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 polymeric nanoparticles into solid dosage forms

    Microsoft Academic Search

    Christoph Schmidt; Roland Bodmeier

    1999-01-01

    Besides parenteral delivery, polymeric nanoparticles have been used for oral drug delivery. In this study, model polymeric nanoparticles (aqueous colloidal polymer dispersions: Eudragit® RL 30D, L 30D, NE 30D, or Aquacoat®) with different physicochemical properties were incorporated into various solid dosage forms (granules, tablets, pellets or films). The compatibility of the nanoparticles with commonly used tabletting excipients and the redispersibility

  3. Metal-Insulating-Semi-Incorporation of Silicon Nanoparticles into

    E-print Network

    Metal-Insulating-Semi- Conductor Incorporation of Silicon Nanoparticles into Silicon Based Solar material layers create an electrical field. · Middle insulating layer (I) absorbs light and produces charge nanoparticles as insulating layer with aluminum contact on N+ type silicon doped wafer. · Diode-like behavior

  4. Inorganic-organic materials incorporating alumoxane nanoparticles

    Microsoft Academic Search

    Cullen Taylor Vogelson

    2000-01-01

    Chemically functionalized alumina nanoparticles (carboxylate-alumoxanes) are used as the inorganic component of a new class of inorganic-organic material. Lysine- or para-hydroxybenzoic acid-derivatized alumoxanes are prepared from the reaction of boehmite, [Al(O)(OH)]n, with the appropriate carboxylic acid. The peripheral hydroxides and amines of these alumoxanes react directly with DER 332 epoxide to form a hybrid material, or in the presence of

  5. CCMR: Electrospun Fibers Incorporating pH-Sensitive Nanoparticles

    NSDL National Science Digital Library

    Buttaro, Larissa

    2009-08-15

    This research focuses on the incorporation of pH-sensitive nanoparticles into electrospun fibers to function as a sweat monitoring device. In order to determine how fiber size effects the relationship between nanoparticle dye intensity and pH value, the fibers were electrospun at three different speeds: 0.03 mL/hr, 0.3 mL/hr and 0.3 mL/min. These speeds produced fibers of approximately 1.3 ?m, 1.8 ?m, and 9.5 ?m in diameter, respectively. The research found that nanoparticles with smaller fibers are more sensitive to pH change than larger fibers.

  6. Kaempferol glycosides from Siparuna apiosyce.

    PubMed

    Leitão, G G; Soares, S S; Brito, T D; Delle Monache, F

    2000-11-01

    The kaempferol derivative 3,7-di-O-methyl-4'-O-beta-[alpha rhamnosyl (1 --> 6)]-glucopyranoside (siparunoside) was isolated from the leaves of Sparuna apiosyce. Its structure was established by extensive NMR studies. The alkaloids reticuline and liriodenine were also isolated from the leaves along with the kaempferol derivative tiliroside. Benzylisoquinoline alkaloids were isolated from the wood (liriodenine) and wood bark (liriodenine, laurotetanine, N-methyl-laurotetanine, reticuline), together with a mixture of cis and trans-N-feruloyltyramines. 3,7,4'-tri-O-methylkaempferol was isolated from all organs. PMID:11130680

  7. Nanoparticle incorporation of melittin reduces sperm and vaginal epithelium cytotoxicity.

    PubMed

    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 µM 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 µM (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 µM. 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 µM (p<0.001) and were toxic to sperm at equivalent melittin concentrations ?40 µM (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

  8. 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 µM 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 µM (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 µM. 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 µM (p<0.001) and were toxic to sperm at equivalent melittin concentrations ?40 µM (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

  9. 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 51–77% total yields from kaempferol.

  10. Potassium niobate nanoscrolls incorporating rhodium hydroxide nanoparticles for photocatalytic hydrogen evolution

    E-print Network

    Potassium niobate nanoscrolls incorporating rhodium hydroxide nanoparticles for photocatalytic November 2008 DOI: 10.1039/b812003j Well-dispersed rhodium trihydroxide nanoparticles (below 1 nm) wereNb6O17. In order to incorporate rhodium hydroxide, the colloidal suspension was combined

  11. 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

  12. Kaempferol Exhibits Progestogenic Effects in Ovariectomized Rats

    PubMed Central

    Toh, May Fern; Mendonca, Emma; Eddie, Sharon L.; Endsley, Michael P.; Lantvit, Daniel D.; Petukhov, Pavel A.; Burdette, Joanna E.

    2015-01-01

    Objective Progesterone (P4) plays a central role in women's health. Synthetic progestins are used clinically in hormone replacement therapy (HRT), oral contraceptives, and for the treatment of endometriosis and infertility. Unfortunately, synthetic progestins are associated with side effects, including cardiovascular disease and breast cancer. Botanical dietary supplements are widely consumed for the alleviation of a variety of gynecological issues, but very few studies have characterized natural compounds in terms of their ability to bind to and activate progesterone receptors (PR). Kaempferol is a flavonoid that functions as a non-steroidal selective progesterone receptor modulator (SPRM) in vitro. This study investigated the molecular and physiological effects of kaempferol in the ovariectomized rat uteri. Methods Since genistein is a phytoestrogen that was previously demonstrated to increase uterine weight and proliferation, the ability of kaempferol to block genistein action in the uterus was investigated. Analyses of proliferation, steroid receptor expression, and induction of well-established PR-regulated targets Areg and Hand2 were completed using histological analysis and qPCR gene induction experiments. In addition, kaempferol in silico binding analysis was completed for PR. The activation of estrogen and androgen receptor signalling was determined in vitro. Results Molecular docking analysis confirmed that kaempferol adopts poses that are consistent with occupying the ligand-binding pocket of PRA. Kaempferol induced expression of PR regulated transcriptional targets in the ovariectomized rat uteri, including Hand2 and Areg. Consistent with progesterone-l ke activity, kaempferol attenuated genistein-induced uterine luminal epithelial proliferation without increasing uterine weight. Kaempferol signalled without down regulating PR expression in vitro and in vivo and without activating estrogen and androgen receptors. Conclusion Taken together, these data suggest that kaempferol is a unique natural PR modulator that activates PR signaling in vitro and in vivo without triggering PR degradation.

  13. Quantum dots incorporated magnetic nanoparticles for imaging colon carcinoma cells

    PubMed Central

    2013-01-01

    Background Engineered multifunctional nanoparticles (NPs) have made a tremendous impact on the biomedical sciences, with advances in imaging, sensing and bioseparation. In particular, the combination of optical and magnetic responses through a single particle system allows us to serve as novel multimodal molecular imaging contrast agents in clinical settings. Despite of essential medical imaging modalities and of significant clinical application, only few nanocomposites have been developed with dual imaging contrast. A new method for preparing quantum dots (QDs) incorporated magnetic nanoparticles (MNPs) based on layer-by-layer (LbL) self-assembly techniques have developed and used for cancer cells imaging. Methods Here, citrate - capped negatively charged Fe3O4 NPs were prepared and coated with positively - charged hexadecyltrimethyl ammonium bromide (CTAB). Then, thiol - capped negatively charged CdTe QDs were electrostatically bound with CTAB. Morphological, optical and magnetic properties of the fluorescent magnetic nanoparticles (FMNPs) were characterized. Prepared FMNPs were additionally conjugated with hCC49 antibodies fragment antigen binding (Fab) having binding affinity to sialylated sugar chain of TAG-72 region of LS174T cancer cells, which was prepared silkworm expression system, and then were used for imaging colon carcinoma cells. Results The prepared nanocomposites were magnetically responsive and fluorescent, simultaneously that are useful for efficient cellular imaging, optical sensing and magnetic separation. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) revealed that the particle size is around 50 nm in diameter with inner magnetic core and outer CdTe QDs core-shell structure. Cytotoxicity test of prepared FMNPs indicates high viability in Vero cells. NPs conjugated with anti cancer antibodies were successfully labeled on colon carcinoma cells (LS174) in vitro and showed significant specificity to target cells. Conclusion The present report demonstrates a simple synthesis of CdTe QDs-Fe3O4 NPs. The surface of the prepared FMNPs was enabled simple conjugation to monoclonal antibodies by electrostatic interaction. This property further extended their in vitro applications as cellular imaging contrast agents. Such labeling of cells with new fluorescent-magneto nanoprobes for living detection is of interest to various biomedical applications and has demonstrated the potential for future medical use. PMID:23957878

  14. Cisplatin-incorporated hyaluronic acid nanoparticles based on ion-complex formation.

    PubMed

    Jeong, Young-Il; Kim, Seong-Taek; Jin, Shu-Guang; Ryu, Hyang-Hwa; Jin, Yong-Hao; Jung, Tae-Young; Kim, In-Young; Jung, Shin

    2008-03-01

    The aim of this study is to prepare cisplatin-incorporated nanoparticles based on ion complex formation between hyaluronic acid (HA) and cisplatin for antitumor drug delivery. To prepare nanoparticles using HA, bulk HA was degraded by hyaluronidases (HAses). Cisplatin-incorporated HA nanoparticles were prepared by mixing cisplatin with an aqueous solution of HA and then the nanoparticle solution was dialyzed to remove trace elements. Since glioma tumor cell lines are able to secrete HAse, extracts from U343MG and U87MG cell lines were used to test the release of cisplatin from the nanoparticles. The morphological observation of the cisplatin-incorporated nanoparticles showed that they had spherical shapes with a particle size around 100-200 nm. The loading efficiency of cisplatin in the nanoparticles was about 67-81% (w/w) and cisplatin was continuously released from the nanoparticles for 4 days. Especially, the release rate of cisplatin from the nanoparticles increased when HAse was added to the release medium. In the results of the HA zymography, the U343MG cell line secreted HAse, while the U87MG cell line did not. When the extracts from U343MG were added to the release medium, the release rate of cisplatin was slightly increased, while the extracts from U87MG did not significantly affect the release rate of cisplatin. In conclusion, cisplatin-incorporated nanoparticles have sufficiently small particle sizes to use as a drug targeting system. The release of cisplatin from the nanoparticles was responsive to the secretion of HAse. These nanoparticles are suitable vehicles for an antitumor drug targeting system. PMID:17674407

  15. A magnetic poly(dimethylesiloxane) composite membrane incorporated with uniformly dispersed, coated iron oxide nanoparticles

    Microsoft Academic Search

    Luna Cheng; Mu Chiao

    2010-01-01

    We report a new magnetic polymer membrane for MEMS application. The polymeric magnetic composite has coated iron oxide nanoparticles incorporated in a polydimethylsiloxane (PDMS) matrix. Existing magnetic polymeric materials have particle agglomeration problems, which result in rough surfaces and uneven mechanical and optical properties. We show that the use of iron oxide nanoparticles (10 nm in diameter) with fatty acid

  16. 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 ?-mercaptoethanol (?-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 ?-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes. PMID:25558927

  17. 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 ?-mercaptoethanol (?-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 ?-ME denaturation are promising nanocarriers for hydrophobic substances from chemotherapy drugs to imaging probes.

  18. Tuning of optical properties of PMMA by incorporating silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Alisha, Rozra, Jyoti; Saini, Isha; Sharma, Annu; Sharma, Pawan

    2012-06-01

    Nanocomposite films of Poly (methylmethacrylate) filled with different concentration of silver nanoparticles were prepared by ex-situ method. Firstly, silver nanoparticles were obtained by reducing the aqueous solution of silver nitrate with sodium borohydride then Ag/PMMA films were prepared by mixing colloidal solution of silver nanoparticles with solution of polymer. From absorption and specular reflection spectra, the optical band gap and refractive index (n) have been calculated. The decrease in optical bandgap and increase in refractive index has been indicative of the modifications in optical band structure of the PMMA matrix.

  19. Comparison of post-detonation combustion in explosives incorporating aluminum nanoparticles: Influence of the passivation layer

    NASA Astrophysics Data System (ADS)

    Lewis, W. K.; Rumchik, C. G.; Smith, M. J.; Fernando, K. A. S.; Crouse, C. A.; Spowart, J. E.; Guliants, E. A.; Bunker, C. E.

    2013-01-01

    Aluminum nanoparticles and explosive formulations that incorporate them have been a subject of ongoing interest due to the potential of aluminum particles to dramatically increase energy content relative to conventional organic explosives. We have used time-resolved atomic and molecular emission spectroscopy to monitor the combustion of aluminum nanoparticles within the overall chemical dynamics of post-detonation fireballs. We have studied the energy release dynamics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) charges incorporating three types of aluminum nanoparticles: commercial oxide-passivated nanoparticles, oleic acid-capped aluminum nanoparticles (AlOA), and nanoparticles in which the oxide shell of the particle has been functionalized with an acrylic monomer and copolymerized into a fluorinated acrylic matrix (AlFA). The results indicate that the commercial nanoparticles and the AlFA nanoparticles are oxidized at a similar rate, while the AlOA nanoparticles combust more quickly. This is most likely due to the fact that the commercial nano-Al and the AlFA particles are both oxide-passivated, while the AlOA particles are protected by an organic shell that is more easily compromised than an oxide layer. The peak fireball temperatures for RDX charges containing 20 wt. % of commercial nano-Al, AlFA, or AlOA were ˜3900 K, ˜3400 K, and ˜4500 K, respectively.

  20. Silver nanoparticles incorporated onto ordered mesoporous silica from Tollen's reagent

    NASA Astrophysics Data System (ADS)

    Zienkiewicz-Strza?ka, M.; Pasieczna-Patkowska, S.; Kozak, M.; Pikus, S.

    2013-02-01

    Noble metal nanostructures supported on mesoporous silica are bridge between traditional silica adsorbents and modern catalysts. In this work the Ag/SBA-15 mesoporous materials were synthesized and characterized. Various forms of nanosilver supported on ordered mesoporous template have been successfully obtained via proposed procedures. In all synthesized materials, Tollen's reagent (diammine silver complex [Ag(NH3)2]+) was used as a silver source. Silver nanoparticles were prepared by reduction of ammoniacal silver complex by formaldehyde in the solution of stabilizer. After reduction, Ag nanoparticles could be deposited on SBA-15, or added during traditional synthesis of SBA-15 giving silver or silver chloride nanoparticles in the combination with porous silica. Silver nanostructures as nanoparticles or nanowires were also embedded onto the SBA-15 by incipient wetness impregnation of silver ions. Absorbed silver ions were next reduced under hydrogen at high temperature. There are many advantages of utilized ammoniacal silver complex as a silver source. Proposed method is capable to synthesis of various metal nanostructures with controlled composition and morphology. The silver ammonia complex is composed of two ions surrounding and protecting the central silver ion, so it is possible to obtain very small nanoparticles using simple approach without any functionalization of external and internal surface of SBA-15. This approach allows obtaining greatly small silver nanoparticles on SBA-15 (4 nm) or nanowires depending on the metal loading amount. Moreover, the colloidal silver solution prepared from Tollen's reagent, in the presence of triblock copolymer, remains stable for a long time. Reduction of Tollen's reagent to silver colloidal solution seems to be efficient, fast and interesting approach for the preparation of supported silver nanostructures Obtained samples were characterized by powder X-ray diffraction, small angle X-ray scattering (SAXS), UV-vis spectroscopy, transmission electron microscopy (TEM), nitrogen adsorption-desorption isotherms and photoacoustic spectroscopy (PAS).

  1. Thermal conductivity measurement of organic solvents incorporated with silver nanoparticle using photothermal techniques

    NASA Astrophysics Data System (ADS)

    Shemeena Basheer, N.; Kumar, B. Rajesh; Kurian, Achamma; George, Sajan D.

    2015-02-01

    The present paper summarizes our recent work on heat transfer of nanofluid in different organic solvents determined using photothermal techniques. UV- Visible absorption spectrum shows an intense surface plasmon absorption peak at 427 nm. TEM indicates the presence of well dispersed silver nanoparticles having spherical morphology with particle size ranging from 10 to13 nm. The experimental results show that thermal conductivity of organic solvents increases with the incorporation of silver nanoparticles.

  2. Copper nanoparticle incorporated plasmonic organic bulk-heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Zhihai; Lee, Seung Yong; Lee, Eun-Cheol

    2014-12-01

    By embedding copper nanoparticles into poly(3,4-thylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layers, the power conversion efficiency of organic bulk-heterojunction solar cell using poly(3-hexylthiophene) (P3HT) was increased from 3.58% to 3.96%, and that of the device based on poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  3. Kaempferol Downregulates Insulin-like Growth Factor-I Receptor and ErbB3 Signaling in HT-29 Human Colon Cancer Cells

    PubMed Central

    Lee, Hyun Sook; Cho, Han Jin; Kwon, Gyoo Taik; Park, Jung Han Yoon

    2014-01-01

    Background: Novel dietary agents for colon cancer prevention and therapy are desired. Kaempferol, a flavonol, has been reported to possess anticancer activity. However, little is known about the molecular mechanisms of the anticancer effects of kaempferol. The aim of this study was to determine the inhibitory effect of kaempferol on growth factor-induced proliferation and to elucidate its underlying mechanisms in the HT-29 human colon cancer cell line. Methods: To assess the effects of kaempferol and/or growth factors [insulin-like growth factor (IGF)-I and heregulin (HRG)-?], cells were cultured with or without 60 ?mol/L kaempferol and/or 10 nmol/L IGF-I or 20 ?g/L HRG-?. Cell proliferation, DNA synthesis, and apoptosis were determined by a cell viability assay, a [3H]thymidine incorporation assay, and Annexin-V staining, respectively. Western blotting, immunoprecipitation, and an in vitro kinase assay were conducted to evaluate expression and activation of various signaling molecules involved in the IGF-I receptor (IGF-IR) and ErbB3 signaling pathways. Results: IGF-I and HRG-? stimulated HT-29 cell growth but did not abrogate kaempferol-induced growth inhibition and apoptosis. Kaempferol reduced IGF-II secretion, HRG expression and phosphorylation of Akt and extracellular signal-regulated kinase (ERK)-1/2. Kaempferol reduced IGF-I- and HRG-?-induced phosphorylation of the IGF-IR and ErbB3, their association with p85, and phosphatidylinositol 3-kinase (PI3K) activity. Additionally, kaempferol inhibited IGF-I- and HRG-?-induced phosphorylation of Akt and ERK-1/2. Conclusions: The results demonstrate that kaempferol downregulates activation of PI3K/Akt and ERK-1/2 pathways by inhibiting IGF-IR and ErbB3 signaling in HT-29 cells. We suggest that kaempferol could be a useful chemopreventive agent against colon cancer. PMID:25337585

  4. 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

  5. Maximizing dye fluorescence via incorporation of metallic nanoparticles in solution

    NASA Astrophysics Data System (ADS)

    Xu, Yang; Lei, Guangyin; Booker, Annette C.; Linares, Katherine A.; Fleming, Dara L.; Meehan, Kathleen; Lu, Guo-Quan; Love, Nancy G.; Love, Brian J.

    2004-12-01

    Gram-negative bacteria initiate a stress response in which the cells efflux potassium when electrophilic toxins are introduced into their environment. Hence, measurement of K+ concentration in the surrounding water using a fluorescence-based potassium-selective optode has been proposed for environmental and homeland security applications. Unfortunately, the fluorophore commonly used in such an optode is inefficient. Surface enhanced fluorescence (SEF) can be used to increase its fluorescence efficiency, which will improve the sensor's performance. To understand this phenomenon before applying it to the optode system, Rose Bengal (RB), an inexpensive and well characterized dye, in solution with gold and silver nanoparticles was studied. As expected, fluorescence from RB-gold solutions was low since alignment of gold's surface plasmon resonance (SPR) peak and absorption and fluorescence energies in RB favored energy transfer from RB to the gold nanoparticles. The alignment of the silver's SPR peak and the RB transitions favored transfer from silver to RB. SEF was observed in solutions with large dye-to-silver separation. However, little fluorescence was observed when the solution was pumped at the silver's SPR peak. Fluorescence from the dye decreased as dye-to-silver separation decreased. An explanation for these observations is presented; additional research is needed to develop a complete understanding.

  6. Kaempferol and quercetin glycosides from Rubus idaeus L. leaves.

    PubMed

    Gudej, Jan

    2003-01-01

    Quercetin 3-0-beta-D-glucoside (I), quercetin and kaempferol 3-0-beta-D-galactosides (II, III), kaempferol 3-0-beta-L-arabinopyranoside (IV), kaempferol 3-0-beta-D-(6''-E-p-coumaroyl)-glucoside (tiliroside) (V) and methyl gallate (VI) were isolated from Rubus idaeus L. subspecies culture of Norna leaves and fully characterized. PMID:14714861

  7. 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

  8. 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

  9. Synthesis and characterization of Eu(III)-incorporated silica nanoparticles for application to UV-LED.

    PubMed

    Jeong, Yong-Kwang; Sohn, Youngku; Kang, Jun-Gill

    2014-06-01

    A tetrakis(dibenzylmethanido) Eu(III) complex as a ultraviolet (UV) excited phosphor was synthesized, and incorporated with mesoporous silica as core-shell (CS), outer-shell (OS) and intermediate-shell (IS) architectures, using a combination of the self-organization process and the Stöber method. Exciting the Eu(III) complex at UV light produced a strong sensitized red-emission from Eu(III) by energy transfer from the ligand. Phosphor-converted light-emitting diodes (pc-LEDs) were fabricated by casting the powdered complex and the incorporated silica nanoparticles onto a 365-nm InGaN chip, and their optical properties and thermal stability were investigated in terms of the chromaticity index and the intensity decay, respectively. The CS silica nanoparticle casted UV-LED exhibited the best perfomence with strong intensity and excellent thermal stability. PMID:24703666

  10. Sorption, Solubility, Bond Strength and Hardness of Denture Soft Lining Incorporated with Silver Nanoparticles

    PubMed Central

    Chladek, Grzegorz; Kasperski, Jacek; Barszczewska-Rybarek, Izabela; ?mudzki, Jaros?aw

    2013-01-01

    The colonization of denture soft lining material by oral fungi can result in infections and stomatitis of oral tissues. In this study, 0 ppm to 200 ppm of silver nanoparticles was incorporated as an antimicrobial agent into composites to reduce the microbial colonization of lining materials. The effect of silver nanoparticle incorporation into a soft lining material on the sorption, solubility, hardness (on the Shore A scale) and tensile bond strength of the composites was investigated. The data were statistically analyzed using two-way ANOVA and Newman-Keuls post hoc tests or the chi-square Pearson test at the p < 0.05 level. An increase in the nanosilver concentration resulted in a decrease in hardness, an increase in sorption and solubility, a decrease in bond strength and a change in the failure type of the samples. The best combination of bond strength, sorption, solubility and hardness with antifungal efficacy was achieved for silver nanoparticle concentrations ranging from 20 ppm to 40 ppm. These composites did not show properties worse than those of the material without silver nanoparticles and exhibited enhanced in vitro antifungal efficiency. PMID:23271371

  11. Microstructures and tribological properties of PEEK-based nanocomposite coatings incorporating inorganic fullerene-like nanoparticles

    Microsoft Academic Search

    Xianghui Hou; C. X. Shan; Kwang-Leong Choy

    2008-01-01

    The high strength, wear resistance and high operational temperature of polyetheretherketone (PEEK) have attracted increasing interests of this material for tribological applications. The addition of solid lubricant is an effective way to further improve the tribological properties of polymeric materials. In the present work, inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles were incorporated into PEEK coatings with the aim of reducing

  12. 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 50–200 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

  13. 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.

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

    SciTech Connect

    Lucas, Marcel [Los Alamos National Laboratory; Macdonald, Brian A [Los Alamos National Laboratory; Wagner, Gregory L [Los Alamos National Laboratory; Joyce, Steven A [Los Alamos National Laboratory; Rector, Kirk D [Los Alamos National Laboratory

    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.

  15. Synthesis of Cr 2O 3-based nanocomposite coatings with incorporation of inorganic fullerene-like nanoparticles

    Microsoft Academic Search

    Xianghui Hou; Kwang-Leong Choy

    2008-01-01

    The incorporation of inorganic fullerene-like nanoparticles into coating systems is considered an effective method to provide extra functionality and improve the specific properties of matrix coatings. In the present work, inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles have been incorporated into Cr2O3 coatings via a modified aerosol-assisted chemical vapour deposition process (AACVD), for the purpose of reducing friction and improving wear

  16. Biodistribution and in vivo activities of tumor-associated macrophage-targeting nanoparticles incorporated with doxorubicin.

    PubMed

    Niu, Mengmeng; Naguib, Youssef W; Aldayel, Abdulaziz M; Shi, Yan-chun; Hursting, Stephen D; Hersh, Matthew A; Cui, Zhengrong

    2014-12-01

    Tumor-associated macrophages (TAMs) are increasingly considered a viable target for tumor imaging and therapy. Previously, we reported that innovative surface-functionalization of nanoparticles may help target them to TAMs. In this report, using poly(lactic-co-glycolic) acid (PLGA) nanoparticles incorporated with doxorubicin (DOX) (DOX-NPs), we studied the effect of surface-modification of the nanoparticles with mannose and/or acid-sensitive sheddable polyethylene glycol (PEG) on the biodistribution of DOX and the uptake of DOX by TAMs in tumor-bearing mice. We demonstrated that surface-modification of the DOX-NPs with both mannose and acid-sensitive sheddable PEG significantly increased the accumulation of DOX in tumors, enhanced the uptake of the DOX by TAMs, but decreased the distribution of DOX in mononuclear phagocyte system (MPS), such as liver. We also confirmed that the acid-sensitive sheddable PEGylated, mannose-modified DOX-nanoparticles (DOX-AS-M-NPs) targeted TAMs because depletion of TAMs in tumor-bearing mice significantly decreased the accumulation of DOX in tumor tissues. Furthermore, in a B16-F10 tumor-bearing mouse model, we showed that the DOX-AS-M-NPs were significantly more effective than free DOX in controlling tumor growth but had only minimum effect on the macrophage population in mouse liver and spleen. The AS-M-NPs are promising in targeting cytotoxic or macrophage-modulating agents into tumors to improve tumor therapy. PMID:25314115

  17. 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.

  18. Paclitaxel-incorporated nanoparticles using block copolymers composed of poly(ethylene glycol)/poly(3-hydroxyoctanoate)

    PubMed Central

    2014-01-01

    Block copolymers composed of poly(3-hydroxyoctanoate) (PHO) and methoxy poly(ethylene glycol) (PEG) were synthesized to prepare paclitaxel-incorporated nanoparticle for antitumor drug delivery. In a 1H-NMR study, chemical structures of PHO/PEG block copolymers were confirmed and their molecular weight (M.W.) was analyzed with gel permeation chromatography (GPC). Paclitaxel as a model anticancer drug was incorporated into the nanoparticles of PHO/PEG block copolymer. They have spherical shapes and their particle sizes were less than 100 nm. In a 1H-NMR study in D2O, specific peaks of PEG solely appeared while peaks of PHO disappeared, indicating that nanoparticles have core-shell structures. The higher M.W. of PEG decreased loading efficiency and particle size. The higher drug feeding increased drug contents and average size of nanoparticles. In the drug release study, the higher M.W. of PEG block induced the acceleration of drug release rate. The increase in drug contents induced the slow release rate of drug. In an antitumor activity study in vitro, paclitaxel nanoparticles have practically similar anti-proliferation activity against HCT116 human colon carcinoma cells. In an in vivo animal study using HCT116 colon carcinoma cell-bearing mice, paclitaxel nanoparticles have enhanced antitumor activity compared to paclitaxel itself. Therefore, paclitaxel-incorporated nanoparticles of PHO/PEG block copolymer are a promising vehicle for antitumor drug delivery. PMID:25288916

  19. 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.

  20. A magnetic poly(dimethylesiloxane) composite membrane incorporated with uniformly dispersed, coated iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pirmoradi, Fatemeh Nazly; Cheng, Luna; Chiao, Mu

    2010-01-01

    We report a new magnetic polymer membrane for MEMS application. The polymeric magnetic composite has coated iron oxide nanoparticles incorporated in a polydimethylsiloxane (PDMS) matrix. Existing magnetic polymeric materials have particle agglomeration problems, which result in rough surfaces and uneven mechanical and optical properties. We show that the use of iron oxide nanoparticles (10 nm in diameter) with fatty acid and hydrophobic coatings inhibits aggregation of particles in the PDMS polymer matrix. Agglomerated particle sizes in thin-film PDMS composites incorporated with uncoated and coated particles are 51 ± 24 µm and 1.6 ± 0.25 µm, respectively. The PDMS composites exhibit saturation magnetization of 22.8 to 23.94 emu g-1. Stress-strain curves of the composites are characterized by tensile tests. Free-standing magnetic PDMS membranes are fabricated in different sizes from 4 mm to 7 mm in diameter and with the thickness of 35.5 ± 1.5 µm. The membrane of 7 mm diameter achieves deflection of 625 µm in a 0.417 T magnetic field. The magnetic PDMS membranes may be used in micro-pumps and lab-on-a-chip applications.

  1. Effect of formulation factors on incorporation of the hydrophilic peptide dalargin into PLGA and mPEG-PLGA nanoparticles.

    PubMed

    Chen, Y; Wang, F; Benson, H A E

    2008-01-01

    The objective of this study was to examine formulation factors that influence the incorporation of the hydrophilic peptide dalargin into poly(D, L-lactic-co-glycolic acid) (PLGA) and methoxy-polyethylene glycol (mPEG)-PLGA nanoparticles. In particular, the effect of ionic additives and nanoparticle method of preparation on the incorporation of dalargin and resultant nanoparticle properties was investigated. Biodegradable nanoparticles were prepared from mPEG-PLGA and PLGA by both solvent evaporation and solvent diffusion methods with inclusion of ionic additives of dextran sulphate (DS), sulfobutyl ether-beta-cyclodextrin (SB-CD), or sodium dodecyl sulfate (SDS). The resultant nanoparticles were analyzed for their mean particle size and size distribution, zeta-potential, peptide loading, yield, and morphology. The inclusion of ionic additives in the nanoparticle formulation significantly influenced dalargin entrapment efficiency (EE). For example, with the PLGA/SDS formulation EE increased from 13.3% to 91.2% and from 4.1% to 68.6% with the solvent diffusion and evaporation methods, respectively. The inclusion of ionic surfactant SDS has also lead to the formation of smaller size of nanoparticles. Isothermal titration microcalorimetry revealed a strong interaction between dalargin and DS, medium level interaction with SDS, and weak interaction with SB-CD. The results of this study suggest that a strong ionic interaction between peptides and additives may lead to enhanced peptide incorporation but also increased particle size. Intermediate ionic interaction, especially when it is associated with the formation of reversed micelles in a hydrophobic polymer solution, could be used to enhance the incorporation of hydrophilic peptides in PLGA and mPEG-PLGA nanoparticles. PMID:18459172

  2. 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.

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

    SciTech Connect

    Pootawang, Panuphong, E-mail: p.pootawang@gmail.com [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of)] [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of); Saito, Nagahiro; Takai, Osamu [EcoTopia Science and Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)] [EcoTopia Science and Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Lee, Sang Yul [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of)] [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of)

    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? = 35–90°) corresponded to the mesoporous silica and Ag nanocrystal characteristics. Comparing with mesoporous silica prepared by a conventional sol–gel 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.

  4. Impact of magnetite nanoparticle incorporation on optical and electrical properties of nanocomposite LbL assemblies.

    PubMed

    Yashchenok, Alexey M; Gorin, Dmitry A; Badylevich, Mikhail; Serdobintsev, Alexey A; Bedard, Matthieu; Fedorenko, Yanina G; Khomutov, Gennady B; Grigoriev, Dmitri O; Möhwald, Helmuth

    2010-09-21

    Optical and electrical properties of polyelectrolyte/iron oxide nanocomposite planar films on silicon substrates were investigated for different amount of iron oxide nanoparticles incorporated in the films. The nanocomposite assemblies prepared by the layer-by-layer assembly technique were characterized by ellipsometry, atomic force microscopy, and secondary ion mass-spectrometry. Absorption spectra of the films reveal a shift of the optical absorption edge to higher energy when the number of deposited layers decreases. Capacitance-voltage and current-voltage measurements were applied to study the electrical properties of metal-oxide-semiconductor structures prepared by thermal evaporation of gold electrodes on nanocomposite films. The capacitance-voltage measurements show that the dielectric constant of the film increases with the number of deposited layers and the fixed charge and the trapped charge densities have a negative sign. PMID:20602000

  5. 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

  6. 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.

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

    PubMed

    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. PMID:23060604

  8. Methylation of genistein and kaempferol improves their affinities for proteins.

    PubMed

    Cao, Hui; Jing, Xiaohui; Wu, Donghui; Shi, Yujun

    2013-06-01

    Methylation of flavonoids appears to be a simple and effective way to improve metabolic resistance and transport of flavonoids. Serum albumins are major soluble proteins serving as transport proteins for many exogenous compounds. This work in here mainly concerns about the effect of methylation of flavonoids on the affinity for human serum albumin (HSA) and ovalbumin. One isoflavone (genistein) and one flavonol (kaempferol) and their monomethylated derivatives at position 4' (biochanin A and kaempferide) were studied for their affinities for ovalbumin and HSA. The methylation of flavonoids significantly affects the binding process. In general, the methylation of flavonoids improved the affinities for proteins by 2-16 times. This result supports that the methylation of genistein and kaempferol enhanced the transporting ability, which leads to facilitated absorption and greatly increased bioavailability. The methylation increases the hydrophobicity of genistein and kaempferol, and the hydrophobic interaction plays an important role in binding flavonoids to HSA and ovoalbumin. PMID:23311465

  9. 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

  10. 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

  11. 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

  12. 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

  13. Hemoglobin–Albumin Cluster Incorporating a Pt Nanoparticle: Artificial O2 Carrier with Antioxidant Activities

    PubMed Central

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

    2014-01-01

    A covalent core–shell 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 1.1×107 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?=?1.1×107 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

  14. Microfiber coupler based biosensor incorporating a layer of gold nanoparticles with improved sensitivity

    NASA Astrophysics Data System (ADS)

    Semenova, Yuliya; Bo, Lin; Wang, Pengfei; Tian, Furong; Byrne, Hugh; Farrell, Gerald

    2014-05-01

    We studied the effect of a star-shaped gold nanoparticles layer coated on the surface of the microfiber coupler (MFC) on the sensitivity of the embedded MFC biosensor. It is shown that deposition of the layer of star-shaped gold nanoparticles on the MFC sensor surface results in a significantly increased spectral shift (on average 3.05 nm shift compared to a 1.08 nm shift per layer of electrolyte for the sample without the nanoparticles layer). In addition, introducing the nanoparticle layer results in the decrease of the transmission power; measurement of the changes in transmission also could be used as a means for the sensor interrogation.

  15. 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.

  16. Lapatinib-incorporated lipoprotein-like nanoparticles: preparation and a proposed breast cancer-targeting mechanism

    PubMed Central

    Zhang, Li; Zhang, Shuang; Ruan, Shao-bo; Zhang, Qian-yu; He, Qin; Gao, Hui-le

    2014-01-01

    Aim: Lapatinib is a dual inhibitor of EGFR and human epidermal growth factor receptor 2 (HER2), and used to treat advanced breast cancer. To overcome its poor water solubility, we constructed lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs), and evaluated the particle characteristics and possible anti-breast cancer mechanisms. Methods: LTNPs (lapatinib bound to albumin as a core, and egg yolk lecithin forming a lipid corona) were prepared. The particle characteristics were investigated using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The uptake and subcellular localization of LTNPs, as well as the effects of LTNPs on cell cycle were examined in BT-474 human breast cancer cells in vitro. Mice bearing BT-474 subcutaneous xenograft were intravenously injected with coumarin-6 loaded LTNPs (30 mg/kg) to study the targeting mechanisms in vivo. Results: The LTNPs particles were generally spherical but flexible under TEM and AFM, and approximately 62.1 nm in size with a zeta potential of 22.80 mV. In BT-474 cells, uptake of LTNPs was mediated by endosomes through energy-dependent endocytosis involving clathrin-dependent pinocytosis and macropinocytosis, and they could effectively escape from endosomes to the cytoplasm. Treatment of BT-474 cells with LTNPs (20 ?g/mL) induced a significant cell arrest at G0/G1 phase compared with the same concentration of lapatinib suspension. In mice bearing BT-474 xenograft, intravenously injected LTNPs was found to target and accumulate in tumors, and colocalized with HER2 and SPRAC (secreted protein, acidic and rich in cysteine). Conclusion: LTNPs can be taken up into breast cancer cells through specific pathways in vitro, and targeted to breast cancer xenograft in vivo via enhanced permeability and retention effect and SPARC. PMID:24902791

  17. Photosensitizer-incorporated G-quadruplex DNA-functionalized magnetofluorescent nanoparticles for targeted magnetic resonance/fluorescence multimodal imaging and subsequent photodynamic therapy of cancer.

    PubMed

    Yin, Meili; Li, Zhenhua; Liu, Zhen; Ren, Jinsong; Yang, Xinjian; Qu, Xiaogang

    2012-07-01

    A smart heteronanostructure has been constructed for targeted photodynamic therapy and magnetic fluorescent imaging of cancer cells using photosensitizer-incorporated G-quadruplex DNA functionalized magnetic nanoparticles. PMID:22622597

  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. Mechanism of enhanced oral absorption of hydrophilic drug incorporated in hydrophobic nanoparticles.

    PubMed

    Lv, Liang-Zhong; Tong, Chen-Qi; Yu, Jia; Han, Min; Gao, Jian-Qing

    2013-01-01

    Hydroxysafflor yellow A (HSYA) is an effective ingredient of the Chinese herb Carthamus tinctorius L, which has high water solubility and low oral bioavailability. This research aims to develop a hydrophobic nanoparticle that can enhance the oral absorption of HSYA. Transmission electron microscopy and freeze-fracture replication transmission election microscopy showed that the HSYA nanoparticles have an irregular shape and a narrow size distribution. Zonula occludens 1 protein (ZO-1) labeling showed that the nanoparticles with different dilutions produced an opening in the tight junctions of Caco-2 cells without inducing cytotoxicity to the cells. Both enhanced uptake in Caco-2 cells monolayer and increased bioavailability in rats for HSYA nanoparticles indicated that the formulation could improve bioavailability of HSYA significantly after oral administration both in vitro and in vivo. PMID:23935363

  20. 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, E-mail: gangopadhyays@missouri.edu [Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65201 (United States)] [Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65201 (United States)

    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.

  1. 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

  2. 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 5×10(-7) to 1.84×10(-2) M with a low detection limit of 3.7×10(-7) M. The sensor also exhibits good repeatability, long-term stability as well as high selectivity against interfering species. PMID:25499226

  3. ???3-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. ???3-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 ???3-integrin, providing proof of concept in vivo for the first targeted PA - drug delivery agent. PMID:25553103

  4. Photoacoustic molecular imaging of angiogenesis using theranostic ???3-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. ???3-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, ???3-targeted CuNPs hold great promise for the management of skin pathologies with neovascular features.

  5. 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

  6. The effects of incorporation Fe 2 O 3 nanoparticles on tensile and flexural strength of concrete

    Microsoft Academic Search

    Ali Nazari; Shadi Riahi; Shirin Riahi; Seyedeh Fatemeh Shamekhi; A. Khademno

    2010-01-01

    In this Paper, the split tensile and flexural stren gth together with the setting time of concrete by p artial replacement of cement with nano-phase Fe 2O3 particles has been studied. Fe 2O3 nanoparticles with the average diameter of 15 nm were used with four different contents of 0.5%, 0.1%, 1. 5% and 2.0% by weight. The results showed that

  7. 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

  8. 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...

  9. 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 ...

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

    SciTech Connect

    Xiao, Hong-Bo, E-mail: xhbzhb@yahoo.com [College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128 (China)] [College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128 (China); Lu, Xiang-Yang; Sun, Zhi-Liang [Hunan Agricultural University, Changsha 410128 (China)] [Hunan Agricultural University, Changsha 410128 (China); Zhang, Heng-Bo [Furong District Red Cross Hospital, Changsha 410126 (China)] [Furong District Red Cross Hospital, Changsha 410126 (China)

    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.

  11. Rheological and tribological properties of carbon nanotube/thermoplastic nanocomposites incorporating inorganic fullerene-like WS2 nanoparticles.

    PubMed

    Díez-Pascual, Ana M; Naffakh, Mohammed; Marco, Carlos; Ellis, Gary

    2012-07-12

    The rheological and tribological properties of single-walled carbon nanotube (SWCNT)-reinforced poly(phenylene sulphide) (PPS) and poly(ether ether ketone) (PEEK) nanocomposites prepared via melt-extrusion were investigated. The effectiveness of employing a dual-nanofiller strategy combining polyetherimide (PEI)-wrapped SWCNTs with inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles for property enhancement of the resulting hybrid composites was evaluated. Viscoelastic measurements revealed that the complex viscosity ?, storage modulus G', and loss modulus G? increased with SWCNT content. In the low-frequency region, G' and G? became almost independent of frequency at higher SWCNT loadings, suggesting a transition from liquid-like to solid-like behavior. The incorporation of increasing IF-WS2 contents led to a progressive drop in ? and G' due to a lubricant effect. PEEK nanocomposites showed lower percolation threshold than those based on PPS, ascribed to an improved SWCNT dispersion due to the higher affinity between PEI and PEEK. The SWCNTs significantly lowered the wear rate but only slightly reduced the coefficient of friction. Composites with both nanofillers exhibited improved wear behavior, attributed to the outstanding tribological properties of these nanoparticles and a synergistic reinforcement effect. The combination of SWCNTs with IF-WS2 is a promising route for improving the tribological and rheological performance of thermoplastic nanocomposites. PMID:22697425

  12. Modification of Polymer Rheological Properties Through the Incorporation of Functionlized Nanoparticles

    NASA Astrophysics Data System (ADS)

    Xavier, Jean Harry; Sokolov, Jonathan; Rafailovich, Miriam; Goldstein, Lauren; Maller, Abigail

    2003-03-01

    Polymer rheology can best be controlled when addressed at the segmental level of the polymer molecule. We show that a critical dimension, Ro, exists between the radius of added nanoparticles and the polymer chain which separates a regime whereby the particles increase the internal free volume or reinforce the chain. We blended Au, Pd, and POSS nanoparticles (3-12nm) with polymers (Mw=100K-4M) and measured the glass transition and viscosity as a function of Ro. Transmission Electron Microscopy (TEM) was used to study filler size and aggregation. The effect of fillers in Tg of PS was studied using Shear Modulation Force Microscopy (SMFM). The dynamics of diffusion of fillers into the PS matrix were studied using Second Ion Mass Spectrometer (SIMS) and Neutron Reflectivity (NR) techniques will be reported. The effect of substrate interactions will be examined by comparing the results in supported and free standing films. References: 1. S.Ge, M.H. Rafailovich, J. Sokolov.Physical Review Letter, Vol. 85, 2340-2343, 9/19/2000. Support from the NSF MRSEC is gratefully acknowledged.

  13. Bone regeneration using photocrosslinked hydrogel incorporating rhBMP-2 loaded 2-N, 6-O-sulfated chitosan nanoparticles.

    PubMed

    Cao, Lingyan; Werkmeister, Jerome A; Wang, Jing; Glattauer, Veronica; McLean, Keith M; Liu, Changsheng

    2014-03-01

    Although rhBMP-2 has excellent ability to accelerate the repair of normal bone defects, limitations of its application exist in the high cost and potential side effects. This study aimed to develop a composite photopolymerisable hydrogel incorporating rhBMP-2 loaded 2-N, 6-O-sulfated chitosan nanoparticles (PH/rhBMP-2/NPs) as the bone substitute to realize segmental bone defect repair at a low growth factor dose. Firstly rhBMP-2 loaded 2-N, 6-O-sulfated chitosan nanoparticles (rhBMP-2/NPs) were prepared and characterized by DLS and TEM. Composite materials, PH/rhBMP-2/NPs were developed and investigated by SEM-EDS as well as a series of physical characterizations. Using hMSCs as an in vitro cell model, composite photopolymerisable hydrogels incorporating NPs (PH/NPs) showed good cell viability, cell adhesion and time dependent cell ingrowth. In vitro release kinetics of rhBMP-2 showed a significantly lower initial burst release from the composite system compared with the growth factor-loaded particles alone or encapsulated directly within the hydrogel, followed by a slow release over time. The bioactivity of released rhBMP-2 was validated by alkaline phosphatase (ALP) activity as well as a mineralization assay. In in vivo studies, the PH/rhBMP-2/NPs induced ectopic bone formation in the mouse thigh. In addition, we further investigated the in vivo effects of rhBMP-2-loaded scaffolds in a rabbit radius critical defect by three dimensional micro-computed tomographic (?CT) imaging, histological analysis, and biomechanical measurements. Animals implanted with the composite hydrogel containing rhBMP-2-loaded nanoparticles underwent gradual resorption with more pronounced replacement by new bone and induced reunion of the bone marrow cavity at 12 weeks, compared with animals implanted with hydrogel encapsulated growth factors alone. These data provided strong evidence that the composite PH/rhBMP-2/NPs are a promising substitute for bone tissue engineering. PMID:24438908

  14. A comparative study of two different approaches for the incorporation of silver nanoparticles into layer-by-layer films

    PubMed Central

    2014-01-01

    In this work, a comparative study about the incorporation of silver nanoparticles (AgNPs) into thin films is presented using two alternative methods, the in situ synthesis process and the layer-by-layer embedding deposition technique. The influence of several parameters such as color of the films, thickness evolution, thermal post-treatment, or distribution of the AgNPs along the coatings has been studied. Thermal post-treatment was used to induce the formation of hydrogel-like AgNPs-loaded thin films. Cross-sectional transmission electron microscopy micrographs, atomic force microscopy images, and UV-vis spectra reveal significant differences in the size and distribution of the AgNPs into the films as well as the maximal absorbance and wavelength position of the localized surface plasmon resonance absorption bands before and after thermal post-treatment. This work contributes for a better understanding of these two approaches for the incorporation of AgNPs into thin films using wet chemistry. PMID:24982607

  15. Preparation of liposomal nanoparticles incorporating terbinafine in vitro drug release studies.

    PubMed

    Koutsoulas, Charalampos; Pippa, Natassa; Demetzos, Costas; Zabka, Marian

    2014-06-01

    Terbinafine hydrochloride (TBH) (E)-N-(6,6-dimethyl-2-hepten-4-inyl)-N-methyl-1-naphthaline-methanamine(-hydrochloride) is an effective antifungal agent already existing on the market in the form of topical formulations. The present study deals with the preparation and physicochemical characterization (size, polydispersity, zeta-potential) of 1,2-Diacyl-sn-glycero-3-phosphocholine (EggPC) incorporating TBH in two different dispersion media (tris-buffered saline (TBS) of pH 7.4 or in phosphate buffer solution (PS) of pH 5.5) in order to investigate how pH of dispersion media affects the incorporation efficiency of TBH into liposomes. There were further prepared three Carbopol 934 hydrogels of different concentrations (0.5, 1 and 2%) and their viscosity was measured and evaluated. Moreover, the in vitro drug release from three liposomal gels was studied, in order to investigate the ability of liposomes to act as carriers for TBH in a gel. All formulations were found to retain their original physicochemical properties at least for three weeks. These early studies on the release kinetics from liposomal gel show that Korsmeyer-Peppas model could be the best fitted model concerning the TBH release profile and could be supported biophysically from extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. PMID:24738424

  16. Detection of gliadin in foods using a quartz crystal microbalance biosensor that incorporates gold nanoparticles.

    PubMed

    Chu, Pei-Tzu; Lin, Chih-Sheng; Chen, Wei-Jung; Chen, Chih-Feng; Wen, Hsiao-Wei

    2012-07-01

    This work develops a label-free gliadin immunosensor that is based on changes in the frequency of a quartz crystal microbalance (QCM) chip. A higher sensitivity was obtained by applying 25 nm gold nanoparticles (AuNPs) to the surface of a bare QCM electrode. Subsequently, chicken anti-gliadin antibodies (IgY) were immobilized directly on the AuNP-modified surface by cross-linking amine groups in IgY with glutaraldehyde. Experimental results revealed that the change in frequency exhibited when 2 ppm gliadin was bound to the AuNP-modified electrode was 35 Hz (48%) greater than that of the bare gold electrode. The linear dynamic range in 60% ethanol was from 1 × 10(1) to 2 × 10(5) ppb gliadin, and the calculated limit of detection (LOD) was 8 ppb. The entire detection process was completed in 40 min and was highly repeatable. Additionally, the AuNP-modified QCM system generated results in the detection of gliadin in 10 commercial food products that were consistent with those obtained using an AOAC-approved gliadin kit. In conclusion, the QCM platform provides a potential alternative means of ensuring that people with wheat allergies and celiac patients have access to gliadin-free food. PMID:22694361

  17. Luminescence enhancement in nanocomposite consisting of polyvinyl alcohol incorporated gold nanoparticles and Nile blue 690 perchlorate.

    PubMed

    Chubinidze, Ketevan; Partsvania, Besarion; Sulaberidze, Tamaz; Khuskivadze, Aleksandre; Davitashvili, Elene; Koshoridze, Nana

    2014-11-01

    We have experimentally demonstrated that the emission of visible light from the polymer matrix doped with luminescent dye and gold nanoparticles (GNPs) can be enhanced with the use of surface plasmon coupling. GNPs can enhance the luminescence intensity of nearby luminescent dye because of the interactions between the dipole moments of the dye and the surface plasmon field of the GNPs. The electric charge on the GNPs and the distance between GNPs and luminescent dye molecules have a significant effect on the luminescence intensity, and this enhancement depends strongly upon the excitation wavelength of the pumping laser source. In particular, by matching the plasmon frequency of GNPs to the frequency of the laser light source we have observed a strong luminescence enhancement of the nanocomposite consisting of GNPs coupled with luminescent dye Nile blue 690 perchlorate. This ability of controlling luminescence can be beneficially used in developing contrast agents for highly sensitive and specific optical sensing and imaging. This opens new possibilities for plasmonic applications in the solar energy field. PMID:25402873

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

    PubMed

    Díez-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

  19. Kaempferol glycosides and cardenolide glycosides, cytotoxic constituents from the seeds of Draba nemorosa (Brassicaceae)

    Microsoft Academic Search

    Surk-Sik Moon; Aziz Abdur Rahman; Maniruzzaman Manir; V. S. Jamal Ahamed

    2010-01-01

    Bioassay-directed fractionation of a methanolic extract from the seeds of Draba nemorosa (Brassicaceae) led to isolation of a new flavonol glycoside, drabanemoroside (5, kaempferol 3-O-?-L-rhamnopyranosyl-(1?2)-?-L-arabinopyranose) along with four known flavonoid derivatives (1–4), four cardenolide glycosides (6–9). Kaempferol glycosides 2 and 5 showed strong cytotoxicity against human small lung cancer cell line A549 and melanoma SK-Mel-2 with an IC50 of 0.5

  20. Kaempferol inhibits VEGF expression and in vitro angiogenesis through a novel ERK-NF?B-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 NF?B and cMyc expression, but promoted p21 expression. Examination of relationship between these genes suggested a novel ERK-NF?B-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

  1. The flavonoid kaempferol sensitizes human glioma cells to TRAIL-mediated apoptosis by proteasomal degradation of survivin

    Microsoft Academic Search

    Markus D. Siegelin; David E. Reuss; Antje Habel; Christel Herold-Mende; Andreas von Deimling

    2008-01-01

    Resistance to tumor necrosis factor - related apoptosis- inducing ligand (TRAIL\\/Apo2L) limits its potential as a drug for cancer therapy. Here, we report that kaempferol, a bioactive plant flavonoid, sensitizes U251 and U87 glioma cells to TRAIL-mediated apoptosis. In contrast, U373 cells are not affected by kaempferol treatment. Treatment of kaempferol alone for 24 h did not induce apoptosis in

  2. 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.

  3. 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 ?M, 750 ?M, 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 ?M. Above 750 ?M, 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.

  4. Antioxidant activities of curcumin and ascorbyl dipalmitate nanoparticles and their activities after incorporation into cellulose-based packaging films.

    PubMed

    Sonkaew, Piyapong; Sane, Amporn; Suppakul, Panuwat

    2012-05-30

    Curcumin (Ccm) and ascorbyl dipalmitate (ADP) nanoparticles (NPs) with average sizes of ?50 and ?80 nm, respectively, were successfully produced by rapid expansion of subcritical solutions into liquid solvents (RESOLV). Pluronic F127 was employed as a stabilizer for both Ccm- and ADP-NPs in an aqueous receiving solution. Antioxidant activities of the Ccm-NPs and ADP-NPs were subsequently investigated using four assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ABTS radical cation decolorization, ?-carotene bleaching, and ferric reducing antioxidant power. Ccm-NPs and ADP-NPs showed higher antioxidant activities than those of Ccm and ADP. Ccm-NPs yielded higher antioxidant activities than those of Ccm in ethanol and water (Ccm-EtOH and Ccm-H(2)O), respectively. ADP-NPs yielded lower antioxidant activities than that of ADP in ethanol (ADP-EtOH) but higher activities than that of ADP in water (ADP-H(2)O). Moreover, incorporation of Ccm-NPs and ADP-NPs into cellulose-based films indicated that Ccm-NPs and ADP-NPs significantly enhanced the antioxidant activities of Ccm and ADP (p < 0.05). Our results show that the environmentally benign supercritical CO(2) technique should be generally applicable to NP fabrication of other important bioactive ingredients, especially in liquid form. In addition, we suggest that Ccm-NPs and ADP-NPs can be used to reduce the dosage of Ccm and ADP and improve their bioavailability, and thus merit further investigation for antioxidant packaging film and coating applications. PMID:22583595

  5. Electrospun magnetic poly(L-lactide) (PLLA) nanofibers by incorporating PLLA-stabilized Fe3O4 nanoparticles.

    PubMed

    Shan, Dingying; Shi, Yuzhou; Duan, Shun; Wei, Yan; Cai, Qing; Yang, Xiaoping

    2013-08-01

    Magnetic poly(L-lactide) (PLLA)/Fe3O4 composite nanofibers were prepared with the purpose to develop a substrate for bone regeneration. To increase the dispersibility of Fe3O4 nanoparticles (NPs) in the PLLA matrix, a modified chemical co-precipitation method was applied to synthesize Fe3O4 NPs in the presence of PLLA. Trifluoroethanol (TFE) was used as the co-solvent for all the reagents, including Fe(II) and Fe(III) salts, sodium hydroxide, and PLLA. The co-precipitated Fe3O4 NPs were surface-coated with PLLA and demonstrated good dispersibility in a PLLA/TFE solution. The composite nanofiber electrospun from the solution displayed a homogeneous distribution of Fe3O4 NPs along the fibers using various contents of Fe3O4 NPs. X-ray diffractometer (XRD) and vibration sample magnetization (VSM) analysis confirmed that the co-precipitation process had minor adverse effects on the crystal structure and saturation magnetization (Ms) of Fe3O4 NPs. The resulting PLLA/Fe3O4 composite nanofibers showed paramagnetic properties with Ms directly related to the Fe3O4 NP concentration. The cytotoxicity of the magnetic composite nanofibers was determined using in vitro culture of osteoblasts (MC3T3-E1) in extracts and co-culture on nanofibrous matrixes. The PLLA/Fe3O4 composite nanofibers did not show significant cytotoxicity in comparison with pure PLLA nanofibers. On the contrary, they demonstrated enhanced effects on cell attachment and proliferation with Fe3O4 NP incorporation. The results suggested that this modified chemical co-precipitation method might be a universal way to produce magnetic biodegradable polyester substrates containing well-dispersed Fe3O4 NPs. This new strategy opens an opportunity to fabricate various kinds of magnetic polymeric substrates for bone tissue regeneration. PMID:23706239

  6. Production of kaempferol 3-O-rhamnoside from glucose using engineered Escherichia coli.

    PubMed

    Yang, So-Mi; Han, So Hyun; Kim, Bong-Gyu; Ahn, Joong-Hoon

    2014-08-01

    Flavonoids are ubiquitous phenolic compounds and at least 9,000 have been isolated from plants. Most flavonoids have been isolated and assessed in terms of their biological activities. Microorganisms such as Escherichia coli and Saccharomyces cerevisiae are efficient systems for the synthesis of flavonoids. Kaempferol 3-O-rhamnoside has notable biological activities such as the inhibition of the proliferation of breast cancer cells, the absorption of glucose in the intestines, and the inhibition of the self-assembly of beta amyloids. We attempted to synthesize kaempferol 3-O-rhamnoside from glucose in E. coli. Five flavonoid biosynthetic genes [tyrosine ammonia lyase (TAL), 4-coumaroyl CoA ligase (4CL), chalcone synthase (CHS), flavonol synthase (FLS), and flavonol 3-O-rhamnosyltransferase (UGT78D1)] from tyrosine were introduced into E. coli that was engineered to increase tyrosine production. By using this approach, the production of kaempferol 3-O-rhamnoside increased to 57 mg/L. PMID:24879482

  7. Increased efficiency in multijunction solar cells through the incorporation of semimetallic ErAs nanoparticles into the tunnel junction

    Microsoft Academic Search

    J. M. O. Zide; A. Kleiman-Shwarsctein; N. C. Strandwitz; J. D. Zimmerman; T. Steenblock-Smith; A. C. Gossard; A. Forman; A. Ivanovskaya; G. D. Stucky

    2006-01-01

    We report the molecular beam epitaxy growth of Al0.3Ga0.7As\\/GaAs multijunction solar cells with epitaxial, semimetallic ErAs nanoparticles at the interface of the tunnel junction. The states provided by these nanoparticles reduce the bias required to pass current through the tunnel junction by three orders of magnitude, and therefore drastically reduce the voltage losses in the tunnel junction. We have measured

  8. Increased efficiency in multijunction solar cells through the incorporation of semimetallic ErAs nanoparticles into the tunnel junction

    Microsoft Academic Search

    J. M. O. Zide; A. Kleiman-Shwarsctein; N. C. Strandwitz; J. D. Zimmerman; T. Steenblock-Smith; A. C. Gossard; A. Forman; A. Ivanovskaya; G. D. Stucky

    2007-01-01

    We report the molecular beam epitaxy growth of Al0.3Ga0.7As\\/GaAs multijunction solar cells with epitaxial, semimetallic ErAs nanoparticles at the interface of the tunnel junction. The states provided by these nanoparticles reduce the bias required to pass current through the tunnel junction by three orders of magnitude, and therefore drastically reduce the voltage losses in the tunnel junction. We have measured

  9. The effects of curing medium on flexural strength and water permeability of concrete incorporating TiO 2 nanoparticles

    Microsoft Academic Search

    Ali Nazari

    2011-01-01

    The effect of limewater on flexural strength and water permeability of TiO2 nanoparticles binary blended concrete has been investigated. TiO2 nanoparticles with partial replacement of cement by 0.5, 1.0, 1.5 and 2.0 weight percent have been used as reinforcement.\\u000a Curing of the specimens has been carried out in water and saturated limewater for 7, 28 and 90 days after casting. The

  10. Antidepressant-like Effect of Kaempferol and Quercitirin, Isolated from Opuntia ficus-indica var. saboten

    PubMed Central

    Park, Soo-Hyun; Sim, Yun-Beom; Han, Pyung-Lim; Lee, Jin-Koo

    2010-01-01

    Opuntia ficus-indica var. saboten. is widely cultivated in Jeju Island (South Korea) for use in manufacture of health foods. This study described antidepressant effect of two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. The expression of the hypothalamic POMC mRNA or plasma ?-endorphin levels were increased by extract of Opuntia ficus-indica var. saboten or its flavoniods administered orally. In addition, antidepressant activity was studied using tail suspension test (TST), forced swimming test (FST) and rota-rod test in chronically restraint immobilization stress group in mice. After restraint stress (2 hrs/day for 14 days), animals were kept in cage for 14 days without any further stress, bet with drugs. Mice were fed with a diet supplemented for 14 days and during the behavioral test period with kaempferol or quercitrin (30 mg/kg/day). POMC mRNA or plasma ?-endorphin level was increased by extract of Opuntia ficus-indica var. saboten and its flavoniods. In addition, immobility time in TST and FST was significantly reduced by kaempferol or quercitrin. In rota-rod test, the time of permanence was maintained to the semblance of control group in turning at 15 rpm. Our results suggest that two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. show a potent antidepressant effect. PMID:22110339

  11. Increased efficiency in multijunction solar cells through the incorporation of semimetallic ErAs nanoparticles into the tunnel junction

    SciTech Connect

    Zide, J.M.O.; Kleiman-Shwarsctein, A.; Strandwitz, N.C.; Zimmerman, J.D.; Steenblock-Smith, T.; Gossard, A.C.; Forman, A.; Ivanovskaya, A.; Stucky, G.D. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Chemistry Department, University of California, Santa Barbara, California 93106 (United States)

    2006-04-17

    We report the molecular beam epitaxy growth of Al{sub 0.3}Ga{sub 0.7}As/GaAs multijunction solar cells with epitaxial, semimetallic ErAs nanoparticles at the interface of the tunnel junction. The states provided by these nanoparticles reduce the bias required to pass current through the tunnel junction by three orders of magnitude, and therefore drastically reduce the voltage losses in the tunnel junction. We have measured open-circuit voltages which are 97% of the sum of the constituent cells, which result in nearly double the efficiency of our multijunction cell with a conventional tunnel junction.

  12. 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 0.8873–0.9138 and 0.9596–0.9941, 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.

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

    PubMed

    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 (R (2) values of 0.8873-0.9138 and 0.9596-0.9941, 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

  14. Improving the Power Conversion Efficiency of Ultrathin Organic Solar Cells by Incorporating Plasmonic Effects of Spheroidal Metallic Nanoparticles

    E-print Network

    Park, Namkyoo

    Improving the Power Conversion Efficiency of Ultrathin Organic Solar Cells by Incorporating be exploited to achieve efficient harvesting of solar energy. Notably, the incorporation of plasmonic effects can allow the light harvesting capability of a solar cell to be maintained even as the thickness

  15. 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

  16. The incorporation of poly(lactic- co-glycolic) acid nanoparticles into porcine small intestinal submucosa biomaterials

    Microsoft Academic Search

    Fadee G. Mondalek; Benjamin J. Lawrence; Bradley P. Kropp; Brian P. Grady; Kar-Ming Fung; Sundar V. Madihally; Hsueh-Kung Lin

    2008-01-01

    Small intestinal submucosa (SIS) derived from porcine small intestine has been intensively studied for its capacity in repairing and regenerating wounded and dysfunctional tissues. However, SIS suffers from a large spectrum of heterogeneity in microarchitecture leading to inconsistent results. In this study, we introduced nanoparticles (NPs) to SIS with an intention of decreasing the heterogeneity and improving the consistency of

  17. Hepatocyte growth factor incorporated chitosan nanoparticles augment the differentiation of stem cell into hepatocytes for the recovery of liver cirrhosis in mice

    PubMed Central

    2011-01-01

    Background Short half-life and low levels of growth factors in the niche of injured microenvironment necessitates the exogenous and sustainable delivery of growth factors along with stem cells to augment the regeneration of injured tissues. Methods Here, recombinant human hepatocyte growth factor (HGF) was incorporated into chitosan nanoparticles (CNP) by ionic gelation method and studied for its morphological and physiological characteristics. Cirrhotic mice received either hematopoietic stem cells (HSC) or mesenchymal stemcells (MSC) with or without HGF incorporated chitosan nanoparticles (HGF-CNP) and saline as control. Biochemical, histological, immunostaining and gene expression assays were carried out using serum and liver tissue samples. One way analysis of variance was used for statics application Results Serum levels of selected liver protein and enzymes were significantly increased in the combination of MSC and HGF-CNP (MSC+HGF-CNP) treated group. Immunopositive staining for albumin (Alb) and cytokeratin 18 (CK18), and reverse transcription-polymerase chain reaction (RT-PCR) for Alb, alpha fetoprotein (AFP), CK18, cytokeratin 19 (CK19) ascertained that MSC-HGF-CNP treatment could be an effective combination to repopulate liver parenchymal cells in the liver cirrhosis. Zymogram and western blotting for matrix metalloproteinases 2 and 9 (MMP2 and MMP9) revealed that MMP2 actively involved in the fibrolysis of cirrhotic tissue. Immunostaining for alpha smooth muscle actin (?SMA) and type I collagen showed decreased expression in the MSC+HGF-CNP treatment. These results indicated that HGF-CNP enhanced the differentiation of stem cells into hepatocytes and supported the reversal of fibrolysis of extracellular matrix (ECM). Conclusion Bone marrow stem cells were isolated, characterized and transplanted in mice model. Biodegradable biopolymeric nanoparticles were prepared with the pleotrophic protein molecule and it worked well for the differentiation of stem cells, especially mesenchymal phenotypic cells. Transplantation of bone marrow MSC in combination with HGF-CNP could be an ideal approach for the treatment of liver cirrhosis. PMID:21526984

  18. Biomimetic modification of synthetic hydrogels by incorporation of adhesive peptides and calcium phosphate nanoparticles: in vitro evaluation of cell behavior.

    PubMed

    Bongio, M; van den Beucken, J J J P; Nejadnik, M R; Leeuwenburgh, S C G; Kinard, L A; Kasper, F K; Mikos, A G; Jansen, J A

    2011-01-01

    The ultimate goal of this work was to develop a biocompatible and biomimetic in situ crosslinkable hydrogel scaffold with an instructive capacity for bone regenerative treatment. To this end, synthetic hydrogels were functionalized with two key components of the extracellular matrix of native bone tissue, i.e. the three-amino acid peptide sequence RGD (which is the principal integrin-binding domain responsible for cell adhesion and survival of anchorage-dependent cells) and calcium phosphate (CaP) nanoparticles in the form of hydroxyapatite (which are similar to the inorganic phase of bone tissue). Rat bone marrow osteoblast-like cells (OBLCs) were encapsulated in four different biomaterials (plain oligo(poly(ethylene glycol) fumarate) (OPF), RGD-modified OPF, OPF enriched with CaP nanoparticles and RGD-modified OPF enriched with CaP nanoparticles) and cell survival, cell spreading, proliferation and mineralized matrix formation were determined via cell viability assay, histology and biochemical analysis for alkaline phosphatase activity and calcium. This study showed that RGD peptide sequences promoted cell spreading in OPF hydrogels and hence play a crucial role in cell survival during the early stage of culture, whereas CaP nanoparticles significantly enhanced cell-mediated hydrogel mineralization. Although cell spreading and proliferation activity were inhibited, the combined effect of RGD peptide sequences and CaP nanoparticles within OPF hydrogel systems elicited a better biological response than that of the individual components. Specifically, both a sustained cell viability and mineralized matrix production mediated by encapsulated OBLCs were observed within these novel biomimetic composite systems. PMID:22179935

  19. Nanoparticles

    NASA Astrophysics Data System (ADS)

    Vaez-Zadeh, Mehdi; Mohammadi, Ali

    2014-07-01

    MnFe2O4 nanoparticles of various particle sizes were prepared by co-precipitation, in which different hydroxide concentrations were employed to control particle growth. X-ray diffraction and scanning electron microscopy were used to investigate the nanoparticle structure and morphology (shape and size). The particle size increased with increasing hydroxide concentration. The magnetization and coercivity field were measured by vibrating sample magnetometry. Changes in magnetic behavior were observed in the magnetic hysteresis loop curves of nanoparticles with increasing hydroxide concentration. In the absence of hydroxide, nanoparticles exhibited paramagnetic behavior. Increasing the hydroxide concentration caused a gradual conversion to ferrimagnetic behavior. An increased Néel temperature was observed with increasing hydroxide concentration, and the saturation magnetization exhibited a sharp decrease. Nonuniform hysteresis was observed in the magnetization curve for the sample prepared from hydroxide and ammonium.

  20. In vivo efficacy studies of layer-by-layer nano-matrix bearing kaempferol for the conditions of osteoporosis: a study in ovariectomized rat model.

    PubMed

    Kumar, Avinash; Gupta, Girish K; Khedgikar, Vikram; Gautam, Jyoti; Kushwaha, Priyanka; Changkija, Bendangla; Nagar, Geet K; Gupta, Varsha; Verma, Ashwni; Dwivedi, Anil Kumar; Chattopadhyay, Naibedya; Mishra, Prabhat Ranjan; Trivedi, Ritu

    2012-11-01

    A prototype formulation based on layer-by-layer (LbL) nano-matrix was developed to increase bioavailability of kaempferol with improved retention in bone marrow to achieve enhanced bone formation. The layer-by-layer nano-matrix was prepared by sequential adsorption of biocompatible polyelectrolytes over the preformed kaempferol-loaded CaCO(3) template. The system was pharmaceutically characterized and evaluated for osteogenic activity in ovariectomized (OVx) rats. Data have been compared to the standard osteogenic agent parathyroid hormone (PTH). Single oral dose of kaempferol loaded LbL nano-matrix formulation increased bioavailability significantly compared to unformulated kaempferol. Three months of Formulated kaempferol administration to osteopenic rats increased plasma and bone marrow Kaempferol levels by 2.8- and 1.75-fold, respectively, compared to free Kaempferol. Formulated Kaempferol increased bone marrow osteoprogenitor cells, osteogenic genes in femur, bone formation rate, and improved trabecular micro-architecture. Withdrawal of Formulated kaempferol-in OVx rats resulted in the maintenance of bone micro-architecture up to 30days, whereas micro-architectural deterioration was readily observed in OVx rats treated with unformulated kaempferol-within 15days of withdrawal. The developed novel formulation has enhanced anabolic effect in osteopenic rats through increased stimulatory effect in osteoblasts. Treatment post-withdrawal sustenance of formulated kaempferol could become a strategy to enhance bioavailability of flavanoids. PMID:22926146

  1. Incorporation of cobalt-ferrite nanoparticles into a conducting polymer in aqueous micellar medium: strategy to get photocatalytic composites.

    PubMed

    Endr?di, Balázs; Hursán, Dorottya; Petrilla, Liliána; Bencsik, Gábor; Visy, Csaba; Chams, Amani; Maslah, Nabiha; Perruchot, Christian; Jouini, Mohamed

    2014-01-01

    In this study an easy strategy for conducting polymer based nanocomposite formation is presented through the deposition of cobalt-ferrite (CoFe(2)O(4)) containing poly(3,4-ethylenedioxythiophene) (PEDOT) thin layers. The electrochemical polymerization has been performed galvanostatically in an aqueous micellar medium in the presence of the nanoparticles and the surface active Triton X-100. The nanoparticles have been characterized by Transmission electron microscopy (TEM), the thin layers has been studied by applying Scanning electron microscopy (SEM), and X-ray diffraction (XRD), and the basic electrochemical properties have been also determined. Moreover, electrocatalytic activity of the composite was demonstrated in the electrooxidation reaction of dopamine (DA). The enhanced sensitivity - related to the cobalt-ferrite content - and the experienced photocatalyitic activity are promising for future application. PMID:25125121

  2. Enhancement of oxygen reduction by incorporation of heteropolytungstate into the electrocatalytic ink of carbon supported platinum nanoparticles

    Microsoft Academic Search

    Renata Wlodarczyk; Aneta Kolary-Zurowska; Roberto Marassi; Malgorzata Chojak; Pawel J. Kulesza

    2007-01-01

    Nafion stabilized inks of Vulcan XC-72 supported platinum (20wt.%) nanoparticles (Pt\\/XC-72) were utilized to produce electrocatalytic films on glassy carbon. The catalysts were modified (activated) with phosphododecatungstic acid H3PW12O40 (PW12). Comparison was made to bare (PW12-free) electrocatalytic films. Electroreduction of dioxygen was studied at 25°C in 0.5moldm?3 H2SO4 electrolyte using rotating disk voltammetry. For the same loading of platinum (?95?gcm?2)

  3. Kaempferol glycosides and cardenolide glycosides, cytotoxic constituents from the seeds of Draba nemorosa (Brassicaceae).

    PubMed

    Moon, Surk-Sik; Rahman, Md Aziz Abdur; Manir, Md Maniruzzaman; Jamal Ahamed, V S

    2010-08-01

    Bioassay-directed fractionation of a methanolic extract from the seeds of Draba nemorosa (Brassicaceae) led to isolation of a new flavonol glycoside, drabanemoroside (5, kaempferol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranose) along with four known flavonoid derivatives (1-4), four cardenolide glycosides (6-9). Kaempferol glycosides 2 and 5 showed strong cytotoxicity against human small lung cancer cell line A549 and melanoma SK-Mel-2 with an IC(50) of 0.5 microg/mL and 1.9 microg/mL, respectively. Cardenolide glycosides 6-9 showed potent cytotoxicity (A549) in the range of 0.01-0.032 microg/mL. Their structures were characterized based on spectroscopic data (2D NMR, HRTOFMS, IR, and UV) and comparison of literature values. The carbohydrate units were also confirmed by comparing the hydrolysate of 5 with authentic monosaccharides. PMID:20803119

  4. 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

  5. The flavonols quercetin, kaempferol, and myricetin inhibit hepatocyte growth factor-induced medulloblastoma cell migration.

    PubMed

    Labbé, David; Provençal, Mathieu; Lamy, Sylvie; Boivin, Dominique; Gingras, Denis; Béliveau, Richard

    2009-04-01

    Medulloblastoma, the most common malignant brain tumor in children, is a highly metastatic disease, with up to 30% of children having evidence of disseminated disease at presentation. Recently, the hepatocyte growth factor (HGF) and its receptor, the tyrosine kinase Met, have emerged as key components of human medulloblastoma growth and metastasis, suggesting that inhibition of this pathway may represent an attractive target for the prevention and treatment of this disease. Using immunoblotting procedures, we observed that the dietary-derived flavonols quercetin, kaempferol, and myricetin inhibited HGF/Met signaling in a medulloblastoma cell line (DAOY), preventing the formation of actin-rich membrane ruffles and resulting in the inhibition of Met-induced cell migration in Boyden chambers. Furthermore, quercetin and kaempferol also strongly diminished HGF-mediated Akt activation. Interestingly, the inhibitory effects of quercetin on the tyrosine kinase receptor Met [half-maximal inhibitory effect (IC(50)) of 12 micromol/L] or on the Met-induced activation of Akt (IC(50) of 2.5 micromol/L) occurred at concentrations achievable through dietary approaches. These results highlight quercetin, kaempferol, and myricetin as dietary-derived inhibitors of Met activity and suggest that this inhibitory effect may contribute to the chemopreventive properties of these molecules. PMID:19244381

  6. Isolation and evaluation of kaempferol glycosides from the fern Neocheiropteris palmatopedata

    PubMed Central

    Yang, Jian-Hong; Kondratyuk, Tamara P.; Marler, Laura E.; Qiu, Xi; Choi, Yongsoo; Cao, Hongmei; Yu, Rui; Sturdy, Megan; Pegan, Scott; Liu, Ying; Wang, Li-Qin; Mesecar, Andrew D.; Van Breemen, Richard B.; Pezzuto, John M.; Fong, Harry H. S.; Chen, Ye-Gao; Zhang, Hong-Jie

    2010-01-01

    Three new kaempferol glycosides, named palmatosides A (1), B (2) and C (3), together with three known kaempferol glycosides, multiflorins A (4) and B (5), and afzelin (6), were isolated from the roots of the fern Neocheiropteris palmatopedata. Palmatosides A (1) and B (2) were determined to be novel kaempferol glycosides, each possessing an unusual sugar moiety containing a 4, 4-dimethyl-3-oxo-butoxy substituent group. The isolated compounds were evaluated for their cancer chemopreventive potential based on their ability to inhibit tumor necrosis factor alpha (TNF-?)-induced NF-?B activity, nitric oxide (NO) production, aromatase, quinone reductase 2 (QR-2) and COX-1/-2 activities. Palmatosides B (2) and C (3) inhibited TNF-?-induced NF-?B activity with IC50 values of 15.7 and 24.1 ?M, respectively; multiflorin A (4) inhibited aromatase enzyme with an IC50 value of 15.5 ?M; afzelin (6) showed 68.3% inhibition against QR2 at a concentration of 11.5 ?g/ml; palmatoside A (1) showed 52 % inhibition against COX-1 enzyme at a concentration of 10 ?g/ml; and multiflorin B (5) showed 52 % inhibition against nitric oxide production at a concentration of 20 ?g/ml. In addition, compounds 3-6 were shown to bind QR2 enzyme using LC-MS ultrafiltration binding assay. PMID:20100622

  7. 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 [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece) [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece); Institute of Biomedical Research and Technology (BIOMED), 51 Papanastasiou str., 41222 Larissa (Greece); Simos, George, E-mail: simos@med.uth.gr [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece) [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece); Institute of Biomedical Research and Technology (BIOMED), 51 Papanastasiou str., 41222 Larissa (Greece)

    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.

  8. Kaempferol modulates pro-inflammatory NF-?B activation by suppressing advanced glycation endproducts-induced NADPH oxidase

    PubMed Central

    Kim, Ji Min; Lee, Eun Kyeong; Kim, Dae Hyun; Yu, Byung Pal

    2010-01-01

    Advanced glycation endproducts (AGE) are oxidative products formed from the reaction between carbohydrates and a free amino group of proteins that are provoked by reactive species (RS). It is also known that AGE enhance the generation of RS and that the binding of AGE to a specific AGE receptor (RAGE) induces the activation of the redox-sensitive, pro-inflammatory transcription factor, nuclear factor-kappa B (NF-?B). In this current study, we investigated the anti-oxidative effects of short-term kaempferol supplementation on the age-related formation of AGE and the binding activity of RAGE in aged rat kidney. We further investigated the suppressive action of kaempferol against AGE's ability to stimulate activation of pro-inflammatory NF-?B and its molecular mechanisms. For this study, we utilized young (6 months old), old (24 months old), and kaempferol-fed (2 and 4 mg/kg/day for 10 days) old rats. In addition, for the molecular work, the rat endothelial cell line, YPEN-1 was used. The results show that AGE and RAGE were increased during aging and that these increases were blunted by kaempferol. In addition, dietary kaempferol reduced age-related increases in NF-?B activity and NF-?B-dependant pro-inflammatory gene activity. The most significant new finding from this study is that kaempferol supplementation prevented age-related NF-?B activation by suppressing AGE-induced nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase). Taken together, our results demonstrated that dietary kaempferol exerts its anti-oxidative and anti-inflammatory actions by modulating the age-related NF-?B signaling cascade and its pro-inflammatory genes by suppressing AGE-induced NADPH oxidase activation. Based on these data, dietary kaempferol is proposed as a possible anti-AGE agent that may have the potential for use in anti-inflammation therapies. PMID:20431987

  9. 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

  10. Absorption, Conjugation and Efflux of the Flavonoids, Kaempferol and Galangin, Using the Intestinal CACO-2/TC7 Cell Model

    PubMed Central

    Barrington, Robert; Williamson, Gary; Bennett, Richard N; Davis, Barry D; Brodbelt, Jennifer S; Kroon, Paul A

    2009-01-01

    Flavonoids are biologically active compounds in food with potential health effects. We have used the Caco-2 cell monolayer model to study the absorption and metabolism of two flavonols, a class of flavonoids, specifically kaempferol and galangin. Metabolism experiments allowed identification of 5 kaempferol conjugates: 3-, 7- and 4?-glucuronide, a sulphate and a glucurono-sulphate; and 4 galangin conjugates: 3-, 5- and 7-glucuronides, and a sulphate, using specific enzyme hydrolysis, HPLC-MS, and HPLC with post column metal complexation/tandem MS. Transport studies showed that the flavonols were conjugated inside the cells then transported across the monolayer or effluxed back to the apical side. Sulphated conjugates were preferentially effluxed back to the apical side, whereas glucuronides were mostly transported to the basolateral side. For kaempferol, a small amount of the unconjugated aglycone permeated in both directions, indicating some passive diffusion. When kaempferol-3-glucuronide and quercetin7-sulphate were applied to either side of the cells, no permeation in either direction was observed, indicating that conjugates cannot re-cross the cell monolayer. Formation of apical kaempferol-7- and 4?-glucuronides was readily saturated, whereas formation of other conjugates at the apical side and all at the basolateral side increased with increasing concentration of kaempferol, implying different transporters are responsible at the apical and basolateral sides. The results highlight the important but complex metabolic changes occurring in flavonoids during absorption. PMID:20046888

  11. 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

  12. Fibrin-based scaffold incorporating VEGF- and bFGF-loaded nanoparticles stimulates wound healing in diabetic mice.

    PubMed

    Losi, Paola; Briganti, Enrica; Errico, Cesare; Lisella, Antonella; Sanguinetti, Elena; Chiellini, Federica; Soldani, Giorgio

    2013-08-01

    Diabetic skin ulcers are difficult to heal spontaneously due to the reduced levels and activity of endogenous growth factors. Recombinant human vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are known to stimulate cell proliferation and accelerate wound healing. Direct delivery of VEGF and bFGF at the wound site in a sustained and controllable way without loss of bioactivity would enhance their biological effects. The aim of this study was to develop a poly(ether)urethane-polydimethylsiloxane/fibrin-based scaffold containing poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with VEGF and bFGF (scaffold/GF-loaded NPs) and to evaluate its wound healing properties in genetically diabetic mice (db/db). The scaffold application on full-thickness dorsal skin wounds significantly accelerated wound closure at day 15 compared to scaffolds without growth factors (control scaffold) or containing unloaded PLGA nanoparticles (scaffold/unloaded NPs). However, the closure rate was similar to that observed in mice treated with scaffolds containing free VEGF and bFGF (scaffold/GFs). Both scaffolds containing growth factors induced complete re-epithelialization, with enhanced granulation tissue formation/maturity and collagen deposition compared to the other groups, as revealed by histological analysis. The ability of the scaffold/GF-loaded NPs to promote wound healing in a diabetic mouse model suggests its potential use as a dressing in patients with diabetic foot ulcers. PMID:23603001

  13. Colorimetric Assay for Determination of Lead (II) Based on Its Incorporation into Gold Nanoparticles during Their Synthesis

    PubMed Central

    Ding, Nan; Cao, Qian; Zhao, Hong; Yang, Yimin; Zeng, Lixi; He, Yujian; Xiang, Kaixiang; Wang, Guangwei

    2010-01-01

    In this report, we present a new method for visual detection of Pb2+. Gold nanoparticles (Au-NPs) were synthesized in one step at room temperature, using gallic acid (GA) as reducer and stabilizer. Pb2+ is added during the gold nanoparticle formation. Analysis of Pb2+ is conducted by a dual strategy, namely, colorimetry and spectrometry. During Au-NPs synthesis, addition of Pb2+ would lead to formation of Pb-GA complex, which can induce the aggregation of newly-formed small unstable gold nanoclusters. Consequently, colorimetric detection of trace Pb2+ can be realized. As the Pb2+ concentration increases, the color turns from red-wine to purple, and finally blue. This method offers a sensitive linear correlation between the shift of the absorption band (??) and logarithm of Pb2+ concentration ranging from 5.0 × 10?8 to 1.0 × 10?6 M with a linear fit coefficient of 0.998, and a high selectivity for Pb2+ detection with a low detection limit down to 2.5 × 10?8 M. PMID:22163517

  14. 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 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

  15. 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.

  16. 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.

  17. Influence of Cd2+/S2- molar ratio and of different capping environments in the optical properties of CdS nanoparticles incorporated within a hybrid diureasil matrix

    NASA Astrophysics Data System (ADS)

    Gonçalves, Luis F. F. F.; Silva, Carlos J. R.; Kanodarwala, Fehmida K.; Stride, John A.; Pereira, Mario R.; Gomes, Maria J. M.

    2014-09-01

    The incorporation of CdS nanoparticles (NPs), as prepared through colloidal methods using reverse micelles, within diureasil hybrid organic-inorganic sol-gel matrices was investigated. Several experimental conditions, namely the influence of capping agent 3-mercaptopropyltrimethoxysilane (MPTMS) or the use of tetraethoxysilane (TEOS), were studied in order to assure the preservation of the original optical properties of colloidal CdS NPs after the incorporation of the NPs within the solid diureasil hybrid matrix. The diureasil matrix is based on a siliceous network cross linked through urea bonds to poly(oxyethylene)/poly(oxypropylene) (PEO/PPO) chains. The influence of the Cd2+/S2- molar ratio of the NPs in the stability and dispersion of the NPs within the diureasil matrix was also investigated. The obtained CdS doped hybrid matrix was characterized by absorption, steady-state and time-resolved photoluminescence (PL) spectroscopy and by transmission electron microscopy (TEM). The stability of the CdS NPs within the hybrid matrix showed to be dependent on the Cd2+/S2- molar ratio used in the synthesis of the NPs. The use of MPTMS proved to be crucial in the preservation of the original optical properties of the colloidal CdS NPs after the incorporation of the NPs within the hybrid matrix. The effect of MPTMS was in turn influenced by the Cd2+/S2- molar ratio employed in the synthesis of the CdS NPs. The use of MPTMS was less effective when Cd2+/S2- molar ratio equal to 0.5 was used. In the absence of MPTMS or TEOS larger NPs size distribution and clustering of the CdS NPs were obtained after the transfer of the NPs into the hybrid matrix.

  18. NK105, a paclitaxel-incorporating micellar nanoparticle, is a more potent radiosensitising agent compared to free paclitaxel

    PubMed Central

    Negishi, T; Koizumi, F; Uchino, H; Kuroda, J; Kawaguchi, T; Naito, S; Matsumura, Y

    2006-01-01

    NK105 is a micellar nanoparticle formulation designed to enhance the delivery of paclitaxel (PTX) to solid tumours. It has been reported to exert antitumour activity in vivo and to have reduced neurotoxicity as compared to that of free PTX. The purpose of this study was to investigate the radiosensitising effect of NK105 in comparison with that of PTX. Lewis lung carcinoma (LLC)-bearing mice were administered a single intravenous (i.v.) injection of PTX or NK105; 24?h after the drug administration, a proportion of the mice received radiation to the tumour site or lung fields. Then, the antitumour activity and lung toxicity were evaluated. In one subset of mice, the tumours were excised and specimens were prepared for analysis of the cell cycle distribution by flow cytometry. Combined NK105 treatment with radiation yielded significant superior antitumour activity as compared to combined PTX treatment with radiation (P=0.0277). On the other hand, a histopathological study of lung sections revealed no significant difference in histopathological changes between mice treated with PTX and radiation and those treated with NK105 and radiation. Flow-cytometric analysis showed that NK105-treated LLC tumour cells showed more severe arrest at the G2/M phase as compared to PTX-treated tumour cells. The superior radiosensitising activity of NK105 was thus considered to be attributable to the more severe cell cycle arrest at the G2/M phase induced by NK105 as compared to that induced by free PTX. The present study results suggest that further clinical trials are warranted to determine the efficacy and feasibility of combined NK105 therapy with radiation. PMID:16909136

  19. Mechanisms of transformation of the antioxidant kaempferol into depsides. Gamma-radiolysis study in methanol and ethanol.

    PubMed

    Marfak, A; Trouillas, P; Allais, D P; Calliste, C A; Cook-Moreau, J; Duroux, J L

    2003-09-01

    In this study, we irradiated the antioxidant kaempferol in ethanol and methanol solutions with gamma rays at doses ranging from 0.2-20 kGy. NMR and ES-MS spectroscopy were used to identify radiolysis products. Two depsides, [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) methyl acetate and [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) ethyl acetate, were the major compounds of kaempferol degradation in methanol and in ethanol, respectively. Other products formed in low concentrations were identified as [4-hydroxyphenyl](oxo) methyl acetate, [4-hydroxyphenyl](oxo) ethyl acetate, and depside [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) acetic acid. The formation of the latter was observed in both solvents. We propose degradation mechanisms that suggest that (.)CH(2)OH and CH(3)(.)CHOH, produced by solvent radiolysis, react with the 3-OH kaempferol group because of its high H-donor capacity. pi-Electron delocalization in the flavonoxy formed after the first H-transfer leads to C-ring opening and consequently to the formation of depsides. G calculation of the degradation products and of (.)CH(2)OH and CH(3)(.)CHOH radicals confirmed the proposed mechanism of kaempferol radiolysis. The rate constants for the reaction between kaempferol and these free radicals were also calculated. Formation of depside has also been observed in many studies of the oxidation of flavonoids; those studying human metabolism have suggested similar redox transformation of flavonols. The antioxidant activities of radiolysis products were evaluated and compared to those of kaempferol. PMID:12926994

  20. Inhibitory effects of kaempferol on the invasion of human breast carcinoma cells by downregulating the expression and activity of matrix metalloproteinase-9.

    PubMed

    Li, Chenglin; Zhao, Yuanwei; Yang, Dan; Yu, Yanyan; Guo, Hao; Zhao, Ziming; Zhang, Bei; Yin, Xiaoxing

    2015-02-01

    Matrix metalloproteinases (MMPs) have been regarded as major critical molecules assisting tumor cells during metastasis, for excessive ECM (ECM) degradation, and cancer cell invasion. In the present study, in vitro and in vivo assays were employed to examine the inhibitory effects of kaempferol, a natural polyphenol of flavonoid family, on tumor metastasis. Data showed that kaempferol could inhibit adhesion, migration, and invasion of MDA-MB-231 human breast carcinoma cells. Moreover, kaempferol led to the reduced activity and expression of MMP-2 and MMP-9, which were detected by gelatin zymography, real-time PCR, and western blot analysis, respectively. Further elucidation of the mechanism revealed that kaempferol treatment inhibited the activation of transcription factor activator protein-1 (AP-1) and MAPK signaling pathway. Moreover, kaempferol repressed phorbol-12-myristate-13-acetate (PMA)-induced MMP-9 expression and activity through suppressing the translocation of protein kinase C? (PKC?) and MAPK signaling pathway. Our results also indicated that kaempferol could block the lung metastasis of B16F10 murine melanoma cells as well as the expression of MMP-9 in vivo. Taken together, these results demonstrated that kaempferol could inhibit cancer cell invasion through blocking the PKC?/MAPK/AP-1 cascade and subsequent MMP-9 expression and its activity. Therefore, kaempferol might act as a therapeutic potential candidate for cancer metastasis. PMID:25453494

  1. Galangin and Kaempferol Suppress Phorbol-12-Myristate-13-Acetate-Induced Matrix Metalloproteinase-9 Expression in Human Fibrosarcoma HT-1080 Cells

    PubMed Central

    Choi, Yu Jung; Lee, Young Hun; Lee, Seung-Taek

    2015-01-01

    Matrix metalloproteinase (MMP)-9 degrades type IV collagen in the basement membrane and plays crucial roles in several pathological implications, including tumorigenesis and inflammation. In this study, we analyzed the effect of flavonols on MMP-9 expression in phorbol-12-myristate-13-acetate (PMA)-induced human fibrosarcoma HT-1080 cells. Galangin and kaempferol efficiently decreased MMP-9 secretion, whereas fisetin only weakly decreased its secretion. Galangin and kaempferol did not affect cell viability at concentrations up to 30 ?M. Luciferase reporter assays showed that galangin and kaempferol decrease transcription of MMP-9 mRNA. Moreover, galangin and kaempferol strongly reduce I?B? phosphorylation and significantly decrease JNK phosphorylation. These results indicate that galangin and kaempferol suppress PMA-induced MMP-9 expression by blocking activation of NF-?B and AP-1. Therefore, these flavonols could be used as chemopreventive agents to lower the risk of diseases involving MMP-9. PMID:25518925

  2. Quantum dots (QDs) based fluorescence probe for the sensitive determination of kaempferol.

    PubMed

    Tan, Xuanping; Liu, Shaopu; Shen, Yizhong; He, Youqiu; Yang, Jidong

    2014-12-10

    In this work, using the quenching of fluorescence of thioglycollic acid (TGA)-capped CdTe quantum dots (QDs), a novel method for the determination of kaempferol (KAE) has been developed. Under optimum conditions, a linear calibration plot of the quenched fluorescence intensity at 552nm against the concentration of KAE was observed in the range of 4-44?gmL(-1) with a detection limit (3?/K) of 0.79?gmL(-1). In addition, the detailed reaction mechanism has also been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-vis) absorption and fluorescence (FL) spectroscopy. The method has been applied for the determination of KAE in pharmaceutical preparations with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation. PMID:24929317

  3. Quantum dots (QDs) based fluorescence probe for the sensitive determination of kaempferol

    NASA Astrophysics Data System (ADS)

    Tan, Xuanping; Liu, Shaopu; Shen, Yizhong; He, Youqiu; Yang, Jidong

    2014-12-01

    In this work, using the quenching of fluorescence of thioglycollic acid (TGA)-capped CdTe quantum dots (QDs), a novel method for the determination of kaempferol (KAE) has been developed. Under optimum conditions, a linear calibration plot of the quenched fluorescence intensity at 552 nm against the concentration of KAE was observed in the range of 4-44 ?g mL-1 with a detection limit (3?/K) of 0.79 ?g mL-1. In addition, the detailed reaction mechanism has also been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-vis) absorption and fluorescence (FL) spectroscopy. The method has been applied for the determination of KAE in pharmaceutical preparations with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation.

  4. Kaempferol inhibits enterovirus 71 replication and internal ribosome entry site (IRES) activity through FUBP and HNRP proteins.

    PubMed

    Tsai, Fuu-Jen; Lin, Cheng-Wen; Lai, Chien-Chen; Lan, Yu-Ching; Lai, Chih-Ho; Hung, Chien-Hui; Hsueh, Kai-Chung; Lin, Ting-Hsu; Chang, Hebron C; Wan, Lei; Sheu, Jim Jinn-Chyuan; Lin, Ying-Ju

    2011-09-15

    Flavonoids are associated with multiple biological and pharmacological activities, including anti-enterovirus activity. An internal ribosomal entry site (IRES) required for viral protein translation is a potential drug target for enterovirus 71 (EV71). Regulation translation initiation requires the interaction of IRES specific trans-acting host factors with viral IRES element. By evaluation of 12 flavonoids against EV71 infection, we found that (a) 7,8-dihydroxyflavone, kaempferol, quercetin, hesperetin and hesperidin exhibited more than 80% of cell survival and inhibition of EV71 infection; however, no anti-oxidative effects were noted from these flavonoids; (b) among them, only 7,8-dihydroxyflavone, kaempferol and hesperetin showed 40% of viral IRES activity; (c) kaempferol interfered with EV71 virus replication and pseudotyped virus production; and (d) FUBP1, FUBP3, HNRPD, HNRH1 and HNRPF proteins are associated with EV71 5'-UTR as shown using RNA affinity pull-down assay coupled with LC-MS/MS analysis. We firstly found that kaempferol may change the composition of these IRES associated trans-acting factors, and affect IRES function and EV71 virus replication. These studies help not only to understand the IRES function but also the mechanism by which drug induced cellular proteins are acting against EV71 infection. PMID:25212137

  5. Kaempferol inhibits IL-1?-stimulated, RANKL-mediated osteoclastogenesis via downregulation of MAPKs, c-Fos, and NFATc1.

    PubMed

    Lee, Won-Seok; Lee, Eun-Gyeong; Sung, Myung-Soon; Yoo, Wan-Hee

    2014-08-01

    Kaempferol is one of the most common flavonoid that is present in a variety of vegetables and fruits and has effects on bone metabolism. The present study was performed to define the effects of kaempferol on interleukin (IL)-1?-stimulated receptor activator of NF-?B ligand (RANKL)-mediated osteoclast differentiation. Bone marrow cells were harvested from 6-week-old male imprinting control region mice, and the differentiation of osteoclasts from these cells was evaluated by tartrate-resistant acid phosphatase staining and resorption pit formation assay. Phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated p38, phosphorylated c-Jun amino-terminal kinase, NF-?B (p65), I?B?, c-Fos, and nuclear factor of activated T cells c1 (NFATc1) expressions were examined by Western blotting and quantitative RT-PCR. Kaempferol inhibits IL-1?-stimulated, RANKL-mediated osteoclast differentiation and also inhibits IL-1?-stimulated, RANKL-mediated phosphorylation of ERK 1/2, p38 and JNK MAP kinases, and expressions of c-Fos and NFATc1. These results indicate that kaempferol has an inhibitory role in the bone loss by preventing osteoclast formation and suggest that it might be a novel therapeutic agent for the treatment of inflammatory arthritis by managing bone destruction. PMID:24696323

  6. Effects of Long-Term Feeding of the Polyphenols Resveratrol and Kaempferol in Obese Mice

    PubMed Central

    Montero, Mayte; de la Fuente, Sergio; Fonteriz, Rosalba I.; Moreno, Alfredo; Alvarez, Javier

    2014-01-01

    The effect of the intake of antioxidant polyphenols such as resveratrol and others on survival and different parameters of life quality has been a matter of debate in the last years. We have studied here the effects of the polyphenols resveratrol and kaempferol added to the diet in a murine model undergoing long-term hypercaloric diet. Using 50 mice for each condition, we have monitored weight, survival, biochemical parameters such as blood glucose, insulin, cholesterol, triglycerides and aspartate aminotransferase, neuromuscular coordination measured with the rotarod test and morphological aspect of stained sections of liver and heart histological samples. Our data show that mice fed since they are 3-months-old with hypercaloric diet supplemented with any of these polyphenols reduced their weight by about 5–7% with respect to the controls fed only with hypercaloric diet. We also observed that mice fed with any of the polyphenols had reduced levels of glucose, insulin and cholesterol, and better marks in the rotarod test, but only after 1 year of treatment, that is, during senescence. No effect was observed in the rest of the parameters studied. Furthermore, although treatment with hypercaloric diets induced large changes in the pattern of gene expression in liver, we found no significant changes in gene expression induced by the presence of any of the polyphenols. Thus, our data indicate that addition of resveratrol or kaempferol to mice food produces an initial decrease in weight in mice subjected to hypercaloric diet, but beneficial effects in other parameters such as blood glucose, insulin and cholesterol, and neuromuscular coordination, only appear after prolonged treatments. PMID:25386805

  7. nanoparticles

    NASA Astrophysics Data System (ADS)

    Olive-Méndez, Sion F.; Santillán-Rodríguez, Carlos R.; González-Valenzuela, Ricardo A.; Espinosa-Magaña, Francisco; Matutes-Aquino, José A.

    2014-04-01

    In this work, we present the role of vanadium ions (V+5 and V+3), oxygen vacancies (VO), and interstitial zinc (Zni) to the contribution of specific magnetization for a mixture of ZnO-V2O5 nanoparticles (NPs). Samples were obtained by mechanical milling of dry powders and ethanol-assisted milling for 1 h with a fixed atomic ratio V/Zn?=?5% at. For comparison, pure ZnO samples were also prepared. All samples exhibit a room temperature magnetization ranging from 1.18?×?10-3 to 3.5?×?10-3 emu/gr. Pure ZnO powders (1.34?×?10-3 emu/gr) milled with ethanol exhibit slight increase in magnetization attributed to formation of Zni, while dry milled ZnO powders exhibit a decrease of magnetization due to a reduction of VO concentration. For the ZnO-V2O5 system, dry milled and thermally treated samples under reducing atmosphere exhibit a large paramagnetic component associated to the formation of V2O3 and secondary phases containing V+3 ions; at the same time, an increase of VO is observed with an abrupt fall of magnetization to ??~?0.7?×?10-3 emu/gr due to segregation of V oxides and formation of secondary phases. As mechanical milling is an aggressive synthesis method, high disorder is induced at the surface of the ZnO NPs, including VO and Zni depending on the chemical environment. Thermal treatment restores partially structural order at the surface of the NPs, thus reducing the amount of Zni at the same time that V2O5 NPs segregate reducing the direct contact with the surface of ZnO NPs. Additional samples were milled for longer time up to 24 h to study the effect of milling on the magnetization; 1-h milled samples have the highest magnetizations. Structural characterization was carried out using X-ray diffraction and transmission electron microscopy. Identification of VO and Zni was carried out with Raman spectra, and energy-dispersive X-ray spectroscopy was used to verify that V did not diffuse into ZnO NPs as well to quantify O/Zn ratios.

  8. Kaempferol Reduces Matrix Metalloproteinase-2 Expression by Down-Regulating ERK1/2 and the Activator Protein-1 Signaling Pathways in Oral Cancer Cells

    PubMed Central

    Lin, Chiao-Wen; Chen, Pei-Ni; Chen, Mu-Kuan; Yang, Wei-En; Tang, Chih-Hsin; Yang, Shun-Fa; Hsieh, Yih-Shou

    2013-01-01

    Background Kaempferol has been proposed as a potential drug for cancer chemoprevention and treatment because it is a natural polyphenol contained in plant-based foods. Recent studies have demonstrated that kaempferol protects against cardiovascular disease and cancer. Based on this finding, we investigated the mechanisms by which kaempferol produces the anti-metastatic effect in human tongue squamous cell carcinoma SCC4 cells. Methodology/Principal Findings In this study, we provided molecular evidence associated with the anti-metastatic effect of kaempferol by demonstrating a substantial suppression of SCC4 cell migration and invasion. This effect was associated with reduced expressions of MMP-2 and TIMP-2 mRNA and protein levels. Analysis of the transcriptional regulation indicated that kaempferol inhibited MMP-2 transcription by suppressing c-Jun activity. Kaempferol also produced an inhibitory effect on the phosphorylation of ERK1/2. Conclusions These findings provide new insights into the molecular mechanisms involved in the anti-metastatic effect of kaempferol, and are valuable in the prevention of oral cancer metastasis. PMID:24278338

  9. Curcumin and kaempferol prevent lysozyme fibril formation by modulating aggregation kinetic parameters.

    PubMed

    Borana, Mohanish S; Mishra, Pushpa; Pissurlenkar, Raghuvir R S; Hosur, Ramakrishna V; Ahmad, Basir

    2014-03-01

    Interaction of small molecule inhibitors with protein aggregates has been studied extensively, but how these inhibitors modulate aggregation kinetic parameters is little understood. In this work, we investigated the ability of two potential aggregation inhibiting drugs, curcumin and kaempferol, to control the kinetic parameters of aggregation reaction. Using thioflavin T fluorescence and static light scattering, the kinetic parameters such as amplitude, elongation rate constant and lag time of guanidine hydrochloride-induced aggregation reactions of hen egg white lysozyme were studied. We observed a contrasting effect of inhibitors on the kinetic parameters when aggregation reactions were measured by these two probes. The interactions of these inhibitors with hen egg white lysozyme were investigated using fluorescence quench titration method and molecular dynamics simulations coupled with binding free energy calculations. We conclude that both the inhibitors prolong nucleation of amyloid aggregation through binding to region of the protein which is known to form the core of the protein fibril, but once the nucleus is formed the rate of elongation is not affected by the inhibitors. This work would provide insight into the mechanism of aggregation inhibition by these potential drug molecules. PMID:24468532

  10. Engineered native pathways for high kaempferol and caffeoylquinate production in potato.

    PubMed

    Rommens, Caius M; Richael, Craig M; Yan, Hua; Navarre, Duroy A; Ye, Jingsong; Krucker, Michele; Swords, Kathy

    2008-12-01

    Flavonols and caffeoylquinates represent important groups of phenolic antioxidants with health-promoting activities. The genetic potential of potato (Solanum tuberosum) to produce high levels of these dietary compounds has not been realized in currently available commodity varieties. In this article, it is demonstrated that tuber-specific expression of the native and slightly modified MYB transcription factor gene StMtf1(M) activates the phenylpropanoid biosynthetic pathway. Compared with untransformed controls, transgenic tubers contained fourfold increased levels of caffeoylquinates, including chlorogenic acid (CGA) (1.80 mg/g dry weight), whilst also accumulating various flavonols and anthocyanins. Subsequent impairment of anthocyanin biosynthesis through silencing of the flavonoid-3',5'-hydroxylase (F3'5'h) gene resulted in the accumulation of kaempferol-rut (KAR) to levels that were approximately 100-fold higher than in controls (0.12 mg/g dry weight). The biochemical changes were associated with increased expression of both the CGA biosynthetic hydroxycinnamoyl-CoA quinate hydroxycinnamoyl transferase (Hqt) gene and the upstream chorismate mutase (Cm) and prephenate dehydratase (Pdh) genes. Field trials indicated that transgenic lines produced similar tuber yields to the original potato variety Bintje. Processed products of these lines retained most of their phenylpropanoids and were indistinguishable from untransformed controls in texture and taste. PMID:18662373

  11. Self-assembly of a model peptide incorporating a hexa-histidine sequence attached to an oligo-alanine sequence, and binding to gold NTA/nickel nanoparticles.

    PubMed

    Hamley, Ian W; Kirkham, Steven; Dehsorkhi, Ashkan; Castelletto, Valeria; Adamcik, Jozef; Mezzenga, Raffaele; Ruokolainen, Janne; Mazzuca, Claudia; Gatto, Emanuela; Venanzi, Mariano; Placidi, Ernesto; Bilalis, Panayiotis; Iatrou, Hermis

    2014-09-01

    Amyloid fibrils are formed by a model surfactant-like peptide (Ala)10-(His)6 containing a hexa-histidine tag. This peptide undergoes a remarkable two-step self-assembly process with two distinct critical aggregation concentrations (cac's), probed by fluorescence techniques. A micromolar range cac is ascribed to the formation of prefibrillar structures, whereas a millimolar range cac is associated with the formation of well-defined but more compact fibrils. We examine the labeling of these model tagged amyloid fibrils using Ni-NTA functionalized gold nanoparticles (Nanogold). Successful labeling is demonstrated via electron microscopy imaging. The specificity of tagging does not disrupt the ?-sheet structure of the peptide fibrils. Binding of fibrils and Nanogold is found to influence the circular dichroism associated with the gold nanoparticle plasmon absorption band. These results highlight a new approach to the fabrication of functionalized amyloid fibrils and the creation of peptide/nanoparticle hybrid materials. PMID:25105839

  12. Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics

    PubMed Central

    Hu, Yongfeng; Liu, Liguo; Yang, Fan; Jin, Qi

    2012-01-01

    Background New therapeutic tools and molecular targets are needed for treatment of Japanese encephalitis virus (JEV) infections. JEV requires an ?-1 translational frameshift to synthesize the NS1' protein required for viral neuroinvasiveness. Several flavonoids have been shown to possess antiviral activity in vitro against a wide spectrum of viruses. To date, the antiviral activities of flavonol kaempferol (Kae) and isoflavonoid daidzin (Dai) against JEV have not been described. Methodology/Principal Findings The 50% cytotoxic concentration (CC50) and 50% effective concentration (EC50) against JEV were investigated in BHK21 cells by MTS reduction. Activity against viral genomic RNA and proteins was measured by real-time RT-PCR and western blotting. The frameshift site RNA-binding characterization was also determined by electrospray ionization mass spectrometry, isothermal titration calorimetry and autodocking analysis. EC50 values of Kae and Dai were 12.6 and 25.9 µM against JEV in cells pretreated before infection, whereas in cells infected before treatment, EC50 was 21.5 and 40.4 µM, respectively. Kae exhibited more potent activity against JEV and RNA binding in cells following internalization through direct inhibition of viral replication and protein expression, indicating that its antiviral activity was principally due to direct virucidal effects. The JEV frameshift site RNA (fsRNA) was selected as a target for assaying Kae and Dai. ITC of fsRNA revealed an apparent Kb value for Kae that was nine fold stronger than that for Dai. This binding was confirmed and localized to the RNA using ESI-MS and autodock analysis. Kae could form non-covalent complexes with fsRNA more easily than Dai could. Conclusions/Significance Kae demonstrates more potent antiviral activity against JEV than does Dai. The mode of action of Kae as an anti-JEV agent seems to be related to its ability to inactivate virus by binding with JEV fsRNA. PMID:22276167

  13. Amplified electrochemical detection of DNA through the aggregation of Au nanoparticles on electrodes and the incorporation of methylene blue into the DNA-crosslinked structure.

    PubMed

    Li, Di; Yan, Yiming; Wieckowska, Agnieszka; Willner, Itamar

    2007-09-14

    The amplified electrochemical sensing of DNA is accomplished by the analyte-induced aggregation of nucleic acid-functionalized Au nanoparticles, deposition of the aggregates on a thiolated monolayer-functionalized electrode, and the voltammetric analysis of the redox-active methylene blue intercalated in the nucleic acid duplexes associated with the aggregates. PMID:18080539

  14. Optical fiber dissolved oxygen sensor based on Pt(II) complex and core-shell silica nanoparticles incorporated with sol–gel matrix

    Microsoft Academic Search

    Cheng-Shane Chu; Yu-Lung Lo

    2010-01-01

    This paper presents a highly sensitive dissolved oxygen sensor comprising an optical fiber coated at one end with core-shell silica nanoparticles and platinum(II) meso-tetrakis (pentafluorophenyl) porphyrin (PtTFPP) embedded in an n-octyltriethoxysilane (Octyl-triEOS)\\/tetraethylorthosilane (TEOS) composite xerogel. The sensitivity of optical fiber dissolved oxygen sensor is quantified in terms of the ratio I0\\/I100, where I0 and I100 represent the detected fluorescence intensities

  15. 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.

  16. In vitro release and in vitro–in vivo correlation for silybin meglumine incorporated into hollow-type mesoporous silica nanoparticles

    PubMed Central

    Cao, Xia; Deng, Wen-Wen; Fu, Min; Wang, Liang; Tong, Shan-Shan; Wei, Ya-Wei; Xu, Ying; Su, Wei-Yan; Xu, Xi-ming; Yu, Jiang-Nan

    2012-01-01

    Background The purpose of this study was to develop a sustained drug-release model for water-soluble drugs using silica nanoparticles. Methods Hollow-type mesoporous silica nanoparticles (HMSNs) were prepared using Na2CO3 solution as the dissolution medium for the first time. The water-soluble compound, silybin meglumine, was used as the model drug. The Wagner–Nelson method was used to calculate the in vivo absorption fraction. Results The results of transmission electron microscopy and nitrogen adsorption revealed that the empty HMSNs had uniformly distributed particles of size 50–100 nm, a spherical appearance, a large specific surface area (385.89 ± 1.12 m2/g), and ultralow mean pore size (2.74 nm). The highly porous structure allowed a large drug-loading rate (58.91% ± 0.39%). In 0.08 M Na2CO3 solution, silybin meglumine-loaded HMSNs could achieve highly efficacious and long-term sustained release for 72 hours in vitro. The results of in vitro–in vivo correlation revealed that HMSNs in 0.08 M Na2CO3 solution had a correlation coefficient R2 value of 0.9931, while those of artificial gastric juice and artificial intestinal juice were only 0.9287 and 0.7689, respectively. Conclusion The findings of in vitro–in vivo correlation indicate that HMSNs together with Na2CO3 solution could achieve an excellent linear relationship between in vitro dissolution and in vivo absorption for 72 hours, leading to a promising model for sustained release of water-soluble drugs. PMID:22393284

  17. The effect of quercetin and kaempferol aglycones and glucuronides on peroxisome proliferator-activated receptor-gamma (PPAR-?).

    PubMed

    Beekmann, Karsten; Rubió, Laura; de Haan, Laura H J; Actis-Goretta, Lucas; van der Burg, Bart; van Bladeren, Peter J; Rietjens, Ivonne M C M

    2015-04-01

    The consumption of dietary flavonoids has been associated with a variety of health benefits, including effects mediated by the activation of peroxisome proliferator-activated receptor-gamma (PPAR-?). Flavonoids are extensively metabolized during and after uptake and there is little known on the biological effects of these conjugated metabolites of flavonoids that are found in plasma. To investigate the effect of glucuronidation on the ability of flavonoids to activate PPAR-? we studied and compared the activity of quercetin, kaempferol and their relevant plasma conjugates quercetin-3-O-glucuronide (Q3G) and kaempferol-3-O-glucuronide (K3G) on different PPAR-? related endpoints. The flavonoid aglycones increased PPAR-? mediated gene expression in a stably transfected reporter gene cell line and glucuronidation diminished their effect. To study the intrinsic activity of the test compounds to activate PPAR-? we used a novel microarray technique to study ligand induced ligand binding domain (LBD) - nuclear receptor coregulator interactions. In this cell-free system we demonstrate that, unlike the known PPAR-? agonist rosiglitazone, neither the flavonoid aglycones nor the conjugates are agonistic ligands of the receptor. The increases in reporter gene expression in the reporter cells were accompanied by increased PPAR-? receptor-mRNA expression and quercetin synergistically increased the effect of rosiglitazone in the reporter gene assay. It is concluded that flavonoids affect PPAR-? mediated gene transcription by a mode of action different from agonist binding. Increases in PPAR-? receptor mRNA expression and synergistic effects with endogenous PPAR-? agonists may play a role in this alternative mode of action. Glucuronidation reduced the activity of the flavonoid aglycones. PMID:25765892

  18. A facile one-pot self-assembly approach to incorporate SnOx nanoparticles in ordered mesoporous carbon with soft templating for fuel cells

    NASA Astrophysics Data System (ADS)

    Huang, Yingqiang; Zhai, Zhicheng; Luo, Zhigang; Liu, Yingju; Liang, Zhurong; Fang, Yueping

    2014-04-01

    Unique SnOx (x = 1,2)/ordered mesoporous carbon nanocomposites (denoted as SnOx/OMC) are firstly synthesized through a ‘one-pot’ synthesis together with the soft template self-assembly approach. The obtained SnOx/OMC nanocomposites with various SnOx contents exhibit uniform pore sizes between 3.9 and 4.2 nm, high specific surface areas between 497 and 595 m2 g-1, and high pore volumes between 0.39 and 0.48 cm3 g-1. With loading of Pt, Pt-SnOx/OMC with relatively low SnOx content exhibits superior electrocatalytic performance, long-term durability, and resistance to CO poisoning for methanol oxidation, as compared to Pt/OMC, PtRu/C and Pt-SnOx/C, which may be attributed not only to the synergetic effect of embedded SnOx, but also to the highly ordered mesostructure with high specific surface areas and large pore volumes affording plenty of surface area for support of Pt nanoparticles. This work supplies an efficient way to synthesize novel ordered mesoporous carbon self-supported metallic oxide as catalyst support and its further potential application to reduce the cost of catalysts in direct methanol fuel cells.

  19. 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.

  20. 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

  1. 13C CP MAS NMR and GIAO-CHF/DFT calculations of flavonoids: Morin, kaempferol, tricin, genistein, formononetin and 3,7-dihydroxyflavone

    NASA Astrophysics Data System (ADS)

    Zieli?ska, Agnieszka; Paradowska, Katarzyna; Jakowski, Jacek; Wawer, Iwona

    2008-02-01

    13C CP MAS NMR spectra of the flavonoids: morin, kaempferol, 3,7-dihydroxyflavone, tricin and isoflavones: genistein and formononetin were recorded to characterize solid-state conformations. Intramolecular hydrogen bonds forming five-, six- and seven-membered rings are present in the two morin molecules in the crystals - their 13C resonances have been assigned with the aid of the calculated shielding constants. Linear relationships between the calculated shielding constants ?DFT (ppm) and chemical shifts ( ?CPMAS, ppm) were obtained for all studied compounds. Higher correlation coefficients suggest that the conformation with "clockwise" orientation of both OH groups is more probable in the solid 3,7-dihydroxyflavone, whereas in the solid formononetin the OH and OCH 3 substituents are directed "anticlockwise". The barrier to the rotation of phenyl ring B decreases in the order: morin (2'-OH, 3-OH) > kaempferol (3-OH) > tricin.

  2. A fragmentation study of kaempferol using electrospray quadrupole time-of-flight mass spectrometry at high mass resolution

    NASA Astrophysics Data System (ADS)

    March, Raymond E.; Miao, Xiu-Sheng

    2004-02-01

    A mass spectrometric method based on the combined use of electrospray ionization, collision-induced dissociation and tandem mass spectrometry at high mass resolution has been applied to an investigation of the structural characterization of protonated and deprotonated kaempferol (3,5,7,4'-tetrahydroxyflavone). Low-energy product ion mass spectra of [M+H]+ ions showed simple fragmentations of the C ring that permitted characterization of the substituents in the A and B rings. In addition, four rearrangement reactions accompanied by losses of C2H2O, CHO[radical sign], CO, and H2O were observed. Low-energy product ion mass spectra of [M-H]- ions showed only four rearrangement reactions accompanied by losses of OH[radical sign], CO, CH2O, and C2H2O. The use of elevated cone voltages permitted observation of product ion mass spectra of selected primary and secondary fragment ions so that each fragment ion reported was observed as a direct product of its immediate precursor ion. Product ion mass spectra examined at high mass resolution allowed unambiguous determination of the elemental composition of fragment ions and resolution of two pairs of isobars. Fragmentation mechanisms and ion structures have been proposed.

  3. 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

  4. Kaempferol attenuates the glutamate-induced oxidative stress in mouse-derived hippocampal neuronal HT22 cells.

    PubMed

    Yang, Eun-Ju; Kim, Geum-Soog; Jun, Mira; Song, Kyung-Sik

    2014-07-25

    It is thought that the neuronal cell loss caused by oxidative stress is the primary mechanism underlying the pathogenesis of several neurodegenerative disorders. Glutamate is an endogenous neurotransmitter, but at high concentrations it can act as a neurotoxicant by increasing the intracellular levels of reactive oxygen species (ROS). Therefore, the development of factors that can attenuate glutamate-induced oxidative stress in neuronal cells is a good strategy by which new drugs could be discovered that may treat or prevent neurodegenerative diseases. Here, the neuroprotective effects of kaempferol (KF) isolated from the stems of butterbur (Petasites japonicus) were examined in glutamate-treated hippocampal neuronal cells (HT22). The administration of KF (25 ?M) resulted in a significant increase in cell viability (105.18 ± 7.48%) compared with the control (100.00 ± 3.05%), while glutamate (5 mM) reduced cell viability by 39.94 ± 1.61%. The glutamate-induced calcium (Ca(2+)) influx (1.93 ± 0.08-fold) was significantly reduced by 0.89 ± 0.02-fold following the administration of 25 ?M KF. Additionally, when HT22 cells were stressed with excessive glutamate, there was a 3.70 ± 0.01-fold increase in intracellular ROS generation, even though this was effectively attenuated by KF (25 ?M, 0.72 ± 0.01-fold). The protective effects of KF in HT22 cells were later confirmed using a lactate dehydrogenase (LDH) assay and a FITC-annexin V/propidium iodide double staining procedure. These findings also revealed that the neuroprotective effects of KF are a result of the regulation of the expression levels of proteins, such as Bcl-2, Bid, apoptosis-inducing factor (AIF), and mitogen-activated protein kinase (MAPK). This is the first report to investigate the neuroprotective influence of KF in glutamate-treated HT22 cells. These data demonstrate that KF may be a useful candidate for pharmacological therapies that can prevent and treat neurodegenerative diseases such as Alzheimer's disease (AD). PMID:24770605

  5. Kaempferol 3-O-rhamnoside-7-O-rhamnoside is an endogenous flavonol inhibitor of polar auxin transport in Arabidopsis shoots

    PubMed Central

    Yin, Ruohe; Han, Kerstin; Heller, Werner; Albert, Andreas; Dobrev, Petre I; Zažímalová, Eva; Schäffner, Anton R

    2014-01-01

    Polar auxin transport (PAT) plays key roles in the regulation of plant growth and development. Flavonoids have been implicated in the inhibition of PAT. However, the active flavonoid derivative(s) involved in this process in vivo has not yet been identified. Here, we provide evidence that a specific flavonol bis-glycoside is correlated with shorter plant stature and reduced PAT. Specific flavonoid-biosynthetic or flavonoid-glycosylating steps were genetically blocked in Arabidopsis thaliana. The differential flavonol patterns established were analyzed by high-performance liquid chromatography (HPLC) and related to altered plant stature. PAT was monitored in stem segments using a radioactive [3H]-indole-3-acetic acid tracer. The flavonoid 3-O-glucosyltransferase mutant ugt78d2 exhibited a dwarf stature in addition to its altered flavonol glycoside pattern. This was accompanied by reduced PAT in ugt78d2 shoots. The ugt78d2-dependent growth defects were flavonoid dependent, as they were rescued by genetic blocking of flavonoid biosynthesis. Phenotypic and metabolic analyses of a series of mutants defective at various steps of flavonoid formation narrowed down the potentially active moiety to kaempferol 3-O-rhamnoside-7-O-rhamnoside. Moreover, the level of this compound was negatively correlated with basipetal auxin transport. These results indicate that kaempferol 3-O-rhamnoside-7-O-rhamnoside acts as an endogenous PAT inhibitor in Arabidopsis shoots. PMID:24251900

  6. 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

    2015-03-11

    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 A1c) levels and improved insulin resistance. Gene expression analysis of the liver showed that KG decreased peroxisome proliferator-activated receptor (PPAR-?) 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-? and SREBP-1c. Thus, KG may have an anti-obesity and anti-diabetic potential. PMID:25599885

  7. 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.

  8. Nanoparticles for Imaging: Top or Flop?

    PubMed Central

    Kiessling, Fabian; 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

  9. 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

  10. Electrochemical response of ZrO 2-incorporated oxide layer on AZ91 Mg alloy processed by plasma electrolytic oxidation

    Microsoft Academic Search

    Kang Min Lee; Ki Ryong Shin; Seung Namgung; Bongyoung Yoo; Dong Hyuk Shin

    2011-01-01

    ZrO2 nanoparticles well dispersed in an electrolyte were effectively incorporated in an oxidized surface passivation layer on AZ91 Mg alloy by a plasma electrolytic oxidation (PEO) process. The electrophoretic reaction and mechanical mixing in molten magnesium oxide were the main factors leading to incorporation of ZrO2 nanoparticles in the magnesium oxide layer. Incorporated ZrO2 nanoparticles were mainly located in pores

  11. Functionalizable Amine-based Polymer Nanoparticles

    PubMed Central

    Wang, Hui; Zhuang, Jiaming; Thayumanavan, S.

    2014-01-01

    Surface functionalization of nanoparticles and host-guest properties of nanoassemblies are two critical features in the utilization of nanostructures in a variety of applications in materials, chemical, and biological nanotechnology. However, simultaneously incorporating these two features in one nanoparticle design is a rather challenging task. We have developed a simple and versatile nanoparticle platform that addresses this challenge. We have designed and characterized a polymer nanoparticle that provides the ability to encapsulate hydrophobic guest molecules and surface functionalization with a wide range of functional groups. In addition, we have also demonstrated a new and simple approach to tune the size of the nanoparticles. PMID:25580372

  12. Bioassay-guided isolation of kaempferol-3-O-beta-D-galactoside with anti-inflammatory and antinociceptive activity from the aerial part of Calluna vulgaris L.

    PubMed

    Orhan, I; Küpeli, E; Terzio?lu, S; Yesilada, E

    2007-10-01

    Calluna vulgaris L. (Ericaceae) is used for the treatment of various inflammatory ailments in traditional medicines. In order to evaluate this ethnobotanical information, its anti-inflammatory and antinociceptive activities were studied using in vivo experimental models in mice. The ethanolic extract of the plant was first fractionated into five extracts; namely, n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol, and water fractions. Among them, the EtOAc Fr. was found to be the most effective and was further subjected to bioassay-guided fractionation and isolation procedures. After successive column chromatography applications, on Sephadex LH-20 and silica gel, a component, which is responsible for the above-mentioned activities of this species of Turkish origin, was isolated and its structure was elucidated as kaempferol-3-O-beta-D-galactoside, a common flavonol derivative by means of spectral techniques. PMID:17765419

  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-?-d-glucopyranosyl-(1-2)-?-d-glucopyranoside and quercetin-3-O-?-d-glucopyranosyl-(1-2)-?-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. Inhibitory effects of kaempferol-3-O-rhamnoside on ovalbumin-induced lung inflammation in a mouse model of allergic asthma.

    PubMed

    Chung, Mi Ja; Pandey, Ramesh Prasad; Choi, Ji Won; Sohng, Jae Kyung; Choi, Doo Jin; Park, Yong Il

    2015-04-01

    The modification of natural flavonoid by glycosylation alters their physicochemical and pharmacokinetic properties, such as increased water solubility and stability, reduced toxicity, and sometimes enhanced or even new pharmacological activities. Kaempferol (KF), a plant flavonoid, and its glycosylated derivative, kaempferol-3-O-rhamnoside (K-3-rh), were evaluated and compared for their anti-inflammatory, anti-oxidant, and anti-asthmatic effects in an asthma model mouse. The results showed that K-3-rh fully maintained its anti-inflammatory and anti-asthmatic effects compared with KF in an asthma model mouse. Both KF and K-3-rh significantly reduced the elevated inflammatory cell numbers in the bronchoalveolar lavage fluid (BALF). KF and K-3-rh also significantly inhibited the increase in Th2 cytokines (IL-4, IL-5, and IL-13) and TNF-? protein levels through inhibition of the phosphorylation Akt and effectively suppressed eosinophilia in a mouse model of allergic asthma. The total immunoglobulin (Ig) E levels in the serum and BALF were also blocked by KF and K-3-rh to similar extents. K-3-rh exerts similar or even slightly higher inhibitory effects on Th2 cytokines and IgE production compared with KF, whereas K-3-rh was less effective at DPPH radical scavenging and the inhibition of ROS generation in inflammatory cells compared with KF. These results suggested that the K-3-rh, as well as KF, may also be a promising candidate for the development of health beneficial foods or therapeutic agents that can prevent or treat allergic asthma. PMID:25698556

  15. 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

  16. 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.

  17. 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...

  18. Effects of Parsley (Petroselinum crispum) and its Flavonol Constituents, Kaempferol and Quercetin, on Serum Uric Acid Levels, Biomarkers of Oxidative Stress and Liver Xanthine Oxidoreductase Aactivity inOxonate-Induced Hyperuricemic Rats

    PubMed Central

    Haidari, Fatemeh; Keshavarz, Seid Ali; Mohammad Shahi, Majid; Mahboob, Soltan-Ali; Rashidi, Mohammad-Reza

    2011-01-01

    Increased serum uric acid is known to be a major risk related to the development of several oxidative stress diseases. The aim of this study was to investigate the effect of parsley, quercetin and kaempferol on serum uric acid levels, liver xanthine oxidoreductase activity and two non-invasive biomarkers of oxidative stress (total antioxidant capacity and malondialdehyde concentration) in normal and oxonate-induced hyperuricemic rats. A total of 60 male Wistar rats were randomly divided into ten equal groups; including 5 normal groups (vehicle, parsley, quercetin, kaempferol and allopurinol) and 5 hyperuricemic groups (vehicle, parsley, quercetin, kaempferol and allopurinol). Parsley (5 g/Kg), quercetin (5 mg/Kg), kaempferol (5 mg/Kg) and allopurinol (5 mg/Kg) were administrated to the corresponding groups by oral gavage once a day for 2 weeks. The results showed that parsley and its flavonol did not cause any significant reduction in the serum uric acid levels in normal rats, but significantly reduced the serum uric acid levels of hyperuricemic rats in a time-dependent manner. All treatments significantly inhibited liver xanthine oxidoreductase activity. Parsley, kaempferol and quercetin treatment led also to a significant increase in total antioxidant capacity and decrease in malondialdehyde concentration in hyperuricemic rats. Although the hypouricemic effect of allopurinol was much higher than that of parsley and its flavonol constituents, it could not significantly change oxidative stress biomarkers. These features of parsley and its flavonols make them as a possible alternative for allopurinol, or at least in combination therapy to minimize the side effects of allopurinol to treat hyperuricemia and oxidative stress diseases. PMID:24250417

  19. Boronate affinity nanoparticles for RNA isolation.

    PubMed

    Toprak, Aykut; Görgün, Cansu; Kuru, Cansu ?lke; 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 5cycles. PMID:25746268

  20. 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...

  1. 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...

  2. Incorporation effect of nanosized perovskite LaFe{sub 0.7}Co{sub 0.3}O{sub 3} on the electrochemical activity of Pt nanoparticles-multi walled carbon nanotube composite toward methanol oxidation

    SciTech Connect

    Noroozifar, Meissam, E-mail: mnoroozifar@chem.usb.ac.ir [Department of Chemistry, University of Sistan and Baluchestan, PO Box 98155-147, Zahedan (Iran, Islamic Republic of); Khorasani-Motlagh, Mozhgan; Khaleghian-Moghadam, Roghayeh; Ekrami-Kakhki, Mehri-Saddat; Shahraki, Mohammad [Department of Chemistry, University of Sistan and Baluchestan, PO Box 98155-147, Zahedan (Iran, Islamic Republic of)

    2013-05-15

    Nanosized perovskite LaFe{sub 0.7}Co{sub 0.3}O{sub 3} (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 LaFe{sub 0.7}Co{sub 0.3}O{sub 3} 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 LaFe{sub 0.7}Co{sub 0.3}O{sub 3} (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.

  3. Engineering biofunctional magnetic nanoparticles for biotechnological applications

    NASA Astrophysics Data System (ADS)

    Moros, Maria; Pelaz, Beatriz; López-Larrubia, Pilar; García-Martin, Maria L.; Grazú, 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

  4. 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.

  5. Design and characterization of protein-quercetin bioactive nanoparticles

    PubMed Central

    2011-01-01

    Background The synthesis of bioactive nanoparticles with precise molecular level control is a major challenge in bionanotechnology. Understanding the nature of the interactions between the active components and transport biomaterials is thus essential for the rational formulation of bio-nanocarriers. The current study presents a single molecule of bovine serum albumin (BSA), lysozyme (Lys), or myoglobin (Mb) used to load hydrophobic drugs such as quercetin (Q) and other flavonoids. Results Induced by dimethyl sulfoxide (DMSO), BSA, Lys, and Mb formed spherical nanocarriers with sizes less than 70 nm. After loading Q, the size was further reduced by 30%. The adsorption of Q on protein is mainly hydrophobic, and is related to the synergy of Trp residues with the molecular environment of the proteins. Seven Q molecules could be entrapped by one Lys molecule, 9 by one Mb, and 11 by one BSA. The controlled releasing measurements indicate that these bioactive nanoparticles have long-term antioxidant protection effects on the activity of Q in both acidic and neutral conditions. The antioxidant activity evaluation indicates that the activity of Q is not hindered by the formation of protein nanoparticles. Other flavonoids, such as kaempferol and rutin, were also investigated. Conclusions BSA exhibits the most remarkable abilities of loading, controlled release, and antioxidant protection of active drugs, indicating that such type of bionanoparticles is very promising in the field of bionanotechnology. PMID:21586116

  6. 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 ...

  7. GENDER EQUALITY Incorporated

    E-print Network

    Barthelat, Francois

    , gender roles, gender construction Gender mythsGENDER EQUALITY Incorporated 5 DAY GENDER TRAINING WITH CERTIFICATION April 26-30, 2010 - Toronto. #12;simplifying IT 5 DAY GENDER TRAINING WITH CERTIFICATION GOAL This 5 day course is designed

  8. 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.

  9. 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...

  10. Separation of patuletin-3-O-glucoside, astragalin, quercetin, kaempferol and isorhamnetin from Flaveria bidentis (L.) Kuntze by elution-pump-out high-performance counter-current chromatography.

    PubMed

    Wei, Yun; Xie, Qianqian; Fisher, Derek; Sutherland, Ian A

    2011-09-01

    Flaveria bidentis (L.) Kuntze is an annual alien weed of Flaveria Juss. (Asteraceae) in China. Bioactive compounds, mainly flavonol glycosides and flavones from F. bidentis (L.) Kuntze, have been studied in order to utilize this invasive weed, Analytical high-performance counter-current chromatography (HPCCC) was successfully used to separate patuletin-3-O-glucoside, a mixture of hyperoside (quercetin-3-O-galactoside) and 6-methoxykaempferol-3-O-galactoside, astragalin, quercetin, kaempferol and isorhamnetin using two runs with different solvent system. Ethyl acetate-methanol-water (10:1:10, v/v) was selected by analytical HPCCC as the optimum phase system for the separation of patuletin-3-O-glucoside, a mixture of hyperoside and 6-methoxykaempferol-3-O-galactoside, and astragalin. A Dichloromethane-methanol-water (5:3:2, v/v) was used for the separation of quercetin, kaempferol and isorhamnetin. The separation was then scaled up: the crude extract (ca 1.5 g) was separated by preparative HPCCC, yielding 12 mg of patuletin-3-O-glucoside at a purity of 98.3%, yielding 9 mg of a mixture of hyperoside and 6-methoxykaempferol-3-O-galactoside constituting over 98% of the fraction, and 16 mg of astragalin (kaempferol-3-O-glucoside) at a purity of over 99%. The pump-out peaks are isorhanetin (98% purity), kaemferol (93% purity) and quercitin (99% purity). The chemical structure of patuletin-3-O-glucoside and astragalin were confirmed by MS and ¹H, ¹³C NMR. PMID:21329934

  11. Allergen immunotherapy with nanoparticles containing lipopolysaccharide from Brucella ovis

    Microsoft Academic Search

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

    2008-01-01

    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

  12. 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

  13. 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

  14. 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

  15. Superparamagnetic Nanoparticles

    Microsoft Academic Search

    Boon Hoong Ong; Nisha Kumari Devaraj

    \\u000a Nanoscaled magnetic materials are great candidates for fundamental and applied research. 0D, 1D and 2D magnetic nanostructures\\u000a have been extensively studied previously. One of the unique phenomena that only exists in nanoscaled magnetic structure (below\\u000a a certain critical size) is superparamagnetism. In this chapter, various chemical synthesis methods to obtain superparamagnetic\\u000a nanoparticles are compared. Strategies to prevent agglomeration of nanoparticles

  16. 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

  17. Poly( d, l-lactide-co-glycolide)\\/montmorillonite nanoparticles for oral delivery of anticancer drugs

    Microsoft Academic Search

    Yuancai Dong; Si-Shen Feng

    2005-01-01

    This research developed a novel bioadhesive drug delivery system, poly(d,l-lactide-co-glycolide)\\/montmorillonite (PLGA\\/MMT) nanoparticles, for oral delivery of paclitaxel. Paclitaxel-loaded PLGA\\/MMT nanoparticles were prepared by the emulsion\\/solvent evaporation method. MMT was incorporated in the formulation as a matrix material component, which also plays the role of a co-emulsifier in the nanoparticle preparation process. Paclitaxel-loaded PLGA\\/MMT nanoparticles were found to be of spherical

  18. Zinc Incorporation Into Hydroxylapatite

    SciTech Connect

    Tang, Y.; Chappell, H; Dove, M; Reeder, R; Lee, Y

    2009-01-01

    By theoretical modeling and X-ray absorption spectroscopy, the local coordination structure of Zn incorporated into hydroxylapatite was examined. Density function theory (DFT) calculations show that Zn favors the Ca2 site over the Ca1 site, and favors tetrahedral coordination. X-ray absorption near edge structure (XANES) spectroscopy results suggest one dominant coordination environment for the incorporated Zn, and no evidence was observed for other Zn-containing phases. Extended X-ray absorption fine structure (EXAFS) fitting of the synthetic samples confirms that Zn occurs in tetrahedral coordination, with two P shells at 2.85-3.07 {angstrom}, and two higher Ca shells at 3.71-4.02 {angstrom}. These fit results are consistent with the most favored DFT model for Zn substitution in the Ca2 site.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Incorporation of silica into baroplastic core-shell nanoparticles

    E-print Network

    Hewlett, Sheldon A

    2006-01-01

    Core-shell baroplastics are nanophase materials that exhibit pressure-induced flow at low temperatures and high pressures. Core-shell baroplastics used in this work are comprised of a low Tg poly(butyl acrylate) (PBA) core ...

  4. 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

  5. Dendrimer-based nanoparticles for cancer therapy

    Microsoft Academic Search

    James R. Baker Jr

    Recent work has suggested that nanoparticles in the form of dendrimers may be a keystone in the future of therapeutics. The field of oncology could soon be revolutionized by novel strategies for diagnosis and therapy employing dendrimer-based nanotherapeutics. Several aspects of cancer therapy would be involved. Diagnosis using imaging techniques such as MRI will be improved by the incorporation of

  6. Imparting functionality to a metalorganic framework material by controlled nanoparticle

    E-print Network

    solvents. MOFs have crystal- line structures and typically are characterized by large internal surface, dispersed nature, spatial distribution and confinement of the incorporated nanoparticles within MOF matrices confined within the ZIF-8 crystals. This strategy also allows the controlled incorporation of multiple

  7. The effects of 100 nm-diameter Au nanoparticles on dye-sensitized solar Changwoo Nahm,1

    E-print Network

    Park, Byungwoo

    attributed to the photocurrent density. The Au nanoparticles embedded in the nanoparticulate-TiO2 film online 22 December 2011) Gold nanoparticles of $100 nm in diameter were incorporated into TiO2 nanoparticles for dye-sensitized solar cells (DSSCs). At the optimum Au/TiO2 mass ratio of 0.05, the power

  8. Recovery and redispersion of gold nanoparticles using the self-assembly of a pH sensitive zwitterionic amphiphile.

    PubMed

    Morita-Imura, Clara; Imura, Yoshiro; Kawai, Takeshi; Shindo, Hitoshi

    2014-11-01

    The pH-responsive self-assembly of zwitterionic amphiphile C16CA was expanded to the recovery of gold (Au) nanoparticles for environmentally friendly chemistry applications. Multilayered lamellae at pH ? 4 were successfully incorporated into nanoparticles by dispersion. Redispersion of nanoparticles was achieved under basic conditions by the transition of self-assembly. PMID:25219607

  9. 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.

  10. Mixing Effect of Gold and Silver Nanoparticles on Enhancement in Performance of Organic Thin-Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Akiyama, Tsuyoshi; Yamamoto, Tomoki; Oku, Takeo; Yahiro, Masayuki; Kurihara, Takashi; Adachi, Chihaya; Yamada, Sunao

    2013-12-01

    Bulk-heterojunction organic thin-film solar cells incorporating gold and silver nanoparticles were fabricated and evaluated. These nanoparticles were embedded in the hole-transport layer of the solar cells. Plasmonic absorption peaks of isolated gold and silver nanoparticles were confirmed from extinction spectra even in the hole-transport material. The incorporation of gold and silver nanoparticles increased the photoelectric conversion efficiency of organic thin-film solar cells, whose enhancement ratio was further increased by mixing gold and silver nanoparticles.

  11. Functionalized mesoporous silica nanoparticles for oral delivery of budesonide

    NASA Astrophysics Data System (ADS)

    Yoncheva, K.; Popova, M.; Szegedi, A.; Mihaly, J.; Tzankov, B.; Lambov, N.; Konstantinov, S.; Tzankova, V.; Pessina, F.; Valoti, M.

    2014-03-01

    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.

  12. 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?250nm), 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

  13. Nanoparticle-directed self-assembly of amphiphilic block-copolymers

    NASA Astrophysics Data System (ADS)

    Park, So-Jung

    2011-03-01

    The self-assembly of nanoparticles and amphiphilic polymers provides a powerful tool for the fabrication of functional composite materials for a range of applications spanning from nanofabrication to medicine. Here, we present how the incorporation of nanoparticles affects the self-assembly behavior of amphiphilic block-copolymers and how to control the morphology of nanoparticle-encapsulating polymer assemblies. Based on the approach, we have prepared various types of well-defined nanoparticle-encapsulating polymeric nanostructures, including polymersomes packed with magnetic nanoparticles and unique cavity-like quantum dot assembles. We found that the incorporation of nanoparticles drastically affects the self-assembly structure of block-copolymers by modifying the relative volume ratio between the hydrophobic block and the hydrophilic block. In addition, the nanoparticle-polymer and nanoparticle-solvent interactions impact the arrangement and the hybridization of nanoparticles in polymer matrix. These findings should form the basis for the design rules of the self-assembly of nanoparticles and polymer amphiphiles, which will allow one to create new hybrid structures with predesigned morphology and properties. Furthermore, we demonstrated that the morphology of nanoparticle-encapsulating polymer assemblies significantly affects their properties such as magnetic relaxation properties, underscoring the importance of the overall self-assembly structure and the nanoparticle arrangement in polymer matrixes.

  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. Incorporation of pyrene in polypyrrole/polystyrene magnetic beads.

    PubMed

    G?owala, Paulina; Budniak, Adam; Krug, Pamela; Wysocka, Barbara; Berbe?, Sylwia; Dec, Robert; Do??ga, Izabela; Kacprzak, Kamil; Wojciechowski, Jaros?aw; Kawa?ko, Jakub; K?pka, Pawe?; K?pi?ska, Daria; Kijewska, Krystyna; Mazur, Maciej

    2014-10-15

    Pyrene, a fluorescent dye, was incorporated into polystyrene particles coated with polypyrrole. The incorporation was achieved by treating the polypyrrole/polystyrene (PPy/PS) beads in a tetrahydrofuran (THF) solution of the pyrene fluorophore followed by rinsing with methanol. The polystyrene cores of the beads swell in THF, allowing penetration of pyrene molecules into the polystyrene structure. The addition of methanol causes contraction of the swollen polystyrene, which encapsulates the dye molecules inside the beads. It is shown that the polypyrrole coating is permeable with respect to both the dye and the solvent, allowing the transport of molecules between the polystyrene cores and the contacting solution. The polypyrrole adlayer can be used as a matrix for the incorporation of magnetic nanoparticles. Embedded particles provide magnetic functionality to the PPy/PS beads. It is demonstrated that the pyrene-loaded beads can be manipulated with an external magnetic field. PMID:24854245

  17. Incorporation of pyrene in polypyrrole/polystyrene magnetic beads

    NASA Astrophysics Data System (ADS)

    G?owala, Paulina; Budniak, Adam; Krug, Pamela; Wysocka, Barbara; Berbe?, Sylwia; Dec, Robert; Do??ga, Izabela; Kacprzak, Kamil; Wojciechowski, Jaros?aw; Kawa?ko, Jakub; K?pka, Pawe?; K?pi?ska, Daria; Kijewska, Krystyna; Mazur, Maciej

    2014-10-01

    Pyrene, a fluorescent dye, was incorporated into polystyrene particles coated with polypyrrole. The incorporation was achieved by treating the polypyrrole/polystyrene (PPy/PS) beads in a tetrahydrofuran (THF) solution of the pyrene fluorophore followed by rinsing with methanol. The polystyrene cores of the beads swell in THF, allowing penetration of pyrene molecules into the polystyrene structure. The addition of methanol causes contraction of the swollen polystyrene, which encapsulates the dye molecules inside the beads. It is shown that the polypyrrole coating is permeable with respect to both the dye and the solvent, allowing the transport of molecules between the polystyrene cores and the contacting solution. The polypyrrole adlayer can be used as a matrix for the incorporation of magnetic nanoparticles. Embedded particles provide magnetic functionality to the PPy/PS beads. It is demonstrated that the pyrene-loaded beads can be manipulated with an external magnetic field.

  18. Nanoengineered silicon/silicon dioxide nanoparticle heterostructures

    NASA Astrophysics Data System (ADS)

    Ostraat, Michele L.; Brongersma, Mark; Atwater, Harry A.; Flagan, Richard C.

    2005-07-01

    Engineering control of nanostructures is becoming increasingly important as nanotechnology applications develop and as device features shrink. In many nanotechnology-driven applications, bottoms-up fabrication of devices offers many inherent advantages over conventional top-down approaches typically employed today. In order to be commercially viable, bottoms-up fabrication methodologies must rely upon the synthesis and assembly of nanoengineered structures. The silicon nanoparticle-based floating-gate metal-oxide-semiconductor field effect transistor is an example of a device that incorporates nanostructures and is an attractive candidate for terabit cm -2 density nonvolatile memory applications. However, variability in the size, location, and interface electronic quality of the nanoparticles in an ensemble limits device performance. To reduce device variability, the Si nanoparticle layer can be fabricated using a bottoms-up approach. Aerosol Si nanoparticles are synthesized by thermal decomposition of silane gas in a reactor optimized to produce spherical, single-crystal, nonagglomerated nanoparticles. The aerosol nanoparticles are size-classified with a differential mobility analyzer to produce narrow size distributions. Uniform oxide layers in the nanometer thickness range are then formed on the Si nanoparticles, either by thermal oxidation or by aerosol vapor phase tetraethylorthosilicate deposition. Electronic measurements indicate that high temperature thermal SiO 2 and deposited tetraethylorthosilicate-derived SiO 2 form shells of sufficient quality and thickness to isolate electrically adjacent nanoparticles from each other. Photoluminescence measurements used to probe the Si/SiO 2 interface indicate the presence of a high quality interface between deposited tetraethylorthosilicate oxide and Si nanoparticles.

  19. 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 ˜95°C. 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.

  20. Development of intracanal formulation containing silver nanoparticles.

    PubMed

    Bruniera, João Felipe Bonatto; Silva-Sousa, Yara Teresinha Corrêa; Lara, Marilisa Guimarães; Pitondo-Silva, André; Marcaccini, Andrea Marcia; Miranda, Carlos Eduardo Saraiva

    2014-01-01

    This study aimed to synthetize, characterize and evaluate the antimicrobial properties of silver nanoparticles to be used in the development of a root intracanal formulation. Silver nanoparticles (AgNPs) were obtained by reduction of silver nitrate with sodium borohydride and characterized by UV-Visible spectrophotometry, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The antimicrobial activity of nanoparticle formulation was evaluated by determinations of the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against different bacterial species by the microdilution method, according to recommendations of the Clinical and Laboratory Standards Institute (CLSI). Three potential vehicles, hydroxyethylcellulose, Carbomer and polyethylene glycol were tested as carriers for formulations containing AgNPs. The efficiency of the synthesis method chosen to produce AgNPs was demonstrated by four characterization techniques. The nanoparticles showed antibacterial activity against all species tested. Incorporation of AgNPs into all experimental vehicles produced stable formulations but the one in hydroxyethylcellulose presented better physical proprieties. The results indicate that silver nanoparticles are potential antiseptic agents to be used in root canals and incorporation in adequate vehicles may favor a broader application. PMID:25250493

  1. Application of metal nanoparticles decorated carbon nanotubes in photovoltaics

    Microsoft Academic Search

    Prakash R. Somani; Savita P. Somani; M. Umeno

    2008-01-01

    Carbon nanotubes decorated with metal nanoparticles are introduced to photovoltaic application. The introduction of metal nanoparticles in the organic\\/organic-inorganic heterojunction solar cells is expected to improve the exciton dissociation (due to strong electric field at the metal-organics interface) and hence photovoltaic action. An improved photovoltaic action is indeed observed in n-Si\\/poly(3-octylthiophene) heterojunction solar cells incorporating multiwalled carbon nanotubes (MWCN) decorated

  2. Porous Collagen Scaffold Reinforced with Surfaced Activated PLLA Nanoparticles

    PubMed Central

    Xu, Cancan; Lu, Wei; Bian, Shaoquan; Liang, Jie; Fan, Yujiang; Zhang, Xingdong

    2012-01-01

    Porous collagen scaffold is integrated with surface activated PLLA nanoparticles fabricated by lyophilizing and crosslinking via EDC treatment. In order to prepare surface-modified PLLA nanoparticles, PLLA was firstly grafted with poly (acrylic acid) (PAA) through surface-initiated polymerization of acrylic acid. Nanoparticles of average diameter 316?nm and zeta potential ?39.88?mV were obtained from the such-treated PLLA by dialysis method. Porous collagen scaffold were fabricated by mixing PLLA nanoparticles with collagen solution, freeze drying, and crosslinking with EDC. SEM observation revealed that nanoparticles were homogeneously dispersed in collagen matrix, forming interconnected porous structure with pore size ranging from 150 to 200??m, irrespective of the amount of nanoparticles. The porosity of the scaffolds kept almost unchanged with the increment of the nanoparticles, whereas the mechanical property was obviously improved, and the degradation was effectively retarded. In vitro L929 mouse fibroblast cells seeding and culture studies revealed that cells infiltrated into the scaffolds and were distributed homogeneously. Compared with the pure collagen sponge, the number of cells in hybrid scaffolds greatly increased with the increment of incorporated nanoparticles. These results manifested that the surface-activated PLLA nanoparticles effectively reinforced the porous collagen scaffold and promoted the cells penetrating into the scaffold, and proliferation. PMID:22448137

  3. 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…

  4. Photochemical Incorporation of Silver Quantum Dots in Monodisperse Silica Colloids for Photonic Crystal Applications

    E-print Network

    Asher, Sanford A.

    sphere to a maximum diameter of 55 nm. In addition, these silver-silica core-shell composite particlesPhotochemical Incorporation of Silver Quantum Dots in Monodisperse Silica Colloids for Photonic nanoparticles may be decreasing the silica-silver nanodot composite refractive index below that of the water

  5. High-Throughput Screening Platform for Engineered Nanoparticle-Mediated Genotoxicity Using CometChip Technology

    E-print Network

    Watson, Christa

    The likelihood of intentional and unintentional engineered nanoparticle (ENP) exposure has dramatically increased due to the use of nanoenabled products. Indeed, ENPs have been incorporated in many useful products and have ...

  6. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    NASA Astrophysics Data System (ADS)

    Anantachaisilp, Suranan; Meejoo Smith, Siwaporn; Treetong, Alongkot; Pratontep, Sirapat; Puttipipatkhachorn, Satit; Rungsardthong Ruktanonchai, Uracha

    2010-03-01

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of ?-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812® as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the ?-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance (1H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the 1H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of ?-oryzanol inside the lipid nanoparticles, the 1H-NMR revealed that the chemical shifts of the liquid lipid in ?-oryzanol loaded systems were found at rather higher field than those in ?-oryzanol free systems, suggesting incorporation of ?-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of ?-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of ?-oryzanol and lipids (solid and liquid) inside the lipid nanoparticle systems are proposed.

  7. Modeling the effects of nanoparticles on neuronal cells: From ionic channels to network dynamics

    Microsoft Academic Search

    Michael Busse; Annette Kraegeloh; David Stevens; Christian Cavelius; Jens Rettig; Eduard Arzt; Daniel J. Strauss

    2010-01-01

    Engineered nanoparticles (NPs) offer great application potential in various fields, for example the chemical industry, energy management or medical sciences. Nanoparticles are increasingly being incorporated into daily products. But what happens, if living organisms are exposed to those NPs? Their ability to move seemingly barrier-free in organic tissue could be both beneficial and harmful. Even though research concerning nanotoxicity has

  8. Targeted delivery of multifunctional magnetic nanoparticles.

    PubMed

    McCarthy, Jason R; Kelly, Kimberly A; Sun, Eric Y; Weissleder, Ralph

    2007-04-01

    Magnetic nanoparticles and their magnetofluorescent analogues have become important tools for in vivo imaging using magnetic resonance imaging and fluorescent optical methods. A number of monodisperse magnetic nanoparticle preparations have been developed over the last decade for angiogenesis imaging, cancer staging, tracking of immune cells (monocyte/macrophage, T cells) and for molecular and cellular targeting. Phage display and data mining have enabled the procurement of novel tissue- or receptor-specific peptides, while high-throughput screening of diversity-oriented synthesis libraries has identified small molecules that permit or prevent uptake by specific cell types. Next-generation magnetic nanoparticles are expected to be truly multifunctional, incorporating therapeutic functionalities and further enhancing an already diverse repertoire of capabilities. PMID:17716118

  9. 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, 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 Fe(2+) site with Co(2+), with up to 17 per cent Co substituted into tetrahedral sites. PMID:23594814

  10. 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

  11. Retention of gold nanoparticles in the structure of quasinematic layers formed by DNA molecules

    Microsoft Academic Search

    S. G. Skuridin; V. A. Dubinskaya; E. V. Shtykova; V. V. Volkov; V. M. Rudoy; O. V. Dement’eva; V. A. Kuzmin; E. S. Lisitsyna; S. T. Zakhidov; I. A. Zelenina; Yu. M. Yevdokimov

    2011-01-01

    Gold nanoparticles are shown to get incorporated into double-stranded DNA molecules forming quasinematic layers in the cholesteric\\u000a liquid-crystalline dispersion particles. The process of nanoparticle incorporation results in distortion in an ordered arrangement\\u000a of the neighboring dsDNA molecules in a layer and in global spatial structure of particles of the dispersion, which may be\\u000a one of the possible causes of the

  12. 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

  13. 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

  14. Delineating the pathways for the site-directed synthesis of individual nanoparticles on surfaces

    PubMed Central

    Liu, Guoliang; Eichelsdoerfer, Daniel J.; Rasin, Boris; Zhou, Yu; Brown, Keith A.; Liao, Xing; Mirkin, Chad A.

    2013-01-01

    Although nanoparticles with exquisite properties have been synthesized for a variety of applications, their incorporation into functional devices is challenging owing to the difficulty in positioning them at specified sites on surfaces. In contrast with the conventional synthesis-then-assembly paradigm, scanning probe block copolymer lithography can pattern precursor materials embedded in a polymer matrix and synthesize desired nanoparticles on site, offering great promise for incorporating nanoparticles into devices. This technique, however, is extremely limited from a materials standpoint. To develop a materials-general method for synthesizing nanoparticles on surfaces for broader applications, a mechanistic understanding of polymer-mediated nanoparticle formation is crucial. Here, we design a four-step synthetic process that enables independent study of the two most critical steps for synthesizing single nanoparticles on surfaces: phase separation of precursors and particle formation. Using this process, we elucidate the importance of the polymer matrix in the diffusion of metal precursors to form a single nanoparticle and the three pathways that the precursors undergo to form nanoparticles. Based on this mechanistic understanding, the synthetic process is generalized to create metal (Au, Ag, Pt, and Pd), metal oxide (Fe2O3, Co2O3, NiO, and CuO), and alloy (AuAg) nanoparticles. This mechanistic understanding and resulting process represent a major advance in scanning probe lithography as a tool to generate patterns of tailored nanoparticles for integration with solid-state devices. PMID:23277538

  15. Photothermal guidance for selective photothermolysis with nanoparticles

    NASA Astrophysics Data System (ADS)

    Zharov, Vladimir P.; Galitovskaya, Elena; Viegas, Mark

    2004-07-01

    Photothermal (PT) technique was applied to optimizing selective photothermolysis of cancer cells and bacteria into which nanoparticles have been incorporated (selective "nanophotothermolysis"). This technique involved first irradiating nanoparticles-penetrated cells with nanosecond pump-laser pulses in the visible spectral ranges. Laser-induced local thermal effects around the nanoparticles in the cancer cells or bacteria were then detected via time-resolved monitoring of temperature-dependent variations of the refractive index. This procedure was accomplished with imaging of a second probe-laser pulse. Analysis of the distinctive temporal shape of the PT response revealed linear and nonlinear phenomena around nanoparticles, such as alteration of local temperature, and bubble-formation-caused cell death accompanied by laser-induced melting and disintegration of particles. The damage threshold was obtained for live cancer cells in vitro depended on the size (range: 2-250 nm) and number of particles, laser energy, and number of pulses. Local heat-based induction of apoptosis and necrosis was controlled in parallel with conventional kits (e.g. trypan blue, Annexin V-propidium iodide) and optical and electron microscopy. The PT technique potentially allowed for the detection of nanoparticles that had been delivered into live cells by direct microinjection, natural diffusion, and selective targeting with antibodies.

  16. 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

  17. Functionalized mesoporous silica nanoparticles for oral delivery of budesonide

    SciTech Connect

    Yoncheva, K., E-mail: krassi.yoncheva@gmail.com [Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000 Sofia (Bulgaria); Popova, M. [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia (Bulgaria); Szegedi, A.; Mihaly, J. [Institute of Nanochemistry and Catalysis, Chemical Research Center, Hungarian Academy of Sciences, Pusztaszeri út. 59-67, 1025 Budapest (Hungary); Tzankov, B.; Lambov, N.; Konstantinov, S.; Tzankova, V. [Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000 Sofia (Bulgaria); Pessina, F.; Valoti, M. [Dipartimento di Scienze della Vita, Universita di Siena, via Aldo Moro 2, Siena (Italy)

    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.

  18. Mixed hemimicelles solid-phase extraction based on ionic liquid-coated Fe3O4/SiO2 nanoparticles for the determination of flavonoids in bio-matrix samples coupled with high performance liquid chromatography.

    PubMed

    He, Huan; Yuan, Danhua; Gao, Zhanqi; Xiao, Deli; He, Hua; Dai, Hao; Peng, Jun; Li, Nan

    2014-01-10

    A novel magnetic solid-phase extraction (MSPE) method based on mixed hemimicelles of room temperature ionic liquids (RTILs) coated Fe3O4/SiO2 nanoparticles (NPs) was developed for simultaneous extraction of trace amounts of flavonoids in bio-matrix samples. A comparative study on the use of RTILs (C16mimBr) and CTAB-coated Fe3O4/SiO2 NPs as sorbents was presented. Owing to bigger adsorption amounts for analytes, RTILs-coated Fe3O4/SiO2 NPs was selected as MSPE materials and three analytes luteolin, quercetin and kaempferol can be quantitatively extracted and simultaneously determined coupled with high performance liquid chromatography (HPLC) in urine samples. No interferences were caused by proteins or endogenous compounds. Good linearity (R(2)>0.9993) for all calibration curves was obtained, and the limits of detection (LOD) for luteolin, quercetin and kaempferol were 0.10 ng/mL, 0.50 ng/mL and 0.20 ng/mL in urine samples, respectively. Satisfactory recoveries (93.5-97.6%, 90.1-95.4% and 93.3-96.6% for luteolin, quercetin and kaempferol) in biological matrices were achieved. It was notable that while using a small amount of Fe3O4/SiO2 NPs (4.0 mg) and C16mimBr (1.0 mg), satisfactory preconcentration factors and extraction recoveries for the three flavonoids were obtained. To the best of our knowledge, this is the first time a mixed hemimicelles MSPE method based on RTILs and Fe3O4/SiO2 NPs magnetic separation has ever been used for pretreatment of complex biological samples. PMID:24290172

  19. CCMR: Bimetallic Nanoparticle Catalysis

    NSDL National Science Digital Library

    Chong, Hahn

    2010-08-15

    Bimetallic nanoparticles are of great interest in scientific research due to their large surface to volume ratios and surface restructuring that may occur during catalysis. Our goals were to synthesize different bimetallic nanoparticles and test their catalytic abilities for use in future experiments. The nanoparticles we concentrated on were Au/Ag alloy, Au/Cu alloy, and Au/Pd core-shell.

  20. 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

  1. Incorporating \\

    Microsoft Academic Search

    Robert E. McGrath; Anand Ranganathan; M. Dennis Mickunas; Roy H. Campbell

    The fundamental standards and protocols of a Ubiquitous Computing Sys- tem must define common interfaces and message formats. In addition to the common interfaces and message formats, the entities of the system must know or discover the \\

  2. Core-Shell Composite Nanoparticles: Synthesis, Characterization, and Applications

    NASA Astrophysics Data System (ADS)

    Sanyal, Sriya

    Nanoparticles are ubiquitous in various fields due to their unique properties not seen in similar bulk materials. Among them, core-shell composite nanoparticles are an important class of materials which are attractive for their applications in catalysis, sensing, electromagnetic shielding, drug delivery, and environmental remediation. This dissertation focuses on the study of core-shell type of nanoparticles where a polymer serves as the core and inorganic nanoparticles are the shell. This is an interesting class of supramolecular building blocks and can "exhibit unusual, possibly unique, properties which cannot be obtained simply by co-mixing polymer and inorganic particles". The one-step Pickering emulsion polymerization method was successfully developed and applied to synthesize polystyrene-silica core-shell composite particles. Possible mechanisms of the Pickering emulsion polymerization were also explored. The silica nanoparticles were thermodynamically favorable to self-assemble at liquid-liquid interfaces at the initial stage of polymerization and remained at the interface to finally form the shells of the composite particles. More importantly, Pickering emulsion polymerization was employed to synthesize polystyrene/poly(N-isopropylacrylamide) (PNIPAAm)-silica core-shell nanoparticles with N-isopropylacrylamide incorporated into the core as a co-monomer. The composite nanoparticles were temperature sensitive and could be up-taken by human prostate cancer cells and demonstrated effectiveness in drug delivery and cancer therapy. Similarly, by incorporating poly-2-(N,N)-dimethylamino)ethyl methacrylate (PDMA) into the core, pH sensitive core-shell composite nanoparticles were synthesized and applied as effective carriers to release a rheological modifier upon a pH change. Finally, the research focuses on facile approaches to engineer the transition of the temperature-sensitive particles and develop composite core-shell nanoparticles with a metallic shell.

  3. 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

  4. Polyol mediated synthesis of ZnO nanoparticles templated by bacterial cellulose.

    PubMed

    Chen, Shiyan; Zhou, Bihui; Hu, Weili; Zhang, Wen; Yin, Na; Wang, Huaping

    2013-02-15

    Zinc oxide nanoparticles have been successfully synthesized through a facile polyol method using bacterial cellulose (BC) as a template. BC membrane was used as a host matrix to introduce quantitatively Zn(2+) ions and then as nanoreactors to fabricate ZnO nanoparticles by hydrolysis of zinc acetate in a polyol medium. The influence of the concentration of zinc acetate and hydrolytic time on the morphologies and size of ZnO nanoparticles were investigated. The results indicated that the uniform spherical ZnO nanoparticles were incorporated into BC fibers. The resulting nanocomposites show good mechanical properties and high photocatalytic activity in the degradation of methyl orange. PMID:23399243

  5. 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.

  6. Characterization of starch films containing starch nanoparticles: part 1: physical and mechanical properties.

    PubMed

    Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

    2013-07-25

    We report, for the first time, the preparation method and characteristics of starch films incorporating spray dried and vacuum freeze dried starch nanoparticles. Physical properties of these films such as morphology, crystallinity, water vapor permeability (WVP), opacity, and glass transition temperature (Tg) and mechanical properties (strain versus temperature, strain versus stress, Young's modulus and toughness) were measured. Addition of both starch nanoparticles in starch films increased roughness of surface, lowered degree of crystallinity by 23.5%, WVP by 44% and Tg by 4.3°C, respectively compared to those of starch-only films. Drying method used in preparation of starch nanoparticles only affected opacity of films. The incorporation of nanoparticles in starch films resulted into denser films due to which the extent of variation of strain with temperature was much lower. The toughness and Young's modulus of films containing both types of starch nanoparticles were lower than those of control films especially at <100°C. PMID:23768605

  7. 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

  8. Incorporating externalities in conservation programs

    SciTech Connect

    Jordan, J.L. [Georgia Experiment Station, Griffin, GA (United States). Dept. of Agricultural and Applied Economics

    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.

  9. Effect of Nanoparticle Size on Nanoparticle Spatial Distribution in a Diblock Copolymer Supramolecular Thin Film

    NASA Astrophysics Data System (ADS)

    Bai, Peter; Kao, Joseph; Lucas, Matthew; Alivisatos, Paul; Xu, Ting

    2012-02-01

    The self-assembly of nanoparticles (NPs) opens many pathways towards generation of functional nanostructured materials with desirable optical, mechanical and electrical properties. A great challenge in this field is the effective control of NP spatial distribution within the block copolymer matrix, which is crucial in tailoring the macroscopic properties of the polymer/nanoparticle composites. We systematically investigated the effect of NP size on the spatial distribution of nanoparticles upon blending with a diblock copolymer based supramolecule in thin film. The spatial distribution of NPs in thin film was observed to be strongly dependent on NP size. These observations can be explained by the increase in entropic penalty of incorporating larger NPs associated with the deformation of the BCP block to accommodate the NPs. This effect is observed for NPs with different chemistries and could serve as a promising route to creating multifunctional thin film nanocomposites.

  10. INCORPORATING ANTHROPOGENIC PROCESSES IN SOIL CLASSIFICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter considers the need for incorporating anthropogenic processes in soil classification systems, describes fundamental approaches to soil classification and their underlying concepts that affect the incorporation of anthropogenic processes, and proposes possible approaches to incorporating ...

  11. Numerical study of carbonaceous nanoparticle formation behind shock waves

    Microsoft Academic Search

    J. Z. Wen; M. J. Thomson; M. F. Lightstone

    2006-01-01

    By incorporating complex chemical kinetics for both gaseous and particulate phases with a fixed sectional aerosol dynamics model, a detailed description of the properties of carbonaceous nanoparticles formed in the pyrolysis of carbon suboxide behind a reflected shock wave can be obtained. The model successfully predicted the induction time, growth rate and particle yield for the shock tube experiment. The

  12. Terminal supraparticle assemblies from similarly charged protein molecules and nanoparticles

    NASA Astrophysics Data System (ADS)

    Park, Jai Il; Nguyen, Trung Dac; de Queirós 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.

  13. 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

  14. De-alloyed platinum nanoparticles

    DOEpatents

    Strasser, Peter (Houston, TX); Koh, Shirlaine (Houston, TX); Mani, Prasanna (Houston, TX); Ratndeep, Srivastava (Houston, TX)

    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.

  15. 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…

  16. 48 Chemical Engineering Education Incorporating

    E-print Network

    Hesketh, Robert

    these to fields such as specialty chemical manufacture, green engineering, bio/pharmaceutical manufac- ture48 Chemical Engineering Education Incorporating GREEN ENGINEERING Into a Material and Energy prob- lems in chemical engineering. Problems of the type that can be used to motivate the student

  17. Incorporating Yoga Into College Counseling

    Microsoft Academic Search

    Christopher M. Adams; Ana Puig

    2008-01-01

    Yoga has become increasingly popular in the United States, and college counselors should be familiar with this practice due to its popularity among college students. This article provides a brief overview of yoga and research on its benefits for mental health concerns often experienced by college students. Additionally, it addresses methods of incorporating yoga into college counseling and offers a

  18. 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

  19. Monolithic cryopolymers with embedded nanoparticles. II. Capillary liquid chromatography of proteins using charged embedded nanoparticles.

    PubMed

    Arrua, R Dario; Haddad, Paul R; Hilder, Emily F

    2013-10-11

    The preparation of composite monolithic cryopolymers is presented. These novel porous materials were prepared in capillary format at -70°C using poly(ethyleneglycol) diacrylate (PEGDA) Mw 258 as the single monomer and a mixture of dioxane and water as the porogen. Positively (NR4(+)) or negatively (SO3(-)) charged nanoparticles were incorporated within the polymeric structure by direct addition of their suspensions to the polymerisation mixture. In contrast to our previous report using neutral nanoparticles, the trapping of charged nanoparticles is mostly observed at the polymer surface. The incorporation of these nanostructures improved the chromatographic separations of standard proteins under a hydrophobic interaction chromatography (HIC) separation mode. Moreover, the presence of ionic groups on the polymer surface allowed the application of these columns under ion-exchange (IEX) conditions. The results obtained in this work show that the functionalisation of monolithic columns by direct addition of nanoparticles is a good alternative towards the modification of monolithic polymers without altering the polymeric scaffold. PMID:24011507

  20. 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.

  1. Nanoparticle mediated micromotor motion

    NASA Astrophysics Data System (ADS)

    Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y.

    2015-03-01

    In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ~200 ?m s-1. By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ~10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems.In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ~200 ?m s-1. By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ~10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems. Electronic supplementary information (ESI) available: Fig. S1-S5 and Video S1-S3. See DOI: 10.1039/c4nr07558g

  2. A nanoparticle in plasma

    SciTech Connect

    Martynenko, Yu. V.; Nagel', M. Yu.; Orlov, M. A. [Russian Research Centre Kurchatov Institute (Russian Federation)

    2009-06-15

    Charge and energy fluxes onto a nanoparticle under conditions typical of laboratory plasmas are investigated theoretically. Here, by a nanoparticle is meant a grain the size of which is much smaller than both the electron Larmor radius and Debye length and the thermionic emission from which is not limited by the space charge. Under conditions at which thermionic emission plays an important role, the electric potential and temperature T{sub p} of a nanoparticle are determined by solving a self-consistent set of equations describing the balance of energy and charge fluxes onto the nanoparticle. It is shown that, when the degree of plasma ionization exceeds a critical level, the potential of the nanoparticle and the energy flux onto it increase with increasing nanoparticle temperature, so that, starting from a certain temperature, the nanoparticle potential becomes positive. The critical degree of ionization starting from which the potential of a nanoparticle is always positive is determined as a function of the plasma density and electron temperature. The nanoparticle temperature T{sub p} corresponding to the equilibrium state of a positively charged nanoparticle is found as a function of the electron density for different electron temperatures.

  3. Enhancement of luminescence of Rhodamine B by gold nanoparticles in thin films on glass for active optical materials applications

    Microsoft Academic Search

    Viktoria Levchenko; Michael Grouchko; Shlomo Magdassi; Tsiala Saraidarov; Renata Reisfeld

    Fluorescent dyes in solid matrices have many potential applications provided that their high optical efficiencies are achieved. We present here gold nanoparticles formed and incorporated together with fluorescent dye Rhodamine B into a film of polyvinyl alcohol (PVA). The increase of fluorescence of the dye results from its interaction with surface plasmons. The electric charge on the gold nanoparticles and

  4. Nanoparticles on Photovoltaic Performance of Fabricated DSSCs

    NASA Astrophysics Data System (ADS)

    Agarwala, Pooja; Makkar, Preeti; Sharma, Sarika; Garg, Rajnish

    2014-10-01

    The present work focuses on the synthesis of mixed phase TiO2 nanoparticles with reduced band gaps without even being doped. The synthesis was carried out by chemical route followed by heat treatments at different temperatures to favor rutile incorporation in anatase network. The significance of different heat treatment temperatures on the phase composition of TiO2 nanoparticles and its effect on optical band gap and the photovoltaic performance are analyzed. The thermal analysis, phases, morphology, and energy band gap of as-synthesized TiO2 nanoparticles have been characterized by DTA/TG, x-ray diffraction, field-emission scanning electron microscope, transmission electron microscope, and UV-Vis-NIR, respectively. The results show the presence of rutile (~15 nm) and anatase phases (~17 nm) in "as-synthesized" TiO2 nanoparticles. TiO2 nanoparticles are heat treated for 2 h at 200, 400, and 600 °C in air. It is observed that heat treatment results in higher photoactivity in visible region of the solar radiation and the material demonstrated high photovoltaic performance in conjunction with N-719. The optical band gap values are found to be in the range of 2.59-2.88 eV. The dye-sensitized solar cells (DSSCs) fabricated by TiO2 nanoparticles, heat treated at 600 ºC show the energy conversion efficiency (?) of 6.08% with high photo current density ( J sc) of 11.76 mA/cm2. The work highlighted in this paper represents the realization of simple method of achieving low band gap semiconductors without being doped, for DSSCs applications.

  5. 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

  6. 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

  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, Hückel, 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. 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

  9. 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.

  10. Page Contents: SPECTRUM DIGITAL INCORPORATED

    E-print Network

    Hero, Alfred O.

    : A SPECTRUM DIGITAL INCORPORATED 512842-0001 Wednesday, February 17, 2010 1 13 B TMS320C5515 EZDSP MODULE USED: SCHEMATIC CONTENTS 01 - TITLE PAGE 02 - TMS320C5515 GPIO/MMC/SPI/I2C 03 - TMS320C5515 CLK/JTAG/USB2 04 - TMS320C5515 EMIF 05 - TMS320C5515 POWER 06 - NOR FLASH 07 - CC BOARD INTERFACE 08 - MICRO SD

  11. Polymeric nanoparticles for molecular imaging.

    PubMed

    Srikar, R; Upendran, Anandhi; Kannan, Raghuraman

    2014-01-01

    Conventional imaging technologies (X-ray computed tomography, magnetic resonance, and optical) depend on contrast agents to visualize a target site or organ of interest. The imaging agents currently used in clinics for diagnosis suffer from disadvantages including poor target specificity and in vivo instability. Consequently, delivery of low concentrations of contrast agents to region of interest affects image quality. Therefore, it is important to selectively deliver high payload of contrast agent to obtain clinically useful images. Nanoparticles offer multifunctional capabilities to transport high concentrations of imaging probes selectively to diseased site inside the body. Polymeric nanoparticles, incorporated with contrast agents, have shown significant benefits in molecular imaging applications. These materials possess the ability to encapsulate different contrast agents within a single matrix enabling multimodal imaging possibilities. The materials can be surface conjugated to target-specific biomolecules for controlling the navigation under in vivo conditions. The versatility of this class of nanomaterials makes them an attractive platform for developing highly sensitive molecular imaging agents. The research community's progress in the area of synthesis of polymeric nanomaterials and their in vivo imaging applications has been noteworthy, but it is still in the pioneer stage of development. The challenges ahead should focus on the design and fabrication of these materials including burst release of contrasts agents, solubility, and stability issues of polymeric nanomaterials. PMID:24616442

  12. Comb Polymer Architectures for Versatile Nanoparticle Assembly

    NASA Astrophysics Data System (ADS)

    Mastroianni, Alexander; Thorkelsson, Kari; Zhao, Yue; Luther, Joseph; Millstone, Jill; Alivisatos, Paul; Frechet, Jean; Xu, Ting

    2009-03-01

    Nanoparticles are a material of interest in photovoltaic research due to their optical absorption properties. However, there have been many challenges for device fabrication. It has been difficult to produce continuous, homogenous films, and successes in this area have been highly dependent on the actual nanoparticles used, and have thus been hard to apply generally to different materials of interest. We show how this challenge can be overcome using a comb polymer architecture. Here, pentadecyl phenol small molecules are hydrogen bonded to polyvinyl pyridine. This alkyl moiety produced is compatible with the ligand shells of many nanomaterials. We incorporated these small molecules and nanoparticles into polystrene-polyvinyl pyridine block copolymers. This strategy was successful for assembling nanoparticles made out of a variety of materials, without special considerations for the actual core material or morphology. Following these successes in bulk samples we extended our studies to thin films of these composites. Here, the morphology is controlled by the interfacial interactions. These materials have the potential to be used for photovoltaic devices, as they are easily solution-processible. This strategy is generally applicable with the choice of small molecule mediating interactions with any desired nanomaterial.

  13. 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.

  14. Influence of ferrite nanoparticle type and content on the crystallization kinetics and electroactive phase nucleation of poly(vinylidene fluoride).

    PubMed

    Sencadas, Vitor; Martins, Pedro; Pitães, Alexandre; Benelmekki, Maria; Gómez Ribelles, José Luis; Lanceros-Mendez, Senentxu

    2011-06-01

    This work reports on the nucleation of the ?-phase of poly(vinylidene fluoride) (PVDF) by incorporating CoFe(2)O(4) and NiFe(2)O(4) nanoparticles, leading in this way to the preparation of magnetoelectric composites. The fraction of filler nanoparticles needed to produce the same ?- to ?-phase ratio in crystallized PVDF is 1 order of magnitude lower in the cobalt ferrite nanoparticles. The interaction between nanoparticles and PVDF chains induce the all-trans conformation in PVDF segments, and this structure then propagates in crystal growth. The nucleation kinetics is enhanced by the presence of nanoparticles, as corroborated by the increasing number of spherulites with increasing nanoparticle content and by the variations of the Avrami's exponent. Further, the decrease of the crystalline fraction of PVDF with increasing nanoparticle content indicates that an important fraction of polymer chains are confined in interphases with the filler particle. PMID:21545124

  15. Nanoparticles for Pulmonary Delivery

    Microsoft Academic Search

    Alan B. Watts; Robert O. Williams

    \\u000a This chapter aims to provide a rational for the use of nanoparticles in pulmonary delivery as well as an overview of strategies\\u000a and physiological implications of nanoparticle delivery to the lungs. Formulation aspects of nanoparticle systems in the form\\u000a of liquid dispersions and inhaled dry powders are also reviewed. The chapter also addresses the expanse of lung toxicology\\u000a research surrounding

  16. 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.

  17. 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

  18. 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

  19. Nanoparticle mediated micromotor motion.

    PubMed

    Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y

    2015-03-01

    In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ?200 ?m s(-1). By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ?10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems. PMID:25689965

  20. Fabrication of three-dimensionally interconnected nanoparticle superlattices and their lithium-ion storage properties.

    PubMed

    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

  1. Fabrication of three-dimensionally interconnected nanoparticle superlattices and their lithium-ion storage properties

    NASA Astrophysics Data System (ADS)

    Jiao, Yucong; Han, Dandan; Ding, Yi; Zhang, Xianfeng; Guo, Guannan; Hu, Jianhua; Yang, Dong; Dong, Angang

    2015-03-01

    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.

  2. 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

  3. 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

  4. Multifunctional Magnetic Nanoparticles for Medical Imaging Applications

    PubMed Central

    Fang, Chen; Zhang, Miqin

    2010-01-01

    Magnetic nanoparticles (MNPs) have attracted enormous research attention due to their unique magnetic properties that enable the detection by the non-invasive medical imaging modality—magnetic resonance imaging (MRI). By incorporating advanced features, such as specific targeting, multimodality, therapeutic delivery, the detectability and applicability of MNPs have been dramatically expanded. A delicate design on structure, composition and surface chemistry is essential to achieving desired properties in MNP systems, such as high imaging contrast and chemical stability, non-fouling surface, target specificity and/or multimodality. This article presents the design fundamentals on the development of MNP systems, from discussion of material selection for nanoparticle cores and coatings, strategies for chemical synthesis and surface modification and their merits and limitations, to conjugation of special biomolecules for intended functions, and reviews the recent advances in the field. PMID:20593005

  5. Uranium incorporation into amorphous silica.

    PubMed

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

    2014-08-01

    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 Å) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ? 3.1-3.2 Å, U at ? 3.8-3.9 Å). 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

  6. 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.

  7. Nanoparticles in drinking water

    Microsoft Academic Search

    Ralf Kaegi

    Synthetic nanoparticles are increasingly being used in everyday products, but little is known about environmental releases of these materials. Our knowledge of how many natural nanoparticles occur in drinking water is also inadequate. An initial assessment is presented here. Drinking water is clear, and yet it contains millions of particles. Substances are described as particulate - as opposed to dissolved

  8. Multifunctional, multicompartment polyorganosiloxane magnetic nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Utech, Stefanie; Scherer, Christian; Maskos, Michael

    2009-05-01

    We present the synthesis and characterization of maghemite nanoparticles (average size 6±1.5 nm) and their incorporation into the core of polyorganosiloxane core-shell nanospheres (total average diameter 35±10 nm). The nanoparticles are easily redispersable in organic solvents and can subsequently be modified by grafting of end-functionalized poly(ethylene oxide) to obtain water soluble nanospheres. The network structure of the nanospheres allows the diffusion of small molecules into the nanospheres, and consequently the nanospheres can be employed as nanocontainers and nanoreactors for potential biomedical applications.

  9. Tea-bag-like polymer nanoreactors filled with gold nanoparticles.

    PubMed

    Mitschang, Fabian; Schmalz, Holger; Agarwal, Seema; Greiner, Andreas

    2014-05-01

    Gold-containing polymer nanotubes, which showed both catalytic activity and resistance to leaching, were prepared by the "tubes by fiber templates" (TUFT) process. For this purpose, electrospun polymer nonwovens with incorporated poly(L-lactide)-stabilized gold nanoparticles were coated with poly(p-xylylene) by the chemical vapor deposition process, and then the inner fiber templates were removed. The resulting polymer tubes carried encapsulated gold nanoparticles which were shown to be immobilized and featured pronounced catalytic activity towards the hydrolytic oxidation of dimethylphenylsilane and the alcoholysis of dimethylphenylsilane with n-butanol. The macroscopic nonwovens could be used as tea-bag-like catalyst systems and showed excellent reusability. PMID:24700456

  10. Targeting intracellular compartments by magnetic polymeric nanoparticles.

    PubMed

    Kocbek, Petra; Kralj, Slavko; Kreft, Mateja Erdani; Kristl, Julijana

    2013-09-27

    Superparamagnetic iron oxide nanoparticles (SPIONs) show a great promise for a wide specter of bioapplications, due to their characteristic magnetic properties exhibited only in the presence of magnetic field. Their advantages in the fields of magnetic drug targeting and imaging are well established and their safety is assumed, since iron oxide nanoparticles have already been approved for in vivo application, however, according to many literature reports the bare metal oxide nanoparticles may cause toxic effects on treated cells. Therefore, it is reasonable to prevent the direct interactions between metal oxide core and surrounding environment. In the current research ricinoleic acid coated maghemite nanoparticles were successfully synthesized, characterized and incorporated in the polymeric matrix, resulting in nanosized magnetic polymeric particles. The carrier system was shown to exhibit superparamagnetic properties and was therefore responsive towards external magnetic field. Bioevaluation using T47-D breast cancer cells confirmed internalization of magnetic polymeric nanoparticles (MNPs) and their intracellular localization in various subcellular compartments, depending on presence/absence of external magnetic field. However, the number of internalized MNPs observed by fluorescent and transmission electron microscopy was relatively low, making such way of targeting effective only for delivery of highly potent drugs. The scanning electron microscopy of treated cells revealed that MNPs influenced the cell adhesion, when external magnetic field was applied, and that treatment resulted in damaged apical plasma membrane right after exposure to the magnetic carrier. On the other hand, MNPs showed only reversibly reduced cellular metabolic activity in concentrations up to 200 ?g/ml and, in the tested concentration the cell cycle distribution was within the normal range, indicating safety of the established magnetic carrier system for the treated cells. PMID:23603023

  11. Nanoparticle approaches against bacterial infections.

    PubMed

    Gao, Weiwei; Thamphiwatana, Soracha; Angsantikul, Pavimol; Zhang, Liangfang

    2014-01-01

    Despite the wide success of antibiotics, the treatment of bacterial infections 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 infections. 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

  12. 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.

  13. A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells

    NASA Astrophysics Data System (ADS)

    Freitas, Jilian N.; Gonçalves, 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.

  14. A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells.

    PubMed

    Freitas, Jilian N; Gonçalves, 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. 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.

  16. Transdermal delivery of mixnoxidil with block copolymer nanoparticles.

    PubMed

    Shim, Jongwon; Seok Kang, Hyung; Park, Won-Seok; Han, Sang-Hun; Kim, Junoh; Chang, Ih-Seop

    2004-07-01

    We evaluated the effect of hydrodynamic size of self-assembled nanoparticles on skin penetration of minoxidil in vitro and in vivo. Self-assembled 40- and 130-nm nanoparticles, both containing minoxidil, were prepared by solvent evaporation of poly(-caprolactone)-block-poly(ethyleneglycol) and were applied onto the skin of both hairy and hairless guinea pigs in the Franz diffusion cell. In hairy guinea pig skin, the permeation of the minoxidil that incorporated in 40-nm nanoparticles was 1.5-fold higher in the epidermal layer and 1.7-fold higher in the receptor solution than that of 130-nm nanoparticles. Nanoparticle size dependence on the permeation behavior of minoxidil was not observed for hairless guinea pig skin in either the epidermal layer or the receptor solution. Phospholipid liposomes and ethanol-water admixture, on the other hand, containing the same amount of minoxidil did not show differences in the amount of permeation irrespective of the existence of hair follicles. Confocal microscopy coupled with in vivo and in vitro skin permeation results demonstrated that nanoparticles containing solutes penetrated mainly via shunt routes like hair follicles, resulting in skin absorption of solutes. PMID:15212879

  17. HDL-Mimetic PLGA Nanoparticle To Target Atherosclerosis Plaque Macrophages.

    PubMed

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

    2015-03-18

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

  18. Magnetite-Alginate-AOT nanoparticles based drug delivery platform

    NASA Astrophysics Data System (ADS)

    Regmi, R.; Sudakar, C.; Dixit, A.; Naik, R.; Lawes, G.; Toti, U.; Panyam, J.; Vaishnava, P. P.

    2008-03-01

    Iron oxide having the magnetite structure is a widely used biomaterial, having applications ranging from cell separation and drug delivery to hyperthermia. In order to increase the efficacy of drug treatments, magnetite nanoparticles can be incorporated into a composite system with a surfactant-polymer nanoparticle, which can act as a platform for sustained and enhanced cellular delivery of water-soluble molecules. Here we report a composite formulation based on magnetite and Alginate-aerosol OT (AOT) nanoparticles formulated using an emulsion-cross-linking process loaded with Rhodamine 6G [1]. We prepared two set of nanoparticles by using Ca^2+ or Fe^2+ to cross-link the alginate polymer. Additionally, we added ˜8 nm diameter Fe3O4 magnetic nanoparticles prepared by a soft chemical method to these alginate-AOT nanoparticles. The resulting composites were superparamagnetic at room temperature, with a saturation magnetization of approximately 0.006 emu/g of solution. We will present detailed studies on the structural and magnetic properties of these samples. We will also discuss HPLC measurements on Rhodamine uploading in these composites. [1] M.D.Chavanpatil, Pharmaceutical Research, vol.24, (2007) 803.

  19. Synthesis, characterization and in vitro drug release of magnetic N-benzyl-O-carboxymethylchitosan nanoparticles loaded with indomethacin.

    PubMed

    Debrassi, Aline; Bürger, Cristiani; Rodrigues, Clóvis Antonio; Nedelko, Nataliya; ?lawska-Waniewska, Anna; D?u?ewski, Piotr; Sobczak, Kamil; Greneche, Jean-Marc

    2011-08-01

    Magnetic N-benzyl-O-carboxymethylchitosan nanoparticles were synthesized through incorporation and in situ methods and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and magnetization measurements. Indomethacin was incorporated into the nanoparticles via the solvent evaporation method. The indomethacin-loaded magnetic nanoparticles were characterized by the same techniques, and also by transmission electron microscopy. The nanoparticles containing the polymer showed a drug loading efficiency of between 60.8% and 74.8%, and the magnetic properties were not significantly affected by incorporation of the drug. The in vitro drug release study was carried out in simulated body fluid, pH 7.4 at 37°C. The profiles showed an initial fast release, which became slower as time progressed. The percentage of drug released after 5 h was between 60% and 90%, and the best fitting mathematical model for drug release was the Korsmeyer-Peppas model, indicating a Fickian diffusion mechanism. PMID:21601660

  20. MANUFACTURING ACCELERATING THE INCORPORATION OF MATERIALS

    E-print Network

    Magee, Joseph W.

    MANUFACTURING ACCELERATING THE INCORPORATION OF MATERIALS ADVANCES INTO MANUFACTURING PROCESSES NATIONAL NEED The proposed topic "Accelerating the Incorporation of Materials Advances into Manufacturing organizations, leading researchers from academic institutions, and others. Materials performance is often

  1. Targeted Nanoparticles Assembled via Complexation of Boronic Acid-Containing Targeting Moieties to Diol-Containing Polymers

    PubMed Central

    Han, Han; Davis, Mark E.

    2013-01-01

    The delivery of therapeutics via nanoscaled vehicles for solid cancer treatment can be enhanced by the incorporation of a targeting capability. Here, we describe a new method for assembling a targeted nanoparticle that utilizes the reversible covalent complexation between boronic acids and diols to achieve a targeted nanoparticle for the delivery of anti-cancer drug, camptothecin (CPT). CPT is conjugated to a biocompatible, hydrophilic copolymer of mucic acid and PEG (MAP). When this polymer-drug conjugate is placed in water, it self-assembles into MAP-CPT nanoparticles of ca. 30 nm (diameter) and slightly negative zeta potential. The antibody Herceptin is attached to a boronic acid via a polyethylene glycol (PEG) spacer, and this boronic acid-containing targeting moiety is complexed with the diol-containing MAP to form a targeted MAP-CPT nanoparticle. The addition of Herceptin targeting agent to the MAP-CPT nanoparticles yields targeted MAP-CPT nanoparticles with increased nanoparticle size to ca. 40 nm (diameter). The main mechanisms of CPT release from MAP-CPT nanoparticles are found by in vitro analysis to be hydrolysis and nanoparticle disruption by fat. Cellular uptake of nanoparticles is enhanced by 70% compared to non-targeted version by the incorporation of a single Herceptin antibody targeting agent per nanoparticle. This single Herceptin antibody targeted MAP-CPT nanoparticle system carries ca. 60 CPT molecules per nanoparticle and shows prolonged plasma circulation with an elimination half-life of 21.2 h and AUC value of 2766 ?g.h/ml at a 10 mg CPT/kg tail vein injection in mice. PMID:23461746

  2. Hydroxycamptothecin-loaded nanoparticles enhance target drug delivery and anticancer effect

    Microsoft Academic Search

    Anxun Wang; Su Li

    2008-01-01

    BACKGROUND: Hydroxycamptothecin (HCPT) has been shown to have activity against a broad spectrum of cancers. In order to enhance its tissue-specific delivery and anticancer activity, we prepared HCPT-loaded nanoparticles made from poly(ethylene glycol)-poly(?-benzyl-L-glutamate) (PEG-PBLG), and then studied their release characteristics, pharmacokinetic characteristics, and anticancer effects. PEG-PBLG nanoparticles incorporating HCPT were prepared by a dialysis method. Scanning electron microscopy (SEM) was

  3. Direct Electrochemistry of Cytochrome bo3 Oxidase at a series of Gold Nanoparticles-Modified Electrodes

    PubMed Central

    Melin, Frederic; Meyer, Thomas; Lankiang, Styven; Choi, Sylvia K.; Gennis, Robert B; Blanck, Christian; Schmutz, Marc; Hellwig, Petra

    2012-01-01

    New membrane-protein based electrodes were prepared incorporating cytochrome bo3 from E. coli and gold nanoparticles. Direct electron transfer between the electrode and the immobilized enzymes was achieved, resulting in an electrocatalytic activity in presence of O2. The size of the gold nanoparticles was shown to be important and smaller particles were shown to reduce the overpotential of the process. PMID:23335854

  4. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) in cosmetic and dermatological preparations

    Microsoft Academic Search

    R. H. Müller; M. Radtke; S. A. Wissing

    2002-01-01

    Solid lipid nanoparticles (SLN) were developed at the beginning of the 1990s as an alternative carrier system to emulsions, liposomes and polymeric nanoparticles. The paper reviews advantages—also potential limitations—of SLN for the use in topical cosmetic and pharmaceutical formulations. Features discussed include stabilisation of incorporated compounds, controlled release, occlusivity, film formation on skin including in vivo effects on the skin.

  5. 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…

  6. Ordered nanoparticle arrays interconnected by molecular linkers: electronic and optoelectronic properties.

    PubMed

    Liao, Jianhui; Blok, Sander; van der Molen, Sense Jan; Diefenbach, Sandra; Holleitner, Alexander W; Schönenberger, Christian; Vladyka, Anton; Calame, Michel

    2015-02-10

    Arrays of metal nanoparticles in an organic matrix have attracted a lot of interest due to their diverse electronic and optoelectronic properties. Recent work demonstrates that nanoparticle arrays can be utilized as a template structure to incorporate single molecules. In this arrangement, the nanoparticles act as electronic contacts to the molecules. By varying parameters such as the nanoparticle material, the matrix material, the nanoparticle size, and the interparticle distance, the electronic behavior of the nanoparticle arrays can be substantially tuned and controlled. Furthermore, via the excitation of surface plasmon polaritons, the nanoparticles can be optically excited and electronically read-out. The versatility and possible applications of well-ordered nanoparticle arrays has been demonstrated by the realization of switching devices triggered optically or chemically and by the demonstration of chemical and mechanical sensing. Interestingly, hexagonal nanoparticle arrays may also become a useful platform to study the physics of collective plasmon resonances that can be described as Dirac-like bosonic excitations. PMID:25367894

  7. Effect of magnetite nanoparticles on living rate of MCF-7 human breast cancer cells.

    PubMed

    Baba, Daisuke; Seiko, Yasuhiro; Nakanishi, Takuya; Zhang, Hong; Arakaki, Atsushi; Matsunaga, Tadashi; Osaka, Tetsuya

    2012-06-15

    Superparamagnetic and ferromagnetic magnetite nanoparticles, with diameters of approximately 13 and 44 nm, respectively, were synthesized and their uptake amount and heating efficiency were evaluated for application to magnetic hyperthermia. Both nanoparticles had almost the same zeta-potential (+10.2 mV) and hydrodynamic size (?1 ?m) and there was no significant difference in their uptake amount 18 h after they were added to the medium. After internalization, the ferromagnetic nanoparticles incorporated in human breast cancer cells (MCF-7) showed a higher heating efficiency than the superparamagnetic nanoparticles when an external magnetic field (4 kW, 250 kHz) high enough to produce heat by hysteresis loss was applied, followed by cellular death of MCF-7 with high ferromagnetic nanoparticle content. PMID:22486944

  8. Nanoparticle-Based Systems for T1-Weighted Magnetic Resonance Imaging Contrast Agents

    PubMed Central

    Zhu, Derong; Liu, Fuyao; Ma, Lina; Liu, Dianjun; Wang, Zhenxin

    2013-01-01

    Because magnetic resonance imaging (MRI) contrast agents play a vital role in diagnosing diseases, demand for new MRI contrast agents, with an enhanced sensitivity and advanced functionalities, is very high. During the past decade, various inorganic nanoparticles have been used as MRI contrast agents due to their unique properties, such as large surface area, easy surface functionalization, excellent contrasting effect, and other size-dependent properties. This review provides an overview of recent progress in the development of nanoparticle-based T1-weighted MRI contrast agents. The chemical synthesis of the nanoparticle-based contrast agents and their potential applications were discussed and summarized. In addition, the recent development in nanoparticle-based multimodal contrast agents including T1-weighted MRI/computed X-ray tomography (CT) and T1-weighted MRI/optical were also described, since nanoparticles may curtail the shortcomings of single mode contrast agents in diagnostic and clinical settings by synergistically incorporating functionality. PMID:23698781

  9. 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

  10. 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, UV–visible 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 Flynn–Wall–Ozawa 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

  11. Synthesis of Silver Nanoparticles

    NSDL National Science Digital Library

    Johnson, Chris

    This series of videos, presented by the Materials Research Science and Engineering Center at the University of Wisconsin-Madison, deals with the synthesis of silver nanoparticles. The experiment allows students to view the formation of silver nanoparticles that can be detected by the reflection of a laser beam. Silver nanoparticles are used in the creation of yellow stained glass in churches around the country, an interesting, but little known fact. This is a fairly inexpensive activity as it involves stock solutions, and equipment present in any science laboratory. Overall, students will enjoy this basic, but still challenging, experiment.

  12. Nanoparticle Stained Glass

    NSDL National Science Digital Library

    2014-06-18

    In this activity/demo, learners are introduced to the connection between medieval stained glass artisans and nanotechnology. Learners discover that the red and yellow colors in stained glass windows come from nanoparticles of gold and silver embedded in the glass. This activity/demo consists of two hands-on activities: making a collaborative stained glass window with pre-made nanoparticle solutions containing silver or gold and making a take-away card that contains a small piece of nanoparticle stained “glass."

  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. 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 ? /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

  15. Photoluminescence spectroscopy and lifetime measurements from self-assembled semiconductor-metal nanoparticle hybrid arrays.

    SciTech Connect

    Haridas, M.; Basue, J. K.; Gosztola, D. J.; Wiederrecht, G. P. (Center for Nanoscale Materials); (Indian Inst. of Science)

    2010-08-23

    We present results of photoluminescence spectroscopy and lifetime measurements on thin film hybrid arrays of semiconductor quantum dots and metal nanoparticles embedded in a block copolymer template. The intensity of emission as well as the measured lifetime would be controlled by varying the volume fraction and location of gold nanoparticles in the matrix. We demonstrate the ability to both enhance and quench the luminescence in the hybrids as compared to the quantum dot array films while simultaneously engineering large reduction in luminescence lifetime with incorporation of gold nanoparticles.

  16. New strategies for luminescence thermometry in the biological range using upconverting nanoparticles

    NASA Astrophysics Data System (ADS)

    Savchuk, Ol. A.; Carvajal, J. J.; Pujol, M. C.; Massons, J.; Haro-González, P.; Jaque, D.; Aguiló, M.; Díaz, F.

    2014-05-01

    We have studied different strategies of use of luminescence thermometry with upconverting nanoparticles in the biological range of temperatures, among them, the thermal sensing ability of fluoresncent lifetime of Er,Yb:NaY2F5 nanoparticles. Er,Yb:NaY2F5O nanocrystals show great potentiality as thermal sensors at the nanoscale for biomedical applications due to the incorporation of additional non-radiative relaxation mechanisms that shorten the emission lifetime generated by the oxygen present in the structure. Here we report ex-vivo temperature determination by laser induced heating in chicken breast using lifetime-based thermometry in these up-conversion nanoparticles.

  17. Shear thinning of nanoparticle suspensions

    NASA Astrophysics Data System (ADS)

    in 'T Veld, Pieter J.; Petersen, Matt K.; Grest, Gary S.

    2009-02-01

    Results of large scale nonequilibrium molecular dynamics simulations are presented for nanoparticles in an explicit solvent. The nanoparticles are modeled as a uniform distribution of Lennard-Jones particles, while the solvent is represented by standard Lennard-Jones particles. We present results for the shear rheology of spherical nanoparticles of diameter 10 times that of the solvent for a range of nanoparticle volume fractions. By varying the strength of the interactions between nanoparticles and with the solvent, this system can be used to model colloidal gels and glasses as well as hard spherelike nanoparticles. Effect of including the solvent explictly is demonstrated by comparing the pair correlation function of nanoparticles to that in an implicit solvent. The shear rheology for dumbbell nanoparticles made of two fused spheres is similar to that of single nanoparticle.

  18. 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.

  19. 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 15.8–43.3 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

  20. Ensemble learning incorporating uncertain registration.

    PubMed

    Simpson, Ivor J A; Woolrich, Mark W; Andersson, Jesper L R; Groves, Adrian R; Schnabel, Julia A

    2013-04-01

    This paper proposes a novel approach for improving the accuracy of statistical prediction methods in spatially normalized analysis. This is achieved by incorporating registration uncertainty into an ensemble learning scheme. A probabilistic registration method is used to estimate a distribution of probable mappings between subject and atlas space. This allows the estimation of the distribution of spatially normalized feature data, e.g., grey matter probability maps. From this distribution, samples are drawn for use as training examples. This allows the creation of multiple predictors, which are subsequently combined using an ensemble learning approach. Furthermore, extra testing samples can be generated to measure the uncertainty of prediction. This is applied to separating subjects with Alzheimer's disease from normal controls using a linear support vector machine on a region of interest in magnetic resonance images of the brain. We show that our proposed method leads to an improvement in discrimination using voxel-based morphometry and deformation tensor-based morphometry over bootstrap aggregating, a common ensemble learning framework. The proposed approach also generates more reasonable soft-classification predictions than bootstrap aggregating. We expect that this approach could be applied to other statistical prediction tasks where registration is important. PMID:23288332

  1. Effect of size distribution on metastability in magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yoh; Park, Kyungwha

    2011-03-01

    Magnetic nanoparticles that have been synthesized using various methods have size distributions. This results in distributions in the magnetic anisotropy of magnetic nanoparticles. Considering the particle size distributions, we investigate metastability in magnetic nanoparticles at low temperatures. To model this system, we use a spin S=1 ferromagnetic Blume-Capel model on a square lattice with periodic boundary conditions. The particle size distribution is incorporated in the model such that the uniaxial magnetic anisotropy parameter has a Gaussian distribution. We perform kinetic Monte Carlo simulations of the Blume-Capel model with the Glauber dynamic to explore magnetization relaxation in the regime where a single droplet of flipped spins forms a critical droplet. We present the lifetime of the metastable state as a function of temperature and standard deviation of the magnetic anisotropy distribution as well as a finite-size effect on the lifetime.

  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. 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

  4. Divalent metal nanoparticles

    E-print Network

    DeVries, Gretchen Anne

    2008-01-01

    Metal nanoparticles hold promise for many scientific and technological applications, such as chemical and biological sensors, vehicles for drug delivery, and subdiffraction limit waveguides. To fabricate such devices, a ...

  5. Thermally Polymerized Rylene Nanoparticles

    E-print Network

    Andrew, Trisha Lionel

    Rylene dyes functionalized with varying numbers of phenyl trifluorovinyl ether (TFVE) moieties were subjected to a thermal emulsion polymerization to yield shape-persistent, water-soluble chromophore nanoparticles. Perylene ...

  6. 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

  7. Magnetic nanoparticle temperature estimation.

    PubMed

    Weaver, John B; Rauwerdink, Adam M; Hansen, Eric W

    2009-05-01

    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 degree K between 20 and 50 degrees C using the current apparatus and half-second measurements. The method is independent of nanoparticle concentration and nanoparticle size distribution. PMID:19544801

  8. Magnetic nanoparticle temperature estimation

    PubMed Central

    Weaver, John B.; Rauwerdink, Adam M.; Hansen, Eric W.

    2009-01-01

    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 °K between 20 and 50?°C using the current apparatus and half-second measurements. The method is independent of nanoparticle concentration and nanoparticle size distribution. PMID:19544801

  9. Synthesis and characterization of photoswitchable fluorescent silica nanoparticles.

    PubMed

    Fölling, Jonas; Polyakova, Svetlana; Belov, Vladimir; van Blaaderen, Alfons; Bossi, Mariano L; Hell, Stefan W

    2008-01-01

    We have designed and synthesized a new functional (amino reactive) highly efficient fluorescent molecular switch (FMS) with a photochromic diarylethene and a rhodamine fluorescent dye. The reactive group in this FMS -N-hydroxysuccinimide ester- allows selective labeling of amino containing molecules or other materials. In ethanolic solutions, the compound displays a large fluorescent quantum yield of 52 % and a large fluorescence modulation ratio (94 %) between two states that may be interconverted with red and near-UV light. Silica nanoparticles incorporating the new FMS were prepared and characterized, and their spectroscopic and switching properties were also studied. The dye retained its properties after the incorporation into the silica, thereby allowing light-induced reversible high modulation of the fluorescence signal of a single particle for up to 60 cycles, before undergoing irreversible photobleaching. Some applications of these particles in fluorescence microscopy are also demonstrated. In particular, subdiffraction images of nanoparticles were obtained, in the focal plane of a confocal microscope. PMID:18064615

  10. 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

  11. 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

  12. Introduction to metallic nanoparticles.

    PubMed

    Mody, Vicky V; Siwale, Rodney; Singh, Ajay; Mody, Hardik R

    2010-10-01

    Metallic nanoparticles have fascinated scientist for over a century and are now heavily utilized in biomedical sciences and engineering. They are a focus of interest because of their huge potential in nanotechnology. Today these materials can be synthesized and modified with various chemical functional groups which allow them to be conjugated with antibodies, ligands, and drugs of interest and thus opening a wide range of potential applications in biotechnology, magnetic separation, and preconcentration of target analytes, targeted drug delivery, and vehicles for gene and drug delivery and more importantly diagnostic imaging. Moreover, various imaging modalities have been developed over the period of time such as MRI, CT, PET, ultrasound, SERS, and optical imaging as an aid to image various disease states. These imaging modalities differ in both techniques and instrumentation and more importantly require a contrast agent with unique physiochemical properties. This led to the invention of various nanoparticulated contrast agent such as magnetic nanoparticles (Fe(3)O(4)), gold, and silver nanoparticles for their application in these imaging modalities. In addition, to use various imaging techniques in tandem newer multifunctional nanoshells and nanocages have been developed. Thus in this review article, we aim to provide an introduction to magnetic nanoparticles (Fe(3)O(4)), gold nanoparticles, nanoshells and nanocages, and silver nanoparticles followed by their synthesis, physiochemical properties, and citing some recent applications in the diagnostic imaging and therapy of cancer. PMID:21180459

  13. Introduction to metallic nanoparticles

    PubMed Central

    Mody, Vicky V.; Siwale, Rodney; Singh, Ajay; Mody, Hardik R.

    2010-01-01

    Metallic nanoparticles have fascinated scientist for over a century and are now heavily utilized in biomedical sciences and engineering. They are a focus of interest because of their huge potential in nanotechnology. Today these materials can be synthesized and modified with various chemical functional groups which allow them to be conjugated with antibodies, ligands, and drugs of interest and thus opening a wide range of potential applications in biotechnology, magnetic separation, and preconcentration of target analytes, targeted drug delivery, and vehicles for gene and drug delivery and more importantly diagnostic imaging. Moreover, various imaging modalities have been developed over the period of time such as MRI, CT, PET, ultrasound, SERS, and optical imaging as an aid to image various disease states. These imaging modalities differ in both techniques and instrumentation and more importantly require a contrast agent with unique physiochemical properties. This led to the invention of various nanoparticulated contrast agent such as magnetic nanoparticles (Fe3O4), gold, and silver nanoparticles for their application in these imaging modalities. In addition, to use various imaging techniques in tandem newer multifunctional nanoshells and nanocages have been developed. Thus in this review article, we aim to provide an introduction to magnetic nanoparticles (Fe3O4), gold nanoparticles, nanoshells and nanocages, and silver nanoparticles followed by their synthesis, physiochemical properties, and citing some recent applications in the diagnostic imaging and therapy of cancer. PMID:21180459

  14. CCMR: Metal Nanoparticles Architectures for Nanoplasmonics Applications: Synthesis and Characterizations

    NSDL National Science Digital Library

    Livenere, John

    2009-08-15

    This summer my project was to increase the size of a nano particle called Cornell Dot or C. Dot. A C. Dot is a core-shell silica nanoparticles is the development of fluorescent particles based on organic dyes covalently incorporated into the silica matrix. Reactive dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the coreshell particle.

  15. OPTICAL PROPERTIES OFOPTICAL PROPERTIES OF METALLIC NANOPARTICLES,METALLIC NANOPARTICLES,

    E-print Network

    Grujicic, Mica

    OPTICAL PROPERTIES OFOPTICAL PROPERTIES OF METALLIC NANOPARTICLES,METALLIC NANOPARTICLES, MOLECULES,and Scattering of Light by Small Particles, Wiley: New York, 1983Wiley: New York, 1983.. #12;Extinction CrossDielectric Function of the Nanoparticles #12;Complex Dielectric FunctionComplex Dielectric Function For Bulk Material

  16. Nanoparticles for Targeted Drug Delivery

    E-print Network

    Chow, Gan-Moog

    Nanoparticles were synthesized and modified for target drug delivery. The research involved the aqueous synthesis of near infrared (NIR) sensitive Au-Au2S nanoparticles. An anti-cancer drug (cis-platin) ...

  17. 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.

  18. Automated Morphology Analysis of Nanoparticles

    E-print Network

    Park, Chiwoo

    2012-10-19

    The functional properties of nanoparticles highly depend on the surface morphology of the particles, so precise measurements of a particle's morphology enable reliable characterizing of the nanoparticle's properties. Obtaining the measurements...

  19. MICROBIAL IMPACTS OF ENGINEERED NANOPARTICLES

    EPA Science Inventory

    Reactivity at the nanometric scale is intimately linked to nanoparticle mobility and microbial sensitivity. Thus, first-order factors increasing nanoparticle reactivity should increase the rate of redox reactions with second-order effects on particle mobility and ecot...

  20. Harmonics based detection of magnetic nanoparticle dynamics for multiparameter biosensing

    NASA Astrophysics Data System (ADS)

    Rauwerdink, Adam M.

    Magnetic nanoparticles have an increasing role in the clinical and pharmaceutical realms where their physical properties can be exploited for imaging, biological and functional sensing, control of cellular processes, therapeutics, and an array of other applications. When excited by an alternating magnetic field, these particles will produce a series of harmonics. These harmonics have been exploited for in vitro particle detection and for in vivo imaging using magnetic particle imaging (MPI). Using a new technique, which we have termed magnetic spectroscopy of nanoparticle Brownian motion (MSB), we have shown how information about the physical environment of the particles can be extracted from this harmonic spectrum. A variety of physical effects have been detected and/or quantified including temperature, viscosity, nanoparticle binding, and aggregation. Further, we found these different environments to have a unique impact on the spectral signature of the nanoparticles which allows for simultaneous quantification of multiple environmental states. The thesis culminates with a study of MSB as a means for monitoring the cellular uptake of nanoparticles. Potential applications for MSB as a standalone technology and the potential for incorporation into MPI are discussed throughout.

  1. 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.

  2. Nano- and microstructures of magnetic field-guided maghemite nanoparticles in diblock copolymer films.

    PubMed

    Yao, Yuan; Metwalli, Ezzeldin; Niedermeier, Martin A; Opel, Matthias; Lin, Chen; Ning, Jing; Perlich, Jan; Roth, Stephan V; Müller-Buschbaum, Peter

    2014-04-01

    The control over the alignment of nanoparticles within a block copolymer matrix was investigated for different external magnetic fields with respect to producing well-aligned, highly oriented metal-oxide-polymer nanopatterns. Hybrid films were prepared by solution casting under a range of external magnetic fields. The nano- and microstructure of maghemite nanoparticles within poly(styrene-b-methyl methacrylate) diblock copolymer films as a function of the nanoparticle concentration was studied using optical microscopy, atomic force microscopy, scanning electron microscopy, and grazing incidence small-angle X-ray scattering. Because of a polystyrene (PS) coating, the nanoparticles are incorporated in the PS domains of the diblock copolymer morphology. At higher nanoparticle concentrations, nanoparticle aggregates perturb the block copolymer structure and accumulate at the films surface into wire-shaped stripes. These wire-shaped nanoparticle aggregates form mainly because of the competition between nanoparticle-polymer friction and magnetic dipolar interaction. The magnetic behavior of the hybrid films was probed at different temperatures for two orthogonal directions (with the line-shaped particle aggregates parallel and perpendicular to the magnetic field). The hybrid film systems show superparamagnetic behavior and remarkable shape anisotropy that render them interesting for magnetic applications. PMID:24621173

  3. Synthesis of Gold and Silver Nanoparticles Stabilized with Glycosaminoglycans having Distinctive Biological Activities

    PubMed Central

    Kemp, Melissa M.; Kumar, Ashavani; Mousa, Shaymaa; Park, Tae-Joon; Ajayan, Pulickel; Kubotera, Natsuki; Mousa, Shaker

    2009-01-01

    Metal nanoparticles have been studied for their anticoagulant and anti-inflammatory efficacy in various models. Specifically, gold and silver nanoparticles exhibit properties that make these ideal candidates for biological applications. The typical synthesis of gold and silver nanoparticles incorporates contaminants that could pose further problems. Here we demonstrate a clean method of synthesizing gold and silver nanoparticles that exhibit biological functions. These nanoparticles were prepared by reducing AuCl4 and AgNO3 using heparin and hyaluronan, as both reducing and stabilizing agents. The particles show stability under physiological conditions, and narrow size distributions for heparin particles and wider distribution for hyaluronan particles. Studies show that the heparin nanoparticles exhibit anticoagulant properties. Additionally, either gold- or silver- heparin nanoparticles exhibit local anti-inflammatory properties without any significant effect on systemic hemostasis upon administration in carrageenan-induced paw edema models. In conclusion, gold and silver nanoparticles complexed with heparin demonstrated effective anticoagulant and anti-inflammatory efficacy, having potential in various local applications. PMID:19226107

  4. Transport of NaYF4:Er3+, Yb3+ up-converting nanoparticles into HeLa cells

    NASA Astrophysics Data System (ADS)

    Sikora, Bo?ena; Fronc, Krzysztof; Kami?ska, Izabela; Koper, Kamil; Szewczyk, Sebastian; Paterczyk, Bohdan; Wojciechowski, Tomasz; Sobczak, Kamil; Minikayev, Roman; Paszkowicz, Wojciech; St?pie?, Piotr; Elbaum, Danek

    2013-06-01

    An effective, simple and practically useful method to incorporate fluorescent nanoparticles inside live biological cells was developed. The internalization time and concentration dependence of a frequently used liposomal transfection factor (Lipofectamine 2000) was studied. A user friendly, one-step technique to obtain water and organic solvent soluble Er3+ and Yb3+ doped NaYF4 nanoparticles coated with polyvinylpyrrolidone was obtained. Structural analysis of the nanoparticles confirmed the formation of nanocrystals of the desired sizes and spectral properties. The internalization of NaYF4 nanoparticles in HeLa cervical cancer cells was determined at different nanoparticle concentrations and for incubation periods from 3 to 24 h. The images revealed a redistribution of nanoparticles inside the cell, which increases with incubation time and concentration levels, and depends on the presence of the transfection factor. The study identifies, for the first time, factors responsible for an effective endocytosis of the up-converting nanoparticles to HeLa cells. Thus, the method could be applied to investigate a wide range of future ‘smart’ theranostic agents. Nanoparticles incorporated into the liposomes appear to be very promising fluorescent probes for imaging real-time cellular dynamics.

  5. Effects of aging on structure and stability of TiO2 nanoparticle-containing oil-in-water emulsions.

    PubMed

    Rossano, Manon; Hucher, Nicolas; Picard, Céline; Colletta, Daniel; Le Foll, Frank; Grisel, Michel

    2014-01-30

    Formulations incorporating different cosmetic grade TiO2 nanoparticles were developed according to a self-produced protocol on the basis of typical sunscreen cream oil-in-water emulsions. Role of nanoparticles and, more specifically, the impact of two different lipophilic surface treatments on microstructure and stability of the formulations were assessed. Aging of formulations was performed under classical conditions at room temperature or under accelerated conditions at 50 °C, with or without TiO2, and was characterized by several tools such as rheology, microscopy, and particle size measurements. Changes in emulsion stability and aggregation state of nanoparticles were followed over time. Destabilization phenomena were identified: under accelerated aging, the formulation without nanoparticles underwent a coalescence occurrence whereas the formulation incorporating nanoparticles was subjected to aggregation of the colloidal particles. Besides, TiO2 nanoparticles strongly affected the particle-droplets interactions and thus modified the emulsion microstructure with a coating-dependent effect: destabilization mechanisms occur more rapidly with alumina (and) triethoxycaprylylsilane (coating 1) TiO2 nanoparticles as compared to alumina (and) isopropyl titanium triisostearate (and) triethoxycaprylylsilane crosspolymer (coating 2) nanoparticles. PMID:24291079

  6. Molecularly-Targeted Gold-Based Nanoparticles for Cancer Imaging and Near-Infrared Photothermal Therapy

    NASA Astrophysics Data System (ADS)

    Day, Emily Shannon

    2011-12-01

    This thesis advances the use of nanoparticles as multifunctional agents for molecularly-targeted cancer imaging and photothermal therapy. Cancer mortality has remained relatively unchanged for several decades, indicating a significant need for improvements in care. Researchers are evaluating strategies incorporating nanoparticles as exogenous energy absorbers to deliver heat capable of inducing cell death selectively to tumors, sparing normal tissue. Molecular targeting of nanoparticles is predicted to improve photothermal therapy by enhancing tumor retention. This hypothesis is evaluated with two types of nanoparticles. The nanoparticles utilized, silica-gold nanoshells and gold-gold sulfide nanoparticles, can convert light energy into heat to damage cancerous cells. For in vivo applications nanoparticles are usually coated with poly(ethylene glycol) (PEG) to increase blood circulation time. Here, heterobifunctional PEG links nanoparticles to targeting agents (antibodies and growth factors) to provide cell-specific binding. This approach is evaluated through a series of experiments. In vitro, antibody-coated nanoparticles can bind breast carcinoma cells expressing the targeted receptor and act as contrast agents for multiphoton microscopy prior to inducing cell death via photoablation. Furthermore, antibody-coated nanoparticles can bind tissue ex vivo at levels corresponding to receptor expression, suggesting they should bind their target even in the complex biological milieu. This is evaluated by comparing the accumulation of antibody-coated and PEG-coated nanoparticles in subcutaneous glioma tumors in mice. Contrary to expectations, antibody targeting did not yield more nanoparticles within tumors. Nevertheless, these studies established the sensitivity of glioma to photothermal therapy; mice treated with PEG-coated nanoshells experienced 57% complete tumor regression versus no regression in control mice. Subsequent experiments employed intracranial tumors to better mimic the clinical setting. These tumors are highly vascularized, so nanoparticles were addressed toward receptors abundantly expressed on tumor vessels using growth factors as a novel targeting strategy. Photothermal therapy with these vascular-targeted nanoparticles disrupted tumor vessels, leading to a 2.2-fold prolongation of median survival versus control mice. This work confirms that nanoparticle surface coating can affect biodistribution and therapeutic efficacy. With continued optimization of molecular targeting strategies, imaging and photothermal therapy mediated by nanoshells and gold-gold sulfide nanoparticles may offer an effective alternative to conventional cancer management.

  7. Nanoparticle–polymer photovoltaic cells

    Microsoft Academic Search

    Brian R. Saunders; Michael L. Turner

    2008-01-01

    The need to develop and deploy large-scale, cost-effective, renewable energy is becoming increasingly important. In recent years photovoltaic (PV) cells based on nanoparticles blended with semiconducting polymers have achieved good power conversion efficiencies (PCE). All the nanoparticle types used in these PV cells can be considered as colloids. These include spherical, rod-like or branched organic or inorganic nanoparticles. Nanoparticle–polymer PV

  8. Synthesis of Multifunctional Nanoparticles for Cancer Diagnostics and Therapeutics

    NASA Astrophysics Data System (ADS)

    Fang, Chen

    2011-12-01

    Magnetic nanoparticles (MNPs) have attracted enormous research attention due to their unique magnetic properties that enable the detection by the non-invasive medical imaging modality---magnetic resonance imaging (MRI). By incorporating advanced features, such as specific targeting, multimodality, therapeutic delivery, the detectability and applicability of MNPs have been dramatically expanded. Smart and rational design on structure, composition and surface chemistry is essential to achieving desired properties in MNP systems, such as high sensitivity and colloidal stability, target specificity and/or multimodality. The goal of this research is to develop MNP-based platforms for the detection, diagnosis and treatment of cancer. MNPs with high contrast enhancement were coated with poly(ethylene glycol) (PEG)-based polymers to render aqueous stability and confer therapeutic-loading capability. Tumor-specific MNPs were developed by functionalization of nanoparticles with chlorotoxin (CTX) or arginine-glycine-aspartic acid (RGD) that targets, respectively, MMP-2 receptor or alphavbeta3 integrin overexpressed on a variety of cancer cells. The effects of ligands' molecular targets on the temporal and spatial distribution of MNPs within tumors were also investigated both in vitro and in vivo. All MNPs exhibited excellent long-term stability in cell culture media. CTX-labeled MNP exhibited sustained accumulation, penetration and distribution in the tumor mass. These findings revealed the influence of the targeting ligands on the intratumoral distribution of the ligand-enabled nanoprobes. To demonstrate the ability of nanoparticles as drug carrier, anthracyline chemotherapeutic drugs doxorubicin and mitoxantrone were attached to iron oxide nanoparticles. The theragnostic nanoparticles showed sufficient contrast enhancement and comparable anti-neoplastic efficacy in vitro. With flexible surface chemistry, our nanoparticle platform can be used in a modular fashion to conjugate biomolecules for intended applications, and the functionalized nanoparticle systems retain a prolonged stability and exhibit high tumor specificity. The study would establish the foundation for future development of integrated theragnostic systems for the treatment of cancer and other complex diseases.

  9. Development of Multifunctional Nanoparticles for Cancer Therapy Applications

    NASA Astrophysics Data System (ADS)

    Huth, Christopher

    The focus of this thesis is the functionalization and tailoring of nanoparticle surfaces to perform specific objectives in a biological environment. The nanoparticles examined include carbon nanotubes (CNTs), superparamagnetic iron oxide nanoparticles and superparamagnetic iron oxide nanocomposites. The unique nanomaterials have been developed to address continued issues in cancer therapy, including cancer diagnosis and efficient drug delivery. CNT surfaces were modified by plasma polymerization, providing functional groups for conjugation. Luminescent amine labeled quantum dots were fixed to the surface of the CNTs to aid in cancer diagnosis by in vivo imaging. Mice, injected with the quantum dot functionalized carbon nanotubes, were imaged displaying the in vivo imaging capability. In addition, the drug loading and drug release capabilities were examined by incorporating the drug paclitaxel into PLGA-coated CNTs, which showed much higher cytotoxicity to PC-3MM2 human prostate carcinoma cells compared to CNTs without paclitaxel. Paclitaxel was loaded at 112.5 microg/mg of PLGA-coated CNTs. Iron oxide nanocomposites were functionalized with quantum dots for diagnosis applications. Because the nanocomposites contain iron oxide, the nanoparticle provides the opportunity for magnetic hyperthermia, creating a unique material for diagnosis and therapy. Mice, injected with the quantum dot functionalized iron oxide nanocomposites, were imaged displaying the in vivo imaging capability. The magnetic hyperthermic property of the quantum dot functionalized nanocomposites was observed with the attainment of temperatures above 50°C during exposure to an alternating magnetic field. Thermoresponsive nanoparticles were prepared by immobilizing a 2 - 3 nm thick phospholipid layer on the surface of superparamagnetic Fe3O 4 nanoparticles via high affinity avidin/biotin interactions. Morphological and physicochemical surface properties were assessed using TEM, confocal laser scanning microscopy, differential scanning calorimetry, and ATR-FTIR. The zeta potential of Fe3O4 colloids in phosphate buffered saline (PBS) decreased from -23.6 to -5.0 mV as a consequence of phospholipid immobilization. Hyperthermia-relevant temperatures greater than 40°C were achieved within 10--15 min using a 7-mT magnetic field alternating at a frequency of 1MHz. Loading of the surface-associated phospholipid layer with the hydrophobic dye dansylcadaverine was accomplished at an efficiency of 479 ng/mg Fe3O4. Release of this drug surrogate was temperature-dependent, resulting in a 2.5-fold greater release rate when nanoparticles were exposed to temperatures above the experimentally determined melting temperature of 39.7°C. In vitro cytotoxicity studies by release of the cytotoxic drug, doxorubicin, from the thermoresponsive nanoparticles was lastly intended. However, colloidal stability became an issue, prompting a thorough review of nanoparticle stabilization. Factors affecting stabilization, including dispersant, the nanoparticle, and the thermoresponsive coating, were characterized by dynamic light scattering and zeta potential. PBS was compared to two dispersants containing lower ionic concentrations, HBSS and HEPES, using the original iron oxide nanoparticles compared to an iron oxide nanocomposite. The nanocomposite in the HEPES buffer displayed the greatest stability with a zeta potential of -30.47 mV and particle size of 155.4 nm. Stabilization of the immobilized phospholipid bilayer was examined with and without incorporation of the cationic lipid stearylamine. Zeta potential (33.6 mV) and size (315 nm) data indicate that stearylamine incorporated DPPC coated nanoparticles provide better stability.

  10. Novel light emissive yttrium-based nanoparticles and composites

    NASA Astrophysics Data System (ADS)

    Hill, Laura Burka

    Yttrium-based inorganic optical materials generally are of practical interest for three applications: solid state lighting/displays, lasers, and scintillators. Solid-state lighting is particularly desirable commercially for its efficiency and lifetime compared to traditional incandescent alternatives. This type of lighting technology is of increasing interest as incandescent light bulbs are being gradually phased-out due to government regulations on maximum wattage of these devices. Additionally, shortcomings in the current state of the art have driven the need for a more thermally stable material for use in this area. In this dissertation, we develop and characterize a novel composite material consisting of optically active yttrium-based nanoparticles doped into silica sol-gels. For lighting and display applications, low-cost, low-temperature synthesis methods for materials that meet or exceed the quality of the materials currently on the market are highly desirable. During the course of this work, we discuss the characterization of yttrium-based nanoparticles with respect to their incorporation in a sol-gel matrix composite. We then prepared these composite materials using a variety of methods and assess their quality according to a set of selection criteria and for lighting/display applications. Novel light-emitting composites consisting of Ce:YAG or Eu:Y2O 3 (yttria) nanoparticles in an inorganic medium were successfully developed and characterized. The optical properties of the nanoparticles were maintained when incorporated into the sol-gel medium and were shown to be comparable with the current state of the art. Comparison was made between the nanoparticle emission and the composite emission and, in the case of the Ce:YAG, the CIE coordinates, showing no change between the emission intensities or peak locations. We successfully demonstrated the conversion of fluoride-based particles into Y2O3 during sol-gel processing and demonstrated that no reaction took place between the nanoparticles and the sol-gel medium. Stability of nanoparticles in suspension was overcome through the control of pH during sol-gel synthesis. Through both base- and/or acid-catalysis, we produced optically active nanoparticle doped sol-gel composites containing YAG and Yttria. Our results indicated no detrimental effect on the nanoparticles upon incorporation into the sol-gel matrix; this was demonstrated through XRD, where no silicate phases were observed, through EDX, where we saw no diffusion of yttrium into the sol-gel and no silicon diffusing into the nanoparticles, and through photoluminescence, where emissions were consistent with that of the as-made nanoparticles. These results led us to theorize that the nanoparticles, rather than being bonded to the matrix, are seated in the void space that is prevalent in sol-gel systems. Additionally, these materials are stable at much higher temperatures than current resin-based systems.

  11. 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.

  12. Carbon nanoparticles from laser pyrolysis

    Microsoft Academic Search

    Aymeric Galvez; Nathalie Herlin-Boime; Cécile Reynaud; Christian Clinard; Jean-Noël Rouzaud

    2002-01-01

    Carbon nanoparticles synthesised by laser pyrolysis of hydrocarbons in a flow reactor have been investigated as a function of laser power. Samples are cross-characterised by high resolution transmission electron microscopy (HRTEM) and infrared (IR) spectroscopy. Nanoparticles appear highly aromatic in character in all the experimental conditions explored here. As the flame temperature in the interaction zone increases, the nanoparticles evolve

  13. Gold Nanoparticles Cytotoxicity

    NASA Astrophysics Data System (ADS)

    Mironava, Tatsiana

    Over the last two decades gold nanoparticles (AuNPs) have been used for many scientific applications and have attracted attention due to the specific chemical, electronic and optical size dependent properties that make them very promising agents in many fields such as medicine, imagine techniques and electronics. More specifically, biocompatible gold nanoparticles have a huge potential for use as the contrast augmentation agent in X-ray Computed Tomography and Photo Acoustic Tomography for early tumor diagnostic as well these nanoparticles are extensively researched for enhancing the targeted cancer treatment effectiveness such as photo-thermal and radiotherapy. In most biomedical applications biocompatible gold nanoparticles are labeled with specific tumor or other pathology targeting antibodies and used for site specific drug delivery. However, even though gold nanoparticles poses very high level of anti cancer properties, the question of their cytotoxicity ones they are released in normal tissue has to be researched. Moreover, the huge amount of industrially produced gold nanoparticles raises the question of these particles being a health hazard, since the penetration is fairly easy for the "nano" size substances. This study focuses on the effect of AuNPs on a human skin tissue, since it is fall in both categories -- the side effects for biomedical applications and industrial workers and users' exposure during production and handling. Therefore, in the present project, gold nanoparticles stabilized with the biocompatible agent citric acid were generated and characterized by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The cytotoxic effect of AuNPs release to healthy skin tissue was modeled on 3 different cell types: human keratinocytes, human dermal fibroblasts, and human adipose derived stromal (ADS) cells. The AuNPs localization inside the cell was found to be cell type dependent. Overall cytotoxicity was found to be dependent on time, concentration and nanoparticle size. Additionally, the question of cell recovery once the source of AuNPs is removed was investigated in the present work. It was found that full cell functions recovery is possible after removing the source of nanoparticles.

  14. Development of Microfluidic Devices Incorporating Electrochemical Detection

    E-print Network

    Regel, Anne

    2014-05-31

    Development of Microfluidic Devices Incorporating Electrochemical Detection Anne Regel Submitted to the Department of Chemistry and the Graduate School of the University of Kansas in partial fulfillment of the requirements for the degree... _______________________________ Karen Nordheden Dissertation Defense: August 21, 2013 ii The Dissertation Committee for Anne Regel certifies that this is the approved version of the following dissertation: Development of Microfluidic Devices Incorporating...

  15. 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…

  16. An Examination of Nova Scotia Power Incorporated's

    E-print Network

    Hughes, Larry

    1 An Examination of Nova Scotia Power Incorporated's Green Power Rider Larry Hughes Department of Electrical and Computer Engineering Dalhousie University Halifax, Nova Scotia, Canada, B3J 2X4 19 July 2002 This submission replaces the one of 17 July 2002. 1 Introduction In December 2001, Nova Scotia Power Incorporated

  17. Ribonucleotide incorporation by yeast DNA polymerase ?.

    PubMed

    Makarova, Alena V; Nick McElhinny, Stephanie A; Watts, Brian E; Kunkel, Thomas A; Burgers, Peter M

    2014-06-01

    During replication in yeast, the three B family DNA replicases frequently incorporate ribonucleotides (rNMPs) into DNA, and their presence in the nuclear genome can affect genome stability. This prompted us to examine ribonucleotide incorporation by the fourth B family member, Pol ?, the enzyme responsible for the majority of damage-induced mutagenesis in eukaryotes. We first show that Pol ? inserts rNMPs into DNA and can extend primer termini containing 3'-ribonucleotides. We then measure rNMP incorporation by Pol ? in the presence of its cofactors, RPA, RFC and PCNA and at normal cellular dNTP and rNTP concentrations that exist under unstressed conditions. Under these conditions, Pol ? stably incorporates one rNMP for every 200-300 dNMPs incorporated, a frequency that is slightly higher than for the high fidelity replicative DNA polymerases. Under damage-induced conditions wherein cellular dNTP concentrations are elevated 5-fold, Pol ? only incorporates one rNMP per 1300 dNMPs. Functional interaction of Pol ? with the mutasome assembly factor Rev1 gives comparable rNMP incorporation frequencies. These results suggest that ribonucleotide incorporation into DNA during Pol ?-mediated mutagenesis in vivo may be rare. PMID:24674899

  18. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Dummy 50th Percentile Male § 572.40 Incorporated materials...materials incorporated by reference are listed in the Finding Aids Table found at the end of this volume of the Code of Federal...

  19. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Dummy 50th Percentile Male § 572.40 Incorporated materials...materials incorporated by reference are listed in the Finding Aids Table found at the end of this volume of the Code of Federal...

  20. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Dummy 50th Percentile Male § 572.40 Incorporated materials...materials incorporated by reference are listed in the Finding Aids Table found at the end of this volume of the Code of Federal...

  1. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Dummy 50th Percentile Male § 572.40 Incorporated materials...materials incorporated by reference are listed in the Finding Aids Table found at the end of this volume of the Code of Federal...

  2. 49 CFR 572.40 - Incorporated materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Dummy 50th Percentile Male § 572.40 Incorporated materials...materials incorporated by reference are listed in the Finding Aids Table found at the end of this volume of the Code of Federal...

  3. Structural properties of rutile TiO2 nanoparticles accumulated in a model of gastrointestinal epithelium elucidated by micro-beam x-ray absorption fine structure spectroscopy

    NASA Astrophysics Data System (ADS)

    Veronesi, G.; Brun, E.; Fayard, B.; Cotte, M.; Carrière, M.

    2012-05-01

    Micro-beam x-ray absorption fine structure spectroscopy was used to investigate rutile TiO2 nanoparticles internalized into gastrointestinal cells during their crossing of a gut model barrier. Nanoparticles diluted in culture medium tend to accumulate in cells after 48 h exposure; however, no spectral differences arise between particles in cellular and in acellular environments, as corroborated by quantitative analysis. This finding establishes that no modification of the lattice properties of the nanoparticles occurs upon interaction with the barrier. These measurements demonstrate the possibility of interrogating nanoparticles in situ within cells, suggesting a way to investigate their fate when incorporated in biological hosts.

  4. Dual drug-loaded nanoparticles on self-integrated scaffold for controlled delivery

    PubMed Central

    Bennet, Devasier; Marimuthu, Mohana; Kim, Sanghyo; An, Jeongho

    2012-01-01

    Antioxidant (quercetin) and hypoglycemic (voglibose) drug-loaded poly-D,L-lactideco-glycolide nanoparticles were successfully synthesized using the solvent evaporation method. The dual drug-loaded nanoparticles were incorporated into a scaffold film using a solvent casting method, creating a controlled transdermal drug-delivery system. Key features of the film formulation were achieved utilizing several ratios of excipients, including polyvinyl alcohol, polyethylene glycol, hyaluronic acid, xylitol, and alginate. The scaffold film showed superior encapsulation capability and swelling properties, with various potential applications, eg, the treatment of diabetes-associated complications. Structural and light scattering characterization confirmed a spherical shape and a mean particle size distribution of 41.3 nm for nanoparticles in the scaffold film. Spectroscopy revealed a stable polymer structure before and after encapsulation. The thermoresponsive swelling properties of the film were evaluated according to temperature and pH. Scaffold films incorporating dual drug-loaded nanoparticles showed remarkably high thermoresponsivity, cell compatibility, and ex vivo drug-release behavior. In addition, the hybrid film formulation showed enhanced cell adhesion and proliferation. These dual drug-loaded nanoparticles incorporated into a scaffold film may be promising for development into a transdermal drug-delivery system. PMID:22888222

  5. Chitosan-lignosulfonates sono-chemically prepared nanoparticles: characterisation and potential applications.

    PubMed

    Kim, Suyeon; Fernandes, Margarida M; Matamá, Teresa; Loureiro, Ana; Gomes, Andreia C; Cavaco-Paulo, Artur

    2013-03-01

    Due to their recognised properties of biocompatibility, biodegradability and sustainability, chitosan nanocarriers have been successfully used as new delivery systems. In this work, nanoparticles combining chitosan and lignosulfonates were developed for the first time for cosmetic and biomedical applications. The ability of lignosulfonates to act as a counter polyion for stabilisation of chitosan particles, generated using high intensity ultrasound, was investigated. Several conditions for particles preparation were tested and optimised and the resulting nanoparticles were comprehensively characterised by measuring particle size, zeta potential and polydispersity index. The pH of chitosan solution, sonication time and the presence of an adequate surfactant, poloxamer 407, were determinant factors on the development of smaller particles with low polydispersity index (an average particle size of 230 nm was obtained at pH 5 after 8 min of sonication). The beneficial effects of lignosulfonates complex on chitosan nanoparticles were further characterised. Greater stability to lysozyme degradation, biocompatibility with human cells and antimicrobial activity was found upon lignosulfonates incorporation into chitosan nanoparticles. Furthermore, these particles were able to incorporate a hydrophilic model protein - RNase A. A burst release was observed when nanoparticles were loaded with low amount of protein while with high protein content, a sustained release was found, suggesting that the protein cargo maybe loaded both at the surface as in the bulk of the particle, depending on the concentration of drug incorporated. PMID:23178385

  6. Nanoparticle shuttle memory

    DOEpatents

    Zettl, Alex Karlwalter (Kensington, CA)

    2012-03-06

    A device for storing data using nanoparticle shuttle memory having a nanotube. The nanotube has a first end and a second end. A first electrode is electrically connected to the first end of the nanotube. A second electrode is electrically connected to the second end of the nanotube. The nanotube has an enclosed nanoparticle shuttle. A switched voltage source is electrically connected to the first electrode and the second electrode, whereby a voltage may be controllably applied across the nanotube. A resistance meter is also connected to the first electrode and the second electrode, whereby the electrical resistance across the nanotube can be determined.

  7. TOPICAL REVIEW: Biopolymeric nanoparticles

    NASA Astrophysics Data System (ADS)

    Sundar, Sushmitha; Kundu, Joydip; Kundu, Subhas C.

    2010-02-01

    This review on nanoparticles highlights the various biopolymers (proteins and polysaccharides) which have recently revolutionized the world of biocompatible and degradable natural biological materials. The methods of their fabrication, including emulsification, desolvation, coacervation and electrospray drying are described. The characterization of different parameters for a given nanoparticle, such as particle size, surface charge, morphology, stability, structure, cellular uptake, cytotoxicity, drug loading and drug release, is outlined together with the relevant measurement techniques. Applications in the fields of medicine and biotechnology are discussed along with a promising future scope.

  8. Nanoparticles from renewable polymers

    PubMed Central

    Wurm, Frederik R.; Weiss, Clemens K.

    2014-01-01

    The use of polymers from natural resources can bring many benefits for novel polymeric nanoparticle systems. Such polymers have a variety of beneficial properties such as biodegradability and biocompatibility, they are readily available on large scale and at low cost. As the amount of fossil fuels decrease, their application becomes more interesting even if characterization is in many cases more challenging due to structural complexity, either by broad distribution of their molecular weights (polysaccharides, polyesters, lignin) or by complex structure (proteins, lignin). This review summarizes different sources and methods for the preparation of biopolymer-based nanoparticle systems for various applications. PMID:25101259

  9. Thermally stable nanoparticles on supports

    DOEpatents

    Roldan Cuenya, Beatriz; Naitabdi, Ahmed R.; Behafarid, Farzad

    2012-11-13

    An inverse micelle-based method for forming nanoparticles on supports includes dissolving a polymeric material in a solvent to provide a micelle solution. A nanoparticle source is dissolved in the micelle solution. A plurality of micelles having a nanoparticle in their core and an outer polymeric coating layer are formed in the micelle solution. The micelles are applied to a support. The polymeric coating layer is then removed from the micelles to expose the nanoparticles. A supported catalyst includes a nanocrystalline powder, thin film, or single crystal support. Metal nanoparticles having a median size from 0.5 nm to 25 nm, a size distribution having a standard deviation .ltoreq.0.1 of their median size are on or embedded in the support. The plurality of metal nanoparticles are dispersed and in a periodic arrangement. The metal nanoparticles maintain their periodic arrangement and size distribution following heat treatments of at least 1,000.degree. C.

  10. Effect of the crystallinity of silver nanoparticles on surface plasmon resonance induced enhancement of effective absorption cross-section of dyes

    NASA Astrophysics Data System (ADS)

    Tanvi, Mahajan, Aman; Bedi, R. K.; Kumar, Subodh; Saxena, Vibha; Aswal, D. K.

    2015-02-01

    The effective absorption cross-section of dye, and therefore, the efficiency of dye-sensitized solar cell can be increased by surface plasmon resonance (SPR) of metal nanoparticles with enhanced dephasing time. Further, the dephasing time is proportional to the enhancement factor of electric field in the vicinity of nanoparticle surface, and is governed by size, shape, and dielectric constant of surrounding medium. In this paper, we demonstrate that crystallinity of silver nanoparticles plays an important role in enhancing the dephasing time of SPR. Our theoretical formulation indicates that the dephasing time is higher for single crystalline silver nanoparticles as compared to that of polycrystalline nanoparticles, which is attributed to the presence of scattering centers in the latter. This suggests that single crystalline silver nanoparticles are interesting candidates for the enhancement of effective absorption cross-section of dyes. In order to validate our theoretical formulation, we have synthesized single crystalline and polycrystalline silver nanoparticles and studied their effect on absorption cross-section of N719 dye. We observed that dye incorporated with single crystalline silver nanoparticles showed a significant enhancement as compared to polycrystalline silver nanoparticles (24.42% in solution, 21.01% in thin film form in single crystalline silver nanoparticles while 8.52% in solution, 7.97% in thin film form in polycrystalline silver nanoparticles, respectively).

  11. P-modified and carbon shell coated Co nanoparticles for efficient alkaline oxygen reduction catalysis.

    PubMed

    Ryu, Jaeyune; Jung, Namgee; Lim, Dong-Hee; Shin, Dong Yun; Park, Sae Hume; Ham, Hyung Chul; Jang, Jong Hyun; Kim, Hyoung-Juhn; Yoo, Sung Jong

    2014-12-28

    Described herein is the development of a novel Co-based oxygen electrode catalyst coupled with unique carbon structures. The present carbon shell coated Co nanoparticles of which the surface composites are modified by phosphorus incorporation, exhibit efficient oxygen reduction activities as well as oxygen evolving properties. PMID:25382192

  12. Biodegradable Nanoparticles With Sustained Release of Functional siRNA in Skin

    E-print Network

    Zare, Richard N.

    polymer poly(L-lactic acid) (L-PLA) was used together with a copolymer of L-PLA-poly(ethylene glycol) (PEG to incorporate siRNA in biodegradable polymer nanoparticles (NPs) for in vivo sustained release. By this means we, which demonstrates that the siRNA retained activity following release from the polymer NPs. ß 2010 Wiley

  13. Phase I clinical trial and pharmacokinetic evaluation of doxorubicin carried by polyisohexylcyanoacrylate nanoparticles

    Microsoft Academic Search

    Joseph Kattan; Jean-Pierre Droz; Patrick Couvreur; Jean-Pierre Marino; Arnaud Boutan-Laroze; Philippe Rougier; Philippe Brault; Henri Vranckx; Jean-Marc Grognet; Xavier Morge; Hélène Sancho-Garnier

    1992-01-01

    Doxorubicin (DXR) incorporated into biodegradable acrylate nanoparticles such as polyisohexylcyanoacrylate (PIHCA) has been shown to increase DXR cytotoxicity and reduce cardiotoxicity by modifying tissue distribution in preclinical studies. We have conducted a phase I clinical trial of DXR-PIHCA in 21 patients with refractory solid tumors (10 male, 11 female, median age: 53 years, median PS: 1, prior free-DXR therapy: 7

  14. Photochemical synthesis of biocompatible and antibacterial silver nanoparticles embedded within polyurethane polymers.

    PubMed

    Saez, Sara; Fasciani, Chiara; Stamplecoskie, Kevin G; Gagnon, Luke Brian-Patrick; Mah, Thien-Fah; Marin, M Luisa; Alarcon, Emilio I; Scaiano, Juan C

    2015-04-01

    In situ light initiated synthesis of silver nanoparticles (AgNP) was employed for AgNP incorporation within the polymeric matrices of medical grade polyurethane. The resulting materials showed improved antibacterial and antibiofilm activity against Pseudomonas aeruginosa with negligible toxicity for human primary skin cells and erythrocytes. PMID:25662069

  15. Molecular dynamics study of nanoparticles and non-ionic surfactant at an oil water interface

    E-print Network

    Nielsen, Steven O.

    Molecular dynamics study of nanoparticles and non-ionic surfactant at an oil­ water interface R. J) and surfactants can spontaneously concentrate at the interface between two immiscible liquids, such as oil and consumer products. Although NPs and surfactants are currently incorporated into many of these applications

  16. Enhancement of perovskite-based solar cells employing core-shell metal nanoparticles.

    PubMed

    Zhang, Wei; Saliba, Michael; Stranks, Samuel D; Sun, Yao; Shi, Xian; Wiesner, Ulrich; Snaith, Henry J

    2013-09-11

    Recently, inorganic and hybrid light absorbers such as quantum dots and organometal halide perovskites have been studied and applied in fabricating thin-film photovoltaic devices because of their low-cost and potential for high efficiency. Further boosting the performance of solution processed thin-film solar cells without detrimentally increasing the complexity of the device architecture is critically important for commercialization. Here, we demonstrate photocurrent and efficiency enhancement in meso-superstructured organometal halide perovskite solar cells incorporating core-shell Au@SiO2 nanoparticles (NPs) delivering a device efficiency of up to 11.4%. We attribute the origin of enhanced photocurrent to a previously unobserved and unexpected mechanism of reduced exciton binding energy with the incorporation of the metal nanoparticles, rather than enhanced light absorption. Our findings represent a new aspect and lever for the application of metal nanoparticles in photovoltaics and could lead to facile tuning of exciton binding energies in perovskite semiconductors. PMID:23947387

  17. Enhancement of the fluorescence of triphenylmethane dyes caused by their interaction with nanoparticles from ?-diketonate complexes

    NASA Astrophysics Data System (ADS)

    Sveshnikova, E. B.; Ermolaev, V. L.

    2014-08-01

    We have studied the absorption and fluorescence spectra of Malachite Green and Crystal Violet in aqueous and alcoholic-aqueous solutions in which nanoparticles from Ln(III) and Sc(III) diketonates are formed at concentrations of complexes in a solution of 5-30 ?M. We have shown that, if the concentrations of the dyes in the solution are lower than 0.5 ?M, dye molecules are incorporated completely into nanoparticles or are precipitated onto their surface. The fluorescence intensity of these incorporated and adsorbed Malachite Green and Crystal Violet molecules increases by several orders of magnitude compared to the solution, which takes place because of a sharp increase in the fluorescence quantum yields of these dyes and at the expense of the sensitization of their fluorescence upon energy transfer from ?-diketonate complexes entering into the composition of nanoparticles. We have shown that, if there is no concentration quenching, the values of the fluorescence quantum yield of the Crystal Violet dye incorporated into nanoparticles and adsorbed on their surface vary from 0.06 to 0.13, i.e., are close to the fluorescence quantum yield of this dye in solid solutions of sucrose acetate at room temperature. The independence of the fluorescence quantum yield of Crystal Violet on the morphology of nanoparticles testifies to a high binding constant of complexes and the dye. The considerable fluorescence quantum yields of triphenylmethane dyes in nanoparticles and sensitization of their fluorescence by nanoparticle-forming complexes make it possible to determine the concentration of these dyes in aqueous solutions by the luminescent method in the range of up to 1 nM.

  18. Magnetite nanoparticle-loaded anti-HER2 immunoliposomes for combination of antibody therapy with hyperthermia.

    PubMed

    Ito, Akira; Kuga, Yuko; Honda, Hiroyuki; Kikkawa, Hiroyuki; Horiuchi, Atsushi; Watanabe, Yuji; Kobayashi, Takeshi

    2004-08-30

    Anti-HER2 antibody can induce antitumor responses, and can be used in delivering drugs to HER2-overexpressing cancer. Previously, we produced hyperthermia using magnetite nanoparticles that generate heat in an alternating magnetic field. In the present study, we constructed anti-HER2 immunoliposomes containing magnetite nanoparticles, which act as tumor-targeting vehicles, combining anti-HER2 antibody therapy with hyperthermia. The magnetite nanoparticle-loaded anti-HER2 immunoliposomes exerted HER2-mediated antiproliferative effects on SKBr3 breast cancer cells in vitro. Moreover, 60% of magnetite nanoparticles were incorporated into SKBr3, and the cells were then heated at 42.5 degrees C under an alternating magnetic field, resulting in strong cytotoxic effects. These results suggest that this novel therapeutic tool is applicable to treatment of HER2-overexpressing cancer. PMID:15279897

  19. Photosensitizer-conjugated magnetic nanoparticles for in vivo simultaneous magnetofluorescent imaging and targeting therapy.

    PubMed

    Huang, Peng; Li, Zhiming; Lin, Jing; Yang, Dapeng; Gao, Guo; Xu, Cheng; Bao, Le; Zhang, Chunlei; Wang, Kan; Song, Hua; Hu, Hengyao; Cui, Daxiang

    2011-05-01

    A major challenge in nanotechnology and nanomedicine is to integrate tumor targeting, imaging, and selective therapy functions into a small single nanoparticle (<50 nm). Herein, photosensitizer-conjugated magnetic nanoparticles with ?20 nm in diameter were strategically designed and prepared for gastric cancer imaging and therapy. The second generation photosensitizer chlorin e6 (Ce6) was covalently anchored on the surface of magnetic nanoparticles with silane coupling agent. We found that the covalently incorporated Ce6 molecules retained their spectroscopic and functional properties for near-infrared (NIR) fluorescence imaging and photodynamic therapy (PDT), and the core magnetic nanoparticles offered the functions of magnetically guided drug delivery and magnetic resonance imaging (MRI). The as-prepared single particle platform is suitable for simultaneous targeting PDT and in vivo dual-mode NIR fluorescence imaging and MRI of nude mice loaded with gastric cancer or other tumors. PMID:21303717

  20. A New Class of Silica Crosslinked Micellar Core-Shell /nanoparticles."

    SciTech Connect

    Huo, Qisheng; Liu, Jun; Wang, Li Q.; Jiang, Yingbing; Lambert, Timothy N.; Fang, Erica

    2006-05-17

    Micellar nanoparticles made of surfactants and polymers have attracted wide attention in the materials and biomedical community for controlled drug delivery, molecular imaging and sensing; however, their long-term stability remains a topic of intense study. Here we report a new class of robust, ultrafine (10nm) silica core-shell nanoparticles formed from silica crosslinked, individual block copolymer micelles. Compared with pure polymer micelles, the new core-shell nanoparticles have significantly improved stability and do not break down during dilution. They also achieve much higher loading capacity for a wide range of chemicals, with the entrapped molecules slowly released over a much longer period of time. A wide range of functional groups can be easily incorporated through co-condensation with the silica matrix. The potential to deliver hydrophobic agents into cancer cells has been demonstrated. Because of their unique properties, these novel core-shell nanoparticles could potentially provide a new nanomedicine platform for imaging, detection and treatment.

  1. Photophysical properties and biocompatibility of Photoluminescent Y2O3:Eu nanoparticles in polymethylmetacrylate matrix.

    PubMed

    Abe, Shigeaki; Hamba, Yusuke; Iwadera, Nobuki; Yamagata, Shuichi; Yawaka, Yasutaka; Uo, Motohiro; Iida, Junichiro; Kiba, Takayuki; Murayama, Akihiro; Watari, Fumio

    2014-04-01

    In this study, we produced europium-doped yttoria (Y2O3:Eu) nanoparticles and investigated their photoluminescent properties and biocompatibility. The Y2O3:Eu nanoparticles showed excellent photoluminescent properties and cytocompatibility. We also analyzed the photophysical properties of the nanoparticles in PMMA films. When the Y2O3:Eu nanoparticles were incorporated in the polymer film, they showed a strong red emission spectrum, similar to that seen with the particles alone. Energy dispersive X-ray spectroscopy (EDS) measurements indicated that the particles were distributed homogeneously in the PMMA film. Such materials could be applied not only to optoelectronic devices but also to biomedical applications such as bioimaging tools or luminescent medical/dental adhesive materials. PMID:24734706

  2. Synthesis and characterization of tat-mediated O-CMC magnetic nanoparticles having anticancer function

    NASA Astrophysics Data System (ADS)

    Zhao, Aijie; Yao, Peng; Kang, Chunshang; Yuan, Xubo; Chang, Jin; Pu, Peiyu

    2005-08-01

    This paper describes a new formulation of magnetic nanoparticles coated by a novel polymer matrix—O-carboxylmethylated chitosan (O-CMC) as drug/gene carrier. The O-CMC magnetic nanoparticles were derivatized with a peptide sequence from the HIV-tat protein to improve the translocational property and cellar uptake of the nanoparticles. To evaluate the O-MNPs-tat as drug carriers, MTX was incorporated as a model drug and MTX-loaded O-MNPs-tat with an average diameter of 45-60 nm were prepared and characterized by TEM, AFM and VSM. The cytotoxicity of MTX-loaded O-MNPs-tat was investigated with U-937 tumor cells. The results showed that the MTX-loaded O-MNPs-tat retained significant antitumor toxicity; additionally, sustained release of MTX from O-CMC nanoparticles was observed in vitro, suggesting that the tat-O-MNPs could be a novel magnetic targeting carrier.

  3. Self-assembled nanoparticles of acetylated cashew gum: characterization and evaluation as potential drug carrier.

    PubMed

    Pitombeira, Nadia A O; Veras Neto, José Guilherme; Silva, Durcilene A; Feitosa, Judith P A; Paula, Haroldo C B; de Paula, Regina C M

    2015-03-01

    Acetylated cashew gum (ACG) was synthesized and self-assembled nanoparticles were obtained through the dialysis of an organic solution (DMSO) against a non-solvent (water). The ACG was characterized by infrared spectroscopy. The degree of substitution was 2.8 as determined by NMR spectroscopy. The physicochemical properties of the self-assembled nanoparticles in aqueous media were characterized by DLS, SEM and fluorescence spectroscopy. The mean diameter of the self-assembled nanoparticles obtained was 179 nm and the critical aggregation concentration (CAC) in water was 2.1×10(-3) g/L. Indomethacin (IND) was used as a hydrophobic model drug and was incorporated into the hydrophobized polysaccharide. Both loaded and unloaded nanoparticles were found to be spherical with diameters in the ranges of 70-170 nm and 108-314 nm (determined by SEM), respectively. Controlled drug release was observed for up to 72 h. PMID:25498678

  4. Study of magnetic nanoparticles and overcoatings for biological applications including a sensor device

    NASA Astrophysics Data System (ADS)

    Grancharov, Stephanie G.

    I. A general introduction to the field of nanomaterials is presented, highlighting their special attributes and characteristics. Nanoparticles in general are discussed with respect to their structure, form and properties. Magnetic particles in particular are highlighted, especially the iron oxides. The importance and interest of integrating these materials with biological media is discussed, with emphasis on transferring particles from one medium to another, and subsequent modification of surfaces with different types of materials. II. A general route to making magnetic iron oxide nanoparticles is explained, both as maghemite and magnetite, including properties of the particles and characterization. A novel method of producing magnetite particles without a ligand is then presented, with subsequent characterization and properties described. III. Attempts to coat iron oxide nanoparticles with a view to creating biofunctional magnetic nanoparticles are presented, using a gold overcoating method. Methods of synthesis and characterization are examined, with unique problems to core-shell structures analyzed. IV. Solubility of nanoparticles in both aqueous and organic media is discussed and examined. The subsequent functionalization of the surface of maghemite and magnetite nanoparticles with a variety of biomaterials including block copolypeptides, phospholipids and carboxydextran is then presented. These methods are integral to the use of magnetic nanoparticles in biological applications, and therefore their properties are examined once tailored with these molecules. V. A new type of magnetic nanoparticle sensor-type device is described. This device integrates bio-and DNA-functionalized nanoparticles with conjugate functionalized silicon dioxide surfaces. These techniques to pattern particles to a surface are then incorporated into a device with a magnetic tunnel junction, which measures magnetoresistance in the presence of an external magnetic field. This configuration thereby introduces a new way to detect magnetic nanoparticles via their magnetic properties after conjugation via biological entities.

  5. Noninvasive Fluorescence Resonance Energy Transfer Imaging of in vivo Premature Drug Release from Polymeric Nanoparticles

    PubMed Central

    Zou, Peng; Chen, Hongwei; Paholak, Hayley J.; Sun, Duxin

    2013-01-01

    Understanding in vivo drug release kinetics is critical for the development of nanoparticle-based delivery systems. In this study, we developed a fluorescence resonance energy transfer (FRET) imaging approach to noninvasively monitor in vitro and in vivo cargo release from polymeric nanoparticles. The FRET donor dye (DiO or DiD) and acceptor dye (DiI or DiR) were individually encapsulated into poly(ethylene oxide)-b-polystyrene (PEO-PS) nanoparticles. When DiO (donor) nanoparticles and DiI (acceptor) nanoparticles were co-incubated with cancer cells for 2 h, increased FRET signals were observed from cell membranes, suggesting rapid release of DiO and DiI to cell membranes. Similarly, increased FRET ratios were detected in nude mice after intravenous co-administration of DiD (donor) nanoparticles and DiR (acceptor) nanoparticles. In contrast, another group of nude mice i.v. administrated with DiD/DiR co-loaded nanoparticles showed decreased FRET ratios. Based on the difference in FRET ratios between the two groups, in vivo DiD/DiR release half-life from PEO-PS nanoparticles was determined to be 9.2 min. In addition, it was observed that the presence of cell membranes facilitated burst release of lipophilic cargos while incorporation of oleic acid-coated iron oxide into PEO-PS nanoparticles slowed the release of DiD/DiR to cell membranes. The developed in vitro and in vivo FRET imaging techniques can be used to screening stable nano-formulations for lipophilic drug delivery. PMID:24033270

  6. Lattice-patterned LC-polymer composites containing various nanoparticles as additives

    PubMed Central

    2012-01-01

    In this study, we show the effect of various nanoparticle additives on phase separation behavior of a lattice-patterned liquid crystal [LC]-polymer composite system and on interfacial properties between the LC and polymer. Lattice-patterned LC-polymer composites were fabricated by exposing to UV light a mixture of a prepolymer, an LC, and SiO2 nanoparticles positioned under a patterned photomask. This resulted in the formation of an LC and prepolymer region through phase separation. We found that the incorporation of SiO2 nanoparticles significantly affected the electro-optical properties of the lattice-patterned LC-polymer composites. This effect is a fundamental characteristic of flexible displays. The electro-optical properties depend on the size and surface functional groups of the SiO2 nanoparticles. Compared with untreated pristine SiO2 nanoparticles, which adversely affect the performance of LC molecules surrounded by polymer walls, SiO2 nanoparticles with surface functional groups were found to improve the electro-optical properties of the lattice-patterned LC-polymer composites by increasing the quantity of SiO2 nanoparticles. The surface functional groups of the SiO2 nanoparticles were closely related to the distribution of SiO2 nanoparticles in the LC-polymer composites, and they influenced the electro-optical properties of the LC molecules. It is clear from our work that the introduction of nanoparticles into a lattice-patterned LC-polymer composite provides a method for controlling and improving the composite's electro-optical properties. This technique can be used to produce flexible substrates for various flexible electronic devices. PMID:22222011

  7. Microstructural and mechanical properties of Al-4.5wt% Cu reinforced with alumina nanoparticles by stir casting method

    NASA Astrophysics Data System (ADS)

    Valibeygloo, N.; Azari Khosroshahi, R.; Taherzadeh Mousavian, R.

    2013-10-01

    The microstructure and mechanical properties of Al-4.5wt% Cu alloy reinforced with different volume fractions (1.5vol%, 3vol%, and 5vol%) of alumina nanoparticles, fabricated using stir casting method, were investigated. Calculated amounts of alumina nanoparticles (about ?50 nm in size) were ball-milled with aluminum powders in a planetary ball mill for 5 h, and then the packets of milled powders were incorporated into molten Al-4.5wt% Cu alloy. Microstructural studies of the nanocomposites reveal a uniform distribution of alumina nanoparticles in the Al-4.5wt% Cu matrix. The results indicate an outstanding improvement in compression strength and hardness due to the effect of nanoparticle addition. The aging behavior of the composite is also evaluated, indicating that the addition of alumina nanoparticles can accelerate the aging process of the alloy, resulting in higher peak hardness values.

  8. Enhanced bioavailability of orally administered flurbiprofen by combined use of hydroxypropyl-cyclodextrin and poly(alkyl-cyanoacrylate) nanoparticles.

    PubMed

    Zhao, Xiaoyun; Li, Wei; Luo, Qiuhua; Zhang, Xiangrong

    2014-03-01

    Flurbiprofen was formulated into nanoparticle suspension to improve its oral bioavailability. Hydroxypropyl-?-cyclodextrin inclusion-flurbiprofen complex (HP-?-CD-FP) was prepared, then incorporating this complex into poly(alkyl-cyanoacrylate) (PACA) nanoparticles. HP-?-CD-FP-PACA nanoparticle was prepared by the emulsion solvent polymerization method. The zeta potential was -26.8 mV, the mean volume particle diameter was 134 nm, drug encapsulation efficiency was 53.3 ± 3.6 % and concentration was 1.5 mg/mL. The bioavailability of flurbiprofen from optimized nanoparticles was assessed in male Wistar rats at a dose of 15 mg/kg. As compared to the flurbiprofen suspension, 211.6 % relative bioavailability was observed for flurbiprofen nanoparticles. The reduced particle size and increased surface area may contribute to improve oral bioavailability of flurbiprofen. PMID:23700219

  9. Intra- and interparticle magnetism of cobalt-doped iron-oxide nanoparticles encapsulated in a synthetic ferritin cage

    NASA Astrophysics Data System (ADS)

    Skoropata, E.; Desautels, R. D.; Falvo, E.; Ceci, P.; Kasyutich, O.; Freeland, J. W.; van Lierop, J.

    2014-11-01

    We present an in-depth examination of the composition and magnetism of cobalt (Co2 +)-doped iron-oxide nanoparticles encapsulated in Pyrococcus furiosus ferritin shells. We show that the Co2 + dopant ions were incorporated into the ? -Fe2O3/Fe3O4 core, with small paramagnetic-like clusters likely residing on the surface of the nanoparticle that were observed for all cobalt-doped samples. In addition, element-specific characterization using Mössbauer spectroscopy and polarized x-ray absorption indicated that Co2 + was incorporated exclusively into the octahedral B sites of the spinel-oxide nanoparticle. Comparable superparamagnetic blocking temperatures, coercivities, and effective anisotropies were obtained for 7%, 10%, and 12% cobalt-doped nanoparticles, and were only slightly reduced for 3% cobalt, indicating a strong effect of cobalt incorporation, with a lesser effect of cobalt content. Due to the regular particle size and separation that result from the use of the ferritin cage, a comparison of the effects of interparticle interactions on the disordered assembly of nanoparticles was also obtained that indicated significantly different behaviors between undoped and cobalt-doped nanoparticles.

  10. Nanoparticles as biochemical sensors

    PubMed Central

    El-Ansary, Afaf; Faddah, Layla M

    2010-01-01

    There is little doubt that nanoparticles offer real and new opportunities in many fields, such as biomedicine and materials science. Such particles are small enough to enter almost all areas of the body, including cells and organelles, potentially leading to new approaches in nanomedicine. Sensors for small molecules of biochemical interest are of critical importance. This review is an attempt to trace the use of nanomaterials in biochemical sensor design. The possibility of using nanoparticles functionalized with antibodies as markers for proteins will be elucidated. Moreover, capabilities and applications for nanoparticles based on gold, silver, magnetic, and semiconductor materials (quantum dots), used in optical (absorbance, luminescence, surface enhanced Raman spectroscopy, surface plasmon resonance), electrochemical, and mass-sensitive sensors will be highlighted. The unique ability of nanosensors to improve the analysis of biochemical fluids is discussed either through considering the use of nanoparticles for in vitro molecular diagnosis, or in the biological/biochemical analysis for in vivo interaction with the human body. PMID:24198472

  11. Traveling Nanoparticles Model

    NSDL National Science Digital Library

    2012-06-26

    This is an activity (located on page 3 of the PDF) about diffusion of small molecules across cell membranes. Learners will use gelatin to represent a cell and dye to represent molecules to model how small molecules such as nanoparticles can penetrate living environments. Relates to linked video, DragonflyTV: Nanosilver.

  12. Incorporating traffic patterns to improve delivery performance

    E-print Network

    Dickinson, Melody J

    2010-01-01

    Traffic, construction and other road hazards impact the on-time performance of companies that operate delivery fleets. This study examines how incorporating traffic patterns in vehicle route development compares with ...

  13. Biodegradable Thermoplastic Polyurethanes Incorporating Polyhedral Oligosilsesquioxane

    E-print Network

    Mather, Patrick T.

    show direct control of the final transition temperatures. Incorporating POSS into the hard segments the pure D (PDLA) or L (PLLA) enantiomer, or synthesized into a copolymer by using both. Pure racemic

  14. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III Test Dummy § 572.30 Incorporated materials. (a) The drawings and specifications referred to in this...

  15. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III Test Dummy § 572.30 Incorporated materials. (a) The drawings and specifications referred to in this...

  16. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III Test Dummy § 572.30 Incorporated materials. (a) The drawings and specifications referred to in this...

  17. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III Test Dummy § 572.30 Incorporated materials. (a) The drawings and specifications referred to in this...

  18. 49 CFR 572.30 - Incorporated materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III Test Dummy § 572.30 Incorporated materials. (a) The drawings and specifications referred to in this...

  19. Molecular determinants controlling NMDA receptor synaptic incorporation.

    PubMed

    Storey, Granville P; Opitz-Araya, Ximena; Barria, Andres

    2011-04-27

    Synaptic incorporation of NMDA receptors (NMDARs) is regulated by GluN2 subunits with different rules controlling GluN2A- and GluN2B-containing receptors; whereas GluN2B-containing receptors are constitutively incorporated into synapses, GluN2A incorporation is activity-dependent. We expressed electrophysiologically tagged NMDARs in rat hippocampal slices to identify the molecular determinants controlling the mode of synaptic incorporation of NMDARs. Expressing chimeric GluN2 subunits, we identified a putative N-glycosylation site present in GluN2B, but not in GluN2A, as necessary and sufficient to drive NMDARs into synapses in an activity-independent manner. This suggests a novel mechanism for regulating activity-driven changes and trafficking of NMDARs to the synapse. PMID:21525271

  20. Incorporation of thrombospondin into fibrin clots

    SciTech Connect

    Bale, M.D.; Westrick, L.G.; Mosher, D.F.

    1985-06-25

    Thrombospondin is a major platelet glycoprotein which is released from platelets during blood coagulation. The authors examined the interaction of thrombospondin with polymerizing fibrin. Thrombospondin, purified from human platelets and labeled with /sup 125/I, became incorporated into clots formed from both plasma and purified fibrinogen. Plasma clots contained somewhat less thrombospondin than clots formed from equivalent concentrations of fibrinogen. In plasma clots and fibrin clots formed in the presence of factor XIII, thrombospondin was cross-linked in the clot; thrombospondin in the supernatant remained largely monomeric. Cross-linking of thrombospondin by factor XIII, however, only slightly increased the amount of thrombospondin which was incorporated into the clot. In contrast, incorporation of /sup 125/I-fibronectin into clots was dependent upon cross-linking. Most of the incorporation of /sup 125/I-thrombospondin occurred during fibrin polymerization as judged by parallel studies of the incorporation of /sup 125/I-fibrinogen. The amount of thrombospondin incorporated into a clot was directly related to thrombospondin concentration and was only weakly dependent on fibrinogen concentration. Incorporation was not saturated at thrombospondin:fibrin (mol/mol) ratios as high as 2/1. Thrombospondin, however, modified the final structure of fibrin clots in a concentration-dependent manner as monitored by opacity. When tryptic digests of /sup 125/I-thrombospondin were studied, the 270-kilodalton core became incorporated into fibrin whereas the 30-kilodalton heparin binding fragment was excluded. These results indicate that thrombospondin specifically co-polymerizes with fibrin during blood coagulation and may be an important modulator of clot structure.

  1. Evaluation of polymeric nanoparticle formulations by effective imaging and quantitation of cellular uptake for controlled delivery of Doxorubicin.

    PubMed

    Win, Khin Yin; Teng, Choon Peng; Ye, Enyi; Low, Michelle; Han, Ming-Yong

    2015-03-01

    Various polymeric nanoparticles have been extensively engineered for applications in controlled drug release delivery in the last decades. Currently, there is a great demand to develop a strategy to qualitatively and quantitatively evaluate these polymeric nanoparticle formulations for producing innovative delivery systems. In this work, a screening platform is developed using luminescent quantum dots as drug model and imaging label to evaluate nanoparticle formulations incorporating either hydrophilic or hydrophobic drugs and imaging agents. It is validated that there is no influence of the incorporated entities on the cellular uptake profile. The use of quantum dots enables efficient detection and precise quantitation of cellular uptake of particles which occupy 25% of the cell volume. The correlation of quantum dot- and doxorubicin-incorporated nanoparticles is useful to develop an evaluation platform for nanoparticle formulations through imaging and quantitation. This platform is also used to observe the surface properties effect of other polymers such as chitosan and poly(ethylene) glycol on the cellular interaction and uptake. Moreover, quantum dots can be used to study microparticle theranostic delivery formulations by deliberately incorporating as visible ring surrounding the microparticles for their easy identifying and tracing in diagnostic and chemotherapeutic applications. PMID:25400129

  2. Highly luminescent material based on Alq3:Ag nanoparticles.

    PubMed

    Salah, Numan; Habib, Sami S; Khan, Zishan H

    2013-09-01

    Tris (8-hydroxyquinoline) aluminum (Alq3) is an organic semiconductor molecule, widely used as an electron transport layer, light emitting layer in organic light-emitting diodes and a host for fluorescent and phosphorescent dyes. In this work thin films of pure and silver (Ag), cupper (Cu), terbium (Tb) doped Alq3 nanoparticles were synthesized using the physical vapor condensation method. They were fabricated on glass substrates and characterized by X-ray diffraction, scanning electron microscope (SEM), energy dispersive spectroscopy, atomic force microscope (AFM), UV-visible absorption spectra and studied for their photoluminescence (PL) properties. SEM and AFM results show spherical nanoparticles with size around 70-80 nm. These nanoparticles have almost equal sizes and a homogeneous size distribution. The maximum absorption of Alq3 nanoparticles is observed at 300 nm, while the surface plasmon resonant band of Ag doped sample appears at 450 nm. The PL emission spectra of Tb, Cu and Ag doped Alq3 nanoparticles show a single broad band at around 515 nm, which is similar to that of the pure one, but with enhanced PL intensity. The sample doped with Ag at a concentration ratio of Alq3:Ag = 1:0.8 is found to have the highest PL intensity, which is around 2 times stronger than that of the pure one. This enhancement could be attributed to the surface plasmon resonance of Ag ions that might have increased the absorption and then the quantum yield. These remarkable result suggest that Alq3 nanoparticles incorporated with Ag ions might be quite useful for future nano-optoelectronic devices. PMID:23653126

  3. Highly stabilized and photoluminescence enhancement of ZnS:Mn{sup 2+} nanoparticles in biotin matrix

    SciTech Connect

    Keshari, Ashish K.; Pandey, Avinash C. [Nanophosphor Application Centre, Department of Physics, University of Allahabad, Allahabad-211 002 (India)

    2009-03-15

    We synthesized the ZnS:Mn{sup 2+} nanoparticles passivated by biocompatible layer, namely, biotin by chemical precipitation route and studied their temporal evolution for size, structure, optical, and photoluminescence stability. To monitor the structural and optoelectronic properties of the nanoparticles with time, we have characterized the grown product by x-ray diffraction, small angle x-ray scattering, UV visible, and photoluminescence spectroscopic techniques at a regular interval for a period of three months. Results showed that the properties of nanophosphors capped with biotin are remaining the same even after 3 months. Energy dispersive x-ray analysis of 3 month aged sample shows long time compatibility between ZnS:Mn{sup 2+} nanoparticles and the biotin. This is also confirmed by electron microscopy that the growth of the nanoparticles is strongly arrested by the biotin. X-ray photoelectron spectra were also recorded to show the chemical state of the elements. Enhanced ratio of Zn 2p to Mn 2p peaks in the x-ray photoelectron spectra of ZnS:Mn{sup 2+} nanoparticles shows that the Mn{sup 2+} ions are incorporated within ZnS host matrix. We found that biotin capping will enhance the luminescence from ZnS:Mn{sup 2+} nanoparticles as compared to without capped particles. Absence of biotin will gradually degrade the luminescence upon aging while drastic degradation in luminescence intensity was observed after annealing. Properties show that biotin also protected the nanoparticles from any environmental attack.

  4. Surface-independent antibacterial coating using silver nanoparticle-generating engineered mussel glue.

    PubMed

    Jo, Yun Kee; Seo, Jeong Hyun; Choi, Bong-Hyuk; Kim, Bum Jin; Shin, Hwa Hui; Hwang, Byeong Hee; Cha, Hyung Joon

    2014-11-26

    During implant surgeries, antibacterial agents are needed to prevent bacterial infections, which can cause the formation of biofilms between implanted materials and tissue. Mussel adhesive proteins (MAPs) derived from marine mussels are bioadhesives that show strong adhesion and coating ability on various surfaces even in wet environment. Here, we proposed a novel surface-independent antibacterial coating strategy based on the fusion of MAP to a silver-binding peptide, which can synthesize silver nanoparticles having broad antibacterial activity. This sticky recombinant fusion protein enabled the efficient coating on target surface and the easy generation of silver nanoparticles on the coated-surface under mild condition. The biosynthesized silver nanoparticles showed excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria and also revealed good cytocompatibility with mammalian cells. In this coating strategy, MAP-silver binding peptide fusion proteins provide hybrid environment incorporating inorganic silver nanoparticle and simultaneously mediate the interaction of silver nanoparticle with surroundings. Moreover, the silver nanoparticles were fully synthesized on various surfaces including metal, plastic, and glass by a simple, surface-independent coating manner, and they were also successfully synthesized on a nanofiber surface fabricated by electrospinning of the fusion protein. Thus, this facile surface-independent silver nanoparticle-generating antibacterial coating has great potential to be used for the prevention of bacterial infection in diverse biomedical fields. PMID:25311392

  5. Crosslinked chitosan nanoparticle formulations for delivery from pressurized metered dose inhalers.

    PubMed

    Sharma, Ketan; Somavarapu, Satyanarayana; Colombani, Agnes; Govind, Nayna; Taylor, Kevin M G

    2012-05-01

    Crosslinked chitosan nanoparticles, prepared using ionic gelation, have been successfully formulated into pressurized metered dose inhalers (pMDIs) with potential for deep lung delivery of therapeutic agents. Nanoparticles were prepared from crosslinked chitosan alone and incorporating PEG 600, PEG 1000 and PEG 5000 for dispersion in aerosol propellant, hydrofuoroalkane (HFA) 227. Spherical, smooth-surfaced, cationic particles of mean size less than 230 nm were produced. Nanoparticles were positively charged and non-aggregated at the pH of the airways. Crosslinked chitosan-PEG 1000 nanoparticles demonstrated greatest dispersibility and physical stability in HFA-227, whereas other formulations readily either creamed or sedimented. Following actuation from pMDIs, the fine particle fraction (FPF) for crosslinked chitosan-PEG 1000 nanoparticles, determined using a next generation impactor, was 34.0±1.4% with a mass median aerodynamic diameter of 4.92±0.3 ?m. The FPFs of crosslinked chitosan, crosslinked chitosan-PEG 600 and crosslinked chitosan-PEG 5000 nanoparticles were 5.7±0.9%, 11.8±2.7% and 17.0±2.1%, respectively. These results indicate that crosslinked chitosan-PEG 1000-based nanoparticles are promising candidates for delivering therapeutic agents, particularly biopharmaceuticals, using pMDIs. PMID:22245573

  6. Devitrification and recrystallization of nanoparticle-containing glycerol and PEG-600 solutions.

    PubMed

    Lv, Fukou; Liu, Baolin; Li, Weijie; Jaganathan, Ganesh K

    2014-02-01

    Nanoparticles in solution offer unique electrical, mechanical and thermal properties due to their physical presence and interaction with the state of dispersion. This work is aimed to study the effects of hydroxyapatite (HA) nanoparticles on the devitrification and recrystallization events of two important cryoprotective solutions used in cell and tissue preservation namely glycerol (60%w/w) and PEG-600 (50%w/w). HA nanoparticles (20, 40 or 60 nm) were incorporated into solutions at the content of 0.1% or 0.5%(w/w), and were studied by differential scanning calorimeter (DSC) and cryomicroscopy. The presence of nanoparticles does not change the glass transition temperatures and melting temperatures of quenched solutions, but significantly affects the behavior of devitrification and recrystallization upon warming. Cryomicroscopic investigation showed the complex interactions among solution type, nanoparticle size and nanoparticle content, which apparently influence ice crystal growth or recrystallization in the quenched dispersions. These findings have significant implications for biomaterial cryopreservation, cryosurgery, and food manufacturing. The complexity of ice crystal growth kinetics in nanoparticle-containing dispersions remains to be poorly understood at the moment. PMID:24374134

  7. Polymeric Nanoparticles with Precise Ratiometric Control over Drug Loading for Combination Therapy

    PubMed Central

    Aryal, Santosh; Hu, Che-Ming Jack; Zhang, Liangfang

    2011-01-01

    We report a novel approach for nanoparticle-based combination chemotherapy by concurrently incorporating two different types of drugs into a single polymeric nanoparticle with ratiometric control over the loading of the two drugs. By adapting metal alkoxide chemistry, we synthesize highly hydrophobic drug-poly-l-lactide (drug-PLA) conjugates, of which the polymer has the same chain length while the drug may differ. These drug-polymer conjugates are then encapsulated into lipid-coated polymeric nanoparticles through a single-step nanoprecipication method. Using doxorubicin (DOX) and camptothecin (CPT) as two model chemotherapy drugs, various ratios of DOX-PLA and CPT-PLA conjugates are loaded into the nanoparticles with over 90% loading efficiency. The resulting nanoparticles are uniform in size, size distribution and surface charge. The loading yield of DOX and CPT in the particles can be precisely controlled by simply adjusting the DOX-PLA:CPT-PLA molar ratio. Cellular cytotoxicity results show that the dual-drug loaded nanoparticles are superior to the corresponding cocktail mixtures of single-drug loaded nanoparticles. This dual-drug delivery approach offers a solution to the long-standing challenge in ratiometric control over the loading of different types of drugs onto the same drug delivery vehicle. We expect that this approach can be exploited for many types of chemotherapeutic agents containing hydroxyl groups and thus enable co-delivery of various drug combinations for combinatorial treatments of diseases. PMID:21696189

  8. Functionalized Fe3O4@Au superparamagnetic nanoparticles: in vitro bioactivity

    NASA Astrophysics Data System (ADS)

    Salado, J.; Insausti, M.; Lezama, L.; Gil de Muro, I.; Moros, M.; Pelaz, B.; Grazu, V.; de la Fuente, J. M.; Rojo, T.

    2012-08-01

    The interaction of nanoparticles with cells has been a focus of interest during the past decade. We report the fabrication and characterization of hydrosoluble Fe3O4@Au nanoparticles functionalized with biocompatible and fluorescent molecules and their interaction with cell cultures by visualizing them with confocal microscopy. Gold covered iron oxide nanoparticles were synthesized by reducing metal salts in the presence of oleylamine and oleic acid. The functionalization of these particles with an amphiphilic polymer provides a water soluble corona as well as the possibility to incorporate different molecules relevant for bio-applications such as poly(ethylene glycol), glucose or a cadaverine derived dye. The particle size, and the presence of polymer layers and conjugated molecules were characterized and confirmed by transmission electron microscopy, thermogravimetric measurements and infrared spectroscopy. A complete magnetic study was performed, showing that gold provides an optimum coating, which enhances the superparamagnetic behaviour observed above 10-15 K in this kind of nanoparticle. The interaction with cells and the cytotoxicity of the Fe3O4@Au preparations were determined upon incubation with the HeLa cell line. These nanoparticles showed no cytotoxicity when evaluated by the MTT assay and it was demonstrated that nanoparticles clearly interacted with the cells, showing a higher level of accumulation in the cells for glucose conjugated nanoparticles.

  9. Evaluation of antimicrobial activity of silver nanoparticles for carboxymethylcellulose film applications in food packaging.

    PubMed

    Siqueira, Maria C; Coelho, Gustavo F; de Moura, Márcia R; Bresolin, Joana D; Hubinger, Silviane Z; Marconcini, José M; Mattoso, Luiz H C

    2014-07-01

    In this study, silver nanoparticles were prepared and incorporated into carboxymethylcellulose films to evaluate the antimicrobial activity for food packaging applications. The techniques carried out for material characterization were: infrared spectroscopy and thermal analysis for the silver nanoparticles and films, as well as particle size distribution for the nanoparticles and water vapor permeability for the films. The antimicrobial activity of silver nanoparticles prepared by casting method was investigated. The minimum inhibitory concentration (MIC) value of the silver nanoparticles to test Gram-positive (Enterococcus faecalis) and Gram-negative (Escherichia coli) microorganisms was carried out by the serial dilution technique, tested in triplicate to confirm the concentration used. The results were developed using the Mcfarland scale which indicates that the presence or absence of turbidity tube demonstrates the inhibition of bacteria in relation to the substance inoculated. It was found that the silver nanoparticles inhibited the growth of the tested microorganisms. The carboxymethylcellulose film embedded with silver nanoparticles showed the best antimicrobial effect against Gram-positive (E. faecalis) and Gram-negative (E. coli) bacteria (0.1 microg cm(-3)). PMID:24758059

  10. Silver nanoparticles: synthesis and application in mineralization of pesticides using membrane support

    NASA Astrophysics Data System (ADS)

    Manimegalai, G.; Shanthakumar, S.; Sharma, Chandan

    2014-05-01

    Pesticides are deliberately used for controlling the pests in agriculture and public health, due to which, a part of it is present in the drinking water. Due to their widespread use, they are present in both surface and ground water. Most of the pesticides are resistant to biodegradation and are found to be carcinogenic in nature even at trace levels. Conventional methods of pesticide removal are disadvantageous due to their inherent time consumption or expensiveness. Nanoparticles alleviate both of these drawbacks and hence, they can be effectively utilized for the mineralization of pesticides. To prevent the presence of nanoparticles in the purified water after mineralization of pesticides, they need to be incorporated on a support. In earlier studies, researchers employed activated carbon and alumina as support for silver nanoparticles in pesticide mineralization. However, not many studies have been carried out on polymeric membranes as support for silver nanoparticles in the mineralization of pesticides (chlorpyrifos and malathion). With this in view, a detailed study has been carried out to estimate the mineralization potential of silver nanoparticles (synthesized using glucose) supported on cellulose acetate membrane. It is observed that the silver nanoparticles can effectively mineralize the pesticides, and the concentration of nanoparticles enhances the rate of mineralization.

  11. Quantitative analysis of the protein corona on FePt nanoparticles formed by transferrin binding

    PubMed Central

    Jiang, Xiue; Weise, Stefan; Hafner, Margit; Röcker, Carlheinz; Zhang, Feng; Parak, Wolfgang J.; Nienhaus, G. Ulrich

    2010-01-01

    Nanoparticles are finding a rapidly expanding range of applications in research and technology, finally entering our daily life in medical, cosmetic or food products. Their ability to invade all regions of an organism including cells and cellular organelles offers new strategies for medical diagnosis and therapy (nanomedicine), but their safe use requires a deep knowledge about their interactions with biological systems at the molecular level. Upon incorporation, nanoparticles are exposed to biological fluids from which they adsorb proteins and other biomolecules to form a ‘protein corona’. These nanoparticle–protein interactions are still poorly understood and quantitative studies to characterize them remain scarce. Here we have quantitatively analysed the adsorption of human transferrin onto small (radius approx. 5 nm) polymer-coated FePt nanoparticles by using fluorescence correlation spectroscopy. Transferrin binds to the negatively charged nanoparticles with an affinity of approximately 26 µM in a cooperative fashion and forms a monolayer with a thickness of 7 nm. By using confocal fluorescence microscopy, we have observed that the uptake of FePt nanoparticles by HeLa cells is suppressed by the protein corona compared with the bare nanoparticles. PMID:19776149

  12. Targeted nanoparticles for simultaneous delivery of chemotherapeutic and hyperthermia agents--an in vitro study.

    PubMed

    Srinivasan, Supriya; Manchanda, Romila; Lei, Tingjun; Nagesetti, Abhignyan; Fernandez-Fernandez, Alicia; McGoron, Anthony J

    2014-07-01

    The purpose of this study was to prepare targeted Poly lactide-co-glycolide (PLGA) nanoparticles with simultaneous entrapment of indocyanine green (ICG) and doxorubicin (DOX) by surface decorating them with tumor specific monoclonal antibodies in order to achieve simultaneous therapy and imaging. ICG was chosen as an imaging and hyperthermia agent and DOX was used as a chemotherapeutic agent. ICG and DOX were incorporated into PLGA nanoparticles using the oil-in-water emulsion solvent evaporation technique. These nanoparticles were further surface decorated with antibodies against Human Epithelial Receptor-2 (HER-2) using carbodiimide chemistry. The uptake of antibody conjugated ICG-DOX-PLGA nanoparticles (AIDNP) was enhanced in SKOV-3 (HER-2 overexpressing cell lines) compared to their non-conjugated counterparts (ICG-DOX-PLGA nanoparticles (IDNP)). The uptake of antibody conjugated ICG-DOX-PLGA nanoparticles, however, was similar in MES-SA and MES-SA/Dx5 cancer cells (HER-2 negative cell lines), which were used as negative controls. The cytotoxicity results after laser treatment (808 nm, 6.7 W/cm(2)) showed an enhanced toxicity in treatment of SKOV-3. The negative controls exhibited comparable cytotoxicity with or without exposure to the laser. Thus, this study showed that these antibody conjugated ICG-DOX-PLGA nanoparticles have potential for combinatorial chemotherapy and hyperthermia. PMID:24859437

  13. Development of a chitosan-based nanoparticle formulation for delivery of a hydrophilic hexapeptide, dalargin.

    PubMed

    Chen, Yan; Siddalingappa, Basavaraj; Chan, Phoebe H H; Benson, Heather A E

    2008-01-01

    Nanoparticle based delivery systems can offer opportunities for targeting, controlled release, and enhanced stability of their drug, protein, or gene therapy payload. This study investigated the use of chitosan in combination with the ionic additives sulfobutyl-ether-7-beta-cyclodextrin (SB-CD) or SB-CD/dextran sulfate (SB-CD/DS) mixture in comparison with chitosan: DS in the formulation of nanoparticles incorporating the hexapeptide dalargin. The physical characteristics (particle size, zeta potential), entrapment and loading efficiency, and release of dalargin were quantified. It was demonstrated that anionic cyclodextrin, SB-CD, can be used in complex coacervation with chitosan, with and without the presence of DS, to form nanoparticles. The presence of SB-CD or DS in the nanoparticle formulation and the weight ratio of chitosan to anionic additive(s) influenced the physical properties of the nanoparticles and their ability to carry dalargin. In addition, the particle size of nanoparticles was also affected by the molecular weight of chitosan and DS. The use of either DS or SB-CD/DS mixture produced chitosan nanoparticles with small particle size, high dalargin entrapment efficiency, enhanced peptide stability, and sustained release characteristics. PMID:18655140

  14. Novel docetaxel-loaded nanoparticles based on PCL-Tween 80 copolymer for cancer treatment

    PubMed Central

    Ma, Yuandong; Zheng, Yi; Zeng, Xiaowei; Jiang, Liqin; Chen, Hongbo; Liu, Ranyi; Huang, Laiqiang; Mei, Lin

    2011-01-01

    Background The formulation of docetaxel available for clinical use (Taxotere®) contains a high concentration of polysorbate 80 (Tween 80). After incorporation of Tween 80 into poly-?-caprolactone (PCL)-Tween 80 copolymer, the relative amount of Tween 80 should be decreased and the advantages of PCL and Tween 80 should be combined. Methods A novel PCL-Tween 80 copolymer was synthesized from ?-caprolactone and Tween 80 in the presence of stannous octoate as a catalyst via ring opening polymerization. Two types of nanoparticle formulation were made from commercial PCL and a self-synthesized PCL-Tween 80 copolymer using a modified solvent extraction/evaporation method. Results The nanoparticles were found by field emission scanning electron microscopy to have a spherical shape and be 200 nm in diameter. The copolymers could encapsulate 10% of the drug in the nanoparticles and release 34.9% of the encapsulated drug over 28 days. PCL-Tween 80 nanoparticles could be internalized into the cells and had higher cellular uptake than the PCL nanoparticles. The drug-loaded PCL-Tween 80 nanoparticles showed better in vitro cytotoxicity towards C6 cancer cells than commercial Taxotere at the same drug concentration. Conclusion Nanoparticles using PCL-Tween 80 copolymer as drug delivery vehicles may have a promising outcome for cancer patients. PMID:22114498

  15. Preparation of bio-compatible boron nanoparticles and novel mesoporous silica nanoparticles for bio-applications

    NASA Astrophysics Data System (ADS)

    Gao, Zhe

    This dissertation presents the synthesis and characterization of several novel inorganic and hybrid nanoparticles, including the bio-compatible boron nanoparticles (BNPs) for boron neutron capture therapy (BNCT), tannic acid-templated mesoporous silica nanoparticles and degradable bridged silsesquioxane silica nanoparticles. Chapter 1 provides background information of BNCT and reviews the development of design and synthesizing silica nanoparticles and the study of silica material degradability. Chapter 2 describes the preparation and characterization of dopamine modified BNPs and the preliminary cell study of them. The BNPs were first produced via ball milling, with fatty acid on the surface to stabilize the combustible boron elements. This chapter will mainly focus on the ligand-exchange strategy, in which the fatty acids were replaced by non-toxic dopamines in a facile one-pot reaction. The dopamine-coated BNPs (DA-BNPs) revealed good water dispersibility and low cytotoxicity. Chapter 3 describes the synthesis of tannic acid template mesoporous silica nanoparticles (TA-TEOS SiNPs) and their application to immobilize proteins. The monodispersed TA SiNPs with uniform pore size up to approximately 13 nm were produced by utilizing tannic acid as a molecular template. We studied the influence of TA concentration and reaction time on the morphology and pore size of the particles. Furthermore, the TA-TEOS particles could subsequently be modified with amine groups allowing them to be capable of incorporating imaging ligands and other guest molecules. The ability of the TA-TEOS particles to store biomolecules was preliminarily assessed with three proteins of different charge characteristics and dimensions. The immobilization of malic dehydrogenase on TA-TEOS enhanced the stability of the enzyme at room temperature. Chapter 4 details the synthesis of several bridged silsesquioxanes and the preparation of degradable hybrid SiNPs via co-condensation of bridged silsesquioxanes with tetraethoxysilane. In vivo studies show that the solid SiNPs accumulate in many organs due to the lack of degradability. The aim of our work is to address this shortcoming by producing novel degradable SiNPs. Bridged silsesquioxanes were used as the precursors of the particles, and upon cleavage of the carbamate groups when brought into contact with aqueous media, the particles degraded into porous structures.

  16. Pegylated siRNA-loaded calcium phosphate nanoparticle-driven amplification of cancer cell internalization in vivo

    PubMed Central

    Tobin, Lisa A.; Xie, Yili; Tsokos, Maria; Chung, Su I.; Merz, Allison A.; Arnold, Michael A.; Li, Guang; Malech, Harry L.; Kwong, King F.

    2013-01-01

    The cell membrane is a critical barrier to effective delivery for many therapeutics, including those which are nanoparticle-based. Improving nanoparticle transport across the cell membrane remains a fundamental challenge. Cancer cells preferentially internalized pegylated calcium phosphate nanoparticles over normal epithelial cells. Furthermore, non-cytotoxic levels of doxorubicin markedly amplified this difference by increasing free unbound caveolin-1 and resulted in enhanced caveolin-mediated nanoparticle endocytosis in cancer cells. Engineered pegylated siRNA-loaded triple-shell calcium phosphate nanoconstructs incorporating ultra-low levels of doxorubicin recapitulated these effects and delivered increased numbers of siRNA into cancer cells with target-specific results. Systemic administration of nanoparticles in vivo demonstrated highly preferential entry into tumors, little bystander organ biodistribution, and significant tumor growth arrest. In conclusion, siRNA-loaded calcium phosphate nanoparticles incorporating non-cytotoxic amounts of doxorubicin markedly enhances nanoparticle internalization and results in increased payload delivery with concomitant on-target effects. PMID:23369215

  17. Nanoparticle Measurements and Standards for Biomedical and

    E-print Network

    Magee, Joseph W.

    for physical and biological characterization of nanoparticles for imaging, diagnosis and therapy. · New consensus standards for characterization of biomedical nanoparticles are currently under development within a nanoparticle measurement infrastructure. Standards In 2008 NIST issued its first "nano" reference materials

  18. Engineering nanoparticle antitoxins utilizing aromatic interactions.

    PubMed

    Weisman, Adam; Chen, Yingyao Allie; Hoshino, Yu; Zhang, Huiting; Shea, Kenneth

    2014-09-01

    Methicillin resistant Staphylococcus aureus (MRSA) is a highly virulent bacterium capable of inflicting severe infections. This pathogen has a long history of developing resistance to antibacterial drugs, and many phenotypes are capable of disabling the host immune response by releasing peptide and protein toxins with the capacity to lyse human polymorphonuclear neutrophils. The peptide phenol-soluble modulin ?3 (PSM?3) has been identified as an important toxin released by the most virulent strains of MRSA. A library of polymer nonaparticles was synthesized by precipitation polymerization and screened for their ability to bind and neutralize this toxin. To generate high affinity, monomers were chosen to compliment the functional groups of PSM?3. Nanoparticles incorporating aromatic monomers provided a high affinity for the peptide and were effective at neutralizing its toxicity in vitro. PMID:25093686

  19. Piezoelectric nanoparticle-polymer composite foams.

    PubMed

    McCall, William R; Kim, Kanguk; Heath, Cory; La Pierre, Gina; Sirbuly, Donald J

    2014-11-26

    Piezoelectric polymer composite foams are synthesized using different sugar-templating strategies. By incorporating sugar grains directly into polydimethylsiloxane mixtures containing barium titanate nanoparticles and carbon nanotubes, followed by removal of the sugar after polymer curing, highly compliant materials with excellent piezoelectric properties can be fabricated. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio which gave an upper bound on the porosity of 73% and a lower bound on the elastic coefficient of 32 kPa. The electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs, giving piezoelectric coefficient values of ?112 pC/N and a power output of ?18 mW/cm3 under a load of 10 N for the highest porosity samples. These novel materials should find exciting use in a variety of applications including energy scavenging platforms, biosensors, and acoustic actuators. PMID:25353687

  20. Polymer-coated mesoporous silica nanoparticles for the controlled release of macromolecules.

    PubMed

    Bhattacharyya, Sanjib; Wang, Henson; Ducheyne, Paul

    2012-09-01

    With the goal of achieving constant release of large biological molecules over an extended period of time we focused on hybrid inorganic/organic nanoparticles. We synthesized poly(ethylene glycol) (PEG)-coated mesoporous silica nanoparticles (MSNs) with incorporated trypsin inhibitor (TI), a model protein molecule for growth factors. Due to the goal of incorporating large protein molecules the pore size of the as-synthesized MSNs was expanded by a hydrothermal treatment prior to TI incorporation. In vitro release from the MSNs without the thin polymer film shows an initial burst followed by continuous release. In the case of polymer-coated MSNs the initial burst release was completely suppressed and approximate zero order release was achieved for 4 weeks. PMID:22688089

  1. Evaluation of monolayer protected metal nanoparticle technology

    E-print Network

    Wu, Diana J

    2005-01-01

    Self assembling nanostructured nanoparticles represent a new class of synthesized materials with unique functionality. Such monolayer protected metal nanoparticles are capable of resisting protein adsorption, and if utilized ...

  2. Photoacoustic signal amplification through plasmonic nanoparticle aggregation

    PubMed Central

    Bayer, Carolyn L.; Nam, Seung Yun; Chen, Yun-Sheng; Emelianov, Stanislav Y.

    2013-01-01

    Abstract. Photoacoustic imaging, using targeted plasmonic metallic nanoparticles, is a promising noninvasive molecular imaging method. Analysis of the photoacoustic signal generated by plasmonic metallic nanoparticles is complex because of the dependence upon physical properties of both the nanoparticle and the surrounding environment. We studied the effect of the aggregation of gold nanoparticles on the photoacoustic signal amplitude. We found that the photoacoustic signal from aggregated silica-coated gold nanoparticles is greatly enhanced in comparison to disperse silica-coated gold nanoparticles. Because cellular uptake and endocytosis of nanoparticles results in their aggregation, these results have important implications for the application of plasmonic metallic nanoparticles towards quantitative molecular imaging. PMID:23288414

  3. Recent advances and future directions in amphiphilic cyclodextrin nanoparticles.

    PubMed

    Bilensoy, Erem; Hincal, A Atilla

    2009-11-01

    Cyclodextrins are known to be promising excipients in the pharmaceutical industry, with their ability to include hydrophobic guest molecules masking the physicochemical properties of the guest, such as poor water solubility, stability problems and undesired side effects. These enabling excipients, which are produced on a large scale and incorporated into various marketed products worldwide, are now modified to render amphiphilic properties that enable them to be used to prepare nanoparticles. Amphiphilic cyclodextrins have the ability to form nanoparticles without the presence of a surfactant by different preparation techniques that are discussed in this review. Classification and physicochemical properties of these interesting molecules as well as the efficacy and safety of nanoparticles prepared from different amphiphilic cyclodextrins are discussed in light of the current literature work with in vitro and in vivo findings. Cyclodextrin nanoparticles of different nature effectively carry drugs or molecules with bioavailability problems arising from poor aqueous solubility, stability under physiological conditions or side effects associated with the molecule itself or excipients used in the formulation of these problems drugs. In conclusion, amphiphilic cyclodextrins emerge as promising alternatives for tumor drug delivery and passive and active targeting with non-toxic, non-hemolytic properties as injectable, nanosized carriers. PMID:19705965

  4. Green synthesis and applications of Au-Ag bimetallic nanoparticles.

    PubMed

    Meena Kumari, M; Jacob, John; Philip, Daizy

    2015-02-25

    This paper reports for the first time the synthesis of bimetallic nanoparticles at room temperature using the fruit juice of pomegranate. Simultaneous reduction of gold and silver ions in different molar ratios leads to the formation of alloy as well as core-shell nanostructures. The nanoparticles have been characterized using UV-vis spectroscopy, transmission electron microscopy, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The synthesized alloy particles are used as catalysts in the reduction of 2-, 3-, 4-nitrophenols to the corresponding amines and in the degradation of methyl orange. The reduction kinetics for all the reactions follows pseudo-first order. The rate constants follow the order k4-nitrophenolincorporation of the alloy nanoparticles enhances the thermal conductivity of the base fluid (water) showing nanofluid application. The nitric oxide and hydroxyl radical scavenging activity shown by the nanoparticles promise the potential application in biomedical field. PMID:25218228

  5. Green synthesis and applications of Au-Ag bimetallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Meena Kumari, M.; Jacob, John; Philip, Daizy

    2015-02-01

    This paper reports for the first time the synthesis of bimetallic nanoparticles at room temperature using the fruit juice of pomegranate. Simultaneous reduction of gold and silver ions in different molar ratios leads to the formation of alloy as well as core-shell nanostructures. The nanoparticles have been characterized using UV-vis spectroscopy, transmission electron microscopy, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The synthesized alloy particles are used as catalysts in the reduction of 2-, 3-, 4-nitrophenols to the corresponding amines and in the degradation of methyl orange. The reduction kinetics for all the reactions follows pseudo-first order. The rate constants follow the order k4-nitrophenol < k2-nitrophenol < k3-nitrophenol. Thermal conductivity is measured as a function of volume fraction and it is observed that the incorporation of the alloy nanoparticles enhances the thermal conductivity of the base fluid (water) showing nanofluid application. The nitric oxide and hydroxyl radical scavenging activity shown by the nanoparticles promise the potential application in biomedical field.

  6. Controlled Assembly of Viral Surface Proteins into Biological Nanoparticles

    NASA Astrophysics Data System (ADS)

    Nakatani-Webster, Eri

    In recent years, therapeutic use of engineered particles on the 1-1,000 nm scale has gained popularity; these nanoparticles have been developed for use in drug delivery, gene therapy, vaccine preparation, and diagnostics. Often, viral proteins are utilized in the design of such species, and outlined here are completed studies on the in vitro assembly of nanoparticles derived from two very different viral systems. The incorporation of the human immunodeficiency virus (HIV) envelope glycoprotein precursor gp160 into phospholipid bilayer nanodiscs is discussed as a potential platform for vaccine design; efforts were successful, however yield currently limits the practical application of this approach. The utility of bacteriophage lambda procapsids and virus-like particles in therapeutic nanoparticle design is also outlined, as are efforts toward the structural and thermodynamic characterization of a urea-triggered capsid maturation event. It is demonstrated that lambda virus-like particles can be assembled from purified capsid and scaffolding proteins, and that these particles undergo urea-triggered maturation and in vitro decoration protein addition similar to that seen in lambda procapsids. The studies on lambda provided materials for the further development of nanoparticles potentially useful in a clinical setting, as well as shedding light on critical viral assembly and maturation events as they may take place in vivo.

  7. Role of chitosan nanoparticles in the oral absorption of Gemcitabine.

    PubMed

    Derakhshandeh, Katayoun; Fathi, Sahar

    2012-11-01

    Gemcitabine is a known cytotoxic agent with a wide spectrum of antitumor activity. It has been employed in therapeutic regimens for various malignancies such as the lung, ovary, breast, and bladder cancers. It also has been used in the treatment of pancreatic cancer, in combination chemotherapy of non-small cell lung cancer (NSCLC) and in leukemia. Its effect results from incorporation into DNA with subsequent inhibition of cell proliferation. Unfortunately, Gemcitabine is rapidly metabolized by the so-called cytidine-deaminase which limits its efficacy. Because of extensive deamination by intestinal cells, its oral administration results in very low bioavailability. The aim of this study was to introduce an oral formulation of the drug for the first time and improve its physicochemical properties. Chitosan nanoparticles containing were produced based on ionic gelation method and tripolyphosphate (TPP). Physicochemical properties such as particle size and shape, loading efficiency and release rate were evaluated. Oral absorption of both free and nanoparticle-loaded drugs was measured using the rat intestinal sac model. The Gemcitabine-loaded chitosan nanoparticles were spherical with a mean size of 95±8 nm and high drug loading (63%). The nanoparticles showed controlled release pattern characterized by a fast initial release (61%) during the first 8h, followed by slower and continuous release (74.66%). The absorption study showed that Gemcitabine intestinal transport increased 3-5 folds by loading in chitosan nanocarrier. PMID:22909993

  8. Nanoparticles for Detection and Diagnosis

    PubMed Central

    Agasti, Sarit S.; Rana, Subinoy; Park, Myoung-Hwan; Kim, Chae Kyu; You, Chang-Cheng; Rotello, Vincent M.

    2009-01-01

    Nanoparticle-based platforms for identification of chemical and biological agents offer substantial benefits to biomedical and environmental science. These platforms benefit from the availability of a wide variety of core materials as well as the unique physical and chemical properties of these nanoscale materials. This review surveys some of the emerging approaches in the field of nanoparticle based detection systems, highlighting the nanoparticle based screening methods for metal ions, proteins, nucleic acids, and biologically relevant small molecules. PMID:19913581

  9. Nanobiotechnology today: focus on nanoparticles

    PubMed Central

    Soloviev, Mikhail

    2007-01-01

    In the recent years the nanobiotechnology field and the Journal of Nanobiotechnology readership have witnessed an increase in interest towards the nanoparticles and their biological effects and applications. These include bottom-up and molecular self-assembly, biological effects of naked nanoparticles and nano-safety, drug encapsulation and nanotherapeutics, and novel nanoparticles for use in microscopy, imaging and diagnostics. This review highlights recent Journal of Nanobiotechnology publications in some of these areas . PMID:18163916

  10. The mutual influence of two different dyes on their sensitized fluorescence (cofluorescence) in nanoparticles from complexes

    NASA Astrophysics Data System (ADS)

    Mironov, L. Yu.; Sveshnikova, E. B.; Ermolaev, V. L.

    2013-10-01

    We have studied the fluorescence sensitization and quenching for pairs of different dyes simultaneously incorporated into nanoparticles from complexes M(diketone)3phen, where M(III) is La(III), Lu(III), or Sc(III); diketone is p-phenylbenzoyltrifluoroacetone (PhBTA) or naphthoyltrifluoroacetone (NTA); and phen is 1,10-phenanthroline. We have shown that, upon formation of nanoparticles in the solution in the presence of two dyes the concentrations of which are either comparable with or lower than the concentration of nanoparticles (<20 nM), the intensities of the sensitized fluorescence of dyes in nanoparticles in binary solutions and in solutions of either of the dyes coincide. We have found that the intensity of sensitized fluorescence of small (<20 nM) concentrations of rhodamine 6G (R6G) or Nile blue (NB) increases by an order of magnitude upon simultaneous introduction into nanoparticles of 1 ?M of coumarin 30 (C30), while the intensity of fluorescence of C30 sensitized by complexes decreases by an order of magnitude. The same effect is observed as 1 ?M of R6G are introduced into nanoparticles with NB ([NB] ? 20 nM). The increase in the fluorescence of dye molecules upon their incorporation from the solution into nanoparticles from complexes is noticeably lower than that expected from the proposed ratio of concentrations of complexes and dyes in nanoparticles. Analysis of the obtained data indicates that the introduction of large concentrations of C30 or R6G dyes into nanoparticles makes it possible to prevent large energy losses due to impurities or upon transition to a triplet state that arises during the migration of the excitation energy over S 1 levels of complexes. Energy accumulated by these dyes is efficiently transferred to another dye that is present in the solution at lower concentrations and that has a lower-lying S 1 level, which makes it possible to increase its fluorescence by an order of magnitude upon its incorporation into nanoparticles.

  11. Some optical and catalytic properties of metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Tabor, Christopher Eugene

    Nanomaterials have been the focus of many previous publications and studies. This fact is due to the wealth of new and tunable properties that exist when a material is confined in size. This thesis discusses some of those properties pertaining to metallic nanoparticles. The primarily focus is on the plasmonic properties of gold nanoparticles with a final chapter discussing nanocatalysis and the nature of nanocatalytic reactions. The strong electromagnetic field that is induced at the surface of a plasmonic nanoparticle can be utilized for many important applications, including spectroscopic enhancements for molecular sensors and electromagnetic waveguides for sub-wavelength light manipulation. For many of these applications, it is necessary to use two or more nanoparticles in close proximity with overlapping plasmonic fields. Knowledge of how these overlapping fields are affected by the particle orientation, size, and shape is critically important, not only in understanding the fundamental properties of plasmons but also in designing future architectures that employ plasmonic particles. The field of metallic nanoparticles is introduced from its beginning, with artistic use as early as the 4th century AD through current applications and understanding. The broad spectrum of current methodologies for fabricating nanoparticles is discussed, from top down methods using lithography and from bottom up methods using metal salt reduction in solution. There are several methods used in this thesis, all of which are discussed in great detail, with some details pertaining to the specific instrumentation used here. The first study is on the transfer of surface supported gold nanoprisms from a substrate into solution using photo-thermal heating with a femtosecond pulse coincident with the plasmon resonance frequency of the nanoprisms. The mechanism of transfer is discovered to be due to super heating of solvent molecules dissolved at the particle-substrate interface. This process is studied as a function of irradiance fluence and solvent. The stability of the unprotected nanoprisms in solution is discussed. This technique has applications for creating a colloidal suspension of nanoparticle without a surfactant layer covering the surface. The particles can be chemically functionalized with any desired moiety for specific solution phase applications. The second study is on the fundamentals of plasmonic near-field coupling between two plasmonic nanoparticles as a function of the nanoparticle size, shape, and orientation. Experimental results using electron beam lithography fabricated samples are used to better understand the plasmonic coupling between dimers. Previously, the coupling between plasmonic fields around nanoparticles has been described as a near-exponential decay dependence on interparticle separation. This decay was proposed to be consistent among all sizes and shapes of nanoparticles, which was quantitatively measured using the best-fit decay length in units of the nanoparticle size. Experimental proof is presented of the shape dependence of this decay length, which is roughly 50% greater for nanoprisms than for nanodiscs, nanospheres, and nanoellipses. This was shown using simulated and experimental data. Using simulated results, the coupling decay length was shown to be independent of size for all nanoparticle shapes examined. Additionally, the effect of particle orientation on the coupling of the induced nearfields of the plasmonic particles is intensely investigated. Systematic studies using a combination of experimental samples and computer simulations are presented that examine the role of one particle's orientation to another within a plasmonic dimer system. This dependence is compared to the mathematically derived dependence and shown to be in excellent agreement. The plasmon hybridization method is given as a straightforward method to understand and predict the effect of plasmon near-field coupling on orientation. Previous methods used to understand the effect of separation on the plasmon coupling are incorporated i

  12. Safety of Nanoparticles in Medicine.

    PubMed

    Wolfram, Joy; Zhu, Motao; Yang, Yong; Shen, Jianliang; Gentile, Emanuela; Paolino, Donatella; Fresta, Massimo; Nie, Guangjun; Chen, Chunying; Shen, Haifa; Ferrari, Mauro; Zhao, Yuliang

    2014-08-01

    Nanomedicine involves the use of nanoparticles for therapeutic and diagnostic purposes. During the past two decades, a growing number of nanomedicines have received regulatory approval and many more show promise for future clinical translation. In this context, it is important to evaluate the safety of nanoparticles in order to achieve biocompatibility and desired activity. However, it is unwarranted to make generalized statements regarding the safety of nanoparticles, since the field of nanomedicine comprises a multitude of different manufactured nanoparticles made from various materials. Indeed, several nanotherapeutics that are currently approved, such as Doxil and Abraxane, exhibit fewer side effects than their small molecule counterparts, while other nanoparticles (e.g. metallic and carbon-based particles) tend to display toxicity. However, the hazardous nature of certain nanomedicines could be exploited for the ablation of diseased tissue, if selective targeting can be achieved. This review discusses the mechanisms for molecular, cellular, organ, and immune system toxicity, which can be observed with a subset of nanoparticles. Strategies for improving the safety of nanoparticles by surface modification and pretreatment with immunomodulators are also discussed. Additionally, important considerations for nanoparticle safety assessment are reviewed. In regards to clinical application, stricter regulations for the approval of nanomedicines might not be required. Rather, safety evaluation assays should be adjusted to be more appropriate for engineered nanoparticles. PMID:25090989

  13. Magnetic Nanoparticle Sensors

    PubMed Central

    Koh, Isaac; Josephson, Lee

    2009-01-01

    Many types of biosensors employ magnetic nanoparticles (diameter = 5–300 nm) or magnetic particles (diameter = 300–5,000 nm) which have been surface functionalized to recognize specific molecular targets. Here we cover three types of biosensors that employ different biosensing principles, magnetic materials, and instrumentation. The first type consists of magnetic relaxation switch assay-sensors, which are based on the effects magnetic particles exert on water proton relaxation rates. The second type consists of magnetic particle relaxation sensors, which determine the relaxation of the magnetic moment within the magnetic particle. The third type is magnetoresistive sensors, which detect the presence of magnetic particles on the surface of electronic devices that are sensitive to changes in magnetic fields on their surface. Recent improvements in the design of magnetic nanoparticles (and magnetic particles), together with improvements in instrumentation, suggest that magnetic material-based biosensors may become widely used in the future. PMID:22408498

  14. Nanoparticles for neuroimaging

    NASA Astrophysics Data System (ADS)

    Re, F.; Moresco, R.; Masserini, M.

    2012-02-01

    The advent of nanotechnology has introduced a variety of novel exciting possibilities into the medical and clinical field. Nanoparticles, ultra-small object sized between 100 and 1 nm, are promising diagnostic tools for various diseases among other devices, thanks to the possibility of their functionalization allowing the selective targeting of organs, tissues and cells and to facilitate their transport to primary target organs. However, brain targeting represents a still unresolved challenge due to the presence of the blood-brain barrier, a tightly packed layer of endothelial cells that prevents unwanted substances entering the central nervous system. We review a range of nanoparticles suitable for in vivo diagnostic imaging of neurodegenerative diseases and brain disorders, highlighting the possibility to potentially increase their efficiency and kinetics of brain-targeting. We also review a range of imaging techniques with an emphasis on most recently introduced molecular imaging modalities, their current status and future potential.

  15. Photoluminescence by Interstellar Nanoparticles

    SciTech Connect

    Witt, Adolf N. (University of Toledo) [University of Toledo

    2004-04-21

    Dust grains in interstellar space are an all-pervasive component of the Universe that affect our perception of virtually every cosmic phenomenon. They play important roles in processes like star formation, formation of molecules and formation of terrestrial planets, to name just a few. Yet, their nature, size, structure, and composition are only poorly understood. I shall report on new investigations of optical luminescence emanating from dust grains that reveal the presence of nanoparticle components of dust, most likely polycyclic aromatic hydrocarbons and tiny semiconductor nanocrystals, e.g. silicon nanoparticles. Coordinated laboratory studies of such small particles would greatly aid our efforts of arriving at definitive identifications of the luminescent astronomical dust sources.

  16. Nanoparticles in dermatology

    Microsoft Academic Search

    Dimitrios Papakostas; Fiorenza Rancan; Wolfram Sterry; Ulrike Blume-Peytavi; Annika Vogt

    Recent advances in the field of nanotechnology have allowed the manufacturing of elaborated nanometer-sized particles for\\u000a various biomedical applications. A broad spectrum of particles, extending from various lipid nanostructures such as liposomes\\u000a and solid lipid nanoparticles, to metal, nanocrystalline and polymer particles have already been tested as drug delivery systems\\u000a in different animal models with remarkable results, promising an extensive

  17. Size dependent phase diagrams of Nickel-Carbon nanoparticles

    E-print Network

    Magnin, Yann; Amara, Hakim; Ducastelle, François; Bichara, Christophe

    2015-01-01

    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 nanometers (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 be taken into account in our understanding of the nanotube growth mechanisms.

  18. Probing the switching mechanism in ZnO nanoparticle memristors

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Beirne, Gareth J.; Kamita, Gen; Lakhwani, Girish; Wang, Jianpu; Greenham, Neil C.

    2014-09-01

    We investigate the resistance switching mechanism in memristors based on colloidal ZnO nanoparticles using electroabsorption (EA) spectroscopy. In this EA experiment, we incorporate a small amount of low-bandgap polymer, poly(9,9-dioctylfluorene-co-benzothiadiazole), as a probe molecule in ZnO-nanoparticle memristors. By characterizing this polymer, we can study the change of built-in potential (VBI) in the device during the resistance switching process without disturbing the resistance state by the EA probe light. Our results show that VBI increases when the device is switched to the high resistance state, suggesting a shift of effective workfunction of the electrode. Thus, we attribute the resistance switching to the field-dependent migration of oxygen vacancies associated with the adsorption and desorption of oxygen molecules at the Al/ZnO interface. This process results in the modulation of the interfacial injection barrier, which governs the resistance state of the device.

  19. Room-temperature ferromagnetism in hydrogenated ZnO nanoparticles

    SciTech Connect

    Xue, Xudong; Liu, Liangliang; Wang, Zhu; Wu, Yichu, E-mail: ycwu@whu.edu.cn [School of Physics and Technology, Hubei Nuclear Solid Physics Key Laboratory, Wuhan University, Wuhan 430072 (China)

    2014-01-21

    The effect of hydrogen doping on the magnetic properties of ZnO nanoparticles was investigated. Hydrogen was incorporated by annealing under 5% H{sub 2} in Ar ambient at 700?°C. Room-temperature ferromagnetism was induced in hydrogenated ZnO nanoparticles, and the observed ferromagnetism could be switched between “on” and “off” states through hydrogen annealing and oxygen annealing process, respectively. It was found that Zn vacancy and OH bonding complex (V{sub Zn}?+?OH) was crucial to the observed ferromagnetism by using the X-ray photoelectron spectroscopy and positron annihilation spectroscopy analysis. Based on first-principles calculations, V{sub Zn}?+?OH was favorable to be presented due to the low formation energy. Meanwhile, this configuration could lead to a magnetic moment of 0.57??{sub B}. The Raman and photoluminescence measurements excluded the possibility of oxygen vacancy as the origin of the ferromagnetism.

  20. Towards thiol functionalization of vanadium pentoxide nanotubes using gold nanoparticles

    SciTech Connect

    Lavayen, V. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); O'Dwyer, C. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)]. E-mail: codwyer@tyndall.ie; Cardenas, G. [Departamento de Polimeros, Facultad de Ciencias Quimicas, Universidad de Concepcion, P.O. Box 160-C, Concepcion (Chile); Gonzalez, G. [Department of Chemistry, Faculty of Science, Universidad de Chile, P.O. Box 653, Santiago (Chile); Sotomayor Torres, C.M. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

    2007-04-12

    Template-directed synthesis is a promising route to realize vanadate-based 1-D nanostructures, an example of which is the formation of vanadium pentoxide nanotubes and associated nanostructures. In this work, we report the interchange of long-chained alkyl amines with alkyl thiols. This reaction was followed using gold nanoparticles prepared by the Chemical Liquid Deposition (CLD) method with an average diameter of {approx}0.9nm and a stability of {approx}85 days. V{sub 2}O{sub 5} nanotubes (VOx-NTs) with lengths of {approx}2{mu}m and internal hollow diameters of 20-100nm were synthesized and functionalized in a Au-acetone colloid with a nominal concentration of {approx}4x10{sup -3}mol dm{sup -3}. The interchange reaction with dodecylamine is found only to occur in polar solvents and incorporation of the gold nanoparticles is not observed in the presence of n-decane.

  1. Multispectral guided fluorescence diffuse optical tomography using upconverting nanoparticles

    SciTech Connect

    Svenmarker, Pontus, E-mail: pontus.svenmarker@physics.umu.se [Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Department of Physics, Umeå University, SE-901 87 Umeå (Sweden); Centre for Microbial Research (UCMR), Umeå University, SE-901 87 Umeå (Sweden); Xu, Can T.; Liu, Haichun; Wu, Xia; Andersson-Engels, Stefan [Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden)

    2014-02-17

    We report on improved image detectability for fluorescence diffuse optical tomography using upconverting nanoparticles doped with rare-earth elements. Core-shell NaYF{sub 4}:Yb{sup 3+}/Er{sup 3+}@NaYF{sub 4} upconverting nanoparticles were synthesized through a stoichiometric method. The Yb{sup 3+}/Er{sup 3+} sensitizer-activator pair yielded two anti-Stokes shifted fluorescence emission bands at 540?nm and 660?nm, here used to a priori estimate the fluorescence source depth with sub-millimeter precision. A spatially varying regularization incorporated the a priori fluorescence source depth estimation into the tomography reconstruction scheme. Tissue phantom experiments showed both an improved resolution and contrast in the reconstructed images as compared to not using any a priori information.

  2. Multispectral guided fluorescence diffuse optical tomography using upconverting nanoparticles

    NASA Astrophysics Data System (ADS)

    Svenmarker, Pontus; Xu, Can T.; Liu, Haichun; Wu, Xia; Andersson-Engels, Stefan

    2014-02-01

    We report on improved image detectability for fluorescence diffuse optical tomography using upconverting nanoparticles doped with rare-earth elements. Core-shell NaYF4:Yb3+/Er3+@NaYF4 upconverting nanoparticles were synthesized through a stoichiometric method. The Yb3+/Er3+ sensitizer-activator pair yielded two anti-Stokes shifted fluorescence emission bands at 540 nm and 660 nm, here used to a priori estimate the fluorescence source depth with sub-millimeter precision. A spatially varying regularization incorporated the a priori fluorescence source depth estimation into the tomography reconstruction scheme. Tissue phantom experiments showed both an improved resolution and contrast in the reconstructed images as compared to not using any a priori information.

  3. Structural incorporation of Cm(III) in trioctahedral smectite hectorite: A time-resolved laser fluorescence spectroscopy (TRLFS) study

    NASA Astrophysics Data System (ADS)

    Brandt, Heike; Bosbach, Dirk; Panak, Petra J.; Fanghänel, Thomas

    2007-01-01

    Structural incorporation of the actinide curium in the octahedral layer of the trioctahedral Mg-rich smectite hectorite was studied using time-resolved laser fluorescence spectroscopy. Organo-hectorite nanoparticles were synthesized at 90 °C in the presence of Cm(III). Within 120 h, hectorite particles were formed. Time-resolved laser fluorescence spectroscopy was used to identify Cm(III) species during various synthesis steps and to characterize the structural incorporation mechanism. The formation of a Cm-containing Mg hydroxide precursor and the reaction with aqueous silica in a pH range of 9-10 to form TOT layers were identified to be key steps for trivalent actinide incorporation in hectorite via coprecipitation.

  4. Dispersion of TiO2 Nanoparticle Agglomerates by Pseudomonas aeruginosa? †

    PubMed Central

    Horst, Allison M.; Neal, Andrea C.; Mielke, Randall E.; Sislian, Patrick R.; Suh, Won Hyuk; Mädler, Lutz; Stucky, Galen D.; Holden, Patricia A.

    2010-01-01

    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 TiO2 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 TiO2 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-TiO2 biosorption. High-magnification scanning electron micrographs showed that P. aeruginosa dispersed TiO2 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 TiO2 nanoparticle agglomerates. PMID:20851981

  5. Nanoparticles synthesized from soy protein: preparation, characterization, and application for nutraceutical encapsulation.

    PubMed

    Teng, Zi; Luo, Yangchao; Wang, Qin

    2012-03-14

    Nanoparticles were synthesized from soy protein, one of the most abundant and widely utilized plant proteins, for nutraceutical and drug encapsulation. The preparation process consisted of dispersion, desolvation, drug incorporation, cross-linking, and evaporation. The role of each procedure in the formation of nanoparticles was systematically investigated by means of particle size, size distribution, and zeta potential as well as morphology observation. Curcumin as a model drug was encapsulated successfully into the nanoparticles, evidenced by Fourier transform infrared spectroscopy and X-ray diffraction patterns. The average size of the curcumin-loaded nanoparticles was 220.1 to 286.7 nm, and their zeta potential was around -36 mV. The highest encapsulation efficiency and loading efficiency achieved were 97.2% and 2.7%, respectively. The release of curcumin in phosphate buffer saline followed a biphasic pattern. Possible mechanisms of the formation of soy protein nanoparticles as well as the incorporation of curcumin were discussed based on the data obtained from this study. PMID:22352467

  6. Thermally conductive of nanofluid from surfactant doped polyaniline nanoparticle and deep eutectic ionic liquid

    NASA Astrophysics Data System (ADS)

    Siong, Chew Tze; Daik, Rusli; Hamid, Muhammad Azmi Abdul

    2014-09-01

    Nanofluid is a colloidal suspension of nano-size particles in a fluid. Spherical shape dodecylbenzenesulfonic acid doped polyaniline (DBSA-PANI) nanoparticles were synthesized via reverse micellar polymerization in isooctane with average size of 50 nm- 60 nm. The aim of study is to explore the possibility of using deep eutectic ionic liquid (DES) as a new base fluid in heat transfer application. DES was prepared by heating up choline chloride and urea with stirring. DES based nanofluids containing DBSA-PANI nanoparticles were prepared using two-step method. Thermal conductivity of nanofluids was measured using KD2 Pro Thermal Properties Analyzer. When incorporated with DBSA-PANI nanoparticles, DES with water was found to exhibit a bigger increase in thermal conductivity compared to that of the pure DES. The thermal conductivity of DES with water was increased by 4.67% when incorporated with 0.2 wt% of DBSA-PANI nanoparticles at 50°C. The enhancement in thermal conductivity of DES based nanofluids is possibly related to Brownian motion of nanoparticles as well as micro-convection of base fluids and also interaction between dopants and DES ions.

  7. Theoretical study of the interparticle interaction of nanoparticles randomly dispersed on a substrate

    NASA Astrophysics Data System (ADS)

    Horikoshi, S.; Kato, T.

    2015-01-01

    Metal nanoparticles exhibit the phenomenon of localized surface plasmon resonance (LSPR) due to the collective oscillation of their conduction electrons, which is induced by external electromagnetic radiation. The finite-differential time-domain (FDTD) method is widely used as an electromagnetic field analysis tool for nanoparticles. Although the influence of interparticle interactions is taken into consideration in the FDTD calculation for the plural particles configuration, the FDTD calculation of a random configuration is very difficult, particularly in the case of non-spherical particles. In this study, a theoretical calculation method incorporating interparticle interactions on a substrate with various particle shapes and sizes on a subwavelength scale is developed. The interparticle interaction is incorporated following FDTD calculation with an isolated single particle. This is explained systematically using a signal flow graph. Moreover, the mirror image effect of the substrate and the retardation effect are also taken into account in this method. The validity of this method is verified by calculations for simple arrangements of nanoparticles. In addition, it is confirmed that the method can improve the accuracy of predicted experimental results for Au nanoparticles prepared by the sputtering method, in terms of the plasmon peak wavelength. This method may enable the design of LSPR devices by controlling nanoparticle characteristics, such as the size, shape, and distribution density.

  8. Luminescence of TiO 2:Pr nanoparticles incorporated in silica aerogel

    Microsoft Academic Search

    A. Amlouk; L. El Mir; S. Kraiem; M. Saadoun; S. Alaya; A. C. Pierre

    2008-01-01

    The photoluminescence of praseodymium ions in SiO2\\/TiO2 glasses elaborated by the sol–gel method was reported. It is shown that Pr ions were embedded in TiO2 nanocrystals (tetragonal, rutile) surrounded by a SiO2 glass matrix. Photoluminescence (PL) and photoluminescence excitation (PLE) spectra revealed the presence of energy transfer between the host matrix states and Pr3+ ions. X-ray diffraction (XRD) spectra, specific

  9. Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis

    NASA Astrophysics Data System (ADS)

    Jin, Zhao

    Noble metal nanoparticles/nanocrystals have attracted much attention as catalysts due to their unique characteristics, including high surface areas and well-controlled facets, which are not often possessed by their bulk counterparts. To avoid the loss of their catalytic activities brought about by their size and shape changes during catalytic reactions, noble metal nanoparticles/nanocrystals are usually dispersed and supported finely on solid oxide supports to prevent agglomeration, nanoparticle growth, and therefore the decrease in the total surface area. Moreover, metal oxide supports can also play important roles in catalytic reactions through the synergistic interactions with loaded metal nanoparticles/nanocrystals. In this thesis, I use ultrasonic aerosol spray to produce hybrid microspheres that are composed of noble metal nanoparticles/nanocrystals embedded in mesoporous metal oxide matrices. The mesoporous metal oxide structure allows for the fast diffusion of reactants and products as well as confining and supporting noble metal nanoparticles. I will first describe my studies on noble metal-loaded mesoporous oxide microspheres as catalysts. Three types of noble metals (Au, Pt, Pd) and three types of metal oxide substrates (TiO2, ZrO2, Al 2O3) were selected, because they are widely used for practical catalytic applications involved in environmental cleaning, pollution control, petrochemical, and pharmaceutical syntheses. By considering every possible combination of the noble metals and oxide substrates, nine types of catalyst samples were produced. I characterized the structures of these catalysts, including their sizes, morphologies, crystallinity, and porosities, and their catalytic performances by using a representative reduction reaction from nitrobenzene to aminobenzene. Comparison of the catalytic results reveals the effects of the different noble metals, their incorporation amounts, and oxide substrates on the catalytic abilities. For this particular reaction, I found that Pd nanoparticles supported on mesoporous TiO2 exhibit the best catalytic performance. The demonstrated low-cost and high-productivity preparation method can be extended to other catalysts, which can contain various metals and oxide substrates and will have high potential for industrial applications. Our preparation method also provides a platform for the studies of the synergetic catalytic effects between different oxide substrates and metals. I further fabricated hollow mesoporous microspheres containing differently shaped noble metal nanocrystals. Hollow structures are strongly desired in many applications because of their high pore volumes, surface areas, and possible light-trapping effect. In my study, the hollow structures were obtained by simply dispersing polystyrene (PS) nanospheres into the precursor solution for aerosol spray. The PS spheres were removed by thermal calcination to produce hollow mesoporous microspheres. In my first study, the noble metal salts were dissolved in the precursor solutions, and the noble metal nanoparticles were obtained through thermal calcination. In this way, the size and shape of the metal nanoparticles cannot be well controlled. In my second study, I first grew noble metal nanocrystals and then incorporated them into the oxide supports. This preparation route allowed me to incorporate metal nanocrystals with controlled sizes, shapes, and compositions into the oxide matrices. The metal nanocrystals I used in this experiment included Pd nanocubes, Au nanorods, and Au core--Pd shell nanorods. These nanocrystals were functionalized with thiol-terminated methoxypoly(ethylene glycol) . The surface functionalization allowed them to adsorb on the PS spheres. After thermal calcination, the noble metal nanocrystals were left inside and adsorbed on the inner surface of the hollow mesoporous metal oxide microspheres. I investigated the catalytic activities of the Pd nanocube-embedded hollow mesoporous TiO2 and ZrO2 microspheres for the reduction of 4-nitrophenol to 4-aminophenol. I also examined the recycla

  10. Nanoparticles forNanoparticles for Pharmaceutical ApplicationsPharmaceutical Applications

    E-print Network

    Lightsey, Glenn

    1 Nanoparticles forNanoparticles for Pharmaceutical ApplicationsPharmaceutical Applications Robert--soluble drugssoluble drugs 40% of pharmaceutical drugs in development40% of pharmaceutical drugs in development engineering 4 Solution: delivery system for PWS drugsSolution: delivery system for PWS drugs Melt extrusion

  11. 43 CFR 46.110 - Incorporating consensus-based management.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Incorporating consensus-based management. 46.110 Section 46...Enhancement of Environmental Quality § 46.110 Incorporating consensus-based management. (a) Consensus-based management incorporates direct...

  12. 43 CFR 46.110 - Incorporating consensus-based management.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Incorporating consensus-based management. 46.110 Section 46...Enhancement of Environmental Quality § 46.110 Incorporating consensus-based management. (a) Consensus-based management incorporates direct...

  13. 43 CFR 46.110 - Incorporating consensus-based management.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Incorporating consensus-based management. 46.110 Section 46...Enhancement of Environmental Quality § 46.110 Incorporating consensus-based management. (a) Consensus-based management incorporates direct...

  14. 43 CFR 46.110 - Incorporating consensus-based management.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Incorporating consensus-based management. 46.110 Section 46...Enhancement of Environmental Quality § 46.110 Incorporating consensus-based management. (a) Consensus-based management incorporates direct...

  15. 43 CFR 46.110 - Incorporating consensus-based management.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Incorporating consensus-based management. 46.110 Section 46...Enhancement of Environmental Quality § 46.110 Incorporating consensus-based management. (a) Consensus-based management incorporates direct...

  16. Shockwave Spectroscopy of Nanoparticles

    NASA Astrophysics Data System (ADS)

    Merkle, Maxwell Graham

    This dissertation examines the effects of laser-generated shockwaves on colloidally prepared nanocrystals. Their microscopic structure is first examined utilizing gold nanoparticles. The properties under scrutiny in the first study are used to then initiate a polymorphic phase transition in CdSe quantum dots. In the final study, hollow CdS particles are used to show the utility of nanoparticles as possible energy attenuation materials. In gold nanoparticles it is shown, for the first time, a direct observation of the effect of density increase on the optical properties of gold nanoparticles. The splitting of the plasmon resonance into two distinct peaks illustrates the result of a uniaxial compression characteristic of a shock wave. The behavior of CdSe nanocrystals shocked to stresses of 2--3.75 GPa has been studied. Above 3 GPa a near-complete disappearance of the first excitonic feature and broadening of the low-energy absorption edge were observed, consistent with a wurtzite to rocksalt structural transformation. The transformation pressure is reduced relative to hydrostatic compression in a diamond anvil cell. Also, the rate of the phase transition increases. These effects are attributed to shock induced shear stress along the reaction coordinate. The especially rapid rate observed for a 3.75 GPa shock suggests multiple nucleation events per particle. Hollow CdS nanospheres have been fractured under the action of laser-induced shock waves. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have been used to image the recovered fragmented particles. Additionally, time-resolved measurements of the transmission of the shock wave through a polymer layer containing hollow nanospheres have been carried out. The hollow nanospheres can attenuate the transmitted shock above a threshold stress. At the highest shock stresses measured, the shock attenuation layer acts as a composite shocked above its elastic limit. To these ends we show that nanoparticles are useful in studying and altering the properties of shockwaves. Shockwaves are also shown to be useful in high time-resolution studies of the morphological processes in solids, using nanocrystals as the archetypical, single-domain sample.

  17. Synthesis and characterization of iron based nanoparticles for novel applications

    NASA Astrophysics Data System (ADS)

    Khurshid, Hafsa

    The work in this thesis has been focused on the fabrication and characterization of iron based nanoparticles with controlled size and morphology with the aim: (i) to investigate their properties for potential applications in MICR toners and biomedical field and (ii) to study finite size effects on the magnetic properties of the nanoparticles. For the biomedical applications, core/shell structured iron/iron-oxide and hollow shell nanoparticles were synthesized by thermal decomposition of iron organometallic compounds [Fe(CO)5] at high temperature. Core/shell structured iron/iron-oxide nanoparticles have been prepared in the presence of oleic acid and oleylamine. Particle size and composition was controlled by varying the reaction parameters during synthesis. The as-made particles are hydrophobic and not dispersible in water. Water dispersibility was achieved by ligand exchange a with double hydrophilic diblock copolymer. Relaxometery measurements of the transverse relaxation time T2 of the nanoparticles solution at 3 Tesla confirm that the core/shell nanoparticles are an excellent MRI contrast agent using T2 weighted imaging sequences. In comparison to conventionally used iron oxide nanoparticles, iron/iron-oxide core/shell nanoparticles offer four times stronger T2 shortening effect at comparable core size due to their higher magnetization. The magnetic properties were studied as a function of particle size, composition and morphology. Hollow nanostructures are composed of randomly oriented grains arranged together to make a shell layer and make an interesting class of materials. The hollow morphology can be used as an extra degree of freedom to control the magnetic properties. Owing to their hollow morphology, they can be used for the targeted drug delivery applications by filling the drug inside their cavity. For the magnetic toners applications, particles were synthesized by chemically reducing iron salt using sodium borohydride and then coated with polyethylene glycol. Parameters such as the reactant concentrations and their flow rate were varied to study the effect of particle size, structure and crystallinity on the magnetic nanoparticles. Many different hydrophilic surfactants and polymers electrolytes were investigated for the particles' stability in water. PSSNa was found to be the best coating agent among all the other investigated polymer and surfactants for particles stability in water. Particles have an average size of 50 nm and magnetization above 150 emu/g. It is anticipated that owing to their high saturation magnetization and magneto crystalline anisotropy, the incorporations of PSSNa coated nanoparticles into the MICR toner can reduce the pigment loading and hence optimize the toner quality. The magnetic properties were studied as a function of particle size, composition and morphology. The saturation magnetization and coercivity was found to be strongly dependent on the particle size and morphology. The estimated effective anisotropy of the particles was found to be much higher than their bulk values because of their morphology and finite size effects. Core/shell particles below an average size of 12 nm display superparamagnetism and exchange bias phenomenon. The hollow morphology can be used as an extra degree of freedom to control magnetic properties. The enormously large number of pinned spins at the inner and outer surface and at the interface between the grain boundaries in hollow nanoparticles, gives rise to a very large value of effective anisotropy in these nanoparticles and measured hyteresis loops are minor loops. The surface spin disorder contribution to magnetic behavior is strongly influenced by the cooling field magnitude.

  18. Antimicrobial Properties of Silver Nanoparticles

    NSDL National Science Digital Library

    Kouadio, Carrie

    This module provides students the opportunity to "explore silver nanoparticles and their effectiveness against bacterial growth in hands-on laboratory activities." Students first make silver nanoparticles and then use them in an experiment they design. This lesson will require two or more class periods and is aimed at secondary students.The document is available to download in PDF file format.

  19. Credible intervals for nanoparticle characteristics

    NASA Astrophysics Data System (ADS)

    Charnigo, Richard; Francoeur, Mathieu; Kenkel, Patrick; Mengüç, M. Pinar; Hall, Benjamin; Srinivasan, Cidambi

    2012-01-01

    Solving the inverse problem of nanoparticle characterization has the potential to advance science and benefit society. While considerable progress has been made within a framework based on the scattering of surface plasmon-polaritons, an aspect not heretofore considered is the quantification of uncertainty in the estimation of a nanoparticle characteristic. Therefore, the present article offers a technique by which an investigator may augment an estimate of a nanoparticle characteristic with a companion “credible interval”. Analogous to the familiar confidence interval but arising from within the Bayesian statistical paradigm, a credible interval allows the investigator to make a statement such as “the nanoparticle diameter lies between 36 and 48 nm with 95% probability” instead of merely “the nanoparticle diameter is estimated to be 42 nm”. Our technique may even be applied outside of the surface plasmon-polariton scattering framework, as long as the investigator specifies his/her prior beliefs about the nanoparticle characteristic and indicates which potential outcomes are likely or unlikely in whatever experiment he/she designs to estimate the nanoparticle characteristic. Two numerical studies illustrate the implementation and performance of our technique in constructing ranges of likely values for nanoparticle diameters and agglomeration levels, respectively.

  20. Resveratrol in Solid Lipid Nanoparticles

    Microsoft Academic Search

    Maria Eugenia Carlotti; Simona Sapino; Elena Ugazio; Marina Gallarate; Silvia Morel

    2011-01-01

    This report investigates the possibility of producing solid lipid nanoparticles as protective vehicle of resveratrol, an antioxidant characterised by a fast trans-cis isomerisation. SLN aqueous dispersions were produced by hot melt homogenisation technique and characterised. It was found that the presence of tetradecyl-?-cyclodextrin in SLN formulation induced an improvement of nanoparticle characteristics. Moreover a significant reduction in resveratrol photodegradation was

  1. Role of Nanoparticles in Photocatalysis

    Microsoft Academic Search

    D. Beydoun; R. Amal; G. Low; S. McEvoy

    1999-01-01

    The aim of this review paper is to give an overview of the development and implications of nanotechnology in photocatalysis. The topics covered include a detailed look at the unique properties of nanoparticles and their relation to photocatalytic properties. Current applications of and research into the use of nanoparticles as photocatalysts has also been reviewed. Also covered is the utilization

  2. 49 CFR 572.180 - Incorporated materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Drawing No. 175-3500, Arm Assembly, Left; (vi) Drawing No. 175-3800, Arm...Drawing No. 175-7000-1, Leg Assembly—left; (xii) Drawing No. 175-7000-2...Drawing No. 175-3500, Arm Assembly, Left, incorporated by reference in §§...

  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. Incorporating user search behaviour into relevance feedback

    Microsoft Academic Search

    Ian Ruthven; Mounia Lalmas; Keith van Rijsbergen

    2002-01-01

    In this paper we present five user experiments on incorporating behavioural information into the relevance feedback process. In particular we concentrate on ranking terms for query expansion and selecting new terms to add to the user's query. Our experiments are an attempt to widen the evidence used for relevance feedback from simply the relevant documents to include information on how

  5. Incorporating the Aesthetic Dimension into Pedagogy

    ERIC Educational Resources Information Center

    Webster, R. Scott; Wolfe, Melissa

    2013-01-01

    This paper reports on a case study that was undertaken to discover not only the belief and intent behind the everyday opportunities that four exemplary teachers offered their high performing students but what activities they incorporated into their everyday lessons in an attempt to make sense of how aesthetic experiences may enhance learning. The…

  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. 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…

  8. Manganese incorporation into ferroelectric lead titanate

    Microsoft Academic Search

    Stanislav Stoupin

    2007-01-01

    Substitution with 3d magnetic transition elements in ABO 3 ferroelectric perovskite host media is widely utilized to produce relaxor ferroelectrics. Many resulting solid solutions exhibit magnetoelectric properties affected by concentration levels of the introduced magnetic ions. For conventional material preparation techniques such as firing of mechanically mixed oxides, incorporation is often limited by 5 mol% concentration level. Doping at higher

  9. 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.

  10. Incorporating Yield Enhancement into the Floorplanning Process

    E-print Network

    Koren, Israel

    Incorporating Yield Enhancement into the Floorplanning Process Israel Koren, Fellow, IEEE the yield of the chip as well. Consequently, it becomes desirable to consider the expected yield the two seemingly unrelated, and often conflicting, objectives of yield enhancement and routing complexity

  11. Passive suspensions incorporating inerters for railway vehicles

    Microsoft Academic Search

    Jason Zheng Jiang; Alejandra Z. Matamoros-Sanchez; Roger M. Goodall; Malcolm C. Smith

    2012-01-01

    This paper investigates the possibility of improving the performance of railway vehicle suspensions by incorporating a newly developed mechanical device known as the inerter. A comparative study of several low-complexity passive suspension layouts is made. Improved performance for the lateral and vertical ride comfort, as well as lateral body movement when curving are demonstrated in comparison with the conventional suspension

  12. THE LONDON MATHEMATICAL SOCIETY CHARTER OF INCORPORATION

    E-print Network

    Mottram, Nigel

    1 THE LONDON MATHEMATICAL SOCIETY CHARTER OF INCORPORATION GRANTED 3rd OF AUGUST 1965 ELIZABETH THESE PRESENTS SHALL COME, GREETING! WHEREAS a Petition has been presented unto Us by the President of the London to the London Mathematical Society with the object among others of acquiring and taking over the properties

  13. Incorporating Engineering Applications into Calculus Instruction 1

    Microsoft Academic Search

    Guoqing Tang; Bala Ram; Milin Shah

    The purpose of this paper is to present two multimedia modules in the areas of differential calculus, industrial engineering and industrial management as well as preliminary results on incorporating one of the modules in calculus instruction. These two modules are developed through a collaboration between the mathematics and industrial engineering departments at North Carolina A&T State University under the NSF

  14. 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…

  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. 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...

  17. 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…

  18. Beyond Classroom Boundaries: Incorporating Context in Teaching.

    ERIC Educational Resources Information Center

    CATESOL Journal, 1994

    1994-01-01

    This English-as-a-Second-Language (ESL) journal periodically devotes entire issues to specific issues. The theme of this issue is "Incorporating Context in Teaching." Articles include: "Learning Beyond the Classroom: Developing the Community Connection" (Tim Beard); "Smiling through the Turbulence: The Flight Attendant Syndrome and Other Issues of…

  19. Cognitive Social Simulation Incorporating Cognitive Architectures

    E-print Network

    Varela, Carlos

    Cognitive Social Simulation Incorporating Cognitive Architectures Ron Sun June 15, 2007 Abstract computing, can benefit from incorporat- ing cognitive architectures, as they provide a realistic basis is a domain-generic computational cognitive model that may be used for a broad multiple-domain analysis

  20. The antimicrobial properties of light-activated polymers containing methylene blue and gold nanoparticles.

    PubMed

    Perni, Stefano; Piccirillo, Clara; Pratten, Jonathan; Prokopovich, Polina; Chrzanowski, Wojciech; Parkin, Ivan P; Wilson, Michael

    2009-01-01

    We report the formation of polysiloxane polymers containing embedded methylene blue and gold nanoparticles incorporated by a swell-encapsulation-shrink method. These polymers show significant antimicrobial activity against methicillin-resistant Staphylococcus aureus and Escherichia coli with up to a 3.5 log(10) reduction in the viable count when exposed for 5 min to light from a low power 660 nm laser. The bacterial kill is due to the light-induced production of singlet oxygen and other reactive oxygen species by the methylene blue. Interestingly, the presence of 2 nm gold nanoparticles significantly enhanced the ability of the methylene blue to kill bacteria. PMID:18838166

  1. Electrochemical detection of commercial silver nanoparticles: identification, sizing and detection in environmental media

    NASA Astrophysics Data System (ADS)

    Stuart, E. J. E.; Tschulik, K.; Omanovi?, D.; Cullen, J. T.; Jurkschat, K.; Crossley, A.; Compton, R. G.

    2013-11-01

    The electrochemistry of silver nanoparticles contained in a consumer product has been studied. The redox properties of silver particles in a commercially available disinfectant cleaning spray were investigated via cyclic voltammetry before particle-impact voltammetry was used to detect single particles in both a typical aqueous electrolyte and authentic seawater media. We show that particle-impact voltammetry is a promising method for the detection of nanoparticles that have leached into the environment from consumer products, which is an important development for the determination of risks associated with the incorporation of nanotechnology into everyday products.

  2. Micropatterning of Ag and Au nanoparticles by microcontact printing and block copolymer micelles.

    PubMed

    Xu, Peng; Ji, Xin; Abetz, Volker; Jiang, Shimei

    2011-02-01

    Micropatterns of gold and silver nanoparticles were successfully obtained by combining microcontact printing and poly(2-vinylpyridine)-block-poly(cyclohexyl metharylate) (P2VP-b-PCHMA) diblock copolymer micelles with metal precursors. The metal ions were incorporated into poly(2-vinylpyridine) blocks and located into the core area of micelles. Then the metal-loaded micellar solutions were used as inks which were spin coated as thin layers onto polydimethylsiloxane stamps and transferred onto the substrates by stamping. Different morphologies of micellar aggregates were formed on the substrates depending on the stamp morphologies, and single layers of nanoparticles in the micropattern were obtained by the reducing process. PMID:21456150

  3. Nanostructured silicon thin films deposited by PECVD in the presence of silicon nanoparticles

    SciTech Connect

    Viera, G.; Cabarrocas, P.R.; Hamma, S.; Sharma, S.N.; Costa, J.; Bertran, E.

    1997-07-01

    Nanostructured silicon thin films have been deposited by plasma enhanced chemical vapor deposition at low substrate temperature (100 C) in the presence of silicon nanoparticles. The nanostructure of the films was revealed by transmission electron microscopy, Raman spectroscopy and X-ray diffraction, which showed ordered silicon domains (1--2 nm) embedded in an amorphous silicon matrix. These ordered domains are due to the particles created in the discharge that contribute to the film growth. One consequence of the incorporation of nanoparticles is the accelerated crystallization of the nanostructured silicon thin films when compared to standard a-Si:H, as shown by the electrical characterization during the annealing.

  4. Gold-Nanoparticle-Enhanced Cancer Photothermal Therapy

    Microsoft Academic Search

    Jing-Liang Li; Min Gu

    2010-01-01

    In this paper, progress on the gold-nanoparticle-enhanced photothermal therapy is reviewed. Size- and shape-dependent optical absorption of gold nanoparticles, the effects of various parameters on the therapeutic efficiency, and the mechanisms of gold-nanoparticle-assisted cancer therapy are discussed. Future research directions of gold-nanoparticle-assisted cancer photothermal therapy are also suggested.

  5. Molecular imaging and sensing using plasmonic nanoparticles

    Microsoft Academic Search

    Matthew James Crow

    2010-01-01

    Noble metal nanoparticles exhibit unique optical properties that are beneficial to a variety of applications, including molecular imaging. The large scattering cross sections of nanoparticles provide high contrast necessary for biomarkers. Unlike alternative contrast agents, nanoparticles provide refractive index sensitivity revealing information regarding the local cellular environment. Altering the shape and composition of the nanoparticle shifts the peak resonant wavelength

  6. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  7. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  8. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  9. 49 CFR 537.10 - Incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AUTOMOTIVE FUEL ECONOMY REPORTS § 537.10 Incorporation by reference. (a) A manufacturer may incorporate by...

  10. Functionalized nanoparticles for sensor applications.

    SciTech Connect

    Simonson, Robert Joseph; Childs, Kenton David; Howell, Stephen Wayne; Dirk, Shawn M.; Wheeler, David Roger

    2005-09-01

    We will describe our work on functionalized arrays of nanoparticles crosslinked with short conducting molecules that contain sensing functionalities. These bridging ligands modulate their conductivity based on their interaction with analytes. This functionalized nanoparticles organic ligand composite material once it is assembled between nanogaps electrodes will provide nanosized sensors that can be easily interrogated. These nanogap sensors will be engineered so that they can be fabricated into arrays of different sensor elements. This project consists of a number of different requirements that must be met in order to enable the use of functionalized nanoparticles for sensor applications. The first requirement is the appropriately functionalized nanoparticle. The second is a method to assemble the particles. The third requirement is the generation of a nanogap to contain the nanoparticles. The successes in each of these areas will be discussed as will the sensing behavior of the final films.

  11. Silica-based mesoporous nanoparticles for controlled drug delivery

    PubMed Central

    Kwon, Sooyeon; Singh, Rajendra K; Perez, Roman A; Abou Neel, Ensanya A

    2013-01-01

    Drug molecules with lack of specificity and solubility lead patients to take high doses of the drug to achieve sufficient therapeutic effects. This is a leading cause of adverse drug reactions, particularly for drugs with narrow therapeutic window or cytotoxic chemotherapeutics. To address these problems, there are various functional biocompatible drug carriers available in the market, which can deliver therapeutic agents to the target site in a controlled manner. Among the carriers developed thus far, mesoporous materials emerged as a promising candidate that can deliver a variety of drug molecules in a controllable and sustainable manner. In particular, mesoporous silica nanoparticles are widely used as a delivery reagent because silica possesses favourable chemical properties, thermal stability and biocompatibility. Currently, sol-gel-derived mesoporous silica nanoparticles in soft conditions are of main interest due to simplicity in production and modification and the capacity to maintain function of bioactive agents. The unique mesoporous structure of silica facilitates effective loading of drugs and their subsequent controlled release. The properties of mesopores, including pore size and porosity as well as the surface properties, can be altered depending on additives used to fabricate mesoporous silica nanoparticles. Active surface enables functionalisation to modify surface properties and link therapeutic molecules. The tuneable mesopore structure and modifiable surface of mesoporous silica nanoparticle allow incorporation of various classes of drug molecules and controlled delivery to the target sites. This review aims to present the state of knowledge of currently available drug delivery system and identify properties of an ideal drug carrier for specific application, focusing on mesoporous silica nanoparticles. PMID:24020012

  12. Antibiofilm Properties of Silver and Gold Incorporated PU, PCLm, PC and PMMA Nanocomposites under Two Shear Conditions

    PubMed Central

    Sawant, Shilpa N.; Selvaraj, Veerapandian; Prabhawathi, Veluchamy; Doble, Mukesh

    2013-01-01

    Silver and gold nanoparticles (of average size ?20–27 nm) were incorporated in PU (Polyurethane), PCLm (Polycaprolactam), PC (polycarbonate) and PMMA (Polymethylmethaacrylate) by swelling and casting methods under ambient conditions. In the latter method the nanoparticle would be present not only on the surface, but also inside the polymer. These nanoparticles were prepared initially by using a cosolvent, THF. PU and PCLm were dissolved and swollen with THF. PC and PMMA were dissolved in CHCl3 and here the cosolvent, THF, acted as an intermediate between water and CHCl3. FTIR indicated that the interaction between the polymer and the nanoparticle was through the functional group in the polymer. The formation of E.coli biofilm on these nanocomposites under low (in a Drip flow biofilm reactor) and high shear (in a Shaker) conditions indicated that the biofilm growth was higher (twice) in the former than in the latter (ratio of shear force?=?15). A positive correlation between the contact angle (of the virgin surface) and the number of colonies, carbohydrate and protein attached on it were observed. Ag nanocomposites exhibited better antibiofilm properties than Au. Bacterial attachment was highest on PC and least on PU nanocomposite. Casting method appeared to be better than swelling method in reducing the attachment (by a factor of 2). Composites reduced growth of organisms by six orders of magnitude, and protein and carbohydrate by 2–5 times. This study indicates that these nanocomposites may be suitable for implant applications. PMID:23675476

  13. Bubble template synthesis of hollow gold nanoparticles and their applications as theranostic agents

    NASA Astrophysics Data System (ADS)

    Huang, Chienwen

    Hollow gold nanoparticle with a sub-30nm polycrystalline shell and a 50 nm hollow core has been successfully synthesized through the reduction of sodium gold sulfite by electrochemically evolved hydrogen. Such hollow gold nanoparticles exhibit unique plasmonic properties. They strongly scatter and absorb near infrared light. In this thesis we seek to understand the formation mechanism of hollow gold nanoparticles in this new synthesis process and their plasmonic properties. Also, we explore their biomedical applications as theranostic agents (therapeutic and diagnostic imaging). A lithographically patterned electrode consisting of Ag stripes on a glass substrate was used to investigate the formation process of hollow gold nanoparticles. Ag stripes served as working electrode for electrochemically evolution of hydrogen, and adjacent glass areas provided supporting surface for hydrogen nanobubbles nucleation and growth. Hydrogen nanobubbles served as both templates and reducing agents to trigger the autocatalytic disproportionation reaction of sodium gold sulfite. The effects of applied potential and the additives in the electrolyte have been studied. It has been found that the size and size distribution of hollow gold nanoparticle are directly relative to the applied potential, i.e. the hydrogen evolution rate. It has also been found the addition of Ni2+ ions can greatly improve the size distribution of hollow gold nanoparticles that can be contributed to that the newly electrodeposited nickel metal can enhance the hydrogen evolution efficiency. Another additive, ethylenediamine (EDA) can suppress the autocatalytic reaction of gold sulfite to increase the stability of sodium gold sulfite electrolyte. To capture such electrochemically evolved hydrogen nanobubbles, and subsequently to generate hollow gold nanoparticles in large numbers, alumina membranes were placed on the top of the working electrode. Anodic alumina membrane consists of ~200 nm pores, which provides a large surface area for the formation of hydrogen nanobubbles. By this approach, the electroless reaction can be easily separated from the electrodeposition process, and hollow gold nanoparticles can be easily collected. Synthesized hollow gold nanoparticles exhibit unique plasmonic properties; the surface plasmon resonance (SPR) lies in the near infrared region (NIR). This is very different from the solid spherical gold nanoparticles. Three-dimensional finite difference time domain (FDTD) simulation was employed to study the plasmonic properties of hollow gold nanoparticles. It has been found that the red-shifts of SPR peaks are mainly caused by their surface roughness, and the hollow nature of these particles only plays a minor role. The surface roughness of hollow gold nanoparticles can be tuned by adjusting the pH of the electrolyte (from 6.0 to 7.0) by adding sodium sulfite. Different surface roughness (from smooth to very rough) can be readily obtained, and correspondingly, surface plasmon resonance (SPR) peaks red-shift from ~600 nm to ~750 nm. Using hollow gold nanoparticles as multifunctional agents for biomedical applications have been explored. Two kinds of agents have been constructed. It has been demonstrated that pegylated Raman dye encoded hollow gold nanoparticles, terms as Raman nanotags, can serve as both diagnostic imaging agents and photothermal therapy agents. When illuminated by near infrared light, the enhanced Raman signal makes the hollow gold nanoparticles to become optically detectable for biomedical imaging, and absorbed light rapidly heat up the hollow gold nanoparticles which can be used to photothermal ablation therapy. The cytotoxicity evaluation using [3H] thymidine incorporation method has shown non-toxicity of the Raman nanotags. The photothermal effects of hollow gold nanoparticles have been examined by two methods: (1) by embedding hollow gold nanoparticles in tissue-like phantom environment; (2) by recording infrared images as temperature increase. The results show that hollow gold nanoparticles are capable to generate suf

  14. Galactosylated Albumin Nanoparticles of Simvastatin

    PubMed Central

    Ganesh, Kumar; Archana, Dhyani; Preeti, Kothiyal

    2015-01-01

    The present study was an attempt to develop galactosylated albumin nanoparticles of Simvastatin for treatment of hypercholesterolemia. By developing the galactosylated nanoparticulated delivery, the required action of the drug at the target site at the liver can be provided. The advantage of targeting helps to reduce the systemic side effects that may occur due to the distribution of the drug to the other organs and thus helps in maintaining the required concentration of drug at the desired site. The galacotsylated albumin nanoparticles were prepared for the selective delivery of a Simvastatin to the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) the rate-limiting enzyme in the pathway of cholesterol biosynthesis that is particularly presents on hepatocytes. The asialoglycoprotein receptor (ASGP-R) which is particularly presents on mammalian hepatocytes can be utilize for active targeting by using its natural and synthetic ligands. By utilizing this receptors can provides a unique means for the development of liver-specific carriers, such as liposomes, recombinant lipoproteins, and polymers for drug or gene delivery to the liver, especially to hepatocytes. These receptors recognize the ligands with terminal galactose or N-acetylgalactosamine residues, and endocytose the ligands for an intracellular degradation process. The albumin nanoparticles (NPs) were prepared by using desolvation method and efficiently conjugated with galactose. Various parameters such as particle size, zeta potential, percentage entrapment efficiency and drug loading efficiency, percentage yield, in-vitro drug release were determined. The size of nanoparticles (both plain and coated NPs) was 200 and 250 nm. The zeta potential of plain nanoparticles was -3.61 and that of galactose-coated nanoparticles was 64.1. The maximum drug content was in between 79.98% to 79.8 % respectively in plain, and galactose coated nanoparticles while the maximum entrapment efficiency was 70.10% and 71.03% in plain and coated nanoparticles. It was found that coating of nanoparticles increases the size of nanoparticles.

  15. Functionalized Magnetic Nanoparticles as an In Vivo Delivery System

    NASA Astrophysics Data System (ADS)

    Taira, Shu; Moritake, Shinji; Hatanaka, Takahiro; Ichiyanagi, Yuko; Setou, Mitsutoshi

    We developed extremely small functionalized magnetic nanoparticles (MNPs) for use as an in vivo delivery system for pharmaceuticals and biomolecules. We functionalized the MNPs (d = 3 nm) by silanization of amino groups on the particles with (3-aminopropyl)triethoxysilane for subsequent cross-linking with pharmaceuticals and biomolecules. The MNPs were successfully introduced into living cells without any further modification, such as the use of cationic residues, to enhance endocytic internalization. The particles could be incorporated into the subcutaneous tissue of a mouse’s ear through the skin of the ear and could be localized by application of an external magnetic field.

  16. Innovative composite films of chitosan, methylcellulose, and nanoparticles.

    PubMed

    Mura, Stefania; Corrias, Francesco; Stara, Giuseppe; Piccinini, Massimo; Secchi, Nicola; Marongiu, Daniela; Innocenzi, Plinio; Irudayaraj, Joseph; Greppi, Gian F

    2011-09-01

    Plastic is readily available and inexpensive, so it is becoming the main material for packaging. Unfortunately plastics do not biodegrade and, if reduced in small pieces, contaminate soil and waterways. In the present work, natural films composed of chitosan, methylcellulose, and silica (SiO(2)) nanoparticles (NPs) were developed as new packaging materials. The effect of the incorporation of NPs into the polymeric film matrix was evaluated. An excellent improvement of the mechanical properties was obtained for nanostructured films with a composition of CH:MC 50:50 and NPs 1% w/v that make these materials able to replace plastics and derivatives, reducing environmental pollution. PMID:21819401

  17. The Effect of Iron Oxide Magnetic Nanoparticles on Smooth Muscle Cells

    NASA Astrophysics Data System (ADS)

    Zhang, Song; Chen, Xiangjian; Gu, Chunrong; Zhang, Yu; Xu, Jindan; Bian, Zhiping; Yang, Di; Gu, Ning

    2009-01-01

    Recently, magnetic nanoparticles of iron oxide (Fe3O4, ?-Fe2O3) have shown an increasing number of applications in the field of biomedicine, but some questions have been raised about the potential impact of these nanoparticles on the environment and human health. In this work, the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) with the same crystal structure, magnetic properties, and size distribution was designed, prepared, and characterized by transmission electronic microscopy, powder X-ray diffraction, zeta potential analyzer, vibrating sample magnetometer, and Fourier transform Infrared spectroscopy. Then, we have investigated the effect of the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) on smooth muscle cells (SMCs). Cellular uptake of nanoparticles by SMC displays the dose, the incubation time and surface property dependent patterns. Through the thin section TEM images, we observe that DMSA-Fe2O3 is incorporated into the lysosome of SMCs. The magnetic nanoparticles have no inflammation impact, but decrease the viability of SMCs. The other questions about metabolism and other impacts will be the next subject of further studies.

  18. Preparation of folate-modified pullulan acetate nanoparticles for tumor-targeted drug delivery.

    PubMed

    Zhang, Hui-zhu; Li, Xue-min; Gao, Fu-ping; Liu, Ling-rong; Zhou, Zhi-min; Zhang, Qi-qing

    2010-01-01

    The purpose of this work was to develop a novel nano-carrier with targeting property to tumor. In this study, pullulan acetate (PA) was synthesized by the acetylation of pullulan to simplify the preparation technique of nanoparticles. Folic acid (FA) was conjugated to PA in order to improve the cancer-targeting activity. The products were characterized by proton nuclear magnetic resonance (¹H NMR) spectroscopy. Epirubicin-loaded nanoparticles were prepared by a solvent diffusion method. The loading efficiencies and EPI content increased with the amount of triethylamine (TEA) increasing in some degree. FPA nanoparticles could incorporate more epirubicin than PA nanoparticles. The folate-modified PA nanoparticles (FPA/EPI NPs) exhibited faster drug release than PA nanoparticles (PA/EPI NPs) in vitro. Confocal image analysis and flow cytometry test revealed that FPA/EPI NPs exhibited a greater extent of cellular uptake than PA/EPI NPs against KB cells over-expressing folate receptors on the surface. FPA/EPI NPs also showed higher cytotoxicity than PA/EPI NPs. The cytotoxic effect of FPA/EPI NPs to KB cells was inhibited by an excess amount of folic acid, suggesting that the binding and/or uptake were mediated by the folate receptor. PMID:22747075

  19. Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

    PubMed Central

    Notarianni, Marco; Rintoul, Llew; Motta, Nunzio

    2014-01-01

    Summary One-dimensional single crystal incorporating functional nanoparticles of other materials could be an interesting platform for various applications. We studied the encapsulation of nanoparticles into single-crystal ZnO nanorods by exploiting the crystal growth of ZnO in aqueous solution. Two types of nanodiamonds with mean diameters of 10 nm and 40 nm, respectively, and polymer nanobeads with size of 200 nm have been used to study the encapsulation process. It was found that by regrowing these ZnO nanorods with nanoparticles attached to their surfaces, a full encapsulation of nanoparticles into nanorods can be achieved. We demonstrate that our low-temperature aqueous solution growth of ZnO nanorods do not affect or cause degradation of the nanoparticles of either inorganic or organic materials. This new growth method opens the way to a plethora of applications combining the properties of single crystal host and encapsulated nanoparticles. We perform micro-photoluminescence measurement on a single ZnO nanorod containing luminescent nanodiamonds and the spectrum has a different shape from that of naked nanodiamonds, revealing the cavity effect of ZnO nanorod. PMID:24778975

  20. MR and fluorescence imaging of doxorubicin loaded nanoparticles using a novel in vivo model

    PubMed Central

    Erten, Ahmet; Wrasidlo, Wolf; Scadeng, Miriam; Esener, Sadik; Hoffman, Robert; Bouvet, Michael; Makale, Milan

    2010-01-01

    We report here the in vivo combined-modality imaging of multifunctional drug delivery nanoparticles. These dextran core-based stealth liposomal nanoparticles (nanosomes) contained doxorubicin, iron oxide for MRI contrast, and Bodipy for fluorescence. The particles were long-lived in vivo due to surface decoration with polyethylene glycol (PEG) and the incorporation of acetylated lipids which were UV cross-linked for physical stability. We developed a rodent dorsal skinfold window chamber which facilitated both MRI and non-destructive optical imaging of nanoparticle accumulation in the same tumors. Chamber tumors were genetically labeled with DsRed-2 that enabled the MR images, the red fluorescence of the tumor, and the blue fluorescence of the nanoparticles to be co-localized. The nanoparticle design and MR imaging developed with the window chamber were then extended to orthotopic pancreatic tumors expressing DsRed-2. The tumors were MR imaged using iron oxide-dextran liposomes and by fluorescence to demonstrate the deep imaging capability of these nanoparticles. PMID:20599526

  1. Multifunctional nanovehicles for combined 5-fluorouracil and gold nanoparticles based on the nanoprecipitation method.

    PubMed

    Karmi, Abeer; Husseini, Ghaleb A; Faroun, Maryam; Sowwan, Mukhles

    2011-06-01

    To facilitate the administration of combined 5-Fluorouracil (5-FU) and gold nanoparticles (for photothermal treatment purposes), we developed 5-FU-gold-poly(lactide-co-glycolic acid) (5-FU-Au-PLGA) nanovehicles, via the nanoprecipitation method. The gold nanoparticles were incorporated inside the 5-FU-PLGA carriers using a roller mixer. Morphological analysis using atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), indicated uniform, singly separated spherical nanoparticles (NPs). Drug content, recovery and entrapment in the NPs were approximated using UV-spectrophotometer data. Approximately 26% of nanoparticles were recovered after drying. The percentage of total drug content was about 30%, and the percentage of drug entrapment reached 57%. Electrostatic Force Microscopy images confirmed the presence of gold inside the drug-loaded nanoparticles. We speculate that the 20-nm gold particles were able to diffuse, after 12 hours of mixing (using the roller mixer), into the PLGA matrix through the 100-nm pores (observed by SEM) without affecting the integrity of the drug delivery vehicle. These synthesized nanoparticles show promise as multimodal vehicles in the delivery of chemotherapeutic agents. PMID:21770092

  2. Formulation and in vivo evaluation of effervescent inhalable carrier particles for pulmonary delivery of nanoparticles.

    PubMed

    Azarmi, Shirzad; Lobenberg, Raimar; Roa, Wilson H; Tai, Shusheng; Finlay, W H

    2008-09-01

    The purpose of this study was to evaluate the safety of a new inhalable effervescent carrier preparation containing model nanoparticles. Spray-freeze drying was used to prepare inhalable powders containing butylcyanoacrylate nanoparticles. The particle size of the nanoparticles before incorporation into the effervescent carrier and after dissolving the carrier powder was measured using laser light scattering. The particle size distribution of the effervescent carrier aerosol particles was measured using a cascade impactor. The prepared powder was tested in vivo using five Balb/c nude mice. The animals were treated with 1 mg of inhalable powder every week for 4 weeks. The body weight and morbidity score of the mice were observed over an 8-week period. The effervescent activity of the inhalable nanoparticle powder was observed when the powder was exposed to humidity. The particle size of the nanoparticles did not change significantly after spray-freeze drying. The mass median aerodynamic diameter (MMAD) of the prepared powder was 4.80 +/- 2.12 microm, which is suitable for lung delivery. The animals that were treated with effervescent powder tolerated the administration without any changes in their morbidity scores. Our pilot study demonstrates that pulmonary nanoparticle delivery via effervescent carrier particles appears safe in the present animal model. PMID:18800255

  3. Construction of amphiphilic copolymer nanoparticles based on gelatin as drug carriers for doxorubicin delivery.

    PubMed

    Han, Siyuan; Li, Mingjun; Liu, Xiangang; Gao, Hongxia; Wu, Yan

    2013-02-01

    Novel biodegradable amphiphilic copolymer nanoparticles based on gelatin, poly(lactide) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) (gelatin-co-PLA-DPPE) have been successfully fabricated. In order to estimate the feasibility as drug carriers, an anti-tumor model drug doxorubicin hydrochloride salt (DOX) was incorporated into polymeric nanoparticles by double emulsion or nanoprecipitation method. The nanoparticle size, size distribution and encapsulation efficiency (EE) were influenced by the feed weight ratio of the copolymer to DOX and different fabrication methods of nanoparticles. In addition, in vitro release experiments exhibited the release behavior was affected by pH of release media. The DOX-loaded nanoparticles showed that faster release at pH 5.0 than their release at pH 7.4 buffer. The DOX-loaded copolymer nanoparticles showed comparable anticancer efficacy with the free drug in vitro and in vivo. These results demonstrate a feasible application of the gelatin derivative as a promising nanocarrier for delivery of anti-tumor drugs. PMID:23107962

  4. Vitamin B1 derived blue and green fluorescent carbon nanoparticles for cell-imaging application.

    PubMed

    Bhunia, Susanta Kumar; Pradhan, Nibedita; Jana, Nikhil R

    2014-05-28

    A carbon-based fluorescent nanoparticle is considered to be a new generation nontoxic nanoprobe suitable for various bioimaging and sensing applications. However, the synthesis of such a high-quality nanoparticle is challenging, and its application potential is mostly unexplored. Here we report a vitamin B1 carbonization-based approach for blue and green fluorescent carbon nanoparticles of <10 nm size with a fluorescence quantum of up to 76%. We found that carbonization of vitamin B1 in the presence of phosphate salt at ?90-130 °C for about 2 h produces highly fluorescent carbon nanoparticles of 1-6 nm size. The particle size and fluorescence property can be controlled by varying the reaction temperature and nature of phosphate salt. Elemental analysis shows the incorporation of a large percentage (up to 48 wt %) of other elements (such as nitrogen, oxygen, phophorus, and sulfur) in the carbon matrix. The chemical structure of vitamin B1 (thiamine) is unique in a sense that it consists of a large number of heteroatoms along with unsaturated bonds and offers low-temperature carbonization with the formation of a nanoparticle having an optimum ratio of sp(2) and sp(3) carbon atoms. These carbon nanoparticles have high colloidal stability and stable fluorescence and have been used as fluorescent imaging probes. PMID:24697797

  5. Perovskite ceramic nanoparticles in polymer composites for augmenting bone tissue regeneration.

    PubMed

    Bagchi, Amrit; Meka, Sai Rama Krishna; Rao, Badari Narayana; Chatterjee, Kaushik

    2014-12-01

    There is increasing interest in the use of nanoparticles as fillers in polymer matrices to develop biomaterials which mimic the mechanical, chemical and electrical properties of bone tissue for orthopaedic applications. The objective of this study was to prepare poly(?-caprolactone) (PCL) nanocomposites incorporating three different perovskite ceramic nanoparticles, namely, calcium titanate (CT), strontium titanate (ST) and barium titanate (BT). The tensile strength and modulus of the composites increased with the addition of nanoparticles. Scanning electron microscopy indicated that dispersion of the nanoparticles scaled with the density of the ceramics, which in turn played an important role in determining the enhancement in mechanical properties of the composite. Dielectric spectroscopy revealed improved permittivity and reduced losses in the composites when compared to neat PCL. Nanofibrous scaffolds were fabricated via electrospinning. Induction coupled plasma-optical emission spectroscopy indicated the release of small quantities of Ca(+2), Sr(+2), Ba(+2) ions from the scaffolds. Piezo-force microscopy revealed that BT nanoparticles imparted piezoelectric properties to the scaffolds. In vitro studies revealed that all composites support osteoblast proliferation. Expression of osteogenic genes was enhanced on the nanocomposites in the following order: PCL/CT > PCL/ST > PCL/BT > PCL. This study demonstrates that the use of perovskite nanoparticles could be a promising technique to engineer better polymeric scaffolds for bone tissue engineering. PMID:25379989

  6. 3D optical printing of piezoelectric nanoparticle-polymer composite materials.

    PubMed

    Kim, Kanguk; Zhu, Wei; Qu, Xin; Aaronson, Chase; McCall, William R; Chen, Shaochen; Sirbuly, Donald J

    2014-10-28

    Here we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be optically printed into three-dimensional (3D) microstructures using digital projection printing. Piezoelectric polymers were fabricated by incorporating barium titanate (BaTiO3, BTO) nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate and exposing to digital optical masks that could be dynamically altered to generate user-defined 3D microstructures. To enhance the mechanical-to-electrical conversion efficiency of the composites, the BTO nanoparticles were chemically modified with acrylate surface groups, which formed direct covalent linkages with the polymer matrix under light exposure. The composites with a 10% mass loading of the chemically modified BTO nanoparticles showed piezoelectric coefficients (d(33)) of ? 40 pC/N, which were over 10 times larger than composites synthesized with unmodified BTO nanoparticles and over 2 times larger than composites containing unmodified BTO nanoparticles and carbon nanotubes to boost mechanical stress transfer efficiencies. These results not only provide a tool for fabricating 3D piezoelectric polymers but lay the groundwork for creating highly efficient piezoelectric polymer materials via nanointerfacial tuning. PMID:25046646

  7. Perovskite ceramic nanoparticles in polymer composites for augmenting bone tissue regeneration

    NASA Astrophysics Data System (ADS)

    Bagchi, Amrit; Rama Krishna Meka, Sai; Narayana Rao, Badari; Chatterjee, Kaushik

    2014-12-01

    There is increasing interest in the use of nanoparticles as fillers in polymer matrices to develop biomaterials which mimic the mechanical, chemical and electrical properties of bone tissue for orthopaedic applications. The objective of this study was to prepare poly(?-caprolactone) (PCL) nanocomposites incorporating three different perovskite ceramic nanoparticles, namely, calcium titanate (CT), strontium titanate (ST) and barium titanate (BT). The tensile strength and modulus of the composites increased with the addition of nanoparticles. Scanning electron microscopy indicated that dispersion of the nanoparticles scaled with the density of the ceramics, which in turn played an important role in determining the enhancement in mechanical properties of the composite. Dielectric spectroscopy revealed improved permittivity and reduced losses in the composites when compared to neat PCL. Nanofibrous scaffolds were fabricated via electrospinning. Induction coupled plasma-optical emission spectroscopy indicated the release of small quantities of Ca+2, Sr+2, Ba+2 ions from the scaffolds. Piezo-force microscopy revealed that BT nanoparticles imparted piezoelectric properties to the scaffolds. In vitro studies revealed that all composites support osteoblast proliferation. Expression of osteogenic genes was enhanced on the nanocomposites in the following order: PCL/CT > PCL/ST > PCL/BT > PCL. This study demonstrates that the use of perovskite nanoparticles could be a promising technique to engineer better polymeric scaffolds for bone tissue engineering.

  8. A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles

    PubMed Central

    2011-01-01

    Numerous luminophores may be encapsulated into silica nanoparticles (< 100 nm) using the reverse microemulsion process. Nevertheless, the behaviour and effect of such luminescent molecules appear to have been much less studied and may possibly prevent the encapsulation process from occurring. Such nanospheres represent attractive nanoplatforms for the development of biotargeted biocompatible luminescent tracers. Physical and chemical properties of the encapsulated molecules may be affected by the nanomatrix. This study examines the synthesis of different types of dispersed silica nanoparticles, the ability of the selected luminophores towards incorporation into the silica matrix of those nanoobjects as well as the photophysical properties of the produced dye-doped silica nanoparticles. The nanoparticles present mean diameters between 40 and 60 nm as shown by TEM analysis. Mainly, the photophysical characteristics of the dyes are retained upon their encapsulation into the silica matrix, leading to fluorescent silica nanoparticles. This feature article surveys recent research progress on the fabrication strategies of these dye-doped silica nanoparticles. PMID:21711855

  9. Study of bactericidal properties of carbohydrate-stabilized platinum oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Rezaei-Zarchi, Saeed; Imani, Saber; mohammad Zand, Ali; Saadati, Mojtaba; Zaghari, Zahra

    2012-09-01

    Platinum oxide nanoparticles were prepared by a simple hydrothermal route and chemical reduction using carbohydrates (fructose and sucrose) as the reducing and stabilizing agents. In comparison with other metals, platinum oxide has less environmental pollution. Therefore, Pt is considered an appropriate candidate to deal with environmental pathogens. The crystallite size of these nanoparticles was evaluated from X-ray diffraction, atomic force microscopy, and transmission electron microscopy (TEM) and was found to be 10 nm, which is the demonstration of EM bright field and transmission electron microscopy. The effect of carbohydrates on the morphology of the nanoparticles was studied using TEM. The nanoparticles were administered to the Pseudomonas stutzeri and Lactobacillus cultures, and the incubation was done at 37°C for 24 h. The nanocomposites exhibited interesting inhibitory as well as bactericidal activity against P. stutzeri and Lactobacillus species. Incorporation of nanoparticles also increased the thermal stability of the carbohydrates. The results of this paper showed that carbohydrates can serve as a carrier for platinum oxide nanoparticles, and nanocomposites can have potential biological applications.

  10. Manganese-containing Prussian blue nanoparticles for imaging of pediatric brain tumors

    PubMed Central

    Dumont, Matthieu F; Yadavilli, Sridevi; Sze, Raymond W; Nazarian, Javad; Fernandes, Rohan

    2014-01-01

    Pediatric brain tumors (PBTs) are a leading cause of death in children. For an improved prognosis in patients with PBTs, there is a critical need to develop molecularly-specific imaging agents to monitor disease progression and response to treatment. In this paper, we describe manganese-containing Prussian blue nanoparticles as agents for molecular magnetic resonance imaging (MRI) and fluorescence-based imaging of PBTs. Our core-shell nanoparticles consist of a core lattice structure that incorporates and retains paramagnetic Mn2+ ions, and generates MRI contrast (both negative and positive). The biofunctionalized shell is comprised of fluorescent avidin, which serves the dual purpose of enabling fluorescence imaging and functioning as a platform for the attachment of biotinylated ligands that target PBTs. The surfaces of our nanoparticles are modified with biotinylated antibodies targeting neuron-glial antigen 2 or biotinylated transferrin. Both neuron-glial antigen 2 and the transferrin receptor are protein markers overexpressed in PBTs. We describe the synthesis, biofunctionalization, and characterization of these multimodal nanoparticles. Further, we demonstrate the MRI and fluorescence imaging capabilities of manganese-containing Prussian blue nanoparticles in vitro. Finally, we demonstrate the potential of these nanoparticles as PBT imaging agents by measuring their organ and brain biodistribution in an orthotopic mouse model of PBTs using ex vivo fluorescence imaging. PMID:24920896

  11. Carcinogenicity of inhaled nanoparticles.

    PubMed

    Roller, Markus

    2009-07-01

    Large epidemiological studies in the United States have shown a statistical association between air concentration of the fine dust fraction PM(2.5) in the general environment and increased risk of lung cancer. A quantitative risk assessment for lung cancer based on these studies corresponds to risk estimates based on studies at workplaces with exposure to diesel engine emissions; its magnitude cannot be explained by the known carcinogenicity of organic substances or metals adsorbed to the insoluble particle core. Carcinogenic effects of diesel particles were observed after inhalation in rats independently in several studies. The surprisingly strong effect of diesel particles was partially attributed to their small size. This hypothesis was corroborated by inhalation studies with synthetic nanoparticles virtually free of organic compounds. IARC found sufficient evidence for the carcinogenicity of carbon black and of titanium dioxide in experimental animals. Long-term studies by the method of intratracheal instillation confirmed the carcinogenic effects in rats for an even broader spectrum of synthetic nanoparticles. Non-positive studies with hamsters are not valid because hamsters did not develop lung tumors after inhalation of some known human carcinogens. In recent years, the number of publications reporting in vitro genotoxicity of TiO(2) and of carbon black nanomaterials has increased. Overall, there is clear positive evidence for carcinogenicity in rats, together with supporting evidence from human data of structurally related substances. Therefore, the European Union (EU) criteria for category 2 of carcinogenic substances appear to be fulfilled for bio-durable nanoparticles consisting of matter without known significant specific toxicity. PMID:19558247

  12. Achieving enhanced DSSC performance by microwave plasma incorporation of carbon into TiO2 photoelectrodes

    NASA Astrophysics Data System (ADS)

    Dang, Binh H. Q.; MacElroy, Don; Dowling, Denis P.

    2013-06-01

    The photoactivity of carbon-incorporated titanium dioxide (TiO2) has been widely reported. This study involves a novel approach to the incorporation of carbon into TiO2 through the use of microwave plasma processing. The process involved thermally treating printed TiO2 nanoparticle coatings in a microwave-induced argon-oxygen plasma containing low concentrations of methane. The resulting deposited carbon layer was characterized using XRD, XPS, Raman, UV-vis, ellipsometry, and optical profilometry. It was found that the methane gas was dissociated in the microwave plasma into its carbon species, which were then deposited as a nm-thick layer onto the TiO2 coatings, most likely in the form of graphite. The photovoltaic performances of both the TiO2 and the carbon-incorporated TiO2 were assessed through J-V and IPCE measurements of the N719-sensitized solar cells using the titania as their photoanodes. Up to a 72% improvement in the maximum power density (Pd-max) was observed for the carbon-incorporated TiO2 samples as compared to the TiO2, onto which no carbon was added. This improvement was found to be mainly associated with an increase in the short-circuit current density (Jsc), but independent from the open-circuit voltage (Voc), the filter factor (FF), and the level of dye adsorption. Possible contributory factors to the improved performance of the carbon-incorporated TiO2 were the enhanced electron conductivity and electron lifetime, both of which were elucidated through electrochemical impedance spectroscopy (EIS). When the surface layer was examined using XPS, the optimal carbon content on the TiO2 coating surface was found to be 8.4%, beyond which there was a reduction in the DSSC efficiency.

  13. The biodistribution of self-assembling protein nanoparticles shows they are promising vaccine platforms

    PubMed Central

    2013-01-01

    Background Because of the need to limit side-effects, nanoparticles are increasingly being studied as drug-carrying and targeting tools. We have previously reported on a scheme to produce protein-based self-assembling nanoparticles that can act as antigen display platforms. Here we attempted to use the same system for cancer-targeting, making use of a C-terminal bombesin peptide that has high affinity for a receptor known to be overexpressed in certain tumors, as well as an N-terminal polyhistidine tag that can be used for radiolabeling with technetium tricarbonyl. Results In order to increase circulation time, we experimented with PEGylated and unPEGylated varities typo particle. We also tested the effect of incorporating different numbers of bombesins per nanoparticle. Biophysical characterization determined that all configurations assemble into regular particles with relatively monodisperse size distributions, having peaks of about 33 – 36 nm. The carbonyl method used for labeling produced approximately 80% labeled nanoparticles. In vitro, the nanoparticles showed high binding, both specific and non-specific, to PC-3 prostate cancer cells. In vivo, high uptake was observed for all nanoparticle types in the spleens of CD-1 nu/nu mice, decreasing significantly over the course of 24 hours. High uptake was also observed in the liver, while only low uptake was seen in both the pancreas and a tumor xenograft. Conclusions The data suggest that the nanoparticles are non-specifically taken up by the reticuloendothelial system. Low uptake in the pancreas and tumor indicate that there is little or no specific targeting. PEGylation or increasing the amount of bombesins per nanoparticle did not significantly improve targeting. In particular, the uptake in the spleen, which is a primary organ of the immune system, highlights the potential of the nanoparticles as vaccine carriers. Also, the decrease in liver and spleen radioactivity with time implies that the nanoparticles are broken down and cleared. This is an important finding, as it shows that the nanoparticles can be safely used as a vaccine platform without the risk of prolonged side effects. Furthermore, it demonstrates that technetium carbonyl radiolabeling of our protein-based nanoparticles can be used to evaluate their pharmacokinetic properties in vivo. PMID:24219600

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

    PubMed

    Mullen, Douglas G; Banaszak Holl, Mark M

    2011-11-15

    Nanoparticles conjugated with functional ligands are expected to have a major impact in medicine, photonics, sensing, and nanoarchitecture design. One major obstacle to realizing the promise of these materials, however, is the difficulty in controlling the ligand/nanoparticle ratio. This obstacle can be segmented into three key areas: First, many designs of these systems have failed to account for the true heterogeneity of ligand/nanoparticle ratios that compose each material. Second, studies in the field often use the mean ligand/nanoparticle ratio as the accepted level of characterization of these materials. This measure is insufficient because it does not provide information about the distribution of ligand/nanoparticle species within a sample or the number and relative amount of the different species that compose a material. Without these data, researchers do not have an accurate definition of material composition necessary both to understand the material-property relationships and to monitor the consistency of the material. Third, some synthetic approaches now in use may not produce consistent materials because of their sensitivity to reaction kinetics and to the synthetic history of the nanoparticle. In this Account, we describe recent advances that we have made in under standing the material composition of ligand-nanoparticle systems. Our work has been enabled by a model system using poly(amidoamine) dendrimers and two small molecule ligands. Using reverse phase high-pressure liquid chromatography (HPLC), we have successfully resolved and quantified the relative amounts and ratios of each ligand/dendrimer combination. This type of information is rare within the field of ligand-nanoparticle materials because most analytical techniques have been unable to identify the components in the distribution. Our experimental data indicate that the actual distribution of ligand-nanoparticle components is much more heterogeneous than is commonly assumed. The mean ligand/nanoparticle ratio that is typically the only information known about a material is insufficient because the mean does not provide information on the diversity of components in the material and often does not describe the most common component (the mode). Additionally, our experimental data has provided examples of material batches with the same mean ligand/nanoparticle ratio and very different distributions. This discrepancy indicates that the mean cannot be used as the sole metric to assess the reproducibility of a system. We further found that distribution profiles can be highly sensitive to the synthetic history of the starting material as well as slight changes in reaction conditions. We have incorporated the lessons from our experimental data into the design of new ligand-nanoparticle systems to provide improved control over these ratios. PMID:21812474

  15. Hydrothermal Growth of Mesoporous SBA-15 Silica in the Presence of PVP-Stabilized Pt Nanoparticles: Synthesis,

    E-print Network

    Yang, Peidong

    been synthesized by alcohol reduction methods and incorporated into mesoporous SBA-15 silica during it in a systematic way and then test its effect on catalytic performance. Several methods have been developed thus treatment and/or reduction with H2 to form metal nanoparticles.6,12,13 The process can be further refined

  16. Extended x-ray absorption fine structure studies of the atomic structure of nanoparticles in different metallic matrices

    Microsoft Academic Search

    S H Baker; M Roy; S J Gurman; C Binns

    2009-01-01

    It has been appreciated for some time that the novel properties of particles in the size range 1–10 nm are potentially exploitable in a range of applications. In order to ultimately produce commercial devices containing nanosized particles, it is necessary to develop controllable means of incorporating them into macroscopic samples. One way of doing this is to embed the nanoparticles

  17. TOPICAL REVIEW: Extended x-ray absorption fine structure studies of the atomic structure of nanoparticles in different metallic matrices

    Microsoft Academic Search

    S. H. Baker; M. Roy; S. J. Gurman; C. Binns

    2009-01-01

    It has been appreciated for some time that the novel properties of particles in the size range 1-10 nm are potentially exploitable in a range of applications. In order to ultimately produce commercial devices containing nanosized particles, it is necessary to develop controllable means of incorporating them into macroscopic samples. One way of doing this is to embed the nanoparticles

  18. Triggered Nanoparticles as Therapeutics

    PubMed Central

    Kim, Chang Soo; Duncan, Bradley; Creran, Brian; Rotello, Vincent M.

    2013-01-01

    Summary Drug delivery systems (DDSs) face several challenges including site-specific delivery, stability, and the programmed release of drugs. Engineered nanoparticle (NP) surfaces with responsive moieties can enhance the efficacy of DDSs for in vitro and in vivo systems. This triggering process can be achieved through both endogenous (biologically controlled release) and exogenous (external stimuli controlled release) activation. In this review, we will highlight recent examples of the use of triggered release strategies of engineered nanomaterials for in vitro and in vivo applications. PMID:24159362

  19. Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

    NASA Astrophysics Data System (ADS)

    Kumar, Sachin; Chatterjee, Kaushik

    2015-01-01

    The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(?-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(?-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05060f

  20. Incorporated Research Institutions for Seismology (IRIS) Consortium

    NSDL National Science Digital Library

    The Incorporated Research Institutions for Seismology (IRIS) is a consortium of 91 US Universities with research interests in seismology. IRIS was established in an effort "to develop and operate the infrastructure needed for the acquisition and distribution of high quality seismic data." One highlight is the Data Management System, which incorporates six data collection centers to coordinate data inflow from the 128 seismic recording stations that make up IRIS's Global Seismographic Network (GSN). Other features include a seismic monitor link for a quick view of current seismic activity. The SeismiQuery Database allows users to search out available data by day, month, station, event, and more. Further, a station book "contains information about stations from all networks that contribute data." Finally, this fine site also features Special Event Pages, an excellent collection of links to specific sites, graphics, and general information on recent earthquakes (see the September 1, 1999 Scout Report for Science & Engineering).