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Sample records for nanoparticles incorporating kaempferol

  1. SERS spectroscopy of kaempferol and galangin under the interaction of human serum albumin with adsorbed silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Bai, Xueyuan; Wang, Yingping; Zhao, Bing; Zhao, Daqing; Zhao, Yu

    Raman and surface-enhanced Raman scattering (SERS) spectroscopy were employed to probe the interaction of the flavonol drugs, kaempferol and galangin, with human serum albumin (HSA). SERS spectra of both flavonol derivatives were obtained from a colloidal silver surface in physiological condition, based on the high performance of the enhanced substrate, the most enhanced modes of kaempferol and galangin were those with certain motions perpendicular to the metal surface. The SERS spectra were allowed to predict similar orientation geometry for both of the drugs on the colloidal surface with minor difference. In addition, both flavonols-HSA complexes were prepared in different concentration ratios and the orientated differences between kaempferol and galangin were investigated by SERS.

  2. Incorporation of metal nanoparticles into wood substrate and methods

    SciTech Connect

    Rector, Kirk D; Lucas, Marcel

    2015-11-04

    Metal nanoparticles were incorporated into wood. Ionic liquids were used to expand the wood cell wall structure for nanoparticle incorporation into the cell wall structure. Nanoparticles of elemental gold or silver were found to be effective surface enhanced Raman spectroscopy (SERS) imaging contrast or sensing agents. Nanoparticles of elemental iron were found to be efficient microwave absorbers and caused localized heating for disrupting the integrity of the lignocellulosic matrix. Controls suggest that the localized heating around the iron nanoparticles reduces losses of cellulose in the form of water, volatiles and CO.sub.2. The ionic liquid is needed during the incorporation process at room temperature. The use of small amounts of ionic liquid combined with the absence of an ionic liquid purification step and a lower energy and water use are expected to reduce costs in an up-scaled pretreatment process.

  3. Incorporation of platinum nanoparticles in ordered mesoporous carbon.

    PubMed

    Wikander, Kjell; Hungria, Ana B; Midgley, Paul A; Palmqvist, Anders E C; Holmberg, Krister; Thomas, John M

    2007-01-01

    Platinum nanoparticles were incorporated within the pore system of ordered mesoporous carbon (OMC) by impregnating the carbon with a water-in-oil (w/o) microemulsion containing dissolved platinum salt followed by reduction of the platinum ions in situ inside the carbon pore system. The procedure provides preparation of metallic nanoparticles from hydrophilic precursors inside the hydrophobic carbon support structure with simultaneous control of the maximum metal particle size. Electron tomography was used to verify the presence of platinum nanoparticles inside the carbon material. PMID:17069827

  4. Selective methylation of kaempferol via benzylation and deacetylation of kaempferol acetates

    PubMed Central

    Mei, Qinggang; Wang, Chun; Yuan, Weicheng

    2015-01-01

    Summary A strategy for selective mono-, di- and tri-O-methylation of kaempferol, predominantly on the basis of selective benzylation and controllable deacetylation of kaempferol acetates, was developed. From the selective deacetylation and benzylation of kaempferol tetraacetate (1), 3,4?,5,-tri-O-acetylkaempferol (2) and 7-O-benzyl-3,4?5,-tri-O-acetylkaempferol (8) were obtained, respectively. By controllable deacetylation and followed selective or direct methylation of these two intermediates, eight O-methylated kaempferols were prepared with 5177% total yields from kaempferol. PMID:25815082

  5. Nanoparticle Incorporation of Melittin Reduces Sperm and Vaginal Epithelium Cytotoxicity

    PubMed Central

    Jallouk, Andrew P.; Moley, Kelle H.; Omurtag, Kenan; Hu, Grace; Lanza, Gregory M.; Wickline, Samuel A.; Hood, Joshua L.

    2014-01-01

    Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free melittin is limited by its cytotoxicity, incorporation of melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing melittin at concentrations <10 M inhibit HIV infectivity in vitro. In the current study, we assessed the impact of blank and melittin-containing perfluorocarbon nanoparticles on sperm motility and the viability of both sperm and vaginal epithelial cells. We found that free melittin was toxic to sperm and vaginal epithelium at concentrations greater than 2 M (p<0.001). However, melittin nanoparticles were not cytotoxic to sperm (p?=?0.42) or vaginal epithelium (p?=?0.48) at an equivalent melittin concentration of 10 M. Thus, nanoparticle formulation of melittin reduced melittin cytotoxicity fivefold and prevented melittin toxicity at concentrations previously shown to inhibit HIV infectivity. Melittin nanoparticles were toxic to vaginal epithelium at equivalent melittin concentrations ?20 M (p<0.001) and were toxic to sperm at equivalent melittin concentrations ?40 M (p<0.001). Sperm cytotoxicity was enhanced by targeting of the nanoparticles to the sperm surface antigen sperm adhesion molecule 1. While further testing is needed to determine the extent of cytotoxicity in a more physiologically relevant model system, these results suggest that melittin-containing nanoparticles could form the basis of a virucide that is not toxic to sperm and vaginal epithelium. This virucide would be beneficial for HIV serodiscordant couples seeking to achieve natural pregnancy. PMID:24748389

  6. A review on the dietary flavonoid kaempferol.

    PubMed

    Calderón-Montaño, J M; Burgos-Morón, E; Pérez-Guerrero, C; López-Lázaro, M

    2011-04-01

    Epidemiological studies have revealed that a diet rich in plant-derived foods has a protective effect on human health. Identifying bioactive dietary constituents is an active area of scientific investigation that may lead to new drug discovery. Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g. tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries and grapes) and in plants or botanical products commonly used in traditional medicine (e.g. Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Some epidemiological studies have found a positive association between the consumption of foods containing kaempferol and a reduced risk of developing several disorders such as cancer and cardiovascular diseases. Numerous preclinical studies have shown that kaempferol and some glycosides of kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, anti-osteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic and antiallergic activities. In this article, the distribution of kaempferol in the plant kingdom and its pharmacological properties are reviewed. The pharmacokinetics (e.g. oral bioavailability, metabolism, plasma levels) and safety of kaempferol are also analyzed. This information may help understand the health benefits of kaempferol-containing plants and may contribute to develop this flavonoid as a possible agent for the prevention and treatment of some diseases. PMID:21428901

  7. Kaempferol inhibits thrombosis and platelet activation.

    PubMed

    Choi, Jun-Hui; Park, Se-Eun; Kim, Sung-Jun; Kim, Seung

    2015-08-01

    The objectives of the present study were to investigate whether kaempferol affects pro-coagulant proteinase activity, fibrin clot formation, blood clot and thrombin (or collagen/epinephrine)-stimulated platelet activation, thrombosis, and coagulation in ICR (Imprinting Control Region) mice and SD (Sprague-Dawley) rats. Kaempferol significantly inhibited the enzymatic activities of thrombin and FXa by 68 1.6% and 52 2.4%, respectively. Kaempferol also inhibited fibrin polymer formation in turbidity. Microscopic analysis was performed using a fluorescent conjugate. Kaempferol completely attenuated phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38, c-Jun N-terminal kinase (JNK) 1/2, and phosphoinositide 3-kinase (PI3K)/PKB (AKT) in thrombin-stimulated platelets and delayed aggregation time (clotting) by 34.6% in an assay of collagen/epinephrine-stimulated platelet activation. Moreover, kaempferol protected against thrombosis development in 3 animal models, including collagen/epinephrine- and thrombin-induced acute thromboembolism models and an FeCl3-induced carotid arterial thrombus model. The ex vivo anticoagulant effect of kaempferol was further confirmed in ICR mice. This study demonstrated that kaempferol may be clinically useful due to its ability to reduce or prevent thrombotic challenge. PMID:26073152

  8. Functionalization of medical cotton by direct incorporation of silver nanoparticles.

    PubMed

    Emam, Hossam E; Saleh, N H; Nagy, Khaled S; Zahran, M K

    2015-07-01

    Medical cotton is usually used to clean skin, pack wounds and in other surgical tasks. Such important usages make imparting the antibacterial property to medical cotton is so essential research. The current research focuses on functionalization of medical cotton by direct incorporation of silver nanoparticles (AgNPs) in two-step process namely, pre-alkalization followed by sorption. Decorative color and antibacterial action were accomplished for medical cotton after in situ incorporation of AgNPs without using any other external reducing agent. AgNPs were produced due to the reduction action of alcoholic and aldehydic groups of cotton's skeletal blocks. Cotton fibers were acquired a decorative color attributed to surface plasmon resonance of AgNPs. The treated cotton was characterized by using electron microscope. Results showed that Ag(0) with size distribution of 0-160 nm was formed in the cotton fibers and their size majority (70%) was less than 80 nm. The reduction of Ag(+) to Ag(0) was confirmed by measuring the carboxylic and aldehydic contents. The treated cotton exhibited excellent antibacterial action at low silver contents. The absorbency of cotton was not affected by treatment. The produced medical cotton could be used to safe cleaning of wounds without getting any microbial infections. PMID:25907009

  9. Kaempferol and inflammation: From chemistry to medicine.

    PubMed

    Devi, Kasi Pandima; Malar, Dicson Sheeja; Nabavi, Seyed Fazel; Sureda, Antoni; Xiao, Jianbo; Nabavi, Seyed Mohammad; Daglia, Maria

    2015-09-01

    Inflammation is an important process of human healing response, wherein the tissues respond to injuries induced by many agents including pathogens. It is characterized by pain, redness and heat in the injured tissues. Chronic inflammation seems to be associated with different types of diseases such as arthritis, allergies, atherosclerosis, and even cancer. In recent years natural product based drugs are considered as the novel therapeutic strategy for prevention and treatment of inflammatory diseases. Among the different types of phyto-constituents present in natural products, flavonoids which occur in many vegetable foods and herbal medicines are considered as the most active constituent, which has the potency to ameliorate inflammation under both in vitro and in vivo conditions. Kaempferol is a natural flavonol present in different plant species, which has been described to possess potent anti-inflammatory properties. Despite the voluminous literature on the anti-inflammatory effects of kaempferol, only very limited review articles has been published on this topic. Hence the present review is aimed to provide a critical overview on the anti-inflammatory effects and the mechanisms of action of kaempferol, based on the current scientific literature. In addition, emphasis is also given on the chemistry, natural sources, bioavailability and toxicity of kaempferol. PMID:25982933

  10. Directly patternable SnO{sub 2} thin films incorporating Pt nanoparticles

    SciTech Connect

    Kim, Hyuncheol; Choi, Yong-June; Kang, Kyung-Mun; Park, Hyung-Ho

    2014-04-01

    Highlights: • Direct-patterning of SnO{sub 2} films incorporated with Pt nanoparticles. • Pt incorporated SnO{sub 2} thin films by using photochemical solution deposition. • Reduction catalytic behavior of Pt nanoparticles. • Progress reduction of SnO{sub 2} with increasing amount of Pt nanoparticles. • Enhanced electrical conductivity of SnO{sub 2} films with Pt nanoparticles incorporation. - Abstract: Direct-patterning of SnO{sub 2} films incorporating Pt nanoparticles was performed by using a photochemical solution deposition without a photoresist or dry etching. Incorporating Pt nanoparticles into these films had a slight effect on their crystallinity and almost no effect on their transmittance. The inclusion of Pt nanoparticles enhanced the electrical conductivity of the SnO{sub 2} thin films compared to their pristine forms. The chemical bonding state of the films was analyzed by X-ray photoelectron spectroscopy to investigate the effect of the Pt nanoparticles on the carrier concentration in the film. It was concluded that the reduction of SnO{sub 2} thin films by Pt nanoparticles progressed as a result of the presence of the Pt nanoparticles, causing an oxygen deficiency to develop in SnO{sub 2} and thereby influencing the carrier concentration of the film.

  11. Cisplatin-incorporated nanoparticles of poly(acrylic acid-co-methyl methacrylate) copolymer

    PubMed Central

    Lee, Kyung Dong; Jeong, Young-Il; Kim, Da Hye; Lim, Gyun-Taek; Choi, Ki-Choon

    2013-01-01

    Background Although cisplatin is extensively used in the clinical field, its intrinsic toxicity limits its clinical use. We investigated nanoparticle formations of poly(acrylic acid-co-methyl methacrylate) (PAA-MMA) incorporating cisplatin and their antitumor activity in vitro and in vivo. Methods Cisplatin-incorporated nanoparticles were prepared through the ion-complex formation between acrylic acid and cisplatin. The anticancer activity of cisplatin-incorporated nanoparticles was assessed with CT26 colorectal carcinoma cells. Results Cisplatin-incorporated nanoparticles have small particle sizes of less than 200 nm with spherical shapes. Drug content was increased according to the increase of the feeding amount of cisplatin and acrylic acid content in the copolymer. The higher acrylic acid content in the copolymer induced increase of particle size and decrease of zeta potential. Cisplatin-incorporated nanoparticles showed a similar growth-inhibitory effect against CT26 tumor cells in vitro. However, cisplatin-incorporated nanoparticles showed improved antitumor activity against an animal tumor xenograft model. Conclusion We suggest that PAA-MMA nanoparticles incorporating cisplatin are promising carriers for an antitumor drug-delivery system. PMID:23966778

  12. Peracylated Glucosyl Kaempferols from Pasania dodonfifolia Leaf.

    PubMed

    Chang, Chi-Chih; Lee, Shoei-Sheng

    2015-08-01

    Phytochemical investigation of the ethanolic extract of Pasania dodoniifolia leaf led to the isolation of four kaempferol 3-0-peracylated glucosides (1-4), together with four flavonoid glucosides (5-8), epicatechin (9), and (7S, 7'S, 8R, 8'R)-icariol A2 (10). Of these, kaempferol-3-O-(3",4"-di-O-acetyl-2"-O-(Z)-p- coumaroyl)-6"-O-(E)-p-coumaroyl)-beta-glucopyranoside (3) and 3-O-(3",4"-di-O-acetyl-2",6"-di-O-(Z)-p-coumaroyl)-beta-glucopyranoside (4) are new and their structures were elucidated by 2D NMR spectroscopic analyses and MS data. PMID:26434120

  13. Chemical Dynamics in Energetic Materials Incorporating Aluminum Nanoparticles

    NASA Astrophysics Data System (ADS)

    Lewis, William K.; Harruff, Barbara A.; Fernando, K. A. Shiral; Smith, Marcus J.; Guliants, Elena A.; Bunker, Christopher E.

    2010-06-01

    Aluminum nanoparticles are widely considered attractive as fuels due to the high heat of reaction associated with their oxidation, and the potential for fast reaction due to their small size. However, the reaction dynamics can also be strongly influenced by the passivation layer that coats the reactive metal surface. Typically, this takes the form of a naturally-occurring oxide shell on the nanoparticle, but other passivation schemes are now available. We have recently developed a sonochemical synthesis procedure to produce aluminum nanoparticles capped with oleic acid. These nanoparticles have an aluminum metal core, some organic-provided oxide, and an organic shell. To investigate the effect of the passivation method on the chemical dynamics in energetic materials, we have studied samples consisting of a mixture of a metal nanoparticle fuel and an ammonium nitrate or ammonium perchlorate oxidizer. The metal fuel is either commercially available oxide-coated aluminum nanoparticles, or the oleic acid-capped nanoparticles. The energetic samples are ignited with an IR laser pulse. Following ignition, the chemical dynamics are studied using visible emission spectroscopy and mass spectrometry. Preliminary results suggest that our Al-oleic acid nanoparticles are able to react more rapidly than those that are conventionally passivated with a naturally-occurring oxide shell. K. A. S. Fernando, M. J. Smith, B. A. Harruff, W. K. Lewis, E. A. Guliants and C. E. Bunker J. Phys. Chem. C, 113, 500 (2009).

  14. Curcumin-incorporated albumin nanoparticles and its tumor image.

    PubMed

    Gong, Guangming; Pan, Qinqin; Wang, Kaikai; Wu, Rongchun; Sun, Yong; Lu, Ying

    2015-01-30

    Albumin is an ideal carrier for hydrophobic drugs. This paper reports a facile route to develop human serum albumin (HSA)-curcumin (CCM) nanoparticles, in which β-mercaptoethanol (β-ME) acted as an inducer and CCM acted as a bridge. Fluorescence quenching and conformational changes in HSA-CCM nanoparticles occurred during assembly. Disulfide bonds and hydrophobic interactions may play a key role in assembly. HSA-CCM nanoparticles were about 130 nm in size, and the solubility of CCM increased by more than 500 times. The HSA-CCM nanoparticles could accumulate at the cytoplasm of tumor cells and target the tumor tissues. Therefore, HSA nanoparticles fabricated by β-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes. PMID:25558927

  15. Curcumin-incorporated albumin nanoparticles and its tumor image

    NASA Astrophysics Data System (ADS)

    Gong, Guangming; Pan, Qinqin; Wang, Kaikai; Wu, Rongchun; Sun, Yong; Lu, Ying

    2015-01-01

    Albumin is an ideal carrier for hydrophobic drugs. This paper reports a facile route to develop human serum albumin (HSA)-curcumin (CCM) nanoparticles, in which β-mercaptoethanol (β-ME) acted as an inducer and CCM acted as a bridge. Fluorescence quenching and conformational changes in HSA-CCM nanoparticles occurred during assembly. Disulfide bonds and hydrophobic interactions may play a key role in assembly. HSA-CCM nanoparticles were about 130 nm in size, and the solubility of CCM increased by more than 500 times. The HSA-CCM nanoparticles could accumulate at the cytoplasm of tumor cells and target the tumor tissues. Therefore, HSA nanoparticles fabricated by β-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes.

  16. Incorporation of magnetite nanoparticle clusters in fluorescent silica nanoparticles for high-performance brain tumor delineation

    NASA Astrophysics Data System (ADS)

    Wan, Jiaqi; Meng, Xiangxi; Liu, Enzhong; Chen, Kezheng

    2010-06-01

    Bifunctional nanoprobes with both magnetic and optical contrast have been developed for ultra-sensitive brain tumor imaging at the cellular level. The nanoprobes were synthesized by simultaneously incorporating a magnetite nanoparticle cluster and fluorescence dyes into silica encapsulation by a sol-gel approach under ultrasonic treatment. The nanoprobes maintain superparamagnetic behavior at room temperature and possess enhanced transverse relaxivity and good photostability. As a glioma targeting ligand, chlorotoxin was covalently bonded to the surface of the nanoprobes. In vitro cellular uptake assays demonstrated that the nanoprobes were highly specific, taken up by human U251-MG glioma cells via receptor-mediated endocytosis. The labeled glioma cells were readily detectable by both MR imager and confocal laser scanning microscopy.

  17. Hybrid organic-inorganic monolithic enzymatic reactor with SBA-15 nanoparticles incorporated.

    PubMed

    Zhang, Zhaodi; Zhang, Lingyi; Zhang, Chenggong; Zhang, Weibing

    2014-02-01

    A novel enzymatic reactor was prepared by incorporating SBA-15 nanoparticles into hybrid organic-inorganic monolith and immobilizing trypsin with glutaraldehyde as bridging reagent. Preparation and operation conditions including nanoparticles percentage and residence time were optimized to improve the digestion efficiency. The digestion products were characterized by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) with sequence coverage of 50%, 93% and 71% for bovine serum albumin, myoglobin and cytochrome C, while consuming only about 19s in dynamic mode. Compared with enzymatic reactor without nanoparticles incorporated, the enzymatic reactor with SBA-15 nanoparticles embedded achieved higher digestion efficiency by introducing more trypsin, which was originated from combination of SBA-15 nanoparticles and hybrid organic-inorganic monolith. PMID:24401445

  18. Incorporation of Metallic Nanoparticles into Conducting Polymer Actuator Films

    NASA Astrophysics Data System (ADS)

    Costa, Alexsandro Santos; Li, Kwong-Chi; Kilmartin, Paul A.; Travas-Sejdic, Jadranka

    2009-07-01

    Nanocomposites of conducting polymer films (CP) with metal nanoparticles have been prepared. Electropolymerization of pyrrole on stainless steel electrodes was undertaken galvanostatically until the thickness of the polypyrrole (PPy) film reached around 7.5 ?m, which is suitable for the future application of these films in micropumps and microvalves. Subsequently platinum nanoparticles were deposited from a solution of a platinum precursor (K2PtCl6) onto the PPy coated stainless steel electrodes by applying a potential of -0.1 V for between 3 and 15 s. The length of the deposition time led to significant differences in the morphology and size of the particles obtained. The actuation of the free standing films was studied by electrochemomechanical deformation measurements (ECMD) on strips of films cycled in NaPF6. Depending upon the test conditions, the strain rate and ultimate strain of films containing Pt nanoparticles could be increased by a factor of 2 or more compared to those of pristine PPy films.

  19. Electrospun Polycaprolactone Membrane Incorporated with Biosynthesized Silver Nanoparticles as Effective Wound Dressing Material.

    PubMed

    Thomas, Roshmi; Soumya, K R; Mathew, Jyothis; Radhakrishnan, E K

    2015-08-01

    Biosynthesized silver nanoparticles (AgNPs) incorporated polycaprolactone (PCL) nanomembrane was prepared by electrospinning as a cost-effective nanocomposite for application as an antimicrobial agent against wound infection. The nanocomposite membrane was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis and Scanning Electron microscopy (SEM). The hydrophilicity analysis of electrospun membranes as evaluated by water contact angle measurement showed the change of hydrophobicity of PCL to hydrophilic upon incorporation of silver nanoparticles. Better mechanical properties were also observed for PCL membrane due to the incorporation of silver nanoparticles and are highly supportive to explore its biomedical applications. Further antibacterial analysis of silver nanoparticle-incorporated PCL membrane against common wound pathogens coagulase-negative Staphylococcus epidermidis and Staphylococcus haemolyticus showed remarkable activity. As biosynthesized AgNPs are least explored for clinical applications, the current study is a promising cost-effective method to explore the development of silver nanoparticle-based electrospun nanocomposite to resist wound-associated infection. PMID:26113218

  20. Optofluidics incorporating actively controlled micro- and nano-particles

    PubMed Central

    Kayani, Aminuddin A.; Khoshmanesh, Khashayar; Ward, Stephanie A.; Mitchell, Arnan; Kalantar-zadeh, Kourosh

    2012-01-01

    The advent of optofluidic systems incorporating suspended particles has resulted in the emergence of novel applications. Such systems operate based on the fact that suspended particles can be manipulated using well-appointed active forces, and their motions, locations and local concentrations can be controlled. These forces can be exerted on both individual and clusters of particles. Having the capability to manipulate suspended particles gives users the ability for tuning the physical and, to some extent, the chemical properties of the suspension media, which addresses the needs of various advanced optofluidic systems. Additionally, the incorporation of particles results in the realization of novel optofluidic solutions used for creating optical components and sensing platforms. In this review, we present different types of active forces that are used for particle manipulations and the resulting optofluidic systems incorporating them. These systems include optical components, optofluidic detection and analysis platforms, plasmonics and Raman systems, thermal and energy related systems, and platforms specifically incorporating biological particles. We conclude the review with a discussion of future perspectives, which are expected to further advance this rapidly growing field. PMID:23864925

  1. Optofluidics incorporating actively controlled micro- and nano-particles.

    PubMed

    Kayani, Aminuddin A; Khoshmanesh, Khashayar; Ward, Stephanie A; Mitchell, Arnan; Kalantar-Zadeh, Kourosh

    2012-09-01

    The advent of optofluidic systems incorporating suspended particles has resulted in the emergence of novel applications. Such systems operate based on the fact that suspended particles can be manipulated using well-appointed active forces, and their motions, locations and local concentrations can be controlled. These forces can be exerted on both individual and clusters of particles. Having the capability to manipulate suspended particles gives users the ability for tuning the physical and, to some extent, the chemical properties of the suspension media, which addresses the needs of various advanced optofluidic systems. Additionally, the incorporation of particles results in the realization of novel optofluidic solutions used for creating optical components and sensing platforms. In this review, we present different types of active forces that are used for particle manipulations and the resulting optofluidic systems incorporating them. These systems include optical components, optofluidic detection and analysis platforms, plasmonics and Raman systems, thermal and energy related systems, and platforms specifically incorporating biological particles. We conclude the review with a discussion of future perspectives, which are expected to further advance this rapidly growing field. PMID:23864925

  2. Superparamagnetic iron oxide nanoparticles incorporated into silica nanoparticles by inelastic collision via ultrasonic field: Role of colloidal stability

    NASA Astrophysics Data System (ADS)

    Sodipo, Bashiru Kayode; Azlan, Abdul Aziz

    2015-04-01

    Superparamagnetic iron oxide nanoparticles (SPION)/Silica composite nanoparticles were prepared by ultrasonically irradiating colloidal suspension of silica and SPION mixture. Both silica and SPION were synthesized independently via co-precipitation and sol-gel method, respectively. Their mixtures were sonicated at different pH between 3 and 5. Electrophoresis measurement and other physicochemical analyses of the products demonstrate that at lower pH SPION was found incorporated into the silica. However, at pH greater than 4, SPION was unstable and unable to withstand the turbulence flow and shock wave from the ultrasonic field. Results suggest that the formation of the SPION/silica composite nanoparticles is strongly related to the inelastic collision induced by ultrasonic irradiation. More so, the formation the composite nanoparticles via the ultrasonic field are dependent on the zeta potential and colloidal stability of the particles.

  3. Superparamagnetic iron oxide nanoparticles incorporated into silica nanoparticles by inelastic collision via ultrasonic field: Role of colloidal stability

    SciTech Connect

    Sodipo, Bashiru Kayode; Azlan, Abdul Aziz

    2015-04-24

    Superparamagnetic iron oxide nanoparticles (SPION)/Silica composite nanoparticles were prepared by ultrasonically irradiating colloidal suspension of silica and SPION mixture. Both silica and SPION were synthesized independently via co-precipitation and sol-gel method, respectively. Their mixtures were sonicated at different pH between 3 and 5. Electrophoresis measurement and other physicochemical analyses of the products demonstrate that at lower pH SPION was found incorporated into the silica. However, at pH greater than 4, SPION was unstable and unable to withstand the turbulence flow and shock wave from the ultrasonic field. Results suggest that the formation of the SPION/silica composite nanoparticles is strongly related to the inelastic collision induced by ultrasonic irradiation. More so, the formation the composite nanoparticles via the ultrasonic field are dependent on the zeta potential and colloidal stability of the particles.

  4. Development and characterization of solid oral dosage form incorporating candesartan nanoparticles.

    PubMed

    Nekkanti, Vijaykumar; Pillai, Raviraj; Venkateshwarlu, Vobalaboina; Harisudhan, T

    2009-01-01

    Sparingly water-soluble drugs such as candesartan cilexetil offer challenges in developing a drug product with adequate bioavailability. The objective of the present study was to develop a tablet dosage form of candesartan cilexetil incorporating drug nanoparticles to increase its saturation solubility and dissolution rate for enhancing bioavailability while reducing variability in systemic exposure. The bioavailability of candesartan cilexetil is dissolution limited following oral administration. To enhance bioavailability and overcome variability in systemic exposure, a nanoparticle formulation of candesartan cilexetil was developed. Candesartan cilexetil nanoparticles were prepared using a wet bead milling technique. The milled nanosuspension was converted into solid intermediate using a spray drying process. The nanosuspensions were characterized for particle size before and after spray drying. The spray dried nanoparticles were blended with excipients for tableting. The saturation solubility and dissolution characteristics of the nanoparticle formulation were investigated and compared with commercial candesartan cilexetil formulation. The drug nanoparticles were evaluated for solid-state transitions before and after milling. This study demonstrated that tablet formulation incorporating drug nanoparticles showed significantly faster rate of drug dissolution in a discriminating dissolution medium as compared to commercially available tablet formulation. Systemic exposure studies in rats indicated a significant increase in the rate and extent of drug absorption. PMID:19235553

  5. E-beam crosslinked, biocompatible functional hydrogels incorporating polyaniline nanoparticles

    NASA Astrophysics Data System (ADS)

    Dispenza, C.; Sabatino, M.-A.; Niconov, A.; Chmielewska, D.; Spadaro, G.

    2012-09-01

    PANI aqueous nanocolloids in their acid-doped, inherently conductive form were synthesised by means of suitable water soluble polymers used as stabilisers. In particular, poly(vinyl alcohol) (PVA) or chitosan (CT) was used to stabilise PANI nanoparticles, thus preventing PANI precipitation during synthesis and upon storage. Subsequently, e-beam irradiation of the PANI dispersions has been performed with a 12 MeV Linac accelerator. PVA-PANI nanocolloid has been transformed into a PVA-PANI hydrogel nanocomposite by radiation induced crosslinking of PVA. CT-PANI nanoparticles dispersion, in turn, was added to PVA to obtain wall-to-wall gels, as chitosan mainly undergoes chain scission under the chosen irradiation conditions. While the obtainment of uniform PANI particle size distribution was preliminarily ascertained with laser light scattering and TEM microscopy, the typical porous structure of PVA-based freeze dried hydrogels was observed with SEM microscopy for the hydrogel nanocomposites. UV-visible absorption spectroscopy demonstrates that the characteristic, pH-dependent and reversible optical absorption properties of PANI are conferred to the otherwise optically transparent PVA hydrogels. Selected formulations have been also subjected to MTT assays to prove the absence of cytotoxicity.

  6. A hybrid twin screw extrusion/electrospinning method to process nanoparticle-incorporated electrospun nanofibres

    NASA Astrophysics Data System (ADS)

    Erisken, Cevat; Kalyon, Dilhan M.; Wang, Hongjun

    2008-04-01

    A new hybrid methodology that fully integrates the processing capabilities of the twin screw extrusion process (conveying solids, melting, dispersive and distributive mixing, pressurization, temperature profiling, devolatilization) with electrospinning is described. The hybrid process is especially suited to the dispersion of nanoparticles into polymeric binders and the generation of nanoparticle-incorporated fibres and nanofibres. The new technology base is demonstrated with the dispersion of ?-tricalcium phosphate (?-TCP) nanoparticles into poly(?-caprolactone) (PCL) to generate biodegradable non-woven meshes that can be targeted as scaffolds for tissue engineering applications. The new hybrid method yielded fibre diameters in the range of 200-2000 nm for both PCL and ?-TCP/PCL (35% by weight) composite scaffolds. The degree of crystallinity of polycaprolactone meshes could be manipulated in the 35.1-41% range, using the voltage strength as a parameter. The electrospinning process, integrated with dispersive kneading disc elements, facilitated the decrease of the cluster sizes and allowed the continuous compounding of the nanoparticles into the biodegradable polymer prior to electrospinning. Thermogravimetric analysis (TGA) of the non-woven meshes validated the continuous incorporation of 35 1.5% (by weight) ?-TCP nanoparticles for a targeted concentration of 35%. Uniaxial tensile testing of the meshes with and without the nanoparticles indicated that the ultimate tensile strength at break of the meshes increased from 0.47 0.04 to 0.79 0.08 MPa upon the incorporation of the ?-TCP nanoparticles. This demonstration study suggests that the new technology base is particularly suitable for the concomitant dispersion and electrospinning of nanoparticles in the generation of myriad types of functional nanofibres.

  7. Kaempferol inhibits Entamoeba histolytica growth by altering cytoskeletal functions.

    PubMed

    Bolaos, Vernica; Daz-Martnez, Alfredo; Soto, Jacqueline; Marchat, Laurence A; Sanchez-Monroy, Virginia; Ramrez-Moreno, Esther

    2015-11-01

    The flavonoid kaempferol obtained from Helianthemum glomeratum, an endemic Mexican medicinal herb used to treat gastrointestinal disorders, has been shown to inhibit growth of Entamoeba histolytica trophozoites in vitro; however, the mechanisms associated with this activity have not been documented. Several works reported that kaempferol affects cytoskeleton in mammalian cells. In order to gain insights into the action mechanisms involved in the anti-amoebic effect of kaempferol, here we evaluated the effect of this compound on the pathogenic events driven by the cytoskeleton during E. histolytica infection. We also carried out a two dimensional gel-based proteomic analysis to evidence modulated proteins that could explain the phenotypical changes observed in trophozoites. Our results showed that kaempferol produces a dose-dependent effect on trophozoites growth and viability with optimal concentration being 27.7?M. Kaempferol also decreased adhesion, it increased migration and phagocytic activity, but it did not affect erythrocyte binding nor cytolytic capacity of E. histolytica. Congruently, proteomic analysis revealed that the cytoskeleton proteins actin, myosin II heavy chain and cortexillin II were up-regulated in response to kaempferol treatment. In conclusion, kaempferol anti-amoebic effects were associated with deregulation of proteins related with cytoskeleton, which altered invasion mechanisms. PMID:26620675

  8. Nanocomposite Materials - Ferroelectric Nanoparticles Incorporated into Porous Matrix

    NASA Astrophysics Data System (ADS)

    Rysiakiewicz-Pasek, E.; Poprawski, R.; Ci?man, A.; Sieradzki, A.

    The aim of this work is to develop a technique of introducing selected ferroelectric materials (TGS, NaNO2, NaNO3, KNO3, ADP and KDP) into porous glasses with various average pore dimensions. The major efforts have been focused on the investigations of the influence of the pore size on physical properties and phase transition of nanocrystals embedded into porous matrix with different methods. The ferroelectrics have been introduced into porous glasses from the melt and a water solution. The results of electrical (dielectric, pyroelectric) and thermal (dilatometric and calorimetric) measurements have shown that the observed sequences of phase transitions in ferroelectric materials embedded into the porous glasses are similar to that in bulk crystals. The relationship between phase transition and melt temperatures versus average values of pore dimensions has been determined. The experimentally observed shift of phase transition temperatures is the superposition of the size effect and pressure effect created by the difference of thermal expansion coefficients of ferroelectrics nanoparticles and glass matrix.

  9. Electrospun PCL membranes incorporated with biosynthesized silver nanoparticles as antibacterial wound dressings

    NASA Astrophysics Data System (ADS)

    Aggarwal, Sneha; Rajput, Yudhishthir Singh; Singh, Gulab; Sharma, Rajan

    2015-04-01

    An open wound is highly prone to bacterial colonization and infection. Bacterial barrier property is an important factor that determines the success of a wound coverage material. Apart from the bacterial barrier property, presence of antibacterial agents can successfully eliminate the invasion and colonization of pathogen in the wound. Silver nanoparticles are well-known antimicrobial agents against a wide range of microorganisms. Biosynthesized silver nanoparticles are more acceptable for medical applications due to superior biocompatibility than chemically synthesized ones. Presence of biomolecules on biosynthesized silver nanoparticles enhances its therapeutic efficiency. Polycaprolactone (PCL) is a well-known material for biomedical applications including wound dressings. Electrospinning is an excellent technique for the fabrication of thin membranes for wound coverage applications with barrier property against microbes. In this paper, we report the fabrication and characterization of electrospun PCL membranes incorporated with biosynthesized silver nanoparticles for wound dressing applications.

  10. Electrospun PCL membranes incorporated with biosynthesized silver nanoparticles as antibacterial wound dressings

    NASA Astrophysics Data System (ADS)

    Augustine, Robin; Kalarikkal, Nandakumar; Thomas, Sabu

    2016-03-01

    An open wound is highly prone to bacterial colonization and infection. Bacterial barrier property is an important factor that determines the success of a wound coverage material. Apart from the bacterial barrier property, presence of antibacterial agents can successfully eliminate the invasion and colonization of pathogen in the wound. Silver nanoparticles are well-known antimicrobial agents against a wide range of microorganisms. Biosynthesized silver nanoparticles are more acceptable for medical applications due to superior biocompatibility than chemically synthesized ones. Presence of biomolecules on biosynthesized silver nanoparticles enhances its therapeutic efficiency. Polycaprolactone (PCL) is a well-known material for biomedical applications including wound dressings. Electrospinning is an excellent technique for the fabrication of thin membranes for wound coverage applications with barrier property against microbes. In this paper, we report the fabrication and characterization of electrospun PCL membranes incorporated with biosynthesized silver nanoparticles for wound dressing applications.

  11. Drug incorporation and release of water soluble drugs from novel functionalized poly(glycerol adipate) nanoparticles.

    PubMed

    Puri, Sanyogita; Kallinteri, Paraskevi; Higgins, Sean; Hutcheon, Gillian A; Garnett, Martin C

    2008-01-01

    We have previously demonstrated the ability of poly(glycerol adipate) backbone (PGA) and PGA polymer backbone substituted with varying amounts of pendant C(18) chain length acyl groups to yield Dexamethasone phosphate DXMP loaded nanoparticles. The aim of this study was to obtain a deeper understanding of the underlying principles responsible for good drug incorporation and controlled release of drugs from poly (glycerol adipate) (PGA) nanoparticles. We compared the incorporation of the water soluble drugs DXMP and Cytosine arabinoside (CYT-ARA) in both unmodified and substituted PGA polymers. We investigated the effect of change in acyl group chain length and the degree of substitution on the physicochemical properties, drug loading and release of DXMP and CYT-ARA. Nanoparticles were prepared by the interfacial deposition technique and the simultaneous emulsification method. Amongst the nanoparticles prepared using acylated polymers with varying chain lengths (C(2) to C(10)) for DXMP incorporation, polymers with acyl group chain lengths containing 8 carbon atoms (C(8)) showed maximum drug incorporation. Amongst the C(8) series, polymers with 100% acylation provided both good drug incorporation and a controlled release for DXMP while for CYT-ARA it was the unsubstituted polymer backbone that had maximum drug loading and slower release. A number of inter-related factors are responsible for producing particles with particular size, zeta potential, drug loading and release characteristics. Drug loading and release from nanoparticles are primarily influenced by the nature of interactions between the drug and polymers which in turn depend upon the type of drug used and the physical chemistry of the polymer. PMID:18035443

  12. Antitumor activity of sorafenib-incorporated nanoparticles of dextran/poly(dl-lactide- co-glycolide) block copolymer

    NASA Astrophysics Data System (ADS)

    Kim, Do Hyung; Kim, Min-Dae; Choi, Cheol-Woong; Chung, Chung-Wook; Ha, Seung Hee; Kim, Cy Hyun; Shim, Yong-Ho; Jeong, Young-Il; Kang, Dae Hwan

    2012-01-01

    Sorafenib-incoporated nanoparticles were prepared using a block copolymer that is composed of dextran and poly( DL-lactide- co-glycolide) [Dex bLG] for antitumor drug delivery. Sorafenib-incorporated nanoparticles were prepared by a nanoprecipitation-dialysis method. Sorafenib-incorporated Dex bLG nanoparticles were uniformly distributed in an aqueous solution regardless of the content of sorafenib. Transmission electron microscopy of the sorafenib-incorporated Dex bLG nanoparticles revealed a spherical shape with a diameter < 300 nm. Sorafenib-incorporated Dex bLG nanoparticles at a polymer/drug weight ratio of 40:5 showed a relatively uniform size and morphology. Higher initial drug feeding was associated with increased drug content in nanoparticles and in nanoparticle size. A drug release study revealed a decreased drug release rate with increasing drug content. In an in vitro anti-proliferation assay using human cholangiocarcinoma cells, sorafenib-incorporated Dex bLG nanoparticles showed a similar antitumor activity as sorafenib. Sorafenib-incorporated Dex bLG nanoparticles are promising candidates as vehicles for antitumor drug targeting.

  13. Antitumor activity of sorafenib-incorporated nanoparticles of dextran/poly(dl-lactide-co-glycolide) block copolymer

    PubMed Central

    2012-01-01

    Sorafenib-incoporated nanoparticles were prepared using a block copolymer that is composed of dextran and poly(DL-lactide-co-glycolide) [DexbLG] for antitumor drug delivery. Sorafenib-incorporated nanoparticles were prepared by a nanoprecipitation-dialysis method. Sorafenib-incorporated DexbLG nanoparticles were uniformly distributed in an aqueous solution regardless of the content of sorafenib. Transmission electron microscopy of the sorafenib-incorporated DexbLG nanoparticles revealed a spherical shape with a diameter < 300 nm. Sorafenib-incorporated DexbLG nanoparticles at a polymer/drug weight ratio of 40:5 showed a relatively uniform size and morphology. Higher initial drug feeding was associated with increased drug content in nanoparticles and in nanoparticle size. A drug release study revealed a decreased drug release rate with increasing drug content. In an in vitro anti-proliferation assay using human cholangiocarcinoma cells, sorafenib-incorporated DexbLG nanoparticles showed a similar antitumor activity as sorafenib. Sorafenib-incorporated DexbLG nanoparticles are promising candidates as vehicles for antitumor drug targeting. PMID:22283905

  14. Preparation of gelatin films incorporated with tea polyphenol nanoparticles for enhancing controlled-release antioxidant properties.

    PubMed

    Liu, Fei; Antoniou, John; Li, Yue; Yi, Jiang; Yokoyama, Wallace; Ma, Jianguo; Zhong, Fang

    2015-04-22

    Gelatin films incorporated with chitosan nanoparticles in various free/encapsulated tea polyphenol (TP) ratios were prepared in order to investigate the influence of different ratios on the physicochemical and antioxidant properties of films. The TP-containing nanoparticles were prepared by cross-linking chitosan hydrochloride (CSH) with sulfobutyl ether-?-cyclodextrin sodium (SBE-?-CD) at three different encapsulation efficiencies (EE; ?50%, ?80%, and ?100%) of TP. The stability of TP-loaded nanoparticles was maintained during the film drying process from the analysis of free TP content in the redissolved film solutions. Composite films showed no significant difference in visual aspects, while the light transmittance (250-550 nm) was decreased with incorporation of TP. Nanoparticles appeared to be homogeneously dispersed within the film matrix by microstructure analysis (SEM and AFM). TP-loaded films had ferric reducing and DPPH radical scavenging power that corresponded to the EEs. Sunflower oil packaged in bags made of gelatin films embedded with nanoparticles of 80% EE showed the best oxidation inhibitory effect, followed by 100% EE, 50% EE, and free TP, over 6 weeks of storage. However, when the gelatin film was placed over the headspace and was not in contact with the oil, the free TP showed the best effect. The results indicate that sustained release of TP in the contacting surface can ensure the protective effects, which vary with free/encapsulated mass ratios, thus improving antioxidant activities instead of increasing the dosage. PMID:25826241

  15. The improvement of characteristics of biodegradable films made from kefiran-whey protein by nanoparticle incorporation.

    PubMed

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

    2014-08-30

    Biodegradable kefiran-whey protein isolate (WPI) nanocomposites were produced using montmorillonite (MMT) and nano-TiO2 as nanoparticles in the percentage of 1, 3, and 5% (w/w) by a casting and solvent-evaporation method. Physical, mechanical, and water-vapor permeability (WVP) properties were determined as a function of nanoparticle concentration. The results revealed that the effect of these nanoparticles was different according to their nature and percentage. The films incorporated with 5% (w/w) MMT showed the highest tensile strength, Young's modulus, puncture strength, and the lowest WVP compared with the control and TiO2 added films. In contrast to MMT, addition of TiO2 nanoparticles due to the plasticizing effect led to a significant change in color and transparency of nanocomposite. Scanning electron microscopy (SEM) observations demonstrated the films' properties in relation to their microstructures. The surface topography results also showed a considerable increase in roughness parameters by incorporating the nanoparticles in kefiran-WPI matrix. PMID:24815408

  16. Preparation and characterization of whey protein film incorporated with TiO2 nanoparticles.

    PubMed

    Zhou, J J; Wang, S Y; Gunasekaran, S

    2009-09-01

    Biodegradable titanium dioxide (TiO(2))/whey protein isolate (WPI) blend films were made by casting denatured WPI film solutions incorporated with TiO(2) nanoparticles. X-ray diffraction, UV-vis spectra, and fluorescence spectra of the films showed the successful incorporation of TiO(2) nanoparticles into the WPI matrix and indicated the interactions between TiO(2) and WPI. Mechanical tests revealed the antiplasticizing effect of TiO(2) nanoparticles on the WPI/TiO(2) film. Small amounts (<1 wt%) of added TiO(2) nanoparticles significantly increase the tensile properties of WPI film, but also decrease the moisture barrier properties. The addition of higher amounts (>1 wt%) of TiO(2) improves moisture barrier properties but lowers the tensile properties of the film. Microstructural evaluation confirmed the aggregation and distribution of TiO(2) nanoparticles within the WPI matrix and validated the results of functional properties of the WPI/TiO(2) film. PMID:19895492

  17. Radiolysis of kaempferol in water/methanol mixtures. Evaluation of antioxidant activity of kaempferol and products formed.

    PubMed

    Marfak, Abdelghafour; Trouillas, Patrick; Allais, Daovy-Paulette; Champavier, Yves; Calliste, Claude-Alain; Duroux, Jean-Luc

    2003-02-26

    Oxidative reaction between hydroxymethyl radical ((*)CH(2)OH) and kaempferol, in methanol and methanol/water mixtures, was studied by gamma-radiolysis using a (60)Co source. Radiolysis was performed with concentrations and doses ranging from 5 x 10(-)(5) M to 5 x 10(-)(3) M and from 0.5 kGy to 14 kGy, respectively. Kaempferol degradation was followed by HPLC. Results showed that (*)CH(2)OH reacts with kaempferol at the 3-OH group and produces two depsides (K1 and K2) and other products including K3. K1, K2, and K3 were identified by NMR, LC-MS, and HRMS. The kaempferol degradation pathway leading to the K1, K2, and K3 formation is proposed. It was observed that the more water concentration in the irradiation medium increases, the more K2 concentration increases. Comprehension of food preservation is not clear because many phenomena occurring during irradiation are not established. Radiolysis of kaempferol in water/methanol mixtures helps to elucidate the phenomenon and it is possible that during the treatment of nutriments by gamma-irradiation, a series of products such as depside K2 could be formed. Antioxidant properties of kaempferol radiolysis products were evaluated according to their capacity to decrease the EPR DPPH (1,1-diphenyl-2-picrylhydrazil) signal and to inhibit superoxide radicals formed by the enzyme reaction "xanthine + xanthine oxidase". PMID:12590467

  18. Mycobased synthesis of silver nanoparticles and their incorporation into sodium alginate films for vegetable and fruit preservation.

    PubMed

    Mohammed Fayaz, A; Balaji, K; Girilal, M; Kalaichelvan, P T; Venkatesan, R

    2009-07-22

    Biosynthesis of silver nanoparticles using Trichoderma viride and their incorporation into sodium alginate for vegetable and fruit preservation has been demonstrated in this study. Aqueous silver (Ag(+)) ions when exposed to the filtrate of T. viride are reduced in solution. These extremely stable silver nanoparticles were characterized by means of UV-vis spectrophotometer, FTIR, TEM, and EDS. The nanoparticles exhibit maximum absorbance at 421 nm in the UV spectrum. The presence of proteins was identified by FTIR. TEM micrograph revealed the formation of polydispersed nanoparticles, and the presence of elemental silver was confirmed by EDS analysis. The silver nanoparticle incorporated sodium alginate thin film shows good antibacterial activity against test strains. This film increases the shelf life of carrot and pear when compared to control with respect to weight loss and soluble protein content. These results show silver nanoparticle incorporated sodium alginate coated vegetables and fruits are suitable for preservation. PMID:19552418

  19. Polymeric systems incorporating plant viral nanoparticles for tailored release of therapeutics.

    PubMed

    Honarbakhsh, Sara; Guenther, Richard H; Willoughby, Julie A; Lommel, Steven A; Pourdeyhimi, Behnam

    2013-07-01

    Therapeutic polylactide (PLA) nanofibrous matrices are fabricated by incorporating plant viral nanoparticles (PVNs) infused with fluorescent agents ethidium bromide (EtBr) and rhodamine (Rho), and cancer therapeutic doxorubicin (Dox). The native virus, Red clover necrotic mosaic virus (RCNMV), reversibly opens and closes upon exposure to the appropriate environmental stimuli. Infusing RCNMV with small molecules allows the incorporation of PVN(Active) into fibrous matrices via two methods: direct processing by in situ electrospinning of a polymer and PVNs solution or immersion of the matrix into a viral nanoparticle solution. Five organic solvents commonly in-use for electrospinning are evaluated for potential negative impact on RCNMV stability. In addition, leakage of rhodamine from the corresponding PVN(Rho) upon solvent exposure is determined. Incorporation of the PVN into the matrices are evaluated via transmission electron, scanning electron and fluorescent microscopies. Finally, the percent cumulative release of doxorubicin from both PLA nanofibers and PLA and polyethylene oxide (PEO) hybrid nanofibers demonstrate tailored release due to the incorporation of PVN(Dox) as compared to the control nanofibers with free Dox. Preliminary kinetic analysis results suggest a two-phase release profile with the first phase following a hindered Fickian transport mechanism for the release of Dox for the polymer-embedded PVNs. In contrast, the nanofiber matrices that incorporate PVNs through the immersion processing method followed a pseudo-first order kinetic transport mechanism. PMID:23335438

  20. Associations between iron oxyhydroxide nanoparticle growth and metal adsorption/structural incorporation

    SciTech Connect

    Kim, C.S.; Lentini, C.J.; Waychunas, G.A.

    2008-09-15

    The interaction of metal ions and oxyanions with nanoscale mineral phases has not yet been extensively studied despite the increased recognition of their prevalence in natural systems as a significant component of geomedia. A combination of macroscopic uptake studies to investigate the adsorption behavior of As(V), Cu(II), Hg(II), and Zn(II) onto nanoparticulate goethite ({alpha}-FeOOH) as a function of aging time at elevated temperature (75 C) and synchrotron-based X-ray studies to track changes in both the sorption mode and the rate of nanoparticle growth reveal the effects that uptake has on particle growth. Metal(loid) species which sorb quickly to the iron oxyhydroxide particles (As(V), Cu(II)) appear to passivate the particle surface, impeding the growth of the nanoparticles with progressive aging; in contrast, species that sorb more slowly (Hg(II), Zn(II)) have considerably less impact on particle growth. Progressive changes in the speciation of these particular metals with time suggest shifts in the mode of metal uptake with time, possibly indicating structural incorporation of the metal(loid) into the nanoparticle; this is supported by the continued increase in uptake concomitant with particle growth, implying that metal species may transform from surface-sorbed species to more structurally incorporated forms. This type of incorporation would have implications for the long-term fate and mobility of metals in contaminated regions, and affect the strategy for potential remediation/modeling efforts.

  1. Ionic liquid pretreatment of poplar wood at room temperature: swelling and incorporation of nanoparticles

    SciTech Connect

    Lucas, Marcel; Macdonald, Brian A; Wagner, Gregory L; Joyce, Steven A; Rector, Kirk D

    2010-01-01

    Lignocellulosic biomass represents a potentially sustainable source of liquid fuels and commodity chemicals. It could satisfy the energy needs for transportation and electricity generation, while contributing substantially to carbon sequestration and limiting the accumulation of greenhouse gases in the atmosphere. Potential feedstocks are abundant and include crops, agricultural wastes, forest products, grasses, and algae. Among those feedstocks, wood is mainly constituted of three components: cellulose, hemicellulose, and lignin. The conversion process of lignocellulosic biomass typically consists of three steps: (1) pretreatment; (2) hydrolysis of cellulose and hemicellulose into fermentable sugars; and (3) fermentation of the sugars into liquid fuels (ethanol) and other commodity chemicals. The pretreatment step is necessary due to the complex structure of the plant cell wall and the chemical resistance of lignin. Most current pretreatments are energy-intensive and/or polluting. So it is imperative to develop new pretreatments that are economically viable and environmentally friendly. Recently, ionic liquids have attracted considerable interest, due to their ability to dissolve biopolymers, such as cellulose, lignin, native switchgrass, and others. Ionic liquids are also considered green solvents, since they have been successfully recycled at high yields for further use with limited efficiency loss. Also, a few microbial cellulases remain active at high ionic liquid concentration. However, all studies on the dissolution of wood in ionic liquids have been conducted so far at high temperatures, typically above 90 C. Development of alternative pretreatments at room temperature is desirable to eliminate the additional energy cost. In this study, thin sections of poplar wood were swollen at room temperature by a 3 h ionic liquid (1-ethyl-3-methylimidazolium acetate or EMIMAc) pretreatment. The pretreated sample was then exposed to an aqueous suspension of nanoparticles that resulted in the sample contraction and the deposition of nanoparticles onto the surface and embedded into the cell wall. To date, both silver and gold particles ranging in size from 40-100 nm have been incorporated into wood. Penetration of gold nanoparticles of 100 nm diameter in the cell walls was best confirmed by near-infrared confocal Raman microscopy, since the deposition of gold nanoparticles induces a significant enhancement of the Raman signal from the wood in their close proximity, an enhancement attributed to the surface-enhanced Raman effect (SERS). After rinsing with water, scanning electron microscopy (SEM) and Raman images of the same areas show that most nanoparticles remained on the pretreated sample. Raman images at different depths reveal that a significant number of nanoparticles were incorporated into the wood sample, at depths up to 4 {micro}m, or 40 times the diameter of the nanoparticles. Control experiments on an untreated wood sample resulted in the deposition of nanoparticles only at the surface and most nanoparticles were removed upon rinsing. This particle incorporation process enables the development of new pretreatments, since the nanoparticles have a high surface-to-volume ratio and could be chemically functionalized. Other potential applications for the incorporated nanoparticles include isotope tracing, catalysis, imaging agents, drug-delivery systems, energy-storage devices, and chemical sensors.

  2. Impact of magnetite nanoparticle incorporation on the eigenfrequencies of nanocomposite microcapsules

    NASA Astrophysics Data System (ADS)

    Glukhova, O. E.; Grishina, O. A.

    2015-03-01

    Modern researches showed that nanocomposite films with magnetite nanoparticle incorporation have good perspectives for applications in electronics to create antireflective coatings and also for biomedical applications to create coatings with remote control of physical properties using alternative magnetic field or microwave radiation, which is very important for fabrication of new generation substrates in tissue engineering and advanced drug delivery systems. In particular, the unique properties of advanced nanocomposite microcapsules allowed developing of the supramolecular system of targeted drug delivery. A study of the behavior of the nanocomposite shell of microcapsules, which consists of alternate layers of negatively charged iron oxide nanoparticles and cationic polyallylamine hydrochloride molecules, was carried out. The aim of the present study was to investigate the effect of the number of nanoparticle layers on magnetic properties of polyelectrolyte/nanoparticles nanocomposite microcapsules prepared via layer-by-layer technique using iron oxide colloids. In result of numerical simulation using ANSYS Workbench software the behavior of the nanocomposite shell of microcapsules depending on the concentration of magnetite particles in it was investigated. Modal and harmonic analysis of behavior of the microcapsules shell was conducted in water at a temperature of 37°. As a result of numerical experiment the eigenfrequencies and mode shape were first time defined for any modifications of the nanocomposite microcapsules. It has been established that the magnetic permeability value depends on the number of iron oxide nanoparticle layers in a nanocomposite microcapsule.

  3. Preparation of polylactide-co-glycolide nanoparticles incorporating celecoxib and their antitumor activity against brain tumor cells

    PubMed Central

    Kim, Tae-Ho; Jeong, Young-Il; Jin, Shu-Guang; Pei, Jian; Jung, Tae-Young; Moon, Kyung-Sub; Kim, In-Young; Kang, Sam-Suk; Jung, Shin

    2011-01-01

    Background Celecoxib, a cyclo-oxygenase (COX)-2 inhibitor, has been reported to mediate growth inhibitory effects and to induce apoptosis in various cancer cell lines. In this study, we examined the potential effects of celecoxib on glioma cell proliferation, migration, and inhibition of COX-2 expression in vitro. Methods Celecoxib was incorporated into poly DL-lactide-co-glycolide (PLGA) nanoparticles for antitumor drug delivery. Results PLGA nanoparticles incorporating celecoxib had spherical shapes and their particle sizes were in the range of 50200 nm. Drug-loading efficiency was not significantly changed according to the solvent used, except for acetone. Celecoxib was released from the PLGA nanoparticles for more than 2 days, and the higher the drug content, the longer the duration of drug release. PLGA nanoparticles incorporating celecoxib showed cytotoxicity against U87MG tumor cells similar to that of celecoxib administered alone. Furthermore, celecoxib did not affect the degree of migration of U87MG cells. PLGA nanoparticles incorporating celecoxib showed dose-dependent cytotoxicity similar to that of celecoxib alone in C6 rat glioma cells. Western blot assay of the C6 cells showed that neither celecoxib alone nor PLGA nanoparticles incorporating celecoxib affected COX-2 expression. Conclusion PLGA nanoparticles incorporating celecoxib had antitumor activity similar to that of celecoxib alone, even though these particles did not affect the degree of migration or COX-2 expression in the tumor cells. PMID:22114493

  4. Effect of silver nanoparticles incorporation on viscoelastic properties of acrylic resin denture base material

    PubMed Central

    Mahross, Hamada Zaki; Baroudi, Kusai

    2015-01-01

    Objective: The objective was to investigate the effect of silver nanoparticles (AgNPs) incorporation on viscoelastic properties of acrylic resin denture base material. Materials and Methods: A total of 20 specimens (60 × 10 × 2 mm) of heat cured acrylic resin were constructed and divided into four groups (five for each), according to the concentration of AgNPs (1%, 2%, and 5% vol.) which incorporated into the liquid of acrylic resin material and one group without additives (control group). The dynamic viscoelastic test for the test specimens was performed using the computerized material testing system. The resulting deflection curves were analyzed by material testing software NEXYGEN MT. Results: The 5% nanoparticles of silver (NAg) had significantly highest mean storage modulus E’ and loss tangent Tan δ values followed by 2% NAg (P < 0.05). For 1% nanosilver incorporation (group B), there were no statistically significant differences in storage modulus E’, lost modulus E” or loss tangent Tan δ with other groups (P > 0.05). Conclusion: The AgNPs incorporation within the acrylic denture base material can improve its viscoelastic properties. PMID:26038651

  5. Kaempferol, a potential cytostatic and cure for inflammatory disorders.

    PubMed

    Rajendran, Peramaiyan; Rengarajan, Thamaraiselvan; Nandakumar, Natarajan; Palaniswami, Rajendran; Nishigaki, Yutaka; Nishigaki, Ikuo

    2014-10-30

    Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g., tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries, and grapes) and in plants or botanical products commonly used in traditional medicine (e.g., Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Its anti-oxidant/anti-inflammatory effects have been demonstrated in various disease models, including those for encephalomyelitis, diabetes, asthma, and carcinogenesis. Moreover, kaempferol act as a scavenger of free radicals and superoxide radicals as well as preserve the activity of various anti-oxidant enzymes such as catalase, glutathione peroxidase, and glutathione-S-transferase. The anticancer effect of this flavonoid is mediated through different modes of action, including anti-proliferation, apoptosis induction, cell-cycle arrest, generation of reactive oxygen species (ROS), and anti-metastasis/anti-angiogenesis activities. In addition, kaempferol was found to exhibit its anticancer activity through the modulation of multiple molecular targets including p53 and STAT3, through the activation of caspases, and through the generation of ROS. The anti-tumor effects of kaempferol have also been investigated in tumor-bearing mice. The combination of kaempferol and conventional chemotherapeutic drugs produces a greater therapeutic effect than the latter, as well as reduces the toxicity of the latter. In this review, we summarize the anti-oxidant/anti-inflammatory and anticancer effects of kaempferol with a focus on its molecular targets and the possible use of this flavonoid for the treatment of inflammatory diseases and cancer. PMID:25147152

  6. Claudin 4-targeted protein incorporated into PLGA nanoparticles can mediate M cell targeted delivery

    PubMed Central

    Rajapaksa, Thejani E.; Stover-Hamer, Mary; Fernandez, Xiomara; Eckelhoefer, Holly A.; Lo, David D.

    2009-01-01

    Polymer-based microparticles are in clinical use mainly for their ability to provide controlled release of peptides and compounds, but they are also being explored for their potential to deliver vaccines and drugs as suspensions directly into mucosal sites. It is generally assumed that uptake is mediated by epithelial M cells, but this is often not directly measured. To study the potential for optimizing M cell uptake of polymer microparticles in vivo, we produced sub-micron size PLGA particles incorporating a recombinant protein. This recombinant protein was produced with or without a c-terminal peptide previously shown to have high affinity binding to Claudin 4, a protein associated with M cell endocytosis. While the PLGA nanoparticles incorporate the protein throughout the matrix, much of the protein was also displayed on the surface, allowing us to take advantage of the binding activity of the targeting peptide. Accordingly, we found that instillation of these nanoparticles into the nasal passages or stomach of mice was found to significantly enhance their uptake by upper airway and intestinal M cells. Our results suggest that a reasonably simple nanoparticle manufacture method can provide insight into developing an effective needle-free delivery system. PMID:19896996

  7. The incorporation of nanoparticles into conventional glass-ionomer dental restorative cements.

    PubMed

    Gjorgievska, Elizabeta; Van Tendeloo, Gustaaf; Nicholson, John W; Coleman, Nichola J; Slipper, Ian J; Booth, Samantha

    2015-04-01

    Conventional glass-ionomer cements (GICs) are popular restorative materials, but their use is limited by their relatively low mechanical strength. This paper reports an attempt to improve these materials by incorporation of 10 wt% of three different types of nanoparticles, aluminum oxide, zirconium oxide, and titanium dioxide, into two commercial GICs (ChemFil Rock and EQUIA Fil). The results indicate that the nanoparticles readily dispersed into the cement matrix by hand mixing and reduced the porosity of set cements by filling the empty spaces between the glass particles. Both cements showed no significant difference in compressive strength with added alumina, and ChemFil Rock also showed no significant difference with zirconia. By contrast, ChemFil Rock showed significantly higher compressive strength with added titania, and EQUIA Fil showed significantly higher compressive strength with both zirconia and titania. Fewer air voids were observed in all nanoparticle-containing cements and this, in turn, reduced the development of cracks within the matrix of the cements. These changes in microstructure provide a likely reason for the observed increases in compressive strength, and overall the addition of nanoparticles appears to be a promising strategy for improving the physical properties of GICs. PMID:25691120

  8. Facilitating the mineralization of oligo(poly(ethylene glycol) fumarate) hydrogel by incorporation of hydroxyapatite nanoparticles.

    PubMed

    Nejadnik, M Reza; Mikos, Antonios G; Jansen, John A; Leeuwenburgh, Sander C G

    2012-05-01

    Exploring strategies to induce the mineralization of hydrogels is an important step toward the development of hydrogel-based materials for bone regeneration. In the current study, the effect of incorporating hydroxyapatite (HA) nanoparticles on the mineralization capacity of an inert poly(ethylene glycol) (PEG)-based hydrogel was investigated. HA nanoparticles were either directly loaded into oligo(poly(ethylene glycol) fumarate) (OPF) hydrogel or loaded into commonly used gelatin microsphere porogens that were subsequently integrated in the OPF matrix. Mineralization of composites after immersion of the samples in simulated body fluid up to 28 days was assessed. In contrast to the blank OPF hydrogel, the HA-containing constructs strongly mineralized such that the average rate of calcium uptake by the material was enhanced by orders of magnitude. The mineral formed was observed to be apatitic and needle shaped. The presented method allows modification of inert PEG-based hydrogels into bioactive biomaterials for applications in bone regeneration. PMID:22374694

  9. Incorporation of liquid lipid in lipid nanoparticles for ocular drug delivery enhancement.

    PubMed

    Shen, Jie; Sun, Minjie; Ping, Qineng; Ying, Zhi; Liu, Wen

    2010-01-15

    The present work investigates the effect of liquid lipid incorporation on the physicochemical properties and ocular drug delivery enhancement of nanostructured lipid carriers (NLCs) and attempts to elucidate in vitro and in vivo the potential of NLCs for ocular drug delivery. The CyA-loaded or fluorescein-marked nanocarriers composed of Precifac ATO 5 and Miglyol 840 (as liquid lipid) were prepared by melting-emulsion technology, and the physicochemical properties of nanocarriers were determined. The uptake of nanocarriers by human corneal epithelia cell lines (SDHCEC) and rabbit cornea was examined. Ex vivo fluorescence imaging was used to investigate the ocular distribution of nanocarriers. The in vitro cytotoxicity and in vivo acute tolerance were evaluated. The higher drug loading capacity and improved in vitro sustained drug release behavior of lipid nanoparticles was found with the incorporation of liquid lipid in lipid nanoparticles. The uptake of nanocarriers by the SDHCEC was increased with the increase in liquid lipid loading. The ex vivo fluorescence imaging of the ocular tissues indicated that the liquid lipid incorporation could improve the ocular retention and penetration of ocular therapeutics. No alternation was macroscopically observed in vivo after ocular surface exposure to nanocarriers. These results indicated that NLC was a biocompatible and potential nanocarrier for ocular drug delivery enhancement. PMID:19955616

  10. Incorporation of liquid lipid in lipid nanoparticles for ocular drug delivery enhancement

    NASA Astrophysics Data System (ADS)

    Shen, Jie; Sun, Minjie; Ping, Qineng; Ying, Zhi; Liu, Wen

    2010-01-01

    The present work investigates the effect of liquid lipid incorporation on the physicochemical properties and ocular drug delivery enhancement of nanostructured lipid carriers (NLCs) and attempts to elucidate in vitro and in vivo the potential of NLCs for ocular drug delivery. The CyA-loaded or fluorescein-marked nanocarriers composed of Precifac ATO 5 and Miglyol 840 (as liquid lipid) were prepared by melting-emulsion technology, and the physicochemical properties of nanocarriers were determined. The uptake of nanocarriers by human corneal epithelia cell lines (SDHCEC) and rabbit cornea was examined. Ex vivo fluorescence imaging was used to investigate the ocular distribution of nanocarriers. The in vitro cytotoxicity and in vivo acute tolerance were evaluated. The higher drug loading capacity and improved in vitro sustained drug release behavior of lipid nanoparticles was found with the incorporation of liquid lipid in lipid nanoparticles. The uptake of nanocarriers by the SDHCEC was increased with the increase in liquid lipid loading. The ex vivo fluorescence imaging of the ocular tissues indicated that the liquid lipid incorporation could improve the ocular retention and penetration of ocular therapeutics. No alternation was macroscopically observed in vivo after ocular surface exposure to nanocarriers. These results indicated that NLC was a biocompatible and potential nanocarrier for ocular drug delivery enhancement.

  11. Incorporation of Ag metallic nanoparticles in 3D gelatin matrix via the green strategy solution plasma.

    PubMed

    Pootawang, Panuphong; Kim, Seong Cheol; Kim, Jung Wan; Lee, Sang Yul

    2013-01-01

    The environmental concern pays much attention to the recent cause of the global warming effect. The reduction of the chemical uses is one of many ways to avoid this crucial problem. Herein, the green process for silver nanometallic particle formation and incorporation in gelatin are proposed. By using a novel discharge process in solution named solution plasma, the silver nanometallic particle formation and its incorporation in gelatin could be accomplished in one-batch reactor during discharge by using silver nitrate (AgNO3) solution as the precursor and controlling systematical parameters. The three-dimensional scaffolds of gelatin/silver biocomposite were fabricated using lyophilizer and the water-soluble property of gelatin was improved by irradiation of ultraviolet ray. The well dispersed silver nanoparticles with the mean particle size 10-20 nm in the good texture of gelatin matrix were obtained. The density of micropore in gelatin/silver scaffold was proportional to the gelatin concentration. In addition, thermal stability of prepared samples had no change comparing with pure gelatin, indicating that the incorporation of silver nanoparticles in gelatin matrix did not affect to the nature of gelatin. PMID:23646779

  12. The chemopreventive effect of the dietary compound kaempferol on the MCF-7 human breast cancer cell line is dependent on inhibition of glucose cellular uptake.

    PubMed

    Azevedo, Cláudia; Correia-Branco, Ana; Araújo, João R; Guimarães, João T; Keating, Elisa; Martel, Fátima

    2015-01-01

    Our aim was to investigate the effect of several dietary polyphenols on glucose uptake by breast cancer cells. Uptake of (3)H-deoxy-D-glucose ((3)H-DG) by MCF-7 cells was time-dependent, saturable, and inhibited by cytochalasin B plus phloridzin. In the short-term (26 min), myricetin, chrysin, genistein, resveratrol, kaempferol, and xanthohumol (10-100 µM) inhibited (3)H-DG uptake. Kaempferol was found to be the most potent inhibitor of (3)H-DG uptake [IC50 of 4 µM (1.6-9.8)], behaving as a mixed-type inhibitor. In the long-term (24 h), kaempferol (30 µM) was also able to inhibit (3)H-DG uptake, associated with a 40% decrease in GLUT1 mRNA levels. Interestingly enough, kaempferol (100 µM) revealed antiproliferative (sulforhodamine B and (3)H-thymidine incorporation assays) and cytotoxic (extracellular lactate dehydrogenase activity determination) properties, which were mimicked by low extracellular (1 mM) glucose conditions and reversed by high extracellular (20 mM) glucose conditions. Finally, exposure of cells to kaempferol (30 µM) induced an increase in extracellular lactate levels over time (to 731 ± 32% of control after a 24 h exposure), due to inhibition of MCT1-mediated lactate cellular uptake. In conclusion, kaempferol potently inhibits glucose uptake by MCF-7 cells, apparently by decreasing GLUT1-mediated glucose uptake. The antiproliferative and cytotoxic effect of kaempferol in these cells appears to be dependent on this effect. PMID:25719685

  13. Incorporation and release of drug into/from superparamagnetic iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Maver, Uro; Bele, Marjan; Makovec, Darko; ?ampelj, Stanislav; Jamnik, Janko; Gaber?ek, Miran

    2009-10-01

    The aim of this study was to attach a model drug (naproxen) onto superparamagnetic iron oxide nanoparticles (SPION). First, SPION were coated with thin layer of silica that contained micropores. We demonstrated that such surface functionalization could be optimized by the use of citric acid which prevented SPION agglomeration during the procedure. HRTEM investigation showed a uniform 1-2-nm-thick silica coating around SPION. This coating did not affect significantly the magnetic properties of the SPION. Into the coated SPION we successfully incorporated about 30 wt% of naproxen. The latter was readily released after immersion into a testing solution. The composites could be interesting for potential use in diagnostics.

  14. Recent Updates of DNA Incorporated in Carbon Nanotubes and Nanoparticles for Electrochemical Sensors and Biosensors

    PubMed Central

    Yogeswaran, Umasankar; Thiagarajan, Soundappan; Chen, Shen-Ming

    2008-01-01

    Innovations in the field of electrochemical sensors and biosensors are of much importance nowadays. These devices are designed with probes and micro electrodes. The miniaturized designs of these sensors allow analyses of materials without damaging the samples. Some of these sensors are also useful for real time analysis within the host system, so these sensors are considered to be more advantageous than other types of sensors. The active sensing materials used in these types of sensors can be any material that acts as a catalyst for the oxidation or reduction of particular analyte or set of analytes. Among various kinds of sensing materials, deoxyribonucleic acid (DNA), carbon nanotubes (CNTs) and nanoparticles have received considerable attraction in recent years. DNA is one of the classes of natural polymers, which can interact with CNTs and nanoparticles to form new types of composite materials. These composite materials have also been used as sensing materials for sensor applications. They have advantages in characteristics such as extraordinary low weight and multifunctional properties. In this article, advantages of DNA incorporated in CNT and nanoparticle hybrids for electrochemical sensors and biosensors are presented in detail, along with some key results noted from the literature.

  15. Preparation and Characterization of Selenium Incorporated Guar Gum Nanoparticle and Its Interaction with H9c2 Cells

    PubMed Central

    Soumya, Rema Sreenivasan; Vineetha, Vadavanath Prabhakaran; Reshma, Premachandran Latha; Raghu, Kozhiparambil Gopalan

    2013-01-01

    This study deals with the preparation and characterization of selenium incorporated guar gum nanoparticle (SGG), and its effect on H9c2 cardiomyoblast. Herein, nanoprecipitation techniques had been employed for the preparation of SGG nanoparticle. The prepared nanoparticle had been subjected to various types of analytical techniques like transmission electron microscopy (TEM), X-ray diffraction (XRD) and particle size analysis to confirm the characteristics of nanoparticle as well as for selenium incorporation. Physical characterization of nanoparticle showed that the size of nanoparticles increase upto ∼69–173 nm upon selenium incorporation from ∼41–132 nm. Then the prepared nanoparticles were evaluated for its effect on H9c2 cells. In this regard, the effect of nanoparticle on various vital parameters of H9c2 cells was studied. Parameters like cell viability, uptake of selenium incorporated guar gum nanoparticle by the cells, effect of SGG on DNA integrity, apoptosis, reactive oxygen species generation, alteration in transmembrane potential of mitochondria and cytoskeletal integrity had been investigated. Viability results showed that up to 25 nM of SGG was safe (10.31%) but beyond that it induces cytotoxicity. Cellular uptake of selenium showed that cell permeability for SGG is significantly high compared to normal selenium (7.2 nM of selenium for 25 nM SGG compared with 5.2 nM selenium for 25 nM sodium selenite). There was no apoptosis with SGG and also it protects DNA from hydroxyl radical induced breakage. Likewise no adverse effect on mitochondria and cytoskeleton was observed for 25 nM of SGG. Overall results reveal that SGG is highly suitable for biomedical research application. PMID:24098647

  16. Kaempferol inhibits the growth and metastasis of cholangiocarcinoma in vitro and in vivo.

    PubMed

    Qin, Youyou; Cui, Wu; Yang, Xuewei; Tong, Baifeng

    2016-03-01

    Kaempferol is a flavonoid that has been reported to exhibit antitumor activity in various malignant tumors. However, the role of kaempferol on cholangiocarcinoma (CCA) is largely unknown. In this article, we found that kaempferol inhibited proliferation, reduced colony formation ability, and induced apoptosis in HCCC9810 and QBC939 cells in vitro. Results from transwell assay and wound-healing assay demonstrated that kaempferol significantly suppressed the migration and invasion abilities of HCCC9810 and QBC939 cells in vitro. Kaempferol was found to decrease the expression of Bcl-2 and increase the expressions of Bax, Fas, cleaved-caspase 3, cleaved-caspase 8, cleaved-caspase 9, and cleaved-PARP. In addition, kaempferol also downregulated the levels of phosphorylated AKT, TIMP2, and MMP2. In vivo, it was found that the volume of subcutaneous xenograft (0.15 cm(3)) in the kaempferol-treated group was smaller than that (0.6 cm(3)) in the control group. Kaempferol also suppressed the number and volume of metastasis foci in the lung metastasis model, with no marked effects on body weight of mice. Immunohistochemistry assay showed that the number of Ki-67-positive cells was lower in the kaempferol-treated group than that in the control group. We further confirmed that the changes of apoptosis- and invasion-related proteins after kaempferol treatment in vivo were similar to the results in vitro. These data suggest that kaempferol may be a promising candidate agent for the treatment of CCA. PMID:26883800

  17. Kaempferol enhances the suppressive function of Treg cells by inhibiting FOXP3 phosphorylation.

    PubMed

    Lin, Fang; Luo, Xuerui; Tsun, Andy; Li, Zhiyuan; Li, Dan; Li, Bin

    2015-10-01

    Kaempferol is a natural flavonoid found in many vegetables and fruits. Epidemiologic studies have described that Kaempferol intake could reduce risk of cancer, especially lung, gastric, pancreatic and ovarian cancers. Recent studies have shown that Kaempferol could also be beneficial to the body to defend against inflammation, and infection by bacteria and viruses; however, the molecular mechanism of its immunoregulatory function remains largely unknown. Through screening a small molecule library of traditional Chinese medicine (TCM), we identified that Kaempferol could enhance the suppressive function of regulatory T cells (Tregs). Kaempferol was found to increase FOXP3 expression level in Treg cells and prevent pathological symptoms of collagen-induced arthritis in a rat animal model. Kaempferol could also reduce PIM1-mediated FOXP3 phosphorylation at S422. Our study reveals a molecular mechanism that underlies the anti-inflammatory action of Kaempferol for the prevention and treatment of inflammatory diseases such as rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis. PMID:25870037

  18. Rapid synthesis of ordered hexagonal mesoporous silica and their incorporation with Ag nanoparticles by solution plasma

    SciTech Connect

    Pootawang, Panuphong; Saito, Nagahiro; Takai, Osamu; Lee, Sang Yul

    2012-10-15

    Graphical abstract: Overall reactions of mesoporous silica and AgNPs-incorporated mesoporous silica syntheses by solution plasma process (SPP). Highlights: ? SPP for rapid synthesis of mesoporous silica. ? SPP for rapid synthesis of mesoporous silica and AgNPs incorporation. ? Higher surface area and larger pore diameter of mesoporous silica synthesized by SPP. -- Abstract: Rapid synthesis of silica with ordered hexagonal mesopore arrangement was obtained using solution plasma process (SPP) by discharging the mixture of P123 triblock copolymer/TEOS in acid solution. SPP, moreover, was utilized for Ag nanoparticles (AgNPs) incorporation in silica framework as one-batch process using silver nitrate (AgNO{sub 3}) solution as precursor. The turbid silicate gel was clearly observed after discharge for 1 min and the white precipitate formed at 3 min. The mesopore with hexagonal arrangement and AgNPs were observed in mesoporous silica. Two regions of X-ray diffraction patterns (2? < 2 and 2? = 3590) corresponded to the mesoporous silica and Ag nanocrystal characteristics. Comparing with mesoporous silica prepared by a conventional solgel route, surface area and pore diameter of mesoporous silica prepared by solution plasma were observed to be larger. In addition, the increase in Ag loading resulted in the decrease in surface area with insignificant variation in the pore diameter of mesoporous silica. SPP could be successfully utilized not only to enhance gelation time but also to increase surface area and pore diameter of mesoporous silica.

  19. Hair dye-incorporated poly-?-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation

    PubMed Central

    Lee, Hye-Young; Jeong, Young-IL; Choi, Ki-Choon

    2011-01-01

    Background p-Phenylenediamine (PDA) or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair dyes such as PDA are known to have potent contact allergy reactions in humans, and severe allergic reactions are problematic. Methods PDA-incorporated nanoparticles were prepared based on ion-complex formation between the cationic groups of PDA and the anionic groups of poly(?-glutamic acid) (PGA). To reinforce PDA/PGA ion complexes, glycol chitosan (GC) was added. PDA-incorporated nanoparticles were characterized using field-emission scanning electron microscopy, Fourier- transform infrared (FT-IR) spectroscopy, dynamic light scattering, and powder X-ray diffractometry (XRD). Results Nanoparticles were formed by ion-complex formation between the amine groups of PDA and the carboxyl groups of PGA. PDA-incorporated nanoparticles are small in size (<100 nm), and morphological observations showed spherical shapes. FT-IR spectra results showed that the carboxylic acid peak of PGA decreased with increasing PDA content, indicating that the ion complexes were formed between the carboxyl groups of PGA and the amine groups of PDA. Furthermore, the intrinsic peak of the carboxyl groups of PGA was also decreased by the addition of GC. Intrinsic crystalline peaks of PDA were observed by XRD. This crystalline peak of PDA was completely nonexistent when nanoparticles were formed by ion complex between PDA, PGA, and GC, indicating that PDA was complexed with PGA and no free drug existed in the formulation. During the drug-release experiment, an initial burst release of PDA was observed, and then PDA was continuously released over 1 week. Cytotoxicity testing against HaCaT human skin keratinocyte cells showed PDA-incorporated nanoparticles had lower toxicity than PDA itself. Furthermore, PDA-incorporated nanoparticles showed reduced apoptosis and necrosis reaction at HaCaT cells. Conclusion The authors suggest that these microparticles are ideal candidates for a vehicle for decreasing side effects of hair dye. PMID:22131834

  20. Nanocomposites Fabricated by a Combination of Green Compact Nanoparticle Incorporation and Ultrasonic Treatment of the Melted Compact

    NASA Astrophysics Data System (ADS)

    Kandemir, Sinan; Atkinson, Helen V.; Weston, David P.; Hainsworth, Sarah V.

    2014-11-01

    Thixoforming is a type of semi-solid processing which is based on forming metals in the semi-solid state rather than fully liquid or solid state. There have been no reports of the thixoforming of nanocomposites in the literature. The incorporation of ceramic nanoparticles into liquid metals is a challenging task for the fabrication of metal matrix nanocomposites due to their large surface-to-volume ratio and poor wettability. Previous research work by a number of workers has highlighted the challenges with the incorporation of nanoparticles into liquid aluminum alloy. In the present study, SiC and TiB2 nanoparticles with an average diameter between 20 and 30 nm were firstly incorporated into green compacts by a powder forming route, and then the compacts were melted and treated ultrasonically. The microstructural studies reveal that the engulfment and relatively effective distribution of the nanoparticles into the melt were achieved. The hardness was considerably improved with only 0.8 wt pct addition of the nanoparticles. The nanocomposites were successfully thixoformed at a solid fraction between 0.65 and 0.70. The microstructures, hardness, and tensile mechanical properties of the thixoformed nanocomposites were investigated and compared with those of the as-received A356 and thixoformed A356 alloys. The tensile properties of the thixoformed nanocomposites were significantly enhanced compared to thixoformed A356 alloy without reinforcement, indicating the strengthening effects of the nanoparticles.

  1. Inhibitory kinetics and mechanism of kaempferol on ?-glucosidase.

    PubMed

    Peng, Xi; Zhang, Guowen; Liao, Yijing; Gong, Deming

    2016-01-01

    ?-Glucosidase is a therapeutic target for diabetes mellitus, and ?-glucosidase inhibitors play a vital role in the treatments for the disease. As a kind of potentially safer ?-glucosidase inhibitor, flavonoids have attached much attention currently. In this study, kaempferol was found to show a notable inhibition activity on ?-glucosidase in a mixed-type manner with IC50 value of (1.16 0.04) 10(-5) mol L(-1). Analyses of fluorescence, circular dichroism and Fourier transform infrared spectra indicated that kaempferol bound to ?-glucosidase with high affinity which was mainly driven by hydrogen bonds and van der Waals forces, and this binding resulted in conformational alteration of ?-glucosidase. Further molecular docking study validated the experimental results. It was proposed that kaempferol may interact with some amino acid residues located within the active site of ?-glucosidase, occupying the catalytic center of the enzyme to avoid the entrance of p-nitrophenyl-?-D-glucopyranoside and ultimately inhibiting the enzyme activity. PMID:26212963

  2. Antimicrobial activity of cream incorporated with silver nanoparticles biosynthesized from Withania somnifera

    PubMed Central

    Marslin, Gregory; Selvakesavan, Rajendran K; Franklin, Gregory; Sarmento, Bruno; Dias, Alberto CP

    2015-01-01

    We report on the antimicrobial activity of a cream formulation of silver nanoparticles (AgNPs), biosynthesized using Withania somnifera extract. Aqueous extracts of leaves promoted efficient green synthesis of AgNPs compared to fruits and root extracts of W. somnifera. Biosynthesized AgNPs were characterized for their size and shape by physical-chemical techniques such as UV-visible spectroscopy, laser Doppler anemometry, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray energy dispersive spectroscopy. After confirming the antimicrobial potential of AgNPs, they were incorporated into a cream. Cream formulations of AgNPs and AgNO3 were prepared and compared for their antimicrobial activity against human pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, and Candida albicans) and a plant pathogen (Agrobacterium tumefaciens). Our results show that AgNP creams possess significantly higher antimicrobial activity against the tested organisms. PMID:26445537

  3. Incorporation and controlled release of silyl ether prodrugs from PRINT nanoparticles.

    PubMed

    Parrott, Matthew C; Finniss, Mathew; Luft, J Chris; Pandya, Ashish; Gullapalli, Anuradha; Napier, Mary E; DeSimone, Joseph M

    2012-05-01

    Asymmetric bifunctional silyl ether (ABS) prodrugs of chemotherapeutics were synthesized and incorporated within 200 nm 200 nm particles. ABS prodrugs of gemcitabine were selected as model compounds because of the difficulty to encapsulate a water-soluble drug within a hydrogel. The resulting drug delivery systems were degraded under acidic conditions and were found to release only the parent or active drug. Furthermore, changing the steric bulk of the alkyl substituents on the silicon atom could regulate the rate of drug release and, therefore, the intracellular toxicity of the gemcitabine-loaded particles. This yielded a family of novel nanoparticles that could be tuned to release drug over the course of hours, days, or months. PMID:22545784

  4. Incorporation and Controlled Release of Silyl Ether Prodrugs from PRINT Nanoparticles

    PubMed Central

    Parrott, Matthew C.; Finniss, Mathew; Luft, J. Chris; Pandya, Ashish; Gullapalli, Anuradha; Napier, Mary E.; DeSimone, Joseph M.

    2012-01-01

    Asymmetric bifunctional silyl ether (ABS) prodrugs of chemotherapeutics were synthesized and incorporated within 200 nm x 200 nm particles. ABS prodrugs of gemcitabine were selected as model compounds because of the difficulty to encapsulate a water soluble drug within a hydrogel. The resulting drug delivery systems were degraded under acidic conditions and were found to release only the parent or active drug. Furthermore, changing the steric bulk of the alkyl substituents on the silicon atom could regulate the rate of drug release and therefore the intracellular toxicity of the gemcitabine-loaded particles. This yielded a family of novel nanoparticles that could be tuned to release drug over the course of hours, days, or months. PMID:22545784

  5. Antimicrobial activity of cream incorporated with silver nanoparticles biosynthesized from Withania somnifera.

    PubMed

    Marslin, Gregory; Selvakesavan, Rajendran K; Franklin, Gregory; Sarmento, Bruno; Dias, Alberto C P

    2015-01-01

    We report on the antimicrobial activity of a cream formulation of silver nanoparticles (AgNPs), biosynthesized using Withania somnifera extract. Aqueous extracts of leaves promoted efficient green synthesis of AgNPs compared to fruits and root extracts of W. somnifera. Biosynthesized AgNPs were characterized for their size and shape by physical-chemical techniques such as UV-visible spectroscopy, laser Doppler anemometry, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray energy dispersive spectroscopy. After confirming the antimicrobial potential of AgNPs, they were incorporated into a cream. Cream formulations of AgNPs and AgNO3 were prepared and compared for their antimicrobial activity against human pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, and Candida albicans) and a plant pathogen (Agrobacterium tumefaciens). Our results show that AgNP creams possess significantly higher antimicrobial activity against the tested organisms. PMID:26445537

  6. SERS detection and antibacterial activity from uniform incorporation of Ag nanoparticles with aligned Si nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Chia-Yun; Hsu, Li-Jen; Hsiao, Po-Hsuan; Yu, Chang-Tze Ricky

    2015-11-01

    We present a facile, reliable and controllable two-steps electroless deposition for uniformly decorating the silver (Ag) nanoparticles (NPs) on the highly aspect ratio of silicon (Si) nanowire arrays. Different from the direct Ag-loading process, which is normally challenged by the non-uniform coating of Ag, the formation of Ag NPs using such innovative electroless process is no longer to be limited at top nanowire surfaces solely; instead, each Ag+/Si interface can initiate the galvanic reduction of Ag+ ions, thus resulting in the uniform formation of Ag NPs on the entire Si nanowire arrays. In addition, systematic explorations of surface-enhanced Raman scattering (SERS) capability as well as antibacterial activity of the Ag/Si-incorporated nanostructures were performed, and the optimized Ag loadings on Si nanowire-based substrates along with the kinetic investigations were further revealed, which may benefit their practical applications in sensing, medical and biological needs.

  7. Behavior and anti-glioma effect of lapatinib-incorporated lipoprotein-like nanoparticles

    NASA Astrophysics Data System (ADS)

    Gao, Huile; Yang, Zhi; Cao, Shijie; Xi, Zhangjie; Zhang, Shuang; Pang, Zhiqing; Jiang, Xinguo

    2012-11-01

    The purpose of the investigation was to prepare a new type of nanoparticle, namely lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs), and to evaluate the behavior and anti-glioma effect of LTNPs. LTNPs were prepared and characterized using the Cyro-transmission electron microscope (Cryo-TEM) and Raman scan methods. Cellular uptake and subcellular localization studies were performed to evaluate the in vitro behavior of LTNPs. An in vivo imaging technique was used for the evaluation of the targeting of LTNPs. To study the anti-glioma effect, glioma xenografts were used. The particle size of LTNPs was 92.6 nm, and the zeta potential was 28.40 mV. LTNPs contained a surface layer that was obviously different from the core, according to the Cryo-TEM analysis. A Raman scan analysis demonstrated the incorporation of lapatinib in LTNPs, and it also revealed a structure different from free lapatinib. The uptake of LTNP by U87 cells occurred in a concentration- and time-dependent manner. According to the subcellular study, the uptake of LTNPs was endosome mediated. LTNPs could distribute and accumulate in the tumor site by an enhanced permeation and retention effect. Both LTNPs (10 mg kg-1) and LTNPs (30 mg kg-1) could significantly inhibit the growth of U87 xenografts. For a similar antitumor effect, the required cumulative dose of LTNPs was only 5% compared to that of Tykerb (the commercial formulation of lapatinib). This study demonstrated the effective uptake of LTNPs by U87 cells, the passive targeting of LTNPs at tumors and the better antitumor effect of LTNPs.

  8. Enhanced recovery and dissolution of griseofulvin nanoparticles from surfactant-free nanocomposite microparticles incorporating wet-milled swellable dispersants.

    PubMed

    Bhakay, Anagha; Azad, Mohammad; Vizzotti, Emanuel; Dave, Rajesh N; Bilgili, Ecevit

    2014-11-01

    Nanocomposite microparticles (NCMPs) incorporating drug nanoparticles and wet-milled swellable dispersant particles were investigated as a surfactant-free drug delivery vehicle with the goal of enhancing the nanoparticle recovery and dissolution rate of poorly water-soluble drugs. Superdisintegrants were used as inexpensive, model, swellable dispersant particles by incorporating them into NCMP structure with or without wet-stirred media milling along with the drug. Suspensions of griseofulvin (GF, model drug) along with various dispersants produced by wet-milling were coated onto Pharmatose® to prepare NCMPs in a fluidized bed process. Hydroxypropyl cellulose (HPC, polymer) alone and with sodium dodecyl sulfate (SDS, surfactant) was used as base-line stabilizer/dispersant during milling. Croscarmellose sodium (CCS, superdisintegrant) and Mannitol were used as additional dispersants to prepare surfactant-free NCMPs. Nanoparticle recovery during redispersion and dissolution of the various GF-laden NCMPs were examined. Suspensions prepared by co-milling GF/HPC/CCS or milling GF/HPC/SDS were stable after 30 h of storage. After drying, due to its extensive swelling capacity, incorporation of wet-milled CCS in the NCMPs caused effective breakage of the NCMP structure and bursting of nanoparticle clusters, ultimately leading to fast recovery of the GF nanoparticles. Optimized wet co-milling and incorporation of CCS in NCMP structure led to superior dispersant performance over incorporation of unmilled CCS or physically mixed unmilled CCS with NCMPs. The enhanced redispersion correlated well with the fast GF dissolution from the NCMPs containing either CCS particles or SDS. Overall, swellable dispersant (CCS) particles, preferably in multimodal size distribution, enable a surfactant-free formulation for fast recovery/dissolution of the GF nanoparticles. PMID:23981202

  9. Electrospun strontium titanata nanofibers incorporated with nickel oxide nanoparticles for improved photocatalytic activities

    NASA Astrophysics Data System (ADS)

    Alharbi, Abdulaziz; Alarifi, Ibrahim M.; Khan, Waseem S.; Asmatulu, Ramazan

    2015-03-01

    The inexpensive sources of fossil fuels in the world are limited, and will deplete soon because of the huge demand on the energy and growing economies worldwide. Thus, many research activities have been focused on the non-fossil fuel based energy sources, and this will continue next few decades. Water splitting using photocatalysts is one of the major alternative energy technologies to produce hydrogen directly from water using photon energy of the sun. Numerous solid photocatalysts have been used by researchers for water splitting. In the present study, nickel oxide and strontium titanata were chosen as photocatalysts for water splitting. Poly (vinyl pyrrolidone) (PVP) was incorporated with nickel oxide [Ni2O3] (co-catalyst), while poly (vinyl acetate) (PVAc) was mixed with titanium (IV) isopropoxide [C12H28O4Ti] and strontium nitrate [Sr(NO3)2]. Then, two solutions were electrospun using coaxial electrospinning technique to generate nanoscale fibers incorporated with NiOx nanoparticles. The fibers were then heat treated at elevated temperatures for 2hr in order to transform the strontium titanata and nickel oxide into crystalline form for a better photocatalytic efficiency. The morphology of fibers was characterized via scanning electron microscopy (SEM), while the surface hydrophobicity was determined using water contact angle goniometer. The UV-vis spectrophotometer was also used to determine the band gap energy values of the nanofibers. This study may open up new possibilities to convert water into fuel directly using the novel photocatalysts.

  10. Surface plasmon-enhanced quantum dot light-emitting diodes by incorporating gold nanoparticles.

    PubMed

    Pan, Jiangyong; Chen, Jing; Zhao, Dewei; Huang, Qianqian; Khan, Qasim; Liu, Xiang; Tao, Zhi; Zhang, Zichen; Lei, Wei

    2016-01-25

    Surface plasmon-enhanced electroluminescence (EL) has been demonstrated by incorporating gold (Au) nanoparticles (NPs) in quantum dot light-emitting diode (QLED). Time-resolved photoluminescence (TRPL) spectroscopy reveals that the EL enhancement is ascribed to the near-field enhancement through an effective coupling between excitons of the quantum dot emitters and localized surface plasmons around Au NPs. It is found that the size of Au NPs and the distance between the Au NPs and the emissive layer have significant effects on the performance of QLED. The enhancement can be maximized as the SP resonance wavelength of Au NPs matches well with the PL emission wavelength of the QD film and the distance between Au NPs and the emissive layer maintains 15 nm. The photoluminance (PL) and EL intensity can be enhanced by 4.4 and 1.7 folds with the incorporation of Au NPs. The maximum current efficiency of 4.56 cd/A can be achieved for the resulting QLEDs by incorprating Au NPs with an enhancement factor of 2.0. In addition, the enhancement ratio of 2.2 can be achieved for the lifetime of resulting QLED. PMID:26832585

  11. RuO2 nanoparticles dispersed on carbon nanotubes with high electrochemical activity using N incorporation

    NASA Astrophysics Data System (ADS)

    Fang, Wei-Chuan

    2008-04-01

    The N incorporation into carbon nanotubes (CNTs) supporting ultrafine RuO2 nanoparticles (NPs) has been studied. With increasing N dopant, the Raman spectrum shifts to higher wavenumbers and x-ray photoelectron spectroscopy results show the intensity ratio of graphene- to pyridine-like bonding is reduced. Cross-sectional scanning electron microscope images reveal that the uniform RuO2 NPs are dispersed on CNTs at the N2 flow rate of 20 sccm. Electrochemical (EC) measurements show N-doped CNTs covered with RuO2 NPs at an N2 flow rate of 20 sccm provide the optimal capacitive behavior with larger energy density and can be performed at the higher scan rate of 2000 mV s-1. The distribution of RuO2 NPs on CNT surfaces deduced from N-induced defect sites is the key point in controlling the capacitive characteristics of CNT-RuO2 nanocomposites (NCs). The high capacitance is due to the well-dispersed RuO2 particles on CNTs incorporated with N atoms. Such NCs are promising for energy storage devices with high EC efficiency.

  12. Beneficial properties of selenium incorporated guar gum nanoparticles against ischemia/reperfusion in cardiomyoblasts (H9c2).

    PubMed

    Soumya, R S; Vineetha, V P; Salin Raj, P; Raghu, K G

    2014-11-01

    Nanotechnology for the treatment and diagnosis has been emerging recently as a potential area of research and development. In the present study, selenium incorporated guar gum nanoparticles have been prepared by nanoprecipitation and characterized by transmission electron microscopy and particle size analysis. The nanoparticles were screened for antioxidant potential (metal chelation, total reducing power and hydroxyl radical scavenging activity) and were evaluated against the cell line based cardiac ischemia/reperfusion model with special emphasis on oxidative stress and mitochondrial parameters. The cell based cardiac ischemia model was employed using H9c2 cell lines. Investigations revealed that there was a significant alteration (P ? 0.05) in the innate antioxidant status (glutathione?, glutathione peroxidase?, thioredoxin reductase?, superoxide dismutase?, catalase?, lipid peroxidation?, protein carbonyl?, xanthine oxidase? and caspase 3 activity?), mitochondrial functions (reactive oxygen species generation, membrane potential, and pore opening) and calcium homeostasis (calcium ATPase and intracellular calcium overload) during both ischemia and reperfusion. For comparative evaluation, selenium, guar gum and selenium incorporated guar gum nanoparticles were evaluated for their protective properties against ischemia/reperfusion. The study reveals that selenium incorporated guar gum nanoparticles were better at protecting the cells from ischemia/reperfusion compared to selenium and guar gum nanoparticles. The potent antioxidant capability shown by the sample in in vitro assays may be the biochemical basis of its better biological activity. Further, the nanodimensions of the particle may be the additional factor responsible for its better effect. PMID:25307064

  13. Core-shell nano-architectures: the incorporation mechanism of hydrophobic nanoparticles into the aqueous core of a microemulsion.

    PubMed

    Scorciapino, Mariano A; Sanna, Roberta; Ardu, Andrea; Orr, Federica; Casu, Mariano; Musinu, Anna; Cannas, Carla

    2013-10-01

    This work presents an in-depth investigation of the molecular interactions in the incorporation mechanism of colloidal hydrophobic-capped nanoparticles into the hydrophilic core of reverse microemulsions. (1)H Nuclear Magnetic Resonance (NMR) was employed to obtain molecular level details of the interaction between the nanoparticles capping amphiphiles and the microemulsion surfactants. The model system of choice involved oleic acid (OAC) and oleylamine (OAM) as capping molecules, while igepal-CO520 was the surfactant. The former were studied both in their "free" state and "ligated" one, i.e., bound to nanoparticles. The latter was investigated either in cyclohexane (micellar solution) or in water/cyclohexane microemulsions. The approach was extremely useful to gain a deeper understanding of the equilibria involved in this complex system (oleic acid capped-Bi2S3 in igepal/water/cyclohexane microemulsions). In difference to previously proposed mechanisms, the experimental data showed that the high affinity of the capping ligands for the reverse micelle interior was the drivingforce for the incorporation of the nanoparticles. A simple ligand-exchange mechanism could be ruled out. The collected information about the nanoparticle incorporation mechanism is extremely useful to develop new synthetic routes with an improved/tuned coating efficiency, in order to tailor the core-shell structure preparation. PMID:23910706

  14. Effect of titanium oxide nanoparticle incorporation into nm thick coatings deposited using an atmospheric pressure plasma.

    PubMed

    Denis, Dowling P; Barry, Twomey; Gerry, Byrne

    2010-04-01

    This study reports on the use of an atmospheric plasma technique to incorporate metal oxide nanoparticles into nm thick siloxane coatings. Titanium dioxide (TiO2) particles with diameters of 30-80 nm, were mixed with a number of different siloxanes-polydimethylsiloxane, hexamethyldisiloxane and tetraethylorthosilicate (TEOS). The TiO2/TEOS mixture was found to give the most stable suspension, possibly due to the higher surface tension of TEOS compared with the other siloxanes. TiO2/TEOS mixtures with 2 to 10% by weight of the metal oxide were prepared and were then nebulised into a helium/oxygen atmospheric plasma. Polyethylene terepthalate (PET) and silicon wafer substrates were passed through this plasma using a reel-to-reel substrate manipulation system. SEM combined with EDX was used to examine the distribution of the metal oxide particles in the resultant coatings. The TEOS coating thickness without TiO2 addition was 9 nm. The composite coating consisted of a relatively homogeneous distribution of small agglomerates of the TiO2 nanoparticles in TEOS. A linear increase in the titanium surface concentration was observed with increase in the quantity of TiO2 added into the siloxane precursor. The chemical functionality of the siloxane coating was examined using FTIR spectroscopy and no significant spectrum differences was observed with the incorporation of the different concentrations of TiO2 into the polymer. There were also no changes observed in coating surface energy with TiO2 incorporation. Coating morphology was examined using optical profilometry and surface roughness (Ra) values increased from typical values of 0.8 nm for the TEOS coating to 4.1 nm for the TiO2/TEOS coating. The adhesion of the deposited coatings was compared using fragmentation tests. These were carried out through uniaxial tensile loading. The coating cracking pattern after applied strain of 20% was not observed to change significantly with the addition of TiO2 into the siloxane. PMID:20355495

  15. Cystatin incorporated in poly(lactide-co-glycolide) nanoparticles: development and fundamental studies on preservation of its activity.

    PubMed

    Cegnar, Mateja; Kos, Janko; Kristl, Julijana

    2004-08-01

    Preservation of biological activity is still a major challenge for successful formulation and delivery of protein drugs. Cystatin, a potential protein drug in cancer therapy, was incorporated in poly(lactide-co-glycolide) nanoparticles by the water-in-oil-in-water emulsion solvent diffusion technique. In order to preserve the biological activity of cystatin, a specific modification of the method of producing nanoparticles was introduced. The activity of cystatin was strongly influenced by the stirring rate during preparation and, to a lesser extent, by selected organic solvents. A synergistic effect of mechanical stirring and sonication, both at low energy levels, enabled nanoparticles to be formed without denaturing the cystatin. Nanoparticles produced by the optimised method ranged from 300 to 350 nm in diameter with 85% of the starting cystatin activity. The loading efficiency of cystatin depends on polymer type and ranged from 12 to 57%, representing an actual loading of 0.6-2.6% (w/w). Among various cryo-/lyoprotectants bovine serum albumin was identified as the most successful. The use of a protein protectant prior to nanoparticle formation was essential to maintaining the biologically active three-dimensional structure of cystatin. In addition, a specific type of poly(lactide-co-glycolide) polymer, particularly in terms of its functional groups, was identified to be important in retaining cystatin activity. Cystatin incorporated into nanoparticles in this way maintains its structural integrity, making it suitable for effective drug delivery. PMID:15265505

  16. Enhancement of Transdermal Penetration and Bioavailability of Poorly Soluble Acyclovir Using Solid Lipid Nanoparticles Incorporated in Gel Cream

    PubMed Central

    Gide, P. S.; Gidwani, S. K.; Kothule, K. U.

    2013-01-01

    The objective of this work was to increase the amount of acyclovir in the basal epidermis, site of herpes virus simplex infection, using the solid lipid nanoparticles loaded gel cream as carriers. Solid lipid nanoparticles were prepared by high pressure homogenisation method and incorporated in a semisolid submicron gel cream. Acyclovir distribution into rat skin after topical application of solid lipid nanoparticles loaded gel cream was determined by fabricated Franz diffusion cell. The results showed that, the quantity of the acyclovir in the basal epidermis with the solid lipid nanoparticles loaded submicron gel cream was two folds times more than marketed acyclovir gel cream. This type of carrier can improve acyclovir loaded therapy since it increases drug retention in the basal epidermis. PMID:24019560

  17. A review of the dietary flavonoid, kaempferol on human health and cancer chemoprevention

    PubMed Central

    Chen, Allen Y.; Chen, Yi Charlie

    2013-01-01

    Kaempferol is a polyphenol antioxidant found in fruits and vegetables. Many studies have described the beneficial effects of dietary kaempferol in reducing the risk of chronic diseases, especially cancer. Epidemiological studies have shown an inverse relationship between kaempferol intake and cancer. Kaempferol may help by augmenting the bodys antioxidant defense against free radicals, which promote the development of cancer. At the molecular level, kaempferol has been reported to modulate a number of key elements in cellular signal transduction pathways linked to apoptosis, angiogenesis, inflammation, and metastasis. Significantly, kaempferol inhibits cancer cell growth and angiognesis and induces cancer cell apoptosis, but on the other hand, kaempferol appears to preserve normal cell viability, in some cases exerting a protective effect. The aim of this review is to synthesize information concerning the extraction of kaempferol, as well as to provide insights into the molecular basis of its potential chemo-preventative activities, with an emphasis on its ability to control intracellular signaling cascades that regulate the aforementioned processes. Chemoprevention using nanotechnology to improve the bioavailability of kaempferol is also discussed. PMID:23497863

  18. Kaempferol inhibits UVB-induced COX-2 expression by suppressing Src kinase activity

    PubMed Central

    Lee, Kyung Mi; Lee, Ki Won; Jung, Sung Keun; Lee, Eun Jung; Heo, Yong-Seok; Bode, Ann M.; Lubet, Ronald A.; Lee, Hyong Joo; Dong, Zigang

    2010-01-01

    Ultraviolet (UV) radiation is the primary environmental risk factor in the development of nonmelanoma skin cancer, and UVB in particular promotes tumor growth through various signaling pathways. Kaempferol, a flavonoid with anti-inflammatory and anti-oxidative properties, has been studied as a chemopreventive agent; however, little is known regarding its effects on UVB-induced photo-carcinogenesis. Here, we examined the effect of kaempferol on UVB-induced skin inflammation. We found that kaempferol suppressed UVB-induced cyclooxygenase-2 (COX-2) protein expression in mouse skin epidermal JB6 P+ cells and attenuated the UVB-induced transcriptional activities of cox-2 and activator protein-1 (AP-1). Kaempferol attenuated the UVB-induced phosphorylation of several mitogen-activated protein kinases (MAPKs), including ERKs, p38, and JNKs, but had no effect on the phosphorylation of the upstream MAPK regulator Src. However, in vitro and ex vivo kinase assays demonstrated that kaempferol suppressed Src kinase activity. Furthermore, in vivo data from mouse skin support the idea that kaempferol suppresses UVB-induced COX-2 expression by blocking Src kinase activity. A pull-down assay revealed that kaempferol competes with ATP for direct binding to Src. Docking data suggest that kaempferol docks easily into the ATP-binding site of Src, which is located between the N and C lobes of the kinase domain. Taken together, these results suggest that kaempferol is a potent chemopreventive agent against skin cancer through its inhibitory interaction with Src. PMID:20599768

  19. Hydrothermally synthesized PEGylated calcium phosphate nanoparticles incorporating Gd-DTPA for contrast enhanced MRI diagnosis of solid tumors.

    PubMed

    Mi, Peng; Kokuryo, Daisuke; Cabral, Horacio; Kumagai, Michiaki; Nomoto, Takahiro; Aoki, Ichio; Terada, Yasuko; Kishimura, Akihiro; Nishiyama, Nobuhiro; Kataoka, Kazunori

    2014-01-28

    Organic-inorganic hybrid nanoparticles with calcium phosphate (CaP) core and PEGylated shell were developed to incorporate magnetic resonance imaging (MRI) contrast agent diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) for noninvasive diagnosis of solid tumors. A two-step preparation method was applied to elaborate hybrid nanoparticles with a z-average hydrodynamic diameter about 80nm, neutral surface ?-potential and high colloidal stability in physiological environments by self-assembly of poly(ethylene glycol)-b-poly(aspartic acid) block copolymer, Gd-DTPA, and CaP in aqueous solution, followed with hydrothermal treatment. Incorporation into the hybrid nanoparticles allowed Gd-DTPA to show significant enhanced retention ratio in blood circulation, leading to high accumulation in tumor positions due to enhanced permeability and retention (EPR) effect. Moreover, Gd-DTPA revealed above 6 times increase of relaxivity in the nanoparticle system compared to free form, and eventually, selective and elevated contrast enhancements in the tumor positions were observed. These results indicate the high potential of Gd-DTPA-loaded PEGylated CaP nanoparticles as a novel contrast agent for noninvasive cancer diagnosis. PMID:24211705

  20. Colorimetric cholesterol sensor based on peroxidase like activity of zinc oxide nanoparticles incorporated carbon nanotubes.

    PubMed

    Hayat, Akhtar; Haider, Waqar; Raza, Yousuf; Marty, Jean Louis

    2015-10-01

    A sensitive and selective colorimetric method based on the incorporation of zinc oxide nanoparticles (ZnO NPs) on the surface of carbon nanotubes (CNTs) was shown to posses synergistic peroxidase like activity for the detection of cholesterol. The proposed nanocomposite catalyzed the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) in the presence of hydrogen peroxide (H2O2) to produce a green colored product which can be monitored at 405 nm. H2O2 is the oxidative product of cholesterol in the presence of cholesterol oxidase. Therefore, the oxidation of cholesterol can be quantitatively related to the colorimetric response by combining these two reactions. Under the optimal experimental conditions, the colorimetric response was proportional to the concentration of cholesterol in the range of 0.5-500 nmol/L, with a detection limit of 0.2 nmol/L. The applicability of the proposed assays was demonstrated for the determination of cholesterol in milk powder samples with good recovery results. PMID:26078143

  1. Incorporation of functionalized gold nanoparticles into nanofibers for enhanced attachment and differentiation of mammalian cells

    PubMed Central

    2012-01-01

    Background Electrospun nanofibers have been widely used as substrata for mammalian cell culture owing to their structural similarity to natural extracellular matrices. Structurally consistent electrospun nanofibers can be produced with synthetic polymers but require chemical modification to graft cell-adhesive molecules to make the nanofibers functional. Development of a facile method of grafting functional molecules on the nanofibers will contribute to the production of diverse cell type-specific nanofiber substrata. Results Small molecules, peptides, and functionalized gold nanoparticles were successfully incorporated with polymethylglutarimide (PMGI) nanofibers through electrospinning. The PMGI nanofibers functionalized by the grafted AuNPs, which were labeled with cell-adhesive peptides, enhanced HeLa cell attachment and potentiated cardiomyocyte differentiation of human pluripotent stem cells. Conclusions PMGI nanofibers can be functionalized simply by co-electrospinning with the grafting materials. In addition, grafting functionalized AuNPs enable high-density localization of the cell-adhesive peptides on the nanofiber. The results of the present study suggest that more cell type-specific synthetic substrata can be fabricated with molecule-doped nanofibers, in which diverse functional molecules are grafted alone or in combination with other molecules at different concentrations. PMID:22686683

  2. HemoglobinAlbumin Cluster Incorporating a Pt Nanoparticle: Artificial O2 Carrier with Antioxidant Activities

    PubMed Central

    Hosaka, Hitomi; Haruki, Risa; Yamada, Kana; Bttcher, Christoph; Komatsu, Teruyuki

    2014-01-01

    A covalent coreshell structured protein cluster composed of hemoglobin (Hb) at the center and human serum albumins (HSA) at the periphery, Hb-HSAm, is an artificial O2 carrier that can function as a red blood cell substitute. Here we described the preparation of a novel Hb-HSA3 cluster with antioxidant activities and its O2 complex stable in aqueous H2O2 solution. We used an approach of incorporating a Pt nanoparticle (PtNP) into the exterior HSA unit of the cluster. A citrate reduced PtNP (1.8 nm diameter) was bound tightly within the cleft of free HSA with a binding constant (K) of 1.1107 M?1, generating a stable HSA-PtNP complex. This platinated protein showed high catalytic activities for dismutations of superoxide radical anions (O2) and hydrogen peroxide (H2O2), i.e., superoxide dismutase and catalase activities. Also, Hb-HSA3 captured PtNP into the external albumin unit (K?=?1.1107 M?1), yielding an Hb-HSA3(PtNP) cluster. The association of PtNP caused no alteration of the protein surface net charge and O2 binding affinity. The peripheral HSA-PtNP shell prevents oxidation of the core Hb, which enables the formation of an extremely stable O2 complex, even in H2O2 solution. PMID:25310133

  3. Preparation,-Characterization and Anti-Glioma Effects of Docetaxel-Incorporated Albumin-Lipid Nanoparticles.

    PubMed

    Gao, Huile; Cao, Shijie; Yang, Zhi; Zhang, Shuang; Zhang, Qizhi; Jiang, Xinguo

    2015-12-01

    Poor aqueous solubility is a serious problem for most chemotherapeutics. Docetaxel (DTX), an inhibitor of microtubule depolymerization, is frequently used to treat many malignancies. However, the surfactant used in its commercial preparation (Taxotere) has proven problematic in clinical use because it has been associated with several side effects. By utilizing the high DTX-loading property of albumin, a new formulation, DTX-incorporated albumin-lipid nanoparticles (DNPs), was prepared and evaluated. DTX was bound to albumin in vitro and dispersed by egg yolk lecithin. The DNP particle size was 110.1 nm, while the average DNP zeta potential was -2.95 mV. The median lethal dose of DNPs was 180.6 mg/kg, which was 75.3% higher than that of Taxotere. DNPs could effectively inhibit the proliferation of several cell lines and induce cell apoptosis. In vivo imaging suggested that DNPs localize to and accumulate at the glioma site, which is likely due to the enhanced permeation and retention effects of DNPs. These pharmacological experiments further confirmed that DNPs can inhibit tumor growth, prolong the median survival time of mice with gliomas and induce higher levels of apoptosis. In conclusion, this novel formulation of DTX (DNPs) displayed lower toxicity and a superior anti-glioma effect relative to standard DTX preparations. PMID:26510308

  4. Designer nanoparticles: Incorporating size, shape, and triggered release into nanoscale drug carriers

    PubMed Central

    Caldorera-Moore, Mary; Guimard, Nathalie; Shi, Li; Roy, Krishnendu

    2009-01-01

    Importance of the field Although significant progress has been made in delivering therapeutic agents through micro and nanocarriers, precise control over in vivo biodistribution and disease-responsive drug release has been difficult to achieve. This is critical for the success of next generation drug delivery devices, since newer drugs, designed to interfere with cellular functions, must be efficiently and specifically delivered to diseased cells. The major constraint in achieving this has been our limited repertoire of particle synthesis methods, especially at the nanoscale. Recent developments in generating shape-specific nanocarriers and the potential to combine stimuli-responsive release with nanoscale delivery devices show great promise in overcoming these limitations. Areas covered in this review Here we discuss how recent advancements in fabrication technology allow synthesis of highly monodisperse, stimuli-responsive, drug-carrying nanoparticles of precise geometries. We also review how particle properties, specifically shape and stimuli responsiveness, affect biodistribution, cellular uptake, and drug release. What the reader will gain The reader is introduced to recent developments in intelligent drug nanocarriers and new nanofabrication approaches that can be combined with disease-responsive biomaterials. This will provide insight into the importance of controlling particle geometry and incorporating stimuli responsive materials into drug delivery. PMID:20331355

  5. Triamcinolone acetonide nanoparticles incorporated in thermoreversible gels for age-related macular degeneration.

    PubMed

    Hirani, Anjali; Grover, Aditya; Lee, Yong W; Pathak, Yashwant; Sutariya, Vijaykumar

    2016-02-01

    Age-related macular degeneration (AMD) is one of the leading causes of blindness in the US affecting millions yearly. It is characterized by intraocular neovascularization, inflammation and retinal damage which can be ameliorated through intraocular injections of glucocorticoids. However, the complications that arise from repetitive injections as well as the difficulty posed by targeting the posterior segment of the eye make this interesting territory for the development of novel drug delivery systems (DDS). In the present study, we described the development of a DDS composed of triamcinolone acetonide-encapsulated PEGylated PLGA nanoparticles (NP) incorporated into PLGA-PEG-PLGA thermoreversible gel and its use against VEGF expression characteristic of AMD. We found that the NP with mean size of 208 ± 1.0 nm showed uniform size distribution and exhibited sustained release of the drug. We also demonstrated that the polymer can be injected as a solution and transition to a gel phase based on the biological temperature of the eye. Additionally, the proposed DDS was non-cytotoxic to ARPE-19 cells and significantly reduced VEGF expression by 43.5 ± 3.9% as compared to a 1.53 ± 11.1% reduction with triamcinolone. These results suggest the proposed DDS will contribute to the development of novel therapeutic strategies for AMD. PMID:25259682

  6. On the incorporation of Rhodamine B and 2?,7?-dichlorofluorescein dyes in silica: Synthesis of fluorescent nanoparticles

    NASA Astrophysics Data System (ADS)

    Gomes, Elis C. C.; de Carvalho, Idalina M. M.; Digenes, Izaura C. N.; de Sousa, Eduardo H. S.; Longhinotti, Elisane

    2014-05-01

    The present paper reports the incorporation of 2?,7?-dichlorofluorescein (DCF) and Rhodamine B (RhB) dyes in silica nanoparticles by using the Stber's method with some modifications. Based on infrared and electronic spectroscopies, these dyes were successfully incorporated resulting in fluorescent nanomaterials of an average size of 80 nm. A composite fluorescent nanomaterial containing both dyes was also synthesized and showed the occurrence of Frster resonant energy transfer process (FRET) with the average distance between the donor (DCF) and acceptor (RhB) of 3.6 nm. Furthermore, these fluorescent nanoparticles were modified with folic acid producing nanomaterials whose Zeta potential values were in the range of -2 to -13 mV. These values are consistent with the low dispersivity observed by TEM micrographs. Altogether, these suitable properties can lead to the development of nanomaterials for cancer bioimaging and drug release.

  7. Mechanisms Underlying Apoptosis-Inducing Effects of Kaempferol in HT-29 Human Colon Cancer Cells

    PubMed Central

    Lee, Hyun Sook; Cho, Han Jin; Yu, Rina; Lee, Ki Won; Chun, Hyang Sook; Park, Jung Han Yoon

    2014-01-01

    We previously noted that kaempferol, a flavonol present in vegetables and fruits, reduced cell cycle progression of HT-29 cells. To examine whether kaempferol induces apoptosis of HT-29 cells and to explore the underlying molecular mechanisms, cells were treated with various concentrations (0–60 μmol/L) of kaempferol and analyzed by Hoechst staining, Annexin V staining, JC-1 labeling of the mitochondria, immunoprecipitation, in vitro kinase assays, Western blot analyses, and caspase-8 assays. Kaempferol increased chromatin condensation, DNA fragmentation and the number of early apoptotic cells in HT-29 cells in a dose-dependent manner. In addition, kaempferol increased the levels of cleaved caspase-9, caspase-3 and caspase-7 as well as those of cleaved poly (ADP-ribose) polymerase. Moreover, it increased mitochondrial membrane permeability and cytosolic cytochrome c concentrations. Further, kaempferol decreased the levels of Bcl-xL proteins, but increased those of Bik. It also induced a reduction in Akt activation and Akt activity and an increase in mitochondrial Bad. Additionally, kaempferol increased the levels of membrane-bound FAS ligand, decreased those of uncleaved caspase-8 and intact Bid and increased caspase-8 activity. These results indicate that kaempferol induces the apoptosis of HT-29 cells via events associated with the activation of cell surface death receptors and the mitochondrial pathway. PMID:24549175

  8. Studies on the interactions of kaempferol to calcineurin by spectroscopic methods and docking.

    PubMed

    Lei, Hong; Qi, Yao; Jia, Zhi-Guang; Lin, Wei-Lin; Wei, Qun

    2009-08-01

    Kaempferol, in our previous study, was a new immunosuppressant on calcineurin (CN), the Ca(2+)/calmodulin (CaM)-dependent protein phosphatase. Here, we examined the interactions of kaempferol with CN by fluorescence spectroscopy (FS), circular dichroism spectroscopy (CD) and docking. Data of kaempferol with CN catalytic subunit (CN A) and its truncated mutant CNAa obtained by FS method showed that the binding stoichiometry of kaempferol/CN A was 1:1, catalytic domain of CN A was the concrete domain for kaempferol binding while other domains contributed a lot to this binding. Distances from kaempferol to each tryptophan (Trp) in CN A by energy transfer experiments and the subsequent docking study interestingly provided the same binding sites for kaempferol, which all located in the non-active site area of CN A catalytic domain, also consisted with our previous conclusion from CN activity assay. Furthermore, CD results showed a much tighter structure of CN A for the inhibitor binding; on the other hand, presence of Ca(2+) and Mn(2+) decreased kaempferol binding on CN A. PMID:19439201

  9. Kaempferol Isolated from Nelumbo nucifera Inhibits Lipid Accumulation and Increases Fatty Acid Oxidation Signaling in Adipocytes.

    PubMed

    Lee, Bonggi; Kwon, Misung; Choi, Jae Sue; Jeong, Hyoung Oh; Chung, Hae Young; Kim, Hyeung-Rak

    2015-12-01

    Stamens of Nelumbo nucifera Gaertn have been used as a Chinese medicine due to its antioxidant, hypoglycemic, and antiatherogenic activity. However, the effects of kaempferol, a main component of N. nucifera, on obesity are not fully understood. We examined the effect of kaempferol on adipogenesis and fatty acid oxidation signaling pathways in 3T3-L1 adipocytes. Kaempferol reduced cytoplasmic triglyceride (TG) accumulation in dose and time-dependent manners during adipocyte differentiation. Accumulation of TG was rapidly reversed by retrieving kaempferol treatment. Kaempferol broadly decreased mRNA or protein levels of adipogenic transcription factors and their target genes related to lipid accumulation. Kaempferol also suppressed glucose uptake and glucose transporter GLUT4 mRNA expression in adipocytes. Furthermore, protein docking simulation suggests that Kaempferol can directly bind to and activate peroxisome proliferator-activated receptor (PPAR)-α by forming hydrophobic interactions with VAL324, THR279, and LEU321 residues of PPARα. The binding affinity was higher than a well-known PPARα agonist fenofibrate. Consistently, mRNA expression levels of PPARα target genes were increased. Our study indicates while kaempferol inhibits lipogenic transcription factors and lipid accumulation, it may bind to PPARα and stimulate fatty acid oxidation signaling in adipocytes. PMID:26280739

  10. Modulation of P-glycoprotein-mediated resistance by kaempferol derivatives isolated from Zingiber zerumbet.

    PubMed

    Chung, Soo Yeon; Jang, Dae Sik; Han, Ah-Reum; Jang, Jung Ok; Kwon, Youngjoo; Seo, Eun-Kyoung; Lee, Hwa Jeong

    2007-06-01

    This study examined the effects of the kaempferol derivatives extracted from Zingiber zerumbet on the accumulation and efflux of [(3)H]-daunomycin (DNM) in P-glycoprotein (P-gp) overexpressing multidrug resistant (MDR) human breast cancer cells, MCF-7/ADR. Of six kaempferol derivatives extracted from Z. zerumbet, kaempferol-3-O-methyl ether (1) and kaempferol-3,4'-O-dimethyl ether (2) showed a potent P-gp inhibitory effect as great as verapamil, a well-known P-gp inhibitor. The P-gp inhibitory activity of these two compounds was through a 3-fold increase of the level of [(3)H]-DNM accumulation and a decrease of P-gp-mediated efflux. These results suggest that the kaempferol derivative components of Z. zerumbet can be used as a scaffold for developing agents that reverse P-gp-mediated MDR in human cancer chemotherapy. PMID:17335117

  11. Copper Nanoparticle-Incorporated Carbon Fibers as Free-Standing Anodes for Lithium-Ion Batteries.

    PubMed

    Han, Pan; Yuan, Tao; Yao, Long; Han, Zhuo; Yang, Junhe; Zheng, Shiyou

    2016-12-01

    Copper-incorporated carbon fibers (Cu/CF) as free-standing anodes for lithium-ion batteries are prepared by electrospinning technique following with calcination at 600, 700, and 800 °C. The structural properties of materials are characterized by X-ray diffraction (XRD), Raman, thermogravimetry (TGA), scanning electron microscopy (SEM), transmission electron microscope (TEM), and energy dispersive X-ray spectrometry (EDS). It is found that the Cu/CF composites have smooth, regular, and long fibrous morphologies with Cu nanoparticles uniformly dispersed in the carbon fibers. As free-standing anodes, the unique structural Cu/CF composites show stable and high reversible capacities, together with remarkable rate and cycling capabilities in Li-ion batteries. The Cu/CF calcined at 800 °C (Cu/CF-800) has the highest charge/discharge capacities, long-term stable cycling performance, and excellent rate performance; for instance, the Cu/CF-800 anode shows reversible charge/discharge capacities of around 800 mAh g(-1) at a current density of 100 mA g(-1) with stable cycling performance for more than 250 cycles; even when the current density increases to 2 A g(-1), the Cu/CF-800 anode can still deliver a capacity of 300 mAh g(-1). This excellent electrochemical performance is attributed to the special 1D structure of Cu/CF composites, the enhanced electrical conductivity, and more Li(+) active positions by Cu nanoinclusion. PMID:27033848

  12. A Au nanoparticle-incorporated sponge as a versatile transmission surface-enhanced Raman scattering substrate.

    PubMed

    Shin, Kayeong; Chung, Hoeil

    2015-08-01

    We report a sponge-based transmission surface-enhanced Raman scattering (TSERS) substrate that combines the bulk sampling capabilities of a transmission measurement to improve the quantitative representation of sample concentration with several sponge properties useful for analysis such as fast sample uptake, easy sample enrichment, and a stable polymeric structure. Among nine commercially available sponges made of different materials, a melamine sponge was ultimately selected for this study because it provided the fastest sample uptake and a low background Raman signal. Simultaneously, the amino groups and three-nitrogen hybrid rings in its structure could easily hold Au nanoparticles (AuNPs) inside the sponge. AuNP-incorporated sponges (AuNP sponges) were prepared by simply soaking a melamine sponge in a AuNP solution; these sponges were initially used to measure 4-nitrobenzenethiol (4-NBT) samples with different concentrations in order to evaluate their ability as TSERS substrates. The intensities of the 4-NBT peaks clearly varied according to changes in the concentration, and the relative standard deviation (RSD) of the peak intensity estimated by the measurements of five independently prepared AuNP sponges was 10.0%. Sample enrichment was easily completed by repeated suctioning of the sample into the AuNP sponges followed by depletion of the solvent, so three-time enrichment doubled the intensity. Furthermore, paraquat samples were prepared in diverse matrices (de-ionized water, tap water, river water, and orange juice) and measured using the AuNP sponges. The paraquat peaks were clearly observed from these samples and their peak intensities became smaller with the increased compositional complexity of the matrices. Our overall results demonstrate that the TSERS sponge substrates are easy to prepare and practically versatile for SERS analysis of diverse samples. PMID:26079472

  13. Effect of silver nanoparticles incorporated with samarium-doped magnesium tellurite glasses

    NASA Astrophysics Data System (ADS)

    Yusoff, N. M.; Sahar, M. R.

    2015-01-01

    Silver nanoparticles (Ag NPs) are incorporated in samarium doped tellurite glass of a composition (89-x)TeO2-10MgO-1Sm2O3-xAgCl, where 0.0?x?0.6 mol%, by a melt quenching technique. It is found that all the glasses are amorphous in nature, and the existence of Ag NPs with an average size of 16.94 nm is confirmed by Transmission Electron Microscopy. Meanwhile, their physical properties such as glass density, molar volume and ionic packing density are computed utilizing the normal method. The density and ionic packing density are observed to decrease with increasing Ag NPs, but increase when the Ag NPs are beyond 0.2 mol%. On the other hand, the molar volume behaves exactly opposite to the increase in Ag NPs content. It decreases when the Ag NPs content value is more than 0.2 mol%. The optical energy band gap and Urbach energy are evaluated from the absorption spectra in the range of 200-900 nm at room temperature. It is also observed that the direct and indirect optical energy band gaps reduce with Ag NPs content, but enhance when the Ag NPs are beyond 0.2 mol%. Meanwhile, the Urbach energy is found to increase as the Ag NPs content is increased but decreases when Ag NPs is 0.2 mol%. The refractive index is deduced from indirect optical energy band gap. Meanwhile, molar refraction and electronic polarizability have been calculated from the Lorentz-Lorentz relation. Refractive index and electronic polarizability are also observed to raise with Ag NPs content, but drop off when Ag NPs content is more than 0.2 mol%. In this paper, all properties are discussed with respect to the Ag NPs concentration.

  14. Palladium Nanoparticle Incorporated Porous Activated Carbon: Electrochemical Detection of Toxic Metal Ions.

    PubMed

    Veerakumar, Pitchaimani; Veeramani, Vediyappan; Chen, Shen-Ming; Madhu, Rajesh; Liu, Shang-Bin

    2016-01-20

    A facile method has been developed for fabricating selective and sensitive electrochemical sensors for the detection of toxic metal ions, which invokes incorporation of palladium nanoparticles (Pd NPs) on porous activated carbons (PACs). The PACs, which were derived from waste biomass feedstock (fruit peels), possess desirable textural properties and porosities favorable for dispersion of Pd NPs (ca. 3-4 nm) on the graphitic PAC substrate. The Pd/PAC composite materials so fabricated were characterized by a variety of different techniques, such as X-ray diffraction, field-emission transmission electron microscopy, gas physisorption/chemisorption, thermogravimetric analysis, and Raman, Fourier-transform infrared, and X-ray photon spectroscopies. The Pd/PAC-modified glassy carbon electrodes (GCEs) were exploited as electrochemical sensors for the detection of toxic heavy metal ions, viz., Cd(2+), Pb(2+), Cu(2+), and Hg(2+), which showed superior performances for both individual as well as simultaneous detections. For simultaneous detection of Cd(2+), Pb(2+), Cu(2+), and Hg(2+), a linear response in the ion concentration range of 0.5-5.5, 0.5-8.9, 0.5-5.0, and 0.24-7.5 μM, with sensitivity of 66.7, 53.8, 41.1, and 50.3 μA μM(-1) cm(-2), and detection limit of 41, 50, 66, and 54 nM, respectively, was observed. Moreover, the Pd/PAC-modified GCEs also show perspective applications in detection of metal ions in real samples, as illustrated in this study for a milk sample. PMID:26700093

  15. Anthocyanin indexes, quercetin, kaempferol, and myricetin concentration in leaves and fruit of Abutilon theophrasti Medik. genetic resources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anthocyanin indexes, quercetin, kaempferol, and myricetin may provide industry with potential new medicines or nutraceuticals. Velvetleaf (Abutilon theophrasti Medik) leaves from 42 accessions were analyzed for anthocyanin indexes while both leaves and fruit were used for quercetin, kaempferol, and ...

  16. Quercetin, kaempferol, myricetin, and fatty acid content among several Hibiscus sabdariffa accession calyces based on maturity in a greenhouse

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavonols including quercetin, kaempferol, myricetin, and fatty acids in plants have many useful health attributes including antioxidants, cholesterol lowering, and cancer prevention. Six accessions of roselle, Hibiscus sabdariffa calyces were evaluated for quercetin, kaempferol, and myricetin conte...

  17. Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of apolipoprotein E deficient mice

    SciTech Connect

    Xiao, Hong-Bo; Lu, Xiang-Yang; Sun, Zhi-Liang; Zhang, Heng-Bo

    2011-12-15

    Recent studies show that osteopontin (OPN) and its receptor cluster of differentiation 44 (CD44) are two pro-inflammatory cytokines contributing to the development of atherosclerosis. The objective of this study was to explore the inhibitory effect of kaempferol, a naturally occurring flavonoid compound, on atherogenesis and the mechanisms involved. The experiments were performed in aorta and plasma from C57BL/6J control and apolipoprotein E-deficient (ApoE{sup -/-}) mice treated or not with kaempferol (50 or 100 mg/kg, intragastrically) for 4 weeks. Kaempferol treatment decreased atherosclerotic lesion area, improved endothelium-dependent vasorelaxation, and increased the maximal relaxation value concomitantly with decrease in the half-maximum effective concentration, plasma OPN level, aortic OPN expression, and aortic CD44 expression in ApoE{sup -/-} mice. In addition, treatment with kaempferol also significantly decreased reactive oxygen species production in mice aorta. The present results suggest that kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. -- Graphical abstract: Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. Highlights: Black-Right-Pointing-Pointer OPN-CD44 pathway plays a critical role in the development of atherosclerosis. Black-Right-Pointing-Pointer We examine lesion area, OPN and CD44 changes after kaempferol treatment. Black-Right-Pointing-Pointer Kaempferol treatment decreased atherosclerotic lesion area in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol treatment decreased aortic OPN and CD44 expressions in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis.

  18. Incorporation of essential oils and nanoparticles in pullulan films to control foodborne pathogens on meat and poultry products.

    PubMed

    Morsy, Mohamed K; Khalaf, Hassan H; Sharoba, Ashraf M; El-Tanahi, Hassan H; Cutter, Catherine N

    2014-04-01

    The incorporation of essential oils and nanotechnology into edible films has the potential to improve the microbiological safety of foods. The aim of this study was to evaluate the effectiveness of pullulan films containing essential oils and nanoparticles against 4 foodborne pathogens. Initial experiments using plate overlay assays demonstrated that 2% oregano essential oil was active against Staphylococcus aureus and Salmonella Typhimurium, whereas Listeria monocytogenes and Escherichia coli O157:H7 were not inhibited. Two percent rosemary essential oil was active against S. aureus, L. monocytogenes, E. coli O157:H7, and S. Typhimurium, when compared with 1%. Zinc oxide nanoparticles at 110 nm were active against S. aureus, L. monocytogenes, E. coli O157:H7, and S. Typhimurium, when compared with 100 or 130 nm. Conversely, 100 nm silver (Ag) nanoparticles were more active against S. aureus than L. monocytogenes. Using the results from these experiments, the compounds exhibiting the greatest activity were incorporated into pullulan films and found to inhibit all or some of the 4 pathogens in plate overlay assays. In challenge studies, pullulan films containing the compounds effectively inhibited the pathogens associated with vacuum packaged meat and poultry products stored at 4 C for up to 3 wk, as compared to control films. Additionally, the structure and cross-section of the films were evaluated using electron microscopy. The results from this study demonstrate that edible films made from pullulan and incorporated with essential oils or nanoparticles may improve the safety of refrigerated, fresh or further processed meat and poultry products. PMID:24621108

  19. Covalent Incorporation of SiO2 Nanoparticles in CO2-Based Copolymers: Synthesis, Characterization, Morphology and Property Studies.

    PubMed

    Tran, Thi Nga; Mai, Thanh Binh; Bach, Long Giang; Islam, Md Rafiqul; Gal, Yeong Soon; Lim, Kwon Taek

    2015-01-01

    A new strategy has been developed for covalent incorporation of SiO2 nanoparticles (N-'s) in the CO2-based copolymer, poly(propylene carbonate-co-propylene oxide) (poly(PC-co-PO)). The poly(PC-co-PO)-g-SiO2 nanocomposites was prepared by the combination of epoxy-CO2 ring-opening polymerization and the condensation reaction of chloride and hydroxyl groups of the polymer and the SiO2 surface. FT-IR and NMR were employed for the characterization of the copolymers as well as nanocomposites. A uniform and spherical core-shell structure of poly(PC-co-PO)-g-SiO2 nanocomposites was demonstrated from TEM and SEM images. An improved thermal property of the polymer matrix with incorporating SiO2 nanoparticles was revealed by TGA study. The grafting of poly(PC-co-PO) considerably prevented the aggregation and improved the dispersibility of SiO2 nanoparticles in toluene. PMID:26328378

  20. Enhancement of polymer endurance to UV light by incorporation of semiconductor nanoparticles

    NASA Astrophysics Data System (ADS)

    Rudko, Galyna; Kovalchuk, Andrii; Fediv, Volodymyr; Chen, Weimin M.; Buyanova, Irina A.

    2015-02-01

    Improvement of polyvinyl alcohol stability against ultraviolet (UV) illumination is achieved by introducing cadmium sulfide (CdS) nanoparticles into the polymeric matrix. Enhancement of stability is analyzed by optical characterization methods. UV protection is achieved by diminishing the probability of photo-activated formation of defects in polymer. The sources of polymer protection are the lowering of the efficiency of polymer excitation via partial absorption of incident light by the embedded nanoparticles as well as the de-excitation of the macromolecules that have already absorbed UV quanta via energy drain to nanoparticles. Within the nanoparticles, the energy is either dissipated by conversion to the thermal energy or reemitted as visible-range photoluminescence quanta.

  1. Antimicrobial properties of poly (methyl methacrylate) acrylic resins incorporated with silicon dioxide and titanium dioxide nanoparticles on cariogenic bacteria

    PubMed Central

    Sodagar, Ahmad; Khalil, Soufia; Kassaee, Mohammad Zaman; Shahroudi, Atefe Saffar; Pourakbari, Babak; Bahador, Abbas

    2016-01-01

    Aim: To assess the effects of adding nano-titanium dioxide (nano-TiO2) and nano-silicon dioxide (nano-SiO2) and their mixture to poly (methyl methacrylate) (PMMA) to induce antimicrobial activity in acrylic resins. Materials and Methods: Acrylic specimens in size of 20 mm × 20 mm × 1 mm of 0.5% and 1% of nano-TiO2 (21 nm) and nano-SiO2 (20 nm) and their mixture (TiO2/SiO2 nanoparticles) (1:1 w/w) were prepared from the mixture of acrylic liquid containing nanoparticles and acrylic powder. To obtain 0.5% and 1% concentration, 0.02 g and 0.04 g of the nanoparticles was added to each milliliter of the acrylic monomer, respectively. Antimicrobial properties of six specimens of these preparations, as prepared, were assessed against planktonic Lactobacillus acidophilus and Streptococcus mutans at 0, 15, 30, 45, 60, 75, and 90 min follow-up by broth dilution assay. The specimens of each group were divided into three subgroups: Dark, daylight, or ultraviolet A (UVA). The percent of bacterial reduction is found out from the counts taken at each time point. Statistical Analysis: Data were analyzed using one-way analysis of variance and Tukey's post hoc analysis. Results: Exposure to PMMA containing the nanoparticles reduced the bacterial count by 3.2–99%, depending on the nanoparticles, bacterial types, and light conditions. Planktonic cultures of S. mutans and L. acidophilus exposed to PMMA containing 1% of TiO2/SiO2 nanoparticles showed a significant decrease (P < 0.001) (98% and 99%, respectively) in a time-dependent manner under UVA. The S. mutans and L. acidophilus counts did not significantly decrease in PMMA containing 0.5% nano-TiO2 and PMMA containing 0.5% nano-SiO2 in the dark. No statistically significant reduction (P > 0.05) was observed in the counts of S. mutans and L. acidophilus in PMMA without the nanoparticles exposed to UVA. Conclusions: PMMA resins incorporated with TiO2/SiO2 nanoparticles showed strong antimicrobial activity against the cariogenic bacteria. PMID:26998471

  2. Incorporation of copper nanoparticles into paper for point-of-use water purification.

    PubMed

    Dankovich, Theresa A; Smith, James A

    2014-10-15

    As a cost-effective alternative to silver nanoparticles, we have investigated the use of copper nanoparticles in paper filters for point-of-use water purification. This work reports an environmentally benign method for the direct in situ preparation of copper nanoparticles (CuNPs) in paper by reducing sorbed copper ions with ascorbic acid. Copper nanoparticles were quickly formed in less than 10min and were well distributed on the paper fiber surfaces. Paper sheets were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic absorption spectroscopy. Antibacterial activity of the CuNP sheets was assessed for by passing Escherichia coli bacteria suspensions through the papers. The effluent was analyzed for viable bacteria and copper release. The CuNP papers with higher copper content showed a high bacteria reduction of log 8.8 for E. coli. The paper sheets containing copper nanoparticles were effective in inactivating the test bacteria as they passed through the paper. The copper levels released in the effluent water were below the recommended limit for copper in drinking water (1ppm). PMID:25014431

  3. Incorporation of copper nanoparticles into paper for point-of-use water purification

    PubMed Central

    Smith, James A.

    2014-01-01

    As a cost-effective alternative to silver nanoparticles, we have investigated the use of copper nanoparticles in paper filters for point-of-use water purification. This work reports an environmentally benign method for the direct in situ preparation of copper nanoparticles (CuNPs) in paper by reducing sorbed copper ions with ascorbic acid. Copper nanoparticles were quickly formed in less than 10 minutes and were well distributed on the paper fiber surfaces. Paper sheets were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic absorption spectroscopy. Antibacterial activity of the CuNP sheets was assessed for by passing Escherichia coli bacteria suspensions through the papers. The effluent was analyzed for viable bacteria and copper release. The CuNP papers with higher copper content showed a high bacteria reduction of log 8.8 for E. coli. The paper sheets containing copper nanoparticles were effective in inactivating the test bacteria as they passed through the paper. The copper levels released in the effluent water were below the recommended limit for copper in drinking water (1 ppm). PMID:25014431

  4. Large sensitivity enhancement in semiconducting organic field effect transistor sensors through incorporation of ultra-fine platinum nanoparticles

    NASA Astrophysics Data System (ADS)

    Zheng, Haisheng; Ramalingam, Balavinayagam; Korampally, Venumadhav; Gangopadhyay, Shubhra

    2013-11-01

    We report remarkable improvement in sensitivity of pentacene-based field effect transistor devices towards trace nitro-aromatic explosive vapors through the incorporation of high density, sub-2 nm platinum nanoparticles (NPs) within these structures. Exploiting the unique electronic properties of these NPs, we have demonstrated a detection limit of 56.6 parts per billion of 2,4-dinitrotoluene (DNT) vapor while control samples without any embedded NPs showed no observable sensitivity to DNT vapor. We attribute this remarkable enhancement in sensitivity to the ability of these NPs to function as discrete nodes, participating in the charge transfer with adsorbed nitro-aromatic molecules.

  5. Large sensitivity enhancement in semiconducting organic field effect transistor sensors through incorporation of ultra-fine platinum nanoparticles

    SciTech Connect

    Zheng, Haisheng; Ramalingam, Balavinayagam; Korampally, Venumadhav; Gangopadhyay, Shubhra

    2013-11-04

    We report remarkable improvement in sensitivity of pentacene-based field effect transistor devices towards trace nitro-aromatic explosive vapors through the incorporation of high density, sub-2 nm platinum nanoparticles (NPs) within these structures. Exploiting the unique electronic properties of these NPs, we have demonstrated a detection limit of 56.6 parts per billion of 2,4-dinitrotoluene (DNT) vapor while control samples without any embedded NPs showed no observable sensitivity to DNT vapor. We attribute this remarkable enhancement in sensitivity to the ability of these NPs to function as discrete nodes, participating in the charge transfer with adsorbed nitro-aromatic molecules.

  6. Quantum confinement in GaAs nanoparticles incorporated in SiO2 matrix.

    NASA Astrophysics Data System (ADS)

    Bautista-Hernandez, A.; Meza-Montes, L.; Pal, U.; Garcia-Serrano, J.; Koshizaki, N.; Sasaki, T.

    2000-03-01

    Using the Empirical Pseudopotential Method and applying the Ramakrishna and Friesner approximation [1], the band gap is calculated for GaAs nanoparticles. Theoretically calculated results are compared with the experimentally obtained band gap values extracted from the optical absorption measurements on the GaAs nanoparticles embedded in SiO2 matrix. The nanocomposite materials were grown by r. f. sputtering. Transmission electron microscope images were used to determine the size distribution of GaAs nanoparticles. Size distribution broadening and the discretization of energy levels are applied to correlate the theoretical results with the experimentally obtained data values. A good agreement between theory and experiment is obtained. [1] Ramakrishna, M. V. and Friesner, R. A. Phys. Rev. Lett. 67 (1991) 629.

  7. Microwave-assisted incorporation of silver nanoparticles in paper for point-of-use water purification.

    PubMed

    Dankovich, Theresa A

    2014-08-01

    This work reports an environmentally benign method for the in situ preparation of silver nanoparticles (AgNPs) in paper using microwave irradiation. Through thermal evaporation, microwave heating with an excess of glucose relative to the silver ion precursor yields nanoparticles on the surface of cellulose fibers within three minutes. Paper sheets were characterized by electron microscopy, UV-Visible reflectance spectroscopy, and atomic absorption spectroscopy. Antibacterial activity and silver release from the AgNP sheets were assessed for model Escherichia coli and Enterococci faecalis bacteria in deionized water and in suspensions that also contained with various influent solution chemistries, i.e. with natural organic matter, salts, and proteins. The paper sheets containing silver nanoparticles were effective in inactivating the test bacteria as they passed through the paper. PMID:25400935

  8. Microwave-assisted incorporation of silver nanoparticles in paper for point-of-use water purification

    PubMed Central

    Dankovich, Theresa A.

    2014-01-01

    This work reports an environmentally benign method for the in situ preparation of silver nanoparticles (AgNPs) in paper using microwave irradiation. Through thermal evaporation, microwave heating with an excess of glucose relative to the silver ion precursor yields nanoparticles on the surface of cellulose fibers within three minutes. Paper sheets were characterized by electron microscopy, UV-Visible reflectance spectroscopy, and atomic absorption spectroscopy. Antibacterial activity and silver release from the AgNP sheets were assessed for model Escherichia coli and Enterococci faecalis bacteria in deionized water and in suspensions that also contained with various influent solution chemistries, i.e. with natural organic matter, salts, and proteins. The paper sheets containing silver nanoparticles were effective in inactivating the test bacteria as they passed through the paper. PMID:25400935

  9. Stabilization and cellular delivery of chitosan-polyphosphate nanoparticles by incorporation of iron.

    PubMed

    Giacalone, Giovanna; Hillaireau, Herv; Capiau, Pauline; Chacun, Hlne; Reynaud, Franceline; Fattal, Elias

    2014-11-28

    Chitosan (CS) nanoparticles are typically obtained by complexation with tripolyphosphate (TPP) ions, or more recently using triphosphate group-containing drugs such as adenosine triphosphate (ATP). ATP is an active molecule we aim to deliver in order to restore its depletion in macrophages, when associated with their death leading to plaque rupture in atherosclerotic lesions. Despite high interest in CS nanoparticles for drug delivery, due to the biodegradability of CS and to the ease of the preparation process, these systems tend to readily disintegrate when diluted in physiological media. Some stabilization strategies have been proposed so far but they typically involve the addition of a coating agent or chemical cross-linkers. In this study, we propose the complexation of CS with iron ions prior to nanoparticle formation as a strategy to improve the carrier stability. This can be achieved thanks to the ability of iron to strongly bind both chitosan and phosphate groups. Nanoparticles were obtained from either TPP or ATP and chitosan-iron (CS-Fe) complexes containing 3 to 12% w/w iron. Isothermal titration calorimetry showed that the binding affinity of TPP and ATP to CS-Fe increased with the iron content of CS-Fe complexes. The stability of these nanoparticles in physiological conditions was evaluated by turbidity and by fluorescence fluctuation in real time upon dilution by electrolytes, and revealed an important stabilization effect of CS-Fe compared to CS, increasing with the iron content. Furthermore, in vitro studies on two macrophage cell lines (J774A.1 and THP-1) revealed that ATP uptake is improved consistently with the iron content of CS-Fe/ATP nanoparticles, and correlated to their lower dissociation in biological medium, allowing interesting perspectives for the intracellular delivery of ATP. PMID:25192940

  10. Antibacterial properties of composite resins incorporating silver and zinc oxide nanoparticles on Streptococcus mutans and Lactobacillus

    PubMed Central

    Kasraei, Shahin; Sami, Lida; Hendi, Sareh; AliKhani, Mohammad-Yousef; Rezaei-Soufi, Loghman

    2014-01-01

    Objectives Recurrent caries was partly ascribed to lack of antibacterial properties in composite resin. Silver and zinc nanoparticles are considered to be broad-spectrum antibacterial agents. The aim of the present study was to evaluate the antibacterial properties of composite resins containing 1% silver and zinc-oxide nanoparticles on Streptococcus mutans and Lactobacillus. Materials and Methods Ninety discoid tablets containing 0%, 1% nano-silver and 1% nano zinc-oxide particles were prepared from flowable composite resin (n = 30). The antibacterial properties of composite resin discs were evaluated by direct contact test. Diluted solutions of Streptococcus mutans (PTCC 1683) and Lactobacillus (PTCC 1643) were prepared. 0.01 mL of each bacterial species was separately placed on the discs. The discs were transferred to liquid culture media and were incubated at 37? for 8 hr. 0.01 mL of each solution was cultured on blood agar and the colonies were counted. Data was analyzed with Kruskall-Wallis and Mann-Whitney U tests. Results Composites containing nano zinc-oxide particles or silver nanoparticles exhibited higher antibacterial activity against Streptococcus mutans and Lactobacillus compared to the control group (p < 0.05). The effect of zinc-oxide on Streptococcus mutans was significantly higher than that of silver (p < 0.05). There were no significant differences in the antibacterial activity against Lactobacillus between composites containing silver nanoparticles and those containing zinc-oxide nanoparticles. Conclusions Composite resins containing silver or zinc-oxide nanoparticles exhibited antibacterial activity against Streptococcus mutans and Lactobacillus. PMID:24790923

  11. Synthesis of icariin from kaempferol through regioselective methylation and para-ClaisenCope rearrangement

    PubMed Central

    Mei, Qinggang; Wang, Chun; Zhao, Zhigang; Yuan, Weicheng

    2015-01-01

    Summary The hemisynthesis of the naturally occurring bioactive flavonoid glycoside icariin (1) has been accomplished in eleven steps with 7% overall yield from kaempferol. The 4?-OH methylation of kaempferol, the 8-prenylation of 3-O-methoxymethyl-4?-O-methyl-5-O-prenyl-7-O-benzylkaempferol (8) via para-ClaisenCope rearrangement catalyzed by Eu(fod)3 in the presence of NaHCO3, and the glycosylation of icaritin (3) are the key steps. PMID:26425179

  12. Kaempferol, a dietary flavonoid, ameliorates acute inflammatory and nociceptive symptoms in gastritis, pancreatitis, and abdominal pain.

    PubMed

    Kim, Shi Hyoung; Park, Jae Gwang; Sung, Gi-Ho; Yang, Sungjae; Yang, Woo Seok; Kim, Eunji; Kim, Jun Ho; Ha, Van Thai; Kim, Han Gyung; Yi, Young-Su; Kim, Ji Hye; Baek, Kwang-Soo; Sung, Nak Yoon; Lee, Mi-nam; Kim, Jong-Hoon; Cho, Jae Youl

    2015-07-01

    Kaempferol (KF) is the most abundant polyphenol in tea, fruits, vegetables, and beans. However, little is known about its in vivo anti-inflammatory efficacy and mechanisms of action. To study these, several acute mouse inflammatory and nociceptive models, including gastritis, pancreatitis, and abdominal pain were employed. Kaempferol was shown to attenuate the expansion of inflammatory lesions seen in ethanol (EtOH)/HCl- and aspirin-induced gastritis, LPS/caerulein (CA) triggered pancreatitis, and acetic acid-induced writhing. PMID:25917334

  13. Protective effects of kaempferol against cardiac sinus node dysfunction via CaMKII deoxidization

    PubMed Central

    An, Minae

    2015-01-01

    Kaempferol exerts cardioprotective actions through incompletely understood mechanisms. This study investigated the molecular mechanisms underlying the cardioprotective effects of kaempferol in sinus node dysfunction (SND) heart. Here, we demonstrate that angiotensin II (Ang II) infusion causes SND through oxidized calmodulin kinase II (CaMKII). In contrast to this, kaempferol protects sinus node against Ang II-induced SND. Ang II evoked apoptosis with caspase-3 activation in sinus nodal cells. However, kaempferol lowered the CaMKII oxidization and the sinus nodal cell death. To block the CaMKII oxidization, gene of p47phox, a cytosolic subunit of NADPH oxidase, was deleted using Cas9 KO plasmid. In the absence of p47phox, sinus nodal cells were highly resistance to Ang II-induced apoptosis, suggesting that oxidized-CaMKII contributed to sinus nodal cell death. In Langendorff heart from Ang II infused mice, kaempferol preserved normal impulse formation at right atrium. These data suggested that kaempferol protects sinus node via inhibition of CaMKII oxidization and may be useful for preventing SND in high risk patients. PMID:26770873

  14. CuO nanoparticles incorporated in hierarchical MFI zeolite as highly active electrocatalyst for non-enzymatic glucose sensing.

    PubMed

    Dong, Junping; Tian, Taolei; Ren, Linxiao; Zhang, Yuan; Xu, Jiaqiang; Cheng, Xiaowei

    2015-01-01

    A hierarchical MFI zeolite, with typical micro/meso bimodal pore structures, was prepared by desilication method. CuO nanoparticles (NPs) were incorporated into the hierarchical MFI zeolite by impregnation method. CuO/hierarchical zeolite composites were characterized by X-ray diffraction, transmission electron microscopy and nitrogen sorption. It is shown that the CuO nanoparticles are mostly dispersed in the mesopores with remaining of the crystallinity and morphology of the host zeolite. CuO nanoparticles located in hierarchical zeolite exhibit the excellent electrocatalytic performances to oxidation of glucose in alkaline media. The electrocatalytic activity enhances with increasing the loading content of CuO from 5% to 15%. The composites were fabricated for nonenzyme glucose sensing. Under the optimal conditions, the sensor shows a wide linear range from 510(-7) to 1.8410(-2) M with a low detection limit of 3.710(-7) M. The sensor also exhibits good repeatability, long-term stability as well as high selectivity against interfering species. PMID:25499226

  15. Silver nanoparticles and growth factors incorporated hydroxyapatite coatings on metallic implant surfaces for enhancement of osteoinductivity and antibacterial properties.

    PubMed

    Xie, Chao-Ming; Lu, Xiong; Wang, Ke-Feng; Meng, Fan-Zhi; Jiang, Ou; Zhang, Hong-Ping; Zhi, Wei; Fang, Li-Ming

    2014-06-11

    Research on incorporation of both growth factors and silver (Ag) into hydroxyapatite (HA) coatings on metallic implant surfaces for enhancing osteoinductivity and antibacterial properties is a challenging work. Generally, Ag nanoparticles are easy to agglomerate and lead to a large increase in local Ag concentration, which could potentially affect cell activity. On the other hand, growth factors immobilization requires mild processing conditions so as to maintain their activities. In this study, bone morphology protein-2 (BMP-2) and Ag nanoparticle contained HA coatings were prepared on Ti surfaces by combining electrochemical deposition (ED) of Ag and electrostatic immobilization of BMP-2. During the ED process, chitosan (CS) was selected as the stabilizing agent to chelate Ag ions and generate Ag nanoparticles that are uniformly distributed in the coatings. CS also reduces Ag toxicity while retaining its antibacterial activity. Afterwards, a BMP/heparin solution was absorbed on the CS/Ag/HA coatings. Consequently, BMP-2 was immobilized on the coatings by the electrostatic attraction between CS, heparin, and BMP-2. Sustained release of BMP-2 and Ag ions from HA coatings was successfully demonstrated for a long period. Results of antibacterial tests indicate that the CS/Ag/HA coatings have high antibacterial properties against both Staphylococcus epidermidis and Escherichia coli. Osteoblasts (OB) culture reveals that the CS/Ag/HA coatings exhibit good biocompatibility. Bone marrow stromal cells (BMSCs) culture indicates that the BMP/CS/Ag/HA coatings have good osteoinductivity and promote the differentiation of BMSCs. Ti bars with BMP/CS/Ag/HA coatings were implanted into the femur of rabbits to evaluate the osteoinductivity of the coatings. Results indicate that BMP/CS/Ag/HA coatings favor bone formation in vivo. In summary, this study presents a convenient and effective method for the incorporation of growth factors and antibacterial agents into HA coatings. This method can be utilized to modify a variety of metallic implant surfaces. PMID:24720634

  16. Tailoring acidity of HZSM-5 nanoparticles for methyl bromide dehydrobromination by Al and Mg incorporation

    PubMed Central

    2014-01-01

    Three kinds of HZSM-5 nanoparticles with different acidity were tailored by impregnating MgO or varying Si/Al ratios. Both the textural and acidic properties of the as-prepared nanoparticles were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR or Py-FTIR). It was found that the intensity of Lewis acid sites with weak strength was enhanced by impregnating MgO or reducing Al concentration, and such an enhancement could be explained by the formation of Mg(OH)+ or charge unbalance of the MgO framework on the surface of HZSM-5 support. The effect of HZSM-5 nanoparticles' acidity on methyl bromide dehydrobromination as catalyst was evaluated. As the results, MgHZ-360 catalyst with the highest concentration of Lewis acid sites showed excellent stability, which maintained methyl bromide conversion of up 97% in a period of 400 h on stream. Coke characterization by BET measurements and TGA/DTA and GC/MS analysis revealed that polymethylated naphthalenes species were formed outside the channels of the catalyst with higher acid intensity and higher Brønsted acid concentration during the initial period of reaction, while graphitic carbon formed in the channels of catalyst with lower acid intensity and higher Lewis acid concentration during the stable stage. PMID:25328502

  17. Kaempferol targets RSK2 and MSK1 to suppress ultraviolet radiation-induced skin cancer

    PubMed Central

    Langfald, Alyssa; Yang, Ge; Zhang, Yi; Yu, Dong Hoon; Kim, Myoung Ok; Lee, Mee-Hyun; Li, Haitao; Bae, Ki Beom; Kim, Hong-Gyum; Ma, Wei-Ya; Bode, Ann M.; Dong, Ziming; Dong, Zigang

    2014-01-01

    Solar ultraviolet (SUV) irradiation is a major factor in skin carcinogenesis, the most common form of cancer in the USA. The mitogen-activated protein (MAP) kinase cascades are activated by SUV irradiation. The 90 kDa ribosomal S6 kinase (RSK) and mitogen and stress activated protein kinase (MSK) proteins constitute a family of protein kinases that mediate signal transduction downstream of the MAP kinase cascades. In this study, phosphorylation of RSK and MSK1 was up-regulated in human squamous cell carcinoma (SCC) and solar UV-treated mouse skin. Kaempferol, a natural flavonol, found in tea, broccoli, grapes, apples and other plant sources, is known to have anticancer activity, but its mechanisms and direct target(s) in cancer chemoprevention are unclear. Kinase array results revealed that kaempferol inhibited RSK2 and MSK1. Pull-down assay results, ATP competition and in vitro kinase assay data revealed that kaempferol interacts with RSK2 and MSK1 at the ATP-binding pocket and inhibits their respective kinase activities. Mechanistic investigations showed that kaempferol suppresses RSK2 and MSK1 kinase activities to attenuate solar UV-induced phosphorylation of CREB and histone H3 in mouse skin cells. Kaempferol was a potent inhibitor of solar UV-induced mouse skin carcinogenesis. Further analysis showed that skin from the kaempferol-treated group exhibited a substantial reduction in solar UV-induced phosphorylation of cAMP response element-binding protein (CREB), c-Fos and histone H3. Overall, our results identify kaempferol as a safe and novel chemopreventive agent against solar UV-induced skin carcinogenesis that acts by targeting RSK2 and MSK1. PMID:24994661

  18. Kaempferol targets RSK2 and MSK1 to suppress UV radiation-induced skin cancer.

    PubMed

    Yao, Ke; Chen, Hanyong; Liu, Kangdong; Langfald, Alyssa; Yang, Ge; Zhang, Yi; Yu, Dong Hoon; Kim, Myoung Ok; Lee, Mee-Hyun; Li, Haitao; Bae, Ki Beom; Kim, Hong-Gyum; Ma, Wei-Ya; Bode, Ann M; Dong, Ziming; Dong, Zigang

    2014-09-01

    Solar UV (SUV) irradiation is a major factor in skin carcinogenesis, the most common form of cancer in the United States. The MAPK cascades are activated by SUV irradiation. The 90 kDa ribosomal S6 kinase (RSK) and mitogen and stress-activated protein kinase (MSK) proteins constitute a family of protein kinases that mediate signal transduction downstream of the MAPK cascades. In this study, phosphorylation of RSK and MSK1 was upregulated in human squamous cell carcinoma (SCC) and SUV-treated mouse skin. Kaempferol, a natural flavonol, found in tea, broccoli, grapes, apples, and other plant sources, is known to have anticancer activity, but its mechanisms and direct target(s) in cancer chemoprevention are unclear. Kinase array results revealed that kaempferol inhibited RSK2 and MSK1. Pull-down assay results, ATP competition, and in vitro kinase assay data revealed that kaempferol interacts with RSK2 and MSK1 at the ATP-binding pocket and inhibits their respective kinase activities. Mechanistic investigations showed that kaempferol suppresses RSK2 and MSK1 kinase activities to attenuate SUV-induced phosphorylation of cAMP-responsive element binding protein (CREB) and histone H3 in mouse skin cells. Kaempferol was a potent inhibitor of SUV-induced mouse skin carcinogenesis. Further analysis showed that skin from the kaempferol-treated group exhibited a substantial reduction in SUV-induced phosphorylation of CREB, c-Fos, and histone H3. Overall, our results identify kaempferol as a safe and novel chemopreventive agent against SUV-induced skin carcinogenesis that acts by targeting RSK2 and MSK1. PMID:24994661

  19. Development of new active packaging film made from a soluble soybean polysaccharide incorporating ZnO nanoparticles.

    PubMed

    Salarbashi, Davoud; Mortazavi, Seyed Ali; Noghabi, Mostafa Shahidi; Fazly Bazzaz, Bibi Sedigheh; Sedaghat, Naser; Ramezani, Mohammad; Shahabi-Ghahfarrokhi, Iman

    2016-04-20

    This study aimed to develop a soluble soybean polysaccharide (SSPS) nanocomposite incorporating ZnO nanoparticles. The nanocomposites were prepared using the solvent-casting method. SEM, AFM, DSC and X-ray diffraction methods were applied to characterize the resulting films. Furthermore, the antibacterial and anti-mold activities of SSPS/ZN films were assessed against the selected microorganisms. The results indicated that incorporating ZNs into the SSPS film affected the tensile strength and elongation at break significantly. In addition, the antibacterial, antifungal and yeasticidal activities of ZnO/SSPS films have been approved. XRD results showed a crystal plane of hexagonal ZN, while SEM showed that there was not a good affinity between ZN and SSPS. Mono-dispersed particles with clearly spherical morphology and with no voids on the surface were observed using AFM. Fluctuation in Tg and Tm resulted from incorporating ZN. In summary, the potential of ZNs as a functional filler in SSPS film has been demonstrated. PMID:26876847

  20. Improved photovoltaic performance of silicon nanowire/organic hybrid solar cells by incorporating silver nanoparticles

    PubMed Central

    2013-01-01

    Silicon nanowire (SiNW) arrays show an excellent light-trapping characteristic and high mobility for carriers. Surface plasmon resonance of silver nanoparticles (AgNPs) can be used to increase light scattering and absorption in solar cells. We fabricated a new kind of SiNW/organic hybrid solar cell by introducing AgNPs. Reflection spectra confirm the improved light scattering of AgNP-decorated SiNW arrays. A double-junction tandem structure was designed to manufacture our hybrid cells. Both short-circuit current and external quantum efficiency measurements show an enhancement in optical absorption of organic layer, especially at lower wavelengths. PMID:23418988

  1. Protective and detrimental effects of kaempferol in rat H4IIE cells: Implication of oxidative stress and apoptosis

    SciTech Connect

    Niering, Petra; Michels, Gudrun; Waetjen, Wim . E-mail: wim.waetjen@uni-duesseldorf.de; Ohler, Sandra; Steffan, Baerbel; Chovolou, Yvonni; Kampkoetter, Andreas; Proksch, Peter; Kahl, Regine

    2005-12-01

    Flavonoids are ubiquitous substances in fruits and vegetables. Among them, the flavonol kaempferol contributes up to 30% of total dietary flavonoid intake. Flavonoids are assumed to exert beneficial effects on human health, e.g., anticancer properties. For this reason, they are used in food supplements at high doses. The aim of this project was to determine the effects of kaempferol on oxidative stress and apoptosis in H4IIE rat hepatoma cells over a broad concentration range. Kaempferol is rapidly taken up and glucuronidated by H4IIE cells. The results demonstrate that kaempferol protects against H{sub 2}O{sub 2}-induced cellular damage at concentrations which lead to cell death and DNA strand breaks in the absence of H{sub 2}O{sub 2}-mediated oxidative stress. Preincubation with 50 {mu}M kaempferol exerts protection against the loss of cell viability induced by 500 {mu}M H{sub 2}O{sub 2} (2 h) while the same concentration of kaempferol reduces cell viability by 50% in the absence of H{sub 2}O{sub 2} (24 h). Preincubation with 50 {mu}M kaempferol ameliorates the strong DNA damage induced by 500 {mu}M H{sub 2}O{sub 2} while 50 {mu}M kaempferol leads to a significant increase of DNA breakage in the absence of H{sub 2}O{sub 2}. Preincubation with 50 {mu}M kaempferol reduces H{sub 2}O{sub 2}-mediated caspase-3 activity by 40% (4 h) while the same concentration of kaempferol leads to the formation of a DNA ladder in the absence of H{sub 2}O{sub 2} (24 h). It is concluded that the intake of high dose kaempferol in food supplements may not be advisable because in our cellular model protective kaempferol concentrations can also induce DNA damage and apoptosis by themselves.

  2. Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy.

    PubMed

    Zhao, Xiangwei; Xue, Jiangyang; Mu, Zhongde; Huang, Yin; Lu, Meng; Gu, Zhongze

    2015-10-15

    Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9 mg/dL. PMID:25988995

  3. Study of incorporation of silver nanoparticles onto PE-g-PAAc nonwoven fabric by ?-irradiation for water treatment

    NASA Astrophysics Data System (ADS)

    Phu, Dang Van; Quoc, Le Anh; Duy, Nguyen Ngoc; Hien, Nguyen Quoc

    2013-07-01

    Polyethylene nonwoven (PE) fabric was grafted with acrylic acid (PE-g-PAAc) by the ?-ray pre-irradiation process. The effect of dose and acrylic acid concentration on the grafting degree was investigated. The dose of about 20-30 kGy, acrylic acid concentration of 20-30%, and the reaction time of about 2 h at 90 C were selected as suitable parameters for grafting. The PE-g-PAAc fabric was then impregnated in colloidal silver nanoparticles (AgNPs) solution for incorporating AgNPs. The resultant PE-g-PAAc/AgNPs fabric containing 10,000 ppm AgNPs exhibits high antimicrobial activity (?>99%) against Escherichia coli in water. The release of silver into water filtrate determined by ICP-MS was less than 0.1 mg/L. The PE-g-PAAc/AgNPs fabric can be potentially applied for water and/or air treatment as an antimicrobial membrane filter.

  4. Nanoparticles incorporating pH-responsive surfactants as a viable approach to improve the intracellular drug delivery.

    PubMed

    Nogueira, Daniele R; Scheeren, Laís E; Pilar Vinardell, M; Mitjans, Montserrat; Rosa Infante, M; Rolim, Clarice M B

    2015-12-01

    The pH-responsive delivery systems have brought new advances in the field of functional nanodevices and might allow more accurate and controllable delivery of specific cargoes, which is expected to result in promising applications in different clinical therapies. Here we describe a family of chitosan-TPP (tripolyphosphate) nanoparticles (NPs) for intracellular drug delivery, which were designed using two pH-sensitive amino acid-based surfactants from the family N(α),N(ε)-dioctanoyl lysine as bioactive compounds. Low and medium molecular weight chitosan (LMW-CS and MMW-CS, respectively) were used for NP preparation, and it was observed that the size distribution for NPs with LMW-CS were smaller (~168 nm) than that for NPs prepared with MMW-CS (~310 nm). Hemolysis assay demonstrated the pH-dependent biomembrane disruptional capability of the constructed NPs. The nanostructures incorporating the surfactants cause negligible membrane permeabilization at pH7.4. However, at acidic pH, prevailing in endosomes, membrane-destabilizing activity in an erythrocyte lysis assay became evident. When pH decreased to 6.6 and 5.4, hemolytic capability of chitosan NPs increased along with the raise of concentration. Furthermore, studies with cell culture showed that these pH-responsive NPs displayed low cytotoxic effects against 3T3 fibroblasts. The influence of chitosan molecular weight, chitosan to TPP weight ratio, nanoparticle size and nature of the surfactant counterion on the membrane-disruptive properties of nanoparticles was discussed in detail. Altogether, the results achieved here showed that by inserting the lysine-based amphiphiles into chitosan NPs, pH-sensitive membranolytic and potentially endosomolytic nanocarriers were developed, which, therefore, demonstrated ideal feasibility for intracellular drug delivery. PMID:26354244

  5. Bacteriostatic and anti-collagenolytic dental materials through the incorporation of polyacrylic acid modified CuI nanoparticles

    DOEpatents

    Renne, Walter George; Mennito, Anthony Samuel; Schmidt, Michael Gerard; Vuthiganon, Jompobe; Chumanov, George

    2015-05-19

    Provided are antibacterial and antimicrobial surface coatings and dental materials by utilizing the antimicrobial properties of copper chalcogenide and/or copper halide (CuQ, where Q=chalcogens including oxygen, or halogens, or nothing). An antimicrobial barrier is created by incorporation of CuQ nanoparticles of an appropriate size and at a concentration necessary and sufficient to create a unique bioelectrical environment. The unique bioelectrical environment results in biocidal effectiveness through a multi-factorial mechanism comprising a combination of the intrinsic quantum flux of copper (Cu.sup.0, Cu.sup.1+, Cu.sup.2+) ions and the high surface-to-volume electron sink facilitated by the nanoparticle. The result is the constant quantum flux of copper which manifests and establishes the antimicrobial environment preventing or inhibiting the growth of bacteria. The presence of CuQ results in inhibiting or delaying bacterial destruction and endogenous enzymatic breakdown of the zone of resin inter-diffusion, the integrity of which is essential for dental restoration longevity.

  6. Fabrication of Pt nanoparticle incorporated polymer nanowires by high energy ion and electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Tsukuda, Satoshi; Takahasi, Ryouta; Seki, Shu; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Tanaka, Shun-Ichiro

    2016-01-01

    Polyvinylpyrrolidone (PVP)-Pt nanoparticles (NPs) hybrid nanowires were fabricated by high energy ion beam irradiation to PVP thin films including H2PtCl6. Single ion hitting caused crosslinking reactions of PVP and reduction of Pt ions within local cylindrical area along an ion trajectory (ion track); therefore, the PVP nanowires including Pt NPs were formed and isolated on Si substrate after wet-development procedure. The number of Pt NPs was easily controlled by the mixed ratio of PVP and H2PtCl6. However, increasing the amount of H2PtCl6 led to decreasing the radial size and separation of the hybrid nanowires during the wet-development. Additional electron beam irradiation after ion beam improved separation of the nanowires and controlled radial sizes due to an increase in the density of crosslinking points inner the nanowires.

  7. Delivery of imatinib-incorporated nanoparticles into lungs suppresses the development of monocrotaline-induced pulmonary arterial hypertension.

    PubMed

    Akagi, Satoshi; Nakamura, Kazufumi; Miura, Daiji; Saito, Yukihiro; Matsubara, Hiromi; Ogawa, Aiko; Matoba, Tetsuya; Egashira, Kensuke; Ito, Hiroshi

    2015-05-13

    Platelet-derived growth factor (PDGF) is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). Imatinib, a PDGF-receptor tyrosine kinase inhibitor, improved hemodynamics, but serious side effects and drug discontinuation are common when treating PAH. A drug delivery system using nanoparticles (NPs) enables the reduction of side effects while maintaining the effects of the drug. We examined the efficacy of imatinib-incorporated NPs (Ima-NPs) in a rat model and in human PAH-pulmonary arterial smooth muscle cells (PASMCs). Rats received a single intratracheal administration of PBS, FITC-NPs, or Ima-NPs immediately after monocrotaline injection. Three weeks after monocrotaline injection, intratracheal administration of Ima-NPs suppressed the development of pulmonary hypertension, small pulmonary artery remodeling, and right ventricular hypertrophy in the rat model of monocrotaline-induced PAH. We also examined the effects of imatinib and Ima-NPs on PDGF-induced proliferation of human PAH-PASMCs by (3)H-thymidine incorporation. Imatinib and Ima-NPs significantly inhibited proliferation after 24 hours of treatment. Ima-NPs significantly inhibited proliferation compared with imatinib at 24 hours after removal of these drugs. Delivery of Ima-NPs into lungs suppressed the development of MCT-induced PAH by sustained antiproliferative effects on PAS-MCs. PMID:25902888

  8. Enhanced Photovoltaic Performance in Polypyrrole Nanoparticles Counter Electrode Due to Incorporation of Multi-Walled Carbon Nanotubes.

    PubMed

    Baro, Mridula; Vijayan, C; Ramaprabhu, Sundara

    2015-07-01

    In this present work, Multi-walled carbon nanotubes (MWNTs) with different content by weight (10%, 20%, 30%, 50% and 70%) are introduced into Polypyrrole nanoparticles (PPy NP) matrix and fabricated as Pt free counter electrodes (CEs) for dye-sensitized solar cell (DSSC). For comparison DSSCs using pristine PPy NP, MWNTs and Platinum (Pt) were also fabricated. The incorporation of MWNTs acts as conductive channel and co-catalyst to the PPy NP CEs in the reduction of li to I-. The electrochemical catalytic activities of different CEs were analysed by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) and photovoltaic performance was studied under standard AM 1.5 sunlight illumination. It was observed that incorporation of MWNTs in the PPy NP CE greatly enhanced the catalytic activity for I3 reduction and significantly reduced the charge transfer resistance in the PPy NP/MWNTs composite CE finally improving short-circuit photocurrent density, fill factor, open circuit voltage and power conversion efficiency of DSSC. DSSC fabricated from PPy NP/MWNTs composite CE with 50% MWNTs content reached the highest photoconversion efficiency of 5.80% which is 91% that of Pt CE based DSSC (6.37%). PMID:26373060

  9. Kaempferol suppresses lipid accumulation by inhibiting early adipogenesis in 3T3-L1 cells and zebrafish.

    PubMed

    Lee, Yeon-Joo; Choi, Hyeon-Son; Seo, Min-Jung; Jeon, Hui-Jeon; Kim, Kui-Jin; Lee, Boo-Yong

    2015-08-01

    Kaempferol is a flavonoid present in Kaempferia galanga and Opuntia ficus indica var. saboten. Recent studies have suggested that it has anti-oxidant, anti-inflammatory, anti-cancer, and anti-obesity effects. In this study, we focused on the anti-adipogenic effects of kaempferol during adipocyte differentiation. The results showed that kaempferol inhibits lipid accumulation in adipocytes and zebrafish. Oil Red O and Nile Red staining showed that the number of intracellular lipid droplets decreased in adipocytes and zebrafish treated with kaempferol. LPAATθ (lysophosphatidic acid acyltransferase), lipin1, and DGAT1 (triglyceride synthetic enzymes) and FASN and SREBP-1C (fatty acid synthetic proteins) showed decreased expression levels in the presence of kaempferol. In addition, treatment of kaempferol showed an inhibitory activity on cell cycle progression. Kaempferol delayed cell cycle progression from the S to G2/M phase through the regulation of cyclins in a dose-dependent manner. Kaempferol blocked the phosphorylation of AKT (protein kinase B) and mammalian target of rapamycin (mTOR) signaling pathway during the early stages of adipogenesis. In addition, kaempferol down-regulated pro-early adipogenic factors such as CCAAT-enhancer binding proteins β (C/EBPβ), and Krüppel-like factors (KLFs) 4 and 5, while anti-early adipogenic factors, such as KLF2 and pref-1(preadipocyte factor-1), were upregulated. These kaempferol-mediated regulations of early adipogenic factors resulted in the attenuation of late adipogenic factors such as C/EBPα and peroxisome proliferator-activated receptor γ (PPARγ). These results were supported in zebrafish based on the decrease in lipid accumulation and expression of adipogenic factors. Our results indicated that kaempferol might have an anti-obesity effect by regulating lipid metabolism. PMID:26174858

  10. Hybrid organic-inorganic nanoparticles: controlled incorporation of gold nanoparticles into virus-like particles and application in surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Niebert, Marcus; Riches, James; Howes, Mark; Ferguson, Charles; Parton, Robert G.; Middelberg, Anton P. J.; Rintoul, Llew; Fredericks, Peter M.

    2007-01-01

    A capsid is the protein coat surrounding a virus' genome that ensures its protection and transport. The capsid of murine polyomavirus (muPy) consists of one major (VP1) and two minor (VP2/3) proteins, from which just VP1 is sufficient to form the capsid when expressed recombinantly (1). From a material engineering point of view, viral capsids are of interest because they present a paradigm for complex self-assembly on the nanometer scale. Understanding and controlling these assembly dynamics will allow the construction of nanoscale structures using a self-assembly process. The first step in this direction was the discovery that capsids of several viruses can be reversibly disassembled into their building blocks and reassembled using the same building blocks by simply changing the buffer conditions (2, 3). Such capsids already find applications as targeted in vivo delivery vectors for genes, proteins or small molecular drugs (4, 5), as optical probes for biomedical imaging and sensing purposes with unprecedented resolution and sensitivity and can potentially be used as templates for nanoelectronics (6, 7). Here we show the controlled incorporation of inorganic gold nanoparticles into the capsid shell of muPy. This incorporation is mediated by covalent sulfide bonds between the capsid proteins cysteine residues and the molecular gold. The number of incorporated gold particles can be controlled during the assembly process and the capsids retain their ability to transduce cells. These particles provide new tools for tracking of viral particles in cells, and simultaneously allow the delivery of genes packages in the hollow capsid.

  11. Polypropylene/glass fiber hierarchical composites incorporating inorganic fullerene-like nanoparticles for advanced technological applications.

    PubMed

    Dez-Pascual, Ana M; Naffakh, Mohammed

    2013-10-01

    Novel isotactic polypropylene (iPP)/glass fiber (GF) laminates reinforced with inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles as environmentally friendly fillers have been successfully fabricated by simple melt-blending and fiber impregnation in a hot-press without the addition of any compatibilizer. The influence of IF-WS2 concentration on the morphology, viscosity. and thermal and mechanical behavior of the hierarchical composites has been investigated. Results revealed an unprecedented 62 C increase in the degradation temperature of iPP/GF upon addition of only 4.0 wt % IF-WS2. The coexistence of both micro- and nanoscale fillers resulted in synergistic effects on enhancing the stiffness, strength, crystallinity, thermal stability, glass transition (Tg) and heat distortion temperature (HDT) of the matrix. The approach used in this work is an efficient, versatile, scalable and economic strategy to improve the mechanical and thermal behavior of GF-reinforced thermoplastics with a view to extend their use in advanced technological applications. This new type of composite materials shows great potential to improve the efficiency and sustainability of many forms of transport. PMID:24015820

  12. Bimetal (Ni-Co) nanoparticles-incorporated electrospun carbon nanofibers as an alternative counter electrode for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Rameez, Md.; Saranya, K.; Subramania, A.; Sivasankar, N.; Mallick, S.

    2016-02-01

    Counter electrode (CE) plays an important role in dye-sensitized solar cells (DSSCs). Electron transfer from external circuit to redox couple is mediated and facilitated by it to complete the DSSC circuit. Platinum (Pt) is widely employed as CE in DSSCs. However, due to its high cost and scarcity, efforts are being made to replace Pt. In this study, a bimetal (Ni-Co) nanoparticles-incorporated carbon nanofibers (CNFs) are prepared by electrospinning technique and used as CE material for DSSC applications. The morphology of prepared CNFs is characterized by field emission scanning electron microscope and transmission electron microscope studies. The structural properties are confirmed by X-ray diffraction and Raman spectroscopy studies. The electrochemical characterization of Ni-Co nanoparticles-incorporated CNFs is carried out using cyclic voltammetry, electrochemical impedance and Tafel polarization studies and compared with CNFs and std. Pt. The photo-conversion efficiency (PCE) of DSSC assembled with Ni-Co nanoparticles-incorporated CNFs as CE is very nearer to that of the same assembled with std. Pt as CE. Hence, Ni-Co nanoparticles-incorporated CNFs can be used as a cost-effective alternative CE for DSSCs.

  13. Kaempferol induced apoptosis via endoplasmic reticulum stress and mitochondria-dependent pathway in human osteosarcoma U-2 OS cells.

    PubMed

    Huang, Wen-Wen; Chiu, Yu-Jen; Fan, Ming-Jen; Lu, Hsu-Feng; Yeh, Hsiu-Feng; Li, Kun-Hong; Chen, Po-Yuan; Chung, Jing-Gung; Yang, Jai-Sing

    2010-11-01

    Kaempferol is a natural flavonoid. Previous studies have reported that kaempferol has anti-proliferation activities and induces apoptosis in many cancer cell lines. However, there are no reports on human osteosarcoma. In this study, we investigate the anti-cancer effects and molecular mechanisms of kaempferol in human osteosarcoma cells. Our results demonstrate that kaempferol significantly reduces cell viabilities of U-2 OS, HOB and 143B cells, especially U-2 OS cells in a dose-dependent manner, but exerts low cytotoxicity on human fetal osteoblast progenitor hFOB cells. Comet assay, DAPI staining and DNA gel electrophoresis confirm the effects of DNA damage and apoptosis in U-2 OS cells. Flow cytometry detects the increase of cytoplasmic Ca(2+) levels and the decrease of mitochondria membrane potential. Western blotting and fluorogenic enzymatic assay show that kaempferol treatment influences the time-dependent expression of proteins involved in the endoplasmic reticulum stress pathway and mitochondrial signaling pathway. In addition, pretreating cells with caspase inhibitors, BAPTA or calpeptin before exposure to kaempferol increases cell viabilities. The anti-cancer effects of kaempferol in vivo are evaluated in BALB/c(nu/nu) mice inoculated with U-2 OS cells, and the results indicate inhibition of tumor growth. In conclusion, kaempferol inhibits human osteosarcoma cells in vivo and in vitro. PMID:20564475

  14. Incorporation of lapatinib into human serum albumin nanoparticles with enhanced anti-tumor effects in HER2-positive breast cancer.

    PubMed

    Wan, Xu; Zheng, Xiaoyao; Pang, Xiaoying; Zhang, Zheming; Zhang, Qizhi

    2015-12-01

    Lapatinib, a selective small-molecule dual-tyrosine kinase inhibitor of HER2 and EGFR, is effective in HER2-positive patients with advanced metastatic breast cancer. However, its low and variable oral absorption, large required daily dose and serious gastrointestinal side effects all limit its clinical use. Intravenous administration offers a good option to overcome these disadvantages. However, the poor solubility of lapatinib in water and organic solvents causes lapatinib to fail in a common injectable preparation. Considering lapatinib's high albumin binding ability (>99%), in this study, we developed human serum albumin nanoparticles loaded with lapatinib (LHNPs) by Nab technology for intravenous administration and investigated its efficacy against HER2-positive breast cancer. Raman shift, X-ray diffraction and X-ray photoelectron spectroscopy studies demonstrated that lapatinib was successfully incorporated into nanoparticles, and LHNPs exhibited good stability and sustained-release effect in vitro. LHNPs could be effectively taken up by SKBr3 cells in a concentration- and time-dependent manner, and the uptake was mediated by energy-dependent endocytosis, which involved clathrin-dependent pinocytosis. Furthermore, in vitro and in vivo data indicated that LHNPs presented the strong ability to induce apoptosis and superior anti-tumor efficacy in tumor-bearing mice to the commercial tablet Tykerb through the inhibition of HER2 phosphorylation. Subchronic toxicity assays indicated that LHNPs had no hepatic or kidney toxicity. With mature technology for industrial production and enhanced therapeutic effects, LHNPs are likely to have great potential as a safe therapeutic candidate against HER2-positive breast cancer in the clinic. PMID:26539808

  15. Gold nanoparticle incorporated polymer/bioactive glass composite for controlled drug delivery application.

    PubMed

    Jayalekshmi, A C; Sharma, Chandra P

    2015-02-01

    The present study discusses the development of a biodegradable polymer encapsulated-nanogold incorporated-bioactive glass composite (AuPBG) by a low-temperature method. The composite was analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG), fluorescence and dissolution analysis. The composite exhibited aggregation behaviour in solid and solution states and exhibited negative zeta potential (-13.3 ± 1.4 mV). The composite exhibited fast degradation starting from the 5(th) day onwards in phosphate buffered saline (PBS) for a period of 14 days. The composite showed fluorescence quenching effect at pH 7 and the fluorescence recovered at pH 5. The composite has been found to be suitable for the release of doxorubicin at high rates at acidic pH (∼ 5) which is the intracellular pH of tumour cells. The drug loading ratio is also high and it exhibited a controlled release for a period of 8 days in PBS. The system serves as a promising material for targeted drug delivery applications. PMID:25576810

  16. Pollination- or Wound-Induced Kaempferol Accumulation in Petunia Stigmas Enhances Seed Production.

    PubMed Central

    Vogt, T.; Pollak, P.; Tarlyn, N.; Taylor, L. P.

    1994-01-01

    Flavonols are essential for pollen germination and tube growth in petunia and can be supplied by either the pollen or stigma at pollination. HPLC analysis and a sensitive bioassay demonstrated that both pollination and wounding induce flavonol accumulation, especially kaempferol, in the outer cell layers and exudate of the stigma. Pollination and wounding induced nearly identical flavonol kinetics and patterns of accumulation in the same target tissue, suggesting that they share elements of a common signal transduction pathway. The wound response was systemic, because kaempferol accumulated in the stigma when distal tissues, such as the corolla, stamens, or sepals, were wounded. We have exploited the germination requirement for flavonols and the high level of kaempferol that accumulates after wounding to enhance plant fecundity. Seed set was significantly increased by mechanically wounding the corolla and stamens prior to the application of pollen to the stigma. A reproductive role for a plant secondary metabolite and the specific function of stigmatic kaempferol are discussed from an evolutionary perspective. PMID:12244218

  17. Spectrophotometric determination of antimony with 3,5,7,4'-tetrahydroxyflavone (kaempferol).

    PubMed

    Garg, B S; Trikha, K C; Singh, R P

    1969-03-01

    A selective spectrophotometric method is described for determination of antimony with kaempferol. Microgram amounts of antimony can be determined by measurements at 420 run in 0.1M hydrochloric acid. The molar absorptivity is 1.09 x 10(4) at 420 nm and the optimum range for accurate determination is 1.9-7.8 ppm of antimony. PMID:18960527

  18. Nanoparticles of gadolinium-incorporated Prussian blue with PEG coating as an effective oral MRI contrast agent for gastrointestinal tract imaging.

    PubMed

    Perera, Vindya S; Chen, Guojun; Cai, Qing; Huang, Songping D

    2016-03-01

    Biocompatible nanoparticles of gadolinium-incorporated Prussian blue with the empirical formula K0.94Gd0.02Fe[Fe(CN)6] exhibit extremely high stability against the release of Gd(3+) and CN(-) ions under the acidic conditions similar to stomach juice. The high r1 relaxivity, low cytotoxicity and the ability of such nanoparticles to penetrate the cell membrane suggest that this coordination-polymer structural platform offers a unique opportunity for developing the next generation of T1-weighted oral cellular MRI probes for the early detection of tumors in the gastrointestinal tract. PMID:26890149

  19. Non-covalent functionalization of graphene oxide by polyindole and subsequent incorporation of Ag nanoparticles for electrochemical applications

    NASA Astrophysics Data System (ADS)

    Dubey, Prashant; Kumar, Ashish; Prakash, Rajiv

    2015-11-01

    Reduced graphene oxide (r-GO) sheets have been modified by polyindole (PIn) via in situ chemical oxidation method to obtain stable dispersion in water and furthermore incorporation of Ag nanoparticles (Ag NPs); the resulting Ag NPs/PIn-r-GO nanocomposite is demonstrated for electrochemical applications. Ag NPs/r-GO and PIn/GO nanocomposites have also been prepared for its comparative study with Ag NPs/PIn-r-GO. Non-covalent functionalization of GO by PIn polymer leads to PIn-GO dispersion, which is stable for several months without any precipitation. This dispersed solution is used for formation of Ag NPs/PIn-r-GO nanocomposite. Various experimental tools like UV-vis, FTIR and TEM have been used to characterize as-synthesized materials. Thereafter electrochemical performance of as-synthesized nanocomposites have been compared for their charge capacitive behaviour (without its poisoning compared to Ag NPs/r-GO) which leads to be an excellent candidate for the possible applications such as electrocatalysis, charge storage devices, etc. We observed that Ag NPs/PIn-r-GO nanocomposite exhibits better processability and electroactivity as electrode material in comparison to Ag NPs/r-GO and PIn/GO nanocomposites due to synergistic effect of individual components.

  20. One-step synthesis of size-tunable Ag nanoparticles incorporated in electrospun PVA/cyclodextrin nanofibers.

    PubMed

    Celebioglu, Asli; Aytac, Zeynep; Umu, Ozgun C O; Dana, Aykutlu; Tekinay, Turgay; Uyar, Tamer

    2014-01-01

    One-step synthesis of size-tunable silver nanoparticles (Ag-NP) incorporated into electrospun nanofibers was achieved. Initially, in situ reduction of silver salt (AgNO3) to Ag-NP was carried out in aqueous solution of polyvinyl alcohol (PVA). Here, PVA was used as reducing agent and stabilizing polymer as well as electrospinning polymeric matrix for the fabrication of PVA/Ag-NP nanofibers. Afterwards, hydroxypropyl-beta-cyclodextrin (HP?CD) was used as an additional reducing and stabilizing agent in order to control size and uniform dispersion of Ag-NP. The size of Ag-NP was ?8 nm and some Ag-NP aggregates were observed for PVA/Ag-NP nanofibers, conversely, the size of Ag-NP decreased from ?8 nm down to ?2 nm within the fiber matrix without aggregation were attained for PVA/HP?CD nanofibers. The PVA/Ag-NP and PVA/HP?CD/Ag-NP nanofibers exhibited surface enhanced Raman scattering (SERS) effect. Moreover, antibacterial properties of PVA/Ag-NP and PVA/HP?CD/Ag-NP nanofibrous mats were tested against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. PMID:24274573

  1. Influence of Incorporated Pt-Fe2O3 Core-Shell Nanoparticles on the Resistive Switching Characteristics of ZnO Thin Film.

    PubMed

    Yoo, E J; Kang, S Y; Shim, E L; Yoon, T S; Kang, C J; Choi, Y J

    2015-11-01

    The resistance-switching characteristics of metal oxides have attracted great interest for the non-volatile memory applications such as resistive random access memory. A basic resistive random access memory device has a metal/insulator/metal structure, and its memory effect is achieved by applying voltage to change the resistance of the insulating layer. One of the promising candidates for explaining the resistance-switching mechanism is the formation and rupture of nanoscale conductive filaments. However, this model has an issue that needs to be addressed: the wide distribution of switching voltage due to randomly formed filaments. Therefore, some researchers have reported a decrease in switching voltage distribution and an increase in switching stability by incorporating nanoparticles into the insulating layer. In this study, we investigated influence of incorporated Pt-Fe2O3 core-shell nanoparticles on the resistive switching characteristics of ZnO thin films. Devices were fabricated on SiO2 wafers. A 100-nm-thick Cr layer was used as the bottom electrode. A 50-nm-thick ZnO layer was deposited using the sputtering method, and Pt-Fe2O3 nanoparticles were deposited on it by the dip coating method. A 50-nm-thick ZnO layer was then deposited again. A top Cr electrode (size: 100 ?m x 100 ?m) was deposited using a shadow mask and sputtering system. All the devices showed bipolar resistance-switching behavior that is observed in Cr/ZnO/Cr structures. However, the on/off voltage was dramatically lowered by incorporating nanoparticles into the insulating layer when compared with that of the devices without nanoparticles. In addition, the switching stability of the devices was improved upon the incorporation of nanoparticles. On the basis of these results, we can conclude that Pt-Fe2O3 nanoparticles may be used to enhance the resistance switching properties of ZnO thin films by incorporating them into the films. PMID:26726563

  2. Kaempferol-3-O-rutinoside from Afgekia mahidoliae promotes keratinocyte migration through FAK and Rac1 activation.

    PubMed

    Petpiroon, Nareerat; Suktap, Chalermlat; Pongsamart, Sunanta; Chanvorachote, Pithi; Sukrong, Suchada

    2015-07-01

    The restoration of the epidermal epithelium through re-epithelialization is a critical process in wound healing. Directed keratinocyte migration to the wound is required, and the retardation of this process may result in a chronic, non-healing wound. The present study contributes to research aiming to identify promising compounds that promote wound healing using a human keratinocyte model. The effects of three kaempferol glycosides from an Afgekia mahidoliae leaf extract, kaempferol-3-O-arabinoside, kaempferol-3-O-glucoside, and kaempferol-3-O-rutinoside, on keratinocyte migration were determined. Interestingly, kaempferol-3-O-rutinoside exhibited a pronounced effect on wound closure in comparison to the parental kaempferol and other glycosides. The mechanism by which kaempferol-3-O-rutinoside enhances cell migration involves the induction of filopodia and lamellipodia formation, increased cellular levels of phosphorylated FAK (Tyr 397) and phosphorylated Akt (Ser 473), and up-regulation of active Rac1-GTP. The data obtained in this study may support the development of this compound for use in wound healing therapies. PMID:25783411

  3. Regulation of heme oxygenase-1 expression and MAPK pathways in response to kaempferol and rhamnocitrin in PC12 cells

    SciTech Connect

    Hong, J.-T.; Yen, J.-H.; Wang Lisu; Lo, Y.-H.; Chen, Z.-T.; Wu, M.-J.

    2009-05-15

    Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities, especially neural diseases. Our aim of research is to investigate the protective effects and mechanisms of kaempferol and rhamnocitrin (kaempferol-7-methyl ether) on oxidative damage in rat pheochromocytoma PC12 cells induced by a limited supply of serum and hydrogen peroxide (H{sub 2}O{sub 2}). The current result demonstrated that kaempferol protected PC12 cells from serum deprivation-induced apoptosis. Pretreatment of cells with kaempferol also diminished intracellular generation of reactive oxygen species (ROS) in response to H{sub 2}O{sub 2} and strongly elevated cell viability. RT-Q-PCR and Western blotting revealed that kaempferol and rhamnocitrin significantly induced heme oxygenase (HO)-1 gene expression. Addition of zinc protoporphyrin (Znpp), a HO-1 competitive inhibitor, significantly attenuated their protective effects in H{sub 2}O{sub 2}-treated cells, indicating the vital role of HO-1 in cell resistance to oxidative injury. While investigating the signaling pathways responsible for HO-1 induction, we observed that kaempferol induced sustained extracellular signal-regulated protein kinase 1/2 (ERK1/2) in PC12 cells grown in low serum medium; while rhamnocitrin only stimulated transient ERK cascade. Addition of U0126, a highly selective inhibitor of MEK1/2, which is upstream of ERK1/2, had no effect on kaempferol- or rhamnocitrin-induced HO-1 mRNA expression, indicating no direct cross-talk between these two pathways. Furthermore, both kaempferol and rhamnocitrin were able to persistently attenuate p38 phosphorylation. Taking together, the above findings suggest that kaempferol and rhamnocitrin can augment cellular antioxidant defense capacity, at least in part, through regulation of HO-1 expression and MAPK signal transduction.

  4. Kaempferol enhances cisplatin's effect on ovarian cancer cells through promoting apoptosis caused by down regulation of cMyc

    PubMed Central

    2010-01-01

    Background Ovarian cancer is one of the most significant malignancies in the western world. Studies showed that Ovarian cancers tend to grow resistance to cisplatin treatment. Therefore, new approaches are needed in ovarian cancer treatment. Kaempferol is a dietary flavonoid that is widely distributed in fruits and vegetables, and epidemiology studies have revealed a protective effect of kaempferol against ovarian cancer risk. Our early studies also found that kaempferol is effective in reducing vascular endothelial growth factor (VEGF) expression in ovarian cancer cells. In this study, we investigated kaempferol's effects on sensitizing ovarian cancer cell growth in response to cisplatin treatment. Results Ten chemicals were screened for sensitizing OVCAR-3 ovarian cancer cell growth in response to cisplatin treatment. For kaempferol, which shows a significant synergistic interaction with cisplatin, expression of ABCC1, ABCC5, ABCC6, NFkB1, cMyc, and CDKN1A genes was further examined. For cisplatin/kaempferol treatments on OVCAR-3 cancer cells, the mRNA levels of ABCC1, ABCC5, and NFkB1 did not change. However, significant inhibition of ABCC6 and cMyc mRNA levels was observed for the cisplatin/kaempferol combined treatment. The CDKN1A mRNA levels were significantly up-regulated by cisplatin/kaempferol treatment. A plot of CDKN1A mRNA levels against that of cMyc gene further revealed a reverse, linear relationship, proving cMyc's regulation on CDKN1A gene expressions. Our work found that kaempferol works synergistically with cisplatin in inhibiting ovarian cancer cell viability, and their inhibition on cell viabilities was induced through inhibiting ABCC6 and cMyc gene transcription. Apoptosis assay showed the addition of 20 ?M kaempferol to the cisplatin treatment induces the apoptosis of the cancer cells. Conclusions Kaempferol enhances the effect of cisplatin through down regulation of cMyc in promoting apoptosis of ovarian cancer cells. As a dietary component, kaempferol sensitizes ovarian cancer cells to cisplatin treatment and deserves further studies for possible applications in chemotherapy of ovarian cancers. PMID:20459793

  5. CdS nanoparticles incorporated onion-like mesoporous silica films: Ageing-induced large stokes shifted intense PL emission

    NASA Astrophysics Data System (ADS)

    Mishra, Manish Kr; Mandal, Abhijit; Saha, Jony; De, Goutam

    2013-10-01

    CdS nanoparticles (NPs) were generated in onion-like ordered mesoporous SiO2 films through a modified sol-gel process using P123 as a structure directing agent. Initially Cd2+ doped (12 equivalent mol% with respect to the SiO2) mesoporous SiO2 films were prepared on glass substrate. These films after heat-treatment at 350 C in air yielded transparent mesoporous SiO2 films having hexagonally ordered onion-like pore channels embedded with uniformly dispersed CdO NPs. The generated CdO NPs were transformed into CdS NPs after exposing the films in H2S gas at 200 C for 2 h. The as-prepared CdS NPs incorporated mesoporous SiO2 films (transparent and bright yellow in color) showed a band-edge emission at 485 nm and a weak surface defect related emission at 530 nm. During ageing of the films in ambient condition the band-edge emission gradually weakened with time and almost disappeared after about 15 days with concomitant increase of defect related strong surface state emission band near 615 nm. This transformation was related to the decay of initially formed well crystalline CdS to relatively smaller and weakly crystalline CdS NPs with surface defects due to gradual oxidation of surface sulfide. At this condition the embedded CdS NPs show large Stokes shifted (180 nm) intense broad emission which could be useful for luminescent solar concentrators. The detailed process was monitored by UV-Visible, FTIR and Raman spectroscopy, XPS, XRD and TEM studies. The evolution of photoluminescence (PL) and life times of CdS/SiO2 films were monitored with respect to the ageing time.

  6. ZnO nanoparticle incorporated nanostructured metallic titanium for increased mesenchymal stem cell response and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Elizabeth, Elmy; Baranwal, Gaurav; Krishnan, Amit G.; Menon, Deepthy; Nair, Manitha

    2014-03-01

    Recent trends in titanium implants are towards the development of nanoscale topographies that mimic the nanoscale properties of bone tissue. Although the nanosurface promotes the integration of osteoblast cells, infection related problems can also occur, leading to implant failure. Therefore it is imperative to reduce bacterial adhesion on an implant surface, either with or without the use of drugs/antibacterial agents. Herein, we have investigated two different aspects of Ti surfaces in inhibiting bacterial adhesion and concurrently promoting mammalian cell adhesion. These include (i) the type of nanoscale topography (Titania nanotube (TNT) and Titania nanoleaf (TNL)) and (ii) the presence of an antibacterial agent like zinc oxide nanoparticles (ZnOnp) on Ti nanosurfaces. To address this, periodically arranged TNT (80-120 nm) and non-periodically arranged TNL surfaces were generated by the anodization and hydrothermal techniques respectively, and incorporated with ZnOnp of different concentrations (375 μM, 750 μM, 1.125 mM and 1.5 mM). Interestingly, TNL surfaces decreased the adherence of staphylococcus aureus while increasing the adhesion and viability of human osteosarcoma MG63 cell line and human mesenchymal stem cells, even in the absence of ZnOnp. In contrast, TNT surfaces exhibited an increased bacterial and mammalian cell adhesion. The influence of ZnOnp on these surfaces in altering the bacterial and cell adhesion was found to be concentration dependent, with an optimal range of 375-750 μM. Above 750 μM, although bacterial adhesion was reduced, cellular viability was considerably affected. Thus our study helps us to infer that nanoscale topography by itself or its combination with an optimal concentration of antibacterial ZnOnp would provide a differential cell behavior and thereby a desirable biological response, facilitating the long term success of an implant.

  7. Cu-Au-Ag alloy nanoparticles incorporated silica films using a new three-layer deposition technique.

    PubMed

    Pal, Sudipto; Bysakh, Sandip; De, Goutam

    2010-02-01

    Formation of Au-Ag-Cu ternary alloy nanoparticles (NPs) is difficult mainly because the system Cu/Ag is immiscible. We present a new synthetic technique to generate such ternary alloy NPs in silica film matrix employing a three-layer (3L) coating design. In this methodology three successive coating layers were deposited on silica glass substrates from separately prepared Cu-, Au- and Ag-ion incorporated inorganic-organic hybrid silica sols by dipping method. The Au layer is kept in the middle because it is miscible with both the Ag and Cu. The 3L film assembly was subjected to UV- and heat-treatment at 450-750 degrees C in H2-N2 atmosphere. UV-treatment generates small Au and Ag NPs in the respective layers and Cu remains as Cu2+; subsequent heat-treatment in H2-N2 induces the formation of ternary alloy NPs by the interlayer diffusion of nanometals. The final heat-treated film (750 degrees C/H2-N2) shows single and sharp plasmon band centered at 480 nm in the UV-visible spectrum indicating the formation of alloy (solid solution) NPs. GIXRD study shows one set of diffraction peaks which are shifted towards higher angle with respect to the Au or Ag diffraction peaks. FESEM, GIXRD, HRTEM, and SAED analyses reveal that the alloy has a composition close to (Au + Ag)0.88Cu0.12. The EDS analyses using the nano probe attached with TEM confirm the presence of Au, Ag and Cu in all the alloy NPs. PMID:20352717

  8. Petals of Crocus sativus L. as a potential source of the antioxidants crocin and kaempferol.

    PubMed

    Zeka, Keti; Ruparelia, Ketan C; Continenza, Maria A; Stagos, Dimitrios; Vegli, Francesco; Arroo, Randolph R J

    2015-12-01

    Saffron from the province of L'Aquila, in the Abruzzo region of Italy, is highly prized and has been awarded a formal recognition by the European Union with EU Protected Designation of Origin (PDO) status. Despite this, the saffron regions are abandoned by the younger generations because the traditional cultivation of saffron (Crocus sativus L.) is labour intensive and yields only one crop of valuable saffron stamens per year. Petals of the saffron Crocus have had additional uses in traditional medicine and may add value to the crops for local farmers. This is especially important because the plant only flowers between October and November, and farmers will need to make the best use of the flowers harvested in this period. Recently, the petals of C. sativus L., which are considered a waste material in the production of saffron spice, were identified as a potential source of natural antioxidants. The antioxidants crocin and kaempferol were purified by flash column chromatography, and identified by thin layer chromatography (TLC), HPLC-DAD, infrared (IR), and nuclear magnetic resonance ((1)H &(13)C NMR) spectroscopy. The antioxidant activity was determined with the ABTS and DPPH tests. The antioxidant activities are mainly attributed to carotenoid and flavonoid compounds, notably glycosides of crocin and kaempferol. We found in dried petals 0.6% (w/w) and 12.6 (w/w) of crocin and kaempferol, respectively. Petals of C. sativus L. have commercial potential as a source for kaempferol and crocetin glycosides, natural compounds with antioxidant activity that are considered to be the active ingredients in saffron-based herbal medicine. PMID:26012879

  9. Induction of caspase cascade pathway by kaempferol-3-O-rhamnoside in LNCaP prostate cancer cell lines

    PubMed Central

    HALIMAH, ELI; DIANTINI, AJENG; DESTIANI, DIKA P.; PRADIPTA, IVAN S.; SASTRAMIHARDJA, HERRI S.; LESTARI, KERI; SUBARNAS, ANAS; ABDULAH, RIZKY; KOYAMA, HIROSHI

    2015-01-01

    Prostate cancer has become a leading cause of mortality in humans. Previous studies have shown the potential anticancer properties of kaempferol-3-O-rhamnoside in breast cancer cell lines. In the present study, the anticancer potential of kaempferol-3-O-rhamnoside was investigated in LNCaP human prostate cancer cell lines. The inhibition of cell proliferation was investigated using MTT assays, whereas its ability to induce the caspase-cascade pathway was investigated by western blotting. The results showed that kaempferol-3-O-rhamnoside inhibits the proliferation of LNCaP cells in a dose-dependent manner by upregulating the expression of caspase-8, caspase-9, caspase-3 and poly (ADP-ribose) polymerase proteins. Although further studies are required, the results of the present study indicate the potential application of kaempferol-3-O-rhamnoside in cancer treatment. PMID:25469259

  10. Kaempferol-human serum albumin interaction: Characterization of the induced chirality upon binding by experimental circular dichroism and TDDFT calculations

    NASA Astrophysics Data System (ADS)

    Matei, Iulia; Ionescu, Sorana; Hillebrand, Mihaela

    2012-10-01

    The experimental induced circular dichroism (ICD) and absorption spectra of the achiral flavonoid kaempferol upon binding to human serum albumin (HSA) were correlated to electronic CD and UV-vis spectra theoretically predicted by time-dependent density functional theory (TDDFT). The neutral and four anionic species of kaempferol in various conformations were considered in the calculations. The appearance of the experimental ICD signal was rationalized in terms of kaempferol binding to HSA in a distorted, chiral, rigid conformation. The comparison between the experimental and simulated spectra allowed for the identification of the kaempferol species that binds to HSA, namely the anion generated by deprotonation of the hydroxyl group in position 7. This approach constitutes a convenient method for evidencing the binding species and for determining its conformation in the binding pocket of the protein. Its main advantage over the UV-vis absorption method lays in the fact that only the bound ligand species gives an ICD signal.

  11. Kaempferol Inhibits Endoplasmic Reticulum Stress-Associated Mucus Hypersecretion in Airway Epithelial Cells And Ovalbumin-Sensitized Mice

    PubMed Central

    Choi, Yean-Jung; Kang, Min-Kyung; Kim, Yun-Ho; Kang, Young-Hee

    2015-01-01

    Mucus hypersecretion is an important pathological feature of chronic airway diseases, such as asthma and pulmonary diseases. MUC5AC is a major component of the mucus matrix forming family of mucins in the airways. The initiation of endoplasmic reticulum (ER)-mediated stress responses contributes to the pathogenesis of airway diseases. The present study investigated that ER stress was responsible for airway mucus production and this effect was blocked by the flavonoid kaempferol. Oral administration of ≥10 mg/kg kaempferol suppressed mucus secretion and goblet cell hyperplasia observed in the bronchial airway and lung of BALB/c mice sensitized with ovalbumin (OVA). TGF-β and tunicamycin promoted MUC5AC induction after 72 h in human bronchial airway epithelial BEAS-2B cells, which was dampened by 20 μM kaempferol. Kaempferol inhibited tunicamycin-induced ER stress of airway epithelial cells through disturbing the activation of the ER transmembrane sensor ATF6 and IRE1α. Additionally, this compound demoted the induction of ER chaperones such as GRP78 and HSP70 and the splicing of XBP-1 mRNA by tunicamycin. The in vivo study further revealed that kaempferol attenuated the induction of XBP-1 and IRE1α in epithelial tissues of OVA-challenged mice. TGF-β and tunicamycin induced TRAF2 with JNK activation and such induction was deterred by kaempferol. The inhibition of JNK activation encumbered the XBP-1 mRNA splicing and MUC5AC induction by tunicamycin and TGF-β. These results demonstrate that kaempferol alleviated asthmatic mucus hypersecretion through blocking bronchial epithelial ER stress via the inhibition of IRE1α-TRAF2-JNK activation. Therefore, kaempferol may be a potential therapeutic agent targeting mucus hypersecretion-associated pulmonary diseases. PMID:26599511

  12. The dietary flavonoid kaempferol effectively inhibits HIF-1 activity and hepatoma cancer cell viability under hypoxic conditions

    SciTech Connect

    Mylonis, Ilias; Lakka, Achillia; Tsakalof, Andreas; Institute of Biomedical Research and Technology , 51 Papanastasiou str., 41222 Larissa ; Simos, George; Institute of Biomedical Research and Technology , 51 Papanastasiou str., 41222 Larissa

    2010-07-16

    Research highlights: {yields} Kaempferol inhibits HIF-1 activity in hepatocarcinoma cells; {yields} Kaempferol causes cytoplasmic mislocalization of HIF-1{alpha} by impairing the MAPK pathway. {yields} Viability of hepatocarcinoma cells under hypoxia is reduced by kaempferol. -- Abstract: Hepatocellular carcinoma (HCC) is characterized by high mortality rates and resistance to conventional treatment. HCC tumors usually develop local hypoxia, which stimulates proliferation of cancer cells and renders them resilient to chemotherapy. Adaptation of tumor cells to the hypoxic conditions depends on the hypoxia-inducible factor 1 (HIF-1). Over-expression of its regulated HIF-1{alpha} subunit, an important target of anti-cancer therapy, is observed in many cancers including HCC and is associated with severity of tumor growth and poor patient prognosis. In this report we investigate the effect of the dietary flavonoid kaempferol on activity, expression levels and localization of HIF-1{alpha} as well as viability of human hepatoma (Huh7) cancer cells. Treatment of Huh7 cells with kaempferol under hypoxic conditions (1% oxygen) effectively inhibited HIF-1 activity in a dose-dependent manner (IC{sub 50} = 5.16 {mu}M). The mechanism of this inhibition did not involve suppression of HIF-1{alpha} protein levels but rather its mislocalization into the cytoplasm due to inactivation of p44/42 MAPK by kaempferol (IC{sub 50} = 4.75 {mu}M). Exposure of Huh7 cells to 10 {mu}{Mu} kaempferol caused significant reduction of their viability, which was remarkably more evident under hypoxic conditions. In conclusion, kaempferol, a non-toxic natural food component, inhibits both MAPK and HIF-1 activity at physiologically relevant concentrations (5-10 {mu}M) and suppresses hepatocarcinoma cell survival more efficiently under hypoxia. It has, therefore, potential as a therapeutic or chemopreventive anti-HCC agent.

  13. Improved performance of poly(3,4-ethylenedioxythiophene):poly(stylene sulfonate)/n-Si hybrid solar cell by incorporating silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Khatri, Ishwor; Liu, Qiming; Ueno, Keiji; Shirai, Hajime

    2014-11-01

    We report an enhancement in the efficiency of poly(3,4-ethylenedioxythiophene):poly(stylene sulfonate) (PEDOT:PSS)/n-Si hybrid solar cell by incorporating silver nanoparticles (AgNPs) with PEDOT:PSS. AgNPs were prepared by reducing silver nitrate in green-tea solution, which showed characteristic absorption peak due to the surface plasmonic resonance effect. AgNPs incorporated PEDOT:PSS/n-Si hybrid device shows power conversion efficiency (?) of 10.21%, which is comparatively higher to the performance of pristine device without AgNPs. Here, we noticed that incorporation of AgNPs decreases sheet resistance and enlarged surface roughness of PEDOT:PSS film for the efficient collection of charges, rather than plasmonic effect.

  14. Dietary Flavonoids as Therapeutics for Preterm Birth: Luteolin and Kaempferol Suppress Inflammation in Human Gestational Tissues In Vitro

    PubMed Central

    Wall, Courtney; Lim, Ratana; Poljak, Marin; Lappas, Martha

    2013-01-01

    Infection/inflammation is commonly associated with preterm birth (PTB), initiating uterine contractions and rupture of fetal membranes. Proinflammatory cytokines induce matrix metalloproteinases (MMPs) that degrade the extracellular matrix (ECM) and prostaglandins which initiate uterine contractions. Nuclear factor-?B (NF-?B) and activator-protein- (AP-)1 have key roles in the formation of these prolabour mediators. In nongestational tissues, dietary flavonoids such as luteolin and kaempferol inhibit NF-?B, AP-1, and their downstream targets. The aim of this study was to determine if luteolin and kaempferol reduce infection-induced prolabour mediators in human gestational tissues. Fetal membranes were incubated with LPS, and primary amnion cells and myometrial cells were incubated with IL-1? in the absence or presence of luteolin or kaempferol. Luteolin and kaempferol significantly reduced LPS-induced secretion of proinflammatory cytokines (IL-6 and IL-8) and prostaglandins (PGE2 and PGF2?) in fetal membranes, IL-1?-induced COX-2 gene expression and prostaglandin production in myometrium, and IL-1?-induced MMP-9 activity in amnion and myometrial cells. Luteolin and kaempferol decreased IL-1?-induced NF-?B p65 DNA binding activity and nuclear c-Jun expression. In conclusion, luteolin and kaempferol inhibit prolabour mediators in human gestational tissues. Given the central role of inflammation in provoking preterm labour, phytophenols may be a therapeutic approach to reduce the incidence of PTB. PMID:23840918

  15. Kaempferol inhibits VEGF expression and in vitro angiogenesis through a novel ERK-NFκB-cMyc-p21 pathway

    PubMed Central

    Luo, Haitao; Rankin, Gary O.; Juliano, Noelle; Jiang, Bing-Hua; Chen, Yi Charlie

    2011-01-01

    Kaempferol has been reported to reduce the risk of ovarian cancer, but the mechanism is not completely understood. In this study, we tend to expand our understanding on how kaempferol regulates VEGF expression and angiogenesis in ovarian cancer cells. We timed VEGF secretion, and studied in-vitro angiogenesis by kaempferol treatment. Gene expression was examined by qRT-PCR, ELISA, Western Blotting, or luciferase assay, and pathways were examined by manipulating genetic components with plasmid or siRNA transfection. It was found that kaempferol time-dependently inhibited VEGF secretion, and suppressed in-vitro angiogenesis. Kaempferol down-regulated ERK phosphorelation as well as NFκB and cMyc expression, but promoted p21 expression. Examination of relationship between these genes suggested a novel ERK-NFκB-cMyc-p21-VEGF pathway, which accounts for kaempferol’s angioprevention effects in ovarian cancer cells. This data supplements our comprehension of the mechanisms behind kaempferol’s biological influence in ovarian cancer cells, and better characterized kaempferol toward chemoprevention. PMID:21927533

  16. Antimicrobial and antioxidant activity of kaempferol rhamnoside derivatives from Bryophyllum pinnatum

    PubMed Central

    2012-01-01

    Background Bryophyllum pinnatum (Lank.) Oken (Crassulaceae) is a perennial succulent herb widely used in traditional medicine to treat many ailments. Its wide range of uses in folk medicine justifies its being called "life plant" or "resurrection plant", prompting researchers' interest. We describe here the isolation and structure elucidation of antimicrobial and/or antioxidant components from the EtOAc extract of B. pinnatum. Results The methanol extract displayed both antimicrobial activities with minimum inhibitory concentration (MIC) values ranging from 32 to 512 ?g/ml and antioxidant property with an IC50 value of 52.48 ?g/ml. Its partition enhanced the antimicrobial activity in EtOAc extract (MIC = 16-128 ?g/ml) and reduced it in hexane extract (MIC = 256-1024 ?g/ml). In addition, this process reduced the antioxidant activity in EtOAc and hexane extracts with IC50 values of 78.11 and 90.04 ?g/ml respectively. Fractionation of EtOAc extract gave seven kaempferol rhamnosides, including; kaempferitrin (1), kaempferol 3-O-?-L-(2-acetyl)rhamnopyranoside-7-O-?-L-rhamnopyranoside (2), kaempferol 3-O-?-L-(3-acetyl)rhamnopyranoside-7-O-?-L-rhamnopyranoside (3), kaempferol 3-O-?-L-(4-acetyl)rhamnopyranoside-7-O-?-L-rhamnopyranoside (4), kaempferol 3-O-?-D- glucopyranoside-7-O-?-L-rhamnopyranoside (5), afzelin (6) and ?-rhamnoisorobin (7). All these compounds, except 6 were isolated from this plant for the first time. Compound 7 was the most active, with MIC values ranging from 1 to 2 ?g/ml and its antioxidant activity (IC50 = 0.71 ?g/ml) was higher than that of the reference drug (IC50 = 0.96 ?g/ml). Conclusion These findings demonstrate that Bryophyllum pinnatum and some of its isolated compounds have interesting antimicrobial and antioxidant properties, and therefore confirming the traditional use of B. pinnatum in the treatment of infectious and free radical damages. PMID:22433844

  17. Effect of crystallographic phase on green and yellow emissions in Mn-doped zinc silicate nanoparticles incorporated in silica host matrix

    NASA Astrophysics Data System (ADS)

    El Mir, L.; Omri, K.; El Ghoul, J.

    2015-09-01

    Silica host matrix reached by manganese-doped zinc silicate nanoparticles (SiO2/Zn2SiO4:Mn) were in-situ synthesized by a sol-gel process. In our approach, we synthesis ZnO:Mn nanoparticles in supercritical conditions of ethanol. After the incorporation of these nanoparticles in silica host matrix, a heat treatment at 1200 C and 1500 C for 2 h was performed for the elaboration of SiO2/Zn2SiO4:Mn nanocomposites. Then, these samples were characterized by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and photoluminescence (PL). These samples exhibit broad green and yellow PL bands depending on synthesis temperature. The SiO2/Zn2SiO4:Mn prepared at 1200 C exhibit a green emission centered at about 525 nm while the yellow emission centered at 575 nm resulted from SiO2/Zn2SiO4:Mn prepared at 1500 C. These two emissions are originated from internal transition in Mn2+ ion doped zinc silicate nanoparticles and the emission wavelength is correlated to the local crystalline field which is fixed by the crystallographic phase.

  18. Catalyzed radical polymerization of styrene vapor on nanoparticle surfaces and the incorporation of metal and metal oxide nanoparticles within polystyrene polymers.

    PubMed

    Abdelsayed, Victor; Alsharaeh, Edreese; El-Shall, M Samy

    2006-10-01

    We present a novel approach to polymerize olefin vapors on the surfaces of metallic and semiconductor nanoparticles. In this approach, a free radical initiator such as AIBN is dissolved in a volatile solvent such as acetone. Selected nanoparticles (prepared separately using the laser vaporization-controlled condensation method) are used to form initiator-coated nanoparticles placed on a glass substrate. The olefin (styrene) vapor is polymerized by the thermally activated initiator on the nanoparticle surfaces. Our approach also provides structural and mechanistic information on the early stages of catalyzed gas-phase polymerization, which can be used to correlate the gas-phase structural properties with the bulk properties and the performance of the polymer nanocomposites. This correlation is the key step in controlling the properties of the polymer nanocomposites. Our results clearly demonstrate the success of this method in preparing polymer coated nanoparticles for a variety of interesting applications. The precise control of the chemical functionality, thickness, and morphology of the polymer film and the size, size distribution, and properties of the core nanoparticles (photoluminescence, magnetic) may lead to major technological breakthroughs in a variety of applications including drug delivery, ultrasensitive detectors, and chemical and biological sensors. PMID:17004754

  19. Effects of magnetic nanoparticle-incorporated human bone marrow-derived mesenchymal stem cells exposed to pulsed electromagnetic fields on injured rat spinal cord.

    PubMed

    Cho, Hyunjin; Choi, Yun-Kyong; Lee, Dong Heon; Park, Hee Jung; Seo, Young-Kwon; Jung, Hyun; Kim, Soo-Chan; Kim, Sung-Min; Park, Jung-Keug

    2013-01-01

    Transplanting mesenchymal stem cells into injured lesions is currently under study as a therapeutic approach for spinal cord injury. In this study, the effects of a pulsed electromagnetic field (PEMF) on injured rat spinal cord were investigated in magnetic nanoparticle (MNP)-incorporated human bone marrow-derived mesenchymal stem cells (hBM-MSCs). A histological analysis revealed significant differences in MNP-incorporated cell distribution near the injured site under the PEMF in comparison with that in the control group. We confirmed that MNP-incorporated cells were widely distributed in the lesions under PEMF. The results suggest that MNP-incorporated hBM-MSCs were guided by the PEMF near the injured site, and that PEMF exposure for 8 H per day over 4 weeks promoted behavioral recovery in spinal cord injured rats. The results show that rats with MNP-incorporated hBM-MSCs under a PEMF were more effective on the Basso, Beattie, and Bresnahan behavioral test and suggest that the PEMF enhanced the action of transplanted cells for recovery of the injured lesion. PMID:24033637

  20. Dietary Compound Kaempferol Inhibits Airway Thickening Induced by Allergic Reaction in a Bovine Serum Albumin-Induced Model of Asthma

    PubMed Central

    Shin, Daekeun; Park, Sin-Hye; Choi, Yean-Jung; Kim, Yun-Ho; Antika, Lucia Dwi; Habibah, Nurina Umy; Kang, Min-Kyung; Kang, Young-Hee

    2015-01-01

    Asthma is characterized by aberrant airways including epithelial thickening, goblet cell hyperplasia, and smooth muscle hypertrophy within the airway wall. The current study examined whether kaempferol inhibited mast cell degranulation and prostaglandin (PG) release leading to the development of aberrant airways, using an in vitro model of dinitrophenylated bovine serum albumin (DNP-BSA)-sensitized rat basophilic leukemia (RBL-2H3) mast cells and an in vivo model of BSA-challenged asthmatic mice. Nontoxic kaempferol at 10–20 μM suppressed β-hexosaminidase release and cyclooxygenase 2 (COX2)-mediated production of prostaglandin D2 (PGD2) and prostaglandin F2α (PGF2α) in sensitized mast cells. Oral administration of ≤20 mg/kg kaempferol blocked bovine serum albumin (BSA) inhalation-induced epithelial cell excrescence and smooth muscle hypertrophy by attenuating the induction of COX2 and the formation of PGD2 and PGF2α, together with reducing the anti-α-smooth muscle actin (α-SMA) expression in mouse airways. Kaempferol deterred the antigen-induced mast cell activation of cytosolic phospholipase A2 (cPLA2) responsive to protein kinase Cμ (PKCμ) and extracellular signal-regulated kinase (ERK). Furthermore, the antigen-challenged activation of Syk-phospholipase Cγ (PLCγ) pathway was dampened in kaempferol-supplemented mast cells. These results demonstrated that kaempferol inhibited airway wall thickening through disturbing Syk-PLCγ signaling and PKCμ-ERK-cPLA2-COX2 signaling in antigen-exposed mast cells. Thus, kaempferol may be a potent anti-allergic compound targeting allergic asthma typical of airway hyperplasia and hypertrophy. PMID:26694364

  1. Dietary Compound Kaempferol Inhibits Airway Thickening Induced by Allergic Reaction in a Bovine Serum Albumin-Induced Model of Asthma.

    PubMed

    Shin, Daekeun; Park, Sin-Hye; Choi, Yean-Jung; Kim, Yun-Ho; Antika, Lucia Dwi; Habibah, Nurina Umy; Kang, Min-Kyung; Kang, Young-Hee

    2015-01-01

    Asthma is characterized by aberrant airways including epithelial thickening, goblet cell hyperplasia, and smooth muscle hypertrophy within the airway wall. The current study examined whether kaempferol inhibited mast cell degranulation and prostaglandin (PG) release leading to the development of aberrant airways, using an in vitro model of dinitrophenylated bovine serum albumin (DNP-BSA)-sensitized rat basophilic leukemia (RBL-2H3) mast cells and an in vivo model of BSA-challenged asthmatic mice. Nontoxic kaempferol at 10-20 ?M suppressed ?-hexosaminidase release and cyclooxygenase 2 (COX2)-mediated production of prostaglandin D2 (PGD2) and prostaglandin F2? (PGF2?) in sensitized mast cells. Oral administration of ?20 mg/kg kaempferol blocked bovine serum albumin (BSA) inhalation-induced epithelial cell excrescence and smooth muscle hypertrophy by attenuating the induction of COX2 and the formation of PGD2 and PGF2?, together with reducing the anti-?-smooth muscle actin (?-SMA) expression in mouse airways. Kaempferol deterred the antigen-induced mast cell activation of cytosolic phospholipase A2 (cPLA2) responsive to protein kinase C? (PKC?) and extracellular signal-regulated kinase (ERK). Furthermore, the antigen-challenged activation of Syk-phospholipase C? (PLC?) pathway was dampened in kaempferol-supplemented mast cells. These results demonstrated that kaempferol inhibited airway wall thickening through disturbing Syk-PLC? signaling and PKC?-ERK-cPLA2-COX2 signaling in antigen-exposed mast cells. Thus, kaempferol may be a potent anti-allergic compound targeting allergic asthma typical of airway hyperplasia and hypertrophy. PMID:26694364

  2. Fabrication of hybrid nanocomposite scaffolds by incorporating ligand-free hydroxyapatite nanoparticles into biodegradable polymer scaffolds and release studies

    PubMed Central

    Farkas, Balazs; Rodio, Marina; Romano, Ilaria; Diaspro, Alberto; Intartaglia, Romuald

    2015-01-01

    Summary We report on the optical fabrication approach of preparing free-standing composite thin films of hydroxyapatite (HA) and biodegradable polymers by combining pulsed laser ablation in liquid and mask-projection excimer laser stereolithography (MPExSL). Ligand-free HA nanoparticles were prepared by ultrafast laser ablation of a HA target in a solvent, and then the nanoparticles were dispersed into the liquid polymer resin prior to the photocuring process using MPExSL. The resin is poly(propylene fumarate) (PPF), a photo-polymerizable, biodegradable material. The polymer is blended with diethyl fumarate in 7:3 w/w to adjust the resin viscosity. The evaluation of the structural and mechanical properties of the fabricated hybrid thin film was performed by means of SEM and nanoindentation, respectively, while the chemical and degradation studies were conducted through thermogravimetric analysis, and FTIR. The photocuring efficiency was found to be dependent on the nanoparticle concentration. The MPExSL process yielded PPF thin films with a stable and homogenous dispersion of the embedded HA nanoparticles. Here, it was not possible to tune the stiffness and hardness of the scaffolds by varying the laser parameters, although this was observed for regular PPF scaffolds. Finally, the gradual release of the hydroxyapatite nanoparticles over thin film biodegradation is reported. PMID:26734513

  3. Enhanced energy transfer between Co-dopants Pyronin-Y and Thionine incorporated into modified polymethyl methacrylate with addition of ZnO nanoparticles.

    PubMed

    Vijayaraghavan, G V; Basheer Ahamed, M

    2016-04-01

    Using a prism dye cell arrangement, the study investigated spectral energy transfer between co-dopants Pyronin-Y and Thionine incorporated into ethanol-modified polymethyl methacrylate. The spectral parameters of the absorption and fluorescence spectra of the donor and acceptor dyes in the so designed solid-state dye laser were calculated theoretically. Fluorescence lasing properties and slope efficiency of the solid-state dye laser were investigated both with and without addition of ZnO nanoparticles. The dye pair generally improved lasing efficiency and tunability in the range from 582 to 689nm. PMID:26803748

  4. The anti-inflammatory effect of kaempferol on early atherosclerosis in high cholesterol fed rabbits

    PubMed Central

    2013-01-01

    Background Atherosclerosis has been widely accepted as an inflammatory disease of vascular, adhesion molecules play an important role in the early progression of it. The aim of the present study was to evaluate the effect of kaempferol on the inflammatory molecules such as E-selectin (E-sel), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesionmolecule-1 (VCAM-1) and monocyte chemotactic protein-1 (MCP-1) in high cholesterol induced atherosclerosis rabbit models. Methods Thirty male New Zealand white (NZW) rabbits were randomly divided into five groups, control group, model group, fenofibrate (12mg/kg) group and kaempferol groups (150 mg/kg and 30 mg/kg). The rabbits were fed with a normal diet or a high cholesterol diet for 10 weeks. Levels of blood lipids, serum tumour-necrosis factor-alpha (TNF-?) and serum interleukin-1beta (IL-1?) were detected at the end of the sixth and tenth week. Malonaldehyde (MDA) level and superoxide dismutase (SOD) activity in serum were also determined. Lesion areas of the aorta were measured with morphometry analysis after ten weeks. Gene expression of E-sel, ICAM-1, VCAM-1 and MCP-1 in aortas was determined by RT-PCR (reverse transcription-polymerase chain reaction). Immunohistochemical staining was employed to measure protein expression of E-sel, ICAM-1, VCAM-1 and MCP-1. Results Model rabbits fed with ten weeks of high-cholesterol diet developed significant progression of atherosclerosis. Compared with the control, levels of blood lipids, TNF-?, IL-1? and MDA increased markedly in serum of model rabbits, while SOD levels decreased. Gene and protein expressions of E-sel, ICAM-1, VCAM-1 and MCP-1 in atherosclerotic aortas increased remarkably in model group. However, comparing to the model rabbits, levels of TNF-?, IL-1? and MDA decreased significantly and serum SOD activity increased, gene and protein expressions of E-sel, ICAM-1, VCAM-1 and MCP-1 in aortas decreased significantly with the treatment of kaempferol. Conclusion Kaempferol shows anti-atherosclerotic effect by modulating the gene and protein expression of inflammatory molecules. PMID:23895132

  5. Small Molecule Kaempferol Promotes Insulin Sensitivity and Preserved Pancreatic β-Cell Mass in Middle-Aged Obese Diabetic Mice

    PubMed Central

    Alkhalidy, Hana; Moore, William; Zhang, Yanling; Wang, Aihua; Ali, Mostafa; Suh, Kyung-Shin; Zhen, Wei; Cheng, Zhiyong; Jia, Zhenquan; Hulver, Matthew

    2015-01-01

    Insulin resistance and a progressive decline in functional β-cell mass are hallmarks of developing type 2 diabetes (T2D). Thus, searching for natural, low-cost compounds to target these two defects could be a promising strategy to prevent the pathogenesis of T2D. Here, we show that dietary intake of flavonol kaempferol (0.05% in the diet) significantly ameliorated hyperglycemia, hyperinsulinemia, and circulating lipid profile, which were associated with the improved peripheral insulin sensitivity in middle-aged obese mice fed a high-fat (HF) diet. Kaempferol treatment reversed HF diet impaired glucose transport-4 (Glut4) and AMP-dependent protein kinase (AMPK) expression in both muscle and adipose tissues from obese mice. In vitro, kaempferol increased lipolysis and prevented high fatty acid-impaired glucose uptake, glycogen synthesis, AMPK activity, and Glut4 expression in skeletal muscle cells. Using another mouse model of T2D generated by HF diet feeding and low doses of streptozotocin injection, we found that kaempferol treatment significantly improved hyperglycemia, glucose tolerance, and blood insulin levels in obese diabetic mice, which are associated with the improved islet β-cell mass. These results demonstrate that kaempferol may be a naturally occurring anti-diabetic agent by improving peripheral insulin sensitivity and protecting against pancreatic β-cell dysfunction. PMID:26064984

  6. Development of Nanoparticles Incorporating a Novel Liposomal Membrane Destabilization Peptide for Efficient Release of Cargos into Cancer Cells

    PubMed Central

    Ohgita, Takashi; Kogure, Kentaro

    2014-01-01

    In anti-cancer therapy mediated by a nanoparticle-based drug delivery system (DDS), overall efficacy depends on the release efficiency of cargos from the nanoparticles in the cancer cells as well as the specificity of delivery to tumor tissue. However, conventional liposome-based DDS have no mechanism for specifically releasing the encapsulated cargos inside the cancer cells. To overcome this barrier, we developed nanoparticles containing a novel liposomal membrane destabilization peptide (LMDP) that can destabilize membranes by cleavage with intramembranous proteases on/in cancer cells. Calcein encapsulated in liposomes modified with LMDP (LMDP-lipo) was effectively released in the presence of a membrane fraction containing an LMDP-cleavable protease. The release was inhibited by a protease inhibitor, suggesting that LMDP-lipo could effectively release its cargo into cells in response to a cancer-specific protease. Moreover, when LMDP-lipo contained fusogenic lipids, the release of cargo was accelerated, suggesting that the fusion of LMDP-lipo with cellular membranes was the initial step in the intracellular delivery. Time-lapse microscopic observations showed that the release of cargo from LMDP-lipo occurred immediately after association of LMDP-lipo with target cells. Consequently, LMDP-lipo could be a useful nanoparticle capable of effective release of cargos specifically into targeted cancer cells. PMID:25343714

  7. Optimizing stem cell functions and antibacterial properties of TiO2 nanotubes incorporated with ZnO nanoparticles: experiments and modeling

    PubMed Central

    Liu, Wenwen; Su, Penglei; Gonzales, Arthur; Chen, Su; Wang, Na; Wang, Jinshu; Li, Hongyi; Zhang, Zhenting; Webster, Thomas J

    2015-01-01

    To optimize mesenchymal stem cell differentiation and antibacterial properties of titanium (Ti), nano-sized zinc oxide (ZnO) particles with tunable concentrations were incorporated into TiO2 nanotubes (TNTs) using a facile hydrothermal strategy. It is revealed here for the first time that the TNTs incorporated with ZnO nanoparticles exhibited better biocompatibility compared with pure Ti samples (controls) and that the amount of ZnO (tailored by the concentration of Zn(NO3)2 in the precursor) introduced into TNTs played a crucial role on their osteogenic properties. Not only was the alkaline phosphatase activity improved to about 13.8 U/g protein, but the osterix, collagen-I, and osteocalcin gene expressions was improved from mesenchymal stem cells compared to controls. To further explore the mechanism of TNTs decorated with ZnO on cell functions, a response surface mathematical model was used to optimize the concentration of ZnO incorporation into the Ti nanotubes for stem cell differentiation and antibacterial properties for the first time. Both experimental and modeling results confirmed (R2 values of 0.88730.9138 and 0.95960.9941, respectively) that Ti incorporated with appropriate concentrations (with an initial concentration of Zn(NO3)2 at 0.015 M) of ZnO can provide exceptional osteogenic properties for stem cell differentiation in bone cells with strong antibacterial effects, properties important for improving dental and orthopedic implant efficacy. PMID:25792833

  8. Photoacoustic molecular imaging of angiogenesis using theranostic ανβ3-targeted copper nanoparticles incorporating a sn-2 lipase-labile fumagillin prodrug

    NASA Astrophysics Data System (ADS)

    Zhang, Ruiying; Cai, Xin; Yang, Xiaoxia; Senpan, Angana; Allen, John S.; Pan, Dipanjan; Lanza, Gregory M.; Wang, Lihong V.

    2014-03-01

    Photoacoustic (PA) tomography imaging is an emerging, versatile, and noninvasive imaging modality, which combines the advantages of both optical imaging and ultrasound imaging. It opens up opportunities for noninvasive imaging of angiogenesis, a feature of skin pathologies including cancers and psoriasis. In this study, high-density copper oleate encapsulated within a phospholipid surfactant (CuNPs) generated a soft nanoparticle with PA contrast comparable to gold. Within the near-infrared window, the copper nanoparticles can provide a signal more than 7 times higher that of blood. ανβ3-targeted of CuNPs in a Matrigel mouse model demonstrated prominent PA contrast enhancement of the neovasculature compared to mice given nontargeted or competitively inhibited CuNPs. Incorporation of a sn-2 lipase-labile fumagillin prodrug into the CuNPs produced marked antiangiogenesis in the same model, demonstrating the theranostic potential of a PA agent for the first time in vivo. With a PA signal comparable to gold-based nanoparticles yet a lower cost and demonstrated drug delivery potential, ανβ3-targeted CuNPs hold great promise for the management of skin pathologies with neovascular features.

  9. ανβ3-targeted Copper Nanoparticles Incorporating an Sn 2 Lipase-Labile Fumagillin Prodrug for Photoacoustic Neovascular Imaging and Treatment

    PubMed Central

    Zhang, Ruiying; Pan, Dipanjan; Cai, Xin; Yang, Xiaoxia; Senpan, Angana; Allen, John S.; Lanza, Gregory M.; Wang, Lihong V.

    2015-01-01

    Photoacoustic (PA) tomography enables multiscale, multicontrast and high-resolution imaging of biological structures. In particular, contrast-enhanced PA imaging offers high-sensitivity noninvasive imaging of neovessel sprout formation and nascent tubules, which are important biomarkers of malignant tumors and progressive atherosclerotic disease. While gold nanoparticles or nanorods have been used as PA contrast agents, we utilized high-density copper oleate small molecules encapsulated within a phospholipid surfactant (CuNPs) to generate a soft nanoparticle with PA contrast comparable to that from gold. Within the NIR window, the copper nanoparticles provided a 4-fold higher signal than that of blood. ανβ3-integrin targeting of CuNPs in a MatrigelTM angiogenesis mouse model demonstrated prominent (p<0.05) PA contrast enhancement of the neovasculature compared with mice given nontargeted or competitively inhibited CuNPs. Furthermore, incorporation of a Sn 2 lipase-labile fumagillin prodrug into the CuNP outer lipid membrane produced marked antiangiogenesis in the same model when targeted to the ανβ3-integrin, providing proof of concept in vivo for the first targeted PA - drug delivery agent. PMID:25553103

  10. Silica sacrificial layer-assisted in-plane incorporation of Au nanoparticles into mesoporous titania thin films through different reduction methods.

    PubMed

    Liang, Chih-Peng; Yamauchi, Yusuke; Liu, Chia-Hung; Wu, Kevin C-W

    2013-06-28

    This study focuses on the incorporation of gold nanoparticles (Au NPs) into our previously synthesized mesoporous titania thin films consisting of titania nanopillars and inverse mesospace (C. W. Wu, T. Ohsuna, M. Kuwabara and K. Kuroda, J. Am. Chem. Soc., 2006, 128, 4544-4545, denoted as MTTFs). Recently, mesoporous titania materials doped with noble metals such as gold have attracted considerable attention because noble metals can enhance the efficiency of mesoporous titania-based devices. In this research, we attempted to use four different reduction methods (i.e., thermal treatment, photo irradiation, liquid immersion, and vapor contacting) to introduce gold nanoparticles (Au NPs) into MTTFs. The synthesized Au@MTTFs were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We further systematically investigated the formation mechanism of gold nanoparticles on the external and internal surfaces of the MTTFs. With the assistance of a silica sacrificial layer, well-dispersed Au NPs with sizes of 4.1 nm were obtained inside the MTTF by photo irradiation. The synthesized Au@MTTF materials show great potential in various photo-electronic and photo-catalytic applications. PMID:23633080

  11. Retinoic acid?incorporated glycol chitosan nanoparticles inhibit the expression of Ezh2 in U118 and U138 human glioma cells.

    PubMed

    Lu, Hu-Chen; Ma, Jun; Zhuang, Zong; Zhang, Yao; Cheng, Hui-Lin; Shi, Ji-Xin

    2015-11-01

    At present, one of the most life threatening types of adult brain tumor is glioblastoma multiforme (GBM). The molecular mechanism underlying the progression of GBM remains to be fully elucidated. The modern method of clinical treatment has only improved the average survival rates of a newly diagnosed patients with GBM by ~15 months. Therefore, the discovery of novel molecules, which are involved in glioma inhibition is required. In the present study, U118 and U138 human glioma cells were transfected with all?trans retinoic acid (RA)-incorporated glycol chitosan (GC) nanoparticles.An MTT assay was used for the analysis of cell proliferation and flow cytometric analysis and ssDNA detection assays were performed for the determination of induction of cell apoptosis. Cell cycle distribution was analyzed by flow cytometry. Exposure of the U118 and U138 human glioma cells to the RA?incorporated GC nanoparticles for 24 h resulted in a concentration?dependent inhibition of cell proliferation. Among the range of experimental RA concentrations, the minimum effective treatment concentration was 10 M, with a half maximal inhibitory concentration of 25 M. The results also demonstrated that RA transfection resulted in the inhibition of cell proliferation, inhibition of the expression of Ezh2, and apoptosis through the mitochondrial signaling pathway by a decrease in membrane potential, the release of cytochrome c, and cell cycle arrest in the G0/G1 phase. PMID:26351866

  12. Retinoic acid-incorporated glycol chitosan nanoparticles inhibit the expression of Ezh2 in U118 and U138 human glioma cells

    PubMed Central

    LU, HU-CHEN; MA, JUN; ZHUANG, ZONG; ZHANG, YAO; CHENG, HUI-LIN; SHI, JI-XIN

    2015-01-01

    At present, one of the most life threatening types of adult brain tumor is glioblastoma multiforme (GBM). The molecular mechanism underlying the progression of GBM remains to be fully elucidated. The modern method of clinical treatment has only improved the average survival rates of a newly diagnosed patients with GBM by ~15 months. Therefore, the discovery of novel molecules, which are involved in glioma inhibition is required. In the present study, U118 and U138 human glioma cells were transfected with all-trans retinoic acid (RA)-incorporated glycol chitosan (GC) nanoparticles. An MTT assay was used for the analysis of cell proliferation and flow cytometric analysis and ssDNA detection assays were performed for the determination of induction of cell apoptosis. Cell cycle distribution was analyzed by flow cytometry. Exposure of the U118 and U138 human glioma cells to the RA-incorporated GC nanoparticles for 24 h resulted in a concentration-dependent inhibition of cell proliferation. Among the range of experimental RA concentrations, the minimum effective treatment concentration was 10 M, with a half maximal inhibitory concentration of 25 M. The results also demonstrated that RA transfection resulted in the inhibition of cell proliferation, inhibition of the expression of Ezh2, and apoptosis through the mitochondrial signaling pathway by a decrease in membrane potential, the release of cytochrome c, and cell cycle arrest in the G0/G1 phase. PMID:26351866

  13. Sustained release of PTX-incorporated nanoparticles synergized by burst release of DOX⋅HCl from thermosensitive modified PEG/PCL hydrogel to improve anti-tumor efficiency.

    PubMed

    Xu, Shuxin; Wang, Weiwei; Li, Xijing; Liu, Jianping; Dong, Anjie; Deng, Liandong

    2014-10-01

    As drug therapies become increasingly sophisticated, the synergistic benefits of two or more drugs are often required. In this study, we aimed at improving anti-tumor efficiency of paclitaxel (PTX)-incorporated thermo-sensitive injectable hydrogel by the synergy of burst release of doxorubicin hydrochloride (DOX⋅HCl). Thermosensitive injectable hydrogel composed of nanoparticles assembled from amphiphilic copolymer poly(ε-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly(ε-caprolaone-co-1,4,8-trioxa[4.6]spiro-9-undecanone) (PECT) was fabricated. Hydrophobic PTX and hydrophilic DOX⋅HCl were loaded simultaneously in the thermo-sensitive injectable hydrogel by a two-stage entrapment. Thermosensitive gelling behaviors of drug-loading PECT nanoparticle aqueous dispersions were studied. In vitro release profiles of PTX and DOX⋅HCl and in vivo anti-tumor effect by dual drugs from PECT hydrogel were investigated. The results showed that hydrophilic and hydrophobic drugs could be successfully entrapped in PECT hydrogel simultaneously without affecting its thermo-sensitive behavior. In vitro release profiles demonstrated the burst release of DOX⋅HCl and the sustained release of PTX. Anti-tumor effect was improved by a fast and tense attack caused by the burst release of hydrophilic DOX⋅HCl from hydrogel, which was continued by the sequent sustained release of PTX-incorporated nanoparticles and remnant DOX⋅HCl. Unintentionally, entrapped in PECT hydrogel, hydrophilic DOX⋅HCl was observed to have a sustained releasing pattern in vitro and in vivo. PMID:24931190

  14. Modulation of drug resistance in Staphylococcus aureus by a kaempferol glycoside from Herissantia tiubae (Malvaceae).

    PubMed

    Falco-Silva, Vivyanne S; Silva, Davi A; Souza, Maria de Ftima V; Siqueira-Junior, Jos P

    2009-10-01

    In an ongoing project to evaluate natural compounds isolated from plants from the Brazilian biodiversity as modulators of antibiotic resistance, kaempferol-3-O-beta-d-(6''-E-p-coumaroyl) glucopyranoside (tiliroside), isolated from Herissantia tiubae (Malvaceae) was investigated using the strain SA-1199B of Staphylococcus aureus, which overexpresses the norA gene encoding the NorA efflux protein which extrudes hydrophilic fluorquinolones and some biocides, such as benzalkonium chloride, cetrimide, acriflavine and ethidium bromide. The minimum inhibitory concentrations (MICs) of the antibiotics and biocides were determined by the microdilution assay in the absence and in the presence of sub-inhibitory concentration of tiliroside. Although tiliroside did not display relevant antibacterial activity (MIC = 256 microg/mL), it modulated the activity of antibiotics, i.e. in combination with antibiotics a reduction in the MIC was observed for norfloxacin (16-fold), ciprofloxacin (16-fold), lomefloxacin (four-fold) and ofloxacin (two-fold), and an impressive reduction in the MICs for the biocides (up to 128-fold). The results presented here represent the first report of a kaempferol glycoside as a putative efflux pump inhibitor in bacteria. The present finding indicates that H. tiubae (and broadly Malvaceae) could serve as a source of plant-derived natural products that modulate bacterial resistance, i.e. a source of potential adjuvants of antibiotics. PMID:19224523

  15. Kaempferol Identified by Zebrafish Assay and Fine Fractionations Strategy from Dysosma versipellis Inhibits Angiogenesis through VEGF and FGF Pathways

    PubMed Central

    Liang, Fang; Han, Yuxiang; Gao, Hao; Xin, Shengchang; Chen, Shaodan; Wang, Nan; Qin, Wei; Zhong, Hanbing; Lin, Shuo; Yao, Xinsheng; Li, Song

    2015-01-01

    Natural products are a rich resource for the discovery of therapeutic substances. By directly using 504 fine fractions from isolated traditional Chinese medicine plants, we performed a transgenic zebrafish based screen for anti-angiogenesis substances. One fraction, DYVE-D3, was found to inhibit the growth of intersegmental vessels in the zebrafish vasculature. Bioassay-guided isolation of DYVE-D3 indicates that the flavonoid kaempferol was the active substance. Kaempferol also inhibited the proliferation and migration of HUVECs in vitro. Furthermore, we found that kaempferol suppressed angiogenesis through inhibiting VEGFR2 expression, which can be enhanced by FGF inhibition. In summary, this study shows that the construction of fine fraction libraries allows efficient identification of active substances from natural products. PMID:26446489

  16. Kaempferol as Selective Human MAO-A Inhibitor: Analytical Detection in Calabrian Red Wines, Biological and Molecular Modeling Studies.

    PubMed

    Gidaro, Maria Concetta; Astorino, Christian; Petzer, Anél; Carradori, Simone; Alcaro, Francesca; Costa, Giosuè; Artese, Anna; Rafele, Giancarlo; Russo, Francesco M; Petzer, Jacobus P; Alcaro, Stefano

    2016-02-17

    The purpose of this work was to determine the kaempferol content in three red wines of Calabria, a southern Italian region with a great number of certified food products. Considering that wine cultivar, climate, and soil influence the qualitative and quantitative composition in flavonoids of Vitis vinifera L. berries, the three analyzed samples were taken from the 2013 vintage. Moreover, the Gaglioppo samples, with assigned Controlled Origin Denomination (DOC), were also investigated in the production of years 2008, 2010, and 2011. In addition to the analysis of kaempferol, which is present in higher concentration than in other Italian wines, in vitro assays were performed to evaluate, for the first time, the inhibition of the human monoamine oxidases (hMAO-A and hMAO-B). Molecular recognition studies were also carried out to provide insight into the binding mode of kaempferol and selectivity of inhibition of the hMAO-A isoform. PMID:26821152

  17. Selective detection toward quercetin and kaempferol on NH3-plasma treated carbon nanotubes modified glassy carbon electrode.

    PubMed

    Song, Jing-Jing; Lu, Yong; Zhu, Si-Wei; Huang, Qin-An; Wei, Yan

    2015-01-01

    NH3-plasma treated multi-walled carbon nanotubes (pn-MWCNTs) were prepared based on the plasma technique and developed as sensing materials for detection of quercetin and kaempferol with the differential pulse voltammetry (DPV) and amperometric measurement. Such experimental parameters as pH values, accumulation potential and accumulation time were carefully investigated. The pn-MWCNTs modified electrode (pn-MWCNTs/GCE) was further explored for the analysis of quercetin and kaempferol in diluted blood serum and average recovery rates of 96.91 and 100.5% were obtained, respectively. In addition, the interference and stability measurements were evaluated under the optimized experimental conditions. More importantly, selective detection toward quercetin and kaempferol was achieved, and the proposed electrochemical sensing strategy was available to distinguish substances with similar oxidation potential. PMID:25765278

  18. Kaempferol Identified by Zebrafish Assay and Fine Fractionations Strategy from Dysosma versipellis Inhibits Angiogenesis through VEGF and FGF Pathways.

    PubMed

    Liang, Fang; Han, Yuxiang; Gao, Hao; Xin, Shengchang; Chen, Shaodan; Wang, Nan; Qin, Wei; Zhong, Hanbing; Lin, Shuo; Yao, Xinsheng; Li, Song

    2015-01-01

    Natural products are a rich resource for the discovery of therapeutic substances. By directly using 504 fine fractions from isolated traditional Chinese medicine plants, we performed a transgenic zebrafish based screen for anti-angiogenesis substances. One fraction, DYVE-D3, was found to inhibit the growth of intersegmental vessels in the zebrafish vasculature. Bioassay-guided isolation of DYVE-D3 indicates that the flavonoid kaempferol was the active substance. Kaempferol also inhibited the proliferation and migration of HUVECs in vitro. Furthermore, we found that kaempferol suppressed angiogenesis through inhibiting VEGFR2 expression, which can be enhanced by FGF inhibition. In summary, this study shows that the construction of fine fraction libraries allows efficient identification of active substances from natural products. PMID:26446489

  19. Skin moisturizing effect and skin penetration of ascorbyl palmitate entrapped in solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) incorporated into hydrogel.

    PubMed

    Uner, M; Wissing, S A; Yener, G; Mller, R H

    2005-10-01

    This study was performed as a complimentary to our previous study regarding the chemical stability of ascorbyl palmitate (AP) in solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and for comparison, in nanoemulsion (NE) incorporated into a hydrogel produced by high pressure homogenization. AP is known as an effective antioxidant that protects tissue integrity similar to vitamin C. Recently, its moisturizing activity in conventional topical formulations was found to be high. The aim of the present study was to investigate the moisturizing potential of AP in SLN and NLC incorporated into hydrogel as colloidal carrier systems. It has been known that SLN and NLC have occlusive effects, but AP incorporation moisturized skin significantly better than placebo in short-term (p < 0.001) and long-term trials (p < 0.01) for both SLN and NLC. In the second part of the study, SLN and NLC were found to sustain the penetration of AP through excised human skin about 1/2 and 2/3 times compared to NE (p < 0.001 and p < 0.01), respectively, due to the solid state of Witepsol E85 in the lipid phase. PMID:16259122

  20. Anti-diabetic effects of a kaempferol glycoside-rich fraction from unripe soybean (Edamame, Glycine max L. Merrill. 'Jindai') leaves on KK-A(y) mice.

    PubMed

    Zang, Yanqing; Sato, Hideyo; Igarashi, Kiharu

    2011-01-01

    The anti-diabetic effects of a kaempferol glycoside-rich fraction (KG) prepared from leaves of unripe Jindai soybean (Edamame) and kaempferol, an aglycone of kaempferol glycoside, were determined in genetically type 2 diabetic KK-A(y) mice. The hemoglobin A(₁c) level was decreased and tended to be decreased by respectively feeding KG and kaempferol (K). The area under the curve (AUC) in the oral glucose tolerance test (OGTT) tended to be decreased by feeding K and KG. The liver triglyceride level and fatty acid synthase activity were both decreased in the mice fed with KG and K when compared to those parameters in the control mice. These results suggest that KG and K would be useful to improve the diabetes condition. The major flavonoids in KG were identified as kaempferol 3-O-β-D-glucopyranosyl(1→2)-O-[α-L-rhamnopyranosyl(1→6)]-β-D-galactopyranoside, kaempferol 3-O-β-D-glucopyranosyl(1→2)-O-[α-L-rhamnopyranosyl(1→6)]-β-D-glucopyranoside, kaempferol 3-O-β-D-(2-O-β-D-glucopyranosyl) galactopyranoside and kaempferol 3-O-β-D-(2,6-di-O-α-L-rhamnopyranosyl) galactopyronoside, suggesting that these compounds or some of them may be concerned with mitigation of diabetes. PMID:21897048

  1. ENHANCED GENE DELIVERY IN PORCINE VASCULATURE TISSUE FOLLOWING INCORPORATION OF ADENO-ASSOCIATED VIRUS NANOPARTICLES INTO POROUS SILICON MICROPARTICLES

    PubMed Central

    McConnell, Kellie I.; Rhudy, Jessica; Yokoi, Kenji; Gu, Jianhua; Mack, Aaron; Suh, Junghae; La Francesca, Saverio; Sakamoto, Jason; Serda, Rita E.

    2014-01-01

    There is an unmet clinical need to increase lung transplant successes, patient satisfaction and to improve mortality rates. We offer the development of a nanovector-based solution that will reduce the incidence of lung ischemic reperfusion injury (IRI) leading to graft organ failure through the successful ex vivo treatment of the lung prior to transplantation. The innovation is in the integrated application of our novel porous silicon (pSi) microparticles carrying adeno-associated virus (AAV) nanoparticles, and the use of our ex vivo lung perfusion/ventilation system for the modulation of pro-inflammatory cytokines initiated by ischemic pulmonary conditions prior to organ transplant that often lead to complications. Gene delivery of anti-inflammatory agents to combat the inflammatory cascade may be a promising approach to prevent IRI following lung transplantation. The rationale for the device is that the microparticle will deliver a large payload of virus to cells and serve to protect the AAV from immune recognition. The microparticle-nanoparticle hybrid device was tested both in vitro on cell monolayers and ex vivo using either porcine venous tissue or a pig lung transplantation model, which recapitulates pulmonary IRI that occurs clinically post-transplantation. Remarkably, loading AAV vectors into pSi microparticles increases gene delivery to otherwise non-permissive endothelial cells. PMID:25180449

  2. Kaempferol stimulates large conductance Ca2+-activated K+ (BKCa) channels in human umbilical vein endothelial cells via a cAMP/PKA-dependent pathway

    PubMed Central

    Xu, Y C; Leung, G P H; Wong, P Y D; Vanhoutte, P M; Man, R Y K

    2008-01-01

    Background and purpose: Kaempferol has been shown to possess a vasodilator effect but its mechanism of action remains unclear. In this study, experiments were carried out to study the effect of kaempferol on K+ channels in endothelial cells. Experimental approach: K+ channel activities in human umbilical vein endothelial cells (HUVECs) were studied by conventional whole cell and cell-attached patch-clamp electrophysiology. Key results: Kaempferol stimulated an outward-rectifying current in HUVECs in a dose-dependent manner with an EC50 value of 2.50.02??M. This kaempferol-induced current was abolished by large conductance Ca2+-activated K+ (BKCa) channel blockers, such as iberiotoxin (IbTX) and charybdotoxin (ChTX), whereas the small conductance Ca2+-activated K+ (SKCa) channel blocker, apamin, and the voltage-dependent K+ (KV) channel blocker, 4-aminopyridine, had no effect. Cell-attached patches demonstrated that kaempferol increased the open probability of BkCa channels in HUVECs. Clamping intracellular Ca2+ did not prevent kaempferol-induced increases in outward current. In addition, the kaempferol-induced current was diminished by the adenylyl cyclase inhibitor SQ22536, the cAMP antagonist Rp-8-Br-cAMP and the PKA inhibitor KT5720, but was not affected by the guanylyl cyclase inhibitor ODQ, the cGMP antagonist Rp-8-Br-cGMP and the PKG inhibitor KT5823. The activation of BKCa channels by kaempferol caused membrane hyperpolarization of HUVECs. Conclusion and implications: These results demonstrate that kaempferol activates the opening of BKCa channels in HUVECs via a cAMP/PKA-dependent pathway, resulting in membrane hyperpolarization. This mechanism may partly account for the vasodilator effects of kaempferol. PMID:18493242

  3. Study of Kaempferol Glycoside as an Insulin Mimic Reveals Glycon To Be the Key Active Structure

    PubMed Central

    2010-01-01

    Diabetes mellitus is increasing in prevalence with patient numbers rising throughout the world. Current treatments for diabetes mellitus focus on control of blood glucose levels. Certain kinds of flavonoids or their glycosides stimulate cells to improve glucose uptake and lower blood glucose levels. We synthesized kaempferol 3-O-neohesperidoside (1), a naturally occurring substance present in Cyathea phalerata Mart., reported to mimic the action of insulin. Synthetic 1 promoted glucose uptake in the cultured cell line, L6. Further studies to determine the core structure responsible for this activity using synthetic compounds revealed neohesperidose to be the primary pharmacophore. These findings support the use of certain saccharides as a potential novel treatment for diabetes mellitus by replacing or supporting insulin. PMID:24900249

  4. In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells

    PubMed Central

    Lim, Su Pei; Pandikumar, Alagarsamy; Lim, Yee Seng; Huang, Nay Ming; Lim, Hong Ngee

    2014-01-01

    This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30?nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I3?/I? redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs. PMID:24930387

  5. In-situ electrochemically deposited polypyrrole nanoparticles incorporated reduced graphene oxide as an efficient counter electrode for platinum-free dye-sensitized solar cells.

    PubMed

    Lim, Su Pei; Pandikumar, Alagarsamy; Lim, Yee Seng; Huang, Nay Ming; Lim, Hong Ngee

    2014-01-01

    This paper reports a rapid and in-situ electrochemical polymerization method for the fabrication of polypyrrole nanoparticles incorporated reduced graphene oxide (rGO@PPy) nanocomposites on a ITO conducting glass and its application as a counter electrode for platinum-free dye-sensitized solar cell (DSSC). The scanning electron microscopic images show the uniform distribution of PPy nanoparticles with diameter ranges between 20 and 30 nm on the rGO sheets. The electrochemical studies reveal that the rGO@PPy has smaller charge transfer resistance and similar electrocatalytic activity as that of the standard Pt counter electrode for the I?(-)/I(-) redox reaction. The overall solar to electrical energy conversion efficiency of the DSSC with the rGO@PPy counter electrode is 2.21%, which is merely equal to the efficiency of DSSC with sputtered Pt counter electrode (2.19%). The excellent photovoltaic performance, rapid and simple fabrication method and low-cost of the rGO@PPy can be potentially exploited as a alternative counter electrode to the expensive Pt in DSSCs. PMID:24930387

  6. Simultaneous determination by HPLC of quercetin and kaempferol in three Sedum medicinal plants harvested in different seasons.

    PubMed

    Wang, Luyao; Mei, Qing; Wan, Dingrong

    2014-04-01

    A high-performance liquid chromatography method was established for the fast quantification of quercetin and kaempferol in three Sedum crude medicines: Sedi Herba (Sedum sarmentosum Bunge.), Sedi Linearis Herba (Sedum lineare Thunb.) and Sedi Emarginati Herba (Sedum emarginatum Migo.). The column used was a YMC-pack ODS-A (250 4.6 mm, 5 m), the mobile phase was a solution of methanol-0.4% phosphoric acid (47:53) with a flow rate of 1.0 mL/min at 35C and the detection wavelength was 360 nm. The calibration curves for quercetin and kaempferol were linear over the range of 0.01-0.62 g for quercetin and 0.02-0.78 g for kaempferol, and the average recoveries were 99.72% [relative standard deviation (RSD): 1.63% and 99.50% (RSD: 1.16%), respectively]. In conclusion, the method established in this paper is accurate and repeatable. It can be used for the determination of quercetin and kaempferol, controlling the quality of the three crude drugs. Furthermore, the experimental data showed that the best harvest season for the three Sedum medicinal species should be the full-bloom period between the end of April and the beginning of May. PMID:23572321

  7. Kaempferol Glycosides and Enzymes of Flavonol Biosynthesis in Leaves of a Soybean Strain with Low Photosynthetic Rates

    PubMed Central

    Cosio, Eric G.; McClure, Jerry W.

    1984-01-01

    Soybean (Glycine max L.) strains which accumulate kaempferol 3-(2G-glucosylgentiobioside) in their leaves fix CO2 at rates significantly lower than those lacking this compound (Buttery, Buzzell 1976 Crop Sci 16: 547-550), and kaempferol aglycone is a well known inhibitor of photosynthesis in vitro. However, since neither kaempferol nor any of its glycosides could be detected in mesophyll cells isolated from mature soybean leaves we suspect that kaempferol 3-(2G-glucosylgentiobioside) has no direct inhibitory effect on photosynthesis. The most rapid stage of flavonoid accumulation, and the highest level of activity for several enzymes of phenolic biosynthesis, occurs in leaflets 2.5 to 3 centimeters long. Mesophyll cells isolated from these leaflets contain about 70% of the whole leaf activity for shikimate dehydrogenase, 24% of the 4-coumarate:CoA ligase activity, 35% of the activity for chalcone-flavanone isomerase, but no demonstrable activity for phenylalanine ammonialyase. Our results suggest a highly tissue-specific pattern of secondary phenolic metabolism in soybean leaves. PMID:16663526

  8. Possible mechanism(s) behind recently observed effects of incorporating gold nanoparticles into a polymer-dispersed liquid crystal

    NASA Astrophysics Data System (ADS)

    Hinojosa, Alfonso; Sharma, Suresh

    2010-10-01

    Recently we reported that addition of relatively small concentrations of about 14-nm diameter gold nanoparticles (Au NPs) to a polymer-dispersed liquid crystal (PDLC) produces rather large changes in the electro-optical properties of the PDLC. For example, addition of Au NPs to PDLC microstructure lowers its threshold voltage by almost 50% and increases optical transmission in a manner that depends on NPs concentration and applied electric field.ootnotetextA. Hinojosa and S. C. Sharma, Applied Physics Letters, 97, 081114 (2010) In order to understand these observations, we have carried out electro-optical measurements on several PDLCs as functions of the polarization of the incident laser beam and applied electric field. In this presentation, we will discuss the results obtained from these experiments and suggest mechanism(s), which might explain NPs-induced changes in the electro-optical properties of PDLCs.

  9. The incorporation of silver nanoparticles in samarium doped magnesium tellurite glass: Effect on the characteristic of bonding and local structure

    NASA Astrophysics Data System (ADS)

    Yusoff, N. M.; Sahar, M. R.

    2015-08-01

    Samarium doped magnesium tellurite glass with and without silver nanoparticles is prepared using melt quenching technique. All glasses are amorphous in nature. The existence of silver nanoparticles in a glass matrix with an average size of 16.94 nm has been confirmed by Transmission Electron Microscopy. The UV-vis spectra are complemented with Judd-Ofelt calculation to get the Judd-Ofelt intensity parameters. It has also been used to calculate nephelauxetic ratio, bonding parameter and Racah parameters. It is found that Judd-Ofelt intensity parameters ?2 ,?4 and ?6 increase with an increase of Ag NPs contents up to 0.2 mol% and decrease thereafter. Nephelauxetic ratio, ? decreases with increasing the concentration of Ag NPs, while bonding parameter, ? increases as the concentration of Ag NPs increases. The value of Racah parameters decreases as the concentration of Ag NPs increases. Fourier Transform Infrared (FTIR) and Raman spectroscopy have been manipulated to observe the structural modification of [TeO4] trigonal bipyramidal structural unit. In the FTIR spectrum, it is found that the structural unit of [TeO4] trigonal bipyramidal, [TeO3+1] polyhedral and/or [TeO3] trigonal pyramidal groups are located at 651-663 cm-1 and 772 cm-1, respectively. It is observed that the [TeO4] tbp wavenumber shifts to a higher wavenumber as the concentration of Ag NPs increases up to 0.2 mol% and decreases thereafter. Meanwhile, for the Raman spectra, it is found that [TeO4] tbp, [TeO3+1] polyhedral and [TeO3] tp groups are located at 646-666 cm-1, 714-741 cm-1, and 745-772 cm-1, respectively.

  10. In vitro biocompatibility and antibacterial efficacy of a degradable poly(L-lactide-co-epsilon-caprolactone) copolymer incorporated with silver nanoparticles.

    PubMed

    Samberg, Meghan E; Mente, Peter; He, Ting; King, Martin W; Monteiro-Riviere, Nancy A

    2014-07-01

    Silver nanoparticles (Ag-nps) are currently used as a natural biocide to prevent undesired bacterial growth in clothing, cosmetics and medical products. The objective of the study was to impart antibacterial properties through the incorporation of Ag-nps at increasing concentrations to electrospun degradable 50:50 poly(L-lactide-co-epsilon-caprolactone) scaffolds for skin tissue engineering applications. The biocompatibility of the scaffolds containing Ag-nps was evaluated with human epidermal keratinocytes (HEK); cell viability and proliferation were evaluated using Live/Dead and alamarBlue viability assays following 7 and 14days of cell culture on the scaffolds. Significant decreases in cell viability and proliferation were noted for the 1.0mg(Ag) g(scaffold)(-1) after 7 and 14days on Ag-nps scaffolds. After 14days, scanning electron microscopy revealed a confluent layer of HEK on the surface of the 0.0 and 0.1mg(Ag) g(scaffold)(-1). Both 0.5 and 1.0mg(Ag) g(scaffold)(-1) were capable of inhibiting both Gram positive and negative bacterial strains. Uniaxial tensile tests revealed a significant (p<0.001) decrease in the modulus of elasticity following Ag-nps incorporation compared to control. These findings suggest that a scaffold containing between 0.5 and 1.0mg(Ag) g(scaffold)(-1) is both biocompatible and antibacterial, and is suitable for skin tissue engineering graft scaffolds. PMID:24150238

  11. In Vitro Biocompatibility and Antibacterial Efficacy of a Degradable Poly(L-lactide-co-epsilon-caprolactone) Copolymer Incorporated with Silver Nanoparticles

    PubMed Central

    Samberg, Meghan E.; Mente, Peter; He, Ting; King, Martin W.; Monteiro-Riviere, Nancy A.

    2014-01-01

    Silver nanoparticles (Ag-nps) are currently used as a natural biocide to prevent undesired bacterial growth in clothing, cosmetics and medical products. The objective of the study was to impart antibacterial properties through the incorporation of Ag-nps at increasing concentrations to electrospun degradable 50:50 poly(L-lactide-co-epsilon-caprolactone) scaffolds for skin tissue engineering applications. The biocompatibility of the scaffolds containing Ag-nps was evaluated with human epidermal keratinocytes (HEK); cell viability and proliferation were evaluated using Live/Dead and alamarBlue viability assays following 7 and 14 days of cell culture on the scaffolds. Significant decreases in cell viability and proliferation were noted for the 1.0 mg(Ag) g(scaffold)?1 after 7 and 14 days on Ag-nps scaffolds. After 14 days, scanning electron microscopy revealed a confluent layer of HEK on the surface of the 0.0 and 0.1 mg(Ag) g(scaffold)?1. Both 0.5 and 1.0 mg(Ag) g(scaffold)?1 were capable of inhibiting both Gram positive and negative bacterial strains. Uniaxial tensile tests revealed a significant (p < 0.001) decrease in the modulus of elasticity following Ag-nps incorporation compared to control. These findings suggest that a scaffold containing between 0.5 and 1.0 mg(Ag) g(scaffold)?1 is both biocompatible and antibacterial, and is suitable for skin tissue engineering graft scaffolds. PMID:24150238

  12. A multifunctional upconverting nanoparticle incorporated polycationic hydrogel for near-infrared triggered and synergistic treatment of drug-resistant bacteria

    NASA Astrophysics Data System (ADS)

    Yin, Meili; Li, Zhenhua; Zhou, Li; Dong, Kai; Ren, Jinsong; Qu, Xiaogang

    2016-03-01

    Recently, antibiotic drug-resistant therapies have become very important due to the emergence of antibiotic-resistant bacterial strains. The development of novel antibacterial materials has received significant attention. Here, quaternized chitosan hydrogels incorporated with NaYF4:Er/Yb/Mn@photosensitizer-doped silica (UCNPs/MB) were synthesized for effective killing of both gram-positive oxacillin-resistant S. aureus (DR-S. aureus) and gram-negative kanamyclin-resistant E. coli (DR-E. coli) bacteria upon near-infrared (NIR) laser irradiation. In this system, the cationic macroporous nature of the hydrogel acts as a molecular ‘anion sponge’, which sucks the outer part of the anionic microbe membrane into the gel interior voids and causes microbe membrane disruption. By incorporating UCNPs/MB-doped silica into the hydrogel, we have combined photodynamic therapy (PDT) with quaternized chitosan to obtain a high therapeutic index via a synergistic effect. In vitro experiments have demonstrated that our system had excellent antibacterial efficiency to both DR-S. aureus and DR-E. coli bacteria. More importantly, our new synergistic treatment modality provided an excellent therapy platform for drug-resistant bacteria, which could improve antimicrobial efficiency.

  13. The effect of Ce{sup 4+} incorporation on structural, morphological and photocatalytic characters of ZnO nanoparticles

    SciTech Connect

    Kannadasan, N.; Shanmugam, N. Cholan, S.; Sathishkumar, K.; Viruthagiri, G.; Poonguzhali, R.

    2014-11-15

    We report a simple chemical precipitation method for the preparation of undoped and cerium doped ZnO nanocrystals. The concentration of cerium in the products can be controlled in the range of 0.025–0.125 mol. The structure and chemical compositions of the products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy; energy dispersive spectrum and Fourier transform infrared spectroscopy. The results demonstrate that Ce{sup 4+} ions were successfully incorporated into the lattice position of Zn{sup 2+} ions in ZnO. The morphology of the products was analyzed by field emission scanning electron microscopy and confirmed by high resolution transmission electron microscope analysis. The optical properties of the products were studied by ultraviolet–visible and room temperature photoluminescence measurements. The photoluminescence emission spectra of Ce-doped ZnO showed enhanced visible emissions as a result of 5d → 4f transition of cerium. In particular, a novel photocatalytic activity of the products was assessed using methylene blue. The obtained result reveals that Ce-doped products show higher reduction efficiency for methylene blue than the undoped ZnO. - Highlights: • Nanocrystals of ZnO and ZnO:Ce{sup 4+} were grown. • XPS results confirmed the incorporated cerium in tetravalence. • PL emission exhibited 5d → 4f transition on cerium doping. • Doped ZnO decolorizes MB faster than undoped ZnO.

  14. A multifunctional upconverting nanoparticle incorporated polycationic hydrogel for near-infrared triggered and synergistic treatment of drug-resistant bacteria.

    PubMed

    Yin, Meili; Li, Zhenhua; Zhou, Li; Dong, Kai; Ren, Jinsong; Qu, Xiaogang

    2016-03-29

    Recently, antibiotic drug-resistant therapies have become very important due to the emergence of antibiotic-resistant bacterial strains. The development of novel antibacterial materials has received significant attention. Here, quaternized chitosan hydrogels incorporated with NaYF4:Er/Yb/Mn@photosensitizer-doped silica (UCNPs/MB) were synthesized for effective killing of both gram-positive oxacillin-resistant S. aureus (DR-S. aureus) and gram-negative kanamyclin-resistant E. coli (DR-E. coli) bacteria upon near-infrared (NIR) laser irradiation. In this system, the cationic macroporous nature of the hydrogel acts as a molecular 'anion sponge', which sucks the outer part of the anionic microbe membrane into the gel interior voids and causes microbe membrane disruption. By incorporating UCNPs/MB-doped silica into the hydrogel, we have combined photodynamic therapy (PDT) with quaternized chitosan to obtain a high therapeutic index via a synergistic effect. In vitro experiments have demonstrated that our system had excellent antibacterial efficiency to both DR-S. aureus and DR-E. coli bacteria. More importantly, our new synergistic treatment modality provided an excellent therapy platform for drug-resistant bacteria, which could improve antimicrobial efficiency. PMID:26883410

  15. Incorporation of photosenzitizer hypericin into synthetic lipid-based nano-particles for drug delivery and large unilamellar vesicles with different content of cholesterol

    NASA Astrophysics Data System (ADS)

    Joniova, Jaroslava; Blascakova, Ludmila; Jancura, Daniel; Nadova, Zuzana; Sureau, Franck; Miskovsky, Pavol

    2014-08-01

    Low-density lipoproteins (LDL) and high-density lipoproteins (HDL) are attractive natural occurring vehicles for drug delivery and targeting to cancer tissues. The capacity of both types of the lipoproteins to bind hydrophobic drugs and their functionality as drug carriers have been examined in several studies and it has been also shown that mixing of anticancer drugs with LDL or HDL before administration led to an increase of cytotoxic effects of the drugs in the comparison when the drugs were administered alone. However, a difficult isolation of the lipoproteins in large quantity from a biological organism as well as a variability of the composition and size of these molecules makes practical application of LDL and HDL as drug delivery systems quite complicated. Synthetic LDL and HDL and large unilamellar vesicles (LUV) are potentially suitable candidates to substitute the native lipoproteins for targeted and effective drug delivery. In this work, we have studied process of an association of potent photosensitizer hypericin (Hyp) with synthetic lipid-based nano-particles (sLNP) and large unilamellar vesicles (LUV) containing various amount of cholesterol. Cholesterol is one of the main components of both LDL and HDL particles and its presence in biological membranes is known to be a determining factor for membrane properties. It was found that the behavior of Hyp incorporation into sLNP particles with diameter ca ~ 90 nm is qualitatively very similar to that of Hyp incorporation into LDL (diameter ca. 22 nm) and these particles are able to enter U-87 MG cells by endocytosis. The presence of cholesterol in LUV influences the capacity of these vesicles to incorporate Hyp into their structure.

  16. Effect of acid or alkaline catalyst and of different capping agents on the optical properties of CdS nanoparticles incorporated within a diureasil hybrid matrix

    NASA Astrophysics Data System (ADS)

    Gonalves, Luis F. F. F.; Silva, Carlos J. R.; Kanodarwala, Fehmida K.; Stride, John A.; Pereira, Mario R.

    2015-11-01

    CdS nanoparticles (NPs) were synthesized using colloidal methods and incorporated within a diureasil hybrid matrix. The surface capping of the CdS NPs by 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-aminopropyltrimethoxysilane (APTMS) organic ligands during the incorporation of the NPs within the hybrid matrix has been investigated. The matrix is based on poly(ethylene oxide)/poly(propylene oxide) chains grafted to a siliceous skeleton through urea bonds and was produced by sol-gel process. Both alkaline and acidic catalysis of the sol-gel reaction were used to evaluate the effect of each organic ligand on the optical properties of the CdS NPs. The hybrid materials were characterized by absorption, steady-state and time-resolved photoluminescence spectroscopy and High Resolution Transmission Electron Microscopy (HR-TEM). The preservation of the optical properties of the CdS NPs within the diureasil hybrids was dependent on the experimental conditions used. Both organic ligands (APTMS and MPTMS) demonstrated to be crucial in avoiding the increase of size distribution and clustering of the NPs within the hybrid matrix. The use of organic ligands was also shown to influence the level of interaction between the hybrid host and the CdS NPs. The CdS NPs showed large Stokes shifts and long average lifetimes, both in colloidal solution and in the xerogels, due to the origin of the PL emission in surface states. The CdS NPs capped with MPTMS have lower PL lifetimes compared to the other xerogel samples but still larger than the CdS NPs in the original colloidal solution. An increase in PL lifetimes of the NPs after their incorporation within the hybrid matrix is related to interaction between the NPs and the hybrid host matrix.

  17. Charge collection enhancement by incorporation of gold-silica core-shell nanoparticles into P3HT:PCBM/ZnO nanorod array hybrid solar cells.

    PubMed

    Wang, Ting-Chung; Su, Yen-Hsun; Hung, Yun-Kai; Yeh, Chen-Sheng; Huang, Li-Wen; Gomulya, Widianta; Lai, Lai-Hung; Loi, Maria A; Yang, Jih-Sheng; Wu, Jih-Jen

    2015-08-14

    In this work, gold-silica core-shell (Au@silica) nanoparticles (NPs) with various silica-shell thicknesses are incorporated into P3HT:PCBM/ZnO nanorod (NR) hybrid solar cells. Enhancement in the short-circuit current density and the efficiency of the hybrid solar cells is attained with the appropriate addition of Au@silica NPs regardless of the silica-shell thickness. Compared to the P3HT:PCBM/ZnO NR hybrid solar cell, a 63% enhancement in the efficiency is achieved by the P3HT:PCBM/Au@silica NP/ZnO NR hybrid solar cell. The finite difference time domain simulations indicate that the strength of the Fano resonance, i.e., the electric field of the quasi-static asymmetric quadrupole, on the surface of Au@silica NPs in the P3HT:PCBM/ZnO NR hybrid significantly decreases with increasing thickness of the silica shell. Raman characterization reveals that the degree of P3HT order increases when Au@silica NPs are incorporated into the P3HT:PCBM/ZnO NR hybrid. The charge separation at the interface between P3HT and PCBM as well as the electron transport in the active layer are retarded by the electric field of the Fano resonance. Nevertheless, the prolongation of the electron lifetime and the reduction of the electron transit time in the P3HT:PCBM/ZnO NR hybrid solar cells, which result in an enhancement of electron collection, are achieved by the addition of Au@silica NPs. This may be attributed to the improvement in the degree of P3HT order and connectivity of PCBM when Au@silica NPs are incorporated into the P3HT:PCBM active layer. PMID:26159896

  18. Effect of Cudrania tricuspidata and Kaempferol in Endoplasmic Reticulum Stress-Induced Inflammation and Hepatic Insulin Resistance in HepG2 Cells.

    PubMed

    Kim, Ok-Kyung; Jun, Woojin; Lee, Jeongmin

    2016-01-01

    In this study, we quantitated kaempferol in water extract from Cudrania tricuspidata leaves (CTL) and investigated its effects on endoplasmic reticulum (ER) stress-induced inflammation and insulin resistance in HepG2 cells. The concentration of kaempferol in the CTL was 5.07 0.08 mg/g. The HepG2 cells were treated with 300 g/mL of CTL, 500 g/mL of CTL, 1.5 g/mL of kaempferol or 2.5 g/mL of kaempferol, followed immediately by stimulation with 100 nM of thapsigargin for ER stress induction for 24 h. There was a marked increase in the activation of the ER stress and inflammation response in the thapsigargin-stimulated control group. The CTL treatment interrupted the ER stress response and ER stress-induced inflammation. Kaempferol partially inhibited the ER stress response and inflammation. There was a significant increase in serine phosphorylation of insulin receptor substrate (IRS)-1 and the expression of C/EBP? and gluconeogenic genes in the thapsigargin-stimulated control group compared to the normal control. Both CTL and kaempferol suppressed serine phosphorylation of IRS-1, and the treatments did not interrupt the C/EBP?/gluconeogenic gene pathway. These results suggest that kaempferol might be the active compound of CTL and that it might protect against ER stress-induced inflammation and hyperglycemia. PMID:26805878

  19. Anti-cancer Effect and Underlying Mechanism(s) of Kaempferol, a Phytoestrogen, on the Regulation of Apoptosis in Diverse Cancer Cell Models

    PubMed Central

    Kim, Seung-Hee

    2013-01-01

    Phytoestrogens exist in edible compounds commonly found in fruits or plants. For long times, phytoestrogens have been used for therapeutic treatments against human diseases, and they can be promising ingredients for future pharmacological industries. Kaempferol is a yellow compound found in grapes, broccoli and yellow fruits, which is one of flavonoid as phytoestrogens. Kaempferol has been suggested to have an antioxidant and anti-inflammatory effect. In past decades, many studies have been performed to examine anti-toxicological role(s) of kaempferol against human cancers. It has been shown that kaempferol may be involved in the regulations of cell cycle, metastasis, angiogenesis and apoptosis in various cancer cell types. Among them, there have been a few of the studies to examine a relationship between kaempferol and apoptosis. Thus, in this review, we highlight the effect(s) of kaempferol on the regulation of apoptosis in diverse cancer cell models. This could be a forecast in regard to use of kaempferol as promising treatment against human diseases. PMID:24578792

  20. Effect of Cudrania tricuspidata and Kaempferol in Endoplasmic Reticulum Stress-Induced Inflammation and Hepatic Insulin Resistance in HepG2 Cells

    PubMed Central

    Kim, Ok-Kyung; Jun, Woojin; Lee, Jeongmin

    2016-01-01

    In this study, we quantitated kaempferol in water extract from Cudrania tricuspidata leaves (CTL) and investigated its effects on endoplasmic reticulum (ER) stress-induced inflammation and insulin resistance in HepG2 cells. The concentration of kaempferol in the CTL was 5.07 ± 0.08 mg/g. The HepG2 cells were treated with 300 µg/mL of CTL, 500 µg/mL of CTL, 1.5 µg/mL of kaempferol or 2.5 µg/mL of kaempferol, followed immediately by stimulation with 100 nM of thapsigargin for ER stress induction for 24 h. There was a marked increase in the activation of the ER stress and inflammation response in the thapsigargin-stimulated control group. The CTL treatment interrupted the ER stress response and ER stress-induced inflammation. Kaempferol partially inhibited the ER stress response and inflammation. There was a significant increase in serine phosphorylation of insulin receptor substrate (IRS)-1 and the expression of C/EBPα and gluconeogenic genes in the thapsigargin-stimulated control group compared to the normal control. Both CTL and kaempferol suppressed serine phosphorylation of IRS-1, and the treatments did not interrupt the C/EBPα/gluconeogenic gene pathway. These results suggest that kaempferol might be the active compound of CTL and that it might protect against ER stress-induced inflammation and hyperglycemia. PMID:26805878

  1. PEGylated and poloxamer-modified chitosan nanoparticles incorporating a lysine-based surfactant for pH-triggered doxorubicin release.

    PubMed

    Scheeren, Laís E; Nogueira, Daniele R; Macedo, Letícia B; Vinardell, M Pilar; Mitjans, Montserrat; Infante, M Rosa; Rolim, Clarice M B

    2016-02-01

    The growing demand for efficient chemotherapy in many cancers requires novel approaches in target-delivery technologies. Nanomaterials with pH-responsive behavior appear to have potential ability to selectively release the encapsulated molecules by sensing the acidic tumor microenvironment or the low pH found in endosomes. Likewise, polyethylene glycol (PEG)- and poloxamer-modified nanocarriers have been gaining attention regarding their potential to improve the effectiveness of cancer therapy. In this context, DOX-loaded pH-responsive nanoparticles (NPs) modified with PEG or poloxamer were prepared and the effects of these modifiers were evaluated on the overall characteristics of these nanostructures. Chitosan and tripolyphosphate were selected to form NPs by the interaction of oppositely charged compounds. A pH-sensitive lysine-based amphiphile (77KS) was used as a bioactive adjuvant. The strong dependence of 77KS ionization with pH makes this compound an interesting candidate to be used for the design of pH-sensitive devices. The physicochemical characterization of all NPs has been performed, and it was shown that the presence of 77KS clearly promotes a pH-triggered DOX release. Accelerated and continuous release patterns of DOX from CS-NPs under acidic conditions were observed regardless of the presence of PEG or poloxamer. Moreover, photodegradation studies have indicated that the lyophilization of NPs improved DOX stability under UVA radiation. Finally, cytotoxicity experiments have shown the ability of DOX-loaded CS-NPs to kill HeLa tumor cells. Hence, the overall results suggest that these pH-responsive CS-NPs are highly potent delivery systems to target tumor and intracellular environments, rendering them promising DOX carrier systems for cancer therapy. PMID:26674840

  2. NK105, a paclitaxel-incorporating micellar nanoparticle formulation, can extend in vivo antitumour activity and reduce the neurotoxicity of paclitaxel

    PubMed Central

    Hamaguchi, T; Matsumura, Y; Suzuki, M; Shimizu, K; Goda, R; Nakamura, I; Nakatomi, I; Yokoyama, M; Kataoka, K; Kakizoe, T

    2005-01-01

    Paclitaxel (PTX) is one of the most effective anticancer agents. In clinical practice, however, high incidences of adverse reactions of the drug, for example, neurotoxicity, myelosuppression, and allergic reactions, have been reported. NK105, a micellar nanoparticle formulation, was developed to overcome these problems and to enhance the antitumour activity of PTX. Via the self-association process, PTX was incorporated into the inner core of the micelle system by physical entrapment through hydrophobic interactions between the drug and the well-designed block copolymers for PTX. NK105 was compared with free PTX with respect to their in vitro cytotoxicity, in vivo antitumour activity, pharmacokinetics, pharmacodynamics, and neurotoxicity. Consequently, the plasma area under the curve (AUC) values were approximately 90-fold higher for NK105 than for free PTX because the leakage of PTX from normal blood vessels was minimal and its capture by the reticuloendothelial system minimised. Thus, the tumour AUC value was 25-fold higher for NK105 than for free PTX. NK105 showed significantly potent antitumour activity on a human colorectal cancer cell line HT-29 xenograft as compared with PTX (P<0.001) because the enhanced accumulation of the drug in the tumour has occurred, probably followed by its effective and sustained release from micellar nanoparticles. Neurotoxicity was significantly weaker with NK105 than with free PTX. The neurotoxicity of PTX was attenuated by NK105, which was demonstrated by both histopathological (P<0.001) and physiological (P<0.05) methods for the first time. The present study suggests that NK105 warrants a clinical trial for patients with metastatic solid tumours. PMID:15785749

  3. Hybrid polymer:colloidal nanoparticle photovoltaic cells incorporating a solution-processed, multi-functioned ZnO nanocrystal layer

    NASA Astrophysics Data System (ADS)

    Yang, Jihua; Qian, Lei; Zhou, Renjia; Zheng, Ying; Tang, Aiwei; Holloway, Paul H.; Xue, Jiangeng

    2012-02-01

    We report significant improvement in both the power conversion efficiency and the environmental stability of solution-processed hybrid organic-inorganic solar cells by including a solution-processed ZnO nanocrystal layer between the photoactive layer and the cathode. For devices based on blends of poly(3-hexylthiophene) (P3HT) and mostly-spherical CdSe nanocrystals, incorporation of the ZnO layer leads to an up to 70% increase in the power conversion efficiency. Compared to only a few hours of shelf lifetime for unencapsulated devices with the metal cathode directly deposited on the hybrid active layer, devices with the ZnO layer can retain approximately 70% of the original efficiency when they are exposed to the laboratory ambient without encapsulation for more than two months. We attribute the function of this ZnO nanocrystal layer to a combination of optical, electronic, morphological, and chemical effects, including blocking leakage of photogenerated holes to the cathode, optimizing the optical intensity profile in the hybrid active layer, minimizing recombination or quenching of photogenerated excitons and charge carriers, significantly reducing the transport rate of oxygen and water molecules to the active layer and reducing degradation/oxidation of any low work function layer at the cathode interface.

  4. nanoparticles

    NASA Astrophysics Data System (ADS)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  5. Structural rearrangement of mesostructured silica nanoparticles incorporated with ZnO catalyst and its photoactivity: Effect of alkaline aqueous electrolyte concentration

    NASA Astrophysics Data System (ADS)

    Jusoh, N. W. C.; Jalil, A. A.; Triwahyono, S.; Karim, A. H.; Salleh, N. F.; Annuar, N. H. R.; Jaafar, N. F.; Firmansyah, M. L.; Mukti, R. R.; Ali, M. W.

    2015-03-01

    ZnO-incorporated mesostructured silica nanoparticles (MSN) catalysts (ZM) were prepared by the introduction of Zn ions into the framework of MSN via a simple electrochemical system in the presence of various concentrations of NH4OH aqueous solution. The physicochemical properties of the catalysts were studied by XRD, 29Si MAS NMR, nitrogen adsorption-desorption, FE-SEM, TEM, FTIR, and photoluminescence spectroscopy. Characterization results demonstrated that the alkaline aqueous electrolyte simply generated abundant silanol groups on the surface of the catalysts as a consequence of desilication to form the hierarchical-like structure of the MSN. Subsequent restructuring of the silica network by the creation of oxygen vacancies and formation of Si-O-Zn during the electrolysis, as well as formation of new Si-O-Si bonds during calcination seemed to be the main factors that enhanced the catalytic performance of photodecolorization of methyl orange. A ZM prepared in the presence of 1.0 M NH4OH (ZM-1.0) was determined to be the most effective catalyst. The catalyst displays a higher first-order kinetics rate of 3.87 × 10-1 h-1 than unsupported ZnO (1.13 × 10-1 h-1) that prepared under the same conditions in the absence of MSN. The experiment on effect of scavengers showed that hydroxyl radicals generated from the three main sources; reduced O2 at the conduction band, decomposed water at the valence band and irradiated H2O2 in the solution, are key factors that influenced the reaction. It is also noted that the recycled ZM-1.0 catalyst maintained its activity up to five runs without serious catalyst deactivation.

  6. Photothermally actuated interfacial hydration for fast friction switch on hydrophilic polymer brush modified PDMS sheet incorporated with Fe3O4 nanoparticles.

    PubMed

    Liu, Guoqiang; Cai, Meirong; Feng, Yange; Wang, Xiaolong; Zhou, Feng; Liu, Weimin

    2016-02-23

    A near-infrared light triggered fast interfacial friction switch was achieved with polyelectrolyte brush grafted PDMS embedded with Fe3O4 nanoparticles, where the in situ heating up of the photothermal Fe3O4 nanoparticles in the polymer matrix changes the interface humidity and thereafter alters the hydration level of the interfacial polymer brushes. PMID:26856309

  7. Improving the MR Imaging Sensitivity of Upconversion Nanoparticles by an Internal and External Incorporation of the Gd(3+) Strategy for in Vivo Tumor-Targeted Imaging.

    PubMed

    Du, Hongli; Yu, Jiani; Guo, Dongcai; Yang, Weitao; Wang, Jun; Zhang, Bingbo

    2016-02-01

    Gd(3+)-ion-doped upconversion nanoparticles (UCNPs), integrating the advantages of upconversion luminescence and magnetic resonance imaging (MRI) modalities, are capturing increasing attention because they are promising to improve the accuracy of diagnosis. The embedded Gd(3+) ions in UCNPs, however, have an indistinct MRI enhancement owing to the inefficient exchange of magnetic fields with the surrounding water protons. In this study, a novel approach is developed to improve the MR imaging sensitivity of Gd(3+)-ion-doped UCNPs. Bovine serum albumin (BSA) bundled with DTPA-Gd(3+) (DTPA(Gd)) is synthesized both as the MR imaging sensitivity synergist and phase-transfer ligand for the surface engineering of UCNPs. The external Gd(3+) ion attachment strategy is found to significant improve the MR imaging sensitivity of Gd(3+)-ion-doped UCNPs. The relaxivity analysis shows that UCNPs@BSADTPA(Gd) exhibit higher relaxivity values than do UCNPs@BSA without DTPA(Gd) moieties. Another relaxivity study discloses a striking message that the relaxivity value does not always reflect the realistic MRI enhancement capability. The high concentration of Gd(3+)-ion-containing UCNPs with further surface-engineered BSADTPA(Gd) (denoted as UCNPs-H@BSADTPA(Gd)) exhibits a more pronounced MRI enhancement capability compared to the other two counterparts [UCNPs-N@BSADTPA(Gd) and UCNPs-L@BSADTPA(Gd) (-N and -L are denoted as zero and low concentrations of Gd(3+) ion doping, respectively)], even though it holds the lowest r1 of 1.56 s(-1) per mmol L(-1) of Gd(3+). The physicochemical properties of UCNPs are essentially maintained after BSADTPA(Gd) surface decoration with good colloidal stability, in addition to improving the MR imaging sensitivity. In vivo T1-weighted MRI shows potent tumor-enhanced MRI with UCNPs-H@BSADTPA(Gd). An in vivo biodistribution study indicates that it is gradually excreted from the body via hepatobiliary and renal processing with no obvious toxicity. It could therefore be concluded, with improved MR imaging sensitivity by an internal and external incorporation of Gd(3+) strategy, that UCNPs-H@BSADTPA(Gd) presents great potential as an alternative in tumor-targeted MR imaging. PMID:26740341

  8. Kaempferol-3-O-rhamnoside isolated from the leaves of Schima wallichii Korth. inhibits MCF-7 breast cancer cell proliferation through activation of the caspase cascade pathway

    PubMed Central

    DIANTINI, AJENG; SUBARNAS, ANAS; LESTARI, KERI; HALIMAH, ELI; SUSILAWATI, YASMIWAR; SUPRIYATNA; JULAEHA, EUIS; ACHMAD, TRI H.; SURADJI, EKA W.; YAMAZAKI, CHIHO; KOBAYASHI, KENJI; KOYAMA, HIROSHI; ABDULAH, RIZKY

    2012-01-01

    Plants consumed by non-human primates represent potential drug sources for human disease management. In this study, we isolated kaempferol-3-O-rhamnoside as an active compound from the leaves of Schima wallichii Korth., a plant commonly consumed by non-human primates. Its anti-cancer activities, including its ability to induce apoptotic mechanisms, were investigated in MCF-7 breast cancer cells. Results showed that in MCF-7 cells, kaempferol-3-O-rhamnoside inhibits cell proliferation in a dose-dependent manner and promotes apoptosis via the activation of the caspase signaling cascade, which includes caspase-9, caspase-3 and PARP. Our results provide a basis for further exploration of kaempferol-3-O-rhamnoside as an active compound for potential anti-cancer therapeutics. PMID:22783393

  9. Nanoparticles

    NASA Astrophysics Data System (ADS)

    Keshavarz, Mohsen K.; Vasilevskiy, Dimitri; Masut, Remo A.; Turenne, Sylvain

    2014-06-01

    Nanostructured bulk materials are regarded as a means of enhancing the performance of thermoelectric (TE) materials and devices. Powder metallurgy has the distinct advantage over conventional synthesis that it can start directly from nanosized particles. However, further processing, for example extrusion, usually requires elevated temperatures, which lead to grain growth. We have found that introduction of semiconductor nanoparticles of molybdenum disulfide (MoS2), a well-known solid lubricant, suppresses grain growth in bismuth telluride-based alloys, thus improving the extrusion process. Scanning electron microscope images show that adding MoS2 particles at concentrations of 0.2, 0.4, and 0.8 wt% to p-type (Bi0.2Sb0.8)2Te3, under otherwise identical extrusion conditions, reduces average grain size by a factor of four. Scherer's formula applied to x-ray diffraction data indicates that average crystallite sizes (17 nm) of powders are not significantly different from those of alloys extruded with MoS2 (18 nm), which is in stark contrast with those for conventional alloy (Bi0.2Sb0.8)2Te3 extruded under the same conditions (80 nm). Harman measurements of TE properties reveal a decrease of the thermal conductivity accompanied by reduction of the room-temperature figure of merit ( ZT) from 0.9 to 0.7, because of a lower power factor. Above 370 K, however, the performance of alloys containing MoS2 surpasses that of (Bi0.2Sb0.8)2Te3, with reduction of the thermal conductivity which is more significant at temperatures above the cross point of the ZT values.

  10. Kaempferol in red and pinto bean seed (Phaseolus vulgaris L.) coats inhibits iron bioavailability using an in vitro digestion/human Caco-2 cell model.

    PubMed

    Hu, Ying; Cheng, Zhiqiang; Heller, Larry I; Krasnoff, Stuart B; Glahn, Raymond P; Welch, Ross M

    2006-11-29

    Four different colored beans (white, red, pinto, and black beans) were investigated for factors affecting iron bioavailability using an in vitro digestion/human Caco-2 cell model. Iron bioavailability from whole beans, dehulled beans, and their hulls was determined. The results show that white beans contained higher levels of bioavailable iron compared to red, pinto, and black beans. These differences in bioavailable iron were not due to bean-iron and bean-phytate concentrations. Flavonoids in the colored bean hulls were found to be contributing to the low bioavailability of iron in the non-white colored beans. White bean hulls contained no detectable flavonoids but did contain an unknown factor that may promote iron bioavailability. The flavonoids, kaempferol and astragalin (kaempferol-3-O-glucoside), were identified in red and pinto bean hulls via HPLC and MS. Some unidentified anthocyanins were also detected in the black bean hulls but not in the other colored bean hulls. Kaempferol, but not astragalin, was shown to inhibit iron bioavailability. Treating in vitro bean digests with 40, 100, 200, 300, 400, 500, and 1000 microM kaempferol significantly inhibited iron bioavailability (e.g., 15.5% at 40 microM and 62.8% at 1000 microM) in a concentration-dependent fashion. Thus, seed coat kaempferol was identified as a potent inhibitory factor affecting iron bioavailability in the red and pinto beans studied. Results comparing the inhibitory effects of kaempferol, quercitrin, and astragalin on iron bioavailability suggest that the 3',4'-dihydroxy group on the B-ring in flavonoids contributes to the lower iron bioavailability. PMID:17117818

  11. A general chelate-assisted co-assembly to metallic nanoparticles-incorporated ordered mesoporous carbon catalysts for Fischer-Tropsch synthesis.

    PubMed

    Sun, Zhenkun; Sun, Bo; Qiao, Minghua; Wei, Jing; Yue, Qin; Wang, Chun; Deng, Yonghui; Kaliaguine, Serge; Zhao, Dongyuan

    2012-10-24

    The organization of different nano objects with tunable sizes, morphologies, and functions into integrated nanostructures is critical to the development of novel nanosystems that display high performances in sensing, catalysis, and so on. Herein, using acetylacetone as a chelating agent, phenolic resol as a carbon source, metal nitrates as metal sources, and amphiphilic copolymers as a template, we demonstrate a chelate-assisted multicomponent coassembly method to synthesize ordered mesoporous carbon with uniform metal-containing nanoparticles. The obtained nanocomposites have a 2-D hexagonally arranged pore structure, uniform pore size (~4.0 nm), high surface area (~500 m(2)/g), moderate pore volume (~0.30 cm(3)/g), uniform and highly dispersed Fe(2)O(3) nanoparticles, and constant Fe(2)O(3) contents around 10 wt %. By adjusting acetylacetone amount, the size of Fe(2)O(3) nanoparticles is readily tunable from 8.3 to 22.1 nm. More importantly, it is found that the metal-containing nanoparticles are partially embedded in the carbon framework with the remaining part exposed in the mesopore channels. This unique semiexposure structure not only provides an excellent confinement effect and exposed surface for catalysis but also helps to tightly trap the nanoparticles and prevent aggregating during catalysis. Fischer-Tropsch synthesis results show that as the size of iron nanoparticles decreases, the mesoporous Fe-carbon nanocomposites exhibit significantly improved catalytic performances with C(5+) selectivity up to 68%, much better than any reported promoter-free Fe-based catalysts due to the unique semiexposure morphology of metal-containing nanoparticles confined in the mesoporous carbon matrix. PMID:23020275

  12. Kaempferol induces apoptosis in human HCT116 colon cancer cells via the Ataxia-Telangiectasia Mutated-p53 pathway with the involvement of p53 Upregulated Modulator of Apoptosis.

    PubMed

    Li, Wei; Du, Bingna; Wang, Tianyi; Wang, Siling; Zhang, Jinghai

    2009-01-27

    Dietary flavonols have been found to possess preventive and therapeutic potential against several kinds of cancers. This study is conducted to investigate the anti-proliferation effects of kaempferol, a major component of food flavonols, against colon cancer cells. In the human HCT116 colon cancer cell line, kaempferol induced p53-dependent growth inhibition and apoptosis. Furthermore, kaempferol was found to induce cytochrome c release from mitochondria and activate caspase-3 cleavage. The Bcl-2 family proteins including PUMA were involved in this process. Kaempferol also induced ATM and H2AX phosphorylation in HCT116 cells, inhibition of ATM by a chemical inhibitor resulted in abrogation of the downstream apoptotic cascades. These findings suggest kaempferol could be a potent candidate for colorectal cancer management. PMID:19028473

  13. Effect of incorporation of different modified Al2O3 nanoparticles on holographic characteristics of PVA/AA photopolymer composites.

    PubMed

    Li, Yunxi; Wang, Chunhui; Li, Hailong; Wang, Xiaoyi; Han, Junhe; Huang, Mingju

    2015-11-20

    Al2O3 nanoparticles modified with different chemical reagents, prepared by using three chemical dispersants [high definition (HD), sodium dodecyl benzene sulfonate, and cetyl trimethyl ammonium chloride], were doped into photopolymer films in a polyvinyl alcohol/acrylamide (PVA/AA) system, respectively. A 647 nm Ar-Kr laser was used to expose and study the holographic properties of the samples. The research shows that doping Al2O3 nanoparticles into PVA/AA photopolymer film leads to different levels of improvement of the holographic characteristics. The diffraction efficiency of the sample can be raised to 93.8%, the maximum refractive index modulation increased to 2.28×10-3, the shrinkage can be depressed to 0.8%, and the Bragg mismatch is 0.04°, while the concentration of 10 nm Al2O3 nanoparticles modified by HD dispersant is 1.02×10-3  mol·L-1. PMID:26836540

  14. In-situ and ex-situ characterization of TiO2 and Au nanoparticle incorporated TiO2 thin films for optical gas sensing at extreme temperatures

    NASA Astrophysics Data System (ADS)

    Ohodnicki, Paul R.; Wang, Congjun; Natesakhawat, Sittichai; Baltrus, John P.; Brown, Thomas D.

    2012-03-01

    Sensor technologies that can operate under extreme conditions including high temperatures, high pressures, highly reducing and oxidizing environments, and corrosive gases are needed for process monitoring and control in advanced fossil energy applications. Sensor technologies based on optical waveguide-based techniques are highly attractive for passive, embedded, and remote sensing. A critical enabling technology for optical waveguide sensors is the development of advanced optical thin film coatings which have a desired set of optical properties that change in a rapid, selective, and sensitive manner to a particular quantity of interest. TiO2 and Au nanoparticle incorporated TiO2 nanocomposite thin films were prepared through sol-gel deposition techniques and their respective optical responses to a 4% H2/N2 mixture were investigated in the visible / near-IR range of 400-1000 nm. A tendency for Au nanoparticles to occupy special sites on the TiO2 microstructure, such as grain boundaries, twin boundaries, and triple points is rationalized in terms of basic surface energy arguments. The Au / TiO2 nanocomposite films showed a useful optical response due to a reversible, rapid, and repeatable shift in the localized surface plasma resonance peak of Au nanoparticles at a temperature of 650 C and 850 C. In contrast, high temperature exposure of TiO2 films to reducing gases at 850 C resulted in the growth of abnormally large grains or "hillocks" that protruded from the sample surface and resulted in light scattering and an irreversible decrease in transmission at short wavelengths. The origin of the observed optical response of Au / TiO2 nanocomposite films is discussed in the context of work by prior investigators in the Au / yttria-stabilized Zirconia (YSZ) system and needs for future research in this area is highlighted.

  15. Screening of Korean Natural Products for Anti-Adipogenesis Properties and Isolation of Kaempferol-3-O-rutinoside as a Potent Anti-Adipogenetic Compound from Solidago virgaurea.

    PubMed

    Jang, Young Soo; Wang, Zhiqiang; Lee, Jeong-Min; Lee, Jae-Young; Lim, Soon Sung

    2016-01-01

    In this study, the anti-adipogenetic activity of 300 plant extracts was investigated using an Oil Red O staining assay in a 3T3-L1 cell line. Our results indicate that three plants, including the stem and leaf of Physalis angulata, the whole grass of Solidago virgaurea, and the root of Dioscorea nipponica, produced over 90% inhibition of adipogenesis. Kaempferol-3-O-rutinoside, which demonstrated a 48.2% inhibitory effect on adipogenesis without cytotoxicity, was isolated from the butanol layer of a water extract of S. virgaurea guided by the anti-adipogenesis assay in 3T3-L1. PPAR-γ and C/EBPα expression levels were determined using western blot, and our results indicate that kaempferol-3-O-rutinoside has a strong anti-adipogenic effect in 3T3-L1 cells through the suppression of increases in PPAR-γ and C/EBPα expression. PMID:26901177

  16. Synthesis, Characterization, DNA Interaction, and Antitumor Activities of La (III) Complex with Schiff Base Ligand Derived from Kaempferol and Diethylenetriamine

    PubMed Central

    Wang, Qin; Huang, Yu; Zhang, Jin-Sheng; Yang, Xin-Bin

    2014-01-01

    A novel La (III) complex, [LaL(H2O)3]NO3·3H2O, with Schiff base ligand L derived from kaempferol and diethylenetriamine, has been synthesized and characterized by elemental analysis, IR, UV-visible, 1H NMR, thermogravimetric analysis, and molar conductance measurements. The fluorescence spectra, circular dichroism spectra, and viscosity measurements and gel electrophoresis experiments indicated that the ligand L and La (III) complex could bind to CT-DNA presumably via intercalative mode and the La (III) complex showed a stronger ability to bind and cleave DNA than the ligand L alone. The binding constants (Kb) were evaluated from fluorescence data and the values ranged from 0.454 to 0.659 × 105 L mol−1 and 1.71 to 17.3 × 105 L mol−1 for the ligand L and La (III) complex, respectively, in the temperature range of 298–310 K. It was also found that the fluorescence quenching mechanism of EB-DNA by ligand L and La (III) complex was a static quenching process. In comparison to free ligand L, La (III) complex exhibited enhanced cytotoxic activities against tested tumor cell lines HL-60 and HepG-2, which may correlate with the enhanced DNA binding and cleaving abilities of the La (III) complex. PMID:25371657

  17. The Dietary Flavonoid Kaempferol Mediates Anti-Inflammatory Responses via the Src, Syk, IRAK1, and IRAK4 Molecular Targets

    PubMed Central

    Kim, Shi Hyoung; Park, Jae Gwang; Lee, Jongsung; Yang, Woo Seok; Park, Gye Won; Kim, Han Gyung; Baek, Kwang-Soo; Hossen, Muhammad Jahangir; Lee, Mi-nam; Kim, Jong-Hoon

    2015-01-01

    Even though a lot of reports have suggested the anti-inflammatory activity of kaempferol (KF) in macrophages, little is known about its exact anti-inflammatory mode of action and its immunopharmacological target molecules. In this study, we explored anti-inflammatory activity of KF in LPS-treated macrophages. In particular, molecular targets for KF action were identified by using biochemical and molecular biological analyses. KF suppressed the release of nitric oxide (NO) and prostaglandin E2 (PGE2), downregulated the cellular adhesion of U937 cells to fibronectin (FN), neutralized the generation of radicals, and diminished mRNA expression levels of inflammatory genes encoding inducible NO synthase (iNOS), TNF-?, and cyclooxygenase- (COX-) 2 in lipopolysaccharide- (LPS-) and sodium nitroprusside- (SNP-) treated RAW264.7 cells and peritoneal macrophages. KF reduced NF-?B (p65 and p50) and AP-1 (c-Jun and c-Fos) levels in the nucleus and their transcriptional activity. Interestingly, it was found that Src, Syk, IRAK1, and IRAK4 responsible for NF-?B and AP-1 activation were identified as the direct molecular targets of KF by kinase enzyme assays and by measuring their phosphorylation patterns. KF was revealed to have in vitro and in vivo anti-inflammatory activity by the direct suppression of Src, Syk, IRAK1, and IRAK4, involved in the activation of NF-?B and AP-1. PMID:25922567

  18. The application of continuous wavelet transform and least squares support vector machine for the simultaneous quantitative spectrophotometric determination of Myricetin, Kaempferol and Quercetin as flavonoids in pharmaceutical plants.

    PubMed

    Sohrabi, Mahmoud Reza; Darabi, Golnaz

    2016-01-01

    Flavonoids are ?-benzopyrone derivatives, which are highly regarded in these researchers for their antioxidant property. In this study, two new signals processing methods been coupled with UV spectroscopy for spectral resolution and simultaneous quantitative determination of Myricetin, Kaempferol and Quercetin as flavonoids in Laurel, St. John's Wort and Green Tea without the need for any previous separation procedure. The developed methods are continuous wavelet transform (CWT) and least squares support vector machine (LS-SVM) methods integrated with UV spectroscopy individually. Different wavelet families were tested by CWT method and finally the Daubechies wavelet family (Db4) for Myricetin and the Gaussian wavelet families for Kaempferol (Gaus3) and Quercetin (Gaus7) were selected and applied for simultaneous analysis under the optimal conditions. The LS-SVM was applied to build the flavonoids prediction model based on absorption spectra. The root mean square errors for prediction (RMSEP) of Myricetin, Kaempferol and Quercetin were 0.0552, 0.0275 and 0.0374, respectively. The developed methods were validated by the analysis of the various synthetic mixtures associated with a well- known flavonoid contents. Mean recovery values of Myricetin, Kaempferol and Quercetin, in CWT method were 100.123, 100.253, 100.439 and in LS-SVM method were 99.94, 99.81 and 99.682, respectively. The results achieved by analyzing the real samples from the CWT and LS-SVM methods were compared to the HPLC reference method and the results were very close to the reference method. Meanwhile, the obtained results of the one-way ANOVA (analysis of variance) test revealed that there was no significant difference between the suggested methods. PMID:26241831

  19. The application of continuous wavelet transform and least squares support vector machine for the simultaneous quantitative spectrophotometric determination of Myricetin, Kaempferol and Quercetin as flavonoids in pharmaceutical plants

    NASA Astrophysics Data System (ADS)

    Sohrabi, Mahmoud Reza; Darabi, Golnaz

    2016-01-01

    Flavonoids are γ-benzopyrone derivatives, which are highly regarded in these researchers for their antioxidant property. In this study, two new signals processing methods been coupled with UV spectroscopy for spectral resolution and simultaneous quantitative determination of Myricetin, Kaempferol and Quercetin as flavonoids in Laurel, St. John's Wort and Green Tea without the need for any previous separation procedure. The developed methods are continuous wavelet transform (CWT) and least squares support vector machine (LS-SVM) methods integrated with UV spectroscopy individually. Different wavelet families were tested by CWT method and finally the Daubechies wavelet family (Db4) for Myricetin and the Gaussian wavelet families for Kaempferol (Gaus3) and Quercetin (Gaus7) were selected and applied for simultaneous analysis under the optimal conditions. The LS-SVM was applied to build the flavonoids prediction model based on absorption spectra. The root mean square errors for prediction (RMSEP) of Myricetin, Kaempferol and Quercetin were 0.0552, 0.0275 and 0.0374, respectively. The developed methods were validated by the analysis of the various synthetic mixtures associated with a well- known flavonoid contents. Mean recovery values of Myricetin, Kaempferol and Quercetin, in CWT method were 100.123, 100.253, 100.439 and in LS-SVM method were 99.94, 99.81 and 99.682, respectively. The results achieved by analyzing the real samples from the CWT and LS-SVM methods were compared to the HPLC reference method and the results were very close to the reference method. Meanwhile, the obtained results of the one-way ANOVA (analysis of variance) test revealed that there was no significant difference between the suggested methods.

  20. Soy Leaf Extract Containing Kaempferol Glycosides and Pheophorbides Improves Glucose Homeostasis by Enhancing Pancreatic β-Cell Function and Suppressing Hepatic Lipid Accumulation in db/db Mice.

    PubMed

    Li, Hua; Ji, Hyeon-Seon; Kang, Ji-Hyun; Shin, Dong-Ha; Park, Ho-Yong; Choi, Myung-Sook; Lee, Chul-Ho; Lee, In-Kyung; Yun, Bong-Sik; Jeong, Tae-Sook

    2015-08-19

    This study investigated the molecular mechanisms underlying the antidiabetic effect of an ethanol extract of soy leaves (ESL) in db/db mice. Control groups (db/+ and db/db) were fed a normal diet (ND), whereas the db/db-ESL group was fed ND with 1% ESL for 8 weeks. Dietary ESL improved glucose tolerance and lowered plasma glucose, glycated hemoglobin, HOMA-IR, and triglyceride levels. The pancreatic insulin content of the db/db-ESL group was significantly greater than that of the db/db group. ESL supplementation altered pancreatic IRS1, IRS2, Pdx1, Ngn3, Pax4, Ins1, Ins2, and FoxO1 expression. Furthermore, ESL suppressed lipid accumulation and increased glucokinase activity in the liver. ESL primarily contained kaempferol glycosides and pheophorbides. Kaempferol, an aglycone of kaempferol glycosides, improved β-cell proliferation through IRS2-related FoxO1 signaling, whereas pheophorbide a, a product of chlorophyll breakdown, improved insulin secretion and β-cell proliferation through IRS1-related signaling with protein kinase A in MIN6 cells. ESL effectively regulates glucose homeostasis by enhancing IRS-mediated β-cell insulin signaling and suppressing SREBP-1-mediated hepatic lipid accumulation in db/db mice. PMID:26211813

  1. Protective Effects of Kaempferol against Myocardial Ischemia/Reperfusion Injury in Isolated Rat Heart via Antioxidant Activity and Inhibition of Glycogen Synthase Kinase-3β

    PubMed Central

    Zhou, Mingjie; Ren, Huanhuan; Han, Jichun; Wang, Wenjuan; Zheng, Qiusheng; Wang, Dong

    2015-01-01

    Objective. This study aimed to evaluate the protective effect of kaempferol against myocardial ischemia/reperfusion (I/R) injury in rats. Method. Left ventricular developed pressure (LVDP) and its maximum up/down rate (±dp/dtmax) were recorded as myocardial function. Infarct size was detected with 2,3,5-triphenyltetrazolium chloride staining. Cardiomyocyte apoptosis was determined using terminal deoxynucleotidyl nick-end labeling (TUNEL). The levels of creatine kinase (CK), lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione/glutathione disulfide (GSH/GSSG) ratio, and tumor necrosis factor-alpha (TNF-α) were determined using enzyme linked immunosorbent assay (ELISA). Moreover, total glycogen synthase kinase-3β (GSK-3β), phospho-GSK-3β (P-GSK-3β), precaspase-3, cleaved caspase-3, and cytoplasm cytochrome C were assayed using Western blot analysis. Results. Pretreatment with kaempferol significantly improved the recovery of LVDP and ±dp/dtmax, as well as increased the levels of SOD and P-GSK-3β and GSH/GSSG ratio. However, the pretreatment reduced myocardial infarct size and TUNEL-positive cell rate, as well as decreased the levels of cleaved caspase-3, cytoplasm cytochrome C, CK, LDH, MDA, and TNF-α. Conclusion. These results suggested that kaempferol provides cardioprotection via antioxidant activity and inhibition of GSK-3β activity in rats with I/R. PMID:26265983

  2. Kaempferol Suppresses Transforming Growth Factor-β1–Induced Epithelial-to-Mesenchymal Transition and Migration of A549 Lung Cancer Cells by Inhibiting Akt1-Mediated Phosphorylation of Smad3 at Threonine-1791

    PubMed Central

    Jo, Eunji; Park, Seong Ji; Choi, Yu Sun; Jeon, Woo-Kwang; Kim, Byung-Chul

    2015-01-01

    Kaempferol, a natural dietary flavonoid, is well known to possess chemopreventive and therapeutic anticancer efficacy; however, its antimetastatic effects have not been mechanistically studied so far in any cancer model. This study was aimed to investigate the inhibitory effect and accompanying mechanisms of kaempferol on epithelial-to-mesenchymal transition (EMT) and cell migration induced by transforming growth factor-β1 (TGF-β1). In human A549 non–small lung cancer cells, kaempferol strongly blocked the enhancement of cell migration by TGF-β1–induced EMT through recovering the loss of E-cadherin and suppressing the induction of mesenchymal markers as well as the upregulation of TGF-β1–mediated matrix metalloproteinase-2 activity. Interestingly, kaempferol reversed TGF-β1–mediated Snail induction and E-cadherin repression by weakening Smad3 binding to the Snail promoter without affecting its C-terminus phosphorylation, complex formation with Smad4, and nuclear translocation under TGF-β1 stimulation. Mechanism study revealed that the phosphorylation of Smad3 linker region induced by TGF-β1 was required for the induction of EMT and cell migration, and selective downregulation of the phosphorylation of Smad3 at Thr179 residue (not Ser204, Ser208, and Ser213) in the linker region was responsible for the inhibition by kaempferol of TGF-β1–induced EMT and cell migration. Furthermore, Akt1 was required for TGF-β1–mediated induction of EMT and cell migration and directly phosphorylated Smad3 at Thr179, and kaempferol completely abolished TGF-β1–induced Akt1 phosphorylation. In summary, kaempferol blocks TGF-β1–induced EMT and migration of lung cancer cells by inhibiting Akt1-mediated phosphorylation of Smad3 at Thr179 residue, providing the first evidence of a molecular mechanism for the anticancer effect of kaempferol. PMID:26297431

  3. Kaempferol Suppresses Transforming Growth Factor-β1-Induced Epithelial-to-Mesenchymal Transition and Migration of A549 Lung Cancer Cells by Inhibiting Akt1-Mediated Phosphorylation of Smad3 at Threonine-179.

    PubMed

    Jo, Eunji; Park, Seong Ji; Choi, Yu Sun; Jeon, Woo-Kwang; Kim, Byung-Chul

    2015-07-01

    Kaempferol, a natural dietary flavonoid, is well known to possess chemopreventive and therapeutic anticancer efficacy; however, its antimetastatic effects have not been mechanistically studied so far in any cancer model. This study was aimed to investigate the inhibitory effect and accompanying mechanisms of kaempferol on epithelial-to-mesenchymal transition (EMT) and cell migration induced by transforming growth factor-β1 (TGF-β1). In human A549 non-small lung cancer cells, kaempferol strongly blocked the enhancement of cell migration by TGF-β1-induced EMT through recovering the loss of E-cadherin and suppressing the induction of mesenchymal markers as well as the upregulation of TGF-β1-mediated matrix metalloproteinase-2 activity. Interestingly, kaempferol reversed TGF-β1-mediated Snail induction and E-cadherin repression by weakening Smad3 binding to the Snail promoter without affecting its C-terminus phosphorylation, complex formation with Smad4, and nuclear translocation under TGF-β1 stimulation. Mechanism study revealed that the phosphorylation of Smad3 linker region induced by TGF-β1 was required for the induction of EMT and cell migration, and selective downregulation of the phosphorylation of Smad3 at Thr179 residue (not Ser204, Ser208, and Ser213) in the linker region was responsible for the inhibition by kaempferol of TGF-β1-induced EMT and cell migration. Furthermore, Akt1 was required for TGF-β1-mediated induction of EMT and cell migration and directly phosphorylated Smad3 at Thr179, and kaempferol completely abolished TGF-β1-induced Akt1 phosphorylation. In summary, kaempferol blocks TGF-β1-induced EMT and migration of lung cancer cells by inhibiting Akt1-mediated phosphorylation of Smad3 at Thr179 residue, providing the first evidence of a molecular mechanism for the anticancer effect of kaempferol. PMID:26297431

  4. Incorporation effect of nanosized perovskite LaFe₀.₇Co₀.₃O₃ on the electrochemical activity of Pt nanoparticles-multi walled carbon nanotube composite toward methanol oxidation

    SciTech Connect

    Noroozifar, Meissam; Khorasani-Motlagh, Mozhgan; Khaleghian-Moghadam, Roghayeh; Ekrami-Kakhki, Mehri-Saddat; Shahraki, Mohammad

    2013-05-01

    Nanosized perovskite LaFe₀.₇Co₀.₃O₃ (LFCO) is synthesized through conventional co-precipitation method and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. The incorporation effect of the mentioned perovskite to catalytic activity of the PtNPs-MWCNTs-nafion (or -chitosan) catalyst toward methanol oxidation has been studied by cyclic voltammetry. Based on the electrochemical studies, all MWCNTs-PtNPs-nafion (or chitosan) and MWCNTs-PtNPs-LFCO-nafion (or chitosan) catalysts show a considerable activity for methanol oxidation. However, a synergistic effect is observed when LFCO is added to the catalyst by decreasing the poisoning rate of the Pt catalyst. - Graphical abstract: Nanosized perovskite LaFe₀.₇Co₀.₃O₃ is synthesized and characterized. The incorporation effect of the mentioned perovskite to catalytic activity of the PtNPS-MWCNTs-nafion (or -chitosan) catalyst toward methanol oxidation is studied. Highlights: • Nanocrystalline LaFe₀.₇Co₀.₃O₃ (LFCO) is prepared by a new simple co-precipitation method. • Effect of LFCO to catalytic activity of PtNPS for methanol oxidation is studied. • A synergistic effect is observed when LFCO is added to the Pt catalyst. • Oxygen of LFCO could be considered as active oxygen to remove CO intermediates.

  5. Improved performance of CdS/CdSe quantum dots sensitized solar cell by incorporation of ZnO nanoparticles/reduced graphene oxide nanocomposite as photoelectrode

    NASA Astrophysics Data System (ADS)

    Ghoreishi, F. S.; Ahmadi, V.; Samadpour, M.

    2014-12-01

    Here we present novel quantum dot sensitized solar cells (QDSSC) based on ZnO nanoparticles (NPs)/reduced graphene oxide (RGO) nanocomposite photoanodes for better light harvesting and energy conversion. Photoelectrodes are prepared by doctor blading ZnO NPs/GO nanocomposite paste on a fluorine doped tin oxide substrate which are then sintered at 450 C to obtain ZnO NPs/RGO nanocomposites. The partial reduction of GO after thermal reduction, is studied by Fourier transform infrared and Raman spectroscopies. Cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dots are deposited on the films through successive ionic layer adsorption and reaction and chemical bath deposition methods, respectively. The unique properties of ZnO NPs/RGO photoanodes, lead to a significant enhancement in the photovoltaic properties of solar cells in comparison with bare ZnO photoanodes. Current-voltage characteristics of cells are studied and the best results are obtained from ZnO NPs-RGO/CdS/CdSe with photoelectric conversion efficiency of 2.20% which is almost two times higher than cells which are made by pure ZnO NPs as photoanode (1.28%). Electrochemical impedance measurements show that the enhancement can be attributed to the increase of electron transfer rate in the ZnO NPs/RGO nanocomposite photoanode which arises from the ultrahigh electron mobility in graphene (RGO) sheets.

  6. Treatment with kaempferol suppresses breast cancer cell growth caused by estrogen and triclosan in cellular and xenograft breast cancer models.

    PubMed

    Kim, Seung-Hee; Hwang, Kyung-A; Choi, Kyung-Chul

    2016-02-01

    As a phytoestrogen, kaempferol (Kaem) is one of bioflavonoids, which are found in a variety of vegetables including broccoli, tea and tomato. In this study, the antiproliferative effects of Kaem in triclosn (TCS)-induced cell growth were examined in MCF-7 breast cancer cells. TCS promoted the cell viability of MCF-7 cells via estrogen receptor ? (ER?) as did 17?-estradiol (E2), a positive control. On the other hand, Kaem significantly suppressed E2 or TCS-induced cell growth. To elucidate the molecular mechanisms of TCS and Kaem, alterations in the expressions of cell cycle, apoptosis and metastasis-related genes were identified using western blot assay. The treatment of the cells with TCS up-regulated the protein expressions of cyclin D1, cyclin E and cathepsin D, while down-regulated p21 and bax expressions. Kaem reversed TCS-induced gene expressions in an opposite manner. The phosphorylation of IRS-1, AKT, MEK1/2 and ERK was increased by TCS, indicating that TCS induced MCF-7 cell proliferation via nongenomic ER signaling pathway associated with IGF-1R. Kaem presented an antagonistic activity on this signaling by down-regulating the protein expression of pIRS-1, pAkt and pMEK1/2 promoted by E2 or TCS. In an in vivo xenografted mouse model, tumor growth was induced by treatment with E2 or TCS, which was identified in the measurement of tumor volume, hematoxylin and eosin staining, bromodeoxyuridine and immunohistochemistry assay. On the contrary, E2 or TCS-induced breast tumor growth was inhibited by co-treatment with Kaem, which is consistent with in vitro results. Taken together, these results revealed that Kaem has an anticancer effect against procancer activity of E2 or TCS, a xenoestrogen, in breast cancer and may be suggested as a prominent agent to neutralize breast cancer risk caused by TCS. PMID:26878784

  7. Effect of Ginkgo biloba extract on procarcinogen-bioactivating human CYP1 enzymes: Identification of isorhamnetin, kaempferol, and quercetin as potent inhibitors of CYP1B1

    SciTech Connect

    Chang, Thomas K.H. . E-mail: tchang@interchange.ubc.ca; Chen Jie; Yeung, Eugene Y.H.

    2006-05-15

    In the present study, we investigated the effect of Ginkgo biloba extracts and some of its individual constituents on the catalytic activity of human cytochrome P450 enzymes CYP1B1, CYP1A1, and CYP1A2. G. biloba extract of known abundance of terpene trilactones and flavonol glycosides inhibited 7-ethoxyresorufin O-dealkylation catalyzed by human recombinant CYP1B1, CYP1A1, and CYP1A2, and human liver microsomes, with apparent K {sub i} values of 2 {+-} 0.3, 5 {+-} 0.5, 16 {+-} 1.4, and 39 {+-} 1.2 {mu}g/ml (mean {+-} SE), respectively. In each case, the mode of inhibition was of the mixed type. Bilobalide, ginkgolides A, B, C, and J, quercetin 3-O-rutinoside, kaempferol 3-O-rutinoside, and isorhamentin 3-O-rutinoside were not responsible for the inhibition of CYP1 enzymes by G. biloba extract, as determined by experiments with these individual chemicals at the levels present in the extract. In contrast, the aglycones of quercetin, kaempferol, and isorhamentin inhibited CYP1B1, CYP1A1, and CYP1A2. Among the three flavonol aglycones, isorhamentin was the most potent in inhibiting CYP1B1 (apparent K {sub i} = 3 {+-} 0.1 nM), whereas quercetin was the least potent in inhibiting CYP1A2 (apparent K {sub i} 418 {+-} 50 nM). The mode of inhibition was competitive, noncompetitive, or mixed, depending on the enzyme and the flavonol. G. biloba extract also reduced benzo[a]pyrene hydroxylation, and the effect was greater with CYP1B1 than with CYP1A1 as the catalyst. Overall, our novel findings indicate that G. biloba extract and the flavonol aglycones isorhamnetin, kaempferol, and quercetin preferentially inhibit the in vitro catalytic activity of human CYP1B1.

  8. The anti-obesity and anti-diabetic effects of kaempferol glycosides from unripe soybean leaves in high-fat-diet mice.

    PubMed

    Zang, Yanqing; Zhang, Liping; Igarashi, Kiharu; Yu, Changqing

    2015-03-01

    The present study investigated the anti-obesity and anti-diabetic effects of kaempferol glycoside (KG) fractions which were composed of four kaempferol glycosides and purified from unripe Jindai-soybean (Edamame) leaves in C57BL/6J mice. High fat-fed mice treated with 0.15% dietary KG for 92 days had reduced body weight, adipose tissue and TG levels compared to the high fat-fed control group. KG-treatment also decreased fasting blood glucose, serum HbA1c (hemoglobin A(1c)) levels and improved insulin resistance. Gene expression analysis of the liver showed that KG decreased peroxisome proliferator-activated receptor (PPAR-γ) and sterol regulatory element-binding protein (SREBP-1c) expression. These results suggest that KG reduced the accumulation of adipose tissue, improving hyperlipidemia as well as diabetes in obese mice by increasing lipid metabolism through the downregulation of PPAR-γ and SREBP-1c. Thus, KG may have an anti-obesity and anti-diabetic potential. PMID:25599885

  9. Silver Nanoparticles in Dental Biomaterials

    PubMed Central

    Corrêa, Juliana Mattos; Mori, Matsuyoshi; Sanches, Heloísa Lajas; da Cruz, Adriana Dibo; Poiate, Isis Andréa Venturini Pola

    2015-01-01

    Silver has been used in medicine for centuries because of its antimicrobial properties. More recently, silver nanoparticles have been synthesized and incorporated into several biomaterials, since their small size provides great antimicrobial effect, at low filler level. Hence, these nanoparticles have been applied in dentistry, in order to prevent or reduce biofilm formation over dental materials surfaces. This review aims to discuss the current progress in this field, highlighting aspects regarding silver nanoparticles incorporation, such as antimicrobial potential, mechanical properties, cytotoxicity, and long-term effectiveness. We also emphasize the need for more studies to determine the optimal concentration of silver nanoparticle and its release over time. PMID:25667594

  10. Antiplasmodial properties of kaempferol-3-O-rhamnoside isolated from the leaves of Schima wallichii against chloroquine-resistant Plasmodium falciparum

    PubMed Central

    BARLIANA, MELISA I.; SURADJI, EKA W.; ABDULAH, RIZKY; DIANTINI, AJENG; HATABU, TOSHIMITSU; NAKAJIMA-SHIMADA, JUNKO; SUBARNAS, ANAS; KOYAMA, HIROSHI

    2014-01-01

    Previous intervention studies have shown that the most effective agents used in the treatment of malaria were isolated from natural sources. Plants consumed by non-human primates serve as potential drug sources for human disease management due to the similarities in anatomy, physiology and disease characteristics. The present study investigated the antiplasmodial properties of the primate-consumed plant, Schima wallichii (S. wallichii) Korth. (family Theaceae), which has already been reported to have several biological activities. The ethanol extract of S. wallichii was fractionated based on polarity using n-hexane, ethyl acetate and water. The antiplasmodial activity was tested in vitro against chloroquine-resistant Plasmodium falciparum (P. falciparum) at 100 μg/ml for 72 h. The major compound of the most active ethyl acetate fraction was subsequently isolated using column chromatography and identified by nuclear magnetic resonance. The characterized compound was also tested against chloroquine-resistant P. falciparum in culture to evaluate its antiplasmodial activity. The ethanol extract of S. wallichii at 100 μg/ml exhibited a significant parasite shrinkage after 24 h of treatment. The ethyl acetate fraction at 100 μg/ml was the most active fraction against chloroquine-resistant P. falciparum. Based on the structural characterization, the major compound isolated from the ethyl acetate fraction was kaempferol-3-O-rhamnoside, which showed promising antiplasmodial activity against chloroquine-resistant P. falciparum with an IC50 of 106 μM after 24 h of treatment. The present study has provided a basis for the further investigation of kaempferol-3-O-rhamnoside as an active compound for potential antimalarial therapeutics. PMID:24944812

  11. Neuroprotective Effect of Kaempferol Glycosides against Brain Injury and Neuroinflammation by Inhibiting the Activation of NF-?B and STAT3 in Transient Focal Stroke

    PubMed Central

    Wang, Liang-Fen; Kuang, Xi; Liu, Ke; Zhang, Hao; Du, Jun-Rong

    2013-01-01

    Background Ischemic brain injury is associated with neuroinflammatory response, which essentially involves glial activation and neutrophil infiltration. Transcription factors nuclear factor-?B (NF-?B) and signal transducer and activator of transcription 3 (STAT3) contribute to ischemic neuroinflammatory processes and secondary brain injury by releasing proinflammatory mediators. Kaempferol-3-O-rutinoside (KRS) and kaempferol-3-O- glucoside (KGS) are primary flavonoids found in Carthamus tinctorius L. Recent studies demonstrated that KRS protected against ischemic brain injury. However, little is known about the underlying mechanisms. Flavonoids have been reported to have antiinflammatory properties. Herein, we explored the effects of KRS and KGS in a transient focal stroke model. Methodology/Principal Findings Rats were subjected to middle cerebral artery occlusion for 2 hours followed by 22 h reperfusion. An equimolar dose of KRS or KGS was administered i.v. at the beginning of reperfusion. The results showed that KRS or KGS significantly attenuated the neurological deficits, brain infarct volume, and neuron and axon injury, reflected by the upregulation of neuronal nuclear antigen-positive neurons and downregulation of amyloid precursor protein immunoreactivity in the ipsilateral ischemic hemisphere. Moreover, KRS and KGS inhibited the expression of OX-42, glial fibrillary acidic protein, phosphorylated STAT3 and NF-?B p65, and the nuclear content of NF-?B p65. Subsequently, these flavonoids inhibited the expression of tumor necrosis factor ?, interleukin 1?, intercellular adhesion molecule 1, matrix metallopeptidase 9, inducible nitric oxide synthase, and myeloperoxidase. Conclusion/Significance Our findings suggest that postischemic treatment with KRS or KGS prevents ischemic brain injury and neuroinflammation by inhibition of STAT3 and NF-?B activation and has the therapeutic potential for the neuroinflammation-related diseases, such as ischemic stroke. PMID:23437066

  12. Kaempferol Activates G2-Checkpoint of the Cell Cycle Resulting in G2-Arrest and Mitochondria-Dependent Apoptosis in Human Acute Leukemia Jurkat T Cells.

    PubMed

    Kim, Ki Yun; Jang, Won Young; Lee, Ji Young; Jun, Do Youn; Ko, Jee Youn; Yun, Young Ho; Kim, Young Ho

    2016-02-28

    The effect of kaempferol (3,5,7,4-tetrahydroxyflavone), a flavonoid compound that was identified in barnyard millet (Echinochloa crus-galli var. frumentacea) grains, on G2-checkpoint and apoptotic pathways was investigated in human acute leukemia Jurkat T cell clones stably transfected with an empty vector (J/Neo) or a Bcl-xL expression vector (J/Bcl-xL). Exposure of J/Neo cells to kaempeferol caused cytotoxicity and activation of the ATM/ATR-Chk1/Chk2 pathway, activating the phosphorylation of p53 (Ser-15), inhibitory phosphorylation of Cdc25C (Ser-216), and inactivation of cyclin-dependent kinase 1 (Cdk1), with resultant G2- arrest of the cell cycle. Under these conditions, apoptotic events, including upregulation of Bak and PUMA levels, Bak activation, mitochondrial membrane potential (Δψm) loss, activation of caspase-9, -8, and -3, anti-poly (ADP-ribose) polymerase (PARP) cleavage, and accumulation of apoptotic sub-G1 cells, were induced without accompanying necrosis. However, these apoptotic events, except for upregulation of Bak and PUMA levels, were completely abrogated in J/Bcl-xL cells overexpressing Bcl-xL, suggesting that the G2-arrest and the Bcl-xL-sensitive mitochondrial apoptotic events were induced, in parallel, as downstream events of the DNA-damage-mediated G2-checkpoint activation. Together these results demonstrate that kaempferol-mediated antitumor activity toward Jurkat T cells was attributable to G2-checkpoint activation, which caused not only G2-arrest of the cell cycle but also activating phosphorylation of p53 (Ser-15) and subsequent induction of mitochondriadependent apoptotic events, including Bak and PUMA upregulation, Bak activation, Δpsim loss, and caspase cascade activation. PMID:26699757

  13. Characterization of a Glucosyltransferase Enzyme Involved in the Formation of Kaempferol and Quercetin Sophorosides in Crocus sativus1[C][W

    PubMed Central

    Trapero, Almudena; Ahrazem, Oussama; Rubio-Moraga, Angela; Jimeno, Maria Luisa; Gómez, Maria Dolores; Gómez-Gómez, Lourdes

    2012-01-01

    UGT707B1 is a new glucosyltransferase isolated from saffron (Crocus sativus) that localizes to the cytoplasm and the nucleus of stigma and tepal cells. UGT707B1 transcripts were detected in the stigma tissue of all the Crocus species analyzed, but expression analysis of UGT707B1 in tepals revealed its absence in certain species. The analysis of the glucosylated flavonoids present in Crocus tepals reveals the presence of two major flavonoid compounds in saffron: kaempferol-3-O-β-d-glucopyranosyl-(1-2)-β-d-glucopyranoside and quercetin-3-O-β-d-glucopyranosyl-(1-2)-β-d-glucopyranoside, both of which were absent from the tepals of those Crocus species that did not express UGT707B1. Transgenic Arabidopsis (Arabidopsis thaliana) plants constitutively expressing UGT707B1 under the control of the cauliflower mosaic virus 35S promoter have been constructed and their phenotype analyzed. The transgenic lines displayed a number of changes that resembled those described previously in lines where flavonoid levels had been altered. The plants showed hyponastic leaves, a reduced number of trichomes, thicker stems, and flowering delay. Levels of flavonoids measured in extracts of the transgenic plants showed changes in the composition of flavonols when compared with wild-type plants. The major differences were observed in the extracts from stems and flowers, with an increase in 3-sophoroside flavonol glucosides. Furthermore, a new compound not detected in ecotype Columbia wild-type plants was detected in all the tissues and identified as kaempferol-3-O-sophoroside-7-O-rhamnoside. These data reveal the involvement of UGT707B1 in the biosynthesis of flavonol-3-O-sophorosides and how significant changes in flavonoid homeostasis can be caused by the overproduction of a flavonoid-conjugating enzyme. PMID:22649274

  14. Magnetic, fluorescent, and thermo-responsive Fe(3)O(4)/rare earth incorporated poly(St-NIPAM) core-shell colloidal nanoparticles in multimodal optical/magnetic resonance imaging probes.

    PubMed

    Zhu, Haie; Tao, Juan; Wang, Wenhao; Zhou, Yingjie; Li, Penghui; Li, Zheng; Yan, Kai; Wu, Shuilin; Yeung, Kelvin W K; Xu, Zushun; Xu, Haibo; Chu, Paul K

    2013-03-01

    Multifunctional colloidal nanoparticles which exhibit fluorescence, superparamagnetism, and thermosensitivity are produced by two step seed emulsifier-free emulsion polymerization in the presence of oleic acid (OA) and sodium undecylenate (NaUA) modified Fe(3)O(4) nanoparticles. In the first step, St and NIPAM polymerize the NaUA on the surface of Fe(3)O(4) nanoparticles to form Fe(3)O(4)/poly(St-NIPAM) nanoparticles which act as seeds for the polymerization of Eu(AA)(3)Phen with the remaining St and NIPAM in the second step to form an outer fluorescent layer. The core-shell composite nanoparticles show reversible dimensional changes in response to external temperature stimuli. Fluorescence spectra acquired from the composites exhibit characteristic emission peaks of Eu(3+) at 594 and 619 nm and vivid red luminescence can be observed by 2-photon confocal scanning laser microscopy (CLSM). In vitro cytotoxicity tests based on the MTT assay demonstrate good cytocompatibility and the composites also possess paramagnetic properties with a maximum saturation magnetization of 6.45 emu/g and high transverse relaxivity rates (r(2)) of 411.78 mM(-1) s(-1). In vivo magnetic resonance imaging (MRI) studies show significant liver and spleen contrast with relative signal intensity reduction of about 86% 10 min after intravenous injection of the composites. These intriguing properties suggest that these nanocarriers have large clinical potential as multimodal optical/MRI probes. PMID:23274069

  15. Liquid metal/metal oxide frameworks with incorporated Ga2O3 for photocatalysis.

    PubMed

    Zhang, Wei; Naidu, Boddu S; Ou, Jian Zhen; O'Mullane, Anthony P; Chrimes, Adam F; Carey, Benjamin J; Wang, Yichao; Tang, Shi-Yang; Sivan, Vijay; Mitchell, Arnan; Bhargava, Suresh K; Kalantar-Zadeh, Kourosh

    2015-01-28

    Solvothermally synthesized Ga2O3 nanoparticles are incorporated into liquid metal/metal oxide (LM/MO) frameworks in order to form enhanced photocatalytic systems. The LM/MO frameworks, both with and without incorporated Ga2O3 nanoparticles, show photocatalytic activity due to a plasmonic effect where performance is related to the loading of Ga2O3 nanoparticles. Optimum photocatalytic efficiency is obtained with 1 wt % incorporation of Ga2O3 nanoparticles. This can be attributed to the sub-bandgap states of LM/MO frameworks, contributing to pseudo-ohmic contacts which reduce the free carrier injection barrier to Ga2O3. PMID:25543876

  16. HPLC Plasma Assay of a Novel Anti-MRSA Compound, Kaempferol-3-O-Alpha-L-(2",3"-di-p-coumaroyl)rhamnoside, from Sycamore Leaves.

    PubMed

    Zhang, Yiguan; Valeriote, Frederick; Swartz, Kenneth; Chen, Ben; Hamann, Mark T; Rodenburg, Douglas L; McChesney, James D; Shaw, Jiajiu

    2015-08-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a serious pathogen that is resistant to current antibiotic therapy. Thus, there is an urgent need for novel antimicrobial agents that can effectively combat these new strains of drug-resistant "superbugs". Recently, fractionation of an extract from Platanus occidentalis (American sycamore) leaves produced an active kaempferol molecule, 3-O-alpha-L-(2",3"-di-p-coumaroyl)rhamnoside (KCR), in four isomeric forms; all four isomers exhibit potent anti-MRSA activity. In order to further the preclinical development of KCR as a new antibiotic class, we developed and validated a simple analytical method for assaying KCR plasma concentration. Because KCR will be developed as a new drug, although comprising four stereoisomers, the analytical method was devised to assay the total amount of all four isomers. In the present work, both a plasma processing procedure and an HPLC method have been developed and validated. Mouse plasma containing KCR was first treated with ethanol and then centrifuged. The supernatant was dried, suspended in ethanol, centrifuged, and the supernatant was injected into an HPLC system comprising a Waters C18, a mobile phase composing methanol, acetonitrile, and trifluoroacetic acid and monitored at 313 nm. The method was validated by parameters including a good linear correlation, a limit of quantification of 0.27 microg/mL, and high accuracy. In summary, this method allows a rapid analysis of KCR in the plasma samples for pharmacokinetics studies. PMID:26434123

  17. Simultaneous Quantification of Syringic Acid and Kaempferol in Extracts of Bergenia Species Using Validated High-Performance Thin-Layer Chromatographic-Densitometric Method.

    PubMed

    Srivastava, Nishi; Srivastava, Amit; Srivastava, Sharad; Rawat, Ajay Kumar Singh; Khan, Abdul Rahman

    2016-03-01

    A rapid, sensitive, selective and robust quantitative densitometric high-performance thin-layer chromatographic method was developed and validated for separation and quantification of syringic acid (SYA) and kaempferol (KML) in the hydrolyzed extracts of Bergenia ciliata and Bergenia stracheyi. The separation was performed on silica gel 60F254 high-performance thin-layer chromatography plates using toluene : ethyl acetate : formic acid (5 : 4: 1, v/v/v) as the mobile phase. The quantification of SYA and KML was carried out using a densitometric reflection/absorption mode at 290 nm. A dense spot of SYA and KML appeared on the developed plate at a retention factor value of 0.61 ± 0.02 and 0.70 ± 0.01. A precise and accurate quantification was performed using linear regression analysis by plotting the peak area vs concentration 100-600 ng/band (correlation coefficient: r = 0.997, regression coefficient: R(2) = 0.996) for SYA and 100-600 ng/band (correlation coefficient: r = 0.995, regression coefficient: R(2) = 0.991) for KML. The developed method was validated in terms of accuracy, recovery and inter- and intraday study as per International Conference on Harmonisation guidelines. The limit of detection and limit of quantification of SYA and KML were determined, respectively, as 91.63, 142.26 and 277.67, 431.09 ng. The statistical data analysis showed that the method is reproducible and selective for the estimation of SYA and KML in extracts of B. ciliata and B. stracheyi. PMID:26543088

  18. Carbon Materials Metal/Metal Oxide Nanoparticle Composite and Battery Anode Composed of the Same

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2006-01-01

    A method of forming a composite material for use as an anode for a lithium-ion battery is disclosed. The steps include selecting a carbon material as a constituent part of the composite, chemically treating the selected carbon material to receive nanoparticles, incorporating nanoparticles into the chemically treated carbon material and removing surface nanoparticles from an outside surface of the carbon material with incorporated nanoparticles. A material making up the nanoparticles alloys with lithium.

  19. Nanoparticles for Imaging: Top or Flop?

    PubMed Central

    Mertens, Marianne E.; Grimm, Jan; Lammers, Twan

    2014-01-01

    Nanoparticles are frequently suggested as diagnostic agents. However, except for iron oxide nanoparticles, diagnostic nanoparticles have been barely incorporated into clinical use so far. This is predominantly due to difficulties in achieving acceptable pharmacokinetic properties and reproducible particle uniformity as well as to concerns about toxicity, biodegradation, and elimination. Reasonable indications for the clinical utilization of nanoparticles should consider their biologic behavior. For example, many nanoparticles are taken up by macrophages and accumulate in macrophage-rich tissues. Thus, they can be used to provide contrast in liver, spleen, lymph nodes, and inflammatory lesions (eg, atherosclerotic plaques). Furthermore, cells can be efficiently labeled with nanoparticles, enabling the localization of implanted (stem) cells and tissue-engineered grafts as well as in vivo migration studies of cells. The potential of using nanoparticles for molecular imaging is compromised because their pharmacokinetic properties are difficult to control. Ideal targets for nanoparticles are localized on the endothelial luminal surface, whereas targeted nanoparticle delivery to extravascular structures is often limited and difficult to separate from an underlying enhanced permeability and retention (EPR) effect. The majority of clinically used nanoparticle-based drug delivery systems are based on the EPR effect, and, for their more personalized use, imaging markers can be incorporated to monitor biodistribution, target site accumulation, drug release, and treatment efficacy. In conclusion, although nanoparticles are not always the right choice for molecular imaging (because smaller or larger molecules might provide more specific information), there are other diagnostic and theranostic applications for which nanoparticles hold substantial clinical potential. PMID:25247562

  20. Nanoparticles for imaging: top or flop?

    PubMed

    Kiessling, Fabian; Mertens, Marianne E; Grimm, Jan; Lammers, Twan

    2014-10-01

    Nanoparticles are frequently suggested as diagnostic agents. However, except for iron oxide nanoparticles, diagnostic nanoparticles have been barely incorporated into clinical use so far. This is predominantly due to difficulties in achieving acceptable pharmacokinetic properties and reproducible particle uniformity as well as to concerns about toxicity, biodegradation, and elimination. Reasonable indications for the clinical utilization of nanoparticles should consider their biologic behavior. For example, many nanoparticles are taken up by macrophages and accumulate in macrophage-rich tissues. Thus, they can be used to provide contrast in liver, spleen, lymph nodes, and inflammatory lesions (eg, atherosclerotic plaques). Furthermore, cells can be efficiently labeled with nanoparticles, enabling the localization of implanted (stem) cells and tissue-engineered grafts as well as in vivo migration studies of cells. The potential of using nanoparticles for molecular imaging is compromised because their pharmacokinetic properties are difficult to control. Ideal targets for nanoparticles are localized on the endothelial luminal surface, whereas targeted nanoparticle delivery to extravascular structures is often limited and difficult to separate from an underlying enhanced permeability and retention (EPR) effect. The majority of clinically used nanoparticle-based drug delivery systems are based on the EPR effect, and, for their more personalized use, imaging markers can be incorporated to monitor biodistribution, target site accumulation, drug release, and treatment efficacy. In conclusion, although nanoparticles are not always the right choice for molecular imaging (because smaller or larger molecules might provide more specific information), there are other diagnostic and theranostic applications for which nanoparticles hold substantial clinical potential. PMID:25247562

  1. Fabrication of latex rubber reinforced with micellar nanoparticle as an interface modifier

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reinforced latex rubbers were fabricated by incorporating small amount of nanoparticles as interface modifier. The rubbers were fabricated in a compression mold at 130°C. The incorporated nanoparticles were prepared from wheat protein (gliadin) and ethyl cyanoacrylate (ECA). These nanoparticles were...

  2. Metal-doped semiconductor nanoparticles and methods of synthesis thereof

    DOEpatents

    Ren, Zhifeng (Newton, MA); Chen, Gang (Carlisle, MA); Poudel, Bed (West Newton, MA); Kumar, Shankar (Newton, MA); Wang, Wenzhong (Beijing, CN); Dresselhaus, Mildred (Arlington, MA)

    2009-09-08

    The present invention generally relates to binary or higher order semiconductor nanoparticles doped with a metallic element, and thermoelectric compositions incorporating such nanoparticles. In one aspect, the present invention provides a thermoelectric composition comprising a plurality of nanoparticles each of which includes an alloy matrix formed of a Group IV element and Group VI element and a metallic dopant distributed within the matrix.

  3. Metal-doped semiconductor nanoparticles and methods of synthesis thereof

    NASA Technical Reports Server (NTRS)

    Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Poudel, Bed (Inventor); Kumar, Shankar (Inventor); Wang, Wenzhong (Inventor); Dresselhaus, Mildred (Inventor)

    2009-01-01

    The present invention generally relates to binary or higher order semiconductor nanoparticles doped with a metallic element, and thermoelectric compositions incorporating such nanoparticles. In one aspect, the present invention provides a thermoelectric composition comprising a plurality of nanoparticles each of which includes an alloy matrix formed of a Group IV element and Group VI element and a metallic dopant distributed within the matrix.

  4. Volume-labeled nanoparticles and methods of preparation

    DOEpatents

    Wang, Wei; Gu, Baohua; Retterer, Scott T; Doktycz, Mitchel J

    2015-04-21

    Compositions comprising nanosized objects (i.e., nanoparticles) in which at least one observable marker, such as a radioisotope or fluorophore, is incorporated within the nanosized object. The nanosized objects include, for example, metal or semi-metal oxide (e.g., silica), quantum dot, noble metal, magnetic metal oxide, organic polymer, metal salt, and core-shell nanoparticles, wherein the label is incorporated within the nanoparticle or selectively in a metal oxide shell of a core-shell nanoparticle. Methods of preparing the volume-labeled nanoparticles are also described.

  5. Hydrogel nanoparticle based immunoassay

    DOEpatents

    Liotta, Lance A; Luchini, Alessandra; Petricoin, Emanuel F; Espina, Virginia

    2015-04-21

    An immunoassay device incorporating porous polymeric capture nanoparticles within either the sample collection vessel or pre-impregnated into a porous substratum within fluid flow path of the analytical device is presented. This incorporation of capture particles within the immunoassay device improves sensitivity while removing the requirement for pre-processing of samples prior to loading the immunoassay device. A preferred embodiment is coreshell bait containing capture nanoparticles which perform three functions in one step, in solution: a) molecular size sieving, b) target analyte sequestration and concentration, and c) protection from degradation. The polymeric matrix of the capture particles may be made of co-polymeric materials having a structural monomer and an affinity monomer, the affinity monomer having properties that attract the analyte to the capture particle. This device is useful for point of care diagnostic assays for biomedical applications and as field deployable assays for environmental, pathogen and chemical or biological threat identification.

  6. Modulation of flavonoid metabolites in Arabidopsis thaliana through overexpression of the MYB75 transcription factor: role of kaempferol-3,7-dirhamnoside in resistance to the specialist insect herbivore Pieris brassicae.

    PubMed

    Onkokesung, Nawaporn; Reichelt, Michael; van Doorn, Arjen; Schuurink, Robert C; van Loon, Joop J A; Dicke, Marcel

    2014-05-01

    Anthocyanins and flavonols are secondary metabolites that can function in plant defence against herbivores. In Arabidopsis thaliana, anthocyanin and flavonol biosynthesis are regulated by MYB transcription factors. Overexpression of MYB75 (oxMYB75) in Arabidopsis results in increasing anthocyanin and flavonol levels which enhances plant resistance to generalist caterpillars. However, how these metabolites affect specialist herbivores has remained unknown. Performance of a specialist aphid (Brevicoryne brassicae) was unaffected after feeding on oxMYB75 plants, whereas a specialist caterpillar (Pieris brassicae) gained significantly higher body mass when feeding on this plant. An increase in anthocyanin and total flavonol glycoside levels correlated negatively with the body mass of caterpillars fed on oxMYB75 plants. However, a significant reduction of kaempferol-3,7-dirhamnoside (KRR) corresponded to an increased susceptibility of oxMYB75 plants to caterpillar feeding. Pieris brassicae caterpillars also grew less on an artificial diet containing KRR or on oxMYB75 plants that were exogenously treated with KRR, supporting KRR's function in direct defence against this specialist caterpillar. The results show that enhancing the activity of the anthocyanin pathway in oxMYB75 plants results in re-channelling of quercetin/kaempferol metabolites which has a negative effect on the accumulation of KRR, a novel defensive metabolite against a specialist caterpillar. PMID:24619996

  7. Modulation of flavonoid metabolites in Arabidopsis thaliana through overexpression of the MYB75 transcription factor: role of kaempferol-3,7-dirhamnoside in resistance to the specialist insect herbivore Pieris brassicae

    PubMed Central

    Dicke, Marcel

    2014-01-01

    Anthocyanins and flavonols are secondary metabolites that can function in plant defence against herbivores. In Arabidopsis thaliana, anthocyanin and flavonol biosynthesis are regulated by MYB transcription factors. Overexpression of MYB75 (oxMYB75) in Arabidopsis results in increasing anthocyanin and flavonol levels which enhances plant resistance to generalist caterpillars. However, how these metabolites affect specialist herbivores has remained unknown. Performance of a specialist aphid (Brevicoryne brassicae) was unaffected after feeding on oxMYB75 plants, whereas a specialist caterpillar (Pieris brassicae) gained significantly higher body mass when feeding on this plant. An increase in anthocyanin and total flavonol glycoside levels correlated negatively with the body mass of caterpillars fed on oxMYB75 plants. However, a significant reduction of kaempferol-3,7-dirhamnoside (KRR) corresponded to an increased susceptibility of oxMYB75 plants to caterpillar feeding. Pieris brassicae caterpillars also grew less on an artificial diet containing KRR or on oxMYB75 plants that were exogenously treated with KRR, supporting KRR’s function in direct defence against this specialist caterpillar. The results show that enhancing the activity of the anthocyanin pathway in oxMYB75 plants results in re-channelling of quercetin/kaempferol metabolites which has a negative effect on the accumulation of KRR, a novel defensive metabolite against a specialist caterpillar. PMID:24619996

  8. A focal adhesion kinase inhibitor 16-hydroxy-cleroda-3,13-dien-16,15-olide incorporated into enteric-coated nanoparticles for controlled anti-glioma drug delivery.

    PubMed

    Thiyagarajan, Varadharajan; Lin, Shi-Xiang; Lee, Chia-Hung; Weng, Ching-Feng

    2016-05-01

    16-Hydroxy-cleroda-3,13-dien-16,15-olide (HCD) which is extracted from a medicinal plant, Polyalthia longifolia, was shown to exhibit anticancer activity through apoptosis and FAK inhibition in our previous study. To improve its solubility and efficacy, a novel HCD delivery system using copper-substituted mesoporous silica nanoparticles (MSNs) was designed as a delivery vehicle, and the outer surfaces of MSNs were further coated with enteric polymers to prevent the drug from leaching in the stomach acid. All the data regarding synthesis and physical characterization, including Zeta potential, FT-IR spectra, N2 adsorption-desorption isotherms (BET), drug loading, powder X-ray diffraction, Thermo gravimetric analysis (TGA), Transmission electron microscopy (TEM), and Scanning electron microscopy (SEM) were well characterized. The non-coated MSN-HCD exposed to acidic pH (1.2) showed a rapid degradation of the drug, whereas the enteric-coated samples presented a sustained release profile in the gastrointestinal pHs. Cell cytotoxicity was further confirmed by the MTT-C6 Glioma cell line, in vitro. When compared with the control and pure HCD, the MSN-HCD revealed a potential anti-proliferation effect via the synergistic effect of the drug and the MSN vehicle. Additionally, this MSN-HCD had the effect of increasing the reactive oxygen species (ROS) levels and altered the Mitochondria membrane potential (MMP) in C6 cell line. The in vivo anti-tumor efficacy of enteric-coated MSN-HCD was evaluated by C6 Glioma bearing xenograft nude mice, and enteric-coated MSN-HCD clearly exhibited the greatest anti-glioma activity, as compared to the pure HCD and the untreated control. In terms of the effective treatment of brain glioma, this study provides conclusive evidence of the successful development of the anti-cancer agent HCD conjugated with enteric-coated MSN as a delivery control mechanism with enhanced dissolution characteristics. PMID:26851441

  9. Boronate affinity nanoparticles for RNA isolation.

    PubMed

    Toprak, Aykut; Görgün, Cansu; Kuru, Cansu İlke; Türkcan, Ceren; Uygun, Murat; Akgöl, Sinan

    2015-05-01

    In this presented paper, boronic acid incorporated poly(HEMA) based nanoparticles were synthesized for RNA adsorption. For this purpose, poly(HEMA) nanoparticles were synthesized by using the surfactant free emulsion polymerization technique. Then, nanoparticles were modified with 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) and functionalized with phenylboronic acid (PBA). Prepared nanoparticles were characterized with SEM, FTIR and zeta-size. Optimum RNA adsorption conditions were investigated with different pHs, temperatures and initial RNA concentrations in order to determine the maximum RNA adsorption onto poly(HEMA)-IMEO-PBA nanoparticles. It was also studied that, synthesized nanoparticles could be used for 5 successive reuses and adsorption capacity of the nanoparticles decreased only about 5% at the end of the 5 cycles. PMID:25746268

  10. Development of molecular indicators to track the effects of nanoparticle toxicity in Arabidopsis thaliana

    EPA Science Inventory

    The emergence of nanotechnology and incorporation of nanoparticles in consumer products necessitates risk assessment from an environmental and health safety standpoint. To date, very few studies have examined nanoparticle effects on terrestrial species, especially plants. Pre...

  11. Improved barrier and mechanical properties of novel hydroxypropyl methylcellulose edible films with chitosan/tripolyphosphate nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chitosan/tripolyphosphate nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films. FT-IR and transmission electron microscopy (TEM) analyses of the nanoparticles, mechanical properties, water vapor permeability, thermal stability, scanning electron microscopy (SEM...

  12. Guide to Self, Incorporated.

    ERIC Educational Resources Information Center

    Christopher, Lochie B.; Harrelson, Orvis A.

    This guide is a description of a course designed to help 11-to-13-year-olds cope with the problems that arise as a result of the physical, emotional, and social changes they are experiencing. The package, called "Self-Incorporated," consists of 15 15-minute television programs, this teacher's guide, and related materials which concentrate on

  13. Multiculturalism Incorporated: Student Perceptions

    ERIC Educational Resources Information Center

    Bruch, Patrick L.; Higbee, Jeanne L.; Siaka, Kwabena

    2007-01-01

    Multicultural education has transformed higher education both in terms of research and in terms of student experiences. Given the complexity of our institutions, the overall effects of these transformations are mixed. Building on the successes and strengths of multicultural education as it is currently incorporated in institutions and programs

  14. Elastic compression of nanoparticles with surface energy

    NASA Astrophysics Data System (ADS)

    Ding, Yue; Niu, Xin-Rui; Wang, Gang-Feng

    2015-12-01

    The compression of elastic nanoparticles by two rigid planes is analyzed in the present paper. Through a finite element approach with the incorporation of surface energy, we calculate the elastic field of nanoparticles and obtain the explicit expressions for contact radius and indent depth with respect to the compressive load. It is found that when the contact radius is comparable with the ratio of surface energy density to elastic modulus, surface effect significantly affects the elastic field and the overall compressive response of nanoparticles. This study provides an effective tool to analyze the elastic deformation of nanoparticles, and is helpful to measure their elastic properties through compression.

  15. Theranostic Nanoparticles

    PubMed Central

    Ehlerding, Emily B.

    2014-01-01

    Theranostic nanoparticles hold the potential to revolutionize future disease management. Since the last decade, there has been a growing interest in the engineering of various kinds of theranostic nanoparticles for simultaneous cancer imaging and therapy in small animals. Efficient targeting of theranostic nanoparticles to the tumor site is critical for both diagnostic and therapeutic purposes. However, difficulties still exist in the engineering of biocompatible theranostic nanoparticles with highly specific in vivo tumor targeting capabilities. Here we will discuss the current status and future perspectives of actively targeted theranostic nanoparticles for tumors, as well as challenges that still exist. PMID:25413134

  16. Engineering nanoparticle-protein associations for protein crystal nucleation and nanoparticle arrangement

    NASA Astrophysics Data System (ADS)

    Benoit, Denise N.

    Engineering the nanoparticle - protein association offers a new way to form protein crystals as well as new approaches for arrangement of nanoparticles. Central to this control is the nanoparticle surface. By conjugating polymers on the surface with controlled molecular weights many properties of the nanoparticle can be changed including its size, stability in buffers and the association of proteins with its surface. Large molecular weight poly(ethylene glycol) (PEG) coatings allow for weak associations between proteins and nanoparticles. These interactions can lead to changes in how proteins crystallize. In particular, they decrease the time to nucleation and expand the range of conditions over which protein crystals form. Interestingly, when PEG chain lengths are too short then protein association is minimized and these effects are not observed. One important feature of protein crystals nucleated with nanoparticles is that the nanoparticles are incorporated into the crystals. What results are nanoparticles placed at well-defined distances in composite protein-nanoparticle crystals. Crystals on the size scale of 10 - 100 micrometers exhibit optical absorbance, fluorescence and super paramagnetic behavior derivative from the incorporated nanomaterials. The arrangement of nanoparticles into three dimensional arrays also gives rise to new and interesting physical and chemical properties, such as fluorescence enhancement and varied magnetic response. In addition, anisotropic nanomaterials aligned throughout the composite crystal have polarization dependent optical properties.

  17. Baroplastic core-shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Woog Ryu, Sang; Gonzalez, Juan; Acar, Metin; Mayes, Anne

    2004-03-01

    A novel class of baroplastic core-shell nanoparticles was designed based on the pressure-induced miscibility between a low Tg component core and a high Tg component shell and obtained by a two-stage miniemulsion polymerization technique. By changing the amount of surfactant and monomer feed ratio, the size and composition of core-shell nanoparticles were controlled and almost homogenous particles with very narrow particle size distribution were obtained in each synthetic step. Trilayerd core-shell nanoparticles, which have an additional inner-core, were also successfully synthesized by sequential addition of monomers. The baroplasticity of these core-shell nanoparticles was demonstrated by compression molding and characterized by SANS, DSC, and TEM. Transparent objects were molded at temperatures as low as 25 oC under 5000 psi pressure, and recycled up to 10 times, from poly(n-butyl acrylate)/polystyrene or poly(2-ethyl hexyl acrylate)/polystyrene systems. The particle size was found to play an important role to determine the optical and mechanical properties of the resulting product. By comparison with bilayered core-shell nanoparticles, improved mechanical properties were observed in trilayered systems due to the enlarged interface region. Finally, blend or hybrid baroplastic core-shell nanoparticles were prepared incorporating other polymer or inorganic nanoparticles.

  18. Antibacterial behavior of polypyrrole: The influence of morphology and additives incorporation.

    PubMed

    da Silva, Fernando A G; Queiroz, Jefferson C; Macedo, Ericleiton R; Fernandes, Antonio W C; Freire, Naiana B; da Costa, Mateus M; de Oliveira, Helinando P

    2016-05-01

    The antibacterial behavior of polypyrrole (PPy) depends on a diversity of structural parameters such as surface area, aggregation level and additives (metal nanoparticles) incorporation. This paper summarizes the influence of different preparation procedures of PPy on action of resulting antibacterial composite against Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. The bactericidal action has been assigned to morphology (size of polypyrrole nanoparticles). The electrostatic interaction established between polymer nanoparticles and bacteria provokes the bacterial cell death and returns advantages in comparison with conventional composites of polypyrrole decorated with metal nanoparticles. PMID:26952429

  19. Engineering biofunctional magnetic nanoparticles for biotechnological applications

    NASA Astrophysics Data System (ADS)

    Moros, Maria; Pelaz, Beatriz; Lpez-Larrubia, Pilar; Garca-Martin, Maria L.; Graz, Valeria; de La Fuente, Jesus M.

    2010-09-01

    Synthesis and characterization of magnetic nanoparticles with excellent size control are showed here. Their functionalization using an amphiphilic polymer is also described. This strategy allows the stabilization of magnetic nanoparticles in aqueous solvents and in addition, the polymer shell serves as a platform to incorporate relevant biomolecules, such as poly(ethylene glycol) and a number of carbohydrates. Nanoparticles functionalized with carbohydrates show the ability to avoid unspecific interactions between proteins present in the working medium and the nanoparticles, so can be used as an alternative to poly(ethylene glycol) molecules. Results confirm these nanoparticles as excellent contrast agents for magnetic resonance imaging. Changes in the spin-spin transversal relaxation times of the surrounding water protons due to nanoparticle aggregation demonstrates the bioactivity of these nanoparticles functionalized with carbohydrates. To finish with, nanoparticle toxicity is evaluated by means of MTT assay. The obtained results clearly indicate that these nanoparticles are excellent candidates for their further application in nanomedicine or nanobiotechnology.Synthesis and characterization of magnetic nanoparticles with excellent size control are showed here. Their functionalization using an amphiphilic polymer is also described. This strategy allows the stabilization of magnetic nanoparticles in aqueous solvents and in addition, the polymer shell serves as a platform to incorporate relevant biomolecules, such as poly(ethylene glycol) and a number of carbohydrates. Nanoparticles functionalized with carbohydrates show the ability to avoid unspecific interactions between proteins present in the working medium and the nanoparticles, so can be used as an alternative to poly(ethylene glycol) molecules. Results confirm these nanoparticles as excellent contrast agents for magnetic resonance imaging. Changes in the spin-spin transversal relaxation times of the surrounding water protons due to nanoparticle aggregation demonstrates the bioactivity of these nanoparticles functionalized with carbohydrates. To finish with, nanoparticle toxicity is evaluated by means of MTT assay. The obtained results clearly indicate that these nanoparticles are excellent candidates for their further application in nanomedicine or nanobiotechnology. Electronic supplementary information (ESI) available: Chemical, physical and magnetic characterization; R2 maps; stability of NPs at different conditions; size of glucose NPs in the presence of Concanavalin A; MTT assays of the samples are shown in figures S1-S10. Table S1 represents the hydrodynamic size of PMAO NPs after being washed with different solvents. See DOI: 10.1039/c0nr00104j

  20. Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Khaydarov, R. R.; Khaydarov, R. A.; Estrin, Y.; Evgrafova, S.; Scheper, T.; Endres, C.; Cho, S. Y.

    The bactericidal effect of silver nanoparticles obtained by a novel electrochemical method on Escherichia coli, Staphylococcus aureus, Aspergillus niger and Penicillium phoeniceum cultures has been studied. The tests conducted have demonstrated that synthesized silver nanoparticles when added to water paints or cotton fabrics show a pronounced antibacterial/antifungal effect. It was shown that smaller silver nanoparticles have a greater antibacterial/antifungal efficacy. The paper also provides a review of scientific literature with regard to recent developments in the field of toxicity of silver nanoparticles and its effect on environment and human health.

  1. DISTRIBUTED AMPLIFIER INCORPORATING FEEDBACK

    DOEpatents

    Bell, P.R. Jr.

    1958-10-21

    An improved distributed amplifier system employing feedback for stabilization is presented. In accordance with the disclosed invention, a signal to be amplified is applled to one end of a suitable terminated grid transmission line. At intervals along the transmission line, the signal is fed to stable, resistance-capacitance coupled amplifiers incorporating feedback loops therein. The output current from each amplifier is passed through an additional tube to minimize the electrostatic capacitance between the tube elements of the last stage of the amplifier, and fed to appropriate points on an output transmission line, similar to the grid line, but terminated at the opposite (input) end. The output taken from the unterminated end of the plate transmission line is proportional to the input voltage impressed upon the grid line.

  2. Investigations of nano-particle toxicity and uptake of Cerium oxide and Titanium dioxide in Arabidopsis thaliana (L.)

    EPA Science Inventory

    The emergence of nanotechnology and incorporation of nanoparticles in consumer products necessitates risk assessment from an environmental and health safety standpoint. To date, very few studies have examined nanoparticle effects on terrestrial species, especially plants. In ...

  3. Intermetallic nanoparticles

    DOEpatents

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

    2015-07-14

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  4. Intermetallic nanoparticles

    DOEpatents

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules L.

    2015-11-20

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  5. DNA templated magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Kinsella, Joseph M.

    Recent discoveries in nanoscience are predicted to potentially revolutionize future technologies in an extensive number of fields. These developments are contingent upon discovering new and often unconventional methods to synthesize and control nanoscale components. Nature provides several examples of working nanotechnology such as the use of programmed self assembly to build and deconstruct complex molecular systems. We have adopted a method to control the one dimensional assembly of magnetic nanoparticles using DNA as a scaffold molecule. With this method we have demonstrated the ability to organize 5 nm particles into chains that stretch up to ˜20 mum in length. One advantage of using DNA compared is the ability of the molecule to interact with other biomolecules. After assembling particles onto DNA we have been able to cleave the molecule into smaller fragments using restriction enzymes. Using ligase enzymes we have re-connected these fragments, coated with either gold or iron oxide, to form long one-dimensional arrangements of the two different types of nanoparticles on a single molecular guide. We have also created a sensitive magnetic field sensor by incorporating magnetic nanoparticle coated DNA strands with microfabricated electrodes. The IV characteristics of the aligned nanoparticles are dependant on the magnitude of an externally applied magnetic field. This transport phenomenon known as tunneling magnetoresistance (TMR) shows room temperature resistance of our devices over 80% for cobalt ferrite coated DNA when a field of 20 kOe is applied. In comparison, studies using two dimensional nanoparticle films of irox oxides xii only exhibit a 35% MR effect. Confinement into one dimension using the DNA guide produces a TMR mechanism which produces significant increases in magnetoresistance. This property can be utilized for applications in magnetic field sensing, data storage, and logic elements.

  6. 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

  7. Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles.

    PubMed

    Hwang, Gi Byoung; Heo, Ki Joon; 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 g/cm2(filter) 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()-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

  8. Properties of Novel Hydroxypropyl Methylcellulose Films Containing Chitosan Nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work, chitosan nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films under different conditions. Mechanical properties, water vapor and oxygen permeability, water solubility and scanning and transmission electron microscopy (SEM and TEM) results were ana...

  9. Nanoparticle-Mediated Gene Delivery

    NASA Astrophysics Data System (ADS)

    Jin, Sha; Leach, John C.; Ye, Kaiming

    Nonviral gene delivery has been gaining considerable attention recently. Although the efficacy of DNA transfection, which is a major concern, is low in nonviral vector-mediated gene transfer compared with viral ones, nonviral vectors are relatively easy to prepare, less immunogenic and oncogenic, and have no potential of virus recombination and no limitation on the size of a transferred gene. The ability to incorporate genetic materials such as plasmid DNA, RNA, and siRNA into functionalized nanoparticles with little toxicity demonstrates a new era in pharmacotherapy for delivering genes selectively to tissues and cells. In this chapter, we highlight the basic concepts and applications of nonviral gene delivery using super paramagnetic iron oxide nanoparticles and functionalized silica nanoparticles. The experimental protocols related to these topics are described in the chapter.

  10. Precision Nanoparticles

    ScienceCinema

    John Hemminger

    2010-01-08

    A revolutionary technology that efficiently produces nanoparticles in uniform and prescribed sizes (1-100 nanometers) using supercritical fluids. INL researcher Robert Fox was joined by Idaho State University researchers Rene Rodriquez and Joshua Pak in d

  11. Precision Nanoparticles

    SciTech Connect

    John Hemminger

    2009-07-21

    A revolutionary technology that efficiently produces nanoparticles in uniform and prescribed sizes (1-100 nanometers) using supercritical fluids. INL researcher Robert Fox was joined by Idaho State University researchers Rene Rodriquez and Joshua Pak in d

  12. Polymeric nanoparticles

    PubMed Central

    Bolhassani, Azam; Javanzad, Shabnam; Saleh, Tayebeh; Hashemi, Mehrdad; Aghasadeghi, Mohammad Reza; Sadat, Seyed Mehdi

    2014-01-01

    Nanocarriers with various compositions and biological properties have been extensively applied for in vitro/in vivo drug and gene delivery. The family of nanocarriers includes polymeric nanoparticles, lipid-based carriers (liposomes/micelles), dendrimers, carbon nanotubes, and gold nanoparticles (nanoshells/nanocages). Among different delivery systems, polymeric carriers have several properties such as: easy to synthesize, inexpensive, biocompatible, biodegradable, non-immunogenic, non-toxic, and water soluble. In addition, cationic polymers seem to produce more stable complexes led to a more protection during cellular trafficking than cationic lipids. Nanoparticles often show significant adjuvant effects in vaccine delivery since they may be easily taken up by antigen presenting cells (APCs). Natural polymers such as polysaccharides and synthetic polymers have demonstrated great potential to form vaccine nanoparticles. The development of new adjuvants or delivery systems for DNA and protein immunization is an expanding research field. This review describes polymeric carriers especially PLGA, chitosan, and PEI as vaccine delivery systems. PMID:24128651

  13. Characterizing nanoparticles

    NASA Astrophysics Data System (ADS)

    Perrey, Christopher Robert

    The properties of nanoscale materials have been shown to deviate from those expected of bulk materials. In order to better understand the causes of these observations, a fundamental understanding of the structure of nanoparticles and nanostructured materials is necessary. This work focuses on the characterization of such materials using techniques of electron microscopy. Structures composed of nanoparticles and mechanically deformed, lithographically created silicon towers were analyzed using a combination of focused ion beam milling, scanning electron microscopy, and transmission electron microscopy. The nanostructured films were found to be not fully dense and composed of chemically heterogeneous areas; such specimens could not be produced using traditional methods of sample preparation. The mechanically indented towers exhibited an increased defect structure that was consistent with the increase in applied load. Additional studies focusing on individual nanoparticles produced by different plasma processes have been analyzed in terms of morphology, chemistry, and defect structure. It was found that nanoparticle morphology can be a direct indicator of the particle formation processes occurring in the plasma. Spherical particles can be formed by rapidly solidifying a liquid sphere, with a convex solid-liquid interface. Highly-oriented cubic particles are the result of a slower vapor condensation process on energetically favorable crystallographic planes. Intermediate nanoparticle shapes were encountered and indicate a transition in solidification mechanisms is possible. Using aberration-corrected high-resolution transmission electron microscopy, silicon nanoparticles as small as 1.25 nm in diameter were discovered in hydrogenated nanocrystalline silicon (a/nc-Si:H) films. Some of these nanoparticles contained twin defects and stacking faults; the structure of these planar defects indicate that the nanoparticles were formed in the plasma and not by solid-state nucleation in the film.

  14. Biocompatibility of crystalline opal nanoparticles

    PubMed Central

    2012-01-01

    Background Silica nanoparticles are being developed as a host of biomedical and biotechnological applications. For this reason, there are more studies about biocompatibility of silica with amorphous and crystalline structure. Except hydrated silica (opal), despite is presents directly and indirectly in humans. Two sizes of crystalline opal nanoparticles were investigated in this work under criteria of toxicology. Methods In particular, cytotoxic and genotoxic effects caused by opal nanoparticles (80 and 120 nm) were evaluated in cultured mouse cells via a set of bioassays, methylthiazolyldiphenyl-tetrazolium-bromide (MTT) and 5-bromo-2?-deoxyuridine (BrdU). Results 3T3-NIH cells were incubated for 24 and 72 h in contact with nanocrystalline opal particles, not presented significant statistically difference in the results of cytotoxicity. Genotoxicity tests of crystalline opal nanoparticles were performed by the BrdU assay on the same cultured cells for 24 h incubation. The reduction of BrdU-incorporated cells indicates that nanocrystalline opal exposure did not caused unrepairable damage DNA. Conclusions There is no relationship between that particles size and MTT reduction, as well as BrdU incorporation, such that the opal particles did not induce cytotoxic effect and genotoxicity in cultured mouse cells. PMID:23088559

  15. Preparation and Characterisation of Highly Loaded Fluorescent Chitosan Nanoparticles

    PubMed Central

    Katas, Haliza; Mui Wen, Chan

    2011-01-01

    Chitosan (CS) nanoparticles have been developed as a versatile drug delivery system to transport drugs, genes, proteins, and peptides into target sites. Demands on fluorescent nanoparticles have increased recently due to various applications in medical and stem-cell-based researches. In this study, fluorescent CS nanoparticles were prepared by a mild method, namely, complex coacervation. Entrapment efficiency of sulforhodamine (SR101) loaded into CS nanoparticles was investigated to evaluate their capacity in incorporating fluorescent molecule. Particle size of produced fluorescent nanoparticles was in the range of 600–700 nm, and their particle size was highly dependent on the CS molecular weight as well as concentration. A high entrapment efficiency of SR101 into CS nanoparticles could also be obtained when it was dissolved in methanol. In conclusion, highly loaded fluorescent CS nanoparticles could be easily prepared using complex coacervation method and therefore can be applied in various medical researches. PMID:22389847

  16. Nanoparticle-triggered release from lipid membrane vesicles.

    PubMed

    Reimhult, Erik

    2015-12-25

    Superparamagnetic iron oxide nanoparticles are used in a rapidly expanding number of research and practical applications in biotechnology and biomedicine. We highlight how recent developments in iron oxide nanoparticle design and understanding of nanoparticle membrane interactions have led to applications in magnetically triggered, liposome delivery vehicles with controlled structure. Nanoscale vesicles actuated by incorporated nanoparticles allow for controlling location and timing of compound release, which enables e.g. use of more potent drugs in drug delivery as the interaction with the right target is ensured. This review emphasizes recent results on the connection between nanoparticle design, vesicle assembly and the stability and release properties of the vesicles. While focused on lipid vesicles magnetically actuated through iron oxide nanoparticles, these insights are of general interest for the design of capsule and cell delivery systems for biotechnology controlled by nanoparticles. PMID:25534673

  17. Silicalites and Mesoporous Silica Nanoparticles for photodynamic therapy.

    PubMed

    Hocine, Ouahiba; Gary-Bobo, Magali; Brevet, David; Maynadier, Marie; Fontanel, Simon; Raehm, Laurence; Richeter, Sbastien; Loock, Bernard; Couleaud, Pierre; Frochot, Cline; Charnay, Clarence; Derrien, Galle; Smahi, Monique; Sahmoune, Amar; Morre, Alain; Maillard, Philippe; Garcia, Marcel; Durand, Jean-Olivier

    2010-12-15

    The synthesis of silicalites and Mesoporous Silica Nanoparticles (MSN), which covalently incorporate original water-soluble photosensitizers for PDT applications is described. PDT was performed on MDA-MB-231 breast cancer cells. All the nanoparticles showed significant cell death after irradiation, which was not correlated with (1)O(2) quantum yield of the nanoparticles. Other parameters are involved and in particular the surface and shape of the nanoparticles which influence the pathway of endocytosis. Functionalization with mannose was necessary to obtain the best results with PDT due to an active endocytosis of mannose-functionalized nanoparticles. The quantity of mannose on the surface should be carefully adjusted as a too high amount of mannose impairs the phototoxicity of the nanoparticles. Fluorescein was also encapsulated in MCM-41 type MSN in order to localize the nanoparticles in the organelles of the cells by confocal microscopy. The MSN were localized in lysosomes after active endocytosis by mannose receptors. PMID:20934496

  18. Trimetallic Ag@AuPt Neapolitan nanoparticles

    NASA Astrophysics Data System (ADS)

    Song, Yang; Chen, Shaowei

    2013-07-01

    Trimetallic Ag@AuPt Neapolitan nanoparticles were prepared by two sequential galvanic exchange reactions of 1-hexanethiolate-capped silver nanoparticles (AgC6, 5.70 +/- 0.82 nm in diameter) with gold(i)-thiomalic acid (AuITMA) and platinum(ii)-hexanethiolate (PtIIC6) complexes. The first reaction was carried out at the air-water interface by the Langmuir method where the AgC6 nanoparticles formed a compact monolayer and water-soluble AuITMA was injected into the water subphase; the nanoparticles were then deposited onto a substrate surface in the up-stroke fashion and immersed into an acetone solution of PtIIC6. As both reactions were confined to an interface, the Au and Pt elements were situated on two opposite poles of the original Ag nanoparticles. The tripatchy structure was clearly manifested in elemental mapping of the nanoparticles, and consistent with the damping and red-shift of the nanoparticle surface plasmon resonance. Further characterizations by X-ray photoelectron spectroscopy showed that the reactions were mostly confined to the top layers of the Ag metal cores, and contact angle and infrared spectroscopic measurements confirmed the incorporation and segregated distribution of the organic capping ligands on the nanoparticle surface.

  19. Gold Nanoparticle Labels Amplify Ellipsometric Signals

    NASA Technical Reports Server (NTRS)

    Venkatasubbarao, Srivatsa

    2008-01-01

    The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation. The colorimetric, polarization, light-scattering, and other optical properties of nanoparticles depend on their sizes and shapes. In the present method, these size-and-shape-dependent properties are used to magnify the polarization of scattered light and the diattenuation and retardance of signals derived from ellipsometry. The size-and-shape-dependent optical properties of the nanoparticles make it possible to interrogate the nanoparticles by use of light of various wavelengths, as appropriate, to optimally detect particles of a specific type at high sensitivity. Hence, by incorporating gold nanoparticles bound to biomolecules as primary or secondary labels, the performance of ellipsometry as a means of detecting the biomolecules can be improved. The use of gold nanoparticles as labels in ellipsometry has been found to afford sensitivity that equals or exceeds the sensitivity achieved by use of fluorescence-based methods. Potential applications for ellipsometric detection of gold nanoparticle-labeled biomolecules include monitoring molecules of interest in biological samples, in-vitro diagnostics, process monitoring, general environmental monitoring, and detection of biohazards.

  20. Using Models that Incorporate Uncertainty

    ERIC Educational Resources Information Center

    Caulkins, Jonathan P.

    2002-01-01

    In this article, the author discusses the use in policy analysis of models that incorporate uncertainty. He believes that all models should consider incorporating uncertainty, but that at the same time it is important to understand that sampling variability is not usually the dominant driver of uncertainty in policy analyses. He also argues that

  1. Preparation of drug nanoparticles by emulsion evaporation method

    NASA Astrophysics Data System (ADS)

    Hoa, Le Thi Mai; Chi, Nguyen Tai; Triet, Nguyen Minh; Thanh Nhan, Le Ngoc; Mau Chien, Dang

    2009-09-01

    Polymeric drug nanoparticles were prepared by emulsion solvent evaporation method. In this study, prepared the polymeric drug nanoparticles consist of ketoprofen and Eudragit E 100. The morphology structure was investigated by scanning electron microscopy (SEM). The interactions between the drug and polymer were investigated by Fourier transform infrared spectroscopy (FTIR). The size distribution was measured by means of Dynamic Light Scattering. The nanoparticles have an average size of about 150 nm. The incorporation ability of drugs in the polymeric nanoparticles depended on the integration between polymer and drug as well as the glass transition temperature of the polymer.

  2. Neutron reflectivity studies of composite nanoparticle - copolymer thin films

    NASA Astrophysics Data System (ADS)

    Lauter-Pasyuk, V.; Lauter, H. J.; Ausserre, D.; Gallot, Y.; Cabuil, V.; Hamdoun, B.; Kornilov, E. I.

    1998-06-01

    Neutron reflection was used for the investigation of a new class of copolymers - composite materials, consisting of symmetric polystyrene-polybuthylmethacrylate (PS-PBMA) diblock copolymer with incorporated nanoparticles ?-Fe 2O 3 of a few nanometers in diameter. The presence of the nanoparticles induces an elastic distortion of the copolymer matrix. From the experiments we obtained information about the lamellar order of the polymer matrix, the distribution of the nanoparticles in the film and the distortion of the interfaces caused by the nanoparticles.

  3. Magnetic Nanoparticles for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Jing, Ying

    Nanotechnology is revolutionizing human's life. Synthesis and application of magnetic nanoparticles is a fast burgeoning field which has potential to bring significant advance in many fields, for example diagnosis and treatment in biomedical area. Novel nanoparticles to function efficiently and intelligently are in desire to improve the current technology. We used a magnetron-sputtering-based nanocluster deposition technique to synthesize magnetic nanoparticles in gas phase, and specifically engineered nanoparticles for different applications. Alternating magnetic field heating is emerging as a technique to assist cancer treatment or drug delivery. We proposed high-magnetic-moment Fe3Si particles with relatively large magnetic anisotropy energy should in principle provide superior performance. Such nanoparticles were experimentally synthesized and characterized. Their promising magnetic properties can contribute to heating performance under suitable alternating magnetic field conditions. When thermal energy is used for medical treatment, it is ideal to work in a designed temperature range. Biocompatible and "smart" magnetic nanoparticles with temperature self-regulation were designed from both materials science and biomedicine aspects. We chose Fe-Si material system to demonstrate the concept. Temperature dependent physical property was adjusted by tuning of exchange coupling between Fe atoms through incorporation of various amount of Si. The magnetic moment can still be kept in a promising range. The two elements are both biocompatible, which is favored by in-vivo medical applications. A combination of "smart" magnetic particles and thermo-sensitive polymer were demonstrated to potentially function as a platform for drug delivery. Highly sensitive diagnosis for point-of-care is in desire nowadays. We developed composition- and phase-controlled Fe-Co nanoparticles for bio-molecule detection. It has been demonstrated that Fe70Co30 nanoparticles and giant magnetoresistance sensor make a successful integrated system for bio-molecule detection. In addition, we proposed the concept of "magnetic coloring": magnetic nanoparticles with different M-H loop form an archive of labels for detection of multiple molecules in the same sample. The composition- and phase- controlled Fe-Co particles are candidate to serve this application. Magnetic nanoparticles can also play a role in "green" catalysis. We synthesized core-shell structured nanoparticle with core rich in Fe, and shell rich in FeSiO, which have capability for phtocatalysis and magnetic recycling. The magnetic core enables recycling of catalysts by applying an external magnetic field. The shell shows good optical absorption which indicates the possibility of phtocatalysis. A big challenge for nanoparticles synthesized in gas phase is to transfer them into aqueous environment, especially in biomedical field. We experimented different approaches to modify the surface of magnetic nanoparticles. A direct way was developed to introduce functional molecule onto the surface of nanoparticles in vacuum. A new design of nanoparticle collection was implemented to assist surface modification in vacuum and to enable large quantity of manufacturing.

  4. Hybrid Nanoparticles for Detection and Treatment of Cancer

    PubMed Central

    Sailor, Michael J.; Park, Ji-Ho

    2012-01-01

    There is currently considerable effort to incorporate both diagnostic and therapeutic functions into a single nanoscale system for the more effective treatment of cancer. Nanoparticles have great potential to achieve such dual functions, particularly if more than one type of nanostructure can be incorporated in a nanoassemblyreferred to in this review as a hybrid nanoparticle. Here we review recent developments in the synthesis and evaluation of such hybrid nanoparticles based on two design strategies (barge vs. tanker), in which liposomal, micellar, porous silica, polymeric, viral, noble metal, and nanotube systems are incorporated either within (barge) or at the surface of (tanker) a nanoparticle. We highlight the design factors that should be considered to obtain effective nanodevices for cancer detection and treatment. PMID:22610698

  5. Co-administration of non-carrier nanoparticles boosts antigen immune response without requiring protein conjugation.

    PubMed

    Wibowo, Nani; Chuan, Yap P; Seth, Arjun; Cordoba, Yoann; Lua, Linda H L; Middelberg, Anton P J

    2014-06-17

    Nanotechnology promises a revolution in medicine including through new vaccine approaches. The use of nanoparticles in vaccination has, to date, focused on attaching antigen directly to or within nanoparticle structures to enhance antigen uptake by immune cells. Here we question whether antigen incorporation with the nanoparticle is actually necessary to boost vaccine effectiveness. We show that the immunogenicity of a sub-unit protein antigen was significantly boosted by formulation with silica nanoparticles even without specific conjugation of antigen to the nanoparticle. We further show that this effect was observed only for virus-sized nanoparticles (50 nm) but not for larger (1,000 nm) particles, demonstrating a pronounced effect of nanoparticle size. This non-attachment approach has potential to radically simplify the development and application of nanoparticle-based formulations, leading to safer and simpler nanoparticle applications in vaccine development. PMID:24793947

  6. Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products.

    PubMed

    Kavitha Sankar, P C; Ramakrishnan, Reshmi; Rosemary, M J

    2016-04-01

    Cellulose pulp has a visible market share in personal hygiene products such as sanitary napkins and baby diapers. However it offers good surface for growth of microorganisms. Huge amount of research is going on in developing hygiene products that do not initiate microbial growth. The objective of the present work is to produce antibacterial cellulose pulp by depositing silver nanopowder on the cellulose fiber. The silver nanoparticles used were of less than 100nm in size and were characterised using transmission electron microscopy and X-ray powder diffraction studies. Antibacterial activity of the functionalized cellulose pulp was proved by JIS L 1902 method. The in-vitro cytotoxicity, in-vivo vaginal irritation and intracutaneous reactivity studies were done with silver nanopowder incorporated cellulose pulp for introducing a new value added product to the market. Cytotoxicity evaluation suggested that the silver nanoparticle incorporated cellulose pulp is non-cytotoxic. No irritation and skin sensitization were identified in animals tested with specific extracts prepared from the test material in the in-vivo experiments. The results indicated that the silver nanopowder incorporated cellulose pulp meets the requirements of the standard practices recommended for evaluating the biological reactivity and has good biocompatibility, hence can be classified as a safe hygiene product. PMID:26838891

  7. Nanoparticle Solubility in Liquid Crystalline Defects

    NASA Astrophysics Data System (ADS)

    Whitmer, Jonathan K.; Armas-Perez, Julio C.; Joshi, Abhijeet A.; Roberts, Tyler F.; de Pablo, Juan J.

    2013-03-01

    Liquid crystalline materials often incorporate regions (defects) where the orientational ordering present in the bulk phase is disrupted. These include point hedgehogs, line disclinations, and domain boundaries. Recently, it has been shown that defects will accumulate impurities such as small molecules, monomer subunits or nanoparticles. Such an effect is thought to be due to the alleviation of elastic stresses within the bulk phase, or to a solubility gap between a nematic phase and the isotropic defect core. This presents opportunities for encapsulation and sequestration of molecular species, in addition to the formation of novel structures within a nematic phase through polymerization and nanoparticle self-assembly. Here, we examine the solubility of nanoparticles within a coarse-grained liquid crystalline phase and demonstrate the effects of nanoparticle size and surface interactions in determining sequestration into defect regions.

  8. Poly(amidoamine)-Cholesterol Conjugate Nanoparticles Obtained by Electrospraying as Novel Tamoxifen Delivery System

    PubMed Central

    Cavalli, R.; Bisazza, A.; Bussano, R.; Trotta, M.; Civra, A.; Lembo, D.; Ranucci, E.; Ferruti, P.

    2011-01-01

    A new poly(amidoamine)-cholesterol (PAA-cholesterol) conjugate was synthesized, characterized and used to produce nanoparticles by the electrospraying technique. The electrospraying is a method of liquid atomization that consists in the dispersion of a solution into small charged droplets by an electric field. Tuning the electrospraying process parameters spherical PAA-chol nanoparticles formed. The PAA-cholesterol nanoparticles showed sizes lower than 500?nm and spherical shape. The drug incorporation capacity was investigated using tamoxifen, a lipophilic anticancer drug, as model drug. The incorporation of the tamoxifen did not affect the shape and sizes of nanoparticles showing a drug loading of 40%. Tamoxifen-loaded nanoparticles exhibited a higher dose-dependent cytotoxicity than free tamoxifen, while blank nanoparticles did not show any cytotoxic effect at the same concentrations. The electrospray technique might be proposed to produce tamoxifen-loaded PAA-chol nanoparticle in powder form without any excipient in a single step. PMID:21785731

  9. Gold Nanoparticle Quantitation by Whole Cell Tomography.

    PubMed

    Sanders, Aric W; Jeerage, Kavita M; Schwartz, Cindi L; Curtin, Alexandra E; Chiaramonti, Ann N

    2015-12-22

    Many proposed biomedical applications for engineered gold nanoparticles require their incorporation by mammalian cells in specific numbers and locations. Here, the number of gold nanoparticles inside of individual mammalian stem cells was characterized using fast focused ion beam-scanning electron microscopy based tomography. Enhanced optical microscopy was used to provide a multiscale map of the in vitro sample, which allows cells of interest to be identified within their local environment. Cells were then serially sectioned using a gallium ion beam and imaged using a scanning electron beam. To confirm the accuracy of single cross sections, nanoparticles in similar cross sections were imaged using transmission electron microscopy and scanning helium ion microscopy. Complete tomographic series were then used to count the nanoparticles inside of each cell and measure their spatial distribution. We investigated the influence of slice thickness on counting single particles and clusters as well as nanoparticle packing within clusters. For 60 nm citrate stabilized particles, the nanoparticle cluster packing volume is 2.15 0.20 times the volume of the bare gold nanoparticles. PMID:26563983

  10. Core-shell biopolymer nanoparticle delivery systems: synthesis and characterization of curcumin fortified zein-pectin nanoparticles.

    PubMed

    Hu, Kun; Huang, Xiaoxia; Gao, Yongqing; Huang, Xulin; Xiao, Hang; McClements, David Julian

    2015-09-01

    Biopolymer core-shell nanoparticles were fabricated using a hydrophobic protein (zein) as the core and a hydrophilic polysaccharide (pectin) as the shell. Particles were prepared by coating cationic zein nanoparticles with anionic pectin molecules using electrostatic deposition (pH 4). The core-shell nanoparticles were fortified with curcumin (a hydrophobic bioactive molecule) at a high loading efficiency (>86%). The resulting nanoparticles were spherical, relatively small (diameter ≈ 250 nm), and had a narrow size distribution (polydispersity index ≈ 0.24). The encapsulated curcumin was in an amorphous (rather than crystalline form) as detected by differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) and Raman spectra indicated that the encapsulated curcumin interacted with zein mainly through hydrophobic interactions. The nanoparticles were converted into a powdered form that had good water-dispersibility. These core-shell biopolymer nanoparticles could be useful for incorporating curcumin into functional foods and beverages, as well as dietary supplements and pharmaceutical products. PMID:25842338

  11. Towards the Rational Design of Nanoparticle Catalysts

    NASA Astrophysics Data System (ADS)

    Dash, Priyabrat

    This research is focused on development of routes towards the rational design of nanoparticle catalysts. Primarily, it is focused on two main projects; (1) the use of imidazolium-based ionic liquids (ILs) as greener media for the design of quasi-homogeneous nanoparticle catalysts and (2) the rational design of heterogeneous-supported nanoparticle catalysts from structured nanoparticle precursors. Each project has different studies associated with the main objective of the design of nanoparticle catalysts. In the first project, imidazolium-based ionic liquids have been used for the synthesis of nanoparticle catalysts. In particular, studies on recyclability, reuse, mode-of-stability, and long-term stability of these ionic-liquid supported nanoparticle catalysts have been done; all of which are important factors in determining the overall "greenness" of such synthetic routes. Three papers have been published/submitted for this project. In the first publication, highly stable polymer-stabilized Au, Pd and bimetallic Au-Pd nanoparticle catalysts have been synthesized in imidazolium-based 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) ionic liquid (Journal of Molecular Catalysis A: Chemical, 2008, 286, 114). The resulting nanoparticles were found to be effective and selective quasi-homogeneous catalysts towards a wide-range of hydrogenation reactions and the catalyst solution was reused for further catalytic reactions with minimal loss in activity. The synthesis of very pure and clean ILs has allowed a platform to study the effects of impurities in the imidazolium ILs on nanoparticle stability. In a later study, a new mode of stabilization was postulated where the presence of low amounts of 1-methylimidazole has substantial effects on the resulting stability of Au and Pd-Au nanoparticles in these ILs (Chemical Communications, 2009, 812). In further continuation of this study, a comparative study involving four stabilization protocols for nanoparticle stabilization in BMIMPF6 IL is described, and have shown that nanoparticle stability and catalytic activity of nanoparticles is dependent on the overall stability of the nanoparticles towards aggregation (manuscript submitted). The second major project is focused on synthesizing structurally well-defined supported catalysts by incorporating the nanoparticle precursors (both alloy and core shell) into oxide frameworks (TiO2 and Al2O 3), and examining their structure-property relationships and catalytic activity. a full article has been published on this project (Journal of Physical Chemistry C, 2009, 113, 12719) in which a route to rationally design supported catalysts from structured nanoparticle precursors with precise control over size, composition, and internal structure of the nanoparticles has been shown. In a continuation of this methodology for the synthesis of heterogeneous catalysts, efforts were carried out to apply the same methodology in imidazolium-based ILs as a one-pot media for the synthesis of supported-nanoparticle heterogeneous catalysts via the trapping of pre-synthesized nanoparticles into porous inorganic oxide materials. Nanoparticle catalysts in highly porous titania supports were synthesized using this methodology (manuscript to be submitted).

  12. Incorporating externalities in conservation programs

    SciTech Connect

    Jordan, J.L.

    1995-06-01

    As water utilities incorporate integrated resource planning in their management processes, it is necessary to incorporate the concept of externalities. This is particularly important as methods evolve of evaluating the costs and benefits of water conservation programs. The purpose of this article is to provide an introduction to the issues surrounding externalities, including their definition, methods of internalizing externalities, and a survey of ways to estimate costs and benefits of externalities. Although most discussions of externalities emphasize negative effects on the environment, this article will illustrate both positive and negative externalities associated with practicing water conservation.

  13. Selenium incorporation using recombinant techniques

    SciTech Connect

    Walden, Helen

    2010-04-01

    An overview of techniques for recombinant incorporation of selenium and subsequent purification and crystallization of the resulting labelled protein. Using selenomethionine to phase macromolecular structures is common practice in structure determination, along with the use of selenocysteine. Selenium is consequently the most commonly used heavy atom for MAD. In addition to the well established recombinant techniques for the incorporation of selenium in prokaryal expression systems, there have been recent advances in selenium labelling in eukaryal expression, which will be discussed. Tips and things to consider for the purification and crystallization of seleno-labelled proteins are also included.

  14. Physicochemical signatures of nanoparticle-dependent complement activation

    SciTech Connect

    Thomas, Dennis G.; Chikkagoudar, Satish; Heredia-Langner, Alejandro; Tardiff, Mark F.; Xu, Zhixiang; Hourcade, Dennis; Pham, Christine; Lanza, Gregory M.; Weinberger, Kilian Q.; Baker, Nathan A.

    2014-03-21

    Nanoparticles are potentially powerful therapeutic tools that have the capacity to target drug payloads and imaging agents. However, some nanoparticles can activate complement, a branch of the innate immune system, and cause adverse side-effects. Recently, we developed an in vitro hemolytic assay protocol for measuring the nanoparticle-dependent complement activity of serum samples and applied this protocol to several nanoparticle formulations that differed in size, surface charge, and surface chemistry; quantifying the nanoparticle-dependent complement activity using a metric called Residual Hemolytic Activity (RHA). In the present work, we have used a decision tree learning algorithm to derive the rules for estimating nanoparticle-dependent complement response based on the data generated from the hemolytic assay studies. Our results indicate that physicochemical properties of nanoparticles, namely, size, polydispersity index, zeta potential, and mole percentage of the active surface ligand of a nanoparticle, can serve as good descriptors for prediction of nanoparticle-dependent complement activation in the decision tree modeling framework. The robustness and predictability of the model can be improved by training the model with additional data points that are uniformly distributed in the RHA/physicochemical descriptor space and by incorporating instability effects on nanoparticle physicochemical properties into the model.

  15. Apoferritin-Templated Synthesis of Encoded Metallic Phosphate Nanoparticle Tags

    SciTech Connect

    Liu, Guodong; Wu, Hong; Dohnalkova, Alice; Lin, Yuehe

    2007-07-31

    Encoded metallic-phosphate nanoparticle tags, with distinct encoding patterns, have been prepared using an apoferritin template. A center-cavity structure as well as the disassociation and reconstructive characteristics of apoferritin at different pH environments provide a facile route for preparing such encoded nanoparticle tags. Encapsulation and diffusion approaches have been investigated during the preparation. The encapsulation approach, which is based on the dissociation and reconstruction of apoferritin at different pHs, exhibits an effective route to prepare such encoded metallic-phosphate nanoparticle tags. The compositionally encoded nanoparticle tag leads to a high coding capacity with a large number of distinguishable voltammetric signals, reflecting the predetermined composition of the metal mixture solution (and hence the nanoparticle composition). Releasing the metal components from the nanoparticle tags at pH 4.6 acetate buffer avoids harsh dissolution conditions, such as strong acids. Such a synthesis of encoded nanoparticle tags, including single-component and compositionally encoded nanoparticle tags, is substantially simple, fast, and convenient compared to that of encoded metal nanowires and semiconductor nanoparticle (CdS, PbS, and ZnS) incorporated polystyrene beads. The encoded metallic-phosphate nanoparticle tags thus show great promise for bioanalytical or product-tracking/identification/protection applications.

  16. Multiscale study of metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Lee, Byeongchan

    Extremely small structures with reduced dimensionality have emerged as a scientific motif for their interesting properties. In particular, metal nanoparticles have been identified as a fundamental material in many catalytic activities; as a consequence, a better understanding of structure-function relationship of nanoparticles has become crucial. The functional analysis of nanoparticles, reactivity for example, requires an accurate method at the electronic structure level, whereas the structural analysis to find energetically stable local minima is beyond the scope of quantum mechanical methods as the computational cost becomes prohibitingly high. The challenge is that the inherent length scale and accuracy associated with any single method hardly covers the broad scale range spanned by both structural and functional analyses. In order to address this, and effectively explore the energetics and reactivity of metal nanoparticles, a hierarchical multiscale modeling is developed, where methodologies of different length scales, i.e. first principles density functional theory, atomistic calculations, and continuum modeling, are utilized in a sequential fashion. This work has focused on identifying the essential information that bridges two different methods so that a successive use of different methods is seamless. The bond characteristics of low coordination systems have been obtained with first principles calculations, and incorporated into the atomistic simulation. This also rectifies the deficiency of conventional interatomic potentials fitted to bulk properties, and improves the accuracy of atomistic calculations for nanoparticles. For the systematic shape selection of nanoparticles, we have improved the Wulff-type construction using a semi-continuum approach, in which atomistic surface energetics and crystallinity of materials are added on to the continuum framework. The developed multiscale modeling scheme is applied to the rational design of platinum nanoparticles in the range of 2.4 nm to 3.1 nm: energetically favorable structures have been determined in terms of semi-continuum binding energy, and the reactivity of the selected nanoparticle has been investigated based on local density of states from first principles calculations. The calculation suggests that the reactivity landscape of particles is more complex than the simple reactivity of clean surfaces, and the reactivity towards a particular reactant can be predicted for a given structure.

  17. Earth abundant bimetallic nanoparticles for heterogeneous catalysis

    NASA Astrophysics Data System (ADS)

    Senn, Jonathan F., Jr.

    Polymer exchange membrane fuel cells have the potential to replace current fossil fuel-based technologies in terms of emissions and efficiency, but CO contamination of H2 fuel, which is derived from steam methane reforming, leads to system inefficiency or failure. Solutions currently under development are bimetallic nanoparticles comprised of earth-abundant metals in different architectures to reduce the concentration of CO by PROX during fuel cell operation. Chapter One introduces the Pt-Sn and Co-Ni bimetallic nanoparticle systems, and the intermetallic and core-shell architectures of interest for catalytic evaluation. Application, theory, and studies associated with the efficacy of these nanoparticles are briefly reviewed. Chapter Two describes the concepts of the synthetic and characterization methods used in this work. Chapter Three presents the synthetic, characterization, and catalytic findings of this research. Pt, PtSn, PtSn2, and Pt 3Sn nanoparticles have been synthesized and supported on gamma-Al2O3. Pt3Sn was shown to be an effective PROX catalyst in various gas feed conditions, such as the gas mixture incorporating 0.1% CO, which displayed a light-off temperatures of 95C. Co and Ni monometallic and CoNi bimetallic nanoparticles have been synthesized and characterized, ultimately leading to the development of target Co Ni core-shell nanoparticles. Proposed studies of catalytic properties of these nanoparticles in preferential oxidation of CO (PROX) reactions will further elucidate the effects of different crystallographic phases, nanoparticle-support interactions, and architecture on catalysis, and provide fundamental understanding of catalysis with nanoparticles composed of earth abundant metals in different architectures.

  18. Incorporating Argumentation through Forensic Science

    ERIC Educational Resources Information Center

    Wheeler, Lindsay B.; Maeng, Jennifer L.; Smetana, Lara K.

    2014-01-01

    This article outlines how to incorporate argumentation into a forensic science unit using a mock trial. Practical details of the mock trial include: (1) a method of scaffolding students' development of their argument for the trial, (2) a clearly outlined set of expectations for students during the planning and implementation of the mock

  19. Incorporating Argumentation through Forensic Science

    ERIC Educational Resources Information Center

    Wheeler, Lindsay B.; Maeng, Jennifer L.; Smetana, Lara K.

    2014-01-01

    This article outlines how to incorporate argumentation into a forensic science unit using a mock trial. Practical details of the mock trial include: (1) a method of scaffolding students' development of their argument for the trial, (2) a clearly outlined set of expectations for students during the planning and implementation of the mock…

  20. Modeling the heterogeneous catalytic activity of a single nanoparticle using a first passage time distribution formalism

    NASA Astrophysics Data System (ADS)

    Das, Anusheela; Chaudhury, Srabanti

    2015-11-01

    Metal nanoparticles are heterogeneous catalysts and have a multitude of non-equivalent, catalytic sites on the nanoparticle surface. The product dissociation step in such reaction schemes can follow multiple pathways. Proposed here for the first time is a completely analytical theoretical framework, based on the first passage time distribution, that incorporates the effect of heterogeneity in nanoparticle catalysis explicitly by considering multiple, non-equivalent catalytic sites on the nanoparticle surface. Our results show that in nanoparticle catalysis, the effect of dynamic disorder is manifested even at limiting substrate concentrations in contrast to an enzyme that has only one well-defined active site.

  1. Controlling particle size in the Stöber process and incorporation of calcium.

    PubMed

    Greasley, Sarah L; Page, Samuel J; Sirovica, Slobodan; Chen, Shu; Martin, Richard A; Riveiro, Antonio; Hanna, John V; Porter, Alexandra E; Jones, Julian R

    2016-05-01

    The Stӧber process is commonly used for synthesising spherical silica particles. This article reports the first comprehensive study of how the process variables can be used to obtain monodispersed particles of specific size. The modal particle size could be selected within in the range 20-500nm. There is great therapeutic potential for bioactive glass nanoparticles, as they can be internalised within cells and perform sustained delivery of active ions. Biodegradable bioactive glass nanoparticles are also used in nanocomposites. Modification of the Stӧber process so that the particles can contain cations such as calcium, whilst maintaining monodispersity, is desirable. Here, whilst calcium incorporation is achieved, with a homogenous distribution, careful characterisation shows that much of the calcium is not incorporated. A maximum of 10mol% CaO can be achieved and previous reports are likely to have overestimated the amount of calcium incorporated. PMID:26890387

  2. Eugenol-loaded chitosan nanoparticles: II. Application in bio-based plastics for active packaging.

    PubMed

    Woranuch, Sarekha; Yoksan, Rangrong

    2013-07-25

    The aim of the present research was to study the possibility of using eugenol-loaded chitosan nanoparticles as antioxidants for active bio-based packaging material. Eugenol-loaded chitosan nanoparticles were incorporated into thermoplastic flour (TPF) - a model bio-based plastic - through an extrusion process at temperatures above 150°C. The influences of eugenol-loaded chitosan nanoparticles on crystallinity, morphology, thermal properties, radical scavenging activity, reducing power, tensile properties and barrier properties of TPF were investigated. Although the incorporation of 3% (w/w) of eugenol-loaded chitosan nanoparticles significantly reduced the extensibility and the oxygen barrier property of TPF, it provided antioxidant activity and improved the water vapor barrier property. In addition, TPF containing eugenol-loaded chitosan nanoparticles exhibited superior radical scavenging activity and stronger reducing power compared with TPF containing naked eugenol. The results suggest the applicability of TPF containing eugenol-loaded chitosan nanoparticles as an antioxidant active packaging material. PMID:23768604

  3. Formation and characterization of nanoparticles via laser ablation in solution

    NASA Astrophysics Data System (ADS)

    Golightly, Justin Samuel

    The work presented in this thesis encompassed laser ablation of various transition metals within a liquid environment. Through an improved understanding of the ablation process, control over the properties of the resultant nanoparticles can be obtained, and thusly nanoparticles can be tailored with specific properties. Creation of nanoparticles via laser ablation in solution is a relatively youngtechnique for nanoparticle synthesis, and the work presented should prove useful in guiding further exploration in ablation processes in liquids for nanomaterial production. When a laser is focused onto a target under a liquid environment, the target material and its surrounding liquid are vaporized. The concoction of vapor is ejected normal to the surface as a bubble. The bubble has a temperature reaching the boiling point of the metal, and has a gradient to the boiling point of the solvent. The bubble expands until it reaches a critical volume, and then subsequently collapses. It is within this bubble that nanoparticle formation occurs. As the bubble expands, the vapor cools and nanoparticle growth transpires. During the bubble collapse, pressures reaching GigaPascals have been reported, and a secondary nanoparticle formation occurs as a result of these high pressures. Chapter 1 delves a little more into the nanoparticle formation mechanisms, as well as an introduction to the analytical techniques used for characterization. Ablation of titanium took place in isopropanol, ethanol, water, and n-hexane, under various fluences, with a 532 nm Nd:YAG operating at 10 Hz. It was found that a myriad of nanoparticles could be made with vastly different compositions that were both solvent and fluence dependent. Nanoparticles were made that incorporated carbon and oxygen from the solvent, showing how solvent choice is an important factor in nanoparticle creation. Chapter 3 discusses the results of the titanium work in great detail and demonstrates carbide production with ablation in isopropyl alcohol. Ablation in n-hexane also showed diffraction patterns correlating with carbides, and water showed oxygen incorporation. These results showed the ability to utilize the solvent in tailoring nanoparticles to achieve desired properties. Zirconium and nickel were ablated with the Nd:YAG at 532 nm. These studies utilized a stainless steel chamber designed and built to improve control over the experimental variables. The nickel study showcased the new chamber's ability for reproducibility in a size dependence study based upon laser fluence. The results of ablation with the Nd:YAG were compared to femtosecond ablation experiments performed with a titanium:sapphire femtosecond laser system. The Ti:sapphire femtosecond laser operated at 10 Hz, produced femtosecond pulses centered at 795 nm. The pulse duration was varied from 100 fs to 390 fs, the nanoparticles created from each condition were characterized, and the results are presented in chapters 5 and 6. Aluminum nanoparticles were made using both nanosecond and femtosecond laser ablation techniques. Aluminum nanoparticles have a great deal of potential for use as fuel additives as well as in paints and coatings. The nanosecond ablation process rendered large nanoparticles (over 200 nm) and the results are briefly shown in Appendix A. The femtosecond system produced a much smaller distribution of nanoparticles, with nanoparticles remaining in suspension for over a month's time, as evidenced by their unique UV-Vis absorbance. These nanoparticles were produced in isopropyl alcohol, and were stabilized by the solvent, as TEM analysis showed nanoparticles with very little oxygen incorporation. The solvent is bound to the nanoparticles as a result of the formation process and as a result forms a protective coating, which prevents further oxidation over time. The remarkable stability of these aluminum nanoparticles is a testament of employing the high energy scheme of the laser ablation process in a manner to tailor the production of novel nanomaterials. (Abstract shortened by UMI.)

  4. Formation and material analysis of plasma polymerized carbon nitride nanoparticles

    NASA Astrophysics Data System (ADS)

    Kovačević, E.; Berndt, J.; Stefanović, I.; Becker, H.-W.; Godde, C.; Strunskus, Th.; Winter, J.; Boufendi, L.

    2009-05-01

    This paper deals with the analysis of nanoparticles polymerized in nitrogen/acetylene and argon/acetylene gas mixtures in low temperature rf discharges. The polymerization process was monitored by means of mass spectroscopy. The chemical characteristics of the material were obtained in situ by infrared absorption spectroscopy and ex situ by means of near edge x-ray absorption fine structure spectroscopy. These data were supported by complimentary elemental analyses such as deuteron induced gamma emission, Rutherford backscattering, and nuclear reaction analysis. Although morphology showed no differences, further material analysis shows clearly nitrogen incorporation in the nanoparticles, mostly by multiple bonds. In comparison with the nanoparticles from argon/acetylene plasma, the amount of carbon in carbon-nitride nanoparticles remains unchanged, whereas hydrogen content strongly decreases. The results of mass spectroscopy on neutrals and ions lead to the assumption that carbon-nitride nanoparticles are formed by copolymerization of two kinds of precursors: hydrocarbon and nitrogen containing hydrocarbon species.

  5. Al(OH)3 facilitated synthesis of water-soluble, magnetic, radiolabelled and fluorescent hydroxyapatite nanoparticles.

    PubMed

    Cui, X; Green, M A; Blower, P J; Zhou, D; Yan, Y; Zhang, W; Djanashvili, K; Mathe, D; Veres, D S; Szigeti, K

    2015-06-01

    Magnetic and fluorescent hydroxyapatite nanoparticles were synthesised using Al(OH)3-stabilised MnFe2O4 or Fe3O4 nanoparticles as precursors. They were readily and efficiently radiolabelled with (18)F. Bisphosphonate polyethylene glycol polymers were utilised to endow the nanoparticles with excellent colloidal stability in water and to incorporate cyclam for high affinity labelling with (64)Cu. PMID:25960059

  6. Molecular imaging and therapy of cancer with radiolabeled nanoparticles

    PubMed Central

    Hong, Hao; Zhang, Yin; Sun, Jiangtao; Cai, Weibo

    2009-01-01

    Summary This review summarizes the current state-of-the-art of radiolabeled nanoparticles for molecular imaging and internal radiotherapy applications targeting cancer. With the capacity to provide enormous flexibility, radiolabeled nanoparticles have the potential to profoundly impact disease diagnosis and patient management in the near future. Currently, the major challenges facing the research on radiolabeled nanoparticles are desirable (tumor) targeting efficacy, robust chemistry for both radionuclide encapsulation/incorporation and targeting ligand conjugation, favorable safety profile, as well as certain commercial and regulatory hurdles. PMID:20161038

  7. Design of biodegradable nanoparticles: a novel approach to encapsulating poorly soluble phytochemical ellagic acid

    NASA Astrophysics Data System (ADS)

    Bala, I.; Bhardwaj, V.; Hariharan, S.; Sitterberg, J.; Bakowsky, U.; Kumar, M. N. V. Ravi

    2005-12-01

    Nanosizing of poorly water soluble drugs or incorporating them into nanoparticles to increase their solubility and thereby the bioavailability has become a favoured approach today. This work describes a novel method for encapsulating poorly water soluble phytochemical ellagic acid that is also sparingly soluble/insoluble in routine solvents used to prepare nanoparticles.

  8. Controlled cobalt doping in biogenic magnetite nanoparticles.

    PubMed

    Byrne, J M; Coker, V S; Moise, S; Wincott, P L; Vaughan, D J; Tuna, F; Arenholz, E; van der Laan, G; Pattrick, R A D; Lloyd, J R; Telling, N D

    2013-06-01

    Cobalt-doped magnetite (CoxFe3 -xO4) nanoparticles have been produced through the microbial reduction of cobalt-iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mssbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe(2+) site with Co(2+), with up to 17 per cent Co substituted into tetrahedral sites. PMID:23594814

  9. Controlled cobalt doping in biogenic magnetite nanoparticles

    PubMed Central

    Byrne, J. M.; Coker, V. S.; Moise, S.; Wincott, P. L.; Vaughan, D. J.; Tuna, F.; Arenholz, E.; van der Laan, G.; Pattrick, R. A. D.; Lloyd, J. R.; Telling, N. D.

    2013-01-01

    Cobalt-doped magnetite (CoxFe3 −xO4) nanoparticles have been produced through the microbial reduction of cobalt–iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe2+ site with Co2+, with up to 17 per cent Co substituted into tetrahedral sites. PMID:23594814

  10. Allergen immunotherapy with nanoparticles containing lipopolysaccharide from Brucella ovis.

    PubMed

    Gmez, Sara; Gamazo, Carlos; San Roman, Beatriz; Ferrer, Marta; Sanz, Maria Luisa; Espuelas, Socorro; Irache, Juan M

    2008-11-01

    The adjuvant and protective capacity against anaphylactic shock of the association between rough lipopolysaccharide of Brucella ovis (LPS) coencapsulated with ovalbumin (OVA), as a model allergen, in Gantrez AN nanoparticles was investigated. Several strategies were performed in order to study the adjuvant effect of the LPS either encapsulated or coating the nanoparticles. OVA, as well as LPS, was incorporated either during the manufacturing process (OVA-encapsulated or LPS-encapsulated nanoparticles, respectively) or after the preparation (OVA-coated or LPS-coated nanoparticles, respectively). After the administration of 10 microg of OVA incorporated in the different formulations, all the nanoparticles, with or without LPS, were capable of amplifying the immune response (IgG(1) and IgG(2a)). However, in a model of sensitized mice to OVA, the formulation with OVA and LPS-entrapped inside the nanoparticles administered intradermally in three doses of 3 microg of OVA each was the only treatment that totally protected the mice from death after a challenge with an intraperitoneal injection of OVA. In contrast, the control group administered with OVA adsorbed onto a commercial alhydrogel adjuvant showed 80% mortality. These results are highly suggestive for the valuable use of Gantrez nanoparticles combined with rough LPS of B. ovis in immunotherapy. PMID:18582571

  11. Fabrication and characterization of magnetic nanoparticle composite membranes

    NASA Astrophysics Data System (ADS)

    Cruickshank, Akeem Armand

    To effectively and accurately deliver drugs within the human body, both new designs and components for implantable micropumps are being studied. Designs must ensure high biocompatibility, drug compatibility, accuracy and small power consumption. The focus of this thesis was to fabricate a prototype magnetic nanoparticle membrane for eventual incorporation into a biomedical pump and then determine the relationship between this membrane deflection and applied pneumatic or magnetic force. The magnetic nanoparticle polymer composite (MNPC) membranes in this study were composed of crosslinked polydimethylsiloxane (PDMS) and iron oxide nanoparticles (IONPs). An optimal iron oxide fabrication route was identified and particle size in each batch was approximately 24.6 nm. Once these nanoparticles were incorporated into a membrane (5 wt. %), the nanoparticle formed agglomerates with an average diameter of 2.26 +/-1.23 microm. Comparisons between the 0 and 5 wt. % loading of particles into the membranes indicated that the elastic modulus of the composite decreased with increasing particle concentration. The pressure- central deflection of the membranes could not be predicated by prior models and variation between magnetic and pneumatic pressure-deflection curves was quantified. Attempts to fabricate membranes with above 5 wt. % nanoparticles were not successful (no gelation). Fourier Transform Infrared (FTIR) spectroscopy results suggest that excess oleic acid on the nanoparticles prior to mixing might have prevented crosslinking.

  12. Antibacterial releasing titanium surface using albumin nanoparticle carriers.

    PubMed

    Kim, Da Hye; Kim, Kyo-Han; Kwon, Tae-Yub; Choi, Seok Hwa; Kang, Seong Soo; Kwon, Soon-Taek; Cho, Dae-Hyun; Kim, Hee Dong; Son, Jun Sik

    2014-11-01

    We developed a simple and highly efficient method for delivery from titanium (Ti) surfaces using albumin nanoparticle carriers. A Ti disc with a resorbable blasting media surface was used as a metal implant with a localized drug delivery structure. Human serum albumin (HSA) nanoparticles loaded with chlorhexidine (CHX) diacetate salt hydrate as the model drug were fabricated using a desolvation technique. The CHX-loaded HSA nanoparticles produced were cross linked with glutaraldehyde (GA). The nanoparticles were pre-coated with positively-charged polyethylenimine (PEI) molecules and then immobilized via electrical interactions on the negatively charged Ti disc surface. Our results suggested that the PEI-coated HSA nanoparticles loaded with CHX (PEI-CHX-HSA) were incorporated successfully and well-dispersed on the Ti disc surfaces. The agar diffusion test on the Ti surface treated with PEI-CHX-HSA nanoparticles showed a larger growth inhibition zone of Streptococcus mutans versus the control Ti surface, suggesting that this innovative delivery platform imparts potent antibacterial activity to the Ti surface. Thus, CHX, which inhibits the growth of oral bacteria, can be efficiently incorporated onto Ti surfaces by using HSA nanoparticles. PMID:25958539

  13. Uranium incorporation into amorphous silica.

    PubMed

    Massey, Michael S; Lezama-Pacheco, Juan S; Nelson, Joey M; Fendorf, Scott; Maher, Kate

    2014-01-01

    High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal. Here, we examine the coordination environment of U within opaline silica to elucidate incorporation mechanisms. Precipitates (with and without ferrihydrite inclusions) were synthesized from U-bearing sodium metasilicate solutions, buffered at pH ? 5.6. Natural and synthetic solids were analyzed with X-ray absorption spectroscopy and a suite of other techniques. In synthetic amorphous silica, U was coordinated by silicate in a double corner-sharing coordination geometry (Si at ? 3.8-3.9 ) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ? 3.1-3.2 , U at ? 3.8-3.9 ). In iron-bearing synthetic solids, U was adsorbed to iron (hydr)oxide, but the coordination environment also contained silicate in both edge-sharing and corner-sharing coordination. Uranium local coordination in synthetic solids is similar to that of natural U-bearing opals that retain U for millions of years. The stability and extent of U incorporation into opaline and amorphous silica represents a long-term repository for U that may provide an alternative strategy for remediation of U contamination. PMID:24984107

  14. Antimicrobial polymers with metal nanoparticles.

    PubMed

    Palza, Humberto

    2015-01-01

    Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms. PMID:25607734

  15. Antimicrobial Polymers with Metal Nanoparticles

    PubMed Central

    Palza, Humberto

    2015-01-01

    Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms. PMID:25607734

  16. Incorporating Spirituality in Primary Care.

    PubMed

    Isaac, Kathleen S; Hay, Jennifer L; Lubetkin, Erica I

    2016-06-01

    Addressing cultural competency in health care involves recognizing the diverse characteristics of the patient population and understanding how they impact patient care. Spirituality is an aspect of cultural identity that has become increasingly recognized for its potential to impact health behaviors and healthcare decision-making. We consider the complex relationship between spirituality and health, exploring the role of spirituality in primary care, and consider the inclusion of spirituality in existing models of health promotion. We discuss the feasibility of incorporating spirituality into clinical practice, offering suggestions for physicians. PMID:26832335

  17. Incorporation of additives into polymers

    DOEpatents

    McCleskey, T. Mark; Yates, Matthew Z.

    2003-07-29

    There has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.

  18. Reducing the cytotoxicity of inhalable engineered nanoparticles via in situ passivation with biocompatible materials.

    PubMed

    Byeon, Jeong Hoon; Park, Jae Hong; Peters, Thomas M; Roberts, Jeffrey T

    2015-07-15

    The cytotoxicity of model welding nanoparticles was modulated through in situ passivation with soluble biocompatible materials. A passivation process consisting of a spark discharge particle generator coupled to a collison atomizer as a co-flow or counter-flow configuration was used to incorporate the model nanoparticles with chitosan. The tested model welding nanoparticles are inhaled and that A549 cells are a human lung epithelial cell line. Measurements of in vitro cytotoxicity in A549 cells revealed that the passivated nanoparticles had a lower cytotoxicity (>65% in average cell viability, counter-flow) than the untreated model nanoparticles. Moreover, the co-flow incorporation between the nanoparticles and chitosan induced passivation of the nanoparticles, and the average cell viability increased by >80% compared to the model welding nanoparticles. As a more convenient way (additional chitosan generation and incorporation devices may not be required), other passivation strategies through a modification of the welding rod with chitosan adhesive and graphite paste did also enhance average cell viability (>58%). The approach outlined in this work is potentially generalizable as a new platform, using only biocompatible materials in situ, to treat nanoparticles before they are inhaled. PMID:25797930

  19. Efficacy of nanoparticles in achieving hemostasis

    NASA Astrophysics Data System (ADS)

    Schmitt, Carrie Catherine

    Uncontrollable hemorrhage is significant cause of preventable death in the military and civilian setting. Hemostatic wound dressings have been created in an attempt to rectify this problem, but none currently on the market are highly effective at controlling hemorrhage resulting in a need for an effective hemostatic wound dressing. This study investigated the effects of gold, silver, and silica nanoparticles on blood coagulation time in order to determine if nanoparticle incorporation into a hemostatic wound dressing would effectively achieve hemostasis. Gold, silver, and silica nanoparticles were experimented with two different ex vivo studies to determine their effects on coagulation. A modified Lee White Method and a rotational viscometer were utilized to assess the nanoparticles ability to clot blood. Results obtained from the modified Lee White Method proved inconsistent and inconclusive demonstrating a need for improved testing methods. Results acquired from viscometer testing demonstrated that silica was effective in decreasing coagulation time indicating its potential use as a hemostatic agent and its prospective incorporation into a hemostatic wound dressing.

  20. Piezoelectric Nanoparticle-Polymer Composite Materials

    NASA Astrophysics Data System (ADS)

    McCall, William Ray

    Herein we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be synthesized and fabricated into complex microstructures using sugar-templating methods or optical printing techniques. Stretchable foams with excellent tunable piezoelectric properties are created by incorporating sugar grains directly into polydimethylsiloxane (PDMS) mixtures containing barium titanate (BaTiO3 -- BTO) nanoparticles and carbon nanotubes (CNTs), followed by removal of the sugar after polymer curing. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio and the electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs. User defined 2D and 3D optically printed piezoelectric microstructures are also fabricated by incorporating BTO nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate (PEGDA) and exposing to digital optical masks that can be dynamically altered. Mechanical-to-electrical conversion efficiency of the optically printed composite is enhanced by chemically altering the surface of the BTO nanoparticles with acrylate groups which form direct covalent linkages with the polymer matrix under light exposure. Both of these novel materials should find exciting uses in a variety of applications including energy scavenging platforms, nano- and microelectromechanical systems (NEMS/MEMS), sensors, and acoustic actuators.

  1. Iron Nanoparticles in Reactive Environmental Barriers

    SciTech Connect

    Nuxoll, Eric E.; Shimotori, Tsutomu; Arnold, William A.; Cussler, Edward L.

    2003-09-23

    Zero-valent iron is cheap, environmentally innocuous, and effective at reducing chlorinated organics. It has, as a result, become a popular candidate for remediating aquifers contaminated with trichloroethylene and other halogenated pollutants. In this paper, we discuss one such system, where iron nanoparticles are synthesized and incorporated into polyvinyl alcohol membranes, forming water-permeable barriers to these pollutants. These barriers are tested against a variety of contaminants, including carbon tetrachloride, copper, and chromate.

  2. Photocurrent enhancements of organic solar cells by altering dewetting of plasmonic Ag nanoparticles

    PubMed Central

    Fleetham, Tyler; Choi, Jea-Young; Choi, Hyung Woo; Alford, Terry; Jeong, Doo Seok; Lee, Taek Sung; Lee, Wook Seong; Lee, Kyeong-Seok; Li, Jian; Kim, Inho

    2015-01-01

    Incorporation of metal nanoparticles into active layers of organic solar cells is one of the promising light trapping approaches. The size of metal nanoparticles is one of key factors to strong light trapping, and the size of thermally evaporated metal nanoparticles can be tuned by either post heat treatment or surface modification of substrates. We deposited Ag nanoparticles on ITO by varying nominal thicknesses, and post annealing was carried out to increase their size in radius. PEDOT:PSS was employed onto the ITO substrates as a buffer layer to alter the dewetting behavior of Ag nanoparticles. The size of Ag nanoparticles on PEDOT:PSS were dramatically increased by more than three times compared to those on the ITO substrates. Organic solar cells were fabricated on the ITO and PEDOT:PSS coated ITO substrates with incorporation of those Ag nanoparticles, and their performances were compared. The photocurrents of the cells with the active layers on PEDOT:PSS with an optimal choice of the Ag nanoparticles were greatly enhanced whereas the Ag nanoparticles on the ITO substrates did not lead to the photocurrent enhancements. The origin of the photocurrent enhancements with introducing the Ag nanoparticles on PEDOT:PSS are discussed. PMID:26388104

  3. Photocurrent enhancements of organic solar cells by altering dewetting of plasmonic Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Fleetham, Tyler; Choi, Jea-Young; Choi, Hyung Woo; Alford, Terry; Jeong, Doo Seok; Lee, Taek Sung; Lee, Wook Seong; Lee, Kyeong-Seok; Li, Jian; Kim, Inho

    2015-09-01

    Incorporation of metal nanoparticles into active layers of organic solar cells is one of the promising light trapping approaches. The size of metal nanoparticles is one of key factors to strong light trapping, and the size of thermally evaporated metal nanoparticles can be tuned by either post heat treatment or surface modification of substrates. We deposited Ag nanoparticles on ITO by varying nominal thicknesses, and post annealing was carried out to increase their size in radius. PEDOT:PSS was employed onto the ITO substrates as a buffer layer to alter the dewetting behavior of Ag nanoparticles. The size of Ag nanoparticles on PEDOT:PSS were dramatically increased by more than three times compared to those on the ITO substrates. Organic solar cells were fabricated on the ITO and PEDOT:PSS coated ITO substrates with incorporation of those Ag nanoparticles, and their performances were compared. The photocurrents of the cells with the active layers on PEDOT:PSS with an optimal choice of the Ag nanoparticles were greatly enhanced whereas the Ag nanoparticles on the ITO substrates did not lead to the photocurrent enhancements. The origin of the photocurrent enhancements with introducing the Ag nanoparticles on PEDOT:PSS are discussed.

  4. Toxicity of food-relevant nanoparticles in intestinal epithelial models

    NASA Astrophysics Data System (ADS)

    McCracken, Christie

    Nanoparticles are increasingly being incorporated into common consumer products, including in foods and food packaging, for their unique properties at the nanoscale. Food-grade silica and titania are used as anti-caking and whitening agents, respectively, and these particle size distributions are composed of approximately one-third nanoparticles. Zinc oxide and silver nanoparticles can be used for their antimicrobial properties. However, little is known about the interactions of nanoparticles in the body upon ingestion. This study was performed to investigate the role of nanoparticle characteristics including surface chemistry, dissolution, and material type on toxicity to the intestinal epithelium. Only mild acute toxicity of zinc oxide nanoparticles was observed after 24-hour treatment of intestinal epithelial C2BBe1 cells based on the results of toxicity assays measuring necrosis, apoptosis, membrane damage, and mitochondrial activity. Silica and titanium dioxide nanoparticles were not observed to be toxic although all nanoparticles were internalized by cells. In vitro digestion of nanoparticles in solutions representing the stomach and intestines prior to treatment of cells did not alter nanoparticle toxicity. Long-term repeated treatment of cells weekly for 24 hours with nanoparticles did not change nanoparticle cytotoxicity or the growth rate of the treated cell populations. Thus, silica, titanium dioxide, and zinc oxide nanoparticles were found to induce little toxicity in intestinal epithelial cells. Fluorescent silica nanoparticles were synthesized as a model for silica used in foods that could be tracked in vitro and in vivo. To maintain an exterior of pure silica, a silica shell was hydrolyzed around a core particle of quantum dots or a fluorescent dye electrostatically associated with a commercial silica particle. The quantum dots used were optimized from a previously reported microwave quantum dot synthesis to a quantum yield of 40%. Characterization of the silica particles showed that the surface properties resembled pure silica. These particles were able to be detected in vitro as well as in vivo after oral administration of nanoparticles to mice by gavage. After four daily administrations, nanoparticles were detected by fluorescence confocal microscopy in intestines as well as liver, kidney, spleen, lung, and brain. Thus, silica nanoparticles were able to traverse the intestinal epithelium. Further investigation is needed to determine nanoparticle accumulation and potential functional consequences throughout the body. Silver nanoparticles were particularly toxic to proliferating (subconfluent) C2BBe1 cells plated at low density, inducing 15% necrosis and a 76% decrease in mitochondrial activity. Silver nanoparticle treatment induced oxidative stress in cells based on increased GSH/GSSG ratios. In addition, silver nanoparticles induced G2/M phase cell cycle arrest and inhibited cell proliferation at doses forty times lower than those at which silica, titanium dioxide, and zinc oxide nanoparticles had inhibitory effects. Silver nanoparticles subjected to in vitro digestion before cell exposure required higher doses to induce toxicity, likely due to slower dissolution because of greater surface species adsorption. Silver nanoparticles did not cause toxicity or oxidative stress in confluent (stationary) cells. Thus, upon ingestion, silver nanoparticles may be especially toxic to proliferating stem cells in intestinal crypts, particularly in disease states with a compromised epithelium.

  5. Uranyl incorporation in natural calcite.

    SciTech Connect

    Kelly, S. D.; Newville, M. G.; Cheng, L.; Kemner, K. M.; Sutton, S. R.; Fenter, P.; Sturchio, N. C.; Spotl, C.; Environmental Research; Univ. of Chicago; Univ. of Illiois at Chicago; Univ. of Innsbruck

    2003-01-01

    The occurrence of trace amounts of uranyl in natural calcite has posed a long-standing problem in crystal chemistry because of speculation that the size and shape of the uranyl ion may preclude its incorporation in a stable lattice position in calcite. This also defines an important environmental problem because of its bearing on the transport and sequestration of uranyl released from nuclear facilities and uranium mining operations. Calcite is a nearly ubiquitous mineral in soils and groundwater aquifers. X-ray absorption spectroscopy and X-ray fluorescence microprobe studies of uranium in relatively U-rich {approx}13700-year-old calcite from a speleothem in northernmost Italy indicate substitution of uranyl for a calcium and two adjacent carbonate ions in calcite. These new data imply that uranyl has a stable lattice position in natural calcite, indicating that it may be reliably sequestered in calcite over long time scales.

  6. Electrostatic assembly of binary nanoparticle superlattices using protein cages

    NASA Astrophysics Data System (ADS)

    Kostiainen, Mauri A.; Hiekkataipale, Panu; Laiho, Ari; Lemieux, Vincent; Seitsonen, Jani; Ruokolainen, Janne; Ceci, Pierpaolo

    2013-01-01

    Binary nanoparticle superlattices are periodic nanostructures with lattice constants much shorter than the wavelength of light and could be used to prepare multifunctional metamaterials. Such superlattices are typically made from synthetic nanoparticles, and although biohybrid structures have been developed, incorporating biological building blocks into binary nanoparticle superlattices remains challenging. Protein-based nanocages provide a complex yet monodisperse and geometrically well-defined hollow cage that can be used to encapsulate different materials. Such protein cages have been used to program the self-assembly of encapsulated materials to form free-standing crystals and superlattices at interfaces or in solution. Here, we show that electrostatically patchy protein cages--cowpea chlorotic mottle virus and ferritin cages--can be used to direct the self-assembly of three-dimensional binary superlattices. The negatively charged cages can encapsulate RNA or superparamagnetic iron oxide nanoparticles, and the superlattices are formed through tunable electrostatic interactions with positively charged gold nanoparticles. Gold nanoparticles and viruses form an AB8fcc crystal structure that is not isostructural with any known atomic or molecular crystal structure and has previously been observed only with large colloidal polymer particles. Gold nanoparticles and empty or nanoparticle-loaded ferritin cages form an interpenetrating simple cubic AB structure (isostructural with CsCl). We also show that these magnetic assemblies provide contrast enhancement in magnetic resonance imaging.

  7. Synthesis and Characterization of Gold-Titanium Dioxide Nanoparticles

    NASA Astrophysics Data System (ADS)

    Cramer, Hailey; Shah, Ismat

    2013-03-01

    Nanoparticles are of recent scientific interest due to their unique size-dependent optical, electrical, and catalytic properties. Gold nanoparticles specifically, have many potential applications, especially in optoelectronic devices due to their optical properties and plasmon resonance. The specific goals of this research are to synthesize Au/TiO2 core-shell nanoparticles for their use in improving the overall efficiency of P3HT/PCBM polymer solar cells previously prepared in our lab. The standard sodium citrate reduction method was used to synthesize gold nanoparticles with an average diameter of 15 nm. Through changing the concentration of sodium citrate in solution we were able to tune the size of the nanoparticles, and therefore change their light-absorbing properties. The goals of this research are to cap the gold nanoparticles with TiO2 through a sol-gel method. Characterization of the Au/TiO2 particles will be performed using high resolution tunneling electron microscopy to determine the size of the nanoparticles and the thickness of the TiO2 shell. In addition, ultraviolet-visual spectroscopy was used to determine the absorption of the particles, and dynamic light scattering was used to confirm the size distribution of the particles. The incorporation of Au/TiO2 nanoparticles in P3HT/PCBM devices will be discussed.

  8. Functionalized mesoporous silica nanoparticles for oral delivery of budesonide

    SciTech Connect

    Yoncheva, K.; Popova, M.; Szegedi, A.; Mihaly, J.; Tzankov, B.; Lambov, N.; Konstantinov, S.; Tzankova, V.; Pessina, F.; Valoti, M.

    2014-03-15

    Non-functionalized and amino-functionalized mesoporous silica nanoparticle were loaded with anti-inflammatory drug budesonide and additionally post-coated with bioadhesive polymer (carbopol). TEM images showed spherical shape of the nanoparticles and slightly higher polydispersity after coating with carbopol. Nitrogen physisorption and thermogravimetic analysis revealed that more efficient loading and incorporation into the pores of nanoparticles was achieved with the amino-functionalized silica carrier. Infrared spectra indicated that the post-coating of these nanoparticles with carbopol led to the formation of bond between amino groups of the functionalized carrier and carboxyl groups of carbopol. The combination of amino-functionalization of the carrier with the post-coating of the nanoparticles sustained budesonide release. Further, an in vitro model of inflammatory bowel disease showed that the cytoprotective effect of budesonide loaded in the post-coated silica nanoparticles on damaged HT-29 cells was more pronounced compared to the cytoprotection obtained with pure budesonide. -- Graphical abstract: Silica mesoporous MCM-41 particles were amino-functionalized, loaded with budesonide and post-coated with bioadhesive polymer (carbopol) in order to achieve prolonged residence of anti-inflammatory drug in GIT. Highlights: • Higher drug loading in amino-functionalized mesoporous silica. • Amino-functionalization and post-coating of the nanoparticles sustained drug release. • Achievement of higher cytoprotective effect with drug loaded into the nanoparticles.

  9. Modified natural nanoparticles as contrast agents for medical imaging

    PubMed Central

    Cormode, David P.; Jarzyna, Peter A.; Mulder, Willem J. M.; Fayad, Zahi A.

    2009-01-01

    The development of novel and effective contrast agents is one of the drivers of the ongoing improvement in medical imaging. Many of the new agents reported are nanoparticle-based. There are a variety of natural nanoparticles known, e.g. lipoproteins, viruses or ferritin. Natural nanoparticles have advantages as delivery platforms such as biodegradability. In addition, our understanding of natural nanoparticles is quite advanced, allowing their adaptation as contrast agents. They can be labeled with small molecules or ions such as Gd3+ to act as contrast agents for magnetic resonance imaging, 18F to act as positron emission tomography contrast agents or fluorophores to act as contrast agents for fluorescence techniques. Additionally, inorganic nanoparticles such as iron oxide, gold nanoparticles or quantum dots can be incorporated to add further contrast functionality. Furthermore, these natural nanoparticle contrast agents can be rerouted from their natural targets via the attachment of targeting molecules. In this review, we discuss the various modified natural nanoparticles that have been exploited as contrast agents. PMID:19900496

  10. Anti-biofilm properties of wound dressing incorporating nonrelease polycationic antimicrobials.

    PubMed

    Atar-Froyman, Livnat; Sharon, Anat; Weiss, Ervin I; Houri-Haddad, Yael; Kesler-Shvero, Dana; Domb, Abraham J; Pilo, Raphael; Beyth, Nurit

    2015-04-01

    Polycationic nanoparticles show biocompatible, broad-spectrum bactericidal properties in vitro and in vivo when incorporated in denture lining material post-maxillectomy in head and neck cancer patients. In the present study, the synthesized Crosslinked quaternary ammonium polyethylenimine nanoparticles were found to have a strong bactericidal activity against a wide variety of microorganisms rapidly killing bacterial cells when incorporated at small concentrations into soft lining materials without compromising mechanical and biocompatibility properties. This appears advantageous over conventional released antimicrobials with regard to in vivo efficacy and safety, and may provide a convenient platform for the development of non-released antimicrobials. This is a crucial issue when it comes to giving an answer to the serious and life-threatening problems of contaminations in immunocompromised patients such as orofacial cancer patient. PMID:25678123

  11. Two-Phase Electrospinning to Incorporate Polyelectrolyte Complexes and Growth Factors into Electrospun Chitosan Nanofibers.

    PubMed

    Place, Laura W; Sekyi, Maria; Taussig, Julia; Kipper, Matt J

    2016-03-01

    Growth factors are potent signaling proteins for tissue engineering, but they are susceptible to loss of activity when exposed to solvents used for polymer processing. This work explores preservation of fibroblast growth factor-2 (FGF-2) activity in chitosan nanofibers using two-phase electrospinning via a compound coaxial needle and from a water-in-oil emulsion FGF-2 in aqueous poly(vinyl alcohol) is added on either the inside (A/O) or the outside (O/A) of an organic chitosan phase, using the compound needle. FGF-2 is further stabilized by complexation to heparin-based nanoparticles. The emulsion method does not result in detectable incorporation of FGF-2. The A/O fibers incorporate the highest amount of FGF-2. Nanoparticle-stabilized FGF-2 in A/O nanofibers is most active toward bone-marrow stromal cells. PMID:26611767

  12. Synthesis and applications of novel silver nanoparticle structures

    NASA Astrophysics Data System (ADS)

    Dukes, Kyle

    The field of nanotechnology is rapidly expanding across disciplines as each new development is realized. New exciting technologies are being driven by advances in the application of nanotechnology; including biochemical, optical, and semiconductors research. This thesis will focus on the use of silver nanoparticles as optical labels on cells, methods of forming different small structures of silver nanoparticles, as well as the use of silver nanoparticles in the development of a photovoltaic cell. Silver nanoparticles have been modified with self-assembled monolayers of hydroxyl-terminated long chain thiols and encapsulated with a silica shell. The resulting core-shell nanoparticles were used as optical labels for cell analysis using flow cytometry and microscopy. The excitation of plasmon resonances in nanoparticles results in strong depolarized scattering of visible light permitting detection at the single nanoparticle level. The nanoparticles were modified with neutravidin via epoxide-azide coupling chemistry and biotinylated antibodies targeting cell surface receptors were bound to the nanoparticle surface. The nanoparticle labels exhibited long-term stability under physiological conditions without aggregation or silver ion leaching. Labeled cells exhibited two orders of magnitude enhancement of the scattering intensity compared to unlabeled cells. Dimers of silver nanoparticles have been fabricated by first immobilizing a monolayer of single silver nanoparticles onto poly(4-vinylpyridine) covered glass slides. The monolayer was then exposed to adenine, which has two amines which will bind to silver. The nanoparticle monolayer, now modified with adenine, is exposed to a second suspension of nanoparticles which will bind with the amine modified monolayer. Finally, a thin silica shell is formed about the structure via solgel chemistry to prevent dissolution or aggregation upon sonication/striping. Circular arrays of silver nanoparticels are developed using a template base self assembly. A 1.5 micron silica sphere is bound to poly(4-vinylpyridine) coated glass and used as a template. a mask of silica monoxide is vacuum deposited atop the spheres/glass leaving a ring just below the sphere untouched and able to bind silver nanoparticles. Optical microscopy reveal interesting results under depolarized light conditions, but ultimate structural analysis has proven elusive. Semiconducting p-type cuprous oxide was electrochemically deposited on both silver and indium tin oxide electrodes. Silver nanoparticles were incorporated into the architecture either atop the cuprous oxide or sandwiched between cuprous oxide and n-type material. Increases in photocurrent were observed in both cases and further work must be conducted to optimize a solid state device for photovoltaic applications.

  13. Nanoparticles for transcutaneous vaccination.

    PubMed

    Hansen, Steffi; Lehr, Claus-Michael

    2012-03-01

    The living epidermis and dermis are rich in antigen presenting cells (APCs). Their activation can elicit a strong humoral and cellular immune response as well as mucosal immunity. Therefore, the skin is a very attractive site for vaccination, and an intradermal application of antigen may be much more effective than a subcutaneous or intramuscular injection. However, the stratum corneum (SC) is a most effective barrier against the invasion of topically applied vaccines. Products which have reached the stage of clinical testing, avoid this problem by injecting the nano-vaccine intradermally or by employing a barrier disrupting method and applying the vaccine to a relatively large skin area. Needle-free vaccination is desirable from a number of aspects: ease of application, improved patient acceptance and less risk of infection among them. Nanocarriers can be designed in a way that they can overcome the SC. Also incorporation into nanocarriers protects instable antigen from degradation, improves uptake and processing by APCs, and facilitates endosomal escape and nuclear delivery of DNA vaccines. In addition, sustained release systems may build a depot in the tissue gradually releasing antigen which may avoid booster doses. Therefore, nanoformulations of vaccines for transcutaneous immunization are currently a very dynamic field of research. Among the huge variety of nanocarrier systems that are investigated hopes lie on ultra-flexible liposomes, superfine rigid nanoparticles and nanocarriers, which are taken up by hair follicles. The potential and pitfalls associated with these three classes of carriers will be discussed. PMID:21854553

  14. Nanoparticles for transcutaneous vaccination

    PubMed Central

    Hansen, Steffi; Lehr, Claus‐Michael

    2012-01-01

    Summary The living epidermis and dermis are rich in antigen presenting cells (APCs). Their activation can elicit a strong humoral and cellular immune response as well as mucosal immunity. Therefore, the skin is a very attractive site for vaccination, and an intradermal application of antigen may be much more effective than a subcutaneous or intramuscular injection. However, the stratum corneum (SC) is a most effective barrier against the invasion of topically applied vaccines. Products which have reached the stage of clinical testing, avoid this problem by injecting the nano‐vaccine intradermally or by employing a barrier disrupting method and applying the vaccine to a relatively large skin area. Needle‐free vaccination is desirable from a number of aspects: ease of application, improved patient acceptance and less risk of infection among them. Nanocarriers can be designed in a way that they can overcome the SC. Also incorporation into nanocarriers protects instable antigen from degradation, improves uptake and processing by APCs, and facilitates endosomal escape and nuclear delivery of DNA vaccines. In addition, sustained release systems may build a depot in the tissue gradually releasing antigen which may avoid booster doses. Therefore, nanoformulations of vaccines for transcutaneous immunization are currently a very dynamic field of research. Among the huge variety of nanocarrier systems that are investigated hopes lie on ultra‐flexible liposomes, superfine rigid nanoparticles and nanocarriers, which are taken up by hair follicles. The potential and pitfalls associated with these three classes of carriers will be discussed. PMID:21854553

  15. On the thermal stability of volume holograms recorded in nanoparticle-polymer composite films

    NASA Astrophysics Data System (ADS)

    Tomita, Yasuo; Nakamura, Toshihiro; Tago, Atsushi

    2008-04-01

    We report on measurements of thermal expansion coefficients and temperature-dependent refractive indices of nanoparticle-polymer composite films in which plane-wave volume holograms are recorded. These physical constants are evaluated for photopolymer films with the incorporation of inorganic nanoparticles or binder polymer. We show that the incorporation of inorganic nanoparticles in photopolymer is a very effective method to suppress temperature-dependent film-thickness and refractive-index changes as well as to increase the refractive index modulation and reduce polymerization shrinkage.

  16. Finite Size Effects on the Real-Space Pair Distribution Function of Nanoparticles

    SciTech Connect

    Gilbert, Benjamin

    2008-10-01

    The pair distribution function (PDF) method is a powerful approach for the analysis of the structure of nanoparticles. An important approximation used in nanoparticle PDF simulations is the incorporation of a form factor describing nanoparticle size and shape. The precise effect of the form factor on the PDF is determined by both particle shape and structure if these characteristics are both anisotropic and correlated. The correct incorporation of finite size effects is important for distinguishing and quantifying the structural consequences of small particle size in nanomaterials.

  17. Cationic additives in nanosystems activate cytotoxicity and inflammatory response of human neutrophils: lipid nanoparticles versus polymeric nanoparticles

    PubMed Central

    Hwang, Tsong-Long; Aljuffali, Ibrahim A; Lin, Chwan-Fwu; Chang, Yuan-Ting; Fang, Jia-You

    2015-01-01

    This report compares the effect of lipid and polymeric nanoparticles upon human neutrophils in the presence of cationic surfactants. Nanostructured lipid carriers and poly(lactic-co-glycolic) acid nanoparticles were manufactured as lipid and polymeric systems, respectively. Some cytotoxic and proinflammatory mediators such as lactate dehydrogenase (LDH), elastase, O2•−, and intracellular Ca2+ were examined. The nanoparticles showed a size of 170–225 nm. Incorporation of cetyltrimethylammonium bromide or soyaethyl morpholinium ethosulfate, the cationic surfactant, converted zeta potential from a negative to a positive charge. Nanoparticles without cationic surfactants revealed a negligible change on immune and inflammatory responses. Cationic surfactants in both nanoparticulate and free forms induced cell death and the release of mediators. Lipid nanoparticles generally demonstrated a greater response compared to polymeric nanoparticles. The neutrophil morphology observed by electron microscopy confirmed this trend. Cetyltrimethylammonium bromide as the coating material showed more significant activation of neutrophils than soyaethyl morpholinium ethosulfate. Confocal microscope imaging displayed a limited internalization of nanoparticles into neutrophils. It is proposed that cationic nanoparticles interact with the cell membrane, triggering membrane disruption and the following Ca2+ influx. The elevation of intracellular Ca2+ induces degranulation and oxidative stress. The consequence of these effects is cytotoxicity and cell death. Caution should be taken when selecting feasible nanoparticulate formulations and cationic additives for consideration of applicability and toxicity. PMID:25609950

  18. Numeral Incorporation in Japanese Sign Language

    ERIC Educational Resources Information Center

    Ktejik, Mish

    2013-01-01

    This article explores the morphological process of numeral incorporation in Japanese Sign Language. Numeral incorporation is defined and the available research on numeral incorporation in signed language is discussed. The numeral signs in Japanese Sign Language are then introduced and followed by an explanation of the numeral morphemes which are…

  19. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Incorporated materials. 572.30 Section 572.30....30 Incorporated materials. (a) The drawings and specifications referred to in this regulation that... Federal Register has approved the materials incorporated by reference. For materials subject to...

  20. 49 CFR 587.5 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Incorporated materials. 587.5 Section 587.5... Barrier § 587.5 Incorporated materials. (a) The drawings and specifications referred to in this regulation that are not set forth in full are hereby incorporated in this part by reference. These materials...

  1. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Incorporated materials. 572.30 Section 572.30....30 Incorporated materials. (a) The drawings and specifications referred to in this regulation that... Federal Register has approved the materials incorporated by reference. For materials subject to...

  2. 49 CFR 587.5 - Incorporated materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Incorporated materials. 587.5 Section 587.5... Barrier § 587.5 Incorporated materials. (a) The drawings and specifications referred to in this regulation that are not set forth in full are hereby incorporated in this part by reference. These materials...

  3. 49 CFR 587.5 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Incorporated materials. 587.5 Section 587.5... Barrier § 587.5 Incorporated materials. (a) The drawings and specifications referred to in this regulation that are not set forth in full are hereby incorporated in this part by reference. These materials...

  4. 49 CFR 587.5 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Incorporated materials. 587.5 Section 587.5... Barrier § 587.5 Incorporated materials. (a) The drawings and specifications referred to in this regulation that are not set forth in full are hereby incorporated in this part by reference. These materials...

  5. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Incorporated materials. 572.30 Section 572.30....30 Incorporated materials. (a) The drawings and specifications referred to in this regulation that... Federal Register has approved the materials incorporated by reference. For materials subject to...

  6. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Incorporated materials. 572.30 Section 572.30....30 Incorporated materials. (a) The drawings and specifications referred to in this regulation that... Federal Register has approved the materials incorporated by reference. For materials subject to...

  7. Numeral Incorporation in Japanese Sign Language

    ERIC Educational Resources Information Center

    Ktejik, Mish

    2013-01-01

    This article explores the morphological process of numeral incorporation in Japanese Sign Language. Numeral incorporation is defined and the available research on numeral incorporation in signed language is discussed. The numeral signs in Japanese Sign Language are then introduced and followed by an explanation of the numeral morphemes which are

  8. SERRS coded nanoparticles for biomolecular labelling with wavelength-tunable discrimination.

    PubMed

    McKenzie, Fiona; Ingram, Andrew; Stokes, Robert; Graham, Duncan

    2009-03-01

    The preparation and use of tri-functional linkers for surface complexation to both gold and silver nanoparticles is reported. These molecules confer excellent stability towards nanoparticles ensuring particle monodispersity in biological buffers, and also incorporate dyes to allow use of the functionalised nanoparticles as SERRS reporters. Biomolecule conjugation and quantitation has been illustrated using Alexafluor 680 labelled streptavidin. Variation of the chromophore has been introduced, which allows for exquisite control of the SERRS by manipulation of laser wavelength. This demonstrates the potential of SERRS functionalised nanoparticles for multiple, simultaneous monitoring of excitation events, an area of research where the capability of molecular fluorophores and quantum dots is limited. PMID:19238293

  9. Synthesis, characterization and UV-shielding property of polystyrene-embedded CeO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Kang-Qiang; Kuang, Cheng-Xiu; Zhong, Ming-Qiang; Shi, Yan-Qin; Chen, Feng

    2013-10-01

    A cerium-triethanolamine (TEA) complex was prepared and used as the precursor to synthesize CeO2 nanoparticles. It was mixed with styrene (St) in aqueous solution and hydrolysized to generate CeO2 nanoparticles. In situ emulsion polymerization of the monomer was followed in one pot. The CeO2 nanoparticles were incorporated into polystyrene (PS) matrix and dispersed homogeneously, with an average crystallite size of 3-5 nm and a band gap at 3.01 eV. Meanwhile, the embedding of the CeO2 nanoparticles can enhance UV-shielding property of PS.

  10. Assessing Nanoparticle Toxicity

    NASA Astrophysics Data System (ADS)

    Love, Sara A.; Maurer-Jones, Melissa A.; Thompson, John W.; Lin, Yu-Shen; Haynes, Christy L.

    2012-07-01

    Nanoparticle toxicology, an emergent field, works toward establishing the hazard of nanoparticles, and therefore their potential risk, in light of the increased use and likelihood of exposure. Analytical chemists can provide an essential tool kit for the advancement of this field by exploiting expertise in sample complexity and preparation as well as method and technology development. Herein, we discuss experimental considerations for performing in vitro nanoparticle toxicity studies, with a focus on nanoparticle characterization, relevant model cell systems, and toxicity assay choices. Additionally, we present three case studies (of silver, titanium dioxide, and carbon nanotube toxicity) to highlight the important toxicological considerations of these commonly used nanoparticles.

  11. Cell tracking using nanoparticles.

    PubMed

    Vaccaro, Dennis E; Yang, Meiheng; Weinberg, James S; Reinhardt, Christopher P; Groman, Ernest V

    2008-09-01

    Tracking cells in regenerative medicine is becoming increasingly important for basic cell therapy science, for cell delivery optimization and for accurate biodistribution studies. This report describes nanoparticles that utilize stable-isotope metal labels for multiple detection technologies in preclinical studies. Cells labeled with nanoparticles can be imaged by electron microscopy, fluorescence, and magnetic resonance. The nanoparticle-labeled cells can be quantified by neutron activation, thereby allowing, with the use of standard curves, the determination of the number of labeled cells in tissue samples from in vivo sources. This report describes the characteristics of these nanoparticles and methods for using these nanoparticles to label and track cells. PMID:20559922

  12. Incorporation of Heparin into Biomaterials

    PubMed Central

    Sakiyama-Elbert, Shelly E

    2013-01-01

    This review provides an overview on the incorporation of heparin into biomaterials with a focus on drug delivery and the use of heparin-based biomaterials for self-assembly of polymer networks. Heparin conjugation to biomaterials was originally explored to reduce the thrombogenicity of materials in contact with blood. Many of the conjugation strategies that were developed for these applications are still popular today for other applications. More recently heparin has been conjugated to biomaterials for drug delivery applications. Many of the delivery approaches have taken advantage of the ability of heparin to bind to a wide variety of growth factors, protect them from degradation and to potentiate their interactions with cell surface receptors. More recently, the use of heparin as a base polymer for scaffold fabrication has also been explored, often utilizing non-covalent binding of heparin with peptides or proteins to promote self-assembly of hydrogel networks. This review will highlight recent advances in each of these areas. PMID:24021232

  13. Tailored Composite Polymer-Metal Nanoparticles by Miniemulsion Polymerization and Thiol-ene Functionalization

    PubMed Central

    van Berkel, Kim Y.

    2010-01-01

    A simple and modular synthetic approach, based on miniemulsion polymerization, has been developed for the fabrication of composite polymer-metal nanoparticle materials. The procedure produces well-defined composite structures consisting of gold, silver or MnFe2O4 nanoparticles (?10 nm in diameter) encapsulated within larger spherical nanoparticles of poly(divinylbenzene) (?100 nm in diameter). This methodology readily permits the incorporation of multiple metal domains into a single polymeric particle, while still preserving the useful optical and magnetic properties of the metal nanoparticles. The morphology of the composite particles is retained upon increasing the inorganic content, and also upon redispersion in organic solvents. Finally, the ability to tailor the surface chemistry of the composite nanoparticles and incorporate steric stabilizing groups using simple thiol-ene chemistry is demonstrated. PMID:20657708

  14. Peptide-directed self-assembly of functionalized polymeric nanoparticles part I: design and self-assembly of peptide-copolymer conjugates into nanoparticle fibers and 3D scaffolds.

    PubMed

    Ding, Xiaochu; Janjanam, Jagadeesh; Tiwari, Ashutosh; Thompson, Martin; Heiden, Patricia A

    2014-06-01

    A robust self-assembly of nanoparticles into fibers and 3D scaffolds is designed and fabricated by functionalizing a RAFT-polymerized amphiphilic triblock copolymer with designer ionic complementary peptides so that the assembled core-shell polymeric nanoparticles are directed by peptide assembly into continuous "nanoparticle fibers," ultimately leading to 3D fiber scaffolds. The assembled nanostructure is confirmed by FESEM and optical microscopy. The assembly is not hindered when a protein (insulin) is incorporated within the nanoparticles as an active ingredient. MTS cytotoxicity tests on SW-620 cell lines show that the peptides, copolymers, and peptide-copolymer conjugates are biocompatible. The methodology of self-assembled nanoparticle fibers and 3D scaffolds is intended to combine the advantages of a flexible hydrogel scaffold with the versatility of controlled release nanoparticles to offer unprecedented ability to incorporate desired drug(s) within a self-assembled scaffold system with individual control over the release of each drug. PMID:24610743

  15. Terminal supraparticle assemblies from similarly charged protein molecules and nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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 and bionic combination of properties as demonstrated by enzymatic nitrate reduction initiated by light absorption in the nanoparticle.

  16. 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

  17. Formulation and characterization of spray-dried powders containing nanoparticles for aerosol delivery to the lung.

    PubMed

    Sham, Jeffrey O-H; Zhang, Yu; Finlay, Warren H; Roa, Wilson H; Lbenberg, Raimar

    2004-01-28

    Spray-drying is a common practice of powder preparation for a wide range of drugs. Spray-dried powders can be used to deliver particles to the lungs via a dry powder inhaler (DPI). The present study investigated the feasibility of developing a platform for aerosol delivery of nanoparticles. Lactose was used as the excipient and spray-dried with two different types of nanoparticles: gelatin and polybutylcyanoacrylate nanoparticles. Results showed that some carrier particles were hollow while others had a continuous matrix. Gelatin nanoparticles were incorporated throughout the matrix and sometimes accumulated at one end of the lactose. Polycyanoacrylate nanoparticles mostly clustered in different spots within the lactose carriers. The mean sizes of both nanoparticle types were characterized at two different times: before they were spray-dried and after they were redissolved from the spray-dried powders. Both nanoparticle types remained in the nano-range size after spray-drying. The mean nanoparticle sizes were increased by approximately 30% after spray-drying, though this increase was statistically significant only for the gelatin nanoparticles. Dispersion of the powder with an in-house passive dry powder inhaler and subsequent cascade impaction measurements showed that incorporation of the nanoparticles did not affect the fine particle fraction (FPF) or mass median aerodynamic diameter (MMAD) of the powders. FPF was approximately 40% while MMAD was 3.0+/-0.2 microm, indicating the present formulations yield aerosols of a suitable particle size for efficient lung delivery of nanoparticles. The present work demonstrates that nanoparticles can be delivered to the lungs via carrier particles that dissolve after coming in contact with the aqueous environment of the lung epithelium. This opens the way for new drug-targeting strategies using nanoparticles for pulmonary delivery of drugs and diagnostics. PMID:14706257

  18. De-alloyed platinum nanoparticles

    DOEpatents

    Strasser, Peter; Koh, Shirlaine; Mani, Prasanna; Ratndeep, Srivastava

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  19. Solid Lipid Nanoparticles: A Modern Formulation Approach in Drug Delivery System

    PubMed Central

    Mukherjee, S.; Ray, S.; Thakur, R. S.

    2009-01-01

    Solid lipid nanoparticles are at the forefront of the rapidly developing field of nanotechnology with several potential applications in drug delivery, clinical medicine and research, as well as in other varied sciences. Due to their unique size-dependent properties, lipid nanoparticles offer the possibility to develop new therapeutics. The ability to incorporate drugs into nanocarriers offers a new prototype in drug delivery that could be used for secondary and tertiary levels of drug targeting. Hence, solid lipid nanoparticles hold great promise for reaching the goal of controlled and site specific drug delivery and hence have attracted wide attention of researchers. This review presents a broad treatment of solid lipid nanoparticles discussing their advantages, limitations and their possible remedies. The different types of nanocarriers which were based on solid lipid like solid lipid nanoparticles, nanostructured lipid carriers, lipid drug conjugates are discussed with their structural differences. Different production methods which are suitable for large scale production and applications of solid lipid nanoparticles are described. Appropriate analytical techniques for characterization of solid lipid nanoparticles like photon correlation spectroscopy, scanning electron microscopy, differential scanning calorimetry are highlighted. Aspects of solid lipid nanoparticles route of administration and their biodistribution are also incorporated. If appropriately investigated, solid lipid nanoparticles may open new vistas in therapy of complex diseases. PMID:20502539

  20. Amphotericin B aggregation inhibition with novel nanoparticles prepared with poly(epsilon-caprolactone)/poly(n,n-dimethylamino-2-ethyl methacrylate) diblock copolymer.

    PubMed

    Shim, Yong-Ho; Kim, You-Chan; Lee, Hong-Joo; Bougard, Francois; Dubois, Philippe; Choi, Ki-Choon; Chung, Chung-Wook; Kang, Dae Hwan; Jeong, Young-Il

    2011-01-01

    Diblock copolymers composed of poly(epsilon-caprolactone) (PCL) and poly(N,N-dimethylamino-2-ethyl methacrylate) (PDMAEMA), or methoxy polyethylene glycol(PEG), were synthesized via a combination of ring-opening polymerization and atom-transfer radical polymerization in order to prepare polymeric nanoparticles as an antifungal drug carrier. Amphotericin B (AmB), a natural antibiotic, was incorporated into the polymeric nanoparticles. The physical properties of AmB-incorporated polymeric nanoparticles with PCL-b-PDMAEMA and PCL-b-PEG were studied in relation to morphology and particle size. In the aggregation state study, AmB-incorporated PCL-b- PDMAEMA nanoparticles exhibited a monomeric state pattern of free AmB, whereas AmB-incorporated PCL-b- PEG nanoparticles displayed an aggregated pattern. In in vitro hemolysis tests with human red blood cells, AmBincorporated PCL-b-PDMAEMA nanoparticles were seen to be 10 times less cytotoxic than free AmB (5 microgram/ml). In addition, an improved antifungal activity of AmBincorporated polymeric nanoparticles was observed through antifungal activity tests using Candida albicans, whereas polymeric nanoparticles themselves were seen not to affect activity. Finally, in vitro AmB release studies were conducted, proving the potential of AmB-incorporated PCL-b-PDMAEMA nanoparticles as a new formulation candidate for AmB. PMID:21301189

  1. Targeted nanoparticle enhanced proapoptotic peptide as potential therapy for glioblastoma

    PubMed Central

    Agemy, Lilach; Friedmann-Morvinski, Dinorah; Kotamraju, Venkata Ramana; Roth, Lise; Sugahara, Kazuki N.; Girard, Olivier M.; Mattrey, Robert F.; Verma, Inder M.; Ruoslahti, Erkki

    2011-01-01

    Antiangiogenic therapy can produce transient tumor regression in glioblastoma (GBM), but no prolongation in patient survival has been achieved. We have constructed a nanosystem targeted to tumor vasculature that incorporates three elements: (i) a tumor-homing peptide that specifically delivers its payload to the mitochondria of tumor endothelial cells and tumor cells, (ii) conjugation of this homing peptide with a proapoptotic peptide that acts on mitochondria, and (iii) multivalent presentation on iron oxide nanoparticles, which enhances the proapoptotic activity. The iron oxide component of the nanoparticles enabled imaging of GBM tumors in mice. Systemic treatment of GBM-bearing mice with the nanoparticles eradicated most tumors in one GBM mouse model and significantly delayed tumor development in another. Coinjecting the nanoparticles with a tumor-penetrating peptide further enhanced the therapeutic effect. Both models used have proven completely resistant to other therapies, suggesting clinical potential of our nanosystem. PMID:21969599

  2. Labeling of macrophage cell using biocompatible magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Min, Ji Hyun; Kim, Sung Tae; Lee, Ji Sung; Kim, Kwanghee; Wu, Jun Hua; Jeong, Jaeho; Song, Ah Young; Lee, Kyung-Mi; Kim, Young Keun

    2011-04-01

    This work investigates the intrinsic cell labeling efficiency of the Fe3O4 nanoparticles prepared by a modified thermal decomposition method using nontoxic precursors and a biocompatible polymer surfactant. This method eliminates the current need for additional step of surface modification. The structural analysis reveals the highly crystalline feature of the nanoparticles, while the magnetic measurement shows their superparamagnetic behavior at room temperature. Fe3O4 nanoparticles were efficiently incorporated into the murine macrophage cells (RAW264.7) without visible cytotoxicity. Cell labeling efficiency was found to be over 90% as measured by magnetically activated cell sorting and physical property measurement system. Therefore, such Fe3O4 nanoparticles could provide a useful magnetic cell labeling tool for macrophage cells using their phagocytic/endocytic activity and further apply to the other relevant biomedical applications.

  3. Tuning ferromagnetism in zinc oxide nanoparticles by chromium doping

    NASA Astrophysics Data System (ADS)

    Kaur, Palvinder; Pandey, S. K.; Kumar, Sanjeev; Negi, N. S.; Chen, C. L.; Rao, S. M.; Wu, M. K.

    2015-11-01

    Zn1- x Cr x O nanoparticles with x = 0.0, 0.01, 0.03 and 0.05 were synthesized by the sol-gel technique. Powder X-ray diffraction (XRD) studies reveal that chromium (Cr) incorporates into the ZnO crystal lattice without disturbing the parent hexagonal (wurtzite) structure. Transmission electron microscopy (TEM) measurements show that the average size of these nanoparticles is in the range 15-25 nm. Optical absorption studies show that the band gap of ZnO nanoparticles varies with Cr doping. Photoluminescence (PL) studies depict the presence of defects in Cr-doped nanoparticles. Undoped ZnO exhibits diamagnetic behavior while Cr-doped ZnO samples exhibit weak ferromagnetism to anti-ferromagnetism depending on the Cr content.

  4. A simple method to ordered mesoporous carbons containing nickel nanoparticles

    SciTech Connect

    Dai, Sheng; Wang, Xiqing

    2009-01-01

    A series of ordered mesoporous carbons containing magnetic Ni nanoparticles (Ni-OMCs) with a variety of Ni loadings was made by a simple one-pot synthetic procedure through carbonization of phenolic resin-Pluronic block copolymer composites containing various amount of nickel nitrate. Such composite materials were characterized by N{sub 2} sorption, XRD, and STEM. Ni-OMCs exhibited high BET surface area, uniform pore size, and large pore volume without obvious pore blockage with a Ni loading as high as 15 wt%. Ni nanoparticles were crystalline with a face-center-cubic phase and observed mainly in the carbon matrix and on the outer surface as well. The average particle size of Ni nanoparticles was dependent on the preparation (carbonization) temperature and Ni loading; the higher the temperature was used and the more the Ni was incorporated, the larger the Ni nanoparticles were observed. One of the applications of Ni-OMCs was demonstrated as magnetically separable adsorbents.

  5. Spiropyran-based Photochromic Polymer Nanoparticles with Optically Switchable Luminescence

    PubMed Central

    Zhu, Ming-Qiang; Zhu, Linyong; Han, Jason J.; Wuwei, Wu; Hurst, James K.; Li, Alexander D. Q.

    2008-01-01

    Emulsion polymerization yields 40400 nm diameter polymer nanoparticles with spiropyran-merocyanine dyes incorporated into their hydrophobic cavities; in contrast to their virtually nonfluorescent character in most environments, the merocyanine forms of the encapsulated dyes are highly fluorescent. Spiro-mero photoisomerization is reversible, allowing the fluorescence to be switched on and off by alternating UV and visible light. Immobilizing the dye inside hydrophobic pockets of nanoparticles also improves its photostability, rendering it more resistant than the same dyes in solution to fatigue effects arising from photochemical switching. The photophysical characteristics of the encapsulated fluorophores differ dramatically from those of the same species in solution, making nanoparticle-protected hydrophobic fluorophores attractive materials for potential applications such as optical data storage and switching and biological fluorescent labeling. To evaluate the potential for biological tagging, these optically addressable nanoparticles have been delivered into living cells and imaged with a liquid nitrogen cooled CCD. PMID:16569006

  6. Green processing of metal oxide core-shell nanoparticles as low-temperature dielectrics in organic thin-film transistors.

    PubMed

    Portilla, Luis; Etschel, Sebastian H; Tykwinski, Rik R; Halik, Marcus

    2015-10-21

    TiO2 , Fe3 O4, AlOx , ITO (indium tin oxide), and CeO2 nanoparticles are tailored to exhibit excellent dispersability in deionized water and alcohols. The latter provides an ecofriendly solution for processing metal oxide nanoparticles at a neutral pH. Water-processed dielectrics from the metal oxide nanoparticles are incorporated into organic thin-film transistors fabricated on rigid and flexible substrates. PMID:26308740

  7. Nanoparticle ? -potentials.

    PubMed

    Doane, Tennyson L; Chuang, Chi-Hung; Hill, Reghan J; Burda, Clemens

    2012-03-20

    For over half a century, alternating electric fields have been used to induce particle transport, furnishing the ?-potential of analytes with sizes ranging from a few nanometers to several micrometers. Concurrent advances in nanotechnology have provided new materials for catalysis, self-assembly, and biomedical applications, all of which benefit from a thorough understanding of particle surface charge. Therefore, the measurement of the ?-potential via electrophoretic light scattering (ELS) has become essential for nanoparticle (NP) research. However, the interpretation of NP electrophoretic mobility, especially that of ligand-coated NPs, can be a complex undertaking. Despite the inherent intricacy of these data, key concepts from colloidal science can help to distill valuable information from ELS. In this Account, we adopt PEGylated Au NPs as an illustrative example to explore extensions of the classical theories of Smoluchowski, Hckel, and Henry to more contemporary theories for ligand-coated NP systems such as those from Ohshima, and Hill, Saville, and Russel. First, we review the basic experimental considerations necessary to understand NP electrophoretic mobility, identifying when O'Brien and White's numerical solution of the standard electrokinetic model should be adopted over Henry's closed-form analytical approximation. Next, we explore recent developments in the theory of ligand-coated particle electrophoresis, and how one can furnish accurate and meaningful relationships between measured NP mobility, ?-potential, and surface charge. By identifying key ligand-coated NP parameters (e.g., coating thickness, permeability, molecular mass, and hydrodynamic segment size), we present a systematic method for quantitatively interpreting NP electrophoretic mobility. In addition to reviewing theoretical foundations, we describe our recent results that examine how the unique surface curvature of NPs alters and controls their properties. These data provide guidelines that can expedite the rational design of NPs for advanced uses, such as heterogeneous catalysis and in vivo drug delivery. As a practical demonstration of these concepts, we apply the ligand-coated theory to a recently developed noncovalent PEGylated Au NP drug-delivery system. Our analysis suggests that anion adsorption on the Au NP core may enhance the stability of these NP-drug conjugates in solution. In addition to providing useful nanochemistry insights, the information in this Account will be useful to biomedical and materials engineers, who use ELS and ?-potentials for understanding NP dynamics. PMID:22074988

  8. Nanoparticles for Biomedical Imaging

    SciTech Connect

    Nune, Satish K.; Gunda, Padmaja; Thallapally, Praveen K.; Lin, Ying-Ying; Forrest, Laird M.; Berkland, Cory J.

    2009-11-01

    Background: Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 to 100 nm in diameter possess dimensions comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for early detection of diseases such as cancer. Surface functionalization has further expanded the potential of nanoparticles as probes for molecular imaging. Objective: To summarize emerging research of nanoparticles for biomedical imaging with increased selectivity and reduced non-specific uptake with increased spatial resolution containing stabilizers conjugated with targeting ligands. Methods: This review summarizes recent technological advances in the synthesis of various nanoparticle probes, and surveys methods to improve the targeting of nanoparticles for their applications in biomedical imaging. Conclusion: Structural design of nanomaterials for biomedical imaging continues to expand and diversify. Synthetic methods have aimed to control the size and surface characteristics of nanoparticles to control distribution, half-life and elimination. Although molecular imaging applications using nanoparticles are advancing into clinical applications, challenges such as storage stability and long-term toxicology should continue to be addressed. Keywords: nanoparticle synthesis, surface modification, targeting, molecular imaging, and biomedical imaging.

  9. Environmental Feedbacks and Engineered Nanoparticles: Mitigation of Silver Nanoparticle Toxicity to Chlamydomonas reinhardtii by Algal-Produced Organic Compounds

    PubMed Central

    Stevenson, Louise M.; Dickson, Helen; Klanjscek, Tin; Keller, Arturo A.; McCauley, Edward; Nisbet, Roger M.

    2013-01-01

    The vast majority of nanotoxicity studies measures the effect of exposure to a toxicant on an organism and ignores the potentially important effects of the organism on the toxicant. We investigated the effect of citrate-coated silver nanoparticles (AgNPs) on populations of the freshwater alga Chlamydomonas reinhardtii at different phases of batch culture growth and show that the AgNPs are most toxic to cultures in the early phases of growth. We offer strong evidence that reduced toxicity occurs because extracellular dissolved organic carbon (DOC) compounds produced by the algal cells themselves mitigate the toxicity of AgNPs. We analyzed this feedback with a dynamic model incorporating algal growth, nanoparticle dissolution, bioaccumulation of silver, DOC production and DOC-mediated inactivation of nanoparticles and ionic silver. Our findings demonstrate how the feedback between aquatic organisms and their environment may impact the toxicity and ecological effects of engineered nanoparticles. PMID:24086348

  10. Effect of nanoparticle size on the internal structure of copolymer-nanoparticles composite thin films studied by neutron reflection

    NASA Astrophysics Data System (ADS)

    Lauter-Pasyuk, V.; Lauter, H. J.; Ausserre, D.; Gallot, Y.; Cabuil, V.; Kornilov, E. I.; Hamdoun, B.

    1998-04-01

    Neutron reflection was used for the study of the composite films made of symmetric (d-PS-PBMA) diblock copolymer (molecular weight Mw=170 and 135 K) with nanoparticles of ?-Fe2O3 (4 and 6 nm in diameter) incorporated in the deuterated PS-domains with different concentrations. From the neutron reflection experiment we determined the period of the lamellar structure and the position of the nanoparticles in the PS-layers. It is important to examine the effect of the particle size on the lamellar structure. We determined that the small nanoparticles (4 nm) concentrate close to d-PS-PBMA interfaces while larger nanoparticles (6 nm) localize in the center of PS domains. This effect is of considerable interest in the elaboration of new composite materials since it will give a control on the particle distribution inside the host domains.

  11. Effect of nanoparticle size on the internal structure of copolymer-nanoparticles composite thin films studied by neutron reflection

    NASA Astrophysics Data System (ADS)

    Lauter-Pasyuk, V.; Lauter, H. J.; Ausserre, D.; Gallot, Y.; Cabuil, V.; Kornilov, E. I.; Hamdoun, B.

    Neutron reflection was used for the study of the composite films made of symmetric (d-PS-PBMA) diblock copolymer (molecular weight Mw = 170 and 135 K) with nanoparticles of ?-Fe 2O 3 (4 and 6 nm in diameter) incorporated in the deuterated PS-domains with different concentrations. From the neutron reflection experiment we determined the period of the lamellar structure and the position of the nanoparticles in the PS-layers. It is important to examine the effect of the particle size on the lamellar structure. We determined that the small nanoparticles (4 nm) concentrate close to d-PS-PBMA interfaces while larger nanoparticles (6 nm) localize in the center of PS domains. This effect is of considerable interest in the elaboration of new composite materials since it will give a control on the particle distribution inside the host domains.

  12. Nanoparticle-modified monolithic pipette tips for phosphopeptide enrichment.

    PubMed

    Krenkova, Jana; Foret, Frantisek

    2013-03-01

    We have developed nanoparticle-modified monoliths in pipette tips for selective and efficient enrichment of phosphopeptides. The 5 ?L monolithic beds were prepared by UV-initiated polymerization in 200 ?L polypropylene pipette tips and either iron oxide or hydroxyapatite nanoparticles were used for monolith modification. Iron oxide nanoparticles were prepared by a co-precipitation method and stabilized by citrate ions. A stable coating of iron oxide nanoparticles on the pore surface of the monolith was obtained via multivalent electrostatic interactions of citrate ions on the surface of nanoparticles with a quaternary amine functionalized poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) monolith. Hydroxyapatite nanoparticles were incorporated into the poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) monolith by simply admixing them in the polymerization mixture followed by in situ polymerization. The nanoparticle-modified monoliths were compared with commercially available titanium dioxide pipette tips. Performance of the developed and commercially available sorbents was demonstrated with the efficient and selective enrichment of phosphopeptides from peptide mixtures of ?-casein and ?-casein digests followed by off-line MALDI/MS analysis. PMID:22926133

  13. Multifunctional gold nanoparticles for diagnosis and therapy of disease

    PubMed Central

    Mieszawska, Aneta J.; Mulder, Willem J. M.; Fayad, Zahi A.

    2013-01-01

    Gold nanoparticles (AuNPs) have a number of physical properties that make them appealing for medical applications. For example, the attenuation of X-rays by gold nanoparticles has led to their use in computed tomography imaging and as adjuvants for radiotherapy. AuNPs have numerous other applications in imaging, therapy and diagnostic systems. The advanced state of synthetic chemistry of gold nanoparticles offers precise control over physicochemical and optical properties. Furthermore gold cores are inert and are considered to be biocompatible and non-toxic. The surface of gold nanoparticles can easily be modified for a specific application and ligands for targeting, drugs or biocompatible coatings can be introduced. AuNPs can be incorporated into larger structures such as polymeric nanoparticles or liposomes that deliver large payloads for enhanced diagnostic applications, efficiently encapsulate drugs for concurrent therapy or add additional imaging labels. This array of features has led to the afore-mentioned applications in biomedical fields, but more recently in approaches where multifunctional gold nanoparticles are used for multiple methods, such as concurrent diagnosis and therapy, so called theranostics. The following review covers basic principles and recent findings in gold nanoparticle applications for imaging, therapy and diagnostics, with a focus on reports of multifunctional AuNPs. PMID:23360440

  14. Dissolution-accompanied aggregation kinetics of silver nanoparticles.

    PubMed

    Li, Xuan; Lenhart, John J; Walker, Harold W

    2010-11-16

    Bare silver nanoparticles with diameters of 82 1.3 nm were synthesized by the reduction of the Ag(NH(3))(2)(+) complex with D-maltose, and their morphology, crystalline structure, UV-vis spectrum, and electrophoretic mobilities were determined. Dynamic light scattering was employed to assess early stage aggregation kinetics by measuring the change in the average hydrodynamic diameter of the nanoparticles with time over a range of electrolyte types (NaCl, NaNO(3), and CaCl(2)) and concentrations. From this the critical coagulation concentration values were identified as 30, 40, and 2 mM for NaNO(3), NaCl, and CaCl(2), respectively. Although the silver nanoparticles were observed to dissolve in all three electrolyte solutions, the aggregation results were still consistent with classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The dissolution of the silver nanoparticles, which were coated with a layer of Ag(2)O, was highly dependent on the electrolyte type and concentration. In systems with Cl(-) a secondary precipitate, likely AgCl, also formed and produced a coating layer that incorporated the silver nanoparticles. Aggregation of the silver nanoparticles was also examined in the presence of Nordic aquatic fulvic acid and was little changed compared to that evaluated under identical fulvic acid-free conditions. These results provide a fundamental basis for further studies evaluating the environmental fate of silver nanoparticles in natural aquatic systems. PMID:20879768

  15. Photodynamic characterization and optimization using multifunctional nanoparticles for brain cancer treatment

    NASA Astrophysics Data System (ADS)

    Herrmann, Kristen; Lee Koo, Yong-Eun; Orringer, Daniel A.; Sagher, Oren; Philbert, Martin; Kopelman, Raoul

    2013-03-01

    Photosensitizer-conjugated polyacrylamide nanoparticles were prepared for in vivo characterization of the minimally invasive and localized treatment of photodynamic therapy (PDT) on brain tumors. By incorporating a variety of nanoparticle matrixes, choosing methylene blue as a photosensitizer, and targeting the nanoparticle by the use of F3 peptide we have made nanoparticle-based PDT improvements to current PDT efficiency. Quantitative growth patterns were determined through visual observation of the tumorigenic response to various treatments by the use of an animal cranial window model. PDT treatments with methylene blue-polyacrylamide (MB-PAA) nanoparticles produced significant adjournment of tumor growth over control groups, clearly demonstrating the advantages of nanoparticle-based PDT agents for the eradication of local tumors, leading to the potential palliation of the advancing disease.

  16. Molecular dynamics study of nanoparticle stability at liquid interfaces: Effect of nanoparticle-solvent interaction and capillary waves

    NASA Astrophysics Data System (ADS)

    Cheung, David L.

    2011-08-01

    While the interaction of colloidal particles (sizes in excess of 100 nm) with liquid interfaces may be understood in terms of continuum models, which are grounded in macroscopic properties such as surface and line tensions, the behaviour of nanoparticles at liquid interfaces may be more complex. Recent simulations [D. L. Cheung and S. A. F. Bon, Phys. Rev. Lett. 102, 066103 (2009)], 10.1103/PhysRevLett.102.066103 of nanoparticles at an idealised liquid-liquid interface showed that the nanoparticle-interface interaction range was larger than expected due, in part, to the action of thermal capillary waves. In this paper, molecular dynamics simulations of a Lennard-Jones nanoparticle in a binary Lennard-Jones mixture are used to confirm that these previous results hold for more realistic models. Furthermore by including attractive interactions between the nanoparticle and the solvent, it is found that the detachment energy decreases as the nanoparticle-solvent attraction increases. Comparison between the simulation results and recent theoretical predictions [H. Lehle and M. Oettel, J. Phys. Condens. Matter 20, 404224 (2008)], 10.1088/0953-8984/20/40/404224 shows that for small particles the incorporation of capillary waves into the predicted effective nanoparticle-interface interaction improves agreement between simulation and theory.

  17. Silica nanoparticles for micro-particle imaging velocimetry: fluorosurfactant improves nanoparticle stability and brightness of immobilized iridium(III) complexes.

    PubMed

    Lewis, David J; Dore, Valentina; Rogers, Nicola J; Mole, Thomas K; Nash, Gerard B; Angeli, Panagiota; Pikramenou, Zoe

    2013-11-26

    To establish highly luminescent nanoparticles for monitoring fluid flows, we examined the preparation of silica nanoparticles based on immobilization of a cyclometalated iridium(III) complex and an examination of the photophysical studies provided a good insight into the Ir(III) microenvironment in order to reveal the most suitable silica nanoparticles for micro particle imaging velocimetry (?-PIV) studies. Iridium complexes covalently incorporated at the surface of preformed silica nanoparticles, [Ir-4]@Si500-Z, using a fluorinated polymer during their preparation, demonstrated better stability than those without the polymer, [Ir-4]@Si500, as well as an increase in steady state photoluminescence intensity (and therefore particle brightness) and lifetimes which are increased by 7-fold compared with nanoparticles with the same metal complex attached covalently throughout their core, [Ir-4]?Si500. Screening of the nanoparticles in fluid flows using epi-luminescence microscopy also confirm that the brightest, and therefore most suitable particles for microparticle imaging velocimetry (?-PIV) measurements are those with the Ir(III) complex immobilized at the surface with fluorosurfactant, that is [Ir-4]@Si500-Z. ?-PIV studies demonstrate the suitability of these nanoparticles as nanotracers in microchannels. PMID:24164285

  18. Aptamer conjugated magnetic nanoparticles as nanosurgeons

    NASA Astrophysics Data System (ADS)

    Nair, Baiju G.; Nagaoka, Yutaka; Morimoto, Hisao; Yoshida, Yasuhiko; Maekawa, Toru; Sakthi Kumar, D.

    2010-11-01

    Magnetic nanoparticles have shown promise in the fields of targeted drug delivery, hyperthermia and magnetic resonance imaging (MRI) in cancer therapy. The ability of magnetic nanoparticles to undergo surface modification and the effect of external magnetic field in the dynamics of their movement make them an excellent nanoplatform for cancer destruction. Surgical removal of cancerous or unwanted cells selectively from the interior of an organ or tissue without any collateral damage is a serious problem due to the highly infiltrative nature of cancer. To address this problem in surgery, we have developed a nanosurgeon for the selective removal of target cells using aptamer conjugated magnetic nanoparticles controlled by an externally applied three-dimensional rotational magnetic field. With the help of the nanosurgeon, we were able to perform surgical actions on target cells in in vitro studies. LDH and intracellular calcium release assay confirmed the death of cancer cells due to the action of the nanosurgeon which in turn nullifies the possibility of proliferation by the removed cells. The nanosurgeon will be a useful tool in the medical field for selective surgery and cell manipulation studies. Additionally, this system could be upgraded for the selective removal of complex cancers from diverse tissues by incorporating various target specific ligands on magnetic nanoparticles.

  19. Aptamer conjugated magnetic nanoparticles as nanosurgeons.

    PubMed

    Nair, Baiju G; Nagaoka, Yutaka; Morimoto, Hisao; Yoshida, Yasuhiko; Maekawa, Toru; Kumar, D Sakthi

    2010-11-12

    Magnetic nanoparticles have shown promise in the fields of targeted drug delivery, hyperthermia and magnetic resonance imaging (MRI) in cancer therapy. The ability of magnetic nanoparticles to undergo surface modification and the effect of external magnetic field in the dynamics of their movement make them an excellent nanoplatform for cancer destruction. Surgical removal of cancerous or unwanted cells selectively from the interior of an organ or tissue without any collateral damage is a serious problem due to the highly infiltrative nature of cancer. To address this problem in surgery, we have developed a nanosurgeon for the selective removal of target cells using aptamer conjugated magnetic nanoparticles controlled by an externally applied three-dimensional rotational magnetic field. With the help of the nanosurgeon, we were able to perform surgical actions on target cells in in vitro studies. LDH and intracellular calcium release assay confirmed the death of cancer cells due to the action of the nanosurgeon which in turn nullifies the possibility of proliferation by the removed cells. The nanosurgeon will be a useful tool in the medical field for selective surgery and cell manipulation studies. Additionally, this system could be upgraded for the selective removal of complex cancers from diverse tissues by incorporating various target specific ligands on magnetic nanoparticles. PMID:20947949

  20. Stimulus responsive nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darren Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2013-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  1. Stimulus Responsive Nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darran Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2015-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  2. Cytotoxicity of gold nanoparticles.

    PubMed

    Pan, Yu; Bartneck, Matthias; Jahnen-Dechent, Willi

    2012-01-01

    Nanomaterials are now routinely used in technical as well as medical applications. The very physicochemical properties that favor nanomaterial application are the prime cause that these materials cannot be considered "generally safe." We are still far from predicting the toxicological profile of new nanoparticles, despite continuous attempts to establish a structure-function relation between the physical and chemical properties of nanoparticles and their interactions with biological systems. Herein, we summarize some basic concept to assess nanoparticle toxicity, death pathways, cell cycle, and oxidative stress in response to nanoparticle exposure of cells. PMID:22568908

  3. Nanoparticles for biomedical imaging

    PubMed Central

    Nune, Satish K; Gunda, Padmaja; Thallapally, Praveen K; Lin, Ying-Ying; Forrest, M Laird; Berkland, Cory J

    2011-01-01

    Background Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 – 100 nm in diameter have dimensions comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for early detection of diseases such as cancer. Surface functionalization has expanded further the potential of nanoparticles as probes for molecular imaging. Objective To summarize emerging research of nanoparticles for biomedical imaging with increased selectivity and reduced nonspecific uptake with increased spatial resolution containing stabilizers conjugated with targeting ligands. Methods This review summarizes recent technological advances in the synthesis of various nanoparticle probes, and surveys methods to improve the targeting of nanoparticles for their application in biomedical imaging. Conclusion Structural design of nanomaterials for biomedical imaging continues to expand and diversify. Synthetic methods have aimed to control the size and surface characteristics of nanoparticles to control distribution, half-life and elimination. Although molecular imaging applications using nanoparticles are advancing into clinical applications, challenges such as storage stability and long-term toxicology should continue to be addressed. PMID:19743894

  4. Fabrication of three-dimensionally interconnected nanoparticle superlattices and their lithium-ion storage properties

    PubMed Central

    Jiao, Yucong; Han, Dandan; Ding, Yi; Zhang, Xianfeng; Guo, Guannan; Hu, Jianhua; Yang, Dong; Dong, Angang

    2015-01-01

    Three-dimensional superlattices consisting of nanoparticles represent a new class of condensed materials with collective properties arising from coupling interactions between close-packed nanoparticles. Despite recent advances in self-assembly of nanoparticle superlattices, the constituent materials have been limited to those that are attainable as monodisperse nanoparticles. In addition, self-assembled nanoparticle superlattices are generally weakly coupled due to the surface-coating ligands. Here we report the fabrication of three-dimensionally interconnected nanoparticle superlattices with face-centered cubic symmetry without the presynthesis of the constituent nanoparticles. We show that mesoporous carbon frameworks derived from self-assembled supercrystals can be used as a robust matrix for the growth of nanoparticle superlattices with diverse compositions. The resulting interconnected nanoparticle superlattices embedded in a carbon matrix are particularly suitable for energy storage applications. We demonstrate this by incorporating tin oxide nanoparticle superlattices as anode materials for lithium-ion batteries, and the resulting electrochemical performance is attributable to their unique architectures. PMID:25739732

  5. Field emission scanning electron microscopy (FE-SEM) as an approach for nanoparticle detection inside cells.

    PubMed

    Havrdova, M; Polakova, K; Skopalik, J; Vujtek, M; Mokdad, A; Homolkova, M; Tucek, J; Nebesarova, J; Zboril, R

    2014-12-01

    When developing new nanoparticles for bio-applications, it is important to fully characterize the nanoparticle's behavior in biological systems. The most common techniques employed for mapping nanoparticles inside cells include transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). These techniques entail passing an electron beam through a thin specimen. STEM or TEM imaging is often used for the detection of nanoparticles inside cellular organelles. However, lengthy sample preparation is required (i.e., fixation, dehydration, drying, resin embedding, and cutting). In the present work, a new matrix (FTO glass) for biological samples was used and characterized by field emission scanning electron microscopy (FE-SEM) to generate images comparable to those obtained by TEM. Using FE-SEM, nanoparticle images were acquired inside endo/lysosomes without disruption of the cellular shape. Furthermore, the initial steps of nanoparticle incorporation into the cells were captured. In addition, the conductive FTO glass endowed the sample with high stability under the required accelerating voltage. Owing to these features of the sample, further analyses could be performed (material contrast and energy-dispersive X-ray spectroscopy (EDS)), which confirmed the presence of nanoparticles inside the cells. The results showed that FE-SEM can enable detailed characterization of nanoparticles in endosomes without the need for contrast staining or metal coating of the sample. Images showing the intracellular distribution of nanoparticles together with cellular morphology can give important information on the biocompatibility and demonstrate the potential of nanoparticle utilization in medicine. PMID:25173605

  6. In-situ dispersion and optical manipulation of magnetic carbon nanoparticles

    NASA Astrophysics Data System (ADS)

    Gusain, Sunil; Mohanty, Samarendra; Koymen, Ali

    2009-10-01

    Magnetic carbon nanoparticles are finding increasing use in enhancing contrast of imaging and photo thermal therapy of cancer. However, conventional synthesis of these nanoparticles involves very cumbersome and skillful interventions. We developed a simple method for controlled synthesis of amorphous carbon nanoparticles using dense medium plasma generated in the cavitation field of an ultrasonic horn in Benzene using two metal electrodes. In this method, the electrode (magnetic) material is incorporated into the C nanoparticles, as confirmed by hysteresis curve, measured using SQUID magnetometer. TEM images showed that the size of the C nanoparticles is in the range of 8-14 nm and the electron diffraction established that these nanoparticles are amorphous. The absorption spectrum in near-IR region was measured to be of similar value as in the visible region, making it a very useful candidate for photothermal therapy using near-infrared laser in the biological window. These carbon nanoparticles aggregates and tend to form clusters. For in-situ dispersion of these nanoparticles, we made use of the absorption property of these nanoparticles using a focused near-IR cw laser microbeam (1064nm). We believe the magnetic property of these nanoparticles would allow effective localization in the tumor region by application of external magnetic field.

  7. Enhancement of the near-band-edge photoluminescence of ZnO nanowires: Important role of hydrogen incorporation versus plasmon resonances

    SciTech Connect

    Dev, A.; Richters, J. P.; Gutowski, J.; Voss, T.; Sartor, J.; Kalt, H.

    2011-03-28

    We investigated the photoluminescence properties of ZnO nanowires coated with Au, Ag, and Pt nanoparticles deposited by dc sputtering. A strong enhancement of the near-band-edge emission was observed in all metal-coated samples but also if the samples were treated with Ar plasma without any nanoparticle deposition. High-resolution photoluminescence spectroscopy revealed hydrogen-donor-bound-exciton emission in all samples indicating unintentional hydrogen incorporation. A shorter decay time of the near-band-edge emission was observed in all cases. The results indicate that unintentional hydrogen incorporation plays a dominant role when metal deposition is performed by sputtering.

  8. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES ES-2re Side Impact Crash... 50th Percentile Adult Male Side Impact Crash Test Dummy, February 2008,” incorporated by reference...

  9. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES ES-2re Side Impact Crash... 50th Percentile Adult Male Side Impact Crash Test Dummy, February 2008,” incorporated by reference...

  10. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES 2re Side Impact Crash Test... 50th Percentile Adult Male Side Impact Crash Test Dummy, February 2008,” incorporated by reference...

  11. Incorporating Sociology into Community Service Classes

    ERIC Educational Resources Information Center

    Hochschild, Thomas R., Jr.; Farley, Matthew; Chee, Vanessa

    2014-01-01

    Sociologists and instructors who teach about community service share an affinity for understanding and addressing social problems. While many studies have demonstrated the benefits of incorporating community service into sociology courses, we examine the benefits of incorporating sociological content into community service classes. The authors…

  12. Incorporating Sociology into Community Service Classes

    ERIC Educational Resources Information Center

    Hochschild, Thomas R., Jr.; Farley, Matthew; Chee, Vanessa

    2014-01-01

    Sociologists and instructors who teach about community service share an affinity for understanding and addressing social problems. While many studies have demonstrated the benefits of incorporating community service into sociology courses, we examine the benefits of incorporating sociological content into community service classes. The authors

  13. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Incorporated materials. 572.40 Section 572.40... Percentile Male § 572.40 Incorporated materials. (a) The drawings, specifications, manual, and computer... by reference. These materials are thereby made part of this regulation. The Director of the...

  14. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Incorporated materials. 572.40 Section 572.40... Percentile Male § 572.40 Incorporated materials. (a) The drawings, specifications, manual, and computer... by reference. These materials are thereby made part of this regulation. The Director of the...

  15. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Incorporated materials. 572.40 Section 572.40... Percentile Male § 572.40 Incorporated materials. (a) The drawings, specifications, manual, and computer... by reference. These materials are thereby made part of this regulation. The Director of the...

  16. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Incorporated materials. 572.40 Section 572.40... Percentile Male § 572.40 Incorporated materials. (a) The drawings, specifications, manual, and computer... by reference. These materials are thereby made part of this regulation. The Director of the...

  17. Constraints on Noun Incorporation in Korean.

    ERIC Educational Resources Information Center

    Khym, Hangyoo

    1997-01-01

    A study of the noun incorporation phenomenon in Korean suggests that noun incorporation occurs at D-structure and obeys the Head Movement Constraint syntactically, and the Theme-Only Constraint semantically. First, the structure of "sunrise"-type words is identified, showing that before derivation through nominalization of the affix "-i,"…

  18. Epidermal growth factor receptor-targeted lipid nanoparticles retain self-assembled nanostructures and provide high specificity

    NASA Astrophysics Data System (ADS)

    Zhai, Jiali; Scoble, Judith A.; Li, Nan; Lovrecz, George; Waddington, Lynne J.; Tran, Nhiem; Muir, Benjamin W.; Coia, Gregory; Kirby, Nigel; Drummond, Calum J.; Mulet, Xavier

    2015-02-01

    Next generation drug delivery utilising nanoparticles incorporates active targeting to specific sites. In this work, we combined targeting with the inherent advantages of self-assembled lipid nanoparticles containing internal nano-structures. Epidermal growth factor receptor (EGFR)-targeting, PEGylated lipid nanoparticles using phytantriol and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-PEG-maleimide amphiphiles were created. The self-assembled lipid nanoparticles presented here have internal lyotropic liquid crystalline nano-structures, verified by synchrotron small angle X-ray scattering and cryo-transmission electron microscopy, that offer the potential of high drug loading and enhanced cell penetration. Anti-EGFR Fab' fragments were conjugated to the surface of nanoparticles via a maleimide-thiol reaction at a high conjugation efficiency and retained specificity following conjugation to the nanoparticles. The conjugated nanoparticles were demonstrated to have high affinity for an EGFR target in a ligand binding assay.Next generation drug delivery utilising nanoparticles incorporates active targeting to specific sites. In this work, we combined targeting with the inherent advantages of self-assembled lipid nanoparticles containing internal nano-structures. Epidermal growth factor receptor (EGFR)-targeting, PEGylated lipid nanoparticles using phytantriol and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-PEG-maleimide amphiphiles were created. The self-assembled lipid nanoparticles presented here have internal lyotropic liquid crystalline nano-structures, verified by synchrotron small angle X-ray scattering and cryo-transmission electron microscopy, that offer the potential of high drug loading and enhanced cell penetration. Anti-EGFR Fab' fragments were conjugated to the surface of nanoparticles via a maleimide-thiol reaction at a high conjugation efficiency and retained specificity following conjugation to the nanoparticles. The conjugated nanoparticles were demonstrated to have high affinity for an EGFR target in a ligand binding assay. Electronic supplementary information (ESI) available: Fig. S1-S4. See DOI: 10.1039/c4nr05200e

  19. Latex nanoparticles for multimodal imaging and detection in vivo

    NASA Astrophysics Data System (ADS)

    Cartier, R.; Kaufner, L.; Paulke, B. R.; Wüstneck, R.; Pietschmann, S.; Michel, R.; Bruhn, H.; Pison, U.

    2007-05-01

    The aim of the present work was to develop a multimodal imaging and detection approach to study the behaviour of nanoparticles in animal studies. Highly carboxylated 144 nm-sized latex nanoparticles were labelled with 68Ga for positron emission tomography, 111In for quantitative gamma scintigraphy or Gd3+ for magnetic resonance imaging. Following intravenous injection into rats, precise localization was achieved revealing the tracer in the blood compartment with a time-dependent accumulation in the liver. In addition, rhodamine B was also incorporated to examine specific interactions with blood cells. Flow cytometry and fluorescent microscopy show uptake of nanoparticles by leucocytes and, unexpectedly, thrombocytes, but not erythrocytes. Cellular internalization was an active and selective process. Further incorporation of polyethylene glycol into the nanoparticle corona could prevent uptake by thrombocytes but not macrophages or monocytes. Our data demonstrate the feasibility of a multimodal approach and its usefulness to analyse the fate of nanoparticles at the macroscopic and cellular level. It will facilitate the development of functionalized nanocarrier systems and extend their biomedical applications.

  20. Dispersion of TiO? nanoparticle agglomerates by Pseudomonas aeruginosa.

    PubMed

    Horst, Allison M; Neal, Andrea C; Mielke, Randall E; Sislian, Patrick R; Suh, Won Hyuk; Mdler, Lutz; Stucky, Galen D; Holden, Patricia A

    2010-11-01

    Engineered nanoparticles are increasingly incorporated into consumer products and are emerging as potential environmental contaminants. Upon environmental release, nanoparticles could inhibit bacterial processes, as evidenced by laboratory studies. Less is known regarding bacterial alteration of nanoparticles, including whether bacteria affect physical agglomeration states controlling nanoparticle settling and bioavailability. Here, the effects of an environmental strain of Pseudomonas aeruginosa on TiO? nanoparticle agglomerates formed in aqueous media are described. Environmental scanning electron microscopy and cryogenic scanning electron microscopy visually demonstrated bacterial dispersion of large agglomerates formed in cell culture medium and in marsh water. For experiments in cell culture medium, quantitative image analysis verified that the degrees of conversion of large agglomerates into small nanoparticle-cell combinations were similar for 12-h-growth and short-term cell contact experiments. Dispersion in cell growth medium was further characterized by size fractionation: for agglomerated TiO? suspensions in the absence of cells, 81% by mass was retained on a 5-?m-pore-size filter, compared to only 24% retained for biotic treatments. Filtrate cell and agglomerate sizes were characterized by dynamic light scattering, revealing that the average bacterial cell size increased from 1.4 ?m to 1.9 ?m because of nano-TiO? biosorption. High-magnification scanning electron micrographs showed that P. aeruginosa dispersed TiO? agglomerates by preferential biosorption of nanoparticles onto cell surfaces. These results suggest a novel role for bacteria in the environmental transport of engineered nanoparticles, i.e., growth-independent, bacterially mediated size and mass alterations of TiO? nanoparticle agglomerates. PMID:20851981

  1. Biocompatible nanoparticles and biopolyelectrolytes

    NASA Astrophysics Data System (ADS)

    Zribi, Olena

    The research presented in this manuscript encompasses a merger of two research directions: a study of aqueous nanoparticle colloids and a study of biological polyelectrolytes. The majority of biomedical applications of nanoparticles require stable aqueous colloids of nanoparticles as a starting point. A new one-step method of preparation of aqueous solutions of ultra-fine ferroelectric barium titanate nanoparticles was developed and generalized to the preparation of stable aqueous colloids of semiconductor nanoparticles. This high-energy ball milling technique is low cost, environmentally friendly, and allows for control of nanoparticle size by changing milling time. Aqueous colloids of BaTiO3 nanoparticles are stable over time, maintain ferroelectricity and can be used as second harmonic generating nanoprobes for biomedical imaging. Biopolyelectrolytes exhibit a variety of novel liquid-crystalline phases in aqueous solutions where their electrolytic nature is a driving force behind phase formation. We study medically relevant mixtures of F-actin, DNA and oppositely charged ions (such as multivalent salts and antibiotic drugs) and map out phase diagrams and laws that govern phase transitions. We combine these research directions in studies of the condensation behavior in aqueous solutions of biocompatible nanoparticles and biopolyelectrolytes.

  2. Nanoparticle Deposition onto Biofilms

    PubMed Central

    Miller, J.K.; Neubig, R.; Clemons, C.B.; Kreider, K.L.; Wilber, J.P.; Young, G.W.; Ditto, A.J.; Yun, Y.H.; Milsted, A.; Badawy, H.T.; Panzner, M.J.; Youngs, W.J.; Cannon, C.L.

    2012-01-01

    We develop a mathematical model of nanoparticles depositing onto and penetrating into a biofilm grown in a parallel-plate flow cell. We carry out deposition experiments in a flow cell to support the modeling. The modeling and the experiments are motivated by the potential use of polymer nanoparticles as part of a treatment strategy for killing biofilms infecting the deep passages in the lungs. In the experiments and model, a fluid carrying polymer nanoparticles is injected into a parallel-plate flow cell in which a biofilm has grown over the bottom plate. The model consists of a system of transport equations describing the deposition and diffusion of nanoparticles. Standard asymptotic techniques that exploit the aspect ratio of the flow cell are applied to reduce the model to two coupled partial differential equations. We perform numerical simulations using the reduced model. We compare the experimental observations with the simulation results to estimate the nanoparticle sticking coefficient and the diffusion coefficient of the nanoparticles in the biofilm. The distributions of nanoparticles through the thickness of the biofilm are consistent with diffusive transport, and uniform distributions through the thickness are achieved in about four hours. Nanoparticle deposition does not appear to be strongly influenced by the flow rate in the cell for the low flow rates considered. PMID:22878680

  3. Preparation and characterizations of silver incorporated polyurethane composite nanofibers via electrospinning for biomedical applications.

    PubMed

    Nirmala, R; Kalpana, Duraisamy; Navamathavan, R; Lee, Yang Soo; Kim, Hak Yong

    2013-07-01

    We report on the preparation and characterization of polyurethane (PU) nanofibers containing silver (Ag) nanoparticles were synthesized by using electrospinning. Two different approaches were adopted to incorporate the Ag nanoparticles in to PU nanofibers. In the first approach, a homogeneous solution of 10 wt% PU containing silver nitrate was electrospun to obtain PU-Ag composite nanofibers. And in the second approach, the pristine PU nanofibers were initially electrospun and then Ag nanoparticles were coated via wet casting method. The surface morphology, structure, bonding configuration, optical and thermal properties of the resultant products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, UV-vis spectroscopy and thermogravimetric analysis. The antibacterial activity was tested against four common food borne pathogenic bacteria, namely, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Klebsiella pneumoniae by minimum inhibitory concentration (MIC) method. Our results demonstrated that no bactericidal activity was detected for the pristine PU nanofibers. Further on, antibacterial activity was observed to be more pronounced for the composite nanofibers which were attributed to the presence of Ag nanoparticles in the composite nanofibers. Overall, this study demonstrates the fabrication of cheap, stable and effective nanofiber mats with excellent antimicrobial activity that can be utilized to inhibit the microbial growth associated with food stuff. PMID:23901491

  4. Magnetic Nanoparticle Degradation in vivo Studied by Mssbauer Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nikitin, Maxim; Gabbasov, Raul; Cherepanov, Valery; Chuev, Mikhail; Polikarpov, Mikhail; Panchenko, Vladislav; Deyev, Sergey

    2010-12-01

    Magnetic nanoparticles belong to the most promising nanosized objects for biomedical applications. However, little is known about clearance of magnetic nanoparticles from the organism. In this work superparamagnetic iron oxide particles fluidMAG-ARA were injected into tail vein of mice at a dose of 17 mg per 20 g body weight. At various time intervals after the injection the mice were sacrificed and their organs collected. A Mssbauer study allowed to detect magnetic particles in the liver and spleen and showed the degradation of the particles with incorporation of exogenous iron into paramagnetic ferritin-like iron species.

  5. Size Dependent Phase Diagrams of Nickel-Carbon Nanoparticles

    NASA Astrophysics Data System (ADS)

    Magnin, Y.; Zappelli, A.; Amara, H.; Ducastelle, F.; Bichara, C.

    2015-11-01

    The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nm (807 Ni atoms). A tight binding model for interatomic interactions drives the grand canonical Monte Carlo simulations used to locate solid, core shell and liquid stability domains, as a function of size, temperature, and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should lead to a better understanding of the nanotube growth mechanisms.

  6. Covalently functionalized gold nanoparticles: Synthesis, characterization, and integration into capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Ivanov, Michael Robert

    Nanomaterials are widely used as pseudostationary and stationary phases in electrically driven separations. The advantages of using nanomaterials are numerous including tunable sizes, multiple core compositions, flexible injection schemes, and diverse surface chemistries. Nanomaterials, however, exhibit large surface energies which induce aggregation and may yield unpredictable function in separations. Because nanomaterials can modify buffer conductivity, viscosity, and pH; successful and systematic incorporation of nanomaterials into separations requires rigorous synthetic control and characterization of both the nanoparticle core and surface chemistry. This dissertation investigates the impact of gold nanoparticle surface chemistry and morphology to capillary electrophoresis separations. Gold nanoparticle core composition, shape, size, self assembled monolayer (SAM) formation, and SAM packing density are quantified for gold nanoparticles functionalized with thioctic acid, 6-mercaptohexanoic acid, or 11-mercaptoundecanoic acid SAMs. TEM, 1H NMR, extinction spectroscopy, zeta potential, X-ray photoelectron spectroscopy, and flocculation assess the morphology, surface chemistry, optical properties, surface charge, SAM packing density, and stability of the nanoparticles, respectively. Using well-characterized nanostructures, pseudostationary phases of gold nanoparticles in capillary electrophoresis are studied. Gold nanoparticles functionalized with thioctic acid and either 6-mercaptohexanoic acid or 6-aminohexanethiol impact the mobility of analytes in a concentration and surface chemistry-dependent manner. From these data, a novel parameter termed the critical nanoparticle concentration is developed and is used to estimate nanoparticle stability during capillary electrophoresis separations. To understand the function of carboxylated gold nanoparticles in capillary electrophoresis, extended DLVO theory is used to model interparticle interactions. Nanoparticle aggregation leads to electron tunneling between nanoparticles thereby taking on bulk electrical properties which cause measured currents to increase for nanoparticles functionalized with poorly ordered SAMs. Nanoparticles functionalized with well-ordered SAMs main their nanoscale properties and reduce measured currents during electrically driven flow. Finally, carboxylic acid functionalized gold nanoparticles effect the separation of target biomarkers in both a SAM composition and surface coverage dependent manner. These effects are most systematic with well ordered SAMs. To understand the separation mechanism functionalized gold nanoparticles exhibit, their ? potential with and without dopamine are evaluated. Large dopamine concentrations neutralize the three functionalized gold nanoparticles according to a dose response curve. The positively charged dopamine molecules saturate the negatively charged nanoparticle surfaces thereby providing a plausible explanation to the observed biomarker concentration trends. These data and future work provide a rigorous experimental and theoretical evaluation of nanoparticle structure impacts their function as pseudostationary phases in separations and other applications.

  7. Industrial applications of nanoparticles.

    PubMed

    Stark, W J; Stoessel, P R; Wohlleben, W; Hafner, A

    2015-08-21

    Research efforts in the past two decades have resulted in thousands of potential application areas for nanoparticles - which materials have become industrially relevant? Where are sustainable applications of nanoparticles replacing traditional processing and materials? This tutorial review starts with a brief analysis on what makes nanoparticles attractive to chemical product design. The article highlights established industrial applications of nanoparticles and then moves to rapidly emerging applications in the chemical industry and discusses future research directions. Contributions from large companies, academia and high-tech start-ups are used to elucidate where academic nanoparticle research has revolutionized industry practice. A nanomaterial-focused analysis discusses new trends, such as particles with an identity, and the influence of modern instrument advances in the development of novel industrial products. PMID:25669838

  8. Single Nanoparticle Plasmonic Sensors

    PubMed Central

    Sriram, Manish; Zong, Kelly; Vivekchand, S. R. C.; Gooding, J. Justin

    2015-01-01

    The adoption of plasmonic nanomaterials in optical sensors, coupled with the advances in detection techniques, has opened the way for biosensing with single plasmonic particles. Single nanoparticle sensors offer the potential to analyse biochemical interactions at a single-molecule level, thereby allowing us to capture even more information than ensemble measurements. We introduce the concepts behind single nanoparticle sensing and how the localised surface plasmon resonances of these nanoparticles are dependent upon their materials, shape and size. Then we outline the different synthetic approaches, like citrate reduction, seed-mediated and seedless growth, that enable the synthesis of gold and silver nanospheres, nanorods, nanostars, nanoprisms and other nanostructures with tunable sizes. Further, we go into the aspects related to purification and functionalisation of nanoparticles, prior to the fabrication of sensing surfaces. Finally, the recent developments in single nanoparticle detection, spectroscopy and sensing applications are discussed. PMID:26473866

  9. Single Nanoparticle Plasmonic Sensors.

    PubMed

    Sriram, Manish; Zong, Kelly; Vivekchand, S R C; Gooding, J Justin

    2015-01-01

    The adoption of plasmonic nanomaterials in optical sensors, coupled with the advances in detection techniques, has opened the way for biosensing with single plasmonic particles. Single nanoparticle sensors offer the potential to analyse biochemical interactions at a single-molecule level, thereby allowing us to capture even more information than ensemble measurements. We introduce the concepts behind single nanoparticle sensing and how the localised surface plasmon resonances of these nanoparticles are dependent upon their materials, shape and size. Then we outline the different synthetic approaches, like citrate reduction, seed-mediated and seedless growth, that enable the synthesis of gold and silver nanospheres, nanorods, nanostars, nanoprisms and other nanostructures with tunable sizes. Further, we go into the aspects related to purification and functionalisation of nanoparticles, prior to the fabrication of sensing surfaces. Finally, the recent developments in single nanoparticle detection, spectroscopy and sensing applications are discussed. PMID:26473866

  10. Nanoparticles in Process Plasmas: Growth, Diagnostics, Applications

    NASA Astrophysics Data System (ADS)

    Winter, Jrg

    2004-09-01

    Process plasmas for thin film deposition and for etching often tend to form nanoparticles. In semiconductor processing particle formation has to be avoided because particle incorporation may lead to a lethal defect of the device. The ever decreasing feature size sets a size limit for such 'killer particles' to a few nanometres for the next generation of devices. In other applications, however, plasma grown nanoparticles are used to advantage. Examples are innovative dispersion materials, chemical catalysis, pharmacology, etc.. Understanding the growth mechanisms and the complex plasma-particle interactions are challenging questions. In situ particle diagnostics are instrumental for tackling these problems. In this contribution, the growth of carbonaceous nanoparticles from Ar- CH4 and from Ar- C_2H2 plasmas and the mutual interaction of particles and plasma will be discussed. The growth occurs via homogeneous nucleation involving negative ion- molecule-reactions, followed by rapid nucleation of protoparticles and further growth by accretion. It will be shown, that also in the case of Ar- CH4 the existence of C_2Hx precursors triggers the particle growth. When the particles are larger than a few nm, they are charged negatively on average and confined in the plasma. Small particles occupy essentially the whole plasma volume, heavy particles are suspended against gravity at the sheath edge with its high electric field. The in-situ diagnostics of nanoparticles is an important issue. Some examples will be presented using multipass FTIR absorption spectroscopy, Rayleigh-Mie Ellipsometry, laser light scattering, and the analysis of the complex impedance of the discharge. The latter method, though yielding a global information of the discharge, appears to be suited for industrial use. A big challenge is the detection of particles with diameters of a few nanometres light scattering gets increasingly difficult because of the r-6 dependence of the scattering cross section. Finally, examples for the use of nanoparticles in thin film deposition will be discussed.

  11. Functional Magnetic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Gass, James

    Nanoparticle system research and characterization is the focal point of this research and dissertation. In the research presented here, magnetite, cobalt, and ferrite nanoparticle systems have been explored in regard to their magnetocaloric effect (MCE) properties, as well as for use in polymer composites. Both areas of study have potential applications across a wide variety of interdisciplinary fields. Magnetite nanoparticles have been successfully dispersed in a polymer. The surface chemistry of the magnetic nanoparticle proves critical to obtaining a homogenous and well separated high density dispersion in PMMA. Theoretical studies found in the literature have indicated that surface interface energy is a critical component in dispersion. Oleic acid is used to alter the surface of magnetite nanoparticles and successfully achieve good dispersion in a PMMA thin film. Polypyrrole is then coated onto the PMMA composite layer. The bilayer is characterized using cross-sectional TEM, cross-sectional SEM, magnetic characterization, and low frequency conductivity. The results show that the superparmagnetic properties of the as synthesized particles are maintained in the composite. With further study of the properties of these nanoparticles for real and functional uses, MCE is studied on a variety of magnetic nanoparticle systems. Magnetite, manganese zinc ferrite, and cobalt ferrite systems show significant broadening of the MCE and the ability to tune the peak temperature of MCE by varying the size of the nanoparticles. Four distinct systems are studied including cobalt, cobalt core silver shell nanoparticles, nickel ferrite, and ball milled zinc ferrite. The results demonstrate the importance of surface characteristics on MCE. Surface spin disorder appears to have a large influence on the low temperature magnetic and magnetocalorie characteristics of these nanoparticle systems.

  12. Nanoparticle Approaches against Bacterial Infections

    PubMed Central

    Gao, Weiwei; Thamphiwatana, Soracha; Angsantikul, Pavimol; Zhang, Liangfang

    2014-01-01

    Despite the wide success of antibiotics, the treatment of bacterial infection still faces significant challenges, particularly the emergence of antibiotic resistance. As a result, nanoparticle drug delivery platforms including liposomes, polymeric nanoparticles, dendrimers, and various inorganic nanoparticles have been increasingly exploited to enhance the therapeutic effectiveness of existing antibiotics. This review focuses on areas where nanoparticle approaches hold significant potential to advance the treatment of bacterial infection. These areas include targeted antibiotic delivery, environmentally responsive antibiotic delivery, combinatorial antibiotic delivery, nanoparticle-enabled antibacterial vaccination, and nanoparticle-based bacterial detection. In each area we highlight the innovative antimicrobial nanoparticle platforms and review their progress made against bacterial infections. PMID:25044325

  13. Understanding the physics of magnetic nanoparticles and their applications in the biomedical field

    NASA Astrophysics Data System (ADS)

    Laha, Suvra Santa

    The study of magnetic nanoparticles is of great interest because of their potential uses in magnetic-recording, medical diagnostic and therapeutic applications. Additionally, they also offer an opportunity to understand the physics underlying the complex behavior exhibited by these materials. Two of the most important relaxation phenomena occurring in magnetic nanoparticles are superparamagnetic blocking and spin-glass-like freezing. In addition to features attributed to superparamagnetism, these nanoparticles can also exhibit magnetic relaxation effects at very low temperatures (≤ 50 K). Our studies suggest that all structural defects, and not just surface spins, are responsible for the low-temperature glass-like relaxation observed in many magnetic nanoparticles. The characteristic dipolar interaction energy existing in an ensemble of magnetic nanoparticles does not apparently depend on the average spacing between the nanoparticles but is likely to be strongly influenced by the fluctuations in the nanoparticle distribution. Our findings revealed that incorporating a small percentage of boron can stabilize the spinel structure in Mn 3O4 nanoparticles. We have also demonstrated that the dipolar interactions between the magnetic cores can be tuned by introducing non-magnetic nanoparticles. In particular, we studied the magnetic properties of Gd-doped Fe3O4 nanoparticles, a potential applicant for T1--T2 dual-modal MRI contrast agent. We have explored the interactions of BiFeO3 nanoparticles on live cells and the binding of FITC-conjugated Fe3O 4 nanoparticles with artificial lipid membranes to investigate these materials as candidates in medical imaging. Taken together, these studies have advanced our understanding of the fundamental physical principles that governs magnetism in magnetic materials with a focus on developing these nanoparticles for advanced biomedical applications. The materials developed and studied expand the repertoire of tools available for multimodal imaging, using both x-ray and magnetic resonance.

  14. A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells.

    PubMed

    Freitas, Jilian N; Gonalves, Agnaldo S; Nogueira, Ana F

    2014-06-21

    In this review the use of solution-processed chalcogenide quantum dots (CdS, CdSe, PbS, etc.) in hybrid organic-inorganic solar cells is explored. Such devices are known as potential candidates for low-cost and efficient solar energy conversion, and compose the so-called third generation solar cells. The incorporation of oxides and metal nanoparticles has also been successfully achieved in this new class of photovoltaic devices; however, we choose to explore here chalcogenide quantum dots in light of their particularly attractive optical and electronic properties. We address herein a comprehensive review of the historical background and state-of-the-art comprising the incorporation of such nanoparticles in polymer matrices. Later strategies for surface chemistry manipulation, in situ synthesis of nanoparticles, use of continuous 3D nanoparticles network (aerogels) and ternary systems are also reviewed. PMID:24839190

  15. A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells

    NASA Astrophysics Data System (ADS)

    Freitas, Jilian N.; Gonalves, Agnaldo S.; Nogueira, Ana F.

    2014-05-01

    In this review the use of solution-processed chalcogenide quantum dots (CdS, CdSe, PbS, etc.) in hybrid organic-inorganic solar cells is explored. Such devices are known as potential candidates for low-cost and efficient solar energy conversion, and compose the so-called third generation solar cells. The incorporation of oxides and metal nanoparticles has also been successfully achieved in this new class of photovoltaic devices; however, we choose to explore here chalcogenide quantum dots in light of their particularly attractive optical and electronic properties. We address herein a comprehensive review of the historical background and state-of-the-art comprising the incorporation of such nanoparticles in polymer matrices. Later strategies for surface chemistry manipulation, in situ synthesis of nanoparticles, use of continuous 3D nanoparticles network (aerogels) and ternary systems are also reviewed.

  16. Characterisation of copper oxide nanoparticles for antimicrobial applications.

    PubMed

    Ren, Guogang; Hu, Dawei; Cheng, Eileen W C; Vargas-Reus, Miguel A; Reip, Paul; Allaker, Robert P

    2009-06-01

    Copper oxide (CuO) nanoparticles were characterised and investigated with respect to potential antimicrobial applications. It was found that nanoscaled CuO, generated by thermal plasma technology, contains traces of pure Cu and Cu2O nanoparticles. Transmission electron microscopy (TEM) demonstrated particle sizes in the range 20-95 nm. TEM energy dispersive spectroscopy gave the ratio of copper to oxygen elements as 54.18% to 45.26%. The mean surface area was determined as 15.69 m(2)/g by Brunau-Emmet-Teller (BET) analysis. CuO nanoparticles in suspension showed activity against a range of bacterial pathogens, including meticillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli, with minimum bactericidal concentrations (MBCs) ranging from 100 microg/mL to 5000 microg/mL. The ability of CuO nanoparticles to reduce bacterial populations to zero was enhanced in the presence of sub-MBC concentrations of silver nanoparticles. Studies of CuO nanoparticles incorporated into polymers suggest release of ions may be required for optimum killing. PMID:19195845

  17. Applications and toxicity of silver nanoparticles: a recent review.

    PubMed

    Marin, Stefania; Vlasceanu, George Mihail; Tiplea, Roxana Elena; Bucur, Ioana Raluca; Lemnaru, Madalina; Marin, Maria Minodora; Grumezescu, Alexandru Mihai

    2015-01-01

    Silver nanoparticles (AgNPs) exhibit a consistent amount of flexible properties which endorse them for a larger spectrum of applications in biomedicine and related fields. Over the years, silver nanoparticles have been subjected to numerous in vitro and in vivo tests to provide information about their toxic behavior towards living tissues and organisms. Researchers showed that AgNPs have high antimicrobial efficacy against many bacteria species including Escherichia coli, Neisseria gonorrhea, Chlamydia trachomatis and also viruses. Due to their novel properties, the incorporation of silver nanoparticles into different materials like textile fibers and wound dressings can extend their utility on the biomedical field while inhibiting infections and biofilm development. Among the noble metal nanoparticles, AgNPs present a series of features like simple synthesis routes, adequate and tunable morphology, and high surface to volume ratio, intracellular delivery system, a large plasmon field area recommending them as ideal biosensors, catalysts or photo-controlled delivery systems. In bioengineering, silver nanoparticles are considered potentially ideal gene delivery systems for tissue regeneration. The remote triggered detection and release of bioactive compounds of silver nanoparticles has proved their relevance also in forensic sciences. The authors report an up to date review related to the toxicity of AgNPs and their applications in antimicrobial activity and biosensors for gene therapy. PMID:25877089

  18. Oscillatory characteristics of metallic nanoparticles inside lipid nanotubes

    NASA Astrophysics Data System (ADS)

    Sadeghi, Fatemeh; Ansari, Reza; Darvizeh, Mansour

    2015-12-01

    This study is concerned with the oscillatory behavior of metallic nanoparticles, and in particular silver and gold nanoparticles, inside lipid nanotubes (LNTs) using the continuum approximation along with the 6-12 Lennard-Jones (LJ) potential function. The nanoparticle is modeled as a dense sphere and the LNT is assumed to be comprised of six layers including two head groups, two intermediate layers and two tail groups. To evaluate van der Waals (vdW) interactions, analytical expressions are first derived through undertaking surface and volume integrals which are then validated by a fully numerical scheme based on the differential quadrature (DQ) technique. Using the actual force distribution between the two interacting molecules, the equation of motion is directly solved utilizing the Runge-Kutta numerical integration scheme to arrive at the time history of displacement and velocity of the inner core. Also, a semi-analytical expression incorporating both geometrical parameters and initial conditions is introduced for the precise evaluation of oscillation frequency. A comprehensive study is conducted to gain an insight into the influences of nanoparticle radius, LNT length, head and tail group thicknesses and initial conditions on the oscillatory behavior of the metallic nanoparticles inside LNTs. It is found that the escape velocity and oscillation frequency of silver nanoparticles are higher than those of gold ones. It is further shown that the oscillation frequency is less affected by the tail group thickness when compared to the head group thickness.

  19. No evidence for cerium dioxide nanoparticle translocation in maize plants.

    PubMed

    Birbaum, Karin; Brogioli, Robert; Schellenberg, Maya; Martinoia, Enrico; Stark, Wendelin J; Gnther, Detlef; Limbach, Ludwig K

    2010-11-15

    The rapidly increasing production of engineered nanoparticles has raised questions regarding their environmental impact and their mobility to overcome biological important barriers. Nanoparticles were found to cross different mammalian barriers, which is summarized under the term translocation. The present work investigates the uptake and translocation of cerium dioxide nanoparticles into maize plants as one of the major agricultural crops. Nanoparticles were exposed either as aerosol or as suspension. Our study demonstrates that 50 ?g of cerium/g of leaves was either adsorbed or incorporated into maize leaves. This amount could not be removed by a washing step and did not depend on closed or open stomata investigated under dark and light exposure conditions. However, no translocation into newly grown leaves was found when cultivating the maize plants after airborne particle exposure. The use of inductively coupled mass spectrometer allowed detection limits of less than 1 ng of cerium/g of leaf. Exposure of plants to well-characterized nanoparticle suspensions in the irrigation water resulted also in no detectable translocation. These findings may indicate that the biological barriers of plants are more resistant against nanoparticle translocation than mammalian barriers. PMID:20964359

  20. Ultrasmall lanthanide-doped nanoparticles as multimodal platforms

    NASA Astrophysics Data System (ADS)

    Yust, Brian G.; Pedraza, Francisco J.; Sardar, Dhiraj K.

    2014-03-01

    Recently, there has been a great amount of interest in nanoparticles which are able to provide a platform with high contrast for multiple imaging modalities in order to advance the tools available to biomedical researchers and physicians. However, many nanoparticles do not have ideal properties to provide high contrast in different imaging modes. In order to address this, ultrasmall lanthanide doped oxide and fluoride nanoparticles with strong NIR to NIR upconversion fluorescence and a strong magnetic response for magnetic resonance imaging (MRI) have been developed. Specifically, these nanoparticles incorporate gadolinium, dysprosium, or a combination of both into the nano-crystalline host to achieve the magnetic properties. Thulium, erbium, and neodymium codopants provide the strong NIR absorption and emission lines that allow for deeper tissue imaging since near infrared light is not strongly absorbed or scattered by most tissues within this region. This also leads to better image quality and lower necessary excitation intensities. As a part of the one pot synthesis, these nanoparticles are coated with peg, pmao, or d-glucuronic acid to make them water soluble, biocompatible, and bioconjugable due to the available carboxyl or amine groups. Here, the synthesis, morphological characterization, magnetic response, NIR emission, and the quantum yield will be discussed. Cytotoxicity tested through cell viability at varying concentrations of nanoparticles in growth media will also be discussed.

  1. Preparations of bifunctional polymeric beads simultaneously incorporated with fluorescent quantum dots and magnetic nanocrystals

    NASA Astrophysics Data System (ADS)

    Tu, Chifeng; Yang, Yunhua; Gao, Mingyuan

    2008-03-01

    Bifunctional polystyrene beads simultaneously incorporated with fluorescent CdTe quantum dots (Q-dots) and superparamagnetic Fe3O4 nanocrystals were prepared by a modified mini-emulsion polymerization method, in which polymerizable surfactants were used as both phase transfer agent for aqueous colloidal nanoparticles and emulsifier. In addition, silica coating was also introduced to Fe3O4 nanocrystals for regulating the internal structure of the composite beads. Transmission electron microscopy, confocal fluorescence microscopy and conventional spectroscopy were used to characterize the composite beads, as well as the polymerizable surfactant-coated CdTe Q-dots and silica-coated Fe3O4 nanoparticles. Different mixing methods were also attempted in order to vary the size of the resultant bifunctional beads.

  2. Incorporating Reading Skills into Art Lessons.

    ERIC Educational Resources Information Center

    Peragallo, Anne M.

    1981-01-01

    Using a ceramics unit, the author illustrates ways of incorporating the following reading skills into an art lesson: following directions; pronunciation, spelling, and vocabulary development; interpreting illustrations; using reference books and materials; notetaking; and skimming. (SJL)

  3. 49 CFR 572.80 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the materials may be obtained from Rowley-Scher... 49 Transportation 7 2013-10-01 2013-10-01 false Incorporated materials. 572.80 Section 572.80... Incorporated materials. The drawings and specifications referred to in § 572.81(a) that are not set forth...

  4. 49 CFR 572.80 - Incorporated materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the materials may be obtained from Rowley-Scher... 49 Transportation 7 2010-10-01 2010-10-01 false Incorporated materials. 572.80 Section 572.80... Incorporated materials. The drawings and specifications referred to in § 572.81(a) that are not set forth...

  5. 49 CFR 572.80 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the materials may be obtained from Rowley-Scher... 49 Transportation 7 2011-10-01 2011-10-01 false Incorporated materials. 572.80 Section 572.80... Incorporated materials. The drawings and specifications referred to in § 572.81(a) that are not set forth...

  6. 49 CFR 572.80 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the materials may be obtained from Rowley-Scher... 49 Transportation 7 2012-10-01 2012-10-01 false Incorporated materials. 572.80 Section 572.80... Incorporated materials. The drawings and specifications referred to in § 572.81(a) that are not set forth...

  7. 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. PMID:26605438

  8. Prevention of coalescence during annealing of FePt nanoparticles assembled by convective coating.

    PubMed

    Hwang, Yeon; Park, Jong-Sung; Choi, Young Jin; Suh, Yong Jae; Lee, Hyo-Sook; Kang, Dae Sik; Lee, Jong Kook

    2010-05-01

    FePt nanoparticle suspension was synthesized by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine. The composition of the synthesized nanoparticles was Fe40Pt60. To prevent the coalescence during annealing of FePt nanoparticles we tried two steps of convective coating, where first coating was for silica particle assembly on a silicon substrate and second one was for FePt nanoparticles on the silica layers. It was observed by scanning electron microscopy that FePt nanoparticles were dispersed on the silica surface. After being annealed at 700 degrees C for 30 minutes under nitrogen atmosphere, the particle size of FePt nanoparticles increased slightly from 4 nm to 6 nm but dispersity of the nanoparticles was maintained. Magnetic hysteresis of Fe40Pt60 nanoparticles coating on silica layer after annealing showed typical characteristics of hard magnetic materials, and no incorporation of soft magnetic materials. It was suggested that convective self-assembly with the parallel use of pre-coating that offers solvent flux weakening capillary force between FePt nanoparticles was an effective method to prevent coalescence of nano-sized particles under high temperature annealing. PMID:20358990

  9. Novel ionically crosslinked casein nanoparticles for flutamide delivery: formulation, characterization, and in vivo pharmacokinetics

    PubMed Central

    Elzoghby, Ahmed O; Helmy, Maged W; Samy, Wael M; Elgindy, Nazik A

    2013-01-01

    A novel particulate delivery matrix based on ionically crosslinked casein (CAS) nanoparticles was developed for controlled release of the poorly soluble anticancer drug flutamide (FLT). Nanoparticles were fabricated via oil-in-water emulsification then stabilized by ionic crosslinking of the positively charged CAS molecules below their isoelectric point, with the polyanionic crosslinker sodium tripolyphosphate. With the optimal preparation conditions, the drug loading and incorporation efficiency achieved were 8.73% and 64.55%, respectively. The nanoparticles exhibited a spherical shape with a size below 100 nm and a positive zeta potential (+7.54 to +17.3 mV). FLT was molecularly dispersed inside the nanoparticle protein matrix, as revealed by thermal analysis. The biodegradability of CAS nanoparticles in trypsin solution could be easily modulated by varying the sodium tripolyphosphate crosslinking density. A sustained release of FLT from CAS nanoparticles for up to 4 days was observed, depending on the crosslinking density. After intravenous administration of FLT-CAS nanoparticles into rats, CAS nanoparticles exhibited a longer circulation time and a markedly delayed blood clearance of FLT, with the half-life of FLT extended from 0.88 hours to 14.64 hours, compared with drug cosolvent. The results offer a promising method for tailoring biodegradable, drug-loaded CAS nanoparticles as controlled, long-circulating drug delivery systems of hydrophobic anticancer drugs in aqueous vehicles. PMID:23658490

  10. Recent advances in lipid nanoparticle formulations with solid matrix for oral drug delivery.

    PubMed

    Das, Surajit; Chaudhury, Anumita

    2011-03-01

    Lipid nanoparticles based on solid matrix have emerged as potential drug carriers to improve gastrointestinal (GI) absorption and oral bioavailability of several drugs, especially lipophilic compounds. These formulations may also be used for sustained drug release. Solid lipid nanoparticle (SLN) and the newer generation lipid nanoparticle, nanostructured lipid carrier (NLC), have been studied for their capability as oral drug carriers. Biodegradable, biocompatible, and physiological lipids are generally used to prepare these nanoparticles. Hence, toxicity problems related with the polymeric nanoparticles can be minimized. Furthermore, stability of the formulations might increase than other liquid nano-carriers due to the solid matrix of these lipid nanoparticles. These nanoparticles can be produced by different formulation techniques. Scaling up of the production process from lab scale to industrial scale can be easily achieved. Reasonably high drug encapsulation efficiency of the nanoparticles was documented. Oral absorption and bioavailability of several drugs were improved after oral administration of the drug-loaded SLNs or NLCs. In this review, pros and cons, different formulation and characterization techniques, drug incorporation models, GI absorption and oral bioavailability enhancement mechanisms, stability and storage condition of the formulations, and recent advances in oral delivery of the lipid nanoparticles based on solid matrix will be discussed. PMID:21174180

  11. Nanoparticle flotation collectors II: the role of nanoparticle hydrophobicity.

    PubMed

    Yang, Songtao; Pelton, Robert

    2011-09-20

    The ability of polystyrene nanoparticles to facilitate the froth flotation of glass beads was correlated to the hydrophobicity of the nanoparticles. Contact angle measurements were used to probe the hydrophobicity of hydrophilic glass surfaces decorated with hydrophobic nanoparticles. Both sessile water drop advancing angles, θ(a), and attached air bubble receding angle measurements, θ(r), were performed. For glass surfaces saturated with adsorbed nanoparticles, flotation recovery, a measure of flotation efficiency, increased with increasing values of each type of contact angle. As expected, the advancing water contact angle on nanoparticle-decorated, dry glass surfaces increased with surface coverage, the area fraction of glass covered with nanoparticles. However, the nanoparticles were far more effective at raising the contact angle than the Cassie-Baxter prediction, suggesting that with higher nanoparticle coverages the water did not completely wet the glass surfaces between the nanoparticles. A series of polystyrene nanoparticles was prepared to cover a range of surface energies. Water contact angle measurements, θ(np), on smooth polymer films formed from organic solutions of dissolved nanoparticles were used to rank the nanoparticles in terms of hydrophobicity. Glass spheres were saturated with adsorbed nanoparticles and were isolated by flotation. The minimum nanoparticle water contact angle to give high flotation recovery was in the range of 51° < θ(np(min)) ≤ 85°. PMID:21830818

  12. NIR fluorescent silica nanoparticles as reporting labels in bioanalytical applications

    NASA Astrophysics Data System (ADS)

    Patonay, Gabor; Henary, Maged; Chapman, Gala; Emer, Kyle; Crow, Sydney

    2015-03-01

    The use of the NIR spectral region (650-900 nm) for bioanalytical and biomedical analyses is advantageous due to the inherently lower background interference in biological matrices and the high molar absorptivities of NIR chromophores. There are several different groups of NIR fluorescing dye are available for bioanalytical applications. One of these groups, NIR carbocyanines are increasingly used in analytical, bioanalytical and medical applications. These dyes can be used as reporter labels for sensitive bioanalytical use, such as immunochemistry. Due to the spectroscopic sensitivity of NIR carbocyanines for polarity changes in the microenvironment fluorescence quantum yield can vary significantly dependent on the microenvironment. NIR dyes can have relatively low fluorescent quantum yields as compared to visible fluorophores, especially in aqueous buffers but the lower quantum yield is compensated for by a much higher molar absorptivity. The fluorescence intensity of NIR reporting labels can significantly be increased by enclosing several dye molecules in silica nanoparticles. Incorporation of NIR dyes in silica nanoparticles creates a unique challenge as these dyes can be unstable under certain chemical conditions present during silica nanoparticles syntheses. In addition, self quenching may also become a problem for carbocyanines at higher a concentrations that typically found inside of NIR dye loaded silica nanoparticles. Dyes possessing high Stokes' shift can significantly reduce this problem. NIR carbocyanines are uniquely positioned for achieving this goal using a synthetic route that substitutes meso position halogens in NIR fluorescent carbocyanines with a linker containing amino moiety, which can also serve as a linker for covalently attaching the dye molecule to the nanoparticle backbone. The resulting silica nanoparticles can contain a large number of NIR dyes dependent on their size. For example some NIR fluorescent silica nanoparticle labels prepared that has an average radius around 15 nm, contains 16-20 covalently attached dye molecules inside of the nanoparticle. The primary applications of these particles are for bright fluorescent labels that can be used in applications such as immunochemistry, flow cytometry, and many other applications.

  13. Gas Phase Nanoparticle Synthesis

    NASA Astrophysics Data System (ADS)

    Granqvist, Claes; Kish, Laszlo; Marlow, William

    This book deals with gas-phase nanoparticle synthesis and is intended for researchers and research students in nanomaterials science and engineering, condensed matter physics and chemistry, and aerosol science. Gas-phase nanoparticle synthesis is instrumental to nanotechnology - a field in current focus that raises hopes for environmentally benign, resource-lean manufacturing. Nanoparticles can be produced by many physical, chemical, and even biological routes. Gas-phase synthesis is particularly interesting since one can achieve accurate manufacturing control and hence industrial viability.

  14. Improvement of thermal stability of polypropylene using DOPO-immobilized silica nanoparticles

    PubMed Central

    Dong, Quanxiao; Ding, Yanfen; Wen, Bin; Wang, Feng; Dong, Huicong; Zhang, Shimin

    2014-01-01

    After the surface silylation with 3-methacryloxypropyltrimethoxysilane, silica nanoparticles were further modified by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The immobilization of DOPO on silica nanoparticles was confirmed by Fourier transform infrared spectroscopy, UVvisible spectroscopy, magic angle spinning nuclear magnetic resonance, and thermogravimetric analysis. By incorporating the DOPO-immobilized silica nanoparticles (5 wt%) into polypropylene matrix, the thermal oxidative stability exhibited an improvement of 62 C for the half weight loss temperature, while that was only 26 C increment with incorporation of virgin silica nanoparticles (5 wt%). Apparent activation energies of the polymer nanocomposites were estimated via FlynnWallOzawa method. It was found that the incorporation of DOPO-immobilized silica nanoparticles improved activation energies of the degradation reaction. Based on the results, it was speculated that DOPO-immobilized silica nanoparticles could inhibit the degradation of polypropylene and catalyze the formation of carbonaceous char on the surface. Thus, thermal stability was significantly improved. PMID:24729654

  15. Radiolabelled nanoparticles: novel classification of radiopharmaceuticals for molecular imaging of cancer.

    PubMed

    Mirshojaei, Seyedeh Fatemeh; Ahmadi, Amirhossein; Morales-Avila, Enrique; Ortiz-Reynoso, Mariana; Reyes-Perez, Horacio

    2016-02-01

    Nanotechnology has been used for every single modality in the molecular imaging arena for imaging purposes. Synergic advantages can be explored when multiple molecular imaging modalities are combined with respect to single imaging modalities. Multifunctional nanoparticles have large surface areas, where multiple functional moieties can be incorporated, including ligands for site-specific targeting and radionuclides, which can be detected to create 3D images. Recently, radiolabeled nanoparticles with individual properties have attracted great interest regarding their use in multimodality tumor imaging. Multifunctional nanoparticles can combine diagnostic and therapeutic capabilities for both target-specific diagnosis and the treatment of a given disease. The future of nanomedicine lies in multifunctional nanoplatforms that combine the diagnostic ability and therapeutic effects using appropriate ligands, drugs, responses and technological devices, which together are collectively called theranostic drugs. Co-delivery of radiolabeled nanoparticles is useful in multifunctional molecular imaging areas because it comprises several advantages based on nanoparticles architecture, pharmacokinetics and pharmacodynamic properties. PMID:26061297

  16. Effect of Gold Nanoparticle on Structure and Fluidity of Lipid Membrane

    PubMed Central

    Mhashal, Anil R.; Roy, Sudip

    2014-01-01

    This paper deals with the effect of different size gold nanoparticles on the fluidity of lipid membrane at different regions of the bilayer. To investigate this, we have considered significantly large bilayer leaflets and incorporated only one nanoparticle each time, which was subjected to all atomistic molecular dynamics simulations. We have observed that, lipid molecules located near to the gold nanoparticle interact directly with it, which results in deformation of lipid structure and slower dynamics of lipid molecules. However, lipid molecules far away from the interaction site of the nanoparticle get perturbed, which gives rise to increase in local ordering of the lipid domains and decrease in fluidity. The bilayer thickness and area per head group in this region also get altered. Similar trend, but with different magnitude is also observed when different size nanoparticle interact with the bilayer. PMID:25469786

  17. Spray-coated nanoscale conductive patterns based on in situ sintered silver nanoparticle inks

    PubMed Central

    2014-01-01

    Nanoscale patterns with high conductivity based on silver nanoparticle inks were fabricated using spray coating method. Through optimizing the solution content and spray operation, accurate nanoscale patterns consisting of silver nanoparticles with a square resistance lower than 1 Ω /cm2 were obtained. By incorporating in situ sintering to substitute the general post sintering process, the time consumption could be significantly reduced to one sixth, qualifying it for large-scale and cost-effective fabrication of printed electronics. To testify the application of spray-coated silver nanoparticle inks, an inverted polymer solar cell was also fabricated, which exhibited a power conversion efficiency of 2.76%. PMID:24666992

  18. Spray-coated nanoscale conductive patterns based on in situ sintered silver nanoparticle inks.

    PubMed

    Zheng, Yifan; Li, Shuguang; Shi, Wei; Yu, Junsheng

    2014-01-01

    Nanoscale patterns with high conductivity based on silver nanoparticle inks were fabricated using spray coating method. Through optimizing the solution content and spray operation, accurate nanoscale patterns consisting of silver nanoparticles with a square resistance lower than 1 ? /cm2 were obtained. By incorporating in situ sintering to substitute the general post sintering process, the time consumption could be significantly reduced to one sixth, qualifying it for large-scale and cost-effective fabrication of printed electronics. To testify the application of spray-coated silver nanoparticle inks, an inverted polymer solar cell was also fabricated, which exhibited a power conversion efficiency of 2.76%. PMID:24666992

  19. Spray-coated nanoscale conductive patterns based on in situ sintered silver nanoparticle inks

    NASA Astrophysics Data System (ADS)

    Zheng, Yifan; Li, Shuguang; Shi, Wei; Yu, Junsheng

    2014-03-01

    Nanoscale patterns with high conductivity based on silver nanoparticle inks were fabricated using spray coating method. Through optimizing the solution content and spray operation, accurate nanoscale patterns consisting of silver nanoparticles with a square resistance lower than 1 ? /cm2 were obtained. By incorporating in situ sintering to substitute the general post sintering process, the time consumption could be significantly reduced to one sixth, qualifying it for large-scale and cost-effective fabrication of printed electronics. To testify the application of spray-coated silver nanoparticle inks, an inverted polymer solar cell was also fabricated, which exhibited a power conversion efficiency of 2.76%.

  20. Surface modification strategies on mesoporous silica nanoparticles for anti-biofouling zwitterionic film grafting.

    PubMed

    Khung, Yit Lung; Narducci, Dario

    2015-12-01

    In the past decade, zwitterionic-based anti-biofouling layers had gained much focus as a serious alternative to traditional polyhydrophilic films such as PEG. In the area of assembling silica nanoparticles with stealth properties, the incorporation of zwitterionic surface film remains fairly new but considering that silica nanoparticles had been widely demonstrated as useful biointerfacing nanodevice, zwitterionic film grafting on silica nanoparticle holds much potential in the future. This review will discuss on the conceivable functional chemistry approaches, some of which are potentially suitable for the assembly of such stealth systems. PMID:26589704

  1. Preparation and luminescent properties of GdOF:Ce, Tb nanoparticles and their transparent PMMA nanocomposites

    NASA Astrophysics Data System (ADS)

    Cai, Wen; Wang, Aiwu; Fu, Li; Hu, Jie; Rao, Tingke; Wang, Junqing; Zhong, Jiasong; Xiang, Weidong

    2015-05-01

    GdOF:Ce, Tb nanoparticles and their poly (methyl methacrylate) (PMMA) nanocomposites have been successfully prepared by a thermolysis route and thermal polymerization of methyl methacrylate (MMA) monomer, respectively. The obtained nanoparticles and nanocomposites are characterized by XRD, EDS, TEM, FTIR, TGA, UV-Vis and PL spectrum. The as-synthesized transparent GdOF:Ce, Tb/PMMA nanocomposites exhibit green photoluminescence under the irradiation of 254 nm UV lamp due to the incorporation of luminescent GdOF:Ce, Tb nanoparticles into the PMMA matrix. The present route would provide a general strategy to prepare other functional nanocomposites.

  2. Electrosprayed nanoparticles for drug delivery and pharmaceutical applications

    PubMed Central

    Sridhar, Radhakrishnan; Ramakrishna, Seeram

    2013-01-01

    Nanotechnology based Pharma has emerged significantly and has influenced the Pharma industry up to a considerable extent. Nanoparticles technology holds a good share of the nanotech Pharma and is significant in comparison with the other domains. Electrospraying technology answers the potential needs of nanoparticle production such as scalability, reproducibility, effective encapsulation etc. Many drugs have been electrosprayed with and without polymer carriers. Drug release characteristics are improved with the incorporation of biodegradable polymer carriers which sustain the release of encapsulated drug. Electrospraying is acknowledged as an important technique for the preparation of nanoparticles with respect to pharmaceutical applications. Herein we attempted to consolidate the reports pertaining to electrospraying and their corresponding therapeutic application area. PMID:23512013

  3. Effects of Gold Nanoparticles on the Response of Phenol Biosensor Containing Photocurable Membrane with Tyrosinase

    PubMed Central

    Hanifah, Sharina Abu; Heng, Lee Yook; Ahmad, Musa

    2008-01-01

    The role of incorporation of gold nanoparticles (50-130 nm in diameter) into a series of photocurable methacrylic-acrylic based biosensor membranes containing tyrosinase on the response for phenol detection was investigated. Membranes with different hydrophilicities were prepared from 2-hydroxyethyl methacrylate and n-butyl acrylate via direct photocuring. A range of gold nanoparticles concentrations from 0.01 to 0.5 % (w/w) was incorporated into these membranes during the photocuring process. The addition of gold nanoparticles to the biosensor membrane led to improvement in the response time by a reduction of approximately 5 folds to give response times of 5-10 s. The linear response range of the phenol biosensor was also extended from 24 to 90 ?M of phenol. The hydrophilicities of the membrane matrices demonstrated strong influence on the biosensor response and appeared to control the effect of the gold nanoparticles. For less hydrophilic methacrylic-acrylic membranes, the addition of gold nanoparticles led to a poorer sensitivity and detection limit of the biosensor towards phenol. Therefore, for the application of gold nanoparticles in the enhancement of a phenol biosensor response, the nanoparticles should be immobilized in a hydrophilic matrix rather than a hydrophobic material.

  4. Fabrication, Modeling and Characterization of Multi-Crosslinked Methacrylate Copolymeric Nanoparticles for Oral Drug Delivery

    PubMed Central

    Ngwuluka, Ndidi C.; Pillay, Viness; Choonara, Yahya E.; Modi, Girish; Naidoo, Dinesh; du Toit, Lisa C.; Kumar, Pradeep; Ndesendo, Valence M.K.; Khan, Riaz A.

    2011-01-01

    Nanotechnology remains the field to explore in the quest to enhance therapeutic efficacies of existing drugs. Fabrication of a methacrylate copolymer-lipid nanoparticulate (MCN) system was explored in this study for oral drug delivery of levodopa. The nanoparticles were fabricated employing multicrosslinking technology and characterized for particle size, zeta potential, morphology, structural modification, drug entrapment efficiency and in vitro drug release. Chemometric Computational (CC) modeling was conducted to deduce the mechanism of nanoparticle synthesis as well as to corroborate the experimental findings. The CC modeling deduced that the nanoparticles synthesis may have followed the mixed triangular formations or the mixed patterns. They were found to be hollow nanocapsules with a size ranging from 152 nm (methacrylate copolymer) to 321 nm (methacrylate copolymer blend) and a zeta potential range of 15.843.3 mV. The nanoparticles were directly compressible and it was found that the desired rate of drug release could be achieved by formulating the nanoparticles as a nanosuspension, and then directly compressing them into tablet matrices or incorporating the nanoparticles directly into polymer tablet matrices. However, sustained release of MCNs was achieved only when it was incorporated into a polymer matrix. The experimental results were well corroborated by the CC modeling. The developed technology may be potentially useful for the fabrication of multi-crosslinked polymer blend nanoparticles for oral drug delivery. PMID:22016653

  5. Highly quasi-monodisperse ag nanoparticles on titania nanotubes by impregnative aqueous ion exchange.

    PubMed

    Toledo-Antonio, J A; Cortes-Jcome, M A; Angeles-Chavez, C; Lpez-Salinas, E; Quintana, P

    2009-09-01

    Silver nanoparticles were homogenously dispersed on titania nanotubes (NT), which were prepared by alkali hydrothermal methodology and dried at 373 K. Ag(+) incorporation was done by impregnative ion exchange of aqueous silver nitrate onto NT. First, Ag(+) ions incorporate into the layers of nanotube walls, and then, upon heat treatment under N(2) at 573 and 673 K, they migrate and change into Ag(2)O and Ag(0) nanoparticles, respectively. In both cases, Ag nanoparticles are highly dispersed, decorating the nanotubes in a polka-dot pattern. The Ag particle size distribution is very narrow, being ca. 4 +/- 2 nm without any observable agglomeration. The reduction of Ag(2)O into Ag(0) octahedral nanoparticles occurs spontaneously and topotactically when annealing, without the aid of any reducing agent. The population of Ag(0) nanoparticles can be controlled by adjusting the annealing temperature. An electron charge transfer from NT support to Ag(0) nanoparticles, because of a strong interaction, is responsible for considerable visible light absorption in Ag(0) nanoparticles supported on NT. PMID:19485374

  6. Physiologically Based Pharmacokinetic Modeling of Fluorescently Labeled Block Copolymer Nanoparticles for Controlled Drug Delivery in Leukemia Therapy

    PubMed Central

    Gilkey, MJ; Krishnan, V; Scheetz, L; Jia, X; Rajasekaran, AK; Dhurjati, PS

    2015-01-01

    A physiologically based pharmacokinetic (PBPK) model was developed that describes the concentration and biodistribution of fluorescently labeled nanoparticles in mice used for the controlled delivery of dexamethasone in acute lymphoblastic leukemia (ALL) therapy. The simulated data showed initial spikes in nanoparticle concentration in the liver, spleen, and kidneys, whereas concentration in plasma decreased rapidly. These simulation results were consistent with previously published in vivo data. At shorter time scales, the simulated data predicted decrease of nanoparticles from plasma with concomitant increase in the liver, spleen, and kidneys before decaying at longer timepoints. Interestingly, the simulated data predicted an unaccounted accumulation of about 50% of the injected dose of nanoparticles. Incorporation of an additional compartment into the model justified the presence of unaccounted nanoparticles in this compartment. Our results suggest that the proposed PBPK model can be an excellent tool for prediction of optimal dose of nanoparticle-encapsulated drugs for cancer treatment. PMID:26225236

  7. Drug Delivery Nanoparticles in Skin Cancers

    PubMed Central

    Dianzani, Chiara; Zara, Gian Paolo; Maina, Giovanni; Pettazzoni, Piergiorgio; Pizzimenti, Stefania; Rossi, Federica; Gigliotti, Casimiro Luca; Ciamporcero, Eric Stefano; Daga, Martina; Barrera, Giuseppina

    2014-01-01

    Nanotechnology involves the engineering of functional systems at nanoscale, thus being attractive for disciplines ranging from materials science to biomedicine. One of the most active research areas of the nanotechnology is nanomedicine, which applies nanotechnology to highly specific medical interventions for prevention, diagnosis, and treatment of diseases, including cancer disease. Over the past two decades, the rapid developments in nanotechnology have allowed the incorporation of multiple therapeutic, sensing, and targeting agents into nanoparticles, for detection, prevention, and treatment of cancer diseases. Nanoparticles offer many advantages as drug carrier systems since they can improve the solubility of poorly water-soluble drugs, modify pharmacokinetics, increase drug half-life by reducing immunogenicity, improve bioavailability, and diminish drug metabolism. They can also enable a tunable release of therapeutic compounds and the simultaneous delivery of two or more drugs for combination therapy. In this review, we discuss the recent advances in the use of different types of nanoparticles for systemic and topical drug delivery in the treatment of skin cancer. In particular, the progress in the treatment with nanocarriers of basal cell carcinoma, squamous cell carcinoma, and melanoma has been reported. PMID:25101298

  8. Polymeric nanoparticles modified with fatty acids encapsulating betamethasone for anti-inflammatory treatment.

    PubMed

    Silva, Catarina Oliveira; Rijo, Patrcia; Molpeceres, Jess; Figueiredo, Isabel Vitria; Ascenso, Lia; Fernandes, Ana Sofia; Roberto, Amlcar; Reis, Catarina Pinto

    2015-09-30

    Topical glucocorticosteroids were incorporated into nanocarrier-based formulations, to overcome side effects of conventional formulations and to achieve maximum skin deposition. Nanoparticulate carriers have the potential to prolong the anti-inflammatory effect and provide higher local concentration of drugs, offering a better solution for treating dermatological conditions and improving patient compliance. Nanoparticles were formulated with poly-?-caprolactone as the polymeric core along with stearic acid as the fatty acid, for incorporation of betamethasone-21-acetate. Oleic acid was applied as the coating fatty acid. Improvement of the drug efficacy, and reduction in drug degradation with time in the encapsulated form was examined, while administering it locally through controlled release. Nanoparticles were spherical with mean size of 300 nm and negatively charged surface. Encapsulation efficiency was 90%. Physicochemical stability in aqueous media of the empty and loaded nanoparticles was evaluated for six months. Drug degradation was reduced compared to free drug, after encapsulation into nanoparticles, avoiding the potency decline and promoting a controlled drug release over one month. Fourier transform infrared spectroscopy and thermal analysis confirmed drug entrapment, while cytotoxicity studies performed in vitro on human keratinocytes, Saccharomyces cerevisiae models and Artemia salina, showed a dose-response relationship for nanoparticles and free drug. In all models, drug loaded nanoparticles had a greater inhibitory effect. Nanoparticles increased drug permeation into lipid membranes in vitro. Preliminary safety and permeation studies conducted on rats, showed betamethasone-21-acetate in serum after 48 h application of a gel containing nanoparticles. No skin reactions were observed. In conclusion, the developed nanoparticles may be applied as topical treatment, after encapsulation of betamethasone-21-acetate, as nanoparticles promote prolonged drug release, increase drug stability in aqueous media, reducing drug degradation, and increase drug permeability through lipid membranes. PMID:26222745

  9. The impact of retinol loading and surface charge on the hepatic delivery of lipid nanoparticles.

    PubMed

    Pan, Tai-Long; Wang, Pei-Wen; Hung, Chi-Feng; Aljuffali, Ibrahim A; Dai, You-Shan; Fang, Jia-You

    2016-05-01

    The present work developed lipid nanoparticles to determine whether retinol loading and surface charge influenced liver targeting and biodistribution. Silibinin for treating liver fibrosis was used as the active model. The capability of nanoparticles to suppress hepatic stellate cells (HSCs) was investigated by examining cell viability and α-smooth muscle actin (α-SMA). The biodistribution of the nanocarriers in rats was monitored by real-time and organ bioimaging after an intravenous injection. Silibinin concentration in the organs was detected as well. Anionic nanoparticles showed a mean size of around 260nm, which was greater than that of cationic nanoparticles (about 170nm). The encapsulation percentage of silibinin was >98% for both anionic and cationic nanoparticles. All nanoparticles tested were able to be ingested into HSCs, with no difference between the formulations. The positive nanoparticles produced activated HSC apoptosis much more strongly than negative nanoparticles. The α-SMA suppression exhibited a contrary trend. The nanoparticles rapidly accumulated in the liver and spleen. Retinol incorporation in nanoparticles offers an active targeting approach to the liver via retinol binding protein (RBP). The negatively charged formulation containing retinol achieved higher uptake and longer retention in the liver than the other formulations. Silibinin inclusion in nanoparticles significantly decreased lung deposition and increased liver uptake. The lipid nanosystems promoted silibinin distribution to the liver by 2-3-fold compared to the free control. A better liver-specific selectivity was obtained by retinol-loaded anionic nanocarriers. It is important to optimize the formulations of the lipid nanoparticles for maximizing hepatic targeting. PMID:26901379

  10. Theranostic Upconversion Nanoparticles (I)

    PubMed Central

    Chen, Guanying; Han, Gang

    2013-01-01

    This theme issue provides a comprehensive collection of original research articles on the creation of diverse types of theranostic upconversion nanoparticles, their fundamental interactions in biology, as well as their biophotonic applications in noninvasive diagnostics and therapy. PMID:23606916

  11. Photoemission from metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Protsenko, Igor E.; Uskov, Aleksandr V.

    2012-05-01

    The approach of A M Brodsky and Yu Ya Gurevich is generalized to photoemission from metal nanoparticles at the excitation of a localized plasmon resonance (LPR) in them. The cross section and the probability amplitude of photoemission from a nanoparticle are obtained analytically, taking into account the LPR excitation and the electromagnetic field and photoelectron mass changes at the metal-environment interface. An increase by two orders of magnitude in the photocurrent from a layer of Au nanoparticles to silicon compared to a bulk Au layer is predicted due to an increase in the electromagnetic field strength under the excitation of LPR and due to a significant part of the nanoparticle surface being nonparallel to the incident field polarization. Practicable applications of the results include improving the performance of photocells and photodetectors, and probably reducing the minimum photoeffect time.

  12. Magnetic nanoparticle temperature estimation

    SciTech Connect

    Weaver, John B.; Rauwerdink, Adam M.; Hansen, Eric W.

    2009-05-15

    The authors present a method of measuring the temperature of magnetic nanoparticles that can be adapted to provide in vivo temperature maps. Many of the minimally invasive therapies that promise to reduce health care costs and improve patient outcomes heat tissue to very specific temperatures to be effective. Measurements are required because physiological cooling, primarily blood flow, makes the temperature difficult to predict a priori. The ratio of the fifth and third harmonics of the magnetization generated by magnetic nanoparticles in a sinusoidal field is used to generate a calibration curve and to subsequently estimate the temperature. The calibration curve is obtained by varying the amplitude of the sinusoidal field. The temperature can then be estimated from any subsequent measurement of the ratio. The accuracy was 0.3 deg. K between 20 and 50 deg. C using the current apparatus and half-second measurements. The method is independent of nanoparticle concentration and nanoparticle size distribution.

  13. Renal Clearance of Nanoparticles

    PubMed Central

    Choi, Hak Soo; Liu, Wenhao; Misra, Preeti; Tanaka, Eiichi; Zimmer, John P.; Ipe, Binil Itty; Bawendi, Moungi G.; Frangioni, John V.

    2008-01-01

    SUMMARY The field of nanotechnology holds great promise for the diagnosis and treatment of human disease. However, the size and charge of most nanoparticles preclude their efficient clearance from the body as intact nanoparticles. Without such clearance or their biodegradation into biologically benign components, toxicity is potentially amplified and radiological imaging is hindered. Using quantum dots (QDs) as a model system, we have precisely defined the requirements for renal filtration and urinary excretion of inorganic, metal-containing nanoparticles. Zwitterionic or neutral organic coatings prevented adsorption of serum proteins, which otherwise increased hydrodynamic diameter (HD) by over 15 nm and prevented renal excretion. A final HD smaller than 5.5 nm resulted in rapid and efficient urinary excretion, and elimination of QDs from the body. This study provides a foundation for the design and development of biologically targeted nanoparticles for biomedical applications. PMID:17891134

  14. Herbicidal effects of soil-incorporated wheat.

    PubMed

    Mathiassen, Solvejg K; Kudsk, Per; Mogensen, Betty B

    2006-02-22

    The hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and the benzoxazolinones benzoxazolin-2-one (BOA) and 6-methoxybenzoxazolin-2-one (MBOA) have been identified as important allelochemicals in wheat. This study examines the possibility of exploiting the allelopathic properties of wheat as a weed control strategy by cultivating wheat as a precrop and incorporating plant residues into the soil before the next crop is sown. Different wheat varieties were cultivated in field plots during two seasons in both conventional and organic farming systems. Plants were sampled at various growth stages, and their contents of DIMBOA, MBOA, and BOA were determined by chemical analyses. The wheat samples were incorporated into soil, and the effect on germination and growth of 12 different weed species was examined in pot experiments under controlled conditions. In some cases significant effects were obtained, but the results were inconsistent and the effects were not correlated to the content of DIMBOA, MBOA, and BOA in the incorporated wheat plants. ED50 doses of the pure compounds were estimated in dose-response experiments in Petri dishes, and these turned out to be much higher than the predicted maximum concentrations of DIMBOA, MBOA, and BOA in the soil water following incorporation. The study shows that a prerequisite for exploiting the incorporation of wheat residues as a weed control strategy is the development of wheat varieties with an increased content of allelochemicals. PMID:16478217

  15. Antifungal nanoparticles and surfaces.

    PubMed

    Paulo, Cristiana S O; Vidal, Maria; Ferreira, Lino S

    2010-10-11

    Nosocomial fungal infections, an increasing healthcare concern worldwide, are often associated with medical devices. We have developed antifungal nanoparticle conjugates that can act in suspension or attach to a surface, efficiently killing fungi. For that purpose, we immobilized covalently amphotericin B (AmB), a potent antifungal agent approved by the FDA, widely used in clinical practice and effective against a large spectrum of fungi, into silica nanoparticles. These antifungal nanoparticle conjugates are fungicidal against several strains of Candida sp., mainly by contact. In addition, they can be reused up to 5 cycles without losing their activity. Our results show that the antifungal nanoparticle conjugates are more fungistatic and fungicidal than 10 nm colloidal silver. The antifungal activity of the antifungal nanoparticle conjugates is maintained when they are immobilized on a surface using a chemical adhesive formed by polydopamine. The antifungal nanocoatings have no hemolytic or cytotoxic effect against red blood cells and blood mononuclear cells, respectively. Surfaces coated with these antifungal nanoparticle conjugates can be very useful to render medical devices with antifungal properties. PMID:20845938

  16. Externally modulated theranostic nanoparticles

    PubMed Central

    Urban, Cordula; Urban, Alexander S.; Charron, Heather; Joshi, Amit

    2013-01-01

    Externally modulated nanoparticles comprise a rapidly advancing class of cancer nanotherapeutics, which combine the favorable tumor accumulation of nanoparticles, with external spatio-temporal control on therapy delivery via optical, magnetic, or ultrasound modalities. The local control on therapy enables higher tumor treatment efficacy, while simultaneously reducing off-target effects. The nanoparticle interactions with external fields have an additional advantage of frequently generating an imaging signal, and thus such agents provide theranostic (both diagnostic and therapeutic) capabilities. In this review, we classify the emerging externally modulated theranostic nanoparticles according to the mode of external control and describe the physiochemical mechanisms underlying the external control of therapy, and illustrate the major embodiments of nanoparticles in each class with proven biological efficacy: (I) electromagnetic radiation in visible and near-infrared range is being exploited for gold based and carbon nanostructures with tunable surface plasmon resonance (SPR) for imaging and photothermal therapy (PTT) of cancer, photochemistry based manipulations are employed for light sensitive liposomes and porphyrin based nanoparticles; (II) Magnetic field based manipulations are being developed for iron-oxide based nanostructures for magnetic resonance imaging (MRI) and magnetothermal therapy; (III) ultrasound based methods are primarily being employed to increase delivery of conventional drugs and nanotherapeutics to tumor sites. PMID:24834381

  17. Genetic incorporation of recycled unnatural amino acids.

    PubMed

    Ko, Wooseok; Kim, Sanggil; Jo, Kyubong; Lee, Hyun Soo

    2016-02-01

    The genetic incorporation of unnatural amino acids (UAAs) into proteins has been a useful tool for protein engineering. However, most UAAs are expensive, and the method requires a high concentration of UAAs, which has been a drawback of the technology, especially for large-scale applications. To address this problem, a method to recycle cultured UAAs was developed. The method is based on recycling a culture medium containing the UAA, in which some of essential nutrients were resupplemented after each culture cycle, and induction of protein expression was controlled with glucose. Under optimal conditions, five UAAs were recycled for up to seven rounds of expression without a decrease in expression level, cell density, or incorporation fidelity. This method can generally be applied to other UAAs; therefore, it is useful for reducing the cost of UAAs for genetic incorporation and helpful for expanding the use of the technology to industrial applications. PMID:26358464

  18. Activators generated by electron transfer for atom transfer radical polymerization of styrene in the presence of mesoporous silica nanoparticles

    SciTech Connect

    Khezri, Khezrollah; Roghani-Mamaqani, Hossein

    2014-11-15

    Graphical abstract: Effect of mesoporous silica nanoparticles (MCM-41) on the activator generated by electron transfer for atom transfer radical polymerization (AGET ATRP) is investigated. Decrement of conversion and number average molecular weight and also increment of polydispersity index (PDI) values are three main results of addition of MCM-41 nanoparticles. Incorporation of MCM-41 nanoparticles in the polystyrene matrix can clearly increase thermal stability and decrease glass transition temperature of the nanocomposites. - Highlights: • Spherical morphology, hexagonal structure, and high surface area with regular pore diameters of the synthesized MCM-41 nanoparticles are examined. • AGET ATRP of styrene in the presence of MCM-41 nanoparticles is performed. • Effect of MCM-41 nanoparticles addition on the polymerization rate, conversion and molecular weights of the products are discussed. • Improvement in thermal stability of the nanocomposites and decreasing T{sub g} values was also observed by incorporation of MCM-41 nanoparticles. - Abstract: Activator generated by electron transfer for atom transfer radical polymerization was employed to synthesize well-defined mesoporous silica nanoparticles/polystyrene composites. Inherent features of spherical mesoporous silica nanoparticles were evaluated by nitrogen adsorption/desorption isotherm, X-ray diffraction and scanning electron microscopy analysis techniques. Conversion and molecular weight evaluations were carried out using gas and size exclusion chromatography respectively. By the addition of only 3 wt% mesoporous silica nanoparticles, conversion decreases from 81 to 58%. Similarly, number average molecular weight decreases from 17,116 to 12,798 g mol{sup −1}. However, polydispersity index (PDI) values increases from 1.24 to 1.58. A peak around 4.1–4.2 ppm at proton nuclear magnetic resonance spectroscopy results clearly confirms the living nature of the polymerization. Thermogravimetric analysis shows that thermal stability of the nanocomposites increases by adding nanoparticles content. Decrease of glass transition temperature is also demonstrated by the addition of 3 wt% of silica nanoparticles according to the differential scanning calorimetry results.

  19. Therapy for incorporated radionuclides: scope and need

    SciTech Connect

    Smith, V.H.

    1981-03-01

    In the United States the recent termination of funding for research on therapy for incorporated radionuclides has virtually halted progress on improved or new agents and procedures for removing radioactivity from the body. Research was eliminated, but is still needed on new removal agents, improved delivery system, in vitro test systems, and the toxicology of treatments. For many radionuclides, no adequate therapy exists. The relationship between radionuclide removal and reduction in cancer risk is still unanswered. Without proper research support, needed improvements in the treatment for incorporated radionuclides in the US are uncertain.

  20. Incorporating Duration Information in Activity Recognition

    NASA Astrophysics Data System (ADS)

    Chaurasia, Priyanka; Scotney, Bryan; McClean, Sally; Zhang, Shuai; Nugent, Chris

    Activity recognition has become a key issue in smart home environments. The problem involves learning high level activities from low level sensor data. Activity recognition can depend on several variables; one such variable is duration of engagement with sensorised items or duration of intervals between sensor activations that can provide useful information about personal behaviour. In this paper a probabilistic learning algorithm is proposed that incorporates episode, time and duration information to determine inhabitant identity and the activity being undertaken from low level sensor data. Our results verify that incorporating duration information consistently improves the accuracy.

  1. Nanoparticle flotation collectors III: the role of nanoparticle diameter.

    PubMed

    Yang, Songtao; Pelton, Robert; Montgomery, Miles; Cui, Yuguo

    2012-09-26

    The ability of polystyrene nanoparticles to promote glass bead flotation was measured as a function of nanoparticle diameter. In all cases, smaller nanoparticles were more effective flotation collectors, even when compared at constant nanoparticle number concentration. The superior performance of smaller particles was explained by two mechanisms, acting in parallel. First, smaller particles deposit more quickly giving more effective flotation in those cases where nanoparticle deposition kinetics is rate determining; the sensitivity of nanoparticle deposition rates to particle size was illustrated by kinetic measurements on a quartz crystal microbalance silica surface. Second, for a given coverage of nanoparticles on the glass beads, the mean distance between neighboring nanoparticle surfaces decreases with particle diameter. We propose that the expansion of the three phase contact line, after initial bead/bubble attachment, is favored with decreasing the distance between neighboring hydrophobic particles. PMID:22871900

  2. Heteroaggregation of cerium oxide nanoparticles and nanoparticles of pyrolyzed biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heteroaggregation with indigenous particles is an important process controlling the mobility of engineered nanomaterials in the environment. We studied heteroaggregation of cerium oxide nanoparticles (n-CeO2), which are widely used commercially, with nanoparticles of pyrogenic carbonaceous material ...

  3. Single-step surface functionalization of polymeric nanoparticles for targeted drug delivery.

    PubMed

    Patil, Yogesh B; Toti, Udaya S; Khdair, Ayman; Ma, Linan; Panyam, Jayanth

    2009-02-01

    Targeted drug delivery using nanocarriers is achieved by functionalizing the carrier surface with a tissue-recognition ligand. Current surface modification methods require tedious and inefficient synthesis and purification steps, and are not easily amenable to incorporating multiple functionalities on a single surface. In this report, we describe a versatile, single-step surface functionalizing technique for polymeric nanoparticles. The technique utilizes the fact that when a diblock copolymer like polylactide-polyethylene glycol (PLA-PEG) is introduced in the oil/water emulsion used in polymeric nanoparticle formulation, the PLA block partitions into the polymer containing organic phase and PEG block partitions into the aqueous phase. Removal of the organic solvent results in the formation of nanoparticles with PEG on the surface. When a PLA-PEG-ligand conjugate is used instead of PLA-PEG copolymer, this technique permits a 'one-pot' fabrication of ligand-functionalized nanoparticles. In the current study, the IAASF approach facilitated the simultaneous incorporation of biotin and folic acid, known tumor-targeting ligands, on drug-loaded nanoparticles in a single step. Incorporation of the ligands on nanoparticles was confirmed by using NMR, surface plasmon resonance, transmission electron microscopy and tumor cell uptake studies. Simultaneous functionalization with both ligands significantly enhanced nanoparticle accumulation in tumors in vivo, and resulted in greatly improved efficacy of paclitaxel-loaded nanoparticles in a mouse xenograft tumor model. This new surface functionalization approach will enable the development of targeting strategies based on the use of multiple ligands on a single surface to target a tissue of interest. PMID:19019427

  4. Incorporating Feminism into Rehabilitation Counselor Education

    ERIC Educational Resources Information Center

    Jeon, Mookyong

    2015-01-01

    Purpose: The author describes how rehabilitation counselor educators can incorporate the feminist perspective in teaching rehabilitation counselors-in-training by exploring history, core values, and training methods of feminism. Method: Based on a literature review, the author compares philosophy and concepts of rehabilitation counseling and

  5. Incorporating Mobile Learning into Athletic Training Education

    ERIC Educational Resources Information Center

    Davie, Emily

    2009-01-01

    Objective: To introduce and present techniques for incorporating mobile learning into athletic training education. Background: The matriculation of digital natives into college has stimulated the identification and development of new teaching and learning strategies. Electronic learning (e-learning), including the use of learning management

  6. TOXICITY OF SEDIMENT-INCORPORATED DRILLING FLUIDS

    EPA Science Inventory

    The 24, 96, or 168-h LC50s of four used drilling fluids or barite incorporated into sediment were determined in toxicity tests with lancelets (Branchiostoma caribaeum), a benthic chordate. The number of lancelets that did not burrow into contaminated sediments was used to calcula...

  7. 49 CFR 572.190 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Register approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES IIsD Side Impact Crash Test... Specifications for the SID-IIsD Small Female Crash Test Dummy, Part 572 Subpart V, July 1, 2008,” consisting...

  8. 49 CFR 572.190 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Register approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES IIsD Side Impact Crash Test... Specifications for the SID-IIsD Small Female Crash Test Dummy, Part 572 Subpart V, July 1, 2008,” consisting...

  9. 49 CFR 572.190 - Incorporated materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Register approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES SID-IIsD Side Impact Crash... Specifications for the SID-IIsD Small Female Crash Test Dummy, Part 572 Subpart V, July 1, 2008,” consisting...

  10. 49 CFR 572.190 - Incorporated materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Register approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES IIsD Side Impact Crash Test... Specifications for the SID-IIsD Small Female Crash Test Dummy, Part 572 Subpart V, July 1, 2008,” consisting...

  11. 49 CFR 572.190 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Register approved the materials incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES SID-IIsD Side Impact Crash... Specifications for the SID-IIsD Small Female Crash Test Dummy, Part 572 Subpart V, July 1, 2008,” consisting...

  12. Semiconducting compounds and devices incorporating same

    DOEpatents

    Marks, Tobin J.; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

    2016-01-19

    Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

  13. Design of Schools to Incorporate Fallout Protection.

    ERIC Educational Resources Information Center

    Folley, Milo D.

    Means are suggested by which a school district may incorporate low-cost fallout protection in a school construction program, through construction of an underground shelter beneath the concrete slab foundation. Ways of controlling distribution and filtering air are discussed. The author also suggests consideration of a completely underground…

  14. INCORPORATING INORGANIC FERTILIZER INTO PERENNIAL GRASSLANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inorganic fertilizers can greatly increase forage yields where soil is deficient in essential plant nutrients; but the usual practice of surface applying fertilizers on pastures allows nutrients to be transported from fields in runoff, while much of the ammonia-N volatilizes. Incorporating fertiliz...

  15. Incorporating "Lesson Study" in Teacher Preparation

    ERIC Educational Resources Information Center

    Cohan, Audrey; Honigsfeld, Andrea

    2006-01-01

    This paper describes two teacher educators' practice of incorporating "jugyoun kenkyuu"--the Japanese lesson study approach--in teacher preparation programs. To ascertain the effectiveness of using this approach in undergraduate and graduate education programs, the authors conducted a research study among 17 undergraduate students and 51 graduate…

  16. Combined cycle power plant incorporating coal gasification

    DOEpatents

    Liljedahl, Gregory N. (Tariffville, CT); Moffat, Bruce K. (Simsbury, CT)

    1981-01-01

    A combined cycle power plant incorporating a coal gasifier as the energy source. The gases leaving the coal gasifier pass through a liquid couplant heat exchanger before being used to drive a gas turbine. The exhaust gases of the gas turbine are used to generate both high pressure and low pressure steam for driving a steam turbine, before being exhausted to the atmosphere.

  17. Incorporating Engineering Design Challenges into STEM Courses

    ERIC Educational Resources Information Center

    Householder, Daniel L., Ed.; Hailey, Christine E., Ed.

    2012-01-01

    Successful strategies for incorporating engineering design challenges into science, technology, engineering, and mathematics (STEM) courses in American high schools are presented in this paper. The developers have taken the position that engineering design experiences should be an important component of the high school education of all American…

  18. The Incorporation and Abjection of Official Knowledge

    ERIC Educational Resources Information Center

    Kearl, Benjamin Kelsey

    2012-01-01

    In this essay, the author analyzes two theoretical perspectives--incorporation and abjection--that inform official knowledge generally and high school American history textbooks specifically. While contemporary textbooks increasingly depict the experiences of historically marginalized groups such as women, African Americans, Latinos, American

  19. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Incorporated materials. 572.30 Section 572.30 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III Test Dummy ...

  20. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Incorporated materials. 572.40 Section 572.40 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Dummy...

  1. Identification, Introjection, Incorporation, Internalization: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Identification, introjection, incorporation, and internalization dealt with the same basic process according to S. Freud. The process has been discussed and researched in many and varied personal-social contexts. There have been two general areas of concern: identification for positive reasons (often called developmental) and identification for…

  2. Identification, Introjection, Incorporation, Internalization: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Identification, introjection, incorporation, and internalization dealt with the same basic process according to S. Freud. The process has been discussed and researched in many and varied personal-social contexts. There have been two general areas of concern: identification for positive reasons (often called developmental) and identification for

  3. Incorporation of National Universities in Japan

    ERIC Educational Resources Information Center

    Oba, Jun

    2007-01-01

    In April 2004, Japanese national universities were incorporated and became much more autonomous from the government in their operations. Their managerial structure was realigned--placing the president at the centre of the decision-making process, and with the participation of external persons--to be more responsive to the changing needs of

  4. Semiconducting compounds and devices incorporating same

    SciTech Connect

    Marks, Tobin J; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

    2014-06-17

    Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

  5. Incorporating Learning into the Cognitive Assessment Framework

    ERIC Educational Resources Information Center

    Studer, Cassandra; Junker, Brian; Chan, Helen

    2012-01-01

    The authors aimed to incorporate learning into the cognitive assessment framework that exists for static assessment data. In order to accomplish this, they derive a common likelihood function for dynamic models and introduce Parameter Driven Process for Change + Cognitive Diagnosis Model (PDPC + CDM), a dynamic model which tracks learning

  6. Incorporating Mobile Learning into Athletic Training Education

    ERIC Educational Resources Information Center

    Davie, Emily

    2009-01-01

    Objective: To introduce and present techniques for incorporating mobile learning into athletic training education. Background: The matriculation of digital natives into college has stimulated the identification and development of new teaching and learning strategies. Electronic learning (e-learning), including the use of learning management…

  7. Incorporating PACER into an Inclusive Basketball Unit

    ERIC Educational Resources Information Center

    Cervantes, Carlos M.; Cohen, Rona; Hersman, Bethany L.; Barrett, Tim

    2007-01-01

    Cooperative learning is an instructional method designed to teach students to work together in small, structured, heterogeneous teams to achieve a common goal. The Performer and Coach Earn Rewards (PACER) system is a new way to incorporate cooperative learning in the gymnasium. It consists of six components that help teachers to introduce new

  8. MEASUREMENT OF NANOPARTICLES IN WATER

    EPA Science Inventory

    Measuring nanoparticles in water differs from traditional dissolved solute measurement in several ways. The most salient difference is that nanoparticles are colloids rather than solutes and therefore are subject to the interparticle interactions (mainly electrostatic and Van de...

  9. Direct hierarchical assembly of nanoparticles

    DOEpatents

    Xu, Ting; Zhao, Yue; Thorkelsson, Kari

    2014-07-22

    The present invention provides hierarchical assemblies of a block copolymer, a bifunctional linking compound and a nanoparticle. The block copolymers form one micro-domain and the nanoparticles another micro-domain.

  10. Stabilization of retinol through incorporation into liposomes.

    PubMed

    Lee, Seung-Cheol; Yuk, Hyun-Gyun; Lee, Dong-Hoon; Lee, Kyung-Eun; Hwang, Yong-Il; Ludescher, Richard D

    2002-07-31

    Chemical and photochemical processes during storage and preparation rapidly degrade retinol, the most active form of vitamin A. Therefore, the efficacy of incorporation into liposomes in order to modulate the kinetics of retinol degradation was investigated. Retinol was readily incorporated into multilamellar liposomes that were prepared from soybean phosphatidylcholine; the extent of the incorporation was 98.14 +/- 0.93% at pH 9.0 at a ratio of 0.01 : 1 (wt : wt) retinol : phospholipid. It was only marginally lower at higher retinol concentrations. The pH of the hydration buffer had a small effect. The incorporation efficiency ranged from 99.25 +/- 0.47% at pH 3 to 97.45 +/- 1.13% at pH 11. The time course of the retinol degradation in the aqueous solution in liposomes was compared to that of free retinol and free retinol with alpha-tocopherol under a variety of conditions of pH (3, 7, and 11), temperature (4, 25, 37, and 50 degrees ), and light exposure (dark, visible, and UV). The retinol that was incorporated into the liposomes degraded significantly slower than the free retinol or retinol with alpha-tocopherol at pH 7 and 11. At pH 3, where the free retinol degrades rapidly, the degradation kinetics were similar in liposomes and the presence of alpha-tocopherol. At pH 7.0 and 4 degrees in the light, for example, free aqueous retinol was completely degraded within 2 days, while only 20% of the retinol in the liposomes were degraded after 8 days. In general, the protective effect of the liposome incorporation was greater at low temperatures, at neutral and high pH, and in the dark. The results suggest that protection is greater in the solid, gel phase than in the fluid liquid crystalline phase lipids. These results indicate that the incorporation into liposomes can extend the shelf-life of retinol under a variety of conditions of temperature, pH, and ambient light conditions. PMID:12296993

  11. Direct and continuous synthesis of VO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Powell, M. J.; Marchand, P.; Denis, C. J.; Bear, J. C.; Darr, J. A.; Parkin, I. P.

    2015-11-01

    Monoclinic VO2 nanoparticles are of interest due to the material's thermochromic properties, however, direct synthesis routes to VO2 nanoparticles are often inaccessible due to the high synthesis temperatures or long reaction times required. Herein, we present a two-step synthesis route for the preparation of monoclinic VO2 nanoparticles using Continuous Hydrothermal Flow Synthesis (CHFS) followed by a short post heat treatment step. A range of particle sizes, dependent on synthesis conditions, were produced from 50 to 200 nm by varying reaction temperatures and the residence times in the process. The nanoparticles were characterised by powder X-ray diffraction, Raman and UV/Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The nanoparticles were highly crystalline with rod and sphere-like morphologies present in TEM micrographs, with the size of both the rod and spherical particles being highly dependent on both reaction temperature and residence time. SEM micrographs showed the surface of the powders produced from the CHFS process to be highly uniform. The samples were given a short post synthesis heat treatment to ensure that they were phase pure monoclinic VO2, which led to them exhibiting a large and reversible switch in optical properties (at near-IR wavelengths), which suggests that if such materials can be incorporated into coatings or in composites, they could be used for fenestration in architectural applications.

  12. A nanoparticle-based epigenetic modulator for efficient gene modulation

    NASA Astrophysics Data System (ADS)

    Pongkulapa, Thanapat

    Modulation of gene expression through chromatin remodeling involves epigenetic mechanisms, such as histone acetylation. Acetylation is tightly regulated by two classes of enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs). Molecules that can regulate these enzymes by altering (activating or inhibiting) their functions have become a valuable tool for understanding cell development and diseases. HAT activators, i.e. N-(4-Chloro-(3-trifluoromethyl)phenyl)-2-ethoxybenzamide (CTB), have shown a therapeutic potential for many diseases, including cancer and neurodegeneration. However, these compounds encounter a solubility and a membrane permeability issue, which restricts their full potential for practical usage, especially for in vivo applications. To address this issue, in this work, we developed a nanoparticle-based HAT activator CTB, named Au-CTB, by incorporating a new CTB analogue onto gold nanoparticles (AuNPs) along with a poly(ethylene glycol) moiety and a nuclear localization signal (NLS) peptide to assist with solubility and membrane permeability. We found that our new CTB analogue and Au-CTB could activate HAT activity. Significantly, an increase in potency to activate HAT activity by Au-CTB proved the effectiveness of using the nanoparticle delivery platform. In addition, the versatility of Au-CTB platform permits the attachment of multiple ligands with tunable ratios on the nanoparticle surface via facile surface functionalization of gold nanoparticles. Due to its high delivery efficiency and versatility, Au-CTB can be a powerful platform for applications in epigenetic regulation of gene expression.

  13. Nanoparticle release from nano-silver antimicrobial food containers.

    PubMed

    Echegoyen, Yolanda; Nern, Cristina

    2013-12-01

    Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed to improve their characteristics (flexibility, gas barrier properties, antimicrobial or antioxidant properties, etc.). Among them silver nanoparticles are used because of their antimicrobial effect in many daily life materials, i.e. food packaging. However, there is not any reference to the migration of nanoparticles to the food. In this paper the results of migration studies (with different simulant solutions and times) in three commercial nanosilver plastic food containers are shown. Migration solutions were evaluated by ICP-MS and SEM-EDX analysis and silver in dissolved form and silver as nanoparticles were analyzed, a key aspect for the toxicity. Silver migration was observed for all samples studied, with the total silver migration values ranging between 1.66 and 31.46 ng/cm(2) (lower than the permissible limits). Size and morphology of the silver nanoparticles changed for the different samples (ranging between 10 and 60 nm) and migration of other nanosized materials was also confirmed. PMID:23954768

  14. Direct and continuous synthesis of VO2 nanoparticles.

    PubMed

    Powell, M J; Marchand, P; Denis, C J; Bear, J C; Darr, J A; Parkin, I P

    2015-11-28

    Monoclinic VO2 nanoparticles are of interest due to the material's thermochromic properties, however, direct synthesis routes to VO2 nanoparticles are often inaccessible due to the high synthesis temperatures or long reaction times required. Herein, we present a two-step synthesis route for the preparation of monoclinic VO2 nanoparticles using Continuous Hydrothermal Flow Synthesis (CHFS) followed by a short post heat treatment step. A range of particle sizes, dependent on synthesis conditions, were produced from 50 to 200 nm by varying reaction temperatures and the residence times in the process. The nanoparticles were characterised by powder X-ray diffraction, Raman and UV/Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The nanoparticles were highly crystalline with rod and sphere-like morphologies present in TEM micrographs, with the size of both the rod and spherical particles being highly dependent on both reaction temperature and residence time. SEM micrographs showed the surface of the powders produced from the CHFS process to be highly uniform. The samples were given a short post synthesis heat treatment to ensure that they were phase pure monoclinic VO2, which led to them exhibiting a large and reversible switch in optical properties (at near-IR wavelengths), which suggests that if such materials can be incorporated into coatings or in composites, they could be used for fenestration in architectural applications. PMID:26497868

  15. Temperature-dependent structure of Tb-doped magnetite nanoparticles

    NASA Astrophysics Data System (ADS)

    Rice, Katherine P.; Russek, Stephen E.; Geiss, Roy H.; Shaw, Justin M.; Usselman, Robert J.; Evarts, Eric R.; Silva, Thomas J.; Nembach, Hans T.; Arenholz, Elke; Idzerda, Yves U.

    2015-02-01

    High quality 5 nm cubic Tb-doped magnetite nanoparticles have been synthesized by a wet-chemical method to investigate tailoring of magnetic properties for imaging and biomedical applications. We show that the Tb is incorporated into the octahedral 3+ sites. High-angle annular dark-field microscopy shows that the dopant is well-distributed throughout the particle, and x-ray diffraction measurements show a small lattice parameter shift with the inclusion of a rare-earth dopant. Magnetization and x-ray magnetic circular dichroism data indicate that the Tb spins are unpolarized and weakly coupled to the iron spin lattice at room temperature, and begin to polarize and couple to the iron oxide lattice at temperatures below 50 K. Broadband ferromagnetic resonance measurements show no increase in magnetic damping at room temperature for Tb-doped nanoparticles relative to undoped nanoparticles, further confirming weak coupling between Fe and Tb spins at room temperature. The Gilbert damping constant, ?, is remarkably low for the Tb-doped nanoparticles, with ? = 0.024 0.003. These nanoparticles, which have a large fixed moment, a large fluctuating moment and optically active rare-earth elements, are potential high-relaxivity T1 and T2 MRI agents with integrated optical signatures.

  16. Electrostatic plasmon resonances of metal nanoparticles in stratified geometries

    NASA Astrophysics Data System (ADS)

    Jung, Jesper; Pedersen, Thomas G.; Sndergaard, Thomas; Pedersen, Kjeld

    2010-08-01

    A theoretical electrostatic approach for determination of plasmon eigenresonances and absorption cross section spectra of arbitrarily shaped metal nanoparticles with cylindrical symmetry in stratified geometries is presented. The method is based on a surface integral equation for the surface polarization charge density. From symmetry considerations and by incorporating all effects of the stratified surrounding into the Green's function we show how the three dimensional analysis can be reduced to a single integral over the polar angle along the surface of the metal nanoparticle. The theoretical scheme is exemplified by analyzing silver nanoparticles shaped as spheres, oblate spheroids, and nanodisks in different surroundings involving silicon. The effect of varying the distance between a silver sphere and a silicon surface on plasmonic eigenvalues and absorption cross section spectra is presented. By flattening silver oblate spheroids and nanodisks embedded in a homogenous silicon surrounding it is shown how the fundamental horizontally polarized plasmon resonance can be shifted into the near infrared wavelength range. Also the effect of varying the thickness of thin silicon films with silver nanoparticles embedded is presented. The results indicate that silver nanoparticles embedded in silicon could be interesting for plasmon assisted solar cells.

  17. Antimicrobial properties of hydrated cellulose membranes with silver nanoparticles.

    PubMed

    Jung, Rira; Kim, Yeseul; Kim, Hun-Sik; Jin, Hyoung-Joon

    2009-01-01

    Microbial cellulose membranes have attracted a great deal of attention as novel wound-dressing materials, especially for the healing of skin burns and chronic wounds, because of their high water holding capacity and biocompatibility. However, the high humidity around the wound sometimes allows the growth of bacteria, as well as the regeneration of the tissue. In this study, silver nanoparticles were incorporated into the cellulose membranes via a chemical reduction method using a silver salt, silver nitrate (AgNO(3)) and a reducing agent, sodium borohydride (NaBH(4)). The silver nanoparticles were evenly adsorbed on the overall surface of the cellulose nanofibrils without any local aggregation and had a spherical shape with uniform size (8+/-2 nm) which allowed them to show antimicrobial properties. The interaction between the oxygen in cellulose and silver nanoparticles resulted in the stable adsorption of the silver nanoparticles on cellulose nanofibrils. The cellulose membrane with silver nanoparticles exhibited an antimicrobial activity of more than 99.99% against Escherichia coli and Staphylococcus aureus, so that it could be used as an antimicrobial wound-dressing material for chronic wounds and burns. PMID:19192358

  18. Glucan Particles for Macrophage Targeted Delivery of Nanoparticles

    PubMed Central

    Soto, Ernesto R.; Caras, Abaigeal C.; Kut, Lindsey C.; Castle, Melissa K.; Ostroff, Gary R.

    2012-01-01

    Glucan particles (GPs) are hollow, porous 24??m microspheres derived from the cell walls of Baker's yeast (Saccharomyces cerevisiae). The 1,3-?-glucan outer shell provides for receptor-mediated uptake by phagocytic cells expressing ?-glucan receptors. GPs have been used for macrophage-targeted delivery of soluble payloads (DNA, siRNA, protein, and small molecules) encapsulated inside the hollow GPs via core polyplex and layer-by-layer (LbL) synthetic strategies. In this communication, we report the incorporation of nanoparticles as cores inside GPs (GP-NP) or electrostatically bound to the surface of chemically derivatized GPs (NP-GP). GP nanoparticle formulations benefit from the drug encapsulation properties of NPs and the macrophage-targeting properties of GPs. GP nanoparticle formulations were synthesized using fluorescent anionic polystyrene nanoparticles allowing visualization and quantitation of NP binding and encapsulation. Mesoporous silica nanoparticles (MSNs) containing the chemotherapeutic doxorubicin (Dox) were bound to cationic GPs. Dox-MSN-GPs efficiently delivered Dox into GP phagocytic cells resulting in enhanced Dox-mediated growth arrest. PMID:22013535

  19. Temperature-dependent structure of Tb-doped magnetite nanoparticles

    SciTech Connect

    Rice, Katherine P.; Russek, Stephen E. Shaw, Justin M.; Usselman, Robert J.; Evarts, Eric R.; Silva, Thomas J.; Nembach, Hans T.; Geiss, Roy H.; Arenholz, Elke; Idzerda, Yves U.

    2015-02-09

    High quality 5 nm cubic Tb-doped magnetite nanoparticles have been synthesized by a wet-chemical method to investigate tailoring of magnetic properties for imaging and biomedical applications. We show that the Tb is incorporated into the octahedral 3+ sites. High-angle annular dark-field microscopy shows that the dopant is well-distributed throughout the particle, and x-ray diffraction measurements show a small lattice parameter shift with the inclusion of a rare-earth dopant. Magnetization and x-ray magnetic circular dichroism data indicate that the Tb spins are unpolarized and weakly coupled to the iron spin lattice at room temperature, and begin to polarize and couple to the iron oxide lattice at temperatures below 50 K. Broadband ferromagnetic resonance measurements show no increase in magnetic damping at room temperature for Tb-doped nanoparticles relative to undoped nanoparticles, further confirming weak coupling between Fe and Tb spins at room temperature. The Gilbert damping constant, α, is remarkably low for the Tb-doped nanoparticles, with α = 0.024 ± 0.003. These nanoparticles, which have a large fixed moment, a large fluctuating moment and optically active rare-earth elements, are potential high-relaxivity T1 and T2 MRI agents with integrated optical signatures.

  20. Metal nanoparticles triggered persistent negative photoconductivity in silk protein hydrogels.

    PubMed

    Gogurla, Narendar; Sinha, Arun K; Naskar, Deboki; Kundu, Subhas C; Ray, Samit K

    2016-03-31

    Silk protein is a natural biopolymer with intriguing properties, which are attractive for next generation bio-integrated electronic and photonic devices. Here, we demonstrate the negative photoconductive response of Bombyx mori silk protein fibroin hydrogels, triggered by Au nanoparticles. The room temperature electrical conductivity of Au-silk hydrogels is found to be enhanced with the incorporation of Au nanoparticles over the control sample, due to the increased charge transporting networks within the hydrogel. Au-silk lateral photoconductor devices show a unique negative photoconductive response under an illumination of 325 nm, with excitation energy higher than the characteristic metal plasmon resonance band. The enhanced photoconductance yield in the hydrogels over the silk protein is attributed to the photo-oxidation of amino groups in the β-pleated sheets of the silk around the Au nanoparticles followed by the breaking of charge transport networks. The Au-silk nanocomposite does not show any photoresponse under visible illumination because of the localization of excited charges in Au nanoparticles. The negative photoconductive response of hybrid Au-silk under UV illumination may pave the way towards the utilization of silk for future bio-photonic devices using metal nanoparticle platforms. PMID:26996157