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1

Kaempferol nanoparticles achieve strong and selective inhibition of ovarian cancer cell viability  

PubMed Central

Ovarian cancer is one of the leading causes of cancer death for women throughout the Western world. Kaempferol, a natural flavonoid, has shown promise in the chemoprevention of ovarian cancer. A common concern about using dietary supplements for chemoprevention is their bioavailability. Nanoparticles have shown promise in increasing the bioavailability of some chemicals. Here we developed five different types of nanoparticles incorporating kaempferol and tested their efficacy in the inhibition of viability of cancerous and normal ovarian cells. We found that positively charged nanoparticle formulations did not lead to a significant reduction in cancer cell viability, whereas nonionic polymeric nanoparticles resulted in enhanced reduction of cancer cell viability. Among the nonionic polymeric nanoparticles, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) nanoparticles incorporating kaempferol led to significant reduction in cell viability of both cancerous and normal cells. Poly(DL-lactic acid-co-glycolic acid) (PLGA) nanoparticles incorporating kaempferol resulted in enhanced reduction of cancer cell viability together with no significant reduction in cell viability of normal cells compared with kaempferol alone. Therefore, both PEO-PPO-PEO and PLGA nanoparticle formulations were effective in reducing cancer cell viability, while PLGA nanoparticles incorporating kaempferol had selective toxicity against cancer cells and normal cells. A PLGA nanoparticle formulation could be advantageous in the prevention and treatment of ovarian cancers. On the other hand, PEO-PPO-PEO nanoparticles incorporating kaempferol were more effective inhibitors of cancer cells, but they also significantly reduced the viability of normal cells. PEO-PPO-PEO nanoparticles incorporating kaempferol may be suitable as a cancer-targeting strategy, which could limit the effects of the nanoparticles on normal cells while retaining their potency against cancer cells. We have identified two nanoparticle formulations incorporating kaempferol that may lead to breakthroughs in cancer treatment. Both PEO-PPO-PEO and PLGA nanoparticle formulations had superior effects compared with kaempferol alone in reducing cancer cell viability.

Luo, Haitao; Jiang, Bingbing; Li, Bingyun; Li, Zhaoliang; Jiang, Bing-Hua; Chen, Yi Charlie

2012-01-01

2

Permanent hair dye-incorporated hyaluronic acid nanoparticles.  

PubMed

We prepared p-phenylenediamine (PDA)-incorporated nanoparticles using hyaluronic acid (HA). PDA-incorporated HA nanoparticles have spherical shapes and sizes were less than 300?nm. The results of FT-IR spectra indicated that PDA-incorporated HA nanoparticles were formed by ion-complex formation between amine group of PDA and carboxyl group of HA. Furthermore, powder-X-ray diffractogram (XRD) measurement showed that intrinsic crystalline peak of PDA disappeared by formation of nanoparticle with HA at XRD measurement. These results indicated that PDA-incorporated HA nanoparticles were formed by ion-complex formation. At drug release study, the higher PDA contents induced faster release rate from nanoparticles. PDA-incorporated nanoparticles showed reduced intrinsic toxicity against HaCaT human keratinocyte cells at MTT assay and apoptosis assay. We suggest that PDA-incorporated HA nanoparticles are promising candidates for novel permanent hair dye. PMID:23088321

Lee, Hye-Young; Jeong, Young-Il; Kim, Da-Hye; Choi, Ki-Choon

2012-10-22

3

Anti-reflective optical coatings incorporating nanoparticles  

Microsoft Academic Search

This paper presents a simple approach for forming anti-reflective film stacks on plastic substrates employing aqueous colloidal dispersions of metal oxide nanoparticles. Results demonstrate that it is possible to fabricate a polymeric thin film of continuously tunable refractive index over a wide range by loading the film with varying concentrations of metal oxide nanoparticles. Specifically, the refractive index for the

Kevin C Krogman; Thad Druffel; Mahendra K Sunkara

2005-01-01

4

Incorporation of the Model Drug Ubidecarenone into Solid Lipid Nanoparticles  

Microsoft Academic Search

Purpose. The impact of drug incorporation on melt-homogenized tripalmitin nanoparticles is investigated with ubidecarenone as a model drug. The dispersions are studied with respect to their drug loading capacity, localization and physical state of the drug as well as to potential changes of the nanoparticle properties due to interactions between drug and triglyceride matrix.

Heike Bunjes; Markus Drechsler; Michel H. J. Koch; Kirsten Westesen

2001-01-01

5

Antibacterial nano-structured titania coating incorporated with silver nanoparticles  

Microsoft Academic Search

Titanium (Ti) implants are widely used clinically but post-operation infection remains one of the most common and serious complications. A surface boasting long-term antibacterial ability is highly desirable in order to prevent implant associated infection. In this study, titania nanotubes (TiO2-NTs) incorporated with silver (Ag) nanoparticles are fabricated on Ti implants to achieve this purpose. The Ag nanoparticles adhere tightly

Lingzhou Zhao; Hairong Wang; Kaifu Huo; Lingyun Cui; Wenrui Zhang; Hongwei Ni; Yumei Zhang; Zhifen Wu; Paul K. Chu

2011-01-01

6

Incorporation of platinum nanoparticles in ordered mesoporous carbon  

Microsoft Academic Search

Platinum nanoparticles were incorporated within the pore system of ordered mesoporous carbon (OMC) by impregnating the carbon with a water-in-oil (w\\/o) microemulsion containing dissolved platinum salt followed by reduction of the platinum ions in situ inside the carbon pore system. The procedure provides preparation of metallic nanoparticles from hydrophilic precursors inside the hydrophobic carbon support structure with simultaneous control of

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

2007-01-01

7

Incorporation of platinum nanoparticles in ordered mesoporous carbon.  

PubMed

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

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

2006-10-05

8

Defining the drug incorporation properties of PLA-PEG nanoparticles.  

PubMed

The drug incorporation and physicochemical properties of PLA-PEG micellar like nanoparticles were examined in this study using a model water soluble drug, procaine hydrochloride. Procaine hydrochloride was incorporated into nanoparticles made from a series of PLA-PEG copolymers with a fixed PEG block (5 kDa) and a varying PLA segment (3-110 kDa). The diameter of the PLA-nanoparticles increased from 27.7 to 174.6 nm, with an increase in the PLA molecular weight. However, drug incorporation efficiency remained similar throughout the series. Incorporation of drug into the smaller PLA-PEG nanoparticles made from 3:5, 15:5 and 30:5 copolymers did not influence the particle size, while an increase was observed for the larger systems comprising 75:5 and 110:5 copolymers. An increase in drug content for PLA-PEG 30:5 nanoparticles was achieved by increasing the theoretical loading (quantity of initially present drug). The size of these nanoparticles remained unchanged with the increasing drug content, supporting the proposed micellar type structure of the PLA-PEG 30:5 nanoparticles. The morphology of these systems remained unchanged both at low and high theoretical drug loadings. Formulation variables, such as an increase in the aqueous phase pH, replacement with the base form of the drug and inclusion of lauric acid in the formulation did not improve the incorporation efficiency of drug into PLA-PEG 30:5 nanoparticles. While poly(aspartic acid) as a complexation agent did not improve the drug incorporation efficiency of procaine hydrochloride, it did so for another water soluble drug diminazene aceturate. This may be attributed to a stronger interaction of diminazene aceturate with poly(aspartic acid) relative to procaine hydrochloride, as confirmed by thermodynamic analysis of isothermal titration calorimetric data. The drug incorporation and physicochemical characterisation data obtained in this study may be relevant in optimising the drug incorporation and delivery properties of these potential drug targeting carriers. PMID:10794931

Govender, T; Riley, T; Ehtezazi, T; Garnett, M C; Stolnik, S; Illum, L; Davis, S S

2000-04-10

9

Inorganic-organic materials incorporating alumoxane nanoparticles  

NASA Astrophysics Data System (ADS)

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 a resin and hardener system, to form a composite material. Solid state NMR spectroscopy demonstrates that the alumoxanes are chemically bound to the resin matrix. The properties and cure times of the alumoxane materials are distinct from both the pure resins and from a physical blend of the resins with traditional fillers. A significant increase in thermal stability and tensile strength is observed for the resin systems. In order to produce molecular coupling layers, epoxides cross-linked with self-assembled monolayers (SAMs) grown on the native oxide of aluminum thin films on silicon substrates have been investigated. Specifically, SAMs have been formed by the attachment of different carboxylic acids. In order to investigate the cross-linking reaction between carboxylate monolayers and an epoxide, grown monolayers were reacted with a mono-epoxy resin. In addition to these surface materials, aluminum oxide surfaces supporting carboxylate monolayers were reacted in pairs with DER 332 to form a structural adhesive. These materials have been characterized variously by SEM, AFM, XPS, EDX, and contact angle measurements. The particle size dependence on pH of a series of alumoxanes was investigated. For each of the alumoxanes, PCS particle size measurements were obtained as a function of pH. In all cases, particle size control was afforded by variations in pH. Finally, crystal structures of several model compounds were determined by X-ray crystallography, and shown to form either sheets of dimers or tetrameric units. Through a review of structures found in the Cambridge Crystallographic Database, compounds of the type X-CH(OH)CH 2NH-Y were investigated. The results of this study lead to a generalized approach for predicting the packing motifs of racemic mixtures in polar space groups.

Vogelson, Cullen Taylor

10

Incorporation of zirconia into coatings formed by DC plasma electrolytic oxidation of aluminium in nanoparticle suspensions  

Microsoft Academic Search

A study has been carried out to investigate the incorporation of zirconia into alumina-based coatings formed on aluminium using DC plasma electrolytic oxidation in phosphate and silicate electrolytes containing zirconia nanoparticles in suspension. The nanoparticles were incorporated mainly near the coating surface and within cavities inside the coatings. Additionally, a silicon-rich, surface deposit appeared to entrain the nanoparticles of the

E. Matykina; R. Arrabal; F. Monfort; P. Skeldon; G. E. Thompson

2008-01-01

11

Magneto-Optical Kerr Effects of Yttrium-Iron Garnet Thin Films Incorporating Gold Nanoparticles  

Microsoft Academic Search

We report an experimental study on magneto-optical (MO) Kerr effects of yttrium-iron garnet (YIG) thin films incorporating Au nanoparticles. The polar MO Kerr spectra in the wavelength between 400 and 800 nm show that, by incorporating the Au nanoparticles, Kerr rotation angles become negative values in the region, where the localized surface plasmon polariton (SPP) resonance of the Au nanoparticles

Satoshi Tomita; Takeshi Kato; Shigeru Tsunashima; Satoshi Iwata; Minoru Fujii; Shinji Hayashi

2006-01-01

12

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

Microsoft Academic Search

Bifunctional nanoprobes with both magnetic and optical contrast have been developed for ultra-sensitive brain tumor imaging at the cellular level. The nanoprobes were synthesized by simultaneously incorporating a magnetite nanoparticle cluster and fluorescence dyes into silica encapsulation by a sol-gel approach under ultrasonic treatment. The nanoprobes maintain superparamagnetic behavior at room temperature and possess enhanced transverse relaxivity and good photostability.

Jiaqi Wan; Xiangxi Meng; Enzhong Liu; Kezheng Chen

2010-01-01

13

Kaempferol glycosides from Siparuna apiosyce.  

PubMed

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

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

2000-11-01

14

Antibacterial nano-structured titania coating incorporated with silver nanoparticles.  

PubMed

Titanium (Ti) implants are widely used clinically but post-operation infection remains one of the most common and serious complications. A surface boasting long-term antibacterial ability is highly desirable in order to prevent implant associated infection. In this study, titania nanotubes (TiO(2)-NTs) incorporated with silver (Ag) nanoparticles are fabricated on Ti implants to achieve this purpose. The Ag nanoparticles adhere tightly to the wall of the TiO(2)-NTs prepared by immersion in a silver nitrate solution followed by ultraviolet light radiation. The amount of Ag introduced to the NTs can be varied by changing processing parameters such as the AgNO(3) concentration and immersion time. The TiO(2)-NTs loaded with Ag nanoparticles (NT-Ag) can kill all the planktonic bacteria in the suspension during the first several days, and the ability of the NT-Ag to prevent bacterial adhesion is maintained without obvious decline for 30 days, which are normally long enough to prevent post-operation infection in the early and intermediate stages and perhaps even late infection around the implant. Although the NT-Ag structure shows some cytotoxicity, it can be reduced by controlling the Ag release rate. The NT-Ag materials are also expected to possess satisfactory osteoconductivity in addition to the good biological performance expected of TiO(2)-NTs. This controllable NT-Ag structure which provides relatively long-term antibacterial ability and good tissue integration has promising applications in orthopedics, dentistry, and other biomedical devices. PMID:21565401

Zhao, Lingzhou; Wang, Hairong; Huo, Kaifu; Cui, Lingyun; Zhang, Wenrui; Ni, Hongwei; Zhang, Yumei; Wu, Zhifen; Chu, Paul K

2011-05-12

15

Etoposide-incorporated tripalmitin nanoparticles with different surface charge: Formulation, characterization, radiolabeling, and biodistribution studies  

Microsoft Academic Search

Etoposide-incorporated tripalmitin nanoparticles with negative (ETN) and positive charge (ETP) were prepared by melt emulsification\\u000a and high-pressure homogenization techniques. Spray drying of nanoparticles led to free flowing powder with excellent redispersibility.\\u000a The nanoparticles were characterized by size analysis, zeta potential measurements, and scanning electron microscopy. The\\u000a mean diameter of ETN and ETP nanoparticles was 391 nm and 362 nm, respectively,

Lakkireddy Harivardhan Reddy; Rakesh Kumar Sharma; Krishna Chuttani; Anil Kumar Mishra; Rayasa Ramachandra Murthy

2004-01-01

16

Paclitaxel-incorporated nanoparticles of hydrophobized polysaccharide and their antitumor activity.  

PubMed

The aim of this study was to characterize paclitaxel-incorporated polysaccharide nanoparticles and evaluate their antitumor activity in vitro and in vivo. Pullulan was hydrophobically modified using acetic anhydride to make the paclitaxel-incorporated nanoparticles. Pullulan acetate (PA) was used to encapsulate paclitaxel using the nanoprecipitation method. The particles had spherical shapes under electron microscopy with sizes <100 nm. The sizes of paclitaxel-incorporated nanoparticles increased to >100 nm, and higher drug feeding induced higher particle size and drug content. Initial drug burst release was observed until 2 days and then the drug was continuously released over 1 week. Intrinsic cytotoxicity of empty PA nanoparticles was tested with RAW264.7 macrophage cells for biocompatibilty. The viability of RAW264.7 cells was >93% at all concentrations of empty PA nanoparticles, indicating that the PA nanoparticles are not acutely cytotoxic to normal human cells. The nanoparticles showed lower antitumor activity in vitro against HCT116 human colon carcinoma cells than that of paclitaxel itself, indicating the sustained release properties of nanoparticles. An in vivo study using HCT116 human colon carcinoma-bearing mice showed that paclitaxel-incorporated PA nanoparticles reduced tumor growth more than that of paclitaxel itself. These results indicate that PA paclitaxel-incorporated nanoparticles are a promising candidate for antitumor drug delivery. PMID:22561793

Lee, Sang Joon; Hong, Gun-Young; Jeong, Young-Il; Kang, Mi-Sun; Oh, Jong-Suk; Song, Chae-Eun; Lee, Hyun Chul

2012-04-23

17

Controlled structure and properties of silicate nanoparticle networks for incorporation of biosystem components  

NASA Astrophysics Data System (ADS)

Inorganic nanoparticles are of technological interest in many fields. We created silicate nanoparticle hydrogels that effectively incorporated biomolecules that are unstable and involved in complicated reactions. The size of the silicate nanoparticles strongly affected both the physical characteristics of the resulting hydrogel and the activity of biomolecules incorporated within the hydrogel. We used high-resolution transmission electron microscopy (TEM) to analyze in detail the hydrogel network patterns formed by the silicate nanoparticles. We obtained clear nanostructured images of biomolecule-nanoparticle composite hydrogels. The TEM images also showed that larger silicate nanoparticles (22 nm) formed more loosely associated silicate networks than did smaller silicate nanoparticles (7 nm). The loosely associated networks formed from larger silicate nanoparticles might facilitate substrate diffusion through the network, thus promoting the observed increased activity of the entrapped biomolecules. This doubled the activity of the incorporated biosystems compared with that of biosystems prepared by our own previously reported method. We propose a reaction scheme to explain the formation of the silicate nanoparticle networks. The successful incorporation of biomolecules into the nanoparticle hydrogels, along with the high level of activity exhibited by the biomolecules required for complicated reaction within the gels, demonstrates the nanocomposites' potential for use in medical applications.

Sakai-Kato, Kumiko; Hasegawa, Toshiaki; Takaoka, Akio; Kato, Masaru; Toyo'oka, Toshimasa; Utsunomiya-Tate, Naoko; Kawanishi, Toru

2011-05-01

18

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

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

19

Magneto-optical Kerr effects of yttrium-iron garnet thin films incorporating gold nanoparticles.  

PubMed

We report an experimental study on magneto-optical (MO) Kerr effects of yttrium-iron garnet (YIG) thin films incorporating Au nanoparticles. The polar MO Kerr spectra in the wavelength between 400 and 800 nm show that, by incorporating the Au nanoparticles, Kerr rotation angles become negative values in the region, where the localized surface plasmon polariton (SPP) resonance of the Au nanoparticles is located. The anomalous Kerr rotation indicates a possible coupling between the MO Kerr effect of YIG and the SPP. A mechanism for the coupling is discussed. PMID:16712274

Tomita, Satoshi; Kato, Takeshi; Tsunashima, Shigeru; Iwata, Satoshi; Fujii, Minoru; Hayashi, Shinji

2006-04-28

20

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

NASA Astrophysics Data System (ADS)

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.

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

21

Polylactide nanoparticles containing stably incorporated cyanine dyes for in vitro and in vivo imaging applications  

Microsoft Academic Search

Stably incorporating fluorescent molecules to polymeric nanoparticles (NPs) or micelles can facilitate the prolonged tracking of these drug-delivery vehicles in vitro and in vivo. However, incorporation of fluorescent molecules, usually charged and thereby water-soluble, through the encapsulation strategy to hydrophobic polymer matrices is challenging. The encapsu- lated fluorescent agents are also subject to rapid release when the polymeric NPs are

Rong Tong; Virginia J. Coyle; Li Tang; Anne M. Barger; Timothy M. Fan; Jianjun Cheng

2010-01-01

22

Absorption of kaempferol from endive, a source of kaempferol-3-glucuronide, in humans  

Microsoft Academic Search

Objective: To determine the absorption, excretion and metabolism of kaempferol in humans.Design: A pharmacokinetic study of kaempferol from endive over 24 h.Subjects: Four healthy males and four healthy females.Results: Kaempferol, from a relatively low dose (9 mg), was absorbed from endive with a mean maximum plasma concentration of 0.1 ?M, at a time of 5.8 h, indicating absorption from the

M S DuPont; A J Day; R N Bennett; F A Mellon; P A Kroon; PA Kroon

2004-01-01

23

Incorporation of Metallic Nanoparticles into Conducting Polymer Actuator Films  

NASA Astrophysics Data System (ADS)

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

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

2009-07-01

24

Zinc incorporation capacity of whey protein nanoparticles prepared with desolvation with ethanol.  

PubMed

Whey protein isolate (WPI) nanoparticles were prepared using ethanol desolvation, and their capacity to incorporate ZnCl(2) was analysed. Desolvation was carried out at pH 9 and the volume of added ethanol was 0-3 times the volume of protein solution. The desolvated solutions were dispersed in acidified water (pH 3) immediately after desolvation. The size of the WPI nanoparticles increased with the volume ratio of ethanol:water used, as well as with the amount of ZnCl(2). The nanoparticles showed high incorporation efficiencies, and remained stable after 30 days of storage at 22 °C. The amount of zinc incorporated in the WPI particle suspensions was within the range of daily zinc requirements for healthy adults. PMID:22868157

Gülseren, ?brahim; Fang, Yuan; Corredig, Milena

2012-05-11

25

Peculiarities of the growth of KDP single crystals with incorporated aluminium oxyhydroxide nanoparticles  

NASA Astrophysics Data System (ADS)

Grown for the first time are KH2PO4 (KDP) crystals with incorporated aluminium oxyhydroxide Al2O3·nH2O nanoparticles (n=3.5-3.6). The influence of the nanoparticles on the structure perfection and the growth kinetics of the crystal faces are studied. The presence of the nanoparticles in the crystal matrix is confirmed by the results of chemical analysis, X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The most essential inhibiting effect of the nanoparticles is observed for the {100} faces. The mechanism of influence of the nanoparticles on the {100} faces growth is explained on the base of the Cabrera-Vermilyea (C-V) model using Langmuir adsorption isotherm.

Pritula, I. M.; Kosinova, A. V.; Vorontsov, D. A.; Kolybaeva, M. I.; Bezkrovnaya, O. N.; Tkachenko, V. F.; Vovk, O. M.; Grishina, E. V.

2012-09-01

26

Highly Catalytically Active Palladium Nanoparticles Incorporated Inside Metal-Organic Framework Pores by Double Solvents Method  

NASA Astrophysics Data System (ADS)

Highly monodispersed palladium (Pd) nanoparticles have been successfully incorporated inside the mesopores of a metal-organic framework (MOF), MIL-101, without deposition of Pd nanoparticles on the external surfaces of framework by using the "double solvents" method, in which cyclohexane is used as a hydrophobic solvent to disperse the mesoporous MOF and an aqueous solution of Pd precursor is used as a hydrophilic solvent to fill the mesopores. The resulting Pd@MIL-101 composite is highly catalytically active for the reduction of 4-nitrophenol (4-NPh) by sodium borohydride (NaBH4). The observed excellent catalytic performances are attributed to the small Pd nanoparticles within the pores of MIL-101.

Yadav, Mahendra; Aijaz, Arshad; Xu, Qiang

2012-12-01

27

A microfluidic chemical/biological sensor based on dissolvable membrane incorporating gold nanoparticles and optical absorption  

NASA Astrophysics Data System (ADS)

We present a microfluidic chemical/biological sensor based on dissolvable membranes incorporating gold nanoparticles. The presence of the target analyte in a fluidic sample being assayed dissolves the membrane, causing the change in its optical absorption. To enhance the contrast between the membrane and the fluidic sample, the membranes are chemically treated to exhibit strong absorption at certain wavelengths. Here, we use N,N'-cystaminebisacrylamide (CBA) cross-linked poly(acrylamide) (PAAm) membranes dissolved by a sample solution containing dithioerythritol (DTT) to demonstrate this approach. The dissolvable membrane incorporates gold nanoparticles to exhibit strong absorption at 572nm.

Lo, Chi-Wei; Sridharamurthy, Sudheer S.; Jiang, Hongrui

2008-03-01

28

Optofluidics incorporating actively controlled micro- and nano-particles  

PubMed Central

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.

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

2012-01-01

29

Nanocomposite Materials - Ferroelectric Nanoparticles Incorporated into Porous Matrix  

NASA Astrophysics Data System (ADS)

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

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

30

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

PubMed Central

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

2012-01-01

31

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

32

Production and in vitro characterization of solid dosage form incorporating drug nanoparticles.  

PubMed

The objective of this study was to develop a tablet formulation of ketoconazole incorporating drug nanoparticles to enhance saturation solubility and dissolution velocity for enhancing bioavailability and reducing variability in systemic exposure. The bioavailability of ketoconazole is dissolution limited following oral administration. To enhance bioavailability and overcome variability in systemic exposure, a nanoparticle formulation of ketoconazole was developed. Ketoconazole nanoparticles were prepared using a media-milling technique. The nanosuspension was layered onto water-soluble carriers using a fluid bed processor. The nanosuspensions were characterized for particle size before and after layering onto water-soluble carriers. The saturation solubility and dissolution characteristics were investigated and compared with commercial ketoconazole formulation to ascertain the impact of particle size on drug dissolution. The drug nanoparticles were evaluated for solid-state transitions before and after milling using differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). This study demonstrated that tablet formulation incorporating ketoconazole nanoparticles showed significantly faster rate of drug dissolution in a discriminating dissolution medium as compared with commercially available tablet formulation. There was no affect on solid-state properties of ketoconazole following milling. The manufacturing process used is relatively simple and scalable indicating general applicability to enhance dissolution and bioavailability of many sparingly soluble compounds. PMID:18720147

Basa, Shradhanjali; Muniyappan, Thilekkumar; Karatgi, Pradeep; Prabhu, Raghavendra; Pillai, Ravi

2008-11-01

33

Kaempferol is an estrogen-related receptor ? and ? inverse agonist  

Microsoft Academic Search

Kaempferol is a dietary flavonoid that is thought to function as a selective estrogen receptor modulator. In this study, we established that kaempferol also functions as an inverse agonist for estrogen-related receptors alpha and gamma (ERR? and ERR?). We demonstrated that kaempferol binds to ERR? and ERR? and blocks their interaction with coactivator peroxisome proliferator-activated receptor ? coactivator-1? (PGC-1?). Kaempferol

Junjian Wang; Fang Fang; Zhiyan Huang; Yanfei Wang; Chiwai Wong

2009-01-01

34

Plasmon resonance at extreme temperatures in sputtered Au nanoparticle incorporated TiO2 films  

NASA Astrophysics Data System (ADS)

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. Au nanoparticle incorporated metal oxide thin films have recently been demonstrated to show a useful optical response to changing ambient gases at high temperatures as a result of modifications to the localized surface plasmon resonance (LSPR) of the Au nanoparticles. Au nanoparticle incorporated TiO2 films were prepared through sputter deposition techniques followed by high temperature oxidation treatments. Upon exposure to a 4% H2/N2 gas atmosphere at elevated temperatures, a shift of the absorption resonance associated with Au nanoparticles to shorter wavelengths is observed, as demonstrated in the literature previously. In this work, we also demonstrate that there is a shift of similar magnitude in the scattering resonance associated with Au. The LSPR absorption peak was monitored as a function of temperature up to 850oC demonstrating a broadening and a decrease in the maximum peak absorptance. Calculations performed in the quasistatic approximation are also presented to explain observed changes in LSPR as a function of temperature and to illustrate the effects on sensitivity of Au - based LSPR sensor materials for extreme temperature applications.

Ohodnicki, Paul R.; Brown, Thomas D.; Buric, Michael P.; Baltrus, John P.; Chorpening, B.

2012-09-01

35

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

PubMed Central

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.

Chladek, Grzegorz; Kasperski, Jacek; Barszczewska-Rybarek, Izabela; Zmudzki, Jaroslaw

2013-01-01

36

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

PubMed

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

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

2013-01-20

37

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

SciTech Connect

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.

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

38

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

PubMed Central

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.

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

39

Sonoelectrochemical synthesis of highly photoelectrochemically active TiO2 nanotubes by incorporating CdS nanoparticles  

Microsoft Academic Search

Self-organized anodic TiO2 nanotube arrays (TiO2NTs) are functionalized with CdS nanoparticle based perfusion and deposition through a single-step sonoelectrodeposition method. Even controlled at 50 °C, CdS nanoparticles with smaller size and more homogeneous distribution are successfully synthesized in dimethyl sulfoxide (DMSO) under ultrasonic irradiation. Moreover, TiO2 nanotubes can be filled with nanoparticles because of the ultrasonic effect. The CdS incorporated

Cheng Lin Wang; Lan Sun; Hong Yun; Jing Li; Yue Kun Lai; Chang Jian Lin

2009-01-01

40

5-aminolevulinic acid-incorporated nanoparticles of methoxy poly(ethylene glycol)-chitosan copolymer for photodynamic therapy  

PubMed Central

Purpose The aim of this study was to make 5-aminolevulinic acid (5-ALA)-incorporated nanoparticles using methoxy polyethylene glycol/chitosan (PEG-Chito) copolymer for application in photodynamic therapy for colon cancer cells. Methods 5-ALA-incorporated (PEG-Chito-5-ALA) nanoparticles were prepared by ion complex formation between 5-ALA and chitosan. Protoporphyrin IX accumulation in the tumor cells and phototoxicity induced by PEG-Chito-5-ALA nanoparticles were assessed using CT26 cells in vitro. Results PEG-Chito-5-ALA nanoparticles have spherical shapes with sizes diameters 200 nm. More specifically, microscopic observation revealed a core-shell structure of PEG-Chito-5-ALA nanoparticles. 1H NMR spectra showed that 5-ALA was incorporated in the core of the nanoparticles. In the absence of light irradiation, all components such as 5-ALA, empty nanoparticles, and PEG-Chito-5-ALA nanoparticles did not affect the viability of cells. However, 5-ALA or PEG-Chito-5-ALA nanoparticles induced tumor cell death under light irradiation, and the viability of tumor cells was dose-dependently decreased according to the increase in irradiation time. In particular, PEG-Chito-5-ALA nanoparticles induced increased phototoxicity and higher protoporphyrin IX accumulation into the tumor cells than did 5-ALA alone. Furthermore, PEG-Chito-5-ALA nanoparticles accelerated apoptosis/necrosis of tumor cells, compared to 5-ALA alone. Conclusion PEG-Chito-5-ALA nanoparticles showed superior delivery capacity of 5-ALA and phototoxicity against tumor cells. These results show that PEG-Chito-5-ALA nanoparticles are promising candidates for photodynamic therapy of colon cancer cells.

Chung, Chung-Wook; Chung, Kyu-Don; Jeong, Young-Il; Kang, Dae Hwan

2013-01-01

41

Incorporation of polyoxotungstate complexes in silica spheres and in situ formation of tungsten trioxide nanoparticles.  

PubMed

In this paper, we demonstrated a new convenient route for in situ fabrication of well separated small sized WO(3) nanoparticles in silica spheres, through a predeposition of surfactant encapsulated polyoxotungates as tungsten source, and followed by a calcination process. In a typical procedure, selected polyoxotungates with different charges were enwrapped with dioctadecyldimethylammonium cations through electrostatic interaction. Elemental analysis, thermogravimetric analysis, and spectral characterization confirmed the formation of prepared complexes with the anticipated chemical structure. The complexes were then phase-transferred into aqueous solution that predissolved surfactant cetyltrimethylammonium bromide, and finally incorporated into silica spheres through a joint sol-gel reaction with tetraethyl orthosilicate in a well dispersed state under the protection of organic layer for polyoxotungates from the alkaline reaction condition. Transmission electron microscopic images illustrated the well dispersed WO(3) nanoparticles in the size range of ca. 2.2 nm in the silica spheres after the calcination at 465 °C. The sizes of both the silica spheres and WO(3) nanoparticles could be adjusted independently through changing the doping content to a large extent. Meanwhile, the doped polyoxotungate complexes acted as the template for the mesoporous structure in silica spheres after the calcination. Along with the increase of doping content and surfactant, the mesopore size changed little (2.0-2.9 nm), but the specific surface areas increased quite a lot. Importantly, the WO(3)-nanoparticle-doped silica spheres displayed an interesting photovoltaic property, which is favorable for the funtionalization of these nanomaterials. PMID:20715875

Zhao, Yuanyuan; Fan, Haimei; Li, Wen; Bi, Lihua; Wang, Dejun; Wu, Lixin

2010-09-21

42

Incorporation of dopants into the lattice of ZnO nanoparticles to control photoactivity  

NASA Astrophysics Data System (ADS)

Using a similar production process, a series of doped and undoped ZnO nanoparticles has been tested for photoactivity, using chemical methods, when exposed to UV radiation. Parameters such as crystallite size, dopant type and concentration were considered. It was confirmed that photoactivity increased significantly by a factor of 2 to 3 as the mean crystallite size was decreased from 100 to 20 nm. Analysis of a further series of materials doped with metal cations showed that, depending on the dopant type and concentration, photoactivity could be reduced by more than an order of magnitude. A variant of the method of atom location by channelling-enhanced microanalysis (ALCHEMI) was applied to these crystal systems to determine whether or not dopant atoms at a concentration of less than 1 at.% were incorporated on the cation sublattice site within the nanoparticles. This technique is described and discussed in some detail.

Casey, P. S.; Rossouw, C. J.; Boskovic, S.; Lawrence, K. A.; Turney, T. W.

2006-01-01

43

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

PubMed

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

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

2013-01-01

44

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

NASA Astrophysics Data System (ADS)

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

Maver, Uroš; Bele, Marjan; Makovec, Darko; ?ampelj, Stanislav; Jamnik, Janko; Gaberš?ek, Miran

2009-10-01

45

Surface plasmon-enhanced electroluminescence in organic light-emitting diodes incorporating Au nanoparticles  

NASA Astrophysics Data System (ADS)

Surface plasmon-enhanced electroluminescence (EL) in an organic light-emitting diode is demonstrated by incorporating the synthesized Au nanoparticles (NPs) in the hole injection layer of poly(3,4-ethylene dioxythiophene):polystyrene sulfonic acid. An increase of ~25% in the EL intensity and efficiency are achieved for devices with Au NPs, whereas the spectral and electrical properties remain almost identical to the control device. Time-resolved photoluminescence spectroscopy reveals that the EL enhancement is ascribed to the increase in spontaneous emission rate due to the plasmonic near-field effect induced by Au NPs.

Xiao, Y.; Yang, J. P.; Cheng, P. P.; Zhu, J. J.; Xu, Z. Q.; Deng, Y. H.; Lee, S. T.; Li, Y. Q.; Tang, J. X.

2012-01-01

46

Incorporation of PLGA nanoparticles into porous chitosan-gelatin scaffolds: influence on the physical properties and cell behavior.  

PubMed

Bone regeneration can be accelerated by localized delivery of appropriate growth factors/biomolecules. Localized delivery can be achieved by a 2-level system: (i) incorporation of biomolecules within biodegradable particulate carriers (nanoparticles), and (ii) inclusion of such particulate carriers (nanoparticles) into suitable porous scaffolds. In this study, freeze-dried porous chitosan-gelatin scaffolds (CH-G: 1:2 ratio by weight) were embedded with various amounts of poly(lactide-co-glycolide) (PLGA) nanoparticles, precisely 16.6%, 33.3% and 66.6% (respect to CH-G weight). Scaffolds loaded with PLGA nanoparticles were subjected to physico-mechanical and biological characterizations including morphological analysis, swelling and dissolution tests, mechanical compression tests and cell viability tests. Results showed that incorporation of PLGA nanoparticles into porous crosslinked CH-G scaffolds: (i) changed the micro-architecture of the scaffolds in terms of mean pore diameter and pore size distribution, (ii) reduced the dissolution degree of the scaffolds, and (iii) increased the compressive modulus. On the other hand, the water uptake behavior of CH-G scaffolds containing PLGA nanoparticles significantly decreased. The incorporation of PLGA nanoparticles did not affect the biocompatibility of CH-G scaffolds. PMID:21783141

Nandagiri, Vijay Kumar; Gentile, Piergiorgio; Chiono, Valeria; Tonda-Turo, Chiara; Matsiko, Amos; Ramtoola, Zeibun; Montevecchi, Franco Maria; Ciardelli, Gianluca

2011-05-01

47

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

PubMed Central

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

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

2013-01-01

48

Preparation and characterization of selenium incorporated guar gum nanoparticle and its interaction with h9c2 cells.  

PubMed

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

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

2013-09-30

49

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

PubMed Central

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.

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

2008-01-01

50

Enhanced photocurrent and efficiency of poly(3-hexylthiophene)\\/fullerene photovoltaic devices by the incorporation of gold nanoparticles  

Microsoft Academic Search

We have investigated the role of gold nanoparticle incorporated in the bulk-heterojunction active layer of poly(3-hexylthiophene) (P3HT)\\/fullerene. Since the performance of this organic photovoltaic device is strongly related to the charge carrier transport mobility of bulk heterojunction that arises from the molecular ordering of P3HT semiconductor, we have set the range of nanoparticle concentration to the infinitesimal level, which does

Mira Park; Byung Doo Chin; Jae-Woong Yu; Myung-Suk Chun; Sung-Hwan Han

2008-01-01

51

Enhanced visualization of biodegradable polymeric vascular scaffolds by incorporation of gold, silver and magnetite nanoparticles.  

PubMed

Due to improved tissue regeneration and the enabling of post-operative minimally invasive interventions in the same vessel segment, biodegradable polymeric scaffolds represent a competitive approach to permanent metallic stents in vascular applications. Despite these advantages some challenges, such as the improvement of the scaffold mechanics and enhancement of scaffold visibility during the implantation procedure, are persisting. Therefore, the scope of our studies was to investigate the potential of gold, silver and magnetite nanoparticles incorporated in a polymeric blend of poly(L-lactide)/poly(4-hydroxybutyrate) for image enhancement in X-ray, magnetic resonance or near-infrared imaging. Their impact on mechanical properties of such modified scaffold materials was also evaluated. PMID:22492201

Luderer, Frank; Begerow, Ivonne; Schmidt, Wolfram; Martin, Heiner; Grabow, Niels; Bünger, Carsten M; Schareck, Wolfgang; Schmitz, Klaus-Peter; Sternberg, Katrin

2012-04-05

52

Three-Dimensional Model for Determining Inhomogeneous Thermal Dosage in a Liver Tumor During Arterial Embolization Hyperthermia Incorporating Magnetic Nanoparticles  

Microsoft Academic Search

Hyperthermia treatment incorporating magnetic nanoparticles (MNPs) is a hopeful therapy for cancers. Acquiring information about the MNPs' deposition in tumor tissues and modeling magnetic heating in vivo are essential for successful treatment. In this paper, we discuss the inhomogeneous heat generation by MNPs distributed heterogeneously in a liver tumor during arterial embolization hyperthermia (AEH) treatments. In order to more accurately

Ruizhi Xu; Hui Yu; Yu Zhang; Ming Ma; Zhongping Chen; Changling Wang; Gaojun Teng; Jun Ma; Xinchen Sun; Ning Gu

2009-01-01

53

Polylactide nanoparticles containing stably incorporated cyanine dyes for in vitro and in vivo imaging applications.  

PubMed

Stably incorporating fluorescent molecules to polymeric nanoparticles (NPs) or micelles can facilitate the prolonged tracking of these drug-delivery vehicles in vitro and in vivo. However, incorporation of fluorescent molecules, usually charged and thereby water-soluble, through the encapsulation strategy to hydrophobic polymer matrices is challenging. The encapsulated fluorescent agents are also subject to rapid release when the polymeric NPs are exposed to biological media. To address this issue, we developed Cy5-conjugated polylactide (Cy5-PLA) NPs through Cy5/(BDI)ZnN(TMS)2 [(BDI) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)-imino)-2-pentene]-mediated ring-opening polymerization of lactide (LA) followed by nanoprecipitation. This process allows for covalent conjugation of Cy5 to PLA with quantitative incorporation efficiency and formulation of Cy5-PLA NPs with controlled particles size (approximately 100 nm). As much as 80% of Cy5 was still present in the Cy5-PLA NPs after theses NPs were incubated in PBS at 37 degrees C for 12 days. Cy5-PLA NPs were conjugated to the A10 RNA aptamer that binds to the prostate-specific membrane antigen (PSMA). The resulting Cy5-PLA/aptamer NPs were found to only bind to and get internalized by LNCaP and canine prostate adenocarcinoma cells (PSMA-positive), but not to PC3 cells (PSMA-negative). The Cy5-PLA NPs were administered to balb/c mice intravenously and found to have excellent signals with low-background fluorescence in various organs. PMID:20146347

Tong, Rong; Coyle, Virginia J; Tang, Li; Barger, Anne M; Fan, Timothy M; Cheng, Jianjun

2010-09-01

54

Particular features of incorporation of coumarin 30 into nanoparticles from metal complexes and the intensity of its columinescence  

NASA Astrophysics Data System (ADS)

We have studied the sensitized fluorescence of coumarin 30 incorporated into nanoparticles from complexes of p-phenylbenzoyltrifluoroacetone and 1,10-phenanthroline with Y, La, Lu, Gd, Al, and Sc ions in 10% alcoholic-aqueous solutions. We have shown that, upon formation of nanoparticles from complexes of Y(III) and Ln(III) ions, coumarin 30 molecules are completely incorporated from the solution into nanoparticles from complexes up to dye concentrations in the solution comparable with the concentration complexes. For the nanoparticles under study, in the whole range of the examined dye concentrations, concentration quenching of the coumarin 30 cofluorescence has not been observed. Our results show that coumarin 30 is incorporated into lanthanide and yttrium complexes as a synergistic bidentate ligand. The possibility of creating brightly luminescent markers that absorb not only in the range of 360-370 nm, but also in the range of 440-450 nm, and have a narrow fluorescence spectrum with ?max = 520 nm has been demonstrated.

Sveshnikova, E. B.; Dudar', S. S.; Mironov, L. Yu.; Ermolaev, V. L.

2012-08-01

55

Doxorubicin-incorporated nanoparticles composed of poly(ethylene glycol)-grafted carboxymethyl chitosan and antitumor activity against glioma cells in vitro.  

PubMed

In this study, methoxy poly(ethylene glycol)-grafted carboxymethyl chitosan (CMCPEG) was synthesized to make nanoparticles with doxorubicin (DOX) by ion complex formation. Since DOX has positive amine groups, it can interact with the carboxymethyl group of CMCPEG. The particle size of DOX-incorporated nanoparticles of CMCPEG was < 300 nm and nanoparticles had spherical shapes at morphological observation, indicating that DOX/CMCPEG mixtures can form spherical nanoparticles. In a drug release study, higher drug content induced an extended release of drug. Drug release was significantly changed by the release media pH. DOX release was faster at an acidic pH than a neutral or basic pH. The antitumor activity of DOX-incorporated nanoparticles in vitro was tested with DOX-resistant C6 glioma cells. Nanoparticles showed increased cytotoxicity compared to DOX alone. These results suggest that DOX was unable to penetrate into cells and did not effectively inhibit cell proliferation. In contrast, nanoparticles can penetrate into cells and effectively inhibit cell proliferation. Observation of cells under red fluorescence confirmed these results, i.e., nanoparticle-treated C6 cells, unlike DOX-treated cells, had strong red fluorescence. Since DOX has strong red fluorescence, DOX-incorporated nanoparticles entered into the tumor cells more than DOX alone. As a result, we suggest that DOX-incorporated nanoparticles of CMCPEG are superior candidates for antitumor drug delivery. PMID:20427160

Jeong, Young-Il; Jin, Shu-Guang; Kim, In-Young; Pei, Jian; Wen, Min; Jung, Tae-Young; Moon, Kyung-Sub; Jung, Shin

2010-04-03

56

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

PubMed Central

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.

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

2009-01-01

57

The delivery of thrombi-specific nanoparticles incorporating oligonucleotides into injured cerebrovascular endothelium.  

PubMed

In acute vascular events, the endothelium derived tissue factor (TF) is the trigger of the coagulation cascade. In this study, EGFP-EGF1 protein-conjugated PEG-PLGA nanoparticle was employed as a TF targeting vehicle, the NF-?B decoy oligonucleotides (ODNs) was incorporated into it and the resulting EGF1-EGFP-NP-ODNs were evaluated as a vector for therapy of cortex infarction. At 2 h after transfection of TF expressed rat brain capillary endothelial cell, EGF1-EGFP-NP-ODNs was more efficiently internalized and located in the cytoplasm than NP-ODNs. At 4 h and 6 h after administration, ODNs were present in the nuclei and obviously inhibited the TF expression. At 6 h after i.v. administration in vivo, most EGF1-EGFP-NP were accumulated in the embolism vessels, distributed in the damaged endothelial cells and lowered the TF expression. At 24 h after i.v. administration, MR imaging of cortex infarcts were predominantly dwindled. PMID:23465828

Shi, Wei; Mei, Heng; Deng, Jun; Chen, Chen; Wang, Huafang; Guo, Tao; Zhang, Bo; Pang, Zhiqing; Jiang, Xinguo; Wang, Xuxia; Lei, Hao; Hu, Yu

2013-03-05

58

Incorporation of obidoxime into human serum albumin nanoparticles: optimisation of preparation parameters for the development of a stable formulation.  

PubMed

Intoxication with organophosphorous nerve agents such as paraoxon requires immediate administration of antidotes such as oximes. However, the oximes lack sufficient activity in the central nervous system as they are unable to rapidly penetrate the blood-brain barrier (BBB) in therapeutically relevant concentrations. Human serum albumin (HSA) nanoparticles represent a promising drug carrier system for the transport of drugs across the BBB. This study focussed on the development of an obidoxime-loaded nanoparticles prepared by desolvation using an incorporation technique. The nanoparticle preparation parameters, i.e. drug amount, pH value, ethanol volume and crosslinking degree, were optimised. The in vitro release study showed a sustained release profile, indicating the suitability of the developed formulation for the transport of oximes across the BBB. PMID:20923399

Kufleitner, Jürgen; Worek, Franz; Kreuter, Jörg

2010-01-01

59

Linear and nonlinear optical properties of KDP crystals with incorporated Al2O3?nH2O nanoparticles  

NASA Astrophysics Data System (ADS)

Optical and nonlinear optical properties of a novel composite system based on KDP single crystals with embedded nanoparticles of nanostructured oxyhydroxide of aluminum (Al2O3·nH2O, NOA), were studied. KDP crystals with NOA nanoparticles (KDP:NOA) possess high optical quality and homogeneity. Optical spectroscopy showed the presence of an absorption band at 270 nm caused by NOA nanoparticles incorporated in the KDP matrix. There was observed an enhancement of nonlinear refractive index and inversion of its sign in KDP:NOA crystals in comparison with nominally pure KDP crystals under excitation of picosecond laser pulses. The obtained results demonstrate that KDP:NOA is a promising composite material for optoelectronics and nonlinear optics.

Pritula, I. M.; Kosinova, A. V.; Bezkrovnaya, O. N.; Kolybaeva, M. I.; Puzikov, V. M.; Lopin, A. V.; Tkachenko, V. F.; Kopylovsky, M. A.; Yatsyna, V. O.; Gayvoronsky, V. Ya.

2013-10-01

60

Tracking the pathway of calcium phosphate\\/DNA nanoparticles during cell transfection by incorporation of red-fluorescing tetramethylrhodamine isothiocyanate–bovine serum albumin into these nanoparticles  

Microsoft Academic Search

Calcium phosphate nanoparticles were prepared by precipitation from water and were then functionalized by DNA. These particles\\u000a are taken up by living cells and function as gene transfer agents, i.e., the DNA is brought into a cell’s nucleus and is incorporated\\u000a there into the cell’s genome (transfection). DNA which encodes for enhanced green fluorescent protein leads to green fluorescence\\u000a of

Viktoriya Sokolova; Anna Kovtun; Rolf Heumann; Matthias Epple

2007-01-01

61

CCMR: Incorporating Surface Plasmons into Hybrid Core-Shell Fluorescent Silica Nanoparticles  

NSDL National Science Digital Library

Fluorescent silica nanoparticles are widely used in bioimaging, bioassay, and nanomedicine applications.[1] In such applications the control of fluorescence intensity is desirable. It is known that introducing a metallic particle or shell to such fluorescent silica nanoparticles can create a surface plasmon interaction between the metal and the fluorescent dye, potentially allowing for enhancement of the fluorescence intensity. This paper describes the synthesis of two types of hybrid nanoparticles with a fluorescent dye core-shell silica structure coated with small gold nanoparticles and a gold core surrounded by a silica shell of pure silica with Oregon green-488 dye in a second silica shell attached to the surface. The structure of these nanoparticles was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS), while their optical properties were investigated by spectrophotometry and fluorometry.

Belgrave, Akeisha

2007-08-29

62

Organic bulk heterojunction photovoltaic devices incorporating 2D arrays of cuboidal silver nanoparticles: Enhanced performance  

NASA Astrophysics Data System (ADS)

We have fabricated large-area arrays of two dimensional cuboidal silver nanoparticles on ITO substrates with good control over the coverage density using the Langmuir Blodgett technique and integrated them in functional plasmonic devices with P3HT and PCBM as photoactive layer. The results demonstrate that for device structures with 13.5% surface coverage of cuboidal silver nanoparticles, IPCE and PCE increased by 20% and ˜18% respectively. We attribute the improvements to enhanced absorption of the photoactive layer and an increase in exciton generation induced by strong local electric-field of the nanoparticles as well as an increased in the conductivity of the devices.

Leonard, Kwati; Takahashi, Yukina; You, Jing; Yonemura, Hiroaki; Kurawaki, Junichi; Yamada, Sunao

2013-10-01

63

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

PubMed

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

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

2013-07-29

64

The influence of incorporating organic molecules or inorganic nanoparticles on the optical and electrical properties of carbon nanotube films  

NASA Astrophysics Data System (ADS)

Organic molecules and inorganic nanoparticles were incorporated into transparent and conductive single- or double-wall carbon nanotube (SWNT or DWNT) films, and their electrical and optical properties were measured. When organic tetrafluoro-tetracyanoquinodimethane (F4TCNQ) molecules were incorporated into the nanotube films, sheet resistance was reduced to ˜50% of those from the pristine SWNT and DWNT films. Larger improvements were observed with Au nanoparticle decoration or HNO3/SOCl2 dipping processes. The sheet resistances were measured to be 42?/sq at 75% of transmittance for HNO3/SOCl2-treated DWNT films and 64?/sq at 77% for Au-incorporated DWNT films, making their electrical conductivities 200%-300% better than those of the pristine DWNT films. It was observed that DWNTs have better electrical/optical performance than SWNTs. The relative influence of various dopants, F4TCNQ, Au, and HNO3/SOCl2 as well as microwave irradiation on the optical and electrical properties was identified by using Raman and UV-vis-NIR spectra. Organic and inorganic nanomaterials were employed for p-type doping of carbon nanotube films. Doped double-wall nanotube films yielded high electrical conductivities up to ˜6×105 S/m. Excellent sheet resistance, 42?/sq at 75% of transmittance was observed. Microwave irradiation is suggested to create sites for doping.

Ryu, Yeontack; Yu, Choongho

2011-12-01

65

Interfacial Activity Assisted Surface Functionalization: A Novel Approach to Incorporate Maleimide Functional Groups and cRGD Peptide on Polymeric Nanoparticles for Targeted Drug Delivery  

PubMed Central

Nanoparticles formulated using poly(D,L-lactide-co-glycolide) (PLGA) copolymer have emerged as promising carriers for targeted delivery of a wide variety of payloads. However, an important drawback with PLGA nanoparticles is the limited types of functional groups available on the surface for conjugation to targeting ligands. In the current report, we demonstrate that the Interfacial Activity Assisted Surface Functionalization (IAASF) technique can be used to incorporate reactive functional groups such as maleimide onto the surface of PLGA nanoparticles. The surface maleimide groups were used to conjugate cRGD peptide to nanoparticles. The cRGD peptide targets ?v?3 integrins overexpressed on tumor vasculature and some tumor cells, and was used as model targeting ligand in this study. Incorporation of biologically active cRGD peptide on the surface of nanoparticles was confirmed by in vitro cell uptake studies and in vivo tumor accumulation studies. Functionalization of nanoparticles with cRGD peptide increased the cellular uptake of nanoparticles 2–3-fold, and this enhancement in uptake was substantially reduced by the presence of excess cRGD molecules. In a syngeneic mouse 4T1 tumor model, cRGD functionalization resulted in increased accumulation and retention of nanoparticles in the tumor tissue (nearly 2-fold greater area under the curve), confirming the in vivo activity of cRGD functionalized nanoparticles. In conclusion, the IAASF technique enabled the incorporation of reactive maleimide groups on PLGA nanoparticles, which in turn permitted efficient conjugation of biologically active cRGD peptide to the surface of PLGA nanoparticles.

Toti, Udaya S.; Guru, Bharath Raja; Grill, Alex E.; Panyam, Jayanth

2010-01-01

66

Sonoelectrochemical synthesis of highly photoelectrochemically active TiO2 nanotubes by incorporating CdS nanoparticles  

NASA Astrophysics Data System (ADS)

Self-organized anodic TiO2 nanotube arrays (TiO2NTs) are functionalized with CdS nanoparticle based perfusion and deposition through a single-step sonoelectrodeposition method. Even controlled at 50 °C, CdS nanoparticles with smaller size and more homogeneous distribution are successfully synthesized in dimethyl sulfoxide (DMSO) under ultrasonic irradiation. Moreover, TiO2 nanotubes can be filled with nanoparticles because of the ultrasonic effect. The CdS incorporated TiO2NTs (CdS-TiO2NTs) effectively harvest solar light in the UV as well as the visible light (up to 480 nm) region. Compared with pure TiO2NTs, a more than ninefold enhancement in photocurrent response is observed using the CdS-TiO2NTs. Maximum incident photon to charge carrier efficiency (IPCE) values of 99.95% and 9.85% are observed respectively for CdS-TiO2 nanotubes and pure TiO2NTs. The high value of IPCE observed with the CdS-TiO2NTs is attributed to the increased efficiency of charge separation and transport of electrons. A schematic diagram is proposed to illustrate the possible process of CdS formation in nanotubes under sonochemical and electrochemical conditions.

Wang, Cheng Lin; Sun, Lan; Yun, Hong; Li, Jing; Lai, Yue Kun; Lin, Chang Jian

2009-07-01

67

Mercury mobilization in a flooded soil by incorporation into metallic copper and metal sulfide nanoparticles.  

PubMed

Mercury is a highly toxic priority pollutant that can be released from wetlands as a result of biogeochemical redox processes. To investigate the temperature-dependent release of colloidal and dissolved Hg induced by flooding of a contaminated riparian soil, we performed laboratory microcosm experiments at 5, 14, and 23 °C. Our results demonstrate substantial colloidal Hg mobilization concomitant with Cu prior to the main period of sulfate reduction. For Cu, we previously showed that this mobilization was due to biomineralization of metallic Cu nanoparticles associated with suspended bacteria. X-ray absorption spectroscopy at the Hg LIII-edge showed that colloidal Hg corresponded to Hg substituting for Cu in the metallic Cu nanoparticles. Over the course of microbial sulfate reduction, colloidal Hg concentrations decreased but continued to dominate total Hg in the pore water for up to 5 weeks of flooding at all temperatures. Transmission electron microscopy (TEM) suggested that Hg became associated with Cu-rich mixed metal sulfide nanoparticles. The formation of Hg-containing metallic Cu and metal sulfide nanoparticles in contaminated riparian soils may influence the availability of Hg for methylation or volatilization processes and has substantial potential to drive Hg release into adjacent water bodies. PMID:23819689

Hofacker, Anke F; Voegelin, Andreas; Kaegi, Ralf; Kretzschmar, Ruben

2013-07-02

68

Effects of starch on nitrous acid-induced oxidation of kaempferol and inhibition of ?-amylase-catalysed digestion of starch by kaempferol under conditions simulating the stomach and the intestine.  

PubMed

Kaempferol glycosides can be hydrolyzed to their aglycone kaempferol during cooking under acidic conditions and in the oral cavity and the intestine by glycosidases. Kaempferol was oxidised by nitrite under acidic conditions (pH 2.0) to produce nitric oxide (NO), and the nitrite-induced oxidation of kaempferol was enhanced and inhibited by 10 and 100mg of starch ml(-1), respectively. The opposite effects of starch were discussed by considering the binding of kaempferol to starch and starch-dependent inhibition of the accessibility of nitrous acid to kaempferol. Kaempferol inhibited ?-amylase-catalysed starch digestion by forming starch/kaempferol complexes, and the inhibitory effects increased in the order of amylopectinkaempferol were discussed to be due to the difference in binding sites of kaempferol between amylose and amylopectin. From the present study, dual-function of kaempferol became apparent in the digestive tract. PMID:23768363

Takahama, Umeo; Hirota, Sachiko

2013-02-19

69

Molecular switch for the assembly of lipophilic drug incorporated plasma protein nanoparticles and in vivo image.  

PubMed

A strategy to manipulate the disulfide bond breaking triggered unfolding, and subsequently assembly of human serum albumin (HSA) in a lipophilic drug-dependent manner is present. In this study, the hydrophobic region, a molecular switch of the HSA, was regulated to form HSA-paclitaxel (HSA-PTX) nanoparticles by a facile route. High-resolution transmission electron microscopy and fluorescence quenching indicate that HSA coassembled with PTX, which acts as a bridge to form core-shell nanoparticles about 50-240 nm in size, and that PTX might bind to the subdomain IIA sites of HSA. Change of ultraviolet absorption and circular dichroism spectra reveal the formation of HSA-PTX nanoparticles, which is a safety, injectable pharmaceutic nanocarrier system for tumor target. This method to prepare nanocarrier systems for hydrophobic guest molecules reveals a general principle of self-assembly for other plasma proteins and other pharmacologically active substances with poor water solubility. It also provides a basis for developing nanocarrier systems for a wide range of applications in nanomedicine, from drug delivery to bioimaging systems. PMID:22029860

Gong, Guangming; Xu, Yan; Zhou, Yuanyuan; Meng, Zhengjie; Ren, Guoyan; Zhao, Yang; Zhang, Xiang; Wu, Jinhui; Hu, Yiqiao

2011-11-29

70

Cyclodextrins-Kaempferol Inclusion Complexes: Spectroscopic and Reactivity Studies  

Microsoft Academic Search

The slightly water-soluble flavonoid kaempferol (KAE) and its inclusion complexes with ?-cyclodextrin (?CD), hydroxypropyl-?-cyclodextrin (HP?CD) or heptakis-2,6-O-dimethyl-?-cyclodextrin (DM?CD) were investigated. The stoichiometric ratios and association constants describing the extent of the formation of the complexes\\u000a have been determined. Binding constants, estimated from fluorescence studies at different temperatures, were analyzed so as\\u000a to gain information about the mechanisms involved in the

Carolina Jullian; Victor Brossard; Iván Gonzalez; Muriel Alfaro; Claudio Olea-Azar

2011-01-01

71

Incorporation of zirconia nanoparticles into coatings formed on aluminium by AC plasma electrolytic oxidation  

Microsoft Academic Search

Composite ceramic coatings were formed on aluminium by AC plasma electrolytic oxidation (PEO) using Na6P6O18 or Na2SiO3 · 5H2O\\/KOH electrolytes with monoclinic zirconia nanoparticles in suspension. The coatings grown in Na2SiO3 · 5H2O\\/KOH electrolyte revealed ?-Al2O3 and amorphous phase; ?-Al2O3 and AlPO4 were additionally produced with the Na6P6O18 electrolyte. Higher temperature zirconia phases, possibly tetragonal and orthorhombic, in addition to the monoclinic phase,\\u000a were

E. Matykina; R. Arrabal; P. Skeldon; G. E. Thompson

2008-01-01

72

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

PubMed Central

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

2013-01-01

73

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

NASA Astrophysics Data System (ADS)

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

Liu, Kong; Qu, Shengchun; Zhang, Xinhui; Tan, Furui; Wang, Zhanguo

2013-02-01

74

Effect of different lipids and surfactants on formulation of solid lipid nanoparticles incorporating tamoxifen citrate  

PubMed Central

Tamoxifen Citrate (TC) is an estrogen receptor antagonist and drug of choice for hormone sensitive breast cancer. Solid Lipid Nanoparticles loaded with TC were prepared by High Shear Homogenization followed by Ultrasonication. The aim of the present work is to study the effect of four different Solid Lipids and three Surfactants on Formulation and Stability of SLN. They were characterized for Particle size, Polydispersity Index and Zeta Potential by Zetasizer Nano. SLN prepared by Solid Lipid Compritol 888 (Glyceryldibehenate) and Tween 80 (1%) showed desired Particle Size of 206.9 nm, PDI of 0.046 and Zeta Potential of 9.32 mV.

Upadhyay, S. U.; Patel, J. K.; Patel, V. A.; Saluja, A. K.

2012-01-01

75

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

76

Incorporation of precious metal nanoparticles into various aerogels by different supercritical deposition methods  

NASA Astrophysics Data System (ADS)

One major hurdle in nanoparticle fabrication is the difficulty in controlling size, distribution and concentration. Conventional methods in nanoparticle formation require high temperatures which lead to particle agglomeration and size broadening, or involve substantial amount of organic solvents. A clean route to supported-nanoparticles fabrication was investigated using various supercritical (SC) based deposition methods. The SC deposition involves the organometallic precursor (OP) (dimethyl(1,5-cyclooctadiene)platinum(II)[CODPtMe 2] or bis(2,2,6,6-tetramethyl-3,5-heptanedionato) (1,5-cyclooctadiene) ruthenium(II)) dissolution in SC fluid and contacting this solution with a substrate. The OP is adsorbed and subsequent reduction of the OP-impregnated substrate produces metal/substrate composites. The various methods were: (1) thermal reduction at atmospheric pressure in an inert atmosphere; (2) thermal reduction in SC carbon dioxide (scCO2); (3) chemical reduction in scCO2 with H2; and (4) chemical reduction at atmospheric pressure with H2. The synthesis of resorcinol-formaldehyde aerogels (RFAs) and carbon aerogels (CAs) was also studied and used as substrates (along with commercial silica aerogels (SAs)) in the SC deposition. The surface area, pore properties, and density of these aerogels were evaluated and the effects of reactant concentration, pyrolysis and SC deposition on these properties were determined. Using a static method, the adsorption isotherms of CODPtMe2 in scCO2 on two CAs with different pore sizes were measured at 28 MPa and 80°C to determine the maximum metal loading and the effect of pore properties on adsorption and to examine the interactions between the three components. The isotherms could be represented by the Langmuir model and the adsorption data indicated a strong CODPtMe2-CA interaction and that almost all the preexistent micropore area was covered with CODPtMe 2 molecules even at adsorption lower than the maximum capacity. The observed strong precursor-substrate interaction was corroborated by thermo-gravimetric analyses and N2 physisorption. Transmission electron microscopy, x-ray diffraction, H2 and CO chemisorption and N2 physisorption were employed to demonstrate the homogeneity of particle dispersion, to determine the morphology, range and variation in particle size within the solid matrices and to fully identify the resultant particles as Pt and Ru metals. (Abstract shortened by UMI.)

Saquing, Carl D.

77

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

PubMed

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 this biomaterial. As determined by scanning electron microscopy and urea permeability, the optimum NP size was estimated to be between 200 nm and 500 nm using commercial monodisperse latex spheres. The concentration of NPs that is required to alter pore sizes of SIS as determined by urea permeability was estimated to be 1 mg/ml 260 nm poly(lactic-co-glycolic) acid (PLGA) NPs. The 1mg/ml PLGA NPs loaded in the SIS did not change the tensile properties of the unmodified SIS or even alter pH values in a cell culture environment. More importantly, PLGA NP modified SIS did not affect human mammary endothelial cells (HMEC-1) morphology or adhesion, but actually enhanced HEMC-1 cell growth. PMID:18076986

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

2008-03-01

78

Polypropylene/Glass Fiber Hierarchical Composites Incorporating Inorganic Fullerene-like Nanoparticles for Advanced Technological Applications.  

PubMed

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

Díez-Pascual, Ana M; Naffakh, Mohammed

2013-09-23

79

Kaempferol 3,7,4'-glycosides from the flowers of Clematis cultivars.  

PubMed

A new kaempferol glycoside, kaempferol 3-O-alpha-rhamnopyranosyl-(1 --> 6)-beta-glucopyranoside-7,4'-di-O-beta-glucopyranoside (1) was isolated from the flowers of Clematis cultivars "Jackmanii Superba" and "Fujimusume", together with the known compound kaempferol 3,7,4'-tri-O-beta-glucopyranoside (2). The chemical structures of the isolated kaemferol glycosides were established by UV, 1H and 13C NMR spectroscopy, LC-MS, and characterization of acid hydrolysates. PMID:24079175

Sakaguchi, Keisuke; Kitajima, Junichi; Iwashina, Tsukasa

2013-08-01

80

Kaempferol inhibits cancer cell growth by antagonizing estrogen-related receptor ? and ? activities.  

PubMed

Kaempferol is a dietary flavonoid that can function as a selective estrogen receptor modulator (SERM). Estrogen-related receptors alpha and gamma (ERR? and ERR?) are orphan nuclear receptors that play important roles in mitochondrial biogenesis and cancer development. We have shown that kaempferol can functionally antagonize the activities of ERRs based on both response element reporter systems and target gene analysis. Kaempferol modulation of mitochondrial function and suppression cancer cell growth has been confirmed. These findings suggest that kaempferol may exert their anti-cancer activities through antagonizing ERRs activities. PMID:23852933

Wang, Haibin; Gao, Minghui; Wang, Junjian

2013-08-05

81

Flavonol kaempferol improves chronic hyperglycemia-impaired pancreatic beta-cell viability and insulin secretory function.  

PubMed

Considerable evidence shows that chronic hyperglycemia can cause pancreatic beta-cell dysfunction, which contributes to progressive deterioration of glucose homeostasis and overt diabetes. In the present study, we found that kaempferol, a flavonol compound present in various Chinese medicinal herbs, has cytoprotective effects on cultured clonal beta-cells and pancreatic human islets. Kaempferol treatment dose-dependently promoted viability, inhibited cellular apoptosis, and reduced caspase-3 activity in beta-cells and human islets exposed to chronic high glucose, with 10 ?M kaempferol exerting the maximum effect. In addition, kaempferol treatment improved the expression of anti-apoptotic proteins Akt and Bcl-2 that was significantly reduced in beta-cells and human islets chronically exposed to hyperglycemia. Furthermore, exposure of beta-cells and human islets to kaempferol restored high glucose-attenuated intracellular cAMP and ATP production. Inhibition of protein kinase A or Akt activation ablated the anti-apoptotic effect of kaempferol. These cytoprotective effects of kaempferol were associated with improved insulin secretory function and synthesis in beta-cells and human islets. These findings provide evidence that kaempferol may be a naturally occurring anti-diabetic compound by protecting pancreatic beta-cell survival and function in a hostile environment that would otherwise lead to type 2 diabetes. PMID:21914439

Zhang, Yanling; Liu, Dongmin

2011-09-02

82

Synergistic antiproliferative action of the flavonols quercetin and kaempferol in cultured human cancer cell lines.  

PubMed

The consumption of vegetables containing the flavonols quercetin and kaempferol reduces the risk of cancer. We utilized human gut (HuTu-80 and Caco-2) and breast cancer cells (PMC42) to show the synergistic effect of quercetin and kaempferol in reducing cell proliferation. A trend in reduction of total cell counts was seen following a single exposure, a 4-day exposure or a 14-day exposure to quercetin and kaempferol. Combined treatments with quercetin and kaempferol were more effective than the additive effects of each flavonol. The reduction in cell proliferation was associated with decreased expression of nuclear proliferation antigen Ki67 and decreased total protein levels in treated cells relative to controls. In conclusion, the synergistic antiproliferative effect of quercetin and kaempferol demonstrated in cultured human cells has broad implications for understanding the influence of dietary nutrients in vivo, where anticancer effects may be a result of nutrients which act in concert. PMID:15796157

Ackland, Margaret Leigh; van de Waarsenburg, Simone; Jones, Rod

83

Kaempferol glycosides from the twigs of Cinnamomum osmophloeum and their nitric oxide production inhibitory activities.  

PubMed

In the present study, ethanolic extract of twigs from Cinnamomum osmophloeum led to isolate nine kaempferol glycosides including two new kaempferol triglycosides that were characterized as kaempferol 3-O-?-D-xylopyranosyl-(1?2)-?-L-arabinofuranosyl-7-O-?-L-rhamnopyranoside (1) and kaempferol 3-O-?-D-xylopyranosyl-(1?2)-?-L-rhamnopyranosyl-7-O-?-L-rhamnopyranoside (2). The structures of these compounds were assigned by the application of 1D and 2D NMR spectroscopy and other techniques. Among these nine compounds, kaempferol 7-O-?-L-rhamnopyranoside (9) revealed inhibitory effect against LPS-induced production of nitric oxide in RAW 264.7 macrophages with an IC(50) value of 41.2 ?M. It also slightly reduced PGE(2) accumulation by 26% at the concentration of 50 ?M. PMID:23174526

Lin, Huan-You; Chang, Shang-Tzen

2012-10-22

84

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

85

Kaempferol Inhibits Angiogenesis and VEGF Expression Through Both HIF Dependent and Independent Pathways in Human Ovarian Cancer Cells  

Microsoft Academic Search

Ovarian cancer is 1 of the most significant malignancies in the Western world, and the antiangiogenesis strategy has been postulated for prevention and treatment of ovarian cancers. Kaempferol is a natural flavonoid present in many fruits and vegetables. The antiangiogenesis potential of kaempferol and its underlying mechanisms were investigated in two ovarian cancer cell lines, OVCAR-3 and A2780\\/CP70. Kaempferol mildly

Haitao Luo; Gary O. Rankin; Lingzhi Liu; Matthew K. Daddysman; Bing-Hua Jiang; Yi Charlie Chen

2009-01-01

86

In situ incorporation of nickel nanoparticles into the mesopores of MCM-41 by manipulation of solvent-solute interaction and its activity toward adsorptive desulfurization of gas oil.  

PubMed

In this contribution, different amounts of nickel were incorporated into the mesopores of MCM-41 via an in situ approach. A hydrophobic nickel precursor was incorporated into the nanochannels of mesoporous silica by manipulation of solvent-solute interaction. The synthesized material was characterized using X-ray diffraction, nitrogen physisorption, temperature programmed reduction, and transmission electron microscopy. The results implicate the formation of MCM-41 with well-ordered hexagonal structure and establish also the presence of nickel nanoparticles inside the nanochannels of mesoporous silica. Adsorptive desulfurization of gas oil was conducted using the nickel-incorporated MCM-41 samples. The effects of nickel concentration, temperature of process and feed flow rate on the desulfurization process were examined. The MCM-41 containing 6 wt.% of nickel had both the highest breakthrough sulfur adsorption capacity and total sulfur adsorption capacity, which were 0.69 and 1.67 mg sulfur/g adsorbent, respectively. The breakthrough sulfur adsorption capacity was almost regained after reductive regeneration of spent adsorbent. The obtained results suggest that the method applied for the synthesis of Niy/MCM resulted in formation of well-dispersed, accessible and small nickel nanoparticles incorporated into the pores of MCM-41 which might be an advantage for adsorption of refractory sulfur compounds from low sulfur gas oil. PMID:21820806

Samadi-Maybodi, Abdolraouf; Teymouri, Mohammad; Vahid, Amir; Miranbeigi, Aliakbar

2011-07-06

87

Stabilization of the Nitric Oxide (NO) Prodrugs and Anti-Cancer Leads, PABA/NO and Double JS-K through Incorporation into PEG-Protected Nanoparticles  

PubMed Central

Here we report the stabilization of the nitric oxide (NO) prodrugs and anti-cancer lead compounds, PABA/NO (O2-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) and “Double JS-K” (1,5-bis{[1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diol-2-ato]-2,4-dinitrobenzene), through their incorporation into polymer-protected nanoparticles. The prodrugs were formulated in block copolymer-stabilized nanoparticles with sizes from 220 to 450 nm by a novel rapid precipitation process. The block copolymers, with polyethylene glycol (PEG) soluble blocks, provide a steric barrier against NO prodrug activation by glutathione. Too rapid activation and NO release has been a major barrier to effective administration of this class of compounds. The nanoparticle stabilized PABA/NO from attack by glutathione as evidenced by a significant increase in time taken for 50% decomposition from 15 min (unformulated) to 5 h (formulated); in the case of Double JS-K, the 50% decomposition time was extended from 4.5 min (unformulated) to 40 min (formulated). The more hydrophobic PABA/NO produced more stable nanoparticles and correspondingly more extended release times in comparison with Double JS-K. The hydrophobic blocks of the polymer were either polystyrene or polylactide. Both blocks produced nanoparticles of approximately the same size and release kinetics. This combination of PEG-protected nanoparticles with sizes appropriate for cancer targeting by enhanced permeation and retention (EPR) and delayed release of NO may afford enhanced therapeutic benefit.

Kumar, Varun; Hong, Sam Y.; Maciag, Anna E.; Saavedra, Joseph E.; Adamson, Douglas H.; Prud'homme, Robert K.; Keefer, Larry K.; Chakrapani, Harinath

2009-01-01

88

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

Microsoft Academic Search

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

Ali Nazari

2011-01-01

89

Flavonol kaempferol improves chronic hyperglycemia-impaired pancreatic beta-cell viability and insulin secretory function  

Microsoft Academic Search

Considerable evidence shows that chronic hyperglycemia can cause pancreatic beta-cell dysfunction, which contributes to progressive deterioration of glucose homeostasis and overt diabetes. In the present study, we found that kaempferol, a flavonol compound present in various Chinese medicinal herbs, has cytoprotective effects on cultured clonal beta-cells and pancreatic human islets. Kaempferol treatment dose-dependently promoted viability, inhibited cellular apoptosis, and reduced

Yanling Zhang; Dongmin Liu

2011-01-01

90

Anti-oxidant activity and attenuation of bladder hyperactivity by the flavonoid compound kaempferol.  

PubMed

OBJECTIVES: To evaluate the anti-oxidant activity of the flavonoid compound, kaempferol, and to examine its role in the suppression of oxidative stress and attenuation of bladder hyperactivity in a rat model of bladder injury. METHODS: The anti-oxidative activity of kaempferol was examined in lipopolysaccharide-treated RAW264.7 macrophages by using flow cytometry. For in?vivo studies, rats were pretreated with kaempferol or vehicle for 24?h. The rat urothelium was injured by the administration of protamine sulfate for 1.5?h and irritated by the subsequent infusion of potassium chloride for 4?h. Oxidative stress in the bladder tissue was assessed using chemiluminescence assay, and the bladder pressure was determination by cystomertrogram. RESULTS: Kaempferol significantly suppressed lipopolysaccharide-induced reactive oxygen species production in RAW264.7 rat macrophages. Exposure of the rat bladder to sequential infusion of protamine sulfate and potassium chloride induced bladder hyperactivity. Pretreatment with kaempferol, prevented the formation of reactive oxygen species and prolonged the intercontraction interval. CONCLUSION: Kaempferol suppresses oxidative stress and attenuates bladder hyperactivity caused by potassium chloride after protamine sulfate-induced bladder injury. PMID:23634640

Huang, Yaw-Bin; Lin, Ming-Wei; Chao, Yun; Huang, Chi-Te; Tsai, Yi-Hung; Wu, Pao-Chu

2013-05-01

91

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

Microsoft Academic Search

Background  Short half-life and low levels of growth factors in the niche of injured microenvironment necessitates the exogenous and sustainable\\u000a delivery of growth factors along with stem cells to augment the regeneration of injured tissues.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Here, recombinant human hepatocyte growth factor (HGF) was incorporated into chitosan nanoparticles (CNP) by ionic gelation\\u000a method and studied for its morphological and physiological characteristics. Cirrhotic

Sivasami Pulavendran; Chellan Rose; Asit Baran Mandal

2011-01-01

92

Incorporation of silver nanoparticles into the bulk of the electrospun ultrafine polyimide nanofibers via a direct ion exchange self-metallization process.  

PubMed

This paper reports our works on the preparation of the silver-nanoparticle-incorporated ultrafine polyimide (PI) ultrafine fibers via a direct ion exchange self-metallization technique using silver ammonia complex cation ([Ag(NH(3))(2)](+)) as the silver precursor and pyromellitic dianhydride (PMDA)/4,4'-oxidianiline (4,4'-ODA) polyimide as the matrix. The polyimide precursor, poly(amic acid) (PAA), was synthesized and then electrospun into ultrafine fibers. By thermally treating the silver(I)-doped PAA ultrafine fibers, where the silver(I) ions were loaded through the ion exchange reactions of the carboxylic acid groups of the PAA macromolecules with the [Ag(NH(3))(2)](+) cations in an aqueous solution, ultrafine polyimide fibers embedded with silver nanoparticles with diameters less than 20 nm were successfully fabricated. The fiber-electrospinning process, the ion exchange process, and various factors influencing the hybrid ultrafine fibers preparation process such as the thermal treatment atmospheres and the thermal catalytic oxidative degradation effect of the reduced silver nanoparticles were discussed. The ultrafine fibers were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). PMID:22519411

Han, Enlin; Wu, Dezhen; Qi, Shengli; Tian, Guofeng; Niu, Hongqing; Shang, Gongping; Yan, Xiaona; Yang, Xiaoping

2012-05-04

93

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

Microsoft Academic Search

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

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

2008-01-01

94

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

SciTech Connect

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

Niering, Petra [Institute of Toxicology, Heinrich-Heine-University, PO Box 101007, 40001 Duesseldorf (Germany); Michels, Gudrun [Institute of Toxicology, Heinrich-Heine-University, PO Box 101007, 40001 Duesseldorf (Germany); Waetjen, Wim [Institute of Toxicology, Heinrich-Heine-University, PO Box 101007, 40001 Duesseldorf (Germany)]. E-mail: wim.waetjen@uni-duesseldorf.de; Ohler, Sandra [Institute of Toxicology, Heinrich-Heine-University, PO Box 101007, 40001 Duesseldorf (Germany); Steffan, Baerbel [Institute of Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, Universitaetsstrasse 1, 40225 Duesseldorf (Germany); Chovolou, Yvonni [Institute of Toxicology, Heinrich-Heine-University, PO Box 101007, 40001 Duesseldorf (Germany); Kampkoetter, Andreas [Institute of Toxicology, Heinrich-Heine-University, PO Box 101007, 40001 Duesseldorf (Germany); Proksch, Peter [Institute of Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, Universitaetsstrasse 1, 40225 Duesseldorf (Germany); Kahl, Regine [Institute of Toxicology, Heinrich-Heine-University, PO Box 101007, 40001 Duesseldorf (Germany)

2005-12-01

95

Nanomolar concentrations determination of hydrazine by a modified carbon paste electrode incorporating TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

In the present paper, the use of a carbon paste electrode modified by quinizarine (QZ) and TiO2 nanoparticles prepared by a simple and rapid method was described. The heterogeneous electron-transfer properties of quinizarine coupled to TiO2 nanoparticles at a carbon paste electrode was investigated using cyclic voltammetry and chronoamperometry in aqueous buffer solutions. The modified electrode showed excellent character for the electrocatalytic oxidization of hydrazine (HZ). Differential pulse voltammetric peak currents of HZ increased linearly with their concentrations at the range of 0.5 µM to 1900.0 µM and the detection limit (2?) was determined to be 77 nM. Finally, this method was used for the determination of HZ in water samples, using a standard addition method.

Mazloum-Ardakani, Mohammad; Taleat, Zahra; Beitollahi, Hadi; Naeimi, Hossein

2011-04-01

96

Kaempferol induces apoptosis in two different cell lines via Akt inactivation, Bax and SIRT3 activation, and mitochondrial dysfunction.  

PubMed

Kaempferol (3,4',5,7-tetrahydroxyflavone) is a flavonoid with anti- and pro-oxidant activity present in various natural sources. Kaempferol has been shown to posses anticancer properties through the induction of the apoptotic program. Here we report that treatment of the chronic myelogenous leukemia cell line K562 and promyelocitic human leukemia U937 with 50 microM kaempferol resulted in an increase of the antioxidant enzymes Mn and Cu/Zn superoxide dismutase (SOD). Kaempferol treatment induced apoptosis by decreasing the expression of Bcl-2 and increasing the expressions of Bax. There were also induction of mitochondrial release of cytochrome c into cytosol and significant activation of caspase-3, and -9 with PARP cleavage. Kaempferol treatment increased the expression and the mitochondria localization of the NAD-dependent deacetylase SIRT3. K562 cells stably overexpressing SIRT3 were more sensitive to kaempferol, whereas SIRT3 silencing did not increase the resistance of K562 cells to kaempferol. Inhibition of PI3K and de-phosphorylation of Akt at Ser473 and Thr308 was also observed after treating both K562 and U937 cells with kaempferol. In conclusion our study shows that the oxidative stress induced by kaempferol in K562 and U937 cell lines causes the inactivation of Akt and the activation of the mitochondrial phase of the apoptotic program with an increase of Bax and SIRT3, decrease of Bcl-2, release of cytochrome c, caspase-3 activation, and cell death. PMID:19160423

Marfe, Gabriella; Tafani, Marco; Indelicato, Manuela; Sinibaldi-Salimei, Paola; Reali, Valentina; Pucci, Bruna; Fini, Massimo; Russo, Matteo Antonio

2009-03-01

97

In vivo controlled release and prolonged antitumor effects of 2-methoxyestradiol solid lipid nanoparticles incorporated into a thermosensitive hydrogel.  

PubMed

A two-phase delivery system involving local injections of solid lipid nanoparticles (SLNs) -loaded hydrogel was developed using 2-methoxyestradiol as a model anticancer drug. This approach improves the effectiveness of conventional treatments for subcutaneous tumors and avoids that solid lipid nanoparticles are rapidly cleared from the circulation following systemic administration. The specific aim of the study presented in this article was to investigate the in vivo release, delivery and antitumor effects of 2-ME SLNs entrapped in a hydrogel. The results indicated that the hydrogel could deliver fluorescence-marked SLNs to tumor masses and cancer cells, exhibiting a controlled release of 2-ME SLNs over 46 days following a zero-order model. After treatment with the 2-ME SLN-loaded hydrogel, BALB/c mice that had been inoculated with syngeneic 4T1 breast cancer cells displayed significantly more tumor growth suppression for at least 21 days than those treated with a hydrogel containing the free drug, which was consistent with the in vitro cytotoxicity of 2-ME SLNs. This experiment demonstrated the efficacy of the hydrogel as a depot of 2-ME SLNs. Additionally, the mice treated with the hydrogel did not exhibit a loss of body weight or abnormal levels of white blood cells compared to the control group. These experiments demonstrated the potential value of 2-ME SLN hydrogel local injections as a safer and more effective method for the chemotherapy of subcutaneous tumors. PMID:22643052

Guo, XinHong; Xing, YaBing; Zhang, XinXin; Li, JunMei; Mei, Qian; Zhang, HongLing; Chen, ChengQun; Zhang, ZhenZhong; Cui, FuDe

2012-05-01

98

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

Microsoft Academic Search

BACKGROUND: Ovarian cancer is one of the most significant malignancies in the western world. Studies showed that Ovarian cancers tend to grow resistance to cisplatin treatment. Therefore, new approaches are needed in ovarian cancer treatment. Kaempferol is a dietary flavonoid that is widely distributed in fruits and vegetables, and epidemiology studies have revealed a protective effect of kaempferol against ovarian

Haitao Luo; Matthew K Daddysman; Gary O Rankin; Bing-Hua Jiang; Yi C Chen

2010-01-01

99

Specific features of absorption and DSC for the DEA-CuCl4 nanoparticles incorporated into the PMMA polymer matrices  

NASA Astrophysics Data System (ADS)

Diethylammonium tetrachlorcuprate NH2(C2H5)2CuCl4 (DEA-CuCl4) nanoparticles with sizes about 10 nm were synthesized and embedded into the PMMA polymer matrices. Using DSC temperature study a substantial influence of the polymer matrix on the phase transition temperatures was shown, reflecting a disturbing effect of principal 3d Cu 3p Cl metal ligand charge transfer bands. Dependence of the absorption spectra on the nanocrystallites (NC) concentration was studied. It was established that an increase of the NC content results in spectral shift of CuCl4 absorption bands. Explanation of this phenomenon has been suggested within a framework of first principle crystal field quantum chemical calculations.

Ozga, K.; Piasecki, M.; Tkaczyk, S.; Kapustianyk, B.; Bragiel, P.; Reshak, A. H.; Brik, M. G.; Kityk, I. V.

2008-08-01

100

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

PubMed

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

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

2010-06-30

101

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

PubMed Central

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.

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

2010-01-01

102

Potent inhibitory effect of naturally occurring flavonoids quercetin and kaempferol on in vitro osteoclastic bone resorption  

Microsoft Academic Search

Several recent studies have suggested that flavonols, a class of phytochemicals with many biological activities, might exert a protective effect against post-menopausal bone loss. In the present study, we investigated the effects of quercetin and kaempferol, two of the major naturally occurring flavonols on the in vitro bone resorbing activity of osteoclasts. Our results indicate that both compounds, at concentrations

Alice Wattel; Said Kamel; Romuald Mentaverri; Florence Lorget; Christophe Prouillet; Jean-Pierre Petit; Patrice Fardelonne; Michel Brazier

2003-01-01

103

Anti-free radical activities of kaempferol isolated from Acacia nilotica (L.) Willd. Ex. Del  

Microsoft Academic Search

In the present study the polyphenolic compound has been isolated from methanol extract of Acacia nilotica Willd. Ex. Del. which has been identified as kaempferol (AN-5) by NMR and mass spectroscopy. The antioxidant potential of the AN-5 was demonstrated in several in vitro assays: measuring the proton radical scavenging activity (DPPH scavenging assay), hydroxyl radical scavenging activity (deoxyribose degradation assay),

Rajbir Singh; Bikram Singh; Sukhpreet Singh; Neeraj Kumar; Subodh Kumar; Saroj Arora

2008-01-01

104

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

Microsoft Academic Search

BackgroundNew 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

Ting Zhang; Zhiqiang Wu; Jiang Du; Yongfeng Hu; Liguo Liu; Fan Yang; Qi Jin

2012-01-01

105

Antimicrobial and antioxidant activity of kaempferol rhamnoside derivatives from Bryophyllum pinnatum  

PubMed Central

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

2012-01-01

106

Determination of functionalized gold nanoparticles incorporated in hydrophilic and hydrophobic microenvironments by surface modification of quartz crystal microbalance  

NASA Astrophysics Data System (ADS)

In this study, plasma deposition methods were used to immobilize Au electrode of a quartz crystal microbalance (QCM) to create different microenvironments for mass measurement of various modified Au nanoparticles (AuNPs). AuNPs were modified by 11-mercaptoundecanoic acid (MUA) and 1-decanethiol (DCT) for potential applications to drug release, protective coatings, and immunosensors. We aimed to develop a highly sensitive and reliable method to quantify the mass of various modified AuNPs. The surface of AuNPs and Au electrode was coated with polymer films, as determined by Fourier transform infrared spectroscopy and atomic force microscopy. Measurements obtained for various AuNPs and the plasma-treated surface of the Au electrode were compared with those obtained for an untreated Au electrode. According to the resonant frequency shift of QCM, a linear relationship was observed that significantly differed for AuNPs, MUA-AuNPs, and DCT-AuNPs (R2 range, 0.94-0.965, 0.934-0.972, and 0.874-0.9514, respectively). Compared to inductively coupled plasma and micro-computerized tomography, the QCM method with plasma treatment has advantages of real-time monitoring, greater sensitivity, and lower cost. Our results demonstrate that surface modifications measured by a QCM system for various modified AuNPs were reliable.

Wu, Tsui-Hsun; Liao, Shu-Chuan; Chen, Ying-Fang; Huang, Yi-You; Wei, Yi-Syuan; Tu, Shu-Ju; Chen, Ko-Shao

2013-06-01

107

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

PubMed Central

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.

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

2006-01-01

108

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

SciTech Connect

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

Hong, J.-T. [Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Yen, J.-H. [Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien 970, Taiwan (China); Wang Lisu [Department of Food Science and Technology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Department of Environmental and Occupational Health, Medical College, Cheng-Kung University, Tainan 701, Taiwan (China); Lo, Y.-H. [Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Chen, Z.-T. [Department of Medicinal Chemistry, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China); Wu, M.-J. [Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan (China)], E-mail: imwu@mail.chna.edu.tw

2009-05-15

109

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

110

Inhibition of glucose intestinal absorption by kaempferol 3-O-?-rhamnoside purified from Bauhinia megalandra leaves.  

PubMed

Glucose intestinal absorption (GIA) is one of the factors that increase glycemia. Its reduction could be an important factor in decreasing hyperglycemia in diabetic patients. It has been shown that the aqueous extract of Bauhinia megalandra leaves inhibits GIA. In the present study we identified a compound present in the extract of B. megalandra responsible for the biological effect. The methanol extract of B. megalandra leaves was fractionated using different solvents, and high-speed counter-current chromatography yielding two pure compounds identified by (1)H NMR and (13)C NMR as kaempferol 3-O-?-rhamnoside and quercetin 3-O-?-rhamnoside. The first one increased the K(M) without changes in the V(MAX) of GIA. In addition it exerted an additive inhibitory effect, on GIA, when combined with phlorizin. We suggest that kaempferol 3-O-?-rhamnoside is a competitive inhibitor of intestinal SGLT1 cotransporter. PMID:20727952

Rodríguez, Patricia; González-Mujica, Freddy; Bermúdez, Jairo; Hasegawa, Masahisa

2010-08-18

111

Controlled, Defect-Guided, Metal-Nanoparticle Incorporation onto MoS2 via Chemical and Microwave Routes: Electrical, Thermal, and Structural Properties.  

PubMed

Ultrathin (0.3-3 nm) metal dichalcogenides exhibit confinement of carriers, evolution of band-structure and photophysical properties with thickness, high on/off rectification (in MoS2, WS2, and so forth) and high thermal absorption. Here, we leverage the stable sulfur/nobel-metal binding to incorporate highly capacitive gold nanoparticles (Au NPs) onto MoS2 to raise the effective gate-voltage by an order of magnitude. Functionalization is achieved via both diffusion limited aggregation and instantaneous reaction arresting (using microwaves) with selective deposition on crystallographic edges (with 60° displacement). The electrical, thermal, and Raman studies show a highly capacitive interaction between Au NP and MoS2 flakes (CAu-MoS2 = 2.17 ?F/cm(2)), a low Schottky barrier (14.52 meV), a reduced carrier-transport thermal-barrier (253 to 44.18 meV after Au NP functionalization), and increased thermal conductivity (from 15 to 23 W/mK post NP deposition). The process could be employed to attach electrodes to heterostructures of graphene and MoS2, where a gold film could be grown to act as an electron-tunneling gate-electrode connected to MoS2. PMID:23927716

Sreeprasad, T S; Nguyen, Phong; Kim, Namhoon; Berry, Vikas

2013-08-13

112

Quercetin, kaempferol and biapigenin from hypericum perforatum are neuroprotective against excitotoxic insults  

Microsoft Academic Search

In the present study we investigated the effects of phenolic compounds present inHypericum perforatum against neuronal excitotoxicity and mitochondrial dysfunction. Quercetin, kaemp-ferol and biapigenin significantly reduced\\u000a neuronal death caused by 100 ?M kainate plus 100 ?MN-methyl-D-aspartate. The observed neuroprotection was correlated with prevention of delayed calcium deregulation and with\\u000a the maintenance of mitochondrial transmembrane electric potential. The three compounds were

Bruno Silva; Paulo J. Oliveira; Alberto Dias; JOÃO O. Malva

2008-01-01

113

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

NASA Astrophysics Data System (ADS)

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

Matei, Iulia; Ionescu, Sorana; Hillebrand, Mihaela

2012-10-01

114

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

PubMed Central

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.

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

2010-01-01

115

Development of Inhalable Nanoparticles  

Microsoft Academic Search

The aim of this study was to develop nanoparticles for lung delivery. Nanoparticles were incorporated into carrier particles using spray drying and a new spray-freeze drying technology. The carrier particles were manufactured with the appropriate size for pulmonary delivery. The new technology has important implications for local drug targeting and drug delivery of nanoparticle based delivery systems to the lungs.

Leticia Ely; Raimar Löbenberg; Zhaolin Wang; Yu Zhang; Warren H. Finlay; Wilson H.-Y. Roa; Jeffrey O. H. Sham

2004-01-01

116

Production of quercetin, kaempferol and their glycosidic derivatives from the aqueous-organic extracted residue of litchi pericarp with Aspergillus awamori.  

PubMed

Our previous work exhibited Aspergillus awamori fermentation of the litchi pericarp increased significantly antioxidant activity and DNA protection effect. In this present study, the litchi pericarp and its aqueous-organic extracted residues were fermented by A. awamori in order to elucidate the enhanced beneficial effects. The study identified that rutin which present in litchi pericarp could be deglycosylated to form quercetin and quercetin-3-glucoside after the fermentation. Application the standard compounds (rutin, quercetin 3-glucoside, quercetin, kaempferol-3-glucoside and kaempferol) further revealed the effective biotransformation by A. awamori fermentation. It was hypothesised that rutin was initially dehydroxylated to form kaempferol-3-rutinoside and then deglycosylated to form kaempferol-3-glucoside and kaempferol. To our best knowledge, it is the first report on dehydroxylated effect of polyphenols caused by A. awamori fermentation. Thus, A. awamori fermentation can provide an effective way to produce health benefiting value-added products from litchi pericarp in food industry. PMID:24128471

Lin, Sen; Zhu, Qinqin; Wen, Lingrong; Yang, Bao; Jiang, Guoxiang; Gao, Haiyan; Chen, Feng; Jiang, Yueming

2013-08-22

117

Effect of kaempferol on lipid peroxidation and antioxidant status in 1,2-dimethyl hydrazine induced colorectal carcinoma in rats  

Microsoft Academic Search

Colorectal cancer, a common cause of cancer related deaths in both sexes in western population is often due to persistent oxidative stress leading to DNA damage. Antioxidants scavenge free radicals and inhibit neoplastic process. Kaempferol, a flavonol widely distributed in tea, broccoli, grape fruit, brussel sprouts and apple and is claimed to have chemopreventive action in colon cancer. The aim

Parthasarathy Nirmala; Manickam Ramanathan

2011-01-01

118

Kaempferol suppresses cell metastasis via inhibition of the ERK-p38-JNK and AP-1 signaling pathways in U-2 OS human osteosarcoma cells.  

PubMed

Kaempferol is a natural flavonoid that possesses anti-proliferative and apoptosis-inducing activities in several cancer cell lines. In the present study, we investigated the anti-metastatic activity of kaempferol and its molecular mechanism(s) of action in human osteosarcoma cells. Kaempferol displayed inhibitory effects on the invasion and adhesion of U-2 osteosarcoma (OS) cells in a concentration-dependent manner by Matrigel Transwell assay and cell adhesion assay. Kaempferol also inhibited the migration of U-2 OS cells in a concentration-dependent manner at different treatment time points by wound-healing assay. Additional experiments showed that kaempferol treatment reduced the enzymatic activities and protein levels of matrix metalloproteinase (MMP)-2, MMP-9 and urokinase plasminogen activator (uPA) by gelatin and casein-plasminogen zymography assays and western blot analyses. Kaempferol also downregulated the mRNA levels of MMP-2 and MMP-9 by quantitative PCR analyses. Furthermore, kaempferol was able to reduce the protein phosphorylation of ERK, p38 and JNK by western blotting. By electrophoretic mobility-shift assay (EMSA), we demonstrated that kaempferol decreased the DNA binding activity of AP-1, an action likely to result in the reduced expression of MMP-2, MMP-9 and uPA. Collectively, our data showed that kaempferol attenuated the MAPK signaling pathways including ERK, JNK and p38 and resulted in the decreased DNA binding ability of AP-1, and hence, the downregulation in the expression and enzymatic activities of MMP-2, MMP-9 and uPA, contributing to the inhibition of metastasis of U-2 OS cells. Our results suggest a potential role of kaempferol in the therapy of tumor metastasis of OS. PMID:23708932

Chen, Hui-Jye; Lin, Chung-Ming; Lee, Chao-Ying; Shih, Nai-Chen; Peng, Shu-Fen; Tsuzuki, Minoru; Amagaya, Sakae; Huang, Wen-Wen; Yang, Jai-Sing

2013-05-23

119

Effect of kaempferol on lipid peroxidation and antioxidant status in 1,2-dimethyl hydrazine induced colorectal carcinoma in rats.  

PubMed

Colorectal cancer, a common cause of cancer related deaths in both sexes in western population is often due to persistent oxidative stress leading to DNA damage. Antioxidants scavenge free radicals and inhibit neoplastic process. Kaempferol, a flavonol widely distributed in tea, broccoli, grape fruit, brussels sprouts and apple, is claimed to have chemopreventive action in colon cancer. The aim of our study was to evaluate the effect of kaempferol on tissue lipid peroxidation and antioxidant status in 1,2-dimethyl hydrazine induced colorectal cancer in male Wistar rats and to compare its efficacy with irinotecan. Experimental colon cancer induced by 1,2-dimethyl hydrazine in rats mimic human colon cancer and therefore is an ideal model for chemoprevention studies. The rats were divided into six groups. Group 1 served as control. Group 2 received 1,2-dimethyl hydrazine (20 mg/kg body weight) subcutaneously once a week for four weeks. Group 3 received irinotecan (100 mg/kg body weight) intravenously once a week for four weeks with 1,2-dimethyl hydrazine. Groups 4 to 6 were given a daily oral dose of 50, 100, 200 mg/kg body weight of kaempferol with 1,2-dimethyl hydrazine. The total study period was 16 weeks. Kaempferol supplementation lowered 1,2-dimethyl hydrazine induced erythrocyte lysate and liver thiobarbituric acid reactive substances level and rejuvenated anti oxidant enzymes catalase, super oxide dismutase and glutathione peroxidase. The recovery of enzyme status was maximum at the dose of 200 mg/kg body weight and was comparable to irinotecan. Our study reveals that kaempferol could be safely used as a chemopreventive agent in colorectal cancer. PMID:21172346

Nirmala, Parthasarathy; Ramanathan, Manickam

2010-12-21

120

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

Microsoft Academic Search

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

Cheng-Shane Chu; Yu-Lung Lo

2010-01-01

121

In situ incorporation of nickel nanoparticles into the mesopores of MCM-41 by manipulation of solvent–solute interaction and its activity toward adsorptive desulfurization of gas oil  

Microsoft Academic Search

In this contribution, different amounts of nickel were incorporated into the mesopores of MCM-41 via an in situ approach. A hydrophobic nickel precursor was incorporated into the nanochannels of mesoporous silica by manipulation of solvent–solute interaction. The synthesized material was characterized using X-ray diffraction, nitrogen physisorption, temperature programmed reduction, and transmission electron microscopy. The results implicate the formation of MCM-41

Abdolraouf Samadi-Maybodi; Mohammad Teymouri; Amir Vahid; Aliakbar Miranbeigi

2011-01-01

122

Kaempferol acts through mitogen-activated protein kinases and protein kinase B/AKT to elicit protection in a model of neuroinflammation in BV2 microglial cells  

PubMed Central

BACKGROUND AND PURPOSE Kaempferol, a dietary flavonoid and phyto-oestrogen, is known to have anti-inflammatory properties. Microglial activation has been implicated in various neurodegenerative diseases. Anti-inflammatory effects of kaempferol and the underlying mechanisms were investigated by using LPS-stimulated microglial BV2 cells. EXPERIMENTAL APPROACH Cell viability was measured using MTT and neutral red assays. elisa, Western blot, immunocytochemistry and electrophoretic mobility-shift assay were used to analyse NO, PGE2, TNF-? and IL-1? production, inducible NOS (iNOS), COX-2 expression and the involvement of signalling pathways such as toll-like receptor-4 (TLR4), MAPK cascades, PKB (AKT) and NF-?B. Accumulation of reaction oxygen species (ROS) was measured by nitroblue tetrazolium and 2?7?-dichlorofluorescein diacetate assay. Matrix metalloproteinase activity was investigated by zymography and immunoblot assay. Phagocytotic activity was assessed by use of latex beads. KEY RESULTS Kaempferol significantly attenuated LPS-induced NO, PGE2, TNF-?, IL-1? and ROS production and phagocytosis in a concentration-dependent manner. Kaempferol suppressed the expression of iNOS, COX-2, MMP-3 and blocked the TLR4 activation. Moreover, kaempferol inhibited LPS-induced NF-?B activation and p38 MAPK, JNK and AKT phosphorylation. CONCLUSION AND IMPLICATIONS Kaempferol was able to reduce LPS-induced inflammatory mediators through the down-regulation of TLR4, NF-?B, p38 MAPK, JNK and AKT suggesting that kaempferol has therapeutic potential for the treatment of neuroinflammatory diseases.

Park, SE; Sapkota, K; Kim, S; Kim, H; Kim, SJ

2011-01-01

123

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)

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.

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

2012-03-01

124

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

PubMed Central

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.

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

125

Identification and characterization of a novel kaempferol sulfotransferase from Arabidopsis thaliana.  

PubMed

In plants, flavonoids have been shown to be subjected to conjugation modifications such as glycosylation, methylation, and sulfation. Among these modifications, sulfation is known as an important pathway in the regulation of the levels of endogenous compounds such as steroids. Although a large variety of flavonoid sulfates also exist in plants, the detailed biochemical characterization of Arabidopsis thaliana sulfotransferases (AtSULTs) remains to be fully clarified. We report here that uncharacterized AtSULT202E1 (AGI code: At2g03770), a SULT202E subfamily member, shows the sulfating activity toward flavonoids. The general characteristics of the enzyme were studied on the optimum temperature and pH, the effect of divalent cations, and the thermal stability with kaempferol as substrate. A comparative analysis of the sulfation of flavonoids by AtSULT202E1, AtSULT202B1 and AtSULT202A1 revealed that three AtSULTs have differential substrate specificities. Surprisingly, 3-hydroxyflavone was sulfated only by AtSULT202A1 while 7-hydroxyflavone was highly sulfated by AtSULT202E1 and AtSULT202B1. These results indicate that flavonols might be sulfated in a position specific manner. In conclusion, our studies indicate that a novel AtSULT202E1 has the sulfating activity toward flavonoids together with AtSULT202B1 and AtSULT202A1. The existence of three flavonoid sulfotransferases in A. thaliana suggests that sulfation of flavonoids have an important role in regulation of their functions. PMID:23611783

Hashiguchi, Takuyu; Sakakibara, Yoichi; Hara, Yosuke; Shimohira, Takehiko; Kurogi, Katsuhisa; Akashi, Ryo; Liu, Ming-Cheh; Suiko, Masahito

2013-04-20

126

trans-[Ru(NO)Cl(cyclam)](PF6)2 and [Ru(NO)(Hedta)] Incorporated in PLGA Nanoparticles for the Delivery of Nitric Oxide to B16-F10 Cells: Cytotoxicity and Phototoxicity.  

PubMed

The immobilization and characterization of trans-[Ru(NO)Cl(cyclam)](PF6)2 (cyclam = 1,4,8,11-tetraazacyclotetradecane), and [Ru(NO)(Hedta)] (Hedta = ethylenediaminetetraacetic acid) entrapped in poly(d,l-lactic-co-glycolic) acid (PLGA) nanoparticles (NP) using the double emulsification process is described. Scanning electron microscopy and dynamic light scattering revealed that the particles are spherical in shape, have a size distribution between 220 and 840 nm of diameter, and have a tendency to aggregate confirmed by a zeta potential between -3.2 and +3.5 mV. Using this method the loading efficiency was 26% for trans-[Ru(NO)Cl(cyclam)](PF6)2 and 32% for [Ru(NO)(Hedta)]. The release of the complexes from the NPs shows that cyclam-NP and Hedta-NP exhibited a two-phase exponential association release pattern, which was characterized by an initial complex burst during the first 24 h, followed by a slower release phase complex profile, due to a few pores observed in surface of nanoparticles using atomic force microscopy. The in vitro cytotoxic activity of the nitrosyl complexes in solution and incorporated in PLGA nanoparticles on melanoma cancer cells (cell line B16-F10) was investigated. The lower cytotoxicity of trans-[RuCl(cyclam)(NO)](2+) (12.4 ± 2.6%) and [Ru(NO)(Hedta)] (4.0 ± 2.7%) in solution compared to that of trans-[Ru(NO)(NH3)4py](3+) (46.1 ± 6.4%) is consistent with the rate constant release of NO of these complexes (k-NO = 6.2 × 10(-4) s(-1), 2.0 × 10(-3) s(-1), and 6.0 × 10(-2) s(-1), respectively); the cytotoxicities are also inhibited in the presence of the NO scavenger carboxy-PTIO. The phototoxicity of these complexes is due to NO release, which lead to 53.8 ± 6.2% of cell death in the presence of trans-[Ru(NO)Cl(cyclam)](PF6)2 and 22.3 ± 5.1% in the presence of [Ru(NO)(Hedta)]. The PLGA nanoparticles loaded with trans-[Ru(NO)Cl(cyclam)](PF6)2 and [Ru(NO)(Hedta)] exerted in vitro a reduced activity against melanoma cells when compared to the activity of complex in solution (nonentrapped in nanoparticles). Blank PLGA nanoparticles did not exhibit cytotoxicity. In the presence of light and of ruthenium nitrosyl complexes or cyclam-NP and Hedta-NP, B16-F10 cells displayed a considerable damage of the surface with rupture of the plasma membrane. This behavior is an indicative of the efficiency of the DDS to deliver the NO from the entrapped complex when photoinduced. PMID:23865934

Gomes, Anderson J; Espreafico, Enilza M; Tfouni, Elia

2013-08-28

127

Quercetin and kaempferol suppress immunoglobulin E-mediated allergic inflammation in RBL-2H3 and Caco-2 cells  

Microsoft Academic Search

Objective  We investigated the inhibitory effects of quercetin and kaempferol treatment on the suppression of immunoglobulin E (IgE)-mediated\\u000a allergic responses in relation to intestinal epithelium barrier function in RBL-2H3 and Caco-2 cells.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  RBL-2H3 cells as a model of intestinal mucosa mast cells were treated with flavonols followed by IgE-anti-dinitrophenyl sensitization.\\u000a The extent of degranulation and the release of pro-inflammatory cytokines were

Eun-Ju Lee; Geun-Eok Ji; Mi-Kyung Sung

2010-01-01

128

Vascularization and bone regeneration in a critical sized defect using 2-N,6-O-sulfated chitosan nanoparticles incorporating BMP-2.  

PubMed

An ideal bone tissue engineering graft should have both excellent pro-osteogenesis and pro-angiogenesis to rapidly realize the bone regeneration in vivo. To meet this goal, 2-N,6-O-sulfated chitosan (26SCS) based nanoparticle (S-NP) was successfully developed and showed a dose-dependent enhancement on angiogenesis in vitro. For the repair of a critical sized defect in rabbit radius, we developed BMP-2 loaded S-NP (BMP-2/S-NP) with protein loading efficiency of 1.4 ± 0.2% and fabricated a gelatin sponge (G) based implant loaded with BMP-2/S-NP (BMP-2/S-NP/G). This implant exerted a delivery of BMP-2 with an initial burst release of 15.3 ± 4.1% in first 24 h and a gradual release for 21 days to 77.8 ± 3.6%. The in vitro ALP assay revealed that the activity of released BMP-2 from BMP-2/S-NP/G was maintained after 3-d and 7-d delivery and further enhanced after 14-d delivery compared with the original BMP-2. Furthermore, the in vivo effects of BMP-2/S-NP/G on the bone regeneration and vessel formation in the critical sized defect (18 mm) of rabbit radius were investigated by synchrotron radiation-based micro-computed tomography (SR?CT) imaging, three dimensional micro-computed tomographic (?CT) imaging, histological analysis, immunohistochemistry and biomechanical measurement. Based on the results, both peripheral vessel and new vessel formation were significantly increased by the BMP-2/S-NP/G treatment, along with the bridged defects at as early as 2 weeks, the healed defects at 8 weeks and the reunion of bone marrow cavity at 12 weeks. The results indicated that both controlled release of active BMP-2 and favorable vascularization at the defect site contributed by BMP-2/S-NP/G played a crucial role in accelerating and promoting bone augmentation. This study suggests that BMP-2/S-NP/G demonstrates promise for vascularization and bone regeneration in clinical case of large defect. PMID:24140042

Cao, Lingyan; Wang, Jing; Hou, Juan; Xing, Wanli; Liu, Changsheng

2013-10-18

129

Effects of solid dispersion and self-emulsifying formulations on the solubility, dissolution, permeability and pharmacokinetics of isorhamnetin, quercetin and kaempferol in total flavones of Hippophae rhamnoides L.  

PubMed

The aim of this study was to investigate the effects of solid dispersions (SD) and self-emulsifying (SE) formulations on the solubility and absorption properties of active components in total flavones of Hippophae rhamnoides L. (TFH). The solubility, dissolution rate, permeability and pharmacokinetics of isorhamnetin, quercetin and kaempferol in TFH SD/SE formulations and TFH were compared. The results showed that the solubility and dissolution rate of isorhamnetin, quercetin and kaempferol in SD/SE formulations were significantly enhanced compared to those in TFH, however, their intestinal permeability was comparable. The bioavailability of isorhamnetin, quercetin and kaempferol in rats remarkably increased after oral administration of TFH SD formulations compared to TFH, but there was no significant increase after oral administration of TFH SE formulations. The results of this study indicated the SD formulations on the improvement of pharmacokinetic properties of isorhamnetin, quercetin and kaempferol in TFH were much better than those of SE formulations. The improvement of pharmacokinetic properties of isorhamnetin, quercetin and kaempferol in TFH by SD formulations was probably ascribed to the enhancement of the solubility and dissolution of the three components, but was not relevant to the intestinal permeability. Therefore, as for herb extracts containing multiple components, especially for their major components with poor water solubility, solid dispersion formulations might have the better potential to enhance their bioavailability. PMID:22757776

Zhao, Guoying; Duan, Jingze; Xie, Yan; Lin, Guobei; Luo, Huilin; Li, Guowen; Yuan, Xiurong

2012-07-03

130

Engineering biofunctional magnetic nanoparticles for biotechnological applications  

Microsoft Academic Search

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

Maria Moros; Beatriz Pelaz; Pilar López-Larrubia; Maria L. García-Martin; Valeria Grazú; Jesus M. de La Fuente

2010-01-01

131

Palladium nanoparticle supported on cobalt ferrite: an efficient magnetically separable catalyst for ligand free Suzuki coupling  

Microsoft Academic Search

Synthesis of Pd nanoparticle supported on cobalt ferrite magnetic nanoparticles has been achieved by direct addition of Pd nanoparticles during synthesis of cobalt ferrite nanoparticles by ultrasound assisted co-precipitation in absence of any surface stabilizers or capping agent. The catalytic performance of the Pd incorporated cobalt ferrite nanoparticles was examined in Suzuki coupling reaction in ethanol under ligand free condition.

Kula Kamal Senapati; Subhasish Roy; Chandan Borgohain; Prodeep Phukan

132

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

NASA Astrophysics Data System (ADS)

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.

March, Raymond E.; Miao, Xiu-Sheng

2004-02-01

133

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

PubMed

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

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

2012-12-27

134

Kaempferol suppresses lipid accumulation in macrophages through the downregulation of cluster of differentiation 36 and the upregulation of scavenger receptor class B type I and ATP-binding cassette transporters A1 and G1.  

PubMed

The accumulation of foam cells in atherosclerotic lesions is a hallmark of early-stage atherosclerosis. Kaempferol has been shown to inhibit oxidized low-density lipoprotein (oxLDL) uptake by macrophages; however, the underlying molecular mechanisms are not yet fully investigated. In this study, we shown that treatment with kaempferol markedly suppresses oxLDL-induced macrophage foam cell formation, which occurs due to a decrease in lipid accumulation and an increase in cholesterol efflux from THP-1-derived macrophages. Additionally, the kaempferol treatment of macrophages led to the downregulation of cluster of differentiation 36 (CD36) protein levels, the upregulation of ATP-binding cassette (ABC) transporter A1 (ABCA1), scavenger receptor class B type I (SR-BI) and ABCG1 protein levels, while no effects on scavenger receptor A (SR-A) expression were observed. Kaempferol had similar effects on the mRNA and protein expression of ABCA1, SR-BI, SR-A, CD36 and ABCG1. The reduced CD36 expression following kaempferol treatment involved the inhibition of c-Jun-activator protein-1 (AP-1) nuclear translocation. The inhibition of AP-1 using the inhibitor, SP600125, confirmed this involvement, as the AP-1 inhibition significantly augmented the kaempferol-induced reduction in CD36 expression. Accordingly, the kaempferol-mediated suppression of lipid accumulation in macrophages was also augmented by SP600125. The increased expression of ABCA1, SR-BI and ABCG1 following kaempferol treatment was accompanied by the enhanced protein expression of heme oxygenase-1 (HO-1). This increase was reversed following the knockdown of the HO-1 gene using small hairpin RNA (shRNA). Moreover, the kaempferol-mediated attenuation of lipid accumulation and the promotion of cholesterol efflux was also inhibited by HO-1 shRNA. In conclusion, the c-Jun-AP?1-dependent downregulation of CD36 and the HO-1-dependent upregulation of ABCG1, SR-BI and ABCA1 may mediate the beneficial effects of kaempferol on foam cell formation. PMID:23232972

Li, Xiu-Ying; Kong, Ling-Xi; Li, Juan; He, Hai-Xia; Zhou, Yuan-Da

2012-12-05

135

Organic-Inorganic Hybrid Materials Based on the Incorporation of Polysilicic Acid Nanoparticle (PN) with Organic Polymers. 3. Shrinkage Characteristics in the Cure of Unsaturated Polyester Resin in the Presence of a Modified PN  

Microsoft Academic Search

The polysilicic acid nanoparticle (PN) was modified by the reaction of silanol group on its surface with silyl group (–Si(OR)3) containing modifiers such as phenyltrimethoxylsilane (PTS), 2-(p-styryl)ethyltrimethoxylsilane (SETS), and 3-(trimethoxylsilyl)propyl methacrylate (TPMA), respectively, to afford modified PNs (M-PNs) including P-PN, S-PN, and T-PN. P-PN, S-PN and T-PN were mixed, respectively, with unsaturated polyester resin (UP) in styrene, UP\\/St, and then

Y. G. Hsu; C. P. Wang

2003-01-01

136

Controlled Synthesis of Nanoparticles in Microheterogeneous Systems  

Microsoft Academic Search

Because of their structural and dynamical properties, microheterogeneous systems have been employed as solvent and reaction media both to synthesize and stabilize nanoparticles. Following this route, inside their nanometer-sized heterogeneities the nanoparticles of many different substances have been incorporated. The book shows the distinct advantages of this synthetic strategy over that of many other methods. Moreover, it furnishes to the

Vincenzo Turco Liveri

2006-01-01

137

Optical properties of Fe-doped SnO2 nanoparticles  

NASA Astrophysics Data System (ADS)

Pure and Fe-doped SnO2 nanoparticles were prepared in aqueous medium by wet chemical method. X-ray diffraction analysis revealed that Fe ions were incorporated into the SnO2 nanoparticles. The optical absorption and photoluminescence spectra of Fe-doped SnO2 nanoparticles show red shift compared that of pure SnO2 nanoparticles.

Sohila, S.; Rajalakshmi, M.; Muthamizhchelvan, C.; Kalavathi, S.

2012-06-01

138

Polyaniline\\/Silver Nanoparticle-Doped Multiwalled Carbon Nanotube Composites  

Microsoft Academic Search

A simple method was used to synthesize the hybrid nanocomposites consisting of the functionalized multiwalled carbon nanotube composites (MWCNTs) with the polyaniline incorporated silver nanoparticles (a-MWCNT\\/PANI-Ag) through an emulsion polymerization at room temperature in order to enhance the electrical conductivity of polyaniline. The electrical conductivity of the composite with the incorporated Ag nanoparticles was 5% higher than the same weight

Ali Grinou; Hyeonseong Bak; Young Soo Yun; Hyoung-Joon Jin

2012-01-01

139

Polyaniline\\/Silver Nanoparticle-Doped Multiwalled Carbon Nanotube Composites  

Microsoft Academic Search

A simple method was used to synthesize the hybrid nanocomposites consisting of the functionalized MWCNTs with the polyaniline incorporated silver nanoparticles (a-MWCNT\\/PANI-Ag) through an emulsion polymerization at room temperature in order to enhance the electrical conductivity of polyaniline. The electrical conductivity of the composite with the incorporated Ag nanoparticles was 5% higher than the same weight percent for the composite

Ali Grinou; Hyeonseong Bak; Young Soo Yun; Hyoung-Joon Jin

2011-01-01

140

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...

141

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...

142

Nanoparticle PEGylation for imaging and therapy  

PubMed Central

Nanoparticles are an essential component in the emerging field of nanomedical imaging and therapy. When deployed in vivo, these materials are typically protected from the immune system by polyethylene glycol (PEG). A wide variety of strategies to coat and characterize nanoparticles with PEG has established important trends on PEG size, shape, density, loading level, molecular weight, charge and purification. Strategies to incorporate targeting ligands are also prevalent. This article presents a background to investigators new to stealth nanoparticles, and suggests some key considerations needed prior to designing a nanoparticle PEGylation protocol and characterizing the performance features of the product.

Jokerst, Jesse V; Lobovkina, Tatsiana; Zare, Richard N; Gambhir, Sanjiv S

2011-01-01

143

Quercetin and kaempferol 3-O-[?-L-rhamnopyranosyl-(1?2)-?-L-arabinopyranoside]-7-O-?-L-rhamnopyranosides from Anthyllis hermanniae: structure determination and conformational studies.  

PubMed

The study reports the isolation and structural identification of two new flavonol triglycosides from the methanolic extract of Anthyllis hermanniae, exhibiting the same glycosylation pattern: quercetin 3-O-[?-L-rhamnopyranosyl-(1?2)-?-L-arabinopyranoside]-7-O-?-L-rhamnopyranoside (1) and kaempferol 3-O-[?-L-rhamnopyranosyl-(1?2)-?-L-arabinopyranoside]-7-O-?-L-rhamnopyranoside (2). A conformational study related to the central arabinoside moiety was carried out including the analysis of the contribution of NOE effects and acetylation to the elucidation of the 2-O-linked arabinoside configuration of the anomeric carbon. We also report the total synthesis of a model compound, quercetin 3-O-?-L-rhamnopyranosyl-(1?2)-?-L-arabinopyranoside (3), which verifies the structures of the isolated compounds. PMID:21861458

Halabalaki, Maria; Urbain, Aurélie; Paschali, Aristea; Mitakou, Sofia; Tillequin, François; Skaltsounis, Alexios-Leandros

2011-08-23

144

Fabrication, characterization and microwave properties of polyurethane nanocomposites reinforced with iron oxide and barium titanate nanoparticles  

Microsoft Academic Search

Polyurethane (PU) nanocomposites reinforced with magnetic iron oxide nanoparticles and\\/or dielectric barium titanate nanoparticles fabricated by the surface-initiated-polymerization approach were investigated. The polymer matrix incorporated with different nanoparticles shows different presenting status surrounding the nanoparticles, i.e., chemical bonding, physical entanglement and bulk polymer chain. The nanoparticles have a different effect on the thermal stability of the polymer nanocomposites. By embedding

Z. Guo; S.-E. Lee; H. Kim; H. T. Hahn; A. B. Karki; D. P. Young

2009-01-01

145

Preparation, characterization, and in vivo evaluation of mitoxantrone-loaded, folate-conjugated albumin nanoparticles  

Microsoft Academic Search

Folic acid was covalently conjugated to bovine serum albumin nanoparticles (BSANP) to target the nanoparticles to SKOV3 cells\\u000a expressing folate receptors. Mitoxantrone was incorporated into the folate-conjugated albumin nanoparticles, and the final\\u000a nanoparticle size was 68 nm, as measured by a laser light scattering particle analyzer. The cytotoxic activity of mitoxantrone-\\u000a loaded, folate-conjugated albumin nanoparticles (MTO-BSANP-folate), which was quantitated by

Liang-ke Zhang; Shi-xiang Hou; Jing-qin Zhang; Wen-jing Hu; Cheng-yuan Wang

2010-01-01

146

Albumin nanoparticles improved the stability, nuclear accumulation and anticytomegaloviral activity of a phosphodiester oligonucleotide  

Microsoft Academic Search

The goal of this study was to evaluate the potential of albumin nanoparticles as a delivery system for antisense oligonucleotides. Nanoparticles were prepared by a coacervation process and cross-linkage with glutaraldehyde. Phosphodiester (PO) and phosphorotioate (PS) oligonucleotides were either adsorbed on the surface of nanoparticles (PO-NPA and PS-NPA) or incorporated in the nanoparticle matrix (PO-NPB and PS-NPB). When PO-loaded nanoparticles

A. Arnedo; J. M. Irache; M. Merodio; M. S. Espuelas Millán

2004-01-01

147

Application of Magnetic Nanoparticles to Gene Delivery  

PubMed Central

Nanoparticle technology is being incorporated into many areas of molecular science and biomedicine. Because nanoparticles are small enough to enter almost all areas of the body, including the circulatory system and cells, they have been and continue to be exploited for basic biomedical research as well as clinical diagnostic and therapeutic applications. For example, nanoparticles hold great promise for enabling gene therapy to reach its full potential by facilitating targeted delivery of DNA into tissues and cells. Substantial progress has been made in binding DNA to nanoparticles and controlling the behavior of these complexes. In this article, we review research on binding DNAs to nanoparticles as well as our latest study on non-viral gene delivery using polyethylenimine-coated magnetic nanoparticles.

Kami, Daisuke; Takeda, Shogo; Itakura, Yoko; Gojo, Satoshi; Watanabe, Masatoshi; Toyoda, Masashi

2011-01-01

148

Engineering biofunctional magnetic nanoparticles for biotechnological applications  

NASA Astrophysics Data System (ADS)

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

Moros, Maria; Pelaz, Beatriz; López-Larrubia, Pilar; García-Martin, Maria L.; Grazú, Valeria; de La Fuente, Jesus M.

2010-09-01

149

A tough nanofiber hydrogel incorporating ferritin  

NASA Astrophysics Data System (ADS)

We have developed tough nanofiber hydrogels incorporating ferritin nanoparticles with a core-shell structure that is suitable for stress concentration reduction. The swelling properties of the nanocomposite hydrogel under external forces were enhanced, leading to fast water absorption. The elastic modulus, tensile strength, and elongation at break of the nanocomposite hydrogel measured in solutions were dramatically enhanced as compared to those of the bare polymer hydrogel. During the tensile tests, the strong bonding between the nanofiller and polymer matrix played an important role in enhancing the toughness of the composite hydrogel fibers.

Shin, Min Kyoon; Kim, Sun I.; Kim, Seon Jeong; Kim, Byung Joo; So, Insuk; Kozlov, Mikhail E.; Oh, Jiyoung; Baughman, Ray H.

2008-10-01

150

Enhanced antiviral activity of acyclovir loaded into nanoparticles.  

PubMed

The activity of antivirals can be enhanced by their incorporation in nanoparticulate delivery systems. Peculiar polymeric nanoparticles, based on a ?-cyclodextrin-poly(4-acryloylmorpholine) monoconjugate (?-CD-PACM), are proposed as acyclovir carriers. The experimental procedure necessary to obtain the acyclovir-loaded nanoparticles using the solvent displacement preparation method will be described in this chapter. Fluorescent labeled nanoparticles are prepared using the same method for cellular trafficking studies. The biocompatibility assays necessary to obtain safe nanoparticles are reported. Section 4 of this chapter describes the assessment of the antiviral activity of the acyclovir-loaded nanoparticles. PMID:22568898

Cavalli, Roberta; Donalisio, Manuela; Bisazza, Agnese; Civra, Andrea; Ranucci, Elisabetta; Ferruti, Paolo; Lembo, David

2012-01-01

151

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 ...

152

Fluorescent Nanoparticles  

NSDL National Science Digital Library

This site from Clemson University shows how fluorescence enables the tracking of nanoparticles in living cells. Illustrations include the fluorescence of different kinds of nanoparticles, close-up views of the fluorescent particles, and the fluorescent particles as seen within cells.

Mcneill, Jason

2008-04-16

153

Electrophoretic Deposition of Thin Films of Nanoparticles  

NASA Astrophysics Data System (ADS)

Nanoparticles have attracted considerable interest recently due to their size-dependent, quantum confinement characteristics, which make them attractive for an array of optical, magnetic, and electronic devices. For nanoparticles to be employed in an array of commercial and industrial applications, a technique for the facile, site-selective assembly of homogeneous, densely packed, defect-free thin films must be realized. Widely used methods for casting nanoparticle (NP) constituents into films have recognized limitations, including the inability to achieve both large-scale ordering of the nanoparticles and robust chemical and structural properties. NP deposition schemes also require an understanding of both the NP dynamics in suspension and the interactions that govern nanoparticle-substrate and nanoparticle-nanoparticle binding. Although research has been conducted on the assembly of nanoparticles with a distribution of surface charge states, little has been done on the assembly of like-charged nanoparticles. The only NP deposition scheme that considers the physical characteristics of the NPs in the film formation and incorporates the most favorable attributes of NP deposition is electrophoretic deposition (EPD). Recent progress in the NP EPD will be the emphasis of this presentation. Highlighted are the recent discoveries of the size dependence of the thickness of iron oxide NP films and the fabrication of free-standing NP films.

Dickerson, James

2008-10-01

154

Metal oxide nanoparticles for advanced energy applications  

Microsoft Academic Search

Hot-wire chemical vapor deposition (HWCVD) has been employed as an economically scalable method for the deposition of crystalline molybdenum oxide nanoparticles at high density. Under optimal synthesis conditions, only crystalline nanostructures with a smallest dimension of ~3–50 nm are observed with extensive transmission electron microscopy analyses. The incorporation of crystalline molybdenum oxide nanoparticles into battery electrodes has led to profound advancements

Se-Hee Lee; Rohit. Deshpande; Daniel Benhammou; Phil A. Parilla; A. Harv Mahan; Anne C. Dillon

2009-01-01

155

Guide to Self, Incorporated.  

ERIC Educational Resources Information Center

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

Christopher, Lochie B.; Harrelson, Orvis A.

156

Design and characterization of protein-quercetin bioactive nanoparticles  

PubMed Central

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.

2011-01-01

157

Mechanistic study of the adjuvant effect of biodegradable nanoparticles in mucosal vaccination  

Microsoft Academic Search

For oral vaccination, incorporation of antigens into nanoparticles has been shown to protect the antigen from degradation, but may also increase its uptake through the intestinal epithelium via M-cells. The aim of this study was to understand the mechanisms by which oral administration of antigen-loaded nanoparticles induces an immune response and to analyze the effect of the nanoparticle composition on

Bram Slütter; Laurence Plapied; Virgine Fievez; Maria Alonso Sande; Anne des Rieux; Yves-Jacques Schneider; Elly Van Riet; Wim Jiskoot; Véronique Préat

2009-01-01

158

Influence of nanoparticle surface treatment on the electrical properties of cycloaliphatic epoxy nanocomposites  

Microsoft Academic Search

This experimental study reports the influence of the surface treatment of silica nanoparticles on the morphology and electrical properties of epoxy composites. (3-Glycidoxypropyl)methyldiethoxysilane was used as a silane coupling agent for the surface treatment of the silica nanoparticles. It was found that the incorporation of the silane onto the surface of silica nanoparticles not only improved the dispersion of the

Xingyi Huang; Yun Zheng; Pingkai Jiang; Yi Yin

2010-01-01

159

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...

160

AC plasma electrolytic oxidation of magnesium with zirconia nanoparticles  

Microsoft Academic Search

The incorporation of monoclinic zirconia nanoparticles and their subsequent transformation is examined for coatings formed on magnesium by plasma electrolytic oxidation under AC conditions in silicate electrolyte. The coatings are shown to comprise two main layers, with nanoparticles entering the coating at the coating surface and through short-circuit paths to the region of the interface between the inner and outer

R. Arrabal; E. Matykina; F. Viejo; P. Skeldon; G. E. Thompson; M. C. Merino

2008-01-01

161

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  

Microsoft Academic Search

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

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

2011-01-01

162

Superparamagnetic Nanoparticles  

Microsoft Academic Search

\\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

Boon Hoong Ong; Nisha Kumari Devaraj

163

Characterizing nanoparticles  

NASA Astrophysics Data System (ADS)

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

Perrey, Christopher Robert

164

Biocompatibility of crystalline opal nanoparticles  

PubMed Central

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.

2012-01-01

165

Polymeric Nanoparticles for siRNA Delivery and Gene Silencing  

PubMed Central

Gene silencing using small interfering RNA (siRNA) has several potential therapeutic applications. In the present study, we investigated nanoparticles formulated using the biodegradable polymer, poly(d,l-lactide-co-glycolide) (PLGA) for siRNA delivery. A cationic polymer, polyethylenimine (PEI), was incorporated in the PLGA matrix to improve siRNA encapsulation in PLGA nanoparticles. PLGA-PEI nanoparticles were formulated using double emulsion-solvent evaporation technique and characterized for siRNA encapsulation and in vitro release. The effectiveness of siRNA-loaded PLGA-PEI nanoparticles in silencing a model gene, fire fly luciferase, was investigated in cell culture. Presence of PEI in PLGA nanoparticle matrix increased siRNA encapsulation by about 2-fold and also improved the siRNA release profile. PLGA-PEI nanoparticles carrying luciferase-targeted siRNA enabled effective silencing of the gene in cells stably expressing luciferase as well as in cells that could be induced to overexpress the gene. Quantitative studies indicated that presence of PEI in PLGA nanoparticles resulted in 2-fold higher cellular uptake of nanoparticles while fluorescence microscopy studies showed that PLGA-PEI nanoparticles delivered the encapsulated siRNA in the cellular cytoplasm; both higher uptake and greater cytosolic delivery could have contributed to the gene silencing effectiveness of PLGA-PEI nanoparticles. Serum stability and lack of cytotoxicity further add to the potential of PLGA-PEI nanoparticles in gene silencing-based therapeutic applications.

Patil, Yogesh; Panyam, Jayanth

2009-01-01

166

Nonsolvents-induced swelling of poly(methyl methacrylate) nanoparticles.  

PubMed

Polymer nanoparticles have been used in a wide variety of applications. In most of these applications, they are generally dispersed in a non-solvent. However, the effect of the non-solvent on the structure, physical properties and function of the nanoparticles has not yet ever taken into account. In this study, monodispersed poly(methyl methacrylate) (PMMA) nanoparticles were prepared by a surfactant-free emulsion polymerization. The PMMA nanoparticles were dispersed in water and in methanol, both typical non-solvents for PMMA, so that we could discuss the effect of the non-solvent on the nanoparticles. Dynamic light scattering measurements revealed that the hydrodynamic radius of the PMMA nanoparticles in methanol was larger than the same PMMA dispersed in water. Their DLS values were also larger than the radius of the nanoparticles measured by atomic force microscopy. When pyrene was dispersed in methanol with the PMMA nanoparticles, it was incorporated into the nanoparticles. These results clearly indicate that non-solvent molecules can be sorbed into polymer nanoparticles because the area of the interface, where polymer segments might be dissolved into liquid phases, as the total volume is quite larger for such nanoparticles. Therefore, based on our findings, it can be arguably established that the present assumption for a polymer not to be swollen in its non-solvent is not necessarily true. PMID:23955567

Shundo, Atsuomi; Hori, Koichiro; Penaloza, David P; Yoshihiro, Kazuki; Annaka, Masahiko; Tanaka, Keiji

2013-08-16

167

Hybrid nanoparticles for detection and treatment of cancer.  

PubMed

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

Sailor, Michael J; Park, Ji-Ho

2012-05-21

168

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

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

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

2011-01-28

169

Apoferritin-Templated Synthesis of Encoded Metallic Phosphate Nanoparticle Tags  

SciTech Connect

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.

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

2007-07-31

170

Nanoparticle-directed self-assembly of amphiphilic block-copolymers  

NASA Astrophysics Data System (ADS)

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.

Park, So-Jung

2011-03-01

171

Synthesis of atypical nanoparticles by the nanostructure in thin films of triblock copolymers.  

PubMed

We report the synthesis of atypical nanoparticles in donut shape with or without additional spherical nanoparticles attached on them by using the donut-like nanostructure formed in a thin film of triblock copolymers. In a high-humidity condition, a spin-coated film of triblock copolymer had donut-like holes consisting of the periphery and the center. By selective coordination of precursors of nanoparticles to the periphery of the holes, donut-like oxide nanoparticles were synthesized by oxygen plasma treatment on the film. Moreover, we were able to attach spherical nanoparticles on the donut-like nanoparticles by incorporating the other type of precursors to the center of the holes. Thus, beyond the synthesis of typical spherical nanoparticles, the results here extend potentials of the block copolymer approach to control the shape and complexity of nanoparticles. PMID:18729492

Jeon, Seung-Min; Jang, Kyo-Young; Lee, Sung Hwa; Park, Hae-Woong; Sohn, Byeong-Hyeok

2008-08-27

172

Drug targeting by solid lipid nanoparticles for dermal use.  

PubMed

Long term topical glucocorticoid treatment can induce skin atrophy by the inhibition of fibroblasts. We, therefore, looked for the newly developed drug carriers that may contribute to a reduction of this risk by an epidermal targeting. Prednicarbate (PC, 0.25%) was incorporated into solid lipid nanoparticles of various compositions. Conventional PC cream of 0.25% and ointment served for reference. Local tolerability as well as drug penetration and metabolism were studied in excised human skin and reconstructed epidermis. With the latter drug recovery from the acceptor medium was about 2% of the applied amount following PC cream and ointment but 6.65% following nanoparticle dispersion. Most interestingly, PC incorporation into nanoparticles appeared to induce a localizing effect in the epidermal layer which was pronounced at 6 h and declined later. Dilution of the PC-loaded nanoparticle preparation with cream (1:9) did not reduce the targeting effect while adding drug-free nanoparticles to PC cream did not induce PC targeting. Therefore, the targeting effect is closely related to the PC-nanoparticles and not a result of either the specific lipid or PC adsorbance to the surface of the formerly drug free nanoparticles. Lipid nanoparticle-induced epidermal targeting may increase the benefit/risk ratio of topical therapy. PMID:12575739

Santos Maia, C; Mehnert, W; Schaller, M; Korting, H C; Gysler, A; Haberland, A; Schäfer-Korting, M

2002-09-01

173

In-situ observation of silver nanoparticle ink at high temperature.  

PubMed

In-situ TEM (transmission electron microscopy) of silver nanoparticle ink at high temperature was carried out. Into a carbon film tube coating the spiral tungsten filament which was attached to the TEM specimen holder, a silver nanoparticle ink was injected. After evaporation, silver nanoparticles with an aggregated structure could be observed. The temperature of the tungsten wire can be controlled by DC current supplied by dry batteries. Fusion of smaller nanoparticles was observed at a higher temperature and some particles were incorporated to larger particles. This technique can be generally used to consider the sintering temperature of such metal nanoparticles. PMID:19458443

Yonezawa, Tetsu

2009-01-01

174

Polymer nanoparticles and nanoparticle arrays  

NASA Astrophysics Data System (ADS)

The manufacturing of polymeric nanoparticles by intramolecular crosslinking is studied by molecular dynamics simulation. Firstly an overview of the intramolecular crosslinking process is obtained by the simulations of benzocyclobutene(BCB)/styrene copolymers using an atomistic model. Then various coarse grained models, including Freely Jointed Chain (FJC). Freely Rotating Chain (FRC) and stiff chain models, are adopted for studying general properties of intramolecular crosslinking of polymers. A temperature series simulation on the FJC model reveals that the change of ambient temperature results in the formation of nanoparticles with distinct morphologies. To describe their structures, a quantity referred to as chemical distance density is introduced, with a quantitative relation between it and the radius of gyration being found. The subsequent study of rigidity effects adopts FRC and stiff chain models. It is found that in the rigid regime, the crosslinking process leaves a substantial number of crosslinkers unlinked, and forms nanoparticles that are significantly larger than their non-rigid counterparts. The Maxwell constraint counting method is used to determine the rigidity thresholds, which yields good agreements with the simulation data. In the last chapter, the atomistic model for polystyrene in the previous crosslinking simulations is employed for a study of polystyrene chains on attractive substrates. The phase diagram and a rough overview of chain dynamics on substrates are obtained.

Liu, Jiwu

175

Engineered virus-like nanoparticle heparin antagonists.  

PubMed

Virus nanoparticles provide a self-assembling, reproducible multivalent platform that can be chemically and genetically manipulated for the presentation of a wide array of epitopes. Presented herein are engineered bacteriophage Q? nanoparticles that function as potent heparin antagonists. Three successful approaches have been used: 1) chemically appending poly-Arg peptides; 2) point mutations to Arg on the virus capsid; 3) incorporation of heparin-binding peptides displayed externally on the virus surface. Each approach generates particles with good heparin antagonist activity with none of the toxic side effects of protamine, the only drug currently FDA-approved for clinical use as a heparin antagonist. PMID:24110638

Udit, Andrew K

2013-07-01

176

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

PubMed

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

Woranuch, Sarekha; Yoksan, Rangrong

2012-10-11

177

Investigation of antibacterial activity of cotton fabric incorporating nano silver colloid  

Microsoft Academic Search

In this work, silver nanoparticles were prepared by polyol process with microwave heating and incorporated on cotton fabric surfaces. The antibacterial performance of the antibacterial cotton fabric was tested for different concentration of nano-sized silver colloid, contact time germs, and washing times. It was found that antibacterial activity increased with the increasing concentration of nano-sized silver colloid. The antibacterial fabric

Ngo Vo Ke Thanh; Nguyen Thi Phuong Phong

2009-01-01

178

Incorporation of Novel Nanostructured Materials into Solar Cells and Nanoelectronic Devices  

Microsoft Academic Search

Each of the investigators on this project has had significant accomplishments toward the production of semiconductor nanoparticles, particles, and thin films and attempts to incorporate these materials into photovoltaics or sensors; to use them for improving fluorescence diagnostics; or to employ them as cancer fighting agents. The synthesis and characterization of the nanomaterials, and more recently the device construction and

Rene Rodriguez; Joshua Pak; Andrew Holland; Alan Hunt; Thomas Bitterwolf; You Qiang; Leah Bergman; Christine Berven; Alex Punnoose; Dmitri Tenne

2011-01-01

179

Synthesis of Ibuprofen Loaded Magnetic Solid Lipid Nanoparticles  

Microsoft Academic Search

Ibuprofen loaded magnetic solid lipid nanoparticles (Ib-MSLNs) were successfully fabricated using a two-step method: 1)preparation of a warm O\\/W microemulsion (aqueous surfactant solution with a lipid phase, containing Ibuprofen, stearic acid, 1-octadecanol and lecithin) in which modified lipophilic magnetite (Fe3O4) nanoparticles were incorporated, and 2)formation of MSLNs by dispersing the warm microemulsion in cold water under mechanical stirring. The Ib-MSLNs

X. J. Pang; J. Zhou; J. J. Chen; M. H. Yu; F. D. Cui; W. L. Zhou

2007-01-01

180

UV and Near-IR triggered release from polymeric nanoparticles  

PubMed Central

A new light-sensitive polymer containing multiple light-sensitive triggering groups along the backbone and incorporating a quinone-methide self-immolative moiety was developed and formulated into nanoparticles encapsulating a model dye Nile Red. Triggered burst-release of the payload upon irradiation and subsequent degradation of the nanoparticles was observed. This system is designed to be versatile where the triggering group can be sensitive to a number of wavelengths.

Fomina, Nadezda; McFearin, Cathryn; Sermsakdi, Marleen; Edigin, Osayimwense; Almutairi, Adah

2010-01-01

181

Nanoparticle technology: Addressing the fundamental roadblocks to protein biomarker discovery  

PubMed Central

The incorporation of affinity baits into N-isopropylacrylamide-hydrogel-based nanoparticles offers a novel technology that addresses the major analytical challenges of disease biomarker discovery. In solution in complex biologic fluids (e.g. blood or urine), core-shell bait-containing nanoparticles can perform three functions in one step: (a) sieve molecules according to size, (b) sequestrate and concentrate target analytes, and (c) protect analytes from degradation.

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

2010-01-01

182

Effect of Inorganic Silver Nanoparticles on Structural and Electrical Properties of Polyaniline\\/PVC Blends  

Microsoft Academic Search

Dodecylbenzenesulfonic acid (DBSA) doped polyaniline (PANDR) has been synthesized by redoping method. Inorganic silver nanoparticles\\u000a were incorporated in THF solution of PANDR (PANDS) and then mixed with PVC solution to prepare PANDS\\/PVC nanocomposites. FTIR\\u000a spectroscopy indicated that silver nanoparticles reside more close to imine nitrogen of PANDS. Transmission electron microscopy\\u000a (TEM) confirmed the formation and dispersion of silver nanoparticles in

Asma B. Afzal; M. Javed Akhtar

2010-01-01

183

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

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

184

Crystallization and Thermal Conductivity of CaCO3 Nanoparticle Filled Polypropylene  

Microsoft Academic Search

Isotactic polypropylene (PP) and calcium carbonate (CaCO3) nanocomposites were prepared by melt extrusion in a twin screw extruder. The effect of CaCO3 nanoparticles on the crystallization and thermal conductivity (TC) of PP was studied by thermal analysis (DSC) and thermal conductivity analysis (TCA). The introduction of CaCO3 nanoparticles resulted in an increase in crystallinity. The incorporation of this nanoparticle (up

M. H. VAKILI; H. EBADI-DEHAGHANI; M. HAGHSHENAS-FARD

2011-01-01

185

Downregulation of Plk1 Expression By Receptor Mediated Uptake of Antisense Oligonucleotide Loaded Nanoparticles1  

Microsoft Academic Search

Human serum albumin (HSA) nanoparticles represent a promising tool for targeted drug delivery to tumor cells. The coupling of the antibody trastuzumab to nanoparticles uses the capability of human epidermal growth factor receptor 2 (HER2)-positive cells to incorporate agents linked to HER2. In our present study, we developed targeted nanoparticles loaded with antisense oligonucleotides (ASOs) against polo-like kinase 1 (Plk1).

Birgit Spänkuch; Isabel Steinhauser; Heidrun Wartlick; Elisabeth Kurunci-Csacsko; Klaus I. Strebhardt; Klaus Langer

186

Magnetic and fluorescent multifunctional chitosan nanoparticles as a smart drug delivery system  

Microsoft Academic Search

An innovative drug delivery system based on magnetic and fluorescent multifunctional chitosan nanoparticles was developed, which combined magnetic targeting, fluorescent imaging and stimulus-responsive drug release properties into one drug delivery system. Water-soluble superparamagnetic Fe3O4 nanoparticles, CdTe quantum dots (QDs) and pharmaceutical drugs were simultaneously incorporated into chitosan nanoparticles; cross-linking the composite particles with glutaraldehyde tailored their size, morphology, surface properties

Linlin Li; Dong Chen; Yanqi Zhang; Zhengtao Deng; Xiangling Ren; Xianwei Meng; Fangqiong Tang; Jun Ren; Lin Zhang

2007-01-01

187

Molecular imaging and therapy of cancer with radiolabeled nanoparticles  

PubMed Central

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

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

2009-01-01

188

Analysis of Adhesion and Fracture Energy of NanoParticle Silver in Electronics Packaging Applications  

Microsoft Academic Search

Nano-particle silver (NPS) conductors are increasingly being investigated for package level electronics applications. Unlike traditional thick film materials and conductive inks, nano-particle conductors often do not incorporate compounds to promote interfacial adhesion such as binders used in thick films and polymer adhesives used in conductive inks as these adhesion promoters can degrade the electrical performance. The NPS is concerned with

Sung Chul Joo; Daniel F. Baldwin

2010-01-01

189

Dual agents loaded PLGA nanoparticles: Systematic study of particle size and drug entrapment efficiency  

Microsoft Academic Search

PLGA nanoparticles simultaneously loaded with vincristine sulfate (VCR) and quercetin (QC) were prepared via O\\/W emulsion solvent evaporation. Six independent processing parameters and PLGA characteristics were assessed systematically to enhance the incorporation of the dual agents with different properties (VCR and QC, hydrophilic and hydrophobic molecule, respectively) into PLGA nanoparticles and control particle size. Approaches investigated for the enhancement of

Xiangrong Song; Yu Zhao; Shixiang Hou; Fangyuan Xu; Rongli Zhao; Junyao He; Zheng Cai; Yuanbo Li; Qiuhong Chen

2008-01-01

190

Computational Studies on the Energy Landscape of Pt-Pd nanoparticles  

Microsoft Academic Search

Bimetallic nanoparticles such as Pt-Pd are currently the subject of intense research mainly due to their important catalytic properties. Clusters structure, composition and degree of mixing or segregation all play important roles in determining their chemical activity. It is presented here an exhaustive study of the structure of Pt-Pd nanoparticles, obtained by a Genetic Algorithm (GA) which incorporates the Gupta

Alvaro Posada-Amarillas; Rafael Pacheco-Contreras; Dora J. Borbón-González; Lauro Oliver Paz-Borbón; Roy L. Johnston; J. Christian Schön

2011-01-01

191

Solid lipid nanoparticles (SLN) for controlled drug delivery – a review of the state of the art  

Microsoft Academic Search

Solid lipid nanoparticles (SLN) introduced in 1991 represent an alternative carrier system to traditional colloidal carriers, such as emulsions, liposomes and polymeric micro- and nanoparticles. SLN combine advantages of the traditional systems but avoid some of their major disadvantages. This paper reviews the present state of the art regarding production techniques for SLN, drug incorporation, loading capacity and drug release,

Rainer H. Müller; Karsten Mäder; Sven Gohla

2000-01-01

192

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

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

193

Polymer chain dynamics and glass transition in athermal polymer\\/nanoparticle mixtures  

Microsoft Academic Search

Polymer nanocomposites (PNCs), prepared by incorporating nanoparticles within a polymer host, generally exhibit properties that differ significantly from those of the host, even with small amounts of nanoparticles. A significant challenge is how to tailor the properties of these materials for applications (structural and biomedical to optoelectronic), because PNCs derive their properties from a collective and complex range of entropic

Hyunjoon Oh; Peter F. Green

2009-01-01

194

Electrospinning method for the preparation of silver chloride nanoparticles in PVP nanofiber  

Microsoft Academic Search

It has been successfully developed by the electrospinning technology that AgCl nanoparticles were incorporated into polymer fiber. In this paper, we chose poly(vinyl pyrrolidone) (PVP) because it was not only a good material for electrospinning but also it was excellent capping reagent of various metal nanoparticles. The silver ions interacted with the carbonyl groups in the PVP molecules. The formation

Jie Bai; Yaoxian Li; Meiye Li; Shugang Wang; Chaoqun Zhang; Qingbiao Yang

2008-01-01

195

Stabilisation effects of superparamagnetic nanoparticles on clustering in nanocomposite microparticles and on magnetic behaviour  

NASA Astrophysics Data System (ADS)

Superparamagnetic nanoparticles of magnetite were coprecipitated from iron salts, dispersed with nitric acid and stabilised either by lactic acid (LA) or by a polycarboxylate-ether polymer (MELPERS4343, MP). The differently stabilised nanoparticles were incorporated into a silica matrix to form nanocomposite microparticles. The silica matrix was prepared either from tetraethylorthosilicate (TEOS) or from an aqueous sodium silicate (water glass) solution. Stabilisation of nanoparticles had a crucial influence on microparticle texture and nanoparticle distribution in the silica matrix.Magnetic measurements in combination with transmission electron microscopy (TEM) investigations suggest a uniform magnetic interaction of nanoparticles in case of LA stabilisation and magnetically interacting nanoparticle clusters of different sizes in case of MP stabilisation. Splitting of blocking temperature (TB) and irreversible temperature (Tir) in zero field cooled (ZFC) and field cooled (FC) measurements is discussed in terms of nanoparticle clustering.

Mandel, K.; Hutter, F.; Gellermann, C.; Sextl, G.

2013-04-01

196

Iron Nanoparticles in Reactive Environmental Barriers  

SciTech Connect

Zero-valent iron is cheap, environmentally innocuous, and effective at reducing chlorinated organics. It has, as a result, become a popular candidate for remediating aquifers contaminated with trichloroethylene and other halogenated pollutants. In this paper, we discuss one such system, where iron nanoparticles are synthesized and incorporated into polyvinyl alcohol membranes, forming water-permeable barriers to these pollutants. These barriers are tested against a variety of contaminants, including carbon tetrachloride, copper, and chromate.

Nuxoll, Eric E.; Shimotori, Tsutomu; Arnold, William A.; Cussler, Edward L.

2003-09-23

197

Electrostatic assembly of binary nanoparticle superlattices using protein cages.  

PubMed

Binary nanoparticle superlattices are periodic nanostructures with lattice constants much shorter than the wavelength of light and could be used to prepare multifunctional metamaterials. Such superlattices are typically made from synthetic nanoparticles, and although biohybrid structures have been developed, incorporating biological building blocks into binary nanoparticle superlattices remains challenging. Protein-based nanocages provide a complex yet monodisperse and geometrically well-defined hollow cage that can be used to encapsulate different materials. Such protein cages have been used to program the self-assembly of encapsulated materials to form free-standing crystals and superlattices at interfaces or in solution. Here, we show that electrostatically patchy protein cages--cowpea chlorotic mottle virus and ferritin cages--can be used to direct the self-assembly of three-dimensional binary superlattices. The negatively charged cages can encapsulate RNA or superparamagnetic iron oxide nanoparticles, and the superlattices are formed through tunable electrostatic interactions with positively charged gold nanoparticles. Gold nanoparticles and viruses form an AB(8)(fcc) crystal structure that is not isostructural with any known atomic or molecular crystal structure and has previously been observed only with large colloidal polymer particles. Gold nanoparticles and empty or nanoparticle-loaded ferritin cages form an interpenetrating simple cubic AB structure (isostructural with CsCl). We also show that these magnetic assemblies provide contrast enhancement in magnetic resonance imaging. PMID:23241655

Kostiainen, Mauri A; Hiekkataipale, Panu; Laiho, Ari; Lemieux, Vincent; Seitsonen, Jani; Ruokolainen, Janne; Ceci, Pierpaolo

2012-12-16

198

Synthesis and Characterization of Gold-Titanium Dioxide Nanoparticles  

NASA Astrophysics Data System (ADS)

Nanoparticles are of recent scientific interest due to their unique size-dependent optical, electrical, and catalytic properties. Gold nanoparticles specifically, have many potential applications, especially in optoelectronic devices due to their optical properties and plasmon resonance. The specific goals of this research are to synthesize Au/TiO2 core-shell nanoparticles for their use in improving the overall efficiency of P3HT/PCBM polymer solar cells previously prepared in our lab. The standard sodium citrate reduction method was used to synthesize gold nanoparticles with an average diameter of 15 nm. Through changing the concentration of sodium citrate in solution we were able to tune the size of the nanoparticles, and therefore change their light-absorbing properties. The goals of this research are to cap the gold nanoparticles with TiO2 through a sol-gel method. Characterization of the Au/TiO2 particles will be performed using high resolution tunneling electron microscopy to determine the size of the nanoparticles and the thickness of the TiO2 shell. In addition, ultraviolet-visual spectroscopy was used to determine the absorption of the particles, and dynamic light scattering was used to confirm the size distribution of the particles. The incorporation of Au/TiO2 nanoparticles in P3HT/PCBM devices will be discussed.

Cramer, Hailey; Shah, Ismat

2013-03-01

199

Electrostatic assembly of binary nanoparticle superlattices using protein cages  

NASA Astrophysics Data System (ADS)

Binary nanoparticle superlattices are periodic nanostructures with lattice constants much shorter than the wavelength of light and could be used to prepare multifunctional metamaterials. Such superlattices are typically made from synthetic nanoparticles, and although biohybrid structures have been developed, incorporating biological building blocks into binary nanoparticle superlattices remains challenging. Protein-based nanocages provide a complex yet monodisperse and geometrically well-defined hollow cage that can be used to encapsulate different materials. Such protein cages have been used to program the self-assembly of encapsulated materials to form free-standing crystals and superlattices at interfaces or in solution. Here, we show that electrostatically patchy protein cages--cowpea chlorotic mottle virus and ferritin cages--can be used to direct the self-assembly of three-dimensional binary superlattices. The negatively charged cages can encapsulate RNA or superparamagnetic iron oxide nanoparticles, and the superlattices are formed through tunable electrostatic interactions with positively charged gold nanoparticles. Gold nanoparticles and viruses form an AB8fcc crystal structure that is not isostructural with any known atomic or molecular crystal structure and has previously been observed only with large colloidal polymer particles. Gold nanoparticles and empty or nanoparticle-loaded ferritin cages form an interpenetrating simple cubic AB structure (isostructural with CsCl). We also show that these magnetic assemblies provide contrast enhancement in magnetic resonance imaging.

Kostiainen, Mauri A.; Hiekkataipale, Panu; Laiho, Ari; Lemieux, Vincent; Seitsonen, Jani; Ruokolainen, Janne; Ceci, Pierpaolo

2013-01-01

200

Nanoparticles by Laser Ablation  

Microsoft Academic Search

This review concerns nanoparticles collected in the form of nanopowder or a colloidal solution by laser ablating a solid target that lies in a gaseous or a liquid environment. The paper discusses the advantages of the method as compared with other methods for nanoparticle synthesis, outlines the factors on which the properties of the produced nanoparticles depend, explains the mechanisms

N. G. Semaltianos

2010-01-01

201

Incorporating externalities in conservation programs  

SciTech Connect

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.

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

1995-06-01

202

On the thermal stability of volume holograms recorded in nanoparticle-polymer composite films  

NASA Astrophysics Data System (ADS)

We report on measurements of thermal expansion coefficients and temperature-dependent refractive indices of nanoparticle-polymer composite films in which plane-wave volume holograms are recorded. These physical constants are evaluated for photopolymer films with the incorporation of inorganic nanoparticles or binder polymer. We show that the incorporation of inorganic nanoparticles in photopolymer is a very effective method to suppress temperature-dependent film-thickness and refractive-index changes as well as to increase the refractive index modulation and reduce polymerization shrinkage.

Tomita, Yasuo; Nakamura, Toshihiro; Tago, Atsushi

2008-05-01

203

Finite Size Effects on the Real-Space Pair Distribution Function of Nanoparticles  

SciTech Connect

The pair distribution function (PDF) method is a powerful approach for the analysis of the structure of nanoparticles. An important approximation used in nanoparticle PDF simulations is the incorporation of a form factor describing nanoparticle size and shape. The precise effect of the form factor on the PDF is determined by both particle shape and structure if these characteristics are both anisotropic and correlated. The correct incorporation of finite size effects is important for distinguishing and quantifying the structural consequences of small particle size in nanomaterials.

Gilbert, Benjamin

2008-10-01

204

Investigation of antibacterial activity of cotton fabric incorporating nano silver colloid  

NASA Astrophysics Data System (ADS)

In this work, silver nanoparticles were prepared by polyol process with microwave heating and incorporated on cotton fabric surfaces. The antibacterial performance of the antibacterial cotton fabric was tested for different concentration of nano-sized silver colloid, contact time germs, and washing times. It was found that antibacterial activity increased with the increasing concentration of nano-sized silver colloid. The antibacterial fabric with 758 mg/kg of silver nanoparticles on surface cotton was highly effective in killing test bacteria and had excellent water resisting property.

Thanh, Ngo Vo Ke; Thi Phuong Phong, Nguyen

2009-09-01

205

Synthesis, characterization and UV-shielding property of polystyrene-embedded CeO2 nanoparticles  

NASA Astrophysics Data System (ADS)

A cerium-triethanolamine (TEA) complex was prepared and used as the precursor to synthesize CeO2 nanoparticles. It was mixed with styrene (St) in aqueous solution and hydrolysized to generate CeO2 nanoparticles. In situ emulsion polymerization of the monomer was followed in one pot. The CeO2 nanoparticles were incorporated into polystyrene (PS) matrix and dispersed homogeneously, with an average crystallite size of 3-5 nm and a band gap at 3.01 eV. Meanwhile, the embedding of the CeO2 nanoparticles can enhance UV-shielding property of PS.

Liu, Kang-Qiang; Kuang, Cheng-Xiu; Zhong, Ming-Qiang; Shi, Yan-Qin; Chen, Feng

2013-10-01

206

Multipositional silica-coated silver nanoparticles for high-performance polymer solar cells.  

PubMed

We demonstrate high-performance polymer solar cells using the plasmonic effect of multipositional silica-coated silver nanoparticles. The location of the nanoparticles is critical for increasing light absorption and scattering via enhanced electric field distribution. The device incorporating nanoparticles between the hole transport layer and the active layer achieves a power conversion efficiency of 8.92% with an external quantum efficiency of 81.5%. These device efficiencies are the highest values reported to date for plasmonic polymer solar cells using metal nanoparticles. PMID:23611150

Choi, Hyosung; Lee, Jung-Pil; Ko, Seo-Jin; Jung, Jae-Woo; Park, Hyungmin; Yoo, Seungmin; Park, Okji; Jeong, Jong-Ryul; Park, Soojin; Kim, Jin Young

2013-04-23

207

Cell tracking using nanoparticles.  

PubMed

Tracking cells in regenerative medicine is becoming increasingly important for basic cell therapy science, for cell delivery optimization and for accurate biodistribution studies. This report describes nanoparticles that utilize stable-isotope metal labels for multiple detection technologies in preclinical studies. Cells labeled with nanoparticles can be imaged by electron microscopy, fluorescence, and magnetic resonance. The nanoparticle-labeled cells can be quantified by neutron activation, thereby allowing, with the use of standard curves, the determination of the number of labeled cells in tissue samples from in vivo sources. This report describes the characteristics of these nanoparticles and methods for using these nanoparticles to label and track cells. PMID:20559922

Vaccaro, Dennis E; Yang, Meiheng; Weinberg, James S; Reinhardt, Christopher P; Groman, Ernest V

2008-07-08

208

Assessing nanoparticle toxicity.  

PubMed

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. PMID:22524221

Love, Sara A; Maurer-Jones, Melissa A; Thompson, John W; Lin, Yu-Shen; Haynes, Christy L

2012-04-09

209

Fluoride Incorporation and Apatite Solubility  

Microsoft Academic Search

The classical theory on the solubility of ionic compounds has been extended to solid solutions and deviations from stoichiometry by combination of thermodynamical and solid state chemical principles. Theory predicts that the incorporation of foreign ions in enamel apatite can change its solubility product over several orders of magnitude in several ways. Experimental data on the composition of enamel indicate

F. C. M. Driessens

1973-01-01

210

Incorporating Yoga Into College Counseling  

Microsoft Academic Search

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

Christopher M. Adams; Ana Puig

2008-01-01

211

[Teratogenic effects of incorporated radionuclides].  

PubMed

Experimental data on teratogenic effects induced by incorporated alpha, beta and gamma-emitters were analyzed. It was found that the radioactive substances as well as external irradiation induced teratogenic effects. Teratogenesis caused by incorporated radionuclides has some peculiarities compared to the effect caused by fetus exposure to external radiation. These peculiarities are related to the fact of the limited penetration of incorporated radionuclides via placenta barrier so the radiation fetal doses are accumulated within long period of time and radiation dose rates are relatively low. The exposure to incorporated radionuclides does not induce severe developmental defects. Most frequent developmental defects of fetus include its death, general retardation of the development and growth. In such case the earlier pregnancy term was affected by radionuclide the more severe fetal damages occur in fetus because of the gradual increase of absorbed dose even in case of single intake of radionuclide. RBEs of radionuclides if compared to that for external gamma radiation are evaluated as follows: 2-4 (tritium oxide), 20 (241Am), 50 (238Pu) and 3-5 (131I in thyroid). PMID:11898639

Liaginskaia, A M; Osipov, V A

212

In Vivo Sustained Release of siRNA from Solid Lipid Nanoparticles  

PubMed Central

Small interfering RNA (siRNA) is a highly potent drug in gene-based therapy with a challenge of being delivered in a sustained manner. Nanoparticle drug delivery systems allow for incorporating and controlled release of therapeutic payloads. We demonstrate that solid lipid nanoparticles can incorporate and provide sustained release of siRNA. Tristearin solid lipid nanoparticles, made by nanoprecipitation, were loaded with siRNA (4.4–5.5 weight percent loading ratio) using a hydrophobic ion pairing approach that employs the cationic lipid DOTAP. Intradermal injection of these nanocarriers in mouse footpads resulted in prolonged siRNA release over a period of 10–13 days. In vitro cell studies showed that the released siRNA retained its activity. Nanoparticles developed in this study offer an alternative approach to polymeric nanoparticles for encapsulation and sustained delivery of siRNA with the advantage of being prepared from physiologically well-tolerated materials.

Lobovkina, Tatsiana; Jacobson, Gunilla B.; Gonzalez, Emilio Gonzalez; Hickerson, Robyn P.; Leake, Devin; Kaspar, Roger L.; Contag, Christopher H.; Zare, Richard N.

2011-01-01

213

Dynamics of Nanoparticle Adhesion  

NASA Astrophysics Data System (ADS)

We have performed molecular dynamics simulations of peeling of nanoparticles from substrate to understand the dynamics of nanoparticle adhesion. In our simulations we have calculated the potential of mean force characterizing the strength of the nanoparticle interaction with the substrate as a function of the particle-substrate separation. These simulations have shown that the detachment of the nanoparticle from substrate occurs through neck formation. The neck height decreases with increasing nanoparticle shear modulus (crosslinking density). Furthermore our simulations have established that the detachment time tR scales with the applied force as f-5. This strong force dependence is a result of the fine interplay between nanoparticle surface energy, elastic energy and its adhesion to the substrate that controls the shape of the nanoparticle.

Dobrynin, Andrey; Carrillo, Jan-Michael; Raphael, Elie

2012-02-01

214

Fabrication and characterization of II-VI semiconductor nanoparticles decorated electrospun polyacrylonitrile nanofibers.  

PubMed

Semiconductor nanoparticles incorporated highly aligned electrospun polyacrylonitrile (PAN) composite nanofibers were obtained via a simple, scalable and low-cost dip coating technique at room temperature. The resultant PAN nanofibers exhibited good incorporation of CdS, ZnS and CoS semiconductor nanoparticles. The detailed characterizations of these composite nanofibers were investigated. The incorporation of semiconductor nanoparticles on the surfaces of PAN nanofibers were confirmed by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction analysis. The current-voltage (I-V) characteristics revealed that the electrical conductivity of these composite nanofibers were higher than that of the pristine PAN nanofibers. Overall, the feasibility of obtaining uniformly dispersed semiconductor nanoparticles on PAN nanofibers can be utilized for the realization of various nanotechnological device applications. PMID:23453708

Nirmala, R; Jeon, Kyungsoo; Navamathavan, R; Kim, Byoung-Suhk; Khil, Myung-Seob; Kim, Hak Yong

2013-02-08

215

Solid Lipid Nanoparticles: A Modern Formulation Approach in Drug Delivery System  

PubMed Central

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.

Mukherjee, S.; Ray, S.; Thakur, R. S.

2009-01-01

216

Silver Nanoparticles in Cellulose Acetate Polymers: Rheological and Morphological Properties  

Microsoft Academic Search

Silver nitrate was incorporated in cellulose acetate with different substitution degrees as a dispersion medium. Silver-containing polymer solutions in 2-methoxyethanol were rheologically investigated, both before and after boiling, which permitted a better understanding of the morphological aspects of the corresponding cast films. The different distribution of the obtained silver nanoparticles in the polymer matrix, as well as the influence of

Adina Maria Necula; Iuliana Stoica; Niculae Olaru; Florica Doroftei; Silvia Ioan

2011-01-01

217

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

PubMed

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

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

2013-08-27

218

A simple method to ordered mesoporous carbons containing nickel nanoparticles  

SciTech Connect

A series of ordered mesoporous carbons containing magnetic Ni nanoparticles (Ni-OMCs) with a variety of Ni loadings was made by a simple one-pot synthetic procedure through carbonization of phenolic resin-Pluronic block copolymer composites containing various amount of nickel nitrate. Such composite materials were characterized by N{sub 2} sorption, XRD, and STEM. Ni-OMCs exhibited high BET surface area, uniform pore size, and large pore volume without obvious pore blockage with a Ni loading as high as 15 wt%. Ni nanoparticles were crystalline with a face-center-cubic phase and observed mainly in the carbon matrix and on the outer surface as well. The average particle size of Ni nanoparticles was dependent on the preparation (carbonization) temperature and Ni loading; the higher the temperature was used and the more the Ni was incorporated, the larger the Ni nanoparticles were observed. One of the applications of Ni-OMCs was demonstrated as magnetically separable adsorbents.

Dai, Sheng [ORNL; Wang, Xiqing [ORNL

2009-01-01

219

Synthesis and biomedical applications of functionalized fluorescent and magnetic dual reporter nanoparticles as obtained in the miniemulsion process  

Microsoft Academic Search

As superparamagnetic nanoparticles capture new applications and markets, the flexibility and modifications of these nanoparticles are increasingly important aspects. Therefore a series of magnetic polystyrene particles encapsulating magnetite nanoparticles (10-12 nm) in a hydrophobic poly(styrene-co-acrylic acid) shell was synthesized by a three-step miniemulsion process. A high amount of iron oxide was incorporated by this process (typically 30-40% (w\\/w)). As a

Verena Holzapfel; Myriam Lorenz; Clemens Kilian Weiss; Hubert Schrezenmeier; Katharina Landfester; Volker Mailänder

2006-01-01

220

Engineering of lipid-coated PLGA nanoparticles with a tunable payload of diagnostically active nanocrystals for medical imaging†  

PubMed Central

Polylactic-co-glycolic acid (PLGA) based nanoparticles are biocompatible and biodegradable and therefore have been extensively investigated as therapeutic carriers. Here, we engineered diagnostically active PLGA nanoparticles that incorporate high payloads of nanocrystals into their core for tunable bioimaging features. We accomplished this through esterification reactions of PLGA to generate polymers modified with nanocrystals. The PLGA nanoparticles formed from modified PLGA polymers that were functionalized with either gold nanocrystals or quantum dots exhibited favorable features for computed tomography and optical imaging, respectively.

Mieszawska, Aneta J.; Gianella, Anita; Cormode, David P.; Zhao, Yiming; Meijerink, Andries; Langer, Robert; Farokhzad, Omid C.; Fayad, Zahi A.; Mulder, Willem J. M.

2013-01-01

221

Contact Mechanics of Nanoparticles  

NASA Astrophysics Data System (ADS)

We perform molecular dynamics simulations of the detachment of nanoparticles from a substrate. The critical detachment force, f*, is obtained as a function of the nanoparticle radius, Rp, shear modulus, G, surface energy, ?p, and work of adhesion, W. The magnitude of the detachment force is shown to increase from ?WRp to 2.2?WRp with increasing nanoparticle shear modulus and nanoparticle size. This variation of the detachment force is a manifestation of a neck formation upon nanoparticle detachment. Using scaling analysis, we show that the magnitude of the detachment force is controlled by the balance of the nanoparticle elastic energy, surface energy of the neck, and nanoparticle adhesion energy to a substrate. It is a function of the dimensionless parameter ??p(GRp)-1/3W-2/3which is proportional to the ratio of the surface energy of a neck and the elastic energy of deformed nanoparticle. In the case of small values of the parameter ? 1, the critical detachment force approaches a critical Johnson, Kendall and Roberts force, f* 1.5?WRp, as is usually the case for strongly crosslinked large nanoparticles. However, in the opposite limit, corresponding to soft small nanoparticles, for which ?1, the critical detachment force, f*, scales as f*?p^3/2 Rp^1/2 G-1/2. Simulation data are described by a scaling function f*?p^3/2 Rp^1/2 G-1/2&-1.89circ; .

Carrillo, J.-M. Y.; Dobrynin, A. V.

2013-03-01

222

A nanoparticle in plasma  

SciTech Connect

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.

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

2009-06-15

223

Thermal characterization of nano ZnO incorporated natural rubber latex  

NASA Astrophysics Data System (ADS)

A laser induced photoacoustic technique has been employed to measure the thermal effusivity value of natural rubber latex in the liquid as well as in the solid state. The nano Zinc Oxide particles synthesized via precipitation technique is incorporated to the natural rubber latex. The influence of molar fractions of nanoparticles on the thermal effusivity value of host polymer is investigated. Detailed analysis of the results shows that the rubber latex in the solid state exhibits lower value for the thermal effusivity value in comparison to the liquid state. The molar fraction of the nanoparticle is found to influence the effective thermal effusivity value in a substantial manner. Results are explained in terms of nanoparticle and phonon assisted thermal energy transport in these samples.

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

2010-08-01

224

Functionalized Fe?O?@Au superparamagnetic nanoparticles: in vitro bioactivity.  

PubMed

The interaction of nanoparticles with cells has been a focus of interest during the past decade. We report the fabrication and characterization of hydrosoluble Fe?O?@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 Fe?O?@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. PMID:22802157

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

2012-08-10

225

Multifunctional gold nanoparticles for diagnosis and therapy of disease.  

PubMed

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 nontoxic. 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 aforementioned 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. This 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

Mieszawska, Aneta J; Mulder, Willem J M; Fayad, Zahi A; Cormode, David P

2013-02-11

226

Nanoparticle-modified monolithic pipette tips for phosphopeptide enrichment.  

PubMed

We have developed nanoparticle-modified monoliths in pipette tips for selective and efficient enrichment of phosphopeptides. The 5 ?L monolithic beds were prepared by UV-initiated polymerization in 200 ?L polypropylene pipette tips and either iron oxide or hydroxyapatite nanoparticles were used for monolith modification. Iron oxide nanoparticles were prepared by a co-precipitation method and stabilized by citrate ions. A stable coating of iron oxide nanoparticles on the pore surface of the monolith was obtained via multivalent electrostatic interactions of citrate ions on the surface of nanoparticles with a quaternary amine functionalized poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) monolith. Hydroxyapatite nanoparticles were incorporated into the poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) monolith by simply admixing them in the polymerization mixture followed by in situ polymerization. The nanoparticle-modified monoliths were compared with commercially available titanium dioxide pipette tips. Performance of the developed and commercially available sorbents was demonstrated with the efficient and selective enrichment of phosphopeptides from peptide mixtures of ?-casein and ?-casein digests followed by off-line MALDI/MS analysis. PMID:22926133

Krenkova, Jana; Foret, Frantisek

2012-08-29

227

A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles  

PubMed Central

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.

2011-01-01

228

A comparative study of non-covalent encapsulation methods for organic dyes into silica nanoparticles  

NASA Astrophysics Data System (ADS)

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.

Auger, Aurélien; Samuel, Jorice; Poncelet, Olivier; Raccurt, Olivier

2011-12-01

229

Environmental Feedbacks and Engineered Nanoparticles: Mitigation of Silver Nanoparticle Toxicity to Chlamydomonas reinhardtii by Algal-Produced Organic Compounds.  

PubMed

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

Stevenson, Louise M; Dickson, Helen; Klanjscek, Tin; Keller, Arturo A; McCauley, Edward; Nisbet, Roger M

2013-09-23

230

Environmental Feedbacks and Engineered Nanoparticles: Mitigation of Silver Nanoparticle Toxicity to Chlamydomonas reinhardtii by Algal-Produced Organic Compounds  

PubMed Central

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.

Stevenson, Louise M.; Dickson, Helen; Klanjscek, Tin; Keller, Arturo A.; McCauley, Edward; Nisbet, Roger M.

2013-01-01

231

Preparation, Characterization and in vitro Toxicity Test of Magnetic Nanoparticle-Based Drug Delivery System to Hyperthermia of Biological Tissues  

Microsoft Academic Search

The goals of this study were first to prepare and second to test albumin-based beads containing maghemite nanoparticles dispersed on them. Incorporation of maghemite nanoparticles in the albumin-based template, allowing full control of the magnetic content, was accomplished by adding ionic magnetic fluid to the albumin suspension, following heat denaturation. The material evaluation was performed using Zeta potential measurements and

Andreza Ribeiro Simioni; Fernando Lucas Primo; Marcilene Machado Andrade Rodrigues; Zulmira Guerrero Marques Lacava; Paulo Cesar Morais; Antonio Claudio Tedesco

2007-01-01

232

Effect of nickel incorporation on the optical properties of diamond-like carbon (DLC) matrix  

NASA Astrophysics Data System (ADS)

The present study investigates the optical behavior of composite nanostructured DLC based films and functional coatings. Diamond-like carbon (DLC) thin films were synthesized by electrodeposition method onto SnO 2 -coated glass substrates using an electrolyte of a mixture of acetic acid and water. Nanoparticles of nickel were then introduced into the DLC matrix. Morphology of the metal incorporated thin films and distribution of nanoparticles were studied by SEM; continuous homogeneous distribution of the particles was observed. Raman spectroscopy showed additional peaks in addition to the peaks due to DLC matrix. FTIR spectra revealed new peaks in the lower wave number region due to metal inclusion. UV-vis transmittance studies were performed to calculate the band gap of the samples. The estimated band gap from the Tauc relation was found to vary from 2.63 eV for the virgin DLC to 1.48 eV for the metal incorporated DLC.

Pandey, B.; Hussain, S.

2011-10-01

233

Radiolabelling of engineered nanoparticles for in vitro and in vivo tracing applications using cyclotron accelerators.  

PubMed

We present in this article an outline of some cyclotron-based irradiation techniques that can be used to directly radiolabel industrially manufactured nanoparticles, as well as two techniques for synthesis of labelled nanoparticles using cyclotron-generated radioactive precursor materials. These radiolabelled nanoparticles are suitable for a range of different in vitro and in vivo tracing studies of relevance to the field of nanotoxicology. A basic overview is given of the relevant physics of nuclear reactions regarding both ion-beam and neutron production of radioisotopes. The various issues that determine the practicality and usefulness of the different methods are discussed, including radioisotope yield, nuclear reaction kinetics, radiation and thermal damage, and radiolabel stability. Experimental details are presented regarding several techniques applied in our laboratories, including direct light-ion activation of dry nanoparticle samples, neutron activation of nanoparticles and suspensions using an ion-beam driven activator, spark-ignition generation of nanoparticle aerosols using activated electrode materials, and radiochemical synthesis of nanoparticles using cyclotron-produced isotopes. The application of these techniques is illustrated through short descriptions of some selected results thus far achieved. It is shown that these cyclotron-based methods offer a very useful range of options for nanoparticle radiolabelling despite some experimental difficulties associated with their application. For direct nanoparticle radiolabelling, if care is taken in choosing the experimental conditions applied, useful activity levels can be achieved in a wide range of nanoparticle types, without causing substantial thermal or radiation damage to the nanoparticle structure. Nanoparticle synthesis using radioactive precursors presents a different set of issues and offers a complementary and equally valid approach when laboratory generation of the nanoparticles is acceptable for the proposed studies, and where an appropriate radiolabel can be incorporated into the nanoparticles during synthesis. PMID:21479952

Gibson, N; Holzwarth, U; Abbas, K; Simonelli, F; Kozempel, J; Cydzik, I; Cotogno, G; Bulgheroni, A; Gilliland, D; Ponti, J; Franchini, F; Marmorato, P; Stamm, H; Kreyling, W; Wenk, A; Semmler-Behnke, M; Buono, S; Maciocco, L; Burgio, N

2011-04-11

234

Adhesion of Nanoparticles  

Microsoft Academic Search

We have developed a new model of nanoparticle adhesion which explicitly takes into account the change in the nanoparticle surface energy. Using combination of the molecular dynamics simulations and theoretical calculations we have showed that the deformation of the adsorbed nanoparticles is a function of the dimensionless parameter betagamma( GR )-2\\/3W-1\\/3, where G is the particle shear modulus, R is

Jan-Michael Carrillo; Elie Raphael; Andrey Dobrynin

2011-01-01

235

Nanoparticles for Pulmonary Delivery  

Microsoft Academic Search

\\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

Alan B. Watts; Robert O. Williams

236

Photosynthesis of nanoparticles  

Microsoft Academic Search

This work is devoted to an overview of the physical processes that underlie a recently developed method for the photosynthesis\\u000a of nanoparticles. The results of nanoparticle synthesis under the condensation of supersaturated atomic vapor produced by\\u000a the photodissociation of carbon- and metal-bearing compounds are demonstrated. The different factors affecting the formation\\u000a kinetics of carbon and metal nanoparticles are analyzed. The

E. V. Gurentsov; A. V. Eremin

2009-01-01

237

Functional Magnetic Nanoparticles  

Microsoft Academic Search

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.\\u000aMagnetite nanoparticles

James Gass

2012-01-01

238

Synthesis and Characterization of Nano-Silver Incorporated Natural Rubber Latex Foam  

Microsoft Academic Search

Synthesis and characterization of silver nanoparticles (SNP) incorporated natural rubber latex foam (NRLF) is described. SNP synthesized by reducing of Silver Nitrate (AgNO3) with Tri-Sodium Citrate (TSC) were adsorbed in-situ on to the NRLF matrix. Antimicrobial activities were tested by qualitatively and quantitatively against Gram positive Staphylococcus aureus and Gram negative Escherichia coli. It was found that the resultant NRLF

Indrajith Rathnayake; Hanafi Ismail; Baharin Azahari; Nalin Dammika Darsanasiri; Sanath Rajapakse

2012-01-01

239

Adhesion of Nanoparticles  

NASA Astrophysics Data System (ADS)

We have developed a new model of nanoparticle adhesion which explicitly takes into account the change in the nanoparticle surface energy. Using combination of the molecular dynamics simulations and theoretical calculations we have showed that the deformation of the adsorbed nanoparticles is a function of the dimensionless parameter ??( GR )-2/3W-1/3, where G is the particle shear modulus, R is the initial particle radius, ? is the polymer interfacial energy, and W is the particle work of adhesion. In the case of small values of the parameter ?<0.1, which is usually the case for strongly cross-linked large nanoparticles, the particle deformation can be described in the framework of the classical Johnson, Kendall, and Roberts (JKR) theory. However, we observed a significant deviation from the classical JKR theory in the case of the weakly cross-linked nanoparticles that experience large shape deformations upon particle adhesion. In this case the interfacial energy of the nanoparticle plays an important role controlling nanoparticle deformation. Our model of the nanoparticle adhesion is in a very good agreement with the simulation results and provides a new universal scaling relationship for nanoparticle deformation as a function of the system parameters.

Carrillo, Jan-Michael; Raphael, Elie; Dobrynin, Andrey

2011-03-01

240

Nanoparticles for biomedical imaging  

PubMed Central

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.

Nune, Satish K; Gunda, Padmaja; Thallapally, Praveen K; Lin, Ying-Ying; Forrest, M Laird; Berkland, Cory J

2011-01-01

241

Holographic characteristics of citrate ion modified gold nano-particles dispersed photopolymer  

NASA Astrophysics Data System (ADS)

Hydrophilic photopolymers with AA as the monomer are versatile materials for use as holographic recording media. It has demonstrated a possibility to improve the refractive index modulation by doping inorganic nanoparticles into the polymer matrix. But the agglomerate effect of inorganic nanoparticles always deteriorate the holographic storage characteristics of the inorganic nanoparticle dispersed photopolymer compound materials. monodisperse hydrophilic gold nanoparticles are fabricated by the method of sodium citrate reduction, and then were dispersed into the PVA/AA photopolymer. Our results indicate that citrate ions coated on the surface of gold nanoparticles can effectively prevent the agglomerate effect, so that the gold nanoparticles can uniformly dispersed in the sol-gel photopolymer. The permanent refractive index grating can be formed owing to a spatial distribution of the effective refractive index with periodically distributed nanoparticles and polymerized monomers during the holographic recording. Furthermore, the citrate ion modified gold nanoparticles and polymer chain can induce the formation of hydrogen bonds which can prevent the material from distortion and at the same time improve the stability of the material by the coordination effect of carboxylate. Therefore, the incorporation of gold nanoparticles leads to a significantly improvement in the holographic properties of the materials, so that the volume shrinkage during the holographic exposure can be well suppressed. Additionally, there exists the optimum concentration of gold nanoparticles, at which the maximum diffraction efficiency can be as high as 90% and the volume shrinkage can be reduced to 0.8%.

Xue, Xiao-yu; Hai, Fu-Sheng; Gao, Li-Zhen; He, Fei; Li, Chun-Liu; Li, Yun-Xi; Huang, Ming-Ju

242

Kaempferol-7-O-beta-D-glucoside (KG) isolated from Smilax china L. rhizome induces G2/M phase arrest and apoptosis on HeLa cells in a p53-independent manner.  

PubMed

Kaempferol-7-O-beta-D-glucoside (KG), a flavonoid glycoside, isolated from Smilax china L. rhizome, displayed marked anticancer activity on a panel of established cancer cells, of which, HeLa human cervix carcinoma cells were the most sensitive. Meanwhile, the cytotoxic effects of KG on normal human cells (HEK293 embryonic kidney cells and L-02 embryonic liver cells) were much smaller than on cancer cells. This work studied the molecular mechanisms underlying KG induced growth inhibition in HeLa cells. The results showed that KG induced G2/M phase growth arrest correlated with Cyclin B1 and Cdk1 decrease in a p53-independent manner, and also caused an increase in apoptosis, which was confirmed by characteristic morphological changes, evident DNA fragmentation, increased apoptotic sub-G1 population. Furthermore, inhibition of NF-kappaB nuclear translocation, up-regulation of Bax and down-regulation of Bcl-2, were observed in HeLa cells treated with KG, which indicated that the mitochondrial pathway was involved in the apoptosis signal pathway. In summary, KG displayed a significant anti-tumor effect through cell cycle arrest and apoptotic induction in HeLa cells, which suggested that KG might have therapeutic potential against cervix carcinoma. PMID:18343026

Xu, Wen; Liu, Jianwen; Li, Changlong; Wu, He-Zhen; Liu, Yan-Wen

2008-03-14

243

Imparting functionality to a metal-organic framework material by controlled nanoparticle encapsulation  

NASA Astrophysics Data System (ADS)

Microporous metal-organic frameworks (MOFs) that display permanent porosity show great promise for a myriad of purposes. The potential applications of MOFs can be developed further and extended by encapsulating various functional species (for example, nanoparticles) within the frameworks. However, despite increasing numbers of reports of nanoparticle/MOF composites, simultaneously to control the size, composition, dispersed nature, spatial distribution and confinement of the incorporated nanoparticles within MOF matrices remains a significant challenge. Here, we report a controlled encapsulation strategy that enables surfactant-capped nanostructured objects of various sizes, shapes and compositions to be enshrouded by a zeolitic imidazolate framework (ZIF-8). The incorporated nanoparticles are well dispersed and fully confined within the ZIF-8 crystals. This strategy also allows the controlled incorporation of multiple nanoparticles within each ZIF-8 crystallite. The as-prepared nanoparticle/ZIF-8 composites exhibit active (catalytic, magnetic and optical) properties that derive from the nanoparticles as well as molecular sieving and orientation effects that originate from the framework material.

Lu, Guang; Li, Shaozhou; Guo, Zhen; Farha, Omar K.; Hauser, Brad G.; Qi, Xiaoying; Wang, Yi; Wang, Xin; Han, Sanyang; Liu, Xiaogang; Duchene, Joseph S.; Zhang, Hua; Zhang, Qichun; Chen, Xiaodong; Ma, Jan; Loo, Say Chye Joachim; Wei, Wei D.; Yang, Yanhui; Hupp, Joseph T.; Huo, Fengwei

2012-04-01

244

Microwave-induced synthesis of highly dispersed gold nanoparticles within the pore channels of mesoporous silica  

SciTech Connect

Highly dispersed gold nanoparticles have been incorporated into the pore channels of SBA-15 mesoporous silica through a newly developed strategy assisted by microwave radiation (MR). The sizes of gold are effectively controlled attributed to the rapid and homogeneous nucleation, simultaneous propagation and termination of gold precursor by MR. Diol moieties with high dielectric and dielectric loss constants, and hence a high microwave activation, were firstly introduced to the pore channels of SBA-15 by a simple addition reaction between amino group and glycidiol and subsequently served as the reduction centers for gold nanoparticles. Extraction of the entrapped gold from the nanocomposite resulted in milligram quantities of gold nanoparticles with low dispersity. The successful assembly process of diol groups and formation of gold nanoparticles were monitored and tracked by solid-state NMR and UV-vis measurements. Characterization by small angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the incorporation of gold nanoparticles would not breakup the structural integrity and long-range periodicity of SBA-15. The gold nanoparticles had a narrow size distribution with diameters in the size range of 5-10 nm through TEM observation. The average particles size is 7.9 nm via calculation by the Scherrer formula and TEM measurements. Nitrogen adsorption and desorption isotherms gave further evidence that the employed method was efficient and gold nanoparticles were successfully incorporated into the pore channels of SBA-15. - Graphical abstract: A facile and novel strategy has been developed to incorporate gold nanoparticles into the pore channels of mesoporous SBA-15 assisted by microwave radiation (MR) with mild reaction condition and rapid reaction speed. Due to the rapid and homogeneous nucleation, simultaneous propagation and termination by MR, the size of gold nanoparticles are effectively controlled.

Gu Jinlou; Fan Wei; Shimojima, Atsushi [Department of Chemical System Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Okubo, Tatsuya [Department of Chemical System Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)], E-mail: okubo@chemsys.t.u-tokyo.ac.jp

2008-04-15

245

Mesoporous carbon incorporated metal oxide nanomaterials as supercapacitor electrodes.  

PubMed

Supercapacitors have attracted huge attention in recent years as they have the potential to satisfy the demand of both huge energy and power density in many advanced technologies. However, poor conductivity and cycling stability remains to be the major challenge for its widespread application. Various strategies have been developed for meeting the ever-increasing energy and power demands in supercapacitors. This Research News article aims to review recent progress in the development of mesoporous carbon incorporated metal oxide nanomaterials, especially metal oxide nanoparticles confined in ordered mesoporous carbon and 1D metal oxides coated with a layer of mesoporous carbon for high-performance supercapacitor applications. In addition, a recent trend in supercapacitor development - hierarchical porous graphitic carbons (HPGC) combining macroporous cores, mesoporous walls, and micropores as an excellent support for metal oxides - is also discussed. PMID:23030034

Jiang, Hao; Ma, Jan; Li, Chunzhong

2012-08-01

246

Multifunctional Magnetic Nanoparticles for Medical Imaging Applications  

PubMed Central

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.

Fang, Chen; Zhang, Miqin

2010-01-01

247

Targeting the brain with PEG-PLGA nanoparticles modified with phage-displayed peptides  

PubMed Central

The relative impermeability of the blood-brain barrier (BBB) results from tight junctions and efflux transport systems limits drug delivery to the central nervous system (CNS), and thus severely restricts the therapy of many central nervous system diseases. In order to enhance the brain-specific drug delivery, we employed a 12-mer phage display peptide library to isolate peptides that could target the drug delivery system to the brain. A 12-amino-acid-peptide (denoted as Pep TGN) which was displayed by bacteriophage Clone 12-2 was finally selected by rounds of in vivo screening. Pep TGN was covalently conjugated onto the surface of poly (ethyleneglycol)-poly (lactic-co-glycolic acid) (PEG-PLGA) based nanoparticles (NPs). The cellular uptake of Pep TGN decorated nanoparticles was significantly higher than that of unmodified nanoparticles when incubated with bEnd.3 cells. Enhanced brain accumulation efficiency together with lower accumulation in liver and spleen was observed in the nude mice intravenously injected with Pep TGN conjugated nanoparticles compared with those injected with plain nanoparticles, showing powerful brain selectivity of Pep TGN. Coumarin 6 was used as a fluorescent probe for the evaluation of brain delivery properties. The brain Drug Targeting Index (DTI) of coumarin 6 incorporated in targeted nanoparticles was significantly higher than that of coumarin 6 incorporated in plain nanoparticles. In conclusion, the Pep TGN is a motif never been reported before and Pep TGN modified nanoparticles showed great potential in targeted drug delivery across the blood brain barrier.

Li, Jingwei; Feng, Liang; Fan, Li; Zha, Yuan; Guo, Liangran; Zhang, Qizhi; Chen, Jun; Pang, Zhiqing; Wang, Yuchen; Jiang, Xinguo; Yang, Victor C.; Wen, Longping

2011-01-01

248

Latex nanoparticles for multimodal imaging and detection in vivo  

NASA Astrophysics Data System (ADS)

The aim of the present work was to develop a multimodal imaging and detection approach to study the behaviour of nanoparticles in animal studies. Highly carboxylated 144 nm-sized latex nanoparticles were labelled with 68Ga for positron emission tomography, 111In for quantitative gamma scintigraphy or Gd3+ for magnetic resonance imaging. Following intravenous injection into rats, precise localization was achieved revealing the tracer in the blood compartment with a time-dependent accumulation in the liver. In addition, rhodamine B was also incorporated to examine specific interactions with blood cells. Flow cytometry and fluorescent microscopy show uptake of nanoparticles by leucocytes and, unexpectedly, thrombocytes, but not erythrocytes. Cellular internalization was an active and selective process. Further incorporation of polyethylene glycol into the nanoparticle corona could prevent uptake by thrombocytes but not macrophages or monocytes. Our data demonstrate the feasibility of a multimodal approach and its usefulness to analyse the fate of nanoparticles at the macroscopic and cellular level. It will facilitate the development of functionalized nanocarrier systems and extend their biomedical applications.

Cartier, R.; Kaufner, L.; Paulke, B. R.; Wüstneck, R.; Pietschmann, S.; Michel, R.; Bruhn, H.; Pison, U.

2007-05-01

249

Covalently functionalized gold nanoparticles: Synthesis, characterization, and integration into capillary electrophoresis  

NASA Astrophysics Data System (ADS)

Nanomaterials are widely used as pseudostationary and stationary phases in electrically driven separations. The advantages of using nanomaterials are numerous including tunable sizes, multiple core compositions, flexible injection schemes, and diverse surface chemistries. Nanomaterials, however, exhibit large surface energies which induce aggregation and may yield unpredictable function in separations. Because nanomaterials can modify buffer conductivity, viscosity, and pH; successful and systematic incorporation of nanomaterials into separations requires rigorous synthetic control and characterization of both the nanoparticle core and surface chemistry. This dissertation investigates the impact of gold nanoparticle surface chemistry and morphology to capillary electrophoresis separations. Gold nanoparticle core composition, shape, size, self assembled monolayer (SAM) formation, and SAM packing density are quantified for gold nanoparticles functionalized with thioctic acid, 6-mercaptohexanoic acid, or 11-mercaptoundecanoic acid SAMs. TEM, 1H NMR, extinction spectroscopy, zeta potential, X-ray photoelectron spectroscopy, and flocculation assess the morphology, surface chemistry, optical properties, surface charge, SAM packing density, and stability of the nanoparticles, respectively. Using well-characterized nanostructures, pseudostationary phases of gold nanoparticles in capillary electrophoresis are studied. Gold nanoparticles functionalized with thioctic acid and either 6-mercaptohexanoic acid or 6-aminohexanethiol impact the mobility of analytes in a concentration and surface chemistry-dependent manner. From these data, a novel parameter termed the critical nanoparticle concentration is developed and is used to estimate nanoparticle stability during capillary electrophoresis separations. To understand the function of carboxylated gold nanoparticles in capillary electrophoresis, extended DLVO theory is used to model interparticle interactions. Nanoparticle aggregation leads to electron tunneling between nanoparticles thereby taking on bulk electrical properties which cause measured currents to increase for nanoparticles functionalized with poorly ordered SAMs. Nanoparticles functionalized with well-ordered SAMs main their nanoscale properties and reduce measured currents during electrically driven flow. Finally, carboxylic acid functionalized gold nanoparticles effect the separation of target biomarkers in both a SAM composition and surface coverage dependent manner. These effects are most systematic with well ordered SAMs. To understand the separation mechanism functionalized gold nanoparticles exhibit, their ? potential with and without dopamine are evaluated. Large dopamine concentrations neutralize the three functionalized gold nanoparticles according to a dose response curve. The positively charged dopamine molecules saturate the negatively charged nanoparticle surfaces thereby providing a plausible explanation to the observed biomarker concentration trends. These data and future work provide a rigorous experimental and theoretical evaluation of nanoparticle structure impacts their function as pseudostationary phases in separations and other applications.

Ivanov, Michael Robert

250

Targeting nanoparticles to cancer.  

PubMed

Nanotechnology applications in medicine, termed as nanomedicine, have introduced a number of nanoparticles of variable chemistry and architecture for cancer imaging and treatment. Nanotechnology involves engineering multifunctional devices with dimensions at the nanoscale, similar dimensions as those of large biological vesicles or molecules in our body. These devices typically have features just tens to hundred nanometers across and they can carry one or two detection signals and/or therapeutic cargo(s). One unique class of nanoparticles is designed to do both, providing this way the theragnostic nanoparticles (therapy and diagnosis). Being inspired by physiologically existing nanomachines, nanoparticles are designed to safely reach their target and specifically release their cargo at the site of the disease, this way increasing the drug's tissue bioavailability. Nanoparticles have the advantage of targeting cancer by simply being accumulated and entrapped in tumours (passive targeting). The phenomenon is called the enhanced permeation and retention effect, caused by leaky angiogenetic vessels and poor lymphatic drainage and has been used to explain why macromolecules and nanoparticles are found at higher ratios in tumours compared to normal tissues. Although accumulation in tumours is observed cell uptake and intracellular drug release have been questioned. Polyethyleneglycol (PEG) is used to protect the nanoparticles from the Reticulo-Endothelial System (RES), however, it prevents cell uptake and the required intracellular drug release. Grafting biorecognition molecules (ligands) onto the nanoparticles refers to active targeting and aims to increase specific cell uptake. Nanoparticles bearing these ligands are recognised by cell surface receptors and this leads to receptor-mediated endocytosis. Several materials are suggested for the design of nanoparticles for cancer. Polymers, linear and dendrimers, are associated with the drug in a covalent or non-covalent way and have been used with or without a targeting ligand. Stealth liposomes are suggested to carry the drug in the aqueous core, and they are usually decorated by recognition molecules, being widely studied and applied. Inorganic nanoparticles such as gold and iron oxide are usually coupled to the drug, PEG and the targeting ligand. It appears that the PEG coating and ligand decoration are common constituents in most types of nanoparticles for cancer. There are several examples of successful cancer diagnostic and therapeutic nanoparticles and many of them have rapidly moved to clinical trials. Nevertheless there is still a room for optimisation in the area of the nanoparticle kinetics such as improving their plasma circulation and tumour bioavailability and understanding the effect of targeting ligands on their efficiency to treat cancer. The need to develop novel and efficient ligands has never been greater, and the use of proper conjugation chemistry is mandatory. PMID:20380880

Wang, M; Thanou, M

2010-04-07

251

Toxicology of nanoparticles.  

PubMed

While nanotechnology and the production of nanoparticles are growing exponentially, research into the toxicological impact and possible hazard of nanoparticles to human health and the environment is still in its infancy. This review aims to give a comprehensive summary of what is known today about nanoparticle toxicology, the mechanisms at the cellular level, entry routes into the body and possible impacts to public health. Proper characterisation of the nanomaterial, as well as understanding processes happening on the nanoparticle surface when in contact with living systems, is crucial to understand possible toxicological effects. Dose as a key parameter is essential in hazard identification and risk assessment of nanotechnologies. Understanding nanoparticle pathways and entry routes into the body requires further research in order to inform policy makers and regulatory bodies about the nanotoxicological potential of certain nanomaterials. PMID:21925220

Elsaesser, Andreas; Howard, C Vyvyan

2011-09-08

252

Magnetic interactions between nanoparticles  

PubMed Central

Summary We present a short overview of the influence of inter-particle interactions on the properties of magnetic nanoparticles. Strong magnetic dipole interactions between ferromagnetic or ferrimagnetic particles, that would be superparamagnetic if isolated, can result in a collective state of nanoparticles. This collective state has many similarities to spin-glasses. In samples of aggregated magnetic nanoparticles, exchange interactions are often important and this can also lead to a strong suppression of superparamagnetic relaxation. The temperature dependence of the order parameter in samples of strongly interacting hematite nanoparticles or goethite grains is well described by a simple mean field model. Exchange interactions between nanoparticles with different orientations of the easy axes can also result in a rotation of the sub-lattice magnetization directions.

Hansen, Mikkel Fougt; Frandsen, Cathrine

2010-01-01

253

Magnetic Nanoparticle Degradation in vivo Studied by Mössbauer Spectroscopy  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles belong to the most promising nanosized objects for biomedical applications. However, little is known about clearance of magnetic nanoparticles from the organism. In this work superparamagnetic iron oxide particles fluidMAG-ARA were injected into tail vein of mice at a dose of 17 mg per 20 g body weight. At various time intervals after the injection the mice were sacrificed and their organs collected. A Mössbauer study allowed to detect magnetic particles in the liver and spleen and showed the degradation of the particles with incorporation of exogenous iron into paramagnetic ferritin-like iron species.

Nikitin, Maxim; Gabbasov, Raul; Cherepanov, Valery; Chuev, Mikhail; Polikarpov, Mikhail; Panchenko, Vladislav; Deyev, Sergey

2010-12-01

254

Shear thinning of nanoparticle suspensions.  

SciTech Connect

Results of large scale non-equilibrium molecular dynamics (NEMD) 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. Here we present results for the shear rheology of spherical nanoparticles of size 5 to 20 times that of the solvent for a range of nanoparticle volume fractions and interactions. Results from NEMD simulations suggest that for strongly interacting nanoparticle that form a colloidal gel, the shear rheology of the suspension depends only weakly on the size of the nanoparticle, even for nanoparticles as small as 5 times that of the solvent. However for hard sphere-like colloids the size of the nanoparticles strongly affects the shear rheology. The shear rheology for dumbbell nanoparticles made of two fused spheres is also compared to spherical nanoparticles and found to be similar except at very high volume fractions.

Grest, Gary Stephen; Petersen, Matthew K.; in't Veld, Pieter J. (Polymer Research, Ludwigshafen, Germany)

2008-08-01

255

Functional Magnetic Nanoparticles  

NASA Astrophysics Data System (ADS)

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.

Gass, James

256

Magnetite-Alginate-AOT nanoparticles based drug delivery platform  

NASA Astrophysics Data System (ADS)

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.

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

2008-03-01

257

Molecular imaging with nanoparticles: giant roles for dwarf actors.  

PubMed

Molecular imaging, first developed to localise antigens in light microscopy, now encompasses all imaging modalities including those used in clinical care: optical imaging, nuclear medical imaging, ultrasound imaging, CT, MRI, and photoacoustic imaging. Molecular imaging always requires accumulation of contrast agent in the target site, often achieved most efficiently by steering nanoparticles containing contrast agent into the target. This entails accessing target molecules hidden behind tissue barriers, necessitating the use of targeting groups. For imaging modalities with low sensitivity, nanoparticles bearing multiple contrast groups provide signal amplification. The same nanoparticles can in principle deliver both contrast medium and drug, allowing monitoring of biodistribution and therapeutic activity simultaneously (theranostics). Nanoparticles with multiple bioadhesive sites for target recognition and binding will be larger than 20 nm diameter. They share functionalities with many subcellular organelles (ribosomes, proteasomes, ion channels, and transport vesicles) and are of similar sizes. The materials used to synthesise nanoparticles include natural proteins and polymers, artificial polymers, dendrimers, fullerenes and other carbon-based structures, lipid-water micelles, viral capsids, metals, metal oxides, and ceramics. Signal generators incorporated into nanoparticles include iron oxide, gadolinium, fluorine, iodine, bismuth, radionuclides, quantum dots, and metal nanoclusters. Diagnostic imaging applications, now appearing, include sentinal node localisation and stem cell tracking. PMID:18825403

Debbage, Paul; Jaschke, Werner

2008-09-30

258

Shaped gold and silver nanoparticles  

Microsoft Academic Search

Advance in the synthesis of shaped nanoparticles made of gold and silver is reviewed in this article. This review starts with\\u000a a new angle by analyzing the relationship between the geometrical symmetry of a nanoparticle shape and its internal crystalline\\u000a structures. According to the relationship, the nanoparticles with well-defined shapes are classified into three categories:\\u000a nanoparticles with single crystallinity, nanoparticles

Yugang Sun; Changhua An

2011-01-01

259

Biosynthetic incorporation of tryptophan analogs in proteins.  

PubMed

Biosynthetic incorporation of Trp analogs in a protein can help in its characterization using fluorescence spectroscopy and other methodologies like NMR and phosphorescence. Here a protocol is presented resulting in the efficient incorporation of Trp analogs in a recombinant protein, using an Escherichia coli Trp auxotroph. An overview of recent developments in the Trp analog incorporation field is also presented. PMID:24108634

Broos, Jaap

2014-01-01

260

Numeral Incorporation in Japanese Sign Language  

ERIC Educational Resources Information Center

|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…

Ktejik, Mish

2013-01-01

261

Tracer-incorporated X-ray imaging of biofluid flow phenomena  

NASA Astrophysics Data System (ADS)

Particle-traced X-ray imaging technologies have been developed by combining the merits of the X-ray radiography and particle image velocimetry (PIV) technique. The developed X-ray imaging technology has strong potential in the noninvasive analysis of various flows such as non-transparent fluid flows or fluids flowing in opaque conduits. In this study, tracer-incorporated X-ray imaging technology was developed. In addition, new- concepted tracer particles were designed for in vitro and in vivo X-ray imaging analysis of various biofluids. As tracer particles in X-ray image, X-ray contrast enhancer Iopamidol was encapsulated into bio-compatible polymeric chitosan microparticles and gold nanoparticles with high X-ray absorption efficiency were directly incorporated into cells. The Iopamidol-incorporated polymeric microparticles were successfully applied for in vivo blood flow measurement in a rat. The gold nanoparticles were selectively incorporated into cancer cells, by which cancer cells can be detected in situ. The developed X-ray imaging technology would have a great potential in biomedical applications such as in situ analysis of blood flow and cancer detection.

Jung, Sung Yong; Ahn, Sungsook; Lee, Sang Joon

2011-11-01

262

Novel ionically crosslinked casein nanoparticles for flutamide delivery: formulation, characterization, and in vivo pharmacokinetics.  

PubMed

A novel particulate delivery matrix based on ionically crosslinked casein (CAS) nanoparticles was developed for controlled release of the poorly soluble anticancer drug flutamide (FLT). Nanoparticles were fabricated via oil-in-water emulsification then stabilized by ionic crosslinking of the positively charged CAS molecules below their isoelectric point, with the polyanionic crosslinker sodium tripolyphosphate. With the optimal preparation conditions, the drug loading and incorporation efficiency achieved were 8.73% and 64.55%, respectively. The nanoparticles exhibited a spherical shape with a size below 100 nm and a positive zeta potential (+7.54 to +17.3 mV). FLT was molecularly dispersed inside the nanoparticle protein matrix, as revealed by thermal analysis. The biodegradability of CAS nanoparticles in trypsin solution could be easily modulated by varying the sodium tripolyphosphate crosslinking density. A sustained release of FLT from CAS nanoparticles for up to 4 days was observed, depending on the crosslinking density. After intravenous administration of FLT-CAS nanoparticles into rats, CAS nanoparticles exhibited a longer circulation time and a markedly delayed blood clearance of FLT, with the half-life of FLT extended from 0.88 hours to 14.64 hours, compared with drug cosolvent. The results offer a promising method for tailoring biodegradable, drug-loaded CAS nanoparticles as controlled, long-circulating drug delivery systems of hydrophobic anticancer drugs in aqueous vehicles. PMID:23658490

Elzoghby, Ahmed O; Helmy, Maged W; Samy, Wael M; Elgindy, Nazik A

2013-05-03

263

Ensemble learning incorporating uncertain registration.  

PubMed

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

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

2012-12-27

264

Preparation and characterization of novel coenzyme Q 10 nanoparticles engineered from microemulsion precursors  

Microsoft Academic Search

The purpose of these studies was to prepare and characterize nanoparticles into which Coenzyme Q10 (CoQ10) had been incorporated (CoQ10-NPs) using a simple and potentially scalable method. CoQ10-NPs were prepared by cooling warm microemulsion precursors composed of emulsifying wax, CoQ10, Brij 78, and\\/or Tween 20. The nanoparticles were lyophilized, and the stability of CoQ10-NPs in both lyophilized form and aqueous

Cheng-Hsuan Hsu; Zhengrong Cui; Russell J. Mumper; Michael Jay

2003-01-01

265

Enhancement of tumor thermal therapy using gold nanoparticle-assisted tumor necrosis factor-A delivery  

Microsoft Academic Search

Tumor necrosis factor-A (TNF-A) is a potent cytokine with anticancer efficacy that can significantly enhance hyper- thermic injury. However, TNF-A is systemically toxic, thereby creating a need for its selective tumor delivery. We used a newly developed nanoparticle delivery system consisting of 33-nm polyethylene glycol - coated colloidal gold nanoparticles (PT-cAu-TNF-A) with incorporated TNF-A payload (several hundred TNF-A molecules per

Rachana K. Visaria; Robert J. Griffin; Brent W. Williams; Emad S. Ebbini; Giulio F. Paciotti; Chang W. Song; John C. Bischof

2006-01-01

266

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

Microsoft Academic Search

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.

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

2002-01-01

267

Hydroxycamptothecin-loaded nanoparticles enhance target drug delivery and anticancer effect  

Microsoft Academic Search

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

Anxun Wang; Su Li

2008-01-01

268

PLGA Micro and Nanoparticles Loaded Into Gelatin Scaffold for Controlled Drug Release  

Microsoft Academic Search

Curcumin and bovine serum albumin (BSA) were used as model drugs and loaded into micro- and nanoparticles of biodegradable poly(lactic-co-glycolic acid) (PLGA). The PLGA was incorporated into hydrophilic and biocompatible gelatin scaffolds to design a controlled drug release system. The gelatin scaffolds were cross-linked using glutaraldehyde. The controlled delivery of drugs from biologically active PLGA micro- and nanoparticles was measured

Waseem Asghar; Muhymin Islam; Aniket S. Wadajkar; Yuan Wan; Azhar Ilyas; Kytai T. Nguyen; Samir M. Iqbal

2012-01-01

269

Preparation and characterisation of rose Bengal-loaded surface-modified albumin nanoparticles  

Microsoft Academic Search

Surface-modified albumin nanoparticles were prepared from two poly(ethylene glycol)–human serum albumin conjugates: poly(thioetheramido acid)–poly(ethylene glycol) copolymer-grafted HSA (HSA–PTAAC–PEG) and methoxy poly(ethylene glycol)-grafted HSA (HSA–mPEG). Rose bengal (RB) was used as a model drug for encapsulation into the nanoparticles either during the particle production or by adsorption post particle preparation. The drug incorporation and release was affected by the different production

Wu Lin; Martin C. Garnett; Stanley S. Davis; Etienne Schacht; Paulo Ferruti; Lisbeth Illum

2001-01-01

270

Enhancement of the near-band-edge photoluminescence of ZnO nanowires: Important role of hydrogen incorporation versus plasmon resonances  

NASA Astrophysics Data System (ADS)

We investigated the photoluminescence properties of ZnO nanowires coated with Au, Ag, and Pt nanoparticles deposited by dc sputtering. A strong enhancement of the near-band-edge emission was observed in all metal-coated samples but also if the samples were treated with Ar plasma without any nanoparticle deposition. High-resolution photoluminescence spectroscopy revealed hydrogen-donor-bound-exciton emission in all samples indicating unintentional hydrogen incorporation. A shorter decay time of the near-band-edge emission was observed in all cases. The results indicate that unintentional hydrogen incorporation plays a dominant role when metal deposition is performed by sputtering.

Dev, A.; Richters, J. P.; Sartor, J.; Kalt, H.; Gutowski, J.; Voss, T.

2011-03-01

271

Dynamics of nanoparticle adhesion  

NASA Astrophysics Data System (ADS)

We performed molecular dynamics simulations and theoretical analysis of nanoparticle pulling off from adhesive substrates. Our theoretical model of nanoparticle detachment is based on the Kramers' solution of the stochastic barrier crossing in effective one-dimensional potential well. The activation energy, ?E, for nanoparticle detachment first decreases linearly with increasing the magnitude of the applied force, f, then it follows a power law ?E ~ (f* - f)3/2 as magnitude of the pulling force f approaches a critical detachment force value, f*. These two different regimes in activation energy dependence on magnitude of the applied force are confirmed by analyzing nanoparticle detachment in effective one-dimensional potential obtained by weighted histogram analysis method. Simulations show that detachment of nanoparticle proceeds through neck formation such that magnitude of the activation energy is determined by balancing surface energy of the neck connecting particle to a substrate with elastic energy of nanoparticle deformation. In this regime the activation energy at zero applied force, ?E0, for nanoparticle with radius, Rp, shear modulus, G, surface energy, ?p, and work of adhesion, W, is a universal function of the dimensionless parameter ? ~?pW-2/3(GRp)-1/3. Simulation data are described by a scaling function ?E0~?p5/2Rp1/2G-3/2?-3.75. Molecular dynamics simulations of nanoparticle detachment show that the Kramers' approach fails in the vicinity of the critical detachment force f* where activation energy barrier becomes smaller than the thermal energy kBT. In the interval of the pulling forces f > f* nanoparticle detachment becomes a deterministic process.

Carrillo, Jan-Michael Y.; Dobrynin, Andrey V.

2012-12-01

272

Dynamics of nanoparticle adhesion.  

PubMed

We performed molecular dynamics simulations and theoretical analysis of nanoparticle pulling off from adhesive substrates. Our theoretical model of nanoparticle detachment is based on the Kramers' solution of the stochastic barrier crossing in effective one-dimensional potential well. The activation energy, ?E, for nanoparticle detachment first decreases linearly with increasing the magnitude of the applied force, f, then it follows a power law ?E [proportionality] (f* - f)(3/2) as magnitude of the pulling force f approaches a critical detachment force value, f*. These two different regimes in activation energy dependence on magnitude of the applied force are confirmed by analyzing nanoparticle detachment in effective one-dimensional potential obtained by weighted histogram analysis method. Simulations show that detachment of nanoparticle proceeds through neck formation such that magnitude of the activation energy is determined by balancing surface energy of the neck connecting particle to a substrate with elastic energy of nanoparticle deformation. In this regime the activation energy at zero applied force, ?E(0), for nanoparticle with radius, R(p), shear modulus, G, surface energy, ?(p), and work of adhesion, W, is a universal function of the dimensionless parameter ? [proportionality] ?(p)W(-2/3)(GR(p))(-1/3). Simulation data are described by a scaling function ?E(0) [proportionality] ?(p) (5/2)R(p)(1/2)G(-3/2)?(-3.75). Molecular dynamics simulations of nanoparticle detachment show that the Kramers' approach fails in the vicinity of the critical detachment force f* where activation energy barrier becomes smaller than the thermal energy k(B)T. In the interval of the pulling forces f > f* nanoparticle detachment becomes a deterministic process. PMID:23231258

Carrillo, Jan-Michael Y; Dobrynin, Andrey V

2012-12-01

273

Modeling of enhanced absorption and Raman scattering caused by plasmonic nanoparticle near fields  

NASA Astrophysics Data System (ADS)

By assuming a simple dipole approximation for the plasmonic response of small metallic nanoparticles, we derive close-form analytical expressions for the overall absorption enhancement and Raman scattering enhancement expected in the material filling the space around them. Ohmic losses inside the nanoparticles as well as inter-nanoparticle plasmon coupling effects are incorporated in the model. A comparison with accurate numerical simulations shows excellent agreement for a wide range of nanoparticle volume filling ratios, core/shell geometries, and even in the case of mixing different types of metals. Even though a simplified geometry without interfaces has been adopted in these derivations, our expressions nevertheless are intuitive and can become great tools in understanding, designing and optimizing nanoparticle-based plasmonic devices.

Lidorikis, Elefterios

2012-12-01

274

Design parameters for voltage-controllable directed assembly of single nanoparticles.  

PubMed

Techniques to reliably pick-and-place single nanoparticles into functional assemblies are required to incorporate exotic nanoparticles into standard electronic circuits. In this paper we explore the use of electric fields to drive and direct the assembly process, which has the advantage of being able to control the nano-assembly process at the single nanoparticle level. To achieve this, we design an electrostatic gating system, thus enabling a voltage-controllable nanoparticle picking technique. Simulating this system with the nonlinear Poisson-Boltzmann equation, we can successfully characterize the parameters required for single particle placement, the key being single particle selectivity, in effect designing a system that can achieve this controllably. We then present the optimum design parameters required for successful single nanoparticle placement at ambient temperature, an important requirement for nanomanufacturing processes. PMID:24029752

Porter, Benjamin F; Abelmann, Leon; Bhaskaran, Harish

2013-09-12

275

Synthesis, antibacterial and thermal studies of cellulose nanocrystal stabilized ZnO-Ag heterostructure nanoparticles.  

PubMed

Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs) as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO? relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag heterostructure nanoparticles have spherical shapes with size diameters in a 9-35 nm range. The antibacterial activities of samples were assessed against the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The CNC-stabilized ZnO-Ag exhibited greater bactericidal activity compared to cellulose-free ZnO-Ag heterostructure nanoparticles of the same particle size. The incorporation of ZnO-Ag hetreostructure nanoparticles significantly increased the thermal stability of cellulose nanocrystals. PMID:23760028

Azizi, Susan; Ahmad, Mansor Bin Hj; Hussein, Mohd Zobir; Ibrahim, Nor Azowa

2013-05-28

276

Nanoparticle delivery systems for cancer therapy: advances in clinical and preclinical research.  

PubMed

Conventional anticancer drugs display significant shortcomings which limit their use in cancer therapy. For this reason, important progress has been achieved in the field of nanotechnology to solve these problems and offer a promising and effective alternative for cancer treatment. Nanoparticle drug delivery systems exploit the abnormal characteristics of tumour tissues to selectively target their payloads to cancer cells, either by passive, active or triggered targeting. Additionally, nanoparticles can be easily tuned to improve their properties, thereby increasing the therapeutic index of the drug. Liposomes, polymeric nanoparticles, polymeric micelles and polymer- or lipid-drug conjugate nanoparticles incorporating cytotoxic therapeutics have been developed; some of them are already on the market and others are under clinical and preclinical research. However, there is still much research to be done to be able to defeat the limitations of traditional anticancer therapy. This review focuses on the potential of nanoparticle delivery systems in cancer treatment and the current advances achieved. PMID:22301396

Egusquiaguirre, Susana Patricia; Igartua, Manuela; Hernández, Rosa María; Pedraz, José Luis

2012-02-01

277

Long-circulating near-infrared fluorescent nanoparticles for diagnosis and photodynamic therapy of cutaneous cancers  

NASA Astrophysics Data System (ADS)

Indocyanine green (ICG) is a near-infrared fluorescence contrast agent, which has enormous potential in early tumor diagnosis and therapy. The objective of this study is to develop biodegradable nanoparticles entrapping ICG and to characterize its intracellular uptake and photodynamic activity in different cancer cell lines. Nanoparticles entrapping ICG were engineered, characterized and the intracellular uptake of ICG was investigated in B16-F10 and C-33A cancer cell lines. The photodynamic activity of ICG-loaded nanoparticles was also investigated. The nanoparticles enhanced the intracellular uptake of ICG and showed significant photodynamic activity, especially at very low ICG concentrations. These preliminary studies indicate the potential of efficient tumor cell delivery and tumoricidal effect of ICG when incorporated in nanoparticles.

Saxena, Vishal; Sadoqi, Mostafa; Kumar, S.; Shao, Jun

2004-07-01

278

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

PubMed Central

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.

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

2013-01-01

279

Design parameters for voltage-controllable directed assembly of single nanoparticles  

NASA Astrophysics Data System (ADS)

Techniques to reliably pick-and-place single nanoparticles into functional assemblies are required to incorporate exotic nanoparticles into standard electronic circuits. In this paper we explore the use of electric fields to drive and direct the assembly process, which has the advantage of being able to control the nano-assembly process at the single nanoparticle level. To achieve this, we design an electrostatic gating system, thus enabling a voltage-controllable nanoparticle picking technique. Simulating this system with the nonlinear Poisson-Boltzmann equation, we can successfully characterize the parameters required for single particle placement, the key being single particle selectivity, in effect designing a system that can achieve this controllably. We then present the optimum design parameters required for successful single nanoparticle placement at ambient temperature, an important requirement for nanomanufacturing processes.

Porter, Benjamin F.; Abelmann, Leon; Bhaskaran, Harish

2013-10-01

280

Electrical, thermophysical and micromechanical properties of ethylene-vinyl acetate elastomer composites with surface modified BaTiO3 nanoparticles  

Microsoft Academic Search

In this study, we investigated the influence of the surface modified BaTiO3 nanoparticles on the electrical, thermophysical and micromechanical properties of ethylene-vinyl acetate (EVM) vulcanizates. Gamma-aminopropyl triethoxysilane was used as a silane coupling agent for the surface treatment of the BaTiO3 nanoparticles. It was found that the incorporation of surface modified BaTiO3 nanoparticles into the EVM matrix not only increased

Xingyi Huang; Liyuan Xie; Pingkai Jiang; Genlin Wang; Fei Liu

2009-01-01

281

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

SciTech Connect

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.

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

2010-08-23

282

Facile one-pot synthesis of gold nanoparticles stabilized with bifunctional amino/siloxy ligands  

SciTech Connect

A method for the direct one-pot synthesis of amine-stabilized gold nanoparticles using 3-(trimethoxysilylpropyl)diethylenetriamine (TMSP dien) is described. The amine groups of this bifunctional molecule act as a stabilizer for gold nanoparticles as they form by reduction of HAuCl{sub 4}. Highly stable gold nanoparticles with sizes tunable between 8 and 20 nm can be readily obtained. This method is quite simple to implement and environmentally benign as there is no need to add an external reducing reagent. The incorporated siloxy functionality was subsequently used to form a silica shell around the gold particle.

Zhu, Haoguo [ORNL; Pan, Zhengwei [ORNL; Hagaman, Edward {Ed} W [ORNL; Liang, Chengdu [ORNL; Overbury, Steven {Steve} H [ORNL; Dai, Sheng [ORNL

2005-01-01

283

Nanoparticle-induced negative differential resistance and memory effect in polymer bistable light-emitting device  

NASA Astrophysics Data System (ADS)

Recently, electrical bistability was demonstrated in polymer thin films incorporated with metal nanoparticles [J. Ouyang, C. W. Chu, C. R. Szmanda, L. P. Ma, and Y. Yang, Nat. Mater. 3, 918 (2004)]. In this letter, we show the evidence that electrons are the dominant charge carriers in these bistable devices. Direct integration of bistable polymer layer with a light-emitting polymer layer shows a unique light-emitting property modulated by the electrical bistability. A unique negative differential resistance induced by the charged gold nanoparticles is observed due to the charge trapping effect from the nanoparticles when interfaced with the light-emitting layer.

Tseng, Ricky J.; Ouyang, Jianyong; Chu, Chih-Wei; Huang, Jinsong; Yang, Yang

2006-03-01

284

Fabrication, Modeling and Characterization of Multi-Crosslinked Methacrylate Copolymeric Nanoparticles for Oral Drug Delivery  

PubMed Central

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.

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

285

Liposomes: from a clinically established drug delivery system to a nanoparticle platform for theranostic nanomedicine.  

PubMed

For decades, clinicians have used liposomes, self-assembled lipid vesicles, as nanoscale systems to deliver encapsulated anthracycline molecules for cancer treatment. The more recent proposition to combine liposomes with nanoparticles remains at the preclinical development stages; however, such hybrid constructs present great opportunities to engineer theranostic nanoscale delivery systems, which can combine simultaneous therapeutic and imaging functions. Many novel nanoparticles of varying chemical compositions are being developed in nanotechnology laboratories, but further chemical modification is often required to make these structures compatible with the biological milieu in vitro and in vivo. Such nanoparticles have shown promise as diagnostic and therapeutic tools and generally offer a large surface area that allows covalent and non-covalent surface functionalization with hydrophilic polymers, therapeutic moieties, and targeting ligands. In most cases, such surface manipulation diminishes the theranostic properties of nanoparticles and makes them less stable. From our perspective, liposomes offer structural features that can make nanoparticles biocompatible and present a clinically proven, versatile platform for further enhancement of the pharmacological and diagnostic efficacy of nanoparticles. In this Account, we describe two examples of liposome-nanoparticle hybrids developed as theranostics: liposome-quantum dot hybrids loaded with a cytotoxic drug (doxorubicin) and artificially enveloped adenoviruses. We incorporated quantum dots into lipid bilayers, which rendered them dispersible in physiological conditions. This overall vesicular structure allowed them to be loaded with doxorubicin molecules. These structures exhibited cytotoxic activity and labeled cells both in vitro and in vivo. In an alternative design, lipid bilayers assembled around non-enveloped viral nanoparticles and altered their infection tropism in vitro and in vivo with no chemical or genetic capsid modifications. Overall, we have attempted to illustrate how alternative strategies to incorporate nanoparticles into liposomal nanostructures can overcome some of the shortcomings of nanoparticles. Such hybrid structures could offer diagnostic and therapeutic combinations suitable for biomedical and even clinical applications. PMID:21812415

Al-Jamal, Wafa' T; Kostarelos, Kostas

2011-08-03

286

Self-assembled nanoparticles of hydrophobically-modified polysaccharide bearing vitamin H as a targeted anti-cancer drug delivery system  

Microsoft Academic Search

Vitamin H (biotin) was incorporated into a hydrophobically modified polysaccharide, pullulan acetate (PA), in order to improve the cancer-targeting activity and internalization of self-assembled nanoparticles. The biotinylated pullulan acetate (BPA) nanoparticles were prepared by a diafiltration method and the mean diameter was approximately 100 nm. Three samples of biotinylated pullulan acetate (BPA), comprising 7 (BPA 1), 20 (BPA 2), and

Kun Na; Tae Bum Lee; Keun-Hong Park; Eun-Kyung Shin; Yong-Bok Lee; Hoo-Kyun Choi

2003-01-01

287

Combination of chemopreventive agents in nanoparticles for cancer prevention.  

PubMed

Carcinogenesis involves multiple genetic and epigenetic alterations, and a single chemopreventive agent may not be sufficient to prevent these events. Therefore, the use of a combination of agents is an attractive approach for cancer chemoprevention. In this issue of the journal, Prabhu and colleagues examined a combination of aspirin, curcumin, and sulforaphane for the prevention of pancreatic cancer in hamsters (beginning page 1015). The novelty of this work is that when aspirin and curcumin were incorporated in nanoparticles and administered orally, in combination with sulforaphane, the effective dosages were decreased by 10-fold in comparison with the free form mixture. In this commentary, the possible mechanisms of synergistic action among multiple chemopreventive agents and the use of stable nanoparticles for oral delivery are discussed. Also discussed is the importance of measuring tissue levels of the chemopreventive agents to understand the mode of action of these nanoparticles and to avoid toxicity. Cancer Prev Res; 6(10); 1011-4. ©2013 AACR. PMID:24072675

Yang, Chung S; Wang, Hong; Hu, Bing

2013-09-26

288

Electrosprayed nanoparticles for drug delivery and pharmaceutical applications  

PubMed Central

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.

Sridhar, Radhakrishnan; Ramakrishna, Seeram

2013-01-01

289

Magnetic conjugated polymer nanoparticles as bimodal imaging agents.  

PubMed

Hybrid nanoparticles which incorporate multiple functionalities, such as fluorescence and magnetism, can exhibit enhanced efficiency and versatility by performing several tasks in parallel. In this study, magnetic-fluorescent semiconductor polymer nanospheres (MF-SPNs) have been synthesized by encapsulation of hydrophobic conjugated polymers and iron oxide nanoparticles in phospholipid micelles. Four fluorescent conjugated polymers were used, yielding aqueous dispersions of nanoparticles which emit across the visible spectrum. The MF-SPNs were shown to be magnetically responsive and simultaneously fluorescent. In MRI studies, they were seen to have a shortening effect on the transverse T(2)* relaxation time, which demonstrates their potential as an MR contrast agent. Finally, successful uptake of the MF-SPNs by SH-SY5Y neuroblastoma cells was demonstrated, and they were seen to behave as bright and stable fluorescent markers. There was no evidence of toxicity or adverse affect on cell growth. PMID:20572665

Howes, Philip; Green, Mark; Bowers, Alex; Parker, David; Varma, Gopal; Kallumadil, Mathew; Hughes, Mary; Warley, Alice; Brain, Anthony; Botnar, Rene

2010-07-21

290

Poly(amino acid) functionalized maghemite and gold nanoparticles  

NASA Astrophysics Data System (ADS)

Bimodal MRI/OI imaging probes are of great interest in nanomedicine. Although many organic polymers have been studied thoroughly for in vivo applications, reports on the use of poly(amino acid)s as coating polymers are scarce. In this paper, poly-(d-glutamic acid, d-lysine) (PGL) has been used for coating maghemite and gold nanoparticles. An advantage of this flexible and biocompatible polymer is that, once anchored to the nanoparticle surface, dangling lysine amino groups are available for the incorporation of new functionalities. As an example, Alexa Fluor derivatives have been attached to PGL-coated maghemite nanoparticles to obtain magnetic/fluorescent materials. These dual-property materials could be used as bimodal MRI/OI probes for in vivo imaging.

Perego, Davide; Masciocchi, Norberto; Guagliardi, Antonietta; Domínguez-Vera, José Manuel; Gálvez, Natividad

2013-02-01

291

Microdosimetry of X-ray-irradiated gold nanoparticles.  

PubMed

The use of contrast agents, particularly those made of high atomic number elements like gold nanoparticles, to enhance the X-ray absorption properties of tissue has recently gained attention in the context of radiotherapy treatments. Because these contrast agents alter the secondary electron field in the irradiated medium by adding an Auger electron component, it is necessary to determine the change in the microdosimetric spectra brought about by the incorporation of such agents. Using Monte Carlo simulation, it is shown that the linear energy transfer and the beam quality factor in the vicinity of a gold nanoparticle irradiated with kilovoltage X-ray beams increase substantially when compared with irradiation without the gold nanoparticles present. PMID:23118439

Garnica-Garza, H M

2012-10-31

292

Toxicity of therapeutic nanoparticles.  

PubMed

A total of six nanotherapeutic formulations are already approved for medical use and more are in the approval pipeline currently. Despite the massive research effort in nanotherapeutic materials, there is relatively little information about the toxicity of these materials or the tools needed to assess this toxicity. Recently, the scientific community has begun to respond to the paucity of information by investing in the field of nanoparticle toxicology. This review is intended to provide an overview of the techniques needed to assess toxicity of these therapeutic nanoparticles and to summarize the current state of the field. We begin with background on the toxicological assessment techniques used currently as well as considerations in nanoparticle dosing. The toxicological research overview is divided into the most common applications of therapeutic nanoparticles: drug delivery, photodynamic therapy and bioimaging. We end with a perspective section discussing the current technological gaps and promising research aimed at addressing those gaps. PMID:19193187

Maurer-Jones, Melissa A; Bantz, Kyle C; Love, Sara A; Marquis, Bryce J; Haynes, Christy L

2009-02-01

293

Engines and nanoparticles  

Microsoft Academic Search

Most of the particle number emitted by engines is in the nanoparticle range, Dp<50 nm, while most of the mass is in the accumulation mode, 50nmNanoparticles are typically hydrocarbons or sulfate and form by nucleation during dilution and cooling of the exhaust, while accumulation mode particles are mainly carbonaceous soot agglomerates formed directly by combustion. Emission standards

David B. Kittelson

1998-01-01

294

Introduction to metallic nanoparticles  

PubMed Central

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.

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

2010-01-01

295

Recovery of nanoparticles produced in phosphatidylcholine-based template phases.  

PubMed

This paper focuses on the characterization and use of polymer-modified phosphatidylcholine (PC)/sodium dodecyl sulfate (SDS)-based inverse microemulsions as a template phase for BaSO4 nanoparticle formation. The area of the optically clear inverse microemulsion phase in the isooctane/hexanol/water/PC/SDS system is not significantly changed by adding polyelectrolytes, i.e., poly(diallyldimethylammonium chloride) (PDADMAC), or amphoteric copolymers of diallyldimethylammonium chloride and maleamid acid to the SDS-modified inverse microemulsion. Shear experiments show non-Newtonian flow behavior and oscillation experiments show a frequency-dependent viscosity increase (dilatant behavior) of the microemulsions. Small amounts of bulk water were identified by means of differential scanning calorimetry. One can conclude that the macromolecules are incorporated into the individual droplets, and polymer-filled microemulsions are formed. The polymer-filled microemulsions were used as a template phase for the synthesis of BaSO4 nanoparticles. After solvent evaporation the nanoparticles were redispersed in water and isooctane, respectively. The polymers incorporated into the microemulsion are involved in the redispersion process and influence the size and shape of the redispersed BaSO4 particles in a specific way. The crystallization process mainly depends on the type of solvent and the polymer component added. In the presence of the cationic polyelectrolyte PDADMAC the crystallization to larger cubic crystals is inhibited, and layers consisting of polymer-stabilized spherical nanoparticles of BaSO4 (6 nm in size) will be observed. PMID:15752801

Koetz, J; Reichelt, S; Kosmella, S; Tiersch, B

2005-04-01

296

Mixed Ni/Co hydroxide nanoparticles synthesized by sonochemical method.  

PubMed

Nickel hydroxide nanoparticles with different amounts of cobalt atoms in the structure forming a unique material, were synthesized by using ultrasonic radiation. The particles of 5 nm diameter were prepared and characterized by X-Ray diffraction, Raman and Infrared spectroscopies, and thermogravimetry. The incorporation of cobalt leads to distinct crystalline planes, showing an opened and disarranged structure, indicating the stabilization of the alpha-Ni(OH)2 phase. PMID:18019153

Vidotti, Marcio; Salvador, Renan P; Ponzio, Eduardo A; Córdoba de Torresi, Susana I

2007-09-01

297

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

NSDL National Science Digital Library

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.

Livenere, John

2009-08-15

298

A novel approach to the synthesis of hollow silica nanoparticles  

Microsoft Academic Search

Hollow silica nanoparticles were synthesized with incorporation of silanol groups (SiOH) onto polymer particles in dispersion polymerization and the polycondensation reaction of tetraethyl orthosilicate (TEOS) exclusively took place at the particles surface in the presence of ammonia following the so-called Stöber process and the silica-coated polymer powers were calcined at 800 °C. The diameters of hollow silica spheres are found

Xuefeng Ding; Kaifeng Yu; Yanqiu Jiang; Hari-Bala; Hengbin Zhang; Zichen Wang

2004-01-01

299

Magnetic Nanoparticle Compositions and Methods.  

National Technical Information Service (NTIS)

A nanoparticle having a core comprising a magnetic material and surface to which are covalently coupled a plurality of silane moieties, wherein each silane moiety comprises a polyalkylene oxide moiety. The nanoparticle can further include a targeting agen...

J. W. Gunn M. Zhang N. Kohler

2006-01-01

300

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...

301

Fluorescence from Coated Oxide Nanoparticles.  

National Technical Information Service (NTIS)

In many cases, coated nanoparticles behave like isolated ones. Using the microwave plasma process, it is possible to produce oxide nanoparticles with ceramic or polymer coating. Coating the particles has the additional advantage that by proper selection o...

D. Vollath D. V. Szabo I. Lamparth

2001-01-01

302

Transport measurements across single nanoparticles  

NASA Astrophysics Data System (ADS)

During this last decade, numerous progresses have been obtained in the chemical synthesis of nanoparticle. Various materials (oxides, chalcogenides) known for their peculiar electronic or magnetic properties -- superconductivity, Mott localization, topological protection -- can now be obtained as nanoparticles through chemical synthesis. These new nano-materials are offering a unique opportunity to study the effect of quantum confinement on unconventional electronic orders. To improve the preparation of samples with single nanoparticles trapped within a nanogap, we developed a new method where nanoparticles are projected in-vacuum on chip circuits covered by nanogap spaced electrodes. Continuous current measurements during the projection allow identifying the trapping of a single nanoparticle within the nanogap. We apply the method for trapping single gold nanoparticles, which led to the observation of Coulomb blockade. We also applied the method to magnetite (Fe3O4) nanoparticles, which allows to study the electric field induced insulator to metal transition in only a few nanoparticles.

Yu, Qian; Cui, Limin; Ulysse, Christian; Mottaghizadeh, Alireza; Zimmers, Alexandre; Aubin, Hervé.

2013-03-01

303

Enhancement of surface ligand display on PLGA nanoparticles with amphiphilic ligand conjugates  

PubMed Central

Biodegradable polymeric nanoparticles are widely recognized as efficacious drug delivery vehicles, yet the rational engineering of nanoparticle surfaces in order to improve biodistribution, reduce clearance, and/or improve targeting remains a significant challenge. We have previously demonstrated that an amphiphilic conjugate of avidin and palmitic acid can be used to modify poly(lactic-co-glycolic acid) (PLGA) particle surfaces to display functional avidin groups, allowing for the facile attachment of biotinylated ligands for targeting or steric stabilization. Here, we hypothesized that the incorporation, density, and stability of surface-presented avidin could be modulated through varying the lipophilicity of its fatty acid conjugate partner. We tested this hypothesis by generating a set of novel conjugates incorporating avidin and common fatty acids. We found that conjugation to linoleic acid resulted in a ?60% increase in the incorporation of avidin on the nanoparticle surface compared to avidin–palmitic acid, which exhibited the highest avidin incorporation in previous studies. Further, the linoleic acid–avidin conjugate yielded nanoparticles with enhanced ability to bind biotinylated ligands compared to the previous method; nanoparticles modified with avidin–linoleic acid bound ?170% more biotin–HRP than those made with avidin–palmitic acid and ?1300% more than particles made without conjugated avidin. Most critically, increased ligand density on anti-CD4-targeted nanoparticles formulated with the linoleic acid–avidin conjugate resulted in a 5% increase in binding of CD4+ T cells. Thus we conclude that the novel avidin–linoleic acid conjugate facilitates enhanced ligand density on PLGA nanoparticles, resulting in functional enhancement of cellular targeting.

Park, Jason; Mattessich, Thomas; Jay, Steven M.; Agawu, Atu; Saltzman, W. Mark; Fahmy, Tarek M.

2013-01-01

304

Synthesis of 64Cu-Labeled Magnetic Nanoparticles for Multimodal Imaging  

PubMed Central

Complementary imaging modalities provide more information than either method alone can yield and we have developed a dual-mode imaging probe for combined magnetic resonance (MR) and positron emission tomography (PET) imaging. We have developed dual-mode PET/MRI active probes targeted to vascular inflammation and present synthesis of (1) an aliphatic amine polystyrene bead and (2) a novel superparamagnetic iron oxide nanoparticle targeted to macrophages that were both coupled to positron-emitting copper-64 isotopes. The amine groups of the polystyrene beads were directly conjugated with an amine-reactive form (isothiocyanate) of aza-macrocycle 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA). Iron oxide nanoparticles are dextran sulfate coated, and the surface was modified to contain aldehyde groups to conjugate to an amine-activated DOTA. Incorporation of chelated Cu-64 to nanoparticles under these conditions, which is routinely used to couple DOTA to macromolecules, was unexpectedly difficult and illustrates that traditional conjugation methods do not always work in a nanoparticle environment. Therefore, we developed new methods to couple Cu-64 to nanoparticles and demonstrate successful labeling to a range of nanoparticle types. We obtained labeling yields of 24% for the amine polystyrene beads and 21% radiolabeling yield for the anionic dextran sulfate iron oxide nanoparticles. The new coupling chemistry can be generalized for attaching chelated metals to other nanoparticle platforms.

Jarrett, Benjamin R.; Gustafsson, Bjorn; Kukis, David L.

2008-01-01

305

Nanoparticle–polymer photovoltaic cells  

Microsoft Academic Search

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

Brian R. Saunders; Michael L. Turner

2008-01-01

306

Cell adhesion and proliferation on polyethylene grafted with Au nanoparticles  

NASA Astrophysics Data System (ADS)

Plasma treatment and subsequent Au nano-particles grafting of polyethylene (PE) lead to changes in surface morphology, roughness and wettability, significantly increasing the attractiveness of the material for cells. The PE samples were exposed to argon plasma. Plasma modified PE was chemically grafted by immersion to biphenyldithiol and consequently into solution of Au nano-particles. Changes in chemical structure of the modified PE were studied using X-ray Photoelectron Spectroscopy (XPS) and electrokinetic analysis (?-potential). The surface wettability of the modified PE samples was examined by measurement of the contact angle by standard goniometry. The surface morphology of the plasma modified PE and that grafted with Au nano-particles was studied by Atomic Force Microscopy (AFM). The modified PE samples were seeded with rat vascular smooth muscle cells (VSMCs) and their adhesion and proliferation were studied. Chemically bounded biphenyldithiol increases the number of the incorporated gold nano-particles and changes sample surface properties. The presence of the biphenyldithiol and the gold nano-particles on the PE surface influences dramatically adhesion and proliferation of VSMCs.

Kasálková, N. Slepi?ková; Slepi?ka, P.; Kolská, Z.; Sajdl, P.; Ba?áková, L.; Rimpelová, S.; Švor?ík, V.

2012-02-01

307

Electrostatic plasmon resonances of metal nanoparticles in stratified geometries  

NASA Astrophysics Data System (ADS)

A theoretical electrostatic approach for determination of plasmon eigenresonances and absorption cross section spectra of arbitrarily shaped metal nanoparticles with cylindrical symmetry in stratified geometries is presented. The method is based on a surface integral equation for the surface polarization charge density. From symmetry considerations and by incorporating all effects of the stratified surrounding into the Green's function we show how the three dimensional analysis can be reduced to a single integral over the polar angle along the surface of the metal nanoparticle. The theoretical scheme is exemplified by analyzing silver nanoparticles shaped as spheres, oblate spheroids, and nanodisks in different surroundings involving silicon. The effect of varying the distance between a silver sphere and a silicon surface on plasmonic eigenvalues and absorption cross section spectra is presented. By flattening silver oblate spheroids and nanodisks embedded in a homogenous silicon surrounding it is shown how the fundamental horizontally polarized plasmon resonance can be shifted into the near infrared wavelength range. Also the effect of varying the thickness of thin silicon films with silver nanoparticles embedded is presented. The results indicate that silver nanoparticles embedded in silicon could be interesting for plasmon assisted solar cells.

Jung, Jesper; Pedersen, Thomas G.; Søndergaard, Thomas; Pedersen, Kjeld

2010-08-01

308

Modeling of Au Nanoparticles and Semiconductor Nanowires for Nanodevice Applications  

NASA Astrophysics Data System (ADS)

Semiconductor nanowires with and without plasmon enhancement are being studied for nanodevice applications ranging from chemical sensors to medical monitors and photovoltaics. Semiconductor nanowires can incorporate materials with different bandgaps and can be p- or n-doped. Growths come in different morphologies and geometries (bare, axial or radial heterostructures); all of which expands the design parameters for photocurrent based devices. When Au nanoparticles are attached to nanowires, the local electric field can be enhanced by orders of magnitude, thus increasing their absorption and photocurrent. Using an FDTD Maxwell solver, we simulate local electric fields and absorption characteristics of semiconductor nanowires and Au nanoparticles. We report on spherical, cylindrical and bipyramidal Au nanoparticles with local electric field enhancements that increase with nanoparticle asymmetry and sharp features. The Au nanoparticle modeling data is also in good agreement with experimental absorption data. Initial investigations of 275 nm InP nanowires exhibit internal mode structure under illumination with both polarizations, and absorption coefficients as a function of wavelength. These results provide insight into our experimental investigations of nanowire device applications.

Makepeace, A.; Yarrison-Rice, J. M.; Kumar, P.; Fickenscher, M.; Smith, L. M.; Jackson, H. E.; Choi, Y.-J.; Park, G.-J.; Jagadish, C.

2013-03-01

309

Luminescent Gold Nanoparticles with pH Dependent Membrane Adsorption  

PubMed Central

pH regulates many cellular processes and is also an indicator of disease progression. Therefore, pH responsive materials often serve as either tools in the fundamental understanding of cell biology or medicines for disease diagnosis and therapy. While gold nanoparticles have found broad biomedical applications, very few of them exhibit pH dependent interactions with live cells in a native biological environment due to nonspecific serum protein adsorption. Herein, we report that by coating luminescent gold nanoparticles with a natural peptide, glutathione and the simplest stable aminothiol, cysteamine, we enabled the nanoparticles to exhibit not only high resistance to serum protein adsorption but also pH dependent adsorption onto the live cell membrane in the presence of serum proteins. Incorporating this pH dependent membrane adsorption behavior into gold nanoparticles could potentially catalyze new biomedical applications of metal nanoparticles in the fundamental understanding of biological processes as well as disease diagnosis and therapy, where pH changes are involved.

Yu, Mengxiao; Zhou, Chen; Liu, Jinbin; Hankins, Julia D.; Zheng, Jie

2011-01-01

310

Behavior of metal oxide nanoparticles in natural aqueous matrices  

NASA Astrophysics Data System (ADS)

The increasing use of nanomaterials in consumer products that are exposed to environmental media has led to a need to understand their fate and transport. In particular, metal oxide (MeO) nanoparticles, such as TiO2, ZnO and CeO2, are increasingly incorporated into a wide range of products, from sunscreens to paints and other coatings, and catalysts. With regard to their transport, it is important to determine how far these nanoparticles will travel in different ambient waters, such as rivers, lakes and seawater. There have been a number of studies that have addressed the aggregation of different nanoparticles in simpler aqueous solutions. However, it is important to understand the combined effect of pH, ionic strength, ionic composition, NOM and other characteristics of the aqueous media in which the nanoparticles will be dispersed, which may result in either aggregation and settling, or stabilization and transport. This also affects the bioavailability of the nanomaterials, and the phase (water column or sediments) in which the bulk of the particles are likely to reside. For this study we considered several natural aqueous matrices, including seawater, freshwater, groundwater, rainwater and treated wastewater, as well as two different water matrices used in micro- and mesocosm studies of nanoparticle toxicity. We determined that the two most important water quality characteristics controlling the rate of aggregation, relatively independent of particle composition, are [NOM] and ionic strength.

Keller, A. A.; Zhou, D.; Wang, H.

2009-12-01

311

Covalent assembly of gold nanoparticles: an application toward transistor memory.  

PubMed

This work reports a versatile approach utilizing covalent assembly of functionalized gold nanoparticles for organic field-effect transistor (OFET) based memory devices. 11-Mercapto-1-undecanol functionalized gold nanoparticles (AuNPs) having size of 5 ± 0.5 nm were synthesized and immobilized onto SiO(2) substrate through covalent binding using a functionalized polymer as a surface modifier. The pentacene OFET-based memory devices utilizing such covalently bound gold nanoparticles with nanoparticle density of 5 × 10(11) cm(-2) exhibited a large memory window (7.7 V), high on/off ratio between memory states (10(5)), and long retention time (>10,000 s). The present synthetic route for memory devices incorporating covalently immobilized gold nanoparticles has several advantages such as solution processable, enhanced device stability, low-cost, and low-temperature process and will be a step toward realization for low-cost, lightweight, flexible, logic display driver, and flash memory applications. PMID:22816559

Gupta, Raju Kumar; Ying, Gao; Srinivasan, M P; Lee, Pooi See

2012-08-02

312

Nanoparticles laden in situ gel for sustained ocular drug delivery  

PubMed Central

Proper availability of drug on to corneal surface is a challenging task. However, due to ocular physiological barriers, conventional eye drops display poor ocular bioavailability of drugs (< 1%). To improve precorneal residence time and ocular penetration, earlier our group developed and evaluated in situ gel and nanoparticles for ocular delivery. In interest to evaluate the combined effect of in situ gel and nanoparticles on ocular retention, we combined them. We are the first to term this combination as “nanoparticle laden in situ gel”, that is, poly lactic co glycolic acid nanoparticle incorporated in chitosan in situ gel for sparfloxacin ophthalmic delivery. The formulation was tested for various physicochemical properties. It showed gelation pH near pH 7.2. The observation of acquired gamma camera images showed good retention over the entire precorneal area for sparfloxacin nanoparticle laden in situ gel (SNG) as compared to marketed formulation. SNG formulation cleared at a very slow rate and remained at corneal surface for longer duration as no radioactivity was observed in systemic circulation. The developed formulation was found to be better in combination and can go up to the clinical evaluation and application.

Gupta, Himanshu; Aqil, Mohammed; Khar, Roop K.; Ali, Asgar; Bhatnagar, Aseem; Mittal, Gaurav

2013-01-01

313

Synthesis of Multifunctional Nanoparticles for Cancer Diagnostics and Therapeutics  

NASA Astrophysics Data System (ADS)

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.

Fang, Chen

314

Incorporation in Danish: Implications for interfaces  

Microsoft Academic Search

Syntactic noun incorporation (SNI) in Danish is a phenomenon that has re exes in phonology, syntax, semantics and pragmatics. In contrast with morphological noun incorporation, which involves compounding of an N stem and a V stem to yield a larger, derived V stem (Mithun, 1984, 847), SNI does not involve any overt word order perturbation or overt morphology, but is

Ash Asudeh; Line Hove Mikkelsen

315

Optimal power flow incorporating voltage collapse constraints  

Microsoft Academic Search

The paper presents applications of optimization techniques to voltage collapse studies. First a “maximum distance to voltage collapse” algorithm that incorporates constraints on the current operating conditions is presented. Second, an optimal power flow formulation that incorporates voltage-stability criteria is proposed. The algorithms are tested on a 30-bus system using a standard power flow model, where the effect of limits

William Rosehart; C. Canizares; Victor Quintana

1999-01-01

316

Biodegradable Thermoplastic Polyurethanes Incorporating Polyhedral Oligosilsesquioxane  

Microsoft Academic Search

A new hybrid thermoplastic polyurethane (TPU) system that incorporates an organic, biodegradable poly(D,L- lactide) soft block with a hard block bearing the inorganic polyhedral oligosilsesquioxane (POSS) moiety is introduced and studied. Changes in the polyol composition made through variation of the hydrophilic initiator molecular weight show direct control of the final transition temperatures. Incorporating POSS into the hard segments allows

Pamela T. Knight; Kyung Min Lee; Haihu Qin; Patrick T. Mather

2008-01-01

317

Incorporation and distribution of strontium in bone  

Microsoft Academic Search

The distribution and incorporation of strontium into bone has been examined in rats, monkeys, and humans after oral administration of strontium (either strontium chloride or strontium ranelate). After repeated administration for a sufficient period of time (at least 4 weeks in rats), strontium incorporation into bone reaches a plateau level. This plateau appears to be lower in females than in

S. G Dahl; P Allain; P. J Marie; Y Mauras; G Boivin; P Ammann; Y Tsouderos; P. D Delmas; C Christiansen

2001-01-01

318

Paper surfaces functionalized by nanoparticles  

Microsoft Academic Search

Nanomaterials with unique electronic, optical and catalytic properties have recently been at the forefront of research due to their tremendous range of applications. Taking gold, silver and titania nanoparticles as examples, we have reviewed the current research works on paper functionalized by these nanoparticles. The functionalization of paper with only a very small concentration of nanoparticles is able to produce

Ying Hui Ngo; Dan Li; George P. Simon; Gil Garnier

2011-01-01

319

Paper surfaces functionalized by nanoparticles.  

PubMed

Nanomaterials with unique electronic, optical and catalytic properties have recently been at the forefront of research due to their tremendous range of applications. Taking gold, silver and titania nanoparticles as examples, we have reviewed the current research works on paper functionalized by these nanoparticles. The functionalization of paper with only a very small concentration of nanoparticles is able to produce devices with excellent photocatalytic, antibacterial, anti-counterfeiting, Surface Enhanced Raman Scattering (SERS) and Surface Plasmon Resonance (SPR) performances. This review presents a brief overview of the properties of gold, silver and titania nanoparticles which contribute to the major applications of nanoparticles-functionalized paper. Different preparation methods of the nanoparticles-functionalized paper are reviewed, focusing on their ability to control the morphology and structure of paper as well as the spatial location and adsorption state of nanoparticles which are critical in achieving their optimum applications. In addition, main applications of the nanoparticles-functionalized papers are highlighted and their critical challenges are discussed, followed by perspectives on the future direction in this research field. Whilst a few studies to date have characterized the distribution of nanoparticles on paper substrates, none have yet optimized paper as a nanoparticles' substrate. There remains a strong need to improve understanding on the optimum adsorption state of nanoparticles on paper and the heterogeneity effects of paper on the properties of these nanoparticles. PMID:21324427

Ngo, Ying Hui; Li, Dan; Simon, George P; Garnier, Gil

2011-01-22

320

Lactobacillusassisted synthesis of titanium nanoparticles  

PubMed Central

An eco-friendlylactobacillussp. (microbe) assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

2007-01-01

321

Gold Nanoparticles Cytotoxicity  

NASA Astrophysics Data System (ADS)

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.

Mironava, Tatsiana

322

Engineered Nanoparticles and Their Identification Among Natural Nanoparticles  

NASA Astrophysics Data System (ADS)

The more nanotechnology develops, the more likely the release of engineered nanoparticles into the environment becomes. Due to a huge excess of natural nanoparticles, the identification and quantification of engineered nanoparticles pose a big challenge to analysts. Moreover, identification in a qualitative sense and quantification by mass concentration alone are not sufficient, because the potential environmental hazard arising from engineered nanoparticles is controlled by many other properties of the particles. We discuss the most important methods of fractionation and detection of both natural and engineered nanoparticles, with a focus on the chemical nature of the particles, particle concentration, and particle size. Analyses should not rely on only one method; instead, several complementary methods should, if possible, be used. Coupled techniques should be further developed and increasingly applied. Dedicated techniques that are tailored to the search for a particular sort of engineered nanoparticles are more promising than universal approaches that search for any engineered nanoparticles.

Zänker, H.; Schierz, A.

2012-07-01

323

Engineered nanoparticles and their identification among natural nanoparticles.  

PubMed

The more nanotechnology develops, the more likely the release of engineered nanoparticles into the environment becomes. Due to a huge excess of natural nanoparticles, the identification and quantification of engineered nanoparticles pose a big challenge to analysts. Moreover, identification in a qualitative sense and quantification by mass concentration alone are not sufficient, because the potential environmental hazard arising from engineered nanoparticles is controlled by many other properties of the particles. We discuss the most important methods of fractionation and detection of both natural and engineered nanoparticles, with a focus on the chemical nature of the particles, particle concentration, and particle size. Analyses should not rely on only one method; instead, several complementary methods should, if possible, be used. Coupled techniques should be further developed and increasingly applied. Dedicated techniques that are tailored to the search for a particular sort of engineered nanoparticles are more promising than universal approaches that search for any engineered nanoparticles. PMID:22482788

Zänker, H; Schierz, A

2012-04-15

324

Semiconducting nanoparticles with surface modification  

US Patent & Trademark Office Database

The invention relates to semiconducting nanoparticles. The nanoparticles of the invention comprise a single element or a compound of elements in one or more of groups II, III, IV, V, VI. The nanoparticles have a size in the range of 1 nm to 500 nm, and comprise from 0.1 to 20 atomic percent of oxygen or hydrogen. The nanoparticles are typically formed by comminution of bulk high purity silicon. One application of the nanoparticles is in the preparation of inks which can be used to define active layers or structures of semiconductor devices by simple printing methods.

Britton; David Thomas (Cape Town, ZA); Harting; Margit (Cape Town, ZA)

2013-01-15

325

Magnetic Dipolar Interactions in Nanoparticle Systems: Theory, Simulations and Ferromagnetic Resonance  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticle assemblies present novel magnetic properties with respect to their bulk constituent components. In addition to the surface effects produced by the modified atomic symmetry in such low dimensional systems, the magnetic coupling between the particles also plays a significant role in determining the overall magnetic behavior of a magnetic nanoparticle assembly. In this Chapter, we describe a theoretical model that accounts for the dipolar magnetic interaction between particles. There are two fundamental aspects of interest in our studies: the spatial distribution of the particles and density of the particle. These aspects have been addressed in our simulations, where we have performed simulations for regular and random arrays of particles. We will discuss the general theory of ferromagnetic resonance (FMR) applied to such systems and how the specific dipolar interactions can be incorporated for nanoparticle systems. The spatial distribution of particles can give valuable information of the strength of the dipolar interaction between them and we will demonstrate how this can be used in real systems. We have performed FMR experiments on nanoparticle assemblies of ? - Fe2O3 nanoparticles with different average particle sizes (2.7-7.3 nm) and particle densities, where samples are in rectangular slab shape. Measurements were performed as a function of the angle between the sample plane and applied magnetic field. Recent studies have shown that the incorporation of the dipolar interactions into FMR theory can explain the experimental results for angular studies in magnetic nanoparticle assemblies [1].

Schmool, D. S.; Schmalzl, M.

326

Sensitization of fluorescence of dye molecules in nanoparticles of metal complexes  

NASA Astrophysics Data System (ADS)

We studied the dependence of absorption and fluorescence spectra of complexes of Al, In, Sc, Y, and La with dibenzoylmethane and naphthoyltrifluoroacetone, as well as the dependence of sensitized fluorescence of dyes in nanoparticles of these complexes, in relation to the water pH, the ratio between ions and diketones, and the ion selection. We showed that the ability of complexes of ions to form nanoparticles that efficiently sensitize dye molecules incorporated into them is determined by stability constants of these ions with organic ligands and by their ability to compete with the formation of hydroxy complexes of these ions. We found that nanoparticles consist of diketonates of different compositions and that Nile red incorporated into nanoparticles is an indicator of the dependence of the composition of nanoparticles on the selection of the central ion of complexes and conditions of their formation. We revealed that complexes M(diketone)(OH)2 self-assemble into nanoparticles with an admixture of dye molecules and efficiently sensitize dyes upon excitation into absorption bands of complexes. We showed that, at concentrations of rhodamine 6G in water smaller than 50 nM, the use of a solution that contains 50 ?M of Al(III), In(III), or Sc(III) + 50 ?M of naphthoyltrifluoroacetone makes it possible to increase the sensitivity of the luminescence analysis by 20-fold for the presence of rhodamine 6G in an aqueous solution.

Dudar', S. S.; Sveshnikova, E. B.; Ermolaev, V. L.

2010-10-01

327

TOPICAL REVIEW: Biopolymeric nanoparticles  

NASA Astrophysics Data System (ADS)

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.

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

2010-02-01

328

Nanoparticle-Based Biosensors and Bioassays  

SciTech Connect

In this book chapter, we review the recent advances in nanoparticles based bioassay. The nanoparticles include quantum dots, silica nanoparticles and apoferritin nanoparticles. The new nanoparticles-based labels hold great promise for multiplex protein and DNA detection and for enhancing the sensitivity of other bioassays.

Liu, Guodong; Wang, Jun; Lin, Yuehe; Wang, Joseph

2007-10-11

329

Optimal Design of Structures Incorporating 'Smart Materials'.  

National Technical Information Service (NTIS)

The purpose of this project was to develop a rigorous theoretical foundation of the design of structures incorporating general 'smart' materials, and to explore, extend and develop the use of sensors and actuators that employ 'finite length' paths. It is ...

P. D. Washabaugh J. E. Taylor A. M. Waas

1998-01-01

330

49 CFR 572.180 - Incorporated materials.  

Code of Federal Regulations, 2011 CFR

...with Rib Extensions; (viii) Drawing No. 175-5000, Abdominal Assembly; (ix) Drawing No. 175-5500 Lumbar Spine Assembly...181 and 572.185; (viii) Drawing No. 175-5000, Abdominal Assembly, incorporated by...

2011-10-01

331

49 CFR 572.180 - Incorporated materials.  

Code of Federal Regulations, 2012 CFR

...and 572.185; (vii) Drawing No. 175-4000, Thorax Assembly...181 and 572.185; (viii) Drawing No. 175-5000, Abdominal Assembly, incorporated by reference...181 and 572.186; (ix) Drawing No. 175-5500, Lumbar...

2012-10-01

332

Concept Sciences, Incorporated, Hanover Township, Pennsylvania.  

National Technical Information Service (NTIS)

On Friday, February 19, 1999, a devastating explosion destroyed a plant operated by Concept Sciences, Incorporated (CSI) in Hanover Township, Pennsylvania. The blast killed five people and caused approximately $5 million in damages. Fourteen people, inclu...

J. L. Cook

1999-01-01

333

Broadband Conventional Beamforming Incorporating Adaptive Equalization.  

National Technical Information Service (NTIS)

This report discusses methods which attempt to coherently recombine the spatially and temporally different multipaths with the direct path to enhance array gain. These methods are based on utilizing a broadband conventional beamformer incorporating adapti...

R. C. North

1992-01-01

334

49 CFR 572.80 - Incorporated materials.  

Code of Federal Regulations, 2011 CFR

...DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES 9-Month Old Child § 572.80 Incorporated materials. The drawings and specifications referred to in § 572.81(a) that are not set forth in full are hereby...

2011-10-01

335

High luminescence, organic–inorganic nanocomposite films with covalently linked 8-hydroxyquinoline anchored to ZnS nanoparticles  

Microsoft Academic Search

A series of transparent, highly fluorescent, organic–inorganic nanocomposite films were prepared by incorporating mercaptoethanol-capped ZnS nanoparticles into a copolymer of trialkoxysilane-capped poly(MMA-co-Hq-CH2-HEMA) carrying an 8-hydroxyquinoline (Hq) unit, followed by ligand exchange and sol–gel processing. Electron microscopy revelaed that the ZnS nanoparticles were uniformly dispersed in the organic–inorganic hybrid matrix regardless of the content and matrix composition. The hybrid nanocomposites had

Yongli Shi; Yuqin Fu; Changli Lü; Li Hui; Zhongmin Su

2010-01-01

336

Chelating agent assisted microwave synthesis of carbon supported Pt nanoparticles for low temperature polymer electrolyte fuel cells  

Microsoft Academic Search

Colloidal suspensions of almost spherical crystalline Pt nanoparticles with a narrow size distribution were synthesized using a microwave synthesis process. Pt(phen)22+ complex (phen=1,10-phenanthroline, C12H10N2) was used as a precursor which was incorporated onto commercial Vulcan XC-72 carbon powder. X-ray diffraction and transmission electron microscopy were used to characterize the Pt\\/C catalysts. It was found that the Pt nanoparticles were uniform

Shyh-Jiun Liu; Chia-Hung Huang; Chun-Kai Huang; Weng-Sing Hwang

2009-01-01

337

Preparation and Characterization of a Novel Drug Delivery System: Biodegradable Nanoparticles in Thermosensitive Chitosan\\/Gelatin Blend Hydrogels  

Microsoft Academic Search

A novel injectable in situ gelling drug delivery system (DDS) consisting of biodegradable N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) nanoparticles and thermosensitive chitosan\\/gelatin blend hydrogels was developed for prolonged and sustained controlled drug release. Four different HTCC nanoparticles, prepared based on ionic process of HTCC and oppositely charged molecules such as sodium tripolyphosphate, sodium alginate and carboxymethyl chitosan, were incorporated

Yuhua Chang; Ling Xiao

2010-01-01

338

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

PubMed

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

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

2013-08-19

339

Synthetic Polymer Nanoparticles with Antibody-Like Affinity for a Hydrophilic Peptide  

PubMed Central

Synthetic polymer nanoparticles with antibody-like affinity for a hydrophilic peptide have been prepared by inverse microemulsion polymerization. Peptide affinity was achieved in part by incorporating the target (imprint) peptide in the polymerization reaction mixture. Incorporation of the imprint peptide assists in the creation of complementary binding sites in the resulting polymer nanoparticle (NP). To orient the imprint peptide at the interface of the water and oil domains during polymerization, the peptide target was coupled with fatty acid chains of varying length. The peptide-NP binding affinities (90 nM~900 nM) were quantitatively evaluated by a quartz crystal microbalance (QCM). The optimal chain length was established that created high affinity peptide binding sites on the surface of the nanoparticles. This method can be used for the preparation of nanosized synthetic polymers with antibody-like affinity for hydrophilic peptides and proteins (“plastic antibodies”).

Zeng, Zhiyang; Hoshino, Yu; Rodriguez, Andy; Yoo, Hoseong; Shea, Kenneth J.

2009-01-01

340

Polymerization of butadiene on nanoparticles’ surfaces and formation of metal\\/polymer nanocomposites  

Microsoft Academic Search

In this paper, we demonstrate that laser vaporization of metals in the presence of a small concentration of butadiene vapor leads to the polymerization of butadiene and incorporation of the metal nanoparticles within the polymer matrix. The metal nanocomposites are characterized by electron microscopy, X-ray diffraction and EDX. The results from high pressure mass spectrometry indicate that multiple additions of

V. Abdelsayed; Y. Ibrahim; M. S. El-Shall; S. Deevi

2006-01-01

341

Gene expression analysis in rat lungs after intratracheal exposure to nanoparticles doped with cadmium  

Microsoft Academic Search

Silica nanoparticles (NPs) incorporating cadmium (Cd) have been developed for a range of potential application including drug delivery devices. Occupational Cd inhalation has been associated with emphysema, pulmonary fibrosis and lung tumours. Mechanistically, Cd can induce oxidative stress and mediate cell-signalling pathways that are involved in inflammation.This in vivo study aimed at investigating pulmonary molecular effects of NPs doped with

Teresa Coccini; Marco Fabbri; Elisa Roda; Maria Grazia Sacco; Luigi Manzo; Laura Gribaldo

2011-01-01

342

Side chain and backbone structure-dependent subcellular localization and toxicity of conjugated polymer nanoparticles.  

PubMed

The subcellular localization and toxicity of conjugated polymer nanoparticles (CPNs) are dependent on the chemical structure of the side chains and backbone. Primary amine-containing CPNs exhibit high Golgi localization with no toxicity. Incorporation of short ethylene oxide and tertiary amine side chains contributes to decreased Golgi localization and increased toxicity, respectively. PMID:23722239

Mendez, Eladio; Moon, Joong Ho

2013-07-11

343

Preparation and optical properties of barium titanate thin films dispersed with Au nanoparticles  

Microsoft Academic Search

A high doping level of Au nanoparticles was successfully incorporated into sol-gel derived dip-coating amorphous BaTiO3 thin films. Unique absorption red shift was observed by absorption spectra. The calculated values of third nonlinear susceptibility ?(3) varied between 10?8 and 10?9 esu.

Yong Yang; Jianlin Shi; Weiming Huang; Shugang Dai; Lin Wang

2002-01-01

344

Enhanced gas separation performance of nanocomposite membranes using MgO nanoparticles  

Microsoft Academic Search

Gas separation membranes with enhanced performance were developed by the introduction of nanosized magnesium oxide particles followed by treatment with silver ions. Firstly, nanocomposite membranes were fabricated by incorporating nanoscale magnesium oxide particles with different loadings into the Matrimid matrix. The addition of MgO nanoparticles led to an increase in gas permeability of membranes; the highest permeability was observed for

Seyed Saeid Hosseini; Yi Li; Tai-Shung Chung; Ye Liu

2007-01-01

345

Anti-Inflammatory Effects of Flavonoids: Genistein, Kaempferol, Quercetin, and Daidzein Inhibit STAT-1 and NF-?B Activations, Whereas Flavone, Isorhamnetin, Naringenin, and Pelargonidin Inhibit only NF-?B Activation along with Their Inhibitory Effect on iNOS Expression and NO Production in Activated Macrophages  

PubMed Central

In inflammation, bacterial products and proinflammatory cytokines induce the formation of large amounts of nitric oxide (NO) by inducible nitric oxide synthase (iNOS), and compounds that inhibit NO production have anti-inflammatory effects. In the present study, we systematically investigated the effects of 36 naturally occurring flavonoids and related compounds on NO production in macrophages exposed to an inflammatory stimulus (lipopolysaccharide, LPS), and evaluated the mechanisms of action of the effective compounds. Flavone, the isoflavones daidzein and genistein, the flavonols isorhamnetin, kaempferol and quercetin, the flavanone naringenin, and the anthocyanin pelargonidin inhibited iNOS protein and mRNA expression and also NO production in a dose-dependent manner. All eight active compounds inhibited the activation of nuclear factor-?B (NF-?B), which is a significant transcription factor for iNOS. Genistein, kaempferol, quercetin, and daidzein also inhibited the activation of the signal transducer and activator of transcription 1 (STAT-1), another important transcription factor for iNOS. The present study characterises the effects and mechanisms of naturally occurring phenolic compounds on iNOS expression and NO production in activated macrophages. The results partially explain the pharmacological efficacy of flavonoids as anti-inflammatory compounds.

Hamalainen, Mari; Nieminen, Riina; Vuorela, Pia; Heinonen, Marina; Moilanen, Eeva

2007-01-01

346

Dextran-b-poly(L-histidine) copolymer nanoparticles for ph-responsive drug delivery to tumor cells  

PubMed Central

Purpose Nanoparticles based on stimuli-sensitive drug delivery have been extensively investigated for tumor targeting. Among them, pH-responsive drug targeting using pH-sensitive polymers has attracted attention because solid tumors have an acidic environment. A dextran-b-poly(L-histidine) (DexPHS) copolymer was synthesized and pH-responsive nanoparticles were fabricated for drug targeting. Methods and results A DexPHS block copolymer was synthesized by attaching the reductive end of dextran to the amine groups of poly(L-histidine). pH-responsive nanoparticles incorporating doxorubicin were fabricated and studied in HuCC-T1 cholangiocarcinoma cells. Synthesis of DexPHS was confirmed by 1H nuclear magnetic resonance spectroscopy, with specific peaks of dextran and PHS observed at 2–5 ppm and 7.4–9.0 ppm, respectively. DexPHS nanoparticles showed changes in particle size with pH sensitivity, ie, the size of the nanoparticles increased at an acidic pH and decreased at a basic pH. DexPHS block copolymer nanoparticles incorporating doxorubicin were prepared using the nanoprecipitation dialysis method. The doxorubicin release rate was increased at acidic pH compared with basic pH, indicating that DexPHS nanoparticles have pH-sensitive properties and that drug release can be controlled by variations in pH. The antitumor activity of DexPHS nanoparticles incorporating doxorubicin were studied using HuCC-T1 cholangiocarcinoma cells. Viability was decreased in cells treated with nanoparticles at acidic pH, whereas cell viability in response to treatment with doxorubicin did not vary according to changes of pH. Conclusion Our results indicated that DexPHS polymeric micelles are promising candidates for antitumor drug targeting.

Hwang, Jong-ho; Choi, Cheol Woong; Kim, Hyung-Wook; Kim, Do Hyung; Kwak, Tae Won; Lee, Hye Myeong; Kim, Cy hyun; Chung, Chung Wook; Jeong, Young-II; Kang, Dae Hwan

2013-01-01

347

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

PubMed Central

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.

2012-01-01

348

Modulation of residual stress in diamond like carbon films with incorporation of nanocrystalline gold  

NASA Astrophysics Data System (ADS)

Residual stress modulation in the diamond-like carbon coatings with incorporation of gold nanoparticles was studied critically. The films were deposited on glass and Si (1 0 0) substrates by using capacitatively coupled plasma chemical vapor deposition. Stresses in the films were determined from the broadening of the optical absorption tail and were found to decrease from 2.3 GPa to 0.48 GPa with increasing gold content (2-7 at.% Au) in the DLC matrix. Gold incorporation also made the films harder than the corresponding DLC coatings. Modulation of stress with nanocrystalline gold content in the DLC matrix was related to the relative amount of sp2/sp3 content in the DLC films.

Paul, R.; Bhattacharyya, S. R.; Bhar, R.; Pal, A. K.

2011-10-01

349

Synthesis, characterization and computational study of nitrogen-doped CeO2 nanoparticles with visible-light activity.  

PubMed

Nitrogen-doped CeO2 nanoparticles were synthesized through a wet-chemical route. Nitrogen has been successfully incorporated into CeO2 nanoparticles and the nitrogen-doping level was also successfully controlled. The optical properties due to the different N-doping levels in CeO2 nanoparticles were characterized by UV-Vis diffuse reflectance spectroscopy (DRS), which showed a visible-light absorbance shift. The resulting nanoparticles show enhanced visible-light sensitivity and photocatalytic activity compared to undoped CeO2 nanoparticles. DFT calculations were performed to explore the effect of nitrogen doping versus oxygen vacancies. The calculations show that the change of the electronic structure upon N-doping CeO2 is quite different from that of N-doped TiO2, which has been studied extensively. PMID:18956099

Mao, Changjie; Zhao, Yixin; Qiu, Xiaofeng; Zhu, Junjie; Burda, Clemens

2008-07-30

350

Conduction electron resonance used to determine size of palladium nanoparticles in proton conducting ceramics  

NASA Astrophysics Data System (ADS)

A technique for determining the size of metallic nanoparticles incorporated into a ceramic is demonstrated using conduction electron paramagnetic resonance (CEPR). The resonances associated with palladium nanoparticles in a perovskite material are identified and studied as a function of temperature. As this line shape changes with temperature, the point at which the skin depth of the palladium is the same as the size of the nanoparticles is clearly identified due to a microwave saturation effect. This allows for a determination of their average size, which, in this case is 75 ± 20 nm. This is the first example of CEPR being used to determine metallic nanoparticle size in a technologically relevant, embedded in a non EPR-inert material system.

Simonds, Brian J.; Subramaniyan, Archana; O'Hayre, Ryan; Craig Taylor, P.

2012-12-01

351

Conduction electron resonance used to determine size of palladium nanoparticles in proton conducting ceramics.  

PubMed

A technique for determining the size of metallic nanoparticles incorporated into a ceramic is demonstrated using conduction electron paramagnetic resonance (CEPR). The resonances associated with palladium nanoparticles in a perovskite material are identified and studied as a function of temperature. As this line shape changes with temperature, the point at which the skin depth of the palladium is the same as the size of the nanoparticles is clearly identified due to a microwave saturation effect. This allows for a determination of their average size, which, in this case is 75±20nm. This is the first example of CEPR being used to determine metallic nanoparticle size in a technologically relevant, embedded in a non EPR-inert material system. PMID:23143009

Simonds, Brian J; Subramaniyan, Archana; O'Hayre, Ryan; Taylor, P Craig

2012-10-24

352

Synthesis of monodisperse, hierarchically mesoporous, silica microspheres embedded with magnetic nanoparticles.  

PubMed

We report a preparation method for the synthesis of monodisperse magnetic polymer/silica hybrid microspheres using polymer microspheres incorporated with magnetic nanoparticles as a novel template. Monodisperse, hierarchically mesoporous, silica microspheres embedded with magnetic nanoparticles were successfully fabricated after the calcination of the hybrid microspheres. The magnetic nanoparticles were encapsulated in silica and distributed over the whole area of the porous microspheres without leakage. The resulting inorganic materials possess highly useful properties such as high magnetic nanoparticle loading, high surface area, and large pore volumes. The hierarchically mesoporous magnetic silica microspheres resulted in a high bovine serum albumin (BSA) protein adsorption capacity (260 mg/g) and a fast adsorption rate (reaching equilibrium with 8 h). PMID:22540143

Wang, Yong; He, Jie; Chen, Jiwei; Ren, Lianbing; Jiang, Biwang; Zhao, Jing

2012-05-03

353

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

SciTech Connect

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.

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

2006-05-17

354

LDRD Progress Report: Radioimmunotherapy using oxide nanoparticles: Radionuclide contaiment and mitigation of normal tissue toxicity.  

SciTech Connect

Radionuclides with specific emission properties can be incorporated into metal-chalcogenide and metal-oxide nanoparticles. Coupled to antibodies, these conjugates could be injected into the bloodstream to target and destroy non-solid tumors or target organs for radioimaging. In the first year of this project, two types of radioactive nanoparticles, CdTe: {sup 125m}Te and Y{sub 2}O{sub 3}: {sup 170}Tm were synthesized and coupled to antibodies specific to murine epithelial lung tissue. The nanoparticles successfully target the lung tissue in vivo. Some leaching of the radioisotope was observed. The coming year will explore other types of nanoparticles (other crystal chemistries) in order to minimize leaching.

Rondinone, Adam Justin [ORNL; Dai, Sheng [ORNL; Mirzadeh, Saed [ORNL; Kennel, Steve J [ORNL

2005-10-01

355

Magnetic and fluorescent multifunctional chitosan nanoparticles as a smart drug delivery system  

NASA Astrophysics Data System (ADS)

An innovative drug delivery system based on magnetic and fluorescent multifunctional chitosan nanoparticles was developed, which combined magnetic targeting, fluorescent imaging and stimulus-responsive drug release properties into one drug delivery system. Water-soluble superparamagnetic Fe3O4 nanoparticles, CdTe quantum dots (QDs) and pharmaceutical drugs were simultaneously incorporated into chitosan nanoparticles; cross-linking the composite particles with glutaraldehyde tailored their size, morphology, surface properties and drug release behaviors. The system showed superparamagnetic and strong fluorescent properties, and was used as a controlled drug release vehicle, which showed pH-sensitive drug release over a long time. The composite magnetic and fluorescent chitosan nanoparticles are potential candidates as a smart drug delivery system.

Li, Linlin; Chen, Dong; Zhang, Yanqi; Deng, Zhengtao; Ren, Xiangling; Meng, Xianwei; Tang, Fangqiong; Ren, Jun; Zhang, Lin

2007-10-01

356

Health implications of nanoparticles  

Microsoft Academic Search

Nanoparticles are increasingly used in a wide range of applications in science, technology and medicine. Since they are produced for specific purposes which cannot be met by larger particles and bulk material they are likely to be highly reactive, in particular, with biological systems. On the other hand a large body of know-how in environmental sciences is available from toxicological

Wolfgang G. Kreyling; Manuela Semmler-Behnke; Winfried Möller

2006-01-01

357

Adhesion between nanoparticles  

Microsoft Academic Search

A study of the contact and adhesion between panicles with clean surfaces (free from oxide and other contamination) is important but increasingly more difficult to perform as the particle size is reduced to a nanoscale. A reproducible way of finding such contacts between a large number of nanoparticles has been developed. Cobalt particles within the size range 5–200 nm have

Y. Yao; A. R. Thölén

1999-01-01

358

Magnetic nanoparticles for theragnostics  

Microsoft Academic Search

Engineered magnetic nanoparticles (MNPs) represent a cutting-edge tool in medicine because they can be simultaneously functionalized and guided by a magnetic field. Use of MNPs has advanced magnetic resonance imaging (MRI), guided drug and gene delivery, magnetic hyperthermia cancer therapy, tissue engineering, cell tracking and bioseparation. Integrative therapeutic and diagnostic (i.e., theragnostic) applications have emerged with MNP use, such as

Veronica I. Shubayev; Thomas R. Pisanic II; Sungho Jin

2009-01-01

359

Nanoparticles in forensic science  

NASA Astrophysics Data System (ADS)

Nanoparticles appear in several areas of forensic science including security documents, paints, inks, and reagents that develop latent prints. One reagent (known as the silver physical developer) that visualizes the water insoluble components of latent print residue is based on the formation of highly charged silver nanoparticles. These attach to and grow on the residue and generate a silver image. Another such reagent involves highly charged gold nanoparticles. These attach to the residue forming a weak gold image which can be amplified with a silver physical developer. Nanoparaticles are also used in items such as paints, printing inks, and writing inks. Paints and most printing inks consist of nano-sized pigments in a vehicle. However, certain modern ink jet printing inks now contain nano-sized pigments to improve their light fastness and most gel inks are also based on nano scale pigments. These nanoparticlecontaining materials often appear as evidence and are thus subject to forensic characterization. Both luminescent (quantum dots), up-converting nano scale phosphors, and non luminescent nanoparticles are used as security tags to label product, add security to documents, and as anti counterfeiting measures. These assist in determining if an item is fraudulently made.

Cantu, Antonio A.

2008-10-01

360

Nanoparticle assemblies as memristors.  

PubMed

Recently a memristor ( Chua, L. O. IEEE Trans. Circuit Theory 1971 , 18 , 507 ), the fourth fundamental passive circuit element, has been demonstrated as thin film device operations ( Strukov, D. B.; Snider, G. S.; Stewart, D. R.; Williams, R. S. Nature (London) 2008 , 453 , 80 ; Yang, J. J.; Pickett. M. D.; Li, X.; Ohlberg, D. A. A.; Stewart, D. R.; Williams, R. S. Nat. Nanotechnol. 2008 , 3 , 429 ). A new addition to the memristor family can be nanoparticle assemblies consisting of an infinite number of monodispersed, crystalline magnetite (Fe(3)O(4)) particles. Assembly of nanoparticles that have sizes below 10 nm, exhibits at room temperature a voltage-current hysteresis with an abrupt and large bipolar resistance switching (R(OFF)/R(ON) approximately 20). Interestingly, observed behavior could be interpreted by adopting an extended memristor model that combines both a time-dependent resistance and a time-dependent capacitance. We also observed that such behavior is not restricted to magnetites; it is a general property of nanoparticle assemblies as it was consistently observed in different types of spinel structured nanoparticles with different sizes and compositions. Further investigation into this new nanoassembly system will be of importance to the realization of the next generation nanodevices with potential advantages of simpler and inexpensive device fabrications. PMID:19408928

Kim, Tae Hee; Jang, Eun Young; Lee, Nyun Jong; Choi, Deung Jang; Lee, Kyung-Jin; Jang, Jung-tak; Choi, Jin-sil; Moon, Seung Ho; Cheon, Jinwoo

2009-06-01

361

Agglomeration of magnetic nanoparticles.  

PubMed

The formation of agglomerates by salt-induced double layer compression of magnetic nanoparticles in the absence and presence of an external magnetic field was investigated experimentally as well as computationally in this study. The structures of the agglomerates were analyzed through scanning electron microscopy and proved to be highly porous and composed of large spaces among the branches of a convoluted network. In the absence of an external magnetic field, the branches of such a network were observed to be oriented in no particular direction. In contrast, when the agglomeration process was allowed to occur in the presence of an external magnetic field, these branches appeared to be oriented predominantly in one direction. A modified Discrete Element Method was applied to simulate the agglomeration process of magnetic nanoparticles both in the absence and presence of an external magnetic field. The simulations show that agglomeration occurred by the formation of random clusters of nanoparticles which then joined to form a network. In the presence of anisotropic magnetic forces, these clusters were rotated to align along the direction of the magnetic field and the final network formed consisted largely of elongated branches of magnetic nanoparticles. PMID:22462837

Lim, Eldin Wee Chuan; Feng, Ruili

2012-03-28

362

Polyoxometalate-decorated nanoparticles.  

PubMed

Polyoxometalate cluster anions (POMs) control formation and morphology, and serve as protecting ligands, for structurally and compositionally diverse nanostructures. While numerous examples of POM-protected metal(0) nanoparticle syntheses and reactions can now be found in the literature, the use of POMs to prepare nano-scale analogs of binary inorganic materials, such as metal-oxides, sulfides and halides, is a relatively recent development. The first part of this critical review summarizes the use of POMs as protecting ligands for metal(0) nanoparticles, as well as their use as templates for the preparation of new inorganic materials. Here, key findings that reveal general trends are given additional emphasis. In the second part of the review, new information concerning the structure of POM-protected metal(0) nanoparticles is systematically developed. This information, obtained by the combined use of cryogenic transmission microscopy (cryo-TEM) and UV-vis spectroscopy, provides a new perspective on the formation and structure of POM-decorated nanoparticles, and on the rational design of catalytic and other functional POM-based nano-assemblies. PMID:22814638

Wang, Yifeng; Weinstock, Ira A

2012-07-20

363

Targeting nanoparticles to cancer  

Microsoft Academic Search

Nanotechnology applications in medicine, termed as nanomedicine, have introduced a number of nanoparticles of variable chemistry and architecture for cancer imaging and treatment. Nanotechnology involves engineering multifunctional devices with dimensions at the nanoscale, similar dimensions as those of large biological vesicles or molecules in our body. These devices typically have features just tens to hundred nanometers across and they can

M. Wang; M. Thanou

2010-01-01

364

Novel pentablock copolymer (PLA-PCL-PEG-PCL-PLA) based nanoparticles for controlled drug delivery: Effect of copolymer compositions on the crystallinity of copolymers and in vitro drug release profile from nanoparticles.  

PubMed

The purpose of this investigation was to design novel pentablock copolymers (polylatide-polycaprolactone-polyethylene glycol- polycaprolactone-polylatide) (PLA-PCL-PEG-PCL-PLA) to prepare nanoparticle formulations which provide continuous delivery of steroids over a longer duration with minimal burst effect. Another purpose was to evaluate the effect of poly (L-lactide) (PLLA) or poly (D, L-lactide) (PDLLA) incorporation on crystallinity of pentablock copolymers and in vitro release profile of triamcinolone acetonide (selected as model drug) from nanoparticles. PLA-PCL-PEG-PCL-PLA copolymers with different block ratio of PCL/PLA segment were synthesized. Release of triamcinolone acetonide from nanoparticles was significantly affected by crystallinity of the copolymers. Burst release of triamcinolone acetonide from nanoparticles was significantly minimized with incorporation of proper ratio of PDLLA in the existing triblock (PCL-PEG-PCL) copolymer. Moreover, pentablock copolymer based nanoparticles exhibited continuous release of triamcinolone acetonide. Pentablock copolymer based nanoparticles can be utilized to achieve continuous near zero-order delivery of corticosteroids from nanoparticles without any burst effect. PMID:23626400

Tamboli, Viral; Mishra, Gyan P; Mitra, Ashim K

2013-05-01

365

Functionalized Fe3O4@Au superparamagnetic nanoparticles: in vitro bioactivity  

NASA Astrophysics Data System (ADS)

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.

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

366

Preparation of ZnO nanoparticles in a reverse micellar system and their photoluminescence properties.  

PubMed

ZnO nanoparticles with spherical morphology and narrow size distribution were obtained by calcination of Zn(OH)2 nanoparticles, which were prepared in a polyethylene glycol mono-4-nonylphenyl ether (NP-5)/cyclohexane reverse micellar system and incorporated into polyurea (PUA) via an in situ polymerization of hexamethylene diisocyanate (HDI). The resulting ZnO nanoparticles demonstrated a near-UV emission and a green emission, the intensity ratio of which depended on calcination conditions. For the nanoparticles studied, the calcination atmosphere influenced remarkably the photoluminescence properties such as intensity ratio of the near-UV emission to green emission, rather than the size, morphology, and crystallinity of the ZnO nanoparticles. The green emission decreased by calcination in O2 flow but increased by calcination in N2 flow, as compared with the case calcined in air flow. This finding suggests that the green emission is enhanced with the increase of the number of oxygen vacancies of the ZnO nanoparticles and thus the photoluminescence properties of the nanoparticles were successfully controlled by the calcination condition, without changing the size and morphology. PMID:15752800

Hirai, Takayuki; Asada, Yoko

2005-04-01

367

Release of adriamycin from poly(gamma-benzyl-L-glutamate)/poly(ethylene oxide) nanoparticles.  

PubMed

Prolonged circulation of anticancer agent in blood is expected to decrease the host toxicity and enhance the anticancer activity. The purpose of this study is to develop and characterize the prolonged and sustained release formulation of anticancer agent using biodegradable poly(gamma-benzyl-L-glutamate)/poly(ethylene oxide) (PBLG/PEO) polymer nanoparticles. PBLG/PEO polymer is a hydrophilic/hydrophobic block copolymer and forms a micelle-like structure in solution. Spherical nanoparticles incorporating adriamycin were prepared by a dialysis method. The fluorescence intensity of adriamycin in the nanoparticles was increased when sodium dodecylsulfate was added. It is one of the evidences of entrapment of adriamycin in the polymer nanoparticles. Only 20% of entrapped drug was released in 24 h at 37 degrees C a and the release was dependent on the molecular weight of hydrophobic polymer. The endothermic peak of adriamycin at 197 degrees C disappeared in the nanoparticles system, suggesting the inhibition of a crystallization of adriamycin by polymer adsorption during the precipitation process. The mean residence time of adriamycin from the nanoparticles was more than threefold that from a free adriamycin. These results suggest usefulness of PBLG/PEO nanoparticles as a sustained and prolonged release carrier for adriamycin. PMID:10370207

Oh, I; Lee, K; Kwon, H Y; Lee, Y B; Shin, S C; Cho, C S; Kim, C K

1999-04-20

368

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

PubMed Central

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.

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

2011-01-01

369

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

PubMed Central

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.

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

2011-01-01

370

Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols.  

PubMed

Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine. PMID:21135459

Van de Broek, B; Frederix, F; Bonroy, K; Jans, H; Jans, K; Borghs, G; Maes, G

2010-12-06

371

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

SciTech Connect

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.

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

2009-03-15

372

Influence of nanoparticle surface modification on the electrical behaviour of polyethylene nanocomposites  

NASA Astrophysics Data System (ADS)

In this study, we present the results of the influence of surface modification of TiO2 nanoparticles on the short-term breakdown strength and space charge distribution of low-density polyethylene (LDPE). A polar silane coupling agent N-(2-aminoethyl) 3-aminopropyl-trimethoxysilane (AEAPS) was used for the nanoparticle surface modification. Despite agglomeration and a poor interface compared to untreated nanoparticles, it was found that the incorporation of polar groups onto the nanoparticle surface improved both the dielectric breakdown strength and space charge distribution as compared to samples filled with untreated nanoparticles. Microstructure studies showed that the presence of polar groups on the TiO2 nanoparticle surface did not evidently affect the degree of crystallinity, crystalline morphology (except for internal spherulitic order), and chemical structure of the polymer matrix. The improved dielectric breakdown strength was therefore concluded to be directly due to beneficial effects related to the variation of the electrical features at the particle surface due to introduction of polar groups. For the same reason, with the use of surface modified nanoparticles, formation of space charge was suppressed.

Ma, Dongling; Hugener, Treese A.; Siegel, Richard W.; Christerson, Anna; Mårtensson, Eva; Önneby, Carina; Schadler, Linda S.

2005-06-01

373

Fabrication of 14 different RNA nanoparticles for specific tumor targeting without accumulation in normal organs.  

PubMed

Due to structural flexibility, RNase sensitivity, and serum instability, RNA nanoparticles with concrete shapes for in vivo application remain challenging to construct. Here we report the construction of 14 RNA nanoparticles with solid shapes for targeting cancers specifically. These RNA nanoparticles were resistant to RNase degradation, stable in serum for >36 h, and stable in vivo after systemic injection. By applying RNA nanotechnology and exemplifying with these 14 RNA nanoparticles, we have established the technology and developed "toolkits" utilizing a variety of principles to construct RNA architectures with diverse shapes and angles. The structure elements of phi29 motor pRNA were utilized for fabrication of dimers, twins, trimers, triplets, tetramers, quadruplets, pentamers, hexamers, heptamers, and other higher-order oligomers, as well as branched diverse architectures via hand-in-hand, foot-to-foot, and arm-on-arm interactions. These novel RNA nanostructures harbor resourceful functionalities for numerous applications in nanotechnology and medicine. It was found that all incorporated functional modules, such as siRNA, ribozymes, aptamers, and other functionalities, folded correctly and functioned independently within the nanoparticles. The incorporation of all functionalities was achieved prior, but not subsequent, to the assembly of the RNA nanoparticles, thus ensuring the production of homogeneous therapeutic nanoparticles. More importantly, upon systemic injection, these RNA nanoparticles targeted cancer exclusively in vivo without accumulation in normal organs and tissues. These findings open a new territory for cancer targeting and treatment. The versatility and diversity in structure and function derived from one biological RNA molecule implies immense potential concealed within the RNA nanotechnology field. PMID:23604636

Shu, Yi; Haque, Farzin; Shu, Dan; Li, Wei; Zhu, Zhenqi; Kotb, Malak; Lyubchenko, Yuri; Guo, Peixuan

2013-04-19

374

Gellan gum capped silver nanoparticle dispersions and hydrogels: cytotoxicity and in vitro diffusion studies  

NASA Astrophysics Data System (ADS)

The preparation of highly stable water dispersions of silver nanoparticles using the naturally available gellan gum as a reducing and capping agent is reported. Further, exploiting the gel formation characteristic of gellan gum silver nanoparticle incorporated gels have also been prepared. The optical properties, morphology, zeta potential and long-term stability of the synthesized silver nanoparticles were investigated. The superior stability of the gellan gum-silver nanoparticle dispersions against pH variation and electrolyte addition is revealed. Finally, we studied the cytotoxicity of AgNP dispersions in mouse embryonic fibroblast cells (NIH3T3) and also evaluated the in vitro diffusion of AgNP dispersions/gels across rat skin.The preparation of highly stable water dispersions of silver nanoparticles using the naturally available gellan gum as a reducing and capping agent is reported. Further, exploiting the gel formation characteristic of gellan gum silver nanoparticle incorporated gels have also been prepared. The optical properties, morphology, zeta potential and long-term stability of the synthesized silver nanoparticles were investigated. The superior stability of the gellan gum-silver nanoparticle dispersions against pH variation and electrolyte addition is revealed. Finally, we studied the cytotoxicity of AgNP dispersions in mouse embryonic fibroblast cells (NIH3T3) and also evaluated the in vitro diffusion of AgNP dispersions/gels across rat skin. Electronic supplementary information (ESI) available: Time dependent UV-Vis spectral studies revealing the stability of AgNP dispersions and agar plate images displaying the antibacterial activity of AgNPs. See DOI: 10.1039/c1nr10957j

Dhar, S.; Murawala, P.; Shiras, A.; Pokharkar, V.; Prasad, B. L. V.

2012-01-01

375

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

PubMed

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

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

2013-01-29

376

Spectral engineering of optical fiber through active nanoparticle doping  

NASA Astrophysics Data System (ADS)

The spectral engineering of optical fiber is a method of intentional doping of the core region in order to absorb/emit specific wavelengths of light therby providing enhanced performance over current fibers. Efforts here focused on developing an understanding of optically active nanoparticles based on alkaline earth fluorides that could be easily and homogeneously incorporated into the core of a silica based optical fiber preform and result in efficient and tailorable spectral emissions. Doped and undoped calcium, strontium and barium fluoride nanoparticles were successfully synthesized and characterized for their physical, chemical, and optical behavior. Distinct spectroscopic differences as a result of different host materials, varying rare earth doping levels and processing conditions, indicated the ability to influence the spectral behavior of the doped nanoparticle. By using photoluminescence to predict diffusion behavior, the application of a simple one dimensional model for diffusion provided a method for predicting the diffusion coefficient of europium ions in alkaline earth fluorides with order of magnitude accuracy. Modified chemical vapor deposition derived silica preforms were individually solution doped with europium doped alkaline earth fluoride nanoparticles. By using the rare earth doped alkaline earth fluoride nanoparticles as the dopant materials in the core of optical fiber preforms, the resultant optical properties of the glass were significantly influenced by their presence in the core. The incorporation of these rare earth doped alkaline earth fluoride nanoparticles was found to significantly influence the local chemical and structural environment about the rare earth ion, demonstrated homogeneity and uniform distribution of the rare earth dopant and resulted in specifically unique spectral behavior when compared to conventional doping methods. A more detailed structural model of the doped core glass region has been developed based on the spectral behavior of these active fiber preforms. It has been shown that rare earth doping of alkaline earth fluoride nanoparticles provides a material which can be 'tuned' to specific applications through the use of different host materials, processing conditions and doping levels of the rare earth and when used as dopant materials for active optical fibers, provides a means to tailor the optical behavior.

Lindstrom-James, Tiffany

377

Herbicidal effects of soil-incorporated wheat.  

PubMed

The hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and the benzoxazolinones benzoxazolin-2-one (BOA) and 6-methoxybenzoxazolin-2-one (MBOA) have been identified as important allelochemicals in wheat. This study examines the possibility of exploiting the allelopathic properties of wheat as a weed control strategy by cultivating wheat as a precrop and incorporating plant residues into the soil before the next crop is sown. Different wheat varieties were cultivated in field plots during two seasons in both conventional and organic farming systems. Plants were sampled at various growth stages, and their contents of DIMBOA, MBOA, and BOA were determined by chemical analyses. The wheat samples were incorporated into soil, and the effect on germination and growth of 12 different weed species was examined in pot experiments under controlled conditions. In some cases significant effects were obtained, but the results were inconsistent and the effects were not correlated to the content of DIMBOA, MBOA, and BOA in the incorporated wheat plants. ED50 doses of the pure compounds were estimated in dose-response experiments in Petri dishes, and these turned out to be much higher than the predicted maximum concentrations of DIMBOA, MBOA, and BOA in the soil water following incorporation. The study shows that a prerequisite for exploiting the incorporation of wheat residues as a weed control strategy is the development of wheat varieties with an increased content of allelochemicals. PMID:16478217

Mathiassen, Solvejg K; Kudsk, Per; Mogensen, Betty B

2006-02-22

378

Photoacoustic signal amplification through plasmonic nanoparticle aggregation  

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

379

Photoacoustic signal amplification through plasmonic nanoparticle aggregation.  

PubMed

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

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

2013-01-01

380

Surface- and hydrogel-mediated delivery of nucleic acid nanoparticles.  

PubMed

Gene expression within a cell population can be directly altered through gene delivery approaches. Traditionally for nonviral delivery, plasmids or siRNA molecules, encoding or targeting the gene of interest, are packaged within nanoparticles. These nanoparticles are then delivered to the media surrounding cells seeded onto tissue culture plastic; this technique is termed bolus delivery. Although bolus delivery is widely utilized to screen for efficient delivery vehicles and to study gene function in vitro, this delivery strategy may not result in efficient gene transfer for all cell types or may not identify those delivery vehicles that will be efficient in vivo. Furthermore, bolus delivery cannot be used in applications where patterning of gene expression is needed. In this chapter, we describe methods that incorporate material surfaces (i.e., surface-mediated delivery) or hydrogel scaffolds (i.e., hydrogel-mediated delivery) to efficiently deliver genes. This chapter includes protocols for surface-mediated DNA delivery focusing on the simplest and most effective methods, which include nonspecific immobilization of DNA complexes (both polymer and lipid vectors) onto serum-coated cell culture polystyrene and self-assembled monolayers of alkanethiols on gold. Also, protocols for the encapsulation of DNA/cationic polymer nanoparticles into hydrogel scaffolds are described, including methods for the encapsulation of low amounts of DNA (<0.2 ?g/?L) and high amounts of DNA (>0.2 ?g/?L) since incorporation of high amounts of DNA poses significant challenges due to aggregation. PMID:23070769

Pannier, Angela K; Segura, Tatiana

2013-01-01

381

Fabrication and hydrogen sorption behaviour of nanoparticulate MgH2 incorporated in a porous carbon host.  

PubMed

Nanoparticles of MgH2 incorporated in a mesoporous carbon aerogel demonstrated accelerated hydrogen exchange kinetics but no thermodynamic change in the equilibrium hydrogen pressure. Aerogels contained pores from <2 to approximately 30 nm in diameter with a peak at 13 nm in the pore size distribution. Nanoscale MgH2 was fabricated by depositing wetting layers of nickel or copper on the aerogel surface, melting Mg into the aerogel, and hydrogenating the Mg to MgH2. Aerogels with metal wetting layers incorporated 9-16 wt% MgH2, while a metal free aerogel incorporated only 3.6 wt% MgH2. The improved hydrogen sorption kinetics are due to both the aerogel limiting the maximum MgH(2) particle diameter and a catalytic effect from the Ni and Cu wetting layers. At 250 degrees C, MgH2 filled Ni decorated and Cu decorated carbon aerogels released H(2) at 25 wt% h(-1) and 5.5 wt% h(-1), respectively, while a MgH(2) filled aerogel without catalyst desorbed only 2.2 wt% h(-1) (all wt% h(-1) values are with respect to MgH2 mass). At the same temperature, MgH2 ball milled with synthetic graphite desorbed only 0.12 wt% h(-1), which demonstrated the advantage of incorporating nanoparticles in a porous host. PMID:19420653

Gross, Adam F; Ahn, Channing C; Van Atta, Sky L; Liu, Ping; Vajo, John J

2009-04-23

382

Vacancy Clusters at Nanoparticle Surfaces  

SciTech Connect

The authors detect vacancy clusters at Au nanoparticle surfaces using a combination of positron lifetime spectroscopy, 1- detector, and 2-detector measurements of Doppler broadening of annihilation radiation. Gold nanoparticles are formed by MeV implantation of gold ions into MgO (100) followed by annealing. Clusters of two Mg and two O vacancies (v{sub 4}) are attached to the gold nanoparticle surfaces within the projected range (R{sub p}).

Xu, J.; Moxom, J.; Somieski, B.; White, C.W.; Mills, A.P.; Suzuki, R.; Ishibashi, S.; Ueda, A.; Henderson, D.

2000-08-06

383

Glucose biosensor enhanced by nanoparticles  

Microsoft Academic Search

Glucose biosensors have been formed with glucose oxidase (GOD) immobilized in composite immobilization membrane matrix, which\\u000a is composed of hydrophobic gold, or hydrophilic gold, or hydrophobic silica nanoparticles, or the combination of gold and\\u000a silica nanoparticles, and polyvinyl butyral (PVB) by a sol-gel method. The experiments show that nanoparticles can significantly\\u000a enhance the catalytic activity of the immobilization enzyme. The

Fangqiong Tang; Xianwei Meng; Dong Chen; Junguo Ran; Changqiong Zheng

2000-01-01

384

Inorganic Nanoparticles in Cancer Therapy  

PubMed Central

Nanotechnology is an evolving field with enormous potential for biomedical applications. The growing interest to use inorganic nanoparticles in medicine is due to the unique size and shape-dependent optoelectronic properties. Herein, we will focus on gold, silver and platinum nanoparticles, discussing recent developments for therapeutic applications with regard to cancer in terms of nanoparticles being used as a delivery vehicle as well as therapeutic agents. We will also discuss some of the key challenges to be addressed in future studies.

Bhattacharyya, Sanjib; Kudgus, Rachel A.; Bhattacharya, Resham; Mukherjee, Priyabrata

2011-01-01

385

Nanobiotechnology today: focus on nanoparticles  

PubMed Central

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 .

Soloviev, Mikhail

2007-01-01

386

Nanobiotechnology today: focus on nanoparticles  

Microsoft Academic Search

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

Mikhail Soloviev

2007-01-01

387

Prospects for Organic Dye Nanoparticles  

Microsoft Academic Search

\\u000a \\u000a Abstract  A review of organic nanoparticles consisting of small functional dye molecules is presented in this chapter. The study of\\u000a organic dye nanoparticles does not have a lengthy history, but there is growing scientific and technological interest owing\\u000a to their special characteristics: physicochemical properties of organic dye nanoparticles considerably differ not only from\\u000a those of individual molecules due to the presence

Hiroshi Yao

388

Quantification of water exchange kinetics for targeted PARACEST perfluorocarbon nanoparticles  

PubMed Central

PARACEST (PARAmagnetic Chemical Exchange Saturation Transfer) agents offer the ability to generate “contrast on demand”, negating the need to image before contrast agent injection. Perfluorocarbon (PFC) nanoparticles can deliver very large payloads of PARACEST agents, lowering the effective detection limit for molecular imaging of sparse biomarkers. Also, the PFC core provides a quantitative 19F signal for measuring particle binding with high signal intensity and no background signal. 19F quantization coupled with mathematical modeling of the PARACEST signal showed that incorporating PARACEST chelates onto the nanoparticle surface reduces the bound water lifetime and diminishes the available contrast to noise ratio compared to the parent small molecule PARACEST chelate. PARACEST nanoparticles were targeted to fibrin, an early biomarker for atherosclerotic plaque rupture, and bound to the surface of in vitro clots, 2 yielding a detection limit of 2.30 nM at 11.7T. When the particles bind to a target surface the image contrast is higher than predicted from phantom experiments, perhaps due to improved water exchange kinetics. We have demonstrated that PARACEST PFC nanoparticles can provide two unique signatures, 19F and PARACEST, for quantitative targeted molecular imaging of fibrin.

Cai, Kejia; Kiefer, Garry E.; Caruthers, Shelton D.; Wickline, Samuel A.; Lanza, Gregory M.; Winter, Patrick M.

2013-01-01

389

Incorporating PET information in radiation therapy planning  

PubMed Central

PET scanning, because of its impressive sensitivity and accuracy, is being incorporated into the standard staging workup for many cancers. These include lung cancer, lymphomas, head and neck cancers, and oesophageal cancers. PET often provides incremental information about the patient’s disease status, adding to the data obtained from structural imaging methods, such as, CT scan or MRI. PET commonly upstages patients into more advanced disease categories. Incorporation of PET information into the radiotherapy planning process has the potential to reduce the risks of geographic miss and can help minimise unnecessary irradiation of normal tissues. The best means of incorporating PET information into radiotherapy planning is uncertain, and considerable effort is being expended in this area of research.

MacManus, M; Leong, T

2007-01-01

390

Some optical and catalytic properties of metallic nanoparticles  

NASA Astrophysics Data System (ADS)

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

Tabor, Christopher Eugene

391

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

392

Nanoparticles as 'smart' pharmaceutical delivery.  

PubMed

Pharmaceuticals in conjunction with nanoparticle delivery systems are growing towards new heights. The aim of this review is to gain a thorough understanding of different types and characteristics of nanoparticle based delivery systems, important properties of delivery systems, pharmaceutical ingredient loading and release in the nanoparticle delivery systems. In this review, we have also highlighted about the promising pharmaceutical deliveries like brain targeted delivery, ocular delivery, oral delivery, dermal and transdermal delivery, cancer chemotherapy, vaccine delivery, nucleic acids delivery and delivery system coupling to implants. A snapshot of the nanoparticle mediated drug deliveries which are commercially available and ongoing clinical trials have been provided. PMID:23747865

Chakraborty, Chiranjib; Pal, Soumen; Doss, George Priya C; Wen, Zhi-Hong; Lin, Chan-Shing

2013-06-01

393

Integration of gold nanoparticles into bilayer structures via adaptive surface chemistry.  

PubMed

We describe the spontaneous incorporation of amphiphilic gold nanoparticles (Au NPs) into the walls of surfactant vesicles. Au NPs were functionalized with mixed monolayers of hydrophilic (deprotonated mercaptoundecanoic acid, MUA) and hydrophobic (octadecanethiol, ODT) ligands, which are known to redistribute dynamically on the NP surface in response to changes in the local environment. When Au NPs are mixed with preformed surfactant vesicles, the hydrophobic ODT ligands on the NP surface interact favorably with the hydrophobic core of the bilayer structure and guide the incorporation of NPs into the vesicle walls. Unlike previous strategies based on small hydrophobic NPs, the present approach allows for the incorporation of water-soluble particles even when the size of the particles greatly exceeds the bilayer thickness. The strategy described here based on inorganic NPs functionalized with two labile ligands should in principle be applicable to other nanoparticle materials and bilayer structures. PMID:23565704

Lee, Hee-Young; Shin, Sun Hae Ra; Abezgauz, Ludmila L; Lewis, Sean A; Chirsan, Aaron M; Danino, Dganit D; Bishop, Kyle J M

2013-04-11

394

Therapy for incorporated radionuclides: scope and need  

SciTech Connect

In the United States the recent termination of funding for research on therapy for incorporated radionuclides has virtually halted progress on improved or new agents and procedures for removing radioactivity from the body. Research was eliminated, but is still needed on new removal agents, improved delivery system, in vitro test systems, and the toxicology of treatments. For many radionuclides, no adequate therapy exists. The relationship between radionuclide removal and reduction in cancer risk is still unanswered. Without proper research support, needed improvements in the treatment for incorporated radionuclides in the US are uncertain.

Smith, V.H.

1981-03-01

395

Incorporating Duration Information in Activity Recognition  

NASA Astrophysics Data System (ADS)

Activity recognition has become a key issue in smart home environments. The problem involves learning high level activities from low level sensor data. Activity recognition can depend on several variables; one such variable is duration of engagement with sensorised items or duration of intervals between sensor activations that can provide useful information about personal behaviour. In this paper a probabilistic learning algorithm is proposed that incorporates episode, time and duration information to determine inhabitant identity and the activity being undertaken from low level sensor data. Our results verify that incorporating duration information consistently improves the accuracy.

Chaurasia, Priyanka; Scotney, Bryan; McClean, Sally; Zhang, Shuai; Nugent, Chris

396

Physical and electrochemical characterizations of LiFePO 4 -incorporated Ag nanoparticles  

Microsoft Academic Search

Olivine-type LiFePO4 composite materials for cathode material of the lithium-ion batteries were synthesized by using a sol-gel method and were\\u000a coated by a chemical deposition of silver particles. As-obtained LiFePO4\\/C-Ag (2.1 wt.%) composites were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD),\\u000a conductivity measurements, cyclic voltammetry, as well as galvanostatic measurements. The results revealed that the discharge\\u000a capacity of

Zhaolin Liu; Siok Wei Tay; Liang Hong; Jim Yang Lee

2011-01-01

397

A phase I and pharmacokinetic study of NK105, a paclitaxel-incorporating micellar nanoparticle formulation  

PubMed Central

This phase I study was designed to examine the maximum tolerated dose (MTD), the dose-limiting toxicities (DLTs), the recommended dose (RD) for phase II, and the pharmacokinetics of NK105, a new polymeric micelle carrier system for paclitaxel (PTX). NK105 was administered as a 1-h intravenous infusion every 3 weeks, without antiallergic premedication. The starting dose was 10?mg?m?2, and the dose was escalated according to the accelerated titration method. Nineteen patients were recruited. The tumour types treated included pancreatic (n=11), bile duct (n=5), gastric (n=2), and colonic (n=1) cancers. Neutropenia was the most common haematological toxicity. A grade 3 fever developed in one patient given 180?mg?m?2. No other grades 3 or 4 nonhaematological toxicities, including neuropathy, was observed during the entire study period. DLTs occurred in two patients given 180?mg?m?2 (grade 4 neutropenia lasting for more than 5 days). Thus, this dose was designated as the MTD. Grade 2 hypersensitivity reactions developed in only one patient given 180?mg?m?2. A partial response was observed in one patient with pancreatic cancer. The maximum concentration (Cmax) and area under the concentration (AUC) of NK105 were dose dependent. The plasma AUC of NK105 at 150?mg?m?2 was approximately 15-fold higher than that of the conventional PTX formulation. NK105 was well tolerated, and the RD for the phase II study was determined to be 150?mg?m?2 every 3 weeks. The results of this phase I study warrant further clinical evaluation.

Hamaguchi, T; Kato, K; Yasui, H; Morizane, C; Ikeda, M; Ueno, H; Muro, K; Yamada, Y; Okusaka, T; Shirao, K; Shimada, Y; Nakahama, H; Matsumura, Y

2007-01-01

398

A phase I and pharmacokinetic study of NK105, a paclitaxel-incorporating micellar nanoparticle formulation  

Microsoft Academic Search

This phase I study was designed to examine the maximum tolerated dose (MTD), the dose-limiting toxicities (DLTs), the recommended dose (RD) for phase II, and the pharmacokinetics of NK105, a new polymeric micelle carrier system for paclitaxel (PTX). NK105 was administered as a 1-h intravenous infusion every 3 weeks, without antiallergic premedication. The starting dose was 10 mg m?2, and

T Hamaguchi; K Kato; H Yasui; C Morizane; M Ikeda; H Ueno; K Muro; Y Yamada; T Okusaka; K Shirao; Y Shimada; H Nakahama; Y Matsumura

2007-01-01

399

Nanoparticles for neuroimaging  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

400

Nanoparticle Reactions on Chip  

NASA Astrophysics Data System (ADS)

The handling of heterogenous systems in micro reactors is difficult due to their adhesion and transport behaviour. Therefore, the formation of precipitates and gas bubbles has to be avoided in micro reaction technology, in most cases. But, micro channels and other micro reactors offer interesting possibilities for the control of reaction conditions and transport by diffusion and convection due to the laminar flow caused by small Reynolds numbers. This can be used for the preparation and modification of objects, which are much smaller than the cross section of microchannels. The formation of colloidal solutions and the change of surface states of nano particles are two important tasks for the application of chip reactors in nanoparticle technology. Some concepts for the preparation and reaction of nanoparticles in modular chip reactor arrangements will be discussed.

Köhler, J. M.; Kirner, Th.; Wagner, J.; Csáki, A.; Möller, R.; Fritzsche, W.

401

Photoluminescence by Interstellar Nanoparticles  

SciTech Connect

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.

Witt, Adolf N. (University of Toledo)

2004-04-21

402

Nanoparticles via nanoprecipitation process.  

PubMed

Various encapsulation approaches have been explored during the last years in order to encapsulate classical active molecules and new synthesized molecules principally for the in vivo therapy as drug delivery nanocarriers and also for the in vivo biomedical diagnostic. These approaches lead to new and versatile systems exhibiting high encapsulation yields of small molecules mainly. Due to the use of biodegradable polymers, the final particles and dispersions exhibit low cytotoxicity and in some cases total biocompatibility. To enhance local targeting efficiency, nanoparticles are chemically grafted using specific antibody for a specific disease. One of the easiest processes leading to rapid particles formation is the nanoprecipitation. Such process is mainly based on polymer transfer from good solvent to poor solvent condition, leading consequently to nanoparticles formation via self-assembly of precipitated polymer chains. The article discussed some of patents associated with Nanoprecipitation Process. PMID:22845041

Minost, Audrey; Delaveau, Jean; Bolzinger, Marie-Alexandrine; Fessi, Hatem; Elaissari, Abdelhamid

2012-12-01

403

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

NASA Astrophysics Data System (ADS)

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.

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

2007-01-01

404

Layer-by-layer-assembled multilayer films of polyelectrolyte-stabilized surfactant micelles for the incorporation of noncharged organic dyes.  

PubMed

Noncharged pyrene molecules were incorporated into multilayer films by first loading pyrene into poly(acrylic acid) (PAA)-stabilized cetyltrimethylammonium bromide (CTAB) micelles (noted as PAA&(Py@CTAB)) and then layer-by-layer (LbL) assembled with poly(diallyldimethylammonium chloride) (PDDA). The stable incorporation of pyrene into multilayer films was confirmed by quartz crystal microbalance (QCM) measurements and UV-vis absorption spectroscopy. The resultant PAA&(Py@CTAB)/PDDA multilayer films show an exponential growth behavior because of the increased surface roughness with increasing number of film deposition cycles. The present study will open a general and cost-effective avenue for the incorporation of noncharged species, such as organic molecules, nanoparticles, and so forth, into LbL-assembled multilayer films by using polyelectrolyte-stabilized surfactant micelles as carriers. PMID:18928306

Liu, Xiaokong; Zhou, Lu; Geng, Wei; Sun, Junqi

2008-10-18

405

Nanoparticles in dermatology  

Microsoft Academic Search

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

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

406

Nanoparticle Toxicity Mechanisms: Genotoxicity  

NASA Astrophysics Data System (ADS)

Despite the relatively small amount of convincing experimental data, the potentially genotoxic nature of certain nanoparticles seems plausible, owing in particular to the presence of reactive oxygen species (ROS) such as the superoxide anion O2 • - , the hydroxyl radical • OH, and singlet oxygen 1O2, and reactive nitrogen species (RNS) such as nitrogen monoxide NO, the peroxynitrite anion ONOO - , the peroxynitrite radical ONOO • , and dinitrogen trioxide N2O3, a powerful nitration agent.

Botta, Alain; Benameur, La??la

407

Targeted Nanoparticle Subpopulation  

Microsoft Academic Search

The Filmix® nanoemulsion (including its self-assembling mixed-lipid nanoparticle subpopulations) is easily produced using a relatively mild dispersing technique. The small energy input needed for production of the Filmix® nanoemulsion (at room temperature) resembles the generally mild conditions under which SNEDDS (self-nanoemulsifying drug-delivery system(s)) are formed. Moreover, medium-chain and long-chain glycerides, which are employed for producing various SNEDDS reported in the

Joseph D'Arrigo

2011-01-01

408

Nanoparticle bridge DNA biosensor  

Microsoft Academic Search

A new DNA sensing method is demonstrated in which DNA hybridization events lead to the formation of nanoparticle satellites that bridge two electrodes and are detected electrically. The hybridization events are exclusively carried out only on specific locations, the surfaces of C-ssDNA modified 50 nm GNPs. The uniqueness of this work is that only a small number of T-ccDNA molecules

Hong-Wen Huang

2010-01-01

409

Electrodynamics of Noble Metal Nanoparticles and Nanoparticle Clusters  

Microsoft Academic Search

In this paper we examine the electrodynamics of silver nanoparticles and of clusters of nanoparticles, with an emphasis on extinction spectra and of electric fields near the particle surfaces that are important in determining surface-enhanced Raman (SER) intensities. The particles and clusters are chosen to be representative of what has been studied in recent work on colloids and with lithographically

Traci Jensen; Lance Kelly; Anne Lazarides; George C. Schatz

1999-01-01

410

Sensing with fluorescent nanoparticles  

NASA Astrophysics Data System (ADS)

Fluorescent chemosensors are chemical systems that can detect and signal the presence of selected analytes through variations in their fluorescence emission. Their peculiar properties make them arguably one of the most useful tools that chemistry has provided to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In its simplest design, a fluorescent chemosensor is composed of a fluorescent dye and a receptor, with a built-in transduction mechanism that converts recognition events into variations of the emission properties of the fluorescent dye. As soon as fluorescent nanoparticles became available, several applications in the field of sensing were explored. Nanoparticles have been used not only as better-performing substitutes of traditional dyes but also as multivalent scaffolds for the realization of supramolecular assemblies, while their high surface to volume ratio allows for distinct spatial domains (bulk, external surface, pores and shells) to be functionalized to a comparable extent with different organic species. Over the last few years, nanoparticles proved to be versatile synthetic platforms for the implementation of new sensing schemes.

Baù, Luca; Tecilla, Paolo; Mancin, Fabrizio

2011-01-01

411

Towards thiol functionalization of vanadium pentoxide nanotubes using gold nanoparticles  

SciTech Connect

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.

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

412

Picomolar sensitivity MRI and photoacoustic imaging of cobalt nanoparticles  

PubMed Central

Multimodality imaging based on complementary detection principles has broad clinical applications and promises to improve the accuracy of medical diagnosis. This means that a tracer particle advantageously incorporates multiple functionalities into a single delivery vehicle. In the present work, we explore a unique combination of MRI and photoacoustic tomography (PAT) to detect picomolar concentrations of nanoparticles. The nanoconstruct consists of ferromagnetic (Co) particles coated with gold (Au) for biocompatibility and a unique shape that enables optical absorption over a broad range of frequencies. The end result is a dual-modality probe useful for the detection of trace amounts of nanoparticles in biological tissues, in which MRI provides volume detection, whereas PAT performs edge detection.

Bouchard, Louis-S.; Anwar, M. Sabieh; Liu, Gang L.; Hann, Byron; Xie, Z. Harry; Gray, Joe W.; Wang, Xueding; Pines, Alexander; Chen, Fanqing Frank

2009-01-01

413

Gold nanoparticles in columnar matrix of discotic liquid crystal  

NASA Astrophysics Data System (ADS)

Hexanethiolate-stabilized gold nanoparticles (GNP) were synthesized by the method adopted by Song et al.[2]. Average size of GNPs was determined by scanning transmission electron microscopy (STEM). This method yielded nanoparticles with average particle size of 1.5 nm. In the present work, we have incorporated GNPs in columnar matrix of discotic liquid crystal. The thermo-physical properties of these mixtures were investigated using polarizing optical micrography (POM), differential scanning calorimetry (DSC) and dielectric spectroscopy. Results show GNPs does not affect the hexagonal arrangement of columns of DLC. However, there is decrease in mesophase to crystallization temperature as confirmed by DSC. This approach of crossing of the field of nanotechnology with DLC may lead to novel materials with interesting properties that are useful for many device applications.

Supreet; Kumar, Rishi; Pratibha, R.; Kumar, Sandeep; Raina, K. K.

2013-06-01

414

Incorporation of National Universities in Japan  

ERIC Educational Resources Information Center

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…

Oba, Jun

2007-01-01

415

Recursion Engineering for Reduction Incorporated Parsers  

Microsoft Academic Search

Reduction Incorporated (RI) recognisers and parsers deliver high performance by suppressing the stack activity except for those rules that generate fully embedded recursion. Automaton constructions for RI parsing have been presented by Aycock and Horspool [John Aycock and Nigel Horspool. Faster generalised LR parsing. In Compiler Construction, 8th Intnl. Conf, CC'99, volume 1575 of Lecture Notes in Computer Science, pages

Adrian Johnstone; Elizabeth Scott

2005-01-01

416

Design of Schools to Incorporate Fallout Protection.  

ERIC Educational Resources Information Center

Means are suggested by which a school district may incorporate low-cost fallout protection in a school construction program, through construction of an underground shelter beneath the concrete slab foundation. Ways of controlling distribution and filtering air are discussed. The author also suggests consideration of a completely underground…

Folley, Milo D.

417

Sequence mining in categorical domains: incorporating constraints  

Microsoft Academic Search

We present cSPADE, an ecient algorithm for mining fre- quent sequences considering a variety of syntactic constraints. These take the form of length or width limitations on the sequences, minimum or maximum gap constraints on con- secutive sequence elements, applying a time window on al- lowable sequences, incorporating item constraints, and Þnd- ing sequences predictive of one or more classes,

Mohammed Javeed Zaki

2000-01-01

418

Parameters influencing zeolite incorporation in PDMS membranes  

Microsoft Academic Search

The incorporation of several types of zeolite in PDMS membranes is studied, by measuring the tensile strength, xylene sorption, and density of the membranes. The zeolite is shown to be involved in the cross-linking of the membrane. The interaction between the PDMS matrix and the zeolites results in reinforced membranes in the case of zeolite Y. The parameters influencing the

Ivo F. J. Vankelecom; Else Scheppers; Robin Heus; Jan B. Uytterhoeven

1994-01-01

419

Incorporating Learning into the Cognitive Assessment Framework  

ERIC Educational Resources Information Center

|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…

Studer, Cassandra; Junker, Brian; Chan, Helen

2012-01-01

420

Methods of metal incorporation into intracellular granules  

Microsoft Academic Search

Summary The hepatopancreas of the garden snail (Helix aspersa) contains basophil cells which produce intracellular granules of CaMgP2O7. A variety of metals are incorporated into these granules either by direct substitution or by the synthesis of new pyrophosphate material.

K. Simkiss; K. G. A. Jenkins; Jill McLellan; Elizabeth Wheeler

1982-01-01