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Sample records for water-soluble gold nanoparticles

  1. Water-Soluble Gold Nanoparticles Protected by Fluorinated Amphiphilic Thiolates

    NARCIS (Netherlands)

    Gentilini, Cristina; Evangelista, Fabrizio; Rudolf, Petra; Franchi, Paola; Lucarini, Marco; Pasquato, Lucia

    2008-01-01

    The preparation and the properties of gold nanoparticles (Au NPs) protected by perfluorinated amphiphiles are described. The thiols were devised to form a perfluorinated region close to the gold surface and to have a hydrophilic portion in contact with the bulk solvent to impart solubility in water.

  2. Synthesis of water soluble chitosan stabilized gold nanoparticles and determination of uric acid

    Science.gov (United States)

    Lanh Le, Thi; Khieu Dinh, Quang; Hoa Tran, Thai; Nguyen, Hai Phong; Le Hien Hoang, Thi; Hien Nguyen, Quoc

    2014-06-01

    Gold nanoparticles (Au-NPs) have been successfully synthesized by utilizing water soluble chitosan as reducing and stabilizing agent. The colloidal Au-NPs were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The results showed that the colloidal Au-NPs had a plasmon absorption band with maximum wavelength in the range of 520-526 nm and the diameters were about 8-15 nm. In addition, a new Au-NPs-modified electrode was fabricated by self-assembling Au-NPs to the surface of the L-cysteine-modified glassy carbon electrode (Au-NPs/L-Cys/GCE). The Au-NPs-modified electrode showed an excellent character for electro-catalytic oxidization of uric acid (UA) in 0.1 mol L-1 phosphate buffer solution (pH 3.2). Using differential pulse anodic stripping voltammetry (DP-ASV), a high selectivity for determination of UA has been explored for the Au-NPs-modified electrode. DP-ASV peak currents of UA increased linearly with their concentration at the range of 2.0 × 10-6 to 4.0 × 10-5 mol L-1 with the detection limit of 2.7 × 10-6 mol L-1 for UA. The proposed method was applied for the detection of UA in human urine and serum samples with satisfactory results.

  3. Host-guest chemistry with water-soluble gold nanoparticle supraspheres

    Science.gov (United States)

    Wang, Yizhan; Zeiri, Offer; Raula, Manoj; Le Ouay, Benjamin; Stellacci, Francesco; Weinstock, Ira A.

    2017-02-01

    The uptake of molecular guests, a hallmark of the supramolecular chemistry of cages and containers, has yet to be documented for soluble assemblies of metal nanoparticles. Here we demonstrate that gold nanoparticle-based supraspheres serve as a host for the hydrophobic uptake, transport and subsequent release of over two million organic guests, exceeding by five orders of magnitude the capacities of individual supramolecular cages or containers and rivalling those of zeolites and metal-organic frameworks on a mass-per-volume basis. The supraspheres are prepared in water by adding hexanethiol to polyoxometalate-protected 4 nm gold nanoparticles. Each 200 nm assembly contains hydrophobic cavities between the estimated 27,400 gold building blocks that are connected to one another by nanometre-sized pores. This gives a percolated network that effectively absorbs large numbers of molecules from water, including 600,000, 2,100,000 and 2,600,000 molecules (35, 190 and 234 g l-1) of para-dichorobenzene, bisphenol A and trinitrotoluene, respectively.

  4. Highly sensitive visual detection of copper (II) using water-soluble azide-functionalized gold nanoparticles and silver enhancement.

    Science.gov (United States)

    Zhang, Zhen; Li, Wenqing; Zhao, Qiuling; Cheng, Ming; Xu, Li; Fang, Xiaohong

    2014-09-15

    A high-sensitive method for the visual detection of copper ions in aqueous solution is developed. The method is based on copper ion-catalyzed 'click' reaction between the water-soluble azide-functionalized gold nanoparticles (AuNPs) and alkyne-modified glass slide. The PEG linker was employed as a stabilizing component along with the terminal azide group to keep the AuNPs stably dispersed in water without the assistance of any organic solvent. In the presence of copper ions, the AuNPs are 'clicked' on the slide, and the darkness of the AuNPs in the sample spot is promoted by silver enhancement process. Only a tiny amount of sample (10 μl) is needed with the detectable concentration down to 62 pM by the commonly used flatbed scanner, which is 2-3 orders of magnitude lower than those in previous reports. The selectivity relative to other potentially interfering ions and the applicability in real samples, human serum and tap water, have also been evaluated. Our method has a good potential in point-of-use applications and environment surveys. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Size-Dependent Photodynamic Activity of Gold Nanoparticles Conjugate of Water Soluble Purpurin-18-N-Methyl-D-Glucamine

    Directory of Open Access Journals (Sweden)

    Byambajav Lkhagvadulam

    2013-01-01

    Full Text Available Gold nanoparticles (GNPs conjugates of water soluble ionic photosensitizer (PS, purpurin-18-N-methyl-D-glucamine (Pu-18-NMGA, were synthesized using various molar ratios between HAuCl4 and Pu-18-NMGA without adding any particular reducing agents and surfactants. The PS-GNPs conjugates showed long wavelength absorption of range 702–762 nm, and their different shapes and diameters depend on the molar ratios used in the synthesis. In vitro anticancer efficacy of the PS-GNPs conjugates was investigated by MTT assay against A549 cells, resulting in higher photodynamic activity than that of the free Pu-18-NMGA. Among the PS-GNPs conjugates, the GNPs conjugate from the molar ratio of 1 : 2 (Au(III: Pu-18-NMGA exhibits the highest photodynamic activity corresponding to bigger size (~60 nm of the GNPs conjugate which could efficiently transport the PS into the cells than that of smaller size of the GNPs conjugate.

  6. Newly Synthesized Water Soluble Cholinium-Purpurin Photosensitizers and Their Stabilized Gold Nanoparticles as Promising Anticancer Agents

    Directory of Open Access Journals (Sweden)

    Young Key Shim

    2008-05-01

    Full Text Available For possible future use in Photodynamic Therapy (PDT and/or Photothermal Therapy (PTT of cancer and screening of cancer cells a new type of ionic liquid photosensitizer –Cholinium-Purpurin-18 (Chol-Pu-18 – was synthesized and small gold (Au nanoparticles, stabilized by this photosensitizer were prepared without adding any particular reducing agents and CTAB. UV-Vis spectroscopy and Transmission Electron Microscopy (TEM were used for characterization of the nanoparticles and FAB-MS and NMR of the ionic liquid choline hydroxide, purpurin carboxylate and their ionic liquid type of photosensitizer were obtained.

  7. Electron beam induced water-soluble silk fibroin nanoparticles as a natural antioxidant and reducing agent for a green synthesis of gold nanocolloid

    Science.gov (United States)

    Wongkrongsak, Soraya; Tangthong, Theeranan; Pasanphan, Wanvimol

    2016-01-01

    The research proposes a novel water-soluble silk fibroin nanoparticles (WSSF-NPs) created by electron beam irradiation. In this report, we demonstrate the effects of electron beam irradiation doses ranging from 1 to 30 kGy on the molecular weight (MW), nanostructure formation, antioxidant activity and reducing power of the WSSF-NPs. Electron beam-induced degradation of SF causing MW reduction from 250 to 37 kDa. Chemical characteristic functions of SF still remained after exposing to electron beam. The WSSF-NPs with the MW of 37 kDa exhibited spherical morphology with a nanoscaled size of 40 nm. Antioxidant activities and reducing powers were investigated using 2,2-diphenyl-1-picrylhryl free radical (DPPH•) scavenging activity and ferric reducing antioxidant power (FRAP) assays, respectively. The WSSF-NPs showed greater antioxidant activity and reducing power than non-irradiated SF. By increasing their antioxidant and reducing power efficiencies, WSSF-NPs potentially created gold nanocolloid. WSSF-NPs produced by electron beam irradiation would be a great merit for the uses as a natural antioxidant additive and a green reducing agent in biomedical, cosmetic and food applications.

  8. Thiolate ligands for synthesis of water-soluble gold clusters.

    Science.gov (United States)

    Ackerson, Christopher J; Jadzinsky, Pablo D; Kornberg, Roger D

    2005-05-11

    Water-soluble monolayer-protected gold clusters (MPCs) have been an object of investigation by many research groups since their first syntheses were reported in 1998 and 1999. The basic requirements for a ligand to form a monolayer protecting a gold cluster were established some time ago for alkanethiolate MPCs, but there has been no such information published for water-soluble MPCs. We identify 6 new ligands capable of forming water-soluble MPCs, as well as 22 water-soluble ligands that fail to form MPCs. Our findings contribute not only to the definition of the requirements for MPC formation but also to the variety of MPCs available for applications in chemistry and biology.

  9. Ion-pair chromatographic separation of water-soluble gold monolayer-protected clusters.

    Science.gov (United States)

    Choi, Martin M F; Douglas, Alicia D; Murray, Royce W

    2006-04-15

    We demonstrate the efficacy of ion-pair chromatography for separations of samples of charged, polydisperse, water-soluble gold nanoparticles protected by monolayers of N-acetyl-l-cysteine and of tiopronin ligands. These nanoparticle mixtures have 1-2-nm-diameter Au core sizes as estimated from UV-visible spectra of the separated components. This size range encompasses the transition from bulk metal to molecular properties. The nanoparticle mixtures were resolved, the smallest nanoparticles eluting first, on an octadecylsilyl (C18) column using isocratic elution with a methanol/water mobile phase containing tetrabutylammonium fluoride (Bu4N+F-) and phosphate buffer. The column retention increases with Bu4N+F- concentration, lowered pH, and decreasing methanol volume fraction. The retention mechanism is dominated by ion-pairing in either the mobile phase or at the stationary/mobile-phase interface. Size exclusion effects, used in many previous nanoparticle separations, are insignificant.

  10. Water-soluble magnetic nanoparticles with biologically active stabilizers

    Science.gov (United States)

    Zablotskaya, Alla; Segal, Izolda; Lukevics, Edmunds; Maiorov, Mikhail; Zablotsky, Dmitry; Blums, Elmars; Shestakova, Irina; Domracheva, Ilona

    2009-05-01

    We present the results of the interaction of iron oxide nanoparticles with some biologically active surfactants, namely, oleic acid and cytotoxic alkanolamine derivatives. Physico-chemical properties, as magnetization, magnetite concentration and particle diameter, of the prepared magnetic samples were studied. The nanoparticle size of 11 nm for toluene magnetic fluid determined by TEM is in good agreement with the data obtained by the method of magnetogranulometry. In vitro cytotoxic effect of water-soluble nanoparticles with different iron oxide:oleic acid molar ratio were revealed against human fibrosarcoma and mouse hepatoma cells. In vivo results using a sarcoma mouse model showed observable antitumor action.

  11. Water-soluble magnetic nanoparticles with biologically active stabilizers

    Energy Technology Data Exchange (ETDEWEB)

    Zablotskaya, Alla [Latvian Institute of Organic Synthesis, 21 Aizkraukles Street, Riga LV-1006 (Latvia)], E-mail: aez@osi.lv; Segal, Izolda; Lukevics, Edmunds [Latvian Institute of Organic Synthesis, 21 Aizkraukles Street, Riga LV-1006 (Latvia); Maiorov, Mikhail; Zablotsky, Dmitry; Blums, Elmars [Institute of Physics, University of Latvia, 32 Miera, Salaspils LV-2169 (Latvia); Shestakova, Irina; Domracheva, Ilona [Latvian Institute of Organic Synthesis, 21 Aizkraukles Street, Riga LV-1006 (Latvia)

    2009-05-15

    We present the results of the interaction of iron oxide nanoparticles with some biologically active surfactants, namely, oleic acid and cytotoxic alkanolamine derivatives. Physico-chemical properties, as magnetization, magnetite concentration and particle diameter, of the prepared magnetic samples were studied. The nanoparticle size of 11 nm for toluene magnetic fluid determined by TEM is in good agreement with the data obtained by the method of magnetogranulometry. In vitro cytotoxic effect of water-soluble nanoparticles with different iron oxide:oleic acid molar ratio were revealed against human fibrosarcoma and mouse hepatoma cells. In vivo results using a sarcoma mouse model showed observable antitumor action.

  12. Size-Controlled Water-Soluble Ag Nanoparticles

    OpenAIRE

    Dominguez-Vera, J. M.; Galvez, N.; Sanchez, P; A. J. Mota; Trasobares Llorente, Susana; Hernandez, J.C.; Calvino Gámez, José Juan

    2007-01-01

    Ag nanoparticles of two different sizes (1 and 4 nm) were prepared within an apoferritin cavity by using an Ag+-loaded apoferritin as a nanoconfined environment for their construction. The initial amount of Ag' ions injected in the apoferritin cavity dictates the size of the final Ag particles. The protein shell prevents bulk aggregation of the metal particles, which renders them water soluble and extremely stable.

  13. De novo design and synthesis of water-soluble gold(I) compounds ...

    Indian Academy of Sciences (India)

    Administrator

    De novo design and synthesis of water-soluble gold(I) compounds: ... specific transition metal precursors) is central to the design and development of transition metal-based compounds that meet certain ... also brings about kinetic inertness, over a wide range of pH, in aqueous media 1,2. Gold compounds have been ...

  14. Photoluminescence of water-soluble NdF nanoparticles by codoping Li or Ba ions

    Science.gov (United States)

    Fan, Ting; Lü, Jiantao; Li, Na; Han, Dingan

    2013-02-01

    Water-soluble NdF3, NdF3:Li+, and NdF3:Ba nanoparticles coated with polyvinylpyrrolidone were synthesized by a simple hydrothermal method. The products were characterized by x-ray diffraction, field-emission scanning electron microscopy, and photoluminescence spectra at room temperature. Codoping with Li+ ions does not change the emission intensity of water-soluble NdF3 nanoparticles, whereas codoping with Ba ions improves the near-infrared emissions.

  15. Synthesis of water soluble glycine capped silver nanoparticles and their surface selective interaction

    Energy Technology Data Exchange (ETDEWEB)

    Agasti, Nityananda, E-mail: nnagasti@gmail.com [Department of Chemistry, University of Delhi, Delhi 110007 (India); Singh, Vinay K. [Department of Chemistry, Sri Aurobindo College, University of Delhi, Delhi 110017 (India); Kaushik, N.K. [Department of Chemistry, University of Delhi, Delhi 110007 (India)

    2015-04-15

    Highlights: • Synthesis of water soluble silver nanoparticles at ambient reaction conditions. • Glycine as stabilizing agent for silver nanoparticles. • Surface selective interaction of glycine with silver nanoparticles. • Glycine concentration influences crystalinity and optical property of silver nanoparticles. - Abstract: Synthesis of biocompatible metal nanoparticles has been an area of significant interest because of their wide range of applications. In the present study, we have successfully synthesized water soluble silver nanoparticles assisted by small amino acid glycine. The method is primarily based on reduction of AgNO{sub 3} with NaBH{sub 4} in aqueous solution under atmospheric air in the presence of glycine. UV–vis spectroscopy, transmission electron microscopy (TEM), X–ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG) and differential thermal analysis (DTA) techniques used for characterization of resulting silver nanoparticles demonstrated that, glycine is an effective capping agent to stabilize silver nanoparticles. Surface selective interaction of glycine on (1 1 1) face of silver nanoparticles has been investigated. The optical property and crystalline behavior of silver nanoparticles were found to be sensitive to concentration of glycine. X–ray diffraction studies ascertained the phase specific interaction of glycine on silver nanoparticles. Silver nanoparticles synthesized were of diameter 60 nm. We thus demonstrated an efficient synthetic method for synthesis of water soluble silver nanoparticles capped by amino acid under mild reaction conditions with excellent reproducibility.

  16. Water-soluble PEGylated silicon nanoparticles and their assembly into swellable nanoparticle aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zejing; Li, Yejia; Zhang, Boyu; Purkait, Tapas [Tulane University, Department of Chemistry (United States); Alb, Alina [Tulane University, Department of Physics and Engineering Physics (United States); Mitchell, Brian S. [Tulane University, Department of Chemical and Biomolecular Engineering (United States); Grayson, Scott M.; Fink, Mark J., E-mail: fink@tulane.edu [Tulane University, Department of Chemistry (United States)

    2015-01-15

    Water-soluble silicon nanoparticles were synthesized by grafting PEG polymers onto functionalized silicon nanoparticles with distal alkyne or azide moieties. The surface-functionalized silicon nanoparticles were produced in one step from the reactive high-energy ball milling (RHEBM) of silicon wafers with a mixture of either 5-chloro-1-pentyne in 1-pentyne or 1,7 octadiyne in 1-hexyne to afford air and water-stable chloroalkyl or alkynyl-terminated nanoparticles, respectively. Nanoparticles with the ω-chloroalkyl substituents were easily converted to ω-azidoalkyl groups through the reaction of the Si nanoparticles with sodium azide in DMF. The azido-terminated nanoparticles were then grafted with mono-alkynyl-PEG polymers using a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction to afford core–shell silicon nanoparticles with a covalently attached PEG shell. Covalently linked Si nanoparticle clusters were synthesized via the CuAAC “click” reaction of functional Si NPs with α,ω-functional PEG polymers of various lengths. Dynamic light scattering studies show that the flexible globular nanoparticle aggregates undergo a solvent-dependent change in volume (ethanol > dichloromethane > toluene) similar in behavior to hydrogel nanocomposites.

  17. Synthesis and Size Dependent Reflectance Study of Water Soluble SnS Nanoparticles

    Directory of Open Access Journals (Sweden)

    Richard D. Tilley

    2012-01-01

    Full Text Available Near-monodispersed water soluble SnS nanoparticles in the diameter range of 3–6 nm are synthesized by a facile, solution based one-step approach using ethanolamine ligands. The optimal amount of triethanolamine is investigated. The effect of further heat treatment on the size of these SnS nanoparticles is discussed. Diffuse reflectance study of SnS nanoparticles agrees with predictions from quantum confinement model.

  18. EPR and Structural Characterization of Water-Soluble Mn2+-Doped Si Nanoparticles

    OpenAIRE

    Atkins, Tonya M.; Walton, Jeffrey H.; Singh, Mani P.; Ganguly, Shreyashi; Janka, Oliver; Louie, Angelique Y.; Kauzlarich, Susan M.

    2016-01-01

    Water-soluble poly(allylamine) Mn2+-doped Si (SiMn) nanoparticles (NPs) were prepared and show promise for biologically related applications. The nanoparticles show both strong photoluminescence and good magnetic resonance contrast imaging. The morphology and average diameter were obtained through transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM); spherical crystalline Si NPs with an average diameter of 4.2 ? 0.7 nm were observed. The doping m...

  19. Nanoformulation and encapsulation approaches for poorly water-soluble drug nanoparticles

    Science.gov (United States)

    Wais, Ulrike; Jackson, Alexander W.; He, Tao; Zhang, Haifei

    2016-01-01

    During the last few decades the nanomedicine sector has emerged as a feasible and effective solution to the problems faced by the high percentage of poorly water-soluble drugs. Decreasing the size of such drug compounds to the nanoscale can significantly change their physical properties, which lays the foundation for the use of nanomedicine for pharmaceutical applications. Various techniques have been developed to produce poorly water-soluble drug nanoparticles, mainly to address the poor water-soluble issues but also for the efficient and targeted delivery of such drugs. These techniques can be generally categorized into top-down, bottom-up and encapsulation approaches. Among them, the top-down approaches have been the main choice for industrial preparation of drug nanoparticles while other methods are actively investigated by researchers. In this review, we aim to give a comprehensive overview and latest progress of the top-down, bottom-up, and encapsulation methods for the preparation of poorly water-soluble drug nanoparticles and how solvents and additives can be selected for these methods. In addition to the more industrially applied top-down approaches, the review is focused more on bottom-up and encapsulation methods, particularly covering supercritical fluid-related methods, cryogenic techniques, and encapsulation with dendrimers and responsive block copolymers. Some of the approved and mostly used nanodrug formulations on the market are also covered to demonstrate the applications of poorly water-soluble drug nanoparticles. This review is complete with perspectives on the development and challenges of fabrication techniques for more effective nanomedicine.

  20. Water-soluble triscyclometalated organoiridium complex: phosphorescent nanoparticle formation, nonlinear optics, and application for cell imaging.

    Science.gov (United States)

    Fan, Yuanpeng; Zhao, Jingyi; Yan, Qifan; Chen, Peng R; Zhao, Dahui

    2014-03-12

    Two water-soluble triscyclometalated organoiridium complexes, 1 and 2, with polar side chains that form nanoparticles emitting bright-red phosphorescence in water were synthesized. The optimal emitting properties are related to both the triscyclometalated structure and nanoparticle-forming ability in aqueous solution. Nonlinear optical properties are also observed with the nanoparticles. Because of their proper cellular uptake in addition to high emission brightness and effective two-photon absorbing ability, cell imaging can be achieved with nanoparticles of 2 bearing quaternary ammonium side chains at ultra-low effective concentrations using NIR incident light via the multiphoton excitation phosphorescence process.

  1. Facile preparation of water-soluble fluorescent gold nanoclusters for cellular imaging applications

    Science.gov (United States)

    Shang, Li; Dörlich, René M.; Brandholt, Stefan; Schneider, Reinhard; Trouillet, Vanessa; Bruns, Michael; Gerthsen, Dagmar; Nienhaus, G. Ulrich

    2011-05-01

    We report a facile strategy to synthesize water-soluble, fluorescent gold nanoclusters (AuNCs) in one step by using a mild reductant, tetrakis(hydroxymethyl)phosphonium chloride (THPC). A zwitterionic functional ligand, d-penicillamine (DPA), as a capping agent endowed the AuNCs with excellent stability in aqueous solvent over the physiologically relevant pH range. The DPA-capped AuNCs displayed excitation and emission bands at 400 and 610 nm, respectively; the fluorescence quantum yield was 1.3%. The effect of borohydride reduction on the optical spectra and X-ray photoelectron spectroscopy (XPS) results indicated that the AuNC luminescence is closely related to the presence of Au(i) on their surfaces. In a first optical imaging application, we studied internalization of the AuNCs by live HeLa cells using confocal microscopy with two-photon excitation. A cell viability assay revealed good biocompatibility of these AuNCs. Our studies demonstrate a great potential of DPA-stabilized AuNCs as fluorescent nanoprobes in bioimaging and related applications.We report a facile strategy to synthesize water-soluble, fluorescent gold nanoclusters (AuNCs) in one step by using a mild reductant, tetrakis(hydroxymethyl)phosphonium chloride (THPC). A zwitterionic functional ligand, d-penicillamine (DPA), as a capping agent endowed the AuNCs with excellent stability in aqueous solvent over the physiologically relevant pH range. The DPA-capped AuNCs displayed excitation and emission bands at 400 and 610 nm, respectively; the fluorescence quantum yield was 1.3%. The effect of borohydride reduction on the optical spectra and X-ray photoelectron spectroscopy (XPS) results indicated that the AuNC luminescence is closely related to the presence of Au(i) on their surfaces. In a first optical imaging application, we studied internalization of the AuNCs by live HeLa cells using confocal microscopy with two-photon excitation. A cell viability assay revealed good biocompatibility of these Au

  2. Nanoparticle formation of poorly water-soluble drugs from ternary ground mixtures with PVP and SDS.

    Science.gov (United States)

    Itoh, Koichi; Pongpeerapat, Adchara; Tozuka, Yuichi; Oguchi, Toshio; Yamamoto, Keiji

    2003-02-01

    Poorly water-soluble drugs N-5159, griseofulvin (GFV), glibenclamide (GBM) and nifedipine (NFP) were ground in a dry process with polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS). Different crystallinity behavior of each drug during grinding was shown in the ternary Drug/PVP/SDS system. However, when each ternary Drug/PVP/SDS ground mixture was added to distilled water, crystalline nanoparticles which were 200 nm or less in size were formed and had excellent stability. Zeta potential measurement suggested that the nanoparticles had a structure where SDS was adsorbed onto the particles that were formed by the adsorption of PVP on the surface of drug crystals. Stable existence of crystalline nanoparticles was attributable to the inhibition of aggregation caused by the adsorption of PVP and SDS on the surface of drug crystals. Furthermore, the electrostatic repulsion due to the negative charge of SDS on a shell of nanoparticles could be assumed to contribute to the stable dispersion.

  3. Highly Water-Soluble Magnetic Nanoparticles as Novel Draw Solutes in Forward Osmosis for Water Reuse

    KAUST Repository

    Ling, Ming Ming

    2010-06-16

    Highly hydrophilic magnetic nanoparticles have been molecularly designed. For the first time, the application of highly water-soluble magnetic nanoparticles as novel draw solutes in forward osmosis (FO) was systematically investigated. Magnetic nanoparticles functionalized by various groups were synthesized to explore the correlation between the surface chemistry of magnetic nanoparticles and the achieved osmolality. We verified that magnetic nanoparticles capped with polyacrylic acid can yield the highest driving force and subsequently highest water flux among others. The used magnetic nanoparticles can be captured by the magnetic field and recycled back into the stream as draw solutes in the FO process. In addition, magnetic nanoparticles of different diameters were also synthesized to study the effect of particles size on FO performance. We demonstrate that the engineering of surface hydrophilicity and magnetic nanoparticle size is crucial in the application of nanoparticles as draw solutes in FO. It is believed that magnetic nanoparticles will soon be extensively used in this area. © 2010 American Chemical Society.

  4. Cytotoxicity evaluation and antimicrobial studies of starch capped water soluble copper nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Valodkar, Mayur; Rathore, Puran Singh [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat (India); Jadeja, Ravirajsinh N.; Thounaojam, Menaka; Devkar, Ranjitsinh V. [Department of Zoology, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat (India); Thakore, Sonal, E-mail: chemistry2797@yahoo.com [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, Gujarat (India)

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer Bactericidal action of water soluble starch copper nanoconjugate was investigated. Black-Right-Pointing-Pointer Mode of action comparable to ampicillin and MIC as low as 1.6 {mu}g/ml. Black-Right-Pointing-Pointer The SCuNPs were non-toxic to mouse embryonic fibroblasts. Black-Right-Pointing-Pointer Cell viability was higher than uncapped CuNPs and cupric ions. Black-Right-Pointing-Pointer Promising biomedical applications due to high therapeutic index. - Abstract: Water soluble monodisperse copper nanoparticles of about 10 nm diameter were prepared by microwave irradiation using starch as green capping agent. The resulting Cu-starch conjugate were characterized by FTIR and energy dispersive X-ray analysis (EDX). The study confirmed the presence of copper embedded in polysaccharide matrix. The aqueous solution of starch capped copper nanoparticles (SCuNPs) exhibited excellent bactericidal action against both gram negative and gram positive bacteria. The in vitro cytotoxicity evaluation of the nanoparticles was carried out using mouse embryonic fibroblast (3T3L1) cells by MTT cell viability assay, extracellular lactate dehydrogenase (LDH) release and dark field microscopy imaging. The capped nanoparticles exhibited cytotoxicity at much higher concentration compared to cupric ions. Minimum bactericidal concentration (MBC) of SCuNPs was well below the in vitro cytotoxic concentration. Statistical analysis demonstrated p < 0.05 for significant results and p > 0.05 for non-significant ones as compared to untreated cells. The non-cytotoxic green Cu-starch conjugate offers a rational approach towards antimicrobial application and for integration to biomedical devices.

  5. Synthesis and studies of water-soluble Prussian Blue-type nanoparticles into chitosan beads.

    Science.gov (United States)

    Folch, Benjamin; Larionova, Joulia; Guari, Yannick; Molvinger, Karine; Luna, Carlos; Sangregorio, Claudio; Innocenti, Claudia; Caneschi, Andrea; Guérin, Christian

    2010-10-21

    A new approach to the synthesis of highly stable aqueous colloids of coordination polymer nanoparticles was developed by using water-soluble chitosan beads as template and as stabilizing agent. The method consists in the synthesis of nanocomposite beads containing cyano-bridged coordination polymer nanoparticles via step-by-step coordination of the metal ions and the hexacyanometallate precursors into the chitosan pores and then water solubilization of these as-obtained nanocomposite beads. We obtain a large range of M(2+)/[M'(CN)(6)](3-)/chitosan (where M(2+) = Ni(2+), Cu(2+), Fe(2+), Co(2+), Mn(2+) and M' = Fe(3+) and Cr(3+)) nanocomposite beads and their respective aqueous colloids containing coordination polymer core/chitosan shell nanoparticles. The nanocomposite beads and the corresponding aqueous colloids were studied by Infrared (IR) and UV-Vis spectroscopy, nitrogen sorption (BET), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM) and magnetic analyses, which reveal the presence of homogeneously dispersed uniformly-sized cyano-bridged coordination polymer nanoparticles. The detailed studies of the static and dynamic magnetic properties of these nanoparticles show the occurrence of a spin-glass like behavior presumably produced by intra-particle spin disorder due to the low spin exchange energy characterizing these materials.

  6. One-pot synthesis of water soluble iron nanoparticles using rationally-designed peptides and ligand release.

    Science.gov (United States)

    Papst, Stefanie; Cheong, Soshan; Banholzer, Moritz J; Brimble, Margaret A; Williams, David E; Tilley, Richard D

    2013-05-18

    Herein we report the rational design of new phosphopeptides for control of nucleation, growth and aggregation of water-soluble, superparamagnetic iron-iron oxide core-shell nanoparticles. The use of the designed peptides enables a one-pot synthesis that avoids utilizing unstable or toxic iron precursors, organic solvents, and the need for exchange of capping agent after synthesis of the NPs.

  7. Preparation and characterization of water-soluble albumin-bound curcumin nanoparticles with improved antitumor activity.

    Science.gov (United States)

    Kim, Tae Hyung; Jiang, Hai Hua; Youn, Yu Seok; Park, Chan Woong; Tak, Kyung Kook; Lee, Seulki; Kim, Hyungjun; Jon, Sangyong; Chen, Xiaoyuan; Lee, Kang Choon

    2011-01-17

    Curcumin (CCM), a yellow natural polyphenol extracted from turmeric (Curcuma longa), has potent anti-cancer properties as has been demonstrated in various human cancer cells. However, the widespread clinical application of this efficient agent in cancer and other diseases has been limited by its poor aqueous solubility and bioavailability. In this study, we prepared novel CCM-loaded human serum albumin (HSA) nanoparticles (CCM-HSA-NPs) for intravenous administration using albumin bound technology. Field emission scanning electron microscopy (FE-SEM) and dynamic light scattering (DLS) investigation confirmed a narrow size distribution in the 130-150nm range. Furthermore, CCM-HSA-NPs showed much greater water solubility (300-fold) than free CCM, and on storage, the biological activity of CCM-HSA-NPs was preserved with negligible activity loss. In vivo distributions and vascular endothelial cells transport studies demonstrated the superiority of CCM-HSA-NPs over CCM. Amounts of CCM in tumors after treatment with CCM-HSA-NPs were about 14 times higher at 1h after injection than that achieved by CCM. Furthermore, vascular endothelial cell binding of CCM increased 5.5-fold, and transport of CCM across a vascular endothelial cell monolayer by Transwell testing was 7.7-fold greater for CCM-HSA-NPs than CCM. Finally, in vivo antitumor tests revealed that CCM-HSA-NPs (10 or 20mg/kg) had a greater therapeutic effect (50% or 66% tumor growth inhibition vs. PBS-treated controls) than CCM (18% inhibition vs. controls) in tumor xenograft HCT116 models without inducing toxicity. We attribute this potent antitumor activity of CCM-HSA-NPs to enhanced water solubility, increased accumulation in tumors, and an ability to traverse vascular endothelial cell. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Spectral manifestation of surface plasmon resonance of silver nanoparticles upon interaction with water-soluble metalloporphyrins

    Science.gov (United States)

    Panarin, A. Yu.; Abakshonok, A. V.; Eremin, A. N.; Terekhov, S. N.

    2017-06-01

    Absorption and resonant light-scattering spectra of nanoparticles (NPs) of silver, and their complexes with water-soluble Cu(II)-5,10,15,20-tetrakis(4-N-methylpyridinium)-porphyrin (CuTMpyP4) and Fe(II)-5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (FeTSPP) have been compared. It is shown that in the presence of cationic CuTMpyP4, the band of surface plasmon resonance in the absorption and resonant scattering spectra of silver NPs is shifted to the long-wavelength region that is associated with the agglomeration of the particles caused by the Coulomb attraction between the silver particles and the porphyrin molecules. Addition of anionic FeTSPP to the silver NP solution does not lead to any spectral changes. The observed effect of silver-NP association induced by the cationic porphyrin can be used to develop an optical method for the detection of nanoparticles in solutions.

  9. Magnetic hyperthermia studies on water-soluble polyacrylic acid-coated cobalt ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Krishna Surendra, M. [Indian Institute of Technology Madras, Department of Physics, Nano Functional Materials Technology Centre, Materials Research Centre (India); Annapoorani, S. [Anna University of Technology, Department of Nanotechnology (India); Ansar, Ereath Beeran; Harikrishna Varma, P. R. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Bioceramics Laboratory (India); Ramachandra Rao, M. S., E-mail: msrrao@iitm.ac.in [Indian Institute of Technology Madras, Department of Physics, Nano Functional Materials Technology Centre, Materials Research Centre (India)

    2014-12-15

    We report on synthesis and hyperthermia studies in the water-soluble ferrofluid made of polyacrylic acid-coated cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with different particle sizes. Magnetic nanoparticles were synthesized using co-precipitation method and particle size was varied as 6, 10, and 14 nm by varying the precursor to surfactant concentration. PAA surfactant bonding and surfactant thickness were studied by FTIR and thermogravimetric analysis. At room temperature, nanoparticles show superparamagnetism and saturation magnetization was found to vary from 33 to 44 emu/g with increase in the particle size from 6 to 14 nm, and this increase was attributed to the presence of a magnetic inert layer of 4 Å thick. Effect of particle size, concentration, and alternating magnetic field strength at 275 kHz on specific absorption rate were studied by preparing ferrofluids in deionized water at different concentrations. Ferrofluids at a concentration of 1.25 g/L, with 10 min of AMF exposure of strength ∼15.7 kA/m show stable temperatures ∼48, 58, and 68 °C with increase in the particle sizes 6, 10, and 14 nm. A maximum specific absorption rate of 251 W/g for ferrofluid with a particle size of 10 nm at 1.25 g/L, 15.7 kA/m, and 275 kHz was observed. Viability of L929 fibroblasts is measured by MTT assay cytotoxicity studies using the polyacrylic acid-coated CoFe{sub 2}O{sub 4} nanoparticles.

  10. Preparation of nanoparticles of poorly water-soluble antioxidant curcumin by antisolvent precipitation methods

    Energy Technology Data Exchange (ETDEWEB)

    Kakran, Mitali; Sahoo, Nanda Gopal; Tan, I-Lin; Li Lin, E-mail: mlli@ntu.edu.sg [Nanyang Technological University, School of Mechanical and Aerospace Engineering (Singapore)

    2012-03-15

    The objective of this study was to enhance the solubility and dissolution rate of a poorly water-soluble antioxidant, curcumin, by fabricating its nanoparticles with two methods: antisolvent precipitation with a syringe pump (APSP) and evaporative precipitation of nanosuspension (EPN). For APSP, process parameters like flow rate, stirring speed, solvent to antisolvent (SAS) ratio, and drug concentration were investigated to obtain the smallest particle size. For EPN, factors like drug concentration and the SAS ratio were examined. The effects of these process parameters on the supersaturation, nucleation, and growth rate were studied and optimized to obtain the smallest particle size of curcumin by both the methods. The average particle size of the original drug was about 10-12 {mu}m and it was decreased to a mean diameter of 330 nm for the APSP method and to 150 nm for the EPN method. Overall, decreasing the drug concentration or increasing the flow rate, stirring rate, and antisolvent amount resulted in smaller particle sizes. Differential scanning calorimetry studies suggested lower crystallinity of curcumin particles fabricated. The solubility and dissolution rates of the prepared curcumin particles were significantly higher than those the original curcumin. The antioxidant activity, studied by the DPPH free radical-scavenging assay, was greater for the curcumin nanoparticles than the original curcumin. This study demonstrated that both the methods can successfully prepare curcumin into submicro to nanoparticles. However, drug particles prepared by EPN were smaller than those by APSP and hence, showed the slightly better solubility, dissolution rate, and antioxidant activity than the latter.

  11. Reverse micelle-based water-soluble nanoparticles for simultaneous bioimaging and drug delivery.

    Science.gov (United States)

    Chen, Ying; Liu, Yong; Yao, Yongchao; Zhang, Shiyong; Gu, Zhongwei

    2017-04-11

    With special confined water pools, reverse micelles (RMs) have shown potential for a wide range of applications. However, the inherent water-insolubility of RMs hinders their further application prospects, especially for applications related to biology. We recently reported the first successful transfer of RMs from organic media to an aqueous phase without changing the smart water pools by the hydrolysis of an arm-cleavable interfacial cross-linked reverse micelles. Herein, we employed another elaborate amphiphile 1 to construct new acrylamide-based cross-linked water-soluble nanoparticles (ACW-NPs) under much gentler conditions. The special property of the water pools of the ACW-NPs was confirmed by both the Förster resonance energy transfer (FRET) between 5-((2-aminoethyl)amino)naphthalene-1-sulfonic acid (1,5-EDANS) and benzoic acid, 4-[2-[4-(dimethylamino)phenyl]diazenyl] (DABCYL) and satisfactory colloidal stability in 10% fetal bovine serum. Importantly, featured by the gentle synthetic strategy, confined water pool, and carboxylic acid-functionalized surface, the new ACW-NPs are well suitable for biological applications. As an example, the fluorescent reagent 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) was encapsulated in the core and simultaneously, the anticancer drug gemcitabine (Gem) was covalently conjugated onto the surface exterior. As expected, the resulting multifunctional ACW-NPs@HPTS@Gem exhibits a high imaging effect and anticancer activity for non-small lung cancer cells.

  12. Synthesis of robust water-soluble ZnS:Mn/SiO{sub 2} core/shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sun Jing; Zhuang Jiaqi; Guan Shaowei; Yang Wensheng [Jilin University, Key Laboratory of Surface and Interface Chemistry of Jilin Province, College of Chemistry (China)], E-mail: wsyang@jlu.edu.cn

    2008-04-15

    Water-soluble Mn doped ZnS (ZnS:Mn) nanocrystals synthesized by using 3-mercaptopropionic acid (MPA) as stabilizer were homogeneously coated with a dense silica shell through a multi-step procedure. First, 3-mercaptopropyl triethoxy silane (MPS) was used to replace MPA on the particle surface to form a vitreophilic layer for further silica deposition under optimal experimental conditions. Then a two-step silica deposition was performed to form the final water-soluble ZnS:Mn/SiO{sub 2} core/shell nanoparticles. The as-prepared core/shell nanoparticles show little change in fluorescence intensity in a wide range of pH value.

  13. Stability, cytotoxicity and cell uptake of water-soluble dendron–conjugated gold nanoparticles with 3, 12 and 17 nm cores† †Electronic supplementary information (ESI) available: Additional characterization methods and procedures in addition to the data for the characterization of glutathione-capped gold nanoparticles and dendron-conjugated gold nanoparticles including FT-IR spectra (Fig. S1 and S2), UV-vis spectra (Fig. S3 and S6), TEM images (Fig. S4), MALDI-TOF/TOF spectra (Fig. S5), fluorescence spectra (Fig. S6 and S7), In vitro cytotoxic assay results (Fig. S9) and ICP-MS results (Tables 1 and 2). DOI: 10.1039/c5tb00608b Click here for additional data file.

    Science.gov (United States)

    Deol, Suprit; Weerasuriya, Nisala

    2015-01-01

    This article describes the synthesis of water-soluble dendron–conjugated gold nanoparticles (Den–AuNPs) with various average core sizes and the evaluation of stability, cytotoxicity, cell permeability and uptake of these materials. The characterization of Den–AuNPs using various techniques including transmission electron microscopy (TEM), matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS), 1H NMR, FT-IR, and UV-vis spectroscopy confirms the dendron conjugation to the glutathione-capped gold nanoparticles (AuNPs). The stability of AuNPs and Den–AuNPs in solutions of different pH and salt concentration is determined by monitoring the changes in surface plasmon bands of gold using UV-vis spectroscopy. The stability of Den–AuNPs at different pH remained about the same compared to that of AuNPs. In comparison, the Den–AuNPs are found to be more stable than the precursor AuNPs maintaining their solubility in the aqueous solution with the salt concentration of up to 100 mM. The improved stability of Den–AuNPs suggests that the post-functionalization of thiol-capped gold nanoparticle surfaces with dendrons can further improve the physiological stability and biocompatibility of gold nanoparticle-based materials. Cytotoxicity studies of AuNPs and Den–AuNPs with and without fluorophores are also performed by examining cell viability for 3T3 fibroblasts using a MTT cell proliferation assay. The conjugation of dendrons to the AuNPs with a fluorophore is able to decrease the cytotoxicity brought about by the fluorophore. The successful uptake of Den–AuNPs in mouse fibroblast 3T3 cells shows the physiological viability of the hybrid materials. PMID:26366289

  14. Synthesis and evaluation of PEG-O-chitosan nanoparticles for delivery of poor water soluble drugs: Ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Hassani Najafabadi, Alireza [Department of Chemistry, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran (Iran, Islamic Republic of); Abdouss, Majid, E-mail: phdabdouss44@aut.ac.ir [Department of Chemistry, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran (Iran, Islamic Republic of); Faghihi, Shahab [Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161 (Iran, Islamic Republic of)

    2014-08-01

    Current methods for preparation of PEGylated chitosan have limitations such as harsh de protecting step and several purification cycles. In the present study, a facile new method for conjugating methoxy polyethylene glycol (mPEG) to chitosan under mild condition is introduced to improve water solubility of chitosan and control the release of poor water soluble drugs. The method consists of chitosan modification by grafting the C6 position of chitosan to mPEG which is confirmed by Fourier transformed-infrared (FT-IR) and proton nuclear magnetic resonance ({sup 1}HNMR) analyses. The amine groups at the C2 position of chitosan are protected using sodium dodecylsulfate (SDS) which is removed by dialyzing the precipitation against Tris solution. The chemical structure of the prepared polymer is characterized by FTIR and {sup 1}HNMR. The synthesized polymer is then employed to prepare nanoparticles which are characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and dynamic light scattering (DLS) for their size and morphology. The nanoparticles are used for encapsulation of ibuprofen followed by in vitro release investigation in gastrointestinal and simulated biological fluids. The chitosan nanoparticles are used as control. The PEGylated nanoparticles show a particle size of 80 nm with spherical morphology. The results clearly show that drug release from PEGylated chitosan nanoparticles is remarkably slower than chitosan. In addition, drug encapsulation and encapsulation efficiency in PEGylated nanoparticles are dependent on the amount of drug added to the formulation being significantly higher than chitosan nanoparticles. This study provides an efficient, novel, and facile method for preparing a nano carrier system for delivery of water insoluble drugs. - Highlights: • A facile novel method for conjugating methoxy polyethylene glycol (mPEG) to chitosan is introduced. • Fabricated PEG

  15. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  16. Synthesis of water-soluble gold clusters in nanosomes displaying robust photoluminescence with very large Stokes shift.

    Science.gov (United States)

    Santiago-González, B; Vázquez-Vázquez, C; Blanco-Varela, M C; Gaspar Martinho, J M; Ramallo-López, J M; Requejo, F G; López-Quintela, M A

    2015-10-01

    This paper reports a novel procedure using nanosomes, made of bola-hydroxyl and mercapto-palmitic acids, for the production of gold clusters with robust luminescent emissions and very large Stokes shifts. It shows that these results cannot be explained by the currently accepted mechanism based on ligand-to-metal charge transfer absorptions involving electron-rich ligands attached to the cluster core. Exhaustive characterization of the cluster samples using Mass Spectrometry, HR-TEM/STEM, XPS, EXAFS, and steady-state and time-resolved luminescence allows to deduce that a mixture of two cluster sizes, having non-closed shell electronic configurations, are firstly generated inside the nanosome compartments due to the difference in bonding strength of the two types of terminal groups in the fatty acids. This initial bimodal cluster size distribution slowly evolves into very stable, closed-shell Au cluster complexes (Au6-Au16 and Au5-Au14) responsible for the observed luminescent properties. The very small (≈1.2 nm) synthesized cluster complexes are water soluble and suitable to be used for the conjugation of biomolecules (through the terminal COO(-) groups) making these systems very attractive as biomarkers and offering, at the same time, a novel general strategy of fabricating stable atom-level quantum dots with large Stokes shifts of great importance in many sensor applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Gold Nanoparticles Cytotoxicity

    Science.gov (United States)

    Mironava, Tatsiana

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

  18. Synthesis of ZnS:Ag,Co water-soluble blue afterglow nanoparticles and application in photodynamic activation.

    Science.gov (United States)

    Ma, Lun; Zou, Xiaoju; Hossu, Marius; Chen, Wei

    2016-08-05

    Silver and cobalt co-doped ZnS (ZnS:Ag,Co) water-soluble afterglow nanoparticles were synthesized using a wet chemistry method followed by aging at room temperature. The nanoparticles had a cubic zinc blende structure with average sizes of approximately 4 nm and emitted a blue fluorescence emission centered at 441 nm due to radiative transitions from surface defects to Ag(+) luminescent centers. Intense afterglow emission peaking at 475 nm from the obtained nanoparticles was observed and was red-shifted compared to the fluorescence emission peak. X-ray photoelectron spectroscopy revealed a large increase of O/S ratio, indicating a surface oxidation process during aging. The S vacancies produced accordingly may contribute to form more electron traps and enhance afterglow. The ZnS:Ag,Co afterglow nanoparticles have a very low dark-toxicity and are applied as a light source for photodynamic therapy activation by conjugating with protoporphyrin together. Our preliminary study has shown that the ZnS:Ag,Co afterglow nanoparticles can significantly reduce the x-ray dosage used in activation and thus may be a very promising candidate for future x-ray excited photodynamic therapy in deep cancer treatment.

  19. Synthesis of ZnS:Ag,Co water-soluble blue afterglow nanoparticles and application in photodynamic activation

    Science.gov (United States)

    Ma, Lun; Zou, Xiaoju; Hossu, Marius; Chen, Wei

    2016-08-01

    Silver and cobalt co-doped ZnS (ZnS:Ag,Co) water-soluble afterglow nanoparticles were synthesized using a wet chemistry method followed by aging at room temperature. The nanoparticles had a cubic zinc blende structure with average sizes of approximately 4 nm and emitted a blue fluorescence emission centered at 441 nm due to radiative transitions from surface defects to Ag+ luminescent centers. Intense afterglow emission peaking at 475 nm from the obtained nanoparticles was observed and was red-shifted compared to the fluorescence emission peak. X-ray photoelectron spectroscopy revealed a large increase of O/S ratio, indicating a surface oxidation process during aging. The S vacancies produced accordingly may contribute to form more electron traps and enhance afterglow. The ZnS:Ag,Co afterglow nanoparticles have a very low dark-toxicity and are applied as a light source for photodynamic therapy activation by conjugating with protoporphyrin together. Our preliminary study has shown that the ZnS:Ag,Co afterglow nanoparticles can significantly reduce the x-ray dosage used in activation and thus may be a very promising candidate for future x-ray excited photodynamic therapy in deep cancer treatment.

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

    NARCIS (Netherlands)

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

    2015-01-01

    Magnetic and fluorescent hydroxyapatite nanoparticles were synthesised using Al(OH)3-stabilised MnFe2O4 or Fe3O4 nanoparticles as precursors. They were readily and efficiently radiolabelled with 18F. Bisphosphonate polyethylene glycol polymers were utilised to endow the nanoparticles with excellent

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

    Science.gov (United States)

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

    2015-06-07

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

  2. Bright, water-soluble CeF{sub 3} photo-, cathodo-, and X-ray luminescent nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Clement, Sandhya; Deng, Wei; Drozdowicz-Tomsia, Krystyna; Liu, Deming [Macquarie University, Centre for Nanoscale BioPhotonics, Department of Physics and Astronomy (Australia); Zachreson, Cameron [University of Technology Sydney, School of Physics and Advanced Materials (Australia); Goldys, Ewa M., E-mail: ewa.goldys@mq.edu.au [Macquarie University, Centre for Nanoscale BioPhotonics, Department of Physics and Astronomy (Australia)

    2015-01-15

    Bright, water-soluble CeF{sub 3} nanoparticles with small size and narrow size distribution have been synthesized using a simple co-precipitation method without any ligands. Size control of nanoparticles from 13 ± 2 to 9 ± 2 nm was achieved by varying the reaction time. Colloidal properties have been found to vary with pH and, independently, with dilution. The photoluminescence of the as-synthesized nanoparticles shows a highly photostable UV/Visible fluorescence band due to allowed 5d–4f transitions, also observed in the X-ray luminescence spectrum. This band is suitable for X-ray excitation of a range of photosensitizers. The photoluminescence quantum yield of nanoparticles was also determined to be 31 %. Using the measured fluorescence decay time of 25 ns, the radiative lifetime of Ce in CeF{sub 3} was found to be 80.6 ns. Both photoluminescence and cathodoluminescence emission are affected by the reaction time and measurement temperature. Electron-beam-induced defect annealing is also observed.

  3. Gold nanoparticle-based biosensors

    National Research Council Canada - National Science Library

    Li, Yuanyuang; Schluesener, Hermann J; Xu, Shunqing

    2010-01-01

    The unique properties of gold nanoparticles have stimulated the increasing interest in the application of GNPs in interfacing biological recognition events with signal transduction and in designing...

  4. Histidine-functionalized water-soluble nanoparticles for biomimetic nucleophilic/general-base catalysis under acidic conditions.

    Science.gov (United States)

    Chadha, Geetika; Zhao, Yan

    2013-10-21

    Cross-linking the micelles of 4-dodecyloxybenzyltripropargylammonium bromide by 1,4-diazidobutane-2,3-diol in the presence of azide-functionalized imidazole derivatives yielded surface-cross-linked micelles (SCMs) with imidazole groups on the surface. The resulting water-soluble nanoparticles were found, by fluorescence spectroscopy, to contain hydrophobic binding sites. The imidazole groups promoted the photo-deprotonation of 2-naphthol at pH 6 and catalyzed the hydrolysis of p-nitrophenylacetate (PNPA) in aqueous solution at pH ≥ 4. Although the overall hydrolysis rate slowed down with decreasing solution pH, the catalytic effect of the imidazole became stronger because the reactions catalyzed by unfunctionalized SCMs slowed down much more. The unusual ability of the imidazole–SCMs to catalyze the hydrolysis of PNPA under acidic conditions was attributed to the local hydrophobicity and the positive nature of the SCMs.

  5. Gold nanoparticles prepared using cape aloe active components.

    Science.gov (United States)

    Krpetić, Zeljka; Scarì, Giorgio; Caneva, Enrico; Speranza, Giovanna; Porta, Francesca

    2009-07-07

    A novel use of two components of Cape aloe, aloin A and aloesin, acting as stabilizers in the preparation of gold and silver nanoparticles, is reported. Stable water-soluble particles of different size and shape are prepared by varying the reaction conditions, temperature, reaction time, and reducing agents. Characterization of the obtained particles is performed using UV-visible, attenuated total reflection Fourier transform infrared (ATR-FTIR), and 1H NMR spectroscopies and transmission electron microscopy (TEM). The efficient cellular uptake of 50 nm sized aloin A and aloesin stabilized gold particles into macrophages and HeLa cells was investigated, proposing these particles as nanovehicles.

  6. Critical material attributes (CMAs) of strip films loaded with poorly water-soluble drug nanoparticles: III. Impact of drug nanoparticle loading.

    Science.gov (United States)

    Krull, Scott M; Moreno, Jacqueline; Li, Meng; Bilgili, Ecevit; Davé, Rajesh N

    2017-05-15

    Polymer strip films have emerged as a robust platform for poorly water-soluble drug delivery. However, the common conception is that films cannot exceed low drug loadings, mainly due to poor drug stability, slow release, and film brittleness. This study explores the ability to achieve high loadings of poorly water-soluble drug nanoparticles in strip films while retaining good mechanical properties and enhanced dissolution rate. Aqueous suspensions containing up to 30wt% griseofulvin nanoparticles were prepared via wet stirred media milling and incorporated into hydroxypropyl methylcellulose (HPMC) films. Griseofulvin loading in films was adjusted to be between 9 and 49wt% in HPMC-E15 films and 30 and 73wt% in HPMC-E4M films by varying the mixing ratio of HPMC solution-to-griseofulvin suspension. All films exhibited good content uniformity and nanoparticle redispersibility up to 50wt% griseofulvin, while E4M films above 50wt% griseofulvin had slightly worse content uniformity and poor nanoparticle redispersibility. Increasing drug loading in films generally required more time to achieve 100% release during dissolution, although polymer-drug clusters dispersed from E4M films above 50wt% griseofulvin, resulting in similar dissolution profiles. While all films exhibited good tensile strength, a significant decrease in percent elongation was observed above 40-50wt% GF, resulting in brittle films. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Surface modification of iron oxide nanoparticles and their conjuntion with water soluble polymers for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Thanh Huong; Lam Thi Kieu Giang; Nguyen Thanh Binh; Le Quoc Minh [Institute of Materials Science, Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam)], E-mail: nthuong@ims.vast.ac.vn

    2009-09-01

    Superparamagnetic iron oxide nanoparticles (SPION) coated with suitable bio-compatible substances have been used in biomedicine, particularly in magnetic resonance imaging (MRI), tissue engineering, and hyperthermia and drug delivery. In this study, we describe the synthesis of SPION and its surface modification for in-vitro experiments. The particle diameter and structure were estimated by FESEM, TEM, XRD analyses. The saturation magnetization was characterized. SPION with a mean size of 12 nm have been prepared under N{sub 2} atmosphere, with support of natural polymeric starch, by controlling chemical coprecipitation of magnetite phase from aqueous solutions containing suitable salts ratios of Fe{sup 2+} and Fe{sup 3+}. The surface of SPION-nanoparticles was treated with a coordinatable agent for higher dispersion ability in water and remaining the superparamagnetic behavior. The prepared iron oxide nanoparticles were coated with starch, dextran, PEG or MPEG to extend the application potential in the quite different engineering field of nano biomedicine.

  8. A novel one-pot route for the synthesis of water-soluble cadmium selenide nanoparticles

    Science.gov (United States)

    Oluwafemi, S. O.; Revaprasadu, N.; Ramirez, A. J.

    2008-06-01

    A novel, facile one-pot synthetic route to highly water dispersible and potentially biocompatible CdSe nanoparticles is reported. The monodispersed CdSe particles are passivated by cysteine, with water being the solvent. This route involves the reaction of selenium powder with sodium borohydride to produce selenide ions, followed by the addition of a cadmium salt and L-cysteine ethyl ester hydrochloride. The nanoparticles formed show quantum confinement fluorescing in the blue region. Fourier transform infrared spectroscopy study shows that CdSe nanoparticles are capped through mercapto group of the amino acid cysteine whilst its free amino and carboxylate groups make it amenable to bioconjugation establishing the possibility of using these as fluorescent biomarkers. High-resolution transmission electron spectroscopy images of these materials show well-defined, crystalline nanosized particles. Energy dispersive spectroscopy spectra confirm the presence of the corresponding elements.

  9. Forming nanoparticles of water-soluble ionic molecules and embedding them into polymer and glass substrates

    OpenAIRE

    Kiel, Stella; Grinberg, Olga; Perkas, Nina; Charmet, Jerome; Kepner, Herbert; Gedanken, Aharon

    2012-01-01

    This work describes a general method for the preparation of salt nanoparticles (NPs) made from an aqueous solution of ionic compounds (NaCl, CuSO4 and KI). These nanoparticles were created by the application of ultrasonic waves to the aqueous solutions of these salts. When the sonication was carried out in the presence of a glass microscope slide, a parylene-coated glass slide, or a silicon wafer the ionic NPs were embedded in these substrates by a one-step, ultrasound-assisted procedure. Opt...

  10. Synthesis, characterization and MRI application of magnetite water-soluble cubic nanoparticles

    Science.gov (United States)

    Nikitin, Aleksey; Fedorova, Mariia; Naumenko, Victor; Shchetinin, Igor; Abakumov, Maksim; Erofeev, Alexander; Gorelkin, Petr; Meshkov, Georgy; Beloglazkina, Elena; Ivanenkov, Yan; Klyachko, Natalya; Golovin, Yuriy; Savchenko, Alexander; Majouga, Alexander

    2017-11-01

    Magnetic nanoparticle size is one of the key factors determining its magnetic and biological properties. Herein, we report a synthesis of magnetite uniform-sized cubic nanoparticles with 10, 15 and 20 nm edge lengths for magnetic resonance imaging (MRI). The structure and physicochemical properties of obtained magnetite nanocubes (MNCbs) were studied by multiple methods. MNCbs conjugated with Pluronic F-127 exhibited high colloidal stability in aqueous medium. Synthesized MNCbs demonstrated improved T2-relaxation comparing to commercially available contrast agents proving that these nanocubes can be used for MRI.

  11. Effect of PEG and water-soluble chitosan coating on moxifloxacin-loaded PLGA long-circulating nanoparticles.

    Science.gov (United States)

    Mustafa, Sanaul; Devi, V Kusum; Pai, Roopa S

    2017-02-01

    Moxifloxacin (MOX) is a Mycobacterium tuberculosis DNA gyrase inhibitor. Due to its intense hydrophilicity, MOX is cleared from the body within 24 h and required for repetitive doses which may then result in hepatotoxicity and acquisition of MOX resistant-TB, related with its use. To overcome the aforementioned limitations, the current study aimed to develop PLGA nanoparticles (PLGA NPs), to act as an efficient carrier for controlled delivery of MOX. To achieve a substantial extension in blood circulation, a combined design, affixation of polyethylene glycol (PEG) to MOX-PLGA NPs and adsorption of water-soluble chitosan (WSC) (cationic deacetylated chitin) to particle surface, was rose for surface modification of NPs. Surface modified NPs (MOX-PEG-WSC NPs) were prepared to provide controlled delivery and circulate in the bloodstream for an extended period of time, thus minimizing dosing frequency. In vivo pharmacokinetic and in vivo biodistribution following oral administration were investigated. NP surface charge was closed to neutral +4.76 mV and significantly affected by the WSC coating. MOX-PEG-WSC NPs presented striking prolongation in blood circulation, reduced protein binding, and long-drawn-out the blood circulation half-life with resultant reduced liver sequestration vis-à-vis MOX-PLGA NPs. The studies, therefore, indicate the successful formulation development of MOX-PEG-WSC NPs that showed sustained release behavior from nanoparticles which indicates low frequency of dosing.

  12. A continuous and highly effective static mixing process for antisolvent precipitation of nanoparticles of poorly water-soluble drugs.

    Science.gov (United States)

    Dong, Yuancai; Ng, Wai Kiong; Hu, Jun; Shen, Shoucang; Tan, Reginald B H

    2010-02-15

    Rapid and homogeneous mixing of the solvent and antisolvent is critical to achieve submicron drug particles by antisolvent precipitation technique. This work aims to develop a continuous and highly effective static mixing process for antisolvent precipitation of nanoparticles of poorly water-soluble drugs with spironolactone as a model drug. Continuous antisolvent production of drug nanoparticles was carried out with a SMV DN25 static mixer comprising 6-18 mixing elements. The total flow rate ranged from 1.0 to 3.0 L/min while the flow rate ratio of solvent to antisolvent was maintained at 1:9. It is found that only 6 mixing elements were sufficient to precipitate the particles in the submicron range. Increasing the number of elements would further reduce the precipitated particle size. Increasing flow rate from 1.0 to 3.0 L/min did not further reduce the particle size, while higher drug concentrations led to particle size increase. XRD and SEM results demonstrated that the freshly precipitated drug nanoparticles are in the amorphous state, which would, in presence of the mixture of solvent and antisolvent, change to crystalline form in short time. The lyophilized spironolactone nanoparticles with lactose as lyoprotectant possessed good redispersibility and showed 6.6 and 3.3 times faster dissolution rate than that of lyophilized raw drug formulation in 5 and 10 min, respectively. The developed static mixing process exhibits high potential for continuous and large-scale antisolvent precipitation of submicron drug particles. Copyright 2009 Elsevier B.V. All rights reserved.

  13. Synthesis of silica nanoparticles for encapsulation of oncology drugs with low water solubility: effect of processing parameters on structural evolution

    Energy Technology Data Exchange (ETDEWEB)

    Bürglová, Kristýna; Hlaváč, Jan [Institute of Molecular and Translational Medicine, Palacký University Olomouc, Faculty of Medicine and Dentistry (Czech Republic); Bartlett, John R., E-mail: JBartlett@usc.edu.au [University of the Sunshine Coast, Faculty of Science, Health, Education and Engineering (Australia)

    2015-12-15

    Silica nanoparticles with tailored properties have been developed for a variety of biomedical applications, with particular emphasis on their use as carriers for the encapsulation and controlled release of bioactive species. Among the various strategies described, silica nanoparticles with uniform mesoporosity (MSN) prepared in aqueous solution at elevated temperatures using cetyltrimethylammonium bromide as a template have a range of desirable properties. However, the processing windows available to control the dimensions and other key properties of such nanoparticles prepared using fluoride salts as catalysts have not been elucidated, with mixed products containing gel fragments and non-uniform products obtained under many conditions. Here, we present a parametric study of the synthesis of MSN under fluoride-catalysed conditions using tetraethylorthosilicate as silica precursor. The processing conditions required to produce uniform nanoparticles with controlled dimensions are elucidated, together with the conditions under which dried powders can be re-dispersed in aqueous solution after long-term storage to regenerate unaggregated nanospheres with dimensions (as measured by dynamic light scattering) comparable to those measured via scanning electron microscopy analysis of the dried material. The ability to dry and store such powders for extended periods of time is an important requirement for the use of such materials in drug delivery applications. Preliminary results demonstrating the use of such MSNs as hosts for oncology drugs [substituted 3-hydroxyquinolinones (3-HQ)] with low water solubility (≪1 µg/g H{sub 2}O) are presented, with loadings of several wt% demonstrated. The ability of the silica host to protect the 3-HQ from oxidative degradation during impregnation and release is discussed.

  14. Forming nanoparticles of water-soluble ionic molecules and embedding them into polymer and glass substrates

    Directory of Open Access Journals (Sweden)

    Stella Kiel

    2012-03-01

    Full Text Available This work describes a general method for the preparation of salt nanoparticles (NPs made from an aqueous solution of ionic compounds (NaCl, CuSO4 and KI. These nanoparticles were created by the application of ultrasonic waves to the aqueous solutions of these salts. When the sonication was carried out in the presence of a glass microscope slide, a parylene-coated glass slide, or a silicon wafer the ionic NPs were embedded in these substrates by a one-step, ultrasound-assisted procedure. Optimization of the coating process resulted in homogeneous distributions of nanocrystals, 30 nm in size, on the surfaces of the substrates. The morphology and structure of each of the coatings were characterized by physical and chemical methods, such as X-ray diffraction (XRD, scanning electron microscopy (SEM, atomic force microscopy (AFM, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS. After 24 h of leaching into water the nanoparticles of the inorganic salts were still present on the slides, and complete leaching of nanoparticles occurred only after 96 h. A mechanism of the ultrasound-assisted coating is proposed.

  15. Water-soluble metal nanoparticles stabilized by plant polyphenols for improving the catalytic properties in oxidation of alcohols

    Science.gov (United States)

    Mao, H.; Liao, Y.; Ma, J.; Zhao, S. L.; Huo, F. W.

    2015-12-01

    Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic conditions, the as-prepared BWT-Pt colloid catalyst exhibited high activity in a series of biphasic oxidation of aromatic alcohols and aliphatic alcohols. As for the cycling stability, the BWT-Pt catalyst showed no obvious decrease during the 7 cycles, revealing superior cycling stability as compared with the counterparts using PVP or PEG as the stabilizer.Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic

  16. Nanoparticles of poorly water-soluble drugs prepared by supercritical fluid extraction of emulsions.

    Science.gov (United States)

    Shekunov, Boris Y; Chattopadhyay, Pratibhash; Seitzinger, Jeff; Huff, Robert

    2006-01-01

    The aim of the study was to develop and evaluate a new method for the production of micro- and nanoparticles of poorly soluble drugs for drug delivery applications. Fine particles of model compounds cholesterol acetate (CA), griseofulvin (GF), and megestrol acetate (MA) were produced by extraction of the internal phase of oil-in-water emulsions using supercritical carbon dioxide. The particles were obtained both in a batch or a continuous manner in the form of aqueous nanosuspensions. Precipitation of CA nanoparticles was used for conducting a mechanistic study on particle size control and scale-up. GF and MA nanoparticles were produced in several batches to compare their dissolution behavior with that of micronized materials. The physical analysis of the particles produced was performed using dynamic light scattering (particle size), scanning electron microscopy (morphology), powder X-ray diffraction (crystallinity), gas chromatography (residual solvent), and a dissolution apparatus. Particles with mean volume diameter ranging between 100 and 1000 nm were consistently produced. The emulsion droplet size, drug solution concentration, and organic solvent content in the emulsion were the major parameters responsible for particle size control. Efficient and fast extraction, down to low parts-per-million levels, was achieved with supercritical CO2. The GF and MA nanoparticles produced were crystalline in nature and exhibited a 5- to 10-fold increase in the dissolution rate compared with that of micronized powders. Theoretical calculations indicated that this dissolution was governed mainly by the surface kinetic coefficient and the specific surface area of the particles produced. It was observed that the necessary condition for a reliable and scalable process was the sufficient emulsion stability during the extraction time. The method developed offers a viable alternative to both the milling and constructive nanoparticle formation processes. Although preparation of a

  17. Directed Assembly of Gold Nanoparticles

    DEFF Research Database (Denmark)

    Westerlund, Axel Rune Fredrik; Bjørnholm, Thomas

    2009-01-01

    As a complement to common "top-down" lithography techniques, "bottom-up" assembly techniques are emerging as promising tools to build nanoscale structures in a predictable way. Gold nanoparticles that are stable and relatively easy to synthesize are important building blocks in many such structures...... due to their useful optical and electronic properties. Programmed assembly of gold nanoparticles in one, two, and three dimensions is therefore of large interest. This review focuses on the progress from the last three years in the field of directed gold nanoparticle and nanorod assembly using...

  18. Controlled Synthesis of Water-Soluble NaYF4:Yb3+, Er3+ Nanoparticles with Surfactant Dependent Properties

    Directory of Open Access Journals (Sweden)

    Junwei Zhao

    2014-01-01

    Full Text Available Water-soluble NaYF4:Yb3+, Er3+ nanoparticles (NPs are successfully prepared by a solvothermal reaction using branched polyethylenimine (PEI with different chain lengths as the surfactants in a water/diethylene glycol (DEG mixed solution. It is shown that the size of NaYF4 NPs prepared with high molecular weight PEI (HPEI is smaller than that of the NPs prepared with low molecular weight (LPEI, while small-sized NPs exhibit more intense upconversion luminescence intensities than large-sized NPs in the same excitation power of 980 nm. It is found that HPEI is conducive to the formation of smaller NP with high crystallinity. Small-sized NaYF4:Yb3+, Er3+ NPs with intense upconversion luminescence and improved crystallinity were related to their growth process. A possible growth mechanism of the samples is proposed. The results of this study can provide new insights into the controlled synthesis of novel NPs.

  19. Development of Lipid-Shell and Polymer Core Nanoparticles with Water-Soluble Salidroside for Anti-Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Dai-Long Fang

    2014-02-01

    Full Text Available Salidroside (Sal is a potent antitumor drug with high water-solubility. The clinic application of Sal in cancer therapy has been significantly restricted by poor oral absorption and low tumor cell uptake. To solve this problem, lipid-shell and polymer-core nanoparticles (Sal-LPNPs loaded with Sal were developed by a double emulsification method. The processing parameters including the polymer types, organic phase, PVA types and amount were systemically investigated. The obtained optimal Sal-LPNPs, composed of PLGA-PEG-PLGA triblock copolymers and lipids, had high entrapment efficiency (65%, submicron size (150 nm and negatively charged surface (−23 mV. DSC analysis demonstrated the successful encapsulation of Sal into LPNPs. The core-shell structure of Sal-LPNPs was verified by TEM. Sal released slowly from the LPNPs without apparent burst release. MTT assay revealed that 4T1 and PANC-1 cancer cell lines were sensitive to Sal treatment. Sal-LPNPs had significantly higher antitumor activities than free Sal in 4T1 and PANC-1 cells. The data indicate that LPNPs are a promising Sal vehicle for anti-cancer therapy and worthy of further investigation.

  20. Development of Lipid-Shell and Polymer Core Nanoparticles with Water-Soluble Salidroside for Anti-Cancer Therapy

    Science.gov (United States)

    Fang, Dai-Long; Chen, Yan; Xu, Bei; Ren, Ke; He, Zhi-Yao; He, Li-Li; Lei, Yi; Fan, Chun-Mei; Song, Xiang-Rong

    2014-01-01

    Salidroside (Sal) is a potent antitumor drug with high water-solubility. The clinic application of Sal in cancer therapy has been significantly restricted by poor oral absorption and low tumor cell uptake. To solve this problem, lipid-shell and polymer-core nanoparticles (Sal-LPNPs) loaded with Sal were developed by a double emulsification method. The processing parameters including the polymer types, organic phase, PVA types and amount were systemically investigated. The obtained optimal Sal-LPNPs, composed of PLGA-PEG-PLGA triblock copolymers and lipids, had high entrapment efficiency (65%), submicron size (150 nm) and negatively charged surface (−23 mV). DSC analysis demonstrated the successful encapsulation of Sal into LPNPs. The core-shell structure of Sal-LPNPs was verified by TEM. Sal released slowly from the LPNPs without apparent burst release. MTT assay revealed that 4T1 and PANC-1 cancer cell lines were sensitive to Sal treatment. Sal-LPNPs had significantly higher antitumor activities than free Sal in 4T1 and PANC-1 cells. The data indicate that LPNPs are a promising Sal vehicle for anti-cancer therapy and worthy of further investigation. PMID:24573250

  1. Highly water soluble nanoparticles as a draw solute in forward osmosis for the treatment of radioactive liquid waste

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Heeman; Choi, Hye Min; Jang, Sungchan; Seo, Bumkyoung; Lee, Kune Woo; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    . In this study, we introduced highly water-soluble hyperbranched caroboxylated polyglycerol-coated magnetic nanoparticles (CPG-MNPs). It is known that the highly branched, globular architecture of PG significantly increase solubility compared to linear polymer and they are eco-friendly. The CPG-MNPs showed no aggregate of particles in water even after placing external magnet, and exhibited a high water flux in FO process. The CPG-MNPs are, therefore, potentially useful as a draw solute in FO processes. The operation of nuclear pressurized water reactors (PWRs) results in numerous radioactive waste streams which vary in radioactivity content. Most PWR stations have experienced leakages of boric acid into liquid radioactive waste systems. These wastes contain about 0.3∼0.8 wt% of boric acid. It is known that reverse osmosis (RO) membrane can eliminate boron at high pH and boron of 40∼90% can be removed by RO membrane in pH condition. RO uses hydraulic pressure to oppose, and exceed, the osmotic pressure of an aqueous feed solution containing boric acid. Forward osmosis (FO), a low energy technique based on membrane technologies, has recently garnered attention for its utility in wastewater treatment and desalination applications. In the FO process, water flows across a semi-permeable membrane from a solution with a low osmotic pressure (the feed solution) to a solution with a high osmotic pressure (the draw solution). The driving force in FO processes is provided by the osmotic gradient between the two solutions. Low energy costs and low degrees of membrane fouling are two of the advantages conveyed by FO processes over other processes, such as reverse osmosis processes that rely on a hydraulic pressure driving force. However, the challenges of FO still lie in the fabrication of eligible FO membranes and the readily separable draw solutes of high osmotic pressures. Superparamagnetic Fe3O4 nanoparticles can be separated from water by an external magnet field

  2. Synthesis and Characterization of Gold Nanoparticles

    OpenAIRE

    Hedkvist, Olof

    2013-01-01

    This thesis is focused on the synthesis of three different shapes of gold nanoparticles; the gold nanosphere, the gold nanorod and the gold nanocube. These will be synthesized using wet chemistry methods and characterized using UV-Vis- NIR spectroscopy and dynamic light scattering. The results will be used to draw some conclusions as to what factors influence the growth of gold nanoparticles.

  3. L-Leucine for gold nanoparticles synthesis and their cytotoxic effects evaluation.

    Science.gov (United States)

    Berghian-Grosan, Camelia; Olenic, Liliana; Katona, Gabriel; Perde-Schrepler, Maria; Vulcu, Adriana

    2014-11-01

    This work reports the preparation of water-soluble leucine capped gold nanoparticles by two single-step synthesis methods. The first procedure involves a citrate reduction approach where the citrate is used as reducing agent and leucine as capping/stabilizing agent. Different sizes of gold nanoparticles, citrate reduced and stabilized by leucine, Leu-AuNPs-C, with the mean diameters in the range of 21-56 nm, were obtained by varying the macroscopic parameters such as: concentration of the gold precursor solution, Au (III):citrate molar ratio and leucine pH. In the second procedure, leucine acts both as reducing and stabilizing agent, allowing us to obtain spherical gold nanoparticles, Leu-AuNPs, with a majority of 80 % (with the mean diameter of 63 nm). This proves that leucine is an appropriate reductant for the formation of water-soluble and stable gold nanoparticles colloids. The characterization of the leucine coated gold nanoparticles was carried out by TEM, UV-Vis and FT-IR analysis. The cytotoxic effect of Leu-AuNPs-C and Leu-AuNPs was also evaluated.

  4. Application of hydrophobically modified water-soluble polymers for the dispersion of hydrophobic magnetic nanoparticles in aqueous media.

    Science.gov (United States)

    Iatridi, Zacharoula; Georgiadou, Violetta; Menelaou, Melita; Dendrinou-Samara, Catherine; Bokias, Georgios

    2014-06-21

    Hydrophobically modified water-soluble polymers (HMWSPs), comprised of a poly(sodium methacrylate) (PMANa) or poly(sodium acrylate) (PANa) backbone and pendent dodecyl methacrylate (DMA) or dodecyl acrylamide (DAAm) chains, respectively, were synthesized. The hydrophobic content of the copolymers, P(MANa-co-DMA) and P(ANa-co-DAAm), is in the range of 0 to 25 mol%, while their weight-average molar mass varies from ~10 000 up to ~75 000. Their self-assembly behavior in dilute aqueous solution was followed through Nile Red probing, DLS and TEM measurements. The critical micelle concentration (CMC) is mainly controlled by the hydrophobic content and not the molar mass of the copolymers. Above CMC, spherical and large-compound micelles are identified by DLS and TEM. Moreover, oleylamine coated CoFe2O4 nanoparticles (CoFe2O4@OAm MNPs) of 9.4 nm with a saturation magnetization Ms = 85 emu g(-1) were solvothermally prepared. The hydrophobic CoFe2O4@OAm MNPs were successfully encapsulated into the hydrophobic cores of the structures formed by the copolymers above CMC through a solvent mixing procedure, and in that way hydrophilic CoFe2O4@HMWSP nanohybrids resulted. For comparison purposes, two alternate phase transfer approaches were also used to convert CoFe2O4@OAm MNPs to hydrophilic ones: (a) addition of a coating layer by cetyltrimethyl ammonium bromide (CTAB) and (b) by the ligand exchange procedure with 2,3-dimercaptosuccinic acid (DMSA). NMR transverse relaxivity measurements of the aqueous suspensions of CoFe2O4@P(ANa-co-DAAm), CoFe2O4@CTAB and CoFe2O4@DMSA were recorded and the r2 relaxivity was determined. CoFe2O4@CTAB demonstrated the highest r2 relaxivity of 554.0 mM(-1) s(-1), while CoFe2O4@P(ANa-co-DAAm) and CoFe2O4@DMSA showed lower values of 313.6 mM(-1) s(-1) and 76.3 mM(-1) s(-1), respectively.

  5. A Novel Strategy for Synthesis of Gold Nanoparticle Self Assemblies

    NARCIS (Netherlands)

    Verma, Jyoti; Lal, Sumit; van Veen, Henk A.; van Noorden, Cornelis J. F.

    2014-01-01

    Gold nanoparticle self assemblies are one-dimensional structures of gold nanoparticles. Gold nanoparticle self assemblies exhibit unique physical properties and find applications in the development of biosensors. Methodologies currently available for lab-scale and commercial synthesis of gold

  6. Fungus-mediated preferential bioleaching of waste material such as fly - ash as a means of producing extracellular, protein capped, fluorescent and water soluble silica nanoparticles.

    Directory of Open Access Journals (Sweden)

    Shadab Ali Khan

    Full Text Available In this paper, we for the first time show the ability of the mesophilic fungus Fusarium oxysporum in the bioleaching of waste material such as Fly-ash for the extracellular production of highly crystalline and highly stable, protein capped, fluorescent and water soluble silica nanoparticles at ambient conditions. When the fungus Fusarium oxysporum is exposed to Fly-ash, it is capable of selectively leaching out silica nanoparticles of quasi-spherical morphology within 24 h of reaction. These silica nanoparticles have been completely characterized by UV-vis spectroscopy, Photoluminescence (PL, Transmission electron microscopy (TEM, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and Energy dispersive analysis of X-rays (EDAX.

  7. Polycations-functionalized water-soluble gold nanoclusters: a potential platform for simultaneous enhanced gene delivery and cell imaging

    Science.gov (United States)

    Tao, Yu; Li, Zhenhua; Ju, Enguo; Ren, Jinsong; Qu, Xiaogang

    2013-06-01

    Noble metal nanoclusters have emerged as a fascinating area of widespread interest in nanomaterials. Herein, we report the synthesis of the PEI-templated gold nanoclusters (PEI-AuNCs) as an efficient carrier for gene delivery. The PEI-AuNCs integrate the advantages of PEI and AuNCs: the presence of AuNCs can effectively decrease the cytotoxicity of PEI, making it possible to apply them in biological systems, while the cationic polymer layer PEI with positive charges is essential for enhanced gene transfection efficiency. In addition, with excellent photoluminescent properties, the AuNCs also endow our system with the versatility of fluorescent imaging, indicating a great potential as an ideal fluorescent probe to track the transfection behavior. Our studies provide strong evidence that the PEI-AuNCs can be utilized as efficient gene delivery agents.Noble metal nanoclusters have emerged as a fascinating area of widespread interest in nanomaterials. Herein, we report the synthesis of the PEI-templated gold nanoclusters (PEI-AuNCs) as an efficient carrier for gene delivery. The PEI-AuNCs integrate the advantages of PEI and AuNCs: the presence of AuNCs can effectively decrease the cytotoxicity of PEI, making it possible to apply them in biological systems, while the cationic polymer layer PEI with positive charges is essential for enhanced gene transfection efficiency. In addition, with excellent photoluminescent properties, the AuNCs also endow our system with the versatility of fluorescent imaging, indicating a great potential as an ideal fluorescent probe to track the transfection behavior. Our studies provide strong evidence that the PEI-AuNCs can be utilized as efficient gene delivery agents. Electronic supplementary information (ESI) available: Supporting figures. See DOI: 10.1039/c3nr01326j

  8. Iron oxide and gold nanoparticles in cancer therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gotman, Irena, E-mail: gotman@technion.ac.il; Gutmanas, Elazar Y., E-mail: gutmanas@technion.ac.il [Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, 32000 Israel (Israel); Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Psakhie, Sergey G. [Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Lozhkomoev, Aleksandr S. [Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2016-08-02

    Continuous research activities in the field of nanomedicine in the past decade have, to a great extent, been focused on nanoparticle technologies for cancer therapy. Gold and iron oxide nanoparticles (NP) are two of the most studied inorganic nanomaterials due to their unique optical and magnetic properties. Both types of NPs are emerging as promising systems for anti-tumor drug delivery and for nanoparticle-mediated thermal therapy of cancer. In thermal therapy, localized heating inside tumors or in proximity of tumor cells can be induced, for example, with Au NPs by radiofrequency ablation heating or conversion of photon energy (photothermal therapy) and in iron oxide magnetic NPs by heat generation through relaxation in an alternating magnetic field (magnetic hyperthermia). Furthermore, the superparamagnetic properties of iron oxide nanoparticles have led to their use as potent MRI (magnetic resonance imaging) contrast agents. Surface modification/coating can produce NPs with tailored and desired properties, such as enhanced blood circulation time, stability, biocompatibility and water solubility. To target nanoparticles to specific tumor cells, NPs should be conjugated with targeting moieties on the surface which bind to receptors or other molecular structures on the cell surface. The article presents several approaches to enhancing the specificity of Au and iron oxide nanoparticles for tumor tissue by appropriate surface modification/functionalization, as well as the effect of these treatments on the saturation magnetization value of iron oxide NPs. The use of other nanoparticles and nanostructures in cancer treatment is also briefly reviewed.

  9. Application of Gold Nanoparticles to Paint Colorants

    Science.gov (United States)

    Ishibashi, Hideo

    Metal nanoparticles possess unique properties that they do not exhibit in their bulk states. One of these properties is the color due to surface plasmon resonance. Gold nanoparticles appear red. This color has been utilized in glass for a long long time. In recent years, highly concentrated pastes of gold and silver nanoparticles have been successfully produced by using a special type of protective polymer and a mild reductant. The paste of gold nanoparticles can be used for paint and other materials as red colorants. In this article,application examples of gold nanoparticles as colorant are introduced. Recently, methods for producing bimetal nanoparticles such as gold/silver and gold/copper have been developed. These nanoparticles allow colors from yellow to green to be created. These methods and colors they produce are also described in this article.

  10. Lamellar multilayer hexadecylaniline-modified gold nanoparticle ...

    Indian Academy of Sciences (India)

    Abstract. Organization of hexadecylaniline (HDA)-modified colloidal gold particles at the air–water interface and the formation thereafter of lamellar, multilayer films of gold nanoparticles by the Langmuir–Blodgett technique is described in this paper. Formation of HDA-capped gold nanoparticles is accomplished by a simple.

  11. Lamellar multilayer hexadecylaniline-modified gold nanoparticle ...

    Indian Academy of Sciences (India)

    Organization of hexadecylaniline (HDA)-modified colloidal gold particles at the air-water interface and the formation thereafter of lamellar, multilayer films of gold nanoparticles by the Langmuir-Blodgett technique is described in this paper. Formation of HDA-capped gold nanoparticles is accomplished by a simple biphasic ...

  12. Water-Soluble Chitosan Nanoparticles Inhibit Hypercholesterolemia Induced by Feeding a High-Fat Diet in Male Sprague-Dawley Rats

    Directory of Open Access Journals (Sweden)

    Yi Tao

    2011-01-01

    Full Text Available Chitosan, a deacetylated product of chitin, has been demonstrated to lower cholesterol in humans and animals. However, chitosan is not fully soluble in water which would influence absorption in the human intestine. In addition, water-soluble chitosan (WSC has higher reactivity compared to chitosan. The present study was designed to clarify the effects of WSC and water-soluble chitosan nanoparticles (WSC-NPs on hypercholesterolemia induced by feeding a high-fat diet in male Sprague-Dawley rats. WSC-NPs were prepared by the ionic gelation method and the spray-drying technique. The nanoparticles were spherical in shape and had a smooth surface. The mean size of WSC-NPs was 650 nm variing from 500 to 800 nm. Results showed that WSC-NPs reduced the blood lipids and plasma viscosity significantly and increased the serum superoxide dismutase (SOD activities significantly. This paper is the first report of the lipid-lowering effects of WSC-NPs suggesting that the WSC-NPs could be used for the treatment of hypercholesterolemia.

  13. Poly-L-lysine-modified reduced graphene oxide stabilizes the copper nanoparticles with higher water-solubility and long-term additively antibacterial activity.

    Science.gov (United States)

    Ouyang, Yu; Cai, Xiang; Shi, QingShan; Liu, Lili; Wan, Dongliang; Tan, Shaozao; Ouyang, Yousheng

    2013-07-01

    In order to improve the water-solubility and long-term antibacterial activity of copper nanoparticles (CuNPs), a poly-L-lysine-modified reduced graphene oxide (PLL-rGO) was used as the carrier of CuNPs, and a poly-L-lysine/reduced graphene oxide/copper nanoparticles (PLL-rGO-CuNPs) hybrid was prepared by anchoring the CuNPs on the reduced graphene oxide surface. The novel PLL-rGO-CuNPs hybrid was characterized and the antibacterial activity of it on gram-negative Escherichia coli and Gram-positive Staphylococcus aureus was tested. Such a hybrid showed additively antibacterial activity, and the CuNPs on PLL-rGO were more stable than those on polyvinyl pyrrolidone, resulting in long-term additively antibacterial effect. Meanwhile, this hybrid showed excellent water-solubility, suggesting great potential application in microbial control. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  14. Preparation of gold nanoparticle dimers via streptavidin-induced interlinking

    Energy Technology Data Exchange (ETDEWEB)

    Zon, Vera B.; Sachsenhauser, Matthias; Rant, Ulrich, E-mail: rant@wsi.tum.de [Technische Universitaet Muenchen, Walter Schottky Institut (Germany)

    2013-10-15

    There is great interest in establishing efficient means of organizing nanoparticles into complex structures, especially in fields like nano-optical devices. One of the demonstrated routes uses biomolecular scaffolds, like the streptavidin-biotin system, to deterministically separate and structure particle complexes. However, controlled formation of streptavidin-linked nanoparticle dimers or trimers is challenging, and large aggregates are often formed under conditions that are difficult to regulate. Here, we studied the aggregates and interlinking kinetics of biotin-functionalized 20 nm gold nanoparticles in the presence of the interlinking protein, streptavidin. We found two different protein-linker concentration regions where small stable particle aggregates are formed: when the protein and nanoparticle concentrations are similar and when the protein to nanoparticle concentration ratio exceeds intermediate concentrations (10:1-100:1) that promote precipitation of large aggregates. We attribute this behavior to the limited availability of free-linker molecules and the limited availability of free ligand (biotin) on the particle surface for low and high protein concentrations, respectively. Furthermore, we show that the product can be additionally enriched up to 25 % through either centrifugation in sucrose or size-exclusion chromatography. These results provide additional understanding into the assembly of ligand-functionalized nanoparticles with water-soluble linkers and provide a facile way to produce well-defined small aggregates for potential use in, for instance, surface-enhanced spectroscopy.

  15. Gold nanoparticle assisted assembly of a heme protein for enhancement of long-range interfacial electron transfer

    DEFF Research Database (Denmark)

    Jensen, Palle Skovhus; Chi, Qijin; Grumsen, Flemming Bjerg

    2007-01-01

    -defined stoichiometry. The systems were investigated in homogeneous solution and at liquid/solid interface. Conjugation of cyt c results in a small but consistent broadening of the nanoparticle plasmon band. This phenomenon can be explained in terms of long-range electronic interactions between the gold nanoparticle...... and characterization of water-soluble gold nanoparticles (AuNPs) with core diameter 3-4 nm and their application for the enhancement of long-range interfacial ET of a heme protein. Gold nanoparticles were electrostatically conjugated with cyt c to form nanoparticle-protein hybrid ET systems with well...... and the protein molecule. When the nanoparticle-protein conjugates are assembled on Au(111) surfaces, long-range interfacial ET across a physical distance of over 50 A via the nanoparticle becomes feasible. Moreover, significant enhancement of the interfacial ET rate by more than an order of magnitude compared...

  16. Gold Nanoparticle Mediated Phototherapy for Cancer

    Directory of Open Access Journals (Sweden)

    Cuiping Yao

    2016-01-01

    Full Text Available Gold nanoparticles exhibit very unique physiochemical and optical properties, which now are extensively studied in range of medical diagnostic and therapeutic applications. In particular, gold nanoparticles show promise in the advancement of cancer treatments. This review will provide insights into the four different cancer treatments such as photothermal therapy, gold nanoparticle-aided photodynamic therapy, gold nanoparticle-aided radiation therapy, and their use as drug carrier. We also discuss the mechanism of every method and the adverse effects and its limitations.

  17. Critical material attributes (CMAs) of strip films loaded with poorly water-soluble drug nanoparticles: I. Impact of plasticizer on film properties and dissolution.

    Science.gov (United States)

    Krull, Scott M; Patel, Hardik V; Li, Meng; Bilgili, Ecevit; Davé, Rajesh N

    2016-09-20

    Recent studies have demonstrated polymer films to be a promising platform for delivery of poorly water-soluble drug particles. However, the impact of critical material attributes, for example plasticizer, on the properties of and drug release from such films has yet to be investigated. In response, this study focuses on the impact of plasticizer and plasticizer concentration on properties and dissolution rate of polymer films loaded with poorly water-soluble drug nanoparticles. Glycerin, triacetin, and polyethylene glycol were selected as film plasticizers. Griseofulvin was used as a model Biopharmaceutics Classification System class II drug and hydroxypropyl methylcellulose was used as a film-forming polymer. Griseofulvin nanoparticles were prepared via wet stirred media milling in aqueous suspension. A depression in film glass transition temperature was observed with increasing plasticizer concentration, along with a decrease in film tensile strength and an increase in film elongation, as is typical of plasticizers. However, the type and amount of plasticizer necessary to produce strong yet flexible films had no significant impact on the dissolution rate of the films, suggesting that film mechanical properties can be effectively manipulated with minimal impact on drug release. Griseofulvin nanoparticles were successfully recovered upon redispersion in water regardless of plasticizer or content, even after up to 6months' storage at 40°C and 75% relative humidity, which contributed to similar consistency in dissolution rate after 6months' storage for all films. Good content uniformity (<4% R.S.D. for very small film sample size) was also maintained across all film formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. One-pot synthesis of water-soluble superparamagnetic iron oxide nanoparticles and their MRI contrast effects in the mouse brains.

    Science.gov (United States)

    Wang, Jun; Zhang, Baolin; Wang, Lei; Wang, Ming; Gao, Fabao

    2015-03-01

    Water-soluble superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by the thermal decomposition of iron (III) acetylacetonate (Fe(acac)3) in the mixture of poly(ethylene glycol) (PEG) and poly(ethylene imine) (PEI). The average sizes of the SPIONs are in the range of 6-12nm, which could be tuned by adjusting the synthesis temperature and molecular weight of PEI. Benefiting from the coating of hydrophilic PEG and PEI, the resulted SPIONs showed excellent colloidal stability in deionized water and other physiological buffers. The XRD patterns indicate that the obtained SPIONs are magnetite. The PEG/PEI-SPIONs exhibited high r2/r1 ratio. In vivo magnetic resonance imaging (MRI) of the mouse brains after intravenous injection of the SPIONs showed their good contrast effect. Considering the facile fabrication process and excellent imaging performance of the water soluble PEG-SPIONs and PEG/PEI-SPIONs, it is believed that the SPIONs will find great potential in advanced MRI. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Biosynthesis of gold nanoparticles using diatoms—silica-gold and EPS-gold bionanocomposite formation

    Science.gov (United States)

    Schröfel, Adam; Kratošová, Gabriela; Bohunická, Markéta; Dobročka, Edmund; Vávra, Ivo

    2011-08-01

    Novel synthesis of gold nanoparticles, EPS-gold, and silica-gold bionanocomposites by biologically driven processes employing two diatom strains ( Navicula atomus, Diadesmis gallica) is described. Transmission electron microscopy (TEM) and electron diffraction analysis (SAED) revealed a presence of gold nanoparticles in the experimental solutions of the diatom culture mixed with tetrachloroaureate. Nature of the gold nanoparticles was confirmed by X-ray diffraction studies. Scanning electron microscopy (SEM) and TEM showed that the nanoparticles were associated with the diatom frustules and extracellular polysaccharides (EPS) excreted by the diatom cells. Due to its accessibility, simplicity, and effectiveness, this method of nanocomposites preparation has great importance for possible future applications.

  20. Improved luminescence in water-soluble hollow LaF3:Eu3+ nanoparticles by introducing Li+ ions

    Science.gov (United States)

    Fan, Ting; Lü, Jiantao; Lin, Futian; Zhou, Zifan

    2016-04-01

    Improved red emission in polyvinylpyrrolidone (PVP)-coated hollow LaF3:Eu3+ nanoparticles by introducing Li+ ions was found for the first time via a one-step template-free hydrothermal method. The hollow formation can be attributed to self-recrystallization and a local Ostwald ripening thermodynamic process. Pores were clearly seen and widely distributed in all LaF3 nanoparticles. The introduction of Li+ ions did not introduce new crystalline phases and resulted in little change in size and morphology of the LaF3 nanoparticles. The main diffraction peaks were found to shift slightly with the Li+ doping concentrations, which indicates that Li+ changes the crystal field environment of Eu3+. The excitation and red emission intensity both doubled when codoped with 7 mol% Li+ ions. The widely distributed pores and improved luminescence properties of our nanoparticles facilitated the construction of new nanocomposites for novel biological applications.

  1. Gravitational sedimentation of gold nanoparticles.

    Science.gov (United States)

    Alexander, Colleen M; Dabrowiak, James C; Goodisman, Jerry

    2013-04-15

    We study the gravitational sedimentation of citrate- or ascorbate-capped spherical gold nanoparticles (AuNP) by measuring the absorption-vs.-time curve produced as the particles sediment through the optical beam of a spectrophotometer, and comparing the results with a calculated sedimentation curve. TEM showed the AuNP had gold-core diameters of 12.1±0.6, 65.0±5.2, 82.5±5.2 or 91.8±6.2 nm, and gave diameter distribution histograms. The Mason-Weaver sedimentation-diffusion equation was solved for various particle diameters and the solutions were weighted with the TEM histogram and the size-dependent extinction coefficient, for comparison with absorbance-vs.-time curve obtained from freshly prepared suspensions of the AuNP. For particles having average gold-core diameters of 12.1±0.6, 65.0±5.2 and 82.5±5.2 nm, very good agreement exists between the theoretical and observed curves, showing that the particles sediment individually and that the diameter of the gold core is the important factor controlling sedimentation. For the largest particles, observed and calculated curves generally agree, but the former shows random effects consistent with non-homogeneous domains in the sample. Unlike TEM, the simple and unambiguous sedimentation experiment detects all the particles in the sample and can in principle be used to derive the true size histogram. It avoids artifacts of TEM sampling and shear forces of ultracentrifugation. We also show how information about the size histogram can be obtained from the sedimentation curve. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Chrysopogon zizanioides aqueous extract mediated synthesis, characterization of crystalline silver and gold nanoparticles for biomedical applications.

    Science.gov (United States)

    Arunachalam, Kantha D; Annamalai, Sathesh Kumar

    2013-01-01

    The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The aim of this study was to develop a simple biological method for the synthesis of silver and gold nanoparticles using Chrysopogon zizanioides. To exploit various plant materials for the biosynthesis of nanoparticles was considered a green technology. An aqueous leaf extract of C. zizanioides was used to synthesize silver and gold nanoparticles by the bioreduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) respectively. Water-soluble organics present in the plant materials were mainly responsible for reducing silver or gold ions to nanosized Ag or Au particles. The synthesized silver and gold nanoparticles were characterized by ultraviolet (UV)-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. The kinetics decline reactions of aqueous silver/gold ion with the C. zizanioides crude extract were determined by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to the extract were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20-50 nm. This eco-friendly approach for the synthesis of nanoparticles is simple, can be scaled up for large-scale production with powerful bioactivity as demonstrated by the synthesized silver nanoparticles. The synthesized nanoparticles can have clinical use as antibacterial, antioxidant, as well as cytotoxic agents and can be used for biomedical applications.

  3. Chrysopogon zizanioides aqueous extract mediated synthesis, characterization of crystalline silver and gold nanoparticles for biomedical applications

    Science.gov (United States)

    Arunachalam, Kantha D; Annamalai, Sathesh Kumar

    2013-01-01

    The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The aim of this study was to develop a simple biological method for the synthesis of silver and gold nanoparticles using Chrysopogon zizanioides. To exploit various plant materials for the biosynthesis of nanoparticles was considered a green technology. An aqueous leaf extract of C. zizanioides was used to synthesize silver and gold nanoparticles by the bioreduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) respectively. Water-soluble organics present in the plant materials were mainly responsible for reducing silver or gold ions to nanosized Ag or Au particles. The synthesized silver and gold nanoparticles were characterized by ultraviolet (UV)-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. The kinetics decline reactions of aqueous silver/gold ion with the C. zizanioides crude extract were determined by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to the extract were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20–50 nm. This eco-friendly approach for the synthesis of nanoparticles is simple, can be scaled up for large-scale production with powerful bioactivity as demonstrated by the synthesized silver nanoparticles. The synthesized nanoparticles can have clinical use as antibacterial, antioxidant, as well as cytotoxic agents and can be used for biomedical applications. PMID:23861583

  4. Functional Gold Nanoparticles for Biomedical Applications

    OpenAIRE

    Hühn, Dominik

    2014-01-01

    Abstract Subjects of the present dissertation are the synthesis, the functionalization and the characterization of colloidal gold nanoparticles. The employed nanoparticles consist of an inorganic Au core of approximately 5 nm diameter, which is stabilized by hydrophobic surface molecules. To transfer the nanoparticles to aqueous environments (an indispensable necessity for biomedical applications) they are coated with an amphiphil...

  5. Lipoic Acid Gold Nanoparticles Functionalized with Organic Compounds as Bioactive Materials.

    Science.gov (United States)

    Turcu, Ioana; Zarafu, Irina; Popa, Marcela; Chifiriuc, Mariana Carmen; Bleotu, Coralia; Culita, Daniela; Ghica, Corneliu; Ionita, Petre

    2017-02-16

    Water soluble gold nanoparticles protected by lipoic acid were obtained and further functionalized by standard coupling reaction with 1-naphtylamine, 4-aminoantipyrine, and 4'-aminobenzo-15-crown-5 ether. Derivatives of lipoic acid with 1-naphtylamine, 4-aminoantipyrine, and 4'-aminobenzo-15-crown-5 ether were also obtained and characterized. All these were tested for their antimicrobial activity, as well as for their influence on mammalian cell viability and cellular cycle. In all cases a decreased antimicrobial activity of the obtained bioactive nanoparticles was observed as compared with the organic compounds, proving that a possible inactivation of the bioactive groups could occur during functionalization. However, both the gold nanoparticles as well as the functionalized bioactive nanosystems proved to be biocompatible at concentrations lower than 50 µg/mL, as revealed by the cellular viability and cell cycle assay, demonstrating their potential for the development of novel antimicrobial agents.

  6. Lipoic Acid Gold Nanoparticles Functionalized with Organic Compounds as Bioactive Materials

    Directory of Open Access Journals (Sweden)

    Ioana Turcu

    2017-02-01

    Full Text Available Water soluble gold nanoparticles protected by lipoic acid were obtained and further functionalized by standard coupling reaction with 1-naphtylamine, 4-aminoantipyrine, and 4′-aminobenzo-15-crown-5 ether. Derivatives of lipoic acid with 1-naphtylamine, 4-aminoantipyrine, and 4′-aminobenzo-15-crown-5 ether were also obtained and characterized. All these were tested for their antimicrobial activity, as well as for their influence on mammalian cell viability and cellular cycle. In all cases a decreased antimicrobial activity of the obtained bioactive nanoparticles was observed as compared with the organic compounds, proving that a possible inactivation of the bioactive groups could occur during functionalization. However, both the gold nanoparticles as well as the functionalized bioactive nanosystems proved to be biocompatible at concentrations lower than 50 µg/mL, as revealed by the cellular viability and cell cycle assay, demonstrating their potential for the development of novel antimicrobial agents.

  7. Gold nanoparticles produced in a microalga

    Science.gov (United States)

    Luangpipat, Tiyaporn; Beattie, Isabel R.; Chisti, Yusuf; Haverkamp, Richard G.

    2011-12-01

    An efficient biological route to production of gold nanoparticles which allows the nanoparticles to be easily recovered remains elusive. Live cells of the green microalga Chlorella vulgaris were incubated with a solution of gold chloride and harvested by centrifugation. Nanoparticles inside intact cells were identified by transmission electron microscopy and confirmed to be metallic gold by synchrotron based X-ray powder diffraction and X-ray absorption spectroscopy. These intracellular gold nanoparticles were 40-60 nm in diameter. At a concentration of 1.4% Au in the alga, a better than 97% recovery of the gold from solution was achieved. A maximum of 4.2% Au in the alga was obtained. Exposure of C. vulgaris to solutions containing dissolved salts of palladium, ruthenium, and rhodium also resulted in the production of the corresponding nanoparticles within the cells. These were surmised to be also metallic, but were produced at a much lower intracellular concentration than achieved with gold. Iridium was apparently toxic to the alga. No nanoparticles were observed using platinum solutions. C. vulgaris provides a possible route to large scale production of gold nanoparticles.

  8. CO oxidation on gold nanoparticles: Theoretical studies

    DEFF Research Database (Denmark)

    Remediakis, Ioannis; Lopez, Nuria; Nørskov, Jens Kehlet

    2005-01-01

    We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold...... nanoparticles can adsorb small inorganic molecules such as O2 and CO, and the presence of these sites is the key factor for the catalytic properties of supported gold nanoclusters. Other contributions, induced by the presence of the support, can provide parallel channels for the reaction and modulate the final...

  9. Biosynthesis of gold nanoparticles using plant extracts.

    Science.gov (United States)

    Noruzi, Masumeh

    2015-01-01

    Because of the widespread use of metallic nanoparticles in biology, pharmaceuticals, and medicine, biosynthesis methods are being considered to prepare these nanoparticles. Among biosynthesis methods mentioned in the literature, the use of plant extracts has gained great importance due to the fact that most of the plants are generally inexpensive, available, and nontoxic. Moreover, plant extracts are rich in different types of reducing and capping agents. Therefore, these methods have a high potential for scale-up and can produce nanoparticles in different morphologies. In this paper, different green methods used to prepare metallic nanoparticles and the types of characterization methods for their identification have been comprehensively explained. Since gold nanoparticles are considered more biocompatible than other metallic nanoparticles, research studies performed on green synthesis of gold nanoparticles using plant extracts and different applications of these nanoparticles have been reviewed and discussed.

  10. Functionalization of gold nanoparticles as antidiabetic nanomaterial.

    Science.gov (United States)

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

    2013-12-01

    In the present investigation, functionalization of gold nanoparticles synthesized using propanoic acid 2-(3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl) (PAT) an active biocomponent isolated from Cassia auriculata is studied in detail. On reaction of PAT with aqueous HAuCl4, rapid formation of stable gold nanoparticles was achieved. Formation of gold nanoparticles was confirmed by UV-vis spectroscopy, XRD, GC-MS,FTIR, TEM and SEM with EDAX. Gold nanoparticles mostly were monodisperse, spherical in shape and ranged in size 12-41 nm. Gold nanoparticles synthesised using PAT was administered to alloxan (150 mg/kg body weight) induced diabetic male albino rats at different doses (0.25, 0.5, 0.75 and 1.0mg/kg body weight) for 28 days. Plasma glucose level, cholesterol and triglyceride were significantly (pgold nanoparticles at dosage of 0.5mg/kg body weight and plasma insulin increased significantly. The newly genre green gold nanoparticles exhibit remarkable protein tyrosine phosphatase 1B inhibitory activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Current methods for synthesis of gold nanoparticles.

    Science.gov (United States)

    Herizchi, Roya; Abbasi, Elham; Milani, Morteza; Akbarzadeh, Abolfazl

    2016-01-01

    Metal nanoparticles, such as nanoparticles synthesized using gold, have numerous uncommon chemical and physical properties due to the effects of their quantum size and their large surface area, in comparison with other metal atoms or bulk metal. Gold nanoparticles (GNPs), in particular, are very attractive because of their size and shape-dependent properties. Metal nanoparticles have gathered extensive attention due to their uncommon properties and promising applications in photonics, electronics, biochemical sensing, and imaging. This review covers recent advances in the synthesis of GNPs.

  12. Functionalized Gold Nanoparticles and Their Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Shree R. Singh

    2011-06-01

    Full Text Available Metal nanoparticles are being extensively used in various biomedical applications due to their small size to volume ratio and extensive thermal stability. Gold nanoparticles (GNPs are an obvious choice due to their amenability of synthesis and functionalization, less toxicity and ease of detection. The present review focuses on various methods of functionalization of GNPs and their applications in biomedical research. Functionalization facilitates targeted delivery of these nanoparticles to various cell types, bioimaging, gene delivery, drug delivery and other therapeutic and diagnostic applications. This review is an amalgamation of recent advances in the field of functionalization of gold nanoparticles and their potential applications in the field of medicine and biology.

  13. Gold Nanoparticle Labels Amplify Ellipsometric Signals

    Science.gov (United States)

    Venkatasubbarao, Srivatsa

    2008-01-01

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

  14. Functionalization of biosynthesized gold nanoparticle from aqueous ...

    African Journals Online (AJOL)

    The absorption peak of the biosynthesized Gold nanoparticle was found to be 545.5 nm and Zetasizer analysis showed that the average particle size was 28.5 nm with morphological structure of spherical and triangular shapes using SEM and TEM. EDAX confirmed the presence of element gold, carbon, oxygen and copper.

  15. Nonlinear optical studies of single gold nanoparticles

    NARCIS (Netherlands)

    Dijk, Meindert Alexander van

    2007-01-01

    Gold nanoparticles are spherical clusters of gold atoms, with diameters typically between 1 and 100 nanometers. The applications of these particles are rather diverse, from optical labels for biological experiments to data carrier for optical data storage. The goal of my project was to develop new

  16. Radiofrequency Heating Pathways for Gold Nanoparticles

    Science.gov (United States)

    Collins, C. B.; McCoy, R. S.; Ackerson, B. J.; Collins, G. J.

    2015-01-01

    This feature article reviews the thermal dissipation of nanoscopic gold under radiofrequency (RF) irradiation. It also presents previously unpublished data addressing obscure aspects of this phenomenon. While applications in biology motivated initial investigation of RF heating of gold nanoparticles, recent controversy concerning whether thermal effects can be attributed to nanoscopic gold highlight the need to understand the involved mechanism or mechanisms of heating. Both the nature of the particle and the nature of the RF field influence heating. Aspects of nanoparticle chemistry and physics, including the hydrodynamic diameter of the particle, the oxidation state and related magnetism of the core, and the chemical nature of the ligand shell may all strongly influence to what extent a nanoparticle heats in an RF field. Aspects of RF include: power, frequency and antenna designs that emphasize relative strength of magnetic or electric fields, and also influence the extent to which a gold nanoparticle heats in RF. These nanoparticle and RF properties are analysed in the context of three heating mechanisms proposed to explain gold nanoparticle heating in an RF field. This article also makes a critical analysis of the existing literature in the context of the nanoparticle preparations, RF structure, and suggested mechanisms in previously reported experiments. PMID:24962620

  17. Solid lipid nanoparticles for the controlled delivery of poorly water soluble non-steroidal anti-inflammatory drugs.

    Science.gov (United States)

    Kumar, Raj; Singh, Ashutosh; Garg, Neha; Siril, Prem Felix

    2018-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (IBP) are among the most prescribed drugs across the globe. However, most NSAIDs are insoluble in water leading them to have poor bioavailability and erratic absorption. Moreover, NSAIDs such as IBP and ketoprofen (KP) have to be administered very frequently due to their short plasma half-life leading to side effects. Controlled release formulations of IBP, KP and nabumetone (NBT) based on solid lipid nanoparticles (SLNs) were successfully synthesised in the present study to solve the above-mentioned challenges that are associated with NSAIDs. SLNs were prepared in two steps; hot-melt homogenization followed by sonication to formulate SLNs with spherical morphology. While capmul® GMS-50K (capmul) was used as the lipid due to the high solubility of the studied drugs in it, gelucire® 50/13 (gelucire) was used as the surfactant. It was found that particle size was directly proportional to drug concentration and inversely proportional to surfactant concentration, volume of water added and temperature of water. Ultrasonication in a pulse mode with optimum duration of 15min was essential to obtain smaller nanoparticles through the formation of a nanoemulsion. Drug loaded SLNs with small particle size and narrow size distribution with good solid loading, encapsulation efficiency and drug loading percentage could be prepared using the optimised conditions. SLNs prepared at the optimised condition were characterized thoroughly by using different techniques such as dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The cytotoxicity results showed that the prepared SLNs are non-toxic to Raw cell line. The drugs IBP, KP and NBT showed 53, 74 and 69% of percentage entrapment efficiency with

  18. Subchronic inhalation toxicity of gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Chung Yong

    2011-05-01

    Full Text Available Abstract Background Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the in vivo toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME of gold nanoparticles remain unclear. Results The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males and 145 g (females, were divided into 4 groups (10 rats in each group: fresh-air control, low-dose (2.36 × 104 particle/cm3, 0.04 μg/m3, middle-dose (2.36 × 105 particle/cm3, 0.38 μg/m3, and high-dose (1.85 × 106 particle/cm3, 20.02 μg/m3. The animals were exposed to gold nanoparticles (average diameter 4-5 nm for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH, and total protein were also monitored in a cellular bronchoalveolar lavage (BAL fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue

  19. Synthesis, characterization, DNA interaction and potential applications of gold nanoparticles functionalized with Acridine Orange fluorophores.

    Science.gov (United States)

    Biver, Tarita; Eltugral, Nurettin; Pucci, Andrea; Ruggeri, Giacomo; Schena, Alberto; Secco, Fernando; Venturini, Marcella

    2011-04-28

    Two new water-soluble gold nanoparticles (AO-TEG-Au and AO-PEG-Au NPs) are prepared and characterized. They are stabilized by thioalkylated oligoethylene glycols and functionalized with fluorescent Acridine Orange (AO) derivatives. Despite the different core sizes (11.8 and 3.9 nm respectively) and shell composition, they are both well dispersed and are stable in water, even if some self-aggregation is observed in the case of AO-TEG-Au NPs. However, AO-PEG-Au NPs show much lower emission efficiency with respect to AO-TEG-Au NPs. Spectrophotometric and spectrofluorometric experiments indicate that both types of nanoparticle are able to bind to calf thymus DNA, either by external binding or partial intercalation. Preliminary FACS flow cytometry tests seem to indicate that the AO-TEG-Au nanoparticle is able to cross the cell membrane where it is absorbed by Chinese hamster ovary (CHO) cells at the picomolar concentration level.

  20. Kanamycin Sulphate Loaded PLGA-Vitamin-E-TPGS Long Circulating Nanoparticles Using Combined Coating of PEG and Water-Soluble Chitosan

    Directory of Open Access Journals (Sweden)

    Sanaul Mustafa

    2017-01-01

    Full Text Available Kanamycin sulphate (KS is a Mycobacterium tuberculosis protein synthesis inhibitor. Due to its intense hydrophilicity, KS is cleared from the body within 8 h. KS has a very short plasma half-life (2.5 h. KS is used in high concentrations to reach the therapeutic levels in plasma, which results in serious nephrotoxicity/ototoxicity. To overcome aforementioned limitations, the current study aimed to develop KS loaded PLGA-Vitamin-E-TPGS nanoparticles (KS-PLGA-TPGS NPs, to act as an efficient carrier for controlled delivery of KS. To achieve a substantial extension in blood circulation, a combined design, affixation of polyethylene glycol (PEG to KS-PLGA-TPGS NPs and adsorption of water-soluble chitosan (WSC (cationic deacetylated chitin to particle surface, was raised for surface modification of NPs. Surface modified NPs (KS-PEG-WSC NPs were prepared to provide controlled delivery and circulate in the bloodstream for an extended period of time, thus minimizing dosing frequency. In vivo pharmacokinetics and in vivo biodistribution following intramuscular administration were investigated. NPs surface charge was close to neutral +3.61 mV and significantly affected by the WSC coating. KS-PEG-WSC NPs presented striking prolongation in blood circulation, reduced protein binding, and long drew-out the blood circulation half-life with resultant reduced kidney sequestration vis-à-vis KS-PLGA-TPGS NPs. The studies, therefore, indicate the successful formulation development of KS-PEG-WSC NPs with reduced frequency of dosing of KS indicating low incidence of nephrotoxicity/ototoxicity.

  1. Nucleation of gold nanoparticle superclusters from solution.

    Science.gov (United States)

    Yan, H; Cingarapu, S; Klabunde, K J; Chakrabarti, A; Sorensen, C M

    2009-03-06

    Measurements of the solubility curve of a quasi-monodisperse gold nanoparticle solution are given. Temperature quenches from the one-phase to the two-phase regime yielded superclusters of the nanoparticle solid phase with sizes that depended on the quench depth. Classical nucleation theory was used to describe these sizes using a value of the surface tension for the nanoparticle solid phase of 0.042 erg/cm2. This value is consistent with molecule size scaling of the surface tension. In total these results show that suspensions of nanoparticles act like molecular solutions.

  2. Gold nanoparticle assemblies through Hydrogen-bonded supramolecular mediators

    NARCIS (Netherlands)

    Kinge, S.S.; Crego Calama, Mercedes; Reinhoudt, David

    2007-01-01

    The synthesis of spherical gold nanoparticle assemblies with multicomponent double rosette molecular boxes as mediators is presented. These nine-component hydrogen-bonded supramolecular structures held together by 36 hydrogen bonds induce gold nanoparticle assembly. The morphologies of the

  3. Increased cellular uptake of peptide-modified PEGylated gold nanoparticles.

    Science.gov (United States)

    He, Bo; Yang, Dan; Qin, Mengmeng; Zhang, Yuan; He, Bing; Dai, Wenbing; Wang, Xueqing; Zhang, Qiang; Zhang, Hua; Yin, Changcheng

    2017-12-09

    Gold nanoparticles are promising drug delivery vehicles for nucleic acids, small molecules, and proteins, allowing various modifications on the particle surface. However, the instability and low bioavailability of gold nanoparticles compromise their clinical application. Here, we functionalized gold nanoparticles with CPP fragments (CALNNPFVYLI, CALRRRRRRRR) through sulfhydryl PEG to increase their stability and bioavailability. The resulting gold nanoparticles were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible spectrometry and X-ray photoelectron spectroscopy (XPS), and the stability in biological solutions was evaluated. Comparing to PEGylated gold nanoparticles, CPP (CALNNPFVYLI, CALRRRRRRRR)-modified gold nanoparticles showed 46 folds increase in cellular uptake in A549 and B16 cell lines, as evidenced by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). The interactions between gold nanoparticles and liposomes indicated CPP-modified gold nanoparticles bind to cell membrane more effectively than PEGylated gold nanoparticles. Surface plasmon resonance (SPR) was used to measure interactions between nanoparticles and the membrane. TEM and uptake inhibitor experiments indicated that the cellular entry of gold nanoparticles was mediated by clathrin and macropinocytosis. Other energy independent endocytosis pathways were also identified. Our work revealed a new strategy to modify gold nanoparticles with CPP and illustrated the cellular uptake pathway of CPP-modified gold nanoparticles. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Gold nanoparticles as absolute nano-thermometers.

    Science.gov (United States)

    Carattino, Aquiles; Caldarola, Martín; Orrit, Michel

    2017-12-22

    Nano-thermometry is a challenging field that can open the door to intriguing questions ranging from biology and medicine to material sciences. Gold nanorods are excellent candidates to act as nanoprobes because they are reasonably bright emitters upon excitation with a monochromatic source. Gold nanoparticles are commonly used in photothermal therapy as efficient transducers of electromagnetic radiation into heat. In this work we use the spectrum of the anti-Stokes emission from gold nanorods irradiated in resonance to measure the absolute temperature of the nanoparticles and their surrounding medium without the need for a previous calibration. We show a 4 K accuracy in the determination of the temperature of the medium with spectral measurements of 180 s integration time. This procedure can be easily implemented in any microscope capable of acquiring emission spectra and it is not limited to any specific shape of nanoparticles.

  5. Biosynthesis of gold nanoparticles: A green approach.

    Science.gov (United States)

    Ahmed, Shakeel; Annu; Ikram, Saiqa; Yudha S, Salprima

    2016-08-01

    Nanotechnology is an immensely developing field due to its extensive range of applications in different areas of technology and science. Different types of methods are employed for synthesis of nanoparticles due to their wide applications. The conventional chemical methods have certain limitations with them either in the form of chemical contaminations during their syntheses procedures or in later applications and use of higher energy. During the last decade research have been focussed on developing simple, clean, non-toxic, cost effective and eco-friendly protocols for synthesis of nanoparticles. In order to get this objective, biosynthesis methods have been developed in order to fill this gap. The biosynthesis of nanoparticles is simple, single step, eco-friendly and a green approach. The biochemical processes in biological agents reduce the dissolved metal ions into nano metals. The various biological agents like plant tissues, fungi, bacteria, etc. are used for biosynthesis for metal nanoparticles. In this review article, we summarised recent literature on biosynthesis of gold nanoparticles which have revolutionised technique of synthesis for their applications in different fields. Due to biocompatibility of gold nanoparticles, it has find its applications in biomedical applications. The protocol and mechanism of biosynthesis of gold nanoparticles along with various applications have also been discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Inhibition of HIV fusion with multivalent gold nanoparticles.

    Science.gov (United States)

    Bowman, Mary-Catherine; Ballard, T Eric; Ackerson, Christopher J; Feldheim, Daniel L; Margolis, David M; Melander, Christian

    2008-06-04

    The design and synthesis of a multivalent gold nanoparticle therapeutic is presented. SDC-1721, a fragment of the potent HIV inhibitor TAK-779, was synthesized and conjugated to 2.0 nm diameter gold nanoparticles. Free SDC-1721 had no inhibitory effect on HIV infection; however, the (SDC-1721)-gold nanoparticle conjugates displayed activity comparable to that of TAK-779. This result suggests that multivalent presentation of small molecules on gold nanoparticle surfaces can convert inactive drugs into potent therapeutics.

  7. Inhibition of HIV Fusion with Multivalent Gold Nanoparticles

    OpenAIRE

    Bowman, Mary-Catherine; Ballard, T. Eric; Ackerson, Christopher J.; Feldheim, Daniel L.; Margolis, David M.; Melander, Christian

    2008-01-01

    The design and synthesis of a multivalent gold nanoparticle therapeutic is presented. SDC-1721, a fragment of the potent HIV inhibitor TAK-779, was synthesized and conjugated to 2.0 nm diameter gold nanoparticles. Free SDC-1721 had no inhibitory effect on HIV infection; however, the (SDC-1721)-gold nanoparticle conjugates displayed activity comparable to that of TAK-779. This result suggests that multivalent presentation of small molecules on gold nanoparticle surfaces can convert inactive dr...

  8. Formation of gold nanoparticles by glycolipids of Lactobacillus casei

    OpenAIRE

    Fumiya Kikuchi; Yugo Kato; Kazuo Furihata; Toshihiro Kogure; Yuki Imura; Etsuro Yoshimura; Michio Suzuki

    2016-01-01

    Gold nanoparticles have particular properties distinct from those of bulk gold crystals, and such nanoparticles are used in various applications in optics, catalysis, and drug delivery. Many reports on microbial synthesis of gold nanoparticles have appeared. However, the molecular details (reduction and dispersion) of such synthesis remain unclear. In the present study, we studied gold nanoparticle synthesis by Lactobacillus casei. A comparison of L. casei components before and after addition...

  9. Gold-coated nanoparticles for use in biotechnology applications

    Science.gov (United States)

    Berning, Douglas E [Los Alamos, NM; Kraus, Jr., Robert H.; Atcher, Robert W [Los Alamos, NM; Schmidt, Jurgen G [Los Alamos, NM

    2009-07-07

    A process of preparing gold-coated magnetic nanoparticles is disclosed and includes forming a suspension of magnetic nanoparticles within a suitable liquid, adding an amount of a reducible gold compound and a reducing agent to the suspension, and, maintaining the suspension for time sufficient to form gold-coated magnetic nanoparticles.

  10. Radiofrequency heating pathways for gold nanoparticles.

    Science.gov (United States)

    Collins, C B; McCoy, R S; Ackerson, B J; Collins, G J; Ackerson, C J

    2014-08-07

    This feature article reviews the thermal dissipation of nanoscopic gold under radiofrequency (RF) irradiation. It also presents previously unpublished data addressing obscure aspects of this phenomenon. While applications in biology motivated initial investigation of RF heating of gold nanoparticles, recent controversy concerning whether thermal effects can be attributed to nanoscopic gold highlight the need to understand the involved mechanism or mechanisms of heating. Both the nature of the particle and the nature of the RF field influence heating. Aspects of nanoparticle chemistry which may affect thermal dissipation include the hydrodynamic diameter of the particle, the oxidation state and related magnetism of the core, and the chemical nature of the ligand shell. Aspects of RF which may affect thermal dissipation include power, frequency and antenna designs that emphasize relative strength of magnetic or electric fields. These nanoparticle and RF properties are analysed in the context of three heating mechanisms proposed to explain gold nanoparticle heating in an RF field. This article also makes a critical analysis of the existing literature in the context of the nanoparticle preparations, RF structure, and suggested mechanisms in previously reported experiments.

  11. Phosphomolybdate-doped-poly(3,4-ethylenedioxythiophene) coated gold nanoparticles: Synthesis, characterization and electrocatalytic reduction of bromate

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Syeda Sara [School of Chemistry, Monash University, VIC 3800 (Australia); National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Liu, Yuping [School of Chemistry, Monash University, VIC 3800 (Australia); Sirajuddin,; Solangi, Amber Rehana [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Bond, Alan M., E-mail: alan.bond@monash.edu [School of Chemistry, Monash University, VIC 3800 (Australia); Zhang, Jie, E-mail: jie.zhang@monash.edu [School of Chemistry, Monash University, VIC 3800 (Australia)

    2013-11-25

    Graphical abstract: -- Highlights: •Stable and water soluble phosphomolybdate-doped-PEDOT coated gold nanoparticles were synthesized. •Electrodes modified with these nanoparticles show well defined voltammetric response and excellent stability in acidic media. •These nanocomposite catalysts exhibit an excellent catalytic activity towards electroreduction of bromate. -- Abstract: Phosphomolybdate, H{sub 3}PMo{sub 12}O{sub 40}, (PMo{sub 12})-doped-poly(3,4-ethylenedioxythiophene) (PEDOT) coated gold nanoparticles have been synthesized in aqueous solution by reduction of AuCl{sub 4}{sup −} using hydroxymethyl EDOT as a reducing agent in the presence of polystyrene sulfonate and PMo{sub 12}. The resulting PMo{sub 12}-doped-PEDOT stabilized Au nanoparticles are water soluble and have been characterized by UV–visible spectroscopy, scanning electron microscopy and electrochemistry. Glassy carbon electrodes modified with these Au nanoparticles show excellent stability and catalytic activity towards the reduction of bromate in an aqueous electrolyte solution containing 10 mM H{sub 2}SO{sub 4} and 0.1 M Na{sub 2}SO{sub 4}.

  12. Applications of gold nanoparticles in cancer nanotechnology

    Directory of Open Access Journals (Sweden)

    Weibo Cai

    2008-09-01

    Full Text Available Weibo Cai1,2, Ting Gao3, Hao Hong1, Jiangtao Sun11Departments of Radiology and Medical Physics, School of Medicine and Public Health, University of Wisconsin – Madison, Madison, Wisconsin, USA; 2University of Wisconsin Paul P. Carbone Comprehensive Cancer Center, Madison, Wisconsin, USA; 3Tyco Electronics Corporation, 306 Constitution Drive, Menlo Park, California, USAAbstract: It has been almost 4 decades since the “war on cancer” was declared. It is now generally believed that personalized medicine is the future for cancer patient management. Possessing unprecedented potential for early detection, accurate diagnosis, and personalized treatment of cancer, nanoparticles have been extensively studied over the last decade. In this review, we will summarize the current state-of-the-art of gold nanoparticles in biomedical applications targeting cancer. Gold nanospheres, nanorods, nanoshells, nanocages, and surface enhanced Raman scattering nanoparticles will be discussed in detail regarding their uses in in vitro assays, ex vivo and in vivo imaging, cancer therapy, and drug delivery. Multifunctionality is the key feature of nanoparticle-based agents. Targeting ligands, imaging labels, therapeutic drugs, and other functionalities can all be integrated to allow for targeted molecular imaging and molecular therapy of cancer. Big strides have been made and many proof-of-principle studies have been successfully performed. The future looks brighter than ever yet many hurdles remain to be conquered. A multifunctional platform based on gold nanoparticles, with multiple receptor targeting, multimodality imaging, and multiple therapeutic entities, holds the promise for a “magic gold bullet” against cancer.Keywords: gold nanoparticles, cancer, nanotechnology, optical imaging, nanomedicine, molecular therapy

  13. Surface interactions between gold nanoparticles and biochar

    Science.gov (United States)

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

  14. Synthesis and characterization of gold nanoparticles incorporated ...

    Indian Academy of Sciences (India)

    Synthesis and characterization of gold nanoparticles incorporated bentonite clay for electrocatalytic sensing of arsenic(III). Pankaj Kumar Rastogi Dharmendra Kumar Yadav Shruti Pandey Vellaichamy Ganesan Piyush Kumar Sonkar Rupali Gupta. Regular Articles Volume 128 Issue 3 March 2016 pp 349-356 ...

  15. Reversible multi polyelectrolyte layers on gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Djoumessi Lekeufack, Diane; Brioude, Arnaud, E-mail: arnaud.brioude@univ-lyon1.fr [UMR CNRS 5615, Universite Claude Bernard Lyon 1, Laboratoire des Multimateriaux et Interfaces (LMI) (France); Lalatonne, Yoann; Motte, Laurence [UMR 7244 CNRS, Universite Paris 13, Laboratoire CSPBAT (France); Coleman, Anthony W.; Miele, Philippe [UMR CNRS 5615, Universite Claude Bernard Lyon 1, Laboratoire des Multimateriaux et Interfaces (LMI) (France)

    2012-06-15

    Gold nanoparticles surface can be easily modified by different molecules such as polyelectrolytes. In a typical multilayer system made of polyethyleneimine and poly(styrene sulfonate)sodium alternated layers around gold nanoparticles, we have evaluated the interactions between the different layers and the relative strength of interfacial properties. By means of UV-Visible and FTIR spectroscopies, we have shown that due to its amine functionalities, the bonding of polyethyleneimine to gold particles is stronger than the one implied with the sulfonate anion in the PSS inducing a clean removal of this latter after the last polyethyleneimine deposition. Considering that polyethyleneimine is cytotoxic and that only weak covalent bonds are concerned in polyelectrolyte multilayer, this last point is of main importance since external degradation thus exposing polyethyleneimine sub-layer of multilayer films to in vivo tissue cells can occur by many ways.

  16. Rapid biosynthesis of irregular shaped gold nanoparticles from macerated aqueous extracellular dried clove buds (Syzygium aromaticum) solution.

    Science.gov (United States)

    Raghunandan, Deshpande; Bedre, Mahesh D; Basavaraja, S; Sawle, Balaji; Manjunath, S Y; Venkataraman, A

    2010-08-01

    In this paper, we stress upon rapid synthesis of irregular shape gold nanoparticles from a biological base. Treatment of macerated extracellular aqueous dried clove buds (Syzygium aromaticum) solution with the aqueous gold salt solution yielded irregular shaped stable gold nanoparticles in the range of 5-100 nm. The synthesis and morphology of these gold nanoparticles are understood by UV (UV-vis spectroscopy), FESEM (field emission scanning electron microscopy), TEM (transmission electron microscopy) and AFM (atomic force microscopy) techniques. The formation of these bio-adsorbed gold nanoparticles is rapid as the reaction process completes within few minutes. The XRD (X-ray diffraction studies) and EDAX (energy dispersive X-ray analysis) show that the particles are crystalline in nature. This clean-green method of synthesis is performed under ambient conditions. Probable biochemical pathway of the synthesis is studied using FTIR (Fourier transformed infrared spectroscopy). It is observed that the freely water soluble flavonoids of clove buds are responsible for bioreduction. The possible applications viz., catalysis, sensor, diagnostics, biomedical imaging and photo thermal therapy of these functionalized noble metal nanoparticles are envisaged. Copyright 2010 Elsevier B.V. All rights reserved.

  17. Antifungal activity of gold nanoparticles prepared by solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Manzoor, Nikhat; Ahmad, Aijaz [Department of Biosciences, Jamia Millia Islamia, New Delhi 110025 (India); Ahmed, Jahangeer [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Al-Shihri, Ayed S. [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia)

    2013-01-15

    Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m{sup 2}/g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m{sup 2/}g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl{sub 2} and NaBH{sub 4} as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl{sub 2}, however, NaBH{sub 4} produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m{sup 2}/g for 7 nm and 269 m{sup 2}/g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H{sup +} efflux of the Candida species than 15 nm sized gold nanoparticles.

  18. A halogen-free synthesis of gold nanoparticles using gold(III) oxide

    OpenAIRE

    Sashuk, Volodymyr; Rogaczewski, Konrad

    2016-01-01

    Gold nanoparticles are one of the most used nanomaterials. They are usually synthesized by the reduction of gold(III) chloride. However, the presence of halide ions in the reaction mixture is not always welcome. In some cases, these ions have detrimental influence on the morphology and structure of resulting nanoparticles. Here, we present a simple and halogen-free procedure to prepare gold nanoparticles by reduction of gold(III) oxide in neat oleylamine. The method provides the particles wit...

  19. A green chemistry approach for synthesizing biocompatible gold nanoparticles.

    Science.gov (United States)

    Gurunathan, Sangiliyandi; Han, JaeWoong; Park, Jung Hyun; Kim, Jin-Hoi

    2014-01-01

    Gold nanoparticles (AuNPs) are a fascinating class of nanomaterial that can be used for a wide range of biomedical applications, including bio-imaging, lateral flow assays, environmental detection and purification, data storage, drug delivery, biomarkers, catalysis, chemical sensors, and DNA detection. Biological synthesis of nanoparticles appears to be simple, cost-effective, non-toxic, and easy to use for controlling size, shape, and stability, which is unlike the chemically synthesized nanoparticles. The aim of this study was to synthesize homogeneous AuNPs using pharmaceutically important Ganoderma spp. We developed a simple, non-toxic, and green method for water-soluble AuNP synthesis by treating gold (III) chloride trihydrate (HAuCl4) with a hot aqueous extract of the Ganoderma spp. mycelia. The formation of biologically synthesized AuNPs (bio-AuNPs) was characterized by ultraviolet (UV)-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the biocompatibility of as-prepared AuNPs was evaluated using a series of assays, such as cell viability, lactate dehydrogenase leakage, and reactive oxygen species generation (ROS) in human breast cancer cells (MDA-MB-231). The color change of the solution from yellow to reddish pink and strong surface plasmon resonance were observed at 520 nm using UV-visible spectroscopy, and that indicated the formation of AuNPs. DLS analysis revealed the size distribution of AuNPs in liquid solution, and the average size of AuNPs was 20 nm. The size and morphology of AuNPs were investigated using TEM. The biocompatibility effect of as-prepared AuNPs was investigated in MDA-MB-231 breast cancer cells by using various concentrations of AuNPs (10 to 100 μM) for 24 h. Our findings suggest that AuNPs are non-cytotoxic and biocompatible. To the best of our knowledge

  20. A green chemistry approach for synthesizing biocompatible gold nanoparticles

    Science.gov (United States)

    Gurunathan, Sangiliyandi; Han, JaeWoong; Park, Jung Hyun; Kim, Jin-Hoi

    2014-05-01

    Gold nanoparticles (AuNPs) are a fascinating class of nanomaterial that can be used for a wide range of biomedical applications, including bio-imaging, lateral flow assays, environmental detection and purification, data storage, drug delivery, biomarkers, catalysis, chemical sensors, and DNA detection. Biological synthesis of nanoparticles appears to be simple, cost-effective, non-toxic, and easy to use for controlling size, shape, and stability, which is unlike the chemically synthesized nanoparticles. The aim of this study was to synthesize homogeneous AuNPs using pharmaceutically important Ganoderma spp . We developed a simple, non-toxic, and green method for water-soluble AuNP synthesis by treating gold (III) chloride trihydrate (HAuCl4) with a hot aqueous extract of the Ganoderma spp . mycelia. The formation of biologically synthesized AuNPs (bio-AuNPs) was characterized by ultraviolet (UV)-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the biocompatibility of as-prepared AuNPs was evaluated using a series of assays, such as cell viability, lactate dehydrogenase leakage, and reactive oxygen species generation (ROS) in human breast cancer cells (MDA-MB-231). The color change of the solution from yellow to reddish pink and strong surface plasmon resonance were observed at 520 nm using UV-visible spectroscopy, and that indicated the formation of AuNPs. DLS analysis revealed the size distribution of AuNPs in liquid solution, and the average size of AuNPs was 20 nm. The size and morphology of AuNPs were investigated using TEM. The biocompatibility effect of as-prepared AuNPs was investigated in MDA-MB-231 breast cancer cells by using various concentrations of AuNPs (10 to 100 μM) for 24 h. Our findings suggest that AuNPs are non-cytotoxic and biocompatible. To the best of our knowledge

  1. X-ray optics of gold nanoparticles.

    Science.gov (United States)

    Letfullin, Renat R; Rice, Colin E W; George, Thomas F

    2014-11-01

    Gold nanoparticles have been investigated as contrast agents for traditional x-ray medical procedures, utilizing the strong absorption characteristics of the nanoparticles to enhance the contrast of the detected x-ray image. Here we use the Kramers-Kronig relation for complex atomic scattering factors to find the real and imaginary parts of the index of refraction for the medium composed of single-element materials or compounds in the x-ray range of the spectrum. These complex index of refraction values are then plugged into a Lorenz-Mie theory to calculate the absorption efficiency of various size gold nanoparticles for photon energies in the 1-100 keV range. Since the output from most medical diagnostic x-ray devices follows a wide and filtered spectrum of photon energies, we introduce and compute the effective intensity-absorption-efficiency values for gold nanoparticles of radii varying from 5 to 50 nm, where we use the TASMIP model to integrate over all spectral energies generated by typical tungsten anode x-ray tubes with kilovolt potentials ranging from 50 to 150 kVp.

  2. Water-soluble vitamins.

    Science.gov (United States)

    Konings, Erik J M

    2006-01-01

    Simultaneous Determination of Vitamins.--Klejdus et al. described a simultaneous determination of 10 water- and 10 fat-soluble vitamins in pharmaceutical preparations by liquid chromatography-diode-array detection (LC-DAD). A combined isocratic and linear gradient allowed separation of vitamins in 3 distinct groups: polar, low-polar, and nonpolar. The method was applied to pharmaceutical preparations, fortified powdered drinks, and food samples, for which results were in good agreement with values claimed. Heudi et al. described a separation of 9 water-soluble vitamins by LC-UV. The method was applied for the quantification of vitamins in polyvitaminated premixes used for the fortification of infant nutrition products. The repeatability of the method was evaluated at different concentration levels and coefficients of variation were principle in a specific and sensitive method for the determination of free and bound pantothenic acid in a large variety of foods. A French laboratory invited European laboratories to participate in a series of collaborative studies for this method, which will be carried out in 2005/2006. A more sophisticated method was described by Mittermayer et al. They developed an LC-mass spectrometry (LC/MS) method for the determination of vitamin B5 in a wide range of fortified food products. Application of the method to various samples showed consistent results with those obtained by microbiology. Vitamin B6.-Method 2004.07, an LC method for the analysis of vitamin B6 in reconstituted infant formula, was published by Mann et al. In contrast with this method, which quantifies vitamin B6 after converting the phosphorylated and free vitamers into pyridoxine, Viñas et al. published an LC method which determines 6 vitamin B6 related compounds, the 3 B6 vitamers, their corresponding phosphorylated esters, and a metabolite. Accuracy was determined using 2 CRMs. Results were within the certified ranges. Vitamin C.-Franke et al. described an extensive

  3. Synthesis of gold nanoparticles using various amino acids.

    Science.gov (United States)

    Maruyama, Tatsuo; Fujimoto, Yuhei; Maekawa, Tetsuya

    2015-06-01

    Gold nanoparticles (4-7nm) were synthesized from tetraauric acid using various amino acids as reducing and capping agents. The gold nanoparticles were produced from the incubation of a AuCl4(-) solution with an amino acid at 80°C for 20min. Among the twenty amino acids tested, several amino acids produced gold nanoparticles. The color of the nanoparticle solutions varied with the amino acids used for the reduction. We adopted l-histidine as a reducing agent and investigated the effects of the synthesis conditions on the gold nanoparticles. The His and AuCl4(-) concentrations affected the size of the gold nanoparticles and their aggregates. The pH of the reaction solution also affected the reaction yields and the shape of the gold nanoparticles. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Gold nanoparticles: preparation, functionalisation and applications in biochemistry and immunochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Dykman, Lev A; Bogatyrev, Vladimir A [Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences (Russian Federation)

    2007-02-28

    The review summarises data on the synthesis and functionalisation of gold nanoparticles and their applications in biological investigations. Particular attention is given to applications of colloidal gold in solid-phase assays, immunoassay and studies of biologically active compounds by vibrational spectroscopy. A special section deals with the use of gold nanoparticles as antigen carriers in immunisation.

  5. Controlled synthesis and optical properties of pure gold nanoparticles

    NARCIS (Netherlands)

    Singh, A.K.; Rai, A.K.; Bicanic, D.D.

    2009-01-01

    Gold nanoparticles were synthesized by laser ablation of a gold metallic disc at wavelengths of 532 nm and 355 nm with 7 ns pulse duration in the pure water. The colloidal gold nanoparticles were characterized by ultraviolet-visible absorption spectroscopy, transmission electron microscopy, and

  6. Protracted elimination of gold nanoparticles from mouse liver

    DEFF Research Database (Denmark)

    Sadauskas, Evaldas; Wallin, Håkan; Stoltenberg, Meredin

    2009-01-01

    The present study aims at revealing the fate of 40-nm gold nanoparticles after intravenous injections. The gold nanoparticles were traced histochemically with light and transmission electron microscopy using autometallographic (AMG) staining, and the gold content in the liver was determined...

  7. Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles.

    Science.gov (United States)

    Poonthiyil, Vivek; Lindhorst, Thisbe K; Golovko, Vladimir B; Fairbanks, Antony J

    2018-01-01

    Glycoscience, despite its myriad of challenges, promises to unravel the causes of, potential new detection methods for, and novel therapeutic strategies against, many disease states. In the last two decades, glyco-gold nanoparticles have emerged as one of several potential new tools for glycoscientists. Glyco-gold nanoparticles consist of the unique structural combination of a gold nanoparticle core and an outer-shell comprising multivalent presentation of carbohydrates. The combination of the distinctive physicochemical properties of the gold core and the biological function/activity of the carbohydrates makes glyco-gold nanoparticles a valuable tool in glycoscience. In this review we present recent advances made in the use of one type of click chemistry, namely the azide-alkyne Huisgen cycloaddition, for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles.

  8. Gold Nanoparticles: Synthesis and Applications in Drug Delivery ...

    African Journals Online (AJOL)

    This review is focused essentially on the synthesis and applications of gold nanoparticles in the field of medicine and targeted drug delivery. Nanotechnology has become one of the most interesting and advanced areas of research in this field. Among nanoparticles, gold nanoparticles demonstrate special advantages in ...

  9. Gold Nanoparticles for Modulating Neuronal Behavior

    Directory of Open Access Journals (Sweden)

    Chiara Paviolo

    2017-04-01

    Full Text Available Understanding the detailed functioning and pathophysiology of the brain and the nervous system continues to challenge the scientific community, particularly in terms of scaling up techniques for monitoring and interfacing with complex 3D networks. Nanotechnology has the potential to support this scaling up, where the eventual goal would be to address individual nerve cells within functional units of both the central and peripheral nervous system. Gold nanoparticles provide a variety of physical and chemical properties that have attracted attention as a light-activated nanoscale neuronal interface. This review provides a critical overview of the photothermal and photomechanical properties of chemically functionalized gold nanoparticles that have been exploited to trigger a range of biological responses in neuronal tissues, including modulation of electrical activity and nerve regeneration. The prospects and challenges for further development are also discussed.

  10. Functional gold nanoparticles for optical affinity biosensing

    Czech Academy of Sciences Publication Activity Database

    Špringer, Tomáš; Chadtová Song, Xue; Ermini, Maria Laura; Lamačová, Josefína; Homola, Jiří

    2017-01-01

    Roč. 409, č. 16 (2017), s. 4087-4097 ISSN 1618-2642 R&D Projects: GA ČR(CZ) GBP205/12/G118 Grant - others:AV ČR(CZ) AP1101 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985882 Keywords : Gold nanoparticles * Cancer marker carcinoembryonic antigen * Surface plasmon resonance Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.431, year: 2016

  11. Detection of squamous carcinoma cells using gold nanoparticles

    Science.gov (United States)

    Dai, Wei-Yun; Lee, Sze-tsen; Hsu, Yih-Chih

    2015-03-01

    The goal of this study is to use gold nanoparticle as a diagnostic agent to detect human squamous carcinoma cells. Gold nanoparticles were synthesized and the gold nanoparticle size was 34.3 ± 6.2 nm. Based on the over-expression of epidermal growth factor receptor (EGFR) biomarkers in squamous carcinoma cells, we hypothesized that EGFR could be a feasible biomarker with a target moiety for detection. We further modified polyclonal antibodies of EGFR on the surface of gold nanoparticles. We found selected squamous carcinoma cells can be selectively detected using EGFR antibody-modified gold nanoparticles via receptor-mediated endocytosis. Cell death was also examined to determine the survival status of squamous carcinoma cells with respect to gold nanoparticle treatment and EGFR polyclonal antibody modification.

  12. Microbial synthesis of gold nanoparticles: current status and future prospects.

    Science.gov (United States)

    Shedbalkar, Utkarsha; Singh, Richa; Wadhwani, Sweety; Gaidhani, Sharvari; Chopade, B A

    2014-07-01

    Gold nanoparticles have been employed in biomedicine since the last decade because of their unique optical, electrical and photothermal properties. Present review discusses the microbial synthesis, properties and biomedical applications of gold nanoparticles. Different microbial synthesis strategies used so far for obtaining better yield and stability have been described. It also includes different methods used for the characterization and analysis of gold nanoparticles, viz. UV-visible spectroscopy, Fourier transform infrared spectroscopy, X ray diffraction spectroscopy, scanning electron microscopy, ransmission electron microscopy, atomic force microscopy, electron dispersive X ray, X ray photoelectron spectroscopy and cyclic voltametry. The different mechanisms involved in microbial synthesis of gold nanoparticles have been discussed. The information related to applications of microbially synthesized gold nanoparticles and patents on microbial synthesis of gold nanoparticles has been summarized. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Photochemical Synthesis of the Bioconjugate Folic Acid-Gold Nanoparticles

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Bertel, Linda; Páez-Mozo, Edgar

    2013-01-01

    In this paper we present a rapid and simple onepot method to obtain gold nanoparticles functionalized with folic acid using a photochemistry method. The bioconjugate folic acid-gold nanoparticle was generated in one step using a photo-reduction method, mixing hydrogen tetrachloroaurate with folic...... at 4°C prolongs the stability of folic acid-gold nanoparticle suspensions to up to 26 days. Ultraviolet visible and Fourier transform infrared spectroscopy showed a surface plasmon band of around 534nm and fluorescence spectroscopy exhibited a quenching effect on gold nanoparticles in the fluorescence...... emission of folic acid and thus confirmed the conjugation of folic acid to the surface of gold nanoparticles. In this study we demonstrate the use of a photochemistry method to obtain folic acid-gold nanoparticles in a simple and rapid way without the use of surfactants and long reaction times...

  14. Formation and Aggregation of Gold (Electrum Nanoparticles in Epithermal Ores

    Directory of Open Access Journals (Sweden)

    James A. Saunders

    2017-09-01

    Full Text Available Here, we review the concept that nanoparticles and colloids may have played a significant role in forming some types of hydrothermal ores deposits, particularly epithermal. This concept was first proposed almost a century ago but the development of new analytical technologies, lab experiments, and the discovery of new epithermal deposits where nanoparticles are evident have added credence to the “gold colloid theory”. Nanoparticles are defined to have at least one dimension <10−7 m, and may have different chemical and physical properties than the bulk solids. Colloids are typically <10−6 m in diameter and have the added characteristic that they are dispersed in another medium. In epithermal ore-forming solutions, gold or electrum nanoparticles nucleate from supersaturated hydrothermal solutions, and thus this is a “far-from-equilibrium” process. In some cases, gold nanoparticles may simply play a transitory role of aggregating to form much coarser-grained crystals, where all of the evidence of nanoparticles precursor phases is not preserved. However, in some epithermal ores, silica nanoparticles also formed, and their co-deposition with gold (electrum nanoparticles preserved the gold aggregation features as self-organized “fractal” dendrites. Here, we review existing the data on gold and electrum nanoparticles in epithermal ores, present images of electrum nanoparticles and their aggregates, and discuss the significance of gold nanoparticles formation and aggregation in helping to produce some of the highest-grade gold ores in the world.

  15. Asymmetric dumbbell-shaped silver nanoparticles and spherical gold nanoparticles green-synthesized by mangosteen (Garcinia mangostana) pericarp waste extracts.

    Science.gov (United States)

    Park, Ji Su; Ahn, Eun-Young; Park, Youmie

    2017-01-01

    Mangosteen ( Garcinia mangostana ) pericarp waste extract was used to synthesize gold and silver nanoparticles by a green strategy. The extract was both a reducing and stabilizing agent during synthesis. Phytochemical screening of the extract was conducted to obtain information regarding the presence/absence of primary and secondary metabolites in the extract. The in vitro antioxidant activity results demonstrated that the extract had excellent antioxidant activity, which was comparable to a standard (butylated hydroxy toluene). Spherical gold nanoparticles (gold nanoparticles green synthesized by mangosteen pericarp extract [GM-AuNPs]) with an average size of 15.37±3.99 to 44.20±16.99 nm were observed in high-resolution transmission electron microscopy (HR-TEM) images. Most interestingly, the silver nanoparticles (silver nanoparticles green synthesized by mangosteen pericarp extract [GM-AgNPs]) had asymmetric nanodumbbell shapes where one tail grew from a spherical head. The average head size was measured to be 13.65±5.07 to 31.08±3.99 nm from HR-TEM images. The hydrodynamic size of both nanoparticles tended to increase with increasing extract concentration. Large negative zeta potentials (-18.92 to -34.77 mV) suggested that each nanoparticle solution possessed excellent colloidal stability. The reaction yields were 99.7% for GM-AuNPs and 82.8% for GM-AgNPs, which were assessed by inductively coupled plasma optical emission spectroscopy. A high-resolution X-ray diffraction pattern confirmed the face-centered cubic structure of both nanoparticles. Based on phytochemical screening and Fourier transform infrared spectra, the hydroxyl functional groups of carbohydrates, flavonoids, glycosides, and phenolic compounds were most likely involved in a reduction reaction of gold or silver salts to their corresponding nanoparticles. The in vitro cytotoxicity (based on a water-soluble tetrazolium assay) demonstrated that GM-AgNPs were toxic to both A549 (a human lung

  16. Methanobactin-Mediated One-Step Synthesis of Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2013-11-01

    Full Text Available Preparation of gold nanoparticles with a narrow size distribution has enormous importance in nanotechnology. Methanobactin (Mb is a copper-binding small peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and catalytically reduce Au (III to Au (0. In this study, we demonstrate a facile Mb-mediated one-step synthetic route to prepare monodispersed gold nanoparticles. Continuous reduction of Au (III by Mb can be achieved by using hydroquinone as the reducing agent. The gold nanoparticles have been characterized by UV-visible spectroscopy. The formation and the surface plasmon resonance properties of the gold nanoparticles are highly dependent on the ratio of Au (III to Mb in solution. X-ray photoelectron spectroscopy (XPS, fluorescence spectra and Fourier transform-infrared spectroscopy (FT-IR spectra suggest that Mb molecules catalytically reduce Au (III to Au (0 with the concomitant production of gold nanoparticles, and then, Mb statically adsorbed onto the surface of gold nanoparticles to form an Mb-gold nanoparticles assembly. This avoids secondary nucleation. The formed gold nanoparticles have been demonstrated to be monodispersed and uniform by transmission electron microscopy (TEM images. Analysis of these particles shows an average size of 14.9 nm with a standard deviation of 1.1 nm. The gold nanoparticles are extremely stable and can resist aggregation, even after several months.

  17. Methanobactin-Mediated One-Step Synthesis of Gold Nanoparticles

    Science.gov (United States)

    Xin, Jia-ying; Cheng, Dan-dan; Zhang, Lan-xuan; Lin, Kai; Fan, Hong-chen; Wang, Yan; Xia, Chun-gu

    2013-01-01

    Preparation of gold nanoparticles with a narrow size distribution has enormous importance in nanotechnology. Methanobactin (Mb) is a copper-binding small peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and catalytically reduce Au (III) to Au (0). In this study, we demonstrate a facile Mb-mediated one-step synthetic route to prepare monodispersed gold nanoparticles. Continuous reduction of Au (III) by Mb can be achieved by using hydroquinone as the reducing agent. The gold nanoparticles have been characterized by UV-visible spectroscopy. The formation and the surface plasmon resonance properties of the gold nanoparticles are highly dependent on the ratio of Au (III) to Mb in solution. X-ray photoelectron spectroscopy (XPS), fluorescence spectra and Fourier transform-infrared spectroscopy (FT-IR) spectra suggest that Mb molecules catalytically reduce Au (III) to Au (0) with the concomitant production of gold nanoparticles, and then, Mb statically adsorbed onto the surface of gold nanoparticles to form an Mb-gold nanoparticles assembly. This avoids secondary nucleation. The formed gold nanoparticles have been demonstrated to be monodispersed and uniform by transmission electron microscopy (TEM) images. Analysis of these particles shows an average size of 14.9 nm with a standard deviation of 1.1 nm. The gold nanoparticles are extremely stable and can resist aggregation, even after several months. PMID:24189217

  18. Biosynthesis of gold nanoparticles, scope and application: a review

    National Research Council Canada - National Science Library

    Tikariha, S; Singh, S; Banerjee, S; Vidyarthi, A.S

    2012-01-01

    The synthesis of gold nanoparticles has received considerable attention and has been a focus of research due to their high chemical and thermal stability, fascinating optical, electronic properties...

  19. Microbial biosynthesis of nontoxic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Swarup, E-mail: swaruproy@klyuniv.ac.in [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Das, Tapan Kumar [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Maiti, Guru Prasad [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India); Department of Anesthesiology, Texas Tech University Health science Center, 3601 4th Street, Lubbock, TX 79430 (United States); Basu, Utpal [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India)

    2016-01-15

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  20. Facially amphiphilic thiol capped gold and silver nanoparticles

    Indian Academy of Sciences (India)

    Abstract. A series of bile acid-derived facially amphiphilic thiols have been used to cap sliver and gold nanoparticles. The self-assembling properties of these steroid-capped nanoparticles have been investigated and reported in this article.

  1. Amoxicillin functionalized gold nanoparticles reverts MRSA resistance

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, Sanjeeb; Kandimalla, Raghuram; Sharma, Kaustav Kalyan [Drug Discovery Lab, Life Science Division, Institute of Advanced Study in Science and Technology (IASST), Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Kataki, Amal Chandra [Dr. B. Borooah Cancer Institute, Guwahati, Assam (India); Department of Applied Sciences, Gopinath Bordoloi Nagar, Jalukbari, Gauhati University, Guwahati 781014, Assam (India); Deka, Manab [Department of Applied Sciences, Gopinath Bordoloi Nagar, Jalukbari, Gauhati University, Guwahati 781014, Assam (India); Kotoky, Jibon, E-mail: jkotoky@gmail.com [Drug Discovery Lab, Life Science Division, Institute of Advanced Study in Science and Technology (IASST), Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India)

    2016-04-01

    In this study, we have described the biosynthesis of biocompatible gold nanoparticles (GNPs) from aqueous extract of the aerial parts of a pteridophyte, “Adiantum philippense” by microwave irradiation and its surface functionalization with broad spectrum beta lactam antibiotic, amoxicillin (Amox). The functionalization of amoxicillin on GNPs (GNP-Amox) was carried out via electrostatic interaction of protonated amino group and thioether moiety mediated attractive forces. The synthesized GNPs and GNP-Amox were physicochemically characterized. UV–Vis spectroscopy, Zeta potential, XRD, FTIR and SERS (surface enhanced raman spectra) results confirmed the loading of Amox into GNPs. Loading of Amox to GNPs reduce amoxicillin cytotoxicity, whereas GNPs were found to be nontoxic to mouse fibroblast cell line (L929) as evident from MTT and acridine orange/ethidium bromide (AO/EtBr) live/dead cell assays. The GNP-Amox conjugates demonstrated enhanced broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. Furthermore, in-vitro and in-vivo assays of GNP-Amox revealed potent anti-MRSA activity and improved the survival rate. This indicates the subversion of antibiotic resistance mechanism by overcoming the effect of high levels of β-lactamase produced by methicillin resistant Staphylococcus aureus (MRSA). Taken together, this study demonstrates the positive attributes from GNP-Amox conjugates as a promising antibacterial therapeutic agent against MRSA as well as other pathogens. - Highlights: • Aqueous extract of A. phillippens was used as a reducing and capping agent for synthesis of microwave irradiated gold nanoparticles. • GNPs were loaded with amoxicillin for restoration in antibacterial activity of amoxicillin against MRSA strains. • Gold nanoparticles and GNP-Amox were found biocompitable as tested on L929 cell line. • The nanoparticle antibiotic conjugates exhibited restoration of amoxicillin activity against MRSA in

  2. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Energy Technology Data Exchange (ETDEWEB)

    Mahl, Dirk; Diendorf, Joerg; Ristig, Simon [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Greulich, Christina [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Li Zian; Farle, Michael [University of Duisburg-Essen, Faculty of Physics, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Koeller, Manfred [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2012-10-15

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 {mu}g mL{sup -1} induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  3. Functionalization of gold nanoparticles and CdS quantum dots with cell penetrating peptides

    Science.gov (United States)

    Berry, Catherine C.; de la Fuente, Jesus M.

    2009-02-01

    During the last decade, there has been great deal of interest in the self-assembly fabrication of hybrid materials from inorganic nanoparticles and biomolecules. Nanoparticles are similar in size range to many common biomolecules, thus, nanoparticles appear to be natural companions in hybrid systems. At present, it is straightforward to control and modify properties of nanostructures to better suit their integration with biological systems; for example, controlling their size, modifying their surface layer for enhanced aqueous solubility, biocompatibility, or biorecognition. A particularly desirable target for therapeutic uses is the cell nucleus, because the genetic information is there. We review in this article the synthesis developed by our research group of water-soluble gold nanoparticles and CdS nanocrystals functionalized with a Tat protein-derived peptide sequence by straightforward and economical methodologies. The particles were subsequently tested in vitro with a human fibroblast cell line using optical and transmission electron microscopy to determine the biocompatibility of these nanoparticles and whether the functionalization with the cell penetrating peptide allowed particles to transfer across the cell membrane and locate into the nucleus.

  4. Biosynthesis and Application of Silver and Gold Nanoparticles

    OpenAIRE

    Sadowski, Zygmunt

    2010-01-01

    A green chemistry synthetic route has been used for both silver and gold nanoparticles synthesis. The reaction occurred at ambient temperature. Among the nanoparticles biological organism, some microorganisms such as bacteria, fungi, and yeast have been exploited for nanoparticles synthesis. Several plant biomass or plant extracts have been successfully used for extracellular biosynthesis of silver and gold nanoparticles. Analytical techniques, such as ultraviolet-visible spectroscopy (UV-vis...

  5. Synthesis of gold nanoparticles and silver nanoparticles via green technology

    Science.gov (United States)

    Ahmed, Zulfiqaar; Balu, S. S.

    2012-11-01

    The proposed work describes the comparison of various methods of green synthesis for preparation of Gold and Silver nanoparticles. Pure extracts of Lemon (Citrus limon) and Tomato (Solanum lycopersicum) were mixed with aqueous solution of auric tetrachloride and silver nitrate. The resultant solutions were treated with four common techniques to assist in the reduction namely photo catalytic, thermal, microwave assisted reduction and solvo - thermal reduction. UV - Visible Spectroscopy results and STM images of the final solutions confirmed the formation of stable metallic nanoparticles. A preliminary account of the green synthesis work is presented here.

  6. Aggregation effect on absorbance spectrum of laser ablated gold nanoparticles

    Science.gov (United States)

    Isnaeni; Irmaniar; Herbani, Y.

    2017-04-01

    Plasmon of gold nanoparticles is one of the hot topics nowadays due to various possible applications. The application is determined by plasmon peak in absorbance spectrum. We have fabricated gold nanoparticles using laser ablation technique and studied the influence of CTAB (Cetyl trimethylammonium bromide) effect on the optical characterization of fabricated gold nanoparticles. We ablated a gold plate using NdYAG pulsed laser at 1064 nm wavelength, 10 Hz pulse frequency at low energy density. We found there are two distinctive plasmon peaks, i.e., primary and secondary peaks, where the secondary peak is the main interests of this work. Our simulation results have revealed that the secondary plasmon peak is affected by random aggregation of gold nanoparticles. Our research leads to good techniques on fabrication of colloidal gold nanoparticles in aqueous solution using laser ablation technique.

  7. Self-assembly of chiral fluorescent nanoparticles based on water-soluble L-tryptophan derivatives of p-tert-butylthiacalix[4]arene

    Directory of Open Access Journals (Sweden)

    Pavel L. Padnya

    2017-09-01

    Full Text Available New water-soluble tetra-substituted derivatives of p-tert-butylthiacalix[4]arene containing fragments of L-tryptophan in cone and 1,3-alternate conformations were obtained. It was shown that the resulting compounds form stable, positively charged aggregates of 86–134 nm in diameter in water at a concentration of 1 × 10−4 M as confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. It was established that these aggregates are fluorescently active and chiral. A distinctive feature of the compounds is the pronounced dependence of their spectral (emission and chiroptical properties on the polarity of the solvent and the length of the linker between the macrocyclic and fluorophore parts of the molecule.

  8. Self-assembly of chiral fluorescent nanoparticles based on water-soluble L-tryptophan derivatives of p-tert-butylthiacalix[4]arene.

    Science.gov (United States)

    Padnya, Pavel L; Khripunova, Irina A; Mostovaya, Olga A; Mukhametzyanov, Timur A; Evtugyn, Vladimir G; Vorobev, Vyacheslav V; Osin, Yuri N; Stoikov, Ivan I

    2017-01-01

    New water-soluble tetra-substituted derivatives of p-tert-butylthiacalix[4]arene containing fragments of L-tryptophan in cone and 1,3-alternate conformations were obtained. It was shown that the resulting compounds form stable, positively charged aggregates of 86-134 nm in diameter in water at a concentration of 1 × 10-4 M as confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. It was established that these aggregates are fluorescently active and chiral. A distinctive feature of the compounds is the pronounced dependence of their spectral (emission and chiroptical) properties on the polarity of the solvent and the length of the linker between the macrocyclic and fluorophore parts of the molecule.

  9. Interaction of gold nanoparticles with nanosecond laser pulses: Nanoparticle heating

    Energy Technology Data Exchange (ETDEWEB)

    Nedyalkov, N.N., E-mail: nnn_1900@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, Tzarigradsko shousse 72, Sofia 1784 (Bulgaria); Imamova, S.E.; Atanasov, P.A. [Institute of Electronics, Bulgarian Academy of Sciences, Tzarigradsko shousse 72, Sofia 1784 (Bulgaria); Toshkova, R.A.; Gardeva, E.G.; Yossifova, L.S.; Alexandrov, M.T. [Institute of Experimental Pathology and Parasitology, Bulgarian Academy of Sciences, G. Bonchev Street, bl. 25, Sofia 1113 (Bulgaria); Obara, M. [Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2011-04-01

    Theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. The efficiency of particle heating is demonstrated by in-vitro photothermal therapy of human tumor cells. Gold nanoparticles with diameters of 40 and 100 nm are added as colloid in the cell culture and the samples are irradiated by nanosecond pulses at wavelength of 532 nm delivered by Nd:YAG laser system. The results indicate clear cytotoxic effect of application of nanoparticle as more efficient is the case of using particles with diameter of 100 nm. The theoretical analysis of the heating process of nanoparticle interacting with laser radiation is based on the Mie scattering theory, which is used for calculation of the particle absorption coefficient, and two-dimensional heat diffusion model, which describes the particle and the surrounding medium temperature evolution. Using this model the dependence of the achieved maximal temperature in the particles on the applied laser fluence and time evolution of the particle temperature is obtained.

  10. Green Chemistry Techniques for Gold Nanoparticles Synthesis

    Science.gov (United States)

    Cannavino, Sarah A.; King, Christy A.; Ferrara, Davon W.

    Gold nanoparticles (AuNPs) are often utilized in many technological and research applications ranging from the detection of tumors, molecular and biological sensors, and as nanoantennas to probe physical processes. As these applications move from the research laboratory to industrial settings, there is a need to develop efficient and sustainable synthesis techniques. Recent research has shown that several food products and beverages containing polyphenols, a common antioxidant, can be used as reducing agents in the synthesis of AuNPs in solution. In this study, we explore a variety of products to determine which allow for the most reproducible solution of nanoparticles based on the size and shapes of particles present. We analyzed the AuNPs solutions using extinction spectroscopy and atomic force microscopy. We also develop a laboratory activity to introduce introductory chemistry and physics students to AuNP synthesis techniques and analysis.

  11. Advances in cancer research using gold nanoparticles mediated photothermal ablation.

    Science.gov (United States)

    Mocan, Lucian; Matea, Cristian T; Bartos, Dana; Mosteanu, Ofelia; Pop, Teodora; Mocan, Teodora; Iancu, Cornel

    2016-01-01

    Recent research suggests that nanotechnologies may lead to the development of novel cancer treatment. Gold nanoparticles with their unique physical and chemical properties hold great hopes for the development of thermal-based therapies against human malignancies. This review will focus on various strategies that have been developed to use gold nanoparticles as photothermal agents against human cancers.

  12. Multifunctional gold nanoparticles for diagnosis and therapy of disease

    NARCIS (Netherlands)

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

    2013-01-01

    Gold nanoparticles (AuNPs) have a number of physical properties that make them appealing for medical applications. For example, the attenuation of X-rays by gold nanoparticles has led to their use in computed tomography imaging and as adjuvants for radiotherapy. AuNPs have numerous other

  13. Undergraduate Laboratory Experiment Modules for Probing Gold Nanoparticle Interfacial Phenomena

    Science.gov (United States)

    Karunanayake, Akila G.; Gunatilake, Sameera R.; Ameer, Fathima S.; Gadogbe, Manuel; Smith, Laura; Mlsna, Deb; Zhang, Dongmao

    2015-01-01

    Three gold-nanoparticle (AuNP) undergraduate experiment modules that are focused on nanoparticles interfacial phenomena have been developed. Modules 1 and 2 explore the synthesis and characterization of AuNPs of different sizes but with the same total gold mass. These experiments enable students to determine how particle size affects the AuNP…

  14. Functionalized Gold Nanoparticles: Synthesis, Properties and Applications--A Review.

    Science.gov (United States)

    Alex, Saji; Tiwari, Ashutosh

    2015-03-01

    The past few decades have witnessed significant advances in the development of functionalized gold nanoparticles for applications in various fields such as chemistry, biology, pharmacy and physics. Although it has been more than 150 years since they were first synthesized, extensive research has recently been undertaken to improve or modify gold nanoparticles, thereby opening up opportunities to enhance and optimize their potential and breadth of their applicability. Recently developed methods have allowed a precise control of gold nanoparticle size and the modification of gold nanoparticles with suitable protecting and functionalizing agents, facilitate their applications in different areas such as chemical and biological sensing, imaging and biomedical applications. This review focuses on the recent developments in various methods for the size and shape controlled synthesis of gold nanoparticles, understanding of different properties of gold nanoparticles and their applications in various fields. Particular attention is given to the chemical and biological sensing applications of gold nanoparticles and on the advances in the controlled ordering of gold nanoparticles for creating nanostructures for diverse applications.

  15. Preparation of Gold Nanoparticles for Biomedical Applications Using ...

    African Journals Online (AJOL)

    HP

    7. Cai W, Gao T, Hong H, Sun J, Applications of gold nanoparticles in cancer nanotechnology,. Nanotechnology, 2008; 1: 17-32. 8. Sonavane G, Tomada K, Sano A, Ohshima H, Terada. H, Makino K, Invitro permeation of gold nanoparticles through rat akin and rat intestine: effect of particle size, colloid surface B 2008; 65: 1-.

  16. Facially amphiphilic thiol capped gold and silver nanoparticles

    Indian Academy of Sciences (India)

    Wintec

    Generally, gold nanoparticles are easily produced in a liquid ('liquid chemical methods') by the reduction of chloroauric acid (HAuCl4), although more advanced and precise methods exist. As the neutral gold atoms form, the solution becomes su- persaturated, and gold gradually starts to precipitate in the form of ...

  17. Instant and supersaturated dissolution of naproxen and sesamin (poorly water-soluble drugs and supplements) nanoparticles prepared by continuous expansion of liquid carbon dioxide solution through long dielectric nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Arita, Toshihiko, E-mail: tarita@tagen.tohoku.ac.jp [Tohoku University, Institute of Multidisciplinary Research for Advanced Materials (Japan); Manabe, Noriyoshi [Tohoku University, Graduate School of Engineering (Japan); Nakahara, Koichi [Suntory Bussiness Expert Limited, Frontier Center for Value Creation (Japan)

    2012-11-15

    Nanoparticles (NPs) of naproxen (a nonsteroidal anti-inflammatory drug, BCS Class 2) and sesamin (a poorly water-soluble lignan) were investigated. By applying a newly developed rapid expansion system of liquid carbon dioxide solutions equipped with a dielectric nozzle, well-separated and fine both naproxen NPs (averaged particle size (APS) = 46.9 nm) and sesamin NPs (APS = 60.2 nm) were obtained without heating, surfactants, and co-solvents. Obtained naproxen and sesamin NPs had large surface/weight ratio, therefore, they showed instant dissolution to water until about ten percent higher than the saturated concentrations. In addition, the technique developed in the study has big advantage on producing especially drug NPs because the NPs produced by the method never includes neither poisonous additives (especially co-solvents and detergents) nor thermally denatured compounds.

  18. Thermal stability of DNA functionalized gold nanoparticles.

    Science.gov (United States)

    Li, Feng; Zhang, Hongquan; Dever, Brittany; Li, Xing-Fang; Le, X Chris

    2013-11-20

    Therapeutic uses of DNA functionalized gold nanoparticles (DNA-AuNPs) have shown great potential and exciting opportunities for disease diagnostics and treatment. Maintaining stable conjugation between DNA oligonucleotides and gold nanoparticles under thermally stressed conditions is one of the critical aspects for any of the practical applications. We systematically studied the thermal stability of DNA-AuNPs as affected by organosulfur anchor groups and packing densities. Using a fluorescence assay to determine the kinetics of releasing DNA molecules from DNA-AuNPs, we observed an opposite trend between the temperature-induced and chemical-induced release of DNA from DNA-AuNPs when comparing the DNA-AuNPs that were constructed with different anchor groups. Specifically, the bidentate Au-S bond formed with cyclic disulfide was thermally less stable than those formed with thiol or acyclic disulfide. However, the same bidentate Au-S bond was chemically more stable under the treatment of competing thiols (mercaptohexanol or dithiothreitol). DNA packing density on AuNPs influenced the thermal stability of DNA-AuNPs at 37 °C, but this effect was minimum as temperature increased to 85 °C. With the improved understanding from these results, we were able to design a strategy to enhance the stability of DNA-AuNPs by conjugating double-stranded DNA to AuNPs through multiple thiol anchors.

  19. Seed-mediated growth of jack-shaped gold nanoparticles from cyclodextrin-coated gold nanospheres.

    Science.gov (United States)

    Sánchez, Alfredo; Díez, Paula; Villalonga, Reynaldo; Martínez-Ruiz, Paloma; Eguílaz, Marcos; Fernández, Iñigo; Pingarrón, José M

    2013-10-21

    Branched gold nanoparticles were prepared by a seed-mediated approach using per-6-thio-6-deoxy-β-cyclodextrin capped gold nanospheres as seeds and a growth medium similar to those commonly employed to prepare gold nanorods, containing AgNO3, ascorbic acid and cetyltrimethylammonium bromide. Novel jack-shaped gold nanoparticles (102-105 nm) were obtained at a specific range of Ag(+) ion concentrations (62-102 μM). The crystalline structure of these nanoparticles was confirmed by high-resolution transmission electron microscopy. The influence of the perthiolated β-cyclodextrin on the successful preparation of gold nanojacks was demonstrated. The jack-shaped gold nanoparticles showed strong absorption in the near infrared region and excellent catalytic activity for the electrochemical oxidation of H2O2.

  20. Green synthesis of gold nanoparticles using Cinnamomum zeylanicum leaf broth

    Science.gov (United States)

    Smitha, S. L.; Philip, Daizy; Gopchandran, K. G.

    2009-10-01

    Development of biologically inspired experimental processes for the synthesis of nanoparticles is an important branch of nanotechnology. The synthesis of gold nanoparticles using Cinnamomum zeylanicum leaf broth as the reducing agent is reported. The morphology of the particles formed consists of a mixture of gold nanoprisms and spheres with fcc (1 1 1) structure of gold. At lower concentrations of the extract, formation of prism shaped Au particles dominates, while at higher concentrations almost spherical particles alone are observed. Good crystallinity of the nanoparticles with fcc phase is evident from XRD patterns, clear lattice fringes in the high resolution TEM image and bright circular rings in the SAED pattern. Au nanoparticles grown are observed to be photoluminescent and the intensity of photoemission is found to increase with increase in leaf broth concentration. The ability to modulate the shape of nanoparticles as observed in this study for gold nanoparticles opens up the exciting possibility of developing further synthetic routes employing ecofriendly sources.

  1. Microbial synthesis of Flower-shaped gold nanoparticles.

    Science.gov (United States)

    Singh, Priyanka; Kim, Yeon Ju; Wang, Chao; Mathiyalagan, Ramya; Yang, Deok Chun

    2016-09-01

    The shape of nanoparticles has been recognized as an important attribute that determines their applicability in various fields. The flower shape (F-shape) has been considered and is being focused on, because of its enhanced properties when compared to the properties of the spherical shape. The present study proposed the microbial synthesis of F-shaped gold nanoparticles within 48 h using the Bhargavaea indica DC1 strain. The F-shaped gold nanoparticles were synthesized extracellularly by the reduction of auric acid in the culture supernatant of B. indica DC1. The shape, size, purity, and crystalline nature of F-shaped gold nanoparticles were revealed by various instrumental techniques including UV-Vis, FE-TEM, EDX, elemental mapping, XRD, and DLS. The UV-Vis absorbance showed a maximum peak at 536 nm. FE-TEM revealed the F-shaped structure of nanoparticles. The EDX peak obtained at 2.3 keV indicated the purity. The peaks obtained on XRD analysis corresponded to the crystalline nature of the gold nanoparticles. In addition, the results of elemental mapping indicated the maximum distribution of gold elements in the nanoproduct obtained. Particle size analysis revealed that the average diameter of the F-shaped gold nanoparticles was 106 nm, with a polydispersity index (PDI) of 0.178. Thus, the methodology developed for the synthesis of F-shaped gold nanoparticles is completely green and economical.

  2. Monodisperse magnetite (Fe{sub 3}O{sub 4}) nanoparticles modified with water soluble polymers for the diagnosis of breast cancer by MRI method

    Energy Technology Data Exchange (ETDEWEB)

    Rezayan, Ali Hossein, E-mail: ahrezayan@ut.ac.ir [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran (Iran, Islamic Republic of); Mousavi, Majid [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran (Iran, Islamic Republic of); Kheirjou, Somayyeh [Department of Chemistry, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Amoabediny, Ghasem [School of Chemical Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Ardestani, Mehdi Shafiee [Department of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mohammadnejad, Javad [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran (Iran, Islamic Republic of)

    2016-12-15

    In this study, magnetic nanoparticles (MNPs) were synthesized via co-precipitation method. To enhance the biocompatibility and colloidal stability of the synthesized nanoparticles, they were modified with carboxyl functionalized PEG via dopamine (DPA) linker. Both modified and unmodified Fe{sub 3}O{sub 4} nanoparticles exhibited super paramagnetic behavior (particle size below 20 nm). The saturation magnetization (Ms) of PEGdiacid-modified Fe{sub 3}O{sub 4} was 45 emu/g, which was less than the unmodified Fe{sub 3}O{sub 4} nanoparticles (70 emu/g). This difference indicated that PEGdiacid polymer was immobilized on the surface of Fe{sub 3}O{sub 4} nanoparticles successfully. To evaluate the efficiency of the resulting nanoparticles as contrast agents for magnetic resonance imaging (MRI), different concentration of MNPs and different value of echo time TE were investigated. The results showed that by increasing the concentration of the nanoparticles, transverse relaxation time (T{sub 2}) decreased, which subsequently resulted in MR signal enhancement. T{sub 2}-weighted MR images of the different concentration of MNPs in different value of echo time TE indicated that MR signal intensity increased with increase in TE value up to 66 and then remained constant. The cytotoxicity effect of the modified and unmodified nanoparticles was evaluated in three different concentrations (12, 60 and 312 mg l{sup −1}) on MDA-MB-231 cancer cells for 24 and 48 h. In both tested time (24 and 48 h) for all three samples, the modified nanoparticles had long life time than unmodified nanoparticles. Cellular uptake of modified MNPs was 80% and reduced to 9% by the unmodified MNPs. - Highlights: • Magnetic nanoparticles (MNPs) were synthesized via co-precipitation method. • MNPs were modified with carboxyl functionalized PEG via dopamine (DPA) linker. • Modified and unmodified Fe{sub 3}O{sub 4} nanoparticles exhibited super paramagnetic behavior. • T{sub 2} decrease as MNPs

  3. Water-Soluble Nanodiamond (Postprint)

    Science.gov (United States)

    2012-03-01

    nanodiamond salt that reacts with either alkyl or aryl halides by electron transfer to yield radical anions that dissociate spontaneously into free radicals...sodium in liquid ammonia leads to the nanodiamond salt 1. This material can be reacted with either alkyl or aryl halides to yield a radical anion that...From - To) March 2012 Technical Paper 1 October 2008 – 1 March 2012 4. TITLE AND SUBTITLE WATER-SOLUBLE NANODIAMOND (POSTPRINT) 5a. CONTRACT

  4. Temperature driven transport of gold nanoparticles physisorbed inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, P.A.E.; Poulikakos, D.; Walther, Jens Honore

    2006-01-01

    We use molecular dynamics simulations to demonstrate the temperature driven mass transport of solid gold nanoparticles, physisorbed inside carbon nanotubes (CNTs). Our results indicate that the nanoparticle experiences a guided motion, in the direction opposite to the direction of the temperature...... affects the nanoparticle motion along the carbon lattice....

  5. Phonon assisted thermophoretic motion of gold nanoparticles inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, Philipp A.E.; Walther, Jens Honore; Poulikakos, Dimos

    2007-01-01

    , in particular, with the breathing mode of the tube. Additionally, the results show an increased static friction for gold nanoparticles confines inside a zig-zag carbon nanotube when increasing the size length of the nanoparticles. However, an unexpected, opposite trend is observed for the same nanoparticles...

  6. Monodisperse magnetite (Fe3O4) nanoparticles modified with water soluble polymers for the diagnosis of breast cancer by MRI method

    Science.gov (United States)

    Rezayan, Ali Hossein; Mousavi, Majid; Kheirjou, Somayyeh; Amoabediny, Ghasem; Ardestani, Mehdi Shafiee; Mohammadnejad, Javad

    2016-12-01

    In this study, magnetic nanoparticles (MNPs) were synthesized via co-precipitation method. To enhance the biocompatibility and colloidal stability of the synthesized nanoparticles, they were modified with carboxyl functionalized PEG via dopamine (DPA) linker. Both modified and unmodified Fe3O4 nanoparticles exhibited super paramagnetic behavior (particle size below 20 nm). The saturation magnetization (Ms) of PEGdiacid-modified Fe3O4 was 45 emu/g, which was less than the unmodified Fe3O4 nanoparticles (70 emu/g). This difference indicated that PEGdiacid polymer was immobilized on the surface of Fe3O4 nanoparticles successfully. To evaluate the efficiency of the resulting nanoparticles as contrast agents for magnetic resonance imaging (MRI), different concentration of MNPs and different value of echo time TE were investigated. The results showed that by increasing the concentration of the nanoparticles, transverse relaxation time (T2) decreased, which subsequently resulted in MR signal enhancement. T2-weighted MR images of the different concentration of MNPs in different value of echo time TE indicated that MR signal intensity increased with increase in TE value up to 66 and then remained constant. The cytotoxicity effect of the modified and unmodified nanoparticles was evaluated in three different concentrations (12, 60 and 312 mg l-1) on MDA-MB-231 cancer cells for 24 and 48 h. In both tested time (24 and 48 h) for all three samples, the modified nanoparticles had long life time than unmodified nanoparticles. Cellular uptake of modified MNPs was 80% and reduced to 9% by the unmodified MNPs.

  7. Versatile Methodology to Encapsulate Gold Nanoparticles in PLGA Nanoparticles Obtained by Nano-Emulsion Templating.

    Science.gov (United States)

    Fornaguera, Cristina; Feiner-Gracia, Natàlia; Dols-Perez, Aurora; García-Celma, Maria José; Solans, Conxita

    2017-05-01

    Gold nanoparticles have been proved useful for many biomedical applications, specifically, for their use as advanced imaging systems. However, they usually present problems related with stability and toxicity. In the present work, gold-nanoparticles have been encapsulated in polymeric nanoparticles using a novel methodology based on nano-emulsion templating. Firstly, gold nanoparticles have been transferred from water to ethyl acetate, a solvent classified as class III by the NIH guidelines (low toxic potential). Next, the formation of nano-emulsions loaded with gold nanoparticles has been performed using a low-energy, the phase inversion composition (PIC) emulsification method, followed by solvent evaporation giving rise to polymeric nanoparticles. Using this methodology, high concentrations of gold nanoparticles (>100 pM) have been encapsulated. Increasing gold nanoparticle concentration, nano-emulsion and nanoparticle sizes increase, resulting in a decrease on the stability. It is noteworthy that the designed nanoparticles did not produce cytotoxicity neither hemolysis at the required concentration. Therefore, it can be concluded that a novel and very versatile methodology has been developed for the production of polymeric nanoparticles loaded with gold nanoparticles. Graphical Abstract Schematic representation of AuNP-loaded polymeric nanoparticles preparation from nano-emulsion templating.

  8. Dithizone modified gold nanoparticles films for potentiometric sensing.

    Science.gov (United States)

    Woźnica, Emilia; Wójcik, Michał M; Wojciechowski, Marcin; Mieczkowski, Józef; Bulska, Ewa; Maksymiuk, Krzysztof; Michalska, Agata

    2012-05-15

    For the first time, application of a membrane composed of gold nanoparticles decorated with complexing ligand for potentiometric sensing is shown. Gold nanoparticles drop cast from a solution form a porous structure on a substrate electrode surface. Sample cations can penetrate the gold nanoparticles layer and interact with ligand acting as a charged ionophore, resulting in Nernstian potentiometric responses. Anchoring of complexing ligand on the gold surface abolishes the necessity of ionophore application. Moreover, it opens the possibility of preparation of potentiometric sensors using chelators of significantly different selectivity patterns further enhanced by the absence of polymeric membrane matrix. This was clearly seen, for example, for gold nanoparticles stabilizing the applied ligand-dithizone-thiol conformation leading to a high potentiometric selectivity toward copper ions, much higher than that of ionophores typically used to induce selectivity for polymeric ion-selective membranes.

  9. Pseudo-template synthesis of gold nanoparticles based on polyhydrosilanes

    Energy Technology Data Exchange (ETDEWEB)

    Sacarescu, Liviu, E-mail: livius@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, Iasi 700487 (Romania); Simionescu, Mihaela; Sacarescu, Gabriela [Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, Iasi 700487 (Romania)

    2011-02-01

    Highly stable colloidal gold nanoparticles are obtained in a pseudo-template system using a specific polyhydrosilane copolymeric structure. This process takes place in situ by microwaves activation of the polymer solution in a non-polar solvent followed by stirring with solid HAuCl{sub 4} in natural light. The experimental procedure is very simple and the resulted colloidal gold solution is indefinitely stable. The specific surface plasmon resonance absorption band of the gold nanoparticles is strongly red shifted and is strictly related to their size. AFM correlated with DLS analysis showed flattened round shaped colloidal polymer-gold nanoparticles with large diameters. SEM-EDX combined analysis reveals that the polysilane-gold nanoparticles show a natural tendency to auto-assemble in close packed structures which form large areas over the polymer film surface.

  10. Biodistribution of gold nanoparticles in mouse lung following intratracheal instillation

    Directory of Open Access Journals (Sweden)

    Vogel Ulla

    2009-11-01

    Full Text Available Abstract Background The fate of gold nanoparticles, 2, 40 and 100 nm, administered intratracheally to adult female mice was examined. The nanoparticles were traced by autometallography (AMG at both ultrastructural and light microscopic levels. Also, the gold content was quantified by inductively coupled plasma mass spectrometry (ICP-MS and neutron activation analysis (NAA. The liver is the major site of deposition of circulating gold nanoparticles. Therefore the degree of translocation was determined by the hepatic deposition of gold. Mice were instilled with 5 intratracheal doses of gold nanoparticles distributed over a period of 3 weeks and were killed 24 h after the last dose. One group of mice were given a single intratracheal dose and were killed after 1 h. Results The instilled nanoparticles were found in lung macrophages already 1 h after a single instillation. In mice instilled treated repeatedly during 3 weeks, the load was substantial. Ultrastructurally, AMG silver enhanced gold nanoparticles were found in lysosome-/endosome-like organelles of the macrophages and analysis with AMG, ICP-MS and NAA of the liver revealed an almost total lack of translocation of nanoparticles. In mice given repeated instillations of 2 nm gold nanoparticles, 1.4‰ (by ICP-MS to 1.9‰ (by NAA of the instilled gold was detected in the liver. With the 40 nm gold, no gold was detected in the liver (detection level 2 ng, 0.1‰ except for one mouse in which 3‰ of the instilled gold was found in the liver. No gold was detected in any liver of mice instilled with 100 nm gold (detection level 2 ng, 0.1‰ except in a single animal with 0.39‰ of the dose in the liver. Conclusion We found that that: (1 inert gold nanoparticles, administered intratracheally are phagocytosed by lung macrophages; (2 only a tiny fraction of the gold particles is translocated into systemic circulation. (3 The translocation rate was greatest with the 2 nm gold particles.

  11. GOLD NANOPARTICLES: A REVIVAL IN PRECIOUS METAL ADMINISTRATION TO PATIENTS

    Science.gov (United States)

    Thakor, AS; Jokerst, J; Zaveleta, C; Massoud, TF; Gambhir, SS

    2011-01-01

    Gold has been used as a therapeutic agent to treat a wide variety of rheumatic diseases including psoriatic arthritis, juvenile arthritis and discoid lupus erythematosus. Although the use of gold has been largely superseded by newer drugs, gold nanoparticles are being used effectively in laboratory based clinical diagnostic methods whilst concurrently showing great promise in vivo either as a diagnostic imaging agent or a therapeutic agent. For these reasons, gold nanoparticles are therefore well placed to enter mainstream clinical practice in the near future. Hence, the present review summarizes the chemistry, pharmacokinetics, bio-distribution, metabolism and toxicity of bulk gold in humans based on decades of clinical observation and experiments in which gold was used to treat patients with rheumatoid arthritis. The beneficial attributes of gold nanoparticles, such as their ease of synthesis, functionalization and shape control are also highlighted demonstrating why gold nanoparticles are an attractive target for further development and optimization. The importance of controlling the size and shape of gold nanoparticles to minimize any potential toxic side effects is also discussed. PMID:21846107

  12. Multifunctional gold nanoparticles for diagnosis and therapy of disease

    Science.gov (United States)

    Mieszawska, Aneta J.; Mulder, Willem J. M.; Fayad, Zahi A.

    2013-01-01

    Gold nanoparticles (AuNPs) have a number of physical properties that make them appealing for medical applications. For example, the attenuation of X-rays by gold nanoparticles has led to their use in computed tomography imaging and as adjuvants for radiotherapy. AuNPs have numerous other applications in imaging, therapy and diagnostic systems. The advanced state of synthetic chemistry of gold nanoparticles offers precise control over physicochemical and optical properties. Furthermore gold cores are inert and are considered to be biocompatible and non-toxic. The surface of gold nanoparticles can easily be modified for a specific application and ligands for targeting, drugs or biocompatible coatings can be introduced. AuNPs can be incorporated into larger structures such as polymeric nanoparticles or liposomes that deliver large payloads for enhanced diagnostic applications, efficiently encapsulate drugs for concurrent therapy or add additional imaging labels. This array of features has led to the afore-mentioned applications in biomedical fields, but more recently in approaches where multifunctional gold nanoparticles are used for multiple methods, such as concurrent diagnosis and therapy, so called theranostics. The following review covers basic principles and recent findings in gold nanoparticle applications for imaging, therapy and diagnostics, with a focus on reports of multifunctional AuNPs. PMID:23360440

  13. Gold revolution--gold nanoparticles for modern medicine and surgery.

    Science.gov (United States)

    Rippel, Radoslaw A; Seifalian, Alexander M

    2011-05-01

    Nanotechnology is a new and exciting branch of science which offers enormous potential for development of medicine and surgery. Gold nanoparticles (GNP) is just one of a variety of nano products which will be available for physician of the future. GNP will give us more effective treatments and diagnosis. We are able to conjugate GNP with peptides, drugs, and other molecules to gain astonishing effects. High quality, non-invasive imaging will inevitably lead to astonishing accuracy diagnostic tools with effective use during surgery. The same principles may be used in the future for drug delivery and thermal treatment of cancer. Detailed DNA detection and regulation may become everyday use technology, in medicine with support from GNP based tools. Bacterial diagnostics and nerve repair are relatively poorly researched areas of application of GNP with possibly astonishing therapeutic effects. Non-invasive clearance of arteriosclerotic plagues with GNP shows a great prospect for further development of minimally invasive surgery. However, before all of those tools will become available for clinicians, in depth toxicology research as well as transitional research and design have to be done to ensure safe clinical practice with maximal benefit for patients.

  14. Application of gold nanoparticles in biomedical and drug delivery.

    Science.gov (United States)

    Daraee, Hadis; Eatemadi, Ali; Abbasi, Elham; Fekri Aval, Sedigheh; Kouhi, Mohammad; Akbarzadeh, Abolfazl

    2016-01-01

    Nanoparticles are the simplest form of structures with sizes in the nanometer (nm) range. In principle any collection of atoms bonded together with a structural radius of nanoparticles offer some unique advantages as sensing, image enhancement, and delivery agents. Several varieties of nanoparticles with biomedical relevance are available including, polymeric nanoparticles, metal nanoparticles, liposomes, micelles, quantum dots, dendrimers, and nanoassemblies. To further the application of nanoparticles in disease diagnosis and therapy, it is important that the systems are biocompatible and capable of being functionalized for recognition of specific target sites in the body after systemic administration. In this review, we have explained some important applications of gold nanoparticles.

  15. Green Synthesis of Gold Nanoparticles by a Metal Resistant Arthrobacter nitroguajacolicus Isolated From Gold Mine.

    Science.gov (United States)

    Dehnad, Alireza; Hamedi, Javad; Derakhshan-Khadivi, Fatemeh; Abusov, Rahib

    2015-06-01

    Biosynthesis of gold nanoparticles would benefit from the development of clean, nontoxic and environmentally acceptable procedures concerning microorganisms from bacteria to fungi and even algae. Actinobacteria are soil bacteria which have the enormous ability as biotechnological tools. In this paper, we reported the biosynthesis of gold nanoparticles by a member of Arthrobacter genus isolated from Andaliyan gold mine in north-west of Iran. This metal resistance strain obtained from an acidophilic region ( ~ pH 5.6). The UV-vis and XRD spectra of the aqueous medium containing the strain and 1 mM HAuCl 4 for 24 h, demonstrated the formation of gold nanoparticles. TEM micrographs showed intra-extracellular production of gold nanoparticles with spherical shape and average size of 40 nm. The result of morphological and molecular tests revealed that the isolate was belonged to Atrhrobacter and has 100% similarity in 16SrRNA gene sequences to Arthrobacter nitroguajacolicus.

  16. Optical frequency mixing at coupled gold nanoparticles.

    Science.gov (United States)

    Danckwerts, Matthias; Novotny, Lukas

    2007-01-12

    We present nonlinear-optical four-wave mixing (4WM) at coupled gold nanoparticles. By decreasing the interparticle distance from large separation to touching contact, the 4WM yield increases by 4 orders of magnitude. The reason for this dramatic enhancement lies in the shift of the localized plasmon resonance to infrared wavelengths as the dimer is formed, making one of the input wavelengths doubly resonant. At the touching point, the 4WM signal changes discontinuously because of a sudden charge redistribution imposed by the formation of a conductive bridge. The 4-wave mixing signal provides an ultrasensitive measure for the contact point between a pair of particles and it can be employed as a spatially and temporally controllable photon source.

  17. Application of gold nanoparticles in biomedical researches and diagnosis.

    Science.gov (United States)

    Liu, Aibo; Ye, Bin

    2013-01-01

    Gold nanoparticles have been widely used in biomedical research and diagnosis for their good biocompatibility, high surface areas, nontoxic and unique physicochemical properties. This article reviews the applications of gold nanoparticles in the detection of pathogens, proteins, toxic substances, and drug analyses, and in the preparation of biosensors, treatment of disease, and etiological analysis. The application of gold nanoparticles will have broader applications in biomedical research and diagnosis along with a deeper research into AuNPs and more findings in its novel special properties.

  18. Biodistribution of gold nanoparticles following intratracheal instillation in mouse lung

    DEFF Research Database (Denmark)

    Sadauskas, Evaldas; Jacobsen, Nicklas R.; Danscher, Gorm

    2009-01-01

    plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA). The liver is the major site of deposition of circulating gold nanoparticles. Therefore the degree of translocation was determined by the hepatic deposition of gold. Mice were instilled with 5 intratracheal doses of gold...... nanoparticles distributed over a period of 3 weeks and were killed 24 h after the last dose. One group of mice were given a single intratracheal dose and were killed after 1 h. Results The instilled nanoparticles were found in lung macrophages already 1 h after a single instillation. In mice instilled treated...

  19. Infrared light-absorbing gold/gold sulfide nanoparticles induce cell death in esophageal adenocarcinoma

    Science.gov (United States)

    Li, Yan; Gobin, Andre M; Dryden, Gerald W; Kang, Xinqin; Xiao, Deyi; Li, Su Ping; Zhang, Guandong; Martin, Robert CG

    2013-01-01

    Gold nanoparticles and near infrared-absorbing light are each innocuous to tissue but when combined can destroy malignant tissue while leaving healthy tissue unharmed. This study investigated the feasibility of photothermal ablation therapy for esophageal adenocarcinoma using chitosan-coated gold/gold sulfide (CS-GGS) nanoparticles. A rat esophagoduodenal anastomosis model was used for the in vivo ablation study, and three human esophageal cell lines were used to study the response of cancer cells and benign cells to near infrared light after treatment with CS-GGS. The results indicate that both cancerous tissue and cancer cells took up more gold nanoparticles and were completely ablated after exposure to near infrared light. The benign tissue and noncancerous cells showed less uptake of these nanoparticles, and remained viable after exposure to near infrared light. CS-GGS nanoparticles could provide an optimal endoluminal therapeutic option for near infrared light ablation of esophageal cancer. PMID:23818775

  20. Gold Nanoparticle Conjugation Enhances the Antiacanthamoebic Effects of Chlorhexidine.

    Science.gov (United States)

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Anwar, Ayaz; Shah, Muhammad Raza; Khan, Naveed Ahmed

    2015-12-14

    Acanthamoeba keratitis is a serious infection with blinding consequences and often associated with contact lens wear. Early diagnosis, followed by aggressive topical application of drugs, is a prerequisite in successful treatment, but even then prognosis remains poor. Several drugs have shown promise, including chlorhexidine gluconate; however, host cell toxicity at physiologically relevant concentrations remains a challenge. Nanoparticles, subcolloidal structures ranging in size from 10 to 100 nm, are effective drug carriers for enhancing drug potency. The overall aim of the present study was to determine whether conjugation with gold nanoparticles enhances the antiacanthamoebic potential of chlorhexidine. Gold-conjugated chlorhexidine nanoparticles were synthesized. Briefly, gold solution was mixed with chlorhexidine and reduced by adding sodium borohydride, resulting in an intense deep red color, indicative of colloidal gold-conjugated chlorhexidine nanoparticles. The synthesis was confirmed using UV-visible spectrophotometry that shows a plasmon resonance peak of 500 to 550 nm, indicative of gold nanoparticles. Further characterization using matrix-assisted laser desorption ionization-mass spectrometry showed a gold-conjugated chlorhexidine complex at m/z 699 ranging in size from 20 to 100 nm, as determined using atomic force microscopy. To determine the amoebicidal and amoebistatic effects, amoebae were incubated with gold-conjugated chlorhexidine nanoparticles. For controls, amoebae also were incubated with gold and silver nanoparticles alone, chlorhexidine alone, neomycin-conjugated nanoparticles, and neomycin alone. The findings showed that gold-conjugated chlorhexidine nanoparticles exhibited significant amoebicidal and amoebistatic effects at 5 μM. Amoebicidal effects were observed by parasite viability testing using a Trypan blue exclusion assay and flow-cytometric analysis using propidium iodide, while amoebistatic effects were observed using growth

  1. Optical Properties of Linoleic Acid Protected Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ratan Das

    2011-01-01

    Full Text Available Linoleic acid-protected gold nanoparticles have been synthesized through the chemical reduction of tetrachloroaurate ions by ethanol in presence of sodium linoleate. The structure of these nanoparticles is investigated using transmission electron microscopy, which shows that the Au nanoparticles are spherical in shape with a narrow size distribution which ranges from 8 to 15 nm. Colloidal dispersion of gold nanoparticles in cyclohexane exhibits absorption bands in the ultraviolet-visible range due to surface plasmon resonance, with absorption maximum at 530 nm. Fluorescence spectra of gold nanoparticles also show an emission peak at 610 nm when illuminated at 450 nm. UV-Vis spectroscopy reveals that these nanoparticles remain stable for 10 days.

  2. Biogenic synthesis of gold and silver nanoparticles by seed plants.

    Science.gov (United States)

    Iyer, R Indira; Panda, Tapobrata

    2014-02-01

    Nanoparticles have an enormous range of biomedical and environmental applications and can be used for development of various nanodevices for diagnostics and drug delivery. Biogenic production of nanoparticles, that is of silver and gold, by seed plants, especially flowering plants, has evoked considerable interest in the last decade. Different organs of plants as well as callus cultures have been used for the production of these metal nanoparticles. It is possible to regulate the geometry of the nanoparticles by modifying the experimental parameters. In many cases the phytosynthesized gold and silver nanoparticles have been demonstrated to be potentially useful for treatment of various diseases. The production of gold and silver nanoparticles by diverse species of seed plants and their biological activity are discussed in this article.

  3. Extracellular mycosynthesis of gold nanoparticles using Fusarium solani

    Science.gov (United States)

    Gopinath, K.; Arumugam, A.

    2014-08-01

    The development of eco-friendly methods for the synthesis of nanomaterial shape and size is an important area of research in the field of nanotechnology. The present investigation deals with the extracellular rapid biosynthesis of gold nanoparticles using Fusarium solani culture filtrate. The UV-vis spectra of the fungal culture filtrate medium containing gold ion showed peak at 527 nm corresponding to the plasmon absorbance of gold nanoparticles. FTIR spectra provide an evidence for the presence of heterocyclic compound in the culture filtrate, which increases the stability of the synthesized gold nanoparticles. The X-ray analysis respects the Bragg's law and confirmed the crystalline nature of the gold nanoparticles. AFM analysis showed the results of particle sizes (41 nm). Transmission electron microscopy (TEM) showed that the gold nanoparticles are spherical in shape with the size range from 20 to 50 nm. The use of F. solani will offer several advantages since it is considered as a non-human pathogenic organism. The fungus F. solani has a fast growth rate, rapid capacity of metallic ions reduction, NPs stabilization and facile and economical biomass handling. Extracellular biosynthesis of gold nanoparticles could be highly advantageous from the point of view of synthesis in large quantities, time consumption, eco-friendly, non-toxic and easy downstream processing.

  4. Quantitative detection of gold nanoparticles on individual, unstained cancer cells by Scanning Electron Microscopy

    NARCIS (Netherlands)

    Hartsuiker, Liesbeth; van Es, Peter; Petersen, Wilhelmina; van Leeuwen, Ton; Terstappen, Leonardus Wendelinus Mathias Marie; Otto, Cornelis

    2011-01-01

    Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample

  5. One-step synthesis of monodisperse, water-soluble ultra-small Fe3O4 nanoparticles for potential bio-application

    Science.gov (United States)

    Shen, Li-Hua; Bao, Jian-Feng; Wang, Dong; Wang, Yi-Xiao; Chen, Zhi-Wei; Ren, Lei; Zhou, Xi; Ke, Xue-Bin; Chen, Min; Yang, An-Qi

    2013-02-01

    We report that ultra-small, monodisperse, water-dispersible magnetite (Fe3O4) nanoparticles can be synthesized by a facile one-pot approach using trisodium citrate as crystal grain growth inhibitor and stabilizer in polyol solution. The resultant Fe3O4 nanoparticles exhibit an excellent long-term colloidal stability in various buffer solutions without any modification. They are also superparamagnetic at room temperature and their magnetic property relies heavily on their size. Due to the low magnetization and good water-dispersibility, the 1.9 nm-sized Fe3O4 nanoparticles reveal a low r2/r1 ratio of 2.03 (r1 = 1.415 mM-1 s-1, r2 = 2.87 mM-1 s-1), demonstrating that they can be efficient T1 contrast agents. On the other hand, because of the excellent magnetic responsivity, the 13.8 nm-sized Fe3O4 nanoparticles can be readily modified with nitrilotriacetic acid and used to separate the protein simply with the assistance of a magnet. In addition, these Fe3O4 nanoparticles may be useful in other fields, such as hyperthermia treatment of cancer and targeted drug delivery based on their size-dependent magnetic property and excellent stability.

  6. Structured DNA Aptamer Interactions with Gold Nanoparticles.

    Science.gov (United States)

    Mirau, Peter A; Smith, Joshua E; Chávez, Jorge L; Hagen, Joshua A; Kelley-Loughnane, Nancy; Naik, Rajesh

    2018-02-06

    DNA aptamers that bind biomolecular targets are of interest as the recognition element in colorimetric sensors based on gold nanoparticles (AuNP), where sensor functionality is related to changes in AuNP colloidal stability upon target binding. In order to understand the role of target binding on DNA-AuNP colloidal stability, we have used high-resolution NMR to characterize the interactions of the 36 nucleotide cocaine-binding aptamer (MN4) and related aptamers with AuNPs, cocaine, and cocaine metabolites. Changes in the aptamer imino proton NMR spectra with low (20 nM) concentrations of AuNP show that the aptamers undergo fast-exchange adsorption on the nanoparticle surface. An analysis of the spectral changes and the comparison with modified MN4 aptamers shows that the AuNP binding domain is localized on stem two of the three-stemmed aptamer. The identification of an AuNP recognition domain allows for the incorporation of AuNP binding functionality into a wide variety of aptamers. AuNP-induced spectral changes are not observed for the aptamer-AuNP mixtures in the presence of cocaine, demonstrating that aptamer absorption on the AuNP surface is modulated by aptamer-target interactions. The data also show that the DNA-AuNP interactions and sensor functionality are critically dependent on aptamer folding.

  7. Bayesian object classification of gold nanoparticles

    KAUST Repository

    Konomi, Bledar A.

    2013-06-01

    The properties of materials synthesized with nanoparticles (NPs) are highly correlated to the sizes and shapes of the nanoparticles. The transmission electron microscopy (TEM) imaging technique can be used to measure the morphological characteristics of NPs, which can be simple circles or more complex irregular polygons with varying degrees of scales and sizes. A major difficulty in analyzing the TEM images is the overlapping of objects, having different morphological properties with no specific information about the number of objects present. Furthermore, the objects lying along the boundary render automated image analysis much more difficult. To overcome these challenges, we propose a Bayesian method based on the marked-point process representation of the objects. We derive models, both for the marks which parameterize the morphological aspects and the points which determine the location of the objects. The proposed model is an automatic image segmentation and classification procedure, which simultaneously detects the boundaries and classifies the NPs into one of the predetermined shape families. We execute the inference by sampling the posterior distribution using Markov chainMonte Carlo (MCMC) since the posterior is doubly intractable. We apply our novel method to several TEM imaging samples of gold NPs, producing the needed statistical characterization of their morphology. © Institute of Mathematical Statistics, 2013.

  8. Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Alvarez, S. A. [UASLP, Doctorado Institucional en Ingenieria y Ciencia de Materiales (Mexico); Martinez-Castanon, G. A., E-mail: mtzcastanon@fciencias.uaslp.m [UASLP, Maestria en Ciencias Odontologicas, Facultad de Estomatologia (Mexico); Nino-Martinez, N. [UASLP, Facultad de Ciencias (Mexico); Reyes-Macias, J. F.; Patino-Marin, N.; Loyola-Rodriguez, J. P. [UASLP, Maestria en Ciencias Odontologicas, Facultad de Estomatologia (Mexico); Ruiz, Facundo [UASLP, Facultad de Ciencias (Mexico)

    2010-10-15

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 {mu}g/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

  9. Exploitation of marine bacteria for production of gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Sharma Nishat

    2012-06-01

    Full Text Available Abstract Background Gold nanoparticles (AuNPs have found wide range of applications in electronics, biomedical engineering, and chemistry owing to their exceptional opto-electrical properties. Biological synthesis of gold nanoparticles by using plant extracts and microbes have received profound interest in recent times owing to their potential to produce nanoparticles with varied shape, size and morphology. Marine microorganisms are unique to tolerate high salt concentration and can evade toxicity of different metal ions. However, these marine microbes are not sufficiently explored for their capability of metal nanoparticle synthesis. Although, marine water is one of the richest sources of gold in the nature, however, there is no significant publication regarding utilization of marine micro-organisms to produce gold nanoparticles. Therefore, there might be a possibility of exploring marine bacteria as nanofactories for AuNP biosynthesis. Results In the present study, marine bacteria are exploited towards their capability of gold nanoparticles (AuNPs production. Stable, monodisperse AuNP formation with around 10 nm dimension occur upon exposure of HAuCl4 solution to whole cells of a novel strain of Marinobacter pelagius, as characterized by polyphasic taxonomy. Nanoparticles synthesized are characterized by Transmission electron microscopy, Dynamic light scattering and UV-visible spectroscopy. Conclusion The potential of marine organisms in biosynthesis of AuNPs are still relatively unexplored. Although, there are few reports of gold nanoparticles production using marine sponges and sea weeds however, there is no report on the production of gold nanoparticles using marine bacteria. The present work highlighted the possibility of using the marine bacterial strain of Marinobacter pelagius to achieve a fast rate of nanoparticles synthesis which may be of high interest for future process development of AuNPs. This is the first report of Au

  10. Quinone-Enriched Gold Nanoparticles in Bioelectrochemistry and Charge Storage

    DEFF Research Database (Denmark)

    Wagner, Michal; Qvortrup, Katrine; Tanner, David Ackland

    groups ranging from thiophenes to thiols) were chosen as model compounds for linking together bulk quantities of gold nanoparticles and providing desired functionality. Anthraquinone thiophene and thiol derivatives were synthetized via Sonogashira coupling-type reactions. The synthetic pathways......We are aiming at the development of a general electrochemical platform suitable for multifarious investigations of biogenic materials. The new platform can be attained by grafting organic/metal hybrids with quinone functionality. In-house made and customized anthraquinone derivatives (with linking...... for merging gold nanoparticles with resultant anthraquinones include one-pot microwave assisted synthesis or after-mixing of separately prepared gold nanoparticles with selected compounds. The quinone-enriched gold nanoparticles can be transferred onto different electrode surfaces, thus enabling facile...

  11. A halogen-free synthesis of gold nanoparticles using gold(III) oxide

    Science.gov (United States)

    Sashuk, Volodymyr; Rogaczewski, Konrad

    2016-09-01

    Gold nanoparticles are one of the most used nanomaterials. They are usually synthesized by the reduction of gold(III) chloride. However, the presence of halide ions in the reaction mixture is not always welcome. In some cases, these ions have detrimental influence on the morphology and structure of resulting nanoparticles. Here, we present a simple and halogen-free procedure to prepare gold nanoparticles by reduction of gold(III) oxide in neat oleylamine. The method provides the particles with an average size below 10 nm and dispersity of tens of percent. The process of nanoparticle formation was monitored using UV-Vis spectroscopy. The structure and chemical composition of the nanoparticles was determined by SEM, XPS and EDX. We also proposed the mechanism of reduction of gold(III) oxide based on MS, IR and NMR data. Importantly, the synthetic protocol is general and applicable for the preparation of other coinage metal nanoparticles from the corresponding metal oxides. For instance, we demonstrated that the absence of halogen enables efficient alloying of metals when preparing gold-silver bimetallic nanoparticles.

  12. CHITOSAN-GOLD NANOPARTICLES AS DELIVERY SYSTEMS FOR CURCUMIN

    OpenAIRE

    K. Satish Kumar* D. Gnanaprakash, K. Mayilvaganan, C. Arunraj and S. Mohankumar

    2012-01-01

    The present study deals with investigating the effect of chitosan nano particles as carriers for an anticancer drug curcumin. The chitosan-curcumin nanocapsules were prepared in the presence and absence of gold nanoparticles via solvent evaporation method. Scanning electron microscopy and transmission electron microscopy was done to characterize the drug entrapped nanocapsules. The average diameter of gold nanoparticles was found to be in the range of 18-20 nm and size of the nanocapsules was...

  13. Noninvasive radiofrequency ablation of cancer targeted by gold nanoparticles.

    Science.gov (United States)

    Cardinal, Jon; Klune, John Robert; Chory, Eamon; Jeyabalan, Geetha; Kanzius, John S; Nalesnik, Michael; Geller, David A

    2008-08-01

    Current radiofrequency ablation (RFA) techniques require invasive needle placement and are limited by accuracy of targeting. The purpose of this study was to test a novel non invasive radiowave machine that uses RF energy to thermally destroy tissue. Gold nanoparticles were designed and produced to facilitate tissue heating by the radiowaves. A solid state radiowave machine consisting of a power generator and transmitting/receiving couplers which transmit radiowaves at 13.56 MHz was used. Gold nanoparticles were produced by citrate reduction and exposed to the RF field either in solutions testing or after incubation with HepG2 cells. A rat hepatoma model using JM-1 cells and Fisher rats was employed using direct injection of nanoparticles into the tumor to focus the radiowaves for select heating. Temperatures were measured using a fiber-optic thermometer for real-time data. Solutions containing gold nanoparticles heated in a time- and power-dependent manner. HepG2 liver cancer cells cultured in the presence of gold nanoparticles achieved adequate heating to cause cell death upon exposure to the RF field with no cytotoxicity attributable to the gold nanoparticles themselves. In vivo rat exposures at 35 W using direct gold nanoparticle injections resulted in significant temperature increases and thermal injury at subcutaneous injection sites as compared to vehicle (water) injected controls. These data show that non invasive radiowave thermal ablation of cancer cells is feasible when facilitated by gold nanoparticles. Future studies will focus on tumor selective targeting of nanoparticles for in vivo tumor destruction.

  14. Effect of Gold Nanoparticle Conjugation on Peptide Dynamics and Structure

    Directory of Open Access Journals (Sweden)

    F. Marty Ytreberg

    2012-03-01

    Full Text Available Molecular dynamics simulations were used to characterize the structure and dynamics for several peptides and the effect of conjugating them to a gold nanoparticle. Peptide structure and dynamics were compared for two cases: unbound peptides in water, and peptides bound to the gold nanoparticle surface in water. The results show that conjugating the peptides to the gold nanoparticle usually decreases conformational entropy, but sometimes increases entropy. Conjugating the peptides can also result in more extended structures or more compact structures depending on the amino acid sequence of the peptide. The results also suggest that if one wishes to use peptide-nanoparticle conjugates for drug delivery it is important that the peptides contain secondary structure in solution because in our simulations the peptides with little to no secondary structure adsorbed to the nanoparticle surface.

  15. Presenting Precision Glycomacromolecules on Gold Nanoparticles for Increased Lectin Binding

    Directory of Open Access Journals (Sweden)

    Sophia Boden

    2017-12-01

    Full Text Available Glyco-functionalized gold nanoparticles have great potential as biosensors and as inhibitors due to their increased binding to carbohydrate-recognizing receptors such as the lectins. Here we apply previously developed solid phase polymer synthesis to obtain a series of precision glycomacromolecules that allows for straightforward variation of their chemical structure as well as functionalization of gold nanoparticles by ligand exchange. A novel building block is introduced allowing for the change of spacer building blocks within the macromolecular scaffold going from an ethylene glycol unit to an aliphatic spacer. Furthermore, the valency and overall length of the glycomacromolecule is varied. All glyco-functionalized gold nanoparticles show high degree of functionalization along with high stability in buffer solution. Therefore, a series of measurements applying UV-Vis spectroscopy, dynamic light scattering (DLS and surface plasmon resonance (SPR were performed studying the aggregation behavior of the glyco-functionalized gold nanoparticles in presence of model lectin Concanavalin A. While the multivalent presentation of glycomacromolecules on gold nanoparticles (AuNPs showed a strong increase in binding compared to the free ligands, we also observed an influence of the chemical structure of the ligand such as its valency or hydrophobicity on the resulting lectin interactions. The straightforward variation of the chemical structure of the precision glycomacromolecule thus gives access to tailor-made glyco-gold nanoparticles (glyco-AuNPs and fine-tuning of their lectin binding properties.

  16. Shape controlled growth of gold nanoparticles by a solution synthesis.

    Science.gov (United States)

    Chen, Ying; Gu, Xin; Nie, Cha-Geng; Jiang, Zhi-Yuan; Xie, Zhao-Xiong; Lin, Chang-Jian

    2005-09-07

    The shape of gold nanoparticles has been successfully tuned among penta-twinned decahedrons, truncated tetrahedrons, cubes, octahedrons, hexagonal thin plates by introducing a small amount of salt into a N,N-dimethylformamide (DMF) solution containing poly(vinyl pyrrolidone) (PVP), and changing the temperature or the concentration of the gold precursor.

  17. Controlling the morphology of multi-branched gold nanoparticles

    NARCIS (Netherlands)

    Ahmed, W.; Ahmed, Waqqar; Kooij, Ernst S.; van Silfhout, Arend; Poelsema, Bene

    2010-01-01

    We demonstrate a simple and versatile way to achieve high yield synthesis of shape- and size-controlled multi-branched gold nanoparticles (MBNPs). Control over the shape of the MBNPs was achieved by varying the ratio of gold to the mild reducing agent ascorbic acid, using a seed-mediated growth

  18. Toward efficient modification of large gold nanoparticles with DNA

    NARCIS (Netherlands)

    Gill, R.; Göeken, Kristian L; Subramaniam, V.

    2014-01-01

    DNA-coated gold nanoparticles are one of the most researched nano-bio hybrid systems. Traditionally their synthesis has been a long and tedious process, involving slow salt addition and long incubation steps. This stems from the fact that both DNA and gold particles are negatively charged, therefore

  19. Generation of polypeptide-templated gold nanoparticles using ionizing radiation.

    Science.gov (United States)

    Walker, Candace Rae; Pushpavanam, Karthik; Nair, Divya Geetha; Potta, Thrimoorthy; Sutiyoso, Caesario; Kodibagkar, Vikram D; Sapareto, Stephen; Chang, John; Rege, Kaushal

    2013-08-13

    Ionizing radiation, including γ rays and X-rays, are high-energy electromagnetic radiation with diverse applications in nuclear energy, astrophysics, and medicine. In this work, we describe the use of ionizing radiation and cysteine-containing elastin-like polypeptides (C(n)ELPs, where n = 2 or 12 cysteines in the polypeptide sequence) for the generation of gold nanoparticles. In the presence of C(n)ELPs, ionizing radiation doses higher than 175 Gy resulted in the formation of maroon-colored gold nanoparticle dispersions, with maximal absorbance at 520 nm, from colorless metal salts. Visible color changes were not observed in any of the control systems, indicating that ionizing radiation, gold salt solution, and C(n)ELPs were all required for nanoparticle formation. The hydrodynamic diameters of nanoparticles, determined using dynamic light scattering, were in the range of 80-150 nm, while TEM imaging indicated the formation of gold cores 10-20 nm in diameter. Interestingly, C2ELPs formed 1-2 nm diameter gold nanoparticles in the absence of radiation. Our results describe a facile method of nanoparticle formation in which nanoparticle size can be tailored based on radiation dose and C(n)ELP type. Further improvements in these polypeptide-based systems can lead to colorimetric detection of ionizing radiation in a variety of applications.

  20. A halogen-free synthesis of gold nanoparticles using gold(III) oxide

    Energy Technology Data Exchange (ETDEWEB)

    Sashuk, Volodymyr, E-mail: vsashuk@ichf.edu.pl; Rogaczewski, Konrad [Polish Academy of Sciences, Institute of Physical Chemistry (Poland)

    2016-09-15

    Gold nanoparticles are one of the most used nanomaterials. They are usually synthesized by the reduction of gold(III) chloride. However, the presence of halide ions in the reaction mixture is not always welcome. In some cases, these ions have detrimental influence on the morphology and structure of resulting nanoparticles. Here, we present a simple and halogen-free procedure to prepare gold nanoparticles by reduction of gold(III) oxide in neat oleylamine. The method provides the particles with an average size below 10 nm and dispersity of tens of percent. The process of nanoparticle formation was monitored using UV–Vis spectroscopy. The structure and chemical composition of the nanoparticles was determined by SEM, XPS and EDX. We also proposed the mechanism of reduction of gold(III) oxide based on MS, IR and NMR data. Importantly, the synthetic protocol is general and applicable for the preparation of other coinage metal nanoparticles from the corresponding metal oxides. For instance, we demonstrated that the absence of halogen enables efficient alloying of metals when preparing gold–silver bimetallic nanoparticles.

  1. A Novel Biological Synthesis of Gold Nanoparticle by ...

    African Journals Online (AJOL)

    scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR) for yield, particle size, shape and presence of different functional groups, respectively. The nanoparticles were centrifuged and re-dispersed in double distilled water thrice to purify them for FTIR studies. Results: The gold nanoparticles were ...

  2. Biosynthesis of silver and gold nanoparticles using Brevibacterium casei.

    Science.gov (United States)

    Kalishwaralal, Kalimuthu; Deepak, Venkataraman; Ram Kumar Pandian, SureshBabu; Kottaisamy, Muniasamy; BarathmaniKanth, Selvaraj; Kartikeyan, Bose; Gurunathan, Sangiliyandi

    2010-06-01

    The present study demonstrates an unprecedented green process for the production of spherical-shaped Au and Ag nanoparticles synthesized and stabilized using a bacterium, Brevibacterium casei. Aqueous solutions of chloroaurate ions for Au and Ag(+) ions for silver were treated with B. casei biomass for the formation of Au nanoparticles (AuNP) and Ag nanoparticles (AgNP). The nanometallic dispersions were characterized by surface plasmon absorbance measuring at 420 and 540 nm for Ag and Au nanoparticles, respectively. Transmission electron microscopy showed the formation of nanoparticles in the range of 10-50 nm (silver), and 10-50 nm (gold). XRD analysis of the silver and gold nanoparticles confirmed the formation of metallic silver and gold. Further analysis carried out by Fourier Transform Infrared Spectroscopy (FTIR), provides evidence for the presence of proteins as possible biomolecules responsible for the reduction and capping agent which helps in increasing the stability of the synthesized silver and gold nanoparticles. The biological activities of the synthesized particles were confirmed based on their stable anti-coagulant effects. The use of bacterium for nanoparticles synthesis offers the benefits of ecofriendliness and amenability for large-scale production. Copyright 2010 Elsevier B.V. All rights reserved.

  3. Spectroscopic evidence for the adsorption of propene on gold nanoparticles Spectroscopic evidence for the adsorption of propene on gold nanoparticles

    NARCIS (Netherlands)

    Nijhuis, T.A.; Sacaliuc, E.; Beale, A.M.; van der Eerden, A.M.J.; Schouten, J.C.; Weckhuysen, B.M.

    2008-01-01

    The adsorption of propene on supported gold nanoparticles has been experimentally identified as a reaction step in the hydro-epoxidation of propene. This new finding was made possible by applying a detailed analysis of in situ measured XANES spectra. For this purpose, gold-on-silica catalysts were

  4. Gold Nanoparticles with Stably Embedded Cu-64 and Their Use in Nanoparticle Research

    DEFF Research Database (Denmark)

    Jensen, A.I.; Frellsen, Anders Floor; Hansen, A. E.

    2016-01-01

    64Cu is a popular radionuclide for PET imaging and when 64Cu2+ is mixed with gold nanoparticles (AuNPs) it adheres to the gold surface. Taking advantage of this, we developed methods to trap the 64Cu within the AuNPs by embedding under additional layers of gold. This resulted in radiolabeling eff...

  5. Gold Nanoparticles Inhibit Matrix Metalloproteases without Cytotoxicity.

    Science.gov (United States)

    Hashimoto, M; Sasaki, J I; Yamaguchi, S; Kawai, K; Kawakami, H; Iwasaki, Y; Imazato, S

    2015-08-01

    Nanoparticles (NPs) are currently the focus of considerable attention for dental applications; however, their biological effects have not been fully elucidated. The long-term, slow release of matrix metalloproteases (MMPs) digests collagen fibrils within resin-dentin bonds. Therefore, MMP inhibitors can prolong the durability of resin-dentin bonds. However, there have been few reports evaluating the combined effect of MMP inhibition and the cytotoxic effects of NPs for dentin bonding. The aim of this study was to evaluate MMP inhibition and cytotoxic responses to gold (AuNPs) and platinum nanoparticles (PtNPs) stabilized by polyvinylpyrrolidone (PVP) in cultured murine macrophages (RAW264) by using MMP inhibition assays, measuring cell viability and inflammatory responses (quantitative reverse transcription polymerase chain reaction [RT-qPCR]), and conducting a micromorphological analysis by fluorescence and transmission electron microscopy. Cultured RAW264 cells were exposed to metal NPs at various concentrations (1, 10, 100, and 400 µg/mL). AuNPs and PtNPs markedly inhibited MMP-8 and MMP-9 activity. Although PtNPs were cytotoxic at high concentrations (100 and 400 µg/mL), no cytotoxic effects were observed for AuNPs at any concentration. Transmission electron microscopy images showed a significant nonrandom intercellular distribution for AuNPs and PtNPs, which were mostly observed to be localized in lysosomes but not in the nucleus. RT-qPCR analysis demonstrated inflammatory responses were not induced in RAW264 cells by AuNPs or PtNPs. The cytotoxicity of nanoparticles might depend on the core metal composition and arise from a "Trojan horse" effect; thus, MMP inhibition could be attributed to the surface charge of PVP, which forms the outer coating of NPs. The negative charge of the surface coating of PVP binds to Zn(2+) from the active center of MMPs by chelate binding and results in MMP inhibition. In summary, AuNPs are attractive NPs that effectively

  6. Thermo-Optical Properties of Colloids Enhanced by Gold Nanoparticles

    Science.gov (United States)

    Aleali, Hoda; Sarkhosh, Leila; Eslamifar, Mina; Karimzadeh, Rouhollah; Mansour, Nastaran

    2010-08-01

    This work presents a study on the thermo-optical properties of colloidal gold nanoparticles (AuNPs) under a low power laser irradiation at 532 nm. Samples of various gold volume fractions, ranging from 2.5×10-4 to 19.5×10-4%, are synthesized by nanosecond pulsed laser ablation of a pure gold plate in the distilled water. The formation of the AuNPs has been evidenced by optical absorption spectra and transmission electron microscopy. We investigate the effect of the gold nanoparticle concentration on thermo-optical properties of the colloids using the Z-scan technique. The nonlinear optical measurements exhibit a very large nonlinear refraction close to the surface plasmon resonance frequency of the nanoparticles. Our results reveal that the heat diffusion in the colloids is due to nonlocal thermal process. As the gold concentration increases, the temperature change within and around gold nanoparticles greatly enlarges the thermo-optic and thermal nonlinear refractive index coefficients of the samples. This work suggests that thermal nonlinear refraction will play an important role in development of photonic applications involving metal nanoparticles colloids.

  7. Amoxicillin functionalized gold nanoparticles reverts MRSA resistance.

    Science.gov (United States)

    Kalita, Sanjeeb; Kandimalla, Raghuram; Sharma, Kaustav Kalyan; Kataki, Amal Chandra; Deka, Manab; Kotoky, Jibon

    2016-04-01

    In this study, we have described the biosynthesis of biocompatible gold nanoparticles (GNPs) from aqueous extract of the aerial parts of a pteridophyte, "Adiantum philippense" by microwave irradiation and its surface functionalization with broad spectrum beta lactam antibiotic, amoxicillin (Amox). The functionalization of amoxicillin on GNPs (GNP-Amox) was carried out via electrostatic interaction of protonated amino group and thioether moiety mediated attractive forces. The synthesized GNPs and GNP-Amox were physicochemically characterized. UV-Vis spectroscopy, Zeta potential, XRD, FTIR and SERS (surface enhanced raman spectra) results confirmed the loading of Amox into GNPs. Loading of Amox to GNPs reduce amoxicillin cytotoxicity, whereas GNPs were found to be nontoxic to mouse fibroblast cell line (L929) as evident from MTT and acridine orange/ethidium bromide (AO/EtBr) live/dead cell assays. The GNP-Amox conjugates demonstrated enhanced broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. Furthermore, in-vitro and in-vivo assays of GNP-Amox revealed potent anti-MRSA activity and improved the survival rate. This indicates the subversion of antibiotic resistance mechanism by overcoming the effect of high levels of β-lactamase produced by methicillin resistant Staphylococcus aureus (MRSA). Taken together, this study demonstrates the positive attributes from GNP-Amox conjugates as a promising antibacterial therapeutic agent against MRSA as well as other pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Vibrational properties of gold nanoparticles obtained by green synthesis

    Science.gov (United States)

    Alvarez, Ramón A. B.; Cortez-Valadez, M.; Bueno, L. Oscar Neira; Britto Hurtado, R.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C. E.; Serrano-Corrales, Luis Ivan; Arizpe-Chávez, H.; Flores-Acosta, M.

    2016-10-01

    This study reports the synthesis and characterization of gold nanoparticles through an ecological method to obtain nanostructures from the extract of the plant Opuntia ficus-indica. Colloidal nanoparticles show sizes that vary between 10-20 nm, and present various geometric morphologies. The samples were characterized through optical absorption, Raman Spectroscopy and Transmission Electron Microscopy (TEM). Additionally, low energy metallic clusters of Aun (n=2-20 atoms) were modeled by computational quantum chemistry. The theoretical results were obtained with Density Functional Theory (DFT). The predicted results of Au clusters show a tendency and are correlated with the experimental results concerning the optical absorption bands and Raman spectroscopy in gold nanoparticles.

  9. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

    2014-01-01

    With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite-1 is reported and their high...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50% conversion of ethanol with 98...

  10. Formation and Aggregation of Gold (Electrum) Nanoparticles in Epithermal Ores

    OpenAIRE

    James A. Saunders; Michelle Burke

    2017-01-01

    Here, we review the concept that nanoparticles and colloids may have played a significant role in forming some types of hydrothermal ores deposits, particularly epithermal. This concept was first proposed almost a century ago but the development of new analytical technologies, lab experiments, and the discovery of new epithermal deposits where nanoparticles are evident have added credence to the “gold colloid theory”. Nanoparticles are defined to have at least one dimension <10−7 m, and ma...

  11. Reusable magnetic nanobiocatalyst for synthesis of silver and gold nanoparticles.

    Science.gov (United States)

    Mazumder, Jahirul Ahmed; Ahmad, Razi; Sardar, Meryam

    2016-12-01

    In the present work, we describe a simple procedure for the biosynthesis of nanosilver and gold by the reduction of silver nitrate and auric chloride respectively using a nanobiocatalyst. The nanobiocatalyst was prepared by covalent coupling of alpha amylase on (3-aminopropyl)triethoxysilane (APTES) modified iron oxide magnetic nanoparticles. The nanobiocatalyst retains 77% of its activity as compared to free alpha amylase. The nanobiocatalyst can be used up to three consecutive cycles for the synthesis of nano silver and gold. The biosynthesized nanoparticles after each cycle were characterized by UV-vis spectrophotometer, Dynamic Light Spectroscopy (DLS), Transmission Electron Microscope (TEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Silver and gold nanoparticles of same morphology and dimensions were formed in each cycle. The procedure for synthesis of nanoparticles using an immobilized enzyme is eco-friendly and can be used repeatedly. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Dynamic light scattering on bioconjugated laser generated gold nanoparticles.

    Directory of Open Access Journals (Sweden)

    Massimo Zimbone

    Full Text Available Gold nanoparticles (AuNPs conjugated to DNA are widely used for biomedical targeting and sensing applications. DNA functionalization is easily reached on laser generated gold nanoparticles because of their unique surface chemistry, not reproducible by other methods. In this context, we present an extensive investigation concerning the attachment of DNA to the surface of laser generated nanoparticles using Dynamic Light Scattering and UV-Vis spectroscopy. The DNA conjugation is highlighted by the increase of the hydrodynamic radius and by the UV-Vis spectra behavior. Our investigation indicates that Dynamic Light Scattering is a suitable analytical tool to evidence, directly and qualitatively, the binding between a DNA molecule and a gold nanoparticle, therefore it is ideal to monitor changes in the conjugation process when experimental conditions are varied.

  13. Microwave absorption properties of gold nanoparticle doped polymers

    DEFF Research Database (Denmark)

    Jiang, Chenhui; Ouattara, Lassana; Ingrosso, Chiara

    2011-01-01

    This paper presents a method for characterizing microwave absorption properties of gold nanoparticle doped polymers. The method is based on on-wafer measurements at the frequencies from 0.5GHz to 20GHz. The on-wafer measurement method makes it possible to characterize electromagnetic (EM) property...... of small volume samples. The epoxy based SU8 polymer and SU8 doped with gold nanoparticles are chosen as the samples under test. Two types of microwave test devices are designed for exciting the samples through electrical coupling and magnetic coupling, respectively. Measurement results demonstrate...... that the nanocomposites absorb a certain amount of microwave energy due to gold nanoparticles. Higher nanoparticle concentration results in more significant absorption effect....

  14. Comparison of amino acids interaction with gold nanoparticle.

    Science.gov (United States)

    Ramezani, Fatemeh; Amanlou, Massoud; Rafii-Tabar, Hashem

    2014-04-01

    The study of nanomaterial/biomolecule interface is an important emerging field in bionanoscience, and additionally in many biological processes such as hard-tissue growth and cell-surface adhesion. To have a deeper understanding of the amino acids/gold nanoparticle assemblies, the adsorption of these amino acids on the gold nanoparticles (GNPs) has been investigated via molecular dynamics simulation. In these simulations, all the constituent atoms of the nanoparticles were considered to be dynamic. The geometries of amino acids, when adsorbed on the nanoparticle, were studied and their flexibilities were compared with one another. The interaction of each of 20 amino acids was considered with 3 and 8 nm gold GNPs.

  15. Preparation of Radioactive Gold Nanoparticle by Neutron Activation

    OpenAIRE

    Rohadi Awaludin

    2010-01-01

    It was reported that gold nanoparticle could be used for cancer therapy using thermal effect. It is possible to kill cancer cells using radiation of radioisotope. Study on preparation of radioactive gold by neutron activation at central irradiation position (CIP) of G.A. Siwabessy reactor with neutron flux 1.26 x 1014 neutron s-1cm-2 has been carried out. It was revealed that a radioisotop of gold (198Au) was produced by neutron activation from natural gold. Calculation re...

  16. Synthesis of large uniform gold and core-shell gold-silver nanoparticles: Effect of temperature control

    Science.gov (United States)

    Tiunov, I. A.; Gorbachevskyy, M. V.; Kopitsyn, D. S.; Kotelev, M. S.; Ivanov, E. V.; Vinokurov, V. A.; Novikov, A. A.

    2016-01-01

    The temperatures of nucleation and growth for gold and silver nanoparticles are quite close to each other in citrate-based seeded-growth synthesis. Hence, thorough temperature control during the synthesis of gold and gold-silver core-shell nanoparticles is expected to improve the yield of uniform non-aggregated nanoparticles suitable for selective contrasting of surface defects. Gold and gold-silver core-shell nanoparticles of size ranging from 20 to 160 nm were synthesized using various means of temperature control. The synthesized nanoparticles were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and UV-Vis spectroscopy. Model nanocracks were milled on pipeline steel specimen by focused ion beam (FIB). It was found that to produce large uniform core-shell nanoparticles, thorough temperature control is required during formation of the gold seeds and the silver shell. Moreover, the synthesized nanoparticles were used for selective contrasting of defects on metal surface.

  17. Biosynthesis of Gold Nanoparticles (Green-gold Using Leaf Extract of Terminalia Catappa

    Directory of Open Access Journals (Sweden)

    Balaprasad Ankamwar

    2010-01-01

    Full Text Available The synthesis of eco-friendly nanoparticles is evergreen branch of nanoscience for biomedical application. Low cost of synthesis and non toxicity are main features make it more attractive potential option for biomedical field and elsewhere. Here, we report the synthesis of gold nanoparticles in aqueous medium using Terminalia catappa (Almond leaf extract as the reducing and stabilizing agent. On treating chloroauric acid solutions with Terminalia catappa (TC leaf extract rapid reduction of chloroaurate ions is observed leading to the formation of highly stable gold nanoparticles in solution. TEM analysis of the gold nanoparticles indicated that they ranged in size from 10 to 35 nm with average size of 21.9 nm.

  18. Delivery of a hydrophobic phthalocyanine photosensitizer using PEGylated gold nanoparticle conjugates for the in vivo photodynamic therapy of amelanotic melanoma.

    Science.gov (United States)

    Camerin, Monica; Moreno, Miguel; Marín, María J; Schofield, Claire L; Chambrier, Isabelle; Cook, Michael J; Coppellotti, Olimpia; Jori, Giulio; Russell, David A

    2016-05-11

    Photodynamic therapy (PDT) is a treatment of cancer whereby tumours are destroyed by reactive oxygen species generated upon photoactivation of a photosensitizer drug. Hydrophobic photosensitizers are known to be ideal for PDT; however, their hydrophobicity necessitates that they are typically administered using emulsions. Here, a delivery vehicle for photodynamic therapy based on the co-self-assembly of both a Zn(ii)-phthalocyanine derivative photosensitizer and a polyethylene glycol (PEG) derivative onto gold nanoparticles is reported. The PEG on the particle surface ensured that the conjugates were water soluble and enhanced their retention in the serum, improving the efficiency of PDT in vivo. The pharmacokinetic behaviour of the nanoparticle conjugates following intravenous injection into C57/BL6 mice bearing a subcutaneous transplanted B78H1 amelanotic melanoma showed a significant increase of retention of the nanoparticles in the tumour. PDT tumour destruction was achieved 3 h following injection of the nanoparticle conjugates leading to a remarkable 40% of the treated mice showing no tumour regrowth and complete survival. These results highlight that dual functionalised nanoparticles exhibit significant potential in PDT of cancer especially for difficult to treat cancers such as amelanotic melanoma.

  19. Fluorescence-Guided Probes of Aptamer-Targeted Gold Nanoparticles with Computed Tomography Imaging Accesses for in Vivo Tumor Resection

    Science.gov (United States)

    Li, Cheng-Hung; Kuo, Tsung-Rong; Su, Hsin-Jan; Lai, Wei-Yun; Yang, Pan-Chyr; Chen, Jinn-Shiun; Wang, Di-Yan; Wu, Yi-Chun; Chen, Chia-Chun

    2015-01-01

    Recent development of molecular imaging probes for fluorescence-guided surgery has shown great progresses for determining tumor margin to execute the tissue resection. Here we synthesize the fluorescent gold nanoparticles conjugated with diatrizoic acid and nucleolin-targeted AS1411 aptamer. The nanoparticle conjugates exhibit high water-solubility, good biocompatibility, visible fluorescence and strong X-ray attenuation for computed tomography (CT) contrast enhancement. The fluorescent nanoparticle conjugates are applied as a molecular contrast agent to reveal the tumor location in CL1-5 tumor-bearing mice by CT imaging. Furthermore, the orange-red fluorescence emitting from the conjugates in the CL1-5 tumor can be easily visualized by the naked eyes. After the resection, the IVIS measurements show that the fluorescence signal of the nanoparticle conjugates in the tumor is greatly enhanced in comparison to that in the controlled experiment. Our work has shown potential application of functionalized nanoparticles as a dual-function imaging agent in clinical fluorescence-guided surgery. PMID:26507179

  20. Synthesis and Luminescence Properties of Water Soluble α-NaGdF4/β-NaYF4:Yb,Er Core-Shell Nanoparticles

    Science.gov (United States)

    Chen, Huan; Zhang, Peipei; Cui, Haining; Qin, Weiping; Zhao, Dan

    2017-09-01

    Hexagonal phase (β) sodium rare earth tetrafluorides (NaREF4, RE = Y, Gd, Lu, et al.) are considered the ideal matrices for lanthanide (Ln) ions doped upconversion (UC) luminescence materials, because they can provide favorable crystal lattice structures for the doped luminescent Ln ions to make intensive emissions. However, the cubic phase (α) NaREF4 always preferentially forms at low reaction temperature in short time as it is dynamically stable. Therefore, it is hard to obtain small sized β-NaREF4 via the traditional solvothermal method. In this paper, small sized β-NaYF4:Yb,Er nanoparticles were synthesized by a heterogeneous-core-induced method via the solvothermal reaction. The heterogeneous α-NaGdF4/β-NaYF4: Yb, Er core-shell structure was confirmed by the local elemental mapping. The formation mechanism of β-NaYF4:Yb,Er shell on the surface of α-NaGdF4 core was explained in detail. We reasoned that a hetero interface with a lower lattice symmetric structure was produced by cation exchanges between the core and shell, which caused the preferential growth of anisotropic hexagonal phase shell. The existence of this hetero interface has also been proven by observation of Gd3+ UC emission.

  1. Smart Self-Assembled Nanosystem Based on Water-Soluble Pillararene and Rare-Earth-Doped Upconversion Nanoparticles for pH-Responsive Drug Delivery.

    Science.gov (United States)

    Li, Haihong; Wei, Ruoyan; Yan, Gui-Hua; Sun, Ji; Li, Chunju; Wang, Haifang; Shi, Liyi; Capobianco, John A; Sun, Lining

    2018-01-24

    Exploring novel drug delivery systems with good stability and new structure to integrate pillararene and upconversion nanoparticles (UCNPs) into one system continues to be an important challenge. Herein, we report a novel preparation of a supramolecular upconversion nanosystem via the host-guest complexation based on carboxylate-based pillar[5]arene (WP5) and 15-carboxy-N,N,N-trialkylpentadecan-1-ammonium bromide (1)-functionalized UCNPs to produce WP5⊃1-UCNPs that can be loaded with the chemotherapeutic drug doxorubicin (DOX). Importantly, the WP5 on the surface of the drug-loaded nanosystem can be efficiently protonated under acidic conditions, resulting in the collapse of the nanosystem and drug release. Moreover, cellular uptake confirms that the nanosystem can enter human cervical cancer (HeLa) cells, resulting in drug accumulation in the cells. More importantly, cytotoxicity experiments demonstrated the excellent biocompatibility of WP5⊃1-UCNPs without loading DOX and that the nanosystem DOX-WP5⊃1-UCNPs exhibited an ability of killing HeLa cells effectively. We also investigated magnetic resonance imaging and upconversion luminescence imaging, which may be employed as visual imaging agents in cancer diagnosis and treatment. Thus, in the present work, we show a simple yet powerful strategy to combine UCNPs and pillar[5]arene to produce a unified nanosystem for dual-mode bioimaging-guided therapeutic applications.

  2. Synthesis and characterization of pHLIP® coated gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Jennifer L. Daniels

    2017-07-01

    Full Text Available Novel approaches in synthesis of spherical and multispiked gold nanoparticles coated with polyethylene glycol (PEG and pH Low Insertion Peptide (pHLIP® were introduced. The presence of a tumor-targeting pHLIP® peptide in the nanoparticle coating enhances the stability of particles in solution and promotes a pH-dependent cellular uptake. The spherical particles were prepared with sodium citrate as a gold reducing agent to form particles of 7.0±2.5 nm in mean metallic core diameter and ∼43 nm in mean hydrodynamic diameter. The particles that were injected into tumors in mice (21 µg of gold were homogeneously distributed within a tumor mass with no staining of the muscle tissue adjacent to the tumor. Up to 30% of the injected gold dose remained within the tumor one hour post-injection. The multispiked gold nanoparticles with a mean metallic core diameter of 146.0±50.4 nm and a mean hydrodynamic size of ~161 nm were prepared using ascorbic acid as a reducing agent and disk-like bicelles as a template. Only the presence of a soft template, like bicelles, ensured the appearance of spiked nanoparticles with resonance in the near infrared region. The irradiation of spiked gold nanoparticles by an 805 nm laser led to the time- and concentration-dependent increase of temperature. Both pHLIP® and PEG coated gold spherical and multispiked nanoparticles might find application in radiation and thermal therapies of tumors.

  3. One-step synthesis of small-sized and water-soluble NaREF4 upconversion nanoparticles for in vitro cell imaging and drug delivery.

    Science.gov (United States)

    Yang, Dongmei; Dai, Yunlu; Ma, Pingan; Kang, Xiaojiao; Cheng, Ziyong; Li, Chunxia; Lin, Jun

    2013-02-18

    Small (2-28 nm) NaREF(4) (rare earth (RE)=Nd-Lu, Y) nanoparticles (NPs) were prepared by an oil/water two-phase approach. Meanwhile, hydrophilic NPs can be obtained through a successful phase-transition process by introducing the amphiphilic surfactant sodium dodecylsulfate (SDS) into the same reaction system. Hollow-structured NaREF(4) (RE=Y, Yb, Lu) NPs can be fabricated in situ by electron-beam lithography on solid NPs. The MTT assay indicates that these hydrophilic NPs with hollow structures exhibit good biocompatibility. The as-prepared hollow-structured NPs can be used as anti-cancer drug carriers for drug storage/release investigations. Doxorubicin hydrochloride (DOX) was taken as model drug. The release of DOX from hollow α-NaLuF(4):20% Yb(3+), 2% Er(3+) exhibits a pH-sensitive release patterns. Confocal microscopy observations indicate that the NPs can be taken up by HeLa cells and show obvious anti-cancer efficacy. Furthermore, α-NaLuF(4):20% Yb(3+), 2% Er(3+) NPs show bright-red emission under IR excitation, making both the excitation and emission light fall within the "optical window" of biological tissues. The application of α-NaLuF(4):20% Yb(3+), 2% Er(3+) in the luminescence imaging of cells was also investigated, which shows a bright-red emission without background noise. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Ecofriendly gold nanoparticles - Lysozyme interaction: Thermodynamical perspectives.

    Science.gov (United States)

    Roy, Swarup; Saxena, Shailendra K; Mishra, Suryakant; Yogi, Priyanka; Sagdeo, P R; Kumar, Rajesh

    2017-09-01

    In the featured work interaction between biosynthesized gold nanoparticles (GNP) and lysozyme (Lys) has been studied using multi-spectroscopic approach. A moderate association constant (Kapp) of 2.66×104L/mol has been observed indicative of interactive nature. The binding constant (Kb) was 1.99, 6.30 and 31.6×104L/mol at 291, 298 and 305K respectively and the number of binding sites (n) was found to be approximately one. Estimated values of thermodynamic parameters (Enthalpy change, ΔH=141.99kJ/mol, entropy change, ΔS=570J/mol/K, Gibbs free energy change, ΔG=-27.86kJ/mol at 298K) suggest hydrophobic force as the main responsible factor for the Lys-GNP interaction and also the process of interaction is spontaneous. The average binding distance (r=3.06nm) and the critical energy transfer distance (Ro=1.84nm) between GNP and Lys was also evaluated using Förster's non-radiative energy transfer (FRET) theory and results clearly indicate that non-radiative type energy transfer is possible. Moreover, the addition of GNP does not show any significant change in the secondary structure of Lys as confirmed from circular dichroism (CD) spectra. Furthermore, NMR spectroscopy also indicates interaction between Lys and GNP. The resulting insight is important for the better understanding of structural nature and thermodynamic aspects of binding between the Lys and GNP. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Microbial mediated preparation, characterization and optimization of gold nanoparticles

    Science.gov (United States)

    Barabadi, Hamed; Honary, Soheila; Ebrahimi, Pouneh; Mohammadi, Milad Ali; Alizadeh, Ahad; Naghibi, Farzaneh

    2014-01-01

    The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 °C and 200 rpm for ten days and then the supernatant was separated from the mycelia to convert AuCl4 solution into gold nanoparticles. The synthesized nanoparticles in the optimum conditions were formed with fairly well-defined dimensions and good monodispersity. The characterizations were done by using different methods (UV-Visible Spectroscopy, Fluorescence, FT-IR, AFM (Atomic Force Microscopy) and DLS (Dynamic Light Scattering). The bioconversion was optimized by Box-Behnken experimental design. The results show that the effective factors in this process were concentration of AuCl4, pH of medium and temperature of shaker incubator. The R2 value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations. PMID:25763059

  6. Coassembly of gold nanoparticles and cellulose nanocrystals in composite films.

    Science.gov (United States)

    Lukach, Ariella; Thérien-Aubin, Héloïse; Querejeta-Fernández, Ana; Pitch, Natalie; Chauve, Grégory; Méthot, Myriam; Bouchard, Jean; Kumacheva, Eugenia

    2015-05-12

    Coassembly of nanoparticles with different size-, shape-, and composition-dependent properties is a promising approach to the design and fabrication of functional materials and devices. This paper reports the results of a detailed investigation of the formation and properties of free-stranding composite films formed by the coassembly of cellulose nanocrystals and shape-isotropic plasmonic gold nanoparticles. The effect of gold nanoparticle size, surface charge, and concentration on the structural and optical properties of the composite films has been studied. The composite films retained photonic crystal and chiroptical activity properties. The size and surface charge of gold nanoparticles had a minor effect on the structure and properties of the composite films, while the concentration of gold nanoparticles in the composite material played a more significant role and can be used to fine-tune the optical properties of materials derived from cellulose nanocrystals. These findings significantly broaden the range of nanoparticles that can be used for producing nanocomposite materials based on cellulose nanocrystals. The simplicity of film preparation, the abundance of cellulose nanocrystals, and the robust, free-standing nature of the composite films offer highly advantageous features and pave the way for the generation of functional materials with coupled optical properties.

  7. Microbial mediated preparation, characterization and optimization of gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Hamed Barabadi

    2014-12-01

    Full Text Available The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 ºC and 200 rpm for ten days and then the supernatant was separated from the mycelia to convert AuCl4 solution into gold nanoparticles. The synthesized nanoparticles in the optimum conditions were formed with fairly well-defined dimensions and good monodispersity. The characterizations were done by using different methods (UV-Visible Spectroscopy, Fluorescence, FT-IR, AFM (Atomic Force Microscopy and DLS (Dynamic Light Scattering. The bioconversion was optimized by Box-Behnken experimental design. The results show that the effective factors in this process were concentration of AuCl4, pH of medium and temperature of shaker incubator. The R² value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations.

  8. Microbial mediated preparation, characterization and optimization of gold nanoparticles.

    Science.gov (United States)

    Barabadi, Hamed; Honary, Soheila; Ebrahimi, Pouneh; Mohammadi, Milad Ali; Alizadeh, Ahad; Naghibi, Farzaneh

    2014-01-01

    The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 °C and 200 rpm for ten days and then the supernatant was separated from the mycelia to convert AuCl₄ solution into gold nanoparticles. The synthesized nanoparticles in the optimum conditions were formed with fairly well-defined dimensions and good monodispersity. The characterizations were done by using different methods (UV-Visible Spectroscopy, Fluorescence, FT-IR, AFM (Atomic Force Microscopy) and DLS (Dynamic Light Scattering). The bioconversion was optimized by Box-Behnken experimental design. The results show that the effective factors in this process were concentration of AuCl₄, pH of medium and temperature of shaker incubator. The R(2) value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations.

  9. Gold nanoparticles evaluation using functional optical coherence tomography

    Science.gov (United States)

    StrÄ kowski, Marcin R.; Głowacki, Maciej; Kamińska, Aleksandra; Sawczak, Mirosław

    2017-02-01

    The main object of this research was to assess the ability to characterize the gold nanoparticles using optical modalities like optical coherence tomography. Since the nanoparticles, especially gold one, have been very attractive for medical diagnosis and treatment the amount of research activities have been growing rapidly. The nanoparticles designed for different applications like contrast agents or drugs delivery change the optical features of tissue in different way. Therefore, the expanded analysis of scattering optical signal may lead to obtain much more useful information about the tissues health and the treatment efficiency. The noninvasive measurements of the concentration and distribution of the nanoparticles, as well as their size in the media have been taken under consideration. For this purpose the polarization sensitive optical coherence tomography system with spectroscopic analysis (PS-SOCT) has been designed and used. In this contribution we are going to present the PS-SOCT measurement data obtained for the gold nanoparticles. The measurements have been taken for the liquid (gold nanoparticles in water) samples changing the particles concentrations in time.

  10. DnaK protein alleviates toxicity induced by citrate-coated gold nanoparticles in Escherichia coli

    National Research Council Canada - National Science Library

    Makumire, Stanley; Revaprasadu, Neerish; Shonhai, Addmore

    2015-01-01

    ... (called DnaK in prokaryotes) is one of the most prominent molecular chaperones. Since gold nanoparticles exhibit chaperone-like function in vitro, we investigated the effect of citrate-coated gold nanoparticles on the growth of E...

  11. Xanthan gum stabilized gold nanoparticles: characterization, biocompatibility, stability and cytotoxicity.

    Science.gov (United States)

    Pooja, Deep; Panyaram, Sravani; Kulhari, Hitesh; Rachamalla, Shyam S; Sistla, Ramakrishna

    2014-09-22

    Xanthan gum (XG) has been widely used in food, pharmaceutical and cosmetic industries. In the present study, we explored the potential of XG in the synthesis of gold nanoparticle. XG was used as both reducing and stabilizing agent. The effect of various formulation and process variables such as temperature, reaction time, gum concentration, gum volume and gold concentration, in GNP preparation was determined. The XG stabilized, rubey-red XGNP were obtained with 5 ml of XG aqueous solution (1.5 mg/ml). The optimum temperature was 80°C whereas the reaction time was 3 h. The optimized nanoparticles were also investigated as drug delivery carrier for doxorubicin hydrochloride. DOX loaded gold nanoparticles (DXGP) were characterized by dynamic light scattering, TEM, FTIR, and DSC analysis. The synthesized nanoparticle showed mean particle size of 15-20 nm and zeta potential -29.1 mV. The colloidal stability of DXGP was studied under different conditions of pH, electrolytes and serum. Nanoparticles were found to be stable at pH range between pH 5-9 and NaCl concentration up to 0.5 M. In serum, nanoparticles showed significant stability up to 24h. During toxicity studies, nanoparticles were found biocompatible and non-toxic. Compared with free DOX, DXGP displayed 3 times more cytotoxicity in A549 cells. In conclusion, this study provided an insight to synthesize GNP without using harsh chemicals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Gold nanoparticles for tumour detection and treatment

    NARCIS (Netherlands)

    Hartsuiker, Liesbeth; Petersen, W.; Petersen, Wilhelmina; Jose, J.; Jose, J.; van Es, P.; van Es, Peter; Lenferink, Aufrid T.M.; Poot, Andreas A.; Terstappen, Leonardus Wendelinus Mathias Marie; van Leeuwen, Ton; Manohar, Srirang; Otto, Cornelis

    2011-01-01

    The use of nanoparticles in biomedical applications is emerging rapidly. Recent developments have led to numerous studies of noble metal nanoparticles, down to the level of single molecule detection in living cells. The application of noble metal nanoparticles in diagnostics and treatment of early

  13. Gold nanoparticle-based microfluidic sensor for mercury detection

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Jensen, Thomas Glasdam; Kutter, Jörg Peter

    2011-01-01

    The contamination of natural resources by human activity can have severe socio-economical impacts. Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for remote/field sensing. A gold nanoparticle-based lab-on-a-chip ......-on-a-chip device was developed for the rapid, in-field detection and quantification of mercury in aquatic environments. Rhodamine 6G functionalized gold nanoparticles allowed the on-chip fluorescence detection of mercury in aqueous samples with a limit of detection of 7 nM....

  14. Gold nanoparticles in breast cancer treatment: Promise and potential pitfalls

    Science.gov (United States)

    Lee, Jihyoun; Chatterjee, Dev Kumar; Lee, Min Hyuk; Krishnan, Sunil

    2014-01-01

    Despite remarkable achievements in the treatment of breast cancer, some obstacles still remain. Gold nanoparticles may prove valuable in addressing these problems owing to their unique characteristics, including their enhanced permeability and retention in tumor tissue, their light absorbance and surface plasmon resonance in near-infrared light, their interaction with radiation to generate secondary electrons, and their ability to be conjugated with drugs or other agents. Herein, we discuss some basic concepts of gold nanoparticles, and early results from studies regarding their use in breast cancer, including toxicity and side effects. We also discuss these particles’ potential clinical applications. PMID:24556077

  15. Gold nanoparticles on polarizable surfaces as Raman scattering antennas.

    Science.gov (United States)

    Chen, Shiuan-Yeh; Mock, Jack J; Hill, Ryan T; Chilkoti, Ashutosh; Smith, David R; Lazarides, Anne A

    2010-11-23

    Surface plasmons supported by metal nanoparticles are perturbed by coupling to a surface that is polarizable. Coupling results in enhancement of near fields and may increase the scattering efficiency of radiative modes. In this study, we investigate the Rayleigh and Raman scattering properties of gold nanoparticles functionalized with cyanine deposited on silicon and quartz wafers and on gold thin films. Dark-field scattering images display red shifting of the gold nanoparticle plasmon resonance and doughnut-shaped scattering patterns when particles are deposited on silicon or on a gold film. The imaged radiation patterns and individual particle spectra reveal that the polarizable substrates control both the orientation and brightness of the radiative modes. Comparison with simulation indicates that, in a particle-surface system with a fixed junction width, plasmon band shifts are controlled quantitatively by the permittivity of the wafer or the film. Surface-enhanced resonance Raman scattering (SERRS) spectra and images are collected from cyanine on particles on gold films. SERRS images of the particles on gold films are doughnut-shaped as are their Rayleigh images, indicating that the SERRS is controlled by the polarization of plasmons in the antenna nanostructures. Near-field enhancement and radiative efficiency of the antenna are sufficient to enable Raman scattering cyanines to function as gap field probes. Through collective interpretation of individual particle Rayleigh spectra and spectral simulations, the geometric basis for small observed variations in the wavelength and intensity of plasmon resonant scattering from individual antenna on the three surfaces is explained.

  16. Bio-mediated synthesis, characterization and cytotoxicity of gold nanoparticles.

    Science.gov (United States)

    Klekotko, Magdalena; Matczyszyn, Katarzyna; Siednienko, Jakub; Olesiak-Banska, Joanna; Pawlik, Krzysztof; Samoc, Marek

    2015-11-21

    We report here a "green" approach for the synthesis of gold nanoparticles (GNPs) in which the Mentha piperita extract was applied for the bioreduction of chloroauric acid and the stabilization of the formed nanostructures. The obtained GNPs were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). The reduction of gold ions with the plant extract leads to the production of nanoparticles with various shapes (spherical, triangular and hexagonal) and sizes (from 10 to 300 nm). The kinetics of the reaction was monitored and various conditions of the synthesis were investigated. As a result, we established protocols optimized towards the synthesis of nanospheres and nanoprisms of gold. The cytotoxic effect of the obtained gold nanoparticles was studied by performing MTT assay, which showed lower cytotoxicity of the biosynthesized GNPs compared to gold nanorods synthesized using the usual seed-mediated growth. The results suggest that the synthesis using plant extracts may be a useful method to produce gold nanostructures for various biological and medical applications.

  17. Photoinduced energy and charge transfer in layered porphyrin-gold nanoparticle thin films

    NARCIS (Netherlands)

    Kotiaho, Anne; Lahtinen, Riikka; Lehtivuori, Heli; Tkachenko, Nikolai V.; Lemmetyinen, Helge

    2008-01-01

    In thin films of porphyrin (H2P) and gold nanoparticles (AuNPs), photoexcitation of porphyrins leads to energy and charge transfer to the gold nanoparticles. Alternating layers of porphyrins and octanethiol protected gold nanoparticles (dcore ∼3 nm) were deposited on solid substrates via the

  18. Preparation of 2 nm gold nanoparticles for in vitro and in vivo applications

    OpenAIRE

    Moyano, Daniel F.; Duncan, Bradley; Rotello, Vincent M.

    2013-01-01

    Gold nanoparticles have been a versatile tool in recent years for the exploration of biological systems. However, challenges with purification and adequate surface coverage limit the biocompatibility of gold nanoparticles. Here, we describe a detailed procedure for the synthesis, purification, and functionalization of biologically compatible gold nanoparticles for in vitro and in vivo studies.

  19. GOLD NANOPARTICLES ENCAPSULATED IN A POLYMERIC MATRIX OF SODIUM ALGINATE

    Directory of Open Access Journals (Sweden)

    Oana Lelia POP

    2016-11-01

    Full Text Available Plasmonic nanoparticles can be used as building blocks for the design of multifunctional systems based on polymeric capsules. The use of functionalised particles in therapeutics and imaging and understanding their effect on the cell functions are among the current challenges in nanobiotechnology and nanomedicine. The aim of the study was to manufacture and characterize polymeric microstructures by encapsulating plasmonic gold nanoparticles in biocompatible matrix of sodium alginate. The gold nanoparticles were obtained by reduction of tetracluoroauric acid with sodium citrate. To characterize the microcapsules, UV-Vis and FTIR spectroscopy, optical and confocal microscopy experiments were performed. In vitro cytotoxicity tests on HFL-1 cells were also performed. The capsules have spherical shape and 120 μm diameter. The presence of encapsulated gold nanoparticles is also shown by confocal microscopy. In vitro tests show that the microcapsules are not cytotoxic upon 24 h of cells exposure to microcapsules concentrations ranging from 2.5 to 25 capsules per cell. The obtained microcapsules of sodium alginate loaded with plasmonic gold nanoparticles could potentially be considered as release systems for biologically relevant molecules.

  20. Recent progress in theranostic applications of hybrid gold nanoparticles.

    Science.gov (United States)

    Gharatape, Alireza; Salehi, Roya

    2017-09-29

    A significant area of research is theranostic applications of nanoparticles, which involves efforts to improve delivery and reduce side effects. Accordingly, the introduction of a safe, effective, and, most importantly, renewable strategy to target, deliver and image disease cells is important. This state-of-the-art review focuses on studies done from 2013 to 2016 regarding the development of hybrid gold nanoparticles as theranostic agents in the diagnosis and treatment of cancer and infectious disease. Several syntheses (chemical and green) methods of gold nanoparticles and their applications in imaging, targeting, and delivery are reviewed; their photothermal efficiency is discussed as is the toxicity of gold nanoparticles. Owing to the unique characterizations of hybrid gold nanoparticles and their potential to be developed as multifunctional, we predict they will present an undeniable role in clinical studies and provide treatment platforms for various diseases. Thus, their clearance and interactions with extra- and intra-cellular molecules need to be considered in future projects. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. Carbon nanotubes/laser ablation gold nanoparticles composites

    Energy Technology Data Exchange (ETDEWEB)

    Lascialfari, Luisa [Department of Chemistry, Università di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, Firenze 50019 (Italy); Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, Sesto Fiorentino, Firenze 50019 (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Via Giusti 9, Firenze 50123 (Italy); Marsili, Paolo [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, Sesto Fiorentino, Firenze 50019 (Italy); Caporali, Stefano [Department of Chemistry, Università di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, Firenze 50019 (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Via Giusti 9, Firenze 50123 (Italy); Muniz-Miranda, Maurizio [Department of Chemistry, Università di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, Firenze 50019 (Italy); Margheri, Giancarlo [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, Sesto Fiorentino, Firenze 50019 (Italy); Serafini, Andrea; Brandi, Alberto [Department of Chemistry, Università di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, Firenze 50019 (Italy); Giorgetti, Emilia, E-mail: emilia.giorgetti@fi.isc.cnr.it [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, Sesto Fiorentino, Firenze 50019 (Italy); Cicchi, Stefano, E-mail: stefano.cicchi@unifi.it [Department of Chemistry, Università di Firenze, Via della Lastruccia 3-13, Sesto Fiorentino, Firenze 50019 (Italy); Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Via Giusti 9, Firenze 50123 (Italy)

    2014-10-31

    The production of nanohybrids formed by oxidized multiwalled carbon nanotubes (MWCNTs) and nanoparticles, produced by pulsed laser ablation in liquids process, is described. The use of linkers, obtained by transformation of pyrene-1-butanol, is mandatory to generate an efficient and stable interaction between the two components. Transmission electron microscopy and X-ray photoelectron spectroscopy analysis showed the obtainment of the efficient coverage of the MWCNTs by nanoparticles composed by metal gold and, partially, by oxides. - Highlights: • Laser ablation is a used for the production of gold nanoparticle colloids • An efficient decoration of carbon nanotubes with nanoparticles is obtained through the use of a linker • This method allows an efficient and tunable preparation of carbon nanotube hybrids.

  2. Electron beam/γ-ray irradiation synthesis of gold nanoparticles and investigation of antioxidant activity

    Science.gov (United States)

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

    2014-12-01

    Colloidal solutions of 1 mM gold nanoparticles (AuNPs) were synthesized by γ-ray Co-60 and electron beam irradiation using 1% water soluble chitosan (WSC) with different molecular weight (Mw) as stabilizer. The AuNPs size measured from TEM images was of 7.1 and 15.1 nm for electron beam and γ-ray Co-60, respectively. The AuNPs sizes of 9.8, 15.1 and 22.4 nm stabilized by different WSC Mw of 155 × 103, 78 × 103 and 29 × 103 g mol-1, respectively, were also synthesized by γ-ray Co-60 irradiation. Antioxidant activity of AuNPs with different size from 7.1 to 20.0 nm was investigated using free radical 2,2‧-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+). Results indicated that the smaller size of AuNPs exhibited higher antioxidant activity. In particular, the antioxidant efficiency was of nearly 100, 75, 65, 52 and 30% for 7.1, 9.8, 15.1, 20.0 nm AuNPs and WSC 0.1%, respectively, at the same reaction time of 270 min. Thus, due to the compatibility of WSC and the unique property of AuNPs, the pure colloidal AuNPs/WSC solutions synthesized by irradiation method can be potentially applied in biomedicine, cosmetics and in other fields as well.

  3. "Click" chemistry mildly stabilizes bifunctional gold nanoparticles for sensing and catalysis.

    Science.gov (United States)

    Li, Na; Zhao, Pengxiang; Liu, Na; Echeverria, María; Moya, Sergio; Salmon, Lionel; Ruiz, Jaime; Astruc, Didier

    2014-07-01

    A large family of bifunctional 1,2,3-triazole derivatives that contain both a polyethylene glycol (PEG) chain and another functional fragment (e.g., a polymer, dendron, alcohol, carboxylic acid, allyl, fluorescence dye, redox-robust metal complex, or a β-cyclodextrin unit) has been synthesized by facile "click" chemistry and mildly coordinated to nanogold particles, thus providing stable water-soluble gold nanoparticles (AuNPs) in the size range 3.0-11.2 nm with various properties and applications. In particular, the sensing properties of these AuNPs are illustrated through the detection of an analogue of a warfare agent (i.e., sulfur mustard) by means of a fluorescence "turn-on" assay, and the catalytic activity of the smallest triazole-AuNPs (core of 3.0 nm) is excellent for the reduction of 4-nitrophenol in water. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Encapsulation of Gold Nanoparticles in a DNA Origami Cage

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Jacovetty, Erica L.; Liu, Yan; Yan, Hao

    2011-01-21

    A critical challenge in nanoparticle (NP) surface functionalization is to label the NP surface with a single copy of a functional group or to display multiple, unique molecules on the NP surface with control of the orientation and intermolecular distance. This challenge was addressed with the construction of a spatially addressable, self-assembling DNA origami nanocage that encapsulates gold nanoparticles and interrupts its surface symmetry

  5. Microbial mediated preparation, characterization and optimization of gold nanoparticles

    OpenAIRE

    Barabadi, Hamed; Honary, Soheila; Ebrahimi, Pouneh; Mohammadi, Milad Ali; Alizadeh, Ahad; Naghibi, Farzaneh

    2014-01-01

    The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 ºC and 200 rpm for ten days and then the supernatant ...

  6. Microbial mediated preparation, characterization and optimization of gold nanoparticles

    OpenAIRE

    Hamed Barabadi; Soheila Honary; Pouneh Ebrahimi; Milad Ali Mohammadi; Ahad Alizadeh; Farzaneh Naghibi

    2014-01-01

    The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 ºC and 200 rpm for ten days and then the superna...

  7. Peptide-functionalized iron oxide magnetic nanoparticle for gold mining

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Wei-Zheng; Cetinel, Sibel; Sharma, Kumakshi; Borujeny, Elham Rafie; Montemagno, Carlo, E-mail: montemag@ualberta.ca [Ingenuity Lab, 1-070C (Canada)

    2017-02-15

    Here, we present our work on preparing a novel nanomaterial composed of inorganic binding peptides and magnetic nanoparticles for inorganic mining. Two previously selected and well-characterized gold-binding peptides from cell surface display, AuBP1 and AuBP2, were exploited. This nanomaterial (AuBP-MNP) was designed to fulfill the following two significant functions: the surface conjugated gold-binding peptide will recognize and selectively bind to gold, while the magnetic nano-sized core will respond and migrate according to the applied external magnetic field. This will allow the smart nanomaterial to mine an individual material (gold) from a pool of mixture, without excessive solvent extraction, filtration, and concentration steps. The working efficiency of AuBP-MNP was determined by showing a dramatic reduction of gold nanoparticle colloid concentration, monitored by spectroscopy. The binding kinetics of AuBP-MNP onto the gold surface was determined using surface plasmon resonance (SPR) spectroscopy, which exhibits around 100 times higher binding kinetics than peptides alone. The binding capacity of AuBP-MNP was demonstrated by a bench-top mining test with gold microparticles.

  8. Synthesis, purification and assembly of gold and iron oxide nanoparticles

    Science.gov (United States)

    Qiu, Penghe

    The aims of the current research include developing new synthetic strategies to prepare structurally complex gold nanoparticles and new size sorting methods to separate nanoparticles of larger size, as well as studying the assembly of nanoparticles into novel hierarchical structures through both template-assisted and template-free strategies. In the synthesis section of this dissertation (Chapters 2 & 3), a size controllable synthesis of dendritic gold nanoparticles through a seed-mediated process in ethanol is described. The effect of seeds size and shape as well as the carbon chain length of alkylamines on the formation of dendritic structure was investigated. The synthetic strategy developed is capable of forming dendritic structure on various substrates, like flat or rod-like gold particles. In another work, the shape evolution of gold nanoparticles in a seed-mediated growth as well as the kinetics of reduction of HAuCl4 in the presence of seeds was studied. The reduction of the gold precursor by sodium citrate could be greatly accelerated in the presence of seed nanoparticles. Along with the enhanced reaction kinetics, dramatic shape evolution of gold nanoparticles was observed by changing ratios of precursors. In the purification section (Chapter 4), a novel method of separating nanoparticles of different sizes in a viscosity gradient was developed. The viscosity gradient was created with polyvinylpyrrolidone (PVP) aqueous solutions. Previously, such size separation was all achieved in the density gradient, while the hidden contribution of viscosity difference inside the density gradient was not well recognized. Through this work, it is clarified that the viscosity can contribute as importantly as density in the size sorting of nanoparticles through rate zonal centrifuge. It was also demonstrated both experimentally and mathematically that the viscosity gradient is more effective in separation of larger sized nanoparticles. In the assembly section (Chapter 5

  9. Fungus-mediated synthesis of gold nanoparticles: a novel biological approach to nanoparticle synthesis.

    Science.gov (United States)

    Honary, Soheyla; Gharaei-Fathabad, Eshrat; Barabadi, Hamed; Naghibi, Farzaneh

    2013-02-01

    The biological effects of nanoparticles and their uses as molecular probes are research areas of growing interest. The present study demonstrates an eco-friendly biosynthesis of gold nanoparticles. The pure colonies of penicillium aurantiogriseum, penicillium citrinum, and penicillium waksmanii were cultured in fluid czapek dox broth. Then, their supernatants were examined for the ability to produce gold nanoparticles. In this step, 1 mM solution of AuCl added to the reaction matrixes separately. The reactions were performed in a dark environment at 28 degrees C. After 24 hours, it was observed that the color of the solutions turned to dark purple from light yellow. Synthesized gold nanoparticles were characterized by using UV-Visible Spectroscopy, Nano Zeta Sizer, Scanning Electron Microscopy and Fourier transformed infrared spectroscopy. The results showed that the gold nanoparticles were formed fairly uniform with spherical shape with the Z-average diameter of 153.3 nm, 172 nm and 160.1 nm for penicillium aurantiogriseum, penicillium citrinum, and penicillium waksmanii, respectively. The Fourier transformed infrared spectra revealed the presence of different functional groups to gold nanoparticles which were present in the fungal extract. The current approach suggests that the rapid synthesis of nanoparticles would be proper for developing a biological process for mass scale production.

  10. Reaction parameters for controlled sonosynthesis of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez M, A. L. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon esq. Paseo Tollocan s/n, 50120 Toluca, Estado de Mexico (Mexico); Cabrera L, L. I. [UNAM-UAEM, Centro Conjunto de Investigacion en Quimica Sustentable, Km 14.5 Carretera Toluca-Atlacomulco, 50200 San Cayetano-Toluca, Estado de Mexico (Mexico)

    2015-07-01

    The synthesis of gold nanoparticles by sonochemical technique has been previously performed with excellent results. The synthesis has been carried out in the presence of citric acid, a strong reducing agent, which allows the nucleation and growth of gold nanoparticles, at the same time that controls particle size. In this work we report the use of sodium tartrate as a mild reducing agent that allows a better understanding of the effect of the reaction parameters during gold nanoparticle synthesis. A conventional sonication bath (37 k Hz) was used for the sonochemical synthesis. This work focuses on the reaction temperature effect and the effect of sodium tartrate concentration. It was confirmed that particle size, and particle morphology is dependent of these two reaction parameters. Equally, colloidal stabilization was related to reaction temperature and sodium tartrate concentration. It was also determined that Ostwald ripening takes place during sonochemical reaction under our conditions, allowing to understand the mechanism that takes place during synthesis. Gold nanoparticles with main particle size of 17 nm were achieved by this method. Characterization techniques used: Fourier transform infrared spectra (Ftir), X-ray diffraction and Atomic Force Microscope was used in order to determine particle size of the synthetic product of reaction M10c by tapping mode. (Author)

  11. The effects of gold nanoparticles size and concentration on viscosity ...

    African Journals Online (AJOL)

    This study was carried out to investigate viscosity in relation with the temperature, flow activation energy and dielectric properties for 10, 20 and 50 nm gold nanoparticles size (GNPs) in addition to absorption and fluorescence spectra at different concentrations (0.2 × 10-3 to 1 × 10-2%) in an attempt to cover and understand ...

  12. A Novel Biological Synthesis of Gold Nanoparticle by ...

    African Journals Online (AJOL)

    Purpose: To demonstrate eco-friendly biosynthesis of gold nanoparticles by Enterobacteriaceae. Methods: Pure colonies of nine different bacteria from the Enterobacteriaceae family were separated from water and cultured in Luria Bertani broth medium. Their respective supernatants were examined for ability to produce ...

  13. Comparative study of synthesized silver and gold nanoparticles ...

    Indian Academy of Sciences (India)

    Abstract. Nanotechnology is an emerging field in science and technology, which can be applied to synthesize new materials at the nanoscale level. The present investigation aimed at comparing the synthesis, characterization and in vitro anticancer efficacy of synthesized silver and gold nanoparticles using leaves extract of ...

  14. Design and Fabrication of Microfiber Containing Gold Nanoparticles

    DEFF Research Database (Denmark)

    Jørgensen, Mette Marie; Wang, Guanghui; Hu, Dora Juan Juan

    2010-01-01

    We present a simple fabrication method for embedding gold nanoparticles (GNPs) in a microfiber with two main advantages. The GNPs are positioned within the microfiber securing maximum enhancement of the electrical field and protection of the GNPs from the surroundings; moreover incoupling losses...

  15. Electroless deposition of Gold-Platinum Core@ Shell Nanoparticles ...

    Indian Academy of Sciences (India)

    platinum nanoparticlesz (Au@PtNPs) with core@shell structure fabricated on glassy carbon electrode (GCE) by electroless depositionmethod. Initially, gold nanoparticles (AuNPs) were deposited on GCE by reducing HAuCl4 in the presence of ...

  16. Oligothia dendrimers for the formation of gold nanoparticles

    NARCIS (Netherlands)

    d'Aleo, A.; Williams, R.M.; Osswald, F.; Edamana, P.; Hahn, U.; van Heyst, J.; Tichelaar, F.D.; Voegtle, F.; De Cola, L.

    2004-01-01

    The synthesis and characterization of oligothia dendrimers and their use for the formation of gold nanoparticles is described. The role played by these dendrimers in controlling the stability and size of the particles is discussed. It is shown that the generation of the dendrimers, as well as the

  17. Electrospun fibre colorimetric probe based on gold nanoparticles for ...

    African Journals Online (AJOL)

    2014-11-20

    Nov 20, 2014 ... An on-site colorimetric probe, based on gold nanoparticles incorporated into electrospun polystyrene nanofibres, for the detection of oestrogenic compounds, as represented by 17β-estradiol, in dairy effluents is presented. The probe exhibited a significant absorption peak at 542 nm, ascribed to surface ...

  18. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

    2014-01-01

    With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite‐1 is reported and their high ...

  19. Electrospun fibre colorimetric probe based on gold nanoparticles for ...

    African Journals Online (AJOL)

    An on-site colorimetric probe, based on gold nanoparticles incorporated into electrospun polystyrene nanofibres, for the detection of oestrogenic compounds, as represented by 17β-estradiol, in dairy effluents is presented. The probe exhibited a significant absorption peak at 542 nm, ascribed to surface plasmon resonance ...

  20. The bioaccumulation and toxicity induced by gold nanoparticles in ...

    African Journals Online (AJOL)

    It is essential to characterize the bioaccumulation and toxicity of gold nanoparticles (GNPs) in blood prior to using them in drug delivery, diagnostics, and treatment. The aim of the present study was to evaluate the blood absorbance spectra after intraperitoneal administration of 50 μl of 10, 20, and 50 nm GNPs in rat for ...

  1. Electronic shell structure and chemisorption on gold nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Ask Hjorth; Kleis, Jesper; Thygesen, Kristian Sommer

    2011-01-01

    We use density functional theory (DFT) to investigate the electronic structure and chemical properties of gold nanoparticles. Different structural families of clusters are compared. For up to 60 atoms we optimize structures using DFT-based simulated annealing. Cluster geometries are found...

  2. Light-Driven Rotary Molecular Motors on Gold Nanoparticles

    NARCIS (Netherlands)

    Pollard, Michael M.; ter Wiel, Matthijs K. J.; van Delden, Richard A.; Vicario, Javier; Koumura, Nagatoshi; van den Brom, Coenraad R.; Meetsma, Auke; Feringa, Ben L.

    2008-01-01

    We report the synthesis of unidirectional light-driven rotary molecular motors based oil chiral overcrowded alkenes and their immobilisation on the surface of gold nanoparticles through two anchors. Using a combination of (1)H and (13)C NMR, UV/Vis and CD spectroscopy, we show that these motors

  3. Comparative study of synthesized silver and gold nanoparticles ...

    Indian Academy of Sciences (India)

    Nanotechnology is an emerging field in science and technology, which can be applied to synthesize new materials at the nanoscale level. The present investigation aimed at comparing the synthesis, characterization andin vitro anticancer efficacy of synthesized silver and gold nanoparticles using leaves extract of Bauhinia ...

  4. Gold Nanoparticles: Recent Advances in the Biomedical Applications.

    Science.gov (United States)

    Zhang, Xiaoying

    2015-07-01

    Among the multiple branches of nanotechnology applications in the area of medicine and biology, Nanoparticle technology is the fastest growing and shows significant future promise. Nanoscale structures, with size similar to many biological molecules, show different physical and chemical properties compared to either small molecules or bulk materials, find many applications in the fields of biomedical imaging and therapy. Gold nanoparticles (AuNPs) are relatively inert in biological environment, and have a number of physical properties that are suitable for several biomedical applications. For example, AuNPs have been successfully employed in inducing localized hyperthermia for the destruction of tumors or radiotherapy for cancer, photodynamic therapy, computed tomography imaging, as drug carriers to tumors, bio-labeling through single particle detection by electron microscopy and in photothermal microscopy. Recent advances in synthetic chemistry makes it possible to make gold nanoparticles with precise control over physicochemical and optical properties that are desired for specific clinical or biological applications. Because of the availability of several methods for easy modification of the surface of gold nanoparticles for attaching a ligand, drug or other targeting molecules, AuNPs are useful in a wide variety of applications. Even though gold is biologically inert and thus shows much less toxicity, the relatively low rate of clearance from circulation and tissues can lead to health problems and therefore, specific targeting of diseased cells and tissues must be achieved before AuNPs find their application for routine human use.

  5. Ligand adsorption and exchange on pegylated gold nanoparticles

    Science.gov (United States)

    Previous researchers proposed that thiolated poly(ethylene glycol) (PEG-SH) adopts a “mushroom-like” conformation on gold nanoparticles (AuNPs) in water. However, information regarding the size and permeability of the PEG-SH mushroom caps and surface area passivated by the PEG-SH mushroom stems are ...

  6. The epoxidation of propene over gold nanoparticle catalysts

    NARCIS (Netherlands)

    Nijhuis, T.A.; Sacaliuc, E.; Weckhuysen, B.M.

    2008-01-01

    Different gold nanoparticle catalysts on titania, silica, and titanosilicate supports are compared in the hydro-epoxidation of propene. All catalysts tested were active in the propene epoxidation, with Au/TiO2 showing the highest activity at low temperature, but also a high rate of deactivation. It

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

    Science.gov (United States)

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

    2014-05-05

    Gold-containing polymer nanotubes, which showed both catalytic activity and resistance to leaching, were prepared by the "tubes by fiber templates" (TUFT) process. For this purpose, electrospun polymer nonwovens with incorporated poly(L-lactide)-stabilized gold nanoparticles were coated with poly(p-xylylene) by the chemical vapor deposition process, and then the inner fiber templates were removed. The resulting polymer tubes carried encapsulated gold nanoparticles which were shown to be immobilized and featured pronounced catalytic activity towards the hydrolytic oxidation of dimethylphenylsilane and the alcoholysis of dimethylphenylsilane with n-butanol. The macroscopic nonwovens could be used as tea-bag-like catalyst systems and showed excellent reusability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Synthesis, Structure, Stability and Redispersion of Gold-based Nanoparticles

    Science.gov (United States)

    Tiruvalam, Ram Chandra

    Nanoscale gold has been shown to possess an intriguing combination of unexpected optical, photochemical and catalytic properties. The ability to control the size, shape, morphology, composition and dispersion of gold-based nanostructures is key to optimizing their performance for nanotechnology applications. The advanced electron microscopy studies described in this thesis analyze three important aspects of gold and gold-palladium alloy nanoparticles: namely, (i) the ability to synthesize gold nanoparticles of controlled size and shape in an aqueous medium; (ii) the colloidal preparation of designer gold-palladium alloys for selective oxidation catalysis; and (iii) the ability to disperse gold as finely and homogeneously as possible on a metal oxide or carbon support. The ability to exploit the nanoscale properties of gold for various engineering applications often depends on our ability to control size and shape of the nanoscale entity by careful manipulation of the synthesis parameters. We have explored an aqueous based synthesis route, using oleylamine as both a reductant and surfactant, for preparing gold nanostructures. By systematically varying synthesis parameters such as oleylamine concentration, reaction temperature, and aging time it is possible to identify processing regimens that generate Au nanostructures having either pseudo-spherical, faceted polyhedral, nanostar or wire shaped morphologies. Furthermore, by quenching the reaction partway through it is possible to create a class of metastable Au-containing structures such as nanocubes, nanoboxes and nanowires. Possible formation mechanisms for these gold based nano-objects are discussed. There is a growing interest in using supported bimetallic AuPd alloy nanoparticles for selective oxidation reactions. In this study, a systematic series of size controlled AuPd bimetallic particles have been prepared by colloidal synthesis methods. Particles having random alloy structures, as well as `designer

  9. Defining rules for the shape evolution of gold nanoparticles.

    Science.gov (United States)

    Langille, Mark R; Personick, Michelle L; Zhang, Jian; Mirkin, Chad A

    2012-09-05

    The roles of silver ions and halides (chloride, bromide, and iodide) in the seed-mediated synthesis of gold nanostructures have been investigated, and their influence on the growth of 10 classes of nanoparticles that differ in shape has been determined. We systematically studied the effects that each chemical component has on the particle shape, on the rate of particle formation, and on the chemical composition of the particle surface. We demonstrate that halides can be used to (1) adjust the reduction potential of the gold ion species in solution and (2) passivate the gold nanoparticle surface, both of which control the reaction kinetics and thus enable the selective synthesis of a series of different particle shapes. We also show that silver ions can be used as an underpotential deposition agent to access a different set of particle shapes by controlling growth of the resulting gold nanoparticles through surface passivation (more so than kinetic effects). Importantly, we show that the density of silver coverage can be controlled by the amount and type of halide present in solution. This behavior arises from the decreasing stability of the underpotentially deposited silver layer in the presence of larger halides due to the relative strengths of the Ag(+)/Ag(0)-halide and Au(+)/Au(0)-halide interactions, as well as the passivation effects of the halides on the gold particle surface. We summarize this work by proposing a set of design considerations for controlling the growth and final shape of gold nanoparticles prepared by seed-mediated syntheses through the judicious use of halides and silver ions.

  10. Aggregation behaviour of gold nanoparticles in presence of chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Collado-González, Mar; Fernández Espín, Vanesa [University of Murcia, Department of Physical Chemistry (Spain); Montalbán, Mercedes G. [University of Murcia, Department of Chemical Engineering (Spain); Pamies, Ramón [Technical University of Cartagena, Department of Material Engineering and Manufacturing (Spain); Hernández Cifre, José Ginés; Díaz Baños, F. Guillermo, E-mail: fgb@um.es [University of Murcia, Department of Physical Chemistry (Spain); Víllora, Gloria [University of Murcia, Department of Chemical Engineering (Spain); García de la Torre, José [University of Murcia, Department of Physical Chemistry (Spain)

    2015-06-15

    Chitosan (CS) is a biocompatible polysaccharide with positive charge that is widely used as a coating agent for negatively charged nanoparticles. However, the types of structures that emerge by combining CS and nanoparticles as well as their behaviour are still poorly understood. In this work, we characterize the nanocomposites formed by gold nanoparticles (AuNPs) and CS and study the influence of CS in the expected aggregation process that should experience those nanoparticles under the favourable conditions of low pH and high ionic strength. Thus, at the working CS concentration, we observe the existence of CS structures that quickly trap the AuNPs and avoid the formation of nanoparticle aggregates in environmental conditions that, otherwise, would lead to such an aggregation.

  11. Irradiated chitosan nanoparticle as a water-based antioxidant and reducing agent for a green synthesis of gold nanoplatforms

    Science.gov (United States)

    Pasanphan, Wanvimol; Rattanawongwiboon, Thitirat; Choofong, Surakarn; Güven, Olgun; Katti, Kattesh K.

    2015-01-01

    The idea of preparing water-soluble chitosan and observing its nanostructural morphology are proposed using irradiation process. The water-soluble chitosan nanoparticles (WSCS-NPs) properties were assessed for a possible use as an antioxidant and reducing agent for a green synthesis of gold nanoparticles (AuNPs). The characteristics of WSCS-NPs were verified using FT-IR, XRD, C H N analyzer and TGA. The nanostructural morphology was investigated using SEM and TEM. The number average molecular weight of WSCS-NPs was as low as 3800 g/mol with narrow polydispersity of 1.26. The average hydrodynamic diameter of WSCS-NPs was 15.40±0.47 nm. The 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity of WSCS-NPs at 0.1 mg/mL was up to 80%, while the original CS exhibited no antioxidant activity. An effective concentration of WSCS-NPs to reduce DPPH free radicals (150 μM) by 50% is as low as 0.025 mg/mL. The in vitro cytotoxicity test by MTT assay demonstrated that WSCS-NPs are non-toxic with an IC50 of 2000 μg/mL. The WSCS-NPs are efficient reducing and stabilizing agent for producing stable colloidal AuNPs. The achievement of the WSCS-NPs and its ability to create AuNPs would be a part of growing interest of green nanotechnology in biomedicine.

  12. In situ gold-nanoparticle electrogeneration on gold films deposited on paper for non-enzymatic electrochemical determination of glucose.

    Science.gov (United States)

    Núnez-Bajo, Estefanía; Blanco-López, M Carmen; Costa-García, Agustín; Fernández-Abedul, M Teresa

    2018-02-01

    This work describes the development and evaluation of a new electrochemical platform based on the sustainable generation of gold-nanoparticles on paper-based gold-sputtered electrodes. The disposable porous paper electrode is combined with screen-printed electrodes for ensuring a precise electrogeneration of nanoparticles and also for the evaluation of these simple, versatile and low-cost microfluidic devices. Two types of chromatographic paper with different thicknesses have been evaluated. Paper gold working electrodes modified with gold nanoparticles were characterized by scanning electron microscopy and cyclic voltammetry using potassium ferrocyanide as a common redox probe, showing an improved electrochemical performance when compared to bare gold electrodes. The platform has been applied to the non-enzymatic determination of glucose, molecule of enormous interest. The porous gold structure made by sputtering on paper, modified with electrogenerated nanoparticles allowed precise and accurate determination of the analyte in beverages at low potential. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. SDS bubbles functionalized with Gold nanoparticles and SERS applications

    Science.gov (United States)

    Navarro-Badilla, A.; Hurtado, R. Britto; Cortez-Valadez, M.; Perez-Rodriguez, A.; Flores-Acosta, M.; Maldonado-Arce, A.

    2017-03-01

    We present a method of incorporation of gold nanoparticles in SDS (sodium dodecyl sulfate) bubbles with a low polydispersity index (monodispersed nanoparticles). Both the bubbles and nanoparticles maintained their structural and morphologic properties after functionalization. The bubbles present a radio of 0.38 mm with a standard deviation of±0.018 mm. The gold nanoparticles were obtained with sucrose as the catalytic agent and ascorbic acid as the reducing agent. The nanoparticles display several geometric morphologies as well as sizes inferior to 50 nm, as observed in the images obtained with Transmission Electron Microscopy (TEM). The optical properties were studied by optical absorption spectroscopy. The absorption band linked to the surface plasmon resonance (SPR) is located at 550 nm before and after the functionalization of the bubbles. Moreover, microscopic bubbles with a diameter smaller than 1 μm with the ability to stabilize nanoparticles in their surface were found in isolated regions of the sample. Additionally, the Surface Enhancement Raman Spectroscopy (SERS) properties of the colloid were analyzed with common drugs.

  14. Photothermal lens detection of gold nanoparticles: theory and experiments.

    Science.gov (United States)

    Brusnichkin, Anton V; Nedosekin, Dmitry A; Proskurnin, Mikhail A; Zharov, Vladimir P

    2007-11-01

    An approach for mode-mismatched two-beam (pump-probe) photothermal lens detection of multipoint light-absorbing targets in solution (e.g., gold nanoparticles) is developed for continuous-wave intensity-modulated laser-excitation mode. A description of the blooming of the thermooptical element (thermal lens) upon absorption of the excitation laser radiation is based on the summation of individual thermal waves from multiple heat sources. This description makes it possible to estimate the irregularities of the temperature (and, thus, the refractive index) profile for a discrete number of nanoparticles in the irradiated area and a change in the concentration and particle size parameters. Experimental results are in good agreement with theoretical dependences of the photothermal signal on nanoparticle size and concentration and excitation laser power. Calibration plots for particles from 2 to 250 nm show long linear ranges, limits of detection of gold nanoparticles at the level of hundreds of nanoparticles with the current setup, and the photothermal-lens sensitivity coefficient increases as a cubic function of particle size. Further improvements are discussed, including increasing the sensitivity thresholds up to one nanoparticle in the detected volume.

  15. Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis

    Science.gov (United States)

    Petkova, Galina A.; Záruba, Кamil; Žvátora, Pavel; Král, Vladimír

    2012-06-01

    In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective ( ee > 99%) synthesis of ( S)-7-hydroxy-2-tetralol.

  16. Pair distribution function analysis applied to decahedral gold nanoparticles

    Science.gov (United States)

    Nakotte, H.; Silkwood, C.; Page, K.; Wang, H.-W.; Olds, D.; Kiefer, B.; Manna, S.; Karpov, D.; Fohtung, E.; Fullerton, E. E.

    2017-11-01

    The five-fold symmetry of face-centered cubic (fcc) derived nanoparticles is inconsistent with the translational symmetry of a Bravais lattice and generally explained by multiple twinning of a tetrahedral subunit about a (joint) symmetry axis, with or without structural modification to the fcc motif. Unlike in bulk materials, five-fold twinning in cubic nanoparticles is common and strongly affects their structural, chemical, and electronic properties. To test and verify theoretical approaches, it is therefore pertinent that the local structural features of such materials can be fully characterized. The small size of nanoparticles severely limits the application of traditional analysis techniques, such as Bragg diffraction. A complete description of the atomic arrangement in nanoparticles therefore requires a departure from the concept of translational symmetry, and prevents fully evaluating all the structural features experimentally. We describe how recent advances in instrumentation, together with the increasing power of computing, are shaping the development of alternative analysis methods of scattering data for nanostructures. We present the application of Debye scattering and pair distribution function (PDF) analysis towards modeling of the total scattering data for the example of decahedral gold nanoparticles. PDF measurements provide a statistical description of the pair correlations of atoms within a material, allowing one to evaluate the probability of finding two atoms within a given distance. We explored the sensitivity of existing synchrotron x-ray PDF instruments for distinguishing four different simple models for our gold nanoparticles: a multiply twinned fcc decahedron with either a single gap or multiple distributed gaps, a relaxed body-centered orthorhombic (bco) decahedron, and a hybrid decahedron. The data simulations of the models were then compared with experimental data from synchrotron x-ray total scattering. We present our experimentally

  17. Preparation of Radioactive Gold Nanoparticle by Neutron Activation

    Directory of Open Access Journals (Sweden)

    Rohadi Awaludin

    2010-10-01

    Full Text Available It was reported that gold nanoparticle could be used for cancer therapy using thermal effect. It is possible to kill cancer cells using radiation of radioisotope. Study on preparation of radioactive gold by neutron activation at central irradiation position (CIP of G.A. Siwabessy reactor with neutron flux 1.26 x 1014 neutron s-1cm-2 has been carried out. It was revealed that a radioisotop of gold (198Au was produced by neutron activation from natural gold. Calculation results showed that 198Au with radioactivity of 0.366 Bq, 2.93 Bq, 9.90 Bq and 23.4 Bq was produced for nanoparticle with diameter of 100, 200, 300 and 400 nm by neutron irradiation for 12 days. The saturation factor was 96.5%. After 10 days of decay, the radioactivity was 0.027 Bq, 0.223 Bq, 0.753 Bq and 1.78 Bq in nanoparticle with diameter of 100, 200, 300 and 400 nm. The radionuclide impurities were 108Ag, 110mAg, 64Cu, 66Cu, 205Pb and 209Pb with the total radioactivity was 4.31 x 10-5 % of the total radioactivity of 198Au at the end of irradiation.

  18. Gold and silver nanoparticles from Trianthema decandra: synthesis, characterization, and antimicrobial properties

    Science.gov (United States)

    Geethalakshmi, R; Sarada, DVL

    2012-01-01

    Background There is an increasing commercial demand for nanoparticles due to their wide applicability in various markets, including medicine, catalysis, electronics, chemistry, and energy. In this report, a simple and ecofriendly chemical reaction for the synthesis of gold and silver nanoparticles from Trianthema decandra (Aizoaceae) has been developed. Methods and results On treatment of aqueous solutions containing chloroauric acid or silver nitrate with root extract of T. decandra, stable gold or silver nanoparticles were rapidly formed. The kinetics of reduction of gold and silver ions during the reaction was analyzed by ultraviolet-visible spectroscopy. Field emission-scanning electron microscopy showed formation of gold nanoparticles in various shapes, including spherical, cubical, triangular, and hexagonal, while silver nanoparticles were spherical. The size of the gold nanoparticles was 33–65 nm and that of the silver nanoparticles was 36–74 nm. Energy dispersive x-ray and Fourier transform infrared spectroscopy confirmed the presence of metallic gold and metallic silver in the respective nanoparticles. The antimicrobial properties of the synthesized nanoparticles were analyzed using the Kirby-Bauer method. The results show varied susceptibility of microorganisms to the gold and silver nanoparticles. Conclusion It is believed that phytochemicals present in T. decandra extract reduce the silver and gold ions into metallic nanoparticles. This strategy reduces the cost of production and the environmental impact. The silver and gold nanoparticles formed showed strong activity against all microorganisms tested. PMID:23091381

  19. Gold and silver nanoparticles from Trianthema decandra: synthesis, characterization, and antimicrobial properties.

    Science.gov (United States)

    Geethalakshmi, R; Sarada, D V L

    2012-01-01

    There is an increasing commercial demand for nanoparticles due to their wide applicability in various markets, including medicine, catalysis, electronics, chemistry, and energy. In this report, a simple and ecofriendly chemical reaction for the synthesis of gold and silver nanoparticles from Trianthema decandra (Aizoaceae) has been developed. On treatment of aqueous solutions containing chloroauric acid or silver nitrate with root extract of T. decandra, stable gold or silver nanoparticles were rapidly formed. The kinetics of reduction of gold and silver ions during the reaction was analyzed by ultraviolet-visible spectroscopy. Field emission-scanning electron microscopy showed formation of gold nanoparticles in various shapes, including spherical, cubical, triangular, and hexagonal, while silver nanoparticles were spherical. The size of the gold nanoparticles was 33-65 nm and that of the silver nanoparticles was 36-74 nm. Energy dispersive x-ray and Fourier transform infrared spectroscopy confirmed the presence of metallic gold and metallic silver in the respective nanoparticles. The antimicrobial properties of the synthesized nanoparticles were analyzed using the Kirby-Bauer method. The results show varied susceptibility of microorganisms to the gold and silver nanoparticles. It is believed that phytochemicals present in T. decandra extract reduce the silver and gold ions into metallic nanoparticles. This strategy reduces the cost of production and the environmental impact. The silver and gold nanoparticles formed showed strong activity against all microorganisms tested.

  20. Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro

    Science.gov (United States)

    Speshock, Janice L.; Braydich-Stolle, Laura K.; Szymanski, Eric R.; Hussain, Saber M.

    2011-12-01

    Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material.

  1. Covalent assembly of gold nanoparticles for nonvolatile memory applications.

    Science.gov (United States)

    Gupta, Raju Kumar; Kusuma, Damar Yoga; Lee, P S; Srinivasan, M P

    2011-12-01

    This work reports a versatile approach for enhancing the stability of nonvolatile memory devices through covalent assembly of functionalized gold nanoparticles. 11-mercapto-1-undecanol functionalized gold nanoparticles (AuNPs) with a narrow size distribution and particle size of about 5 nm were synthesized. Then, the AuNPs were immobilized on a SiO(2) substrate using a functionalized polymer as a surface modifier. Microscopic and spectroscopic techniques were used to characterize the AuNPs and their morphology before and after immobilization. Finally, a metal-insulator-semiconductor (MIS) type memory device with such covalently anchored AuNPs as a charge trapping layer was fabricated. The MIS structure showed well-defined counterclockwise C-V hysteresis curves indicating a good memory effect. The flat band voltage shift was 1.64 V at a swapping voltage between ±7 V. Furthermore, the MIS structure showed a good retention characteristic up to 20,000 s. The present synthetic route to covalently immobilize gold nanoparticles system will be a step towards realization for the nanoparticle-based electronic devices and related applications. © 2011 American Chemical Society

  2. Label-free aptamer-based colorimetric detection of mercury ions in aqueous media using unmodified gold nanoparticles as colorimetric probe.

    Science.gov (United States)

    Li, Li; Li, Baoxin; Qi, Yingying; Jin, Yan

    2009-04-01

    We report a simple and sensitive aptamer-based colorimetric detection of mercury ions (Hg(2+)) using unmodified gold nanoparticles as colorimetric probe. It is based on the fact that bare gold nanoparticles interact differently with short single-strand DNA and double-stranded DNA. The anti-Hg(2+) aptamer is rich in thymine (T) and readily forms T-Hg(2+)-T configuration in the presence of Hg(2+). By measuring color change or adsorption ratio, the bare gold nanoparticles can effectively differentiate the Hg(2+)-induced conformational change of the aptamer in the presence of a given salt with high concentration. The assay shows a linear response toward Hg(2+) concentration through a five-decade range of 1 x 10(-4) mol L(-1) to 1 x 10(-9) mol L(-1). Even with the naked eye, we could identify micromolar Hg(2+) concentrations within minutes. By using the spectrometric method, the detection limit was improved to the nanomolar range (0.6 nM). The assay shows excellent selectivity for Hg(2+) over other metal cations including K(+), Ba(2+), Ni(2+), Pb(2+), Cu(2+), Cd(2+), Mg(2+), Ca(2+), Zn(2+), Al(3+), and Fe(3+). The major advantages of this Hg(2+) assay are its water-solubility, simplicity, low cost, visual colorimetry, and high sensitivity. This method provides a potentially useful tool for the Hg(2+) detection.

  3. Gold Nanoparticles as the Catalyst of Single-Walled Carbon Nanotube Synthesis

    Directory of Open Access Journals (Sweden)

    Yoshikazu Homma

    2014-03-01

    Full Text Available Gold nanoparticles have been proven to act as efficient catalysts for chemical reactions, such as oxidation and hydrogen production. In this review we focus on a different aspect of the catalysis of gold nanoparticles; single-walled carbon nanotube (SWCNT synthesis. This is not a traditional meaning of catalytic reaction, but SWCNTs cannot be synthesized without nanoparticles. Previously, gold was considered as unsuitable metal species as the catalyst of SWCNT synthesis. However, gold nanoparticles with diameters smaller than 5 nm were found to effectively produce SWCNTs. We discuss the catalysis of gold and related metals for SWCNT synthesis in comparison with conventional catalysts, such as iron, cobalt, and nickel.

  4. Simple Recovery of Intracellular Gold Nanoparticles from Peanut Seedling Roots.

    Science.gov (United States)

    Raju, D; Mehta, Urmil J; Ahmad, Absar

    2015-02-01

    Fabrication of inorganic nanomaterials via a biological route witnesses the formation either extracellularly, intracellulary or both. Whereas extracellular formation of these nanomaterials is cherished owing to their easy and economical extraction and purification processes; the intracellular formation of nanomaterials, due to the lack of a proper recovery protocol has always been dreaded, as the extraction processes used so far were tedious, costly, time consuming and often resulting in very low recovery. The aim of the present study was to overcome the problems related with the extraction and recovery of intracellularly synthesized inorganic nanoparticles, and to devise a method to increasing the output, the shape, size, composition and dispersal of nanoparticles is not altered. Water proved to be much better system as it provided well dispersed, stable gold nanoparticles and higher recovery. This is the first report, where intracellular nanoparticles have been recovered using a very cost-effective and eco-friendly approach.

  5. Catalase coupled gold nanoparticles: Comparison between carbodiimide and biotin-streptavidin methods

    Science.gov (United States)

    Chirra, Hariharasudhan D.; Sexton, Travis; Biswal, Dipti; Hersh, Louis B.; Hilt, J. Zach

    2011-01-01

    The use of proteins for therapeutic applications requires the protein to maintain sufficient activity for the period of in vivo treatment. Many proteins exhibit a short half-life in vivo and, thus, require delivery systems for them to be applied as therapeutics. The relative biocompatibility and the ability to form functionalized bioconjugates via simple chemistry make gold nanoparticles excellent candidates as protein delivery systems. Herein, two protocols for coupling proteins to gold nanoparticles were compared. In the first, the strong biomolecular binding between biotin and streptavidin was used to couple catalase to the surface of gold nanoparticles. In the second protocol, the formation of an amide bond between carboxylic acid coated gold nanoparticles and free surface amines of catalase using carbodiimide chemistry was performed. The stability and kinetics of the different steps involved in these protocols were studied using UV-Visible spectroscopy, dynamic light scattering, and transmission electron microscopy. The addition of mercaptoundecanoic acid in conjugation with (N-(6-(biotinamido)hexyl)-3′-(2′-pyridyldithio)-propionamide increased the stability of biotinylated gold nanoparticles. Although the carbodiimide chemistry based bioconjugation approach exhibited a decrease in catalase activity, the carbodiimide chemistry based bioconjugation approach resulted in more active catalase per gold nanoparticle compared to that of mercaptoundecanoic acid stabilized biotinylated gold nanoparticles. Both coupling protocols resulted in gold nanoparticles loaded with active catalase. Thus, these gold nanoparticle systems and coupling protocols represent promising methods for the application of gold nanoparticles for protein delivery. PMID:21232642

  6. Synthesis of netlike gold nanoparticles using ampicillin as a stabilizing reagent and its application

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y.Z., E-mail: singyuanzhi@sina.com [Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai An 223300 (China); Zhou, J.F. [Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai An 223300 (China); Song, Y., E-mail: songyang@mail.buct.edu.cn [College of Materials Science and Engineering, Beijing University of Chemical Technology, Peking 100029 (China); Cheng, Z.P. [Jiangsu Province Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai An 223300 (China); Xu, J. [Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2012-12-15

    Graphical abstract: Electrochemical deposition of netlike gold nanoparticles (GNPs) on the surface of glassy carbon electrode and preparation of netlike GNPs in aqueous solution using ampicillin as a stabilizing reagent were proposed. The catalytic properties of netlike gold nanoparticles on the glassy carbon electrode for dopamine were demonstrated. The results indicate that the netlike gold nanoparticle modified electrode has an excellent repeatability and reproducibility. Display Omitted Highlights: ► Synthesis of netlike gold nanoparticles using ampicillin as a stabilizing reagent. ► Excellent repeatability and reproducibility of netlike gold nanoparticle modified glassy carbon electrode. ► The catalytic properties of netlike gold nanoparticle for dopamine. -- Abstract: Electrochemical deposition of netlike gold nanoparticles on the surface of glassy carbon electrode and preparation of netlike GNPs in aqueous solution using ampicillin as a stabilizing reagent were proposed. The netlike gold nanoparticles were characterized by scanning electron microscope, transmission electron microscope, infrared spectrometer, UV spectrophotometer, powder X-ray diffractometer and electrochemical analyzer. The catalysis of the netlike gold nanoparticles on the glassy carbon electrode for dopamine was demonstrated. The results indicate that the gold nanoparticle modified electrode has an excellent repeatability and reproducibility.

  7. Functionalization of Biosynthesized Gold Nanoparticle from ...

    African Journals Online (AJOL)

    Dr Olaleye

    Nanomedicine is the interaction between the field of nanotechnology and medicine, which is concerned with the use of precisely engineered materials at the nanoscale to develop novel therapeutic and diagnostic modalities. Nanoparticles are particles with size range within the nanoscale, which exhibit new properties such ...

  8. Dielectrophoresis of gold nanoparticles conjugated to DNA origami structures

    Directory of Open Access Journals (Sweden)

    Anja Henning-Knechtel

    2016-07-01

    Full Text Available DNA nanostructures are promising construction materials to bridge the gap between self-assembly of functional molecules and conventional top-down fabrication methods in nanotechnology. Their positioning onto specific locations of a microstructured substrate is an important task towards this aim. Here we study manipulation and positioning of pristine and of gold nanoparticle-conjugated tubular DNA origami structures using ac dielectrophoresis. The dielectrophoretic behavior was investigated employing fluorescence microscopy. For the pristine origami, a significant dielectrophoretic response was found to take place in the megahertz range, whereas, due to the higher polarizability of the metallic nanoparticles, the nanoparticle/DNA hybrid structures required a lower electrical field strength and frequency for a comparable trapping at the edges of the electrode structure. The nanoparticle conjugation additionally resulted in a remarkable alteration of the DNA structure arrangement. The growth of linear, chain-like structures in between electrodes at applied frequencies in the megahertz range was observed. The long-range chain formation is caused by a local, gold nanoparticle-induced field concentration along the DNA nanostructures, which in turn, creates dielectrophoretic forces that enable the observed self-alignment of the hybrid structures.

  9. Antibacterial nanocarriers of resveratrol with gold and silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sohyun [College of Pharmacy, Inje University, 197 Inje-ro Gimhae, Gyeongnam 621-749 (Korea, Republic of); Cha, Song-Hyun [National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Cho, Inyoung [School of Civil, Environmental and Architecture Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Park, Soomin [National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Yohan [College of Pharmacy, Inje University, 197 Inje-ro Gimhae, Gyeongnam 621-749 (Korea, Republic of); Cho, Seonho [National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Youmie, E-mail: youmiep@inje.ac.kr [College of Pharmacy, Inje University, 197 Inje-ro Gimhae, Gyeongnam 621-749 (Korea, Republic of); National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2016-01-01

    This study focused on the preparation of resveratrol nanocarrier systems and the evaluation of their in vitro antibacterial activities. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) for resveratrol nanocarrier systems were synthesized using green synthetic routes. During the synthesis steps, resveratrol was utilized as a reducing agent to chemically reduce gold and silver ions to AuNPs and AgNPs. This system provides green and eco-friendly synthesis routes that do not involve additional chemical reducing agents. Resveratrol nanocarriers with AuNPs (Res-AuNPs) and AgNPs (Res-AgNPs) were observed to be spherical and to exhibit characteristic surface plasmon resonance at 547 nm and at 412–417 nm, respectively. The mean size of the nanoparticles ranged from 8.32 to 21.84 nm, as determined by high-resolution transmission electron microscopy. The face-centered cubic structure of the Res-AuNPs was confirmed by high-resolution X-ray diffraction. Fourier-transform infrared spectra indicated that the hydroxyl groups and C=C in the aromatic ring of resveratrol were involved in the reduction reaction. Res-AuNPs retained excellent colloidal stability during ultracentrifugation and re-dispersion, suggesting that resveratrol also played a role as a capping agent. Zeta potentials of Res-AuNPs and Res-AgNPs were in the range of − 20.58 to − 48.54 mV. Generally, against Gram-positive and Gram-negative bacteria, the Res-AuNPs and Res-AgNPs exhibited greater antibacterial activity compared to that of resveratrol alone. Among the tested strains, the highest antibacterial activity of the Res-AuNPs was observed against Streptococcus pneumoniae. The addition of sodium dodecyl sulfate during the synthesis of Res-AgNPs slightly increased their antibacterial activity. These results suggest that the newly developed resveratrol nanocarrier systems with metallic nanoparticles show potential for application as nano-antibacterial agents with enhanced activities. - Highlights

  10. Role of Gold Nanoparticles in Early Detection of Oral Cancer

    Directory of Open Access Journals (Sweden)

    P Sanjay Reddy

    2010-01-01

    Nanotechnology is the science of the small; the very small. It is the use and manipulation of matter at a tiny scale. At this size, atoms and molecules work differently and provide a variety of surprising and interesting uses. These nanoparticles can be used to detect/mondor cancer (by utilizing or adding optical, magnetic, and fluorescent properties. This novel imaging tool can lead to significant improvements in cancer therapy due to earlier detection, accurate staging and microtumor identification. In this review, we will summarize the current state of the art of gold nanoparticles in early detection of oral cancer.

  11. Poly-thiosemicarbazide Membrane for Gold Adsorption and In-situ Growth of Gold Nanoparticles

    KAUST Repository

    Parra, Luis F.

    2012-12-01

    In this work the synergy between a polymer containing chelate sites and gold ions was explored by the fabrication of a polymeric membrane with embedded gold nanoparticles inside its matrix and by developing a process to recover gold from acidic solutions. After realizing that the thiosemicarbazide groups present in the monomeric unit of poly-thiosemicarbazide (PTSC) formed strong complexes with Au ions, membrane technology was used to exploit this property to its maximum. The incorporation of metal nanoparticles into polymeric matrices with current technologies involves either expensive and complicated procedures or leads to poor results in terms of agglomeration, loading, dispersion, stability or efficient use of raw materials. The fabrication procedure described in this thesis solves these problems by fabricating a PTSC membrane containing 33.5 wt% in the form of 2.9 nm gold nanoparticles (AuNPs) by a three step simple and scalable procedure. It showed outstanding results in all of the areas mentioned above and demonstrated catalytic activity for the reduction of 4-Nitrophenol (4−NP) to 4-Aminophenol (4−AP). The current exponential demand of gold for electronics has encouraged the development of efficient processes to recycle it. Several adsorbents used to recover gold from acidic solutions can be found in the literature with outstanding maximum uptakes,yet, poor kinetics leading to an overall inefficient process. The method developed in this dissertation consisted in permeating the gold-containing solution through a PTSC membrane that will capture all the Au ions by forming a metal complex with them. Forcing the ions through the pores of the membrane eliminates the diffusion limitations and the adsorption will only depended on the fast complexation kinetics, resulting in a very efficient process. A flux as high as 1868 L/h m2 was enough to capture >90% of the precious metal present in a solution of 100 ppm Au. The maximum uptake achieved without sacrificing

  12. Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

    Science.gov (United States)

    Tsai, Tsung-Ting; Shen, Shu-Wei; Cheng, Chao-Min; Chen, Chien-Fu

    2013-08-01

    A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h.

  13. Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Tsung-Ting Tsai, Shu-Wei Shen, Chao-Min Cheng and Chien-Fu Chen

    2013-01-01

    Full Text Available A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h.

  14. Water-Soluble Metallocene-Containing Polymers.

    Science.gov (United States)

    Alkan, Arda; Wurm, Frederik R

    2016-09-01

    Metallocenes are organometallic compounds with reversible redox profiles and tunable oxidation and reduction potentials, depending on the metal and substituents at the cyclopentadienyl rings. Metallocenes have been introduced in macromolecules to combine the redox-activity with polymer properties. There are many examples of such hydrophobic polymer materials, but much fewer water-soluble examples are found scattered across the polymer literature. However, in terms of drug delivery and other biological applications, water solubility is essential. For this very reason, all the synthetic routes to water-soluble metallocene containing polymers are collected and discussed here. The focus is on neutral ferrocene- and ruthenocene-containing and charged cobaltocenium-containing macromolecules (i.e., symmetrical sandwich complexes). The synthetic protocols, self-assembly behavior, and other benefits of the obtained materials are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Graphene-Gold Nanoparticles Hybrid-Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor.

    Science.gov (United States)

    Khalil, Ibrahim; Julkapli, Nurhidayatullaili Muhd; Yehye, Wageeh A; Basirun, Wan Jefrey; Bhargava, Suresh K

    2016-05-24

    Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS) with graphene produces the graphene-AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene-Au nanocomposites. The paper highlights the graphene-gold nanoparticle (AuNP) as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS)-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer.

  16. Graphene–Gold Nanoparticles Hybrid—Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor

    Science.gov (United States)

    Khalil, Ibrahim; Julkapli, Nurhidayatullaili Muhd; Yehye, Wageeh A.; Basirun, Wan Jefrey; Bhargava, Suresh K.

    2016-01-01

    Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS) with graphene produces the graphene–AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene–Au nanocomposites. The paper highlights the graphene–gold nanoparticle (AuNP) as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS)-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer. PMID:28773528

  17. Graphene–Gold Nanoparticles Hybrid—Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor

    Directory of Open Access Journals (Sweden)

    Ibrahim Khalil

    2016-05-01

    Full Text Available Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS with graphene produces the graphene–AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene–Au nanocomposites. The paper highlights the graphene–gold nanoparticle (AuNP as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer.

  18. In-vitro cytotoxicity of biosynthesized gold nanoparticles against ...

    African Journals Online (AJOL)

    Purpose: To undertake the biosynthesis of gold nanoparticles (AuNPs) using Shorea tumbuggaia bark extract and to study their in-vitro cytotoxicity in thyroid cancer (SW579) cell lines. Methods: AuNPs were prepared by adding 10 mL of Shorea tumbuggaia extract to 5 mL of 2 × 10-3 M of chloroauric acid (HAuCl4) and ...

  19. Various methods of gold nanoparticles (GNPs conjugation to antibodies

    Directory of Open Access Journals (Sweden)

    Mir Hadi Jazayeri

    2016-07-01

    These applications require an increasingly complex level of surface decoration in order to achieve efficacy, and limit off-target toxicity. This review will discuss the chemical and physical approaches commonly utilized in relation to surface decoration and the powerful system used to indicate success of the conjugation. Finally, we review the range of recent studies about covalent and noncovalent modes for conjugation of antibodies to the particle surface that aim to advance gold nanoparticle treatments and diagnostics toward the clinic.

  20. Regioselective Localization and Tracking of Biomolecules on Single Gold Nanoparticles

    OpenAIRE

    Rajeeva, Bharath Bangalore; Hernandez, Derek S.; Wang, Mingsong; Perillo, Evan; Lin, Linhan; Scarabelli, Leonardo; Pingali, Bharadwaj; Liz?Marz?n, Luis M.; Dunn, Andrew K.; Shear, Jason B.; Zheng, Yuebing

    2015-01-01

    Selective localization of biomolecules at the hot spots of a plasmonic nanoparticle is an attractive strategy to exploit the light?matter interaction due to the high field concentration. Current approaches for hot spot targeting are time?consuming and involve prior knowledge of the hot spots. Multiphoton plasmonic lithography is employed to rapidly immobilize bovine serum albumin (BSA) hydrogel at the hot spot tips of a single gold nanotriangle (AuNT). Regioselectivity and quantity control by...

  1. Complexity of gold nanoparticle formation disclosed by dynamics study

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Jensen, Palle Skovhus; Sørensen, Karsten

    2013-01-01

    Although chemically synthesized gold nanoparticles (AuNPs) from gold salt (HAuCl4) are among the most studied nanomaterials, understanding the formation mechanisms is a challenge mainly due to limited dynamics information. A range of in situ methods with down to millisecond (ms) time resolution...... from redox potential, pH, conductivity, and turbidity of the solution enables distinct observation of reduction and nucleation/growth of AuNPs phases. The dynamics of the electrochemical potential shows that reduction of gold salt (HAuCl 4 and its hydrolyzed forms) occurs via intermediate [AuCl 2......]- to form Au atoms during the early stage of the synthesis process. pH- and conductivity-dynamics point further clearly to formation of coating layers on AuNPs and adsorbate exchange between MES and starch. © 2013 American Chemical Society....

  2. Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles.

    Science.gov (United States)

    Nirala, Narsingh R; Saxena, Preeti S; Srivastava, Anchal

    2018-02-05

    We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles

    Science.gov (United States)

    Nirala, Narsingh R.; Saxena, Preeti S.; Srivastava, Anchal

    2018-02-01

    We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2 mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19 mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100 mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel.

  4. Photoregulation of Gold Nanoparticles Stabilized in a Diacetylenic Nanocapsule

    Directory of Open Access Journals (Sweden)

    Saowalak Somjid

    2017-01-01

    Full Text Available The results of releasing a drug in a burst are unpredictable and one of the inherent drawbacks of using nanocarriers. Here, photoresponsive cationic gold nanoparticles to stabilize diacetylenic nanocapsules enabling photoregulated release of payloads are reported. The fabrication of these nanocapsules relied on an electrostatic interaction of a negatively charged diacetylenic core and a positively charged gold nanoparticle shell. Gold nanoparticles with photoresponsive ligands on their surfaces act as both hydrophobic core stabilizers and gatekeepers of the nanocapsules, while their polydiacetylene cores serve as hydrophobic drug carriers that can be tuned using UV irradiation. The morphology of nanocapsules was analyzed using TEM and dynamic light scattering. The resultant nanocapsules had a spherical shape with an average diameter of 152.9 ± 6.7 nm. Upon UV irradiation, the nanocapsules lost their integrity and an encapsulated model compound was released through diffusion. The release of a hydrophobic molecule was irradiation time dependent and thereby controllable. This light-triggered release provides an alternative strategy for controlled drug delivery.

  5. Gold nanoparticles supported on magnesium oxide for CO oxidation

    Directory of Open Access Journals (Sweden)

    Bogdanchikova Nina

    2011-01-01

    Full Text Available Abstract Au was loaded (1 wt% on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved. The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

  6. Stabilized gold nanoparticles by laser ablation in ferric chloride solutions

    Science.gov (United States)

    Nouraddini, M. I.; Ranjbar, M.; Dobson, P. J.; Farrokhpour, H.; Johnston, C.; Jurkschat, K.

    2017-12-01

    In this study, laser ablation of gold was performed in different ferric chloride solutions and water as a reference. The ferric chloride solutions included hexachloro iron(III) and aquachloro iron(III) having low and high hydrolysis degree. Transmission electron microscope (TEM) images showed spherical gold nanoparticles (GNPs) in water, particles which are strongly agglomerated with intimate contact at their interfaces in hexachloro iron(III) and individual separated particles with a halo of an iron component in aquachloro iron(III). In addition, no combination of Au and Fe was found in HAADF analysis or X-ray diffraction (XRD) patterns. In optical investigations, it was observed that gold nanoparticles made in hexachloro iron(III) solutions have localized surface plasmon resonance (LSPR) peaks broader than in the case of water that are quenched after a few hours, while ablation in the aquachloro iron(III) solution provides narrow LSPR absorption with a long-term stability. According to X-ray photoelectron spectroscopy (XPS) there are metallic Au and Fe2+ states in the drop-casted samples. By comparison of cyclic voltammetry of solutions before and after laser ablation, strong agglomeration in hexachloro iron(III) was attributed to the reducing role of iron(III) creating an unstable gold surface in the chloride solution. In aquachloro iron(III), however, the observed stability was attributed to the formation of the halo of an iron compound around the particles.

  7. Manganese oxides supported on gold nanoparticles: new findings and current controversies for the role of gold.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Hosseini, Seyedeh Maedeh; Hołyńska, Małgorzata; Tomo, Tatsuya; Allakhverdiev, Suleyman I

    2015-12-01

    We synthesized manganese oxides supported on gold nanoparticles (diameter oxide is deposited on the gold nanoparticles. The compounds were characterized by scanning electron microscopy, energy-dispersive spectrometry, high-resolution transmission electron microscopy, X-ray diffraction, UV-Vis spectroscopy, Fourier transform infrared spectroscopy, and atomic absorption spectroscopy. In the next step, the water-oxidizing activities of these compounds in the presence of cerium(IV) ammonium nitrate as a non-oxo transfer oxidant were studied. The results show that these compounds are good catalysts toward water oxidation with a turnover frequency of 1.0 ± 0.1 (mmol O2/(mol Mn·s)). A comparison with other previously reported Mn oxides and important factors influencing the water-oxidizing activities of Mn oxides is also discussed.

  8. Gold-Pluronic core-shell nanoparticles: synthesis, characterization and biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Timea; Boca, Sanda [Babes-Bolyai University, Nanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute on Bio-Nano-Sciences and Faculty of Physics (Romania); Biro, Dominic [Sapientia University, Department of Mechanical Engineering, Faculty of Technical and Human Sciences (Romania); Baldeck, Patrice [Universite Joseph Fourier and CNRS, Laboratoire Interdisciplinaire de Physique, UMR 5588, CNRS (France); Astilean, Simion, E-mail: simion.astilean@phys.ubbcluj.ro [Babes-Bolyai University, Nanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute on Bio-Nano-Sciences and Faculty of Physics (Romania)

    2013-04-15

    This study presents the synthesis of gold-Pluronic core-shell nanoparticles by a two-step method and investigates their biological impact on cancer cells, specifically nanoparticle internalization and cytotoxicity. Uniform, 9-10-nm-sized, hydrophobic gold nanoparticles were synthesized in organic phase by reducing gold salt with oleylamine, after which oleylamine-protected gold nanoparticles were phase-transferred into aqueous medium using Pluronic F127 block copolymer, resulting in gold-Pluronic core-shell nanoparticles with a mean hydrodynamic diameter of {approx}35 nm. The formation and phase-transfer of gold nanoparticles were analyzed by UV-Vis absorption spectroscopy, transmission electron microscopy, and dynamic light scattering. The obtained gold-Pluronic core-shell nanoparticles proved to be highly stable in salted solution. Cytotoxicity tests showed no modification of cellular viability in the presence of properly purified particles. Furthermore, dark-field cellular imaging demonstrated that gold-Pluronic nanoparticles were able to be efficiently uptaken by cells, being internalized through nonspecific endocytosis. The high stability, proven biocompatibility, and imaging properties of gold-Pluronic core-shell nanoparticles hold promise for relevant intracellular applications, with such a design providing the feasibility to combine all multiple functionalities in one nanoparticle for simultaneous detection and imaging.

  9. T cells enhance gold nanoparticle delivery to tumors in vivo

    Science.gov (United States)

    Kennedy, Laura C.; Bear, Adham S.; Young, Joseph K.; Lewinski, Nastassja A.; Kim, Jean; Foster, Aaron E.; Drezek, Rebekah A.

    2011-12-01

    Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production). Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation.

  10. Curcumin coated gold nanoparticles: synthesis, characterization, cytotoxicity, antioxidant activity and its comparison with citrate coated gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Elnaz Shaabani

    2017-04-01

    Full Text Available Objective(s: Biological applications of gold nanoparticles have limitations because of the toxic chemicals used in their synthesis. Curcumin can be used as reducing as well as capping agent in synthesis of GNPs to eliminate the cytotoxicity. Conjugation of curcumin to gold also helps in increasing its solubility and bioavailability. Materials and Methods: Here we report synthesis of gold nanoparticles coated with citrate and curcumin and of two different sizes via chemical routes. UV-Vis absorbance spectroscopy, Dynamic Light Scattering and Transmission Electron Microscopy were applied to study the average particle size, size stability of the samples and zeta potential. Fourier transform infrared, Raman Spectroscopy and Fluorescence Spectroscopy were applied for detection of curcumin on the surface of GNPs. The antioxidant activity was evaluated using DPPH assay and Cytotoxicity was evaluated by MTT assay.Results: Particles were synthesized of 6 and 16 nm size. The average particle size was found to be 21.7 ± 5.7 by TEM. The zeta potential on the surface of Cur-GNPs was negative and larger than 25 mV which is a sign of their high stability. The stability of these particles (with different coatings but with similar sizes at different time intervals (up to 3 months and also in different media like cell culture medium, different buffers, glucose and at different pH conditions have been investigated thoroughly. Appearance of functional groups assigned to curcumin in FTIR and SERS spectra are sign of presence of curcumin in the sample. The quenching of the fluorescence in the presence of GNPs reveals the clear indication of the capping and binding of curcumin with GNPs. Cur-GNP1 (16 nm were found to exhibit highest antioxidant activity than other gold nanoparticles. Cytotoxicity evaluation using MTT assay on L929 cell line proved curcumin coated gold nanoparticles were non-toxic up to 40 ppm.Conclusion: The results revealed that larger curcumin

  11. Coalescence and Collisions of Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Eduardo Pérez-Tijerina

    2011-01-01

    Full Text Available We study the assembling of small gold clusters subject to collisions and close contact coalescence by using molecular dynamics simulations to simulate events that occur typically in the sputtering process of synthesis. Our results support the notion that the kinetics of coalescence processes strongly determine the geometry and structure of the final particle. While impact velocities, relative orientations, and the initial shape of the interacting particles are unlikely to strictly determine the structural details of the newly formed particle, we found that high initial temperatures and/or impact velocities increase the probability of appearance of icosahedral-like structures, Wulff polyhedra are likely to be formed as a product of the interactions between nanospheres, while the appearance of fcc particles of approximately cuboctahedral shape is mainly due to the interaction between icosahedra.

  12. Synthesis and photophysical studies of phthalocyanine-gold nanoparticle conjugates.

    Science.gov (United States)

    Nombona, Nolwazi; Antunes, Edith; Litwinski, Christian; Nyokong, Tebello

    2011-11-28

    This work reports on the synthesis, characterization and photophysical studies of phthalocyanine-gold nanoparticle conjugates. The phthalocyanine complexes are: tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyanine (3), 2,9,17,23-tetrakis-[(1, 6-hexanedithiol) phthalocyaninato]zinc(II) (8) and [8,15,22-tris-(naptho)-2(amidoethanethiol) phthalocyanato] zinc(II)(10). The gold nanoparticles were characterized using transmission electron microscopy, X-ray diffraction, atomic force microscopy and UV-vis spectroscopy where the size was confirmed to be ∼5 nm. The phthalocyanine Au nanoparticle conjugates showed lower fluorescence quantum yield values with similar fluorescence lifetimes compared to the free phthalocyanines. The Au nanoparticle conjugates of 3 and 10 also showed higher triplet quantum yields of 0.69 to 0.71, respectively. A lower triplet quantum yield was obtained for the conjugate compared to free phthalocyanine for complex 8. The triplet lifetimes ranged from 70 to 92 μs for the conjugates and from 110 to 304 μs for unbound Pc complexes.

  13. Biosynthesis of Gold Nanoparticles Using Fusarium oxysporum f. sp. cubense JT1, a Plant Pathogenic Fungus

    OpenAIRE

    Thakker, Janki N.; Pranay Dalwadi; Dhandhukia, Pinakin C.

    2013-01-01

    The development of reliable processes for the synthesis of gold nanoparticles is an important aspect of current nanotechnology research. Recently, reports are published on the extracellular as well as intracellular biosynthesis of gold nanoparticles using microorganisms. However, these methods of synthesis are rather slow. In present study, rapid and extracellular synthesis of gold nanoparticles using a plant pathogenic fungus F. oxysporum f. sp. cubense JT1 (FocJT1) is reported. Incubation o...

  14. Green Synthesis of Gold and Silver Nanoparticles Using Averrhoa bilimbi Fruit Extract

    OpenAIRE

    Rimal Isaac, R. S.; Sakthivel, G.; Ch. Murthy

    2013-01-01

    We report on rapid one-step green synthesis of gold and silver nanoparticles using fruit extract of Averrhoa bilimbi Linn. UV-Vis absorption spectroscopy was used to monitor the quantitative formation of gold and silver nanoparticles. The characteristics of the obtained gold and silver nanoparticles were studied using UV-Vis absorption spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy-dispersive spectroscopy (EDX). UV/Vis spe...

  15. Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, Mark F [ORNL; Woodward, Jonathan [ORNL; Boll, Rose Ann [ORNL; Wall, Jonathan [University of Tennessee, Knoxville (UTK); Rondinone, Adam Justin [ORNL; Kennel, Steve J [ORNL; Mirzadeh, Saed [ORNL; Robertson, David J. [University of Missouri

    2013-01-01

    Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo generators such as 225Ac, which emits four particles in its decay chain, can significantly amplify the radiation dose delivered to the target site. However, renal dose from unbound 213Bi escaping during the decay process limits the dose of 225Ac that can be administered. Traditional chelating moieties are unable to sequester the radioactive daughters because of the high recoil energy from alpha particle emission. To counter this, we demonstrate that an engineered multilayered nanoparticle-antibody conjugate can both deliver radiation and contain the decay daughters of the in vivo -generator 225Ac while targeting biologically relevant receptors. These multi-shell nanoparticles combine the radiation resistance of crystalline lanthanide phosphate to encapsulate and contain 225Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established surface chemistry of gold for attachment of nanoparticles to targeting antibodies.

  16. Synthesis and characterization of gold nanoparticles using Ficus religiosa extract

    Directory of Open Access Journals (Sweden)

    Kirtee Wani

    2013-03-01

    Full Text Available We report a cost effective and eco-friendly biosynthesis of gold nanoparticles (F-AuNPs using aqueous extract of Ficus religiosa as the reducing and stabilizing agent. These nanoparticles were characterized by various techniques such as UV-Vis, XRD, TEM and FTIR. The characteristic surface plasmon peak was observed at 540 nm while XRD analysis suggested it to be a face-centered cubic (fcc structure with peaks at 38.06, 44.46, 64.75 and 77.56. FTIR studies indicated the capping of the nanoparticles with polyphenols, amines and carboxylates present in the extract of Ficus religiosa whereas TEM analysis showed spherical morphology with other shapes such as triangles and hexagons. The F-AuNPs were found to be non-toxic to HEK 293 cells, thereby suggesting their potential application in the field of nanobiotechnology.

  17. Gold Nanoparticles Decorated with Mannose-6-phosphate Analogues

    Directory of Open Access Journals (Sweden)

    Stéphanie Combemale

    2014-01-01

    Full Text Available Herein, the preparation of neoglycoconjugates bearing mannose-6-phosphate analogues is described by: (a synthesis of a cyclic sulfate precursor to access the carbohydrate head-group by nucleophilic displacement with an appropriate nucleophile; (b introduction of spacers on the mannose-6-phosphate analogues via Huisgen’s cycloaddition, the Julia reaction, or the thiol-ene reaction under ultrasound activation. With the resulting compounds in hand, gold nanoparticles could be functionalized with various carbohydrate derivatives (glycoconjugates and then tested for angiogenic activity. It was observed that the length and flexibility of the spacer separating the sugar analogue from the nanoparticle have little influence on the biological response. One particular nanoparticle system substantially inhibits blood vessel growth in contrast to activation by the corresponding monomeric glycoconjugate, thereby demonstrating the importance of multivalency in angiogenic activity.

  18. Targeted cancer theranostics using alpha-tocopheryl succinate-conjugated multifunctional dendrimer-entrapped gold nanoparticles.

    Science.gov (United States)

    Zhu, Jingyi; Zheng, Linfeng; Wen, Shihui; Tang, Yueqin; Shen, Mingwu; Zhang, Guixiang; Shi, Xiangyang

    2014-08-01

    Development of multifunctional theranostic nanoplatforms for targeted cancer imaging and therapy still remains a great challenge. Herein, we report the use of multifunctional dendrimer-entrapped gold nanoparticles (Au DENPs) covalently linked with α-tocopheryl succinate (α-TOS) as a platform for targeted cancer computed tomography (CT) imaging and therapy. In this study, amine-terminated poly(amidoamine) dendrimers of generation 5 (G5.NH2) conjugated with fluorescein isothiocyanate (FI), polyethylene glycol (PEG)-modified α-TOS, and PEGylated folic acid (FA) were used as templates to synthesize Au DENPs, followed by acetylation of the remaining dendrimer terminal amines. The formed multifunctional Au DENPs were characterized via different techniques. We show that the Au DENPs conjugated with approximately 9.8 α-TOS molecules per dendrimer and with an Au core size of 3.3 nm are water-dispersible, and stable under different pH and temperature conditions and in different aqueous media. The FA modification onto the Au DENPs enables efficient targeting of the particles to cancer cells overexpressing FA receptors (FAR), and effective targeted CT imaging of the cancer cells in vitro and the xenografted tumor model in vivo. Likewise, the covalent conjugation of α-TOS does not compromise its therapeutic activity, instead significantly improves its water solubility. Importantly, thanks to the role of FA-directed targeting, the formed multifunctional Au DENPs are able to exert the specific therapeutic efficacy of α-TOS to the FAR-overexpressing cancer cells in vitro and the xenografted tumor model in vivo. The developed multifunctional Au DENPs may hold a great promise to be used as a unique theranostic nanoplatform for targeted CT imaging and therapy of different types of cancer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Water-soluble plasmonic nanosensors with synthetic receptors for label-free detection of folic acid.

    Science.gov (United States)

    Ahmad, Randa; Félidj, Nordin; Boubekeur-Lecaque, Leïla; Lau-Truong, Stéphanie; Gam-Derouich, Sarra; Decorse, Philippe; Lamouri, Aazdine; Mangeney, Claire

    2015-06-14

    We describe an original approach to graft molecularly imprinted polymers around gold nanorods by combining the diazonium salt chemistry and the iniferter method. This chemical strategy enables fine control of the imprinting process at the nanometer scale and provides water-soluble plasmonic nanosensors.

  20. Electron and photon emissions from gold nanoparticles irradiated by X-ray photons

    Energy Technology Data Exchange (ETDEWEB)

    Casta, R., E-mail: castaromain@gmail.com, E-mail: romain.casta@irsamc.ups-tlse.fr; Champeaux, J.-P.; Moretto-Capelle, P.; Sence, M.; Cafarelli, P. [Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, CNRS, UMR 5589 (France)

    2015-01-15

    In this paper, we develop a totally new probabilistic model for the electron and photon emission of gold nanoparticles irradiated by X-ray photons. This model allows direct applications to recent researches about the radiotherapy enhancement by gold nanoparticles in the context of cancer treatment. Our model uses, in a complete original way, simulated Auger cascade and stopping power to compute electron emission spectra, photon emission spectra and released energy inside the material of gold nanoparticles. It allows us to present new results about the electron and photon emission of gold nanoparticle irradiated by hard X-rays.

  1. Crystal Growth of Thiol-Stabilized Gold Nanoparticles by Heat-Induced Coalescence

    Directory of Open Access Journals (Sweden)

    Moon SookYoung

    2010-01-01

    Full Text Available Abstract A monolayer of dodecanethiol-stabilized gold nanoparticles changed into two-dimensional and three-dimensional self-organized structures by annealing at 323 K. Subsequent crystal growth of gold nanoparticles occurred. Thiol molecules, although chemisorbed, form relatively unstable bonds with the gold surface; a few thiols desorbed from the surface and oxidized to disulfides at 323 K, because the interaction energy between thiol macromolecules is larger than that between a thiol and a nanoparticle. The gold nanoparticles approached each other and grew into large single or twinned crystals because of the van der Waals attraction and the heat generated by the exothermic formation of disulfides.

  2. Synthesis of gold and silver nanoparticles using leaf extract of Perilla frutescens--a biogenic approach.

    Science.gov (United States)

    Basavegowda, Nagaraj; Lee, Yong Rok

    2014-06-01

    The present investigation demonstrates a rapid biogenic approach for the synthesis of gold and silver nanoparticles using biologically active and medicinal important Perilla frutescens leaf extract as a reducing and stabilizing agent under ambient conditions. Gold and silver nanoparticles were first synthesized from Perilla frutescens leaf extract which was used as a vegetable and in traditional medicines for a long time in Korea, Japan, and China. The nanoparticles obtained were characterized by UV-vis spectroscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Surface plasmon resonance spectra of gold and silver nanoparticles were obtained at 540 and 430 nm and triangular and spherical shape respectively. TEM studies showed that the particle sizes of gold and silver nanoparticles ranges -50 nm and -40 nm respectively. X-ray diffraction studies confirm that the biosynthesized nanoparticles were crystalline gold and silver. Fourier transform infra-red spectroscopy revealed that biomolecules were involved in the synthesis and capping of the nanoparticles produced. XRD and EDX confirmed the formation of gold and silver nanoparticles. This is a simple, efficient and rapid method to synthesize gold and silver nanoparticles at room temperature without use of toxic chemicals. Obtained gold and silver nanoparticles can be used in various biomedical and biotechnological applications.

  3. Heat Profiling of Three-Dimensionally Optically Trapped Gold Nanoparticles using Vesicle Cargo Release

    DEFF Research Database (Denmark)

    Kyrsting, Anders; Bendix, Pól Martin; Stamou, Dimitrios

    2011-01-01

    Irradiated metallic nanoparticles hold great promise as heat transducers in photothermal applications such as drug delivery assays or photothermal therapy. We quantify the temperature increase of individual gold nanoparticles trapped in three dimensions near lipid vesicles exhibiting temperature ...

  4. Synthesis and bioconjugation of gold nanoparticles as potential molecular probes for light-based imaging techniques

    NARCIS (Netherlands)

    Rayavarapu, Raja Gopal; Petersen, Wilma; Ungureanu, Constantin; Post, Janine N.; van Leeuwen, Ton G.; Manohar, Srirang

    2007-01-01

    We have synthesized and characterized gold nanoparticles (spheres and rods) with optical extinction bands within the "optical imaging window." The intense plasmon resonant driven absorption and scattering peaks of these nanoparticles make them suitable as contrast agents for optical imaging

  5. Investigating the toxicity, uptake, nanoparticle formation and genetic response of plants to gold.

    Directory of Open Access Journals (Sweden)

    Andrew F Taylor

    Full Text Available We have studied the physiological and genetic responses of Arabidopsis thaliana L. (Arabidopsis to gold. The root lengths of Arabidopsis seedlings grown on nutrient agar plates containing 100 mg/L gold were reduced by 75%. Oxidized gold was subsequently found in roots and shoots of these plants, but gold nanoparticles (reduced gold were only observed in the root tissues. We used a microarray-based study to monitor the expression of candidate genes involved in metal uptake and transport in Arabidopsis upon gold exposure. There was up-regulation of genes involved in plant stress response such as glutathione transferases, cytochromes P450, glucosyl transferases and peroxidases. In parallel, our data show the significant down-regulation of a discreet number of genes encoding proteins involved in the transport of copper, cadmium, iron and nickel ions, along with aquaporins, which bind to gold. We used Medicago sativa L. (alfalfa to study nanoparticle uptake from hydroponic culture using ionic gold as a non-nanoparticle control and concluded that nanoparticles between 5 and 100 nm in diameter are not directly accumulated by plants. Gold nanoparticles were only observed in plants exposed to ionic gold in solution. Together, we believe our results imply that gold is taken up by the plant predominantly as an ionic form, and that plants respond to gold exposure by up-regulating genes for plant stress and down-regulating specific metal transporters to reduce gold uptake.

  6. Investigating the Toxicity, Uptake, Nanoparticle Formation and Genetic Response of Plants to Gold

    Science.gov (United States)

    Taylor, Andrew F.; Rylott, Elizabeth L.; Anderson, Christopher W. N.; Bruce, Neil C.

    2014-01-01

    We have studied the physiological and genetic responses of Arabidopsis thaliana L. (Arabidopsis) to gold. The root lengths of Arabidopsis seedlings grown on nutrient agar plates containing 100 mg/L gold were reduced by 75%. Oxidized gold was subsequently found in roots and shoots of these plants, but gold nanoparticles (reduced gold) were only observed in the root tissues. We used a microarray-based study to monitor the expression of candidate genes involved in metal uptake and transport in Arabidopsis upon gold exposure. There was up-regulation of genes involved in plant stress response such as glutathione transferases, cytochromes P450, glucosyl transferases and peroxidases. In parallel, our data show the significant down-regulation of a discreet number of genes encoding proteins involved in the transport of copper, cadmium, iron and nickel ions, along with aquaporins, which bind to gold. We used Medicago sativa L. (alfalfa) to study nanoparticle uptake from hydroponic culture using ionic gold as a non-nanoparticle control and concluded that nanoparticles between 5 and 100 nm in diameter are not directly accumulated by plants. Gold nanoparticles were only observed in plants exposed to ionic gold in solution. Together, we believe our results imply that gold is taken up by the plant predominantly as an ionic form, and that plants respond to gold exposure by up-regulating genes for plant stress and down-regulating specific metal transporters to reduce gold uptake. PMID:24736522

  7. Biosynthesis of gold nanoparticles using streptomyces fulvissimus isolate

    Directory of Open Access Journals (Sweden)

    Meysam Soltani Nejad

    2015-04-01

    Full Text Available Objective(s: In recent years, the biosynthesis of gold nanoparticles has been the focus of interest because of their emerging application in a number of areas such as biomedicine. In the present study we report the extracellular biosynthesis of gold nanoparticles (AuNPs by using a positive bacterium named Streptomyces fulvissimus isolate U from rice fields of Guilan Province, Iran. Materials and Methods: From over 20 Streptomyces isolates collected, isolate U showed high AuNPs biosynthesis activity. To determine its taxonomical identity, its morphology was characterized by scanning electron microscope and partial molecular analysis performed by PCR. In this regard, 16S rDNA of isolate U was amplified using universal bacterial primers FD1 and RP2. The PCR products were purified and sequenced. Sequence analysis of 16S rDNA was then conducted using NCBI BLAST method. In biosynthesis of AuNPs by this bacterium, the biomass of bacterium exposed to the HAuCl4 solution. Results: The nanoparticles obtained were characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM and Energy dispersive X-ray (EDX spectroscopy and X-ray diffraction spectroscopy (XRD analyses. Our results indicated that Streptomyces fulvissimus isolateU bio-synthesizes extracellular AuNPs in the range of 20-50 nm. Conclusions: This technique of green synthesis of AuNPs by a microbial source may become a promising method because of its environmental safety. Its optimization may make it a potential procedure for industrial production of gold nanoparticles.

  8. Radiolabeled theranostics: magnetic and gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Saeideh Same

    2016-09-01

    Methods: In this study, we review the most recent works on the improvement of various techniques for development of radiolabeled magnetic and gold nanoprobes, and discuss the methods for targeted imaging and therapies. Results: The receptor-specific radiopharmaceuticals have been developed to localized radiotherapy in disease sites. Application of advanced multimodal imaging methods and related modality imaging agents labeled with various radioisotopes (e.g., 125I, 111In, 64Cu, 68Ga, 99mTc and MNPs/GNPs have significant effects on treatment and prognosis of cancer therapy. In addition, the surface modification with biocompatible polymer such as polyethylene glycol (PEG have resulted in development of stealth NPs that can evade the opsonization and immune clearance. These long-circulating agents can be decorated with homing agents as well as radioisotopes for targeted imaging and therapy purposes. Conclusion: The modified MNPs or GNPs have wide applications in concurrent diagnosis and therapy of various malignancies. Once armed with radioisotopes, these nanosystems (NSs can be exploited for combined multimodality imaging with photothermal/photodynamic therapy while delivering the loaded drugs or genes to the targeted cells/tissues. These NSs will be a game changer in combating various cancers.

  9. An in-vitro studies on green synthesis of gold nanoparticles against pathogens and cancer cells

    Directory of Open Access Journals (Sweden)

    V. Ramesh

    2015-11-01

    Full Text Available Nanotechnology is a most promising field for generating new applications in medicine. It is imperative to integrate nanoscience and medicine. The present investigation is highly warranted to through more light upon the gold nanoparticles reduced from gold salt through the active principle of medicinal plant. The special emphasis of investigation is the active principle along with gold nanoparticles against for cancer cells. The 70 - 90 nm sized particles were synthesized by using Diospyros ferrea and this confirmed by SEM. These gold nanoparticles showed a characteristic absorption peak at 540 nm in UV spectra. The possibility of protein as a stabilizing material in gold nanoparticles is revealed by FTIR analysis. Remarkably, as a result of wide screening on the application of newly synthesized gold nanoparticles their anticancer potential has been discovered using MTT assay. The antimicrobial activity of AuNPs showed effective against bacteria than the fungal strains.

  10. Biotin Decorated Gold Nanoparticles for Targeted Delivery of a Smart-Linked Anticancer Active Copper Complex: In Vitro and In Vivo Studies.

    Science.gov (United States)

    Pramanik, Anup K; Siddikuzzaman; Palanimuthu, Duraippandi; Somasundaram, Kumaravel; Samuelson, Ashoka G

    2016-12-21

    The synthesis and anticancer activity of a copper(II) diacetyl-bis(N4-methylthiosemicarbazone) complex and its nanoconjugates are reported. The copper(II) complex is connected to a carboxylic acid group through a cleavable disulfide link to enable smart delivery. The copper complex is tethered to highly water-soluble 20 nm gold nanoparticles (AuNPs), stabilized by amine terminated lipoic acid-polyethylene glycol (PEG). The gold nanoparticle carrier was further decorated with biotin to achieve targeted action. The copper complex and the conjugates with and without biotin, were tested against HeLa and HaCaT cells. They show very good anticancer activity against HeLa cells, a cell line derived from cervical cancer and are less active against HaCaT cells. Slow and sustained release of the complex from conjugates is demonstrated through cleavage of disulfide linker in the presence of glutathione (GSH), a reducing agent intrinsically present in high concentrations within cancer cells. Biotin appended conjugates do not show greater activity than conjugates without biotin against HeLa cells. This is consistent with drug uptake studies, which suggests similar uptake profiles for both conjugates in vitro. However, in vivo studies using a HeLa cell xenograft tumor model shows 3.8-fold reduction in tumor volume for the biotin conjugated nanoparticle compared to the control whereas the conjugate without biotin shows only 2.3-fold reduction in the tumor volume suggesting significant targeting.

  11. Gold-Speckled Multimodal Nanoparticles for Noninvasive Bioimaging

    Science.gov (United States)

    2008-01-01

    In this report the synthesis, characterization, and functional evaluation of a multimodal nanoparticulate contrast agent for noninvasive imaging through both magnetic resonance imaging (MRI) and photoacoustic tomography (PAT) is presented. The nanoparticles described herein enable high resolution and highly sensitive three-dimensional diagnostic imaging through the synergistic coupling of MRI and PAT capabilities. Gadolinium (Gd)-doped gold-speckled silica (GSS) nanoparticles, ranging from 50 to 200 nm, have been prepared in a simple one-pot synthesis using nonionic microemulsions. The photoacoustic signal is generated from a nonuniform, discontinuous gold nanodomains speckled across the silica surface, whereas the MR contrast is provided through Gd incorporated in the silica matrix. The presence of a discontinuous speckled surface, as opposed to a continuous gold shell, allows sufficient bulk water exchange with the Gd ions to generate a strong MR contrast. The dual imaging capabilities of the particles have been demonstrated through in silicio and in vitro methods. The described particles also have the capacity for therapeutic applications including the thermal ablation of tumors through the absorption of irradiated light. PMID:19466201

  12. Facile green synthesis of variable metallic gold nanoparticle using Padina gymnospora, a brown marine macroalga

    Science.gov (United States)

    Singh, M.; Kalaivani, R.; Manikandan, S.; Sangeetha, N.; Kumaraguru, A. K.

    2013-04-01

    The process of development of reliable and eco-friendly metallic nanoparticles is an important step in the field of nanotechnology. To achieve this, use of natural sources like biological systems becomes essential. In the present work, extracellular biosynthesis of gold nanoparticles using Padina gymnospora has been attempted and achieved rapid formation of gold nanoparticles in a short duration. The UV-vis spectrum of the aqueous medium containing gold ion showed peak at 527 nm corresponding to the plasmon absorbance of gold nanoparticles. Scanning electron microscopy showed the formation of well-dispersed gold nanoparticles. FTIR spectra of brown alga confirmed that hydroxyl groups present in the algal polysaccharides were involved in the gold bioreduction. AFM analysis showed the results of particle sizes (53-67 nm) and average height of the particle roughness (60.0 nm). X-ray diffraction (XRD) spectrum of the gold nanoparticles exhibited Bragg reflections corresponding to gold nanoparticles. This environment-friendly method of biological gold nanoparticle synthesis can be applied potentially in various products that directly come in contact with the human body, such as cosmetics, and foods and consumer goods, besides medical applications.

  13. Oxidative stress and toxicity of gold nanoparticles in Mytilus edulis

    Energy Technology Data Exchange (ETDEWEB)

    Tedesco, Sara [Environmental Research Institute of University College Cork, Cork (Ireland); Doyle, Hugh [Tyndall National Institute, Cork (Ireland); Blasco, Julian [Consejo Superior de Investigaciones Cientificas (CSIC), Marine Science Institute of Andalusia, Cadiz (Spain); Redmond, Gareth [Tyndall National Institute, Cork (Ireland); Sheehan, David, E-mail: d.sheehan@ucc.ie [Environmental Research Institute of University College Cork, Cork (Ireland)

    2010-10-15

    Gold nanoparticles (AuNP) have potential applications in drug delivery, cancer diagnosis and therapy, food industry and environment remediation. However, little is known about their potential toxicity or fate in the environment. Mytilus edulis was exposed in tanks to750 ppb AuNP (average diameter 5.3 {+-} 1 nm) for 24 h to study in vivo biological effects of nanoparticles. Traditional biomarkers and an affinity procedure selective for thiol-containing proteins followed by two-dimensional electrophoresis (2DE) separations were used to study toxicity and oxidative stress responses. Results were compared to those obtained for treatment with cadmium chloride, a well known pro-oxidant. M. edulis mainly accumulated AuNP in digestive gland which also showed higher lipid peroxidation. One-dimensional SDS/PAGE (1DE) and 2DE analysis of digestive gland samples revealed decreased thiol-containing proteins for AuNP. Lysosomal membrane stability measured in haemolymph gave lower values for neutral red retention time (NRRT) in both treatments but was greater in AuNP. Oxidative stress occurred within 24 h of AuNP exposure in M. edulis. Previously we showed that larger diameter AuNP caused modest effects, indicating that nanoparticle size is a key factor in biological responses to nanoparticles. This study suggests that M. edulis is a suitable model animal for environmental toxicology studies of nanoparticles.

  14. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moreira dos Santos, Margarida, E-mail: margarida.santos@fct.unl.pt; Queiroz, Margarida Joao; Baptista, Pedro V. [Universidade Nova de Lisboa, CIGMH, Departamento Ciencias da Vida, Faculdade de Ciencias e Tecnologia (Portugal)

    2012-05-15

    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 {+-} 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a {beta}-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle-antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  15. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    Science.gov (United States)

    dos Santos, Margarida Moreira; Queiroz, Margarida João; Baptista, Pedro V.

    2012-05-01

    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 ± 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a β-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle-antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  16. Synthesis of Gold Nanoparticles Using Whole Cells of Geotrichum candidum

    Directory of Open Access Journals (Sweden)

    Amit Kumar Mittal

    2013-01-01

    Full Text Available The synthesis of nanoparticles with desired size and shape is an important area of research in nanotechnology. Use of biological system is an alternative approach to chemical and physical procedures for the synthesis of metal nanoparticles. An efficient environment-friendly approach for the biosynthesis of rapid and stable Gold nanoparticles (AuNPs using whole cells of Geotrichum candidum is discussed in this paper. The enzymes/proteins present in the microorganism might be responsible for the reduction of metal salts to nanoparticles. Various reaction parameters such as culture age, temperature, pH, metal salt, and cell mass concentrations were optimized. The AuNPs were characterized by UV-visible spectroscopy, dynamic light scattering (DLS, energy dispersive spectroscopy (EDS, scanning electron microscope (SEM, and Fourier transform infrared spectroscopy (FTIR. Nanoparticles were isolated by sonicating the whole cells after treatment with Tween 80. The whole cell mediated process showed the simplistic, feasible, easy to scale up, and low-cost approach for the synthesis of AuNPs.

  17. Biosynthesis and characterization of gold nanoparticles using extracts of tamarindus indica L leaves

    Science.gov (United States)

    Correa, S. N.; Naranjo, A. M.; Herrera, A. P.

    2016-02-01

    This study reports the biosynthesis of gold nanoparticles using an extract of Tamarindus indica L. leaves. Phenols, ketones and carboxyls were present in the leaves of T. indica. These organic compounds that allowed the synthesis of nanoparticles were identified by gas chromatography coupled to mass spectrometry (GC/MS) and High Pressure Liquid Chromatographic (HPLC). Synthesis of gold nanoparticles was performed with the extract of T. indica leaves and an Au+3 aqueous solutions (HAuCl4) at room temperature with one hour of reaction time. Characterization of gold nanoparticles was performed by UV visible spectroscopy, scanning electron microscopy (SEM) and EDX. The results indicated the formation of gold nanoparticles with a wavelength of 576nm and an average size of 52±5nm. The EDX technique confirmed the presence of gold nanoparticles with 12.88% in solution.

  18. Gold nanoparticles with patterned surface monolayers for nanomedicine: current perspectives.

    Science.gov (United States)

    Pengo, Paolo; Şologan, Maria; Pasquato, Lucia; Guida, Filomena; Pacor, Sabrina; Tossi, Alessandro; Stellacci, Francesco; Marson, Domenico; Boccardo, Silvia; Pricl, Sabrina; Posocco, Paola

    2017-12-01

    Molecular self-assembly is a topic attracting intense scientific interest. Various strategies have been developed for construction of molecular aggregates with rationally designed properties, geometries, and dimensions that promise to provide solutions to both theoretical and practical problems in areas such as drug delivery, medical diagnostics, and biosensors, to name but a few. In this respect, gold nanoparticles covered with self-assembled monolayers presenting nanoscale surface patterns-typically patched, striped or Janus-like domains-represent an emerging field. These systems are particularly intriguing for use in bio-nanotechnology applications, as presence of such monolayers with three-dimensional (3D) morphology provides nanoparticles with surface-dependent properties that, in turn, affect their biological behavior. Comprehensive understanding of the physicochemical interactions occurring at the interface between these versatile nanomaterials and biological systems is therefore crucial to fully exploit their potential. This review aims to explore the current state of development of such patterned, self-assembled monolayer-protected gold nanoparticles, through step-by-step analysis of their conceptual design, synthetic procedures, predicted and determined surface characteristics, interactions with and performance in biological environments, and experimental and computational methods currently employed for their investigation.

  19. Unique Gold Nanoparticle Aggregates as a Highly Active SERS Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Schwartzberg, A M; Grant, C D; Wolcott, A; Talley, C E; Huser, T R; Bogomolni, R; Zhang, J Z

    2004-04-06

    A unique gold nanoparticle aggregate (GNA) system has been shown to be an excellent substrate for surface-enhanced Raman scattering (SERS) applications. Rhodamine 6G (R6G), a common molecule used for testing SERS activity on silver, but generally difficult to detect on gold substrates, has been found to readily bind to the GNA and exhibit strong SERS activity due to the unique surface chemistry afforded by sulfur species on the surface. This GNA system has yielded a large SERS enhancement of 10{sup 7}-10{sup 9} in bulk solution for R6G, on par with or greater than any previously reported gold SERS substrate. SERS activity has also been successfully demonstrated for several biological molecules including adenine, L-cysteine, L-lysine, and L-histidine for the first time on a gold SERS substrate, showing the potential of this GNA as a convenient and powerful SERS substrate for biomolecular detection. In addition, SERS spectrum of R6G on single aggregates has been measured. We have shown that the special surface properties of the GNA, in conjunction with strong near IR absorption, make it useful for SERS analysis of a wide variety of molecules.

  20. Highly stable noble metal nanoparticles dispersible in biocompatible solvents: synthesis of cationic phosphonium gold nanoparticles in water and DMSO.

    Science.gov (United States)

    Ju-Nam, Yon; Abdussalam-Mohammed, Wanisa; Ojeda, Jesus J

    2016-01-01

    In this work, we report the synthesis of novel cationic phosphonium gold nanoparticles dispersible in water and dimethyl sulfoxide (DMSO) for their potential use in biomedical applications. All the cationic-functionalising ligands currently reported in the literature are ammonium-based species. Here, the synthesis and characterisation of an alternative system, based on phosphonioalkylthiosulfate zwitterions and phosphonioalkylthioacetate were carried out. We have also demonstrated that our phosphonioalkylthiosulfate zwitterions readily disproportionate into phosphonioalkylthiolates in situ during the synthesis of gold nanoparticles produced by the borohydride reduction of gold(III) salts. The synthesis of the cationic gold nanoparticles using these phosphonium ligands was carried out in water and DMSO. UV-visible spectroscopic and TEM studies have shown that the phosphonioalkylthiolates bind to the surface of gold nanoparticles which are typically around 10 nm in diameter. The resulting cationic-functionalised gold nanoparticles are dispersible in aqueous media and in DMSO, which is the only organic solvent approved by the U.S. Food and Drug Administration (FDA) for drug carrier tests. This indicates their potential future use in biological applications. This work shows the synthesis of a new family of phosphonium-based ligands, which behave as cationic masked thiolate ligands in the functionalisation of gold nanoparticles. These highly stable colloidal cationic phosphonium gold nanoparticles dispersed in water and DMSO can offer a great opportunity for the design of novel biorecognition and drug delivery systems.

  1. Controlling the morphology of multi-branched gold nanoparticles

    Science.gov (United States)

    Ahmed, Waqqar; Kooij, E. Stefan; van Silfhout, Arend; Poelsema, Bene

    2010-03-01

    We demonstrate a simple and versatile way to achieve high yield synthesis of shape- and size-controlled multi-branched gold nanoparticles (MBNPs). Control over the shape of the MBNPs was achieved by varying the ratio of gold to the mild reducing agent ascorbic acid, using a seed-mediated growth approach. Higher ascorbate concentrations resulted in the smoothing of branches, leading to the yield of relatively more isotropic particles. Furthermore, we found that using much higher silver concentrations in the growth solution resulted in the formation of rod-shaped micro-features together with MBNPs; we postulate them to be cetyltrimethyl ammonium silver bromide crystals. The as-prepared MBNPs show interesting tunable optical properties that are strongly influenced by the particle shape. The results are discussed in terms of plasmon coupling between the core and branches of the MBNPs.

  2. Antibody immobilized cysteamine functionalized-gold nanoparticles for aflatoxin detection

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Aditya; Matharu, Zimple; Sumana, G.; Solanki, Pratima R. [Department of Science and Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, Materials Physics and Engineering Division, National Physical Laboratory (Council of Scientific and Industrial Research), Dr. K. S. Krishnan Marg, New Delhi-110012 (India); Kim, C.G. [Centre for NanoBioEngineering and Spintronics, Chungnam National University, Daejeon, 305-764 (Korea, Republic of); Malhotra, B.D., E-mail: bansi.malhotra@gmail.co [Department of Science and Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, Materials Physics and Engineering Division, National Physical Laboratory (Council of Scientific and Industrial Research), Dr. K. S. Krishnan Marg, New Delhi-110012 (India); Centre for NanoBioEngineering and Spintronics, Chungnam National University, Daejeon, 305-764 (Korea, Republic of)

    2010-11-30

    Aflatoxin B{sub 1} antibody (aAFB{sub 1}) covalently attached to cysteamine functionalized-gold nanoparticles (C-AuNP) has been immobilized onto 4-mercaptobenzoic acid (MBA) based self assembled monolayer (SAM) on gold electrode (MBA/Au), for the fabrication of BSA/aAFB{sub 1}-C-AuNP/MBA/Au immunoelectrode. This immunoelectrode has been characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and electrochemical characterization techniques. The electrochemical response studies reveal that the BSA/aAFB{sub 1}-C-AuNP/MBA/Au immunoelectrode can be used to detect AFB{sub 1} in the range of 10-100 ng dL{sup -1} and has sensitivity as 0.45 {mu}A ng{sup -1} dL, limit of detection as 17.90 ng dL{sup -1} and a response time of 60 s.

  3. Preparation of glucose sensors using gold nanoparticles modified diamond electrode

    Science.gov (United States)

    Fachrurrazie; Ivandini, T. A.; Wibowo, W.

    2017-04-01

    A glucose sensor was successfully developed by immobilizing glucose oxidase (GOx) at boron-doped diamond (BDD) electrodes. Prior to GOx immobilization, the BDD was modified with gold nanoparticles (AuNPs). To immobilize AuNPs, the gold surface was modified to nitrogen termination. The characterization of the electrode surface was performed using an X-ray photoelectron spectroscopy and a scanning electron microscope, while the electrochemical properties of the enzyme electrode were characterized using cyclic voltammetry. Cyclic voltammograms of the prepared electrode for D-glucose in phosphate buffer solution pH 7 showed a new reduction peak at +0.16 V. The currents of the peak were linear in the concentration range of 0.1 M to 0.9 M, indicated that the GOx-AuNP-BDD can be applied for electrochemical glucose detection.

  4. Biosynthesis of gold nanoparticles by Pseudomonas veronii AS41G inhabiting Annona squamosa L.

    Science.gov (United States)

    Baker, Syed; Satish, Sreedharamurthy

    2015-11-05

    Biogenic principles to nanotechnology have generated tremendous attention in recent past owing eco friendly benign process for synthesis of nanoparticles. Present investigation reports extracellular synthesis of gold nanoparticles using cell free supernatant of Pseudomonas veronii AS 41G, a novel endophyte isolated from Annona squamosa L. Gold nanoparticles formation was confirmed with UV-Visible spectrophotometer. FTIR analysis predicted various functional groups responsible for reduction of metal salts and stabilization of gold nanoparticles. Nanoparticles were crystalline in nature as shown in XRD pattern. TEM analysis revealed morphological characteristics of nanoparticles with different size. Thus the present study attributes for facile process for synthesis of gold nanoparticles as an alternative for conventional methods. The study also highlights the new role of novel bacterium Pseudomonas veronii AS41G which will be very valuable as a record for the researchers working on it. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Gold Nanoparticles and Their Alternatives for Radiation Therapy Enhancement

    Directory of Open Access Journals (Sweden)

    Daniel R. Cooper

    2014-10-01

    Full Text Available Radiation therapy is one of the most commonly used treatments for cancer. The dose of delivered ionizing radiation can be amplified by the presence of high-Z materials via an enhancement of the photoelectric effect; the most widely studied material is gold (atomic number 79. However, a large amount is needed to obtain a significant dose enhancement, presenting a challenge for delivery. In order to make this technique of broader applicability, the gold must be targeted, or alternative formulations developed that do not rely solely on the photoelectric effect. One possible approach is to excite scintillating nanoparticles with ionizing radiation, and then exploit energy transfer between these particles and attached dyes in a manner analogous to photodynamic therapy. Doped rare-earth halides and semiconductor quantum dots have been investigated for this purpose. However, although the spectrum of emitted light after radiation excitation is usually similar to that seen with light excitation, the yield is not. Measurement of scintillation yields is challenging, and in many cases has been done only for bulk materials, with little understanding of how the principles translate to the nanoscale. Another alternative is to use local heating using gold or iron, followed by application of ionizing radiation. Hyperthermia pre-sensitizes the tumors, leading to an improved response. Another approach is to use chemotherapeutic drugs that can radiosensitize tumors. Drugs may be attached to high-Z nanoparticles or encapsulated. This article discusses each of these techniques, giving an overview of the current state of nanoparticle-assisted radiation therapy and future directions.

  6. Two-dimensional hyper-branched gold nanoparticles synthesized on a two-dimensional oil/water interface

    National Research Council Canada - National Science Library

    Shin, Yonghee; Lee, Chiwon; Yang, Myung-Seok; Jeong, Sunil; Kim, Dongchul; Kang, Taewook

    2014-01-01

    Two-dimensional (2D) gold nanoparticles can possess novel physical and chemical properties, which will greatly expand the utility of gold nanoparticles in a wide variety of applications ranging from catalysis to biomedicine...

  7. Biochemical synthesis of water soluble conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Ferdinando F., E-mail: Ferdinando-Bruno@uml.edu [US Army Natick Soldier Research, Development and Engineering Center, Natick, MA 01760 (United States); Bernabei, Manuele [ITAF, Test Flight Centre, Chemistry Dept. Pratica di Mare AFB, 00071 Pomezia (Rome), Italy (UE) (Italy)

    2016-05-18

    An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

  8. Optical Properties of Gold Nanoparticle Assemblies on a Glass Surface

    Science.gov (United States)

    Stetsenko, M. O.; Rudenko, S. P.; Maksimenko, L. S.; Serdega, B. K.; Pluchery, O.; Snegir, S. V.

    2017-05-01

    The assemblies of cross-linked gold nanoparticles (AuNP) attract lot of scientific attention due to feasible perspectives of their use for development of scaled contact electrodes. Here, we developed and tested method of solid-state formation of dimers created from small AuNP ( 18 nm) cross-linked with 1.9-nonadithiol (NDT) molecules. The morphology of created coating of a glass surface and its optical-polarization properties have been studied in detail by combination of scanning electron microscopy, atomic force microscopy, UV-visible spectroscopy, and modulation-polarization spectroscopy.

  9. Gold nanorods-silica Janus nanoparticles for theranostics

    Science.gov (United States)

    Wang, Ying-Shuai; Shao, Dan; Zhang, Lu; Zhang, Xu-Lin; Li, Jing; Feng, Jing; Xia, Hong; Huo, Qi-Sheng; Dong, Wen-Fei; Sun, Hong-Bo

    2015-04-01

    A multi-functional gold nanorods-mesoporous silica Janus nanoparticles (NPs) were fabricated by a facile and mild strategy. These Janus NPs not only exhibit small shift of the local surface plasmon resonance wavelength but also have high potential for drug loading and low cytotoxicity. More importantly, the Janus nano-composites could efficiently deliver the imaging agents or drugs into liver cancer cells, at the same time the Janus NPs have good effect on photothermal, which indicate that the unique Janus NPs could be a promising candidate of theranostic system for combined photothermo-/chemo-cancer therapy.

  10. Laser-fabricated gold nanoparticles for lateral flow immunoassays.

    Science.gov (United States)

    Cederquist, Kristin B; Liu, Bing; Grima, Megan R; Dalack, Peter J; Mahorn, Jordan T

    2017-01-01

    Gold nanoparticles fabricated by pulsed laser ablation are an attractive alternative over those made by chemical reduction, as they offer a more reactive, chemically-bare surface. In this manuscript, we investigate the interactions of these nanoparticles with different classes of antibodies and quantify surface coverage via a fluorescence-based displacement assay. Saturation surface coverage of monoclonal antibodies was found to be almost 2× higher for particles made by pulsed laser ablation (∼28 antibodies/particle) as opposed to those made by chemical means (∼17 antibodies/particle). This higher coverage translated into ∼2× better immunoassay sensitivity, demonstrated by a sandwich lateral flow assay for human chorionic gonadotropin. This work highlights the advantages of these pulsed laser-fabricated materials and showcases their unique properties for colorimetric assay development. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Uptake and depuration of gold nanoparticles in Daphnia magna

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Kern, Kristina; Hjorth, Rune

    2014-01-01

    This study presents a series of short-term studies (total duration 48 h) of uptake and depuration of engineered nanoparticles (ENP) in neonate Daphnia magna. Gold nanoparticles (Au NP) were used to study the influence of size, stabilizing agent and feeding on uptake and depuration kinetics...... and animal body burdens. 10 and 30 nm Au NP with different stabilizing agents [citrate (CIT) and mercaptoundecanoic acid (MUDA)] were tested in concentrations around 0.5 mg Au/L. Fast initial uptake was observed for all studied Au NP, with CIT stabilized Au NP showing similar rates independent of size...... and MUDA showing increased uptake for the smaller Au NP (MUDA 10 nm > CIT 10 nm, 30 nm > MUDA 30 nm). However, upon transfer to clean media no clear trend on depuration rates was found in terms of stabilizing agent or size. Independent of stabilizing agent, 10 nm Au NP resulted in higher residual whole...

  12. The Deposition of Gold Nanoparticles Onto Activated Carbon

    Directory of Open Access Journals (Sweden)

    Jaworski W.

    2014-10-01

    Full Text Available This work reports the results of spectrophotometric, dynamic light scattering (DLS and microscopic (SEM studies of the gold nanoparticles (AuNPs deposition on activated carbon (AC surface modified with primary (ethanolamine and secondary (diethylenetriamine and triethylenetetramine amines. It was found that this method is efficient for deposition of AuNPs from aqueous solution. However, nanoparticles change their morphology depending on the kind of amine used in experiments. On the AC surface modified with ethanolamine, the uniform spherical AuNPs were formed. In case of diethylenetriamine and triethylenetetramine application, the agglomerates of AuNPs are present. The diameter of individual AuNPs did not exceed 15 nm and was bigger as compared with the diameter of particles present in precursor solution (ca. 10 nm.

  13. Uniform Decoration of Reduced Graphene Oxide Sheets with Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Huanping Yang

    2012-01-01

    Full Text Available A simple method employing ionic liquid functionalization is developed to achieve the uniform decoration of reduced graphene oxide sheets with gold nanoparticles. The synthesis of ionic liquid modified graphene oxide is accomplished by covalently binding 1-(3-Aminopropyl imidazole with GO sheets. The formation mechanism of Au nanoparticles on RGO sheets is proposed to load AuCl4- onto the surface of GO sheets through anion exchange; then reduce AuCl4- to Au NPs and at the same time reduce GO sheets to RGO sheets via a one-step process. The presence of Au NPs is well identified by SEM, TEM, and XPS. As a concept, the RGO-supported Au NPs is applied to surface-enhanced Raman spectroscopy.

  14. Finely tunable fabrication and catalytic activity of gold multipod nanoparticles.

    Science.gov (United States)

    Choi, Soon; Moon, Youngseo; Yoo, Hyojong

    2016-05-01

    Gold multipod nanoparticles (Au Multipod NPs) containing multi-branches with sharp edges and tips were synthesized in high yield through a facile seed-mediated method using cetyltrimethylammonium bromide (CTAB), Brij35, Au seed nanoparticles, Ag(+) ions, ascorbic acid, and sodium salicylate. The branch lengths of Au Multipod NPs were finely controlled by adjusting the molar ratio of mixed surfactants, and in particular by changing the amount of sodium salicylate. A formation mechanism for the star-shaped topologies was proposed and experimentally proved. The catalytic activity of the synthesized Au Multipod NPs was evaluated in ethanol electrooxidation reaction. The dependence of the catalytic performances on the nanostructural morphology was investigated. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Gold Nanoparticles and Microwave Irradiation Inhibit Beta-Amyloid Amyloidogenesis

    Directory of Open Access Journals (Sweden)

    Bastus Neus

    2008-01-01

    Full Text Available Abstract Peptide-Gold nanoparticles selectively attached to β-amyloid protein (Aβ amyloidogenic aggregates were irradiated with microwave. This treatment produces dramatic effects on the Aβ aggregates, inhibiting both the amyloidogenesis and the restoration of the amyloidogenic potential. This novel approach offers a new strategy to inhibit, locally and remotely, the amyloidogenic process, which could have application in Alzheimer’s disease therapy. We have studied the irradiation effect on the amyloidogenic process in the presence of conjugates peptide-nanoparticle by transmission electronic microscopy observations and by Thioflavine T assays to quantify the amount of fibrils in suspension. The amyloidogenic aggregates rather than the amyloid fibrils seem to be better targets for the treatment of the disease. Our results could contribute to the development of a new therapeutic strategy to inhibit the amyloidogenic process in Alzheimer’s disease.

  16. Direct Plasmon-Accelerated Electrochemical Reaction on Gold Nanoparticles.

    Science.gov (United States)

    Wang, Chen; Nie, Xing-Guo; Shi, Yi; Zhou, Yue; Xu, Jing-Juan; Xia, Xing-Hua; Chen, Hong-Yuan

    2017-06-27

    Direct photocatalysis making use of plasmonic metals has attracted significant attention due to the light-harnessing capabilities of these materials associated with localized surface plasmon resonance (LSPR) features. Thus far, most reported work has been limited to plasmon-induced chemical transformations. Herein, we demonstrate that electrochemical reactions can also be accelerated by plasmonic nanoparticles upon LSPR excitation. Using glucose electrocatalysis as a model reaction system, the direct plasmon-accelerated electrochemical reaction (PAER) on gold nanoparticles is observed. The wavelength- and solution-pH-dependent electrochemical oxidation rate and the dark-field scattering spectroscopy results confirm that the hot charge carriers generated during plasmon decay are responsible for the enhanced electrocatalysis performance. Based on the proposed PAER mechanism, a plasmon-improved glucose electrochemical sensor is constructed, demonstrating the enhanced performance of the non-enzyme sensor upon LSPR excitation. This plasmon-accelerated electrochemistry promises potential applications in (bio)electrochemical energy conversion, electroanalysis, and electrochemical devices.

  17. Gold-manganese nanoparticles for targeted diagnostic and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Murph, Simona Hunyadi [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-11-10

    Imagine the possibility of non-invasive, non-radiation based Magnetic resonance imaging (MRI) in combating cardiac disease. Researchers at the Savannah River National Laboratory (SRNL) are developing a process that would use nanotechnology in a novel, targeted approach that would allow MRIs to be more descriptive and brighter, and to target specific organs. Researchers at SRNL have discovered a way to use multifunctional metallic gold-manganese nanoparticles to create a unique, targeted positive contrast agent. SRNL Senior Scientist Dr. Simona Hunyadi Murph says she first thought of using the nanoparticles for cardiac disease applications after learning that people who survive an infarct exhibit up to 15 times higher rate of developing chronic heart failure, arrhythmias and/or sudden death compared to the general population. Without question, nanotechnology will revolutionize the future of technology. The development of functional nanomaterials with multi-detection modalities opens up new avenues for creating multi-purpose technologies for biomedical applications.

  18. Thioctic Acid Derivatives as Building Blocks to Incorporate DNA Oligonucleotides onto Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Sónia Pérez-Rentero

    2014-07-01

    Full Text Available Oligonucleotide gold nanoparticle conjugates are being used as diagnostic tools and gene silencing experiments. Thiol-chemistry is mostly used to functionalize gold nanoparticles with oligonucleotides and to incorporate DNA or RNA molecules onto gold surfaces. However, the stability of such nucleic acid–gold nanoparticle conjugates in certain conditions may be a limitation due to premature break of the thiol-gold bonds followed by aggregation processes. Here, we describe a straightforward synthesis of oligonucleotides carrying thioctic acid moiety based on the use of several thioctic acid-L-threoninol derivatives containing different spacers, including triglycine, short polyethyleneglycol, or aliphatic spacers. The novel thioctic-oligonucleotides were used for the functionalization of gold nanoparticles and the surface coverage and stability of the resulting thioctic-oligonucleotide gold nanoparticles were assessed. In all cases gold nanoparticles functionalized with thioctic-oligonucleotides had higher loadings and higher stability in the presence of thiols than gold nanoparticles prepared with commercially available thiol-oligonucleotides. Furthermore, the thioctic derivative carrying the triglycine linker is sensitive to cathepsin B present in endosomes. In this way this derivative may be interesting for the cellular delivery of therapeutic oligonucleotides as these results provides the basis for a potential endosomal escape.

  19. Inner filter effect of gold nanoparticles on the fluorescence of rare-earth phosphate nanocrystals and its application for determination of biological aminothiols

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong-Qi; Wu, Yong; Yuan, Fei; Xu, Juan; Zhang, Yi-Yan; Wang, Lun, E-mail: wanglun@mail.ahnu.edu.cn

    2013-09-15

    A simple, sensitive fluorescent method for detecting biological aminothiols has been developed based on the inner filter effect principle that utilizes CePO{sub 4}:Tb{sup 3+} luminescent nanoparticles as the donor and gold nanoparticles (AuNPs) as the energy receptor. Stable, water-soluble and well-dispersible CePO{sub 4}:Tb{sup 3+} nanoparticles with low photobleaching features were synthesized conveniently by a facile solvothermal method. At the same time, AuNPs with a high extinction coefficient are expected to be capable of functioning as powerful receptor. Based on the complementary overlap between the emission spectrum of CePO{sub 4}:Tb{sup 3+} nanoparticles and the absorption spectrum of Au NPs, an inner filter effect system was constructed. In the presence of aminothiols (such as cysteine), AuNPs interacted with the aminothiols, thereby inducing the aggregation of AuNPs, which induced the fluorescence recovery. In the present work, we developed a turn-on fluorescent assay for the determination of biological aminothiols. Under the optimum conditions, the linear concentration ranges were 1.0×10{sup −7}–2.0×10{sup −6} M for cysteine, 5.0×10{sup −8}–5.0×10{sup −7} M for glutathione and 8.0×10{sup −8}–1.0×10{sup −6} M for homocysteine, respectively. The method is successfully applied to the quantification of biological aminothiols in synthetic samples. -- Highlights: • An inner filter effect method for detecting biological aminothiols has been developed. • CePO{sub 4}:Tb{sup 3+} nanoparticles were synthesized and used as the donor. • Gold nanoparticles (AuNPs) were synthesized and used as the energy receptor.

  20. Memecylon edule leaf extract mediated green synthesis of silver and gold nanoparticles

    Science.gov (United States)

    Elavazhagan, Tamizhamudu; Arunachalam, Kantha D

    2011-01-01

    We used an aqueous leaf extract of Memecylon edule (Melastomataceae) to synthesize silver and gold nanoparticles. To our knowledge, this is the first report where M. edule leaf broth was found to be a suitable plant source for the green synthesis of silver and gold nanoparticles. On treatment of aqueous solutions of silver nitrate and chloroauric acid with M. edule leaf extract, stable silver and gold nanoparticles were rapidly formed. The gold nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX) and Fourier transform infra-red spectroscopy (FTIR). The kinetics of reduction of aqueous silver and gold ions during reaction with the M. edule leaf broth were easily analyzed by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to M. edule leaf broth, were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20–50 nm. TEM analysis of gold nanoparticles showed formation of triangular, circular, and hexagonal shapes in the size range 10–45 nm. The resulting silver nanoparticles were predominantly square with uniform size range 50–90 nm. EDAX results confirmed the presence of triangular nanoparticles in the adsorption peak of 2.30 keV. Further FTIR analysis was also done to identify the functional groups in silver and gold nanoparticles. The characterized nanoparticles of M. edule have potential for various medical and industrial applications. Saponin presence in aqueous extract of M. edule is responsible for the mass production of silver and gold nanoparticles. PMID:21753878

  1. Photoinduced charge and energy transfer in phthalocyanine-functionalized gold nanoparticles

    NARCIS (Netherlands)

    Kotiaho, Anne; Lahtinen, Riikka; Efimov, Alexander; Metsberg, Hanna Kaisa; Sariola, Essi; Lehtivuori, Heli; Tkachenko, Nikolai V.; Lemmetyinen, Helge

    2010-01-01

    Photoinduced processes in phthalocyanine-functionalized gold nanoparticles (Pc-AuNPs) have been investigated by spectroscopic measurements. The metal-free phthalocyanines used have two linkers with thioacetate groups for bonding to the gold nanoparticle surface, and the attachment was achieved using

  2. Gold nanoparticle-based fluorescent sensor for the analysis of dithiocarbamate pesticides in water

    DEFF Research Database (Denmark)

    Senkbeil, Silja; Lafleur, Josiane P.; Jensen, Thomas Glasdam

    2012-01-01

    and environmental health. This paper demonstrates the potential of a gold nanoparticle-based microfluidic sensor for in field detection of dithiocarbamate pesticides at remote locations. Combining the attractive optical properties of gold nanoparticles with on chip mixing and detection, using a simple digital...

  3. Gold Nanoparticles: Synthesis, Stability Test, and Application for the Rice Growth

    National Research Council Canada - National Science Library

    Aiwu Wang; Hoi Pong Ng; Yi Xu; Yuyu Li; Yuhong Zheng; Jingping Yu; Fugui Han; Feng Peng; Li Fu

    2014-01-01

    ... properties change and aggregation degree. Herein, we report the synthesis of gold nanoparticles of different shapes and applications for the rice growth with significant difference. The gold nanoparticles can inhibit the elongation of rice root without inhibiting the germination of rice seeds.

  4. Effect on nerve structures of functionalized gold-chitosan nanoparticles obtained by one pot synthesis

    Directory of Open Access Journals (Sweden)

    Marius Dobromir

    2011-02-01

    Full Text Available Gold nanoparticles have potential applications in drug delivery, cancer diagnosis and therapy, food industry and environment remediation. However, little is known about their potential toxicity or fate in the environment. In this study we observed significant effects of functionalized gold-chitosan nanoparticles obtained by one pot synthesis on nerve structures of Wistar rats.

  5. A facile electrochemical route to the preparation of uniform and monoatomic copper shells for gold nanoparticles.

    Science.gov (United States)

    Gründer, Y; Ramasse, Q M; Dryfe, R A W

    2015-02-28

    Copper on gold forms a monolayer deposit via underpotential deposition. For gold particles adsorbed at a liquid-liquid interface this results in a uniform one monolayer thick shell. This approach offers a new route for the uniform functionalisation of nanoparticles and presents a way to probe fundamental processes that underlie nanoparticle synthesis.

  6. Assessment of the In Vivo Toxicity of Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Liau Ian

    2009-01-01

    Full Text Available Abstract The environmental impact of nanoparticles is evident; however, their toxicity due to their nanosize is rarely discussed. Gold nanoparticles (GNPs may serve as a promising model to address the size-dependent biological response to nanoparticles because they show good biocompatibility and their size can be controlled with great precision during their chemical synthesis. Naked GNPs ranging from 3 to 100 nm were injected intraperitoneally into BALB/C mice at a dose of 8 mg/kg/week. GNPs of 3, 5, 50, and 100 nm did not show harmful effects; however, GNPs ranging from 8 to 37 nm induced severe sickness in mice. Mice injected with GNPs in this range showed fatigue, loss of appetite, change of fur color, and weight loss. Starting from day 14, mice in this group exhibited a camel-like back and crooked spine. The majority of mice in these groups died within 21 days. Injection of 5 and 3 nm GNPs, however, did not induce sickness or lethality in mice. Pathological examination of the major organs of the mice in the diseased groups indicated an increase of Kupffer cells in the liver, loss of structural integrity in the lungs, and diffusion of white pulp in the spleen. The pathological abnormality was associated with the presence of gold particles at the diseased sites, which were verified by ex vivo Coherent anti-Stoke Raman scattering microscopy. Modifying the surface of the GNPs by incorporating immunogenic peptides ameliorated their toxicity. This reduction in the toxicity is associated with an increase in the ability to induce antibody response. The toxicity of GNPs may be a fundamental determinant of the environmental toxicity of nanoparticles.

  7. Assembly of citrate gold nanoparticles on hydrophilic monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Vikholm-Lundin, Inger, E-mail: inger.vikholm-lundin@uta.fi [University of Tampere, BioMediTech, Tampere (Finland); Fimlab Laboratories Ltd., Tampere (Finland); Rosqvist, Emil; Ihalainen, Petri [Abo Akademi University, Center for Functional Materials, Laboratory of Physical Chemistry (Finland); Munter, Tony [VTT Technical Research Centre of Finland, Process Chemistry end Environmental Engineering, Tampere (Finland); Honkimaa, Anni [University of Tampere, Department of Virology, School of Medicine, Tampere (Finland); Marjomäki, Varpu [University of Jyväskylä, Department of Biological and Environmental Science, Nanoscience Center, Jyväskylä (Finland); Albers, Willem M. [BioNavis Oy Ltd., Ylöjärvi, Tampere (Finland); Peltonen, Jouko [Abo Akademi University, Center for Functional Materials, Laboratory of Physical Chemistry (Finland)

    2016-08-15

    Highlights: • The self-assembled layers were all hydrophilic with Lipa-pTHMMAA exhibiting close to full wetting. • The polyacrylamide layers smoothen the gold surface to a higher extent than the polyethylene glycol and lipoic acid terminated with an amino group. • SPR resonance curves shift to higher angles and become increasingly damped when large nanoparticles assembled on the surface. • Topographical images confirmed that the highest number of particles were assembled on the polyethylene glycol monolayer. • By increasing the interaction time more particles could be assembled on the surface. - Abstract: Self-assembled monolayers (SAMs) as model surfaces were linked onto planar gold films thorough lipoic acid or disulfide groups. The molecules used were polyethylene glycol (EG-S-S), N-[tris-(hydroxymethyl)methyl]acrylamide polymers with and without lipoic acid (Lipa-pTHMMAA and pTHMMAA) and a lipoic acid triazine derivative (Lipa-MF). All the layers, but Lipa-MF with a primary amino group were hydroxyl terminated. The layers were characterized by contact angle measurements and atomic force microscopy, AFM. Citrate stabilized nanoparticles, AuNPs in water and phosphate buffer were allowed to assemble on the layers for 10 min and the binding was followed in real-time with surface plasmon resonance, SPR. The SPR resonance curves were observed to shift to higher angles and become increasingly damped, while also the peaks strongly broaden when large nanoparticles assembled on the surface. Both the angular shift and the damping of the curve was largest for nanoparticles assembling on the EG-S-S monolayer. High amounts of particles were also assembled on the pTHMMAA layer without the lipoic acid group, but the damping of the curve was considerably lower with a more even distribution of the particles. Topographical images confirmed that the highest number of particles were assembled on the polyethylene glycol monolayer. By increasing the interaction time more

  8. Gold and silver nanoparticles based superquenching of fluorescence: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debanjana; Chattopadhyay, Nitin, E-mail: nitin.chattopadhyay@yahoo.com

    2015-04-15

    The short review highlights the recent advances on the gold and silver nanoparticles induced efficient quenching of fluorescence from various fluorophores looking at their promising use as optical rulers and chemo-/bio- sensors. The fluorescence quenching often leads to the increase in the Stern–Volmer constant (K{sub SV}~10{sup 7}–10{sup 10} mol{sup −1} dm{sup 3}) several orders of magnitude higher than the values observed for the normal photochemical quenching processes (~10{sup 2} mol{sup −1} dm{sup 3}). This amplified quenching has been termed as “super-quenching” or “hyper-quenching”. Energy transfer (ET) is established from the donor to the metal nanoparticles rationalizing these fast quenching processes. Considering the distance dependence of the ET process, Förster resonance energy transfer (FRET) and nanometal surface energy transfer (NSET) are ascribed to take place. These sensitive distance dependent phenomena serve as the spectroscopic ruler to measure the intra- or intermolecular distances between the interacting partners. In this account focus has been laid on the size dependent energy transfer and super- and hyper- quenching of the fluorescence of the donor moieties by the nanometals and their probable applications in sensing. Rationalization has been made for the nanoparticle induced huge enhancement in the quenching efficiency. The impact of this review lies in the possible application of these amplified quenching processes in designing high sensitive chemical and biological sensors. - Highlights: • Super efficient quenching of fluorescence of probes by gold and silver nanoparticles is highlighted. • The amplified fluorescence quenching of dyes and polymers is rationalized. • Energy transfer is assigned to be responsible for the efficient quenching process. • Amplified quenching has its potential use in designing sensitive chemical/biological sensors.

  9. Water soluble azido polyisocyanides as functional beta-sheet mimics

    NARCIS (Netherlands)

    Schwartz, Erik; Schwartz, E.; Koepf, Matthieu; Kitto, Heather J.; Espelt, Mónica; Nebot-Carda, Vicent J.; de Gelder, Rene; Nolte, Roeland J.M.; Cornelissen, Jeroen Johannes Lambertus Maria; Rowan, Alan E.

    2009-01-01

    The design and synthesis of functional biomimetic water soluble polymers with a defined secondary structure has been developed using β-sheet polyisocyanopeptide scaffolds. Water soluble isocyanopolymers were prepared by random copolymerisation of the azido functionalized isocyanopeptides with

  10. Smart mesoporous silica nanoparticles gated by pillararene-modified gold nanoparticles for on-demand cargo release.

    Science.gov (United States)

    Wang, Xin; Tan, Li-Li; Li, Xi; Song, Nan; Li, Zheng; Hu, Jia-Na; Cheng, Yi-Ming; Wang, Yan; Yang, Ying-Wei

    2016-12-11

    A new drug delivery system, based on mesoporous silica nanoparticles gated by carboxylatopillar[5]arene-modified gold nanoparticles, has been fabricated, which demonstrated good responses to competitive binding and temperature variation. This multifunctional nanosystem combines the excellent characteristics of two kinds of nanoparticles and utilizes a supramolecular host-guest approach for on-demand cargo release.

  11. Use of Soybean Lecithin in Shape Controlled Synthesis of Gold Nanoparticles

    Science.gov (United States)

    Ayres, Benjamin Robert

    The work presented in this dissertation is a composite of experiments in the growth of gold nanoparticles with specific optical properties of interest. The goal is to synthesize these gold nanoparticles using soybean extract for not only shape control, but for propensity as a biocompatible delivery system. The optical properties of these nanoparticles has found great application in coloring glass during the Roman empire and, over the centuries, has grown into its own research field in applications of nanoparticulate materials. Many of the current functions include use in biological systems as biosensors and therapeutic applications, thus making biocompatibility a necessity. Current use of cetyltrimethylammonium bromide leads to rod-shaped gold nanoparticles, however, the stability of these gold nanoparticles does not endure for extended periods of time in aqueous media. In my research, two important components were found to be necessary for stable, anisotropic growth of gold nanoparticles. In the first experiments, it was found that bromide played a key role in shape control. Bromide exchange on the gold atoms led to specific packing of the growing crystals, allowing for two-dimensional growth of gold nanoparticles. It was also discerned that soybean lecithin contained ligands that blocked specific gold facets leading to prismatic gold nanoparticle growth. These gold nanoprisms give a near infrared plasmon absorption similar to that of rod-shaped gold nanoparticles. These gold nanoprisms are discovered to be extremely stable in aqueous media and remain soluble for extended periods of time, far longer than that of gold nanoparticles grown using cetyltrimethylammonium bromide. Since soy lecithin has a plethora of compounds present, it became necessary to discover which compound was responsible for the shape control of the gold nanoprisms in order to optimize the synthesis and allow for a maximum yield of the gold nanoprisms. Many of these components were identified

  12. Polymer supported gold nanoparticles: Synthesis and characterization of functionalized polystyrene-supported gold nanoparticles and their application in catalytic oxidation of alcohols in water

    Science.gov (United States)

    Kaboudin, Babak; Khanmohammadi, Hamid; Kazemi, Foad

    2017-12-01

    Sulfonated polystyrene microsphere were functionalized using ethylene diamine to introduce amine groups to the polymer chains. The amine functionalized polymers were used as a support for gold nanoparticles. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, EDS, CHN and atomic absorption spectroscopy. The polymer supported gold nanoparticles was found to be an efficient catalyst for the oxidation of alcohols in water.

  13. Not all that glitters is gold - Electron microscopy study on uptake of gold nanoparticles in Daphnia magna and related artefacts

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard; Skjolding, Lars Michael; Thit, Amalie

    2017-01-01

    techniques are used to investigate internalization of 10 nm gold nanoparticles in Daphnia magna gut lumen and gut epithelial cells upon 24h exposure and outline potential artefacts, i.e. high contract precipitates from sample preparation related to these techniques. Light sheet microscopy confirmed......, permitting only single particles through. Structures resembling nanoparticles were also observed inside gut cells. As elemental analysis could not verify these to be gold they were likely artifacts from the preparation, such as osmium and iron. Importantly, gold nanoparticles were in fact found inside...... holocrine cells with disrupted membranes. Thus, false positive observations of nanoparticle internalization may result from either preparation artefacts or by mistaking disrupted cells for intact. These findings emphasize the importance of cell integrity and combining elemental analysis...

  14. Plasmonic properties of gold nanoparticles covered by silicon suboxide thin film

    Science.gov (United States)

    Baranov, Evgeniy; Zamchiy, Alexandr; Safonov, Aleksey; Starinskiy, Sergey; Khmel, Sergey

    2017-10-01

    The optical properties of nanocomposite material consisting of gold nanoparticles without/with silicon suboxide thin film were obtained. The gold film was deposited by thermal vacuum evaporation and then it was annealed in a vacuum chamber to form gold nanoparticles. The silicon suboxide thin films were deposited by the gas-jet electron beam plasma chemical vapor deposition method. The intensity of the localized surface plasmon resonance increased and the plasmon maximum peak shifted from 520 nm to 537 nm.

  15. Laccase-Assisted Rapid Synthesis of Colloidal Gold Nanoparticles for the Catalytic Reduction of 4-Nitrophenol

    OpenAIRE

    Li, Fang; Li, Zheng; Zeng, Chang; Hu, Yonggang

    2017-01-01

    A green method for the rapid preparation of uniform-sized colloidal gold nanoparticles under ambient conditions was presented and validated using laccase as a reduction agent in alkaline medium. UV-Vis spectrophotometry, field-emission high-resolution transmission electron microscopy, X-ray diffraction, selected area electron diffraction, energy dispersive X-ray analysis, zetasizer, and Fourier transform infrared spectroscopy were used to characterize the gold nanoparticles. The gold nanopart...

  16. Grafting of gold onto spin-crossover nanoparticles: SCO@Au.

    Science.gov (United States)

    Moulet, Lucie; Daro, Nathalie; Mornet, Stéphane; Vilar-Vidal, Noelia; Chastanet, Guillaume; Guionneau, Philippe

    2016-11-03

    Nanoparticles of gold were successfully grafted onto nanoparticles of a 1D polymeric spin-crossover material leading to singular SCO@Au hybrid particles. The result is equally obtained using a large range of gold-particle sizes, from 4 to 45 nm, which first allows definition of the best experimental conditions, notably in terms of gold-particle concentration, and then demonstrates the robustness and the efficiency of the method.

  17. Piper betle-mediated green synthesis of biocompatible gold nanoparticles

    Science.gov (United States)

    Punuri, Jayasekhar Babu; Sharma, Pragya; Sibyala, Saranya; Tamuli, Ranjan; Bora, Utpal

    2012-08-01

    Here, we report the novel use of the ethonolic leaf extract of Piper betle for gold nanoparticle (AuNP) synthesis. The successful formation of AuNPs was confirmed by UV-visible spectroscopy, and different parameters such as leaf extract concentration (2%), gold salt concentration (0.5 mM), and time (18 s) were optimized. The synthesized AuNPs were characterized with different biophysical techniques such as transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). TEM experiments showed that nanoparticles were of various shapes and sizes ranging from 10 to 35 nm. FT-IR spectroscopy revealed that AuNPs were functionalized with biomolecules that have primary amine group -NH2, carbonyl group, -OH groups, and other stabilizing functional groups. EDX showed the presence of the elements on the surface of the AuNPs. FT-IR and EDX together confirmed the presence of biomolecules bounded on the AuNPs. Cytotoxicity of the AuNPs was tested on HeLa and MCF-7 cancer cell lines, and they were found to be nontoxic, indicating their biocompatibility. Thus, synthesized AuNPs have potential for use in various biomedical applications.

  18. Design of functionalized gold nanoparticle probes for computed tomography imaging.

    Science.gov (United States)

    Silvestri, Alessandro; Zambelli, Vanessa; Ferretti, Anna M; Salerno, Domenico; Bellani, Giacomo; Polito, Laura

    2016-09-01

    The development of new molecules able to efficiently act as long-circulating computed tomography (CT) contrast agents is one of the most crucial topics in the biomedical field. In the last years, the chance to manipulate materials at the nano-size level gave new boost to this research, with the specific aim to design innovative nanoprobes. Gold nanoparticles (AuNPs) have showed unique X-rays attenuation properties which, combined with their easy surface functionalization, makes them ideal candidates for the next generation of contrast agents. In this paper, we present a rational and facile approach to synthesize engineered and water-stable AuNPs, achieving concentrated colloidal solution with high Hounsfield Units (HU). An accurate control of reagents ratio allowed us to design AuNPs with different shapes, from symmetrical to anisotropic morphology, in a convenient 'one-pot' fashion. Their activity as efficient and reliable CT contrast agents has been evaluated and compared. Moreover, glucosamine-functionalized gold nanoparticles have been developed ([Au] = 31.20 mg/mL; HU = 2453), in order to obtain a CT contrast agent able to combine spatial resolution with metabolic information. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. A gold nanoparticle-linked glycoconjugate vaccine against Burkholderia mallei.

    Science.gov (United States)

    Gregory, Anthony E; Judy, Barbara M; Qazi, Omar; Blumentritt, Carla A; Brown, Katherine A; Shaw, Andrew M; Torres, Alfredo G; Titball, Richard W

    2015-02-01

    Burkholderia mallei are Gram-negative bacteria, responsible for the disease glanders. B. mallei has recently been classified as a Tier 1 agent owing to the fact that this bacterial species can be weaponised for aerosol release, has a high mortality rate and demonstrates multi-drug resistance. Furthermore, there is no licensed vaccine available against this pathogen. Lipopolysaccharide (LPS) has previously been identified as playing an important role in generating host protection against Burkholderia infection. In this study, we present gold nanoparticles (AuNPs) functionalised with a glycoconjugate vaccine against glanders. AuNPs were covalently coupled with one of three different protein carriers (TetHc, Hcp1 and FliC) followed by conjugation to LPS purified from a non-virulent clonal relative, B. thailandensis. Glycoconjugated LPS generated significantly higher antibody titres compared with LPS alone. Further, they improved protection against a lethal inhalation challenge of B. mallei in the murine model of infection. Burkholderia mallei is associated with multi-drug resistance, high mortality and potentials for weaponization through aerosol inhalation. The authors of this study present gold nanoparticles (AuNPs) functionalized with a glycoconjugate vaccine against this Gram negative bacterium demonstrating promising results in a murine model even with the aerosolized form of B. Mallei. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Asymmetric gold nanoparticle reduction into polydimethylsiloxane thin films

    Science.gov (United States)

    Dunklin, Jeremy R.; Forcherio, Gregory T.; Berry, Keith R.; Roper, D. Keith

    2014-09-01

    Polymer thin films embedded with plasmonic gold nanoparticles (AuNPs) are of significant interest in biomedicine, optics, photovoltaic, and nanoelectromechanical systems. Thin polydimethylsiloxane (PDMS) films containing 3-7 micron layers of AuNPs that were fabricated with a novel diffusive-reduction synthesis technique attenuated up to 85% of incoming laser light at the plasmon resonance. Rapid diffusive reduction of AuNPs into asymmetric PDMS thin films provided superior optothermal capabilities relative to thicker films in which AuNPs were reduced throughout. A photonto- heat conversion of up to 3000°C/watt was demonstrated, which represents a 3-230-fold increase over previous AuNPfunctionalized systems. Optical attenuation and thermal response increased in proportion to order of magnitude increases in tetrachloroaurate (TCA) solution concentration. Optical and thermoplasmonic responses were observed with and without an adjacent mesh support, which increased attenuation but decreased thermal response. Morphological, optical, and thermoplasmonic properties of asymmetric AuNP-PDMS films varied significantly with diffusive TCA concentration. Gold nanoparticles, networks, and conglomerates were formed via reduction as the amount of dissolved TCA increased across a log10-scale. Increasing TCA concentrations caused polymer surface cratering, leading to a larger effective surface area. This method, utilizing the diffusion of TCA into a single exposed partially cured PDMS interface, could be used to replace expensive lithographic or solution synthesis of plasmon-functionalized systems.

  1. The Green synthesis of gold nanoparticles using an aqueous root extract of Morinda citrifolia L

    Science.gov (United States)

    Suman, T. Y.; Radhika Rajasree, S. R.; Ramkumar, R.; Rajthilak, C.; Perumal, P.

    2014-01-01

    In the present work, we describe the synthesis of gold nanoparticles using an aqueous root extract of Morinda citrifolia. UV-vis spectroscopy, XRD, FTIR, FE-SEM, EDX and TEM were performed to characterize the formation of gold nanoparticles. The synthesized gold nanoparticles were characterized by a peak at 540 nm in the UV-vis spectrum. The XRD peaks at 38°, 44°, 64° and 77° can be indexed to the (1 1 1), (2 0 0), (2 2 0) and (3 1 1) Bragg's reflections of cubic structure of metallic gold, respectively. The FTIR result showed that extract containing protein might be responsible for the formation of the nanoparticles and may play an important role in the stabilization of the formed nanoparticles. FESEM images revealed that the particles were triangle and mostly spherical in shape. TEM images clearly revealed the size of the nanoparticles were 12.17-38.26 nm in size.

  2. The Green synthesis of gold nanoparticles using an aqueous root extract of Morinda citrifolia L.

    Science.gov (United States)

    Suman, T Y; Rajasree, S R Radhika; Ramkumar, R; Rajthilak, C; Perumal, P

    2014-01-24

    In the present work, we describe the synthesis of gold nanoparticles using an aqueous root extract of Morinda citrifolia. UV-vis spectroscopy, XRD, FTIR, FE-SEM, EDX and TEM were performed to characterize the formation of gold nanoparticles. The synthesized gold nanoparticles were characterized by a peak at 540 nm in the UV-vis spectrum. The XRD peaks at 38°, 44°, 64° and 77° can be indexed to the (111), (200), (220) and (311) Bragg's reflections of cubic structure of metallic gold, respectively. The FTIR result showed that extract containing protein might be responsible for the formation of the nanoparticles and may play an important role in the stabilization of the formed nanoparticles. FESEM images revealed that the particles were triangle and mostly spherical in shape. TEM images clearly revealed the size of the nanoparticles were 12.17-38.26 nm in size. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Surface Plasmons and Surface Enhanced Raman Spectra of Aggregated and Alloyed Gold-Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Y. Fleger

    2009-01-01

    Full Text Available Effects of size, morphology, and composition of gold and silver nanoparticles on surface plasmon resonance (SPR and surface enhanced Raman spectroscopy (SERS are studied with the purpose of optimizing SERS substrates. Various gold and silver films made by evaporation and subsequent annealing give different morphologies and compositions of nanoparticles and thus different position of the SPR peak. SERS measurements of 4-mercaptobenzoic acid obtained from these films reveal that the proximity of the SPR peak to the exciting laser wavelength is not the only factor leading to the highest Raman enhancement. Silver nanoparticles evaporated on top of larger gold nanoparticles show higher SERS than gold-silver alloyed nanoparticles, in spite of the fact that the SPR peak of alloyed nanoparticles is narrower and closer to the excitation wavelength. The highest Raman enhancement was obtained for substrates with a two-peak particle size distribution for excitation wavelengths close to the SPR.

  4. Extracellular biosynthesis of gold and silver nanoparticles using Krishna tulsi ( Ocimum sanctum) leaf

    Science.gov (United States)

    Philip, Daizy; Unni, C.

    2011-05-01

    Aqueous extract of Ocimum sanctum leaf is used as reducing agent for the environmentally friendly synthesis of gold and silver nanoparticles. The nanoparticles were characterized using UV-vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. These methods allow the synthesis of hexagonal gold nanoparticles having size ∼30 nm showing two surface plasmon resonance (SPR) bands by changing the relative concentration of HAuCl 4 and the extract. Broadening of SPR is observed at larger quantities of the extract possibly due to biosorption of gold ions. Silver nanoparticles with size in the range 10-20 nm having symmetric SPR band centered around 409 nm are obtained for the colloid synthesized at room temperature at a pH of 8. Crystallinity of the nanoparticles is confirmed from the XRD pattern. Biomolecules responsible for capping are different in gold and silver nanoparticles as evidenced by the FTIR spectra.

  5. Preparation, Physicochemical Characterization and Performance Evaluation of Gold Nanoparticles in Radiotherapy

    Directory of Open Access Journals (Sweden)

    Ali Kamiar

    2013-08-01

    Full Text Available Purpose: The aim of the present study was preparation, physicochemical characterization and performance evaluation of gold nanoparticles (GNPs in radiotherapy. Another objective was the investigation of anti-bacterial efficacy of gold nanoparticle against E. coli clinical strains. Methods: Gold nanoparticles prepared by controlled reduction of an aqueous HAuCl4 solution using Tri sodium citrate. Particle size analysis and Transmission electron microscopy were used for physicochemical characterization. Polymer gel dosimetry was used for evaluation of the enhancement of absorbed dose. Diffusion method in agar media was used for investigation of anti-bacterial effect. Results: Gold nanoparticles synthesized in size range from 57 nm to 346 nm by planning different formulation. Gold nanoparticle in 57 nm size increased radiation dose effectiveness with the magnitude of about 21 %. At the concentration of 400 ppm, Nano gold exhibited significant anti-bacterial effect against E. coli clinical strains. Conclusion: It is concluded that gold nanoparticles can be applied as dose enhancer in radiotherapy. The Investigation of anti-bacterial efficacy showed that gold nanoparticle had significant effect against E. coli clinical strains.

  6. In situ gold nanoparticles formation: contrast agent for dental optical coherence tomography

    Science.gov (United States)

    Braz, Ana K. S.; Araujo, Renato E. de; Ohulchanskyy, Tymish Y.; Shukla, Shoba; Bergey, Earl J.; Gomes, Anderson S. L.; Prasad, Paras N.

    2012-06-01

    In this work we demonstrate the potential use of gold nanoparticles as contrast agents for the optical coherence tomography (OCT) imaging technique in dentistry. Here, a new in situ photothermal reduction procedure was developed, producing spherical gold nanoparticles inside dentinal layers and tubules. Gold ions were dispersed in the primer of commercially available dental bonding systems. After the application and permeation in dentin by the modified adhesive systems, the dental bonding materials were photopolymerized concurrently with the formation of gold nanoparticles. The gold nanoparticles were visualized by scanning electron microscopy (SEM). The SEM images show the presence of gold nanospheres in the hybrid layer and dentinal tubules. The diameter of the gold nanoparticles was determined to be in the range of 40 to 120 nm. Optical coherence tomography images were obtained in two- and three-dimensions. The distribution of nanoparticles was analyzed and the extended depth of nanosphere production was determined. The results show that the OCT technique, using in situ formed gold nanoparticles as contrast enhancers, can be used to visualize dentin structures in a non-invasive and non-destructive way.

  7. Production of gold nanoparticles by Streptomyces djakartensis isolate B-5

    Directory of Open Access Journals (Sweden)

    Sara Biglari

    2014-09-01

    Full Text Available  Objective(s: Biosynthesis of gold nanoparticles (NGPs is environmentally safer than chemical and physical procedures. This method requires no use of toxic solvents and synthesis of dangerous products and is environmentally safe. In this study, we report the biosynthesis of NGPs using Streptomyces djakartensis isolate B-5. Materials and Methods: NGPs were biosynthesized by reducing aqueous gold chloride solution via a Streptomyces isolate without the need for any additive for protecting nanoparticles from aggregation. We characterized the responsible Streptomycete; its genome DNA was isolated, purified and 16S rRNA was amplified by PCR. The amplified isolate was sequenced; using the BLAST search tool from NCBI, the microorganism was identified to species level. Results: Treating chloroauric acid solutions with this bacterium resulted in reduction of gold ions and formation of stable NGPs. TEM and SEM electro micrographs of NGPs indicated size range from 2- 25 nm with average of 9.09 nm produced intracellular by the bacterium. SEM electro micrographs revealed morphology of spores and mycelia. The amplified PCR fragment of 16S rRNA gene was cloned and sequenced from both sides; it consisted of 741 nucleotides. According to NCBI GenBank, the bacterium had 97.1% homology with Streptomyces djakartensis strain RT-49. The GenBank accession number for partial 16S rRNA gene was recorded as JX162550. Conclusion: Optimized application of such findings may create applications of Streptomycetes for use as bio-factories in eco-friendly production of NGPs to serve in demanding industries and related biomedical areas. Research in this area should also focus on the unlocking the full mechanism of NGPs biosynthesis by Streptomycetes.

  8. Targeted Therapy Combined with Immune Modulation Using Gold Nanoparticles for Treating Metastatic Colorectal Cancer

    Science.gov (United States)

    2017-09-01

    stimulate the body’s immune system to target and attack cancer cells. Another part of our research includes coating these gold nanoparticles with...AWARD NUMBER: W81XWH-16-1-0427 TITLE: Targeted Therapy Combined with Immune Modulation Using Gold Nanoparticles for Treating Metastatic Colorectal... Nanoparticles for Treating Metastatic Colorectal Cancer 5b. GRANT NUMBER W81XWH-16-1-0427 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Branden Moriarity, Tim

  9. Novel fluorinated ligands for gold nanoparticle labelling with application in 19F-MRI.

    OpenAIRE

    Michelena Olatz; Padro Daniel; Carrillo-Carrión Carolina; del Pino Pablo; Blanco Jorge; Arnáiz Blanca; Parak Wolfgang J.; Carril Monica

    2017-01-01

    Novel fluorinated ligands for gold nanoparticle labelling have been designed and synthesised. Several types of gold nanoparticles have been prepared in the presence of these fluorinated ligands alone, or in combination with non-fluorinated ligands. Their colloidal stability in water and other solvents was tested and the magnetic resonance properties of the so-obtained nanoparticles were also assessed in detail. H-1 and F-19-NMR spectra were evaluated and MRI phantoms of the most promising nan...

  10. Substrate decomposition in galvanic displacement reaction: Contrast between gold and silver nanoparticle formation

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Tapas; Satpati, Biswarup, E-mail: biswarup.satpati@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700 064 (India); Kabiraj, D. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India)

    2015-06-24

    We have investigated substrate decomposition during formation of silver and gold nanoparticles in galvanic displacement reaction on germanium surfaces. Silver and gold nanoparticles were synthesized by electroless deposition on sputter coated germanium thin film (∼ 200 nm) grown initially on silicon substrate. The nanoparticles formation and the substrate corrosion were studied using scanning transmission electron microscopy (STEM) and the energy dispersive X-ray (EDX) spectroscopy.

  11. Gold Nanoparticles Generated in Ethosome Bilayers, As Revealed by Cryo-Electron-Tomography

    OpenAIRE

    de la Presa, Patricia; Rueda, Tatiana; Morales, Maria del Puerto; Chichon, F. Javier; Arranz, Rocio; Valpuesta, Jose Maria; Hernando, Antonio

    2009-01-01

    Gold nanoparticles have been synthesized inside ethosomes, vesicles composed of phospholipid, ethanol and water, which could be very efficient not only in delivery probes to the skin but also as diagnostic and therapeutic multimodal agents. High efficiency encapsulation of gold nanoparticles is achieved by a simple strategy: the nanoparticles synthesis occurs simultaneously with the ethosomes formation, in the absence of any undesirable reducing agents. A three-dimensional reconstruction of a...

  12. Green synthesis of gold nanoparticles using Stevia rebaudiana leaf extracts: Characterization and their stability.

    Science.gov (United States)

    Sadeghi, Babak; Mohammadzadeh, M; Babakhani, B

    2015-07-01

    Various methods invented and developed for the synthesis of gold nanoparticles that increases daily consumed. According to this method, including potential environmental pollution problems and the complexity of the synthesis, in this study, the feasibility of using the leaves extract of Stevia rebaudiana (SR) for the reduction of gold ions to nanoparticles form have been studied. Stevia leaves were used to prepare the aqueous extract for this study. Gold nanoparticles were characterized with different techniques such as UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 5 to 20 nm. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary amine group (NH2), carbonyl group, OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles with size of 17 nm. The scanning electron microscopy (SEM) implies the right of forming gold nanoparticles. The results, confirm that gold nanoparticles have synthesized by the leaves extract of S. rebaudiana (SR). Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Green Chemistry Approach for the Synthesis of Gold Nanoparticles Using the Fungus Alternaria sp.

    Science.gov (United States)

    Dhanasekar, Naresh Niranjan; Rahul, Ganga Ravindran; Narayanan, Kannan Badri; Raman, Gurusamy; Sakthivel, Natarajan

    2015-07-01

    The synthesis of gold nanoparticles has gained tremendous attention owing to their immense applications in the field of biomedical sciences. Although several chemical procedures are used for the synthesis of nanoparticles, the release of toxic and hazardous by-products restricts their use in biomedical applications. In the present investigation, gold nanoparticles were synthesized biologically using the culture filtrate of the filamentous fungus Alternaria sp. The culture filtrate of the fungus was exposed to three different concentrations of chloroaurate ions. In all cases, the gold ions were reduced to Au(0), leading to the formation of stable gold nanoparticles of variable sizes and shapes. UV-Vis spectroscopy analysis confirmed the formation of nanoparticles by reduction of Au(3+) to Au(0). TEM analysis revealed the presence of spherical, rod, square, pentagonal, and hexagonal morphologies for 1 mM chloroaurate solution. However, quasi-spherical and spherical nanoparticles/heart-like morphologies with size range of about 7-13 and 15-18 nm were observed for lower molar concentrations of 0.3 and 0.5 mM gold chloride solution, respectively. The XRD spectrum revealed the face-centered cubic crystals of synthesized gold nanoparticles. FT-IR spectroscopy analysis confirmed the presence of aromatic primary amines, and the additional SPR bands at 290 and 230 nm further suggested that the presence of amino acids such as tryptophan/tyrosine or phenylalanine acts as the capping agent on the synthesized mycogenic gold nanoparticles.

  14. Root extracts of Polygala tenuifolia for the green synthesis of gold nanoparticles.

    Science.gov (United States)

    Jun, Sang Hui; Kim, Hyun-Seok; Koo, Yean Kyoung; Park, Yohan; Kim, Jinwoong; Cho, Seonho; Park, Youmie

    2014-08-01

    Traditional medicinal plants possess diverse active constituents for exerting their biological activities. Recently, the innovative applications of plant extracts have revealed their promise as 'green' reducing agents for the reduction of metal ions during the synthesis of metallic nanoparticles. Herein, we report the use of 70% ethanol extracts from Polygala tenuifolia roots as a 'green' reducing agent for the production of gold nanoparticles by reducing gold(III) chloride trihydrate. Gold nanoparticles were characterized using UV-Visible spectrophotometry, high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The gold nanoparticles had characteristic surface plasmon resonance bands at 535 nm. HR-TEM and AFM images revealed major spherical-shaped nanoparticles. The average diameter was measured to be 9.77±3.09 nm using HR-TEM images. The crystalline structure of the gold nanoparticles was confirmed through lattice fringes and circular spots within the selected area electron diffraction in the HR-TEM images along with the XRD peaks. The gold nanoparticles exhibited enhanced anticoagulant activity, as assessed by activated partial thromboplastin time. The current method is a straightforward, environmentally friendly, and inexpensive method for the production of gold nanoparticles using extracts from traditional medicinal plants.

  15. A new green chemistry method based on plant extracts to synthesize gold nanoparticles

    Science.gov (United States)

    Montes Castillo, Milka Odemariz

    Extraordinary chemical and physical properties exhibited by nanomaterials, as compared to their bulk counterparts, have made the area of nanotechnology a growing realm in the past three decades. It is the nanoscale size (from 1 to 100 nm) and the morphologies of nanomaterials that provide several properties and applications not possible for the same material in the bulk. Magnetic and optical properties, as well as surface reactivity are highly dependent on the size and morphology of the nanomaterial. Diverse nanomaterials are being widely used in molecular diagnostics as well as in medicine, electronic and optical devices. Among the most studied nanomaterials, gold nanoparticles are of special interest due to their multifunctional capabilities. For instance, spherical gold nanoparticles measuring 15-20 nm in diameter have been studied due to their insulin binding properties. Also, thiol functionalized gold nanoparticles between 5 and 30 nm are used in the detection of DNA. Thus, harnessing the shape and size of gold nanoparticles plays an important role in science and technology. The synthesis of gold nanoparticles via the reduction of gold salts, using citrate or other reducing agents, has been widely studied. In recent years, algae, fungi, bacteria, and living plants have been used to reduce trivalent gold (Au3+) to its zero oxidation state (Au 0) forming gold nanoparticles of different sizes and shapes. In addition, plant biomasses have also been studied for their gold-reducing power and nanoparticle formation. Although there is information about the synthesis of the gold nanoparticles by biologically based materials; to our knowledge, the study of the use of alfalfa extracts has not been reported. This innovation represents a significant improvement; that is an environmentally friendly method that does not use toxic chemicals. Also, the problem of extracting the formed gold nanoparticles from biomaterials is addressed in this research but still remains to be

  16. Toxicity of silver and gold nanoparticles on marine microalgae.

    Science.gov (United States)

    Moreno-Garrido, Ignacio; Pérez, Sara; Blasco, Julián

    2015-10-01

    The increased use of nanomaterials in several novel industrial applications during the last decade has led to a rise in concerns about the potential toxic effects of released engineered nanoparticles (NPs) into the environment, as their potential toxicity to aquatic organisms is just beginning to be recognised. Toxicity of metallic nanoparticles to aquatic organisms, including microalgae, seems to be related to their physical and chemical properties, as well as their behaviour in the aquatic media where processes of dissolution, aggregation and agglomeration can occur. Although the production of these particles has increased considerably in recent years, data on their toxicity on microalgae, especially those belonging to marine or estuarine environments remain scarce and scattered. The literature shows a wide variation of results on toxicity, mainly due to the different methodology used in bioassays involving microalgae. These can range for up to EC50 data, in the case of AgNPs, representing five orders of magnitude. The importance of initial cellular density is also addressed in the text, as well as the need for keeping test conditions as close as possible to environmental conditions, in order to increase their environmental relevance. This review focuses on the fate and toxicity of silver, gold, and gold-silver alloy nanoparticles on microalgae, as key organisms in aquatic ecosystems. It is prompted by their increased production and use, and taking into account that oceans and estuaries are the final sink for those NPs. The design of bioassays and further research in the field of microalgae nanoecotoxicology is discussed, with a brief survey on newly developed technology of green (algae mediated) production of Ag, Au and Ag-Au bimetallic NPs, as well as some final considerations about future research on this field. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Potential therapeutic application of gold nanoparticles in B-chronic lymphocytic leukemia (BCLL: enhancing apoptosis

    Directory of Open Access Journals (Sweden)

    Lu Lichun

    2007-05-01

    Full Text Available Abstract B-Chronic Lymphocytic Leukemia (CLL is an incurable disease predominantly characterized by apoptosis resistance. We have previously described a VEGF signaling pathway that generates apoptosis resistance in CLL B cells. We found induction of significantly more apoptosis in CLL B cells by co-culture with an anti-VEGF antibody. To increase the efficacy of these agents in CLL therapy we have focused on the use of gold nanoparticles (GNP. Gold nanoparticles were chosen based on their biocompatibility, very high surface area, ease of characterization and surface functionalization. We attached VEGF antibody (AbVF to the gold nanoparticles and determined their ability to kill CLL B cells. Gold nanoparticles and their nanoconjugates were characterized using UV-Visible spectroscopy (UV-Vis, transmission electron microscopy (TEM, thermogravimetric analysis (TGA and X-ray photoelectron spectroscopy (XPS. All the patient samples studied (N = 7 responded to the gold-AbVF treatment with a dose dependent apoptosis of CLL B cells. The induction of apoptosis with gold-AbVF was significantly higher than the CLL cells exposed to only AbVF or GNP. The gold-AbVF treated cells showed significant down regulation of anti-apoptotic proteins and exhibited PARP cleavage. Gold-AbVF treated and GNP treated cells showed internalization of the nanoparticles in early and late endosomes and in multivesicular bodies. Non-coated gold nanoparticles alone were able to induce some levels of apoptosis in CLL B cells. This paper opens up new opportunities in the treatment of CLL-B using gold nanoparticles and integrates nanoscience with therapy in CLL. In future, potential opportunities exist to harness the optoelectronic properties of gold nanoparticles in the treatment of CLL.

  18. Phytofabrication of gold nanoparticles assisted by leaves of Suaeda monoica and its free radical scavenging property.

    Science.gov (United States)

    Arockiya Aarthi Rajathi, F; Arumugam, R; Saravanan, S; Anantharaman, P

    2014-06-05

    Development of biologically inspired experimental processes for the synthesis of nanoparticles is evolving into an important branch of nanotechnology. An eco-friendly synthesis of inorganic nanoparticle is a fast growing research in the limb of nanotechnology. In the present study, it is reported that Suaeda monoica leaf mediated synthesis of gold nanoparticles by the reduction of gold ions. The formation of gold nanoparticle was confirmed by color changes from turbid brown to deep purple violet color and a characteristic peak at 535 nm. The morphology and structure of synthesized gold nanoparticles were characterized on Scanning Electron Microscopy (SEM) equipped with a Thermo EDAX attachment, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), (FT-IR), Dynamic Light Scattering (DLS) which reveals that the Au nanoparticles are spherical and the average particle size is 12.96 nm. Crystalline nature of the nanoparticles is confirmed from the XRD pattern. FTIR spectrum indicates that the biomolecules of carboxyl, amine and hydroxyl functional groups involved in the reduction of gold nanoparticles. The biosynthesized gold nanoparticles displayed considerable antioxidant capacity. Copyright © 2014. Published by Elsevier B.V.

  19. Gold nanoparticles delivery in mammalian live cells: a critical review

    Directory of Open Access Journals (Sweden)

    Raphaël Lévy

    2010-02-01

    Full Text Available Functional nanomaterials have recently attracted strong interest from the biology community, not only as potential drug delivery vehicles or diagnostic tools, but also as optical nanomaterials. This is illustrated by the explosion of publications in the field with more than 2,000 publications in the last 2 years (4,000 papers since 2000; from ISI Web of Knowledge, ‘nanoparticle and cell’ hit. Such a publication boom in this novel interdisciplinary field has resulted in papers of unequal standard, partly because it is challenging to assemble the required expertise in chemistry, physics, and biology in a single team. As an extreme example, several papers published in physical chemistry journals claim intracellular delivery of nanoparticles, but show pictures of cells that are, to the expert biologist, evidently dead (and therefore permeable. To attain proper cellular applications using nanomaterials, it is critical not only to achieve efficient delivery in healthy cells, but also to control the intracellular availability and the fate of the nanomaterial. This is still an open challenge that will only be met by innovative delivery methods combined with rigorous and quantitative characterization of the uptake and the fate of the nanoparticles. This review mainly focuses on gold nanoparticles and discusses the various approaches to nanoparticle delivery, including surface chemical modifications and several methods used to facilitate cellular uptake and endosomal escape. We will also review the main detection methods and how their optimum use can inform about intracellular localization, efficiency of delivery, and integrity of the surface capping. Raphaël Lévy is a BBSRC David Phillips Research Fellow at the University of Liverpool. He graduated in Physics at the University Louis Pasteur in Strasbourg (France. In 2002, after a Master in Soft Condensed Matter Physics, he obtained a PhD in Physics at the University Louis Pasteur. He then moved to

  20. Nanophase Segregation of Self-Assembled Monolayers on Gold Nanoparticles.

    Science.gov (United States)

    Meena, Santosh Kumar; Goldmann, Claire; Nassoko, Douga; Seydou, Mahamadou; Marchandier, Thomas; Moldovan, Simona; Ersen, Ovidiu; Ribot, François; Chanéac, Corinne; Sanchez, Clément; Portehault, David; Tielens, Frederik; Sulpizi, Marialore

    2017-07-25

    Nanophase segregation of a bicomponent thiol self-assembled monolayer is predicted using atomistic molecular dynamics simulations and experimentally confirmed. The simulations suggest the formation of domains rich in acid-terminated chains, on one hand, and of domains rich in amide-functionalized ethylene glycol oligomers, on the other hand. In particular, within the amide-ethylene glycol oligomers region, a key role is played by the formation of interchain hydrogen bonds. The predicted phase segregation is experimentally confirmed by the synthesis of 35 and 15 nm gold nanoparticles functionalized with several binary mixtures of ligands. An extensive study by transmission electron microscopy and electron tomography, using silica selective heterogeneous nucleation on acid-rich domains to provide electron contrast, supports simulations and highlights patchy nanoparticles with a trend toward Janus nano-objects depending on the nature of the ligands and the particle size. These results validate our computational platform as an effective tool to predict nanophase separation in organic mixtures on a surface and drive further exploration of advanced nanoparticle functionalization.

  1. Molecularly stabilised ultrasmall gold nanoparticles: synthesis, characterization and bioactivity

    Science.gov (United States)

    Leifert, Annika; Pan-Bartnek, Yu; Simon, Ulrich; Jahnen-Dechent, Willi

    2013-06-01

    Gold nanoparticles (AuNPs) are widely used as contrast agents in electron microscopy as well as for diagnostic tests. Due to their unique optical and electrical properties and their small size, there is also a growing field of potential applications in medical fields of imaging and therapy, for example as drug carriers or as active compounds in thermotherapy. Besides their intrinsic optical properties, facile surface decoration with (bio)functional ligands renders AuNPs ideally suited for many industrial and medical applications. However, novel AuNPs may have toxicological profiles differing from bulk and therefore a thorough analysis of the quantitative structure-activity relationship (QSAR) is required. Several mechanisms are proposed that cause adverse effects of nanoparticles in biological systems. Catalytic generation of reactive species due to the large and chemically active surface area of nanomaterials is well established. Because nanoparticles approach the size of biological molecules and subcellular structures, they may overcome natural barriers by active or passive uptake. Ultrasmall AuNPs with sizes of 2 nm or less may even behave as molecular ligands. These types of potential interactions would imply a size and ligand-dependent behaviour of any nanomaterial towards biological systems. Thus, to fully understand their QSAR, AuNPs bioactivity should be analysed in biological systems of increasing complexity ranging from cell culture to whole animal studies.

  2. Kinetics of protein adsorption on gold nanoparticle with variable protein structure and nanoparticle size

    Science.gov (United States)

    Khan, S.; Gupta, A.; Verma, N. C.; Nandi, C. K.

    2015-10-01

    The spontaneous protein adsorption on nanomaterial surfaces and the formation of a protein corona around nanoparticles are poorly understood physical phenomena, with high biological relevance. The complexity arises mainly due to the poor knowledge of the structural orientation of the adsorbed proteins onto the nanoparticle surface and difficulties in correlating the protein nanoparticle interaction to the protein corona in real time scale. Here, we provide quantitative insights into the kinetics, number, and binding orientation of a few common blood proteins when they interact with citrate and cetyltriethylammoniumbromide stabilized spherical gold nanoparticles with variable sizes. The kinetics of the protein adsorption was studied experimentally by monitoring the change in hydrodynamic diameter and zeta potential of the nanoparticle-protein complex. To understand the competitive binding of human serum albumin and hemoglobin, time dependent fluorescence quenching was studied using dual fluorophore tags. We have performed molecular docking of three different proteins—human serum albumin, bovine serum albumin, and hemoglobin—on different nanoparticle surfaces to elucidate the possible structural orientation of the adsorbed protein. Our data show that the growth kinetics of a protein corona is exclusively dependent on both protein structure and surface chemistry of the nanoparticles. The study quantitatively suggests that a general physical law of protein adsorption is unlikely to exist as the interaction is unique and specific for a given pair.

  3. Water-soluble titanium alkoxide material

    Science.gov (United States)

    Boyle, Timothy J.

    2010-06-22

    A water soluble, water stable, titanium alkoxide composition represented by the chemical formula (OC.sub.6H.sub.6N).sub.2Ti(OC.sub.6H.sub.2(CH.sub.2N(CH.sub.3).sub.2).sub- .3-2,4,6).sub.2 with a theoretical molecular weight of 792.8 and an elemental composition of 63.6% C, 8.1% H, 14.1% N, 8.1% O and 6.0% Ti.

  4. Gold Nanoparticles with Stably Embedded Cu-64 and Their Use in Nanoparticle Research

    DEFF Research Database (Denmark)

    Jensen, A.I.; Frellsen, Anders Floor; Hansen, A. E.

    2016-01-01

    64Cu is a popular radionuclide for PET imaging and when 64Cu2+ is mixed with gold nanoparticles (AuNPs) it adheres to the gold surface. Taking advantage of this, we developed methods to trap the 64Cu within the AuNPs by embedding under additional layers of gold. This resulted in radiolabeling...... onto which they are attached. Radiolabeled 64Cu-AuNPs were prepared in biomedically relevant sizes of 20-30 nm and decorated with three different coatings, in order to investigate their in vivo performance by PET imaging in a murine xenograft model. We found the longest plasma half-life (T½ about 9...... hours) to result from a polyethylene glycol (PEG) coating, while faster elimination from the bloodstream was observed for both a Tween-20 stabilized coating and a zwitterionic coating based on sulfonic acids and quaternary amines. Accordingly, our data concluded the PEG coating to be most benefical...

  5. Synthesis of gold and silver nanoparticles usingMukia maderaspatnaplant extract and its anticancer activity.

    Science.gov (United States)

    Devi, Guruviah Karthiga; Sathishkumar, Kannaiyan

    2017-03-01

    The present investigation reveals the in vitro cytotoxic effect of the biosynthesised metal nanoparticles on the MCF 7 breast cancer cell lines. The gold and silver nanoparticles were synthesised through an environmentally admissible route using the Mukia Maderaspatna plant extract. Initially, the biomolecules present in the plant extract were analysed using phytochemical analysis. Further, these biomolecules reduce the metal ion solution resulting from the formation of metal nanoparticles. The reaction parameters were optimised to control the size of nanoparticles which were confirmed by UV visible spectroscopy. Various instrumental techniques such as Fourier transform-infrared spectroscopy, high resolution transmission electron microscopy, energy dispersive X-ray and scanning electron microscopy were employed to characterise the synthesised gold and silver nanoparticles. The synthesised gold and silver nanoparticles were found to be 20-50 nm and were of different shapes including spherical, triangle and hexagonal. MTT and dual staining assays were carried out with different concentrations (1, 10, 25, 50 and 100 µg/ml) of gold and silver nanoparticles. The results show that the nanoparticles exhibited significant cytotoxic effects with IC 50 value of 44.8 µg/g for gold nanoparticles and 51.3 µg/g for silver nanoparticles. The observations in this study show that this can be developed as a promising nanomaterial in pharmaceutical and healthcare sector.

  6. Analytical detection and biological assay of antileukemic drug using gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraj, V. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India)]. E-mail: rajselva_77@yahoo.co.in; Alagar, M. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India)]. E-mail: mkalagar@yahoo.com; Hamerton, I. [Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2006-11-12

    Gold nanoparticles are reported and evaluated as probes for the detection of anticancer drug 6-mercaptopurine (6-MP). The nature of binding between 6-MP and the gold nanoparticles via complexation is investigated using ultraviolet-visible spectrum, cyclic voltammetry, transmission electron microscopy, fluorescence and Fourier transform infrared (FT-IR) spectroscopy. The bound antileukemic drug is fluorescent and the quenching property of gold nanoparticles could be exploited for biological investigations. The 6-MP-colloidal gold complex is observed to have appreciable antibacterial and antifungal activity against Micrococcus luteus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Aspergillus fumigatus, and Aspergillus niger. The experimental studies suggest that gold nanoparticles have the potential to be used as effective carriers for anticancer drugs.

  7. PVA stabilized gold nanoparticles by use of unexplored albeit conventional reducing agent

    Energy Technology Data Exchange (ETDEWEB)

    Khanna, P.K. [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India)]. E-mail: pkk@cmetindia.org; Gokhale, R. [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Subbarao, V.V.V.S. [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Vishwanath, A. Kasi [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Das, B.K. [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Satyanarayana, C.V.V. [National Chemical Laboratory, Pashan Road, Pune 41108 (India)

    2005-07-15

    Poly(vinyl alcohol) (PVA) stabilized gold nanoparticles have been prepared in aqueous medium using two different reducing viz.; hydrazine hydrate, a stronger reducing agent and sodium formaldehydesulfoxylate (SFS), a slightly weaker reducing agent. SFS is used for first ever time for reduction of gold metal salt. The PVA stabilized gold nanoparticles solutions are wine red to blood red coloured and are stable over a long period of time with no indication of aggregation. The solution shows strong visible light absorptions in the range of 520-540 nm, characteristics of gold nanoparticles. Powder X-ray diffraction patterns of freshly prepared films containing gold nanoparticles indicated particles size to be about 15 nm. Transmission electron microscopy (TEM) of a more than two-week-old sample revealed well-defined non-agglomerated spherical particles of about 50 nm diameter in solutions.

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

    Science.gov (United States)

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

    2011-01-01

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

  9. Durable PROX catalyst based on gold nanoparticles and hydrophobic silica

    KAUST Repository

    Laveille, Paco

    2016-01-20

    3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.

  10. Size-dependent radiosensitization of PEG-coated gold nanoparticles for cancer radiation therapy

    CERN Document Server

    Zhang, Xiao-Dong; Shen, Xiu; Chen, Jie; Sun, Yuan-Ming; Liu, Pei-Xun; Liang, Xing-Jie

    2012-01-01

    Gold nanoparticles have been conceived as a radiosensitizer in cancer radiation therapy, but one of the important questions for primary drug screening is what size of gold nanoparticles can optimally enhance radiation effects. Herein, we perform in vitro and in vivo radiosensitization studies of 4.8, 12.1, 27.3, and 46.6 nm PEG-coated gold nanoparticles. In vitro results show that all sizes of the PEG-coated gold nanoparticles can cause a significant decrease in cancer cell survival after gamma radiation. 12.1 and 27.3 nm PEG-coated gold nanoparticles have dispersive distributions in the cells and have stronger sensitization effects than 4.8 and 46.6 nm particles by both cell apoptosis and necrosis. Further, in vivo results also show all sizes of the PEG-coated gold nanoparticles can decrease tumor volume and weight after 5 Gy radiations, and 12.1 and 27.3 nm PEG-coated gold nanoparticles have greater sensitization effects than 4.8 and 46.6 nm particles, which can lead to almost complete disappearance of the ...

  11. Gold nanoparticles as efficient antimicrobial agents for Escherichia coli and Salmonella typhi

    Directory of Open Access Journals (Sweden)

    Lima Enrique

    2013-01-01

    Full Text Available Abstract Background It is imperative to eliminate bacteria present in water in order to avoid problems in healthy. Escherichia coli and Salmonella typhi bacteria are two common pollutants and they are developing resistance to some of the most used bactericide. Therefore new biocide materials are being tested. Thus, gold nanoparticles are proposed to inhibit the growth of these two microorganisms. Results Gold nanoparticles were supported onto clinoptilolite, mordenite and faujasite zeolites. Content of gold in materials varied between 2.3 and 2.8 wt%. The size, dispersion and roughness of gold nanoparticles were highly dependent of the zeolite support. The faujasite support was the support where the 5 nm nanoparticles were highly dispersed. The efficiency of gold-zeolites as bactericides of Escherichia coli and Salmonella typhi was determined by the zeolite support. Conclusions Gold nanoparticles dispersed on zeolites eliminate Escherichia coli and Salmonella typhi at short times. The biocidal properties of gold nanoparticles are influenced by the type of support which, indeed, drives key parameters as the size and roughness of nanoparticles. The more actives materials were pointed out Au-faujasite. These materials contained particles sized 5 nm at surface and eliminate 90–95% of Escherichia coli and Salmonella typhi colonies.

  12. Direct observation of gold nanoparticle assemblies with the porin MspA on mica.

    Science.gov (United States)

    Basel, Matthew T; Dani, Raj Kumar; Kang, Myungshim; Pavlenok, Mikhail; Chikan, Viktor; Smith, Paul E; Niederweis, Michael; Bossmann, Stefan H

    2009-02-24

    The octameric porin MspA from Mycobacterium smegmatis is sufficiently stable to form a nonmembrane-supported stand-alone porin on mica surfaces. About 98% of all MspA octamers were found to stand upright on mica, with their periplasmic loop regions bound to the hydrophilic mica surface. Both, small (d = 3.7 nm) and large (d = 17 nm) gold nanoparticles bind to MspA, however, in different positions: small gold nanoparticles bind within the MspA pore, whereas the large gold nanoparticles bind to the upper region of MspA. These experiments demonstrate that gold nanoparticles can be positioned at different, well-defined distances from the underlying surface using the MspA pore as a template. These findings represent a significant step toward the use of electrically insulating stable proteins in combination with metal nanoparticles in nanodevices.

  13. Anthelmintic Efficacy of Gold Nanoparticles Derived from a Phytopathogenic Fungus, Nigrospora oryzae

    Science.gov (United States)

    Kar, Pradip Kumar; Murmu, Sanatan; Saha, Saswati; Tandon, Veena; Acharya, Krishnendu

    2014-01-01

    Exploring a green chemistry approach, this study brings to the fore, the anthelmintic efficacy of gold nanoparticles, highlighting the plausible usage of myconanotechnology. Gold nanoparticles of ∼6 to ∼18 nm diameter were synthesized by treating the mycelia-free culture filtrate of the phytopathogenic fungus with gold chloride. Their size and morphology were confirmed by UV-Vis spectroscopy, DLS data, AFM and TEM images. The XRD studies reveal a crystalline nature of the nanoparticles, which are in cubic phase. The FTIR spectroscopic studies before and after the formation of nanoparticles show the presence of possible functional groups responsible for the bio-reduction and capping of the synthesized gold nanoparticles. The latter were tested as vermifugal agents against a model cestode Raillietina sp., an intestinal parasite of domestic fowl. Further, ultrastructural and biochemical parameters were used to corroborate the efficacy study. PMID:24465424

  14. Anthelmintic efficacy of gold nanoparticles derived from a phytopathogenic fungus, Nigrospora oryzae.

    Directory of Open Access Journals (Sweden)

    Pradip Kumar Kar

    Full Text Available Exploring a green chemistry approach, this study brings to the fore, the anthelmintic efficacy of gold nanoparticles, highlighting the plausible usage of myconanotechnology. Gold nanoparticles of ∼6 to ∼18 nm diameter were synthesized by treating the mycelia-free culture filtrate of the phytopathogenic fungus with gold chloride. Their size and morphology were confirmed by UV-Vis spectroscopy, DLS data, AFM and TEM images. The XRD studies reveal a crystalline nature of the nanoparticles, which are in cubic phase. The FTIR spectroscopic studies before and after the formation of nanoparticles show the presence of possible functional groups responsible for the bio-reduction and capping of the synthesized gold nanoparticles. The latter were tested as vermifugal agents against a model cestode Raillietina sp., an intestinal parasite of domestic fowl. Further, ultrastructural and biochemical parameters were used to corroborate the efficacy study.

  15. Improving sensitivity of gold nanoparticle based fluorescence quenching and colorimetric aptasensor by using water resuspended gold nanoparticle.

    Science.gov (United States)

    Liu, Jinchuan; Guan, Zheng; Lv, Zhenzhen; Jiang, Xiaoling; Yang, Shuming; Chen, Ailiang

    2014-02-15

    Gold nanoparticles (AuNPs) based fluorescence quenching or colorimetric aptasensor have been developed for many analytes recently largely because of the ease of detection, high sensitivity, and potential for high-throughput analysis. However, the effects of remnant non-AuNPs components in the colloid gold solution on these assays performance remain unclear. For the first time, we demonstrated that the remnant sodium citrate and the reaction products of three acids play counteractive roles in AuNPs based fluorescence quenching and colorimetric aptasensor in three ways in this study. First, the remnant sodium citrate in the colloid gold solution could increase the fluorescence intensity of FAM labeled on the aptamer that reduce the efficiency of AuNPs fluorescent quenching. Second, the reaction products of citric acid, HCl and ketoglutaric acid reduce the fluorescence recovery by quenching the fluorescence of FAM labeled on the aptamer dissociated from the surface of AuNPs upon addition of target. Lastly, the reaction products of three acids reduce the pH value of the colloid gold solution that reduce the sensitivity of AuNPs based colorimetric aptasensor by increasing the adsorption of aptamer to surface of AuNPs. With sulfadimethoxine and thrombin as model analytes, we found that water resuspended AuNPs can significantly increase the sensitivity by more than 10-fold for AuNPs based fluorescence quenching aptasensor. In the AuNPs based colorimetric aptasensor for sulfadimethoxine using the water resuspended AuNPs, the sensitivity also was increased by 10-fold compared with that of original AuNPs. The findings in this study provide theoretical guidance for further improving AuNPs based fluorescent quenching and colorimetric aptasensor by adjusting the composition of AuNPs solution. © 2013 Elsevier B.V. All rights reserved.

  16. Biofabrication of gold and silver nanoparticles for pharmaceutical applications

    Directory of Open Access Journals (Sweden)

    Hamed Barabadi

    2016-02-01

    Full Text Available Biofabrication by using fungi is an exciting recent interest to develop an eco-friendly production of metallic nanoparticles (NPs for pharmaceutical applications. This study aimed to synthesize and characterize gold (Au and silver (Ag NPs by using Penicillium simplisimum. The fungus was grown in fluid czapek dox broth on shaker at 28 ºC and 200 rpm for ten days. Then the supernatant was separated from the mycelia to convert HAuCl4 and AgNO3 solution into Au and Ag NPs separately. After 24 hours, synthesized Au and Ag NPs were characterized by using UV-Visible Spectroscopy as well as Photon Correlation spectroscopy (PCS involves Polydispersity Index (PDI and zeta potential. The UV-Visible Spectroscopy analysis revealed a plasmon bond peak around 533 nm and 400 nm suggesting formation of Au and Ag NPs, respectively. Furthermore, the PCS analysis showed an average diameter of 68 nm and 76 nm with PDI value of 0.2 and 0.23 for Au and Ag NPs, successively, which demonstrated that the nanoparticles formed with fairly well-defined dimensions and good monodispersity. Besides, a negative zeta potential were found for nanoparticles indicating their stability in the solution. The current approach suggests that the rapid synthesis of nanoparticles would be suitable for developing a green process for mass scale production. Besides, we believe that development of eco-friendly process for the formulation of metallic NPs is an important step in the field of application of nanotechnology and its optimization may make it a potential procedure for industrial production of NPs.

  17. Label-free aptamer-based colorimetric detection of mercury ions in aqueous media using unmodified gold nanoparticles as colorimetric probe

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li; Li, Baoxin; Qi, Yingying; Jin, Yan [Shaanxi Normal University, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Materials Science, Xi' an (China)

    2009-04-15

    We report a simple and sensitive aptamer-based colorimetric detection of mercury ions (Hg{sup 2+}) using unmodified gold nanoparticles as colorimetric probe. It is based on the fact that bare gold nanoparticles interact differently with short single-strand DNA and double-stranded DNA. The anti-Hg{sup 2+} aptamer is rich in thymine (T) and readily forms T-Hg{sup 2+}-T configuration in the presence of Hg{sup 2+}. By measuring color change or adsorption ratio, the bare gold nanoparticles can effectively differentiate the Hg{sup 2+}-induced conformational change of the aptamer in the presence of a given salt with high concentration. The assay shows a linear response toward Hg{sup 2+} concentration through a five-decade range of 1 x 10{sup -4} mol L{sup -1} to 1 x 10{sup -9} mol L{sup -1}. Even with the naked eye, we could identify micromolar Hg{sup 2+} concentrations within minutes. By using the spectrometric method, the detection limit was improved to the nanomolar range (0.6 nM). The assay shows excellent selectivity for Hg{sup 2+} over other metal cations including K{sup +}, Ba{sup 2+}, Ni{sup 2+}, Pb{sup 2+}, Cu{sup 2+}, Cd{sup 2+}, Mg{sup 2+}, Ca{sup 2+}, Zn{sup 2+}, Al{sup 3+}, and Fe{sup 3+}. The major advantages of this Hg{sup 2+} assay are its water-solubility, simplicity, low cost, visual colorimetry, and high sensitivity. This method provides a potentially useful tool for the Hg{sup 2+} detection. (orig.)

  18. Antibacterial nanocarriers of resveratrol with gold and silver nanoparticles.

    Science.gov (United States)

    Park, Sohyun; Cha, Song-Hyun; Cho, Inyoung; Park, Soomin; Park, Yohan; Cho, Seonho; Park, Youmie

    2016-01-01

    This study focused on the preparation of resveratrol nanocarrier systems and the evaluation of their in vitro antibacterial activities. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) for resveratrol nanocarrier systems were synthesized using green synthetic routes. During the synthesis steps, resveratrol was utilized as a reducing agent to chemically reduce gold and silver ions to AuNPs and AgNPs. This system provides green and eco-friendly synthesis routes that do not involve additional chemical reducing agents. Resveratrol nanocarriers with AuNPs (Res-AuNPs) and AgNPs (Res-AgNPs) were observed to be spherical and to exhibit characteristic surface plasmon resonance at 547 nm and at 412-417 nm, respectively. The mean size of the nanoparticles ranged from 8.32 to 21.84 nm, as determined by high-resolution transmission electron microscopy. The face-centered cubic structure of the Res-AuNPs was confirmed by high-resolution X-ray diffraction. Fourier-transform infrared spectra indicated that the hydroxyl groups and C=C in the aromatic ring of resveratrol were involved in the reduction reaction. Res-AuNPs retained excellent colloidal stability during ultracentrifugation and re-dispersion, suggesting that resveratrol also played a role as a capping agent. Zeta potentials of Res-AuNPs and Res-AgNPs were in the range of -20.58 to -48.54 mV. Generally, against Gram-positive and Gram-negative bacteria, the Res-AuNPs and Res-AgNPs exhibited greater antibacterial activity compared to that of resveratrol alone. Among the tested strains, the highest antibacterial activity of the Res-AuNPs was observed against Streptococcus pneumoniae. The addition of sodium dodecyl sulfate during the synthesis of Res-AgNPs slightly increased their antibacterial activity. These results suggest that the newly developed resveratrol nanocarrier systems with metallic nanoparticles show potential for application as nano-antibacterial agents with enhanced activities. Copyright © 2015

  19. Synthesis of PET-PLA/Drug Nanoparticles and Their Effect with Gold Nanoparticles for Controlled Drug Release in Cancer Chemotherapy

    OpenAIRE

    K. Sathish Kumar; V. Selvaraj; M. Alagar

    2008-01-01

    Polyethylene terephthalate-polylactic acid copolymer (PET-PLA) was synthesized from bis (2-hydroxyethyl terephthalate) and L-lactic acid oligomer in the presence of manganese antimony glycoxide as a catalyst. The synthesized PET-PLA copolymer was used for controlled drug release systems with gold nanoparticles. Fluorouracil containing PET-PLA nanocapsules was prepared in the presence of gold nanoparticles by solvent evaporation method. The morphologies of the nanocapsules were characterized u...

  20. Linker-mediated assembly of gold nanoparticles into multimeric motifs

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, Mateusz; Cieplak, Marek [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland); Szymczak, Piotr [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ulica Hoza 69, 00-681 Warsaw (Poland); Thompson, Damien, E-mail: mc@ifpan.edu.pl [Tyndall National Institute, Lee Maltings, University College Cork, Cork (Ireland)

    2011-11-04

    We present a theoretical description of linker-mediated self-assembly of gold nanoparticles (Au-NP). Using mesoscale simulations with a coarse-grained model for the Au NPs and dirhenium-based linker molecules, we investigate the conditions under which large clusters can grow and construct a phase diagram that identifies favorable growth conditions in terms of floating and bound linker concentrations. The findings can be considered as generic, as we expect other NP-linker systems to behave in a qualitatively similar way. In particular, we also discuss the case of antibody-functionalised Au NPs connected by the C-reactive proteins (CRPs). We extract some general rules for NP linking that may aid the production of size- and shape-specific NP clusters for technology applications.

  1. Gold nanoparticles for cancer theranostics — A brief update

    Directory of Open Access Journals (Sweden)

    Ning Zhao

    2016-07-01

    Full Text Available Gold nanoparticles (AuNPs exhibit superior optical and physical properties for more effective treatment of cancer through incorporating both diagnostic and therapeutic functions into one single platform. The ability to passively accumulate on tumor cells provides AuNPs the opportunity to become an attractive contrast agent for X-ray based computed tomography (CT imaging in vivo. Because of facile surface modification, various size and shape of AuNPs have been extensively functionalized and applied as active nanoprobes and drug carriers for cancer targeted theranostics. Moreover, their capabilities on producing photoacoustic (PA signals and photothermal effects have been used to image and treat tumor progression, respectively. Herein, we review the developments of AuNPs as cancer diagnostics and chemotherapeutic drug vector, summarizing strategies for tumor targeting and their applications in vitro and in vivo.

  2. Fluidic Manufacture of Star-Shaped Gold Nanoparticles.

    Science.gov (United States)

    Silvestri, Alessandro; Lay, Luigi; Psaro, Rinaldo; Polito, Laura; Evangelisti, Claudio

    2017-07-21

    Star-shaped gold nanoparticles (StarAuNPs) are extremely attractive nanomaterials, characterized by localized surface plasmon resonance which could be potentially employed in a large number of applications. However, the lack of a reliable and reproducible synthetic protocols for the production of StarAuNPs is the major limitation to their spreading. For the first time, here we present a robust protocol to manufacture reproducible StarAuNPs by exploiting a fluidic approach. Star-shaped AuNPs have been synthesized by means of a seed-less protocol, employing ascorbic acid as reducing agent at room temperature. Moreover, the versatility of the bench-top microfluidic protocol has been exploited to afford hydrophilic, hydrophobic and solid-supported engineered StarAuNPs, by avoiding intermediate NP purifications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Cyclodextrin-Based [1]Rotaxanes on Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yanli Zhao

    2012-08-01

    Full Text Available Transformation of mechanically interlocked molecules (e.g., rotaxanes and catenanes into nanoscale materials or devices is an important step towards their real applications. In our current work, an azobenzene-modified β-cyclodextrin (β-CD derivative that can form a self-inclusion complex in aqueous solution was prepared. The self-included β-CD derivative was then functionalized onto a gold nanoparticle (AuNP surface via a ligand-exchange reaction in aqueous solution, leading to the formation of AuNP-[1]rotaxane hybrids. Corresponding non-self-included β-CD derivative functionalized AuNPs were also developed in a DMF/H2O mixture solution for control experiments. These hybrids were fully characterized by UV-vis and circular dichroism spectroscopies, together with transmission electron microscopy (TEM. The competitive binding behavior of the hybrids with an adamantane dimer was investigated.

  4. Self-organization of gold nanoparticles on silanated surfaces.

    Science.gov (United States)

    Kyaw, Htet H; Al-Harthi, Salim H; Sellai, Azzouz; Dutta, Joydeep

    2015-01-01

    The self-organization of monolayer gold nanoparticles (AuNPs) on 3-aminopropyltriethoxysilane (APTES)-functionalized glass substrate is reported. The orientation of APTES molecules on glass substrates plays an important role in the interaction between AuNPs and APTES molecules on the glass substrates. Different orientations of APTES affect the self-organization of AuNps on APTES-functionalized glass substrates. The as grown monolayers and films annealed in ultrahigh vacuum and air (600 °C) were studied by water contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, UV-visible spectroscopy and ultraviolet photoelectron spectroscopy. Results of this study are fundamentally important and also can be applied for designing and modelling of surface plasmon resonance based sensor applications.

  5. Stability of a gold nanoparticle-DNA system in seawater.

    Science.gov (United States)

    Heo, Jun Hyuk; Kim, Kyung-Il; Lee, Min Hyung; Lee, Jung Heon

    2013-11-01

    We investigated the stability of gold nanoparticles (AuNPs) in seawater. The large amount of Na+, Mg2+, K+, and Ca2+ in seawater makes AuNPs unstable resulting in immediate aggregation. We found that AuNPs become much more stable when they were treated with polyethylene glycol (PEG, MW = 20, 000) before exposure to seawater. The AuNPs maintained stability up to 10 days when they were treated with 16.6% PEG 20000. The AuNP-DNA complex formed in the presence of 3.3% PEG 20000 maintained stability when exposed to seawater. We also demonstrated that the AuNP-DNA complexes can be redispersed after centrifugation and show sequence-specific aggregation in seawater. The results show that the both AuNPs and an AuNP-DNA system can be used in seawater and have the potential to be used to study marine systems.

  6. Signal amplification for impedimetric genosensing using gold-streptavidin nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bonanni, A.; Esplandiu, M.J. [Sensors and Biosensors Group, Department of Chemistry, Universitat Autonoma de Barcelona, Edifici Cn, 08193 Bellaterra, Barcelona (Spain); Valle, M. del [Sensors and Biosensors Group, Department of Chemistry, Universitat Autonoma de Barcelona, Edifici Cn, 08193 Bellaterra, Barcelona (Spain)], E-mail: manel.delvalle@uab.es

    2008-04-20

    Streptavidin-coated gold nanoparticles (strept-AuNPs) were used in this work to amplify the impedimetric signal generated in a biosensor detecting the DNA hybridization event. Probe oligomer was adsorbed onto a graphite epoxy composite (GEC) electrode surface and the impedance measurement was performed in a solution containing the redox marker ferrocyanide/ferricyanide. The biotinylated complementary oligomer was used as target. The change of interfacial charge transfer resistance (R{sub ct}), experimented by the redox marker, was recorded to confirm the hybrid formation. The addition of strept-AuNPs, binding to the target due to the strong streptavidin-biotin interaction, led to a further increment of R{sub ct} thus obtaining significant signal amplification. Strept-AuNPs on the electrode surface were observed by scanning electron microscopy (SEM) after silver enhancement treatment. A competitive binding assay was also performed using unlabelled DNA target to demonstrate its applicability to real sample analysis.

  7. Gold Nanoparticles and Nanocomposites in Clinical Diagnostics Using Electrochemical Methods

    Directory of Open Access Journals (Sweden)

    Pranjal Chandra

    2013-01-01

    Full Text Available Progress and development in clinical diagnostics certainly focus upon the advances in the nanomaterials, particularly gold nanoparticles (AuNPs that offer promise to solve the biocompatible and sensitive detection systems. This paper focuses on the recent application of AuNPs in clinical diagnosis. Various important methods of AuNPs synthesis and their application in clinical detection of various biomolecules using electrochemical detection methods have been described. AuNPs alone and in various composites are also described based on the various biosensors design recently published for the detection of cancer biomarkers, proteins, bacteria, and cancer cells. The effect of AuNPs type and size in clinical detection has also been briefly illustrated.

  8. Self-organization of gold nanoparticles on silanated surfaces

    Directory of Open Access Journals (Sweden)

    Htet H. Kyaw

    2015-12-01

    Full Text Available The self-organization of monolayer gold nanoparticles (AuNPs on 3-aminopropyltriethoxysilane (APTES-functionalized glass substrate is reported. The orientation of APTES molecules on glass substrates plays an important role in the interaction between AuNPs and APTES molecules on the glass substrates. Different orientations of APTES affect the self-organization of AuNps on APTES-functionalized glass substrates. The as grown monolayers and films annealed in ultrahigh vacuum and air (600 °C were studied by water contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, UV–visible spectroscopy and ultraviolet photoelectron spectroscopy. Results of this study are fundamentally important and also can be applied for designing and modelling of surface plasmon resonance based sensor applications.

  9. Uptake of gold nanoparticles in primary human endothelial cells

    DEFF Research Database (Denmark)

    Klingberg, Henrik; Oddershede, Lene B.; Löschner, Katrin

    2015-01-01

    Gold nanoparticles (AuNPs) are relevant in nanomedicine for drug delivery in the vascular system, where endothelial cells are the first point of contact. We investigated the uptake of 80 nm AuNPs in primary human umbilical vein endothelial cells (HUVECs) by flow cytometry, 3D confocal microscopy......, nano-scale 3D-imaging using focused ion beam/scanning electron microscopy (FIB/SEM), and single particle inductively coupled plasma-mass spectrometry (spICP-MS). HUVECs were cultured for 3 h or 24 h in medium with AuNPs in a concentration range of 1.25–10 μg ml−1. There was a concentration...

  10. Alkyl and Aromatic Amines as Digestive Ripening/Size Focusing Agents for Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Christopher Sorensen

    2013-07-01

    Full Text Available Both long chain alkyl thiols and alkyl amines behave as size focusing agents for gold nanoparticles, a process that is under thermodynamic control. However, amines do not oxidize surface gold atoms while thiols do oxidize surface gold to gold(I with evolution of hydrogen gas. Therefore, alkyl amines participate in digestive ripening by a different mechanism. The efficiency of alkyl amines for this process is described and compared, and ultimate gold particle size differences are discussed. Reported herein is a detailed investigation of alkyl chain lengths for alkyl amines, aromatic amines (aniline, and unusually reactive amines (2-phenylethyl amine. Also, two methods of preparation of the crude gold nanoparticles were employed: gold ion reduction/inverse micelle vs. metal vaporization (Solvated Metal Atom Dispersion—SMAD.

  11. Glucomannan-mediated facile synthesis of gold nanoparticles for catalytic reduction of 4-nitrophenol

    Science.gov (United States)

    2014-01-01

    A facile one-pot approach for synthesis of gold nanoparticles with narrow size distribution and good stability was presented by reducing chloroauric acid with a polysaccharide, konjac glucomannan (KGM) in alkaline solution, which is green and economically viable. Here, KGM served both as reducing agent and stabilizer. The effects of KGM on the formation and stabilization of as-synthesized gold nanoparticles were studied systematically by a combination of UV-visible (UV-vis) absorption spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering, and Fourier transform infrared spectroscopy. Furthermore, the gold nanoparticles exhibited a notable catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol. PMID:25177220

  12. Enhanced Antimicrobial and Anticancer Activity of Silver and Gold Nanoparticles Synthesised Using Sargassum incisifolium Aqueous Extracts

    Directory of Open Access Journals (Sweden)

    Mokone Mmola

    2016-12-01

    Full Text Available A detailed, methodical approach was used to synthesise silver and gold nanoparticles using two differently prepared aqueous extracts of the brown algae Sargassum incisifolium. The efficiency of the extracts in producing nanoparticles were compared to commercially available brown algal fucoidans, a major constituent of brown algal aqueous extracts. The nanoparticles were characterised using TEM, XRD and UV/Vis spectroscopy and zeta potential measurements. The rate of nanoparticle formation was assessed using UV/Vis spectroscopy and related to the size, shape and morphology of the nanoparticles as revealed by TEM. The antioxidant, reducing power and total polyphenolic contents of the aqueous extracts and fucoidans were determined, revealing that the aqueous extracts with the highest contents produced smaller, spherical, more monodisperse nanoparticles at a faster rate. The nanoparticles were assessed against two gram-negative bacteria, two gram-positive bacteria and one yeast strain. In contrast to the literature, the silver nanoparticles produced using the aqueous extracts were particularly toxic to Gram-negative bacteria, while the gold nanoparticles lacked activity. The cytotoxic activity of the nanoparticles was also evaluated against cancerous (HT-29, MCF-7 and non-cancerous (MCF-12a cell lines. The silver nanoparticles displayed selectivity, since the MCF-12a cell line was found to be resistant to the nanoparticles, while the cancerous HT-29 cell line was found to be sensitive (10% viability. The gold nanoparticles displayed negligible toxicity.

  13. Xanthan gum stabilized PEGylated gold nanoparticles for improved delivery of curcumin in cancer

    Science.gov (United States)

    Swami Muddineti, Omkara; Kumari, Preeti; Ajjarapu, Srinivas; Manish Lakhani, Prit; Bahl, Rishabh; Ghosh, Balaram; Biswas, Swati

    2016-08-01

    In recent years, gold nanoparticles (AuNPs) have received immense interest in various biomedical applications including drug delivery, photothermal ablation of cancer and imaging agent for cancer diagnosis. However, the synthesis of AuNPs poses challenges due to the poor reproducibility and stability of the colloidal system. In the present work, we developed a one step, facile procedure for the synthesis of AuNPs from hydrogen tetrachloroaurate (III) hydrate (HAuCl4. 3H2O) by using ascorbic acid and xanthan gum (XG) as reducing agent and stabilizer, respectively. The effect of concentrations of HAuCl4, 3H2O, ascorbic acid and methoxy polyethylene glycol-thiol (mPEG800-SH) were optimized and it was observed that stable AuNPs were formed at concentrations of 0.25 mM, 50 μM and 1 mM for HAuCl4.3H2O, ascorbic acid, and mPEG800-SH, respectively. The XG stabilized, deep red wine colored AuNPs (XG-AuNPs) were obtained by drop-wise addition of aqueous solution of ascorbic acid (50 mM) and XG (1.5 mg ml-1). Synthesized XG-AuNPs showed λmax at 540 nm and a mean hydrodynamic diameter of 80 ± 3 nm. PEGylation was performed with mPEG800-SH to obtain PEGylated XG-AuNPs (PX-AuNPs) and confirmed by Ellman’s assay. No significant shift observed in λmax and hydrodynamic diameter between XG-AuNPs and PX-AuNPs. Colloidal stability of PX-AuNPs was studied in normal saline, buffers within a pH range of 1.2-7.4, DMEM complete medium and in normal storage condition at 4 ˚C. Further, water soluble curcumin was prepared using PVP-K30 as solid dispersion and loaded on to PX-AuNPs (CPX-AuNPs), and evaluated for cellular uptake and cytotoxicity in Murine melanoma (B16F10) cells. Time and concentration dependent studies using CPX-AuNPs showed efficient uptake and decreased cell viability compared to free curcumin.

  14. Targeting and molecular imaging of HepG2 cells using surface-functionalized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rathinaraj, Pierson [Auckland University of Technology, Institute of Biomedical Technologies (New Zealand); Lee, Kyubae; Choi, Yuri; Park, Soo-Young [Kyungpook National University, School of Applied Chemical Engineering, Graduate School (Korea, Republic of); Kwon, Oh Hyeong [Kumoh National Institute of Technology, Department of Polymer Science and Engineering (Korea, Republic of); Kang, Inn-Kyu, E-mail: ikkang@knu.ac.kr [Kyungpook National University, School of Applied Chemical Engineering, Graduate School (Korea, Republic of)

    2015-07-15

    Mercaptosuccinic acid (M)-conjugated gold nanoparticles (GM) were prepared and characterized by transmission electron microscope and dynamic light scattering. M was used to improve the monodispersity and non-specific intracellular uptake of nanoparticles. Lactobionic acid (L) was subsequently conjugated to the GM to target preferentially HepG2 cells (liver cancer cells) that express asialoglycoprotein receptors (ASGPR) on their membrane surfaces and facilitate the transit of nanoparticles across the cell membrane. The mean size of lactobionic acid-conjugated gold nanoparticle (GL) was approximately 10 ± 0.2 nm. Finally, the Atto 680 dye (A6) was coupled to the nanoparticles to visualize their internalization into HepG2 cells. The interaction of surface-modified gold nanoparticles with HepG2 cells was studied after culturing cells in media containing the GM or L-conjugated GM (GL)

  15. Ultrafast acousto-plasmonics in gold nanoparticle superlattices

    Science.gov (United States)

    Ruello, P.; Ayouch, A.; Vaudel, G.; Pezeril, T.; Delorme, N.; Sato, S.; Kimura, K.; Gusev, V. E.

    2015-11-01

    We report the investigation of the generation and detection of GHz coherent acoustic phonons in plasmonic gold nanoparticle superlattices (NPSs). The experiments have been performed with an optical femtosecond pump-probe scheme across the optical plasmon resonance of the superlattice. Our experiments allow us to estimate first the fundamental mechanical parameters such as the collective elastic response (sound velocity) of the NPS and the nanocontact elastic stiffness. Furthermore, it appears that the light-induced coherent acoustic-phonon pulse has a typical in-depth spatial extension of about 45 nm which is roughly four times the optical skin depth in gold. The modeling of the transient optical reflectivity indicates that the mechanism of phonons generation is achieved through ultrafast heating of the NPS assisted by light excitation of the volume plasmon polariton. Based on these results, we demonstrate that it is possible to map the photon-electron-phonon interaction in subwavelength nanostructures which, in particular, provides insights on the fundamental properties of these nanometamaterials.

  16. Synthesis and antimicrobial activity of gold nanoparticle conjugates with cefotaxime

    Science.gov (United States)

    Titanova, Elena O.; Burygin, Gennady L.

    2016-04-01

    Gold nanoparticles (GNPs) have attracted significant interest as a novel platform for various applications to nanobiotechnology and biomedicine. The conjugates of GNPs with antibiotics and antibodies were also used for selective photothermal killing of protozoa and bacteria. Also the conjugates of some antibiotics with GNPs decreased the number of bacterial growing cells. In this work was made the procedure optimization for conjugation of cefotaxime (a third-generation cephalosporin antibiotic) with GNPs (15 nm) and we examined the antimicrobial properties of this conjugate to bacteria culture of E. coli K-12. Addition of cefotaxime solution to colloidal gold does not change their color and extinction spectrum. For physiologically active concentration of cefotaxime (3 μg/mL), it was shown that the optimum pH for the conjugation was more than 9.5. A partial aggregation of the GNPs in saline medium was observed at pH 6.5-7.5. The optimum concentration of K2CO3 for conjugation cefotaxime with GNPs-15 was 5 mM. The optimum concentration of cefotaxime was at 0.36 μg/mL. We found the inhibition of the growth of E. coli K12 upon application cefotaxime-GNP conjugates.

  17. Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate

    Directory of Open Access Journals (Sweden)

    Chanchal K. Mitra

    2009-02-01

    Full Text Available We have studied the direct electrochemistry of horseradish peroxidase (HRP coupled to gold nanoparticles (AuNP using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i glutathione and (ii lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP conjugate showed characteristic redox peaks at a gold electrode. It displayed good electrocatalytic response to the reduction of H2O2, with good sensitivity and without any electron mediator. The covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the different concentrations of H2O2 showed the characteristics of Michaelis Menten enzyme kinetics with an optimum pH between 7.0 to 8.0. The preparation of the sensor involves single layer of enzyme, which can be carried out efficiently and is also highly reproducible when compared to other systems involving the layer-by-layer assembly, adsorption or encapsulation of the enzyme. The immobilized AuNP-HRP can be used for immunosensor applications

  18. Microreactors for Gold Nanoparticles Synthesis: From Faraday to Flow

    Directory of Open Access Journals (Sweden)

    Md. Taifur Rahman

    2014-06-01

    Full Text Available The seminal work of Michael Faraday in 1850s transmuted the “Alchemy of gold” into a fascinating scientific endeavor over the millennia, particularly in the past half century. Gold nanoparticles (GNPs arguably hold the central position of nanosciences due to their intriguing size-and-shape dependent physicochemical properties, non-toxicity, and ease of functionalization and potential for wide range of applications. The core chemistry involved in the syntheses is essentially not very different from what Michael Faraday resorted to: transforming ions into metallic gold using mild reducing agents. However, the process of such reduction and outcome (shapes and sizes are intricately dependent on basic operational parameters such as sequence of addition and efficiency of mixing of the reagents. Hence, irreproducibility in synthesis and maintaining batch-to-batch quality are major obstacles in this seemingly straightforward process, which poses challenges in scaling-up. Microreactors, by the virtue of excellent control over reagent mixing in space and time within narrow channel networks, opened a new horizon of possibilities to tackle such problems to produce GNPs in more reliable, reproducible and scalable ways. In this review, we will delineate the state-of-the-art of GNPs synthesis using microreactors and will discuss in length how such “flask-to-chip” paradigm shift may revolutionize the very concept of nanosyntheses.

  19. Biofabrication of gold nanoparticles using marine endophytic fungus -Penicillium citrinum.

    Science.gov (United States)

    Manjunath, Hulikere M; Joshi, Chandrashekhar G; Raju, Narayanappa Govinda

    2017-02-01

    Nanotechnology is one of the promising fields of research and generating new avenues and applications in medicine. Recently, marine floras such as, marine endophytes are gaining the attention of many researchers due to the myriad of bioactive molecules that they possess. In addition, they find applications in many pharmaceutical and cosmetic industries. In this study, they have studied the green synthesis of gold nanoparticles (AuNPs) from Penicillium citrinum ( P. citrinum ) and its antioxidant activity. P. citrinum was isolated from brown algae. The identity of the fungus was established by comparing its 18S rDNA sequence. AuNPs were synthesised using P. citrinum and were characterised by UV-visible spectrophotometer (UV-vis), field emission scanning electron microscope (FESEM), X-ray diffraction, Fourier transform infrared spectroscopy and dynamic light scattering (DLS). AuNPs were tested for free radical scavenging activity by 1,1-diphenyl-2-picrylhydrazyl method. The particle sizes of AuNps were determined by FESEM and DLS. The reduction of gold metal ion was confirmed from the UV-vis spectrum. AuNPs showed significant antioxidant potential and the activity was comparable to the standard ascorbic acid. Further, in vitro and in vivo studies on these AuNPs will help in developing an alternative, cost-effective and acceptable drug for various ailments.

  20. An evidence on G2/M arrest, DNA damage and caspase mediated apoptotic effect of biosynthesized gold nanoparticles on human cervical carcinoma cells (HeLa)

    Energy Technology Data Exchange (ETDEWEB)

    Jeyaraj, M. [Department of Biotechnology and Genetic Engineering, School of Biotechnology, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India); Arun, R. [Department of Biomedical Sciences, Bharathidasan University, Tiruchirappalli 620024 (India); Sathishkumar, G. [Department of Biotechnology and Genetic Engineering, School of Biotechnology, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India); MubarakAli, D. [Central Inter-Disciplinary Research Facility, Mahatma Gandhi Medical College and Research Institute Campus, Pondicherry 607402 (India); Rajesh, M.; Sivanandhan, G.; Kapildev, G.; Manickavasagam, M. [Department of Biotechnology and Genetic Engineering, School of Biotechnology, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India); Thajuddin, N. [Department of Microbiology, Bharathidasan University, Tiruchirappalli 620024 (India); Ganapathi, A., E-mail: aganapathi2007@gmail.com [Department of Biotechnology and Genetic Engineering, School of Biotechnology, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India)

    2014-04-01

    Highlights: • Gold nanoparticles (AuNPs) have been synthesized using Podophyllum hexandrum L. • AuNPs induces the oxidative stress to cell death in human cervical carcinoma cells. • It activates the caspase-cascade to cellular death. • It is actively blocks G2/M phase of cell cycle. - Abstract: Current prospect of nanobiotechnology involves in the greener synthesis of nanostructured materials particularly noble metal nanoparticles for various biomedical applications. In this study, biologically (Podophyllum hexandrum L.) synthesized crystalline gold nanoparticles (AuNPs) with the size range between 5 and 35 nm were screened for its anticancereous potential against human cervical carcinoma cells (HeLa). Stoichiometric proportion of the reaction mixture and conditions were optimized to attain stable nanoparticles with narrow size range. Different high throughput techniques like transmission electron microscope (TEM), X-ray diffraction (XRD) and UV–vis spectroscopy were adopted for the physio-chemical characterization of AuNPs. Additionally, Fourier transform infrared spectroscopy (FTIR) study revealed that the water soluble fractions present in the plant extract solely influences the reduction of AuNPs. Sublimely, synthesized AuNPs exhibits an effective in vitro anticancer activity against HeLa cells via induction of cell cycle arrest and DNA damage. Furthermore, it was evidenced that AuNPs treated cells are undergone apoptosis through the activation of caspase cascade which subsequently leads to mitochondrial dysfunction. Thereby, this study proves that biogenic colloidal AuNPs can be developed as a promising drug candidature for human cervical cancer therapy.

  1. Green synthesis of anisotropic gold nanoparticles for photothermal therapy of cancer.

    Science.gov (United States)

    Fazal, Sajid; Jayasree, Aswathy; Sasidharan, Sisini; Koyakutty, Manzoor; Nair, Shantikumar V; Menon, Deepthy

    2014-06-11

    Nanoparticles of varying composition, size, shape, and architecture have been explored for use as photothermal agents in the field of cancer nanomedicine. Among them, gold nanoparticles provide a simple platform for thermal ablation owing to its biocompatibility in vivo. However, the synthesis of such gold nanoparticles exhibiting suitable properties for photothermal activity involves cumbersome routes using toxic chemicals as capping agents, which can cause concerns in vivo. Herein, gold nanoparticles, synthesized using green chemistry routes possessing near-infrared (NIR) absorbance facilitating photothermal therapy, would be a viable alternative. In this study, anisotropic gold nanoparticles were synthesized using an aqueous route with cocoa extract which served both as a reducing and stabilizing agent. The as-prepared gold nanoparticles were subjected to density gradient centrifugation to maximize its NIR absorption in the wavelength range of 800-1000 nm. The particles also showed good biocompatibility when tested in vitro using A431, MDA-MB231, L929, and NIH-3T3 cell lines up to concentrations of 200 μg/mL. Cell death induced in epidermoid carcinoma A431 cells upon irradiation with a femtosecond laser at 800 nm at a low power density of 6 W/cm(2) proved the suitability of green synthesized NIR absorbing anisotropic gold nanoparticles for photothermal ablation of cancer cells. These gold nanoparticles also showed good X-ray contrast when tested using computed tomography (CT), proving their feasibility for use as a contrast agent as well. This is the first report on green synthesized anisotropic and cytocompatible gold nanoparticles without any capping agents and their suitability for photothermal therapy.

  2. Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy

    Science.gov (United States)

    McLaughlin, Mark F.; Woodward, Jonathan; Boll, Rose A.; Wall, Jonathan S.; Rondinone, Adam J.; Kennel, Stephen J.; Mirzadeh, Saed; Robertson, J. David

    2013-01-01

    Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo α-generator targeted radiotherapies can deliver multiple α particles to a receptor site dramatically amplifying the radiation dose delivered to the target. The major challenge with α-generator radiotherapies is that traditional chelating moieties are unable to sequester the radioactive daughters in the bioconjugate which is critical to minimize toxicity to healthy, non-target tissue. The recoil energy of the 225Ac daughters following α decay will sever any metal-ligand bond used to form the bioconjugate. This work demonstrates that an engineered multilayered nanoparticle-antibody conjugate can deliver multiple α radiations and contain the decay daughters of 225Ac while targeting biologically relevant receptors in a female BALB/c mouse model. These multi-shell nanoparticles combine the radiation resistance of lanthanide phosphate to contain 225Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established gold chemistry for attachment of targeting moieties. PMID:23349921

  3. Hydrodynamic fractionation of finite size gold nanoparticle clusters.

    Science.gov (United States)

    Tsai, De-Hao; Cho, Tae Joon; DelRio, Frank W; Taurozzi, Julian; Zachariah, Michael R; Hackley, Vincent A

    2011-06-15

    We demonstrate a high-resolution in situ experimental method for performing simultaneous size classification and characterization of functional gold nanoparticle clusters (GNCs) based on asymmetric-flow field flow fractionation (AFFF). Field emission scanning electron microscopy, atomic force microscopy, multi-angle light scattering (MALS), and in situ ultraviolet-visible optical spectroscopy provide complementary data and imagery confirming the cluster state (e.g., dimer, trimer, tetramer), packing structure, and purity of fractionated populations. An orthogonal analysis of GNC size distributions is obtained using electrospray-differential mobility analysis (ES-DMA). We find a linear correlation between the normalized MALS intensity (measured during AFFF elution) and the corresponding number concentration (measured by ES-DMA), establishing the capacity for AFFF to quantify the absolute number concentration of GNCs. The results and corresponding methodology summarized here provide the proof of concept for general applications involving the formation, isolation, and in situ analysis of both functional and adventitious nanoparticle clusters of finite size. © 2011 American Chemical Society

  4. Gold coated lanthanide phosphate nanoparticles for targeted alpha generator radiotherapy.

    Directory of Open Access Journals (Sweden)

    Mark F McLaughlin

    Full Text Available Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo α-generator targeted radiotherapies can deliver multiple α particles to a receptor site dramatically amplifying the radiation dose delivered to the target. The major challenge with α-generator radiotherapies is that traditional chelating moieties are unable to sequester the radioactive daughters in the bioconjugate which is critical to minimize toxicity to healthy, non-target tissue. The recoil energy of the (225Ac daughters following α decay will sever any metal-ligand bond used to form the bioconjugate. This work demonstrates that an engineered multilayered nanoparticle-antibody conjugate can deliver multiple α radiations and contain the decay daughters of (225Ac while targeting biologically relevant receptors in a female BALB/c mouse model. These multi-shell nanoparticles combine the radiation resistance of lanthanide phosphate to contain (225Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established gold chemistry for attachment of targeting moieties.

  5. Visible luminescence in polyaniline/(gold nanoparticle) composites

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Renata F. S. [Universidade Federal de Pernambuco, Pos-Graduacao em Ciencia de Materiais (Brazil); Andrade, Cesar A. S. [Universidade Federal de Pernambuco, Departamento de Bioquimica (Brazil); Santos, Clecio G. dos [Instituto de Educacao, Ciencia e Tecnologia de Pernambuco (Brazil); Melo, Celso P. de, E-mail: celso@df.ufpe.br [Universidade Federal de Pernambuco, Pos-Graduacao em Ciencia de Materiais (Brazil)

    2013-01-15

    We describe the use of solution chemistry methods to prepare polyaniline/(gold nanoparticles)-PANI/AuNPs-composites as colloidal particles that exhibit an intense green fluorescence after excitation in the ultraviolet region. Measurements of the relative fluorescence quantum yield indicate that the intensity of the observed luminescence of these nanocomposites is a few orders of magnitude higher than the corresponding fluorescence of either the isolated polymer or the pure AuNPs. Hence, cooperative effects between the conducting polymer chains and the metallic particles must dominate the emission behavior of these materials. Transmission electron microscopy reveals the existence of metal nanoparticle aggregates with sizes in the 2-3 nm range dispersed in the polymer matrix. By implementing an experimental planning, we have been able to change the preparation parameters so as to vary in a controlled manner the intensity and the profile of the luminescence spectrum as well as the size and aggregation characteristics of the colloidal particles. We also show that when the pH of the medium is varied, the dielectric properties (such as the degree of conductivity) of the PANI/AuNPs colloidal solutions and the intensity of their luminescence change in a consistent manner. Due to the polycation nature of the doped PANI chains, we suggest that these composites may find interesting applications as fluorescent markers of biologic molecules.

  6. Visible luminescence in polyaniline/(gold nanoparticle) composites

    Science.gov (United States)

    Santos, Renata F. S.; Andrade, Cesar A. S.; dos Santos, Clecio G.; de Melo, Celso P.

    2013-01-01

    We describe the use of solution chemistry methods to prepare polyaniline/(gold nanoparticles)—PANI/AuNPs—composites as colloidal particles that exhibit an intense green fluorescence after excitation in the ultraviolet region. Measurements of the relative fluorescence quantum yield indicate that the intensity of the observed luminescence of these nanocomposites is a few orders of magnitude higher than the corresponding fluorescence of either the isolated polymer or the pure AuNPs. Hence, cooperative effects between the conducting polymer chains and the metallic particles must dominate the emission behavior of these materials. Transmission electron microscopy reveals the existence of metal nanoparticle aggregates with sizes in the 2-3 nm range dispersed in the polymer matrix. By implementing an experimental planning, we have been able to change the preparation parameters so as to vary in a controlled manner the intensity and the profile of the luminescence spectrum as well as the size and aggregation characteristics of the colloidal particles. We also show that when the pH of the medium is varied, the dielectric properties (such as the degree of conductivity) of the PANI/AuNPs colloidal solutions and the intensity of their luminescence change in a consistent manner. Due to the polycation nature of the doped PANI chains, we suggest that these composites may find interesting applications as fluorescent markers of biologic molecules.

  7. Biodirected synthesis and nanostructural characterization of anisotropic gold nanoparticles.

    Science.gov (United States)

    Plascencia-Villa, Germán; Torrente, Daniel; Marucho, Marcelo; José-Yacamán, Miguel

    2015-03-24

    Gold nanoparticles with anisotropic structures have tunable absorption properties and diverse bioapplications as image contrast agents, plasmonics, and therapeutic-diagnostic materials. Amino acids with electrostatically charged side chains possess inner affinity for metal ions. Lysine (Lys) efficiently controlled the growing into star-shape nanoparticles with controlled narrow sizes (30-100 nm) and produced in high yields (85-95%). Anisotropic nanostructures showed tunable absorbance from UV to NIR range, with extraordinary colloidal stability (-26 to -42 mV) and surface-enhanced Raman scattering properties. Advanced electron microscopy characterization through ultra-high-resolution SEM, STEM, and HR-TEM confirmed the size, nanostructure, crystalline structure, and chemical composition. Molecular dynamics simulations revealed that Lys interacted preferentially with Au(I) through the -COOH group instead of their positive side chains with a binding free energy (BFE) of 3.4 kcal mol(-1). These highly monodisperse and colloidal stable anisotropic particles prepared with biocompatible compounds may be employed in biomedical applications.

  8. Hyaluronate coating enhances the delivery and biocompatibility of gold nanoparticles.

    Science.gov (United States)

    Karakocak, Bedia Begum; Liang, Jue; Biswas, Pratim; Ravi, Nathan

    2018-04-15

    For targeted delivery with nanoparticles (NPs) as drug carriers, it is imperative that the NPs are internalized into the targeted cell. Surface properties of NPs influence their interactions with cells. We examined the responses of retinal pigment epithelial cells, NIH 3T3 fibroblast cells, and Chinese hamster ovary cells to gold nanoparticles (Au NPs) in their nascent form as well as coated with end-thiolated hyaluronate (HS-HA). The grafting density of HS-HA on Au NPs was calculated based on total organic carbon measurements and thermal gravimetric analysis. We imaged the intracellular NPs by 3D confocal microscopy. We quantified viability and generation of reactive oxygen species (ROS) of the cells to Au NPs and monitored cell-surface attachment via electrical cell-substrate impedance sensing. The results confirmed that receptors on cell surfaces, for HA, are critical in internalizing HS-HA-Au NPs, and HA may mitigate ROS pathways known to lead to cell death. The 50- and 100-nm HS-HA-Au NPs were able to enter the cells; however, their nascent forms could not. This study shows that the delivery of larger Au NPs is enhanced with HS-HA coating and illustrates the potential of HA-coated NPs as a drug delivery agent for inflamed, proliferating, and cancer cells that express CD44 receptors. Published by Elsevier Ltd.

  9. Behavior of colloidal gold nanoparticles in different ionic strength media

    Science.gov (United States)

    Barreto, Ângela; Luis, Luis G.; Girão, Ana V.; Trindade, Tito; Soares, Amadeu M. V. M.; Oliveira, Miguel

    2015-12-01

    The increased applications of engineered nanoparticles (NPs) may lead to environmental release and transport to estuarine environments where NPs are expected to aggregate/agglomerate with increasing ionic strength. However, more stable NPs that may be resistant to high ionic strength media and more dispersed in the aquatic environment are being synthesized. Thus, understanding colloidal NPs' behavior in different ionic strength media is crucial for the assessment of the consequences of their environmental release. This work assessed the behavior of gold nanoparticles (AuNPs), with diverse sizes and coatings, in media with different ionic strengths (from biological buffers to artificial seawater). Overall, in biological buffers and artificial seawater, citrate-coated AuNPs were unstable, displaying significantly increased sizes (between 100 and 400 nm), whereas no significant alterations (less than 5 % oscillation) were found for AuNPs with other coatings (bovine serum albumin, polyvinylpyrrolidone, and polyethylene glycol). Data suggest that coated AuNPs, and probably other NPs, may be dispersed in the environment from freshwater to estuarine systems.

  10. Effect of gold nanoparticle on stability of the DNA molecule: A study of molecular dynamics simulation.

    Science.gov (United States)

    Izanloo, Cobra

    2017-09-02

    An understanding of the mechanism of DNA interactions with gold nanoparticles is useful in today medicine applications. We have performed a molecular dynamics simulation on a B-DNA duplex (CCTCAGGCCTCC) in the vicinity of a gold nanoparticle with a truncated octahedron structure composed of 201 gold atoms (diameter ∼1.8 nm) to investigate gold nanoparticle (GNP) effects on the stability of DNA. During simulation, the nanoparticle is closed to DNA and phosphate groups direct the particles into the major grooves of the DNA molecule. Because of peeling and untwisting states that are occur at end of DNA, the nucleotide base lies flat on the surface of GNP. The configuration entropy is estimated using the covariance matrix of atom-positional fluctuations for different bases. The results show that when a gold nanoparticle has interaction with DNA, entropy increases. The results of conformational energy and the hydrogen bond numbers for DNA indicated that DNA becomes unstable in the vicinity of a gold nanoparticle. The radial distribution function was calculated for water hydrogen-phosphate oxygen pairs. Almost for all nucleotide, the presence of a nanoparticle around DNA caused water molecules to be released from the DNA duplex and cations were close to the DNA.

  11. Biosynthesis, structural characterization and antimicrobial activity of gold and silver nanoparticles.

    Science.gov (United States)

    Ahmad, Tokeer; Wani, Irshad A; Manzoor, Nikhat; Ahmed, Jahangeer; Asiri, Abdullah M

    2013-07-01

    An eco friendly simple biosynthetic route was used for the preparation of monodisperse and highly crystalline gold and silver nanoparticles using cell free extract of fungus, Candida albicans. Transmission electron microscopic studies show the formation of gold and silver nanocrystals of average size of 5 nm and 30 nm with the specific surface areas of 18.9 m(2)/g and 184.4 m(2)/g respectively. The interaction of gold and silver nanoparticles with proteins has been formulated by FT-IR spectroscopy and thermal gravimetric analysis. The formation of gold and silver nanoparticles was also confirmed by the appearance of a surface plasmon band at 540 nm and 450 nm respectively. The antimicrobial activity of the synthesized gold and silver nanoparticles was investigated against both Staphylococcus aureus and Escherichia coli. The results suggest that these nanoparticles can be used as effective growth inhibitors against the test microorganisms. Greater bactericidal activity was observed for silver nanoparticles. The E. coli, a gram negative bacterium was found to be more susceptible to gold and silver nanoparticles than the S. aureus, a gram positive bacterium. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Characterization and antimicrobial application of biosynthesized gold and silver nanoparticles by using Microbacterium resistens.

    Science.gov (United States)

    Wang, Chao; Singh, Priyanka; Kim, Yeon Ju; Mathiyalagan, Ramya; Myagmarjav, Davaajargal; Wang, Dandan; Jin, Chi-Gyu; Yang, Deok Chun

    2016-11-01

    Various microorganisms were found to be cable of synthesizing gold and silver nanoparticles when gold and silver salts were supplied in the reaction system. The main objective of this study was to evaluate the extracellular synthesis of gold and silver nanoparticles by the type strain Microbacterium resistens(T) [KACC14505]. The biosynthesized gold and silver nanoparticles were characterized by ultraviolet-visible spectroscopy (UV-Vis), field emission transmission electron micrograph (FE-TEM), energy dispersive X-ray spectroscopy (EDX), elemental mapping, and dynamic light scattering (DLS). Moreover, the nanoparticles were evaluated for antimicrobial potential against various pathogenic microorganisms such as Vibrio parahaemolyticus [ATCC 33844], Salmonella enterica [ATCC 13076], Staphylococcus aureus [ATCC 6538], Bacillus anthracis [NCTC 10340], Bacillus cereus [ATCC 14579], Escherichia coli [ATCC 10798], and Candida albicans [KACC 30062]. The silver nanoparticles were found as a potent antimicrobial agent whereas gold nanoparticles not showed any ability. Therefore, the current study describes the simple, green, and extracellular synthesis of gold and silver nanoparticles by the type strain Microbacterium resistens(T) [KACC14505].

  13. Distance dependent fluorescence quenching and enhancement of gold nanoclusters by gold nanoparticles.

    Science.gov (United States)

    Qin, Haiyan; Ma, Diao; Du, Jianxiu

    2018-01-15

    The interaction between fluorescent gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) has been investigated. It was observed that the fluorescence of AuNCs was remarkably quenched when direct contact with AuNPs. The fluorescence quenching of AuNCs by AuNPs was dynamic quenching and exhibited size-dependent property. A larger size of AuNPs displayed a stronger quenching effect and gave a larger quenching constant. When a silica spacer shell was introduced between AuNPs and AuNCs, a fluorescence enhancement of AuNCs by Au@SiO2 NPs was observed. The fluorescence enhancement was strongly dependent on the separation distance between the AuNPs and the AuNCs. A maximal enhancement of 3.72 times was observed when Au@SiO2 NPs have a silica shell thickness of 12nm. This nanocomposite consisting of relatively nontoxic AuNPs and AuNCs may have a potential application in developing novel fluorescent sensor. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Biosynthesis and Characterization of Gold and Silver Nanoparticles Using Milk Thistle (Silybum marianum Seed Extract

    Directory of Open Access Journals (Sweden)

    R. Gopalakrishnan

    2014-01-01

    Full Text Available Biogenic synthesis of gold and silver nanoparticles from aqueous solutions using milk thistle (Silybum marianum seed extract as reducing and stabilizing agent has been reported. Formation and stabilization of nanoparticles were monitored using surface plasmon resonance (SPR bands of UV-Vis spectroscopy. Morphology of gold and silver nanoparticles was investigated using X-ray diffraction, high-resolution transmission electron microscopy with selected area electron diffraction analysis, and dynamic light scattering. Fourier transform-infrared spectroscopy was employed to identify the possible biomolecules responsible for the reduction and stabilization of nanoparticles.

  15. Photoisomerization of azobenzene derivatives confined in gold nanoparticle aggregates.

    Science.gov (United States)

    Yoon, Jun Hee; Yoon, Sangwoon

    2011-07-28

    Photoisomerization is an important reaction that confers photoresponsive functionality on nanoparticles. Although photoisomerization of molecules forming self-assembled monolayers on two-dimensional surfaces or three-dimensional clusters has been studied, a detailed picture of interactions of molecules undergoing isomerization with nanoparticles is not available. In this paper, we report on the photoisomerization of azobenzene derivatives spatially confined in gold nanoparticle (AuNP) aggregates. AuNP aggregates allow us to simultaneously probe the structural changes of molecules via surface-enhanced Raman spectroscopy (SERS) and the accompanying changes in interparticle interactions via surface plasmon couplings. AuNP aggregates are formed by the adsorption of synthesized azobenzene-derivatized sulfides (Az) onto the surfaces of AuNPs. The photoisomerization of the adsorbed Az from trans to cis by excitation at 365 nm causes the AuNPs to move close to each other in the aggregates, leading to a redshift of the surface plasmon coupling band in the UV-vis spectra and a concomitant rise in SERS intensity. SERS spectra reveal that the vibrational modes containing the N=N stretching character redshift upon irradiation, suggesting that the N=N bond is significantly weakened when Az is in the cis form in the AuNP aggregates. The weakening of the N=N bond is attributed to the interaction of the N=N bond, which is more exposed to the outside in the cis conformation, with the nearby AuNPs that have come closer by the isomerization of adsorbed Az. We find that backisomerization from cis to trans occurs much faster in the AuNP aggregates (k = 1.9 × 10(-2) min(-1)) than in solution (k = 1.3 × 10(-3) min(-1)) because of the reduced N=N bond order of cis-Az in the aggregates. This journal is © the Owner Societies 2011

  16. Synthesis of gold nanoparticles from different cellular fractions of Fusarium oxysporum.

    Science.gov (United States)

    Deepa, Kannan; Panda, Tapobrata

    2014-05-01

    The addition of varying concentrations of precursor gold salt to different cellular fractions of Fusarium oxysporum, viz., the culture filtrate and the intracellular extract obtained in the growing and resting phase of the cells had a profound influence on the size, shape, and state of aggregation of the nanoparticles. Multiply-twinned nanoparticles were obtained when the culture filtrate was used for synthesizing nanoparticles while mostly irregular shapes were obtained with the intracellular extract. The time taken for the formation of gold nanoparticles in the culture filtrate of resting cells was very less (synthesis of nanoparticles. There was a reduction in size of the nanoparticles with decreasing concentration of the gold salt from 1 mM to 0.05 mM. With the intracellular extract, the initial rate of increase in surface plasmon absorption maximum was linearly proportional to the initial concentration of the gold salt used. Gold nanoparticles were also obtained with the heat-inactivated culture filtrate which suggests alternatively the role of peptides and amino acids besides proteins in reducing and/or stabilizing the nanoparticles.

  17. Implementing atomic force microscopy (AFM) for studying kinetics of gold nanoparticle's growth

    DEFF Research Database (Denmark)

    Georgiev, P.; Bojinova, A.; Kostova, B.

    2013-01-01

    In a novel experimental approach Atomic Force Microscopy (AFM) was applied as a tool for studying the kinetics of gold nanoparticle growth. The gold nanoparticles were obtained by classical Turkevich citrate synthesis at two different temperatures. From the analysis of AFM images during the synth......In a novel experimental approach Atomic Force Microscopy (AFM) was applied as a tool for studying the kinetics of gold nanoparticle growth. The gold nanoparticles were obtained by classical Turkevich citrate synthesis at two different temperatures. From the analysis of AFM images during...... approach. We also compared AFM experimental data with Dynamic Light Scattering (DLS) and with Transmission Electron Microscopy (TEM) data. The experimental data from all the applied methods were fitted with two step Finke-Watzky kinetics model and the corresponding kinetics constants were obtained...

  18. Magnetic gold nanoparticle-mediated small interference RNA silencing Bag-1 gene for colon cancer therapy

    National Research Council Canada - National Science Library

    HUANG, WENBAI; LIU, ZHAN'AO; ZHOU, GUANZHOU; TIAN, AILING; SUN, NIANFENG

    ... function of colon cancer. We prepared and evaluated magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex, a gene therapy system, which can transfect cells efficiently, for both therapeutic effect and safety...

  19. Gold Nanoparticles: An Efficient Antimicrobial Agent against Enteric Bacterial Human Pathogen

    Science.gov (United States)

    Shamaila, Shahzadi; Zafar, Noshin; Riaz, Saira; Sharif, Rehana; Nazir, Jawad; Naseem, Shahzad

    2016-01-01

    Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent. Ultra Violet (UV)-visible spectroscopy revealed the size of chemically synthesized gold nanoparticle as 6–40 nm. Atomic force microscopy (AFM) analysis confirmed the size and X-ray diffractometry (XRD) analysis determined the polycrystalline nature of gold nanoparticles. The present findings explained how gold nanoparticles lyse Gram-negative and Gram-positive bacteria. PMID:28335198

  20. Mono- and bi-functional arenethiols as surfactants for gold nanoparticles: synthesis and characterization

    National Research Council Canada - National Science Library

    Vitale, Floriana; Fratoddi, Ilaria; Battocchio, Chiara; Piscopiello, Emanuela; Tapfer, Leander; Russo, Maria Vittoria; Polzonetti, Giovanni; Giannini, Cinzia

    2011-01-01

    Stable gold nanoparticles stabilized by different mono and bi-functional arenethiols, namely, benzylthiol and 1,4-benzenedimethanethiol, have been prepared by using a modified Brust's two-phase synthesis...

  1. Mono- and bi-functional arenethiols as surfactants for gold nanoparticles: synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Fratoddi Ilaria

    2011-01-01

    Full Text Available Abstract Stable gold nanoparticles stabilized by different mono and bi-functional arenethiols, namely, benzylthiol and 1,4-benzenedimethanethiol, have been prepared by using a modified Brust's two-phase synthesis. The size, shape, and crystalline structure of the gold nanoparticles have been determined by high-resolution electron microscopy and full-pattern X-ray powder diffraction analyses. Nanocrystals diameters have been tuned in the range 2 ÷ 9 nm by a proper variation of Au/S molar ratio. The chemical composition of gold nanoparticles and their interaction with thiols have been investigated by X-ray photoelectron spectroscopy. In particular, the formation of networks has been observed with interconnected gold nanoparticles containing 1,4-benzenedimethanethiol as ligand.

  2. Ship-in-bottle synthesis of gold nanoparticles in amino-functionalized mesoporous silica thin films.

    Science.gov (United States)

    Fang, Jingyue; Qin, Shiqiao; Zhang, Xueao; Wang, Fei

    2013-04-01

    Amino-functionalized mesoporous silica thin films with high content of -NH2 moieties have been directly dip-coated on silicon wafers by co-condensation of tetraethoxysilane and 3-aminopropyltriethoxysilane in the presence of C16H33(OCH2CH2)10OH under acidic condition. X-ray diffraction patterns show that it is a good strategy to remove the surfactant by ethanol extraction rather than calcinations. Using the amino-functionalized mesoporous silica thin films as templates, nanoparticles arrays of gold are formed well within the mesostructures. The isolated gold nanoparticles with size of 2.4-3.9 nm are released by dissolving the silica frameworks with the help of an ethanol solution of HF, showing that the gold nanoparticles have uniform size and spherical appearance. The Ultraviolet-visible spectra show that as the size of gold nanoparticles increase when the dipping time extended, the surface plasmon resonance absorption peak shifts to a longer wavelength.

  3. Efficient light extraction from GaN LEDs using gold-coated ZnO nanoparticles

    KAUST Repository

    Alhadidi, A.

    2015-11-01

    We experimentally demonstrate the effect of depositing gold-coated ZnO nanoparticles on the surface of GaN multi-quantum well LED structures. We show that this method can significantly increase the amount of extracted light.

  4. Spherical gold nanoparticles and gold nanorods for the determination of gentamicin

    Science.gov (United States)

    Miranda-Andrades, Jarol R.; Pérez-Gramatges, Aurora; Pandoli, Omar; Romani, Eric C.; Aucélio, Ricardo Q.; da Silva, Andrea R.

    2017-02-01

    Gentamicin is an antibiotic indicated to treat mastitis in dairy cattle and for the treatment of bacterial resistance in the context of hospital infections. The effect caused by gentamicin on the optical properties of gold nanoparticles aqueous dispersions were used to develop quantitative methods to determine this antibiotic. Two different aqueous dispersions, one containing spherical Au nanoparticles (AuNPs) and the other containing Au nanorods (AuNRs), had their conditions adjusted to enable a stable and sensitive response towards gentamicin. The use of AuNPs, with measurement at 681 nm of the rising coupling plasmon band, enabled a limit of detection (LOD) of 0.4 ng mL- 1 (0.02 ng absolute LOD), ten times lower than the one achieved by measuring the decreasing of the longitudinal surface plasmon resonance band (at 662 nm). The linear analytical response of AuNPs measured at 681 nm did not require rationing of signal values to correct for linearity. Stability of the analytical response resulted in intermediary precision below 2%. No significant interference was imposed by excipients traditionally present in injectable solutions for veterinary use. Percent recoveries obtained in such formulations were between 94.5 and 98.2% regardless the existence of any difference in the proportion of the compounds known as gentamicin (C1, C1a and C2) in standard and in the samples. The method requires no derivatization with toxic reagents as usually is required in other spectroscopic approaches.

  5. Synthesis and characterization of thiolated pectin stabilized gold coated magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Varun, E-mail: varun.arora3986@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Sector 16-C, Dwarka, New Delhi 110078 (India); Sood, Ankur, E-mail: ankursood02@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Sector 16-C, Dwarka, New Delhi 110078 (India); Shah, Jyoti, E-mail: shah.jyoti1@gmail.com [National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Kotnala, R.K., E-mail: rkkotnala@nplindia.org [National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Jain, Tapan K., E-mail: tapankjain@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Sector 16-C, Dwarka, New Delhi 110078 (India)

    2016-04-15

    Core–shell nanoparticles, magnetic core and gold shell, were synthesized by reduction of gold chloride on the surface of magnetic nanoparticles; using tyrosine as a reducing agent. The formation of gold shell on magnetic nanoparticles was confirmed by X-ray diffraction (XRD) and UV-Visible spectroscopy. The core–shell nanoparticles (CSn) were conjugated with thiolated pectin to form a stable aqueous dispersion. The hydrodynamic size of thiolated pectin stabilized core–shell nanoparticles (TP-CSn) measured by Dynamic light scattering (DLS) was 160.5 nm with a poly dispersity index (PDI) of 0.302, whereas the mean particle size of TP-CSn calculated by high resolution transmission electron microscopy (HRTEM) was 10.8 ± 2.7 nm. The value of zeta potential for TP-CSn was −13.6 mV. There was a decrease in the value of saturation magnetization upon formation of the gold shell on magnetic nanoparticles. The amount of thiolated pectin bound to the surface of core–shell nanoparticles, calculated using Thermogravimetric analysis (TGA), was 6% of sample weight. - Highlights: • Use of side group of tyrosine (phenol) as a pH dependent reducing agent to synthesize gold coated magnetic nanoparticles. • Successful coating of gold shell on magnetic nanoparticles core. • Synthesis of thiolated pectin and stabilization of aqueous dispersion of core–shell nanoparticles with thiolated pectin. • The superparamagnetic behaviour of magnetic nanoparticles is retained after shell formation.

  6. A strategic approach for rapid synthesis of gold and silver nanoparticles by Panax ginseng leaves.

    Science.gov (United States)

    Singh, Priyanka; Kim, Yeon Ju; Yang, Deok Chun

    2016-12-01

    The study highlights the synthesis of gold nanoparticles and silver nanoparticles by fresh leaves of Panax ginseng, an herbal medicinal plant. The reduction of auric chloride and silver nitrate led to the formation of gold and silver nanoparticles within 3 and 45 min, at 80°C, respectively. The developed methodology was rapid, facile, ecofriendly and the utmost significant is quite economical, which did not require subsequent processing for reduction or stabilization of nanoparticles. The nanoparticles were further characterized by Ultraviolet-visible spectroscopy (UV-vis) which showed the relevant peak for gold and silver nanoparticles at 578 and 420 nm, correspondingly. Field-emission transmission electron microscopy (FE-TEM) displayed the spherical shape of monodispersed nanoparticles. FE-TEM revealed that the gold nanoparticles were 10-20 nm and silver nanoparticles were 5-15 nm. The energy dispersive X-ray (EDX) and elemental mapping results indicated the maximum distribution of gold and silver elements in the respective nanoproducts, which further corresponds the purity. Further, the X-ray diffraction (XRD) results confirm the crystalline nature of synthesized nanoparticles. The biosynthesized AgNPs served as an efficient antimicrobial agent at 3 μg concentration against many pathogenic strains for instance, Escherichia coli, Salmonella enterica, Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus anthracis and Bacillus cereus. In addition, AgNPs showed complete inhibition of biofilm formation by S. aureus and Pseudomonas aeruginosa at 4 μg/ml concentration. Moreover, the AuNPs and AgNPs found as a potent anticoagulant agent. Thus, the study claims the rapid synthesis of gold and silver nanoparticles by fresh P. ginseng leaf extract and its biological applications.

  7. Investigation of the complex structure, comparative DNA-binding and DNA cleavage of two water-soluble mono-nuclear lanthanum(III) complexes and cytotoxic activity of chitosan-coated magnetic nanoparticles as drug delivery for the complexes

    Science.gov (United States)

    Asadi, Zahra; Nasrollahi, Neda; Karbalaei-Heidari, Hamidreza; Eigner, Vaclav; Dusek, Michal; Mobaraki, Nabiallah; Pournejati, Roya

    2017-05-01

    Two water-soluble mono-nuclear macrocyclic lanthanum(III) complexes of 2,6-diformyl-4-methylphenol with 1,3-diamino-2-propanol (C1) or 1,3-propylenediamine (C2) were synthesized and characterized by UV-Vis, FT-IR, 13C and 1H NMR spectroscopy and elemental analysis. C1 complex was structurally characterized by single-crystal X-ray diffraction, which revealed that the complex was mononuclear and ten-coordinated. The coordination sites around lanthanum(III) were occupied with a five-dentate ligand, two bidentate nitrates, and one water molecule. The interaction of complexes with DNA was studied in buffered aqueous solution at pH 7.4. UV-Vis absorption spectroscopy, emission spectroscopy, circular dichroism (CD) and viscometric measurements provided clear evidence of the intercalation mechanism of binding. The obtained intrinsic binding constants (Kb) 9.3 × 103 and 1.2 × 103 M- 1 for C1 and C2, respectively confirmed that C1 is better intercalator than C2. The DNA docking studies suggested that the complexes bind with DNA in a groove binding mode with the binding affinity of C1 > C2. Moreover, agarose gel electrophoresis study of the DNA-complex for both compounds revealed that the C1 intercalation cause ethidium bromide replacement in a competitive manner which confirms the suggested mechanism of binding. Finally, the anticancer experiments for the treated cancerous cell lines with both synthesized compounds show that these hydrophilic molecules need a suitable carrier to pass through the hydrophobic nature of cell membrane efficiently.

  8. Toxicological risk assessment of elemental gold following oral exposure to sheets and nanoparticles – A review

    DEFF Research Database (Denmark)

    Hadrup, Niels; Sharma, Anoop Kumar; Poulsen, Morten

    2015-01-01

    of gold ions from its surface. Elemental gold, or the released ions, is, to some extent, absorbed in the gastrointestinal tract. Gold is distributed to organs such as the liver, heart, kidneys and lungs. The main excretion route of absorbed gold is through urine. Data on the oral toxicity of elemental...... gold is limited. The acute toxicity of elemental gold seems to be low, as rats were unaffected by a single dose of 2000mg nanoparticles/kg of body weight. Information on repeated dose toxicity is very limited. Skin rashes have been reported in humans following the ingestion of liquors containing gold...... melanogaster; however, genotoxicity studies in mammals are lacking. Overall, based on the literature and taking low human exposure into account, elemental gold via the oral route is not considered to pose a health concern to humans in general....

  9. Synthesis and Evaluation of Paclitaxel-Loaded Gold Nanoparticles for Tumor-Targeted Drug Delivery.

    Science.gov (United States)

    Paciotti, Giulio F; Zhao, Jielu; Cao, Shugeng; Brodie, Peggy J; Tamarkin, Lawrence; Huhta, Marja; Myer, Lonnie D; Friedman, Jay; Kingston, David G I

    2016-11-16

    The synthesis of a series of thiolated paclitaxel analogs is described as part of a novel nanomedicine program aimed at developing formulations of paclitaxel that will bind to gold nanoparticles for tumor targeted drug delivery. Preliminary evaluation of the new nanomedicine composed of 27 nm gold nanoparticles, tumor necrosis factor alpha (TNFα), thiolated polyethylene glycol (PEG-thiol), and one of several thiolated paclitaxel analogs is presented.

  10. Charge storage ability of the gold nanoparticles: Towards the performance of a supercapacitor

    Science.gov (United States)

    Choudhary, Meenakshi; Siwal, Samarjeet; Nandi, Debkumar; Mallick, Kaushik

    2017-12-01

    Polymer supported gold nanoparticles has been synthesized using a single-step route, from the corresponding monomer and metal salt precursors, and was analysed by means of optical, microscopic and surface characterization techniques. The metal-polymer supramolecular complex in combination with reduced graphene oxide form a 'hybrid architecture' and display the property of an electrochemical supercapacitor where the gold nanoparticles have a prevailing role as the charge storage component within the system.

  11. Gold nanoparticle catalyzed oxidation of alcohols - From biomass to commodity chemicals

    DEFF Research Database (Denmark)

    Taarning, Esben; Christensen, Claus H.

    2007-01-01

    and glycerol are rich in alcohol functionalities. Thus, a key step in utilizing these resources lies in the conversion of this functional group. Benign oxidations involving oxygen as the stoichiometric oxidant are important from both an environmental and economical perspective. Recently, it has become clear...... that supported gold nanoparticles are highly active catalysts for oxidizing alcohols and aldehydes using oxygen as the oxidant. This perspective will focus on the use of gold nanoparticles in the oxidation of renewables....

  12. Tryptophan-functionalized gold nanoparticles for deep UV imaging of microbial cells.

    Science.gov (United States)

    Pajović, Jelena D; Dojčilović, Radovan; Božanić, Dušan K; Kaščáková, Slavka; Réfrégiers, Matthieu; Dimitrijević-Branković, Suzana; Vodnik, Vesna V; Milosavljević, Aleksandar R; Piscopiello, Emanuela; Luyt, Adriaan S; Djoković, Vladimir

    2015-11-01

    Biocompatible fluorescent nanostructures were prepared by a functionalization of gold nanoparticles with the amino acid tryptophan. The gold-tryptophan bioconjugates were investigated by TEM and HRTEM and various spectroscopy methods (XPS, FTIR, UV-vis and photoluminescence). It was found that the gold nanoparticles, initially 8 nm in diameter, aggregate in the presence of the amino acid. From the XPS and FTIR spectroscopy results, it was concluded that the tryptophan gold interactions mainly take place via indole and carboxyl groups. Although the indole group is involved in the interaction with the gold surfaces, the tryptophan-gold hybrids showed strong fluorescence due to the presence of multilayers of tryptophan. Deep ultra violet (DUV) imaging performed at the SOLEIL synchrotron showed that it is possible to detect these hybrid nanostructures within Escherichia coli cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Comparative study of gum arabic and PVP as stabilizing agents for synthesis of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Andressa A.; Leal, Jessica; Geraldes, Adriana N.; Lugao, Ademar B., E-mail: andressa_alvess@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Use Colloidal metallic nanoparticles such as gold nanoparticles have received a great attention, due in part to their specific properties and potential applications. Control of size and uniformity of nanoparticles is important to prevent aggregation. High-molecular-weight polymers were used as stabilizer agents. Natural polymers, such as gum Arabic, are used as stabilizer because of capping nanoparticles behavior and present advantages such as solubility, non- toxicity and its compatibility for pharmaceutical and biomedical applications. Previous studies showed that the hydrophilic group of Poly(vinyl pyrrolidone) (PVP) caused repulsion on gold nanoparticles surface because steric interactions with polymer, for this reason this kind of polymers could be used as stabilizer agent. The aim of this work is to study the synthesis and stabilization of gold nanoparticles with PVP and gum Arabic using gamma radiation. The results obtained by samples analysis using UV-Visible showed that the gamma irradiation doses influenced the nanoparticles formation by PVP but that is not the case with the GA, because for smaller quantity of Arabic gum in different doses produced and stabilized nanoparticles. The samples were observed for 20 days and showed stability. We have obtained preliminary results showed that the use of radiation is applicable to the formation of gold nanoparticles. (author)

  14. NON-INVASIVE RADIOFREQUENCY ABLATION OF CANCER TARGETED BY GOLD NANOPARTICLES

    Science.gov (United States)

    Cardinal, Jon; Klune, John Robert; Chory, Eamon; Jeyabalan, Geetha; Kanzius, John S.; Nalesnik, Michael; Geller, David A.

    2008-01-01

    Introduction Current radiofrequency ablation (RFA) techniques require invasive needle placement and are limited by accuracy of targeting. The purpose of this study was to test a novel non-invasive radiowave machine that uses RF energy to thermally destroy tissue. Gold nanoparticles were designed and produced to facilitate tissue heating by the radiowaves. Methods A solid state radiowave machine consisting of a power generator and transmitting/receiving couplers which transmit radiowaves at 13.56 MHz was used. Gold nanoparticles were produced by citrate reduction and exposed to the RF field either in solutions testing or after incubation with HepG2 cells. A rat hepatoma model using JM-1 cells and Fisher rats was employed using direct injection of nanoparticles into the tumor to focus the radiowaves for select heating. Temperatures were measured using a fiber-optic thermometer for real-time data. Results Solutions containing gold nanoparticles heated in a time- and power-dependent manner. HepG2 liver cancer cells cultured in the presence of gold nanoparticles achieved adequate heating to cause cell death upon exposure to the RF field with no cytotoxicity attributable to the gold nanoparticles themselves. In vivo rat exposures at 35W using gold nanoparticles for tissue injection resulted in significant temperature increases and thermal injury at subcutaneous injection sites as compared to vehicle (water) injected controls. Discussion These data show that non-invasive radiowave thermal ablation of cancer cells is feasible when facilitated by gold nanoparticles. Future studies will focus on tumor selective targeting of nanoparticles for in vivo tumor destruction. PMID:18656617

  15. Synthesis and characterization of genistein conjugated with gold nanoparticles and the study of their cytotoxic properties.

    Science.gov (United States)

    Stolarczyk, Elżbieta U; Stolarczyk, Krzysztof; Łaszcz, Marta; Kubiszewski, Marek; Maruszak, Wioleta; Olejarz, Wioletta; Bryk, Dorota

    2017-01-01

    Gold nanoparticles conjugated with drug substances are used in diagnostics and therapies. Apart from the combinations involving gold nanoparticles conjugated with drug substances through linkers, a direct bonding is also known. In our paper the example of such a direct bonding between gold nanoparticles and genistein (AuNPs-GE) is presented. This conjugate was obtained in a one-pot synthesis and the formation of AuNPs-GE was monitored in terms of color change and UV-Vis spectroscopy. It has been shown that genistein reduces Au3+ ions to spherical Au0 nanocrystallites and acts as a stabilizing agent. The efficiency of the purification of the conjugate from free genistein was controlled by the capillary electrophoresis. Gold nanoparticles are homogeneously shaped and have a narrow range of size from 14 to 33nm and the size of the nanoparticles modified with genistein is around 64.64±0.41nm, as measured by the TEM and DSL techniques, respectively. The zeta potential of the gold nanoparticles modified with genistein is -19.32±0.82mV and suggests a high stability of the nanoparticles and lower toxicity for the normal cells. The identity of genistein on the gold nanoparticles was proved by the electrochemistry, NMR and Raman spectroscopy. The mechanism of the conjugate forming has been proposed. The coverage of gold nanoparticles with genistein 5.09% (m/m) has been calculated from the TGA analysis. Moreover, it has been proved that the obtained conjugate is characterized by a high cytotoxic activity towards cancer cells, as observed in the cell line test. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Gold nanoparticles synthesized by gamma radiation and stabilized by bovine serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Jessica; Silva, Andressa A.; Geraldes, Adriana N.; Lugao, Ademar B., E-mail: jessicaleal@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Grasselli, Mariano, E-mail: mariano.grasselli@gmail.com [Departamento de Ciencia y Tecnologia, Universidad Nacional de Quilmes, Bernal (Argentina)

    2015-07-01

    Gold nanoparticles (AuNPs) are a new option for pharmaceutical and cosmetic industries due to their interesting chemical, electrical and catalytic properties. Research for cancer treatments have been developed using this promising radiotherapy agent. The challenge of gold nanoparticles is to keep them stable, due to metallic behavior. It is know that surface plasma resonance promotes agglomeration of metallic nanoparticles, but they are not stable. Stabilizers have been used to reduce agglomeration. The aim of this work is reduction of HAuCl{sub 4} salt to AuNPs performed by gamma radiation {sup 60}Co source and the stabilization of gold nanoparticles using bovine serum albumin (BSA) fraction V as stabilizer agent. AuNPs were characterized by UV-visible to verify the nanoparticles formation. Samples containing BSA and samples obtained by the conventional method (without stabilizer) were monitored for two weeks and analyzed. Results were compared. (author)

  17. Preparation of surfactant-stabilized gold nanoparticle-peptide nucleic acid conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Duy, Janice, E-mail: janice.duy@umit.maine.ed [University of Maine, Graduate School of Biomedical Sciences (United States); Connell, Laurie B. [University of Maine, School of Marine Sciences (United States); Eck, Wolfgang [University of Heidelberg, Applied Physical Chemistry (Germany); Collins, Scott D. [University of Maine, Department of Chemistry (United States); Smith, Rosemary L. [University of Maine, Electrical and Computer Engineering Department (United States)

    2010-09-15

    A simple, two-step method of producing stable and functional peptide nucleic acid (PNA)-conjugated gold nanoparticles using a surfactant stabilization step is presented. PNA are DNA analogs with superior chemical stability and target discrimination, but their use in metallic nanoparticle systems has been limited by the difficulty of producing stable colloids of nanoparticle-PNA conjugates. In this work, the nonionic surfactant Tween 20 (polyoxyethylene (20) sorbitan monolaurate) was used to sterically shield gold surfaces prior to the addition of thiolated PNA, producing conjugates which remain dispersed in solution and retain the ability to hybridize to complementary nucleic acid sequences. The conjugates were characterized using transmission electron microscopy, dynamic light scattering, and UV-visible absorbance spectroscopy. PNA attachment to gold nanoparticles was confirmed with an enzyme-linked immunoassay, while the ability of nanoparticle-bound PNA to hybridize to its complement was demonstrated using labeled DNA.

  18. Efficient Production of Hydrogen from Decomposition of Formic Acid over Zeolite Incorporated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Gallas-Hulin, Agata; Mielby, Jerrik Jørgen; Kegnæs, Søren

    2016-01-01

    Formic acid has a great potential as a safe and convenient source of hydrogen for sustainable chemical synthesis and renewable energy storage. Here, we report a heterogeneous gold nanoparticles catalyst for efficient production of hydrogen from vapor phase decomposition of formic acid using zeolite...... incorporated gold nanoparticles. The catalyst is prepared by pressure assisted impregnation and reduction (PAIR), which results in a uniform distribution of small gold nanoparticles that are incorporated into zeolite silicalite-1 crystals. Consequently, the incorporated nanoparticles exhibit increased...... sintering stability. Based on these results, we believe that incorporation of metal nanoparticles in zeolites may find use as highly active and selective heterogeneous catalysts for the production of hydrogen in future renewable energy applications....

  19. Fabrication of rice-like gold nanoparticles and application in surface-enhanced Raman scattering.

    Science.gov (United States)

    Liu, Bing; Ma, Zhanfang; Li, Kai

    2011-04-01

    A simple method for the synthesis of rice-like gold nanoparticles using gold nanorods (GNRs) as precursors in the aqueous phase was exploited. The method used in this work involves eroding GNRs with potassium ferricyanide in the aqueous phase. Surface plasmon resonance (SPR) bands of the resulting nanoparticles present a notable blue-shift from 670 to 570 nm with increasing amounts of potassium ferricyanide, and subsequently the shape of the resulting nanoparticles can be readily controlled. Most importantly, the SPR response is an almost linear function of the quantity of potassium ferricyanide added. The synthesis of the resulting nanoparticles with various aspect ratios has been extensively studied and is well established. The surface-enhanced Raman scattering (SERS) intensity enhancement of the adsorbate on the surface of these gold nanoparticles was also studied.

  20. Gold Nanoparticles: Synthesis, Stability Test, and Application for the Rice Growth

    Directory of Open Access Journals (Sweden)

    Aiwu Wang

    2014-01-01

    Full Text Available In today’s science, with the use of nanotechnology, nanomaterials, which behave very differently from the bulk solid, can be made. One of the capable uses of nanomaterials is bioapplications which make good use of the specific properties of nanoparticles. However, since the nanoparticles will be used both in-vivo and in-vitro, their stability is an important issue to the scientists, concern. In this dissertation, we are going to test the stability of gold nanoparticles in a number of media including the biocompatible medium and their behaviors will be illustrated in terms of optical properties change and aggregation degree. Herein, we report the synthesis of gold nanoparticles of different shapes and applications for the rice growth with significant difference. The gold nanoparticles can inhibit the elongation of rice root without inhibiting the germination of rice seeds.

  1. Preparation of gold nanoparticles and determination of their particles size via different methods

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad; Usanase, Gisele [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France); Oulmi, Kafia; Aberkane, Fairouz; Bendaikha, Tahar [Laboratory of Chemistry and Environmental Chemistry(LCCE), Faculty of Science, Material Science Department, University of Batna, 05000 (Algeria); Fessi, Hatem [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France); Zine, Nadia [Institut des Sciences Analytiques (ISA), Université Lyon, Université Claude Bernard Lyon-1, UMR-5180, 5 rue de la Doua, F-69100 Villeurbanne (France); Agusti, Géraldine [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France); Errachid, El-Salhi [Institut des Sciences Analytiques (ISA), Université Lyon, Université Claude Bernard Lyon-1, UMR-5180, 5 rue de la Doua, F-69100 Villeurbanne (France); Elaissari, Abdelhamid, E-mail: elaissari@lagep.univ-lyon1.fr [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France)

    2016-07-15

    Graphical abstract: Preparation of gold nanoparticles via NaBH{sub 4} reduction method, and determination of their particle size, size distribution and morphology by using different techniques. - Highlights: • Gold nanoparticles were synthesized by NaBH{sub 4} reduction method. • Excess of reducing agent leads to tendency of aggregation. • The particle size, size distribution and morphology were investigated. • Particle size was determined both experimentally as well as theoretically. - Abstract: Gold nanoparticles have been used in various applications covering both electronics, biosensors, in vivo biomedical imaging and in vitro biomedical diagnosis. As a general requirement, gold nanoparticles should be prepared in large scale, easy to be functionalized by chemical compound of by specific ligands or biomolecules. In this study, gold nanoparticles were prepared by using different concentrations of reducing agent (NaBH{sub 4}) in various formulations and their effect on the particle size, size distribution and morphology was investigated. Moreover, special attention has been dedicated to comparison of particles size measured by various techniques, such as, light scattering, transmission electron microscopy, UV spectrum using standard curve and particles size calculated by using Mie theory and UV spectrum of gold nanoparticles dispersion. Particle size determined by various techniques can be correlated for monodispersed particles and excess of reducing agent leads to increase in the particle size.

  2. Characterization of citrate capped gold nanoparticle-quercetin complex: Experimental and quantum chemical approach

    Science.gov (United States)

    Pal, Rajat; Panigrahi, Swati; Bhattacharyya, Dhananjay; Chakraborti, Abhay Sankar

    2013-08-01

    Quercetin and several other bioflavonoids possess antioxidant property. These biomolecules can reduce the diabetic complications, but metabolize very easily in the body. Nanoparticle-mediated delivery of a flavonoid may further increase its efficacy. Gold nanoparticle is used by different groups as vehicle for drug delivery, as it is least toxic to human body. Prior to search for the enhanced efficacy, the gold nanoparticle-flavonoid complex should be prepared and well characterized. In this article, we report the interaction of gold nanoparticle with quercetin. The interaction is confirmed by different biophysical techniques, such as Scanning Electron Microscope (SEM), Circular Dichroism (CD), Fourier-Transform InfraRed (FT-IR) spectroscopy and Thermal Gravimetric Analysis (TGA) and cross checked by quantum chemical calculations. These studies indicate that gold clusters are covered by citrate groups, which are hydrogen bonded to the quercetin molecules in the complex. We have also provided evidences how capping is important in stabilizing the gold nanoparticle and further enhances its interaction with other molecules, such as drugs. Our finding also suggests that gold nanoparticle-quercetin complex can pass through the membranes of human red blood cells.

  3. Fabrication of gold and silver nanoparticles with pulsed laser ablation under pressurized CO2

    Science.gov (United States)

    Machmudah, Siti; Wahyudiono; Takada, Noriharu; Kanda, Hideki; Sasaki, Koichi; Goto, Motonobu

    2013-12-01

    Pulsed laser ablation (PLA) has become a promising method for the synthesis of nanoclusters for photonics, electronics and medicine. In this work PLA in pressurized CO2 has been applied for fabrication of gold and silver nanoparticles. Laser ablation was performed with an excitation wavelength of 532 nm under various pressures (0.1-20 MPa), temperatures (40-80 °C) of CO2 medium and ablation times (1500-9000 s). On the basis of the experimental result, it follows that structures of gold (Au) and silver (Ag) nanoparticles were significantly affected by the changes in CO2 density. The structures of gold and silver nanoparticles also changed with an increase of ablation time. From a field-emission scanning electron microscopy (FE-SEM) image of the fabricated gold nano-structured particles on silicon wafer, it was seen that a network structure of smaller gold particles was fabricated. A similar morphology of particles fabricated from silver plate was observed. Silver particles contain nanoparticles with large-varied diameter ranging from 5 nm to 1.2 μm. The mechanism of nanoparticles fabrication could be observed as follows. Bigger gold/silver particles melted during the ablation process and then ejected smaller spherical nanoparticles, which formed nanoclusters attached on the molten particles.

  4. Attenuated effects of chitosan-capped gold nanoparticles on LPS-induced toxicity in laboratory rats

    Energy Technology Data Exchange (ETDEWEB)

    Stefan, Marius [Department of Biology, ' Alexandru Ioan Cuza' University, B-dul Carol I, No. 11, Iasi, 700506 (Romania); Melnig, Viorel; Pricop, Daniela [COMB Laboratory, ' Alexandru Ioan Cuza' University, B-dul Carol I, No. 11, Iasi, 700506 (Romania); Neagu, Anca; Mihasan, Marius [Department of Biology, ' Alexandru Ioan Cuza' University, B-dul Carol I, No. 11, Iasi, 700506 (Romania); Tartau, Liliana [' Gr.T. Popa' , University of Medicine and Pharmacy, 16 University Str., Iasi, 700115 (Romania); Hritcu, Lucian, E-mail: hritcu@uaic.ro [Department of Biology, ' Alexandru Ioan Cuza' University, B-dul Carol I, No. 11, Iasi, 700506 (Romania)

    2013-01-01

    The impact of nanoparticles in medicine and biology has increased rapidly in recent years. Gold nanoparticles (AuNP) have advantageous properties such as chemical stability, high electron density and affinity to biomolecules. However, the effects of AuNP on human body after repeated administration are still unclear. Therefore, the purpose of the present study was to evaluate the effects of gold-11.68 nm (AuNP1, 9.8 {mu}g) and gold-22.22 nm (AuNP2, 19.7 {mu}g) nanoparticles capped with chitosan on brain and liver tissue reactivity in male Wistar rats exposed to lipopolysaccharide (LPS from Escherichia coli serotype 0111:B4, 250 {mu}g) upon 8 daily sessions of intraperitoneal administration. Our results suggest that the smaller size of chitosan-capped AuNP shows the protective effects against LPS-induced toxicity, suggesting a very high potential for biomedical applications. - Highlights: Black-Right-Pointing-Pointer Smaller size of chitosan-capped gold nanoparticles acts against LPS-induced toxicity. Black-Right-Pointing-Pointer Larger size of chitosan-capped gold nanoparticles agglomerated inside neurons and induced toxicity in combination with LPS. Black-Right-Pointing-Pointer Chitosan has excellent biocompatible proprieties. Black-Right-Pointing-Pointer Smaller size of chitosan-capped gold nanoparticles demonstrates great potential in biomedical applications.

  5. High-resolution chemical imaging of gold nanoparticles using hard x-ray ptychography

    DEFF Research Database (Denmark)

    Hoppe, R.; Reinhardt, J.; Hofmann, G.

    2013-01-01

    We combine resonant scattering with (ptychographic) scanning coherent diffraction microscopy to determine the chemical state of gold nanoparticles with high spatial resolution. Ptychographic images of the sample are recorded for a series of energies around the gold L3 absorption edge. From these ...

  6. Polymer-templated self-assembly of a 2-dimensional gold nanoparticle network

    DEFF Research Database (Denmark)

    Hansen, Christian Rein; Westerlund, Fredrik; Moth-Poulsen, Kasper

    2008-01-01

    We here report on the formation of well-ordered 2D gold nanostructures at the air/water interface. Spreading a mixture of alkanethiol-capped gold nanoparticles (AuNPs) and an amphiphilic poly(p-phenylene) on a water surface and compressing the mixture to a surface pressure of 40 mN/m lead...

  7. Bringing Catalysis with Gold Nanoparticles in Green Solvents to Graduate Level Students

    Science.gov (United States)

    Raghuwanshi, Vikram Singh; Wendt, Robert; O'Neill, Maeve; Ochmann, Miguel; Som, Tirtha; Fenger, Robert; Mohrmann, Marie; Hoell, Armin; Rademann, Klaus

    2017-01-01

    We demonstrate here a novel laboratory experiment for the synthesis of gold nanoparticles (AuNPs) by using a low energy gold-sputtering method together with a modern, green, and biofriendly deep eutectic solvent (DES). The strategy is straightforward, economical, ecofriendly, rapid, and clean. It yields uniform AuNPs of 5 nm in diameter with high…

  8. Organosilane oxidation by water catalysed by large gold nanoparticles in a membrane reactor

    NARCIS (Netherlands)

    Gitis, V.; Beerthuis, R.; Shiju, N.R.; Rothenberg, G.

    2014-01-01

    We show that gold nanoparticles catalyse the oxidation of organosilanes using water as oxidant at ambient conditions. Remarkably, monodispersions of small gold particles (3.5 nm diameter) and large ones (6-18 nm diameter) give equally good conversion rates. This is important because separating large

  9. Adsorption and bioactivity of tyrosine hydroxylase on gold surfaces and nanoparticles.

    Science.gov (United States)

    Halskau, Oyvind; Volden, Sondre; Calvo, Ana C; Martínez, Aurora; Glomm, Wilhelm R

    2010-11-01

    Tyrosine hydroxylase is studied in terms of adsorption behaviour on gold surfaces and various passivating layers. Results reveal differences in layer formation, where mercaptoundecanoic acid-coated gold shows the best potential in terms of adsorbed mass. Nanoparticles with this coating are subsequently tested for enzymatic activity, which remains at attenuated levels.

  10. Preparation of gold nanoparticles by microwave heating and application of spectroscopy to study conjugate of gold nanoparticles with antibody E. coli O157:H7

    Science.gov (United States)

    Thanh Ngo, Vo Ke; Phuong Uyen Nguyen, Hoang; Phat Huynh, Trong; Nguyen Pham Tran, Nguyen; Lam, Quang Vinh; Dat Huynh, Thanh

    2015-09-01

    Gold nanoparticles (AuNPs) of 15-20 nm size range have attracted attention for producing smart sensing devices as diagnostic tools in biomedical sciences. Citrate capped AuNPs are negatively charged, which can be exploited for electrostatic interactions with some positively charged biomolecules like antibodies. In this paper we describe a method for the low cost synthesis of gold nanoparticles using sodium citrate (Na3Ct) reduction in chloroauric acid (HAuCl4.3H2O) by microwave heating (diameter about 13-15 nm). Gold nanoparticles were functionalized with surface activation by 3-mercaptopropionic acid for attaching antibody. These nanoparticles were then reacted with anti-E. coli O157:H7, using N-hydroxy succinimide (NHS) and carbondimide hydrochloride (EDC) coupling chemistry. The product was characterized with UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and zeta potential. In addition, the binding of antibody-gold nanoparticles conjugates to E. coli O157:H7 was demonstrated using transmission electron microscopy (TEM).

  11. Application of gold nanoparticles for improved drug efficiency

    Science.gov (United States)

    Shittu, K. O.; Bankole, M. T.; Abdulkareem, A. S.; Abubakre, O. K.; Ubaka, A. U.

    2017-09-01

    Due to increasing resistance of microorganisms towards current antibiotics, there is a need for new or enhanced antibiotics. Nanotechnology is a technology that enhances the use of gold nanoparticles (AuNP) in area of medical applications, especially as a drug carrier for targeted drug delivery. In this research, AuNPs was synthesized using biological method via bioreduction of Piper guineense aqueous leaf extract on tetra gold chloride, characterized using UV-Vis spectrophometer, DLS, TEM/EDS and FTIR. The synthesized AuNPs was covalently functionalized with polyethylene glycol and encapsulated with Lincomycin and in vitro dissolution methods was used to evaluate the potential performance of the formulated nanodrug. The nanodrug has highest release efficiency at the 9th minutes (23.4 mg ml-1 for 40 °C) and (29.5 mg ml-1 for 60 °C) compared with the non-nanodrug. The antibacterial potential of the nanodrug was seen on the gram-positive bacteria of Staphylococcus aureus and Streptococcus pyogenes with highest inhibitions of 18 mm (at 40 °C) and 16 mm (at 60 °C) for S. aureus, and 16 mm for S. pyogenes (both at 40 °C and 60 °C). The bacteria growth inhibition continued and lasted for 15 min, while that of non-nanodrug lasted for 9 min with lesser growth inhibition compared to the formulated nanodrug. This work shows that the presence of the AuNPs increased the release efficiency of lincomycin even at a lower concentration and also bacteria growth inhibition thereby suggesting the effectiveness of the nanodrug formulation.

  12. Polymer coated gold nanoparticles for tracing the mobility of engineered nanoparticles in the subsurface

    DEFF Research Database (Denmark)

    Uthuppu, Basil; Fjordbøge, Annika Sidelmann; Caspersen, Eva

    2014-01-01

    Nanoparticles (NPs) are manufactured for their specific properties providing possibilities for new and improved products and applications. The use of engineered nanoparticles (ENPs) has therefore brought significant innovation and advances to society, including benefits for human health...... as single particles. Coatings, including a large variety of natural and synthetic polymers, are used to enhance the colloid stability in high concentrations . However, increasing the stability of these materials may lead to unintended effects, such as enhancing their mobility in surface water...... of choice in this context. Also, the natural occurrence of these particles in the proposed environment is very rare. Laboratory based experiments conducted in sand columns show that stable aqueous suspensions of gold NPs coated with amphiphilic block co polymers (PVP-VA and PVA-COOH) are extremely mobile...

  13. Colorimetric detection of glucose based on gold nanoparticles coupled with silver nanoparticles

    Science.gov (United States)

    Gao, Yan; Wu, Yiting; Di, Junwei

    2017-02-01

    We have coupled gold nanoparticles (AuNPs) with silver nanoparticles (AgNPs) to assemble a plasmonic sensing platform for colorimetric detection of glucose. In this system, small AuNPs ( 4 nm) can act as glucose oxidase (GOD) mimic enzyme to catalytically oxidize glucose in the presence of oxygen, producing hydrogen peroxide, which dissolves AgNPs to lead the color changes. Glucose can be detected not only by naked eyes (from yellow to red) but also by spectrophotometer in the concentration range of 5-70 μM, with detection limit of 3 μM. More importantly, we found that L-cysteine added in the system can markedly improve the selectivity for the detection of glucose. The proposed method was used to application for the detection of glucose in human serum with satisfactory results. This system is simple and low cost without using any enzymes and organic chromogenic agents.

  14. Whole resting cells vs. cell free extracts of Candida parapsilosis ATCC 7330 for the synthesis of gold nanoparticles.

    Science.gov (United States)

    Krishnan, Saravanan; Narayan, Shoba; Chadha, Anju

    2016-12-01

    The cell free extracts of Candida parapsilosis ATCC 7330 are more efficient than the whole resting cells of the yeast in the synthesis of directly usable gold nanoparticles as revealed by this systematic study. Cell free extracts yielded gold nanoparticles of hydrodynamic diameter (50-200 nm). In this study, the total protein concentration influences the nanofabrication and not only the reductase enzymes as originally thought. Powder X-ray diffraction studies confirm the crystalline nature of the gold nanoparticles. Fourier Transform Infra Red spectroscopy and thermal gravimetric analysis suggests that the biosynthesized gold nanoparticles are capped by peptides/proteins. Dispersion experiments indicate a stable dispersion of gold nanoparticles in pH 12 solutions which is also confirmed by electron microscopic analysis and validated using a surface plasmon resonance assay. The effectiveness of the dispersed nanoparticles for the reduction of 4-nitrophenol using sodium borohydride as a reductant further confirms the formation of functional gold nanoparticles. It is also reported that gold nanoparticles with mean particle diameter of 27 nm are biosynthesized inside the whole cell by transmission electron microscopy analysis. With optimized reaction conditions, maximum gold bioaccumulation with the 24 h culture age of the yeast with cellular uptake of ~1010 gold atoms at the single cell level is achieved but it is not easy to extract the gold nanoparticles from the whole resting cells.

  15. Transplacental clastogenic and epigenetic effects of gold nanoparticles in mice

    Energy Technology Data Exchange (ETDEWEB)

    Balansky, Roumen [National Center of Oncology, Sofia (Bulgaria); Longobardi, Mariagrazia [Department of Health Sciences, University of Genoa, Genoa (Italy); Ganchev, Gancho; Iltcheva, Marietta [National Center of Oncology, Sofia (Bulgaria); Nedyalkov, Nikolay; Atanasov, Petar [Institute of Electronics, Bulgarian Academy of Sciences, Sofia (Bulgaria); Toshkova, Reneta [Institute of Experimental Morphology, Pathology and Anthropology with Museum, Bulgarian Academy of Sciences, Sofia (Bulgaria); De Flora, Silvio [Department of Health Sciences, University of Genoa, Genoa (Italy); Izzotti, Alberto, E-mail: izzotti@unige.it [Department of Health Sciences, University of Genoa, Genoa (Italy)

    2013-11-15

    Highlights: • We evaluated transplacental genotoxicity of 40 nm- and 100 nm-gold nanoparticles. • AuNP-100 nm significantly enhanced MN PCE in fetal liver and blood. • In fetal lung, out of 1281 miRNA analyzed, 28 were significantly altered in their expression. • In fetal liver, 5 miRNA were significantly altered in their expression. • Altered miRNAs are involved in cell proliferation, apoptosis, transcription, stress response. - Abstract: The broad application of nanotechnology in medicine, biology, and pharmacology is leading to a dramatic increase of the risk of direct contact of nanoproducts, among which gold nanoparticles (AuNP), with the human organism. The present study aimed at evaluating in vivo the genotoxicity of AuNPs with average size of 40 nm and 100 nm. A single intraperitoneal treatment of adult male and female Swiss mice (strain H) with AuNPs, at a dose of 3.3 mg/kg body weight, had no effect on the frequency of micronucleated polychromatic erythrocytes (MN PCEs) in bone marrow. Conversely, the transplacental treatment with AuNP-100 nm, but not with AuNP-40 nm, applied intraperitoneally at a dose of 3.3 mg/kg to pregnant mice on days 10, 12, 14, and 17 of gestation, resulted in a significant increase in the frequency of MN PCEs in both liver and peripheral blood of mouse fetuses. In parallel, the same treatment with AuNP-100 nm, but not with AuNP-40 nm, produced significant changes in microRNA expression. In particular, out of 1281 mouse microRNAs analyzed, 28 were dys-regulated more than two-fold and to a statistically significant extent in fetus lung, and 5 were up-regulated in fetal liver. Let-7a and miR-183 were significantly up-regulated in both organs. The data presented herein demonstrate for the first time the transplacental size-dependent clastogenic and epigenetic effects of AuNPs in mouse fetus, thus highlighting new aspects concerning the putative genotoxicity of AuNPs during a vulnerable period of life.

  16. Photocatalytic degradation of benzothiophene and dibenzothiophene using supported gold nanoparticle

    Directory of Open Access Journals (Sweden)

    Suzan Khayyat

    2017-03-01

    Full Text Available Photocatalytic oxidation of benzothiophene (BT and dibenzothiophene (DBT was studied over Au nanoparticles (NPs incorporated titania (Au/TiO2 catalyst under UV radiation using H2O2 as oxidant. The reaction parameters such as, catalyst weight, Au loading, calcination of Au/TiO2 catalysts and [H2O2]:[DBT] mole ratio are studied. The Au/TiO2 catalyst was synthesised by deposition–precipitation method. The catalysts were characterized by ICPAES, XRD and TEM analysis. ICP-AES analysis demonstrate that with a nominal amount of 1, 1.5, 2, 2.5 and 3 at.% of Au in a solution at pH 7, the amount of gold deposited on the TiO2 was 0.78, 1.42, 1.92, 2.45 and 2.87 at.% respectively. The average particle size of Au in the 2 at.% Au/TiO2 sample after drying was 3 nm and in the sample after calcination at 573 K was 5 nm. The XPS spectra of Au/TiO2 sample demonstrate that the sample dried at 373 K contains Au0 and Au3+ and the sample after calcination at 573 K contains Au0 and negligible amount of Au3+. The photocatalysis studies show that the Au nanoparticles (NPs incorporated titania showed higher activity for the removal of DBT compared to pure titania. The optimum Au loading in Au/TiO2 for the photocatalytic removal of DBT was found to be 1.5 at.% Au. The Au NPs act as electron sink to enhance e/h+ charge separation and produce number of oxidizing species, thereby increase the reaction rate. The calcined catalyst sample showed higher activity toward DBT removal compared to the uncalcined sample. This is due to the presence of metallic gold in the calcined sample, which can effectively involve in the charge separation. The optimum catalyst weight for DBT removal was found to be 0.3 g of Au/TiO2 for 200 ml of DBT in isooctane (200 ppm S. The optimum [H2O2]:[DBT] molar ratio was found to be 3. Comparison of photocatalytic removal of DBT and BT showed that the removal of DBT is faster than the BT.

  17. Graphene oxide-promoted reshaping and coarsening of gold nanorods and nanoparticles.

    Science.gov (United States)

    Pan, Hanqing; Low, Serena; Weerasuriya, Nisala; Shon, Young-Seok

    2015-02-11

    This paper describes thermally induced reshaping and coarsening behaviors of gold nanorods and nanoparticles immobilized on the surface of graphene oxide. Cetyltrimethylammonium bromide-stabilized gold nanorods with an aspect ratio of ∼3.5 (54:15 nm) and glutathione-capped gold nanoparticles with an average core size of ∼3 nm were synthesized and self-assembled onto the surface of graphene oxide. The hybrid materials were then heated at different temperatures ranging from 50 to 300 °C. The effects of heat treatments were monitored using UV-vis spectroscopy and transmission electron microscopy (TEM). These results were directly compared with those of heat-treated free-standing gold nanorods and nanoparticles without graphene oxide to understand the heat-induced morphological changes of the nanohybrids. The obtained results showed that the gold nanorods would undergo a complete reshaping to spherical particles at the temperature of 50 °C when they are assembled on graphene oxide. In comparison, the complete reshaping of free-standing gold nanorods to spherical particles would ultimately require a heating of the samples at 200 °C. In addition, the spherical gold nanoparticles immobilized on graphene oxide would undergo a rapid coarsening at the temperature of 100-150