of the growing crystals, allowing for two-dimensional growth of gold nanoparticles. It was also discerned that soybean lecithin contained ligands that blocked specific gold facets leading to prismatic gold nanoparticle growth. These gold nanoprisms give a near infrared plasmon absorption similar to that of rod-shaped gold nanoparticles. These gold nanoprisms are discovered to be extremely stable in aqueous media and remain soluble for extended periods of time, far longer than that of gold nanoparticles grown using cetyltrimethylammonium bromide. Since soy lecithin has a plethora of compounds present, it became necessary to discover which compound was responsible for the shape control of the gold nanoprisms in order to optimize the synthesis and allow for a maximum yield of the gold nanoprisms. Many of these components were identified by high performance liquid chromatography and liquid chromatography-mass spectrometry. However, re-spike of these components into growth solutions did not enhance the growth of gold nanoprisms. Upon separating the shapes of the gold nanoparticles using gel electrophoresis, addition of KCN to the separated gold nanoparticles allowed us to extract the culpable ligands for shape control. Analysis of these ligands by mass spectrometry elucidated the identity of PA and upon re-spike of the PA into a growth solution of PC95, the growth of a near-infrared plasmon absorption was seen. The stability of these gold nanoparticles was tested with and without the addition of decane thiol and it was concluded that addition of the thiol allowed for improved stability of the gold nanoparticles towards cyanide. It was determined that at a concentration of 2 μM decanethiol, spherical gold nanoparticles remained stable to cyanide at the expense of the prismatic gold nanoparticles. However, at 5 μM decanethiol, both spherical and prismatic gold nanoparticles retained stability to cyanide in aqueous conditions.

HPMA-based block copolymers promote differential drug delivery kinetics for hydrophobic and amphiphilic molecules.

PubMed

Tomcin, Stephanie; Kelsch, Annette; Staff, Roland H; Landfester, Katharina; Zentel, Rudolf; Mailänder, Volker

2016-04-15

We describe a method how polymeric nanoparticles stabilized with (2-hydroxypropyl)methacrylamide (HPMA)-based block copolymers are used as drug delivery systems for a fast release of hydrophobic and a controlled release of an amphiphilic molecule. The versatile method of the miniemulsion solvent-evaporation technique was used to prepare polystyrene (PS) as well as poly-d/l-lactide (PDLLA) nanoparticles. Covalently bound or physically adsorbed fluorescent dyes labeled the particles' core and their block copolymer corona. Confocal laser scanning microscopy (CLSM) in combination with flow cytometry measurements were applied to demonstrate the burst release of a fluorescent hydrophobic drug model without the necessity of nanoparticle uptake. In addition, CLSM studies and quantitative calculations using the image processing program Volocity® show the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake. Our findings offer the possibility to combine the advantages of a fast release for hydrophobic and a controlled release for an amphiphilic molecule therefore pointing to the possibility to a 'multi-step and multi-site' targeting by one nanocarrier. We describe thoroughly how different components of a nanocarrier end up in cells. This enables different cargos of a nanocarrier having a consecutive release and delivery of distinct components. Most interestingly we demonstrate individual kinetics of distinct components of such a system: first the release of a fluorescent hydrophobic drug model at contact with the cell membrane without the necessity of nanoparticle uptake. Secondly, the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake occurs. This offers the possibility to combine the advantages of a fast release for a hydrophobic substance at the time of interaction of the nanoparticle with the cell surface and a controlled release for an amphiphilic molecule later on therefore pointing to the possibility to a 'multi-step and multisite' targeting by one nanocarrier. We therefore feel that this could be used for many cellular systems where the combined and orchestrated delivery of components is prerequisite in order to obtain the highest efficiency. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Visualization of MMP-2 Activity Using Dual-Probe Nanoparticles to Detect Potential Metastatic Cancer Cells

PubMed Central

Kim, Sung Hoon; Lee, Hyun; Kim, Bohee; Kim, Yoon Suk; Key, Jaehong

2018-01-01

Matrix metalloproteinases (MMPs) are a family of zinc-dependent enzymes capable of degrading extracellular matrix components. Previous studies have shown that the upregulation of MMP-2 is closely related to metastatic cancers. While Western blotting, zymography, and Enzyme-Linked Immunosorbent Assays (ELISA) can be used to measure the amount of MMP-2 activity, it is not possible to visualize the dynamic MMP-2 activities of cancer cells using these techniques. In this study, MMP-2-activated poly(lactic-co-glycolic acid) with polyethylenimine (MMP-2-PLGA-PEI) nanoparticles were developed to visualize time-dependent MMP-2 activities. The MMP-2-PLGA-PEI nanoparticles contain MMP-2-activated probes that were detectable via fluorescence microscopy only in the presence of MMP-2 activity, while the Rhodamine-based probes in the nanoparticles were used to continuously visualize the location of the nanoparticles. This approach allowed us to visualize MMP-2 activities in cancer cells and their microenvironment. Our results showed that the MMP-2-PLGA-PEI nanoparticles were able to distinguish between MMP-2-positive (HaCat) and MMP-2-negative (MCF-7) cells. While the MMP-2-PLGA-PEI nanoparticles gave fluorescent signals recovered by active recombinant MMP-2, there was no signal recovery in the presence of an MMP-2 inhibitor. In conclusion, MMP-2-PLGA-PEI nanoparticles are an effective tool to visualize dynamic MMP-2 activities of potential metastatic cancer cells. PMID:29466303

Photochemically synthesized heparin-based silver nanoparticles: an antimicrobial activity study

NASA Astrophysics Data System (ADS)

Rodriguez-Torres, Maria del Pilar; Acosta-Torres, Laura Susana; Díaz-Torres, Luis Armando

2017-08-01

The antimicrobial activity of silver nanoparticles has been extensively studied in the last years. Such nanoparticles constitute a potential and promising approach for the development of new antimicrobial systems especially due to the fact that several microorganisms are developing resistance to some already existing antimicrobial agents, therefore making antibacterial and antimicrobial studies on alternative materials necessary to overcome this issue. Silver nanoparticle concentration and size are determining factors on the antimicrobial activity of these nano systems. Heparin is a polysaccharide that belongs to the glycosaminoglycans (GAGs) family, molecules formed by a base disaccharide whose components are joined by a glycosidic linkage that is a repeating unit along their structure. It is highly sulfated making it a negatively charged material that is also widely used as an anticoagulant in Medicine because its biocompatibility besides it is also produced within the human body, specifically in the mast cells. Heparin alone possesses antimicrobial activity although it has not been studied very much in detail, it only has been demonstrated that it inhibits E. coli, P. aeruginosa, S. aureus and S. epidermidis, so taking this into account, this study is dedicated to assess UV photochemically-synthesized (λ=254 nm) heparin-based silver nanoparticles antimicrobial activity using the agar disk diffusion method complemented by the broth microdilution method to estimate de minimum inhibitory concentration (MIC), that is the lowest concentration at which an antimicrobial will inhibit visible growth of a microorganism. The strains used were the ones aforementioned to assess the antimicrobial activity degree these heparinbased nanoparticles exhibit.

Drug release studies from lipid nanoparticles in physiological media by a new DSC method.

PubMed

Roese, Elin; Bunjes, Heike

2017-06-28

Lipid nanoparticles are an interesting parenteral delivery system for poorly water-soluble drugs. In order to approach physiological conditions when conducting release studies from such systems the release media should preferentially contain lipophilic acceptor compartments such as lipoproteins or other colloidal lipophilic components. In practice, drug release studies under such close to physiological conditions may be complicated by the small size of lipid nanoparticles, which is in the same range as that of the potential acceptor particles. This study describes a novel differential scanning calorimetry (DSC) method for drug release measurements which works without separation of donor and acceptor particles. The technique is based on measuring the crystallization temperature of trimyristin nanoparticles by DSC. The crystallization temperature of the nanoparticles decreases proportionally with the amount of active ingredient incorporated and thus increases as a result of drug release. Liquid trimyristin nanoparticles loaded with fenofibrate, orlistat, tocopherol acetate and ubidecarenone were studied in three different release media with increasing complexity and comparability to physiological conditions: a rapeseed oil nanoemulsion, porcine serum and porcine blood. Using the new method, a correlation between release behavior and drug lipophilicity was observed: the higher the logP value of the drug, the slower the release. The extent of drug release was influenced by partition equilibrium as indicated by increased drug release in the rapeseed oil nanoemulsion compared to porcine serum and blood. Copyright © 2017 Elsevier B.V. All rights reserved.

Remote activation of a microactuator using a photo-responsive nanoparticle-polymer composite

NASA Astrophysics Data System (ADS)

Zeberoff, Anthony

Stimulus response materials are a class of novel materials that are currently being explored in various technologies, including biomedical devices and components, food packaging, fabrics, energy harvesting and conversion, and other elementary components such as sensors and actuators. Hybrid organic-inorganic materials such as nanoparticle-polymer composites are attractive candidates as their properties can be significantly tuned for particular applications where selectivity and localized responses are critical factors. In this work we developed and optimized a photo-responsive microactuator that can operate selectively to a specific wavelength of light. The photo-responsive microactuator is comprised of monodispersed microspheres that contain gold nanoparticles. Upon irradiation, these microspheres transduce optical energy to thermal energy, driving a localized phase change in the matrix in which they are embedded. Our remotely powered microactuator can be further realized in applications where decoupling the physical connection of the energy/control source from the actuating component is necessary.

Unveiling the chemistry behind the green synthesis of metal nanoparticles.

PubMed

Santos, Sónia A O; Pinto, Ricardo J B; Rocha, Sílvia M; Marques, Paula A A P; Pascoal Neto, Carlos; Silvestre, Armando J D; Freire, Carmen S R

2014-09-01

Nanobiotechnology has emerged as a fundamental domain in modern science, and metallic nanoparticles (NPs) are one of the largest classes of NPs studied because of their wide spectrum of possible applications in several fields. The use of plant extracts as reducing and stabilizing agents in their synthesis is an interesting and reliable alternative to conventional methodologies. However, the role of the different components of such extracts in the reduction/stabilization of metal ions has not yet been understood clearly. Here we studied the behavior of the main components of a Eucalyptus globulus Labill. bark aqueous extract during metal-ion reduction followed by advanced chromatographic techniques, which allowed us to establish their specific role in the process. The obtained results showed that phenolic compounds, particularly galloyl derivatives, are mainly responsible for the metal-ion reduction, whereas sugars are essentially involved in the stabilization of the NPs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Individual and collective modes of surface magnetoplasmon in thiolate-protected silver nanoparticles studied by MCD spectroscopy

NASA Astrophysics Data System (ADS)

Yao, Hiroshi; Shiratsu, Taisuke

2016-05-01

Large magneto-optical (MO) responses at the energy of localized surface plasmon resonance (LSPR), namely, surface magnetoplasmons, are demonstrated for the first time in thiolate-protected silver nanoparticles with magnetic circular dichroism (MCD) spectroscopy. The samples examined are decanethiol (DT)-, azobenzenethiol (ABT)-, and ABT/DT mixed-monolayer-protected Ag nanoparticles. ABT-protected Ag nanoparticles are somewhat aggregated and thus exhibit a broad, collective mode of plasmonic absorption, whereas other samples with highly-dispersed nanoparticles show an individual mode of LSPR absorption. In all Ag nanoparticles, a derivative-like MCD signal is observed under an applied magnetic field of 1.6 T, which can be explained in terms of two circular modes of magnetoplasmon caused by the increase (or decrease) in the Lorentz force imparted on the free electrons that oscillate in the left (or right) circular orbits in the nanosphere. For the Ag nanoparticles exhibiting an individual LSPR mode, in particular, simultaneous deconvolution analysis of UV-vis absorption and MCD spectra reveal that (i) the amplitude of the magnetoplasmonic component with lower frequency (ω-), resulting from the reduction in the confinement strength of collective electrons by the Lorentz force, is stronger than that with a higher frequency (ω+) (ii) the accurate shift or cyclotron frequency between two magnetoplasmonic modes (ωc = ω+ - ω-) is size-dependent, and presents a very large value with implications for the apparent enhancement of the local magnetic-field in the Ag nanoparticles. These results strongly suggest that the Ag-thiolate layer or Ag-S bonding on the nanoparticle surface plays a significant role in the MO enhancement.Large magneto-optical (MO) responses at the energy of localized surface plasmon resonance (LSPR), namely, surface magnetoplasmons, are demonstrated for the first time in thiolate-protected silver nanoparticles with magnetic circular dichroism (MCD) spectroscopy. The samples examined are decanethiol (DT)-, azobenzenethiol (ABT)-, and ABT/DT mixed-monolayer-protected Ag nanoparticles. ABT-protected Ag nanoparticles are somewhat aggregated and thus exhibit a broad, collective mode of plasmonic absorption, whereas other samples with highly-dispersed nanoparticles show an individual mode of LSPR absorption. In all Ag nanoparticles, a derivative-like MCD signal is observed under an applied magnetic field of 1.6 T, which can be explained in terms of two circular modes of magnetoplasmon caused by the increase (or decrease) in the Lorentz force imparted on the free electrons that oscillate in the left (or right) circular orbits in the nanosphere. For the Ag nanoparticles exhibiting an individual LSPR mode, in particular, simultaneous deconvolution analysis of UV-vis absorption and MCD spectra reveal that (i) the amplitude of the magnetoplasmonic component with lower frequency (ω-), resulting from the reduction in the confinement strength of collective electrons by the Lorentz force, is stronger than that with a higher frequency (ω+) (ii) the accurate shift or cyclotron frequency between two magnetoplasmonic modes (ωc = ω+ - ω-) is size-dependent, and presents a very large value with implications for the apparent enhancement of the local magnetic-field in the Ag nanoparticles. These results strongly suggest that the Ag-thiolate layer or Ag-S bonding on the nanoparticle surface plays a significant role in the MO enhancement. Electronic supplementary information (ESI) available: EDX spectroscopic analysis of various Ag nanoparticle samples; MCD signals normalized to absorbance for the Ag(DT)L and Ag(DT)S samples; deconvolution of UV-vis absorption and MCD spectra using three Lorentzian components; IR spectral changes upon photoisomerization; thermal cis-to-trans relaxation of azobenzene in the Ag(ABT) sample; UV-vis absorption spectra of Ag nanoparticle samples in the presence/absence of a magnetic field of 1.6 T. See DOI: 10.1039/c6nr00631k

Light-induced thermodiffusion in two-component media

NASA Astrophysics Data System (ADS)

Ivanov, V.; Ivanova, G.; Okishev, K.; Khe, V.

2017-01-01

We have theoretically studied the optical transmittance response of thin cell with liquid containing absorbing nanoparticles in a Gaussian beam field. The transmittance spatial changing is caused by thermal diffusion phenomenon (Soret effect) which produces the variations of concentration of absorbing nanoparticles. The thickness of optical cell (including windows) is significantly less than the size of the beam. As a result, an exact analytical expression for the one dimensional thermal task is derived, taking into account the Soret feedback that leads to the temperature rising on the axis of a Gaussian beam. We have experimentally studied this phenomenon in carbon nanosuspension.

Quantum Dot Distribution in the Olfactory Epithelium After Nasal Delivery

NASA Astrophysics Data System (ADS)

Garzotto, D.; De Marchis, S.

2010-10-01

Nanoparticles are used in a wide range of human applications from industrial to bio-medical fields. However, the unique characteristics of nanoparticles, such as the small size, large surface area per mass and high reactivity raises great concern on the adverse effects of these particles on ecological systems and human health. There are several pioneer studies reporting translocation of inhaled particulates to the brain through a potential neuronal uptake mediated by the olfactory nerve (1, 2, 3). However, no direct evidences have been presented up to now on the pathway followed by the nanoparticles from the nose to the brain. In addition to a neuronal pathway, nanoparticles could gain access to the central nervous system through extracellular pathways (perineuronal, perivascular and cerebrospinal fluid paths). In the present study we investigate the localization of intranasally delivered fluorescent nanoparticles in the olfactory epithelium. To this purpose we used quantum dots (QDs), a model of innovative fluorescent semiconductor nanocrystals commonly used in cell and animal biology (4). Intranasal treatments with QDs were performed acutely on adult CD1 mice. The olfactory epithelium was collected and analysed by confocal microscopy at different survival time after treatment. Data obtained indicate that the neuronal components of the olfactory epithelium are not preferentially involved in QDs uptake, thus suggesting nanoparticles can cross the olfactory epithelium through extracellular pathways.

Heuristic rule for binary superlattice coassembly: mixed plastic mesophases of hard polyhedral nanoparticles.

PubMed

Khadilkar, Mihir R; Escobedo, Fernando A

2014-10-17

Sought-after ordered structures of mixtures of hard anisotropic nanoparticles can often be thermodynamically unfavorable due to the components' geometric incompatibility to densely pack into regular lattices. A simple compatibilization rule is identified wherein the particle sizes are chosen such that the order-disorder transition pressures of the pure components match (and the entropies of the ordered phases are similar). Using this rule with representative polyhedra from the truncated-cube family that form pure-component plastic crystals, Monte Carlo simulations show the formation of plastic-solid solutions for all compositions and for a wide range of volume fractions.

Antioxidant and anti-inflammatory activities of silver nanoparticles biosynthesized from aqueous leaves extracts of four Terminalia species

NASA Astrophysics Data System (ADS)

El-Rafie, Hanaa Mohamed; Abdel-Aziz Hamed, Manal

2014-09-01

The environmentally friendly synthesis of nanoparticles process is a revolutionary step in the field of nanotechnology. In recent years plant mediated biological synthesis of nanoparticles has been gaining importance due to its simplicity and eco-friendliness. In this study, a simple and an efficient eco-friendly approach for the biosynthesis of stable, monodisperse silver nanoparticles using aqueous extracts of four Terminalia species, namely, Terminalia catappa, Terminalia mellueri, Terminalia bentazoe and Terminalia bellerica were described. The silver nanoparticles were characterized in terms of synthesis, capping functionalities (polysaccharides, phenolics and flavonoidal compounds) and microscopic evaluation by UV-visible spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. The results showed a simple and feasible approach for obtaining stable aqueous monodispersive silver nanoparticles. Furthermore, biological activity of the biosynthesized silver nanoparticles was examined. Concerning this, dose-dependent antioxidant activity of silver nanoparticles imparted by the plant phenolic and flavonoidal components was evaluated using in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and found to be comparable to standard ascorbic acid. The same holds true for the anti-inflammatory activity where Terminalia catappa and Terminalia mellueri have a high-test inhibition percentage better than that of ascorbic acid in the carrageenan induced hind paw edema. The results also revealed that the aqueous extract of Terminallia catapa and its silver nanoparticles recorded the most potent in vivo antioxidant effect.

Nanoparticle-Hydrogel Composites: Concept, Design, and Applications of These Promising, Multi-Functional Materials.

PubMed

Thoniyot, Praveen; Tan, Mein Jin; Karim, Anis Abdul; Young, David James; Loh, Xian Jun

2015-02-01

New technologies rely on the development of new materials, and these may simply be the innovative combination of known components. The structural combination of a polymer hydrogel network with a nanoparticle (metals, non-metals, metal oxides, and polymeric moieties) holds the promise of providing superior functionality to the composite material with applications in diverse fields, including catalysis, electronics, bio-sensing, drug delivery, nano-medicine, and environmental remediation. This mixing may result in a synergistic property enhancement of each component: for example, the mechanical strength of the hydrogel and concomitantly decrease aggregation of the nanoparticles. These mutual benefits and the associated potential applications have seen a surge of interest in the past decade from multi-disciplinary research groups. Recent advances in nanoparticle-hydrogel composites are herein reviewed with a focus on their synthesis, design, potential applications, and the inherent challenges accompanying these exciting materials.

Terminal Supraparticle Assemblies from Similarly Charged Protein Molecules and Nanoparticles

PubMed Central

Park, Jai Il; Nguyen, Trung Dac; de Queirós Silveira, Gleiciani; Bahng, Joong Hwan; Srivastava, Sudhanshu; Sun, Kai; Zhao, Gongpu; Zhang, Peijun; Glotzer, Sharon C.; Kotov, Nicholas A.

2015-01-01

Self-assembly of proteins and inorganic nanoparticles into terminal assemblies makes possible a large family of uniformly sized hybrid colloids. These particles can be compared in terms of utility, versatility and multifunctionality to other known types of terminal assemblies. They are simple to make and offer theoretical tools for designing their structure and function. To demonstrate such assemblies, we combine cadmium telluride nanoparticles with cytochrome C protein and observe spontaneous formation of spherical supraparticles with a narrow size distribution. Such self-limiting behaviour originates from the competition between electrostatic repulsion and non-covalent attractive interactions. Experimental variation of supraparticle diameters for several assembly conditions matches predictions obtained in simulations. Similar to micelles, supraparticles can incorporate other biological components as exemplified by incorporation of nitrate reductase. Tight packing of nanoscale components enables effective charge and exciton transport in supraparticles as demonstrated by enzymatic nitrate reduction initiated by light absorption in the nanoparticle. PMID:24845400

Effects of nanoparticles on the compatibility of PEO-PMMA block copolymers.

PubMed

Mu, Dan; Li, Jian-Quan; Li, Wei-Dong; Wang, Song

2011-12-01

The compatibility of six kinds of designed poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA) copolymers was studied at 270, 298 and 400 K via mesoscopic modeling. The values of the order parameters depended on both the structures of the block copolymers and the simulation temperature, while the values of the order parameters of the long chains were higher than those of the short ones; temperature had a more obvious effect on long chains than on the short ones. Plain copolymers doped with poly(ethylene oxide) (PEO) or poly(methyl methacrylate) (PMMA) homopolymer showed different order parameter values. When a triblock copolymer had the same component at both ends and was doped with one of its component polymers as a homopolymer (such as A5B6A5 doped with B6 or A5 homopolymer), the value of its order parameter depended on the simulation temperature. The highest order parameter values were observed for A5B6A5 doped with B6 at 400 K and for A5B6A5 doped with A5 at 270 K. A study of copolymers doped with nanoparticles showed that the mesoscopic phase was influenced by not only the properties of the nanoparticles, such as the size and density, but also the compositions of the copolymers. Increasing the size of the nanoparticles used as a dopant had the most significant effect on the phase morphologies of the copolymers.

A study of ferromagnetic signals in SrTiO{sub 3} nanoparticles

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

Kovacs, P.; Des Roches, B.; Crandles, D. A.

It has been suggested that ferromagnetism may be a universal feature of nanoparticles related to particle size. We study this claim for the case of commercially produced SrTiO{sub 3} nanoparticles purchased from Alfa-Aesar. Both loosely-packed nanoparticle samples and pellets formed using uniaxial pressure were studied. Both loose and pressed samples were annealed in either air or in vacuum of 5×10{sup −6} Torr at 600, 800 and 1000°C. Then x-ray diffraction and SQUID measurements were made on the resulting samples. It was found that annealed loose powder samples always had a linear diamagnetic magnetization versus field response, while their pressed pelletmore » counterparts exhibit a ferromagnetic hysteresis component in addition to the linear diamagnetic signal. Williamson-Hall analysis reveals that the particle size in pressed pellet samples increases with annealing temperature but does not change significantly in loose powder samples. The main conclusion is that the act of pressing pellets in a die introduces a spurious ferromagnetic signal into SQUID measurements.« less

Engineered Hybrid Nanoparticles for On-Demand Diagnostics and Therapeutics.

PubMed

Nguyen, Kim Truc; Zhao, Yanli

2015-12-15

Together with the simultaneous development of nanomaterials and molecular biology, the bionano interface brings about various applications of hybrid nanoparticles in nanomedicine. The hybrid nanoparticles not only present properties of the individual components but also show synergistic effects for specialized applications. Thus, the development of advanced hybrid nanoparticles for targeted and on-demand diagnostics and therapeutics of diseases has rapidly become a hot research topic in nanomedicine. The research focus is to fabricate novel classes of programmable hybrid nanoparticles that are precisely engineered to maximize drug concentrations in diseased cells, leading to enhanced efficacy and reduced side effects of chemotherapy for the disease treatment. In particular, the hybrid nanoparticle platforms can simultaneously target diseased cells, enable the location to be imaged by optical methods, and release therapeutic drugs to the diseased cells by command. This Account specially discusses the rational fabrication of integrated hybrid nanoparticles and their applications in diagnostics and therapeutics. For diagnostics applications, hybrid nanoparticles can be utilized as imaging agents that enable detailed visualization at the molecular level. By the use of suitable targeting ligands incorporated on the nanoparticles, targeted optical imaging may be feasible with improved performance. Novel imaging techniques such as multiphoton excitation and photoacoustic imaging using near-infrared light have been developed using the intrinsic properties of particular nanoparticles. The use of longer-wavelength excitation sources allows deeper penetration into the human body for disease diagnostics and at the same time reduces the adverse effects on normal tissues. Furthermore, multimodal imaging techniques have been achieved by combining several types of components in nanoparticles, offering higher accuracy and better spatial views, with the aim of detecting life-threatening diseases before symptoms appear. For therapeutics applications, various nanoparticle-based treatment methods such as photodynamic therapy, drug delivery, and gene delivery have been developed. The intrinsic ability of organic nanoparticles to generate reactive oxygen species has been utilized for photodynamic therapy, and mesoporous silica nanoparticles have been widely used for drug loading and controlled delivery. Herein, the development of controlled-release systems that can specifically deliver drug molecules to target cells and release then upon triggering is highlighted. By control of the release of loaded drug molecules at precise sites (e.g., cancer cells or malignant tumors), side effects of the drugs are minimized. This approach provides better control and higher efficacy of drugs in the human body. Future personalized medicine is also feasible through gene delivery methods. Specific DNA/RNA-carrying nanoparticles are able to deliver them to target cells to obtain desired properties. This development may create an evolution in current medicine, leading to more personalized healthcare systems that can reduce the population screening process and also the duration of drug evaluation. Furthermore, nanoparticles can be incorporated with various components that can be used for simultaneous diagnostics and therapeutics. These multifunctional theranostic nanoparticles enable real-time monitoring of treatment process for more efficient therapy.

Mean square hydrogen fluctuations in chitosan/lecithin nanoparticles from elastic neutron scattering experiments

NASA Astrophysics Data System (ADS)

Sonvico, Fabio; Teresa Di Bari, Maria; Bove, Livia; Deriu, Antonio; Cavatorta, Fabrizio; Albanese, Gianfranco

2006-11-01

Recently, we have started a systematic study of the structure and dynamics of nano- and microparticles of interest as highly biocompatible drug carriers. For these particles, that are composed of polymeric and lipid material, a detailed understanding of the particle-solvent interactions is of key importance in order to tailor their characteristics for delivering drugs with specific chemical properties. Here we report results of elastic neutron scattering (ENS) investigations on lecithin/chitosan nanoparticles. They were first prepared by autoassembling the two components in aqueous solution; the samples were then freeze-dried and re-hydrated in a D 2O atmosphere. The experiments were performed in the temperature range of 20-50 K using the backscattering spectrometer IN13 at ILL (Grenoble, France). The comparison of samples in the dry state with similar ones at an hydration level of about 0.3-0.4 (g D 2O/g hydrated sample), indicates that the presence of an outer chitosan ‘‘coating’’ reduces the mean square fluctuations of the hydrogens in the lipid component, leading thus to a stiffer nanoparticle structure.

Polymeric nanoparticles: A study on the preparation variables and characterization methods.

PubMed

Crucho, Carina I C; Barros, Maria Teresa

2017-11-01

Since the emergence of Nanotechnology in the past decades, the development and design of nanomaterials has become an important field of research. An emerging component in this field is nanomedicine, wherein nanoscale materials are being developed for use as imaging agents or for drug delivery applications. Much work is currently focused in the preparation of well-defined nanomaterials in terms of size and shape. These factors play a significantly role in the nanomaterial behavior in vivo. In this context, this review focuses on the toolbox of available methods for the preparation of polymeric nanoparticles. We highlight some recent examples from the literature that demonstrate the influence of the preparation method on the physicochemical characteristics of the nanoparticles. Additionally, in the second part, the characterization methods for this type of nanoparticles are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

A multi purpose source chamber at the PLEIADES beamline at SOLEIL for spectroscopic studies of isolated species: Cold molecules, clusters, and nanoparticles

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

Lindblad, Andreas; Söderström, Johan; Nicolas, Christophe

2013-11-15

This paper describes the philosophy and design goals regarding the construction of a versatile sample environment: a source capable of producing beams of atoms, molecules, clusters, and nanoparticles in view of studying their interaction with short wavelength (vacuum ultraviolet and x-ray) synchrotron radiation. In the design, specific care has been taken of (a) the use standard components, (b) ensuring modularity, i.e., that swiftly switching between different experimental configurations was possible. To demonstrate the efficiency of the design, proof-of-principle experiments have been conducted by recording x-ray absorption and photoelectron spectra from isolated nanoparticles (SiO{sub 2}) and free mixed clusters (Ar/Xe). Themore » results from those experiments are showcased and briefly discussed.« less

Chitosan nanoparticles from marine squid protect liver cells against N-diethylnitrosoamine-induced hepatocellular carcinoma.

PubMed

Subhapradha, Namasivayam; Shanmugam, Vairamani; Shanmugam, Annaian

2017-09-01

Rationale of this study was framed to investigate the protective effect and anti-cancer property of nanoparticles based on chitosan isolated from squid, Sepioteuthis lessoniana, on hepatic cells in N-Nitrosodiethylamine-induced hepatocellular carcinoma in rats. The results conferred that the chitosan nanoparticle supplementation had a protective effect on liver cells by reducing the levels of marker enzymes and bilirubin and thus increasing the albumin levels. The level of reduced glutathione, ascorbic acid and α-tocopherol significantly increased in both post- and pre-treatment with chitosan nanoparticles. The levels of antioxidant enzymes were enhanced and lipid peroxidation products were diminished while treating nitrosodiethylamine-induced hepatocellular carcinoma with chitosan nanoparticles. Supplementation of chitosan nanoparticles had potent anti-hyperlipidemic property that was evidenced by monitoring the serum lipid levels and its components. Animals pre-treated with chitosan nanoparticles along with nitrosodiethylamine showed a significant reduction in the total cholesterol and triglycerides levels with increase in the levels of phospholipids and free fatty acids. Chitosan nanoparticles treated rats showed significant increment in high-density lipoprotein cholesterol and reduction in low-density lipoprotein and very low-density lipoprotein cholesterol when compared with levels in nitrosodiethylamine-induced hepatocellular carcinoma. Nitrosodiethylamine-induced carcinoma changes on circulation and hepatic antioxidant defense mechanism were regulated by chitosan nanoparticles, concluding that the chitosan nanoparticles have a potent protective effect on liver cells which might be due to its robust antioxidant and anti-lipidemic property. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Biological Potency Of Carbonaceous Nanoparticles Is Associated With The State Of Oxidation Of Surface Carbon Atoms

EPA Science Inventory

Epidemiological studies have shown that exposure to ambient particulate matter (PM) is associated with excess morbidity and mortality. An important component of PM consists of inorganic and organic compounds adsorbed onto a carbonaceous particle core. Toxicological studies indica...

A cerium oxide nanoparticle-based device for the detection of chronic inflammation via optical and magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Kaittanis, Charalambos; Santra, Santimukul; Asati, Atul; Perez, J. Manuel

2012-03-01

Monitoring of microenvironmental parameters is critical in healthcare and disease management. Harnessing the antioxidant activity of nanoceria and the imaging capabilities of iron oxide nanoparticles in a device setup, we were able to image changes in the device's aqueous milieu. The device was able to convey and process changes in the microenvironment's pH and reactive oxygen species' concentration, distinguishing physiological from abnormal levels. As a result under physiological and transient inflammatory conditions, the device's fluorescence and magnetic resonance signals, emanating from multimodal iron oxide nanoparticles, were similar. However, under chronic inflammatory conditions that are usually associated with high local concentrations of reactive oxygen species and pH decrease, the device's output was considerably different. Specifically, the device's fluorescence emission significantly decreased, while the magnetic resonance signal T2 increased. Further studies identified that the changes in the device's output are attributed to inactivation of the sensing component's nanoceria that prevents it from successfully scavenging the generated free radicals. Interestingly, the buildup of free radical excess led to polymerization of the iron oxide nanoparticle's coating, with concomitant formation of micron size aggregates. Our studies indicate that a nanoceria-based device can be utilized for the monitoring of pro-inflammatory biomarkers, having important applications in the management of numerous ailments while eliminating nanoparticle toxicity issues.Monitoring of microenvironmental parameters is critical in healthcare and disease management. Harnessing the antioxidant activity of nanoceria and the imaging capabilities of iron oxide nanoparticles in a device setup, we were able to image changes in the device's aqueous milieu. The device was able to convey and process changes in the microenvironment's pH and reactive oxygen species' concentration, distinguishing physiological from abnormal levels. As a result under physiological and transient inflammatory conditions, the device's fluorescence and magnetic resonance signals, emanating from multimodal iron oxide nanoparticles, were similar. However, under chronic inflammatory conditions that are usually associated with high local concentrations of reactive oxygen species and pH decrease, the device's output was considerably different. Specifically, the device's fluorescence emission significantly decreased, while the magnetic resonance signal T2 increased. Further studies identified that the changes in the device's output are attributed to inactivation of the sensing component's nanoceria that prevents it from successfully scavenging the generated free radicals. Interestingly, the buildup of free radical excess led to polymerization of the iron oxide nanoparticle's coating, with concomitant formation of micron size aggregates. Our studies indicate that a nanoceria-based device can be utilized for the monitoring of pro-inflammatory biomarkers, having important applications in the management of numerous ailments while eliminating nanoparticle toxicity issues. Electronic supplementary information (ESI) available: ESI figures. See DOI: 10.1039/c2nr11956k

Biosynthesis, Antimicrobial and Cytotoxic Effect of Silver Nanoparticles Using a Novel Nocardiopsis sp. MBRC-1

PubMed Central

Manivasagan, Panchanathan; Senthilkumar, Kalimuthu; Sivakumar, Kannan; Kim, Se-Kwon

2013-01-01

The biosynthesis of nanoparticles has been proposed as a cost effective environmental friendly alternative to chemical and physical methods. Microbial synthesis of nanoparticles is under exploration due to wide biomedical applications, research interest in nanotechnology and microbial biotechnology. In the present study, an ecofriendly process for the synthesis of nanoparticles using a novel Nocardiopsis sp. MBRC-1 has been attempted. We used culture supernatant of Nocardiopsis sp. MBRC-1 for the simple and cost effective green synthesis of silver nanoparticles. The reduction of silver ions occurred when silver nitrate solution was treated with the Nocardiopsis sp. MBRC-1 culture supernatant at room temperature. The nanoparticles were characterized by UV-visible, TEM, FE-SEM, EDX, FTIR, and XRD spectroscopy. The nanoparticles exhibited an absorption peak around 420 nm, a characteristic surface plasmon resonance band of silver nanoparticles. They were spherical in shape with an average particle size of 45 ± 0.15 nm. The EDX analysis showed the presence of elemental silver signal in the synthesized nanoparticles. The FTIR analysis revealed that the protein component in the form of enzyme nitrate reductase produced by the isolate in the culture supernatant may be responsible for reduction and as capping agents. The XRD spectrum showed the characteristic Bragg peaks of 1 2 3, 2 0 4, 0 4 3, 1 4 4, and 3 1 1 facets of the face centered cubic silver nanoparticles and confirms that these nanoparticles are crystalline in nature. The prepared silver nanoparticles exhibited strong antimicrobial activity against bacteria and fungi. Cytotoxicity of biosynthesized AgNPs against in vitro human cervical cancer cell line (HeLa) showed a dose-response activity. IC50 value was found to be 200 μg/mL of AgNPs against HeLa cancer cells. Further studies are needed to elucidate the toxicity and the mechanism involved with antimicrobial and anticancer activity of the synthesized AgNPs as nanomedicine. PMID:23936787

Biosynthesis, antimicrobial and cytotoxic effect of silver nanoparticles using a novel Nocardiopsis sp. MBRC-1.

PubMed

Manivasagan, Panchanathan; Venkatesan, Jayachandran; Senthilkumar, Kalimuthu; Sivakumar, Kannan; Kim, Se-Kwon

2013-01-01

The biosynthesis of nanoparticles has been proposed as a cost effective environmental friendly alternative to chemical and physical methods. Microbial synthesis of nanoparticles is under exploration due to wide biomedical applications, research interest in nanotechnology and microbial biotechnology. In the present study, an ecofriendly process for the synthesis of nanoparticles using a novel Nocardiopsis sp. MBRC-1 has been attempted. We used culture supernatant of Nocardiopsis sp. MBRC-1 for the simple and cost effective green synthesis of silver nanoparticles. The reduction of silver ions occurred when silver nitrate solution was treated with the Nocardiopsis sp. MBRC-1 culture supernatant at room temperature. The nanoparticles were characterized by UV-visible, TEM, FE-SEM, EDX, FTIR, and XRD spectroscopy. The nanoparticles exhibited an absorption peak around 420 nm, a characteristic surface plasmon resonance band of silver nanoparticles. They were spherical in shape with an average particle size of 45 ± 0.15 nm. The EDX analysis showed the presence of elemental silver signal in the synthesized nanoparticles. The FTIR analysis revealed that the protein component in the form of enzyme nitrate reductase produced by the isolate in the culture supernatant may be responsible for reduction and as capping agents. The XRD spectrum showed the characteristic Bragg peaks of 1 2 3, 2 0 4, 0 4 3, 1 4 4, and 3 1 1 facets of the face centered cubic silver nanoparticles and confirms that these nanoparticles are crystalline in nature. The prepared silver nanoparticles exhibited strong antimicrobial activity against bacteria and fungi. Cytotoxicity of biosynthesized AgNPs against in vitro human cervical cancer cell line (HeLa) showed a dose-response activity. IC50 value was found to be 200 μg/mL of AgNPs against HeLa cancer cells. Further studies are needed to elucidate the toxicity and the mechanism involved with antimicrobial and anticancer activity of the synthesized AgNPs as nanomedicine.

Time-Resolved SAXS Studies of the Kinetics of Thermally Triggered Release of Encapsulated Silica Nanoparticles from Block Copolymer Vesicles

PubMed Central

2017-01-01

Silica-loaded poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) diblock copolymer vesicles are prepared in the form of concentrated aqueous dispersions via polymerization-induced self-assembly (PISA). As the concentration of silica nanoparticles present during the PISA synthesis is increased up to 35% w/w, higher degrees of encapsulation of this component within the vesicles can be achieved. After centrifugal purification to remove excess non-encapsulated silica nanoparticles, SAXS, DCP, and TGA analysis indicates encapsulation of up to hundreds of silica nanoparticles per vesicle. In the present study, the thermally triggered release of these encapsulated silica nanoparticles is examined by cooling to 0 °C for 30 min, which causes in situ vesicle dissociation. Transmission electron microscopy studies confirm the change in diblock copolymer morphology and also enable direct visualization of the released silica nanoparticles. Time-resolved small-angle X-ray scattering is used to quantify the extent of silica release over time. For an initial silica concentration of 5% w/w, cooling induces a vesicle-to-sphere transition with subsequent nanoparticle release. For higher silica concentrations (20 or 30% w/w) cooling only leads to perforation of the vesicle membranes, but silica nanoparticles are nevertheless released through the pores. For vesicles prepared in the presence of 30% w/w silica, the purified silica-loaded vesicles were cooled to 0 °C for 30 min, and SAXS patterns were collected every 15 s. A new SAXS model has been developed to determine both the mean volume fraction of encapsulated silica within the vesicles and the scattering length density. Satisfactory data fits to the experimental SAXS patterns were obtained using this model. PMID:28626247

Volume labeling with Alexa Fluor dyes and surface functionalization of highly sensitive fluorescent silica (SiO2) nanoparticles

NASA Astrophysics Data System (ADS)

Wang, Wei; Nallathamby, Prakash D.; Foster, Carmen M.; Morrell-Falvey, Jennifer L.; Mortensen, Ninell P.; Doktycz, Mitchel J.; Gu, Baohua; Retterer, Scott T.

2013-10-01

A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or ``free'' surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface-modified fluorescent particles with cultured macrophages. Differences in particle agglomeration and cell association were clearly associated with differences in observed nanoparticle toxicity. The capacity to maintain particle fluorescence while making significant changes to surface chemistry makes these particles extremely versatile and useful for studies of particle agglomeration, uptake, and transport in environmental and biological systems.A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and a polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or ``free'' surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface-modified fluorescent particles with cultured macrophages. Differences in particle agglomeration and cell association were clearly associated with differences in observed nanoparticle toxicity. The capacity to maintain particle fluorescence while making significant changes to surface chemistry makes these particles extremely versatile and useful for studies of particle agglomeration, uptake, and transport in environmental and biological systems. Electronic supplementary information (ESI) available: Cell culture preparation for dose/response imaging experiments. See DOI: 10.1039/c3nr02639f

Colloidal silver nanoparticles/rhamnolipid (SNPRL) composite as novel chemotactic antibacterial agent.

PubMed

Bharali, P; Saikia, J P; Paul, S; Konwar, B K

2013-10-01

The antibacterial activity of silver nanoparticles and rhamnolipid are well known individually. In the present research, antibacterial and chemotactic activity due to colloidal silver nanoparticles (SNP), rhamnolipid (RL) and silver nanoparticles/rhamnolipid composite (SNPRL) were evaluated using Staphylococcus aureus (MTCC3160), Escherichia coli (MTCC40), Pseudomonas aeruginosa (MTCC8163) and Bacillus subtilis (MTCC441) as test strains. Further, the SNPRL nanoparticles were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The observation clearly indicates that SNPRL shows prominent antibacterial and chemotactic activity in comparison to all of its individual precursor components. Copyright © 2013 Elsevier B.V. All rights reserved.

Towards Optimal Design of Cancer Nanomedicines: Multi-stage Nanoparticles for the Treatment of Solid Tumors.

PubMed

Stylianopoulos, Triantafyllos; Economides, Eva-Athena; Baish, James W; Fukumura, Dai; Jain, Rakesh K

2015-09-01

Conventional drug delivery systems for solid tumors are composed of a nano-carrier that releases its therapeutic load. These two-stage nanoparticles utilize the enhanced permeability and retention (EPR) effect to enable preferential delivery to tumor tissue. However, the size-dependency of the EPR, the limited penetration of nanoparticles into the tumor as well as the rapid binding of the particles or the released cytotoxic agents to cancer cells and stromal components inhibit the uniform distribution of the drug and the efficacy of the treatment. Here, we employ mathematical modeling to study the effect of particle size, drug release rate and binding affinity on the distribution and efficacy of nanoparticles to derive optimal design rules. Furthermore, we introduce a new multi-stage delivery system. The system consists of a 20-nm primary nanoparticle, which releases 5-nm secondary particles, which in turn release the chemotherapeutic drug. We found that tuning the drug release kinetics and binding affinities leads to improved delivery of the drug. Our results also indicate that multi-stage nanoparticles are superior over two-stage nano-carriers provided they have a faster drug release rate and for high binding affinity drugs. Furthermore, our results suggest that smaller nanoparticles achieve better treatment outcome.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques.

PubMed

Plascencia-Villa, Germán; Starr, Clarise R; Armstrong, Linda S; Ponce, Arturo; José-Yacamán, Miguel

2012-11-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO(2), TiO(2) and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO(2) and TiO(2), whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution.

Comparative study of magnetic ordering in bulk and nanoparticles of Sm0.65Ca0.35MnO3: Magnetization and electron magnetic resonance measurements

NASA Astrophysics Data System (ADS)

Goveas, Lora Rita; Anuradha, K. N.; Bhagyashree, K. S.; Bhat, S. V.

2015-05-01

To explore the effect of size reduction to nanoscale on the hole doped Sm0.65Ca0.35MnO3 compound, dc magnetic measurements and electron magnetic resonance (EMR) were done on bulk and nanoparticle samples in the temperature range 10 ≤ T ≤ 300 K. Magnetization measurement showed that the bulk sample undergoes a charge ordering transition at 240 K and shows a mixed magnetic phase at low temperature. However, the nanosample underwent a ferromagnetic transition at 75 K, and the charge ordered state was destabilized on size reduction down to nanoscale. The low-temperature ferromagnetic component is found to be enhanced in nanoparticles as compared to their bulk counterpart. Interestingly around room temperature, bulk particles show higher magnetization where as at low temperature nanoparticles show higher magnetization. Ferromagnetism in the bulk is due to super exchange where as ferromagnetism in nanoparticles is due to uncompensated spins of the surface layer. Temperature variation of EMR parameters correlates well with the results of magnetic measurements. The magnetic behaviour of the nanoparticles is understood in terms of the core shell scenario.

Theory for nanoparticle retention time in the helical channel of quadrupole magnetic field-flow fractionation

NASA Astrophysics Data System (ADS)

Williams, P. Stephen; Carpino, Francesca; Zborowski, Maciej

2009-05-01

Quadrupole magnetic field-flow fractionation (QMgFFF) is a separation and characterization technique for magnetic nanoparticles such as those used for cell labeling and for targeted drug therapy. A helical separation channel is used to efficiently exploit the quadrupole magnetic field. The fluid and sample components therefore have angular and longitudinal components to their motion in the thin annular space occupied by the helical channel. The retention ratio is defined as the ratio of the times for non-retained and a retained material to pass through the channel. Equations are derived for the respective angular and longitudinal components to retention ratio.

Therapeutic effect of apatinib-loaded nanoparticles on diabetes-induced retinal vascular leakage.

PubMed

Jeong, Ji Hoon; Nguyen, Hong Khanh; Lee, Jung Eun; Suh, Wonhee

2016-01-01

Apatinib, a novel and selective inhibitor of vascular endothelial growth factor (VEGF) receptor 2, has been demonstrated recently to exhibit anticancer efficacy by inhibiting the VEGF signaling pathway. Given the importance of VEGF in retinal vascular leakage, the present study was designed to investigate whether apatinib-loaded polymeric nanoparticles inhibit VEGF-mediated retinal vascular hyperpermeability and block diabetes-induced retinal vascular leakage. For the delivery of water-insoluble apatinib, the drug was encapsulated in nanoparticles composed of human serum albumin (HSA)-conjugated polyethylene glycol (PEG). In vitro paracellular permeability and transendothelial electric resistance assays showed that apatinib-loaded HSA-PEG (Apa-HSA-PEG) nanoparticles significantly inhibited VEGF-induced endothelial hyperpermeability in human retinal microvascular endothelial cells. In addition, they substantially reduced the VEGF-induced junctional loss and internalization of vascular endothelial-cadherin, a major component of endothelial junction complexes. In vivo intravitreal injection of Apa-HSA-PEG nanoparticles in mice blocked VEGF-induced retinal vascular leakage. These in vitro and in vivo data indicated that Apa-HSA-PEG nanoparticles efficiently blocked VEGF-induced breakdown of the blood-retinal barrier. In vivo experiments with streptozotocin-induced diabetic mice showed that an intravitreal injection of Apa-HSA-PEG nanoparticles substantially inhibited diabetes-induced retinal vascular leakage. These results demonstrated, for the first time, that apatinib-loaded nanoparticles may be a promising therapeutic agent for the prevention and treatment of diabetes-induced retinal vascular disorders.

Therapeutic effect of apatinib-loaded nanoparticles on diabetes-induced retinal vascular leakage

PubMed Central

Jeong, Ji Hoon; Nguyen, Hong Khanh; Lee, Jung Eun; Suh, Wonhee

2016-01-01

Apatinib, a novel and selective inhibitor of vascular endothelial growth factor (VEGF) receptor 2, has been demonstrated recently to exhibit anticancer efficacy by inhibiting the VEGF signaling pathway. Given the importance of VEGF in retinal vascular leakage, the present study was designed to investigate whether apatinib-loaded polymeric nanoparticles inhibit VEGF-mediated retinal vascular hyperpermeability and block diabetes-induced retinal vascular leakage. For the delivery of water-insoluble apatinib, the drug was encapsulated in nanoparticles composed of human serum albumin (HSA)-conjugated polyethylene glycol (PEG). In vitro paracellular permeability and transendothelial electric resistance assays showed that apatinib-loaded HSA-PEG (Apa-HSA-PEG) nanoparticles significantly inhibited VEGF-induced endothelial hyperpermeability in human retinal microvascular endothelial cells. In addition, they substantially reduced the VEGF-induced junctional loss and internalization of vascular endothelial-cadherin, a major component of endothelial junction complexes. In vivo intravitreal injection of Apa-HSA-PEG nanoparticles in mice blocked VEGF-induced retinal vascular leakage. These in vitro and in vivo data indicated that Apa-HSA-PEG nanoparticles efficiently blocked VEGF-induced breakdown of the blood–retinal barrier. In vivo experiments with streptozotocin-induced diabetic mice showed that an intravitreal injection of Apa-HSA-PEG nanoparticles substantially inhibited diabetes-induced retinal vascular leakage. These results demonstrated, for the first time, that apatinib-loaded nanoparticles may be a promising therapeutic agent for the prevention and treatment of diabetes-induced retinal vascular disorders. PMID:27462154

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.

PLGA nanoparticles from nano-emulsion templating as imaging agents: Versatile technology to obtain nanoparticles loaded with fluorescent dyes.

PubMed

Fornaguera, C; Feiner-Gracia, N; Calderó, G; García-Celma, M J; Solans, C

2016-11-01

The interest in polymeric nanoparticles as imaging systems for biomedical applications has increased notably in the last decades. In this work, PLGA nanoparticles, prepared from nano-emulsion templating, have been used to prepare novel fluorescent imaging agents. Two model fluorescent dyes were chosen and dissolved in the oil phase of the nano-emulsions together with PLGA. Nano-emulsions were prepared by the phase inversion composition (PIC) low-energy method. Fluorescent dye-loaded nanoparticles were obtained by solvent evaporation of nano-emulsion templates. PLGA nanoparticles loaded with the fluorescent dyes showed hydrodynamic radii lower than 40nm; markedly lower than those reported in previous studies. The small nanoparticle size was attributed to the nano-emulsification strategy used. PLGA nanoparticles showed negative surface charge and enough stability to be used for biomedical imaging purposes. Encapsulation efficiencies were higher than 99%, which was also attributed to the nano-emulsification approach as well as to the low solubility of the dyes in the aqueous component. Release kinetics of both fluorescent dyes from the nanoparticle dispersions was pH-independent and sustained. These results indicate that the dyes could remain encapsulated enough time to reach any organ and that the decrease of the pH produced during cell internalization by the endocytic route would not affect their release. Therefore, it can be assumed that these nanoparticles are appropriate as systemic imaging agents. In addition, in vitro toxicity tests showed that nanoparticles are non-cytotoxic. Consequently, it can be concluded that the preparation of PLGA nanoparticles from nano-emulsion templating represents a very versatile technology that enables obtaining biocompatible, biodegradable and safe imaging agents suitable for biomedical purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

Environmental nanoparticles are significantly over-expressed in acute myeloid leukemia.

PubMed

Visani, G; Manti, A; Valentini, L; Canonico, B; Loscocco, F; Isidori, A; Gabucci, E; Gobbi, P; Montanari, S; Rocchi, M; Papa, S; Gatti, A M

2016-11-01

The increase in the incidence of acute myeloid leukemia (AML) may suggest a possible environmental etiology. PM2.5 was declared by IARC a Class I carcinogen. No report has focused on particulate environmental pollution together with AML. The study investigated the presence and composition of particulate matter in blood with a Scanning Electron Microscope coupled with an Energy Dispersive Spectroscope, a sensor capable of identifying the composition of foreign bodies. 38 peripheral blood samples, 19 AML cases and 19 healthy controls, were analyzed. A significant overload of particulate matter-derived nanoparticles linked or aggregated to blood components was found in AML patients, while almost absent in matched healthy controls. Two-tailed Student's t-test, MANOVA and Principal Component Analysis indicated that the total numbers of aggregates and particles were statistically different between cases and controls (MANOVA, P<0.001 and P=0.009 respectively). The particles detected showed to contain highly-reactive, non-biocompatible and non-biodegradable metals; in particular, micro- and nano-sized particles grouped in organic/inorganic clusters, with statistically higher frequency of a subgroup of elements in AML samples. The demonstration, for the first time, of an overload of nanoparticles linked to blood components in AML patients could be the basis for a possible, novel pathogenetic mechanism for AML development. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Jun, Young -Shin; Kim, Doyoon; Neil, Chelsea W.

Here, mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth’s crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolutionmore » of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.« less

Surface interactions between gold nanoparticles and biochar

USDA-ARS?s Scientific Manuscript database

Engineered nanomaterials are directly applied to agricultural soils as a part of pesticide/fertilize formulations and sludge/manure amendments. Yet, no prior reports are available on the extent and reversibility of gold nanoparticles (nAu) retention by soil components including charcoal black carbo...

The potential risks of nanomaterials: a review carried out for ECETOC

PubMed Central

Borm, Paul JA; Robbins, David; Haubold, Stephan; Kuhlbusch, Thomas; Fissan, Heinz; Donaldson, Ken; Schins, Roel; Stone, Vicki; Kreyling, Wolfgang; Lademann, Jurgen; Krutmann, Jean; Warheit, David; Oberdorster, Eva

2006-01-01

During the last few years, research on toxicologically relevant properties of engineered nanoparticles has increased tremendously. A number of international research projects and additional activities are ongoing in the EU and the US, nourishing the expectation that more relevant technical and toxicological data will be published. Their widespread use allows for potential exposure to engineered nanoparticles during the whole lifecycle of a variety of products. When looking at possible exposure routes for manufactured Nanoparticles, inhalation, dermal and oral exposure are the most obvious, depending on the type of product in which Nanoparticles are used. This review shows that (1) Nanoparticles can deposit in the respiratory tract after inhalation. For a number of nanoparticles, oxidative stress-related inflammatory reactions have been observed. Tumour-related effects have only been observed in rats, and might be related to overload conditions. There are also a few reports that indicate uptake of nanoparticles in the brain via the olfactory epithelium. Nanoparticle translocation into the systemic circulation may occur after inhalation but conflicting evidence is present on the extent of translocation. These findings urge the need for additional studies to further elucidate these findings and to characterize the physiological impact. (2) There is currently little evidence from skin penetration studies that dermal applications of metal oxide nanoparticles used in sunscreens lead to systemic exposure. However, the question has been raised whether the usual testing with healthy, intact skin will be sufficient. (3) Uptake of nanoparticles in the gastrointestinal tract after oral uptake is a known phenomenon, of which use is intentionally made in the design of food and pharmacological components. Finally, this review indicates that only few specific nanoparticles have been investigated in a limited number of test systems and extrapolation of this data to other materials is not possible. Air pollution studies have generated indirect evidence for the role of combustion derived nanoparticles (CDNP) in driving adverse health effects in susceptible groups. Experimental studies with some bulk nanoparticles (carbon black, titanium dioxide, iron oxides) that have been used for decades suggest various adverse effects. However, engineered nanomaterials with new chemical and physical properties are being produced constantly and the toxicity of these is unknown. Therefore, despite the existing database on nanoparticles, no blanket statements about human toxicity can be given at this time. In addition, limited ecotoxicological data for nanomaterials precludes a systematic assessment of the impact of Nanoparticles on ecosystems. PMID:16907977

A simple way to prepare Au@polypyrrole/Fe3O4 hollow capsules with high stability and their application in catalytic reduction of methylene blue dye

NASA Astrophysics Data System (ADS)

Yao, Tongjie; Cui, Tieyu; Wang, Hao; Xu, Linxu; Cui, Fang; Wu, Jie

2014-06-01

Metal nanoparticles are promising catalysts for dye degradation in treating wastewater despite the challenges of recycling and stability. In this study, we have introduced a simple way to prepare Au@polypyrrole (PPy)/Fe3O4 catalysts with Au nanoparticles embedded in a PPy/Fe3O4 capsule shell. The PPy/Fe3O4 capsule shell used as a support was constructed in one-step, which not only dramatically simplified the preparation process, but also easily controlled the magnetic properties of the catalysts through adjusting the dosage of FeCl2.4H2O. The component Au nanoparticles could catalyze the reduction of methylene blue dye with NaBH4 as a reducing agent and the reaction rate constant was calculated through the pseudo-first-order reaction equation. The Fe3O4 nanoparticles permitted quick recycling of the catalysts with a magnet due to their room-temperature superparamagnetic properties; therefore, the catalysts exhibited good reusability. In addition to catalytic activity and reusability, stability is also an important property for catalysts. Because both Au and Fe3O4 nanoparticles were wrapped in the PPy shell, compared with precursor polystyrene/Au composites and bare Fe3O4 nanoparticles, the stability of Au@PPy/Fe3O4 hollow capsules was greatly enhanced. Since the current method is simple and flexible to create recyclable catalysts with high stability, it would promote the practicability of metal nanoparticle catalysts in industrial polluted water treatment.Metal nanoparticles are promising catalysts for dye degradation in treating wastewater despite the challenges of recycling and stability. In this study, we have introduced a simple way to prepare Au@polypyrrole (PPy)/Fe3O4 catalysts with Au nanoparticles embedded in a PPy/Fe3O4 capsule shell. The PPy/Fe3O4 capsule shell used as a support was constructed in one-step, which not only dramatically simplified the preparation process, but also easily controlled the magnetic properties of the catalysts through adjusting the dosage of FeCl2.4H2O. The component Au nanoparticles could catalyze the reduction of methylene blue dye with NaBH4 as a reducing agent and the reaction rate constant was calculated through the pseudo-first-order reaction equation. The Fe3O4 nanoparticles permitted quick recycling of the catalysts with a magnet due to their room-temperature superparamagnetic properties; therefore, the catalysts exhibited good reusability. In addition to catalytic activity and reusability, stability is also an important property for catalysts. Because both Au and Fe3O4 nanoparticles were wrapped in the PPy shell, compared with precursor polystyrene/Au composites and bare Fe3O4 nanoparticles, the stability of Au@PPy/Fe3O4 hollow capsules was greatly enhanced. Since the current method is simple and flexible to create recyclable catalysts with high stability, it would promote the practicability of metal nanoparticle catalysts in industrial polluted water treatment. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00023d

Influence of the type of solvent on the development of superhydrophobicity from silane-based solution containing nanoparticles

NASA Astrophysics Data System (ADS)

Pantoja, M.; Abenojar, J.; Martinez, M. A.

2017-03-01

Superhydrophobic surfaces are very appealing for numerous industrial applications due to their self-cleaning capacity. Although there are different methods to manufacture superhydrophobic surfaces, some of them do not keep the aesthetic appearance of the neat surface. Sol-gel processes are a valid alternative when transparent coatings are desired. The main goal of this research is to study the viability of this method by making superhydrophobic coatings from silane-based solution containing SiO2 nanoparticles. The effect of using different solvents is investigated, as well as the role played by the different components of the solution (silane, nanoparticles and solvent). Solutions of methyltrimethoxisilane (MTS) and tetraethoxysilane (TEOS) and 1% of SiO2 (%wt) were prepared with different solvents (ethanol, ethanol/water and white spirit). The hydrophobicity of the developed coatings is studied using contact angle measurements, while the aesthetic appearance is evaluated with gloss and color measurements. Also, infrared spectroscopy, dynamic light scattering (DSL), and surface tension measurements are used to study the silane solutions. The results show that the capacity of solvents to promote the dispersion of the nanoparticles is crucial to ensuring superhydrophobicity, since these agglomerates provide the micro- and nano- surface roughness required to get a hierarchical structure. However, the combined use of silanes and nanoparticles is key to make a superhydrophobic surface because physical (the surface roughness provided by nanoparticles) and chemical characteristics (hydrophobicity provided by silanes) are coupled.

Multifunctional aptamer-based nanoparticles for targeted drug delivery to circumvent cancer resistance.

PubMed

Liu, Juan; Wei, Tuo; Zhao, Jing; Huang, Yuanyu; Deng, Hua; Kumar, Anil; Wang, Chenxuan; Liang, Zicai; Ma, Xiaowei; Liang, Xing-Jie

2016-06-01

By its unique advantages over traditional medicine, nanomedicine has offered new strategies for cancer treatment. In particular, the development of drug delivery strategies has focused on nanoscale particles to improve bioavailability. However, many of these nanoparticles are unable to overcome tumor resistance to chemotherapeutic agents. Recently, new opportunities for drug delivery have been provided by oligonucleotides that can self-assemble into three-dimensional nanostructures. In this work, we have designed and developed functional DNA nanostructures to deliver the chemotherapy drug doxorubicin (Dox) to resistant cancer cells. These nanostructures have two components. The first component is a DNA aptamer, which forms a dimeric G-quadruplex nanostructure to target cancer cells by binding with nucleolin. The second component is double-stranded DNA (dsDNA), which is rich in -GC- base pairs that can be applied for Dox delivery. We demonstrated that Dox was able to efficiently intercalate into dsDNA and this intercalation did not affect the aptamer's three-dimensional structure. In addition, the Aptamer-dsDNA (ApS) nanoparticle showed good stability and protected the dsDNA from degradation in bovine serum. More importantly, the ApS&Dox nanoparticle efficiently reversed the resistance of human breast cancer cells to Dox. The mechanism circumventing doxorubicin resistance by ApS&Dox nanoparticles may be predominantly by cell cycle arrest in S phase, effectively increased cell uptake and decreased cell efflux of doxorubicin. Furthermore, the ApS&Dox nanoparticles could effectively inhibit tumor growth, while less cardiotoxicity was observed. Overall, this functional DNA nanostructure provides new insights into the design of nanocarriers to overcome multidrug resistance through targeted drug delivery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aqueous Nanoparticle Polymer Solar Cells: Effects of Surfactant Concentration and Processing on Device Performance

PubMed Central

2017-01-01

Polymer solar cells based on PDPP5T and PCBM as donor and acceptor materials, respectively, were processed from aqueous nanoparticle dispersions. Careful monitoring and optimization of the concentration of free and surface-bound surfactants in the dispersion, by measuring the conductivity and ζ-potential, is essential to avoid aggregation of nanoparticles at low concentration and dewetting of the film at high concentration. The surfactant concentration is crucial for creating reproducible processing conditions that aid in further developing aqueous nanoparticle processed solar cells. In addition, the effects of adding ethanol, of aging the dispersion, and of replacing [60]PCBM with [70]PCBM to enhance light absorption were studied. The highest power conversion efficiencies (PCEs) obtained are 2.0% for [60]PCBM and 2.4% for [70]PCBM-based devices. These PCEs are limited by bimolecular recombination of photogenerated charges. Cryo-TEM reveals that the two components phase separate in the nanoparticles, forming a PCBM-rich core and a PDPP5T-rich shell and causing a nonoptimal film morphology. PMID:28345859

Manipulating the Ordered Nanostructure of Self-Assembled Monoolein and Phytantriol Nanoparticles with Unsaturated Fatty Acids.

PubMed

Tran, Nhiem; Mulet, Xavier; Hawley, Adrian M; Fong, Celesta; Zhai, Jiali; Le, Tu C; Ratcliffe, Julian; Drummond, Calum J

2018-02-27

Mesophase structures of self-assembled lyotropic liquid crystalline nanoparticles are important factors that directly influence their ability to encapsulate and release drugs and their biological activities. However, it is difficult to predict and precisely control the mesophase behavior of these materials, especially in complex systems with several components. In this study, we report the controlled manipulation of mesophase structures of monoolein (MO) and phytantriol (PHYT) nanoparticles by adding unsaturated fatty acids (FAs). By using high throughput formulation and small-angle X-ray scattering characterization methods, the effects of FAs chain length, cis-trans isomerism, double bond location, and level of chain unsaturation on self-assembled systems are determined. Additionally, the influence of temperature on the phase behavior of these nanoparticles is analyzed. We found that in general, the addition of unsaturated FAs to MO and PHYT induces the formation of mesophases with higher Gaussian surface curvatures. As a result, a rich variety of lipid polymorphs are found to correspond with the increasing amounts of FAs. These phases include inverse bicontinuous cubic, inverse hexagonal, and discrete micellar cubic phases and microemulsion. However, there are substantial differences between the phase behavior of nanoparticles with trans FA, cis FAs with one double bond, and cis FAs with multiple double bonds. Therefore, the material library produced in this study will assist the selection and development of nanoparticle-based drug delivery systems with desired mesophase.

Chiral recognition of proteins having L-histidine residues on the surface with lanthanide ion complex incorporated-molecularly imprinted fluorescent nanoparticles.

PubMed

Uzun, Lokman; Uzek, Recep; Senel, Serap; Say, Ridvan; Denizli, Adil

2013-08-01

In this study, lanthanide ion complex incorporated molecularly imprinted fluorescent nanoparticles were synthesized. A combination of three novel approaches was applied for the purpose. First, lanthanide ions [Terbium(III)] were complexed with N-methacryloyl-L-histidine (MAH), polymerizable derivative of L-histidine amino acid, in order to incorporate the complex directly into the polymeric backbone. At the second stage, L-histidine molecules imprinted nanoparticles were utilized instead of whole protein imprinting in order to avoid whole drawbacks such as fragility, complexity, denaturation tendency, and conformation dependency. At the third stage following the first two steps mentioned above, imprinted L-histidine was coordinated with cupric ions [Cu(II)] to conduct the study under mild conditions. Then, molecularly imprinted fluorescent nanoparticles synthesized were used for L-histidine adsorption from aqueous solution to optimize conditions for adsorption and fluorimetric detection. Finally, usability of nanoparticles was investigated for chiral biorecognition using stereoisomer, D-histidine, racemic mixture, D,L-histidine, proteins with surface L-histidine residue, lysozyme, cytochrome C, or without ribonuclease A. The results revealed that the proposed polymerization strategy could make significant contribution to the solution of chronic problems of fluorescent component introduction into polymers. Additionally, the fluorescent nanoparticles reported here could be used for selective separation and fluorescent monitoring purposes. Copyright © 2013 Elsevier B.V. All rights reserved.

Composite nanoparticles for gene delivery.

PubMed

Wang, Yuhua; Huang, Leaf

2014-01-01

Nanoparticle-mediated gene and siRNA delivery has been an appealing area to gene therapists when they attempt to treat the diseases by manipulating the genetic information in the target cells. However, the advances in materials science could not keep up with the demand for multifunctional nanomaterials to achieve desired delivery efficiency. Researchers have thus taken an alternative approach to incorporate various materials into single composite nanoparticle using different fabrication methods. This approach allows nanoparticles to possess defined nanostructures as well as multiple functionalities to overcome the critical extracellular and intracellular barriers to successful gene delivery. This chapter will highlight the advances of fabrication methods that have the most potential to translate nanoparticles from bench to bedside. Furthermore, a major class of composite nanoparticle-lipid-based composite nanoparticles will be classified based on the components and reviewed in details.

Tuning structure of oppositely charged nanoparticle and protein complexes

NASA Astrophysics Data System (ADS)

Kumar, Sugam; Aswal, V. K.; Callow, P.

2014-04-01

Small-angle neutron scattering (SANS) has been used to probe the structures of anionic silica nanoparticles (LS30) and cationic lyszyme protein (M.W. 14.7kD, I.P. ˜ 11.4) by tuning their interaction through the pH variation. The protein adsorption on nanoparticles is found to be increasing with pH and determined by the electrostatic attraction between two components as well as repulsion between protein molecules. We show the strong electrostatic attraction between nanoparticles and protein molecules leads to protein-mediated aggregation of nanoparticles which are characterized by fractal structures. At pH 5, the protein adsorption gives rise to nanoparticle aggregation having surface fractal morphology with close packing of nanoparticles. The surface fractals transform to open structures of mass fractal morphology at higher pH (7 and 9) on approaching isoelectric point (I.P.).

Multifunctional polymeric nanoparticles doubly loaded with SPION and ceftiofur retain their physical and biological properties.

PubMed

Solar, Paula; González, Guillermo; Vilos, Cristian; Herrera, Natalia; Juica, Natalia; Moreno, Mabel; Simon, Felipe; Velásquez, Luis

2015-02-13

Advances in nanostructure materials are leading to novel strategies for drug delivery and targeting, contrast media for magnetic resonance imaging (MRI), agents for hyperthermia and nanocarriers. Superparamagnetic iron oxide nanoparticles (SPIONs) are useful for all of these applications, and in drug-release systems, SPIONs allow for the localization, direction and concentration of drugs, providing a broad range of therapeutic applications. In this work, we developed and characterized polymeric nanoparticles based on poly (3-hydroxybutyric acid-co-hydroxyvaleric acid) (PHBV) functionalized with SPIONs and/or the antibiotic ceftiofur. These nanoparticles can be used in multiple biomedical applications, and the hybrid SPION-ceftiofur nanoparticles (PHBV/SPION/CEF) can serve as a multifunctional platform for the diagnosis and treatment of cancer and its associated bacterial infections. Morphological examination using transmission electron microscopy (TEM) showed nanoparticles with a spherical shape and a core-shell structure. The particle size was evaluated using dynamic light scattering (DLS), which revealed a diameter of 243.0 ± 17 nm. The efficiency of encapsulation (45.5 ± 0.6% w/v) of these polymeric nanoparticles was high, and their components were evaluated using spectroscopy. UV-VIS, FTIR and DSC showed that all of the nanoparticles contained the desired components, and these compounds interacted to form a nanocomposite. Using the agar diffusion method and live/dead bacterial viability assays, we demonstrated that these nanoparticles have antimicrobial properties against Escherichia coli, and they retain their magnetic properties as measured using a vibrating sample magnetometer (VSM). Cytotoxicity was assessed in HepG2 cells using live/dead viability assays and MTS, and these assays showed low cytotoxicity with IC50 > 10 mg/mL nanoparticles. Our results indicate that hybrid and multifunctional PHBV/SPION/CEF nanoparticles are suitable as a superparamagnetic drug delivery system that can guide, concentrate and site-specifically release drugs with antibacterial activity.

A Study on Dielectric Properties of Cadmium Sulfide-Zinc Sulfide Core-Shell Nanocomposites for Application as Nanoelectronic Filter Component in the Microwave Domain

NASA Astrophysics Data System (ADS)

Devi, Jutika; Datta, Pranayee

2018-07-01

Complex permittivities of cadmium sulfide (CdS), zinc sulfide (ZnS), and of cadmium sulfide-zinc sulfide (CdS/ZnS) core-shell nanoparticles embedded in a polyvinyl alcohol matrix (PVA) were measured in liquid phase using a VectorNetwork Analyzer in the frequency range of 500 MHz-10 GHz. These nanocomposites are modeled as an embedded capacitor, and their electric field distribution and polarization have been studied using COMSOL Multiphysics software. By varying the thickness of the shell and the number of inclusions, the capacitance values were estimated. It was observed that CdS, ZnS and CdS/ZnS core-shell nanoparticles embedded in a polyvinyl alcohol matrix show capacitive behavior. There is a strong influence of the dielectric properties in the capacitive behavior of the embedded nanocapacitor. The capping matrix, position and filling factors of nanoinclusions all affect the capacitive behavior of the tested nanocomposites. Application of the CdS, ZnS and CdS/ZnS core-shell nanocomposite as the passive low-pass filter circuit has also been investigated. From the present study, it has been found that CdS/ZnS core-shell nanoparticles embedded in PVA matrix are potential structures for application as nanoelectronic filter components in different areas of communication.

A Study on Dielectric Properties of Cadmium Sulfide-Zinc Sulfide Core-Shell Nanocomposites for Application as Nanoelectronic Filter Component in the Microwave Domain

NASA Astrophysics Data System (ADS)

Devi, Jutika; Datta, Pranayee

2018-03-01

Complex permittivities of cadmium sulfide (CdS), zinc sulfide (ZnS), and of cadmium sulfide-zinc sulfide (CdS/ZnS) core-shell nanoparticles embedded in a polyvinyl alcohol matrix (PVA) were measured in liquid phase using a VectorNetwork Analyzer in the frequency range of 500 MHz-10 GHz. These nanocomposites are modeled as an embedded capacitor, and their electric field distribution and polarization have been studied using COMSOL Multiphysics software. By varying the thickness of the shell and the number of inclusions, the capacitance values were estimated. It was observed that CdS, ZnS and CdS/ZnS core-shell nanoparticles embedded in a polyvinyl alcohol matrix show capacitive behavior. There is a strong influence of the dielectric properties in the capacitive behavior of the embedded nanocapacitor. The capping matrix, position and filling factors of nanoinclusions all affect the capacitive behavior of the tested nanocomposites. Application of the CdS, ZnS and CdS/ZnS core-shell nanocomposite as the passive low-pass filter circuit has also been investigated. From the present study, it has been found that CdS/ZnS core-shell nanoparticles embedded in PVA matrix are potential structures for application as nanoelectronic filter components in different areas of communication.

Detrital and Authigenic Magnetic Micro- and Nanoparticles in Pelagic Sediments of the Equatorial Atlantic

NASA Astrophysics Data System (ADS)

Franke, C.; von Dobeneck, T.; Dekkers, M.

2004-12-01

Magnetic paleofield and paleoenvironmental information of marine sediments is mostly carried by submicron magnetic particles from various sources. Most existing studies make plausible, but largely unconfirmed assumptions about the origin, mineralogy and grain size of the magnetic mineral assemblages of pelagic sediments. This study intends to provide a detailed characterization of magnetic micro- and nanoparticles in oxic to mildly suboxic sedimentary environments of the Equatorial Atlantic and compares three sites (Ceará Rise, Mid Atlantic Ridge (MAR), Sierra Leone Rise) along a W-E transect. This region offers magnetic particle sources such as continental dust, fluvial discharge and weathering of ocean ridge basalts. Remanence, hysteresis, low- and high-temperature rock magnetic investigations were performed on bulk sediments, magnetic extracts and heavy liquid separates and were combined with analytic scanning (SEM) and transmission (TEM) electron microscopy. Curie temperatures between 580 and 600° C indicate oxidized magnetite as the major low coercivity component in all samples. The Verwey transition ( ˜110 K) is weakly expressed in the samples from the Ceará Rise and the MAR and disappears at the Sierra Leone Rise. SEM studies on the magnetic extracts show that the quantitative main components are detrital titanomagnetite particles with increasing Ti-content throughout the transect towards the East. Magnetite particles with very low to zero Ti-content provide about one third of the detrital component. They often show shrinking cracks indicating external maghemitization. Further components are octahedral titanomagnetite crystals, silicates with (titano-) magnetite inclusions and spherules with low Ti-content. An important high coercive component, most likely goethite, is unsaturated at 2.5 T and missing in the magnetic extracts. It is manifested by a large discrepancy of the slopes in field cooling and the zero field cooling low-temperature curves, which disappear after heating to 340° C. Shape, grain size, roundness as well as the degree of preservation of the magnetic grains give insight into the transport mechanisms and regional provenances of the various components. The close coupling of ARM and IRM signals hints at a single source mechanism, eolian dust input, for micro- and nanoparticle fractions in the East of the transect. Therefore, the ARM/IRM ratio indicates mainly grain size variations related to varying wind intensity. In the western Equatorial Atlantic, the accumulation rates of the micro- and nanoparticles are much more weakly coupled. The coarser fraction is reflecting sea level controlled Amazon discharge while the fine fraction is yet to be identified by TEM. In contrary to the eastern part, the ARM/IRM signal of this region expresses rather a grain size mixing than sorting regime.

Surface functionalized magnetic nanoparticles for cancer therapy applications

NASA Astrophysics Data System (ADS)

Wydra, Robert John

Despite recent advances, cancer remains the second leading cause of deaths in the United States. Magnetic nanoparticles have found various applications in cancer research as drug delivery platforms, enhanced contrast agents for improved diagnostic imaging, and the delivery of thermal energy as standalone therapy. Iron oxide nanoparticles absorb the energy from an alternating magnetic field and convert it into heat through Brownian and Neel relaxations. To better utilize magnetic nanoparticles for cancer therapy, surface functionalization is essential for such factors as decreasing cytotoxicity of healthy tissue, extending circulation time, specific targeting of cancer cells, and manage the controlled delivery of therapeutics. In the first study, iron oxide nanoparticles were coated with a poly(ethylene glycol) (PEG) based polymer shell. The PEG coating was selected to prevent protein adsorption and thus improve circulation time and minimize host response to the nanoparticles. Thermal therapy application feasibility was demonstrated in vitro with a thermoablation study on lung carcinoma cells. Building on the thermal therapy demonstration with iron oxide nanoparticles, the second area of work focused on intracellular delivery. Nanoparticles can be appropriately tailored to enter the cell and deliver energy on the nanoscale eliminating individual cancer cells. The underlying mechanism of action is still under study, and we were interested in determining the role of reactive oxygen species (ROS) catalytically generated from the surface of iron oxide nanoparticles in this measured cytotoxicity. When exposed to an AMF, the nanoscale heating effects are capable of enhancing the Fenton-like generation of ROS determined through a methylene blue degradation assay. To deliver this enhanced ROS effect to cells, monosaccharide coated nanoparticles were developed and successfully internalized by colon cancer cell lines. Upon AMF exposure, there was a measured increase in cellular ROS and apoptosis that was attributed to lysosomal disruption since the surface functionalization selected inhibited the Fenton-like surface chemistry. To overcome this surface inhibition, a biodegradable poly(beta-amino ester) (PBAE) polymer coating was synthesized to deliver bare iron oxide to intracellular components. Delivering enhanced ROS to cancer cells is a promising new route of therapy that deserves future studies.

Versatile organic (fullerene)-inorganic (CdTe nanoparticle) nanoensembles.

PubMed

Guldi, Dirk M; Zilbermann, Israel; Anderson, Greg; Kotov, Nicholas A; Tagmatarchis, Nikos; Prato, Maurizio

2004-11-10

Novel organic (positively charged fullerene)-inorganic (negatively charged CdTe nanoparticle) nanoensembles were devised through electrostatic interactions and probed as versatile donor-acceptor hybrids. Photoirradiation of their homogeneous solutions, containing the electrostatically packed components, let to very long-lived (1.3 ms) charge separated states.

Experimental evaluation of the magnetic properties of commercially available magnetic microspheres.

PubMed

Connolly, Joan; St Pierre, Timothy G; Dobson, Jon

2005-01-01

The magnetic properties of 5 commercially available magnetic microsphere samples are tested and compared with those stated by their manufacturers. A suspension of magnetic, iron oxide nanoparticles is studied for comparison. Two of the microsphere samples have magnetic properties which do not support the manufacturer's claims of superparamagnetism. The remaining 3 microsphere samples as well as the nanoparticle suspension are superparamagnetic or ferromagnetic as claimed by the manufacturers. Field cooled and zero field cooled magnetisations indicate that the non-superparamagnetic microsphere samples contain blocked magnetic particles at room temperature. This observation is supported by the open hysteresis loops of the room temperature, field dependent magnetisation measurement. There is a significant paramagnetic component in the superparamagnetic microspheres. This is also present to a lesser extent in a nanoparticle suspension.

Aggregation of gold nanoparticles followed by methotrexate release enables Raman imaging of drug delivery into cancer cells

NASA Astrophysics Data System (ADS)

Durgadas, C. V.; Sharma, C. P.; Paul, W.; Rekha, M. R.; Sreenivasan, K.

2012-09-01

This study refers an aqueous synthesis of methotrexate (MTX)-conjugated gold nanoparticles (GNPs), their interaction with HepG2 cells, and the use of Raman imaging to observe cellular internalization and drug delivery. GNPs of average size 3.5-5 nm were stabilized using the amine terminated bifunctional biocompatible copolymer and amended by conjugating MTX, an anticancer drug. The nanoparticles were released MTX at a faster rate in acidic pH and subsequently found to form aggregates. The Raman signals of cellular components were found to be enhanced by the aggregated particles enabling the mapping to visualize site-specific drug delivery. The methodology seems to have potential in optimizing the characteristics of nanodrug carriers for emptying the cargo precisely at specified sites.

Augmented cellular uptake of nanoparticles using tea catechins: effect of surface modification on nanoparticle-cell interaction

NASA Astrophysics Data System (ADS)

Lu, Yi-Ching; Luo, Pei-Chun; Huang, Chun-Wan; Leu, Yann-Lii; Wang, Tzu-Hao; Wei, Kuo-Chen; Wang, Hsin-Ell; Ma, Yunn-Hwa

2014-08-01

Nanoparticles may serve as carriers in targeted therapeutics; interaction of the nanoparticles with a biological system may determine their targeting effects and therapeutic efficacy. Epigallocatechin-3-gallate (EGCG), a major component of tea catechins, has been conjugated with nanoparticles and tested as an anticancer agent. We investigated whether EGCG may enhance nanoparticle uptake by tumor cells. Cellular uptake of a dextran-coated magnetic nanoparticle (MNP) was determined by confocal microscopy, flow cytometry or a potassium thiocyanate colorimetric method. We demonstrated that EGCG greatly enhanced interaction and/or internalization of MNPs (with or without polyethylene glycol) by glioma cells, but not vascular endothelial cells. The enhancing effects are both time- and concentration-dependent. Such effects may be induced by a simple mix of MNPs with EGCG at a concentration as low as 1-3 μM, which increased MNP uptake 2- to 7-fold. In addition, application of magnetic force further potentiated MNP uptake, suggesting a synergetic effect of EGCG and magnetic force. Because the effects of EGCG were preserved at 4 °C, but not when EGCG was removed from the culture medium prior to addition of MNPs, a direct interaction of EGCG and MNPs was implicated. Use of an MNP-EGCG composite produced by adsorption of EGCG and magnetic separation also led to an enhanced uptake. The results reveal a novel interaction of a food component and nanocarrier system, which may be potentially amenable to magnetofection, cell labeling/tracing, and targeted therapeutics.

Fundamental aspects of regenerative cerium oxide nanoparticles and their applications in nanobiotechnology

NASA Astrophysics Data System (ADS)

Patil, Swanand D.

Cerium oxide has been used extensively for various applications over the past two decades. The use of cerium oxide nanoparticles is beneficial in present applications and can open avenues for future applications. The present study utilizes the microemulsion technique to synthesize uniformly distributed cerium oxide nanoparticles. The same technique was also used to synthesize cerium oxide nanoparticles doped with trivalent elements (La and Nd). The fundamental study of cerium oxide nanoparticles identified variations in properties as a function of particle size and also due to doping with trivalent elements (La and Nd). It was found that the lattice parameter of cerium oxide nanoparticles increases with decrease in particle size. Also Raman allowed mode shift to lower energies and the peak at 464 cm-1 becomes broader and asymmetric. The size dependent changes in cerium oxide were correlated to increase in oxygen vacancy concentration in the cerium oxide lattice. The doping of cerium oxide nanoparticles with trivalent elements introduces more oxygen vacancies and expands the cerium oxide lattice further (in addition to the lattice expansion due to the size effect). The lattice expansion is greater for La-doped cerium oxide nanoparticles compared to Nd-doping due to the larger ionic radius of La compared to Nd, the lattice expansion is directly proportional to the dopant concentration. The synthesized cerium oxide nanoparticles were used to develop an electrochemical biosensor of hydrogen peroxide (H2O2). The sensor was useful to detect H2O2 concentrations as low as 1muM in water. Also the preliminary testing of the sensor on tomato stem and leaf extracts indicated that the sensor can be used in practical applications such as plant physiological studies etc. The nanomolar concentrations of cerium oxide nanoparticles were also found to be useful in decreasing ROS (reactive oxygen species) mediated cellular damages in various in vitro cell cultures. Cerium oxide nanoparticles reduced the cellular damages to the normal breast epithelial cell line (CRL 8798) induced by X-rays and to the Keratinocyte cell line induced by UV irradiation. Cerium oxide nanoparticles were also found to be neuroprotective to adult rat spinal cord and retinal neurons. We propose that cerium oxide nanoparticles act as free radical scavenger (via redox reactions on its surface) to decrease the ROS induced cellular damages. Additionally, UV-visible spectroscopic studies indicated that cerium oxide nanoparticles possess auto-regenerative property by switching its oxidation state between Ce3+ and Ce4+. The auto-regenerative antioxidant property of these nanoparticles appears to be a key component in all the biological applications discussed in the present study.

Characterization of magnetic nanoparticles using programmed quadrupole magnetic field-flow fractionation

PubMed Central

Williams, P. Stephen; Carpino, Francesca; Zborowski, Maciej

2010-01-01

Quadrupole magnetic field-flow fractionation is a relatively new technique for the separation and characterization of magnetic nanoparticles. Magnetic nanoparticles are often of composite nature having a magnetic component, which may be a very finely divided material, and a polymeric or other material coating that incorporates this magnetic material and stabilizes the particles in suspension. There may be other components such as antibodies on the surface for specific binding to biological cells, or chemotherapeutic drugs for magnetic drug delivery. Magnetic field-flow fractionation (MgFFF) has the potential for determining the distribution of the magnetic material among the particles in a given sample. MgFFF differs from most other forms of field-flow fractionation in that the magnetic field that brings about particle separation induces magnetic dipole moments in the nanoparticles, and these potentially can interact with one another and perturb the separation. This aspect is examined in the present work. Samples of magnetic nanoparticles were analysed under different experimental conditions to determine the sensitivity of the method to variation of conditions. The results are shown to be consistent and insensitive to conditions, although magnetite content appeared to be somewhat higher than expected. PMID:20732895

Ordered porous mesostructured materials from nanoparticle-block copolymer self-assembly

DOEpatents

Warren, Scott; Wiesner, Ulrich; DiSalvo, Jr., Francis J

2013-10-29

The invention provides mesostructured materials and methods of preparing mesostructured materials including metal-rich mesostructured nanoparticle-block copolymer hybrids, porous metal-nonmetal nanocomposite mesostructures, and ordered metal mesostructures with uniform pores. The nanoparticles can be metal, metal alloy, metal mixture, intermetallic, metal-carbon, metal-ceramic, semiconductor-carbon, semiconductor-ceramic, insulator-carbon or insulator-ceramic nanoparticles, or combinations thereof. A block copolymer/ligand-stabilized nanoparticle solution is cast, resulting in the formation of a metal-rich (or semiconductor-rich or insulator-rich) mesostructured nanoparticle-block copolymer hybrid. The hybrid is heated to an elevated temperature, resulting in the formation of an ordered porous nanocomposite mesostructure. A nonmetal component (e.g., carbon or ceramic) is then removed to produce an ordered mesostructure with ordered and large uniform pores.

Visible-infrared micro-spectrometer based on a preaggregated silver nanoparticle monolayer film and an infrared sensor card

NASA Astrophysics Data System (ADS)

Yang, Tao; Peng, Jing-xiao; Ho, Ho-pui; Song, Chun-yuan; Huang, Xiao-li; Zhu, Yong-yuan; Li, Xing-ao; Huang, Wei

2018-01-01

By using a preaggregated silver nanoparticle monolayer film and an infrared sensor card, we demonstrate a miniature spectrometer design that covers a broad wavelength range from visible to infrared with high spectral resolution. The spectral contents of an incident probe beam are reconstructed by solving a matrix equation with a smoothing simulated annealing algorithm. The proposed spectrometer offers significant advantages over current instruments that are based on Fourier transform and grating dispersion, in terms of size, resolution, spectral range, cost and reliability. The spectrometer contains three components, which are used for dispersion, frequency conversion and detection. Disordered silver nanoparticles in dispersion component reduce the fabrication complexity. An infrared sensor card in the conversion component broaden the operational spectral range of the system into visible and infrared bands. Since the CCD used in the detection component provides very large number of intensity measurements, one can reconstruct the final spectrum with high resolution. An additional feature of our algorithm for solving the matrix equation, which is suitable for reconstructing both broadband and narrowband signals, we have adopted a smoothing step based on a simulated annealing algorithm. This algorithm improve the accuracy of the spectral reconstruction.

Atmospheric nanoparticles in photocatalytic and thermal production of atmospheric pollutants

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

Chianelli, R.R.; Yacaman, M.J.

1997-12-31

Atmospheric aerosols which occur above heavily polluted areas such as Mexico City are characterized and found to be complex materials which have the potential to accelerate important ozone-forming reactions photocatalytically and thermocatalytically. In addition, because the particles are respirable, they represent a considerable health hazard. The aerosols consist of two intermixed components. The first component consists of amorphous carbonaceous materials of variable composition with fullerene like materials dispersed throughout. The second component is an inorganic material consisting of nanoparticles of oxides and sulfides supported on clay minerals. This inorganic component has all of the characteristics of an airborne photocatalyst. Nanoparticlesmore » of Fe{sub 2}O{sub 3}, MnO{sub 2} and FeS{sub 2} have demonstrated catalytic properties, particularly when occurring in the nanoparticle range as they do in the subject aerosol materials. These materials have band-gaps which occur in the broad solar spectrum enhancing the photocatalytic adsorption of solar radiation beyond that of the wider band-gap aluminosilicate and titanate materials which also occur in the aerosols. In addition, the materials are acidic and probably are coated with moisture when suspended in air, further enhancing the catalytic ability to crack hydrocarbons and create free radicals.« less

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.

Nanocomposites Derived from Polymers and Inorganic Nanoparticles

PubMed Central

Jeon, In-Yup; Baek, Jong-Beom

2010-01-01

Polymers are considered to be good hosting matrices for composite materials because they can easily be tailored to yield a variety of bulk physical properties. Moreover, organic polymers generally have long-term stability and good processability. Inorganic nanoparticles possess outstanding optical, catalytic, electronic and magnetic properties, which are significantly different their bulk states. By combining the attractive functionalities of both components, nanocomposites derived from organic polymers and inorganic nanoparticles are expected to display synergistically improved properties. The potential applications of the resultant nanocomposites are various, e.g. automotive, aerospace, opto-electronics, etc. Here, we review recent progress in polymer-based inorganic nanoparticle composites.

Preparation and analysis of a two-components breath figure at the nanoscale

NASA Astrophysics Data System (ADS)

Kofman, R.; Allione, M.; Celestini, F.; Barkay, Z.; Lereah, Y.

2008-12-01

Solid/liquid two-components Ga-Pb structures in isolated nanometer sized particles have been produced and studied by electron microscopy. Production is based on the breath figure technique and we investigate the way the two components are distributed. We clearly identify two growth regimes associated with the two different ways a Pb atom incorporates into a Ga nanodrop. Using TEM and SEM, the shape and microstructure of the nanoparticles are studied and the results obtained are in good agreement with the proposed model. The experimental technique used appears to be appropriate to produce Pb nanocrystals in liquid Ga nano-containers.

Synthesis of Nanoparticles in a Pulsed-Periodic Gas Discharge and Their Potential Applications

NASA Astrophysics Data System (ADS)

Ivanov, V. V.; Efimov, A. A.; Myl'nikov, D. A.; Lizunova, A. A.

2018-03-01

Conditions for the synthesis of three types nanoparticles (SnO2, Al2O3, and Ag) with typical sizes in the range of 4 to 10 nm and a performance of 0.4 g/h are employed in a pulsed-periodic gas discharge in an atmosphere of air. Spherical Ge nanoparticles with a characteristic size of 13 nm are synthesized by these means for the first time with a performance of around 10 mg/h. The specific energy consumption in the synthesis of nanoparticles is for these materials in the range of 2000 to 5000 kW h/kg. The prospects for using tinoxide nanoparticles in sensor components and jets of silver nanoparticles for aerosol printing are discussed. The merits and demerits of the pulsed gas-discharge method among other gas-phase approaches to the synthesis of nanoparticles are analyzed for the current level of development.

Synthesis and morphology of hydroxyapatite/polyethylene oxide nanocomposites with block copolymer compatibilized interfaces

NASA Astrophysics Data System (ADS)

Lee, Ji Hoon; Shofner, Meisha

2012-02-01

In order to exploit the promise of polymer nanocomposites, special consideration should be given to component interfaces during synthesis and processing. Previous results from this group have shown that nanoparticles clustered into larger structures consistent with their native shape when the polymer matrix crystallinity was high. Therefore in this research, the nanoparticles are disguised from a highly-crystalline polymer matrix by cloaking them with a matrix-compatible block copolymer. Specifically, spherical and needle-shaped hydroxyapatite nanoparticles were synthesized using a block copolymer templating method. The block copolymer used, polyethylene oxide-b-polymethacrylic acid, remained on the nanoparticle surface following synthesis with the polyethylene oxide block exposed. These nanoparticles were subsequently added to a polyethylene oxide matrix using solution processing. Characterization of the nanocomposites indicated that the copolymer coating prevented the nanoparticles from assembling into ordered clusters and that the matrix crystallinity was decreased at a nanoparticle spacing of approximately 100 nm.

Kinetic modeling of the formation and growth of inorganic nano-particles during pulverized coal char combustion in O 2/N 2 and O 2/CO 2 atmospheres

DOE PAGES

Shaddix, Christopher R.; Niu, Yanqing; Hui, Shi'en; ...

2016-08-01

In this formation of nano-particles during coal char combustion, the vaporization of inorganic components in char and the subsequent homogeneous particle nucleation, heterogeneous condensation, coagulation, and coalescence play decisive roles. Furthermore, conventional measurements cannot provide detailed information on the dynamics of nano-particle formation and evolution, In this study, a sophisticated intrinsic char kinetics model that considers ash effects (including ash film formation, ash dilution, and ash vaporization acting in tandem), both oxidation and gasification by CO 2 and H 2O, homogeneous particle nucleation, heterogeneous vapor condensation, coagulation, and and coalescence mechanisms is developed and used to compare the temporal evolutionmore » of the number and size of nano-particles during coal char particle combustion as a function of char particle size, ash content, and oxygen content in O 2/N 2 and O 2/CO 2 atmospheres .« less

Kinetic modeling of the formation and growth of inorganic nano-particles during pulverized coal char combustion in O 2/N 2 and O 2/CO 2 atmospheres

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

Shaddix, Christopher R.; Niu, Yanqing; Hui, Shi'en

In this formation of nano-particles during coal char combustion, the vaporization of inorganic components in char and the subsequent homogeneous particle nucleation, heterogeneous condensation, coagulation, and coalescence play decisive roles. Furthermore, conventional measurements cannot provide detailed information on the dynamics of nano-particle formation and evolution, In this study, a sophisticated intrinsic char kinetics model that considers ash effects (including ash film formation, ash dilution, and ash vaporization acting in tandem), both oxidation and gasification by CO 2 and H 2O, homogeneous particle nucleation, heterogeneous vapor condensation, coagulation, and and coalescence mechanisms is developed and used to compare the temporal evolutionmore » of the number and size of nano-particles during coal char particle combustion as a function of char particle size, ash content, and oxygen content in O 2/N 2 and O 2/CO 2 atmospheres .« less

Influence of silver nanoparticles on food components in wheat

NASA Astrophysics Data System (ADS)

Nawrocka, A.; Cieśla, J.

2013-01-01

During storage, grain might be affected by bacterial and fungal infections. Pathogens diminish the grain quality through contamination with excrements and second metabolites. It is very important to prevent grain from infections. Due to their antimicrobial properties, silver nanoparticles can play the role of an effective protector. The influence of nanoparticles on wheat quality was studied. The gluten parameters and falling number did not change after covering the grain with silver nanoparticles stabilized by sodium citrate. Changes in the structure of starch and gluten were investigated using Fourier-transform infrared spectroscopy. Infrared spectra of the whole meal and starch have shown a slight shift (from 1 000 to 995cm-1) of the band connected with the C-O-H bending. This displacement is probably related to the changes in sample moisture. Significant differences, corresponding to changes in the protein secondary structure, have appeared in the gluten spectra after covering.A decrease of absorbance in the amide and CH and OH regions has been observed regardless of the covering time.

Tattoo ink nanoparticles in skin tissue and fibroblasts

PubMed Central

Twigg, Peter C; Baker, Richard; Tobin, Desmond J

2015-01-01

Summary Tattooing has long been practised in various societies all around the world and is becoming increasingly common and widespread in the West. Tattoo ink suspensions unquestionably contain pigments composed of nanoparticles, i.e., particles of sub-100 nm dimensions. It is widely acknowledged that nanoparticles have higher levels of chemical activity than their larger particle equivalents. However, assessment of the toxicity of tattoo inks has been the subject of little research and ink manufacturers are not obliged to disclose the exact composition of their products. This study examines tattoo ink particles in two fundamental skin components at the nanometre level. We use atomic force microscopy and light microscopy to examine cryosections of tattooed skin, exploring the collagen fibril networks in the dermis that contain ink nanoparticles. Further, we culture fibroblasts in diluted tattoo ink to explore both the immediate impact of ink pigment on cell viability and also to observe the interaction between particles and the cells. PMID:26171294

High-throughput profiling of nanoparticle-protein interactions by fluorescamine labeling.

PubMed

Ashby, Jonathan; Duan, Yaokai; Ligans, Erik; Tamsi, Michael; Zhong, Wenwan

2015-02-17

A rapid, high throughput fluorescence assay was designed to screen interactions between proteins and nanoparticles. The assay employs fluorescamine, a primary-amine specific fluorogenic dye, to label proteins. Because fluorescamine could specifically target the surface amines on proteins, a conformational change of the protein upon interaction with nanoparticles will result in a change in fluorescence. In the present study, the assay was applied to test the interactions between a selection of proteins and nanoparticles made of polystyrene, silica, or iron oxide. The particles were also different in their hydrodynamic diameter, synthesis procedure, or surface modification. Significant labeling differences were detected when the same protein incubated with different particles. Principal component analysis (PCA) on the collected fluorescence profiles revealed clear grouping effects of the particles based on their properties. The results prove that fluorescamine labeling is capable of detecting protein-nanoparticle interactions, and the resulting fluorescence profile is sensitive to differences in nanoparticle's physical properties. The assay can be carried out in a high-throughput manner, and is rapid with low operation cost. Thus, it is well suited for evaluating interactions between a larger number of proteins and nanoparticles. Such assessment can help to improve our understanding on the molecular basis that governs the biological behaviors of nanomaterials. It will also be useful for initial examination of the bioactivity and reproducibility of nanomaterials employed in biomedical fields.

Depositing α-mangostin nanoparticles to sebaceous gland area for acne treatment.

PubMed

Pan-In, Porntip; Wongsomboon, Atthakorn; Kokpol, Chayada; Chaichanawongsaroj, Nuntaree; Wanichwecharungruang, Supason

2015-12-01

Although entrapment of nanoparticles of appropriate sizes at hair follicles has been clarified, there is no report on specific clinical application of this finding. Since sebaceous gland is associated with hair follicle, we hypothesize that effective acne vulgaris treatment/prevention can be achieved by depositing anti-acne agent in nanoparticle form at the hair follicles. Challenge of this strategy, however, lies at the finding of effective anti-acne particles with minimal skin irritation. Here using cellulose-based nanoparticles as nano-reservoir and α-mangostin (an active component isolated from the edible Garcinia mangostana Linn. fruit) as anti-acne agent, we prepare nanoparticles highly loaded with α-mangostin. Ability of the obtained particles to sustained release α-mangostin into synthetic sebum is demonstrated. The obtained mangostin particles are verified for their insignificant skin irritation through the two-week, twice-daily open application test in 20 healthy human volunteers. Excellent entrapment and sustainment of the mangostin nanoparticles at the hair follicles are elucidated in six human volunteers by detecting the presence of α-mangostin at the roots of hairs pulled from the treated skin area. The 4-week-randomized, double-blind, placebo-controlled, split-face study in 10 acne patients indicates significant improvement in acne vulgaris condition on the side twice daily applied with mangostin nanoparticles. Copyright © 2015 Japanese Pharmacological Society. Production and hosting by Elsevier B.V. All rights reserved.

Labeling TiO2 nanoparticles with dyes for optical fluorescence microscopy and determination of TiO2-DNA nanoconjugate stability.

PubMed

Thurn, Kenneth T; Paunesku, Tatjana; Wu, Aiguo; Brown, Eric M B; Lai, Barry; Vogt, Stefan; Maser, Jörg; Aslam, Mohammed; Dravid, Vinayak; Bergan, Raymond; Woloschak, Gayle E

2009-06-01

Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO2) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO2-DNA nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO2 nanoparticles and TiO2-DNA nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO2 nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO2-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO2-DNA nanoconjugates in malignant cells.

Interaction of PM2.5 airborne particulates with ZnO and TiO2 nanoparticles and their effect on bacteria.

PubMed

Baysal, Asli; Saygin, Hasan; Ustabasi, Gul Sirin

2017-12-21

A significant knowledge gap in nanotechnology is the absence of standardized protocols for examining and comparison the effect of metal oxide nanoparticles on different environment media. Despite the large number of studies on ecotoxicity of nanoparticles, most of them disregard the particles physicochemical transformation under real exposure conditions and interaction with different environmental components like air, soil, water, etc. While one of the main exposure ways is inhalation and/or atmosphere for human and environment, there is no investigation between airborne particulates and nanoparticles. In this study, some metal oxide nanoparticle (ZnO and TiO 2 ) transformation and behavior in PM2.5 air particulate media were examined and evaluated by the influence on nanoparticle physicochemical properties (size, surface charge, surface functionalization) and on bacterium (Gram-positive Bacillus subtilis, Staphylococcus aureus/Gram-negative Escherichia coli, Pseudomonas aeruginosa bacteria) by testing in various concentrations of PM2.5 airborne particulate media to contribute to their environmental hazard and risk assessment in atmosphere. PM2.5 airborne particulate media affected their toxicity and physicochemical properties when compared the results obtained in controlled conditions. ZnO and TiO 2 surfaces were functionalized mainly with sulfoxide groups in PM2.5 air particulates. In addition, tested particles were not observed to be toxic in controlled conditions. However, these were observed inhibition in PM2.5 airborne particulates media by the exposure concentration. These observations and dependence of the bacteria viability ratio explain the importance of particulate matter-nanoparticle interaction.

Specific biomolecule corona is associated with ring-shaped organization of silver nanoparticles in cells

NASA Astrophysics Data System (ADS)

Drescher, Daniela; Guttmann, Peter; Büchner, Tina; Werner, Stephan; Laube, Gregor; Hornemann, Andrea; Tarek, Basel; Schneider, Gerd; Kneipp, Janina

2013-09-01

We correlate the localization of silver nanoparticles inside cells with respect to the cellular architecture with the molecular information in the vicinity of the particle surface by combining nanoscale 3D cryo-soft X-ray tomography (cryo-SXT) with surface-enhanced Raman scattering (SERS). The interaction of the silver nanoparticle surface with small molecules and biopolymers was monitored by SERS in vitro over time in living cells. The spectra indicate a stable, time-independent surface composition of silver nanoparticles, despite the changing environment in the endosomal structure. Cryo-SXT reveals a characteristic ring-shaped organization of the silver nanoparticles in endosomes of different cell types. The ring-like structures inside the endosomes suggest a strong association among silver particles and with membrane structures. The comparison of the data with those obtained with gold nanoparticles suggests that the interactions between the nanoparticles and with the endosomal component are influenced by the molecular composition of the corona.We correlate the localization of silver nanoparticles inside cells with respect to the cellular architecture with the molecular information in the vicinity of the particle surface by combining nanoscale 3D cryo-soft X-ray tomography (cryo-SXT) with surface-enhanced Raman scattering (SERS). The interaction of the silver nanoparticle surface with small molecules and biopolymers was monitored by SERS in vitro over time in living cells. The spectra indicate a stable, time-independent surface composition of silver nanoparticles, despite the changing environment in the endosomal structure. Cryo-SXT reveals a characteristic ring-shaped organization of the silver nanoparticles in endosomes of different cell types. The ring-like structures inside the endosomes suggest a strong association among silver particles and with membrane structures. The comparison of the data with those obtained with gold nanoparticles suggests that the interactions between the nanoparticles and with the endosomal component are influenced by the molecular composition of the corona. Electronic supplementary information (ESI) available: Description of additional experiments. Explanation of transmitted intensity and linear absorption coefficient in a cryo-XRT experiment (Fig. S1 and S2). Additional X-ray data (Fig. S3 and Movie S1). Toxicity of silver nanoparticles (Fig. S4). X-ray microscopy and SERS experiments with gold nanoparticles (Fig. S5 and S6). Size, plasmonic properties, and stability of silver and gold nanoparticles (Fig. S7-S9). Distribution of the silver nanoparticles in the cells using SERS mapping (Fig. S10). Tentative band assignments (Table S1). See DOI: 10.1039/c3nr02129g

Formation of supported lipid bilayers containing phase-segregated domains and their interaction with gold nanoparticles

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

Melby, Eric S.; Mensch, Arielle C.; Lohse, Samuel E.

2016-01-01

The cell membrane represents an important biological interface that nanoparticles may encounter after being released into the environment. Interaction of nanoparticles with cellular membranes may alter membrane structure and function, lead to their uptake into cells, and elicit adverse biological responses. Supported lipid bilayers have proven to be valuable ex vivo models for biological membranes, allowing investigation of their mechanisms of interaction with nanoparticles with a degree of control impossible in living cells. To date, the majority of research on nanoparticle interaction with supported lipid bilayers has employed membranes composed of single or binary mixtures of phospholipids. Cellular membranes containmore » a wide variety of lipids and exhibit lateral organization. Ordered membrane domains enriched in specific membrane components are referred to as lipid rafts and have not been explored with respect to their interaction with nanoparticles. Here we develop model lipid raft-containing membranes amenable to investigation by a variety of surface-sensitive analytical techniques and demonstrate that lipid rafts influence the extent of nanoparticle attachment to model membranes. We determined conditions that allow reliable formation of bilayers containing rafts enriched in sphingomyelin and cholesterol and confirmed their morphology by structured illumination and atomic force microscopies. We demonstrate that lipid rafts increase attachment of cationic gold nanoparticles to model membranes under near physiological ionic strength conditions (0.1 M NaCl) at pH 7.4. We anticipate that these results will serve as the foundation for and motivate further study of nanoparticle interaction with compositionally varied lipid rafts.« less

Individual and collective modes of surface magnetoplasmon in thiolate-protected silver nanoparticles studied by MCD spectroscopy.

PubMed

Yao, Hiroshi; Shiratsu, Taisuke

2016-06-07

Large magneto-optical (MO) responses at the energy of localized surface plasmon resonance (LSPR), namely, surface magnetoplasmons, are demonstrated for the first time in thiolate-protected silver nanoparticles with magnetic circular dichroism (MCD) spectroscopy. The samples examined are decanethiol (DT)-, azobenzenethiol (ABT)-, and ABT/DT mixed-monolayer-protected Ag nanoparticles. ABT-protected Ag nanoparticles are somewhat aggregated and thus exhibit a broad, collective mode of plasmonic absorption, whereas other samples with highly-dispersed nanoparticles show an individual mode of LSPR absorption. In all Ag nanoparticles, a derivative-like MCD signal is observed under an applied magnetic field of 1.6 T, which can be explained in terms of two circular modes of magnetoplasmon caused by the increase (or decrease) in the Lorentz force imparted on the free electrons that oscillate in the left (or right) circular orbits in the nanosphere. For the Ag nanoparticles exhibiting an individual LSPR mode, in particular, simultaneous deconvolution analysis of UV-vis absorption and MCD spectra reveal that (i) the amplitude of the magnetoplasmonic component with lower frequency (ω-), resulting from the reduction in the confinement strength of collective electrons by the Lorentz force, is stronger than that with a higher frequency (ω+); (ii) the accurate shift or cyclotron frequency between two magnetoplasmonic modes (ωc = ω+-ω-) is size-dependent, and presents a very large value with implications for the apparent enhancement of the local magnetic-field in the Ag nanoparticles. These results strongly suggest that the Ag-thiolate layer or Ag-S bonding on the nanoparticle surface plays a significant role in the MO enhancement.

Slowing of Femtosecond Laser-Generated Nanoparticles in a Background Gas

DOE PAGES

Rouleau, Christopher M.; Puretzky, Alexander A.; Geohegan, David B.

2014-11-25

The slowing of Pt nanoparticles in argon background gas was characterized by Rayleigh scattering imaging using a plume of nanoparticles generated by femtosecond laser through thin film ablation (fs-TTFA) of 20 nanometers-thick Pt films. The ablation was performed at threshold laser energy fluences for complete film removal to provide a well-defined plume consisting almost entirely of nanoparticles traveling with a narrow velocity distribution, providing a unique system to unambiguously characterize the slowing of nanoparticles during interaction with background gases. Nanoparticles of ~200 nm diameter were found to decelerate in background Ar gas with pressures less than 50 Torr in goodmore » agreement with a linear drag model in the Epstein regime. Based on this model, the stopping distance of small nanoparticles in the plume was predicted and tested by particle collection in an off-axis geometry, and size distribution analysis by transmission electron microscopy. These results permit a basis to interpret nanoparticle propagation through background gases in laser ablation plumes that contain mixed components.« less

Biosynthesis of silver nanoparticles using lemon leaves extract and its application for antimicrobial finish on fabric

NASA Astrophysics Data System (ADS)

Vankar, Padma S.; Shukla, Dhara

2012-06-01

Preparation of silver nanoparticles have been carried out using aqueous extract of lemon leaves ( Citrus limon) which acts as reducing agent and encapsulating cage for the silver nanoparticles. These silver nanoparticles have been used for durable textile finish on cotton and silk fabrics. Remarkable antifungal activity has been observed in the treated fabrics. The antimicrobial activity of silver nanoparticles derived from lemon leaves showed enhancement in activity due to synergistic effect of silver and essential oil components of lemon leaves. The present investigation shows the extracellular synthesis of highly stable silver nanoparticles by biotransformation using the extract of lemon leaves by controlled reduction of the Ag+ ion to Ag0. Further the silver nanoparticles were used for antifungal treatment of fabrics which was tested by antifungal activity assessment of textile material by Agar diffusion method against Fusarium oxysporum and Alternaria brassicicola. Formation of the metallic nanoparticles was established by FT-IR, UV-Visible spectroscopy, transmission electron microscopy, scanning electron microscopy, atomic force microscopy.

Evaporation of sessile droplets affected by graphite nanoparticles and binary base fluids.

PubMed

Zhong, Xin; Duan, Fei

2014-11-26

The effects of ethanol component and nanoparticle concentration on evaporation dynamics of graphite-water nanofluid droplets have been studied experimentally. The results show that the formed deposition patterns vary greatly with an increase in ethanol concentration from 0 to 50 vol %. Nanoparticles have been observed to be carried to the droplet surface and form a large piece of aggregate. The volume evaporation rate on average increases as the ethanol concentration increases from 0 to 50 vol % in the binary mixture nanofluid droplets. The evaporation rate at the initial stage is more rapid than that at the late stage to dry, revealing a deviation from a linear fitting line, standing for a constant evaporation rate. The deviation is more intense with a higher ethanol concentration. The ethanol-induced smaller liquid-vapor surface tension leads to higher wettability of the nanofluid droplets. The graphite nanoparticles in ethanol-water droplets reinforce the pinning effect in the drying process, and the droplets with more ethanol demonstrate the depinning behavior only at the late stage. The addition of graphite nanoparticles in water enhances a droplet baseline spreading at the beginning of evaporation, a pinning effect during evaporation, and the evaporation rate. However, with a relatively high nanoparticle concentration, the enhancement is attenuated.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques†

PubMed Central

Plascencia-Villa, Germán; Starr, Clarise R.; Armstrong, Linda S.; Ponce, Arturo

2016-01-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO2, TiO2 and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO2 and TiO2, whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution. PMID:23023106

The Intracellular Destiny of the Protein Corona: A Study on its Cellular Internalization and Evolution.

PubMed

Bertoli, Filippo; Garry, David; Monopoli, Marco P; Salvati, Anna; Dawson, Kenneth A

2016-11-22

It has been well established that the early stages of nanoparticle-cell interactions are governed, at least in part, by the layer of proteins and other biomolecules adsorbed and slowly exchanged with the surrounding biological media (biomolecular corona). Subsequent to membrane interactions, nanoparticles are typically internalized into the cell and trafficked along defined pathways such as, in many cases, the endolysosomal pathway. Indeed, if the original corona is partially retained on the nanoparticle surface, the biomolecules in this layer may play an important role in determining subsequent cellular processing. In this work, using a combination of organelle separation and fluorescence labeling of the initial extracellular corona, we clarify its intracellular evolution as nanoparticles travel within the cell. We show that specific proteins present in the original protein corona are retained on the nanoparticles until they accumulate in lysosomes, and, once there, they are degraded. We also report on how different bare surfaces (amino and carboxyl modified) affect the details of this evolution. One overarching discovery is that the same serum proteins can exhibit different intracellular processing when carried inside cells by nanoparticles, as components of their corona, compared to what is observed when they are transported freely from the extracellular medium.

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.

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.

The morphological changes in lymphoid organs and peripheral blood indicators in rats after peroral administration of gold nanoparticles

NASA Astrophysics Data System (ADS)

Bucharskaya, A. B.; Pakhomy, S. S.; Zlobina, O. V.; Maslyakova, G. N.; Matveeva, O. V.; Bugaeva, I. O.; Navolokin, N. A.; Khlebtsov, B. N.; Bogatyrev, V. A.; Khlebtsov, N. G.; Tuchin, V. V.

2016-03-01

The wide application of nanotechnologies in medicine requires the careful study of various aspects of their potential safety. The effects of prolonged peroral administration of gold nanoparticles on morphological changes in lymphoid organs and indicators of peripheral blood of laboratory animals were investigated in experiment. The gold nanospheres functionalized with thiolated polyethylene glycol sizes 2, 15 and 50 nm were administered orally for 15 days to outbred white rats at a dosage of 190 μg/kg of animal body weight. The standard histological and hematological staining were used for morphological study of lymphoid organs and bone marrow smears. The size-dependent decrease of the number of neutrophils and lymphocytes was noted in the study of peripheral blood, especially pronounced after administration of gold nanoparticles with size of 50 nm. The stimulation of myelocytic germ of hematopoiesis was recorded at morphological study of the bone marrow. The signs of strengthening of the processes of differentiation and maturation of cellular elements were found in lymph nodes, which were showed as the increasing number of immunoblasts and large lymphocytes. The quantitative changes of cellular component morphology of lymphoid organs due to activation of migration, proliferation and differentiation of immune cells indicate the presence of immunostimulation effect of gold nanoparticles.

Optical and electrical properties of composites based on functional components of an electroluminescent layer

NASA Astrophysics Data System (ADS)

Avanesyan, V. T.; Rakina, A. V.; Sychov, M. M.; Vasina, E. S.

2016-07-01

Optical and electrical properties of cyanoethyl ether of polyvinyl alcohol with filling of barium titanate BaTiO3 modified by shungite carbon nanoparticles are studied. It is found that the modification affects the diffuse reflectance spectra and dispersion characteristics of the impedance components due to a change in the nature of interfacial interactions in the system. The values of the forbidden band width for various modifier and filler concentrations are determined.

Unveiling the in Vivo Protein Corona of Circulating Leukocyte-like Carriers.

PubMed

Corbo, Claudia; Molinaro, Roberto; Taraballi, Francesca; Toledano Furman, Naama E; Hartman, Kelly A; Sherman, Michael B; De Rosa, Enrica; Kirui, Dickson K; Salvatore, Francesco; Tasciotti, Ennio

2017-03-28

Understanding interactions occurring at the interface between nanoparticles and biological components is an urgent challenge in nanomedicine due to their effect on the biological fate of nanoparticles. After the systemic injection of nanoparticles, a protein corona constructed by blood components surrounds the carrier's surface and modulates its pharmacokinetics and biodistribution. Biomimicry-based approaches in nanotechnology attempt to imitate what happens in nature in order to transfer specific natural functionalities to synthetic nanoparticles. Several biomimetic formulations have been developed, showing superior in vivo features as a result of their cell-like identity. We have recently designed biomimetic liposomes, called leukosomes, which recapitulate the ability of leukocytes to target inflamed endothelium and escape clearance by the immune system. To gain insight into the properties of leukosomes, we decided to investigate their protein corona in vivo. So far, most information about the protein corona has been obtained using in vitro experiments, which have been shown to minimally reproduce in vivo phenomena. Here we directly show a time-dependent quantitative and qualitative analysis of the protein corona adsorbed in vivo on leukosomes and control liposomes. We observed that leukosomes absorb fewer proteins than liposomes, and we identified a group of proteins specifically adsorbed on leukosomes. Moreover, we hypothesize that the presence of macrophage receptors on leukosomes' surface neutralizes their protein corona-meditated uptake by immune cells. This work unveils the protein corona of a biomimetic carrier and is one of the few studies on the corona performed in vivo.

Design and Fabrication of Multifunctional Sericin Nanoparticles for Tumor Targeting and pH-Responsive Subcellular Delivery of Cancer Chemotherapy Drugs.

PubMed

Huang, Lei; Tao, Kaixiong; Liu, Jia; Qi, Chao; Xu, Luming; Chang, Panpan; Gao, Jinbo; Shuai, Xiaoming; Wang, Guobin; Wang, Zheng; Wang, Lin

2016-03-01

The severe cytotoxicity of cancer chemotherapy drugs limits their clinical applications. Various protein-based nanoparticles with good biocompatibility have been developed for chemotherapy drug delivery in hope of reducing drugs' side effects. Sericin, a natural protein from silk, has no immunogenicity and possesses diverse bioactivities that have prompted sericin's application studies. However, the potential of sericin as a multifunctional nanoscale vehicle for cancer therapy have not been fully explored. Here we report the successful fabrication and characterization of folate-conjugated sericin nanoparticles with cancer-targeting capability for pH-responsive release of doxorubicin (these nanoparticles are termed "FA-SND"). DOX is covalently linked to sericin through pH-sensitive hydrazone bonds that render a pH-triggered release property. The hydrophobicity of DOX and the hydrophilicity of sericin promote the self-assembly of sericin-DOX (SND) nanoconjugates. Folate (FA) is then covalently grafted to SND nanoconjugates as a binding unit for actively targeting cancer cells that overexpress folate receptors. Our characterization study shows that FA-SND nanoparticles exhibit negative surface charges that would reduce nonspecific clearance by circulation. These nanoparticles possess good cytotoxicity and hemocompatibiliy. Acidic environment (pH 5.0) triggers effective DOX release from FA-SND, 5-fold higher than does a neutral condition (pH 7.4). Further, FA-SND nanoparticles specifically target folate-receptor-rich KB cells, and endocytosed into lysosomes, an acidic organelle. The acidic microenvironment of lysosomes promotes a rapid release of DOX to nuclei, producing cancer specific chemo-cytotoxicity. Thus, FA-mediated cancer targeting and lysosomal-acidity promoting DOX release, two sequentially-occurring cellular events triggered by the designed components of FA-SND, form the basis for FA-SND to achieve its localized and intracellular chemo-cytotoxicity. Together, this study suggests that these FA-SND nanoparticles may be a potentially effective carrier particularly useful for delivering hydrophobic chemotherapeutic agents for treating cancers with high-level expression of folate receptors.

Organic/hybrid nanoparticles and single-walled carbon nanotubes: preparation methods and chiral applications.

PubMed

Alhassen, Haysem; Antony, Vijy; Ghanem, Ashraf; Yajadda, Mir Massoud Aghili; Han, Zhao Jun; Ostrikov, Kostya Ken

2014-11-01

Nanoparticles are molecular-sized solids with at least one dimension measuring between 1-100 nm or 10-1000 nm depending on the individual discipline's perspective. They are aggregates of anywhere from a few hundreds to tens of thousands of atoms which render them larger than molecules but smaller than bulk solids. Consequently, they frequently exhibit physical and chemical properties somewhere between. On the other hand, nanocrystals are a special class of nanoparticles which have started gaining attention recently owing to their unique crystalline structures which provide a larger surface area and promising applications including chiral separations. Hybrid nanoparticles are supported by the growing interest of chemists, physicists, and biologists, who are researching to fully exploit them. These materials can be defined as molecular or nano-composites with mixed (organic or bio) and inorganic components, where at least one of the component domain has a dimension ranging from a few Å to several nanometers. Similarly, and due to their extraordinary physical, chemical, and electrical properties, single-walled carbon nanotubes have been the subject of intense research. In this short review, the focus is mainly on the current well-established simple preparation techniques of chiral organic and hybrid nanoparticles as well as single-walled carbon nanotubes and their applications in separation science. Of particular interest, cinchonidine, chitosan, and β-CD-modified gold nanoparticles (GNPs) are discussed as model examples for organic and hybrid nanoparticles. Likewise, the chemical vapor deposition method, used in the preparation of single-walled carbon nanotubes, is discussed. The enantioseparation applications of these model nanomaterials is also presented. © 2014 Wiley Periodicals, Inc.

Spreading of nanofluids driven by the structural disjoining pressure gradient.

PubMed

Chengara, Anoop; Nikolov, Alex D; Wasan, Darsh T; Trokhymchuk, Andrij; Henderson, Douglas

2004-12-01

This paper discusses the role of the structural disjoining pressure exerted by nanoparticles on the spreading of a liquid film containing these particles. The origin of the structural disjoining pressure in a confined geometry is due to the layering of the particles normal to the confining plane and has already been traced to the net increase in the entropy of the system in previous studies. In a recent paper, Wasan and Nikolov (Nature, 423 (2003) 156) pointed out that the structural component of the disjoining pressure is strong enough to move a liquid wedge; this casts a new light on many applications-most notably, detergency. While the concept of spreading driven by the disjoining pressure is not new, the importance of the structural disjoining pressure arises from its long-range nature (as compared to the van der Waals' force), making it an important component of the overall force balance near the contact line. In this paper, we report on a parametric study of the spreading phenomena by examining the effects of nanoparticle size, concentration and polydispersity on the displacement of an oil-aqueous interface with the aqueous bulk containing nanoparticles. The solution of the extended Laplace-Young equations for the profile of the meniscus yields the position of the nominal contact line under the action of the structural disjoining pressure. Simulations show that the displacement of the contact line is greater with a high nanoparticle volume fraction, small particles for the same volume fraction, monodispersed (in size) particles rather than polydispersed particles and when the resisting capillary pressure is small, i.e., when the interfacial tension is low and/or the radius of the dispersed phase drop/bubble is large.

Synthesis of Au@polymer nanohybrids with transited core-shell morphology from concentric to eccentric Emoji-N or Janus nanoparticles.

PubMed

Guarrotxena, Nekane; García, Olga; Quijada-Garrido, Isabel

2018-04-10

The combination of multifunctionality and synergestic effect displayed by hybrid nanoparticles (NPs) has been revealed as an effective stratagem in the development of advanced nanostructures with unique biotechnology and optoelectronic applications. Although important work has been devoted, the demand of facile, versatile and efficient synthetic approach remains still challenging. Herein, we report a feasible and innovative way for polymer-shell assembling onto gold nanoparticles in competitive conditions of hydrophobic/hydrophilic feature and interfacial energy of components to generate core-shell nanohybrids with singular morphologies. The fine control of reaction parameters allows a modulated transformation from concentric to eccentric nanostructure-geometries. In this regard, a rational selection of the components and solvent ratio guarantee the reproducibility and efficiency on hybrid-nanoassembly. Furthermore, the simplicity of the synthetic approach offers the possibility to obtain asymmetric Janus NPs and new morphologies (quizzical-aspheric polymer-shell, named Emoji-N-hybrids) with adjustable surface-coating, leading to new properties and applications that are unavailable to their symmetrical or single components.

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.

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

In Vitro Assessment of Nanoparticle Effects on Blood Coagulation.

PubMed

Potter, Timothy M; Rodriguez, Jamie C; Neun, Barry W; Ilinskaya, Anna N; Cedrone, Edward; Dobrovolskaia, Marina A

2018-01-01

Blood clotting is a complex process which involves both cellular and biochemical components. The key cellular players in the blood clotting process are thrombocytes or platelets. Other cells, including leukocytes and endothelial cells, contribute to clotting by expressing the so-called pro-coagulant activity (PCA) complex on their surface. The biochemical component of blood clotting is represented by the plasma coagulation cascade, which includes plasma proteins also known as coagulation factors. The coordinated interaction between platelets, leukocytes, endothelial cells, and plasma coagulation factors is necessary for maintaining hemostasis and for preventing excessive bleeding. Undesirable activation of all or some of these components may lead to pathological blood coagulation and life-threatening conditions such as consumptive coagulopathy or disseminated intravascular coagulation (DIC). In contrast, unintended inhibition of the coagulation pathways may lead to hemorrhage. Thrombogenicity is the property of a test material to induce blood coagulation by affecting one or more elements of the clotting process. Anticoagulant activity refers to the property of a test material to inhibit coagulation. The tendency to cause platelet aggregation, perturb plasma coagulation, and induce leukocyte PCA can serve as an in vitro measure of a nanomaterial's likelihood to be pro- or anticoagulant in vivo. This chapter describes three procedures for in vitro analyses of platelet aggregation, plasma coagulation time, and activation of leukocyte PCA. Platelet aggregation and plasma coagulation procedures have been described earlier. The revision here includes updated details about nanoparticle sample preparation, selection of nanoparticle concentration for the in vitro study, and updated details about assay controls. The chapter is expanded to describe a method for the leukocyte PCA analysis and case studies demonstrating the performance of these in vitro assays.

Potential phototoxicity of aged Al(OH)3-coated Ti02 nanoparticles in retinal pigment epithelial cells

EPA Science Inventory

Titanium dioxide (TiO2) nanoparticles (NPs) exposed to UVA radiation generate reactive oxygen species (ROS). As a component of sunscreen formulations, TiO2 NPs may be coated with Al(OH)3 to prevent ROS from causing oxidative damage to tissues. Simulated swimming pool water (SSPW)...

Elongated Nanoparticle Aggregates in Cancer Cells for Mechanical Destruction with Low Frequency Rotating Magnetic Field.

PubMed

Shen, Yajing; Wu, Congyu; Uyeda, Taro Q P; Plaza, Gustavo R; Liu, Bin; Han, Yu; Lesniak, Maciej S; Cheng, Yu

2017-01-01

Magnetic nanoparticles (MNPs) functionalized with targeting moieties can recognize specific cell components and induce mechanical actuation under magnetic field. Their size is adequate for reaching tumors and targeting cancer cells. However, due to the nanometric size, the force generated by MNPs is smaller than the force required for largely disrupting key components of cells. Here, we show the magnetic assembly process of the nanoparticles inside the cells, to form elongated aggregates with the size required to produce elevated mechanical forces. We synthesized iron oxide nanoparticles doped with zinc, to obtain high magnetization, and functionalized with the epidermal growth factor (EGF) peptide for targeting cancer cells. Under a low frequency rotating magnetic field at 15 Hz and 40 mT, the internalized EGF-MNPs formed elongated aggregates and generated hundreds of pN to dramatically damage the plasma and lysosomal membranes. The physical disruption, including leakage of lysosomal hydrolases into the cytosol, led to programmed cell death and necrosis. Our work provides a novel strategy of designing magnetic nanomedicines for mechanical destruction of cancer cells.

Development of device for quantifying magnetic nanoparticle tracers accumulating in sentinel lymph nodes

NASA Astrophysics Data System (ADS)

Kuwahata, Akihiro; Kaneko, Miki; Chikaki, Shinichi; Kusakabe, Moriaki; Sekino, Masaki

2018-05-01

The developed device with electromagnetic coils and small permanent magnets quantifies the iron contents of superparamagnetic iron oxide nanoparticles for sentinel lymph node (SLN) biopsy. To remove diamagnetic and paramagnetic components and detect only superparamagnetic components, a 2nd harmonics signal is detected by a gradiometer under a moderate AC magnetic field (1-2 mT) with the fundamental frequency (2.944 kHz) of the coils and DC magnetic field (1-2 mT) of the magnets. The detection limit with a signal-to-noise ratio of 5 is approximately 0.28 μg of iron, and the device has a wide dynamic range of 104, 0.28 μg-2.8 mg. Additional coils and permanent magnets play an important role producing the optimum distribution of AC/DC magnetic fields for an iron distribution-independent and SLN size-independent quantification. We demonstrated the quantification of the iron in phantoms, which have a size of 3-20 mm with varied iron distributions and contain magnetic nanoparticles numerically. These results indicate that the developed device is useful for quantifying the magnetic nanoparticles accumulating in SLNs.

Elongated Nanoparticle Aggregates in Cancer Cells for Mechanical Destruction with Low Frequency Rotating Magnetic Field

PubMed Central

Shen, Yajing; Wu, Congyu; Uyeda, Taro Q. P.; Plaza, Gustavo R.; Liu, Bin; Han, Yu; Lesniak, Maciej S.; Cheng, Yu

2017-01-01

Magnetic nanoparticles (MNPs) functionalized with targeting moieties can recognize specific cell components and induce mechanical actuation under magnetic field. Their size is adequate for reaching tumors and targeting cancer cells. However, due to the nanometric size, the force generated by MNPs is smaller than the force required for largely disrupting key components of cells. Here, we show the magnetic assembly process of the nanoparticles inside the cells, to form elongated aggregates with the size required to produce elevated mechanical forces. We synthesized iron oxide nanoparticles doped with zinc, to obtain high magnetization, and functionalized with the epidermal growth factor (EGF) peptide for targeting cancer cells. Under a low frequency rotating magnetic field at 15 Hz and 40 mT, the internalized EGF-MNPs formed elongated aggregates and generated hundreds of pN to dramatically damage the plasma and lysosomal membranes. The physical disruption, including leakage of lysosomal hydrolases into the cytosol, led to programmed cell death and necrosis. Our work provides a novel strategy of designing magnetic nanomedicines for mechanical destruction of cancer cells. PMID:28529648

Complement proteins bind to nanoparticle protein corona and undergo dynamic exchange in vivo

NASA Astrophysics Data System (ADS)

Chen, Fangfang; Wang, Guankui; Griffin, James I.; Brenneman, Barbara; Banda, Nirmal K.; Holers, V. Michael; Backos, Donald S.; Wu, Linping; Moghimi, Seyed Moein; Simberg, Dmitri

2017-05-01

When nanoparticles are intravenously injected into the body, complement proteins deposit on the surface of nanoparticles in a process called opsonization. These proteins prime the particle for removal by immune cells and may contribute toward infusion-related adverse effects such as allergic responses. The ways complement proteins assemble on nanoparticles have remained unclear. Here, we show that dextran-coated superparamagnetic iron oxide core-shell nanoworms incubated in human serum and plasma are rapidly opsonized with the third complement component (C3) via the alternative pathway. Serum and plasma proteins bound to the nanoworms are mostly intercalated into the nanoworm shell. We show that C3 covalently binds to these absorbed proteins rather than the dextran shell and the protein-bound C3 undergoes dynamic exchange in vitro. Surface-bound proteins accelerate the assembly of the complement components of the alternative pathway on the nanoworm surface. When nanoworms pre-coated with human plasma were injected into mice, C3 and other adsorbed proteins undergo rapid loss. Our results provide important insight into dynamics of protein adsorption and complement opsonization of nanomedicines.

Ultrafast transient absorption studies of hematite nanoparticles: the effect of particle shape on exciton dynamics.

PubMed

Fitzmorris, Bob C; Patete, Jonathan M; Smith, Jacqueline; Mascorro, Xiomara; Adams, Staci; Wong, Stanislaus S; Zhang, Jin Z

2013-10-01

Much progress has been made in using hematite (α-Fe2 O3 ) as a potentially practical and sustainable material for applications such as solar-energy conversion and photoelectrochemical (PEC) water splitting; however, recent studies have shown that the performance can be limited by a very short charge-carrier diffusion length or exciton lifetime. In this study, we performed ultrafast studies on hematite nanoparticles of different shapes to determine the possible influence of particle shape on the exciton dynamics. Nanorice, multifaceted spheroidal nanoparticles, faceted nanocubes, and faceted nanorhombohedra were synthesized and characterized by using SEM and XRD techniques. Their exciton dynamics were investigated by using femtosecond transient absorption (TA) spectroscopy. Although the TA spectral features differ for the four samples studied, their decay profiles are similar, which can be fitted with time constants of 1-3 ps, approximately 25 ps, and a slow nanosecond component extending beyond the experimental time window that was measured (2 ns). The results indicate that the overall exciton lifetime is weakly dependent on the shape of the hematite nanoparticles, even though the overall optical absorption and scattering are influenced by the particle shape. This study suggests that other strategies need to be developed to increase the exciton lifetime or to lengthen the exciton diffusion length in hematite nanostructures. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Specifically Formed Corona on Silica Nanoparticles Enhances Transforming Growth Factor β1 Activity in Triggering Lung Fibrosis.

PubMed

Wang, Zhenzhen; Wang, Chunming; Liu, Shang; He, Wei; Wang, Lintao; Gan, JingJing; Huang, Zhen; Wang, Zhenheng; Wei, Haoyang; Zhang, Junfeng; Dong, Lei

2017-02-28

A corona is a layer of macromolecules formed on a nanoparticle surface in vivo. It can substantially change the biological identity of nanomaterials and possibly trigger adverse responses from the body tissues. Dissecting the role of the corona in the development of a particular disease may provide profound insights for understanding toxicity of nanomaterials in general. In our present study, we explored the capability of different silica nanoparticles (SiNPs) to induce silicosis in the mouse lung and analyzed the composition of coronas formed on these particles. We found that SiNPs of certain size and surface chemistry could specifically recruit transforming growth factor β1 (TGF-β1) into their corona, which subsequently induces the development of lung fibrosis. Once embedded into the corona on SiNPs, TGF-β1 was remarkably more stable than in its free form, and its fibrosis-triggering activity was significantly prolonged. Our study meaningfully demonstrates that a specific corona component on a certain nanoparticle could initiate a particular pathogenic process in a clinically relevant disease model. Our findings may shed light on the understanding of molecular mechanisms of human health risks correlated with exposure to small-scale substances.

Study of interaction of GNR with glioblastoma cells

NASA Astrophysics Data System (ADS)

Hole, Arti; Cardoso-Avila, P. E.; Sridharan, Sangita; Sahu, Aditi; Nair, Jyothi; Dongre, Harsh; Goda, Jayant S.; Sawant, Sharada; Dutt, Shilpee; Pichardo-Molina, J. L.; Murali Krishna, C.

2018-01-01

Radiation resistance is one of the major causes of recurrence and failure of radiotherapy. Different methods have been used to increase the efficacy of radiation therapy and at the same time restrict the radiation resistivity. From last few years nanoparticles have played a key role in the enhancement of radiosensitization. The densely packed nanoparticles can selectively scatter or absorb the high radiations, which allow better targeting of cellular components within the tumor hence resulting in increased radiation damage to the cancer cells. Glioblastoma multiforme (GBM) is one of the highly radioresistant brain cancer. Current treatment methods are surgical resection followed by concurrent chemo and radiation therapy. In this study we have used in-house engineered gold nano rodes (GNR) and analyzed their effect on U-87MG cell lines. MTT assay was employed to determine the cytotoxic concentration of the nanoparticles. Raman spectroscopy was used to analyze the effect of gold nanoparticles on glioma cells, which was followed by transmission electron microscopic examinations to visualize their cellular penetration. Our data shows that GNR were able to penetrate the cells and induce cytotoxicity at the concentration of 198 μM as determined by MTT assay at 24 post GNP treatment. Additionally, we show that Raman spectroscopy, could classify spectra between untreated and cells treated with nanoparticles. Taken together, this study shows GNR penetration and cytotoxicity in glioma cells thereby providing a rationale to use them in cancer therapeutics. Future studies will be carried out to study the biological activity of the formulation as a radiosensitizer in GBM.

Targeting Cancer with Antisense Oligomers

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

Hnatowich, DJ

With financial assistance from the Department of Energy, we have shown definitively that radiolabeled antisense DNAs and other oligomers will accumulate in target cancer cells in vitro and in vivo by an antisense mechanism. We have also shown that the number of mRNA targets for our antisense oligomers in the cancer cell types that we have investigated so far is sufficient to provide and antisense image and/or radiotherapy of cancer in mice. These studies have been reported in about 10 publications. However our observation over the past several years has shown that radiolabeled antisense oligomers administered intravenously in their nativemore » and naked form will accumulate and be retained in target xenografts by an antisense mechanism but will also accumulate at high levels in normal organs such as liver, spleen and kidneys. We have investigated unsuccessfully several commercially available vectors. Thus the use of radiolabeled antisense oligomers for the imaging of cancer must await novel approaches to delivery. This laboratory has therefore pursued two new paths, optical imaging of tumor and Auger radiotherapy. We are developing a novel method of optical imaging tumor using antisense oligomers with a fluorophore is administered while hybridized with a shorter complementary oligomer with an inhibitor. In culture and in tumored mice that the duplex remains intact and thus nonfluorescent until it encounters its target mRNA at which time it dissociates and the antisense oligomer binds along with its fluorophore to the target. Simultaneous with the above, we have also observed, as have others, that antisense oligomers migrate rapidly and quantitatively to the nucleus upon crossing cell membranes. The Auger electron radiotherapy path results from this observation since the nuclear migration properties could be used effectively to bring and to retain in the nucleus an Auger emitting radionuclide such as 111In or 125I bound to the antisense oligomer. Since the object becomes radiotherapy rather than imaging, the delivery problem may be obviated by attaching the antisense oligomer to an antitumor antibody to improve delivery following intravenous administration. Since many antibodies are trapped in endosomes following internalization, a cell penetrating peptide such as tat will also be included to ensure transport of the complex without entrapment. Rather than covalent conjugation of the three entities, we are using streptavidin as linker after biotinylated each component. Our recent efforts have concentrated on establishing the influence of the streptavidin linker on the properties of each component within the delivery nanoparticle. Thus, we have shown that the Herceptin antibody, when linked to a labeled oligomer via streptavidin, remains capable of directing the label oligomer to Her2+ tumor cells in vitro and Her2+ tumor xenografts in mice. In addition, we have demonstrated that a labeled antisense oligomer within the nanoparticle remains capable of migrating to the nucleus and binding to its target mRNA in vitro and in vivo. We have shown that the tat peptide also preserves its properties of cell transport when incubated as one component of the nanoparticle. Most recently, we have addressed another of our concerns, namely whether the streptavidin would adversely effect the biodistribution of the antisense oligomer. We were pleased to find that the 99mTc-labeled antisense MORF within the Herceptin three component and two component nanoparticles accumulated and was retained in tumor in a manner suggestive of radiolabeled Herceptin itself. Thus the preserved properties within the streptavidin delivery nanoparticle of the Herceptin antibody, the tat peptide and the 111In labeled antisense MORF oligomer will explain why we have successfully demonstrated an Auger electron-mediated, antisense-mediated radiotherapy in cells in culture. One remaining concern is that the delivery nanoparticle may deliver the Auger electron emitting radionuclide to the nucleus of normal cells as well as tumor cells. We have now performed tumored mice studies of the three component delivery nanoparticle with the antisense MORF labeled with Cy3 so that tissue slices could be examined by immunohistology for evidence of MORF accumulations in the nuclei of both tumor and normal tissues. Microscopic examination shows nuclear staining in approximately 20% of the tumor cells in animals injected with the antisense nanoparticle and 10% of the tumor cells in animals receiving the sense nanoparticle, whereas no nuclear staining is seen in the tumor cells of mice given the PBS injection as another control. No nuclear staining was observed in all sections from all normal organs. Finally, my colleagues and I wish to express our gratitude to the DOE for their generous support of our research at a time when the NIH was unwilling to fund what they believed to be a risky« less

Nanosized iron and chromium oxides supported on mesoporous CeO2 and SBA-15 silica: Physicochemical and catalytic study

NASA Astrophysics Data System (ADS)

Tsoncheva, Tanya; Roggenbuck, Jan; Paneva, Daniela; Dimitrov, Momtchil; Mitov, Ivan; Fröba, Michael

2010-11-01

Mesoporous ceria and SBA-15 silica were modified with iron and chromium oxide nanoparticles and characterized by XRD, N2-physisorption, FTIR, UV-vis, Moessbauer spectroscopy and TPR-TG in hydrogen. Their catalytic behaviour in methanol decomposition to CO and hydrogen was also studied. Stabilization of mono- and bi-chromate species, FeOx patches or isolated iron ions as well as Fe2O3 and Cr2O3 nanoparticles in different ratio depending on the nature of the porous matrix was observed. The simultaneous presence of iron and chromium oxides lead to change in their dispersion, providing easier reducibility, higher catalytic activity and stability of the obtained materials in comparison with the corresponding mono-component ones. The "intimate contact" at the interface of both loaded metal oxide nanoparticles and the support was discussed with respect to explain the differences in the state of the active ingredient and its specific catalytic behaviour.

Cell Membrane-formed Nanovesicles for Disease-Targeted Delivery

PubMed Central

Gao, Jin; Chu, Dafeng; Wang, Zhenjia

2016-01-01

Vascular inflammation is underlying components of most diseases. To target inflamed vasculature, nanoparticles are commonly engineered by conjugating antibody to the nanoparticle surface, but this bottom-up approach could affect nanoparticle targeting and therapeutic efficacy in complex, physiologically related systems. During vascular inflammation endothelium via the NF-κB pathway instantly upregulates intercellular adhesion molecule 1 (ICAM-1) which binds integrin β2 on neutrophil membrane. Inspired by this interaction, we created a nanovesicle-based drug delivery system using nitrogen cavitation which rapidly disrupts activated neutrophils to make cell membrane nanovesicles. Studies using intravital microscopy of live mouse cremaster venules showed that these vesicles can selectively bind inflamed vasculature because they possess intact targeting molecules of integrin β2. Administering of nanovesicles loaded with TPCA-1 (a NF-κB inhibitor) markedly mitigated mouse acute lung inflammation. Our studies reveal a new top-down strategy for directly employing a diseased tissue to produce biofunctional nanovesicle-based drug delivery systems potentially applied to treat various diseases. PMID:26778696

Comprehensive investigation of noble metal nanoparticles shape, size and material on the optical response of optimal plasmonic Y-splitter waveguides

NASA Astrophysics Data System (ADS)

Ahmadivand, Arash; Golmohammadi, Saeed

2014-01-01

With the purpose of guiding and splitting of optical power at C-band spectrum, we studied Y-shape splitters based on various shapes of nanoparticles as a plasmon waveguide. We applied different configurations of Gold (Au) and Silver (Ag) nanoparticles including spheres, rods and rings, to optimize the efficiency and losses of two and four-branch splitters. The best performance in light transportation specifically at telecom wavelength (λ≈1550 nm) is achieved by nanorings, due to an extra degree of freedom in their geometrical components. In addition, comparisons of several values for offset distance (doffset) of examined structures shows that Au nanoring splitters with feasible lower doffset have high quality in guiding and splitting of light through the structure. Finally, we studied four-branch Y-splitters based on Au and Ag nanorings with least possible offset distances to optimize the splitter performance. The power transmission as a key element is calculated for examined structures.

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

DOE PAGES

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien; ...

2017-05-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

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

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Supra-Nanoparticle Functional Assemblies through Programmable Stacking.

PubMed

Tian, Cheng; Cordeiro, Marco Aurelio L; Lhermitte, Julien; Xin, Huolin L; Shani, Lior; Liu, Mingzhao; Ma, Chunli; Yeshurun, Yosef; DiMarzio, Donald; Gang, Oleg

2017-07-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. Here, we report a general method of assembling nanoparticles in a linear "pillar" morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization. By controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.

Silver Nanoparticle Oligonucleotide Conjugates Based on DNA with Triple Cyclic Disulfide Moieties

PubMed Central

Lee, Jae-Seung; Lytton-Jean, Abigail K. R.; Hurst, Sarah J.; Mirkin, Chad A.

2011-01-01

We report a new strategy for preparing silver nanoparticle oligonucleotide conjugates that are based upon DNA with cyclic disulfide-anchoring groups. These particles are extremely stable and can withstand NaCl concentrations up to 1.0 M. When silver nanoparticles functionalized with complementary sequences are combined, they assemble to form DNA-linked nanoparticle networks. This assembly process is reversible with heating and is associated with a red-shifting of the particle surface plasmon resonance and a concomitant color change from yellow to pale red. Analogous to the oligonucleotide-functionalized gold nanoparticles, these particles also exhibit highly cooperative binding properties with extremely sharp melting transitions. This work is an important step towards being able to use silver nanoparticle oligonucleotide conjugates for a variety of purposes, including molecular diagnostic labels, synthons in programmable materials synthesis approaches, and functional components for nanoelectronic and plasmonic devices. PMID:17571909

Researches on Tie Rod Ends Lubricated by Grease with TiO2 and ZrO2 Nanoparticles

NASA Astrophysics Data System (ADS)

Wozniak, Marek; Siczek, Krzysztof; Kubiak, Przemysław; Jozwiak, Piotr; Siczek, Krystian

2018-05-01

The nanoparticles of some materials can be used successfully to improve tribological properties through decreasing both wear and friction borne out of contact between the contact surfaces of elements in different devices, particularly vehicles. Nanoparticles of TiO2 and ZrO2 were chosen as additives to the lithium grease lubricating the contact surfaces in tie rod ends. The object of study was the steel ball – the component of the tie rod end – mating with the polymer insert and lubricated with the pure lithium grease or containing the addition of pure TiO2, pure ZrO2 nanoparticles, with a 1%wt. Studies on friction were carried out using the tester allowing cyclical rotational motion and different loading of contact. Wear was investigated by driving a car, whose tie rod ends were analysed, on a fixed ‘eight’-shape track and with a fixed velocity pattern. The aim of the study was to obtain the values and waveforms of friction moment and wear versus cycles, loading and composition of lubricating grease. The waveforms of friction coefficient were obtained using the FEM model of the analysed contact zone. Based on the obtained waveforms, recommendations for the composition of additives for lithium grease were made.

MesoDyn simulation study on the phase morphologies of Miktoarm PEO-b-PMMA copolymer doped by nanoparticles

NASA Astrophysics Data System (ADS)

Mu, Dan; Li, Jian-Quan; Feng, Sheng-Yu

2013-03-01

The compatibility of six groups of 12 miktoarm poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA) copolymers is studied at 270, 298 and 400 K via mesoscopic modeling. The values of the order parameters depend on both the architectures of the block copolymers and the simulation temperature, while the tendency to change of the order parameters at low temperature, such as 270 and 298 K, is nearly the same. However, the values of order parameters of the copolymer in the same group are the same at high temperature, i.e. 400 K. Obviously, temperature has a more obvious effect on long and PEO-rich chains. A study of plain copolymers doped with nanoparticles shows that the microscopic phase is influenced by not only the properties of the nanoparticles, such as the size, number and density, but also the composition and architecture of copolymers. Increasing the size and the number of the nanoparticles used as a dopant plays the most significant role on determining the phase morphologies of the copolymers at lower and higher temperature, respectively. In paricular, the 23141 and 23241-type copolymers, which are both of PEO-rich composition, presents microscopic phase separation as perforated lamallae phase morphologies at 400 K, alternated with PEO and PMMA components.

The on-bead digestion of protein corona on nanoparticles by trypsin immobilized on the magnetic nanoparticle.

PubMed

Hu, Zhengyan; Zhao, Liang; Zhang, Hongyan; Zhang, Yi; Wu, Ren'an; Zou, Hanfa

2014-03-21

Proteins interacting with nanoparticles would form the protein coronas on the surface of nanoparticles in biological systems, which would critically impact the biological identities of nanoparticles and/or result in the physiological and pathological consequences. The enzymatic digestion of protein corona was the primary step to achieve the identification of protein components of the protein corona for the bottom-up proteomic approaches. In this study, the investigation on the tryptic digestion of protein corona by the immobilized trypsin on a magnetic nanoparticle was carried out for the first time. As a comparison with the usual overnight long-time digestion and the severe self-digestion of free trypsin, the on-bead digestion of protein corona by the immobilized trypsin could be accomplished within 1h, along with the significantly reduced self-digestion of trypsin and the improved reproducibility on the identification of proteins by the mass spectrometry-based proteomic approach. It showed that the number of identified bovine serum (BS) proteins on the commercial Fe3O4 nanoparticles was increased by 13% for the immobilized trypsin with 1h digestion as compared to that of using free trypsin with even overnight digestion. In addition, the on-bead digestion of using the immobilized trypsin was further applied on the identification of human plasma protein corona on the commercial Fe3O4 nanoparticles, which leads the efficient digestion of the human plasma proteins and the identification of 149 human plasma proteins corresponding to putative critical pathways and biological processes. Copyright © 2014 Elsevier B.V. All rights reserved.

Analytical determination of the reducing and stabilization agents present in different Zostera noltii extracts used for the biosynthesis of gold nanoparticles.

PubMed

Zarzuela, Rafael; Luna, Manuel Jesús; Gil, María Luisa Almoraima; Ortega, María Jesús; Palacios-Santander, José María; Naranjo-Rodríguez, Ignacio; Delgado, Juan José; Cubillana-Aguilera, Laura María

2018-02-01

The objective of this work was to ascertain the nature of the components responsible for the reducing and stabilizing properties of Zostera noltii extracts that lead to gold nanoparticle formation using chemical techniques of analysis. In order to achieve this aim, we try the synthesis of AuNPs with three different extracts from plants collected in the Bay of Cádiz (Spain). The n-butanol extract produced the best results. Taking this into account, four fractions were isolated by Sephadex LH-20 column chromatography from this extract and we studied their activity. The chemical study of these fractions led to the isolation of several flavone sulfates and these were identified as the species' responsible for the formation and stabilization of the AuNPs. Flavone sulfates were purified by high performance liquid chromatography and the structures were established by means of spectroscopic methods nuclear magnetic resonance and mass spectroscopy. AuNPs have an average lifetime of about 16weeks. Additionally, the morphology and crystalline phase of the gold nanoparticles were characterized by transmission electron microscopy. The composition of the nanoparticles was evaluated by electron diffraction and energy dispersive X-ray spectroscopy. An 88% of the gold nanoparticles has a diameter in the range 20-35nm, with an average size of 26±2nm. Copyright © 2017 Elsevier B.V. All rights reserved.

Harmonic decomposition of magneto-optical signal from suspensions of superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Patterson, Cody; Syed, Maarij; Takemura, Yasushi

2018-04-01

Magnetic nanoparticles (MNPs) are widely used in biomedical applications. Characterizing dilute suspensions of superparamagnetic iron oxide nanoparticles (SPIONs) in bio-relevant media is particularly valuable for magnetic particle imaging, hyperthermia, drug delivery, etc. Here, we study dilute aqueous suspensions of single-domain magnetite nanoparticles using an AC Faraday rotation (FR) setup. The setup uses an oscillating magnetic field (800 Hz) which generates a multi-harmonic response. Each harmonic is collected and analyzed using the Fourier components of the theoretical signal determined by a Langevin-like magnetization. With this procedure, we determine the average magnetic moment per particle μ , particle number density n, and Verdet constant of the sample. The fitted values of μ and n are shown to be consistent across each harmonic. Additionally, we present the results of these parameters as n is varied. The large values of μ reveal the possibility of clustering as reported in other literature. This suggests that μ is representative of the average magnetic moment per cluster of nanoparticles. Multiple factors, including the external magnetic field, surfactant degradation, and laser absorption, can contribute to dynamic and long-term aggregation leading to FR signals that represent space- and time-averaged sample parameters. Using this powerful analysis procedure, future studies are aimed at determining the clustering mechanisms in this AC system and characterizing SPION suspensions at different frequencies and viscosities.

Volume Labeling with Alexa-Fluor Dyes and Surface Functionalization of Highly Sensitive Fluorescent SiO2 Nanoparticles

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

Wang, Wei; Foster, Carmen M; Morrell-Falvey, Jennifer L

2013-01-01

A new synthesis approach is described that allows the direct incorporation of fluorescent labels into the volume or body of SiO2 nanoparticles. In this process, fluorescent Alexa Fluor dyes with different emission wavelengths were covalently incorporated into the SiO2 nanoparticles during their formation by the hydrolysis of tetraethoxysilane. The dye molecules were homogeneously distributed throughout the SiO2 nanoparticles. The quantum yields of the Alexa Fluor volume-labeled SiO2 nanoparticles were much higher than nanoparticles labeled using conventional organic dyes. The size of the resulting nanoparticles was controlled using microemulsion reaction media with sizes in the range of 20-100 nm and amore » polydispersity of <15%. In comparison with conventional surface tagged particles created by post-synthesis modification, this process maintains the physical and surface chemical properties that have the most pronounced effect on colloidal stability and interactions with their surroundings. These volume-labeled nanoparticles have proven to be extremely robust, showing excellent signal strength, negligible photobleaching, and minimal loss of functional organic components. The native or free surface of the volume-labeled particles can be altered to achieve a specific surface functionality without altering fluorescence. Their utility was demonstrated for visualizing the association of surface modified fluorescent particles with cultured macrophages. Differences in particle agglomeration and cell association were clearly associated with differences in observed nanoparticle toxicity. The capacity to maintain particle fluorescence while making significant changes to surface chemistry makes these particles extremely versatile and useful for studies of particle agglomeration, uptake, and transport in environmental and biological systems.« less

Polymer Stabilized Nanosuspensions Formed via Flash Nanoprecipitation: Nanoparticle Formation, Formulation, and Stability

NASA Astrophysics Data System (ADS)

Zhu, ZhengXi

Nanoparticles loaded with hydrophobic components (e.g., active pharmaceutical ingredients, medical diagnostic agents, nutritional or personal care chemicals, catalysts, dyes/pigments, and substances with exceptional magnetic/optical/electronic/thermal properties) have tremendous industrial applications. The common desire is to efficiently generate nanoparticles with a desired size, size distribution, and size stability. Recently, Flash NanoPrecipition (FNP) technique with a fast, continuous, and easily scalable process has been developed to efficiently generate hydrophobe-loaded nanoparticles. This dissertation extended this technique, optimized process conditions and material formulations, and gave new insights into the mechanism and kinetics of nanoparticle formation. This dissertation demonstrated successful generation of spherical beta-carotene nanoparticles with an average diameter of 50--100 nm (90 wt% nanoparticles below 200 nm), good size stability (maintained an average diameter below 200 nm for at least one week in saline), and much higher loading (80--90 wt%) than traditional carriers, such as micelles and polymersomes (typically <20 wt%). Moreover, the nanoparticles are amorphous and expected to have a high dissolution rate and bioavailability. To give insights into the mechanism and kinetics of nanoparticle formation, much remarkable evidence supported the kinetically frozen structures of the nanoparticles rather than the thermodynamic equilibrium micelles. Time scales of the particle formation via FNP were proposed. To optimize the material formulations, either polyelectrolytes (i.e., epsilon-polylysine, branched and linear poly(ethylene imine), and chitosan) or amphiphilic diblock copolymers (i.e., polystyrene-b-poly(ethylene glycol) (PS-b-PEG), polycarprolactone-b-poly(ethylene glycol) (PCL-b-PEG), poly(lactic acid)-b-poly(ethylene glycol) (PLA-b-PEG), and poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-b-PEG)) were selectively screened to study the nanoparticle size, distribution, and stability. The effect of the molecular weight of the polymers and pH were also studied. Chitosan and PLGA-b-PEG best stabilized the beta-carotene nanoparticles. Solubility of the hydrophobic drug solute in the aqueous mixture was considered to dominate the nanoparticle stability (i.e., size and morphology) in terms of Ostwald ripening and recrystallization. The lower solubility the drug is of, the greater stability the nanoparticles have. Chemically bonding drug compounds with cleavable hydrophobic moieties to form prodrugs were used to enhance their hydrophobicity and thus the nanoparticle stability. It opened a generic strategy to enhance the stability of nanoparticles formed via FNP. beta-carotene, paclitaxel, paclitaxel prodrug, betulin, hydrocortisone, and hydrocortisone prodrug as the drugs were studied. Solubility parameter (delta), and octanol/water partition coefficients (LogP), provide hydrophobicity indicators for the compounds. LogP showed a good correlation with the nanoparticle stability. An empirical rule was built to conveniently predict particle stability for randomly selected drugs. To optimize the process conditions, two-stream confined impinging jet mixer (CIJ) and four-stream confined vortex jet mixer were used. The particle size was studied by varying drug and polymer concentrations, and flow rate (corresponding to Reynolds number (Re)). To extend the FNP technique, this dissertation demonstrated successful creation of stabilized nanoparticles by integrating an in-situ reactive coupling of a hydrophilic polymer block with a hydrophobic one with FNP. The kinetics of the fast coupling reaction was studied. This dissertation also introduced polyelectrolytes (i.e., epsilon-polylysine, poly(ethylene imine), and chitosan) into FNP to electrosterically stabilize nanoparticles.

1-D Metal Nanobead Arrays within Encapsulated Nanowires via a Red-Ox-Induced Dewetting: Mechanism Study by Atom-Probe Tomography.

PubMed

Sun, Zhiyuan; Tzaguy, Avra; Hazut, Ori; Lauhon, Lincoln J; Yerushalmi, Roie; Seidman, David N

2017-12-13

Metal nanoparticle arrays are excellent candidates for a variety of applications due to the versatility of their morphology and structure at the nanoscale. Bottom-up self-assembly of metal nanoparticles provides an important complementary alternative to the traditional top-down lithography method and makes it possible to assemble structures with higher-order complexity, for example, nanospheres, nanocubes, and core-shell nanostructures. Here we present a mechanism study of the self-assembly process of 1-D noble metal nanoparticles arrays, composed of Au, Ag, and AuAg alloy nanoparticles. These are prepared within an encapsulated germanium nanowire, obtained by the oxidation of a metal-germanium nanowire hybrid structure. The resulting structure is a 1-D array of equidistant metal nanoparticles with the same diameter, the so-called nanobead (NB) array structure. Atom-probe tomography and transmission electron microscopy were utilized to investigate the details of the morphological and chemical evolution during the oxidation of the encapsulated metal-germanium nanowire hybrid-structures. The self-assembly of nanoparticles relies on the formation of a metal-germanium liquid alloy and the migration of the liquid alloy into the nanowire, followed by dewetting of the liquid during shape-confined oxidation where the liquid column breaks-up into nanoparticles due to the Plateau-Rayleigh instability. Our results demonstrate that the encapsulating oxide layer serves as a structural scaffold, retaining the overall shape during the eutectic liquid formation and demonstrates the relationship between the oxide mechanical properties and the final structural characteristics of the 1-D arrays. The mechanistic details revealed here provide a versatile tool-box for the bottom-up fabrication of 1-D arrays nanopatterning that can be modified for multiple applications according to the RedOx properties of the material system components.

The mechanisms for nanoparticle surface diffusion and chain self-assembly determined from real-time nanoscale kinetics in liquid

DOE PAGES

Woehl, Taylor J.; Prozorov, Tanya

2015-08-20

The mechanisms for nanoparticle self-assembly are often inferred from the morphology of the final nanostructures in terms of attractive and repulsive interparticle interactions. Understanding how nanoparticle building blocks are pieced together during self-assembly is a key missing component needed to unlock new strategies and mechanistic understanding of this process. Here we use real-time nanoscale kinetics derived from liquid cell transmission electron microscopy investigation of nanoparticle self-assembly to show that nanoparticle mobility dictates the pathway for self-assembly and final nanostructure morphology. We describe a new method for modulating nanoparticle diffusion in a liquid cell, which we employ to systematically investigate themore » effect of mobility on self-assembly of nanoparticles. We interpret the observed diffusion in terms of electrostatically induced surface diffusion resulting from nanoparticle hopping on the liquid cell window surface. Slow-moving nanoparticles self-assemble predominantly into linear 1D chains by sequential attachment of nanoparticles to existing chains, while highly mobile nanoparticles self-assemble into chains and branched structures by chain–chain attachments. Self-assembly kinetics are consistent with a diffusion-driven mechanism; we attribute the change in self-assembly pathway to the increased self-assembly rate of highly mobile nanoparticles. Furthermore, these results indicate that nanoparticle mobility can dictate the self-assembly mechanism and final nanostructure morphology in a manner similar to interparticle interactions.« less

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

Rouleau, Christopher M.; Puretzky, Alexander A.; Geohegan, David B.

The slowing of Pt nanoparticles in argon background gas was characterized by Rayleigh scattering imaging using a plume of nanoparticles generated by femtosecond laser through thin film ablation (fs-TTFA) of 20 nanometers-thick Pt films. The ablation was performed at threshold laser energy fluences for complete film removal to provide a well-defined plume consisting almost entirely of nanoparticles traveling with a narrow velocity distribution, providing a unique system to unambiguously characterize the slowing of nanoparticles during interaction with background gases. Nanoparticles of ~200 nm diameter were found to decelerate in background Ar gas with pressures less than 50 Torr in goodmore » agreement with a linear drag model in the Epstein regime. Based on this model, the stopping distance of small nanoparticles in the plume was predicted and tested by particle collection in an off-axis geometry, and size distribution analysis by transmission electron microscopy. These results permit a basis to interpret nanoparticle propagation through background gases in laser ablation plumes that contain mixed components.« less

Optical transverse spin coupling through a plasmonic nanoparticle for particle-identification and field-mapping.

PubMed

Yang, A P; Du, L P; Meng, F F; Yuan, X C

2018-05-17

Electromagnetic fields at near-field exhibit distinctive properties with respect to their free-space counterparts. In particular, an optical transverse spin appearing in a confined electromagnetic field provides the foundation for many intriguing physical effects and applications. We present a transverse spin coupling configuration where plasmonic nanoparticles are employed to couple the transverse spin in a focused beam to that of a surface plasmon polariton. The plasmonic resonance of nanoparticles on a metal film plays a significant role in transverse spin coupling. We demonstrate in experiments that Ag and Au nanoparticles yield distinct imaging patterns when scanned over a focused field, because of their different plasmonic responses to the transverse and longitudinal electric fields. Such resonance-dependent spin-coupling enables the identification of nanoparticles using a focused field, as well as electric field mapping of a specific field component of a focused beam using a plasmonic nanoparticle. These interesting findings regarding the transverse spin coupling with a plasmonic nanoparticle may find valuable applications in near-field and nano-optics.

Multi-component Fe–Ni hydroxide nanocatalyst for oxygen evolution and methanol oxidation reactions under alkaline conditions

DOE PAGES

Candelaria, Stephanie L.; Bedford, Nicholas M.; Woehl, Taylor J.; ...

2016-11-29

Here, iron-incorporated nickel-based materials show promise as catalysts for the oxygen evolution reac-tion (OER) half-reaction of water electrolysis. Nickel has also exhibited high catalytic activity for methanol oxidation, particularly when in the form of a bimetallic catalyst. In this work, bimetallic iron-nickel nanoparticles were synthesized using a multi-step procedure in water under ambient conditions. When compared to monometallic iron and nickel nanoparticles, Fe-Ni nanoparticles show enhanced catalytic activity for both OER and methanol oxidation under alkaline conditions. At 1 mA/cm 2, the overpotential for monometallic iron and nickel nanoparticles was 421 mV and 476 mV, respectively, while the bimetallic Fe-Nimore » nanoparticles had a greatly reduced overpotential of 256 mV. At 10 mA/cm 2, bimetallic Fe-Ni nanoparticles had an overpotential of 311 mV. Spec-troscopy characterization suggests that the primary phase of nickel in Fe-Ni nanoparticles is the more disordered alpha phase of nickel hydroxide.« less

BX CY NZ nanotubes and nanoparticles

DOEpatents

Cohen, Marvin Lou; Zettl, Alexander Karlwalter

2001-01-01

The invention provides crystalline nanoscale particles and tubes made from a variety of stoichiometries of B.sub.x C.sub.y N.sub.z where x, y, and z indicate a relative amount of each element compared to the others and where no more than one of x, y, or z are zero for a single stoichiometry. The nanotubes and nanoparticles are useful as miniature electronic components, such as wires, coils, schotky barriers, diodes, etc. The nanotubes and nanoparticles are also useful as coating that will protect an item from detection by electromagnetic monitoring techniques like radar. The nanotubes and nanoparticles are additionally useful for their mechanical properties, being comparable in strength and stiffness to the best graphite fibers or carbon nanotubes. The inventive nanoparticles are useful in lubricants and composites.

PHOTONICS AND NANOTECHNOLOGY Laser synthesis and modification of composite nanoparticles in liquids

NASA Astrophysics Data System (ADS)

Tarasenko, N. V.; Butsen, A. V.

2010-12-01

The works devoted to the formation and modification of nanoparticles using laser ablation of solid targets in liquids are reviewed. Several approaches to implement laser ablation in liquids, aimed at synthesising nanoparticles of complex composition, are considered: direct laser ablation of a target of corresponding composition, laser ablation of a combined target composed of two different metals, laser irradiation of a mixture of two or more colloidal solutions, and laser ablation in reactive liquids. The properties of two-component bimetallic systems (Ag — Cu, Ag — Au), semiconductor nanocrystals (ZnO, CdSe), chalcopyrite nanoparticles, and doped oxide nanoparticles (ZnO:Ag, Gd2O2:Tb3+) formed as a result of single- and double-pulse laser ablation in different liquids (water, ethanol, acetone, solutions of polysaccharides) are discussed.

Structural and optical characterization of Eu3+ doped beta-Ga2O3 nanoparticles using a liquid-phase precursor method.

PubMed

Kim, Moung-O; Kang, Bongkyun; Yoon, Daeho

2013-08-01

Eu3+ doped beta-Ga2O3 and non-doped beta-Ga2O3 nanoparticles were synthesized at 800 degrees C using a liquid-phase precursor (LPP) method, with different annealing times and Eu3+ ion concentrations. Eu3+ doped beta-Ga2O3 nanoparticles showed broad XRD peaks, revealing a second phase compared with the non-doped beta-Ga2O3 nanoparticles. The cathode luminescence (CL) spectra of beta-Ga2O3 and Eu3+ doped beta-Ga2O3 nanoparticles showed a broad band emission (300-500 nm) of imperfection and two component emissions. The luminescence quenching properties of Eu3+ dopant ion concentration appeared gradually beyond 5 mol% in our investigation.

Tunable porous nanoallotropes prepared by post-assembly etching of binary nanoparticle superlattices

NASA Astrophysics Data System (ADS)

Udayabhaskararao, Thumu; Altantzis, Thomas; Houben, Lothar; Coronado-Puchau, Marc; Langer, Judith; Popovitz-Biro, Ronit; Liz-Marzán, Luis M.; Vuković, Lela; Král, Petr; Bals, Sara; Klajn, Rafal

2017-10-01

Self-assembly of inorganic nanoparticles has been used to prepare hundreds of different colloidal crystals, but almost invariably with the restriction that the particles must be densely packed. Here, we show that non-close-packed nanoparticle arrays can be fabricated through the selective removal of one of two components comprising binary nanoparticle superlattices. First, a variety of binary nanoparticle superlattices were prepared at the liquid-air interface, including several arrangements that were previously unknown. Molecular dynamics simulations revealed the particular role of the liquid in templating the formation of superlattices not achievable through self-assembly in bulk solution. Second, upon stabilization, all of these binary superlattices could be transformed into distinct “nanoallotropes”—nanoporous materials having the same chemical composition but differing in their nanoscale architectures.

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.

Highly Tunable Heterojunctions from Multimetallic Sulfide Nanoparticles and Silver Nanowires.

PubMed

Liu, Dongliang; Liu, Yong; Huang, Peng; Zhu, Cheng; Kang, Zhenhui; Shu, Jie; Chen, Muzi; Zhu, Xing; Guo, Jun; Zhuge, Lanjian; Bu, Xianhui; Feng, Pingyun; Wu, Tao

2018-05-04

A facile and general strategy is presented to create well-defined heterojunctions with ultra-small multimetallic sulfide nanoparticles (MMSNPs) uniformly coated on sliver nanowires. A unique aspect of this method is the atomic-level pre-integration of multimetallic components by exploiting recently developed supertetrahedral metal sulfide nanoclusters. The use of such nanoclusters also enables the convenient formation of the ultrathin interfacial Ag 2 S layer via etching. The heterojunctions (denoted as MMSNPs/Ag 2 S/Ag-NWs) benefit from adjustable multimetallic components and display tunable visible-light-driven photocatalytic performance owing to the synergistic effect of multimetallic components from MMSNPs and the high carrier mobility of Ag-NWs. The synthetic strategy opens new routes to designing and fabricating various heterojunctions with multimetallic components, which could further expand their applications in catalysis, electronics, and photonics. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronic properties of hybrid Cu2S/Ru semiconductor/metallic-cage nanoparticles.

PubMed

Bekenstein, Yehonadav; Vinokurov, Kathy; Banin, Uri; Millo, Oded

2012-12-21

Hybrid inorganic nanoparticles, comprising a semiconducting Cu(2)S quantum-dot (QD) core encapsulated by a metallic Ru cage-like shell, and each of their individual components, are studied via scanning tunneling spectroscopy. Bare Cu(2)S QDs show nearly identical semiconducting-like I-V characteristics while the empty Ru cages exhibit single electron tunneling effects-the Coulomb blockade and staircase. Surprisingly, in some cases negative differential conductance features, with periodicity that correlates to the Coulomb staircase, were observed. The tunneling spectra measured on the hybrid QDs varies greatly along a single particle, manifesting synergetic electrical properties that originate from this unique semiconducting-metallic interface.

Redox Sorption of Oxygen Dissolved in Water on Copper Nanoparticles in an Ion Exchange Matrix

NASA Astrophysics Data System (ADS)

Vakhnin, D. D.; Pridorogina, V. E.; Polyanskii, L. N.; Kravchenko, T. A.; Gorshkov, V. S.

2018-01-01

The redox sorption of molecular oxygen from water by a thin granular layer of a copper-ion exchanger nanocomposite in the currentless mode and under cathodic polarization is studied. The speed of propagation of the boundaries of the chemical reaction of stepwise oxidation of copper nanoparticles under the conditions of polarization slows considerably. At the same time, the amount of electrochemically regenerated copper from the resulting oxides that is capable of interacting with oxygen again grows. The stationarity of the redox sorption of oxygen is due to the equality of the rates of oxidation and reduction of the metallic component of the composite.

Preparation of novel stable antibacterial nanoparticles using hydroxyethylcellulose and application in paper.

PubMed

Wei, Dafu; Chen, Yan; Zhang, Youwei

2016-01-20

Taking advantage of the self-assembly between the components, novel stable antibacterial nanoparticles were efficiently fabricated via a facile one-step co-polymerization of acrylic acid (AA) and N,N'-methylenebisacrylamide (MBA) on a mixed aqueous solution of poly(hexamethylene guanidine hydrochloride) (PHMG) and hydroxyethylcellulose (HEC). The z-average hydrodynamic diameters of the nanoparticles ranged from 220 nm to 450 nm. The inner layer of the nanoparticles is composed of water-insoluble interpolymer complexes of PHMG and PAA networks, while the outer layer is composed of PHMG and HEC. The nanoparticles are stabilized by electrostatic interactions, hydrogen bonding interactions, and the chemical bonds. The nanoparticle solution remained stable in a wide pH range of 2.0-12.0 and at salt concentrations below 0.25 mol/L. The nanoparticles were incorporated into handsheets using a dipping treatment. The resulted handsheets exhibited excellent antimicrobial activities even after multiple water washing treatments. The nanoparticles are promising in fabricating paper, water-based coatings and textiles with permanent antibacterial activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wettability of Complex Fluids and Surfactant Capped Nanoparticle-Induced Quasi-Universal Wetting Behavior.

PubMed

Harikrishnan, A R; Dhar, Purbarun; Agnihotri, Prabhat K; Gedupudi, Sateesh; Das, Sarit Kumar

2017-06-22

Even though there are quite large studies on wettability of aqueous surfactants and a few studies on effects of nanoparticles on wettability of colloids, to the best of authors' knowledge, there is no study reported on the combined effect of surfactant and nanoparticles in altering the wettability. The present study, for the first time, reports an extensive experimental and theoretical study on the combined effect of surfactants and nanoparticles on the wettability of complex fluids such as nanocolloids on different substrates, ranging from hydrophilic with a predominantly polar surface energy component (silicon wafer and glass) to near hydrophobic range with a predominantly dispersive component of surface energy (aluminum and copper substrates). Systematically planned experiments are carried out to segregate the contributing effects of surfactants, particles, and combined particle and surfactants in modulating the wettability. The mechanisms and the governing parameters behind the interactions of nanocolloids alone and of surfactant capped nanocolloids with different surfaces are found to be grossly different. The article, for the first time, also analyzes the interplay of the nature of surfaces, surfactant and particle concentrations on contact angle, and contact angle hysteresis (CAH) of particle and surfactant impregnated colloidal suspensions. In the case of nanoparticle suspensions, the contact angle is observed to decrease for the hydrophobic system and increase for the hydrophilic systems considered. On the contrary, the combined particle and surfactant colloidal system shows a quasi-unique wetting behavior of decreasing contact angle with particle concentration on all substrates. Also interestingly, the combined particle surfactant system at all particle concentrations shows a wetting angle much lower than that of the only-surfactant case at the same surfactant concentration. Such counterintuitive observations have been explained based on the near-surface interactivity of the particle, fluid, and surfactant molecules based on effective slip length considerations. The CAH analyses of colloidal suspensions at varying surfactant and particle concentrations reveal in-depth physical insight into contact line pinning, and a unique novel relationship is established between the contact angle and differential energy for distorting the instantaneous contact angle for a pinned sessile droplet. A detailed theoretical analysis of the governing parameters influencing the wettability has been presented invoking the principles of DLVO (Derjaguin-Landau-Verwey-Overbeek), surface energy and interaction parameters influencing at the molecular scale, and the theoretical framework is found to support the experimental observations.

A method for optical imaging and monitoring of the excretion of fluorescent nanocomposites from the body using artificial neural networks.

PubMed

Sarmanova, Olga E; Burikov, Sergey A; Dolenko, Sergey A; Isaev, Igor V; Laptinskiy, Kirill A; Prabhakar, Neeraj; Karaman, Didem Şen; Rosenholm, Jessica M; Shenderova, Olga A; Dolenko, Tatiana A

2018-04-12

In this study, a new approach to the implementation of optical imaging of fluorescent nanoparticles in a biological medium using artificial neural networks is proposed. The studies were carried out using new synthesized nanocomposites - nanometer graphene oxides, covered by the poly(ethylene imine)-poly(ethylene glycol) copolymer and by the folic acid. We present an example of a successful solution of the problem of monitoring the removal of nanocomposites based on nGO and their components with urine using fluorescent spectroscopy and artificial neural networks. However, the proposed method is applicable for optical imaging of any fluorescent nanoparticles used as theranostic agents in biological tissue. Copyright © 2018. Published by Elsevier Inc.

A palladium label to monitor nanoparticle-assisted drug delivery of a photosensitizer into tumor spheroids by elemental bioimaging.

PubMed

Niehoff, Ann-Christin; Moosmann, Aline; Söbbing, Judith; Wiehe, Arno; Mulac, Dennis; Wehe, Christoph A; Reifschneider, Olga; Blaske, Franziska; Wagner, Sylvia; Sperling, Michael; von Briesen, Hagen; Langer, Klaus; Karst, Uwe

2014-01-01

In this study, the cellular uptake of the second generation photosensitizer 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (mTHPP) was investigated using laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) at a spatial resolution of 10 μm. To achieve high sensitivity, the photosensitizer was tagged with palladium. As a tumor model system, a 3D cell culture of the TKF-1 cell line was used. These tumor spheroids were incubated with the Pd-tagged photosensitizer embedded in poly(lactic-co-glycolic acid) (PLGA) nanoparticles to investigate the efficiency of nanoparticle based drug delivery. An accumulation of the drug in the first cell layers of the tumor spheroid was observed. In the case of nanoparticle based drug delivery, a significantly more homogeneous distribution of the photosensitizer was achieved, compared to tumor spheroids incubated with the dissolved photosensitizer without the nanoparticular drug delivery system. The infiltration depth of the Pd-tagged photosensitizer could not be increased with rising incubation time, which can be attributed to the adsorption of the photosensitizer onto cellular components.

Multi-functionality Redefined with Colloidal Carotene Carbon Nanoparticles for Synchronized Chemical Imaging, Enriched Cellular Uptake and Therapy.

PubMed

Misra, Santosh K; Mukherjee, Prabuddha; Chang, Huei-Huei; Tiwari, Saumya; Gryka, Mark; Bhargava, Rohit; Pan, Dipanjan

2016-07-11

Typically, multiplexing high nanoparticle uptake, imaging, and therapy requires careful integration of three different functions of a multiscale molecular-particle assembly. Here, we present a simpler approach to multiplexing by utilizing one component of the system for multiple functions. Specifically, we successfully synthesized and characterized colloidal carotene carbon nanoparticle (C(3)-NP), in which a single functional molecule served a threefold purpose. First, the presence of carotene moieties promoted the passage of the particle through the cell membrane and into the cells. Second, the ligand acted as a potent detrimental moiety for cancer cells and, finally, the ligands produced optical contrast for robust microscopic detection in complex cellular environments. In comparative tests, C(3)-NP were found to provide effective intracellular delivery that enables both robust detection at cellular and tissue level and presents significant therapeutic potential without altering the mechanism of intracellular action of β-carotene. Surface coating of C(3) with phospholipid was used to generate C(3)-Lipocoat nanoparticles with further improved function and biocompatibility, paving the path to eventual in vivo studies.

Multi-functionality Redefined with Colloidal Carotene Carbon Nanoparticles for Synchronized Chemical Imaging, Enriched Cellular Uptake and Therapy

PubMed Central

Misra, Santosh K.; Mukherjee, Prabuddha; Chang, Huei-Huei; Tiwari, Saumya; Gryka, Mark; Bhargava, Rohit; Pan, Dipanjan

2016-01-01

Typically, multiplexing high nanoparticle uptake, imaging, and therapy requires careful integration of three different functions of a multiscale molecular-particle assembly. Here, we present a simpler approach to multiplexing by utilizing one component of the system for multiple functions. Specifically, we successfully synthesized and characterized colloidal carotene carbon nanoparticle (C3-NP), in which a single functional molecule served a threefold purpose. First, the presence of carotene moieties promoted the passage of the particle through the cell membrane and into the cells. Second, the ligand acted as a potent detrimental moiety for cancer cells and, finally, the ligands produced optical contrast for robust microscopic detection in complex cellular environments. In comparative tests, C3-NP were found to provide effective intracellular delivery that enables both robust detection at cellular and tissue level and presents significant therapeutic potential without altering the mechanism of intracellular action of β-carotene. Surface coating of C3 with phospholipid was used to generate C3-Lipocoat nanoparticles with further improved function and biocompatibility, paving the path to eventual in vivo studies. PMID:27405011

Multi-functionality Redefined with Colloidal Carotene Carbon Nanoparticles for Synchronized Chemical Imaging, Enriched Cellular Uptake and Therapy

NASA Astrophysics Data System (ADS)

Misra, Santosh K.; Mukherjee, Prabuddha; Chang, Huei-Huei; Tiwari, Saumya; Gryka, Mark; Bhargava, Rohit; Pan, Dipanjan

2016-07-01

Typically, multiplexing high nanoparticle uptake, imaging, and therapy requires careful integration of three different functions of a multiscale molecular-particle assembly. Here, we present a simpler approach to multiplexing by utilizing one component of the system for multiple functions. Specifically, we successfully synthesized and characterized colloidal carotene carbon nanoparticle (C3-NP), in which a single functional molecule served a threefold purpose. First, the presence of carotene moieties promoted the passage of the particle through the cell membrane and into the cells. Second, the ligand acted as a potent detrimental moiety for cancer cells and, finally, the ligands produced optical contrast for robust microscopic detection in complex cellular environments. In comparative tests, C3-NP were found to provide effective intracellular delivery that enables both robust detection at cellular and tissue level and presents significant therapeutic potential without altering the mechanism of intracellular action of β-carotene. Surface coating of C3 with phospholipid was used to generate C3-Lipocoat nanoparticles with further improved function and biocompatibility, paving the path to eventual in vivo studies.

Self-assembly approach toward magnetic silica-type nanoparticles of different shapes from reverse block copolymer mesophases.

PubMed

Garcia, Carlos B W; Zhang, Yuanming; Mahajan, Surbhi; DiSalvo, Francis; Wiesner, Ulrich

2003-11-05

In the present study poly(isoprene-block-ethylene oxide), PI-b-PEO, block copolymers are used to structure iron oxide and silica precursors into reverse mesophases, which upon dissolution of the organic matrix lead to well-defined nanoparticles of spheres, cylinders, and plates based on the original structure of the mesophase prepared. The hybrid mesophases with sphere, cylinder, and lamellar morphologies containing the inorganic components in the minority phases are characterized through a combination of small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and electron energy loss spectroscopy (EELS). After heat treatments the respective nanoparticles on mica surfaces are characterized by scanning force microscopy (SFM). X-ray diffraction (XRD) and superconducting quantum interference device (SQUID) magnetometer measurements are performed to demonstrate that the heat treatment leads to the formation of a magnetic gamma-Fe2O3 crystalline phase within the amorphous aluminosilicate. The results pave the way to functional, i.e., magnetic nanoparticles where the size, shape, and iron oxide concentration can be controlled opening a range of possible applications.

Temperature measurements of inverse micelles coated in gold nanoparticles using fluorescence

NASA Astrophysics Data System (ADS)

Daley, Chad; Forrest, James A.; Speller, Ryan; William, Toews; McVeigh, Patrick; Emrick, Todd

2009-03-01

When nanoparticles are subject to laser radiation they have the ability to efficiently absorb energy from the beam and transform this energy into heat. Photothermal therapy uses this phenomenon to irreparably damage tissue surrounding nanoparticle conjugates. Despite the promise of this technique, there is no concensus on the damage mechanism or even the local heating. Here we present an experiment designed to measure local temperatures achieved in such processes. Ligand covered Gold nanoparticles are used to stabalize inverse micelles containing fluorescence dye in the water component. The fluorescence intensity being temperature dependent provides us with a means of measuring the temperature of the micelles as a function of time immediately following a laser pulse.

Stable RNA nanoparticles as potential new generation drugs for cancer therapy☆

PubMed Central

Shu, Yi; Pi, Fengmei; Sharma, Ashwani; Rajabi, Mehdi; Haque, Farzin; Shu, Dan; Leggas, Markos; Evers, B. Mark; Guo, Peixuan

2014-01-01

Human genome sequencing revealed that only ~1.5% of the DNA sequence coded for proteins. More and more evidence has uncovered that a substantial part of the 98.5% so-called “junk” DNAs actually code for noncoding RNAs. Two milestones, chemical drugs and protein drugs, have already appeared in the history of drug development, and it is expected that the third milestone in drug development will be RNA drugs or drugs that target RNA. This review focuses on the development of RNA therapeutics for potential cancer treatment by applying RNA nanotechnology. A therapeutic RNA nanoparticle is unique in that its scaffold, ligand, and therapeutic component can all be composed of RNA. The special physicochemical properties lend to the delivery of siRNA, miRNA, ribozymes, or riboswitches; imaging using fluogenenic RNA; and targeting using RNA aptamers. With recent advances in solving the chemical, enzymatic, and thermodynamic stability issues, RNA nanoparticles have been found to be advantageous for in vivo applications due to their uniform nano-scale size, precise stoichiometry, polyvalent nature, low immunogenicity, low toxicity, and target specificity. In vivo animal studies have revealed that RNA nanoparticles can specifically target tumors with favorable pharmacokinetic and pharmacodynamic parameters without unwanted accumulation in normal organs. This review summarizes the key studies that have led to the detailed understanding of RNA nanoparticle formation as well as chemical and thermodynamic stability issue. The methods for RNA nanoparticle construction, and the current challenges in the clinical application of RNA nanotechnology, such as endosome trapping and production costs, are also discussed. PMID:24270010

Recent progress on nanoparticle-based drug delivery systems for cancer therapy

PubMed Central

Xin, Yanru; Yin, Mingming; Zhao, Liyuan; Meng, Fanling; Luo, Liang

2017-01-01

The development of cancer nanotherapeutics has attracted great interest in the recent decade. Cancer nanotherapeutics have overcome several limitations of conventional therapies, such as nonspecific biodistribution, poor water solubility, and limited bioavailability. Nanoparticles with tuned size and surface characteristics are the key components of nanotherapeutics, and are designed to passively or actively deliver anti-cancer drugs to tumor cells. We provide an overview of nanoparticle-based drug delivery methods and cancer therapies based on tumor-targeting delivery strategies that have been developed in recent years. PMID:28884040

Manganese oxide nanoparticles, methods and applications

DOEpatents

Abruna, Hector D.; Gao, Jie; Lowe, Michael A.

2017-08-29

Manganese oxide nanoparticles having a chemical composition that includes Mn.sub.3O.sub.4, a sponge like morphology and a particle size from about 65 to about 95 nanometers may be formed by calcining a manganese hydroxide material at a temperature from about 200 to about 400 degrees centigrade for a time period from about 1 to about 20 hours in an oxygen containing environment. The particular manganese oxide nanoparticles with the foregoing physical features may be used within a battery component, and in particular an anode within a lithium battery to provide enhanced performance.

Methods for the In Vitro Characterization of Nanomedicines—Biological Component Interaction

PubMed Central

Fornaguera, Cristina; Solans, Conxita

2017-01-01

The design of colloidal nanosystems intended for biomedical applications, specifically in the field of personalized medicine, has increased notably in the last years. Consequently, a variety of characterization techniques devoted to studying nanomedicine interactions with proteins and cells have been developed, since a deep characterization of nanosystems is required before starting preclinical and clinical studies. In this context, this review aims to summarize the main techniques used to assess the interaction of nanomedicines with biological systems, highlighting their advantages and disadvantages. Testing designed nanomaterials with these techniques is required in order to have more information about their behavior on a physiological environment. Moreover, techniques used to study the interaction of nanomedicines with proteins, such as albumin and fibrinogen, are summarized. These interactions are not desired, since they usually are the first signal to the body for the activation of the immune system, which leads to the clearance of the exogenous components. On the other hand, techniques for studying the cell toxicity of nanosystems are also summarized, since this information is required before starting preclinical steps. The translation of knowledge from novel designed nanosystems at a research laboratory scale to real human therapies is usually a limiting or even a final point due to the lack of systematic studies regarding these two aspects: nanoparticle interaction with biological components and nanoparticle cytotoxicity. In conclusion, this review will be a useful support for those scientists aiming to develop nanosystems for nanomedicine purposes. PMID:28134833

Multifunctional nanoparticles for drug/gene delivery in nanomedicine

NASA Astrophysics Data System (ADS)

Seale, Mary-Margaret; Zemlyanov, Dimitry; Cooper, Christy L.; Haglund, Emily; Prow, Tarl W.; Reece, Lisa M.; Leary, James F.

2007-02-01

Multifunctional nanoparticles hold great promise for drug/gene delivery. Multilayered nanoparticles can act as nanomedical systems with on-board "molecular programming" to accomplish complex multi-step tasks. For example, the targeting process has only begun when the nanosystem has found the correct diseased cell of interest. Then it must pass the cell membrane and avoid enzymatic destruction within the endosomes of the cell. Since the nanosystem is only about one millionth the volume of a human cell, for it to have therapeutic efficacy with its contained package, it must deliver that drug or gene to the appropriate site within the living cell. The successive de-layering of these nanosystems in a controlled fashion allows the system to accomplish operations that would be difficult or impossible to do with even complex single molecules. In addition, portions of the nanosystem may be protected from premature degradation or mistargeting to non-diseased cells. All of these problems remain major obstacles to successful drug delivery with a minimum of deleterious side effects to the patient. This paper describes some of the many components involved in the design of a general platform technology for nanomedical systems. The feasibility of most of these components has been demonstrated by our group and others. But the integration of these interacting sub-components remains a challenge. We highlight four components of this process as examples. Each subcomponent has its own sublevels of complexity. But good nanomedical systems have to be designed/engineered as a full nanomedical system, recognizing the need for the other components.

Fe-containing nanoparticles used as effective catalysts of lignin reforming to syngas and hydrogen assisted by microwave irradiation

NASA Astrophysics Data System (ADS)

Tsodikov, M. V.; Ellert, O. G.; Nikolaev, S. A.; Arapova, O. V.; Bukhtenko, O. V.; Maksimov, Yu. V.; Kirdyankin, D. I.; Vasil'kov, A. Yu.

2018-03-01

Active iron-containing nanosized components have been formed on the lignin surface. The metal was deposited on the lignin from an ethanol solution of Fe(acac)3 and from a colloid solution of iron metal particles obtained beforehand by metal vapor synthesis. These active components are able to absorb microwave radiation and are suitable for microwave-assisted high-rate dehydrogenation and dry reforming of lignin without addition of a carbon adsorbent, as a supplementary radiation absorbing material, to the feedstock. The dependence of the solid lignin heating dynamics on the concentration of supported iron particles was investigated. The threshold Fe concentration equal to 0.5 wt.%, providing the highest rate of sample heating up to the reforming and plasma generation temperature was identified. The microstructure and magnetic properties of iron-containing nanoparticles supported on lignin were studied before and after the reforming. The Fe3O4 nanoparticles and also core-shell Fe3O4@γ-Fe-C nanostructures are formed during the reforming of lignin samples. The catalytic performance of iron-based nanoparticles toward the lignin conversion is manifested as increasing selectivity to hydrogen and syngas, which reaches 94% at the Fe concentration of 2 wt.%. It was found that with microwave irradiation under argon, hydrogen predominates in the gas. In the CO2 atmosphere, dry reforming takes place to give syngas with the CO/H2 ratio of 0.9. In both cases, the degree of hydrogen recovery from lignin reaches 90-94%. [Figure not available: see fulltext.

Modifying Si-based consolidants through the addition of colloidal nano-particles

NASA Astrophysics Data System (ADS)

Ksinopoulou, E.; Bakolas, A.; Moropoulou, A.

2016-04-01

The modification of silicon-based stone consolidants has been the subject of many scientific studies aiming to overcome the commonly reported drawbacks of these materials, such as the tendency to shrink and crack during drying. The addition of nano-particle dispersions into silica matrix has been found to enhance their effectiveness in several ways. Objective of the current research was to study the preparation of particle-modified consolidants (PMC), consisting of an ethyl silicate matrix (TEOS) loaded with colloidal silica (SiO2) nano-particles and oxide titania (TiO2) particles. The effect of the polyacrylic acid on the dispersion stability was also investigated, by varying its concentration into PMC samples. The prepared materials were allowed to dry in two different relative humidity environments and then evaluated based on their stability in the sol phase, the aggregation sizes, determined through dynamic light scattering, the % solids content and their morphological characteristics, observed via scanning electron microscopy (SEM-EDAX). Mercury intrusion porosimetry was also applied to investigate the microstructural characteristics and differences between the prepared consolidants. Significant role in the final form of the material is played by both the initial molar ratios in the mixtures, as well as the conditions where the drying and aging takes place. Based on the results, the three-component PMCs appear to be promising in stone consolidation, as they show a reduction in cracking and shrinkage during drying and a more porous network, compared with the siliceous material, or the two-component TEOS-SiO2 formulation.

Free Volume Structure of Acrylic-Type Dental Nanocomposites Tested with Annihilating Positrons.

PubMed

Shpotyuk, Olha; Ingram, Adam; Shpotyuk, Oleh

2016-12-01

Positron annihilation spectroscopy in lifetime measuring mode exploring conventional fast-fast coincidence ORTEC system is employed to characterize free volume structure of commercially available acrylic-type dental restorative composite Charisma® (Heraeus Kulzer GmbH, Germany). The measured lifetime spectra for uncured and light-cured composites are reconstructed from unconstrained x3-term fitting and semi-empirical model exploring x3-x2-coupling decomposition algorithm. The governing channel of positron annihilation in the composites studied is ascribed to mixed positron-Ps trapping, where Ps decaying in the third component is caused entirely by input from free-volume holes in polymer matrix, while the second component is defined by free positron trapping in interfacial free-volume holes between filler nanoparticles and surrounded polymer matrix. Microstructure scenario of the photopolymerization shrinkage includes cross-linking of structural chains in polymer matrix followed by conversion of bound positron-electron (positronium) traps in positron-trapping interfacial free-volume voids in a vicinity of agglomerated filler nanoparticles.

Tuning optical properties of water-soluble CdTe quantum dots for biological applications

NASA Astrophysics Data System (ADS)

Schulze, Anne S.; Tavernaro, Isabella; Machka, Friederike; Dakischew, Olga; Lips, Katrin S.; Wickleder, Mathias S.

2017-02-01

In this study, two different synthetic methods in aqueous solution are presented to tune the optical properties of CdTe and CdSe semiconductor nanoparticles. Additionally, the influence of different temperatures, pressures, precursor ratios, surface ligands, bases, and core components in the synthesis was investigated with regard to the particle sizes and optical properties. As a result, a red shift of the emission and absorption maxima with increasing reaction temperature (100 to 220°C), pressure (1 to 25 bar), and different ratios of core components of alloyed semiconductor nanoparticles could be observed without a change of the particle size. An increase in particle size from 2.5 to 5 nm was only achieved by variation of the mercaptocarboxylic acid ligands in combination with the reaction time and used base. To get a first hint on the cytotoxic effects and cell uptake of the synthesized quantum dots, in vitro tests mesenchymal stem cells (MSCs) were carried out.

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

Changing Face of Wood Science in Modern Era: Contribution of Nanotechnology.

PubMed

Mishra, Pawan Kumar; Giagli, Kyriaki; Tsalagkas, Dimitrios; Mishra, Harshita; Talegaonkar, Sushma; Gryc, Vladimír; Wimmer, Rupert

2018-02-14

Wood science and nanomaterials science interact together in two different aspects; a) fabrication of lignocellulosic nanomaterials derived from wood and plant-based sources and b) surface or bulk wood modification by nanoparticles. In this review, we attempt to visualize the impact of nanoparticles on the wood coating and preservation treatments based on a thorough registration of the patent databases. The study was carried out as an overview of the scientifically most followed trends on nanoparticles utilization in wood science and wood protection depicted by recent universal filed patents. This review is exclusively targeted on the solid (timber) wood as a subject material. Utilization of mainly metal nanoparticles as photoprotection, antibacterial, antifungal, antiabrasive and functional component on wood modification treatments was found to be widely patented. Additionally, an apparent minimization in the emission of volatile organic compounds (VOCs) has been succeeded. Bulk wood preservation and more importantly, wood coating, splay the range of strengthening wood dimensional stability and biological degradation, against moisture absorption and fungi respectively. Nanoparticle materials have addressed various issues of wood science in a more efficient and environmental way than the traditional methods. Nevertheless, abundant tests and regulations are still needed before industrializing or recycling these products. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Computing Device Applications of Group IV Nanoparticle Spectroscopy

DTIC Science & Technology

2013-04-01

dependent on interband wavefunction symmetry. Second is the surface plasmon polariton (SPP) scattering lifetime. The SPP lifetime has two components...silicon nanoparticles for several minutes, then removed and allowed to air dry. The surface was then imaged using a scanning tunneling microscope. On...nominal q-dot boundary. This juxtaposition depends on particle effective masses and band curvatures.) SPP excitations require sufficient local charge

Harmonics distribution of iron oxide nanoparticles solutions under diamagnetic background

NASA Astrophysics Data System (ADS)

Saari, Mohd Mawardi; Che Lah, Nurul Akmal; Sakai, Kenji; Kiwa, Toshihiko; Tsukada, Keiji

2018-04-01

The static and dynamic magnetizations of low concentrated multi-core iron oxide nanoparticles solutions were investigated by a specially developed high-Tc Superconducting Quantum Interference Device (SQUID) magnetometer. The size distribution of iron oxide cores was determined from static magnetization curves concerning different concentrations. The simulated harmonics distribution was compared to the experimental results. Effect of the diamagnetic background from carrier liquid to harmonics distribution was investigated with respect to different intensity and position of peaks in the magnetic moment distribution using a numerical simulation. It was found that the diamagnetic background from carrier liquid of iron oxide nanoparticles affected the harmonics distribution as their concentration decreased and depending on their magnetic moment distribution. The first harmonic component was susceptible to the diamagnetic contribution of carrier liquid when the concentration was lower than 24 μg/ml. The second and third harmonics were affected when the peak position of magnetic moment distribution was smaller than m = 10-19 Am2 and the concentration was 10 ng/ml. A highly sensitive detection up to sub-nanogram of iron oxide nanoparticles in solutions can be achieved by utilizing second and third harmonic components.

The interplay of lung surfactant proteins and lipids assimilates the macrophage clearance of nanoparticles.

PubMed

Ruge, Christian A; Schaefer, Ulrich F; Herrmann, Jennifer; Kirch, Julian; Cañadas, Olga; Echaide, Mercedes; Pérez-Gil, Jesús; Casals, Cristina; Müller, Rolf; Lehr, Claus-Michael

2012-01-01

The peripheral lungs are a potential entrance portal for nanoparticles into the human body due to their large surface area. The fact that nanoparticles can be deposited in the alveolar region of the lungs is of interest for pulmonary drug delivery strategies and is of equal importance for toxicological considerations. Therefore, a detailed understanding of nanoparticle interaction with the structures of this largest and most sensitive part of the lungs is important for both nanomedicine and nanotoxicology. Astonishingly, there is still little known about the bio-nano interactions that occur after nanoparticle deposition in the alveoli. In this study, we compared the effects of surfactant-associated protein A (SP-A) and D (SP-D) on the clearance of magnetite nanoparticles (mNP) with either more hydrophilic (starch) or hydrophobic (phosphatidylcholine) surface modification by an alveolar macrophage (AM) cell line (MH-S) using flow cytometry and confocal microscopy. Both proteins enhanced the AM uptake of mNP compared with pristine nanoparticles; for the hydrophilic ST-mNP, this effect was strongest with SP-D, whereas for the hydrophobic PL-mNP it was most pronounced with SP-A. Using gel electrophoretic and dynamic light scattering methods, we were able to demonstrate that the observed cellular effects were related to protein adsorption and to protein-mediated interference with the colloidal stability. Next, we investigated the influence of various surfactant lipids on nanoparticle uptake by AM because lipids are the major surfactant component. Synthetic surfactant lipid and isolated native surfactant preparations significantly modulated the effects exerted by SP-A and SP-D, respectively, resulting in comparable levels of macrophage interaction for both hydrophilic and hydrophobic nanoparticles. Our findings suggest that because of the interplay of both surfactant lipids and proteins, the AM clearance of nanoparticles is essentially the same, regardless of different intrinsic surface properties.

Antimicrobial activity and physical characterization of silver nanoparticles green synthesized using nitrate reductase from Fusarium oxysporum.

PubMed

Gholami-Shabani, Mohammadhassan; Akbarzadeh, Azim; Norouzian, Dariush; Amini, Abdolhossein; Gholami-Shabani, Zeynab; Imani, Afshin; Chiani, Mohsen; Riazi, Gholamhossein; Shams-Ghahfarokhi, Masoomeh; Razzaghi-Abyaneh, Mehdi

2014-04-01

Nanostructures from natural sources have received major attention due to wide array of biological activities and less toxicity for humans, animals, and the environment. In the present study, silver nanoparticles were successfully synthesized using a fungal nitrate reductase, and their biological activity was assessed against human pathogenic fungi and bacteria. The enzyme was isolated from Fusarium oxysporum IRAN 31C after culturing on malt extract-glucose-yeast extract-peptone (MGYP) medium. The enzyme was purified by a combination of ultrafiltration and ion exchange chromatography on DEAE Sephadex and its molecular weight was estimated by gel filtration on Sephacryl S-300. The purified enzyme had a maximum yield of 50.84 % with a final purification of 70 folds. With a molecular weight of 214 KDa, it is composed of three subunits of 125, 60, and 25 KDa. The purified enzyme was successfully used for synthesis of silver nanoparticles in a way dependent upon NADPH using gelatin as a capping agent. The synthesized silver nanoparticles were characterized by X-ray diffraction, dynamic light scattering spectroscopy, and transmission and scanning electron microscopy. These stable nonaggregating nanoparticles were spherical in shape with an average size of 50 nm and a zeta potential of -34.3. Evaluation of the antimicrobial effects of synthesized nanoparticles by disk diffusion method showed strong growth inhibitory activity against all tested human pathogenic fungi and bacteria as evident from inhibition zones that ranged from 14 to 25 mm. Successful green synthesis of biologically active silver nanoparticles by a nitrate reductase from F. oxysporum in the present work not only reduces laborious downstream steps such as purification of nanoparticle from interfering cellular components, but also provides a constant source of safe biologically-active nanomaterials with potential application in agriculture and medicine.

General Synthetic Strategy for Libraries of Supported Multicomponent Metal Nanoparticles.

PubMed

Yang, Hui; Bradley, Siobhan J; Wu, Xin; Chan, Andrew; Waterhouse, Geoffrey I N; Nann, Thomas; Zhang, Jian; Kruger, Paul E; Ma, Shengqian; Telfer, Shane G

2018-04-18

Nanoparticles comprising three or more different metals are challenging to prepare. General methods that tackle this challenge are highly sought after as multicomponent metal nanoparticles display favorable properties in applications such as catalysis, biomedicine, and imaging. Herein, we report a practical and versatile approach for the synthesis of nanoparticles composed of up to four different metals. This method relies on the thermal decomposition of nanostructured composite materials assembled from platinum nanoparticles, a metal-organic framework (ZIF-8), and a tannic acid coordination polymer. The controlled integration of multiple metal cations (Ni, Co, Cu, Mn, Fe, and/or Tb) into the tannic acid shell of the precursor material dictates the composition of the final multicomponent metal nanoparticles. Upon thermolysis, the platinum nanoparticles seed the growth of the multicomponent metal nanoparticles via coalescence with the metallic constituents of the tannic acid coordination polymer. The nanoparticles are supported in the walls of hollow nitrogen-doped porous carbon capsules created by the decomposition of the organic components of the precursor. The capsules prevent sintering and detachment of the nanoparticles, and their porosity allows for efficient mass transport. To demonstrate the utility of producing a broad library of supported multicomponent metal nanoparticles, we tested their electrocatalytic performance toward the hydrogen evolution reaction and oxygen evolution reaction. We discovered functional relationships between the composition of the nanoparticles and their electrochemical activity and identified the PtNiCu and PtNiCuFe nanoparticles as particularly efficient catalysts. This highlights how to generate diverse libraries of multicomponent metal nanoparticles that can be synthesized and subsequently screened to identify high-performance materials for target applications.

Fabrication and characterization of copper oxide (CuO)–gold (Au)–titania (TiO{sub 2}) and copper oxide (CuO)–gold (Au)–indium tin oxide (ITO) nanowire heterostructures

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

Chopra, Nitin, E-mail: nchopra@eng.ua.edu; Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487; Shi, Wenwu

2014-10-15

Nanoscale heterostructures composed of standing copper oxide nanowires decorated with Au nanoparticles and shells of titania and indium tin oxide were fabricated. The fabrication process involved surfactant-free and wet-chemical nucleation of gold nanoparticles on copper oxide nanowires followed by a line-of-sight sputtering of titania or indium tin oxide. The heterostructures were characterized using high resolution electron microscopy, diffraction, and energy dispersive spectroscopy. The interfaces, morphologies, crystallinity, phases, and chemical compositions were analyzed. The process of direct nucleation of gold nanoparticles on copper oxide nanoparticles resulted in low energy interface with aligned lattice for both the components. Coatings of polycrystalline titaniamore » or amorphous indium tin oxide were deposited on standing copper oxide nanowire–gold nanoparticle heterostructures. Self-shadowing effect due to standing nanowire heterostructures was observed for line-of-sight sputter deposition of titania or indium tin oxide coatings. Finally, the heterostructures were studied using Raman spectroscopy and ultraviolet–visible spectroscopy, including band gap energy analysis. Tailing in the band gap energy at longer wavelengths (or lower energies) was observed for the nanowire heterostructures. - Highlights: • Heterostructures comprised of CuO nanowires coated with Au nanoparticles. • Au nanoparticles exhibited nearly flat and low energy interface with nanowire. • Heterostructures were further sputter-coated with oxide shell of TiO{sub 2} or ITO. • The process resulted in coating of polycrystalline TiO{sub 2} and amorphous ITO shell.« less

Electrochemical determination of dopamine and ascorbic acid at a novel gold nanoparticles distributed poly(4-aminothiophenol) modified electrode.

PubMed

Gopalan, Anantha Iyengar; Lee, Kwang-Pill; Manesh, Kalayil Manian; Santhosh, Padmanabhan; Kim, Jun Heon; Kang, Jae Soo

2007-03-15

A modified electrode is fabricated by embedding gold nanoparticles into a layer of electroactive polymer, poly(4-aminothiophenol) (PAT) on the surface of glassy carbon (GC) electrode. Cyclic voltammetry (CV) is performed to deposit PAT and concomitantly deposit Au nanoparticles. Field emission transmission electron microscopic image of the modified electrode, PAT-Au(nano)-ME, indicates the presence of uniformly distributed Au nanoparticles having the sizes of 8-10nm. Electrochemical behavior of the PAT-Au(nano)-ME towards detection of ascorbic acid (AA) and dopamine (DA) is studied using CV. Electrocatalytic determination of DA in the presence of fixed concentration of AA and vice versa, are studied using differential pulse voltammetry (DPV). PAT-Au(nano)-ME exhibits two well defined anodic peaks at the potential of 75 and 400mV for the oxidation of AA and DA, respectively with a potential difference of 325mV. Further, the simultaneous determination of AA and DA is studied by varying the concentration of AA and DA. PAT-Au(nano)-ME exhibits selectivity and sensitivity for the simultaneous determination of AA and DA without fouling by the oxidation products of AA or DA. PAT and Au nanoparticles provide synergic influence on the accurate electrochemical determination of AA or DA from a mixture having any one of the component (AA or DA) in excess. The practical analytical utilities of the PAT-Au(nano)-ME are demonstrated by the determination of DA and AA in dopamine hydrochloride injection and human blood serum samples.

Characterization of water based nanofluid for quench medium

NASA Astrophysics Data System (ADS)

Kresnodrianto; Harjanto, S.; Putra, W. N.; Ramahdita, G.; Yahya, S. S.; Mahiswara, E. P.

2018-04-01

Quenching has been a valuable method in steel hardening method especially in industrial scale. The hardenability of the metal alloys, the thickness of the component, and the geometry is some factors that can affect the choice of quench medium. Improper quench media can cause the material to become too brittle, suffers some geometric distortion, and undesirable residual stress that will cause some effect on the mechanical property and fracture mechanism of a component. Recently, nanofluid as a quench medium has been used for better quenching performance and has been studied using several different fluids and nanoparticles. Some of frequently used solvents include polymers, vegetable oils, and mineral oil, and nanoparticles frequently used include CuO, ZnO, and Alumina. In this research, laboratory-grade carbon powder were used as nanoparticle. Water was used as the fluid base in this research as the main observation focus. Carbon particles were obtain using a top-down method, whereas planetary ball mill was used to ground laboratory grade carbon powder to decrease the particle size. Milling speed and duration were set at 500 rpm and 15 hours. Field Emission Scanning Electron Microscope (FE-SEM), and Energy Dispersive X-Ray (EDX) measurement were carried out to determine the particle size, material identification, particle morphology, and surface change of samples. Nanofluid was created by mixing percentage of carbon nanoparticles with water using ultrasonic vibration for 280s. The carbon nanoparticle content in nanofluid quench mediums for this research were varied at 0.1%, 0.2%, 0.3%, 0.4, and 0.5 % volume. Furthermore, these mediums were used to quench JIS S45C or AISI 1045 carbon steel samples which austenized at 1000°C. Hardness testing and metallography observation were then conducted to further check the effect of different quench medium in steel samples. Preliminary characterizations showed that carbon particles dimension after milling was still in sub-micron stage, hundreds of nanometres to be precise. Therefore, the milling process parameters are needed to be optimized further.

Metal nanoparticle-graphene oxide composites: Photophysical properties and sensing applications

NASA Astrophysics Data System (ADS)

Murphy, Sean J.

Composite nanomaterials allow for attractive properties of multiple functional components to be combined. Fundamental understanding of the interaction between different nanomaterials, their surroundings, and nearby molecular species is pertinent for implementation into devices. Metal nanoparticles have been used for their optical properties in many applications including stained glass, cancer therapy, solar steam generation, surface enhanced Raman spectroscopy (SERS), and catalysis. Carbon-based nanomaterials such as graphene and carbon nanotubes show potential for a wide variety of applications including solar energy harvesting, chemical sensors, and electronics. Combining useful and in some cases new properties of composite nanomaterials offers exciting opportunities in fundamental science and device development. In this dissertation, I aim to address understanding photoinduced interaction between porphyrin and silver nanoparticles, inter-sheet interaction between stacked graphene oxide (GO) sheets in thin films, complexation of reduced GO with Raman active target molecule in SERS applications, and efficacy of graphene-metal nanoparticle composites for sensing applications. Molecule-metal nanoparticle composite material made up of photoactive porphyrin and silver nanoparticles was studied using various spectroscopic tools. UV-visible absorption and surface enhanced Raman spectroscopic results suggest formation of a charge-transfer complex for porphyrin-silver nanoparticle composite. Ultrafast transient absorption and fluorescence upconversion spectroscopies further corroborate electronic interaction by providing evidence for excited state electron transfer between porphyrin and silver nanoparticles. Understanding electronic interaction between adsorbed photoactive molecules and metal nanoparticles may be of use for applications in photocatalysis or light-energy harvesting. Graphene oxide (GO) thin films have been prepared and studied using transient absorption microscopy (TAM). Transient absorption microscopy correlated with atomic force microscope allows for the morphological properties of GO thin film to be related to optical properties, namely dynamics of photoexcited carriers in GO. Results suggest short-timescale (ps -- ˜1 ns) dynamics of charge carriers in GO are affected very little by interaction with the glass substrate on which GO is placed. Also, the stack thickness or number of stacked GO sheets does not play a large role in the short-timescale dynamics of GO charge carriers. GO or reduced GO (RGO)-silver nanoparticles composites were produced using different methods: (1) chemical reduction of silver ion precursor and (2) photocatalytic reduction of GO and silver ion using TiO2 nanoparticles. Optical and morphological properties of composites were studied using spectroscopy and electron microscopy revealing a degree of control in metal nanoparticle growth and loading on the surface of RGO. Nanocomposites were shown to be capable of complexing with or adsorbing target molecular species. Complexation and adsorption are corroborated with demonstration that the composite nanomaterials act as effective SERRS sensors taking advantage of localized surface plasmon resonance of metal nanoparticles and the ability of RGO to interact with molecular and ionic species.

Surface modification of nanoparticles enables selective evasion of phagocytic clearance by distinct macrophage phenotypes

NASA Astrophysics Data System (ADS)

Qie, Yaqing; Yuan, Hengfeng; von Roemeling, Christina A.; Chen, Yuanxin; Liu, Xiujie; Shih, Kevin D.; Knight, Joshua A.; Tun, Han W.; Wharen, Robert E.; Jiang, Wen; Kim, Betty Y. S.

2016-05-01

Nanomedicine is a burgeoning industry but an understanding of the interaction of nanomaterials with the immune system is critical for clinical translation. Macrophages play a fundamental role in the immune system by engulfing foreign particulates such as nanoparticles. When activated, macrophages form distinct phenotypic populations with unique immune functions, however the mechanism by which these polarized macrophages react to nanoparticles is unclear. Furthermore, strategies to selectively evade activated macrophage subpopulations are lacking. Here we demonstrate that stimulated macrophages possess higher phagocytic activities and that classically activated (M1) macrophages exhibit greater phagocytic capacity than alternatively activated (M2) macrophages. We show that modification of nanoparticles with polyethylene-glycol results in decreased clearance by all macrophage phenotypes, but importantly, coating nanoparticles with CD47 preferentially lowers phagocytic activity by the M1 phenotype. These results suggest that bio-inspired nanoparticle surface design may enable evasion of specific components of the immune system and provide a rational approach for developing immune tolerant nanomedicines.

Aluminosilicate nanoparticles for catalytic hydrocarbon cracking.

PubMed

Liu, Yu; Pinnavaia, Thomas J

2003-03-05

Aluminosilicate nanoparticles containing 9.0-20 nm mesopores were prepared through the use of protozeolitic nanoclusters as the inorganic precursor and starch as a porogen. The calcined, porogen-free composition containing 2 mol % aluminum exhibited the porosity, hydrothermal stability, and acidity needed for the cracking of very large hydrocarbons. In fact, the hydrothermal stability of the nanoparticles to pure steam at 800 degrees C, along with the cumene cracking activity, surpassed the analogous performance properties of ultrastable Y zeolite, the main catalyst component of commercial cracking catalysts. The remarkable hydrothermal stability and catalytic reactivity of the new nanoparticles are attributable to a unique combination of two factors, the presence of protozeolitic nanoclusters in the pore walls and the unprecedented pore wall thickness (7-15 nm). In addition, the excellent catalytic longevity of the nanoparticles is most likely facilitated by the small domain size of the nanoparticles that greatly improves access to the acid sites on the pore walls and minimizes the diffusion length of coke precursors out of the pores.

Deactivation of photocatalytically active ZnO nanoparticle and enhancement of its compatibility with organic compounds by surface-capping with organically modified silica

NASA Astrophysics Data System (ADS)

Cao, Zhi; Zhang, Zhijun

2011-02-01

Tetraethyl orthosilicate (TEOS) and dimethyldiethoxysilane (DEDMS) were used as co-precursors to prepare organically modified silica (ormosil) via sol-gel process. The resultant ormosil was adopted for surface-capping of ZnO nanoparticle, where methyl (organic functional group) and silica (inorganic component) were simultaneously introduced onto the surface of the nanoparticles for realizing dual surface-modification. The ormosil-capped ZnO nanoparticle showed strong hydrophobicity and good compatibility with organic phases, as well as effectively decreased photocatalytic activity and almost unchanged ultraviolet (UV)-shielding ability. More importantly, the comprehensive properties of ormosil-capped ZnO nanoparticle could be manipulated by adjusting the molar ratio of TEOS to DEDMS during sol-gel process. This should help to open a wider window to better utilizing the unique and highly attractive properties such as high UV-shielding ability and high-visible light transparency of ZnO nanoparticle in sunscreen cosmetics.

Repetitive heterocoagulation of oppositely charged particles for enhancement of magnetic nanoparticle loading into monodisperse silica particles.

PubMed

Matsumoto, Hideki; Nagao, Daisuke; Konno, Mikio

2010-03-16

Oppositely charged particles were repetitively heterocoagulated to fabricate highly monodisperse magnetic silica particles with high loading of magnetic nanoparticles. Positively charged magnetic nanoparticles prepared by surface modification with N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride (TSA) were used to heterocoagulate with silica particles under basic conditions to give rise to negative silica surface charge and prevent the oxidation of the magnetic nanoparticles. The resultant particles of silica core homogeneously coated with the magnetic nanoparticles were further coated with thin silica layer with sodium silicate in order to enhance colloidal stability and avoid desorption of the magnetic nanoparticles from the silica cores. Five repetitions of the heterocoagulation and the silica coating could increase saturation magnetization of the magnetic silica particles to 27.7 emu/g, keeping the coefficient of variation of particle sizes (C(V)) less than 6.5%. Highly homogeneous loading of the magnetic component was confirmed by measuring Fe-to-Si atomic ratios of individual particles with energy dispersive X-ray spectroscopy.

Workplace performance of a loose-fitting powered air purifying respirator during nanoparticle synthesis

NASA Astrophysics Data System (ADS)

Koivisto, Antti J.; Aromaa, Mikko; Koponen, Ismo K.; Fransman, Wouter; Jensen, Keld A.; Mäkelä, Jyrki M.; Hämeri, Kaarle J.

2015-04-01

Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 106 cm-3. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying respirators, while workers were coating components with TiO2 or Cu x O y nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 106 to 40 × 106 cm-3, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the respirator varied from 0.7 to 7.2 cm-3. However, on average, tidal breathing was assumed to increase the respirator concentration by 2.3 cm-3. The derived PPF exceeded 1.1 × 106, which is more than 40 × 103 times the respirator assigned protection factor. We were unable to measure clear differences in the PPF of respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying respirator provides very efficient protection against nanoparticle inhalation exposure if used properly.

Depositing laser-generated nanoparticles on powders for additive manufacturing of oxide dispersed strengthened alloy parts via laser metal deposition

NASA Astrophysics Data System (ADS)

Streubel, René; Wilms, Markus B.; Doñate-Buendía, Carlos; Weisheit, Andreas; Barcikowski, Stephan; Henrich Schleifenbaum, Johannes; Gökce, Bilal

2018-04-01

We present a novel route for the adsorption of pulsed laser-dispersed nanoparticles onto metal powders in aqueous solution without using any binders or surfactants. By electrostatic interaction, we deposit Y2O3 nanoparticles onto iron-chromium based powders and obtain a high dispersion of nano-sized particles on the metallic powders. Within the additively manufactured component, we show that the particle spacing of the oxide inclusion can be adjusted by the initial mass fraction of the adsorbed Y2O3 particles on the micropowder. Thus, our procedure constitutes a robust route for additive manufacturing of oxide dispersion-strengthened alloys via oxide nanoparticles supported on steel micropowders.

Delivery of RNA interference therapeutics using polycation-based nanoparticles.

PubMed

Howard, Kenneth Alan

2009-07-25

RNAi-based therapies are dependent on extracellular and intracellular delivery of RNA molecules for enabling target interaction. Polycation-based nanoparticles (or polyplexes) formed by self-assembly with RNA can be used to modulate pharmacokinetics and intracellular trafficking to improve the therapeutic efficacy of RNAi-based therapeutics. This review describes the application of polyplexes for extracellular and intracellular delivery of synthetic RNA molecules. Focus is given to routes of administration and silencing effects in animal disease models. The inclusion of functional components into the nanoparticle for controlling cellular trafficking and RNA release is discussed. This work highlights the versatile nature of polycation-based nanoparticles to fulfil the delivery requirements for RNA molecules with flexibility in design to evolve alongside an expanding repertoire of RNAi-based drugs.

Hyperdiffusive dynamics in Newtonian nanoparticle fluids [Hyperdiffusive dynamics in equilibrated nanoparticle fluids

DOE PAGES

Srivastava, Samanvaya; Agarwal, Praveen; Mangal, Rahul; ...

2015-09-24

Hyperdiffusive relaxations in soft glassy materials are typically associated with out-of-equilibrium states, and non-equilibrium physics and aging are often invoked in explaining their origins. Here, we report on hyperdiffusive motion in a model, equilibrium soft material comprised of single-component polymer-tethered-nanoparticles. In these materials, polymer mediated interactions lead to strong nanoparticle correlations, hyperdiffusive relaxations, and unusual variations of properties with temperature. Our experimental observations complement the current hypothesis that hyperdiffusive relaxations in soft materials require the material to exist in out–of–equilibrium states capable of driving structural rearrangements. Lastly, we propose alternatively that hyperdiffusive relaxations in our materials can arise naturally frommore » volume fluctuations brought about by equilibrium thermal forces.« less

Conductance oscillations in molecularly linked Au nanoparticle film-superconductor systems.

PubMed

Dunford, Jeffrey L; Dhirani, Al-Amin

2008-01-16

Charge transport across a disordered normal-superconductor (DN-S) interface was studied using a macroscopic, molecularly linked Au nanoparticle film as the DN component. Low-temperature conductance versus voltage and magnetic field exhibit zero-bias and zero-field peaks, respectively. Importantly, the latter typically exhibit superimposed oscillations. Such oscillations are rarely seen in other DN-S systems and are remarkable given their robustness in these macroscopic films and interfaces. A number of observations indicate that conductance peaks and oscillations arise due to a 'reflectionless tunnelling' process. Scattering length scales extracted from the data using a reflectionless tunnelling picture are consistent with literature values. Factors resulting in the observation of oscillations in this system are discussed.

Synthesis, characterization and toxicological evaluation of maltodextrin capped cadmium sulfide nanoparticles in human cell lines and chicken embryos

PubMed Central

2012-01-01

Background Semiconductor Quantum dots (QDs) have become quite popular thanks to their properties and wide use in biological and biomedical studies. However, these same properties entail new challenges in understanding, predicting, and managing potential adverse health effects following exposure. Cadmium and selenium, which are the major components of the majority of quantum dots, are known to be acutely and chronically toxic to cells and organisms. Protecting the core of nanoparticles can, to some degree, control the toxicity related to cadmium and selenium leakage. Results This study successfully synthesized and characterized maltodextrin coated cadmium sulfide semiconductor nanoparticles. The results show that CdS-MD nanoparticles are cytotoxic and embryotoxic. CdS-MD nanoparticles in low concentrations (4.92 and 6.56 nM) lightly increased the number of HepG2 cell. A reduction in MDA-MB-231 cells was observed with concentrations higher than 4.92 nM in a dose response manner, while Caco-2 cells showed an important increase starting at 1.64 nM. CdS-MD nanoparticles induced cell death by apoptosis and necrosis in MDA-MD-231 cells starting at 8.20 nM concentrations in a dose response manner. The exposure of these cells to 11.48-14.76 nM of CdS-MD nanoparticles induced ROS production. The analysis of cell proliferation in MDA-MB-231 showed different effects. Low concentrations (1.64 nM) increased cell proliferation (6%) at 7 days (p < 0.05). However, higher concentrations (>4.92 nM) increased cell proliferation in a dose response manner (15-30%) at 7 days. Exposures of chicken embryos to CdS-MD nanoparticles resulted in a dose-dependent increase in anomalies that, starting at 9.84 nM, centered on the heart, central nervous system, placodes, neural tube and somites. No toxic alterations were observed with concentrations of < 3.28 nM, neither in cells nor chicken embryos. Conclusions Our results indicate that CdS-MD nanoparticles induce cell death and alter cell proliferation in human cell lines at concentrations higher than 4.92 nM. We also demonstrated that they are embryotoxic. However, no toxic effects were observed with doses lower than 3.28 nM in neither cells nor chicken embryos. The CdS-MD nanoparticles used in this study can be potentially used in bio-imaging applications. However, further studies using mammalian species are required in order to discard more toxic effects. PMID:23270407

New Electrochemical Methods for Studying Nanoparticle Electrocatalysis and Neuronal Exocytosis

NASA Astrophysics Data System (ADS)

Cox, Jonathan T.

This dissertation presents the construction and application of micro and nanoscale electrodes for electroanalytical analysis. The studies presented herein encompass two main areas: electrochemical catalysis, and studies of the dynamics of single cell exocytosis. The first portion of this dissertation engages the use of Pt nanoelectrodes to study the stability and electrocatalytic properties of materials. A single nanoparticle electrode (SNPE) was fabricated by immobilizing a single Au nanoparticle on a Pt disk nanoelectrode via an amine-terminated silane cross linker. In this manner we were able to effectively study the electrochemistry and electrocatalytic activity of single Au nanoparticles and found that the electrocatalytic activity is dependent on nanoparticle size. This study can further the understanding of the structure-function relationship in nanoparticle based electrocatalysis. Further work was conducted to probe the stability of Pt nanoelectrodes under conditions of potential cycling. Pt based catalysts are known to deteriorate under such conditions due to losses in electrochemical surface area and Pt dissolution. By using Pt disk nanoelectrodes we were able to study Pt dissolution via steady-state voltammetry. We observed an enhanced dissolution rate and higher charge density on nanoelectrodes than that previously found on macro scale electrodes. The goal of the second portion of this dissertation is to develop new analytical methods to study the dynamics of exocytosis from single cells. The secretion of neurotransmitters plays a key role in neuronal communication, and our studies highlight how bipolar electrochemistry can be employed to enhance detection of neurotransmitters from single cells. First, we developed a theory to quantitatively characterize the voltammetric behavior of bipolar carbon fiber microelectrodes and secondly applied those principles to single cell detection. We showed that by simply adding an additional redox mediator to the back-fill solution of a carbon fiber microelectrode, there is a significant enhancement in detection. Additionally we used solid state nanopores to detect individual phospholipid vesicles in solution. Vesicles are key cellular components that play essential biological roles especially in neurotransmission. This work represents preliminary studies in detection and size determination from vesicles isolated from individual cells.

Chitosan nanoparticles/cellulose nanocrystals nanocomposites as a carrier system for the controlled release of repaglinide.

PubMed

Abo-Elseoud, Wafaa S; Hassan, Mohammad L; Sabaa, Magdy W; Basha, Mona; Hassan, Enas A; Fadel, Shaimaa M

2018-05-01

The aim of the present work was to study the use of cellulose nanocrystals (CNC) and chitosan nanoparticles (CHNP) for developing controlled-release drug delivery system of the anti-hyperglycemic drug Repaglinide (RPG). CNC was isolated from palm fruit stalks by sulfuric acid hydrolysis; the dimensions of the isolated nanocrystals were 86-237 nm in length and 5-7 nm in width. Simple and economic method was used for the fabrication of controlled release drug delivery system from CNC and CHNP loaded with RPG drug via ionic gelation of chitosan in the presence of CNC and RPG. The prepared systems showed high drug encapsulation efficiency of about ~98%. Chemical modification of CNC by oxidation to introduce carboxylic groups on their surface (OXCNC) was also carried out for further controlling of RPG release. Particles size analysis showed that the average size of CHNP was about 197 nm while CHNP/CNC/RPG or CHNP/OXCNC/RPG nanoparticles showed average size of 215-310 nm. Compatibility studies by Fourier transform infrared (FTIR) spectroscopy showed no chemical reaction between RPG and the system's components used. By studying the drug release kinetic, all the prepared RPG formulations followed Higuchi model, indicating that the drug released by diffusion through the nanoparticles polymeric matrix. Copyright © 2018 Elsevier B.V. All rights reserved.

Delivery of vincristine sulfate-conjugated gold nanoparticles using liposomes: a light-responsive nanocarrier with enhanced antitumor efficiency

PubMed Central

Liu, Ying; He, Man; Niu, Mengmeng; Zhao, Yiqing; Zhu, Yuanzhang; Li, Zhenhua; Feng, Nianping

2015-01-01

Rapid drug release at the specific site of action is still a challenge for antitumor therapy. Development of stimuli-responsive hybrid nanocarriers provides a promising strategy to enhance therapeutic effects by combining the unique features of each component. The present study explored the use of drug–gold nanoparticle conjugates incorporated into liposomes to enhance antitumor efficiency. A model drug, vincristine sulfate, was physically conjugated with gold nanoparticles and verified by UV-visible and fourier transform infrared spectroscopy, and differential scanning calorimetry. The conjugates were incorporated into liposomes by film dispersion to yield nanoparticles (113.4 nm) with light-responsive release properties, as shown by in vitro release studies. Intracellular uptake and distribution was studied in HeLa cells using transmission electron microscopy and confocal laser scanning microscopy. This demonstrated liposome internalization and localization in endosomal–lysosomal vesicles. Fluorescence intensity increased in cells exposed to UV light, indicating that this stimulated intracellular drug release; this finding was confirmed by quantitative analyses using flow cytometry. Antitumor efficacy was evaluated in HeLa cells, both in culture and in implants in vivo in nude mice. HeLa cell viability assays showed that light exposure enhanced liposome cytotoxicity and induction of apoptosis. Furthermore, treatment with the prepared liposomes coupled with UV light exposure produced greater antitumor effects in nude mice and reduced side effects, as compared with free vincristine sulfate. PMID:25960649

A combined spectroscopic, molecular docking and molecular dynamic simulation study on the interaction of quercetin with β-casein nanoparticles.

PubMed

Mehranfar, Fahimeh; Bordbar, Abdol-Khalegh; Parastar, Hadi

2013-10-05

The interaction of quercetin with β-casein nanoparticle micelle was studied at various temperatures in order to do a complete thermodynamic and molecular analysis on the binding process. The results of fluorescence studies showed the possibility of fluorescence energy transfer between excited tryptophan and quercetin. The determined values of critical transfers distance and the mean distance of ligand from Trp-143 residues in β-casein micelle represents a non-radiative energy transfer mechanism for quenching and the existence of a significant interaction between this flavonoid and β-casein nanoparticle. The equilibrium binding of quercetin with β-casein micelle at different temperatures was studied by using UV-Vis absorption spectroscopy. The chemometric analysis (principal component analysis (PCA) and multivariate curve resolution-alternating least squares (MCR-ALS) methods) on spectrophotometric data revealed the existence of two components in solution (quercetin and β-casein-quercetin complex) and resolved their pure concentration and spectral profiles. This information let us to calculate the equilibrium binding constant at various temperatures and the relevant thermodynamic parameters of interaction (enthalpy, entropy and Gibbs free energy) with low uncertainty. The negative values of entropy and enthalpy changes represent the predominate role of hydrogen binding and van der Waals interactions in the binding process. Docking calculations showed the probable binding site of quercetin is located in the hydrophobic core of β-casein where the quercetin molecule is lined by hydrophobic residues and make five hydrogen bonds and several van der Waals contacts with them. Moreover, molecular dynamic (MD) simulation results suggested that this flavonoid can interact with β-casein, without affecting the secondary structure of β-casein. Simulations, molecular docking and experimental data reciprocally supported each other. Copyright © 2013 Elsevier B.V. All rights reserved.

Formation of Sn–M (M=Fe, Al, Ni) alloy nanoparticles by DC arc-discharge and their electrochemical properties as anodes for Li-ion batteries

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

Gao, Song; Huang, Hao, E-mail: huanghao@dlut.edu.cn; Wu, Aimin

2016-10-15

A direct current arc-discharge method was applied to prepare the Sn–M (M=Fe, Al, Ni) bi-alloy nanoparticles. Thermodynamic is introduced to analyze the energy circumstances for the formation of the nanoparticles during the physical condensation process. The electrochemical properties of as-prepared Sn–M alloy nanoparticles are systematically investigated as anodes of Li-ion batteries. Among them, Sn–Fe nanoparticles electrode exhibits high Coulomb efficiency (about 71.2%) in the initial charge/discharge (257.9 mA h g{sup −1}/366.6 mA h g{sup −1}) and optimal cycle stability (a specific reversible capacity of 240 mA h g{sup −1} maintained after 20 cycles) compared with others. Large differences in themore » electrochemical behaviors indicate that the chemical composition and microstructure of the nanoparticles determine the lithium-ion storage properties and the long-term cyclic stability during the charge/discharge process. - Graphical abstract: The growth mechanism and electrochemical performance of Sn-based alloy nanoparticles. - Highlights: • Thermodynamic analyses of oxides on Sn-M nanoparticles surface. • The relationship between chemical components and electrochemical responses. • Sn-Fe nanoparticles show excellent electrode performance.« less

Magnetic nanoparticle detection method employing non-linear magnetoimpedance effects

NASA Astrophysics Data System (ADS)

Beato-López, J. J.; Pérez-Landazábal, J. I.; Gómez-Polo, C.

2017-04-01

In this work, a sensitive tool to detect magnetic nanoparticles (Fe3O4) based on a non-linear Giant Magnetoimpedance (GMI) effect is presented. The GMI sensor is designed with four nearly zero magnetostrictive ribbons connected in series and was analysed as a function of a constant external magnetic field and exciting frequency. The influence of the magnetic nanoparticles deposited on the ribbon surface was characterized using the first (fundamental) and second (non-linear) harmonics of the magnetoinductive voltage. The results show a clear enhancement of the sensor response in the high magnetic field region (H = 1.5 kA/m) as a consequence of the stray field generated by the magnetic nanoparticles on the GMI ribbons' surface. The highest sensitivity ratios are obtained for the non-linear component in comparison with the fundamental response. The results open a new research strategy in magnetic nanoparticle detection.

Single virus and nanoparticle size spectrometry by whispering-gallery-mode microcavities

NASA Astrophysics Data System (ADS)

Zhu, Jiangang; Kaya Özdemir, Şahin; He, Lina; Chen, Da-Ren; Yang, Lan

2011-08-01

Detecting and characterizing single nanoparticles and airborne viruses are of paramount importance for disease control and diagnosis, for environmental monitoring, and for understanding size dependent properties of nanoparticles for developing innovative products. Although single particle and virus detection have been demonstrated in various platforms, single-shot size measurement of each detected particle has remained a significant challenge. Here, we present a nanoparticle size spectrometry scheme for label-free, real-time and continuous detection and sizing of single Influenza A virions, polystyrene and gold nanoparticles using split whispering-gallery-modes (WGMs) in an ultra-high-Q resonator. We show that the size of each particle and virion can be measured as they continuously bind to the resonator one-by-one, eliminating the need for ensemble measurements, stochastic analysis or imaging techniques employed in previous works. Moreover, we show that our scheme has the ability to identify the components of particle mixtures.

Dynamic mechanical properties of hydroxyapatite/polyethylene oxide nanocomposites: characterizing isotropic and post-processing microstructures

NASA Astrophysics Data System (ADS)

Shofner, Meisha; Lee, Ji Hoon

2012-02-01

Compatible component interfaces in polymer nanocomposites can be used to facilitate a dispersed morphology and improved physical properties as has been shown extensively in experimental results concerning amorphous matrix nanocomposites. In this research, a block copolymer compatibilized interface is employed in a semi-crystalline matrix to prevent large scale nanoparticle clustering and enable microstructure construction with post-processing drawing. The specific materials used are hydroxyapatite nanoparticles coated with a polyethylene oxide-b-polymethacrylic acid block copolymer and a polyethylene oxide matrix. Two particle shapes are used: spherical and needle-shaped. Characterization of the dynamic mechanical properties indicated that the two nanoparticle systems provided similar levels of reinforcement to the matrix. For the needle-shaped nanoparticles, the post-processing step increased matrix crystallinity and changed the thermomechanical reinforcement trends. These results will be used to further refine the post-processing parameters to achieve a nanocomposite microstructure with triangulated arrays of nanoparticles.

Enrichment of plasma membrane proteins using nanoparticle pellicles: comparison between silica and higher density nanoparticles

PubMed Central

Choksawangkarn, Waeowalee; Kim, Sung-Kyoung; Cannon, Joe R.; Edwards, Nathan J.; Lee, Sang Bok; Fenselau, Catherine

2013-01-01

Proteomic and other characterization of plasma membrane proteins is made difficult by their low abundance, hydrophobicity, frequent carboxylation and dynamic population. We and others have proposed that underrepresentation in LC-MS/MS analysis can be partially compensated by enriching the plasma membrane and its proteins using cationic nanoparticle pellicles. The nanoparticles increase the density of plasma membrane sheets and thus enhance separation by centrifugation from other lysed cellular components. Herein we test the hypothesis that the use of nanoparticles with increased densities can provide enhanced enrichment of plasma membrane proteins for proteomic analysis. Multiple myeloma cells were grown and coated in suspension with three different pellicles of three different densities and both pellicle coated and uncoated suspensions analyzed by high-throughput LC-MS/MS. Enrichment was evaluated by the total number and the spectral counts of identified plasma membrane proteins. PMID:23289353

Lanthanide-based NMR: a tool to investigate component distribution in mixed-monolayer-protected nanoparticles.

PubMed

Guarino, Gaetano; Rastrelli, Federico; Scrimin, Paolo; Mancin, Fabrizio

2012-05-02

Gd(3+) ions, once bound to the monolayer of organic molecules coating the surface of gold nanoparticles, produce a paramagnetic relaxation enhancement (PRE) that broadens and eventually cancels the signals of the nuclear spins located nearby (within 1.6 nm distance). In the case of nanoparticles coated with mixed monolayers, the signals arising from the different coating molecules experience different PRE, depending on their distance from the binding site. As a consequence, observation of the signal broadening patterns provides direct information on the monolayer organization. © 2012 American Chemical Society

Ultrasonic activated efficient synthesis of chromenes using amino-silane modified Fe3O4 nanoparticles: A versatile integration of high catalytic activity and facile recovery

NASA Astrophysics Data System (ADS)

Safari, Javad; Zarnegar, Zohre

2014-08-01

An efficient synthesis of 2-amino-4H-chromenes is achieved by one pot three component coupling reaction of aldehyde, malononitrile, and resorcinol using amino-silane modified Fe3O4 nanoparticles (MNPs-NH2) heterogeneous nanocatalyst under sonic condition. The attractive advantages of the present process are mild reaction conditions, short reaction times, easy isolation of products, good yields and simple operational procedures. Combination of the advantages of ultrasonic irradiation and magnetic nanoparticles provides important methodology to carry out catalytic transformations.

Detection and quantification of angiogenesis in experimental valve disease with integrin-targeted nanoparticles and 19-fluorine MRI/MRS

PubMed Central

Waters, Emily A; Chen, Junjie; Allen, John S; Zhang, Huiying; Lanza, Gregory M; Wickline, Samuel A

2008-01-01

Background Angiogenesis is a critical early feature of atherosclerotic plaque development and may also feature prominently in the pathogenesis of aortic valve stenosis. It has been shown that MRI can detect and quantify specific molecules of interest expressed in cardiovascular disease and cancer by measuring the unique fluorine signature of appropriately targeted perfluorocarbon (PFC) nanoparticles. In this study, we demonstrated specific binding of ανβ3 integrin targeted nanoparticles to neovasculature in a rabbit model of aortic valve disease. We also showed that fluorine MRI could be used to detect and quantify the development of neovasculature in the excised aortic valve leaflets. Methods New Zealand White rabbits consumed a cholesterol diet for ~180 days and developed aortic valve thickening, inflammation, and angiogenesis mimicking early human aortic valve disease. Rabbits (n = 7) were treated with ανβ3 integrin targeted PFC nanoparticles or control untargeted PFC nanoparticles (n = 6). Competitive inhibition in vivo of nanoparticle binding (n = 4) was tested by pretreatment with targeted nonfluorinated nanoparticles followed 2 hours later by targeted PFC nanoparticles. 2 hours after treatment, aortic valves were excised and 19F MRS was performed at 11.7T. Integrated 19F spectral peaks were compared using a one-way ANOVA and Hsu's MCB (multiple comparisons with the best) post hoc t test. In 3 additional rabbits treated with ανβ3 integrin targeted PFC nanoparticles, 19F spectroscopy was performed on a 3.0T clinical scanner. The presence of angiogenesis was confirmed by immunohistochemistry. Results Valves of rabbits treated with targeted PFC nanoparticles had 220% more fluorine signal than valves of rabbits treated with untargeted PFC nanoparticles (p < 0.001). Pretreatment of rabbits with targeted oil-based nonsignaling nanoparticles reduced the fluorine signal by 42% due to competitive inhibition, to a level not significantly different from control animals. Nanoparticles were successfully detected in all samples scanned at 3.0T. PECAM endothelial staining and ανβ3 integrin staining revealed the presence of neovasculature within the valve leaflets. Conclusion Integrin-targeted PFC nanoparticles specifically detect early angiogenesis in sclerotic aortic valves of cholesterol fed rabbits. These techniques may be useful for assessing atherosclerotic components of preclinical aortic valve disease in patients and could assist in defining efficacy of medical therapies. PMID:18817557

Synthesis of Magnetite Nanoparticles and Its Application As Electrode Material for the Electrochemical Oxidation of Methanol

NASA Astrophysics Data System (ADS)

Shah, Muhammad Tariq; Balouch, Aamna; Panah, Pirah; Rajar, Kausar; Mahar, Ali Muhammad; Khan, Abdullah; Jagirani, Muhammad Saqaf; Khan, Humaira

2018-06-01

In this study, magnetite (Fe3O4) nanoparticles were synthesized by a simple and facile chemical co-precipitation method at ambient laboratory conditions. The synthesized Fe3O4 nanostructures were characterized for their morphology, size, crystalline structure and component analysis using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, x-ray diffraction and electron dispersive x-ray spectroscopy. The Fe3O4 nanoparticles showed semi-spherical geometry with an average particle diameter up to 14 nm. The catalytic properties of Fe3O4 nanoparticles were evaluated for electrochemical oxidation of methanol. For this purpose, the magnetite NPs were coated on the surface of an indium tin oxide (ITO) electrode and used as a working electrode in the electrochemical oxidation of methanol. The effect of potential scan rate, the concentration of methanol, the volume of electrolyte and catalyst (Fe3O4 NPs) deposition volume was studied to get high peak current densities for methanol oxidation. The stability and selectivity of the fabricated electrode (Fe3O4/ITO) were also assessed during the electrochemical process. This study revealed that the Fe3O4/ITO electrode was highly stable and selective towards methanol electrochemical oxidation in basic (KOH) media. Bare ITO and Fe3O4 NPs modified glassy (Fe3O4/GCE) electrodes were also tested in the electro-oxidation study of methanol, but their peak current density responses were very low as compared to the Fe3O4/ITO electrode, which showed high electrocatalytic activity towards methanol oxidation under similar conditions. We hope that Fe3O4 nanoparticles (NPs) will be an alternative for methanol oxidation as compared to the expensive noble metals (Pt, Au, and Pd) for energy generation processes.

Evaluation of the thermodynamic properties of hydrated metal oxide nanoparticles by INS techniques

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

Spencer, Elinor; Ross, Dr. Nancy; Parker, Stewart F.

2013-01-01

In this contribution we will present a detailed methodology for the elucidation of the following aspects of the thermodynamic properties of hydrated metal oxide nanoparticles from high-resolution, low-temperature inelastic neutron scattering (INS) data: (i) the isochoric heat capacity and entropy of the hydration layers both chemi- and physisorbed to the particle surface; (ii) the magnetic contribution to the heat capacity of the nanoparticles. This will include the calculation of the vibrational density of states (VDOS) from the raw INS spectra, and the subsequent extraction of the thermodynamic data from the VDOS. This technique will be described in terms of amore » worked example namely, cobalt oxide (Co3O4 and CoO). To complement this evaluation of the physical properties of metal oxide nanoparticle systems, we will emphasise the importance of high-resolution, high-energy INS for the determination of the structure and dynamics of the water species, namely molecular (H2O) and dissociated water (OH, hydroxyl), confined to the oxide surfaces. For this component of the chapter we will focus on INS investigations of hydrated isostructural rutile (a-TiO2) and cassiterite (SnO2) nanoparticles. We will complete this discussion of nanoparticle analysis by including an appraisal of the INS instrumentation employed in such studies with particular focus on TOSCA [ISIS, Rutherford Appleton Laboratory (RAL), U.K.] and the newly developed spectrometer SEQUOIA [SNS, Oak Ridge National Laboratory (ORNL), U.S.A].« less

Synergistic effect of the combination of triethylene-glycol modified Fe3O4 nanoparticles and ultrasound wave on MCF-7 cells

NASA Astrophysics Data System (ADS)

Ebrahimi Fard, Ali; Zarepour, Atefeh; Zarrabi, Ali; Shanei, Ahmad; Salehi, Hossein

2015-11-01

Cancer is a group of disease characterized by uncontrolled growth and spread of abnormal cells in the body. The clinical treatments for cancer include surgery, chemotherapy and radiotherapy. Currently, employing new approaches for treatment has attracted more attentions. One of these approaches is sonodynamic therapy, which is an analogous approach based on the synergistic effect of ultrasound and a chemical component referred to as sonosensitizer. Recent years applications of nanotechnology have witnessed a tremendous expansion of research in medicine especially in treatment of cancers. The combination of sonodynamic therapy and nanotechnology can introduce a new way for cancer therapy. In this study, we used therapeutic ultrasonic waves with intensity of 1 MHz and different concentrations of Fe3O4 nanoparticles, as sonosensitizer, to investigate their combination effect on MCF-7 cell line. Briefly, we divided cells into four different groups; control, cells which got in touch with nanoparticles, cells that with exposure to ultrasound waves and cells which were influenced with combination of nanoparticles and ultrasonic waves. Finally, cell viability assay was used for detection of cytotoxicity effects. Experimental results revealed a significant decrease in viability of cells, which were affected by the combined action of ultrasound field and Fe3O4 nanoparticles, compared to the separate exposure of Fe3O4 nanoparticles or ultrasonic field. The synergic effect of ultrasound waves and Fe ions might be due to the production of toxic free radicals.

Depot formulation of vasoactive intestinal peptide by protamine-based biodegradable nanoparticles.

PubMed

Wernig, Karin; Griesbacher, Martin; Andreae, Fritz; Hajos, Franz; Wagner, Julian; Mosgoeller, Wilhelm; Zimmer, Andreas

2008-09-10

Drug delivery of protein and peptide-based drugs, which represent a growing and important therapeutic class, is hampered by these drugs' very short half-lives. High susceptibility towards enzymatic degradation necessitates frequent drug administration followed by poor adherence to therapy. Among these drugs is vasoactive intestinal peptide (VIP), a potent systemic and pulmonary vasodilator, which is a promising drug for the treatment of idiopathic pulmonary arterial hypertension (IPAH). Encapsulation of VIP into the nanoparticle matrix of biodegradable protamine-oligonucleotide nanoparticles (proticles) protects the peptide against rapid enzymatic degradation. Additionally, the nanoparticle matrix will be able to sustain drug release. Proticles consist of 18mer non-sense oligonucleotides and protamine, a polycationic arginine-rich peptide. VIP encapsulation occurs during self-assembly of the components. Within the present study, we evaluate nanoparticle size (hydrodynamic diameter) and zeta potential of VIP-loaded proticles as well as encapsulation efficiency and VIP release. Further, the pharmacological VIP response of "encapsulated VIP" is investigated using an ex vivo lung arterial model system. We found satisfying encapsulation efficiency (up to 80%), VIP release (77-87%), and an appropriate nanoparticle size (177-251 nm). Investigations on rat pulmonary arteries showed a modified VIP response of proticle-associated VIP. We noted differences in the profile of artery relaxation where VIP proticles lead to a 20-30% lower relaxation maximum than aqueous VIP solutions followed by prolonged vasodilatation. Our data indicate that proticles could be a feasible drug delivery system for a pulmonary VIP depot formulation.

Proton exchange membranes for application in fuel cells: grafted silica/SPEEK nanocomposite elaboration and characterization.

PubMed

Reinholdt, Marc X; Kaliaguine, Serge

2010-07-06

Hydrogen technologies and especially fuel cells are key components in the battle to find alternate sources of energy to the highly polluting and economically constraining fossil fuels in an aim to preserve the environment. The present paper shows the synthesis of surface functionalized silica nanoparticles, which are used to prepare grafted silica/SPEEK nanocomposite membranes. The nanoparticles are grafted either with hexadecylsilyl or aminopropyldimethylsilyl moieties or both. The synthesized particles are analyzed using XRD, NMR, TEM, and DLS to collect information on the nature of the particles and the functional groups, on the particle sizes, and on the hydrophilic/hydrophobic character. The composite membranes prepared using the synthesized particles and two SPEEK polymers with sulfonation degrees of 69.4% and 85.0% are characterized for their proton conductivity and water uptake properties. The corresponding curves are very similar for the composites prepared with both polymers and the nanoparticles bearing the two functional groups. The composites prepared with the nanoparticles bearing solely the aminopropyldimethylsilyl moiety exhibit lower conductivity and water uptake, possibly due to higher interaction of the polymer sulfonic acid sites with the amine groups. The composites prepared with the nanoparticles bearing solely the hexadecylsilyl moiety were not further investigated because of very high particles segregation. A study of the proton conductivity as a function of temperature was performed on selected membranes and showed that nanocomposites made with nanoparticles bearing both functional moieties have a higher conductivity at higher temperatures.

Bacterial nanometric amorphous Fe-based oxide: a potential lithium-ion battery anode material.

PubMed

Hashimoto, Hideki; Kobayashi, Genki; Sakuma, Ryo; Fujii, Tatsuo; Hayashi, Naoaki; Suzuki, Tomoko; Kanno, Ryoji; Takano, Mikio; Takada, Jun

2014-04-23

Amorphous Fe(3+)-based oxide nanoparticles produced by Leptothrix ochracea, aquatic bacteria living worldwide, show a potential as an Fe(3+)/Fe(0) conversion anode material for lithium-ion batteries. The presence of minor components, Si and P, in the original nanoparticles leads to a specific electrode architecture with Fe-based electrochemical centers embedded in a Si, P-based amorphous matrix.

Role of silver nanoparticles (AgNPs) on the cardiovascular system.

PubMed

Gonzalez, Carmen; Rosas-Hernandez, Hector; Ramirez-Lee, Manuel Alejandro; Salazar-García, Samuel; Ali, Syed F

2016-03-01

With the advent of nanotechnology, the use and applications of silver nanoparticles (AgNPs) have increased, both in consumer products as well as in medical devices. However, little is known about the effects of these nanoparticles on human health, more specific in the cardiovascular system, since this system represents an important route of action in terms of distribution, bioaccumulation and bioavailability of the different circulating substances in the bloodstream. A collection of studies have addressed the effects and applications of different kinds of AgNPs (shaped, sized, coated and functionalized) in several components of the cardiovascular system, such as endothelial cells, isolated vessels and organs as well as integrative animal models, trying to identify the underlying mechanisms involved in their actions, to understand their implication in the field of biomedicine. The purpose of the present review is to summarize the most relevant studies to date of AgNPs effects in the cardiovascular system and provide a broader picture of the potential toxic effects and exposure risks, which in turn will allow pointing out the directions of further research as well as new applications of these versatile nanomaterials.

In Vivo PET Imaging of HDL in Multiple Atherosclerosis Models.

PubMed

Pérez-Medina, Carlos; Binderup, Tina; Lobatto, Mark E; Tang, Jun; Calcagno, Claudia; Giesen, Luuk; Wessel, Chang Ho; Witjes, Julia; Ishino, Seigo; Baxter, Samantha; Zhao, Yiming; Ramachandran, Sarayu; Eldib, Mootaz; Sánchez-Gaytán, Brenda L; Robson, Philip M; Bini, Jason; Granada, Juan F; Fish, Kenneth M; Stroes, Erik S G; Duivenvoorden, Raphaël; Tsimikas, Sotirios; Lewis, Jason S; Reiner, Thomas; Fuster, Valentín; Kjær, Andreas; Fisher, Edward A; Fayad, Zahi A; Mulder, Willem J M

2016-08-01

The goal of this study was to develop and validate a noninvasive imaging tool to visualize the in vivo behavior of high-density lipoprotein (HDL) by using positron emission tomography (PET), with an emphasis on its plaque-targeting abilities. HDL is a natural nanoparticle that interacts with atherosclerotic plaque macrophages to facilitate reverse cholesterol transport. HDL-cholesterol concentration in blood is inversely associated with risk of coronary heart disease and remains one of the strongest independent predictors of incident cardiovascular events. Discoidal HDL nanoparticles were prepared by reconstitution of its components apolipoprotein A-I (apo A-I) and the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine. For radiolabeling with zirconium-89 ((89)Zr), the chelator deferoxamine B was introduced by conjugation to apo A-I or as a phospholipid-chelator (1,2-distearoyl-sn-glycero-3-phosphoethanolamine-deferoxamine B). Biodistribution and plaque targeting of radiolabeled HDL were studied in established murine, rabbit, and porcine atherosclerosis models by using PET combined with computed tomography (PET/CT) imaging or PET combined with magnetic resonance imaging. Ex vivo validation was conducted by radioactivity counting, autoradiography, and near-infrared fluorescence imaging. Flow cytometric assessment of cellular specificity in different tissues was performed in the murine model. We observed distinct pharmacokinetic profiles for the two (89)Zr-HDL nanoparticles. Both apo A-I- and phospholipid-labeled HDL mainly accumulated in the kidneys, liver, and spleen, with some marked quantitative differences in radioactivity uptake values. Radioactivity concentrations in rabbit atherosclerotic aortas were 3- to 4-fold higher than in control animals at 5 days' post-injection for both (89)Zr-HDL nanoparticles. In the porcine model, increased accumulation of radioactivity was observed in lesions by using in vivo PET imaging. Irrespective of the radiolabel's location, HDL nanoparticles were able to preferentially target plaque macrophages and monocytes. (89)Zr labeling of HDL allows study of its in vivo behavior by using noninvasive PET imaging, including visualization of its accumulation in advanced atherosclerotic lesions. The different labeling strategies provide insight on the pharmacokinetics and biodistribution of HDL's main components (i.e., phospholipids, apo A-I). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Nanoscaling laws of magnetic nanoparticles and their applicabilities in biomedical sciences.

PubMed

Jun, Young-Wook; Seo, Jung-Wook; Cheon, Jinwoo

2008-02-01

Magnetic nanoparticles, which exhibit a variety of unique magnetic phenomena that are drastically different from those of their bulk counterparts, are garnering significant interest since these properties can be advantageous for utilization in a variety of applications ranging from storage media for magnetic memory devices to probes and vectors in the biomedical sciences. In this Account, we discuss the nanoscaling laws of magnetic nanoparticles including metals, metal ferrites, and metal alloys, while focusing on their size, shape, and composition effects. Their fundamental magnetic properties such as blocking temperature (Tb), spin life time (tau), coercivity (Hc), and susceptibility (chi) are strongly influenced by the nanoscaling laws, and as a result, these scaling relationships can be leveraged to control magnetism from the ferromagnetic to the superparamagnetic regimes. At the same time, they can be used in order to tune magnetic values including Hc, chi, and remanence (Mr). For example, life time of magnetic spin is directly related to the magnetic anisotropy energy (KuV) and also the size and volume of nanoparticles. The blocking temperature (Tb) changes from room temperature to 10 K as the size of cobalt nanoparticles is reduced from 13 to 2 nm. Similarly, H c is highly susceptible to the anisotropy of nanoparticles, while saturation magnetization is directly related to the canting effects of the disordered surface magnetic spins and follows a linear relationship upon plotting of ms (1/3) vs r(-1). Therefore, the nanoscaling laws of magnetic nanoparticles are important not only for understanding the behavior of existing materials but also for developing novel nanomaterials with superior properties. Since magnetic nanoparticles can be easily conjugated with biologically important constituents such as DNA, peptides, and antibodies, it is possible to construct versatile nano-bio hybrid particles, which simultaneously possess magnetic and biological functions for biomedical diagnostics and therapeutics. As demonstrated in this Account, nanoscaling laws for magnetic components are found to be critical to the design of optimized magnetic characteristics of hybrid nanoparticles and their enhanced applicability in the biomedical sciences including their utilizations as contrast enhancement agents for magnetic resonance imaging (MRI), ferromagnetic components for nano-bio hybrid structures, and translational vectors for magnetophoretic sensing of biological species. In particular, systematic modulation of saturation magnetization of nanoparticle probes is important to maximize MR contrast effects and magnetic separation of biological targets.

Characterization of oil based nanofluid for quench medium

NASA Astrophysics Data System (ADS)

Mahiswara, E. P.; Harjanto, S.; Putra, W. N.; Ramahdita, G.; Yahya, S. S.; Kresnodrianto

2018-01-01

The choice of quench medium depends on the hardenability of the metal alloy, the thickness of the component, and the geometry of the component. Some of these will determine the cooling rate required to obtain the desired microstructure and material properties. Improper quench media will cause the material to become brittle, suffers from geometric distortion, or having a high undesirable residual stresses in the components. In heat treatment industries, oil and water are frequently used as the quench media. Recently, nanofluid as a quench medium has also been studied using several different fluids as the solvent. Examples of frequently used solvents include polymers, vegetable oils, and mineral oil. In this research, laboratory-grade carbon powder were used as nanoparticle. Oil was used as the fluid base in this research as the main observation focus. To obtain nanoscale carbon particles, planetary ball mill was used to ground laboratory grade carbon powder to decrease the particle size. This method was used to lower the cost for nanoparticle synthesis. Milling speed and duration were set at 500 rpm and 15 hours. Field Emission Scanning Electron Microscope (FE-SEM), and Energy Dispersive X-Ray (EDX) measurement were carried out to determine the particle size, material identification, particle morphology, and surface change of samples. The carbon nanoparticle content in nanofluid quench mediums for this research were varied at 0.1%, 0.2%, 0.3%, 0.4, and 0.5 % volume. Furthermore, these mediums were used to quench JIS S45C or AISI 1045 carbon steel samples which annealed at 1000°C. Hardness testing and metallography observation were then conducted to further examine the effect of different quench medium in steel samples.

Inbuilt potential of YEM medium and its constituents to generate Ag/Ag₂O nanoparticles.

PubMed

Yamal, G; Sharmila, P; Rao, K S; Pardha-Saradhi, P

2013-01-01

We discovered that Yeast Extract Mannitol (YEM) medium possessed immense potential to generate silver nanoparticles from AgNO3 upon autoclaving, which was evident from (i) alteration in color of the medium; (ii) peak at ∼410 nm in UV-Vis spectrum due to surface plasmon resonance specific to silver nanoparticles; and (iii) TEM investigations. TEM coupled with EDX confirmed that distinct nanoparticles were composed of silver. Yeast extract and mannitol were key components of YEM medium responsible for the formation of nanoparticles. PXRD analysis indicated crystalline geometry and Ag/Ag2O phases in nanoparticles generated with YEM medium, yeast extract and mannitol. Our investigations also revealed that both mannitol and yeast extract possessed potential to convert ∼80% of silver ions in 0.5 mM AgNO3 to nanoparticles, on autoclaving for 30 min at 121°C under a pressure of 1.06 kg/cm(2). Addition of filter sterilized AgNO3 under ambient conditions to pre-autoclaved YEM medium and yeast extract brought about color change due to the formation of silver nanoparticles, but required prolonged duration. In general, even after 72 h intensity of color was significantly less than that recorded following autoclaving. Silver nanoparticles formed at room temperature were more heterogeneous compared to that obtained upon autoclaving. In summary, our findings demonstrated that (i) YEM medium and its constituents promote synthesis of silver nanoparticles; and (ii) autoclaving enhances rapid synthesis of silver nanoparticles by YEM medium, yeast extract and mannitol.

Photothermal nanoparticles as molecular specificity agents in interferometric phase microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Shaked, Natan T.

2017-02-01

I review our latest advances in wide-field interferometric imaging of biological cells with molecular specificity, obtained by time-modulated photothermal excitation of gold nanoparticles. Heat emitted from the nanoparticles affects the measured phase signal via both the nanoparticle surrounding refractive-index and thickness changes. These nanoparticles can be bio-functionalized to bind certain biological cell components; thus, they can be used for biomedical imaging with molecular specificity, as new nanoscopy labels, and for photothermal therapy. Predicting the ideal nanoparticle parameters requires a model that computes the thermal and phase distributions around the particle, enabling more efficient phase imaging of plasmonic nanoparticles, and sparing trial and error experiments of using unsuitable nanoparticles. We thus developed a new model for predicting phase signatures from photothermal nanoparticles with arbitrary parameters. We also present a dual-modality technique based on wide-field photothermal interferometric phase imaging and simultaneous ablation to selectively deplete specific cell populations labelled by plasmonic nanoparticles. We experimentally demonstrated our ability to detect and specifically ablate in vitro cancer cells over-expressing epidermal growth factor receptors (EGFRs), labelled with plasmonic nanoparticles, in the presence of either EGFR under-expressing cancer cells or white blood cells. This demonstration established an initial model for depletion of circulating tumour cells in blood. The proposed system is able to image in wide field the label-free quantitative phase profile together with the photothermal phase profile of the sample, and provides the ability of both detection and ablation of chosen cells after their selective imaging.

Preparation of PbS Nanoparticles by Phase-Transfer Method and Application to Pb2+-Selective Electrode Based on PVC Membrane

PubMed Central

Song, Weihong; Wu, Chunhui; Yin, Hongzong; Liu, Xiaoyan; Sa, Panpan; Hu, Jinyang

2008-01-01

A novel approach to prepare homogeneous PbS nanoparticles by phase-transfer method was developed. The preparatory conditions were studied in detail, and the nanoparticles were characterized by transmission electron microscopy (TEM) and UV-vis spectroscopy. Then a novel lead ion-selective electrode of polyvinyl chloride (PVC) membrane based on these lead sulfide nanoparticles was prepared, and the optimum ratio of components in the membrane was determined. The results indicated that the sensor exhibited a wide concentration range of 1.0×10−5 to 1.0×10−2 mol.L−1. The response time of the electrode was about 10 s, and the optimal pH in which the electrode could be used was from 3.0 to 7.0. Selectivity coefficients indicated that the electrode was selective to the primary ion over the interfering ion. The electrode can be used for at least 3 months without any divergence in potential. It was successfully applied to directly determine lead ions in solution and used as an indicator electrode in potentiometric titration of lead ions with EDTA. PMID:19112518

Effect of CuO nanolubricant on compressor characteristics and performance of LPG based refrigeration cycle: experimental investigation

NASA Astrophysics Data System (ADS)

Kumar, Ravinder; Singh, Jagdev; Kundal, Pankaj

2018-05-01

Refrigeration, Ventilation and Air Conditioning system is the largest reason behind the increasing demand of energy consumption in the world and saving that energy through some innovative methods becomes a large issue for the researchers. Compressor is a primary component of the refrigeration cycle. The application of nanoparticles in refrigeration cycle overcomes the energy consumption issue by improving the compressor suction and discharge characteristics. In this paper, an experimental study is carried out to investigate the effect of copper oxide (CuO) nanoparticles on different parameters of the refrigeration cycle. CuO particles are appended with the system refrigerant through lubricating oil of the compressor. Further, the viscosity measurements and friction coefficient analysis of compressor lubricant for different fractions of nanoparticles has been investigated. The results showed that both the suction and discharge characteristics of the compressor were enhanced with the utilization of nanolubricant in LPG based refrigeration cycle. Nanoparticles additive in lubricant increases the viscosity which lead to a significant decrease in friction coefficient. The COP of the cycle was improved by 46%, as the energy consumption of the compressor was decreased by 7%.

Fabrication of highly hydrophobic two-component thermosetting polyurethane surfaces with silica nanoparticles

NASA Astrophysics Data System (ADS)

Yang, Guang; Song, Jialu; Hou, Xianghui

2018-05-01

Highly hydrophobic thermosetting polyurethane (TSU) surfaces with micro-nano hierarchical structures were developed by a simple process combined with sandpaper templates and nano-silica embellishment. Sandpapers with grit sizes varying from 240 to 7000 grit were used to obtain micro-scale roughness on an intrinsic hydrophilic TSU surface. The surface wettability was investigated by contact angle measurement. It was found that the largest contact angle of the TSU surface without nanoparticles at 102 ± 3° was obtained when the template was 240-grit sandpaper and the molding progress started after 45 min curing of TSU. Silica nanoparticles modified with polydimethylsiloxane were scattered onto the surfaces of both the polymer and the template to construct the desirable nanostructures. The influences of the morphology, surface composition and the silica content on the TSU surface wettability were studied by scanning electron microscopy (SEM), attenuated total reflection (ATR) infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The surface of the TSU/SiO2 nanocomposites containing 4 wt% silica nanoparticles exhibited a distinctive dual-scale structure and excellent hydrophobicity with the contact angle above 150°. The mechanism of wettability was also discussed by Wenzel model and Cassie-Baxter model.

Global gene response in Saccharomyces cerevisiae exposed to silver nanoparticles.

PubMed

Niazi, Javed H; Sang, Byoung-In; Kim, Yeon Seok; Gu, Man Bock

2011-08-01

Silver nanoparticles (AgNPs), exhibiting a broad size range and morphologies with highly reactive facets, which are widely applicable in real-life but not fully verified for biosafety and ecotoxicity, were subjected to report transcriptome profile in yeast Saccharomyces cerevisiae. A large number of genes accounted for ∼3% and ∼5% of the genome affected by AgNPs and Ag-ions, respectively. Principal component and cluster analysis suggest that the different physical forms of Ag were the major cause in differential expression profile. Among 90 genes affected by both AgNPs and Ag-ions, metalloprotein mediating high resistance to copper (CUP1-1 and CUP1-2) were strongly induced by AgNPs (∼45-folds) and Ag-ions (∼22-folds), respectively. A total of 17 genes, responsive to chemical stimuli, stress, and transport processes, were differentially induced by AgNPs. The differential expression was also seen with Ag-ions that affected 73 up- and 161 down-regulating genes, and most of these were involved in ion transport and homeostasis. This study provides new information on the knowledge for impact of nanoparticles on living microorganisms that can be extended to other nanoparticles.

Biocompatible medical implant materials with binding sites for a biodegradable drug-delivery system

PubMed Central

Al-Dubai, Haifa; Pittner, Gisela; Pittner, Fritz; Gabor, Franz

2011-01-01

Feasibility studies have been carried out for development of a biocompatible coating of medical implant materials allowing the binding of biodegradable drug-delivery systems in a way that their reloading might be possible. These novel coatings, able to bind biodegradable nanoparticles, may serve in the long run as drug carriers to mediate local pharmacological activity. After biodegradation of the nanoparticles, the binding sites could be reloaded with fresh drug-delivering particles. As a suitable receptor system for the nanoparticles, antibodies are anchored. The design of the receptor is of great importance as any bio- or chemorecognitive interaction with other components circulating in the blood has to be avoided. Furthermore, the binding between receptor and the particles has to be strong enough to keep them tightly bound during their lifetime, but on the other hand allow reloading after final degradation of the particles. The nanoparticles suggested as a drug-delivery system for medical implants can be loaded with different pharmaceuticals such as antibiotics, growth factors, or immunosuppressives. This concept may enable the changing of medication, even after implantation of the medical device, if afforded by patients’ needs. PMID:24198488

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.

Biological consequences from interaction of nanosized titanium(iv) oxides with defined human blood components

NASA Astrophysics Data System (ADS)

Stella, Aaron

The utility of engineered nanomaterials is growing, particularly the titanium(iv) oxide (titanium dioxide, TiO2) nanoparticles. TiO 2 is very useful for brightening paints, and coloring foods. Nano-sized TiO2 is also useful for sunscreens, cosmetics, and can be utilized as a photocatalyst. However, the nanometer size of the TiO2 nanoparticle is a characteristic that may contribute oxidative stress to red blood cells (RBCs) in humans. This study utilized screening methods to evaluate different forms of TiO2 nanoparticles which differ by primary particle size, specific surface area, crystalline phase, and surface polarity. RBCs are rich in the intracellular antioxidant glutathione (GSH). HPLC analysis revealed that some TiO2 nanoparticles caused oxidation of GSH to glutathione disulfide (GSSG). Vitamin E is a major membrane-bound antioxidant. Vitamin E levels were then determined by HPLC in the RBC membrane after exposure to TiO2 nanoparticles. The HPLC results showed that each nanoparticle oxidized RBC glutathione and membrane vitamin E at different rates. When hemoglobin was mixed with each TiO2 nanoparticle, hemoglobin was adsorbed at varying rates to the surface of the nanoparticles. Similarly, the aminothiol homocysteine was also adsorbed at different rates by the TiO2 nanoparticles. Using light microscopy, some TiO2 nanoparticles caused the formation of RBC aggregates which significantly changed the RBC morphology. The aggregation data was quantified using a hemacytometer. The TiO2 nanoparticles also caused hemolysis of RBCs. Hemolysis is considered to be a toxic endpoint for RBCs. Changes in the nucleated lymphocyte gene expression of certain oxidative stress genes were also observed using real-time polymerase chain reaction (qPCR). The data indicates that RBCs can ultimately be hemolyzed by biological oxidative damage resulting from a combination of oxidative mechanisms. Additionally, the TiO2 nanoparticles demonstrated the ability to adsorb biomolecules to their surface which could be useful for nanomedicine purposes or biosensing applications. The changes in lymphocyte gene expression at different doses indicate that these TiO2 nanoparticles are capable of disrupting nuclear activity. The use of multiple screening methods provided an effective approach to evaluate nano-bio interactions. The use of a biologically-relevant matrix combined with specific detection methods yielded results which accurately predict biological adversity.

Fireball as the result of self-organization of an ensemble of diamagnetic electron-ion nanoparticles in molecular gas

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

Lopasov, V. P., E-mail: lopas@iao.ru

The conditions for dissipative self-organization of a fireball (FB) is a molecular gas by means of a regular correction of an elastic collision of water and nitrogen molecules by the field of a coherent bi-harmonic light wave (BLW) are presented. The BWL field is generated due to conversion of energy of a linear lightning discharge into light energy. A FB consists of two components: an ensemble of optically active diamagnetic electron-ion nanoparticles and a standing wave of elliptical polarization (SWEP). It is shown that the FB lifetime depends on the energies accumulated by nanoparticles and the SWEP field and onmore » the stability of self-oscillations of the energy between nanoparticles and SWEP.« less

Thermodynamics and Charging of Interstellar Iron Nanoparticles

NASA Astrophysics Data System (ADS)

Hensley, Brandon S.; Draine, B. T.

2017-01-01

Interstellar iron in the form of metallic iron nanoparticles may constitute a component of the interstellar dust. We compute the stability of iron nanoparticles to sublimation in the interstellar radiation field, finding that iron clusters can persist down to a radius of ≃4.5 Å, and perhaps smaller. We employ laboratory data on small iron clusters to compute the photoelectric yields as a function of grain size and the resulting grain charge distribution in various interstellar environments, finding that iron nanoparticles can acquire negative charges, particularly in regions with high gas temperatures and ionization fractions. If ≳10% of the interstellar iron is in the form of ultrasmall iron clusters, the photoelectric heating rate from dust may be increased by up to tens of percent relative to dust models with only carbonaceous and silicate grains.

Nanoparticle PEBBLE sensors in live cells and in vivo

PubMed Central

Smith, Ron

2009-01-01

Nanoparticle sensors have been developed for imaging and dynamic monitoring, in live cells and in vivo, of the molecular or ionic components, constructs, forces and dynamics, all in real time, during biological/chemical/physical processes. With their biocompatible small size and inert matrix, nanoparticle sensors have been successfully applied for non-invasive real-time measurements of analytes and fields in cells and rodents, with spatial, temporal, physical and chemical resolution. This review describes the diverse designs of nanoparticle sensors for ions and small molecules, physical fields and biological features, as well as the characterization, properties, and applications of these nanosensors to in vitro and in vivo measurements. Their floating as well as localization ability in biological media is captured by the acronym PEBBLE: photonic explorer for bioanalysis with biologically localized embedding. PMID:20098636

Using nuclear microscopy to characterize the interaction of textile-used silver nanoparticles with a biological wastewater treatment system

NASA Astrophysics Data System (ADS)

Bento, J. B.; Franca, R. D. G.; Pinheiro, T.; Alves, L. C.; Pinheiro, H. M.; Lourenço, N. D.

2017-08-01

The use of engineered nanoparticles in the textile industry has been rapidly increasing but their fate during biological wastewater treatment is largely unknown. The goal of the current study was to characterize the interaction of silver nanoparticles (AgNPs), used in the textile industry, with a biological wastewater treatment system based on aerobic granular sludge (AGS). The exposure tests were performed using a laboratory-scale sequencing batch reactor (SBR) system with AGS. The behavior and fate of textile AgNPs in the AGS system was studied with nuclear microscopy techniques. Elemental maps of AGS samples collected from the SBR showed that AgNPs typically clustered in agglomerates of small dimensions (<10 μm), which were preferentially associated with extracellular polymeric substances (EPS). This preliminary study highlights the potential application of nuclear microscopy for the characterization of the behavior and fate of AgNPs in AGS. The detailed compartmentalization of AgNPs in AGS components obtained with nuclear microscopy provides new and relevant information concerning AgNPs retention. This will be important in biotechnological terms to delineate strategies for AgNPs removal from textile wastewater.

Charge-transfer-based terbium MOF nanoparticles as fluorescent pH sensor for extreme acidity.

PubMed

Qi, Zewan; Chen, Yang

2017-01-15

Newly emerged metal organic frameworks (MOFs) have aroused the great interest in designing functional materials by means of its flexible structure and component. In this study, we used lanthanide Tb 3+ ions and small molecular ligands to design and assemble a kind of pH-sensitive MOF nanoparticle based on intramolecular-charge-transfer effect. This kind of made-to-order MOF nanoparticle for H + is highly specific and sensitive and could be used to fluorescently indicate pH value of strong acidic solution via preset mechanism through luminescence of Tb 3+ . The long luminescence lifetime of Tb 3+ allows eliminating concomitant non-specific fluorescence by time-revised fluorescence techniques, processing an advantage in sensing H + in biological media with strong autofluorescence. Our method showed a great potential of MOF structures in designing and constructing sensitive sensing materials for specific analytes directly via the assembly of functional ions/ligands. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of quantum coherence and interference in atoms near nanoparticles

NASA Astrophysics Data System (ADS)

Dhayal, Suman; Rostovtsev, Yuri V.

2016-04-01

Optical properties of ensembles of realistic quantum emitters coupled to plasmonic systems are studied by using adequate models that can take into account full atomic geometry. In particular, the coherent effects such as forming "dark states," optical pumping, coherent Raman scattering, and the stimulated Raman adiabatic passage (STIRAP) are revisited in the presence of metallic nanoparticles. It is shown that the dark states are still formed but they have more complicated structure, and the optical pumping and the STIRAP cannot be employed in the vicinity of plasmonic nanostructures. Also, there is a huge difference in the behavior of the local atomic polarization and the atomic polarization averaged over an ensemble of atoms homogeneously spread near nanoparticles. The average polarization is strictly related to the polarization induced by the external field, while the local polarization can be very different from the one induced by the external field. This is important for the excitation of single molecules, e.g., different components of scattering from single molecules can be used for their efficient detection.

Protein-like Nanoparticles Based on Orthogonal Self-Assembly of Chimeric Peptides.

PubMed

Jiang, Linhai; Xu, Dawei; Namitz, Kevin E; Cosgrove, Michael S; Lund, Reidar; Dong, He

2016-10-01

A novel two-component self-assembling chimeric peptide is designed where two orthogonal protein folding motifs are linked side by side with precisely defined position relative to one another. The self-assembly is driven by a combination of symmetry controlled molecular packing, intermolecular interactions, and geometric constraint to limit the assembly into compact dodecameric protein nanoparticles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An approach for environmental risk assessment of engineered nanomaterials using Analytical Hierarchy Process (AHP) and fuzzy inference rules.

PubMed

Topuz, Emel; van Gestel, Cornelis A M

2016-01-01

The usage of Engineered Nanoparticles (ENPs) in consumer products is relatively new and there is a need to conduct environmental risk assessment (ERA) to evaluate their impacts on the environment. However, alternative approaches are required for ERA of ENPs because of the huge gap in data and knowledge compared to conventional pollutants and their unique properties that make it difficult to apply existing approaches. This study aims to propose an ERA approach for ENPs by integrating Analytical Hierarchy Process (AHP) and fuzzy inference models which provide a systematic evaluation of risk factors and reducing uncertainty about the data and information, respectively. Risk is assumed to be the combination of occurrence likelihood, exposure potential and toxic effects in the environment. A hierarchy was established to evaluate the sub factors of these components. Evaluation was made with fuzzy numbers to reduce uncertainty and incorporate the expert judgements. Overall score of each component was combined with fuzzy inference rules by using expert judgements. Proposed approach reports the risk class and its membership degree such as Minor (0.7). Therefore, results are precise and helpful to determine the risk management strategies. Moreover, priority weights calculated by comparing the risk factors based on their importance for the risk enable users to understand which factor is effective on the risk. Proposed approach was applied for Ag (two nanoparticles with different coating) and TiO2 nanoparticles for different case studies. Results verified the proposed benefits of the approach. Copyright © 2016 Elsevier Ltd. All rights reserved.

Protein Corona Modulates Uptake and Toxicity of Nanoceria via Clathrin-Mediated Endocytosis.

PubMed

Mazzolini, Julie; Weber, Ralf J M; Chen, Hsueh-Shih; Khan, Abdullah; Guggenheim, Emily; Shaw, Robert K; Chipman, James K; Viant, Mark R; Rappoport, Joshua Z

2016-08-01

Particles present in diesel exhaust have been proposed as a significant contributor to the development of acute and chronic lung diseases, including respiratory infection and allergic asthma. Nanoceria (CeO2 nanoparticles) are used to increase fuel efficiency in internal combustion engines, are present in exhaust fumes, and could affect cells of the airway. Components from the environment such as biologically derived proteins, carbohydrates, and lipids can form a dynamic layer, commonly referred to as the "protein corona" which alters cellular nanoparticle interactions and internalization. Using confocal reflectance microscopy, we quantified nanoceria uptake by lung-derived cells in the presence and absence of a serum-derived protein corona. Employing mass spectrometry, we identified components of the protein corona, and demonstrated that the interaction between transferrin in the protein corona and the transferrin receptor is involved in mediating the cellular entry of nanoceria via clathrin-mediated endocytosis. Furthermore, under these conditions nanoceria does not affect cell growth, viability, or metabolism, even at high concentration. Alternatively, despite the antioxidant capacity of nanoceria, in serum-free conditions these nanoparticles induce plasma membrane disruption and cause changes in cellular metabolism. Thus, our results identify a specific receptor-mediated mechanism for nanoceria entry, and provide significant insight into the potential for nanoparticle-dependent toxicity. © 2016 Marine Biological Laboratory.

In situ ultra-small-angle X-ray scattering study under uniaxial stretching of colloidal crystals prepared by silica nanoparticles bearing hydrogen-bonding polymer grafts

DOE PAGES

Ishige, Ryohei; Williams, Gregory A.; Higaki, Yuji; ...

2016-04-19

A molded film of single-component polymer-grafted nanoparticles (SPNP), consisting of a spherical silica core and densely grafted polymer chains bearing hydrogen-bonding side groups capable of physical crosslinking, was investigated byin situultra-small-angle X-ray scattering (USAXS) measurement during a uniaxial stretching process. Static USAXS revealed that the molded SPNP formed a highly oriented twinned face-centered cubic (f.c.c.) lattice structure with the [11-1] plane aligned nearly parallel to the film surface in the initial state. Structural analysis ofin situUSAXS using a model of uniaxial deformation induced by rearrangement of the nanoparticles revealed that the f.c.c. lattice was distorted in the stretching direction inmore » proportion to the macroscopic strain until the strain reached 35%, and subsequently changed into other f.c.c. lattices with different orientations. The lattice distortion and structural transition behavior corresponded well to the elastic and plastic deformation regimes, respectively, observed in the stress–strain curve. The attractive interaction of the hydrogen bond is considered to form only at the top surface of the shell and then plays an effective role in cross-linking between nanoparticles. The rearrangement mechanism of the nanoparticles is well accounted for by a strong repulsive interaction between the densely grafted polymer shells of neighboring particles.« less

Production of a Novel Fucoidanase for the Green Synthesis of Gold Nanoparticles by Streptomyces sp. and Its Cytotoxic Effect on HeLa Cells

PubMed Central

Manivasagan, Panchanathan; Oh, Junghwan

2015-01-01

Marine actinobacteria-produced fucoidanases have received considerable attention as one of the major research topics in recent years, particularly for the medical exploitation of fucoidans and their degradation products. The present study describes the optimization and production of a novel fucoidanase for the green synthesis of gold nanoparticles and its biological applications. The production of fucoidanase was optimized using Streptomyces sp. The medium components were selected in accordance with the Plackett-Burman design and were further optimized via response surface methodology. The fucoidanase was statistically optimized with the most significant factors, namely wheat bran 3.3441 g/L, kelp powder 0.7041 g/L, and NaCl 0.8807 g/L, respectively. The biosynthesized gold nanoparticles were determined by UV-vis spectroscopy and were further characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis, and high-resolution transmission electron microscopy. Furthermore, the biosynthesized gold nanoparticles exhibited a dose-dependent cytotoxicity against HeLa cells and the inhibitory concentration (IC50) was found to be 350 µg/mL at 24 h and 250 µg/mL at 48 h. Therefore, the production of novel fucoidanase for the green synthesis of gold nanoparticles has comparatively rapid, less expensive and wide application to anticancer therapy in modern medicine. PMID:26569267

Production of a Novel Fucoidanase for the Green Synthesis of Gold Nanoparticles by Streptomyces sp. and Its Cytotoxic Effect on HeLa Cells.

PubMed

Manivasagan, Panchanathan; Oh, Junghwan

2015-11-12

Marine actinobacteria-produced fucoidanases have received considerable attention as one of the major research topics in recent years, particularly for the medical exploitation of fucoidans and their degradation products. The present study describes the optimization and production of a novel fucoidanase for the green synthesis of gold nanoparticles and its biological applications. The production of fucoidanase was optimized using Streptomyces sp. The medium components were selected in accordance with the Plackett-Burman design and were further optimized via response surface methodology. The fucoidanase was statistically optimized with the most significant factors, namely wheat bran 3.3441 g/L, kelp powder 0.7041 g/L, and NaCl 0.8807 g/L, respectively. The biosynthesized gold nanoparticles were determined by UV-vis spectroscopy and were further characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis, and high-resolution transmission electron microscopy. Furthermore, the biosynthesized gold nanoparticles exhibited a dose-dependent cytotoxicity against HeLa cells and the inhibitory concentration (IC50) was found to be 350 µg/mL at 24 h and 250 µg/mL at 48 h. Therefore, the production of novel fucoidanase for the green synthesis of gold nanoparticles has comparatively rapid, less expensive and wide application to anticancer therapy in modern medicine.

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization.

PubMed

Gopi, D; Kanimozhi, K; Bhuvaneshwari, N; Indira, J; Kavitha, L

2014-01-24

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy ((1)H NMR) and carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization

NASA Astrophysics Data System (ADS)

Gopi, D.; Kanimozhi, K.; Bhuvaneshwari, N.; Indira, J.; Kavitha, L.

2014-01-01

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy (1H NMR) and carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications.

Biogenic Nanoparticles from Schwanniomyces occidentalis NCIM 3459: Mechanistic Aspects and Catalytic Applications.

PubMed

Mohite, Pallavi; Apte, Mugdha; Kumar, Ameeta Ravi; Zinjarde, Smita

2016-06-01

When cells of Schwanniomyces occidentalis NCIM 3459 were incubated with 1 mM tetrachloroauric acid (HAuCl4) or silver nitrate (AgNO3), cell-associated nanoparticles were obtained. Their presence was confirmed by scanning electron microscope observations. The cell-free supernatant (CFS) of the yeast mediated the synthesis of gold nanoparticles. On account of the difficulties associated with the use of cell-bound nanoparticles, further work was restricted to extracellular nanoparticles. It was hypothesized that the CFS contained thermostable biomolecule(s) that mediated metal reduction reactions. Extraction of the CFS with chloroform/methanol (2:1) and subsequent separation by preparative thin layer chromatography led to the activity-guided purification of a glycolipid. The glycolipid was hydrolyzed and the glycone (glucose) and aglycone components (palmitic acid and oleic acid) were identified by gas chromatography-mass spectrometry. The purified glycolipid mediated the synthesis of gold and silver nanoparticles that were characterized by using an X-ray diffractometer and transmission electron microscope (TEM). The extracellular nanoparticles displayed catalytic activities and reduced 4-nitroaniline to benzene-1,4-diamine. This paper thus highlights nanoparticle synthesis by a hitherto unreported yeast culture, identifies the biomolecules involved in the process, and describes a potential application of the nanostructures.

A new, simple, green, and one-pot four-component synthesis of bare and poly(α,γ, L-glutamic acid)-capped silver nanoparticles

PubMed Central

Savanović, Igor; Uskoković, Vuk; Škapin, Srečo D.; Bračko, Ines; Jovanović, Uroš; Uskoković, Dragan

2013-01-01

A simple and green chemical method has been developed to synthesize stable bare and capped silver nanoparticles based on the reduction of silver ions by glucose and capping by poly(α,γ,L-glutamic acid) (PGA). The use of ammonia during synthesis was avoided. PGA has had a dual role in the synthesis and was used as a capping agent to make the silver nanoparticle more biocompatible and to protect the nanoparticles from agglomerating in the liquid medium. The synthesized PGA-capped silver nanoparticles in the size range 5–45 nm were stable over long periods of time, without signs of precipitation. Morphological examination has shown that the silver nanoparticles had a nearly spherical, multiply twinned structure. The effects of the reaction temperature and the reaction time during the synthesis were investigated too. The biocompatibility of the PGA-capped silver nano-particles is discussed in terms of in vitro toxicity with human intestinal Caco-2 cells. The samples were characterized by UV–Visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurements. PMID:24062597

The role of interfacial metal silicates on the magnetism in FeCo/SiO 2 and Fe 49% Co 49% V 2% /SiO 2 core/shell nanoparticles

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

Desautels, R. D.; Freeland, J. W.; Rowe, M. P.

2015-05-07

We have investigated the role of spontaneously formed interfacial metal silicates on the magnetism of FeCo/SiO2 and Fe49%Co49%V2%/SiO2 core/shell nanoparticles. Element specific x-ray absorption and photoelectron spectroscopy experiments have identified the characteristic spectral features of metallic iron and cobalt from within the nanoparticle core. In addition, metal silicates of iron, cobalt, and vanadium were found to have formed spontaneously at the interface between the nanoparticle core and silica shell. X-ray magnetic circular dichroism experiments indicated that the elemental magnetism was a result of metallic iron and cobalt with small components from the iron, cobalt, and vanadium silicates. Magnetometry experiments havemore » shown that there was no exchange bias loop shift in the FeCo nanoparticles; however, exchange bias from antiferromagnetic vanadium oxide was measured in the V-doped nanoparticles. These results showed clearly that the interfacial metal silicates played a significant role in the magnetism of these core/shell nanoparticles, and that the vanadium percolated from the FeCo-cores into the SiO2-based interfacial shell.« less

Effects of magnetic cobalt ferrite nanoparticles on biological and artificial lipid membranes

PubMed Central

Drašler, Barbara; Drobne, Damjana; Novak, Sara; Valant, Janez; Boljte, Sabina; Otrin, Lado; Rappolt, Michael; Sartori, Barbara; Iglič, Aleš; Kralj-Iglič, Veronika; Šuštar, Vid; Makovec, Darko; Gyergyek, Sašo; Hočevar, Matej; Godec, Matjaž; Zupanc, Jernej

2014-01-01

Background The purpose of this work is to provide experimental evidence on the interactions of suspended nanoparticles with artificial or biological membranes and to assess the possibility of suspended nanoparticles interacting with the lipid component of biological membranes. Methods 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid vesicles and human red blood cells were incubated in suspensions of magnetic bare cobalt ferrite (CoFe2O4) or citric acid (CA)-adsorbed CoFe2O4 nanoparticles dispersed in phosphate-buffered saline and glucose solution. The stability of POPC giant unilamellar vesicles after incubation in the tested nanoparticle suspensions was assessed by phase-contrast light microscopy and analyzed with computer-aided imaging. Structural changes in the POPC multilamellar vesicles were assessed by small angle X-ray scattering, and the shape transformation of red blood cells after incubation in tested suspensions of nanoparticles was observed using scanning electron microscopy and sedimentation, agglutination, and hemolysis assays. Results Artificial lipid membranes were disturbed more by CA-adsorbed CoFe2O4 nanoparticle suspensions than by bare CoFe2O4 nanoparticle suspensions. CA-adsorbed CoFe2O4-CA nanoparticles caused more significant shape transformation in red blood cells than bare CoFe2O4 nanoparticles. Conclusion Consistent with their smaller sized agglomerates, CA-adsorbed CoFe2O4 nanoparticles demonstrate more pronounced effects on artificial and biological membranes. Larger agglomerates of nanoparticles were confirmed to be reactive against lipid membranes and thus not acceptable for use with red blood cells. This finding is significant with respect to the efficient and safe application of nanoparticles as medicinal agents. PMID:24741305

Ultrasound-mediated delivery and distribution of polymeric nanoparticles in the normal brain parenchyma of a metastatic brain tumour model

PubMed Central

Baghirov, Habib; Snipstad, Sofie; Sulheim, Einar; Berg, Sigrid; Hansen, Rune; Thorsen, Frits; Mørch, Yrr; Åslund, Andreas K. O.

2018-01-01

The treatment of brain diseases is hindered by the blood-brain barrier (BBB) preventing most drugs from entering the brain. Focused ultrasound (FUS) with microbubbles can open the BBB safely and reversibly. Systemic drug injection might induce toxicity, but encapsulation into nanoparticles reduces accumulation in normal tissue. Here we used a novel platform based on poly(2-ethyl-butyl cyanoacrylate) nanoparticle-stabilized microbubbles to permeabilize the BBB in a melanoma brain metastasis model. With a dual-frequency ultrasound transducer generating FUS at 1.1 MHz and 7.8 MHz, we opened the BBB using nanoparticle-microbubbles and low-frequency FUS, and applied high-frequency FUS to generate acoustic radiation force and push nanoparticles through the extracellular matrix. Using confocal microscopy and image analysis, we quantified nanoparticle extravasation and distribution in the brain parenchyma. We also evaluated haemorrhage, as well as the expression of P-glycoprotein, a key BBB component. FUS and microbubbles distributed nanoparticles in the brain parenchyma, and the distribution depended on the extent of BBB opening. The results from acoustic radiation force were not conclusive, but in a few animals some effect could be detected. P-glycoprotein was not significantly altered immediately after sonication. In summary, FUS with our nanoparticle-stabilized microbubbles can achieve accumulation and displacement of nanoparticles in the brain parenchyma. PMID:29338016

Alkaline Capacitors Based on Nitride Nanoparticles

NASA Technical Reports Server (NTRS)

Aldissi, Matt

2003-01-01

High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

Role of fin material and nanofluid in performance enhancement of automobile radiator

NASA Astrophysics Data System (ADS)

Jadar, Raju; Shashishekar, K. S.; Channa Keshava Naik, N.

2018-04-01

An effective cooling system can avoid engine and its components from overheating and helps in achieving optimum engine performance. This work deals with the fabrication and performance evaluation of an automobile radiator with i) Aluminum fins and ii) Al-MWCNT fins using 0.1 w/v% f-MWCNT nanofluid. F-MWCNT nanoparticles in the base fluid improves the rate of heat transfer in an automobile radiator integrated with Al-MWCNT fins. The enhancement of heat transfer mainly depends on the quantity of F-MWCNT nanoparticles added to the host fluid. During the study it was found that at a low weight by volume concentration of nanofluid the heat transfer enhancement of 8% was achieved using Al-MWCNT fins compared to base fluid.

Dynamic electrical characteristics of low-power ring oscillators constructed with inorganic nanoparticles on flexible plastics.

PubMed

Yun, Junggwon; Cho, Kyoungah; Kim, Sangsig

2012-11-01

In this study, we demonstrate for the first time the low-power and stable performance of a ring oscillator constructed on a flexible plastic with solution-processable inorganic nanoparticles (NPs). Our flexible ring oscillator is composed of three inverters based on n- and p-type inorganic NP thin-film transistors. Each of the component inverters exhibits a gain of ∼80 at a voltage of 5 V. For the ring oscillator, the sine waves are generated with a frequency of up to 12 kHz. The waveforms are undistorted under strained conditions and maintained even after 5000 bending cycles. The frequency and waveform of the output waves obtained from our flexible ring oscillator are analyzed and discussed in detail.

Preparation of metallic nanoparticles by irradiation in starch aqueous solution

NASA Astrophysics Data System (ADS)

NemÅ£anu, Monica R.; Braşoveanu, Mirela; Iacob, Nicuşor

2014-11-01

Colloidal silver nanoparticles (AgNPs) were synthesized in a single step by electron beam irradiation reduction of silver ions in aqueous solution containing starch. The nanoparticles were characterized by spectrophotocolorimetry and compared with those obtained by chemical (thermal) reduction method. The results showed that the smaller sizes of AgNPs were prepared with higher yields as the irradiation dose increased. The broadening of particle size distribution occurred by increasing of irradiation dose and dose rate. Chromatic parameters such as b* (yellow-blue coordinate), C* (chroma) and ΔEab (total color difference) could characterize the nanoparticles with respect of their concentration. Hue angle ho was correlated to the particle size distribution. Experimental data of the irradiated samples were also subjected to factor analysis using principal component extraction and varimax rotation in order to reveal the relation between dependent variables and independent variables and to reduce their number. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those produced by chemical reduction method. Therefore, the electron beam irradiation is effective for preparation of silver nanoparticles using starch aqueous solution as dispersion medium.

Uptake of bright fluorophore core-silica shell nanoparticles by biological systems

PubMed Central

Zane, Andrew; McCracken, Christie; Knight, Deborah A; Young, Tanya; Lutton, Anthony D; Olesik, John W; Waldman, W James; Dutta, Prabir K

2015-01-01

Nanoparticles are used in a variety of consumer applications. Silica nanoparticles in particular are common, including as a component of foods. There are concerns that ingested nano-silica particles can cross the intestinal epithelium, enter the circulation, and accumulate in tissues and organs. Thus, tracking these particles is of interest, and fluorescence spectroscopic methods are well-suited for this purpose. However, nanosilica is not fluorescent. In this article, we focus on core-silica shell nanoparticles, using fluorescent Rhodamine 6G, Rhodamine 800, or CdSe/CdS/ZnS quantum dots as the core. These stable fluorophore/silica nanoparticles had surface characteristics similar to those of commercial silica particles. Thus, they were used as model particles to examine internalization by cultured cells, including an epithelial cell line relevant to the gastrointestinal tract. Finally, these particles were administered to mice by gavage, and their presence in various organs, including stomach, small intestine, cecum, colon, kidney, lung, brain, and spleen, was examined. By combining confocal fluorescence microscopy with inductively coupled plasma mass spectrometry, the presence of nanoparticles, rather than their dissolved form, was established in liver tissues. PMID:25759579

In vitro biological validation and cytocompatibility evaluation of hydrogel iron-oxide nanoparticles

NASA Astrophysics Data System (ADS)

Catalano, Enrico

2017-08-01

Superparamagnetic iron oxide nanoparticles (MNPs) have recently been investigated for their excellent biocompatibility as well as multi-purpose biomedical potential with promising results, owing to their ability to be targeted and heated by magnetic fields. In this study, novel hydrogel, chitosan Fe3O4 magnetic nanoparticles were synthesized for possible use for induced magnetic hyperthermia, and targeted drug delivery. The coating of iron oxide nanoparticles plays a key-role to efficiently improve internalization of nanoparticles in many cell types. Targeting is also highly desirable for these applications. In this regard hydrophilic coating like chitosan was used to improve drug release. Uncoated (Fe3O4)and chitosan-coated iron oxide nanoparticles (CS-Fe3O4) were synthesized and characterized from the biological point of view. The aim of this study was to provide an in vitro evaluation of the cytocompatibility of Fe3O4 and CS-Fe3O4 MNPs by using different in vitro evaluation tests. In this context, the cytocompatibility and cytotoxic effects of uncoated and hydrogel chemically-engineered chitosan-coated iron oxide NPs were investigated according to the ISO standard 10993-5:2009. Fe3O4 and CS-Fe3O4 NPs were tested on human mammary epithelial cells (MCF-10A) by using direct and not direct contact cytotoxicity evaluation tests, by evaluating influence of the iron particles on the cytoskeleton with phalloidin/DAPI staining and in vitro cellular iron uptake with Perl's Prussian blue staining. The results indicate that uncoated and chitosan-coated iron oxide nanoparticles are cytocompatible, without negative influence on the cytoskeleton or higher accumulation of iron in the cytoplasm. Therefore, it is encouraging that our data suggest uncoated and chitosan-coated iron oxide nanoparticles have satisfactory proliferative and viability effects on MCF-10A cells. In conclusion data suggest that both MNP types may be differently aimed in biomedical application in relation to the dose, acting as biocompatible materials, as component of scaffolds, or as a device for theranostics.

Media milling process optimization for manufacture of drug nanoparticles using design of experiments (DOE).

PubMed

Nekkanti, Vijaykumar; Marwah, Ashwani; Pillai, Raviraj

2015-01-01

Design of experiments (DOE), a component of Quality by Design (QbD), is systematic and simultaneous evaluation of process variables to develop a product with predetermined quality attributes. This article presents a case study to understand the effects of process variables in a bead milling process used for manufacture of drug nanoparticles. Experiments were designed and results were computed according to a 3-factor, 3-level face-centered central composite design (CCD). The factors investigated were motor speed, pump speed and bead volume. Responses analyzed for evaluating these effects and interactions were milling time, particle size and process yield. Process validation batches were executed using the optimum process conditions obtained from software Design-Expert® to evaluate both the repeatability and reproducibility of bead milling technique. Milling time was optimized to <5 h to obtain the desired particle size (d90 < 400 nm). The desirability function used to optimize the response variables and observed responses were in agreement with experimental values. These results demonstrated the reliability of selected model for manufacture of drug nanoparticles with predictable quality attributes. The optimization of bead milling process variables by applying DOE resulted in considerable decrease in milling time to achieve the desired particle size. The study indicates the applicability of DOE approach to optimize critical process parameters in the manufacture of drug nanoparticles.

Intracellular trafficking of silicon particles and logic-embedded vectors

NASA Astrophysics Data System (ADS)

Ferrati, Silvia; Mack, Aaron; Chiappini, Ciro; Liu, Xuewu; Bean, Andrew J.; Ferrari, Mauro; Serda, Rita E.

2010-08-01

Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon particles to be optimized for specific applications such as vascular targeting and avoidance of biological barriers commonly found between the site of drug injection and the final destination. In this study, the intracellular trafficking of unloaded carrier silicon particles and carrier particles loaded with secondary iron oxide nanoparticles was investigated. Following cellular uptake, membrane-encapsulated silicon particles migrated to the perinuclear region of the cell by a microtubule-driven mechanism. Surface charge, shape (spherical and hemispherical) and size (1.6 and 3.2 μm) of the particle did not alter the rate of migration. Maturation of the phagosome was associated with an increase in acidity and acquisition of markers of late endosomes and lysosomes. Cellular uptake of iron oxide nanoparticle-loaded silicon particles resulted in sorting of the particles and trafficking to unique destinations. The silicon carriers remained localized in phagosomes, while the second stage iron oxide nanoparticles were sorted into multi-vesicular bodies that dissociated from the phagosome into novel membrane-bound compartments. Release of iron from the cells may represent exocytosis of iron oxide nanoparticle-loaded vesicles. These results reinforce the concept of multi-functional nanocarriers, in which different particles are able to perform specific tasks, in order to deliver single- or multi-component payloads to specific sub-cellular compartments.Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon particles to be optimized for specific applications such as vascular targeting and avoidance of biological barriers commonly found between the site of drug injection and the final destination. In this study, the intracellular trafficking of unloaded carrier silicon particles and carrier particles loaded with secondary iron oxide nanoparticles was investigated. Following cellular uptake, membrane-encapsulated silicon particles migrated to the perinuclear region of the cell by a microtubule-driven mechanism. Surface charge, shape (spherical and hemispherical) and size (1.6 and 3.2 μm) of the particle did not alter the rate of migration. Maturation of the phagosome was associated with an increase in acidity and acquisition of markers of late endosomes and lysosomes. Cellular uptake of iron oxide nanoparticle-loaded silicon particles resulted in sorting of the particles and trafficking to unique destinations. The silicon carriers remained localized in phagosomes, while the second stage iron oxide nanoparticles were sorted into multi-vesicular bodies that dissociated from the phagosome into novel membrane-bound compartments. Release of iron from the cells may represent exocytosis of iron oxide nanoparticle-loaded vesicles. These results reinforce the concept of multi-functional nanocarriers, in which different particles are able to perform specific tasks, in order to deliver single- or multi-component payloads to specific sub-cellular compartments. Electronic supplementary information (ESI) available: Confocal microscopy image showing internalized negative particles, and movie of the intracellular migration of silicon particles. See DOI: 10.1039/c0nr00227e

Application of Fiber Optic ATR-FTIR Methods for In Situ Characterization of Protein Delivery Systems in Real Time

PubMed Central

McFearin, Cathryn L.; Sankaranarayanan, Jagadis; Almutairi, Adah

2011-01-01

Real Time Characterization of Protein Delivery Systems A fiber optic coupled ATR-FTIR spectroscopy technique was applied to the study of two different therapeutic delivery systems, acid degradable hydrogels and nanoparticles. Real time exponential release of a model protein, human serum albumin (HSA), was observed from two different polymeric hydrogels formulated with a pH sensitive crosslinker. Spectroscopic examination of nanoparticles formulated with an acid degradable polymer shell and encapsulated HSA exhibited vibrational signatures characteristic of both particle and payload when exposed to lowered pH conditions demonstrating the ability of this methodology to simultaneously measure phenomena arising from a system with a mixture of components. In addition, thorough characterization of these pH sensitive delivery vehicles without encapsulated protein was also accomplished in order to separate the effects of the payload during degradation. By providing in situ, real time detection in combination with the ability to specifically identify different components in a mixture without involved sample preparation and minimal sample disturbance, the versatility and suitability of this type of experiment for research in the pharmaceutical field is demonstrated. PMID:21476582

Inbuilt Potential of YEM Medium and Its Constituents to Generate Ag/Ag2O Nanoparticles

PubMed Central

Yamal, G.; Sharmila, P.; Rao, K. S.; Pardha-Saradhi, P.

2013-01-01

We discovered that Yeast Extract Mannitol (YEM) medium possessed immense potential to generate silver nanoparticles from AgNO3 upon autoclaving, which was evident from (i) alteration in color of the medium; (ii) peak at ∼410 nm in UV-Vis spectrum due to surface plasmon resonance specific to silver nanoparticles; and (iii) TEM investigations. TEM coupled with EDX confirmed that distinct nanoparticles were composed of silver. Yeast extract and mannitol were key components of YEM medium responsible for the formation of nanoparticles. PXRD analysis indicated crystalline geometry and Ag/Ag2O phases in nanoparticles generated with YEM medium, yeast extract and mannitol. Our investigations also revealed that both mannitol and yeast extract possessed potential to convert ∼80% of silver ions in 0.5 mM AgNO3 to nanoparticles, on autoclaving for 30 min at 121°C under a pressure of 1.06 kg/cm2. Addition of filter sterilized AgNO3 under ambient conditions to pre-autoclaved YEM medium and yeast extract brought about color change due to the formation of silver nanoparticles, but required prolonged duration. In general, even after 72 h intensity of color was significantly less than that recorded following autoclaving. Silver nanoparticles formed at room temperature were more heterogeneous compared to that obtained upon autoclaving. In summary, our findings demonstrated that (i) YEM medium and its constituents promote synthesis of silver nanoparticles; and (ii) autoclaving enhances rapid synthesis of silver nanoparticles by YEM medium, yeast extract and mannitol. PMID:23626722

An improved, non-functionalized route to plasmonic nanoparticle based cellular probing through osmolyte mediation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Siddhanta, Soumik; Barman, Ishan

2017-02-01

Engineering nanostructured probes for ultra-sensitive detection of specific molecular species, our research seeks to capture the complex changes in cells and tissues that can predict disease progression in an individual. While such nanoparticle-based platforms are rapidly gaining a foothold in cancer diagnostics, one of the most concerning factors is the vulnerability of cells to the interaction with functional nanoparticles thereby raising the specter of systemic toxicity. The nanoparticles end up damaging the cells and disrupting cellular functions thereby impeding their imaging aim. Furthermore, PEGylation, and similar routes, force a tradeoff between desired nanoparticle properties (recognition, uptake, and reduced toxicity) and sensitivity of plasmon-enhanced spectroscopic sensing methods, such as surface-enhanced Raman spectroscopy (SERS) where the proximal presence of noble metal NP and the organic molecule of interest is key. In this work, we report a trehalose-mediated, non-surface functionalized route for cell-nanoparticle interactions that maintains cell viability while allowing selective interaction of the nanoparticle with the cell surface receptors and subsequent internalization. Through careful electron microscopy of nanoparticle-prostate cancer cells interactions, we elucidated that there exists a dynamic equilibrium between "free" cytosolic diffusion of the nanoparticles and endocytosis through vesicle formation - and trehalose tilts the scale in favor of the latter to mask the toxic effects of the nanoparticles. The precise molecular interpretation of this behavior was further probed through SERS, which directly points towards the protein stabilization properties of trehalose mediation during interaction of the nanoparticles with the plasma membrane components.

Integrated Approach of Agri-nanotechnology: Challenges and Future Trends

PubMed Central

Mishra, Sandhya; Keswani, Chetan; Abhilash, P. C.; Fraceto, Leonardo F.; Singh, Harikesh Bahadur

2017-01-01

Nanotechnology representing a new frontier in modern agriculture is anticipated to become a major thrust in near future by offering potential applications. This integrating approach, i.e., agri-nanotechnology has great potential to cope with global challenges of food production/security, sustainability and climate change. However, despite the potential benefits of nanotechnology in agriculture so far, their relevance has not reached up to the field conditions. The elevating concerns about fate, transport, bioavailability, nanoparticles toxicity and inappropriateness of regulatory framework limit the complete acceptance and inclination to adopt nanotechnologies in agricultural sector. Moreover, the current research trends lack realistic approach that fail to attain comprehensive knowledge of risk assessment factors and further toxicity of nanoparticles toward agroecosystem components viz. plant, soil, soil microbiomes after their release into the environment. Hence in the present review we attempt to suggest certain key points to be addressed in the current and future agri-nanotechnology researches on the basis of recognized knowledge gaps with strong recommendation of incorporating biosynthesized nanoparticles to carry out analogous functions. In this perspective, the major points are as follows: (i) Mitigating risk assessment factors (responsible for fate, transport, behavior, bioavailability and toxicity) for alleviating the subsequent toxicity of nanoparticles. (ii) Optimizing permissible level of nanoparticles dose within the safety limits by performing dose dependent studies. (iii) Adopting realistic approach by designing the experiments in natural habitat and avoiding in vitro assays for accurate interpretation. (iv) Most importantly, translating environmental friendly and non-toxic biosynthesized nanoparticles from laboratory to field conditions for agricultural benefits. PMID:28421100

Hierarchically assembled theranostic nanostructures for siRNA delivery and imaging applications.

PubMed

Shrestha, Ritu; Elsabahy, Mahmoud; Luehmann, Hannah; Samarajeewa, Sandani; Florez-Malaver, Stephanie; Lee, Nam S; Welch, Michael J; Liu, Yongjian; Wooley, Karen L

2012-10-24

Dual functional hierarchically assembled nanostructures, with two unique functions of carrying therapeutic cargo electrostatically and maintaining radiolabeled imaging agents covalently within separate component building blocks, have been developed via the supramolecular assembly of several spherical cationic shell cross-linked nanoparticles clustered around a central anionic shell cross-linked cylinder. The shells of the cationic nanoparticles and the hydrophobic core domain of the anionic central cylindrical nanostructure of the assemblies were utilized to complex negatively charged nucleic acids (siRNA) and to undergo radiolabeling, respectively, for potential theranostic applications. The assemblies exhibited exceptional cell transfection and radiolabeling efficiencies, providing an overall advantage over the individual components, which could each facilitate only one or the other of the functions.

Magnetic dynamic properties of electron-doped La(0.23)Ca(0.77)MnO3 nanoparticles.

PubMed

Dolgin, B; Puzniak, R; Mogilyansky, D; Wisniewski, A; Markovich, V; Jung, G

2013-02-20

Magnetic properties of basically antiferromagnetic La(0.23)Ca(0.77)MnO(3) particles with average sizes of 12 and 60 nm have been investigated in a wide range of magnetic fields and temperature. Particular attention has been paid to magnetization dynamics through measurements of the temperature dependence of ac-susceptibility at various frequencies, the temperature and field dependence of thermoremanent and isothermoremanent magnetization originating from nanoparticles shells, and the time decay of the remanent magnetization. Experimental results and their analysis reveal the major role in magnetic behaviour of investigated antiferromagnetic nanoparticles played by the glassy component, associated mainly with the formation of the collective state formed by ferromagnetic clusters in frustrated coordination at the surfaces of interacting antiferromagnetic nanoparticles. Magnetic behaviour of nanoparticles has been ascribed to a core-shell scenario. Magnetic transitions have been found to play an important role in determining the dynamic properties of the phase separated state of coexisting different magnetic phases.

Dynamics of lipid saccharide nanoparticles by quasielastic neutron scattering

NASA Astrophysics Data System (ADS)

Di Bari, M. T.; Gerelli, Y.; Sonvico, F.; Deriu, A.; Cavatorta, F.; Albanese, G.; Colombo, P.; Fernandez-Alonso, F.

2008-04-01

Nano- and microparticles composed of saccharide and lipid systems are extensively investigated for applications as highly biocompatible drug carriers. A detailed understanding of particle-solvent interactions is of key importance in order to tailor their characteristics for delivering drugs with specific chemical properties. Here we report results of a quasielastic neutron scattering (QENS) investigation on lecithin/chitosan nanoparticles prepared by autoassembling the two components in an aqueous solution. The measurements were performed at room temperature on lyophilized and H 2O hydrated nanoparticles ( h = 0.47 w H 2O/w hydrated sample). In the latter, hydration water is mostly enclosed inside the nanoparticles; its dynamics is similar to that of bulk water but with a significant decrease in diffusivity. The scattering from the nanoparticles can be described by a simple model of confined diffusion. In the lyophilized state only hydrogens belonging to the polar heads are seen as mobile within the experimental time-window. In the hydrated sample the diffusive dynamics involves also a significant part of the hydrogens in the lipid tails.

Platinum-coated non-noble metal-noble metal core-shell electrocatalysts

DOEpatents

Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir

2015-04-14

Core-shell particles encapsulated by a thin film of a catalytically active metal are described. The particles are preferably nanoparticles comprising a non-noble core with a noble metal shell which preferably do not include Pt. The non-noble metal-noble metal core-shell nanoparticles are encapsulated by a catalytically active metal which is preferably Pt. The core-shell nanoparticles are preferably formed by prolonged elevated-temperature annealing of nanoparticle alloys in an inert environment. This causes the noble metal component to surface segregate and form an atomically thin shell. The Pt overlayer is formed by a process involving the underpotential deposition of a monolayer of a non-noble metal followed by immersion in a solution comprising a Pt salt. A thin Pt layer forms via the galvanic displacement of non-noble surface atoms by more noble Pt atoms in the salt. The overall process is a robust and cost-efficient method for forming Pt-coated non-noble metal-noble metal core-shell nanoparticles.

THERMODYNAMICS AND CHARGING OF INTERSTELLAR IRON NANOPARTICLES

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

Hensley, Brandon S.; Draine, B. T., E-mail: brandon.s.hensley@jpl.nasa.gov

Interstellar iron in the form of metallic iron nanoparticles may constitute a component of the interstellar dust. We compute the stability of iron nanoparticles to sublimation in the interstellar radiation field, finding that iron clusters can persist down to a radius of ≃4.5 Å, and perhaps smaller. We employ laboratory data on small iron clusters to compute the photoelectric yields as a function of grain size and the resulting grain charge distribution in various interstellar environments, finding that iron nanoparticles can acquire negative charges, particularly in regions with high gas temperatures and ionization fractions. If ≳10% of the interstellar ironmore » is in the form of ultrasmall iron clusters, the photoelectric heating rate from dust may be increased by up to tens of percent relative to dust models with only carbonaceous and silicate grains.« less

Electromagnetic energy transport in nanoparticle chains via dark plasmon modes.

PubMed

Solis, David; Willingham, Britain; Nauert, Scott L; Slaughter, Liane S; Olson, Jana; Swanglap, Pattanawit; Paul, Aniruddha; Chang, Wei-Shun; Link, Stephan

2012-03-14

Using light to exchange information offers large bandwidths and high speeds, but the miniaturization of optical components is limited by diffraction. Converting light into electron waves in metals allows one to overcome this problem. However, metals are lossy at optical frequencies and large-area fabrication of nanometer-sized structures by conventional top-down methods can be cost-prohibitive. We show electromagnetic energy transport with gold nanoparticles that were assembled into close-packed linear chains. The small interparticle distances enabled strong electromagnetic coupling causing the formation of low-loss subradiant plasmons, which facilitated energy propagation over many micrometers. Electrodynamic calculations confirmed the dark nature of the propagating mode and showed that disorder in the nanoparticle arrangement enhances energy transport, demonstrating the viability of using bottom-up nanoparticle assemblies for ultracompact opto-electronic devices. © 2012 American Chemical Society

Coherent diffraction imaging analysis of shape-controlled nanoparticles with focused hard X-ray free-electron laser pulses.

PubMed

Takahashi, Yukio; Suzuki, Akihiro; Zettsu, Nobuyuki; Oroguchi, Tomotaka; Takayama, Yuki; Sekiguchi, Yuki; Kobayashi, Amane; Yamamoto, Masaki; Nakasako, Masayoshi

2013-01-01

We report the first demonstration of the coherent diffraction imaging analysis of nanoparticles using focused hard X-ray free-electron laser pulses, allowing us to analyze the size distribution of particles as well as the electron density projection of individual particles. We measured 1000 single-shot coherent X-ray diffraction patterns of shape-controlled Ag nanocubes and Au/Ag nanoboxes and estimated the edge length from the speckle size of the coherent diffraction patterns. We then reconstructed the two-dimensional electron density projection with sub-10 nm resolution from selected coherent diffraction patterns. This method enables the simultaneous analysis of the size distribution of synthesized nanoparticles and the structures of particles at nanoscale resolution to address correlations between individual structures of components and the statistical properties in heterogeneous systems such as nanoparticles and cells.

Plasmonic Metallurgy Enabled by DNA

DOE PAGES

Ross, Michael B.; Ku, Jessie C.; Lee, Byeongdu; ...

2016-02-05

In this study, mixed silver and gold plasmonic nanoparticle architectures are synthesized using DNA-programmable assembly, unveiling exquisitely tunable optical properties that are predicted and explained both by effective thin-film models and explicit electrodynamic simulations. These data demonstrate that the manner and ratio with which multiple metallic components are arranged can greatly alter optical properties, including tunable color and asymmetric reflectivity behavior of relevance for thin-film applications.

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.

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

Guetaz, Laure; Lopez-Haro, M.; Escribano, S.

Investigation of membrane/electrode assembly (MEA) microstructure has become an essential step to optimize the MEA components and manufacturing processes or to study the MEA degradation. For these investigations, transmission electron microscopy (TEM) is a tool of choice as it provides direct imaging of the different components. TEM is then widely used for analyzing the catalyst nanoparticles and their carbon support. However, the ionomer inside the electrode is more difficult to be imaged. The difficulties come from the fact that the ionomer forms an ultrathin layer surrounding the carbon particles and in addition, these two components, having similar density, present nomore » difference in contrast. In this paper, we show how the recent progresses in TEM techniques as spherical aberration (Cs) corrected HRTEM, electron tomography and X-EDS elemental mapping provide new possibilities for imaging this ionomer network and consequently to study its degradation.« less

Physicochemical characterization of engineered nanoparticles under physiological conditions: effect of culture media components and particle surface coating.

PubMed

Fatisson, Julien; Quevedo, Ivan R; Wilkinson, Kevin J; Tufenkji, Nathalie

2012-03-01

The use of engineered nanoparticles (ENPs) in commercial products has increased substantially over the last few years. Some research has been conducted in order to determine whether or not such materials are cytotoxic, but questions remain regarding the role that physiological media and sera constituents play in ENP aggregation or stabilization. In this study, several characterization methods were used to evaluate the particle size and surface potential of 6 ENPs suspended in a number of culture media and in the presence of different culture media constituents. Dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS) were employed for size determinations. Results were interpreted on the basis of ENP surface potentials evaluated from particle electrophoretic mobilities (EPM). Measurements made after 24h of incubation at 37°C showed that the cell culture medium constituents had only moderate impact on the physicochemical properties of the ENP, although incubation in bovine serum albumin destabilized the colloidal system. In contrast, most of the serum proteins increased colloidal stabilization. Moreover, the type of ENP surface modification played a significant role in ENP behavior whereby the complexity of interactions between the ENPs and the medium components generally decreased with increasing complexity of the particle surface. This investigation emphasizes the importance of ENP characterization under conditions that are representative of cell culture media or physiological conditions for improved assessments of nanoparticle cytotoxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

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

Yang, Li; Zhu, Zihua; Yu, Xiao-Ying

In this study, we report new results of in situ study of 5 nm goat anti-mouse IgG gold nanoparticles in a novel portable vacuum compatible microfluidic device using scanning electron microscope (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The unique feature of the liquid flow cell is that the detection window is open to the vacuum allowing direct probing of the liquid surface. The flow cell is composed of a silicon nitride (SiN) membrane and polydimethylsiloxane (PDMS), and it is fully compatible with vacuum operations for surface analysis. The aperture can be drilled through the 100 nm SiN membranemore » using a focused ion beam. Characteristic signals of the conjugated gold nanoparticles were successfully observed through the aperture by both energy-dispersive X-ray spectroscopy (EDX) in SEM and ToF-SIMS. Comparison was also made among wet samples, dry samples, and liquid sample in the flow cell using SEM/EDX. Stronger gold signal can be observed in our novel portable device by SEM/EDX compared with the wet or dry samples, respectively. Our results indicate that analyses of the nanoparticle components are better made in their native liquid environment. This is made possible using our unique microfluidic flow cell.« less

Characterization of Nanoparticle Aggregation in Biologically Relevant Fluids

NASA Astrophysics Data System (ADS)

McEnnis, Kathleen; Lahann, Joerg

Nanoparticles (NPs) are often studied as drug delivery vehicles, but little is known about their behavior in blood once injected into animal models. If the NPs aggregate in blood, they will be shunted to the liver or spleen instead of reaching the intended target. The use of animals for these experiments is costly and raises ethical questions. Typically dynamic light scattering (DLS) is used to analyze aggregation behavior, but DLS cannot be used because the components of blood also scatter light. As an alternative, a method of analyzing NPs in biologically relevant fluids such as blood plasma has been developed using nanoparticle tracking analysis (NTA) with fluorescent filters. In this work, NTA was used to analyze the aggregation behavior of fluorescent polystyrene NPs with different surface modifications in blood plasma. It was expected that different surface chemistries on the particles will change the aggregation behavior. The effect of the surface modifications was investigated by quantifying the percentage of NPs in aggregates after addition to blood plasma. The use of this characterization method will allow for better understanding of particle behavior in the body, and potential problems, specifically aggregation, can be addressed before investing in in vivo studies.

Incredible antibacterial activity of noble metal functionalized magnetic core-zeolitic shell nanostructures.

PubMed

Padervand, M; Janatrostami, S; Karanji, A Kiani; Gholami, M R

2014-02-01

Functionalized magnetic core-zeolitic shell nanostructures were prepared by hydrothermal and coprecipitation methods. The products were characterized by Vibrating Sample Magnetometer (VSM), X-ray powder diffraction (XRD), Fourier Transform Infrared (FTIR) spectra, nitrogen adsorption-desorption isotherms, and Transmission Electron Microscopy (TEM). The growth of mordenite nanoparticles on the surface of silica coated nickel ferrite nanoparticles in the presence of organic templates was also confirmed. Antibacterial activity of the prepared nanostructures was investigated by the inactivation of Escherichia coli as a gram negative bacterium. A new mechanism was proposed for inactivation of E. coli over the prepared samples. In addition, the Minimum Inhibitory Concentration (MIC) and reuse ability were studied. TEM images of the destroyed cell wall after the treatment time were performed to illustrate the inactivation mechanism. According to the experimental results, the core-shell nanostructures which were modified by organic agents and then functionalized with noble metal nanoparticles were the most active. The interaction of the noble metals with the organic components on the surface of nanostructures was studied theoretically and the obtained results were used to interpret the experimental results. © 2013. Published by Elsevier B.V. All rights reserved.

Biochemical component identification by plasmonic improved whispering gallery mode optical resonance based sensor

NASA Astrophysics Data System (ADS)

Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Saetchnikov, Anton V.; Schweiger, Gustav; Ostendorf, Andreas

2014-05-01

Experimental data on detection and identification of variety of biochemical agents, such as proteins, microelements, antibiotic of different generation etc. in both single and multi component solutions under varied in wide range concentration analyzed on the light scattering parameters of whispering gallery mode optical resonance based sensor are represented. Multiplexing on parameters and components has been realized using developed fluidic sensor cell with fixed in adhesive layer dielectric microspheres and data processing. Biochemical component identification has been performed by developed network analysis techniques. Developed approach is demonstrated to be applicable both for single agent and for multi component biochemical analysis. Novel technique based on optical resonance on microring structures, plasmon resonance and identification tools has been developed. To improve a sensitivity of microring structures microspheres fixed by adhesive had been treated previously by gold nanoparticle solution. Another technique used thin film gold layers deposited on the substrate below adhesive. Both biomolecule and nanoparticle injections caused considerable changes of optical resonance spectra. Plasmonic gold layers under optimized thickness also improve parameters of optical resonance spectra. Biochemical component identification has been also performed by developed network analysis techniques both for single and for multi component solution. So advantages of plasmon enhancing optical microcavity resonance with multiparameter identification tools is used for development of a new platform for ultra sensitive label-free biomedical sensor.

Mechanistic insights into the one-pot synthesis of propargylamines from terminal alkynes and amines in chlorinated solvents catalyzed by gold compounds and nanoparticles.

PubMed

Aguilar, David; Contel, Maria; Urriolabeitia, Esteban P

2010-08-09

Propargylamines can be obtained from secondary amines and terminal alkynes in chlorinated solvents by a three- and two-component synthesis catalyzed by gold compounds and nanoparticles (Au-NP) under mild conditions. The use of dichloromethane allows for the activation of two C-Cl bonds and a clean transfer of the methylene fragment to the final product. The scope of the reaction as well as the influence of different gold(III) cycloaurated complexes and salts has been investigated. The involvement of gold nanoparticles generated in situ in the process is discussed and a plausible reaction mechanism is proposed on the basis of the data obtained.

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

Hachtel, J. A.; Yu, S.; Lupini, A. R.

The combination of iron oxide and gold in a single nanoparticle results in both magnetic and plasmonic properties that can stimulate novel applications in bio-sensing, medical imaging, or therapeutics. Microwave assisted heating allows the fabrication of multi-component, multi-functional nanostructures by promoting selective heating at desired sites. Recently, we reported a microwave-assisted polyol route yielding gold nanotriangles decorated with iron oxide nanoparticles. Here, we present an in-depth microstructural and compositional characterization of the system by using scanning transmission electron microscopy (STEM) and electron energy loss (EELS) spectroscopy. A method to remove the iron oxide nanoparticles from the gold nanocrystals and somemore » insights on crystal nucleation and growth mechanisms are also provided.« less

Nanoparticle detection using dual-phase interferometry

PubMed Central

Deutsch, Bradley; Beams, Ryan; Novotny, Lukas

2013-01-01

Detection and identification of nanoparticles is of growing interest in atmospheric monitoring, medicine and semiconductor manufacturing. While elastic light scattering with interferometric detection provides good sensitivity to single particles, active optical components prevent scalability realistic sizes for deployment in the field or clinic. Here we report on a simple phase-sensitive nanoparticle detection scheme with no active optical elements. Two measurements are taken simultaneously, allowing amplitude and phase to be decoupled. We demonstrate detection of 25 nm Au particles in liquid in Δt ~ 1 ms with a signal-to-noise ratio of 37. Such performance makes it possible to detect nanoscale contaminants or larger proteins in real time without the need of artificial labeling. PMID:20830181

Selenium uptake and assessment of the biochemical changes in Arthrospira (Spirulina) platensis biomass during the synthesis of selenium nanoparticles.

PubMed

Zinicovscaia, I; Chiriac, T; Cepoi, L; Rudi, L; Culicov, O; Frontasyeva, M; Rudic, V

2017-01-01

The process of selenium uptake by biomass of the cyanobacterium Arthrospira (Spirulina) platensis was investigated by neutron activation analysis at different selenium concentrations in solution and at different contact times. Experimental data showed good fit with the Freundlich adsorption isotherm model, with a regression coefficient value of 0.99. In terms of absorption dependence on time, the maximal selenium content was adsorbed in the first 5 min of interaction without significant further changes. It was also found that A. platensis biomass forms spherical selenium nanoparticles. Biochemical analysis was used to assess the changes in the main components of spirulina biomass (proteins, lipids, carbohydrates, and phycobilin) during nanoparticle formation.

The role of interfacial metal silicates on the magnetism in FeCo/SiO{sub 2} and Fe{sub 49%}Co{sub 49%}V{sub 2%}/SiO{sub 2} core/shell nanoparticles

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

Desautels, R. D., E-mail: rddesautels@physics.umanitoba.ca; Toyota Research Institute of North America, Ann Arbor, Michigan 48169; Freeland, J. W.

2015-05-07

We have investigated the role of spontaneously formed interfacial metal silicates on the magnetism of FeCo/SiO{sub 2} and Fe{sub 49%}Co{sub 49%}V{sub 2%}/SiO{sub 2} core/shell nanoparticles. Element specific x-ray absorption and photoelectron spectroscopy experiments have identified the characteristic spectral features of metallic iron and cobalt from within the nanoparticle core. In addition, metal silicates of iron, cobalt, and vanadium were found to have formed spontaneously at the interface between the nanoparticle core and silica shell. X-ray magnetic circular dichroism experiments indicated that the elemental magnetism was a result of metallic iron and cobalt with small components from the iron, cobalt, andmore » vanadium silicates. Magnetometry experiments have shown that there was no exchange bias loop shift in the FeCo nanoparticles; however, exchange bias from antiferromagnetic vanadium oxide was measured in the V-doped nanoparticles. These results showed clearly that the interfacial metal silicates played a significant role in the magnetism of these core/shell nanoparticles, and that the vanadium percolated from the FeCo-cores into the SiO{sub 2}-based interfacial shell.« less

Photoresponsive lipid-polymer hybrid nanoparticles for controlled doxorubicin release

NASA Astrophysics Data System (ADS)

Yao, Cuiping; Wu, Ming; Zhang, Cecheng; Lin, Xinyi; Wei, Zuwu; Zheng, Youshi; Zhang, Da; Zhang, Zhenxi; Liu, Xiaolong

2017-06-01

Currently, photoresponsive nanomaterials are particularly attractive due to their spatial and temporal controlled drug release abilities. In this work, we report a photoresponsive lipid-polymer hybrid nanoparticle for remote controlled delivery of anticancer drugs. This hybrid nanoparticle comprises three distinct functional components: (i) a poly(D,L-lactide-co-glycolide) (PLGA) core to encapsulate doxorubicin; (ii) a soybean lecithin monolayer at the interface of the core and shell to act as a molecular fence to prevent drug leakage; (iii) a photoresponsive polymeric shell with anti-biofouling properties to enhance nanoparticle stability, which could be detached from the nanoparticle to trigger the drug release via a decrease in the nanoparticle’s stability under light irradiation. In vitro results revealed that this core-shell nanoparticle had excellent light-controlled drug release behavior (76% release with light irradiation versus 10% release without light irradiation). The confocal microscopy and flow cytometry results also further demonstrated the light-controlled drug release behavior inside the cancer cells. Furthermore, a CCK8 assay demonstrated that light irradiation could significantly improve the efficiency of killing cancer cells. Meanwhile, whole-animal fluorescence imaging of a tumor-bearing mouse also confirmed that light irradiation could trigger drug release in vivo. Taken together, our data suggested that a hybrid nanoparticle could be a novel light controlled drug delivery system for cancer therapy.

Fabrication of aligned magnetic nanoparticles using tobamoviruses.

PubMed

Kobayashi, Mime; Seki, Munetoshi; Tabata, Hitoshi; Watanabe, Yuichiro; Yamashita, Ichiro

2010-03-10

We used genetically modified tube-shaped tobamoviruses to produce 3 nm aligned magnetic nanoparticles. Amino acid residues facing the central channel of the virus were modified to increase the number of nucleation sites. Energy dispersive X-ray spectroscopy and superconducting quantum interference device analysis suggest that the particles consisted of Co-Pt alloy. The use of tobamovirus mutants is a promising approach to making a variety of components that can be applied to fabricate nanometer-scaled electronic devices.

Peptides for Specific Intracellular Delivery and Targeting of Nanoparticles: Implications for Developing Nanoparticle-Mediated Drug Delivery

DTIC Science & Technology

2010-01-01

for selective delivery of therapeutics and imaging agents to the tumour vasculature. Drug Resist. Update 8(6), 381–402 (2005). 89 Smith BR, Cheng Z...component can be realized. Select examples from the literature have already demonstrated the feasibility of generating hybrid NP–peptide constructs in...peptide-mediated delivery of NP-based imaging agents (fluorescence and magnetic resonance), drug-delivery vehicles, therapeutic proteins and nucleic

Core-shell nanocapsules stabilized by single-component polymer and nanoparticles for magneto-chemotherapy/hyperthermia with multiple drugs.

PubMed

Hu, Shang-Hsiu; Liao, Bang-Jie; Chiang, Chin-Sheng; Chen, Po-Jung; Chen, I-Wei; Chen, San-Yuan

2012-07-17

Iron-oxide-containing double emulsion capsules carrying both hydrophilic and hydrophobic therapeutic molecules can deliver drugs and energy on demand in vivo. Magneto-chemotherapy/hyperthermia involves a burst-like release of hydrophilic doxorubicin and hydrophobic paclitaxel, remotely triggered by a high frequency magnetic field, which also releases energy via internalized iron oxide nanoparticles, all contributing to cell kill. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

AlgiMatrix™-Based 3D Cell Culture System as an In Vitro Tumor Model: An Important Tool in Cancer Research.

PubMed

Godugu, Chandraiah; Singh, Mandip

2016-01-01

Routinely used two-dimensional cell culture-based models often fail while translating the observations into in vivo models. This setback is more common in cancer research, due to several reasons. The extracellular matrix and cell-to-cell interactions are not present in two-dimensional (2D) cell culture models. Diffusion of drug molecules into cancer cells is hindered by barriers of extracellular components in in vivo conditions, these barriers are absent in 2D cell culture models. To better mimic or simulate the in vivo conditions present in tumors, the current study used the alginate based three-dimensional cell culture (AlgiMatrix™) model, which resembles close to the in vivo tumor models. The current study explains the detailed protocols involved in AlgiMatrix™ based in vitro non-small-cell lung cancer (NSCLC) models. The suitability of this model was studied by evaluating, cytotoxicity, apoptosis, and penetration of nanoparticles into the in vitro tumor spheroids. This study also demonstrated the effect of EphA2 receptor targeted docetaxel-loaded nanoparticles on MDA-MB-468 TNBC cell lines. The methods section is subdivided into three subsections such as (1) preparation of AlgiMatrix™-based 3D in vitro tumor models and cytotoxicity assays, (2) free drug and nanoparticle uptake into spheroid studies, and (3) western blot, IHC, and RT-PCR studies.

Current advances in precious metal core-shell catalyst design.

PubMed

Wang, Xiaohong; He, Beibei; Hu, Zhiyu; Zeng, Zhigang; Han, Sheng

2014-08-01

Precious metal nanoparticles are commonly used as the main active components of various catalysts. Given their high cost, limited quantity, and easy loss of catalytic activity under severe conditions, precious metals should be used in catalysts at low volumes and be protected from damaging environments. Accordingly, reducing the amount of precious metals without compromising their catalytic performance is difficult, particularly under challenging conditions. As multifunctional materials, core-shell nanoparticles are highly important owing to their wide range of applications in chemistry, physics, biology, and environmental areas. Compared with their single-component counterparts and other composites, core-shell nanoparticles offer a new active interface and a potential synergistic effect between the core and shell, making these materials highly attractive in catalytic application. On one hand, when a precious metal is used as the shell material, the catalytic activity can be greatly improved because of the increased surface area and the closed interfacial interaction between the core and the shell. On the other hand, when a precious metal is applied as the core material, the catalytic stability can be remarkably improved because of the protection conferred by the shell material. Therefore, a reasonable design of the core-shell catalyst for target applications must be developed. We summarize the latest advances in the fabrications, properties, and applications of core-shell nanoparticles in this paper. The current research trends of these core-shell catalysts are also highlighted.

A nanometre-scale electronic switch consisting of a metal cluster and redox-addressable groups.

PubMed

Gittins, D I; Bethell, D; Schiffrin, D J; Nichols, R J

2000-11-02

So-called bottom-up fabrication methods aim to assemble and integrate molecular components exhibiting specific functions into electronic devices that are orders of magnitude smaller than can be fabricated by lithographic techniques. Fundamental to the success of the bottom-up approach is the ability to control electron transport across molecular components. Organic molecules containing redox centres-chemical species whose oxidation number, and hence electronic structure, can be changed reversibly-support resonant tunnelling and display promising functional behaviour when sandwiched as molecular layers between electrical contacts, but their integration into more complex assemblies remains challenging. For this reason, functionalized metal nanoparticles have attracted much interest: they exhibit single-electron characteristics (such as quantized capacitance charging) and can be organized through simple self-assembly methods into well ordered structures, with the nanoparticles at controlled locations. Here we report scanning tunnelling microscopy measurements showing that organic molecules containing redox centres can be used to attach metal nanoparticles to electrode surfaces and so control the electron transport between them. Our system consists of gold nanoclusters a few nanometres across and functionalized with polymethylene chains that carry a central, reversibly reducible bipyridinium moiety. We expect that the ability to electronically contact metal nanoparticles via redox-active molecules, and to alter profoundly their tunnelling properties by charge injection into these molecules, can form the basis for a range of nanoscale electronic switches.

Magnetically Recoverable and Reusable Antimicrobial Nanocomposite Based on Activated Carbon, Magnetite Nanoparticles, and Silver Nanoparticles for Water Disinfection

DOE PAGES

Furlan, Ping; Fisher, Adam; Furlan, Alexander; ...

2017-06-06

Recent advancements in nanotechnology have led to the development of innovative, low-cost and highly efficient water disinfection technologies that may replace or enhance the conventional methods. In this study, we introduce a novel procedure for preparing a bifunctional activated carbon nanocomposite in which nanoscale-sized magnetic magnetite and antimicrobial silver nanoparticles are incorporated (MACAg). The antimicrobial efficacy of the nanocomposite was tested against Escherichia coli (E. coli). MACAg (0.5 g, 0.04% Ag) was found to remove and kill 10 6–10 7 CFU (colony-forming units) in 30 min via a shaking test and the removing and killing rate of the nanocomposites increasedmore » with increasing silver content and decreased with increasing CFU. The inhibition zone tests revealed, among the relevant components, only Ag nanoparticles and Ag + ions showed antimicrobial activities. The MACAg was easily recoverable from treated water due to its magnetic properties and was able to remove and kill 10 6 CFU after multiple-repeated use. The MACAg nanocomposite also demonstrated its feasibility and applicability for treating a surface water containing 10 5 CFU. Combining low cost due to easy synthesis, recoverability, and reusability with high antimicrobial efficiency, MACAg may provide a promising water disinfection technology that will find wide applications.« less

Magnetically Recoverable and Reusable Antimicrobial Nanocomposite Based on Activated Carbon, Magnetite Nanoparticles, and Silver Nanoparticles for Water Disinfection

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

Furlan, Ping; Fisher, Adam; Furlan, Alexander

Recent advancements in nanotechnology have led to the development of innovative, low-cost and highly efficient water disinfection technologies that may replace or enhance the conventional methods. In this study, we introduce a novel procedure for preparing a bifunctional activated carbon nanocomposite in which nanoscale-sized magnetic magnetite and antimicrobial silver nanoparticles are incorporated (MACAg). The antimicrobial efficacy of the nanocomposite was tested against Escherichia coli (E. coli). MACAg (0.5 g, 0.04% Ag) was found to remove and kill 10 6–10 7 CFU (colony-forming units) in 30 min via a shaking test and the removing and killing rate of the nanocomposites increasedmore » with increasing silver content and decreased with increasing CFU. The inhibition zone tests revealed, among the relevant components, only Ag nanoparticles and Ag + ions showed antimicrobial activities. The MACAg was easily recoverable from treated water due to its magnetic properties and was able to remove and kill 10 6 CFU after multiple-repeated use. The MACAg nanocomposite also demonstrated its feasibility and applicability for treating a surface water containing 10 5 CFU. Combining low cost due to easy synthesis, recoverability, and reusability with high antimicrobial efficiency, MACAg may provide a promising water disinfection technology that will find wide applications.« less

In situ TEM study of lithiation behavior of silicon nanoparticles attached to and embedded in a carbon matrix.

PubMed

Gu, Meng; Li, Ying; Li, Xiaolin; Hu, Shenyang; Zhang, Xiangwu; Xu, Wu; Thevuthasan, Suntharampillai; Baer, Donald R; Zhang, Ji-Guang; Liu, Jun; Wang, Chongmin

2012-09-25

Rational design of silicon and carbon nanocomposite with a special topological feature has been demonstrated to be a feasible way for mitigating the capacity fading associated with the large volume change of silicon anode in lithium ion batteries. Although the lithiation behavior of silicon and carbon as individual components has been well understood, lithium ion transport behavior across a network of silicon and carbon is still lacking. In this paper, we probe the lithiation behavior of silicon nanoparticles attached to and embedded in a carbon nanofiber using in situ TEM and continuum mechanical calculation. We found that aggregated silicon nanoparticles show contact flattening upon initial lithiation, which is characteristically analogous to the classic sintering of powder particles by a neck-growth mechanism. As compared with the surface-attached silicon particles, particles embedded in the carbon matrix show delayed lithiation. Depending on the strength of the carbon matrix, lithiation of the embedded silicon nanoparticles can lead to the fracture of the carbon fiber. These observations provide insights on lithium ion transport in the network-structured composite of silicon and carbon and ultimately provide fundamental guidance for mitigating the failure of batteries due to the large volume change of silicon anodes.

Characterisation and potential migration of silver nanoparticles from commercially available polymeric food contact materials.

PubMed

Addo Ntim, Susana; Thomas, Treye A; Begley, Timothy H; Noonan, Gregory O

2015-01-01

The potential for consumer exposure to nano-components in food contact materials (FCMs) is dependent on the migration of nanomaterials into food. Therefore, characterising the physico-chemical properties and potential for migration of constituents is an important step in assessing the safety of FCMs. A number of commercially available food storage products, purchased domestically within the United States and internationally, that claim to contain nanosilver were evaluated. The products were made of polyethylene, polypropylene and polyphenylene ether sulfone and all contained silver (0.001-36 mg kg(-1) of polymer). Silver migration was measured under various conditions, including using 3% acetic acid and water as food simulants. Low concentrations (sub-ppb levels) of silver were detected in the migration studies generally following a trend characterised by a surface desorption phenomenon, where the majority of the silver migration occurred in the first of three consecutive exposures. Silver nanoparticles were not detected in food simulants, suggesting that the silver migration may be due solely to ionic silver released into solution from oxidation of the silver nanoparticle surface. The absence of detectable silver nanoparticles was consistent with expectations from a physico-chemical view point. For the products tested, current USFDA guidance for evaluating migration from FCMs was applicable.

Oxidation-induced structural changes in sub-nanometer platinum supported on alumina

DOE PAGES

DeBusk, Melanie Moses; Allard, Jr, Lawrence Frederick; Blom, Douglas Allen; ...

2015-06-26

Platinum supported on alumina is an essential component of emission treatment catalysts used in transportation. Theoretical, experimental, and mechanistic aspects of platinum particles supported on a variety of supports have been extensively studied; however, available experimental information on the behavior of single vs. sub-nanometer platinum is extremely limited. To bridge the knowledge gap between single supported platinum and well-formed supported platinum nanoparticles, we have carried out synthesis, characterization, and CO and NO oxidation studies of sub-nanometer platinum supported on α, θ, and γ-Al 2O 3 and monitored changes in structure upon exposure to CO and NO oxidation conditions. Furthermore, wemore » find that sub-nanometer Pt is highly effective for CO oxidation due to high platinum dispersion but is not very efficient as NO oxidation catalyst. Lastly, sub-nanometer platinum agglomerates rapidly under CO or NO oxidation conditions to form nanoparticles.« less

Intracellular Trafficking of Silicon Particles and Logic-Embedded Vectors

PubMed Central

Ferrati, Silvia; Mack, Aaron; Chiappini, Ciro; Liu, Xuewu; Bean, Andrew J.; Ferrari, Mauro; Serda, Rita E.

2010-01-01

Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon particles to be optimized for specific applications such as vascular targeting and avoidance of biological barriers commonly found between the site of drug injection and the final destination. In this study, the intracellular trafficking of unloaded carrier silicon particles and carrier particles loaded with secondary iron oxide nanoparticles was investigated. Following cellular uptake, membrane-encapsulated silicon particles migrated to the perinuclear region of the cell by a microtubule-driven mechanism. Surface charge, shape (spherical and hemispherical) and size (1.6 and 3.2 μm) of the particle did not alter the rate of migration. Maturation of the phagosome was associated with an increase in acidity and acquisition of markers of late endosomes and lysosomes. Cellular uptake of iron oxide nanoparticle-loaded silicon particles resulted in sorting of the particles and trafficking to unique destinations. The silicon carriers remained localized in phagosomes, while the second stage iron oxide nanoparticles were sorted into multi-vesicular bodies that dissociated from the phagosome into novel membrane-bound compartments. Release of iron from the cells may represent exocytosis of iron oxide nanoparticle-loaded vesicles. These results reinforce the concept of multi-functional nanocarriers, in which different particles are able to perform specific tasks, in order to deliver single- or multi-component payloads to specific sub-cellular compartments. PMID:20820744

Ultrafast Pulse Generation in an Organic Nanoparticle-Array Laser.

PubMed

Daskalakis, Konstantinos S; Väkeväinen, Aaro I; Martikainen, Jani-Petri; Hakala, Tommi K; Törmä, Päivi

2018-04-11

Nanoscale coherent light sources offer potentially ultrafast modulation speeds, which could be utilized for novel sensors and optical switches. Plasmonic periodic structures combined with organic gain materials have emerged as promising candidates for such nanolasers. Their plasmonic component provides high intensity and ultrafast nanoscale-confined electric fields, while organic gain materials offer fabrication flexibility and a low acquisition cost. Despite reports on lasing in plasmonic arrays, lasing dynamics in these structures have not been experimentally studied yet. Here we demonstrate, for the first time, an organic dye nanoparticle-array laser with more than a 100 GHz modulation bandwidth. We show that the lasing modulation speed can be tuned by the array parameters. Accelerated dynamics is observed for plasmonic lasing modes at the blue side of the dye emission.

Magnetic study of Co-doped CdSe nanoparticles

NASA Astrophysics Data System (ADS)

Das, Sayantani; Banerjee, Sourish; Sinha, T. P.

2018-04-01

Cobalt (2 %, 5 % and 10 %) doped cadmium selenide (CdSe) nanoparticles have been synthesized by soft chemical route. The XRD pattern shows the cubic structure of the sample. Crystallization temperature of the samples is calculated using differential scanning calorimeter. The average particle size of all the samples is found to be ˜ 25 nm. Field dependent (M-H) and temperature dependent (M-T) magnetization explains the presence of ferromagnetic components in the samples at room temperature and low temperature. In order to estimate the antiferromagnetic coupling among the doped TM atoms, an M-T measurement at 500 Oe has been carried out under zero field cooled (ZFC) and field cooled (FC) conditions and Curie-Weiss temperature θ of the samples has been estimated from 1/χ vs T plots.

Nanoparticles that Communicate In Vivo to Amplify Tumour Targeting

PubMed Central

von Maltzahn, Geoffrey; Park, Ji-Ho; Lin, Kevin Y.; Singh, Neetu; Schwöppe, Christian; Mesters, Rolf; Berdel, Wolfgang E.; Ruoslahti, Erkki; Sailor, Michael J.; Bhatia, Sangeeta N.

2012-01-01

Nanomedicines have enormous potential to improve the precision of cancer therapy, yet our ability to efficiently home these materials to regions of disease in vivo remains very limited. Inspired by the ability for communication to improve targeting in biological systems, such inflammatory cell recruitment to sites of disease, we construct systems where synthetic biological and nanotechnological components communicate to amplify disease targeting in vivo. These systems are composed of ‘Signalling’ modules (nanoparticles or engineered proteins) that target tumours and then locally active the coagulation cascade to broadcast tumour location to clot-targeted ‘Receiving’ nanoparticles in circulation that carry a diagnostic or therapeutic cargo, thereby amplifying their delivery. We show that communicating nanoparticle systems can be composed from multiple types of Signalling and Receiving modules, can transmit information via multiple molecular pathways in coagulation, can operate autonomously, and can target over 40-fold higher doses of chemotherapeutics to tumours than non-communicating controls. PMID:21685903

Assay to detect lipid peroxidation upon exposure to nanoparticles.

PubMed

Potter, Timothy M; Neun, Barry W; Stern, Stephan T

2011-01-01

This chapter describes a method for the analysis of human hepatocarcinoma cells (HEP G2) for lipid peroxidation products, such as malondialdehyde (MDA), following treatment with nanoparticle formulations. Oxidative stress has been identified as a likely mechanism of nanoparticle toxicity, and cell-based in vitro systems for evaluation of nanoparticle-induced oxidative stress are widely considered to be an important component of biocompatibility screens. The products of lipid peroxidation, lipid hydroperoxides, and aldehydes, such as MDA, can be measured via a thiobarbituric acid reactive substances (TBARS) assay. In this assay, which can be performed in cell culture or in cell lysate, MDA combines with thiobarbituric acid (TBA) to form a fluorescent adduct that can be detected at an excitation wavelength of 530 nm and an emission wavelength of 550 nm. The results are then expressed as MDA equivalents, normalized to total cellular protein (determined by Bradford assay).

In-vitro nanodiagnostic platform through nanoparticles and DNA-RNA nanotechnology.

PubMed

Chan, Ki; Ng, Tzi Bun

2015-04-01

Nanocomposites containing nanoparticles or nanostructured domains exhibit an even higher degree of material complexity that leads to an extremely high variability of nanostructured materials. This review introduces analytical concepts and techniques for nanomaterials and derives recommendations for a qualified selection of characterization techniques for specific types of samples, and focuses the characterization of nanoparticles and their agglomerates or aggregates. In addition, DNA nanotechnology and the more recent newcomer RNA nanotechnology have achieved almost an advanced status among nanotechnology researchers¸ therefore, the core features, potential, and significant challenges of DNA nanotechnology are also highlighted as a new discipline. Moreover, nanobiochips made by nanomaterials are rapidly emerging as a new paradigm in the area of large-scale biochemical analysis. The use of nanoscale components enables higher precision in diagnostics while considerably reducing the cost of the platform that leads this review to explore the use of nanoparticles, nanomaterials, and other bionanotechnologies for its application to nanodiagnostics in-vitro.

Core-shell structure disclosed in self-assembled Cu-Ag nanoalloy particles

NASA Astrophysics Data System (ADS)

Tchaplyguine, M.; Andersson, T.; Zhang, Ch.; Björneholm, O.

2013-03-01

Core-shell segregation of copper and silver in self-assembled, free nanoparticles is established by means of photoelectron spectroscopy in a wide range of relative Cu-Ag concentrations. These conclusions are based on the analysis of the photon-energy-dependent changes of the Cu 3d and Ag 4d photoelectron spectra. The nanoparticles are formed from mixed Cu-Ag atomic vapor created by magnetron sputtering of a bimetallic sample in a gas-aggregation cluster source. Even at similar Cu and Ag fractions in the primary vapor the surface of the nanoparticles is dominated by silver. Only at low Ag concentration copper appears on the surface of nanoparticles. For the latter case, a threefold decrease in the Ag 4d spin-orbit splitting has been detected. The specific component distribution and electronic structure changes are discussed in connection with the earlier results on Cu-Ag macroscopic and surface alloys.

SIMS depth profiling of working environment nanoparticles

NASA Astrophysics Data System (ADS)

Konarski, P.; Iwanejko, I.; Mierzejewska, A.

2003-01-01

Morphology of working environment nanoparticles was analyzed using sample rotation technique in secondary ion mass spectrometry (SIMS). The particles were collected with nine-stage vacuum impactor during gas tungsten arc welding (GTAW) process of stainless steel and shielded metal arc welding (SMAW) of mild steel. Ion erosion of 300-400 nm diameter nanoparticles attached to indium substrate was performed with 2 keV, 100 μm diameter, Ar + ion beam at 45° ion incidence and 1 rpm sample rotation. The results show that both types of particles have core-shell morphology. A layer of fluorine, chlorine and carbon containing compounds covers stainless steel welding fume particles. The cores of these particles are enriched in iron, manganese and chromium. Outer shell of mild steel welding fume particles is enriched in carbon, potassium, chlorine and fluorine, while the deeper layers of these nanoparticles are richer in main steel components.

Nanospace-Mediated Self-Organization of Nanoparticles in Flexible Porous Polymer Templates.

PubMed

Kuroda, Yoshiyuki; Muto, Itaru; Shimojima, Atsushi; Wada, Hiroaki; Kuroda, Kazuyuki

2017-09-12

Self-organization is a fundamental process for the construction of complex hierarchically ordered nanostructures, which are widespread in biological systems. However, precise control of size, shape, and surface properties is required for self-organization of nanoparticles. Here, we demonstrate a novel self-organization phenomenon mediated by flexible nanospaces in templates. Inorganic nanoparticles (e.g., silica, zirconia, and titania) are deposited in porous polymer thin films with randomly distributed pores on the surface, leaving a partially filled nanospace in each pore. Heating at temperatures beyond the glass transition temperature of the template leads to self-organization of the inorganic nanoparticles into one-dimensional chainlike networks. The self-organization is mediated by the deformation and fusion of the residual nanospaces, and it can be rationally controlled by sequential heat treatments. These results show that a nanospace, defined by the nonexistence of matter, interacts indirectly with matter and can be used as a component of self-organization systems.

Selective transformations between nanoparticle superlattices via the reprogramming of DNA-mediated interactions

DOE PAGES

Zhang, Yugang; Pal, Suchetan; Srinivasan, Babji; ...

2015-05-25

The rapid development of self-assembly approaches has enabled the creation of materials with desired organization of nanoscale components. However, achieving dynamic control, wherein the system can be transformed on demand into multiple entirely different states, is typically absent in atomic and molecular systems and has remained elusive in designed nanoparticle systems. Here, we demonstrate with in situ small-angle x-ray scattering that, by using DNA strands as inputs, the structure of a three-dimensional lattice of DNA-coated nanoparticles can be switched from an initial 'mother' phase into one of multiple 'daughter' phases. The introduction of different types of re-programming DNA strands modifiesmore » the DNA shells of the nanoparticles within the superlattice, thereby shifting interparticle interactions to drive the transformation into a particular daughter phase. We mapped quantitatively with free-energy calculations the selective re-programming of interactions onto the observed daughter phases.« less

Nanoparticles that communicate in vivo to amplify tumour targeting

NASA Astrophysics Data System (ADS)

von Maltzahn, Geoffrey; Park, Ji-Ho; Lin, Kevin Y.; Singh, Neetu; Schwöppe, Christian; Mesters, Rolf; Berdel, Wolfgang E.; Ruoslahti, Erkki; Sailor, Michael J.; Bhatia, Sangeeta N.

2011-07-01

Nanomedicines have enormous potential to improve the precision of cancer therapy, yet our ability to efficiently home these materials to regions of disease in vivo remains very limited. Inspired by the ability of communication to improve targeting in biological systems, such as inflammatory-cell recruitment to sites of disease, we construct systems where synthetic biological and nanotechnological components communicate to amplify disease targeting in vivo. These systems are composed of ‘signalling’ modules (nanoparticles or engineered proteins) that target tumours and then locally activate the coagulation cascade to broadcast tumour location to clot-targeted ‘receiving’ nanoparticles in circulation that carry a diagnostic or therapeutic cargo, thereby amplifying their delivery. We show that communicating nanoparticle systems can be composed of multiple types of signalling and receiving modules, can transmit information through multiple molecular pathways in coagulation, can operate autonomously and can target over 40 times higher doses of chemotherapeutics to tumours than non-communicating controls.

The Chemical Composition and Structure of Supported Sulfated Zirconia with Regulated Size Nanoparticles

NASA Astrophysics Data System (ADS)

Kanazhevskiy, V. V.; Shmachkova, V. P.; Kotsarenko, N. S.; Kochubey, D. I.; Vedrine, J. C.

2007-02-01

A set of model skeletal isomerization catalysts — sulfated zirconia nanoparticles of controlled thickness anchored on different supports — was prepared using colloidal solutions of Zr salt on titania as support. The nanoparticles of zirconia (1-5 nm) are epitaxially connected to the support surface, with S/Zr ratio equals to 1.3-1.5. It was shown by EXAFS that nanoparticles of non-stoichiometric zirconium sulfate Zr(SO4)1+x, where x<0.5, are formed on the support surface. Its structure looks like half-period shifted counterdirected chains built-up by zirconium atoms linked by triangle pyramids of sulfate groups. Considering catalytic data of skeletal n-butane isomerisation at 150°C, one can suggest that these species behave as the active component of sulfated zirconia. They are formed in subsurface layers as zirconium hydroxide undergoes sulfation followed by thermal treatment.

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles

PubMed Central

Yun, Ji Ho; Lee, Jung Eun; Lee, Hee Ju; Nho, Chu Won; Bae, Gwi- Nam; Jung, Jae Hee

2015-01-01

Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2filter at 3-, 6-, and 9-min depositions, respectively). In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97%) than for M. luteus aerosols (~95%). High-performance liquid chromatography (HPLC) and electrospray ionization-tandem mass spectrometry (ESI/MS) analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß)-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a bioaerosol control system that is environmental friendly and suitable for use in indoor environments. PMID:25974109

Preparation of metallic nanoparticles by irradiation in starch aqueous solution

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

Nemţanu, Monica R., E-mail: monica.nemtanu@inflpr.ro; Braşoveanu, Mirela, E-mail: monica.nemtanu@inflpr.ro; Iacob, Nicuşor, E-mail: monica.nemtanu@inflpr.ro

Colloidal silver nanoparticles (AgNPs) were synthesized in a single step by electron beam irradiation reduction of silver ions in aqueous solution containing starch. The nanoparticles were characterized by spectrophotocolorimetry and compared with those obtained by chemical (thermal) reduction method. The results showed that the smaller sizes of AgNPs were prepared with higher yields as the irradiation dose increased. The broadening of particle size distribution occurred by increasing of irradiation dose and dose rate. Chromatic parameters such as b* (yellow-blue coordinate), C* (chroma) and ΔE{sub ab} (total color difference) could characterize the nanoparticles with respect of their concentration. Hue angle h{supmore » o} was correlated to the particle size distribution. Experimental data of the irradiated samples were also subjected to factor analysis using principal component extraction and varimax rotation in order to reveal the relation between dependent variables and independent variables and to reduce their number. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those produced by chemical reduction method. Therefore, the electron beam irradiation is effective for preparation of silver nanoparticles using starch aqueous solution as dispersion medium.« less

Genetically engineered and self-assembled oncolytic protein nanoparticles for targeted cancer therapy.

PubMed

Lee, Joong-Jae; Kang, Jung Ae; Ryu, Yiseul; Han, Sang-Soo; Nam, You Ree; Rho, Jong Kook; Choi, Dae Seong; Kang, Sun-Woong; Lee, Dong-Eun; Kim, Hak-Sung

2017-03-01

The integration of a targeted delivery with a tumour-selective agent has been considered an ideal platform for achieving high therapeutic efficacy and negligible side effects in cancer therapy. Here, we present engineered protein nanoparticles comprising a tumour-selective oncolytic protein and a targeting moiety as a new format for the targeted cancer therapy. Apoptin from chicken anaemia virus (CAV) was used as a tumour-selective apoptotic protein. An EGFR-specific repebody, which is composed of LRR (Leucine-rich repeat) modules, was employed to play a dual role as a tumour-targeting moiety and a fusion partner for producing apoptin nanoparticles in E. coli, respectively. The repebody was genetically fused to apoptin, and the resulting fusion protein was shown to self-assemble into supramolecular repebody-apoptin nanoparticles with high homogeneity and stability as a soluble form when expressed in E. coli. The repebody-apoptin nanoparticles showed a remarkable anti-tumour activity with negligible side effects in xenograft mice through a cooperative action of the two protein components with distinct functional roles. The repebody-apoptin nanoparticles can be developed as a systemic injectable and tumour-selective therapeutic protein for targeted cancer treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted with mixed hollow sphere template method

NASA Astrophysics Data System (ADS)

Gopi, D.; Indira, J.; Kavitha, L.; Sekar, M.; Mudali, U. Kamachi

Hydroxyapatite (HAP) is the main inorganic component of bone material and is widely used in various biomedical applications due to its excellent bioactivity and biocompatibility. In this paper, we have reported the synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted mixed template directed method. In this method glycine-acrylic acid (GLY-AA) hollow spheres were used as an organic template which could be prepared by mixing of glycine with acrylic acid. The as-synthesized HAP nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and tunnelling electron microscope (TEM) to investigate the nature of bonding, crystallinity, size and shape. The thermal stability of as-synthesized nanoparticles was also investigated by the thermo gravimetric analysis (TGA). The effect of ultrasonic irradiation time on the crystallinity and size of the HAP nanoparticles in presence of glycine-acrylic acid hollow spheres template were investigated. From the inspection of the above results it is confirmed that the crystallinity and size of the HAP nanoparticles decrease with increasing ultrasonic irradiation time. Hence the proposed synthesis strategy provides a facile pathway to obtain nano sized HAP with high quality, suitable size and morphology.

Size effect on the magnetic properties of antiferromagnetic La0.2Ca0.8MnO3 nanoparticles

NASA Astrophysics Data System (ADS)

Markovich, V.; Fita, I.; Wisniewski, A.; Mogilyansky, D.; Puzniak, R.; Titelman, L.; Martin, C.; Gorodetsky, G.

2010-03-01

Magnetic properties of electron-doped La0.2Ca0.8MnO3 manganite nanoparticles with average particle size ranging from 15 to 37 nm, prepared by the glycine-nitrate method, have been investigated in temperature range 5-300 K and in magnetic fields up to 90 kOe. A monotonous enhancement of weak ferromagnetism linked to the reduction in the particle size was observed for all nanoparticles. Magnetic hysteresis loops also indicate size-dependent exchange bias effect displayed by horizontal and vertical shifts in field-cooled processes. The magnetization data reveal two ferromagnetic components: first one appears at T˜200K and may be attributed to surface magnetization and second one appears as a result of spin canting of antiferromagnetic core or is developed at some interfaces inside nanoparticles. Time evolution of magnetization recorded in magnetic fields after the field cooling to low temperatures exhibits a very noisy behavior that may be caused by formation of collective state of nanoparticles with no clear tendency to reach equilibrium state. Magnetic properties of the nanoparticle samples are compared with those of the bulk La0.2Ca0.8MnO3 .

Synthesis and characterization of bracelet-like magnetic nanorings consisting of Ag-Fe3O4 bi-component nanoparticles.

PubMed

Zhou, Shuai; Chen, Qianwang

2011-09-14

Stable bracelet-like magnetic nanorings, formed by Ag-Fe(3)O(4) nanoparticles with an average size around 40 nm, have been successfully prepared in large scale by means of reducing Ag(+) and Fe(3+) simultaneously under mild conditions. In the reaction, tiny grains of silver are used as seeds to prompt small Fe(3)O(4) nanoparticles to grow larger, which is essential to enhance the magnetic dipole-dipole interactions, while only superparamagnetic Fe(3)O(4) nanoparticles (about 10 nm in size) can be obtained in the absence of Ag seeds. The XRD, TEM, SAED and the EDS line scan data reveal that these nanoparticles are in the core-shell structure. These magnetic Ag-Fe(3)O(4) nanoparticles assembled into nanorings by magnetic dipole-dipole interactions with a diameter of 100-200 nm. The saturation magnetization of the nanorings is 39.5 emu g(-1) at room temperature. The MRI images indicate that these kind of nanorings have the potential application in diagnostics as a T(2) MRI contrast agent. This journal is © The Royal Society of Chemistry 2011

Redox-mediated dissolution of paramagnetic nanolids to achieve a smart theranostic system

NASA Astrophysics Data System (ADS)

Wang, Aifei; Guo, Mingyi; Wang, Nan; Zhao, Jianyun; Qi, Wenxiu; Muhammad, Faheem; Chen, Liang; Guo, Yingjie; Nguyen, Nam-Trung; Zhu, Guangshan

2014-04-01

Manganese oxide (Mn3O4) nanoparticles have recently emerged as a promising T1 contrast agent. In this study, for the first time, we demonstrated an interaction of Mn3O4 with a biological system, and found redox sensitive behavior of these paramagnetic nanoparticles in intracellular reducing environment. Inspired by these findings, we for the first time used this interaction for some therapeutic advantages and designed a versatile mesoporous silica based nanotheranostic system to realize redox-activated enhanced magnetic resonance imaging and responsive anticancer drug delivery. Contrary to previous reports, we firstly prepared high quality amine terminated hydrophilic Mn3O4 nanolids, without using multistep ligand exchange strategies. The resulting water stable and small-sized Mn3O4 nanolids were subsequently used as nanolids to cap drug loaded nanochannels of a porous carrier. Exposure to highly prevalent intracellular reducing environment resulted in the steady-state dissolution of these nanolids and attained an intelligent drug release. Furthermore, the redox receptive dissolution of paramagnetic Mn3O4 nanolids into Mn2+ in turn increases the T1 signal to twofold, providing an added opportunity to even track the feedback of therapy. This study, in addition to simultaneously realizing drug delivery and imaging, also provides a new insight into the fate and interaction of manganese oxide nanoparticles with components of biological systems.Manganese oxide (Mn3O4) nanoparticles have recently emerged as a promising T1 contrast agent. In this study, for the first time, we demonstrated an interaction of Mn3O4 with a biological system, and found redox sensitive behavior of these paramagnetic nanoparticles in intracellular reducing environment. Inspired by these findings, we for the first time used this interaction for some therapeutic advantages and designed a versatile mesoporous silica based nanotheranostic system to realize redox-activated enhanced magnetic resonance imaging and responsive anticancer drug delivery. Contrary to previous reports, we firstly prepared high quality amine terminated hydrophilic Mn3O4 nanolids, without using multistep ligand exchange strategies. The resulting water stable and small-sized Mn3O4 nanolids were subsequently used as nanolids to cap drug loaded nanochannels of a porous carrier. Exposure to highly prevalent intracellular reducing environment resulted in the steady-state dissolution of these nanolids and attained an intelligent drug release. Furthermore, the redox receptive dissolution of paramagnetic Mn3O4 nanolids into Mn2+ in turn increases the T1 signal to twofold, providing an added opportunity to even track the feedback of therapy. This study, in addition to simultaneously realizing drug delivery and imaging, also provides a new insight into the fate and interaction of manganese oxide nanoparticles with components of biological systems. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05687b

Production of solid lipid nanoparticles (SLN): scaling up feasibilities.

PubMed

Dingler, A; Gohla, S

2002-01-01

Solid lipid nanoparticles (SLN/Lipopearls) are widely discussed as a new colloidal drug carrier system. In contrast to polymeric systems, such as Polylactic copolyol microcapsules, these systems show with a good biocompatibility, if applied parenterally. The solid lipid matrices can be comprised of fats or waxes, and allow protection of incorporated active ingredients against chemical and physical degradation. The SLN can either be produced by 'hot homogenization' of melted lipids at elevated temperatures or by a 'cold homogenization' process. This paper deals with production technologies for SLN formulations, based on non-ethoxylated fat components for topical application and high pressure homogenization. Based on the chosen fat components, a novel and easy manufacturing and scaling-up method was developed to maintain chemical and physical integrity of the encapsulated active ingredients in the carrier.

One-pot synthesis of LaFeO3-NiFe2O4 nanocomposite ceramic by egg-white method and its magnetic and dielectric properties

NASA Astrophysics Data System (ADS)

Muthu, K. Sudalai; Lakshminarasimhan, N.; Perumal, P.

2017-10-01

A facile, one-pot synthesis of nanocomposite of LaFeO3-NiFe2O4 was demonstrated by using egg-white method. The same method was adopted to synthesize the individual component oxide nanoparticles of LaFeO3 (LFO) and NiFe2O4 (NFO). The phase formation of individual components and the nanocomposite was confirmed using powder X-Ray diffraction (XRD) technique. The measured room temperature magnetic properties of LFO, NFO and LFO-NFO nanoparticles revealed an enhancement in the properties of the nanocomposite. The dielectric behaviours of LFO, NFO and LFO-NFO pellets sintered at different temperatures such as 800, 900 and 1000 °C were investigated and correlated with the microstructures.

The influence of mannitol on morphology and disintegration of spray-dried nano-embedded microparticles.

PubMed

Torge, Afra; Grützmacher, Philipp; Mücklich, Frank; Schneider, Marc

2017-06-15

Nano-embedded microparticles represent a promising approach to deliver nanoparticles to the lungs. Microparticles with an appropriate aerodynamic diameter enable an application by dry powder inhaler and the transport of nanoparticles into the airways. By disintegration after deposition, nanoparticles can be released to exhibit their advantages such as a sustained drug release and delivery of the drug across the mucus barrier. The use of an appropriate matrix excipient to embed the nanoparticles is essential for the necessary disintegration and release of nanoparticles. In this context we investigated the influence of mannitol on the morphology, aerodynamic properties and disintegration behavior of nano-embedded microparticles. PLGA nanoparticles and mannitol were spray dried each as sole component and in combination in three different ratios. An influence of the mannitol content on the morphology was observed. Pure mannitol microparticles were solid and spherical, while the addition of nanoparticles resulted in raisin-shaped hollow particles. The different morphologies can be explained by diffusion processes of the compounds described by the Péclet-number. All powders showed suitable aerodynamic properties. By dispersion of the powders in simulated lung fluid, initial nanoparticle sizes could be recovered for samples containing mannitol. The fraction of redispersed nanoparticles was increased with increasing mannitol content. To evaluate the disintegration under conditions with higher comparability to the in vivo situation, spray-dried powders were exposed to >90% relative humidity. The disintegration behavior was monitored by analyzing roughness values by white light interferometry and supporting SEM imaging. The exposure to high relative humidity was shown to be sufficient for disintegration of the microparticles containing mannitol, releasing morphologically unchanged nanoparticles. With increasing mannitol content, the disintegration occurred faster and to a higher degree. Under these conditions, microparticles only composed of nanoparticles did not disintegrate. By enabling the release of nanoparticles from nano-embedded microparticles, mannitol was shown to be an ideal excipient to convert nanoparticles by spray drying into an inhalable dry power formulation. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced Immunomodulatory Activity of Gelatin-Encapsulated Rubus coreanus Miquel Nanoparticles

PubMed Central

Seo, Yong Chang; Choi, Woon Yong; Lee, Choon Geun; Cha, Seon Woo; Kim, Young Ock; Kim, Jin-Chul; Drummen, Gregor P. C.; Lee, Hyeon Yong

2011-01-01

The aim of this work was to investigate the immunomodulatory activities of Rubus coreanus Miquel extract-loaded gelatin nanoparticles. The mean size of the produced nanoparticles was 143 ± 18 nm with a bandwidth of 76 nm in the size distribution and a maximum size of ~200 nm, which allows effective nanoparticle uptake by cells. Confocal imaging confirmed this, since the nanoparticles were internalized within 30 min and heterogeneously distributed throughout the cell. Zeta-potential measurements showed that from pH = 5 onwards, the nanoparticles were highly negatively charged, which prevents agglomeration to clusters by electrostatic repulsion. This was confirmed by TEM imaging, which showed a well dispersed colloidal solution. The encapsulation efficiency was nearly 60%, which is higher than for other components encapsulated in gelatin nanoparticles. Measurements of immune modulation in immune cells showed a significant effect by the crude extract, which was only topped by the nanoparticles containing the extract. Proliferation of B-, T- and NK cells was notably enhanced by Rubus coreanus-gelatin nanoparticles and in general ~2–3 times higher than control and on average ~2 times higher than ferulic acid. R. coreanus-gelatin nanoparticles induced cytokine secretion (IL-6 and TNF-α) from B- and T-cells on average at a ~2–3 times higher rate compared with the extract and ferulic acid. In vivo immunomodulatory activity in mice fed with R. coreanus-gelatin nanoparticles at 1 mL/g body weight showed a ~5 times higher antibody production compared to control, a ~1.3 times higher production compared to the extract only, and a ~1.6 times higher production compared to ferulic acid. Overall, our results suggest that gelatin nanoparticles represent an excellent transport vehicle for Rubus coreanus extract and extracts from other plants generally used in traditional Asian medicine. Such nanoparticles ensure a high local concentration that results in enhancement of immune cell activities, including proliferation, cytokine secretion, and antibody production. PMID:22272118

The functional dissection of the plasma corona of SiO₂-NPs spots histidine rich glycoprotein as a major player able to hamper nanoparticle capture by macrophages.

PubMed

Fedeli, Chiara; Segat, Daniela; Tavano, Regina; Bubacco, Luigi; De Franceschi, Giorgia; de Laureto, Patrizia Polverino; Lubian, Elisa; Selvestrel, Francesco; Mancin, Fabrizio; Papini, Emanuele

2015-11-14

A coat of strongly-bound host proteins, or hard corona, may influence the biological and pharmacological features of nanotheranostics by altering their cell-interaction selectivity and macrophage clearance. With the goal of identifying specific corona-effectors, we investigated how the capture of amorphous silica nanoparticles (SiO2-NPs; Ø = 26 nm; zeta potential = -18.3 mV) by human lymphocytes, monocytes and macrophages is modulated by the prominent proteins of their plasma corona. LC MS/MS analysis, western blotting and quantitative SDS-PAGE densitometry show that Histidine Rich Glycoprotein (HRG) is the most abundant component of the SiO2-NP hard corona in excess plasma from humans (HP) and mice (MP), together with minor amounts of the homologous Kininogen-1 (Kin-1), while it is remarkably absent in their Foetal Calf Serum (FCS)-derived corona. HRG binds with high affinity to SiO2-NPs (HRG Kd ∼2 nM) and competes with other plasma proteins for the NP surface, so forming a stable and quite homogeneous corona inhibiting nanoparticles binding to the macrophage membrane and their subsequent uptake. Conversely, in the case of lymphocytes and monocytes not only HRG but also several common plasma proteins can interchange in this inhibitory activity. The depletion of HRG and Kin-1 from HP or their plasma exhaustion by increasing NP concentration (>40 μg ml(-1) in 10% HP) lead to a heterogeneous hard corona, mostly formed by fibrinogen (Fibr), HDLs, LDLs, IgGs, Kallikrein and several minor components, allowing nanoparticle binding to macrophages. Consistently, the FCS-derived SiO2-NP hard corona, mainly formed by hemoglobin, α2 macroglobulin and HDLs but lacking HRG, permits nanoparticle uptake by macrophages. Moreover, purified HRG competes with FCS proteins for the NP surface, inhibiting their recruitment in the corona and blocking NP macrophage capture. HRG, the main component of the plasma-derived SiO2-NPs' hard corona, has antiopsonin characteristics and uniquely confers to these particles the ability to evade macrophage capture.

Facile synthesis of silver nanoparticles and its antibacterial activity against Escherichia coli and unknown bacteria on mobile phone touch surfaces/computer keyboards

NASA Astrophysics Data System (ADS)

Reddy, T. Ranjeth Kumar; Kim, Hyun-Joong

2016-07-01

In recent years, there has been significant interest in the development of novel metallic nanoparticles using various top-down and bottom-up synthesis techniques. Kenaf is a huge biomass product and a potential component for industrial applications. In this work, we investigated the green synthesis of silver nanoparticles (AgNPs) by using kenaf ( Hibiscus cannabinus) cellulose extract and sucrose, which act as stabilizing and reducing agents in solution. With this method, by changing the pH of the solution as a function of time, we studied the optical, morphological and antibacterial properties of the synthesized AgNPs. In addition, these nanoparticles were characterized by Ultraviolet-visible spectroscopy, transmission electron microscopy (TEM), field-emission scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy and energy-dispersive X-ray spectroscopy (EDX). As the pH of the solution varies, the surface plasmon resonance peak also varies. A fast rate of reaction at pH 10 compared with that at pH 5 was identified. TEM micrographs confirm that the shapes of the particles are spherical and polygonal. Furthermore, the average size of the nanoparticles synthesized at pH 5, pH 8 and pH 10 is 40.26, 28.57 and 24.57 nm, respectively. The structure of the synthesized AgNPs was identified as face-centered cubic (fcc) by XRD. The compositional analysis was determined by EDX. FTIR confirms that the kenaf cellulose extract and sucrose act as stabilizing and reducing agents for the silver nanoparticles. Meanwhile, these AgNPs exhibited size-dependent antibacterial activity against Escherichia coli ( E. coli) and two other unknown bacteria from mobile phone screens and computer keyboard surfaces.

Ordering of anisotropic nanoparticles in diblock copolymer lamellae: Simulations with dissipative particle dynamics and a molecular theory.

PubMed

Berezkin, Anatoly V; Kudryavtsev, Yaroslav V; Gorkunov, Maxim V; Osipov, Mikhail A

2017-04-14

Local distribution and orientation of anisotropic nanoparticles in microphase-separated symmetric diblock copolymers has been simulated using dissipative particle dynamics and analyzed with a molecular theory. It has been demonstrated that nanoparticles are characterized by a non-trivial orientational ordering in the lamellar phase due to their anisotropic interactions with isotropic monomer units. In the simulations, the maximum concentration and degree of ordering are attained for non-selective nanorods near the domain boundary. In this case, the nanorods have a certain tendency to align parallel to the interface in the boundary region and perpendicular to it inside the domains. Similar orientation ordering of nanoparticles located at the lamellar interface is predicted by the molecular theory which takes into account that the nanoparticles interact with monomer units via both isotropic and anisotropic potentials. Computer simulations enable one to study the effects of the nanorod concentration, length, stiffness, and selectivity of their interactions with the copolymer components on the phase stability and orientational order of nanoparticles. If the volume fraction of the nanorods is lower than 0.1, they have no effect on the copolymer transition from the disordered state into a lamellar microstructure. Increasing nanorod concentration or nanorod length results in clustering of the nanorods and eventually leads to a macrophase separation, whereas the copolymer preserves its lamellar morphology. Segregated nanorods of length close to the width of the diblock copolymer domains are stacked side by side into smectic layers that fill the domain space. Thus, spontaneous organization and orientation of nanorods leads to a spatial modulation of anisotropic composite properties which may be important for various applications.

Ordering of anisotropic nanoparticles in diblock copolymer lamellae: Simulations with dissipative particle dynamics and a molecular theory

NASA Astrophysics Data System (ADS)

Berezkin, Anatoly V.; Kudryavtsev, Yaroslav V.; Gorkunov, Maxim V.; Osipov, Mikhail A.

2017-04-01

Local distribution and orientation of anisotropic nanoparticles in microphase-separated symmetric diblock copolymers has been simulated using dissipative particle dynamics and analyzed with a molecular theory. It has been demonstrated that nanoparticles are characterized by a non-trivial orientational ordering in the lamellar phase due to their anisotropic interactions with isotropic monomer units. In the simulations, the maximum concentration and degree of ordering are attained for non-selective nanorods near the domain boundary. In this case, the nanorods have a certain tendency to align parallel to the interface in the boundary region and perpendicular to it inside the domains. Similar orientation ordering of nanoparticles located at the lamellar interface is predicted by the molecular theory which takes into account that the nanoparticles interact with monomer units via both isotropic and anisotropic potentials. Computer simulations enable one to study the effects of the nanorod concentration, length, stiffness, and selectivity of their interactions with the copolymer components on the phase stability and orientational order of nanoparticles. If the volume fraction of the nanorods is lower than 0.1, they have no effect on the copolymer transition from the disordered state into a lamellar microstructure. Increasing nanorod concentration or nanorod length results in clustering of the nanorods and eventually leads to a macrophase separation, whereas the copolymer preserves its lamellar morphology. Segregated nanorods of length close to the width of the diblock copolymer domains are stacked side by side into smectic layers that fill the domain space. Thus, spontaneous organization and orientation of nanorods leads to a spatial modulation of anisotropic composite properties which may be important for various applications.

Surface-enhanced Raman scattering active gold nanoparticle/nanohole arrays fabricated through electron beam lithography

NASA Astrophysics Data System (ADS)

Wu, Tsunghsueh; Lin, Yang-Wei

2018-03-01

Effective surface-enhanced Raman scattering (SERS)-active substrates from gold nanoparticle and gold nanohole arrays were successfully fabricated through electron beam lithography with precise computer-aided control of the unit size and intergap distance. Their SERS performance was evaluated using 4-mercaptobenzoic acid (4-MBA). These gold arrays yielded strong SERS signals under 785 nm laser excitation. The enhancement factors for 4-MBA molecules on the prepared gold nanoparticle and nanohole arrays maxed at 1.08 × 107 and 8.61 × 106, respectively. The observed increase in SERS enhancement was attributed to the localized surface plasmon resonance (LSPR) wavelength shifting toward the near-infrared regime when the gold nanohole diameter increased, in agreement with the theoretical prediction in this study. The contribution of LSPR to the Raman enhancement from nanohole arrays deposited on fluorine-doped tin oxide glass was elucidated by comparing SERS and transmission spectra. This simple fabrication procedure, which entails employing electron beam lithography and the controllability of the intergap distance, suggests highly promising uses of nanohole arrays as functional components in sensing and photonic devices.

Synthesis, characteristics and thermoluminescent dosimetry features of γ-irradiated Ce doped CaF2 nanophosphor.

PubMed

Zahedifar, M; Sadeghi, E; Mozdianfard, M R; Habibi, E

2013-08-01

Nanoparticles of cerium doped calcium fluoride (CaF2:Ce) were synthesized for the first time using the hydrothermal method. The formation of nanostructures was confirmed by X-ray diffraction (XRD) patterns, indicating cubic lattice structure for the particles produced. Their shape and size were observed by scanning electron microscopy (SEM). Thermoluminescence characteristics were studied by having the samples irradiated by gamma rays of (60)Co source. The optimum thermal treatment of 400 °C for 30 min was found for the produced nanoparticles. The Tm-Tstop and computerized glow curve deconvolution (CGCD) methods, used to determine the number of component glow peaks and kinetic parameters, indicated seven overlapping glow peaks on the TL glow curve at approximately 394, 411, 425, 445, 556, 594 and 632 K. A linear dose response of up to 2000 Gy, was observed for the prepared nanoparticles. Maximum TL sensitivity was found at 0.4 mol% of Ce impurity. Other TL dosimetry features, including reusability and fading, were also presented and discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Investigation of cloud point extraction for the analysis of metallic nanoparticles in a soil matrix

PubMed Central

Hadri, Hind El; Hackley, Vincent A.

2017-01-01

The characterization of manufactured nanoparticles (MNPs) in environmental samples is necessary to assess their behavior, fate and potential toxicity. Several techniques are available, but the limit of detection (LOD) is often too high for environmentally relevant concentrations. Therefore, pre-concentration of MNPs is an important component in the sample preparation step, in order to apply analytical tools with a LOD higher than the ng kg−1 level. The objective of this study was to explore cloud point extraction (CPE) as a viable method to pre-concentrate gold nanoparticles (AuNPs), as a model MNP, spiked into a soil extract matrix. To that end, different extraction conditions and surface coatings were evaluated in a simple matrix. The CPE method was then applied to soil extract samples spiked with AuNPs. Total gold, determined by inductively coupled plasma mass spectrometry (ICP-MS) following acid digestion, yielded a recovery greater than 90 %. The first known application of single particle ICP-MS and asymmetric flow field-flow fractionation to evaluate the preservation of the AuNP physical state following CPE extraction is demonstrated. PMID:28507763

Novel strategy for synthesis of magnetic dummy molecularly imprinted nanoparticles based on functionalized silica as an efficient sorbent for the determination of acrylamide in potato chips: Optimization by experimental design methodology.

PubMed

Arabi, Maryam; Ostovan, Abbas; Ghaedi, Mehrorang; Purkait, Mihir K

2016-07-01

This study discusses a novel and simple method for the preparation of magnetic dummy molecularly imprinted nanoparticles (MDMINPs). Firstly, Fe3O4 magnetic nanoparticles (MNPs) were synthesized as a magnetic component. Subsequently, MDMINPs were constructed via the sol-gel strategy using APTMS as the functional monomer. Urethane was considered as dummy template to avoid residual template and TEOS as the cross linker. The prepared MDMINPs were used for the pre-concentration of acrylamide from potato chips. Quantification was carried out by high performance liquid chromatography with UV detection (HPLC-UV). The impact of influential variables such as pH, amount of sorbent, sonication time and eluent volume were well investigated and optimized using a central composite design. The particles had excellent magnetic property and high selectivity to the targeted molecule. In optimized conditions, the recovery ranged from 94.0% to 98.0% with the detection limit of 0.35µgkg(-1). Copyright © 2016 Elsevier B.V. All rights reserved.

Pb-free electronics: from nanotechnology to combinatorial materials science

NASA Astrophysics Data System (ADS)

Diaz Gonzalez, Alfredo J.

The elimination of lead (Pb) from the electronics industry due to a government directive caused problems on the manufacturing and use of electronic components. The current alloys used to attach components have a significant higher processing temperature (~30-40°C) that those containing Pb. The higher processing temperatures cause damage to the electronic components; printed circuit boards (PCB) and represents an increase in energetic costs for the manufacurer. Tin whiskers are out-of-plane structures that grow from tin (Sn) plated surfaces and cause short circuits and metal vapor arc. The electrical connection of components to the PCB relies on leads that are close to each other and are manufactured from tin-plated copper. Materials have shown a tendency to modify their bulk properties depending on powder particle size. Nanoparticle's coalescence temperature tends to decrease as particle size decreases. Exploiting this behavior, a nanoparticle based solder paste has been developed for attaching electronic components at a lower processing temperature to avoid thermally induced damage and reduce energy consumption. Tin nanoparticles were successfully synthesized via a wet chemistry route using tin (II) chloride dihydrated (metal precursor), 1,10-Phenanthroline (surfactant), and sodium borohydride (reducing agent). A flux system was developed based on Ethylene Glycol. Results showed acceptable coalescence of the non-capped nanoparticles at temperatures as low as 200°C with a processing time of 20 minutes. Synthesized nanoparticles with capping agent required higher flux content thus resulting in a poor metallic load paste. A reduction in processing temperature of approximately 40°C have been found when comparing the developed solder paste with typical SAC lead-free solders (~240°C). The electrical behavior was found to be an order of magnitude below that of bulk tin. Compositional libraries have been developed in an attempt to screen, via a high through-put method, alloys that are prone to tin whiskers growth. These libraries are samples containing a range of sub-samples with varying compositions within it than can be processed simultaneously. Using sputtering, a physical vapor deposition technique, a gradient composed of Ag-Cu was deposited over a Sn-plated Cu substrate. After reflow, the growth mechanism of the whiskers was accelerated using the IEC60068-82-2 standard. SEM and EDS analysis was used to charac-terize the growth of the tin whiskers at different elemental compositions. The gradients found across the samples are in accordance with the theoretical geometrical spacing. Tin whiskers were found on control samples, whereas almost all elemental compositions showed mitigation or elimination of the whiskers. This combinatorial material science methodology proved to be an efficient and fast screening method for the plating materials selection process in Pb-free electronics.

Cinnamomum casia Extract Encapsulated Nanochitosan as Antihypercholesterol

NASA Astrophysics Data System (ADS)

Ngadiwiyana; Purbowatiningrum; Fachriyah, Enny; Ismiyarto

2017-02-01

Atherosclerosis vascular disease with clinical manifestations such as cardiovascular disease and stroke are the leading cause of death in Indonesia. One solution to these problems is a natural antihypercholesterol medicine by utilizing Cinnamomum casia extract. However, the use of natural extracts to lower blood cholesterol levels do not provide optimal results because it is possible that the active components of extract have been degraded/damaged during the absorption process. So that, we need to do the research to get a combination of chitosan nanoparticles-Cinnamomum casia. extract as a compound which has an antihypercholesterol activity through the in vitro study. Modification of natural extracts encapsulated nanochitosan be a freshness in this study, which were conducted using the method of inclusion. The combination of both has the dual function of protecting the natural extracts from degradation and deliver the natural extracts to the target site. Analysis of nanochitosan using the Particle Size Analyzer (PSA) shows the particle size of synthesis product that is equal to 64.9 nm. Encapsulation efficiency of Cinnamomum casia extract-Chitosan Nanoparticles known through UV-VIS spectrophotometry test and obtained the efficiency encapsulation percentage of 84.93%. Zeta Potential at 193,3 mv that chitosan appropriate for a delivery drug. Antihypercholesterol activity tested in vitro assay that showed the extract-nanoparticle chitosan in concentration 150 ppm gave the highest cholesterol decreasing level in the amount of 49.66% w/v. So it can be concluded that Cinnamomum casia extract can be encapsulated in nanoparticles of chitosan and proved that it has a cholesterol-lowering effect through the in vitro study.

Workplace exposure to nanoparticles and the application of provisional nanoreference values in times of uncertain risks

NASA Astrophysics Data System (ADS)

van Broekhuizen, Pieter; van Broekhuizen, Fleur; Cornelissen, Ralf; Reijnders, Lucas

2012-03-01

Nano reference values (NRVs) for occupational use of nanomaterials were tested as provisional substitute for Occupational Exposure Limits (OELs). NRVs can be used as provisional limit values until Health-Based OELs or derived no-effect levels (DNEL) become available. NRVs were defined for 8 h periods (time weighted average) and for short-term exposure periods (15 min-time weighted average). To assess the usefulness of these NRVs, airborne number concentrations of nanoparticles (NPs) in the workplace environment were measured during paint manufacturing, electroplating, light equipment manufacturing, non-reflective glass production, production of pigment concentrates and car refinishing. Activities monitored were handling of solid engineered NPs (ENP), abrasion, spraying and heating during occupational use of nanomaterials (containing ENPs) and machining nanosurfaces. The measured concentrations are often presumed to contain ENPs as well as process-generated NPs (PGNP). The PGNP are found to be a significant source for potential exposure and cannot be ignored in risk assessment. Levels of NPs identified in workplace air were up to several millions of nanoparticles/cm3. Conventional components in paint manufacturing like CaCO3 and talc may contain a substantial amount of nanosized particulates giving rise to airborne nanoparticle concentrations. It is argued that risk assessments carried out for e.g. paint manufacturing processes using conventional non-nano components should take into account potential nanoparticle emissions as well. The concentrations measured were compared with particle-based NRVs and with mass-based values that have also been proposed for workers protection. It is concluded that NRVs can be used for risk management for handling or processing of nanomaterials at workplaces provided that the scope of NRVs is not limited to ENPs only, but extended to the exposure to process-generated NPs as well.

Nanomedicine: nanoparticles, molecular biosensors, and targeted gene/drug delivery for combined single-cell diagnostics and therapeutics

NASA Astrophysics Data System (ADS)

Prow, Tarl W.; Salazar, Jose H.; Rose, William A.; Smith, Jacob N.; Reece, Lisa; Fontenot, Andrea A.; Wang, Nan A.; Lloyd, R. Stephen; Leary, James F.

2004-07-01

Next generation nanomedicine technologies are being developed to provide for continuous and linked molecular diagnostics and therapeutics. Research is being performed to develop "sentinel nanoparticles" which will seek out diseased (e.g. cancerous) cells, enter those living cells, and either perform repairs or induce those cells to die through apoptosis. These nanoparticles are envisioned as multifunctional "smart drug delivery systems". The nanosystems are being developed as multilayered nanoparticles (nanocrystals, nanocapsules) containing cell targeting molecules, intracellular re-targeting molecules, molecular biosensor molecules, and drugs/enzymes/gene therapy. These "nanomedicine systems" are being constructed to be autonomous, much like present-day vaccines, but will have sophisticated targeting, sensing, and feedback control systems-much more sophisticated than conventional antibody-based therapies. The fundamental concept of nanomedicine is to not to just kill all aberrant cells by surgery, radiation therapy, or chemotherapy. Rather it is to fix cells, when appropriate, one cell-at-a-time, to preserve and re-build organ systems. When cells should not be fixed, such as in cases where an improperly repaired cell might give rise to cancer cells, the nanomedical therapy would be to induce apoptosis in those cells to eliminate them without the damagin bystander effects of the inflammatory immune response system reacting to necrotic cells or those which have died from trauma or injury. The ultimate aim of nanomedicine is to combine diagnostics and therapeutics into "real-time medicine", using where possible in-vivo cytometry techniques for diagnostics and therapeutics. A number of individual components of these multi-component nanoparticles are already working in in-vitro and ex-vivo cell and tissue systems. Work has begun on construction of integrated nanomedical systems.

Catalyst-layer ionomer imaging of fuel cells

DOE PAGES

Guetaz, Laure; Lopez-Haro, M.; Escribano, S.; ...

2015-09-14

Investigation of membrane/electrode assembly (MEA) microstructure has become an essential step to optimize the MEA components and manufacturing processes or to study the MEA degradation. For these investigations, transmission electron microscopy (TEM) is a tool of choice as it provides direct imaging of the different components. TEM is then widely used for analyzing the catalyst nanoparticles and their carbon support. However, the ionomer inside the electrode is more difficult to be imaged. The difficulties come from the fact that the ionomer forms an ultrathin layer surrounding the carbon particles and in addition, these two components, having similar density, present nomore » difference in contrast. In this paper, we show how the recent progresses in TEM techniques as spherical aberration (Cs) corrected HRTEM, electron tomography and X-EDS elemental mapping provide new possibilities for imaging this ionomer network and consequently to study its degradation.« less

Self-assembled Lyotropic Liquid Crystalline Phase Behavior of Monoolein-Capric Acid-Phospholipid Nanoparticulate Systems.

PubMed

Zhai, Jiali; Tran, Nhiem; Sarkar, Sampa; Fong, Celesta; Mulet, Xavier; Drummond, Calum J

2017-03-14

We report here the lyotropic liquid crystalline phase behavior of two lipid nanoparticulate systems containing mixtures of monoolein, capric acid, and saturated diacyl phosphatidylcholines dispersed by the Pluronic F127 block copolymer. Synchrotron small-angle X-ray scattering (SAXS) was used to screen the phase behavior of a library of lipid nanoparticles in a high-throughput manner. It was found that adding capric acid and phosphatidylcholines had opposing effects on the spontaneous membrane curvature of the monoolein lipid layer and hence the internal mesophase of the final nanoparticles. By varying the relative concentration of the three lipid components, we were able to establish a library of nanoparticles with a wide range of mesophases including at least the inverse bicontinuous primitive and double diamond cubic phases, the inverse hexagonal phase, the fluid lamellar phase, and possibly other phases. Furthermore, the in vitro cytotoxicity assay showed that the endogenous phospholipid-containing nanoparticles were less toxic to cultured cell lines compared to monoolein-based counterparts, improving the potential of the nonlamellar lipid nanoparticles for biomedical applications.

Transparent Large Strain Thermoplastic Polyurethane Magneto-Active Nanocomposites

NASA Technical Reports Server (NTRS)

Yoonessi, Mitra; Carpen, Ileana; Peck, John; Sola, Francisco; Bail, Justin; Lerch, Bradley; Meador, Michael

2010-01-01

Smart adaptive materials are an important class of materials which can be used in space deployable structures, morphing wings, and structural air vehicle components where remote actuation can improve fuel efficiency. Adaptive materials can undergo deformation when exposed to external stimuli such as electric fields, thermal gradients, radiation (IR, UV, etc.), chemical and electrochemical actuation, and magnetic field. Large strain, controlled and repetitive actuation are important characteristics of smart adaptive materials. Polymer nanocomposites can be tailored as shape memory polymers and actuators. Magnetic actuation of polymer nanocomposites using a range of iron, iron cobalt, and iron manganese nanoparticles is presented. The iron-based nanoparticles were synthesized using the soft template (1) and Sun's (2) methods. The nanoparticles shape and size were examined using TEM. The crystalline structure and domain size were evaluated using WAXS. Surface modifications of the nanoparticles were performed to improve dispersion, and were characterized with IR and TGA. TPU nanocomposites exhibited actuation for approximately 2wt% nanoparticle loading in an applied magnetic field. Large deformation and fast recovery were observed. These nanocomposites represent a promising potential for new generation of smart materials.

Coherent Rayleigh-Brillouin scattering for in situ detection of nanoparticles and large molecules in gas and plasma

NASA Astrophysics Data System (ADS)

Gerakis, A.; Shneider, M. N.; Stratton, B. C.; Santra, B.; Car, R.; Raitses, Y.

2016-09-01

Laser-based diagnostics methods, such as Spontaneous and Coherent Rayleigh and Rayleigh-Brillouin scattering (SRBS and CRBS), can be used for in-situ detection and characterization of nanoparticle shape and size as well as their concentration in an inert gas atmosphere. We recently developed and tested this advanced diagnostic at PPPL. It was shown that the signal intensity of the CRBS signal depends on the gas-nanoparticle mixture composition, density and the polarizabilities of the mixture components. The measured results agree well with theoretical predictions of Refs. In this work, we report the application of this diagnostic to monitor nucleation and growth of nanoparticles in a carbon arc discharge. In support of these measurements, A time-dependent density functional theory was used to compute the frequency-dependent polarizabilities of various nanostructures in order to predict the corresponding Rayleigh scattering intensities as well as light depolarization. Preliminary results of measurements demonstrate that CRBS is capable to detect nanoparticles in volume. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

Assembly and microscopic characterization of DNA origami structures.

PubMed

Scheible, Max; Jungmann, Ralf; Simmel, Friedrich C

2012-01-01

DNA origami is a revolutionary method for the assembly of molecular nanostructures from DNA with precisely defined dimensions and with an unprecedented yield. This can be utilized to arrange nanoscale components such as proteins or nanoparticles into pre-defined patterns. For applications it will now be of interest to arrange such components into functional complexes and study their geometry-dependent interactions. While commonly DNA nanostructures are characterized by atomic force microscopy or electron microscopy, these techniques often lack the time-resolution to study dynamic processes. It is therefore of considerable interest to also apply fluorescence microscopic techniques to DNA nanostructures. Of particular importance here is the utilization of novel super-resolved microscopy methods that enable imaging beyond the classical diffraction limit.

Synthesis of composite nanoparticles using co-precipitation of a magnetic iron-oxide shell onto core nanoparticles

NASA Astrophysics Data System (ADS)

Primc, Darinka; Belec, Blaž; Makovec, Darko

2016-03-01

Composite nanoparticles can be synthesized by coating a shell made of one material onto core nanoparticles made of another material. Here we report on a novel method for coating a magnetic iron oxide onto the surface of core nanoparticles in an aqueous suspension. The method is based on the heterogeneous nucleation of an initial product of Fe3+/Fe2+ co-precipitation on the core nanoparticles. The close control of the supersaturation of the precipitating species required for an exclusively heterogeneous nucleation and the growth of the shell were achieved by immobilizing the reactive Fe3+ ions in a nitrate complex with urea ([Fe((CO(NH2)2)6](NO3)3) and by using solid Mg(OH)2 as the precipitating reagent. The slow thermal decomposition of the complex at 60 °C homogeneously releases the reactive Fe3+ ions into the suspension of the core nanoparticles. The key stage of the process is the thermal hydrolysis of the released Fe3+ ions prior to the addition of Mg(OH)2. The thermal hydrolysis results in the formation of γ-FeOOH, exclusively at the surfaces of the core nanoparticles. After the addition of the solid hydroxide Mg(OH)2, the pH increases and at pH 5.7 the Fe2+ precipitates and reacts with the γ-FeOOH to form magnetic iron oxide with a spinel structure (spinel ferrite) at the surfaces of the core nanoparticles. The proposed low-temperature method for the synthesis of composite nanoparticles is capable of forming well-defined interfaces between the two components, important for the coupling of the different properties. The procedure is environmentally friendly, inexpensive, and appropriate for scaling up to mass production.

Compositional tuning of epoxide-polyetheramine "click" reaction toward cytocompatible, cationic hydrogel particles with antimicrobial and DNA binding activities.

PubMed

Tang, Shuangcheng; Huang, Lu; Daniels-Mulholland, Robert J; Dlugosz, Elizabeth; Morin, Emily A; Lenaghan, Scott; He, Wei

2016-10-01

The "click" characteristics of nucleophilic opening of epoxide have recently been exploited for the development of a functional hydrogel particle system based on commercially available bisepoxide and triamine polyetheramine monomers. Key features of these particles include high cationic charges and responsiveness to temperature, pH, and oxidation. Despite these advantages, the cytocompatibility of these particles must be considered prior to use in biomedical applications. Here we demonstrate that, by introducing a diamine polyetheramine as a comonomer in the "click" reaction, and tuning its molar ratio with the triamine monomer, cationic nanoparticles with improved cytocompatibility can be prepared. The reduced cytotoxicity is primarily due to the hydrophilic backbone of the diamine comonomer, which has polyethylene glycol as a primary component. The resulting nanoparticles formed from the diamine comonomer exhibited a lower surface charge, while maintaining a comparable size. In addition, the responsiveness of the nanoparticles to temperature, pH, and oxidation was conserved, while achieving greater colloidal stability at basic pH. Results from this study further demonstrated that the nanoparticles were able to encapsulate Nile red, a model for hydrophobic drug molecules, were effective against the bacteria Staphylococcus aureus, and were capable of binding DNA through ionic complexation. Based on the results from this work, the use of diamine comonomers significantly reduces the cytotoxicity of similarly developed hydrogel nanoparticles, allowing for numerous biomedical applications, including nanocarriers for therapeutic agents with poor water solubility, treatment of bacterial infection, and non-viral vectors for gene therapy. In recent years significant attention has been placed on the development of nanocarriers for numerous biomedical applications. Of particular interest are cationic polymers, which contain high positive surface charges that allow binding of numerous therapeutic agents. Unfortunately, the advantages of cationic polymers for binding, are often negated by the tendency of these polymers to be cytotoxic. Previous studies have developed highly responsive cationic hydrogel nanoparticles, which meet several of the criteria for biomedical applications, but were acutely cytotoxic. In this work, cationic hydrogel nanoparticles, with significantly improved cytocompatibility, were synthesized using simple, green epoxy chemistry. In addition, the ability of these nanoparticles to maintain a small size (<500nm), bind DNA, encapsulate hydrophobic drugs, and kill bacteria was maintained. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

[Development of Inhalable Dry Powder Formulations Loaded with Nanoparticles Maintaining Their Original Physical Properties and Functions].

PubMed

Okuda, Tomoyuki

2017-01-01

 Functional nanoparticles, such as liposomes and polymeric micelles, are attractive drug delivery systems for solubilization, stabilization, sustained release, prolonged tissue retention, and tissue targeting of various encapsulated drugs. For their clinical application in therapy for pulmonary diseases, the development of dry powder inhalation (DPI) formulations is considered practical due to such advantages as: (1) it is noninvasive and can be directly delivered into the lungs; (2) there are few biocomponents in the lungs that interact with nanoparticles; and (3) it shows high storage stability in the solid state against aggregation or precipitation of nanoparticles in water. However, in order to produce effective nanoparticle-loaded dry powders for inhalation, it is essential to pursue an innovative and comprehensive formulation strategy in relation to composition and powderization which can achieve (1) the particle design of dry powders with physical properties suitable for pulmonary delivery through inhalation, and (2) the effective reconstitution of nanoparticles that will maintain their original physical properties and functions after dissolution of the powders. Spray-freeze drying (SFD) is a relatively new powderization technique combining atomization and lyophilization, which can easily produce highly porous dry powders from an aqueous sample solution. Previously, we advanced the optimization of components and process conditions for the production of SFD powders suitable to DPI application. This review describes our recent results in the development of novel DPI formulations effectively loaded with various nanoparticles (electrostatic nanocomplexes for gene therapy, liposomes, and self-assembled lipid nanoparticles), based on SFD.

On the design of composite protein-quantum dot biomaterials via self-assembly.

PubMed

Majithia, Ravish; Patterson, Jan; Bondos, Sarah E; Meissner, Kenith E

2011-10-10

Incorporation of nanoparticles during the hierarchical self-assembly of protein-based materials can impart function to the resulting composite materials. Herein we demonstrate that the structure and nanoparticle distribution of composite fibers are sensitive to the method of nanoparticle addition and the physicochemical properties of both the nanoparticle and the protein. Our model system consists of a recombinant enhanced green fluorescent protein-Ultrabithorax (EGFP-Ubx) fusion protein and luminescent CdSe-ZnS core-shell quantum dots (QDs), allowing us to optically assess the distribution of both the protein and nanoparticle components within the composite material. Although QDs favorably interact with EGFP-Ubx monomers, the relatively rough surface morphology of composite fibers suggests EGFP-Ubx-QD conjugates impact self-assembly. Indeed, QDs templated onto EGFP-Ubx film post-self-assembly can be subsequently drawn into smooth composite fibers. Additionally, the QD surface charge impacts QD distribution within the composite material, indicating that surface charge plays an important role in self-assembly. QDs with either positively or negatively charged coatings significantly enhance fiber extensibility. Conversely, QDs coated with hydrophobic moieties and suspended in toluene produce composite fibers with a heterogeneous distribution of QDs and severely altered fiber morphology, indicating that toluene severely disrupts Ubx self-assembly. Understanding factors that impact the protein-nanoparticle interaction enables manipulation of the structure and mechanical properties of composite materials. Since proteins interact with nanoparticle surface coatings, these results should be applicable to other types of nanoparticles with similar chemical groups on the surface.

DNA-programmable nanoparticle crystallization.

PubMed

Park, Sung Yong; Lytton-Jean, Abigail K R; Lee, Byeongdu; Weigand, Steven; Schatz, George C; Mirkin, Chad A

2008-01-31

It was first shown more than ten years ago that DNA oligonucleotides can be attached to gold nanoparticles rationally to direct the formation of larger assemblies. Since then, oligonucleotide-functionalized nanoparticles have been developed into powerful diagnostic tools for nucleic acids and proteins, and into intracellular probes and gene regulators. In contrast, the conceptually simple yet powerful idea that functionalized nanoparticles might serve as basic building blocks that can be rationally assembled through programmable base-pairing interactions into highly ordered macroscopic materials remains poorly developed. So far, the approach has mainly resulted in polymerization, with modest control over the placement of, the periodicity in, and the distance between particles within the assembled material. That is, most of the materials obtained thus far are best classified as amorphous polymers, although a few examples of colloidal crystal formation exist. Here, we demonstrate that DNA can be used to control the crystallization of nanoparticle-oligonucleotide conjugates to the extent that different DNA sequences guide the assembly of the same type of inorganic nanoparticle into different crystalline states. We show that the choice of DNA sequences attached to the nanoparticle building blocks, the DNA linking molecules and the absence or presence of a non-bonding single-base flexor can be adjusted so that gold nanoparticles assemble into micrometre-sized face-centred-cubic or body-centred-cubic crystal structures. Our findings thus clearly demonstrate that synthetically programmable colloidal crystallization is possible, and that a single-component system can be directed to form different structures.

Monitoring of magnetic nano-particles in EOR by using the CSEM modeling and inversion.

NASA Astrophysics Data System (ADS)

Heo, J. Y.; KIM, S.; Jeong, G.; Hwang, J.; Min, D. J.

2016-12-01

EOR, which injects water, CO2, or other chemical components into reservoirs to increase the production rate of oil and gas, has widely been used. To promote efficiency of EOR, it is important to monitor distribution of injected materials in reservoirs. Using nano-particles in EOR has advantages that the size of particles is smaller than the pore and particles can be characterized by various physical properties. Specifically, if we use magnetic nano-particles, we can effectively monitor nano-particles by using the electromagnetic survey. CSEM, which can control the frequency range of source, is good to monitor magnetic nano-particles under various reservoir circumstances. In this study, we first perform numerical simulation of 3D CSEM for reservoir under production. In general, two wells are used for EOR: one is for injection, and the other is for extraction. We assume that sources are applied inside the injection well, and receivers are deployed inside the extraction well. To simulate the CSEM survey, we decompose the total fields into primary and secondary fields in Maxwell's equations. For the primary fields, we calculate the analytic solutions of the layered earth. With the calculated primary fields, we compute the secondary fields due to anomalies using the edge-based finite-element method. Finally, we perform electromagnetic inversion for both conductivity and permeability to trace the distribution of magnetic nano-particles. Since these two parameters react differently according to the frequency range of sources, we can effectively describe the distribution of magnetic nano-particles by considering two parameters at the same time. Acknowledgements This work was supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP) and the Ministry of Trade, Industry & Energy(MOTIE) of the Republic of Korea (No. 20168510030830), and by the International Cooperation (No. 2012-8510030010) of KETEP, and by the Dual Use Technology Program, granted financial resource from the MOTIE.

Effect of intra-articular administration of superparamagnetic iron oxide nanoparticles (SPIONs) for MRI assessment of the cartilage barrier in a large animal model

PubMed Central

Hall, Sarah; Xia, Xin-Rui; Schwarz, Tobias

2017-01-01

Early diagnosis of cartilage disease at a time when changes are limited to depletion of extracellular matrix components represents an important diagnostic target to reduce patient morbidity. This report is to present proof of concept for nanoparticle dependent cartilage barrier imaging in a large animal model including the use of clinical magnetic resonance imaging (MRI). Conditioned (following matrix depletion) and unconditioned porcine metacarpophalangeal cartilage was evaluated on the basis of fluorophore conjugated 30 nm and 80 nm spherical gold nanoparticle permeation and multiphoton laser scanning and bright field microscopy after autometallographic particle enhancement. Consequently, conditioned and unconditioned joints underwent MRI pre- and post-injection with 12 nm superparamagnetic iron oxide nanoparticles (SPIONs) to evaluate particle permeation in the context of matrix depletion and use of a clinical 1.5 Tesla MRI scanner. To gauge the potential pro-inflammatory effect of intra-articular nanoparticle delivery co-cultures of equine synovium and cartilage tissue were exposed to an escalating dose of SPIONs and IL-6, IL-10, IFN-γ and PGE2 were assessed in culture media. The chemotactic potential of growth media samples was subsequently assessed in transwell migration assays on isolated equine neutrophils. Results demonstrate an increase in MRI signal following conditioning of porcine joints which suggests that nanoparticle dependent compositional cartilage imaging is feasible. Tissue culture and neutrophil migration assays highlight a dose dependent inflammatory response following SPION exposure which at the imaging dose investigated was not different from controls. The preliminary safety and imaging data support the continued investigation of nanoparticle dependent compositional cartilage imaging. To our knowledge, this is the first report in using SPIONs as intra-articular MRI contrast agent for studying cartilage barrier function, which could potentially lead to a new diagnostic technique for early detection of cartilage disease. PMID:29287105

Gold nanoparticles-based protease assay

PubMed Central

Guarise, Cristian; Pasquato, Lucia; De Filippis, Vincenzo; Scrimin, Paolo

2006-01-01

We describe here a simple assay that allows the visual detection of a protease. The method takes advantage of the high molar absorptivity of the plasmon band of gold colloids and is based on the color change of their solution when treated with dithiols. We used C- and N-terminal cysteinyl derivatives of a peptide substrate exploiting its selective recognition and cleavage by a specific protease. Contrary to the native ones, cleaved peptides are unable to induce nanoparticles aggregation; hence, the color of the solution does not change. The detection of two proteases is reported: thrombin (involved in blood coagulation and thrombosis) and lethal factor (an enzyme component of the toxin produced by Bacillus anthracis). The sensitivity of this nanoparticle-based assay is in the low nanomolar range. PMID:16537471

Self-assembled thin films of Fe3O4-Ag composite nanoparticles for spintronic applications

NASA Astrophysics Data System (ADS)

Jiang, Chengpeng; Leung, Chi Wah; Pong, Philip W. T.

2017-10-01

Controlled self-assembly of multi-component magnetic nanoparticles could lead to nanomaterial-based magnetic devices with novel structures and intriguing properties. Herein, self-assembled thin films of Fe3O4-Ag composite nanoparticles (CNPs) with hetero-dimeric shapes were fabricated using interfacial assembly method. The CNP-assembled thin films were further transferred to patterned silicon substrates followed by vacuum annealing, producing CNP-based magnetoresistive (MR) devices. Due to the presence of intra-particle interfaces and inter-particle barriers, an enhanced MR ratio and a non-linear current-voltage relation were observed in the device. The results of this work can potentially pave the way to the future exploration and development of spintronic devices built from composite nanomaterials.

Gold nanoparticles-based protease assay.

PubMed

Guarise, Cristian; Pasquato, Lucia; De Filippis, Vincenzo; Scrimin, Paolo

2006-03-14

We describe here a simple assay that allows the visual detection of a protease. The method takes advantage of the high molar absorptivity of the plasmon band of gold colloids and is based on the color change of their solution when treated with dithiols. We used C- and N-terminal cysteinyl derivatives of a peptide substrate exploiting its selective recognition and cleavage by a specific protease. Contrary to the native ones, cleaved peptides are unable to induce nanoparticles aggregation; hence, the color of the solution does not change. The detection of two proteases is reported: thrombin (involved in blood coagulation and thrombosis) and lethal factor (an enzyme component of the toxin produced by Bacillus anthracis). The sensitivity of this nanoparticle-based assay is in the low nanomolar range.

Cellular imaging using temporally flickering nanoparticles.

PubMed

Ilovitsh, Tali; Danan, Yossef; Meir, Rinat; Meiri, Amihai; Zalevsky, Zeev

2015-02-04

Utilizing the surface plasmon resonance effect in gold nanoparticles enables their use as contrast agents in a variety of applications for compound cellular imaging. However, most techniques suffer from poor signal to noise ratio (SNR) statistics due to high shot noise that is associated with low photon count in addition to high background noise. We demonstrate an effective way to improve the SNR, in particular when the inspected signal is indistinguishable in the given noisy environment. We excite the temporal flickering of the scattered light from gold nanoparticle that labels a biological sample. By preforming temporal spectral analysis of the received spatial image and by inspecting the proper spectral component corresponding to the modulation frequency, we separate the signal from the wide spread spectral noise (lock-in amplification).

Interaction with culture medium components, cellular uptake and intracellular distribution of cobalt nanoparticles, microparticles and ions in Balb/3T3 mouse fibroblasts.

PubMed

Sabbioni, Enrico; Fortaner, Salvador; Farina, Massimo; Del Torchio, Riccardo; Petrarca, Claudia; Bernardini, Giovanni; Mariani-Costantini, Renato; Perconti, Silvia; Di Giampaolo, Luca; Gornati, Rosalba; Di Gioacchino, Mario

2014-02-01

The mechanistic understanding of nanotoxicity requires the physico-chemical characterisation of nanoparticles (NP), and their comparative investigation relative to the corresponding ions and microparticles (MP). Following this approach, the authors studied the dissolution, interaction with medium components, bioavailability in culture medium, uptake and intracellular distribution of radiolabelled Co forms (CoNP, CoMP and Co(2+)) in Balb/3T3 mouse fibroblasts. Co(2+) first saturates the binding sites of molecules in the extracellular milieu (e.g., albumin and histidine) and on the cell surface. Only after saturation, Co(2+) is actively uptaken. CoNP, instead, are predicted to be internalised by endocytosis. Dissolution of Co particles allows the formation of Co compounds (CoNP-rel), whose mechanism of cellular internalisation is unknown. Co uptake (ranking CoMP > CoNP > Co(2+)) reached maximum at 4 h. Once inside the cell, CoNP spread into the cytosol and organelles. Consequently, massive amounts of Co ions and CoNP-rel can reach subcellular compartments normally unexposed to Co(2+). This could explain the fact that the nuclear and mitochondrial Co concentrations resulted significantly higher than those obtained with Co(2+).

Membrane mimetic surface functionalization of nanoparticles: Methods and applications

PubMed Central

Weingart, Jacob; Vabbilisetty, Pratima; Sun, Xue-Long

2013-01-01

Nanoparticles (NPs), due to their size-dependent physical and chemical properties, have shown remarkable potential for a wide range of applications over the past decades. Particularly, the biological compatibilities and functions of NPs have been extensively studied for expanding their potential in areas of biomedical application such as bioimaging, biosensing, and drug delivery. In doing so, surface functionalization of NPs by introducing synthetic ligands and/or natural biomolecules has become a critical component in regards to the overall performance of the NP system for its intended use. Among known examples of surface functionalization, the construction of an artificial cell membrane structure, based on phospholipids, has proven effective in enhancing biocompatibility and has become a viable alternative to more traditional modifications, such as direct polymer conjugation. Furthermore, certain bioactive molecules can be immobilized onto the surface of phospholipid platforms to generate displays more reminiscent of cellular surface components. Thus, NPs with membrane-mimetic displays have found use in a range of bioimaging, biosensing, and drug delivery applications. This review herein describes recent advances in the preparations and characterization of integrated functional NPs covered by artificial cell membrane structures and their use in various biomedical applications. PMID:23688632

Biodegradable Janus nanoparticles for local pulmonary delivery of hydrophilic and hydrophobic molecules to the lungs.

PubMed

Garbuzenko, Olga B; Winkler, Jennifer; Tomassone, M Silvina; Minko, Tamara

2014-11-04

The aim of the present work is to synthesize, characterize, and test self-assembled anisotropic or Janus particles designed to load anticancer drugs for lung cancer treatment by inhalation. The particles were synthesized using binary mixtures of biodegradable and biocompatible materials. The particles did not demonstrate cyto- and genotoxic effects. Janus particles were internalized by cancer cells and accumulated both in the cytoplasm and nuclei. After inhalation delivery, nanoparticles accumulated preferentially in the lungs of mice and retained there for at least 24 h. Two drugs or other biologically active components with substantially different aqueous solubility can be simultaneously loaded in two-phases (polymer-lipid) of these nanoparticles. In the present proof-of-concept investigation, the particles were loaded with two anticancer drugs: doxorubicin and curcumin as model anticancer drugs with relatively high and low aqueous solubility, respectively. However, there are no obstacles for loading any hydrophobic or hydrophilic chemical agents. Nanoparticles with dual load were used for their local inhalation delivery directly to the lungs of mice with orthotopic model of human lung cancer. In vivo experiments showed that the selected nanoparticles with two anticancer drugs with different mechanisms of action prevented progression of lung tumors. It should be stressed that anticancer effects of the combined treatment with two anticancer drugs loaded in the same nanoparticle significantly exceeded the effect of either drug loaded in similar nanoparticles alone.

Silica sol as grouting material: a physio-chemical analysis.

PubMed

Sögaard, Christian; Funehag, Johan; Abbas, Zareen

2018-01-01

At present there is a pressing need to find an environmentally friendly grouting material for the construction of tunnels. Silica nanoparticles hold great potential of replacing the organic molecule based grouting materials currently used for this purpose. Chemically, silica nanoparticles are similar to natural silicates which are essential components of rocks and soil. Moreover, suspensions of silica nanoparticles of different sizes and desired reactivity are commercially available. However, the use of silica nanoparticles as grouting material is at an early stage of its technological development. There are some critical parameters such as long term stability and functionality of grouted silica that need to be investigated in detail before silica nanoparticles can be considered as a reliable grouting material. In this review article we present the state of the art regarding the chemical properties of silica nanoparticles commercially available, as well as experience gained from the use of silica as grouting material. We give a detailed description of the mechanisms underlying the gelling of silica by different salt solutions such as NaCl and KCl and how factors such as particle size, pH, and temperature affect the gelling and gel strength development. Our focus in this review is on linking the chemical properties of silica nanoparticles to the mechanical properties to better understand their functionality and stability as grouting material. Along the way we point out areas which need further research.

Health risk assessment for nanoparticles: A case for using expert judgment

NASA Astrophysics Data System (ADS)

Kandlikar, Milind; Ramachandran, Gurumurthy; Maynard, Andrew; Murdock, Barbara; Toscano, William A.

2007-01-01

Uncertainties in conventional quantitative risk assessment typically relate to values of parameters in risk models. For many environmental contaminants, there is a lack of sufficient information about multiple components of the risk assessment framework. In such cases, the use of default assumptions and extrapolations to fill in the data gaps is a common practice. Nanoparticle risks, however, pose a new form of risk assessment challenge. Besides a lack of data, there is deep scientific uncertainty regarding every aspect of the risk assessment framework: (a) particle characteristics that may affect toxicity; (b) their fate and transport through the environment; (c) the routes of exposure and the metrics by which exposure ought to be measured; (d) the mechanisms of translocation to different parts of the body; and (e) the mechanisms of toxicity and disease. In each of these areas, there are multiple and competing models and hypotheses. These are not merely parametric uncertainties but uncertainties about the choice of the causal mechanisms themselves and the proper model variables to be used, i.e., structural uncertainties. While these uncertainties exist for PM2.5 as well, risk assessment for PM2.5 has avoided dealing with these issues because of a plethora of epidemiological studies. However, such studies don't exist for the case of nanoparticles. Even if such studies are done in the future, they will be very specific to a particular type of engineered nanoparticle and not generalizable to other nanoparticles. Therefore, risk assessment for nanoparticles will have to deal with the various uncertainties that were avoided in the case of PM2.5. Consequently, uncertainties in estimating risks due to nanoparticle exposures may be characterized as `extreme'. This paper proposes a methodology by which risk analysts can cope with such extreme uncertainty. One way to make these problems analytically tractable is to use expert judgment approaches to study the degree of consensus and/or disagreement between experts on different parts of the exposure-response paradigm. This can be done by eliciting judgments from a wide range of experts on different parts of the risk causal chain. We also use examples to illustrate how studying expert consensus/disagreement helps in research prioritization and budget allocation exercises. The expert elicitation can be repeated over the course of several years, over which time, the state of scientific knowledge will also improve and uncertainties may possibly reduce. Results from expert the elicitation exercise can be used by risk managers or managers of funding agencies as a tool for research prioritization.

Modeling the transport of engineered nanoparticles in saturated porous media - an experimental setup

NASA Astrophysics Data System (ADS)

Braun, A.; Neukum, C.; Azzam, R.

2011-12-01

The accelerating production and application of engineered nanoparticles is causing concerns regarding their release and fate in the environment. For assessing the risk that is posed to drinking water resources it is important to understand the transport and retention mechanisms of engineered nanoparticles in soil and groundwater. In this study an experimental setup for analyzing the mobility of silver and titanium dioxide nanoparticles in saturated porous media is presented. Batch and column experiments with glass beads and two different soils as matrices are carried out under varied conditions to study the impact of electrolyte concentration and pore water velocities. The analysis of nanoparticles implies several challenges, such as the detection and characterization and the preparation of a well dispersed sample with defined properties, as nanoparticles tend to form agglomerates when suspended in an aqueous medium. The analytical part of the experiments is mainly undertaken with Flow Field-Flow Fractionation (FlFFF). This chromatography like technique separates a particulate sample according to size. It is coupled to a UV/Vis and a light scattering detector for analyzing concentration and size distribution of the sample. The advantage of this technique is the ability to analyze also complex environmental samples, such as the effluent of column experiments including soil components, and the gentle sample treatment. For optimization of the sample preparation and for getting a first idea of the aggregation behavior in soil solutions, in sedimentation experiments the effect of ionic strength, sample concentration and addition of a surfactant on particle or aggregate size and temporal dispersion stability was investigated. In general the samples are more stable the lower the concentration of particles is. For TiO2 nanoparticles, the addition of a surfactant yielded the most stable samples with smallest aggregate sizes. Furthermore the suspension stability is increasing with electrolyte concentration. Depending on the dispersing medium the results show that TiO2 nanoparticles tend to form aggregates between 100-200 nm in diameter while the primary particle size is given as 21 nm by the manufacturer. Aggregate sizes are increasing with time. The particle size distribution of the silver nanoparticle samples is quite uniform in each medium. The fresh samples show aggregate sizes between 40 and 45 nm while the primary particle size is 15 nm according to the manufacturer. Aggregate size is only slightly increasing with time during the sedimentation experiments. These results are used as a reference when analyzing the effluent of column experiments.

Scaling up feasibility of the production of solid lipid nanoparticles (SLN).

PubMed

Gohla, S H; Dingler, A

2001-01-01

Solid lipid nanoparticles (SLN/Lipopearls) are widely discussed as colloidal drug carrier system. In contrast to polymeric systems, such as polylactic copolyol capsules, these systems show up with a good biocompatibility, if applied parenterally. The solid lipid matrices can be comprised of fats or waxes and allow protection of incorporated active ingredients against chemical and physical degradation. The SLN can either be produced by "hot homogenisation" of melted lipids at elevated temperatures or a "cold homogenization" process. This paper deals with production technologies for SLN formulations, based on non-ethoxylated fat components for topical application and high pressure homogenization (APV Deutschland GmbH, D-Lübeck). Based on the chosen fat components, a novel and easy manufacturing and scaling up method was developed to maintain chemical and physical integrity of encapsulated active and carrier.

Moving into advanced nanomaterials. Toxicity of rutile TiO{sub 2} nanoparticles immobilized in nanokaolin nanocomposites on HepG2 cell line

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

Bessa, Maria João, E-mail: mjbessa8@gmail.com

Immobilization of nanoparticles on inorganic supports has been recently developed, resulting in the creation of nanocomposites. Concerning titanium dioxide nanoparticles (TiO{sub 2} NPs), these have already been developed in conjugation with clays, but so far there are no available toxicological studies on these nanocomposites. The present work intended to evaluate the hepatic toxicity of nanocomposites (C-TiO{sub 2}), constituted by rutile TiO{sub 2} NPs immobilized in nanokaolin (NK) clay, and its individual components. These nanomaterials were analysed by means of FE-SEM and DLS analysis for physicochemical characterization. HepG2 cells were exposed to rutile TiO{sub 2} NPs, NK clay and C-TiO{sub 2}more » nanocomposite, in the presence and absence of serum for different exposure periods. Possible interferences with the methodological procedures were determined for MTT, neutral red uptake, alamar blue (AB), LDH, and comet assays, for all studied nanomaterials. Results showed that MTT, AB and alkaline comet assay were suitable for toxicity analysis of the present materials after slight modifications to the protocol. Significant decreases in cell viability were observed after exposure to all studied nanomaterials. Furthermore, an increase in HepG2 DNA damage was observed after shorter periods of exposure in the absence of serum proteins and longer periods of exposure in their presence. Although the immobilization of nanoparticles in micron-sized supports could, in theory, decrease the toxicity of single nanoparticles, the selection of a suitable support is essential. The present results suggest that NK clay is not the appropriate substrate to decrease TiO{sub 2} NPs toxicity. Therefore, for future studies, it is critical to select a more appropriate substrate for the immobilization of TiO{sub 2} NPs. - Highlights: • Only the MTT and AB assays were found to be suitable for cytotoxicity assessment. • Alkaline comet assay was also appropriate for genotoxicity evaluation. • All nanomaterials decreased the HepG2 cell viability and caused DNA damage. • Nanokaolin is not a suitable clay substrate for the immobilization of TiO{sub 2} NPs. • Further toxicity studies must be performed in other clays to support nanoparticles.« less

The Stanford Nanocharacterization Laboratory (SNL) and Recent Applications of an Aberration-Corrected Environmental Transmission Electron Microscope

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

Zschech, Ehrenfried; Sinclair, Robert; Kempen, Paul Joseph

2014-04-30

Here, this article describes the establishment, over a period of 10 years or so, of a multi-user, institution-wide facility for the characterization of materials and devices at the nanoscale. Emphasis is placed on the type of equipment that we have found to be most useful for our users, and the business strategy that maintains its operations. A central component of our facility is an aberration-corrected environmental transmission electron microscope and its application is summarized in the studies of plasmon energies of silver nanoparticles, the band gap of PbS quantum dots, atomic site occupancy near grain boundaries in yttria stabilized zirconia,more » the lithiation of silicon nanoparticles, in situ observations on carbon nanotube oxidation and the electron tomography of varicella zoster virus nucleocapsids.« less

Dual-Labeled Near-Infrared/99mTc Imaging Probes Using PAMAM-Coated Silica Nanoparticles for the Imaging of HER2-Expressing Cancer Cells

PubMed Central

Yamaguchi, Haruka; Tsuchimochi, Makoto; Hayama, Kazuhide; Kawase, Tomoyuki; Tsubokawa, Norio

2016-01-01

We sought to develop dual-modality imaging probes using functionalized silica nanoparticles to target human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer cells and achieve efficient target imaging of HER2-expressing tumors. Polyamidoamine-based functionalized silica nanoparticles (PCSNs) for multimodal imaging were synthesized with near-infrared (NIR) fluorescence (indocyanine green (ICG)) and technetium-99m (99mTc) radioactivity. Anti-HER2 antibodies were bound to the labeled PCSNs. These dual-imaging probes were tested to image HER2-overexpressing breast carcinoma cells. In vivo imaging was also examined in breast tumor xenograft models in mice. SK-BR3 (HER2 positive) cells were imaged with stronger NIR fluorescent signals than that in MDA-MB231 (HER2 negative) cells. The increased radioactivity of the SK-BR3 cells was also confirmed by phosphor imaging. NIR images showed strong fluorescent signals in the SK-BR3 tumor model compared to muscle tissues and the MDA-MB231 tumor model. Automatic well counting results showed increased radioactivity in the SK-BR3 xenograft tumors. We developed functionalized silica nanoparticles loaded with 99mTc and ICG for the targeting and imaging of HER2-expressing cells. The dual-imaging probes efficiently imaged HER2-overexpressing cells. Although further studies are needed to produce efficient isotope labeling, the results suggest that the multifunctional silica nanoparticles are a promising vehicle for imaging specific components of the cell membrane in a dual-modality manner. PMID:27399687

Synthesis and properties of a biodegradable polymer-drug conjugate: Methotrexate-poly(glycerol adipate).

PubMed

Suksiriworapong, Jiraphong; Taresco, Vincenzo; Ivanov, Delyan P; Styliari, Ioanna D; Sakchaisri, Krisada; Junyaprasert, Varaporn Buraphacheep; Garnett, Martin C

2018-07-01

Polymer-drug conjugates have been actively developed as potential anticancer drug delivery systems. In this study, we report the first polymer-anticancer drug conjugate with poly(glycerol adipate) (PGA) through the successful conjugation of methotrexate (MTX). MTX-PGA conjugates were controllably and simply fabricated by carbodiimide-mediated coupling reaction with various high molar ratios of MTX. The MTX-PGA conjugate self-assembled into nanoparticles with size dependent on the amount of conjugated MTX and the pH of medium. Change in particle size was attributed to steric hindrance and bulkiness inside the nanoparticle core and dissociation of free functional groups of the drug. The MTX-PGA nanoparticles were physically stable in media with pH range of 5-9 and ionic strength of up to 0.15 M NaCl and further chemically stable against hydrolysis in pH 7.4 medium over 30 days but enzymatically degradable to release unchanged free drug. Although 30%MTX-PGA nanoparticles exhibited only slightly less potency than free MTX in 791T cells in contrast to previously reported human serum albumin-MTX conjugates which had >300 times lower potency than free MTX. However, the MTX nanoparticles showed 7 times higher toxicity to Saos-2 cells than MTX. Together with the enzymic degradation experiments, these results suggest that with a suitable biodegradable polymer a linker moiety is not a necessary component. These easily synthesised PGA drug conjugates lacking a linker moiety could therefore be an effective new pathway for development of polymer drug conjugates. Copyright © 2018 Elsevier B.V. All rights reserved.

Dual-Labeled Near-Infrared/(99m)Tc Imaging Probes Using PAMAM-Coated Silica Nanoparticles for the Imaging of HER2-Expressing Cancer Cells.

PubMed

Yamaguchi, Haruka; Tsuchimochi, Makoto; Hayama, Kazuhide; Kawase, Tomoyuki; Tsubokawa, Norio

2016-07-07

We sought to develop dual-modality imaging probes using functionalized silica nanoparticles to target human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer cells and achieve efficient target imaging of HER2-expressing tumors. Polyamidoamine-based functionalized silica nanoparticles (PCSNs) for multimodal imaging were synthesized with near-infrared (NIR) fluorescence (indocyanine green (ICG)) and technetium-99m ((99m)Tc) radioactivity. Anti-HER2 antibodies were bound to the labeled PCSNs. These dual-imaging probes were tested to image HER2-overexpressing breast carcinoma cells. In vivo imaging was also examined in breast tumor xenograft models in mice. SK-BR3 (HER2 positive) cells were imaged with stronger NIR fluorescent signals than that in MDA-MB231 (HER2 negative) cells. The increased radioactivity of the SK-BR3 cells was also confirmed by phosphor imaging. NIR images showed strong fluorescent signals in the SK-BR3 tumor model compared to muscle tissues and the MDA-MB231 tumor model. Automatic well counting results showed increased radioactivity in the SK-BR3 xenograft tumors. We developed functionalized silica nanoparticles loaded with (99m)Tc and ICG for the targeting and imaging of HER2-expressing cells. The dual-imaging probes efficiently imaged HER2-overexpressing cells. Although further studies are needed to produce efficient isotope labeling, the results suggest that the multifunctional silica nanoparticles are a promising vehicle for imaging specific components of the cell membrane in a dual-modality manner.

How to achieve safe, high-quality clinical studies with non-Medicinal Investigational Products? A practical guideline by using intra-bronchial carbon nanoparticles as case study.

PubMed

Berger, M; Kooyman, P J; Makkee, M; van der Zee, J S; Sterk, P J; van Dijk, J; Kemper, E M

2016-08-19

Clinical studies investigating medicinal products need to comply with laws concerning good clinical practice (GCP) and good manufacturing practice (GMP) to guarantee the quality and safety of the product, to protect the health of the participating individual and to assure proper performance of the study. However, there are no specific regulations or guidelines for non-Medicinal Investigational Products (non-MIPs) such as allergens, enriched food supplements, and air pollution components. As a consequence, investigators will avoid clinical research and prefer preclinical models or in vitro testing for e.g. toxicology studies. 1) briefly review the current guidelines and regulations for Investigational Medicinal Products; 2) present a standardised approach to ensure the quality and safety of non-MIPs in human in vivo research; and 3) discuss some lessons we have learned. We propose a practical line of approach to compose a clarifying product dossier (PD), comprising the description of the production process, the analysis of the raw and final product, toxicological studies, and a thorough risk-benefit-analysis. This is illustrated by an example from a human in vivo research model to study exposure to air pollutants, by challenging volunteers with a suspension of carbon nanoparticles (the component of ink cartridges for laser printers). With this novel risk-based approach, the members of competent authorities are provided with standardised information on the quality of the product in relation to the safety of the participants, and the scientific goal of the study.

Thick film magnetic nanoparticulate composites and method of manufacture thereof

NASA Technical Reports Server (NTRS)

Ge, Shihui (Inventor); Yan, Dajing (Inventor); Xiao, Danny T. (Inventor); Ma, Xinqing (Inventor); Zhang, Yide (Inventor); Zhang, Zongtao (Inventor)

2009-01-01

Thick film magnetic/insulating nanocomposite materials, with significantly reduced core loss, and their manufacture are described. The insulator coated magnetic nanocomposite comprises one or more magnetic components, and an insulating component. The magnetic component comprises nanometer scale particles (about 1 to about 100 nanometers) coated by a thin-layered insulating phase. While the intergrain interaction between the immediate neighboring magnetic nanoparticles separated by the insulating phase provides the desired soft magnetic properties, the insulating material provides high resistivity, which reduces eddy current loss.

Metabolic effects of TiO2 nanoparticles, a common component of sunscreens and cosmetics, on human keratinocytes

PubMed Central

Tucci, P; Porta, G; Agostini, M; Dinsdale, D; Iavicoli, I; Cain, K; Finazzi-Agró, A; Melino, G; Willis, A

2013-01-01

The long-term health risks of nanoparticles remain poorly understood, which is a serious concern given their prevalence in the environment from increased industrial and domestic use. The extent to which such compounds contribute to cellular toxicity is unclear, and although it is known that induction of oxidative stress pathways is associated with this process, the proteins and the metabolic pathways involved with nanoparticle-mediated oxidative stress and toxicity are largely unknown. To investigate this problem further, the effect of TiO2 on the HaCaT human keratinocyte cell line was examined. The data show that although TiO2 does not affect cell cycle phase distribution, nor cell death, these nanoparticles have a considerable and rapid effect on mitochondrial function. Metabolic analysis was performed to identify 268 metabolites of the specific pathways involved and 85 biochemical metabolites were found to be significantly altered, many of which are known to be associated with the cellular stress response. Importantly, the uptake of nanoparticles into the cultured cells was restricted to phagosomes, TiO2 nanoparticles did not enter into the nucleus or any other cytoplasmic organelle. No other morphological changes were detected after 24-h exposure consistent with a specific role of mitochondria in this response. PMID:23519118

Enhancing the methanol tolerance of platinum nanoparticles for the cathode reaction of direct methanol fuel cells through a geometric design.

PubMed

Feng, Yan; Ye, Feng; Liu, Hui; Yang, Jun

2015-11-18

Mastery over the structure of nanoparticles might be an effective way to enhance their performance for a given application. Herein we demonstrate the design of cage-bell nanostructures to enhance the methanol tolerance of platinum (Pt) nanoparticles while remaining their catalytic activity for oxygen reduction reaction. This strategy starts with the synthesis of core-shell-shell nanoparticles with Pt and silver (Ag) residing respectively in the core and inner shell regions, which are then agitated with saturated sodium chloride (NaCl) solution to eliminate the Ag component from the inner shell region, leading to the formation of bimetallic nanoparticles with a cage-bell structure, defined as a movable Pt core enclosed by a metal shell with nano-channels, which exhibit superior methanol-tolerant property in catalyzing oxygen reduction reaction due to the different diffusion behaviour of methanol and oxygen in the porous metal shell of cage-bell structured nanoparticles. In particular, the use of remarkably inexpensive chemical agent (NaCl) to promote the formation of cage-bell structured particles containing a wide spectrum of metal shells highlights its engineering merit to produce highly selective electrocatalysts on a large scale for the cathode reaction of direct methanol fuel cells.

Synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted with mixed hollow sphere template method.

PubMed

Gopi, D; Indira, J; Kavitha, L; Sekar, M; Mudali, U Kamachi

2012-07-01

Hydroxyapatite (HAP) is the main inorganic component of bone material and is widely used in various biomedical applications due to its excellent bioactivity and biocompatibility. In this paper, we have reported the synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted mixed template directed method. In this method glycine-acrylic acid (GLY-AA) hollow spheres were used as an organic template which could be prepared by mixing of glycine with acrylic acid. The as-synthesized HAP nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and tunnelling electron microscope (TEM) to investigate the nature of bonding, crystallinity, size and shape. The thermal stability of as-synthesized nanoparticles was also investigated by the thermo gravimetric analysis (TGA). The effect of ultrasonic irradiation time on the crystallinity and size of the HAP nanoparticles in presence of glycine-acrylic acid hollow spheres template were investigated. From the inspection of the above results it is confirmed that the crystallinity and size of the HAP nanoparticles decrease with increasing ultrasonic irradiation time. Hence the proposed synthesis strategy provides a facile pathway to obtain nano sized HAP with high quality, suitable size and morphology. Copyright © 2012 Elsevier B.V. All rights reserved.

Insights into the binding behavior of bovine serum albumin to black carbon nanoparticles and induced cytotoxicity

NASA Astrophysics Data System (ADS)

Wu, Hai; Chen, Miaomiao; Shang, Mengting; Li, Xiang; Mu, Kui; Fan, Suhua; Jiang, Shuanglin; Li, Wenyong

2018-07-01

Black carbon (BC) is a main component of particulate matter (PM2.5). Due to their small size (<100 nm), inhaled ultrafine BC nanoparticles may penetrate the lung alveoli, where they interact with surfactant proteins and lipids, causing more serious damage to human health. Here, BC was analyzed to investigate the binding mechanism of its interaction with protein and induction of cytotoxicity changes. The binding process and protein conformation between BC and a serum protein (bovine serum albumin, BSA) were monitored by using a fluorescence quenching technique and UV-vis absorption, Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopies. The experimental results revealed that the fluorescence quenching of BSA induced by BC was a static quenching process and the hydrophobic force played the critical role in the interaction. The native conformation of BSA on the BC surface was slightly disturbed but obvious structural unfolding of the secondary structure did not occur. In the cytotoxicity study, BC nanoparticles with low concentrations exhibited strong toxicity towards BEAS-2B cells. However, the toxicity of BC nanoparticles could be mitigated by the presence of BSA. Therefore, proteins in biological fluids likely reduce the toxic effect of BC on human health. These findings delineated the binding mechanism and the toxicity between BC and the BSA-BC system, contributing to the understanding of the biological effects of BC exposure on human health in polluted atmospheres.

Characterization by spectroscopic Ellipsometry, the physical properties of silver nanoparticles.

NASA Astrophysics Data System (ADS)

Coanga, Jean-Maurice

2013-04-01

Physicists are able to change their minds through their experiments. I think it is time to go kick the curse and go further in research if we want a human future. I work in the Nano-Optics and Plasmonics research. I defined with ellipsomètrie the structure of new type of Nano particles of silver. It's same be act quickly to replace the old dirty leaded electronic-connexion chip and by the other hand to find a new way for the heath care of cancer disease by nanoparticles the next killers of bad cells. Silver nanoparticle layers are obtained by Spark Plasma Sintering are investigated as an alternative to lead alloy based material for solder joint in power mechatronics modules. These layers are characterized by mean of conventional techniques that is the dilatometry technique, the resistivity measurement through the van der Pauw method, and the flash laser technique. Furthermore, the nanoparticles of silver layer are deeply studied by UV-Visible spectroscopic ellipsometry. Spectroscopic angles parameters are determined in function of temperature and dielectric constants are deduced and analyzed through an optical model which takes into account a Drude and a Lorentz component within the Bruggeman effective medium approximation (EMA). The relaxation times and the electrical conductivity are plot in function of temperature. The obtained electrical conductivity give significant result in good agreement to those reported by four points electrical measurement method.

Nano-Bio Interactions of Porous and Nonporous Silica Nanoparticles of Varied Surface Chemistry: A Structural, Kinetic, and Thermodynamic Study of Protein Adsorption from RPMI Culture Medium.

PubMed

Lehman, Sean E; Mudunkotuwa, Imali A; Grassian, Vicki H; Larsen, Sarah C

2016-01-26

Understanding complex chemical changes that take place at nano-bio interfaces is of great concern for being able to sustainably implement nanomaterials in key applications such as drug delivery, imaging, and environmental remediation. Typical in vitro assays use cell viability as a proxy to understanding nanotoxicity but often neglect how the nanomaterial surface can be altered by adsorption of solution-phase components in the medium. Protein coronas form on the nanomaterial surface when incubated in proteinaceous solutions. Herein, we apply a broad array of techniques to characterize and quantify protein corona formation on silica nanoparticle surfaces. The porosity and surface chemistry of the silica nanoparticles have been systematically varied. Using spectroscopic tools such as FTIR and circular dichroism, structural changes and kinetic processes involved in protein adsorption were evaluated. Additionally, by implementing thermogravimetric analysis, quantitative protein adsorption measurements allowed for the direct comparison between samples. Taken together, these measurements enabled the extraction of useful chemical information on protein binding onto nanoparticles in solution. Overall, we demonstrate that small alkylamines can increase protein adsorption and that even large polymeric molecules such as poly(ethylene glycol) (PEG) cannot prevent protein adsorption in these systems. The implications of these results as they relate to further understanding nano-bio interactions are discussed.

Cytotoxic effect of silver nanoparticles synthesized from Padina tetrastromatica on breast cancer cell line

NASA Astrophysics Data System (ADS)

Gnana Selvi, B. Clara; Madhavan, J.; Santhanam, Amutha

2016-09-01

In recent years researchers were attracted towards marine sources due to the presence of active components in it. Seaweeds were widely used in pharmaceutical research for their known biological activities. The biological synthesis method of silver nanoparticles (AgNPs) using Padina tetrastromatica seaweed extract and their cytotoxicity against breast cancer MCF-7 cells was reported in this study. The synthesized AgNPs using seaweed extract were subjected to x-ray diffraction, UV-visible spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscope, energy dispersive x-ray, zeta potential to elucidate the structural, morphology, size as well as surface potential parameters. An absorption peak at 430 nm in UV-visible spectrum reveals the excitation and surface plasmon resonance of AgNPs. FE-SEM micrographs exhibits the biosynthesized AgNPs, which are pre-dominantly round shaped and the size ranges between 40-50 nm. The zeta potential value of -27.6 mV confirms the stable nature of biosynthesized silver nanoparticles. Furthermore, the biological synthesized Ag NPs exhibited a dose-dependent cytotoxicity against human breast cancer cell (MCF-7) and the inhibitory concentration (IC50) was found for AgNPs against MCF-7 at 24 h incubation. Biological method of synthesizing silver nanoparticles shows a environmental friendly property which helps in effective electrifying usage in many fields.

Improving DNA double-strand repair inhibitor KU55933 therapeutic index in cancer radiotherapy using nanoparticle drug delivery.

PubMed

Tian, Xi; Lara, Haydee; Wagner, Kyle T; Saripalli, Srinivas; Hyder, Syed Nabeel; Foote, Michael; Sethi, Manish; Wang, Edina; Caster, Joseph M; Zhang, Longzhen; Wang, Andrew Z

2015-12-21

Radiotherapy is a key component of cancer treatment. Because of its importance, there has been high interest in developing agents and strategies to further improve the therapeutic index of radiotherapy. DNA double-strand repair inhibitors (DSBRIs) are among the most promising agents to improve radiotherapy. However, their clinical translation has been limited by their potential toxicity to normal tissue. Recent advances in nanomedicine offer an opportunity to overcome this limitation. In this study, we aim to demonstrate the proof of principle by developing and evaluating nanoparticle (NP) formulations of KU55933, a DSBRI. We engineered a NP formulation of KU55933 using nanoprecipitation method with different lipid polymer nanoparticle formulation. NP KU55933 using PLGA formulation has the best loading efficacy as well as prolonged drug release profile. We demonstrated that NP KU55933 is a potent radiosensitizer in vitro using clonogenic assay and is more effective as a radiosensitizer than free KU55933 in vivo using mouse xenograft models of non-small cell lung cancer (NSCLC). Western blots and immunofluorescence showed NP KU55933 exhibited more prolonged inhibition of DNA repair pathway. In addition, NP KU55933 leads to lower skin toxicity than KU55933. Our study supports further investigations using NP to deliver DSBRIs to improve cancer radiotherapy treatment.

Diagnostic potential for gold nanoparticle-based surface-enhanced Raman spectroscopy to provide colorectal cancer screening using blood serum sample

NASA Astrophysics Data System (ADS)

Lin, Duo; Feng, Shangyuan; Pan, Jianji; Chen, Yanping; Lin, Juqiang; Sun, Liqing; Chen, Rong

2011-11-01

Surface-enhanced Raman spectroscopy (SERS) is a vibrational spectroscopic technique that is capable of probing the biomolecular changes associated with diseased transformation. The objective of our study was to explore gold nanoparticle based SERS to obtain blood serum biochemical information for non-invasive colorectal cancer detection. SERS measurements were performed on two groups of blood serum samples: one group from patients (n = 38) with pathologically confirmed colorectal cancer and the other group from healthy volunteers (control subjects, n = 45). Tentative assignments of the Raman bands in the measured SERS spectra suggested interesting cancer specific biomolecular changes, including an increase in the relative amounts of nucleic acid, a decrease in the percentage of saccharide and proteins contents in the blood serum of colorectal cancer patients as compared to that of healthy subjects. Principal component analysis (PCA) of the measured SERS spectra separated the spectral features of the two groups into two distinct clusters with little overlaps. Linear discriminate analysis (LDA) based on the PCA generated features differentiated the nasopharyngeal cancer SERS spectra from normal SERS spectra with high sensitivity (97.4%) and specificity (100%). The results from this exploratory study demonstrated that gold nanoparticle based SERS serum analysis combined with PCA-LDA has tremendous potential for the non-invasive detection of colorectal cancers.

Diagnostic potential for gold nanoparticle-based surface-enhanced Raman spectroscopy to provide colorectal cancer screening using blood serum sample

NASA Astrophysics Data System (ADS)

Lin, Duo; Feng, Shangyuan; Pan, Jianji; Chen, Yanping; Lin, Juqiang; Sun, Liqing; Chen, Rong

2012-03-01

Surface-enhanced Raman spectroscopy (SERS) is a vibrational spectroscopic technique that is capable of probing the biomolecular changes associated with diseased transformation. The objective of our study was to explore gold nanoparticle based SERS to obtain blood serum biochemical information for non-invasive colorectal cancer detection. SERS measurements were performed on two groups of blood serum samples: one group from patients (n = 38) with pathologically confirmed colorectal cancer and the other group from healthy volunteers (control subjects, n = 45). Tentative assignments of the Raman bands in the measured SERS spectra suggested interesting cancer specific biomolecular changes, including an increase in the relative amounts of nucleic acid, a decrease in the percentage of saccharide and proteins contents in the blood serum of colorectal cancer patients as compared to that of healthy subjects. Principal component analysis (PCA) of the measured SERS spectra separated the spectral features of the two groups into two distinct clusters with little overlaps. Linear discriminate analysis (LDA) based on the PCA generated features differentiated the nasopharyngeal cancer SERS spectra from normal SERS spectra with high sensitivity (97.4%) and specificity (100%). The results from this exploratory study demonstrated that gold nanoparticle based SERS serum analysis combined with PCA-LDA has tremendous potential for the non-invasive detection of colorectal cancers.

Improving DNA double-strand repair inhibitor KU55933 therapeutic index in cancer radiotherapy using nanoparticle drug delivery

NASA Astrophysics Data System (ADS)

Tian, Xi; Lara, Haydee; Wagner, Kyle T.; Saripalli, Srinivas; Hyder, Syed Nabeel; Foote, Michael; Sethi, Manish; Wang, Edina; Caster, Joseph M.; Zhang, Longzhen; Wang, Andrew Z.

2015-11-01

Radiotherapy is a key component of cancer treatment. Because of its importance, there has been high interest in developing agents and strategies to further improve the therapeutic index of radiotherapy. DNA double-strand repair inhibitors (DSBRIs) are among the most promising agents to improve radiotherapy. However, their clinical translation has been limited by their potential toxicity to normal tissue. Recent advances in nanomedicine offer an opportunity to overcome this limitation. In this study, we aim to demonstrate the proof of principle by developing and evaluating nanoparticle (NP) formulations of KU55933, a DSBRI. We engineered a NP formulation of KU55933 using nanoprecipitation method with different lipid polymer nanoparticle formulation. NP KU55933 using PLGA formulation has the best loading efficacy as well as prolonged drug release profile. We demonstrated that NP KU55933 is a potent radiosensitizer in vitro using clonogenic assay and is more effective as a radiosensitizer than free KU55933 in vivo using mouse xenograft models of non-small cell lung cancer (NSCLC). Western blots and immunofluorescence showed NP KU55933 exhibited more prolonged inhibition of DNA repair pathway. In addition, NP KU55933 leads to lower skin toxicity than KU55933. Our study supports further investigations using NP to deliver DSBRIs to improve cancer radiotherapy treatment.

Flash Nanoprecipitation: Particle Structure and Stability

PubMed Central

Pustulka, Kevin M.; Wohl, Adam R.; Lee, Han Seung; Michel, Andrew R.; Han, Jing; Hoye, Thomas R.; McCormick, Alon V.; Panyam, Jayanth; Macosko, Christopher W.

2013-01-01

Flash nanoprecipitation (FNP) is a process that, through rapid mixing, stabilizes an insoluble low molecular weight compound in a nano-sized, polymer-stabilized delivery vehicle. The polymeric components are typically amphiphilic diblock copolymers (BCPs). In order to fully exploit the potential of FNP, factors affecting particle structure, size, and stability must be understood. Here we show that polymer type, hydrophobicity and crystallinity of the small molecule, and small molecule loading levels all affect particle size and stability. Of the four block copolymers (BCP) that we have studied here, poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) (PEG-b-PLGA) was most suitable for potential drug delivery applications due to its ability to give rise to stable nanoparticles, its biocompatibility, and its degradability. We found little difference in particle size when using PLGA block sizes over the range of 5 to 15kDa. The choice of hydrophobic small molecule was important, as molecules with a calculated water-octanol partition coefficient (clogP) below 6 gave rise to particles that were unstable and underwent rapid Ostwald ripening. Studies probing the internal structure of nanoparticles were also performed. Analysis of differential scanning calorimetry (DSC), cryogenic transmission electron microscopy (cryo-TEM), and 1H-NMR experiments support a three-layer core-shell-corona nanoparticle structure. PMID:24053447

Formulation and Characterization of Anthocyanins-Loaded Nanoparticles.

PubMed

Dupeyrón, Danay; Kawakami, Monique; Rieumont, Jacques; Carvalho, José Carlos

2017-01-01

Açaí berry, from the Euterpe oleracea Mart. Palm, has been described as the most important fruit in the Brazilian Amazon. Several studies have reported that anthocyanins (ACNs), one of the components of the açaí, have enormous potential for pharmaceuticals applications. However, the bioavailability of anthocyanins is relatively low compared to that of other flavonoids. Then, in the present work, anthocyanins-loaded nanoparticles have been developed to overcome their poor bioavailability. A two-level factorial design with three factors was considered to evaluate the effect of EUDRAGIT ® L100, polyethylene glycol 2000 (PEG 2000) and polysorbate 80 on encapsulation efficiency (EE) of anthocyanins. Also, major parameters of nanoparticles were assessed by using mainly SEM microscopy and Dynamic light scattering. PEG 2000 was the only individual factor that has statistical significance (95% confidence level). The process yields (PY) were found in between 67% and 92%; the particle size and morphology analysis showed two distribution size, one for NPs and another for the agglomerates. The pH-sensitive polymer together with the hydrophilic polymer showed to be suitable as ACNs delivery system. The delayed release profile of ACNs, observed for all formulations, can enhance their poor bioavailability. Nevertheless, ACNs bioavailability in vivo remains to be studied. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Investigating the effect of poly-l-lactic acid nanoparticles carrying hypericin on the flow-biased diffusive motion of HeLa cell organelles.

PubMed

Penjweini, Rozhin; Deville, Sarah; Haji Maghsoudi, Omid; Notelaers, Kristof; Ethirajan, Anitha; Ameloot, Marcel

2017-07-19

In this study, we investigate in human cervical epithelial HeLa cells the intracellular dynamics and the mutual interaction with the organelles of the poly-l-lactic acid nanoparticles (PLLA NPs) carrying the naturally occurring hydrophobic photosensitizer hypericin. Temporal and spatiotemporal image correlation spectroscopy was used for the assessment of the intracellular diffusion and directed motion of the nanocarriers by tracking the hypericin fluorescence. Using image cross-correlation spectroscopy and specific fluorescent labelling of endosomes, lysosomes and mitochondria, the NPs dynamics in association with the cell organelles was studied. Static colocalization experiments were interpreted according to the Manders' overlap coefficient. Nanoparticles associate with a small fraction of the whole-organelle population. The organelles moving with NPs exhibit higher directed motion compared to those moving without them. The rate of the directed motion drops substantially after the application of nocodazole. The random component of the organelle motions is not influenced by the NPs. Image correlation and cross-correlation spectroscopy are most appropriate to unravel the motion of the PLLA nanocarrier and to demonstrate that the rate of the directed motion of organelles is influenced by their interaction with the nanocarriers. Not all PLLA-hypericin NPs are associated with organelles. © 2017 Royal Pharmaceutical Society.

SERS active colloidal nanoparticles for the detection of small blood biomarkers using aptamers

NASA Astrophysics Data System (ADS)

Marks, Haley; Mabbott, Samuel; Jackson, George W.; Graham, Duncan; Cote, Gerard L.

2015-03-01

Functionalized colloidal nanoparticles for SERS serve as a promising multifunctional assay component for blood biomarker detection. Proper design of these nanoprobes through conjugation to spectral tags, protective polymers, and sensing ligands can provide experimental control over the sensitivity, range, reproducibility, particle stability, and integration with biorecognition assays. Additionally, the optical properties and degree of electromagnetic SERS signal enhancement can be altered and monitored through tuning the nanoparticle shape, size, material and the colloid's local surface plasmon resonance (LSPR). Aptamers, synthetic affinity ligands derived from nucleic acids, provide a number of advantages for biorecognition of small molecules and toxins with low immunogenicity. DNA aptamers are simpler and more economical to produce at large scale, are capable of greater specificity and affinity than antibodies, are easily tailored to specific functional groups, can be used to tune inter-particle distance and shift the LSPR, and their intrinsic negative charge can be utilized for additional particle stability.1,2 Herein, a "turn-off" competitive binding assay platform involving two different plasmonic nanoparticles for the detection of the toxin bisphenol A (BPA) using SERS is presented. A derivative of the toxin is immobilized onto a silver coated magnetic nanoparticle (Ag@MNP), and a second solid silver nanoparticle (AgNP) is functionalized with the BPA aptamer and a Raman reporter molecule (RRM). The capture (Ag@MNP) and probe (AgNP) particles are mixed and the aptamer binding interaction draws the nanoparticles closer together, forming an assembly that results in an increased SERS signal intensity. This aptamer mediated assembly of the two nanoparticles results in a 100x enhancement of the SERS signal intensity from the RRM. These pre-bound aptamer/nanoparticle conjugates were then exposed to BPA in free solution and the competitive binding event was monitored by the decrease in SERS intensity.

Direct Measurement of the Surface Energy of Bimetallic Nanoparticles: Evidence of Vegard's Rulelike Dependence.

PubMed

Chmielewski, Adrian; Nelayah, Jaysen; Amara, Hakim; Creuze, Jérôme; Alloyeau, Damien; Wang, Guillaume; Ricolleau, Christian

2018-01-12

We use in situ transmission electron microscopy to monitor in real time the evaporation of gold, copper, and bimetallic copper-gold nanoparticles at high temperature. Besides, we extend the Kelvin equation to two-component systems to predict the evaporation rates of spherical liquid mono- and bimetallic nanoparticles. By linking this macroscopic model to experimental TEM data, we determine the surface energies of pure gold, pure copper, Cu_{50}Au_{50}, and Cu_{25}Au_{75} nanoparticles in the liquid state. Our model suggests that the surface energy varies linearly with the composition in the liquid Cu-Au nanoalloy; i.e., it follows a Vegard's rulelike dependence. To get atomic-scale insights into the thermodynamic properties of Cu-Au alloys on the whole composition range, we perform Monte Carlo simulations employing N-body interatomic potentials. These simulations at a microscopic level confirm the Vegard's rulelike behavior of the surface energy obtained from experiments combined with macroscopic modeling.

Modeling Oblique Impact Dynamics of Particle-Laden Nanodroplets

NASA Astrophysics Data System (ADS)

Yong, Xin; Qin, Shiyi

2016-11-01

A fundamental understanding of the impact dynamics of nanoscopic droplets laden with nanoparticles has important implications for materials printing and thin film processing. Using many-body dissipative particle dynamics (MDPD), we model nanometer sized suspension droplets imping on dry solid substrate with oblique angles, and compare their behavior with pure liquid droplets. Equilibrated floating droplets containing two types of nanoparticles, namely fully-wetted hydrophilic particles and surface-active Janus particles, impact onto the solid surface with varying initial velocities and impact angles. The velocity components in the normal and tangential directions to the substrate defines normal and tangential Reynolds and Weber numbers, which are used to classify impact regimes. Droplets with nanoparticles dispersed in the bulk and covering the droplet surface (resembling liquid marbles) exhibit quite different behavior in the course of impact. We also reveal the influences of substrate wettability and its interaction with nanoparticles on the impact dynamics. In addition, the vapor film beneath an impinging droplet shows no significant effect on the impact dynamics in our MDPD simulations.

Direct Measurement of the Surface Energy of Bimetallic Nanoparticles: Evidence of Vegard's Rulelike Dependence

NASA Astrophysics Data System (ADS)

Chmielewski, Adrian; Nelayah, Jaysen; Amara, Hakim; Creuze, Jérôme; Alloyeau, Damien; Wang, Guillaume; Ricolleau, Christian

2018-01-01

We use in situ transmission electron microscopy to monitor in real time the evaporation of gold, copper, and bimetallic copper-gold nanoparticles at high temperature. Besides, we extend the Kelvin equation to two-component systems to predict the evaporation rates of spherical liquid mono- and bimetallic nanoparticles. By linking this macroscopic model to experimental TEM data, we determine the surface energies of pure gold, pure copper, Cu50 Au50 , and Cu25 Au75 nanoparticles in the liquid state. Our model suggests that the surface energy varies linearly with the composition in the liquid Cu-Au nanoalloy; i.e., it follows a Vegard's rulelike dependence. To get atomic-scale insights into the thermodynamic properties of Cu-Au alloys on the whole composition range, we perform Monte Carlo simulations employing N -body interatomic potentials. These simulations at a microscopic level confirm the Vegard's rulelike behavior of the surface energy obtained from experiments combined with macroscopic modeling.

Diffractive optical devices produced by light-assisted trapping of nanoparticles.

PubMed

Muñoz-Martínez, J F; Jubera, M; Matarrubia, J; García-Cabañes, A; Agulló-López, F; Carrascosa, M

2016-01-15

One- and two-dimensional diffractive optical devices have been fabricated by light-assisted trapping and patterning of nanoparticles. The method is based on the dielectrophoretic forces appearing in the vicinity of a photovoltaic crystal, such as Fe:LiNbO3, during or after illumination. By illumination with the appropriate light distribution, the nanoparticles are organized along patterns designed at will. One- and two-dimensional diffractive components have been achieved on X- and Z-cut Fe:LiNbO3 crystals, with their polar axes parallel and perpendicular to the crystal surface, respectively. Diffraction gratings with periods down to around a few micrometers have been produced using metal (Al, Ag) nanoparticles with radii in the range of 70-100 nm. Moreover, several 2D devices, such as Fresnel zone plates, have been also produced showing the potential of the method. The diffractive particle patterns remain stable when light is removed. A method to transfer the diffractive patterns to other nonphotovoltaic substrates, such as silica glass, has been also reported.

Photothermal therapy with immune-adjuvant nanoparticles together with checkpoint blockade for effective cancer immunotherapy

NASA Astrophysics Data System (ADS)

Chen, Qian; Xu, Ligeng; Liang, Chao; Wang, Chao; Peng, Rui; Liu, Zhuang

2016-10-01

A therapeutic strategy that can eliminate primary tumours, inhibit metastases, and prevent tumour relapses is developed herein by combining adjuvant nanoparticle-based photothermal therapy with checkpoint-blockade immunotherapy. Indocyanine green (ICG), a photothermal agent, and imiquimod (R837), a Toll-like-receptor-7 agonist, are co-encapsulated by poly(lactic-co-glycolic) acid (PLGA). The formed PLGA-ICG-R837 nanoparticles composed purely by three clinically approved components can be used for near-infrared laser-triggered photothermal ablation of primary tumours, generating tumour-associated antigens, which in the presence of R837-containing nanoparticles as the adjuvant can show vaccine-like functions. In combination with the checkpoint-blockade using anti-cytotoxic T-lymphocyte antigen-4 (CTLA4), the generated immunological responses will be able to attack remaining tumour cells in mice, useful in metastasis inhibition, and may potentially be applicable for various types of tumour models. Furthermore, such strategy offers a strong immunological memory effect, which can provide protection against tumour rechallenging post elimination of their initial tumours.

Effective anodic oxidation of naproxen by platinum nanoparticles coated FTO glass.

PubMed

Chin, Ching-Ju Monica; Chen, Tsan-Yao; Lee, Menshan; Chang, Chiung-Fen; Liu, Yu-Ting; Kuo, Yu-Tsun

2014-07-30

This study investigated applications of the electrochemical anodic oxidation process with Pt-FTO and Pt/MWCNTs-FTO glasses as anodes on the treatment of one of the most important emerging contaminants, naproxen. The anodes used in this study have been synthesized using commercial FTO, MWCNTs and Pt nanoparticles (PtNP). XRD patterns of Pt nanoparticles coated on FTO and MWCNTs revealed that MWCNTs can prevent the surface of PtNPs from sintering and thus provide a greater reaction sites density to interact with naproxen, which have also been confirmed by higher degradation and mineralization efficiencies in the Pt/MWCNTs-FTO system. Results from the CV analysis showed that the Pt-FTO and Pt/MWCNTs-FTO electrodes possessed dual functions of decreasing activation energy and interactions between hydroxyl radicals to effectively degrade naproxen. The lower the solution pH value, the better the degradation efficiency. The existence of humic acid indeed inhibited the degradation ability of naproxen due to the competitions in the multiple-component system. The electrochemical degradation processes were controlled by diffusion mechanism and two major intermediates of 2-acetyl-6-methoxynaphthalene and 2-(6-Hydroxy-2-naphthyl)propanoic acid were identified. This study has successfully demonstrated new, easy, flexible and effective anodic materials which can be feasibly applied to the electrochemical oxidation of naproxen. Copyright © 2014 Elsevier B.V. All rights reserved.

Study of the transverse and longitudinal electric field components of surface plasmon polaritons on flat metal film by polarization-resolved Fourier-space microscopy

NASA Astrophysics Data System (ADS)

Liu, C.; Ong, H. C.

2018-01-01

We have employed a polarization-resolved Fourier-space surface plasmon resonance microscope to determine the electric field component ratio of surface plasmon polaritons (SPPs) propagating on a flat gold film. By using a metallic nanoparticle as a probe to capture the radiation damping of the SPP scattered waves, we find the angular far-field distribution is related to the transverse and longitudinal fields of SPPs. The experiment is supported by analytical and numerical calculations. Our results present a simple but useful approach to probe the behaviors of SPPs such as the transverse spin density as well as the energy density.

Nested plasmonic resonances: extraordinary enhancement of linear and nonlinear interactions.

PubMed

de Ceglia, Domenico; Vincenti, Maria Antonietta; Akozbek, Neset; Bloemer, Mark J; Scalora, Michael

2017-02-20

Plasmonic resonators can provide large local electric fields when the gap between metal components is filled with an ordinary dielectric. We consider a new concept consisting of a hybrid nanoantenna obtained by introducing a resonant, plasmonic nanoparticle strategically placed inside the gap of an aptly sized metallic antenna. The system exhibits two nested, nearly overlapping plasmonic resonances whose signature is a large field enhancement at the surface and within the bulk of the plasmonic nanoparticle that leads to unusually strong, linear and nonlinear light-matter coupling.

Casting inorganic structures with DNA molds

PubMed Central

Sun, Wei; Boulais, Etienne; Hakobyan, Yera; Wang, Wei Li; Guan, Amy; Bathe, Mark; Yin, Peng

2014-01-01

We report a general strategy for designing and synthesizing inorganic nanostructures with arbitrarily prescribed three-dimensional shapes. Computationally designed DNA strands self-assemble into a stiff “nano-mold” that contains a user-specified three-dimensional cavity and encloses a nucleating gold “seed”. Under mild conditions, this seed grows into a larger cast structure that fills and thus replicates the cavity. We synthesized a variety of nanoparticles with three nanometer resolution: three distinct silver cuboids with three independently tunable dimensions, silver and gold nanoparticles with diverse cross sections, and composite structures with homo-/heterogeneous components. The designer equilateral silver triangular and spherical nanoparticles exhibited plasmonic properties consistent with electromagnetism-based simulations. Our framework is generalizable to more complex geometries and diverse inorganic materials, offering a range of applications in biosensing, photonics, and nanoelectronics. PMID:25301973

Solution of system of multidimensional differential equations in X for identification of gold nanoparticles on fibers with elimination of uncertainty

NASA Astrophysics Data System (ADS)

Dobrovolskaya, T. A.; Emelyanov, V. M.; Emelyanov, V. V.

2018-05-01

There are the results of the compilation and solution of a system of multidimensional differential correlation equations of distribution ellipses in the identification of colloidal gold nanoparticles on polyester fibers with multi-dimensional correlation components of Raman polarization spectra. A proposed method is to increase the accuracy and speed of identification of silver nanoparticles on polyester fibers, taking into account the longitudinal and transverse polarization of laser radiation over the entire spectral range, analyzing in sequence and in order simultaneously two peaks along the X-transverse and along the Y-along the fibers. During a solution of the system using a nonlinear quadratic and differential equation with respect to X, an uncertainty arises, the elimination of which is numerical addition Δ = + 0.02985

The effects of prolonged oral administration of gold nanoparticles on the morphology of hematopoietic and lymphoid organs

NASA Astrophysics Data System (ADS)

Bucharskaya, Alla B.; Pakhomy, Svetlana S.; Zlobina, Olga V.; Maslyakova, Galina N.; Navolokin, Nikita A.; Matveeva, Olga V.; Khlebtsov, Boris N.; Bogatyrev, Vladimir A.; Khlebtsov, Nikolai G.; Tuchin, Valery V.

2017-02-01

Currently, the usage of gold nanoparticles as photosensitizers and immunomodulators for plasmonic photothermal therapy has attracted a great attention of researches and end-users. In our work, the influence of prolonged peroral administration of gold nanoparticles (GNPs) with different sizes on the morphological changes of hematopoietic and lymphoid organs was investigated. The 24 white outbred male rats weighing 180-220 g were randomly divided into groups and administered orally for 30 days the suspension of gold nanospheres with diameters of 2, 15 and 50 nm at a dosage of 190 μg/kg of animal body weight. To prevent GNPs aggregation in a tissue and enhance biocompatibility, they were functionalized with thiolated polyethylene glycol. The withdrawal of the animals from the experiment and sampling of spleen, lymph nodes and bone marrow tissues for morphological study were performed a day after the last administration. In the spleen the boundary between the red and white pulp was not clearly differ in all experimental groups, lymphoid follicles were significantly increased in size, containing bright germinative centers represented by large blast cells. The stimulation of lymphocyte and myelocytic series of hematopoiesis was recorded at morphological study of the bone marrow. The number of immunoblasts and large lymphocytes was increased in all structural zones of lymph nodes. The more pronounced changes were found in the group with administration of 15 nm nanoparticles. Thus, the morphological changes of cellular components of hematopoietic organs have size-dependent character and indicate the activation of the migration, proliferation and differentiation of immune cells after prolonged oral administration of GNPs.

Multifunctional paper strip based on GO-veiled Ag nanoparticles with highly SERS sensitive and deliverable properties for high-performance molecular detection.

PubMed

Yang, Cheng; Xu, Yuanyuan; Wang, Minghong; Li, Tianming; Huo, Yanyan; Yang, Chuanxi; Man, Baoyuan

2018-04-16

The development of paper-based SERS substrates that can allow multi-component detection in real-word scenarios is of great value for applications in molecule detection under complex conditions. Here, a multifunctional SERS-based paper sensing substrate has been developed through the uniform patterning of high-density arrays of GO-isolated Ag nanoparticles on the hydrophilic porous cellulose paper strip (GO@AgNP@paper). Wet-chemical synthesis was used to provide the cover of SERS hot spots on any part of the paper, not just limited surface deposition. In virtue of the inherent ability of paper to deliver analytes by the capillary force, the detection ability of the GO@AgNP@paper substrate was greatly promoted, allowing as low as 10 -19 M R6G detection from microliter-volume (50 μL) samples. For the components with different polarity, the paper substrate can be used as an all-in-one machine to achieve the integration of separation and high-sensitive detection for ultralow mixture components, which improves the practical application value of SERS-based paper devices.

A novel in situ hydrophobic ion paring (HIP) formulation strategy for clinical product selection of a nanoparticle drug delivery system.

PubMed

Song, Young Ho; Shin, Eyoung; Wang, Hong; Nolan, Jim; Low, Susan; Parsons, Donald; Zale, Stephen; Ashton, Susan; Ashford, Marianne; Ali, Mir; Thrasher, Daniel; Boylan, Nicholas; Troiano, Greg

2016-05-10

The present studies were aimed at formulating AZD2811-loaded polylactic acid-polyethylene glycol (PLA-PEG) nanoparticles with adjustable release rates without altering the chemical structures of the polymer or active pharmaceutical ingredient (API). This was accomplished through the use of a hydrophobic ion pairing approach. A series of AZD2811-containing nanoparticles with a variety of hydrophobic counterions including oleic acid, 1-hydroxy-2-naphthoic acid, cholic acid, deoxycholic acid, dioctylsulfosuccinic acid, and pamoic acid is described. The hydrophobicity of AZD2811 was increased through formation of ion pairs with these hydrophobic counterions, producing nanoparticles with exceptionally high drug loading-up to five fold higher encapsulation efficiency and drug loading compared to nanoparticles made without hydrophobic ion pairs. Furthermore, the rate at which the drug was released from the nanoparticles could be controlled by employing counterions with various hydrophobicities and structures, resulting in release half-lives ranging from about 2 to 120h using the same polymer, nanoparticle size, and nanoemulsion process. Process recipe variables affecting drug load and release rate were identified, including pH and molarity of quench buffer. Ion pair formation between AZD2811 and pamoic acid as a model counterion was investigated using solubility enhancement as well as nuclear magnetic resonance spectroscopy to demonstrate solution-state interactions. Further evidence for an ion pairing mechanism of controlled release was provided through the measurement of API and counterion release profiles using high-performance liquid chromatography, which had stoichiometric relationships. Finally, Raman spectra of an AZD2811-pamoate salt compared well with those of the formulated nanoparticles, while single components (AZD2811, pamoic acid) alone did not. A library of AZD2811 batches was created for analytical and preclinical characterization. Dramatically improved preclinical efficacy and tolerability data were generated for the pamoic acid lead formulation, which has been selected for evaluation in a Phase 1 clinical trial (ClinicalTrials.gov Identifier NCT 02579226). This work clearly demonstrates the importance of assessing a wide range of drug release rates during formulation screening as a critical step for new drug product development, and how utilizing hydrophobic ion pairing enabled this promising nanoparticle formulation to proceed into clinical development. Copyright © 2016 Elsevier B.V. All rights reserved.

Aerolization During Boron Nanoparticle Multi-Component Fuel Group Burning Studies

DTIC Science & Technology

2014-02-03

Anderson, University of Utah). …………………… 14 Figure 2. Photograph of group burning facility showing benchtop flat flame burner unit with injector nozzle ...and (B) aerosol generator. 16 Figure 6. Diagram of benchtop flat flame burner unit showing injector nozzle assembly with VOAG orifice, fuel and...translation stage, variable fuel and gas supply rates, and injector nozzles that can be configured to investigate diffusion and premixed flames (Fig. 2 & 3

Characterization of the Interactions between Titanium Dioxide Nanoparticles and Polymethoxyflavones Using Surface-Enhanced Raman Spectroscopy.

PubMed

Cao, Xiaoqiong; Ma, Changchu; Gao, Zili; Zheng, Jinkai; He, Lili; McClements, David Julian; Xiao, Hang

2016-12-14

Nanosized titanium dioxide (TiO 2 ) particles are commonly present in TiO 2 food additives (E171) and have been associated with potential adverse effects on health. However, little knowledge is available regarding the interactions between TiO 2 nanoparticles (NPs) and other food components, such as flavonoids. In this study, we aim to study the molecular interactions between TiO 2 anatase NPs and three structurally closely related polymethoxyflavones (PMFs, flavonoids found in citrus fruits), namely, 3',4'-didemethylnobiletin (DDN), 5-demethylnobiletin (5DN), and 5,3',4'-tridemethylnobiletin (TDN), using ultraviolet-visible (UV-vis) spectrometry and surface-enhanced Raman spectroscopy (SERS). In the UV-vis absorption spectra, bathochromic effects were observed after DDN and TDN conjugated with TiO 2 NPs. The results from SERS analysis clearly demonstrated that DDN and TDN could bind TiO 2 NPs with the functional groups 3'-OH and 4'-OH on ring B and formed charge-transfer complexes. However, 5DN with functional groups C═O on ring C and 5-OH on ring A could not bind TiO 2 NPs. Knowledge on the molecular interactions between TiO 2 NPs and food components, such as flavonoids, will facilitate the understanding of the fate of TiO 2 NPs during food processing and in the gastrointestinal tract after oral consumption.

Partial least squares analysis and mixture design for the study of the influence of composition variables on lipidic nanoparticle characteristics.

PubMed

Malzert-Fréon, A; Hennequin, D; Rault, S

2010-11-01

Lipidic nanoparticles (NP), formulated from a phase inversion temperature process, have been studied with chemometric techniques to emphasize the influence of the four major components (Solutol®, Labrasol®, Labrafac®, water) on their average diameter and their distribution in size. Typically, these NP present a monodisperse size lower than 200 nm, as determined by dynamic light scattering measurements. From the application of the partial least squares (PLS) regression technique to the experimental data collected during definition of the feasibility zone, it was established that NP present a core-shell structure where Labrasol® is well encapsulated and contributes to the structuring of the NP. Even if this solubility enhancer is regarded as a pure surfactant in the literature, it appears that the oil moieties of this macrogolglyceride mixture significantly influence its properties. Furthermore, results have shown that PLS technique can be also used for predictions of sizes for given relative proportions of components and it was established that from a mixture design, the quantitative mixture composition to use in order to reach a targeted size and a targeted polydispersity index (PDI) can be easily predicted. Hence, statistical models can be a useful tool to control and optimize the characteristics in size of NP. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Nanomaterials in cancer-therapy drug delivery system.

PubMed

Zhang, Gen; Zeng, Xin; Li, Ping

2013-05-01

Nanomaterials can enhance the delivery and treatment efficiency of anti-cancer drugs, and the mechanisms of the tumor-reducing activity of nanomaterials with cancer drug have been investigated. The task for drug to reach pathological areas has facilitated rapid advances in nanomedicine. Herein, we summarize promising findings with respect to cancer therapeutics based on nano-drug delivery vectors. Relatively high toxicity of uncoated nanoparticles restricts the use of these materials in humans. In order to reduce toxicity, many approaches have focused on the encapsulation of nanoparticles with biocompatible materials. Efficient delivery systems have been developed that utilized nanoparticles loaded with high dose of cancer drug in the presence of bilayer molecules. Well-established nanotechnologies have been designed for drug delivery with specific bonding. Surface-modified nanoparticles as vehicles for drug delivery system that contains multiple nano-components, each specially designed to achieve aimed task for the emerging application delivery of therapeutics. Drug-coated polymer nanoparticles could efficiently increase the intracellular accumulation of anti-cancer drugs. This review also introduces the nanomaterials with drug on the induction of apoptosis in cancer cells in vitro and in vivo. Direct interactions between the particles and cellular molecules to cause adverse biological responses are also discussed.

Structure and organization of phospholipid/polysaccharide nanoparticles

NASA Astrophysics Data System (ADS)

Gerelli, Y.; Di Bari, M. T.; Deriu, A.; Cantù, L.; Colombo, P.; Como, C.; Motta, S.; Sonvico, F.; May, R.

2008-03-01

In recent years nanoparticles and microparticles composed of polymeric or lipid material have been proposed as drug carriers for improving the efficacy of encapsulated drugs. For the production of these systems different materials have been proposed, among them phospholipids and polysaccharides due to their biocompatibility, biodegradability, low cost and safety. We report here a morphological and structural investigation, performed using cryo-TEM, static light scattering and small angle neutron and x-ray scattering, on phospholipid/saccharide nanoparticles loaded with a lipophilic positively charged drug (tamoxifen citrate) used in breast cancer therapy. The lipid component was soybean lecithin; the saccharide one was chitosan that usually acts as an outer coating increasing vesicle stability. The microscopy and scattering data indicate the presence of two distinct nanoparticle families: uni-lamellar vesicles with average radius 90 Å and multi-lamellar vesicles with average radius 440 Å. In both families the inner core is occupied by the solvent. The presence of tamoxifen gives rise to a multi-lamellar structure of the lipid outer shell. It also induces a positive surface charge into the vesicles, repelling the positively charged chitosan molecules which therefore do not take part in nanoparticle formation.

Nanoparticles in forensic science

NASA Astrophysics Data System (ADS)

Cantu, Antonio A.

2008-10-01

Nanoparticles appear in several areas of forensic science including security documents, paints, inks, and reagents that develop latent prints. One reagent (known as the silver physical developer) that visualizes the water insoluble components of latent print residue is based on the formation of highly charged silver nanoparticles. These attach to and grow on the residue and generate a silver image. Another such reagent involves highly charged gold nanoparticles. These attach to the residue forming a weak gold image which can be amplified with a silver physical developer. Nanoparaticles are also used in items such as paints, printing inks, and writing inks. Paints and most printing inks consist of nano-sized pigments in a vehicle. However, certain modern ink jet printing inks now contain nano-sized pigments to improve their light fastness and most gel inks are also based on nano scale pigments. These nanoparticlecontaining materials often appear as evidence and are thus subject to forensic characterization. Both luminescent (quantum dots), up-converting nano scale phosphors, and non luminescent nanoparticles are used as security tags to label product, add security to documents, and as anti counterfeiting measures. These assist in determining if an item is fraudulently made.

Adverse Biological Effect of TiO2 and Hydroxyapatite Nanoparticles Used in Bone Repair and Replacement

PubMed Central

Wang, Jiangxue; Wang, Liting; Fan, Yubo

2016-01-01

The adverse biological effect of nanoparticles is an unavoidable scientific problem because of their small size and high surface activity. In this review, we focus on nano-hydroxyapatite and TiO2 nanoparticles (NPs) to clarify the potential systemic toxicological effect and cytotoxic response of wear nanoparticles because they are attractive materials for bone implants and are widely investigated to promote the repair and reconstruction of bone. The wear nanoparticles would be prone to binding with proteins to form protein-particle complexes, to interacting with visible components in the blood including erythrocytes, leukocytes, and platelets, and to being phagocytosed by macrophages or fibroblasts to deposit in the local tissue, leading to the formation of fibrous local pseudocapsules. These particles would also be translocated to and disseminated into the main organs such as the lung, liver and spleen via blood circulation. The inflammatory response, oxidative stress, and signaling pathway are elaborated to analyze the potential toxicological mechanism. Inhibition of the oxidative stress response and signaling transduction may be a new therapeutic strategy for wear debris–mediated osteolysis. Developing biomimetic materials with better biocompatibility is our goal for orthopedic implants. PMID:27231896

Effect of organometallic fuel additives on nanoparticle emissions from a gasoline passenger car.

PubMed

Gidney, Jeremy T; Twigg, Martyn V; Kittelson, David B

2010-04-01

Particle size measurements were performed on the exhaust of a car operating on a chassis dynamometer fueled with standard gasoline and gasoline containing low levels of Pb, Fe, and Mn organometallic additives. When additives were present there was a distinct nucleation mode consisting primarily of sub-10 nm nanoparticles. At equal molar dosing Mn and Fe gave similar nanoparticle concentrations at the tailpipe, whereas Pb gave a considerably lower concentration. A catalytic stripper was used to remove the organic component of these particles and revealed that they were mainly solid and, because of their association with inorganic additives, presumably inorganic. Solid nucleation mode nanoparticles of similar size and concentration to those observed here from a gasoline engine with Mn and Fe additives have also been observed from modern heavy-duty diesel engines without aftertreatment at idle, but these solid particles are a small fraction of the primarily volatile nucleation mode particles emitted. The solid nucleation mode particles emitted by the diesel engines are likely derived from metal compounds in the lubrication oil, although carbonaceous particles cannot be ruled out. Significantly, most of these solid nanoparticles emitted by both engine types fall below the 23 nm cutoff of the PMP number regulation.

Nanoparticle-wetted surfaces for relays and energy transmission contacts.

PubMed

Voevodin, Andrey A; Vaia, Richard A; Patton, Steven T; Diamanti, Steven; Pender, Mark; Yoonessi, Mitra; Brubaker, Jennifer; Hu, Jian-Jun; Sanders, Jeffrey H; Phillips, Benjamin S; MacCuspie, Robert I

2007-11-01

Submonolayer coatings of noble-metal nanoparticle liquids (NPLs) are shown to provide replenishable surfaces with robust asperities and metallic conductivity that extends the durability of electrical relays by 10 to 100 times (depending on the current driven through the contact) as compared to alternative approaches. NPLs are single-component materials consisting of a metal nanoparticle core (5-20 nm Au or Pt nanoparticles) surrounded by a covalently tethered ionic-liquid corona of 1.5 to 2 nm. Common relay failure modes, such as stiction, surface distortion, and contact shorting, are suppressed with the addition of a submonolayer of NPLs to the contact surfaces. This distribution of NPLs results in a force profile for a contact-retraction cycle that is distinct from bare Au contacts and thicker, multilayer coatings of NPLs. Postmortem examination reveals a substantial decrease in topological change of the electrode surface relative to bare contacts, as well as an indication of lateral migration of the nanoparticles from the periphery towards the contact. A general extension of this concept to dynamic physical interfaces experiencing impact, sliding, or rolling affords alternatives to increase reliability and reduced losses for transmittance of electrical and mechanical energy.

A Conductometric Indium Oxide Semiconducting Nanoparticle Enzymatic Biosensor Array

PubMed Central

Lee, Dongjin; Ondrake, Janet; Cui, Tianhong

2011-01-01

We report a conductometric nanoparticle biosensor array to address the significant variation of electrical property in nanomaterial biosensors due to the random network nature of nanoparticle thin-film. Indium oxide and silica nanoparticles (SNP) are assembled selectively on the multi-site channel area of the resistors using layer-by-layer self-assembly. To demonstrate enzymatic biosensing capability, glucose oxidase is immobilized on the SNP layer for glucose detection. The packaged sensor chip onto a ceramic pin grid array is tested using syringe pump driven feed and multi-channel I–V measurement system. It is successfully demonstrated that glucose is detected in many different sensing sites within a chip, leading to concentration dependent currents. The sensitivity has been found to be dependent on the channel length of the resistor, 4–12 nA/mM for channel lengths of 5–20 μm, while the apparent Michaelis-Menten constant is 20 mM. By using sensor array, analytical data could be obtained with a single step of sample solution feeding. This work sheds light on the applicability of the developed nanoparticle microsensor array to multi-analyte sensors, novel bioassay platforms, and sensing components in a lab-on-a-chip. PMID:22163696

Reduced graphene oxide supported gold nanoparticles for electrocatalytic reduction of carbon dioxide

NASA Astrophysics Data System (ADS)

Saquib, Mohammad; Halder, Aditi

2018-02-01

Electrochemical reduction of carbon dioxide is one of the methods which have the capability to recycle CO2 into valuable products for energy and industrial applications. This research article describes about a new electrocatalyst "reduced graphene oxide supported gold nanoparticles" for selective electrochemical conversion of carbon dioxide to carbon monoxide. The main aim for conversion of CO2 to CO lies in the fact that the latter is an important component of syn gas (a mixture of hydrogen and carbon monoxide), which is then converted into liquid fuel via well-known industrial process called Fischer-Tropsch process. In this work, we have synthesized different composites of the gold nanoparticles supported on defective reduced graphene oxide to evaluate the catalytic activity of reduced graphene oxide (RGO)-supported gold nanoparticles and the role of defective RGO support towards the electrochemical reduction of CO2. Electrochemical and impedance measurements demonstrate that higher concentration of gold nanoparticles on the graphene support led to remarkable decrease in the onset potential of 240 mV and increase in the current density for CO2 reduction. Lower impedance and Tafel slope values also clearly support our findings for the better performance of RGOAu than bare Au for CO2 reduction.

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.

Optical properties modification induced by laser radiation in noble-metal-doped glasses

NASA Astrophysics Data System (ADS)

Nedyalkov, N.; Stankova, N. E.; Koleva, M. E.; Nikov, R.; Atanasov, P.; Grozeva, M.; Iordanova, E.; Yankov, G.; Aleksandrov, L.; Iordanova, R.; Karashanova, D.

2018-03-01

We present results on laser-induced color changes in gold- and silver-doped glass. The doped borosilicate glass was prepared by conventional melt quenching. The study was focused on the change of the optical properties after irradiation of the glass by femtosecond laser pulses. Under certain conditions, the laser radiation induces defects associated with formation of color centers in the material. We studied this process in a broad range of laser radiation wavelengths – from UV to IR, and observed changes in the color of the irradiated areas after annealing of the processed glass samples, the color being red for the gold-doped glass red and yellow for the silver-doped glass. The structural and morphological analyses performed indicated that this effect is related to formation of metal nanoparticles inside the material. The results obtained show that femtosecond laser processing of noble-metal-doped glasses can be used for fabrication of 3D-nanoparticles systems in transparent materials with application as novel optical components.

Self-Assembly of Heterogeneously Shaped Nanoparticles into Plasmonic Metamolecules on DNA Origami.

PubMed

Liu, Wenyan; Li, Ling; Yang, Shuo; Gao, Jie; Wang, Risheng

2017-10-12

Fabrication of plasmonic metamolecules (PMs) with rationally designed complexity is one of the major goals of nanotechnology. Most self-assembled PMs, however, have been constructed using single-component systems. The corresponding plasmonic assemblies still suffer from the lack of complexity, which is required to achieve a high degree of functionality. Here, we report a general applicable strategy that can realize a series of high-ordered hetero-PMs using bottom-up DNA self-assembly. DNA-functionalized differently shaped nanoparticles were deliberately arranged in prescribed positions on 3D triangular DNA origami frames to form various hetero-PMs. Importantly, we showed that the optical properties of assembled PMs could be facially tuned by selectively regulating the position of each component. This method provides a promising pathway for manufacturing more complex and advanced materials by integrating diverse nanocomponents with particular properties. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.