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

Science.gov (United States)

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

2014-09-01

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

Optical properties of monodispersive FePt nanoparticle films

Energy Technology Data Exchange (ETDEWEB)

Lee, S.J.; Lo, C.C.H. [Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Yu, A.C.C. [Sony Corporation, Sendai Technology Center, 3-4-1 Sakuragi, Miyagi 985-0842 (Japan); Fan, M. [Center for Sustainable Environmental Technologies, Iowa State University, Ames, IA 50011 (United States)

2004-10-01

The optical properties of monodispersive FePt nanoparticle films were investigated using spectroscopic ellipsometry in the energy range of 1.5 to 5.5 eV. The monodispersive FePt nanoparticle film was stabilized on a Si substrate by means of an organosilane coupling film, resulting in the formation of a (Si/SiO{sub 2}/APTS/FePt nanoparticles monolayer) structure. Multilayer optical models were employed to study the contribution of the FePt nanoparticles to the measured optical properties of the monodispersive FePt nanoparticle film, and to estimate the optical properties of the FePt nanoparticle layer. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Green Synthesis of Robust, Biocompatible Silver Nanoparticles Using Garlic Extract

International Nuclear Information System (INIS)

White, G.V.; Kerscher, P.; Brown, R.M.; Morella, J.D.; Kitchens, C.L.; McAllister, W.; Dean, D.

2012-01-01

This paper details a facile approach for the synthesis of stable and monodisperse silver nanoparticles performed at ambient/low temperature, where Allium sativum (garlic) extract functions as the silver salt reducing agent during nanoparticle synthesis as well as the post synthesis stabilizing ligands. Varying the synthesis conditions provides control of particle size, size-distribution, and kinetics of particle formation. Infrared spectroscopy, energy dispersive X-ray chemical analysis, and high-performance liquid chromatography indicated that allicin and other carbohydrates in the garlic extract are the primary nanoparticle stabilizing moieties. The synthesized silver nanoparticles also demonstrate potential for biomedical applications, owing to (1) enhanced stability in biological media, (2) resistance to oxidation by the addition of H 2 O 2 , (3) ease and scalability of synthesis, and (4) lack of harsh chemicals required for synthesis. Cytotoxicity assays indicated no decrease in cellular proliferation for vascular smooth muscle cells and 3T3 fibroblasts at a concentration of 25 μg/mL, confirming that silver nanoparticles synthesized with garlic extract are potential candidates for future experimentation and implementation in the biomedical field.

Synthesis of self-assembly plasmonic silver nanoparticles with tunable luminescence color

International Nuclear Information System (INIS)

Al-Ghamdi, Haifa S.; Mahmoud, Waleed E.

2014-01-01

Assembly is an elegant and effective bottom-up approach to prepare arrays of nanoparticles from nobel metals. Noble metal nanoparticles are perfect building blocks because they can be prepared with an adequate functionalization to allow their assembly and with controlled sizes. Herein, we report a novel recipe for the synthesis of self-assembled silver nanoparticles with tunable optical properties and sizes. The synthetic route followed here based on the covalent binding among silver nanoparticles by means of poly vinyl alcohol for the first time. The size of silver nanoparticle is governed by varying the amount of sodium borohydride. The as-synthesized nanoparticles were characterized by transmission electron microscopy, x-ray diffraction, energy dispersive x-ray spectroscopy, selected area electron diffraction and UV–vis spectroscopy. Results depicted that self-assembly of mono-dispersed silver nanoparticles with different sizes have been achieved. The silver nanostructure has a single crystalline faced centered cubic structure with growth orientation along (1 1 1) facet. These nanoparticles exhibited localized surface plasmon resonance at 403 nm. The luminescence peaks were red-sifted from violet to green due to the increase of the particle sizes. -- Highlights: • Self-assembled silver nanoparticles based PVA were synthesized. • NaBH 4 amount was found particle size dependent. • Silver nanoparticles strongly affected the surface plasmon resonance. • Highly symmetric luminescence emission band narrow width is obtained. • Dark field image showed a tunable color change from violet to green

Size-tunable silver nanoparticles synthesized by using aminopolycarboxylic acids at ambient-temperature

International Nuclear Information System (INIS)

Malkar, Vishwabharati V.; Chadha, R.; Biswas, N.; Mukherjee, T.; Kapoor, S.

2009-01-01

Full text: Stable aqueous sols of silver nanoparticles are prepared by using various aminopolycarboxylic acids as stabilizing agents at ambient temperature. The precursor silver perchlorate is reduced using γ radiations. Interestingly, it was observed that size of silver nanoparticles obtained could be tuned using various aminopolycarboxylic acids of varying carboxylic acid groups The silver sols synthesized by this method were stable for months and particles obtained were monodisperse in almost all cases. Particle formation was observed at equimolar concentration of silver and aminopolycarboxylic acids. The stabilization of particles even in the absence of any polymer indicates that the adsorption of aminopolycarboxylic acids on silver particle is a spontaneous process. The adsorbed aminopolycarboxylic acids can saturate the residual valence force of the silver atom on the particle surface by coordinating with unoccupied orbital. Adsorption of aminopolycarboxylic acids does not lead to any change in surface plasmon band of silver nanoparticles; this indicates that anions in the double layer on the colloidal particle have different chemical properties from the free anions. Synthesized silver nanoparticles were characterized by UV-visible spectrophotometer, X-ray Diffraction, Dynamic Light Scattering and Transmission Electron Microscope

Nucleation and Growth of Ordered Arrays of Silver Nanoparticles on Peptide Nanofibers: Hybrid Nanostructures with Antimicrobial Properties.

Science.gov (United States)

Pazos, Elena; Sleep, Eduard; Rubert Pérez, Charles M; Lee, Sungsoo S; Tantakitti, Faifan; Stupp, Samuel I

2016-05-04

Silver nanoparticles have been of great interest as plasmonic substrates for sensing and imaging, catalysts, or antimicrobial systems. Their physical properties are strongly dependent on parameters that remain challenging to control such as size, chemical composition, and spatial distribution. We report here on supramolecular assemblies of a novel peptide amphiphile containing aldehyde functionality in order to reduce silver ions and subsequently nucleate silver metal nanoparticles in water. This system spontaneously generates monodisperse silver particles at fairly regular distances along the length of the filamentous organic assemblies. The metal-organic hybrid structures exhibited antimicrobial activity and significantly less toxicity toward eukaryotic cells. Metallized organic nanofibers of the type described here offer the possibility to create hydrogels, which integrate the useful functions of silver nanoparticles with controllable metallic content.

Synthesis of Monodisperse Iron Oxide Nanoparticles without Surfactants

Directory of Open Access Journals (Sweden)

Xiao-Chen Yang

2014-01-01

Full Text Available Monodisperse iron oxide nanoparticles could be successfully synthesized with two kinds of precipitants through a precipitation method. As-prepared nanoparticles in the size around 10 nm with regular spherical-like shape were achieved by adjusting pH values. NaOH and NH3·H2O were used as two precipitants for comparison. The average size of nanoparticles with NH3·H2O precipitant got smaller and represented better dispersibility, while nanoparticles with NaOH precipitant represented better magnetic property. This work provided a simple method without using any organic solvents, organic metal salts, or surfactants which could easily obtain monodisperse nanoparticles with tunable morphology.

The preparation of highly active antimicrobial silver nanoparticles by an organometallic approach

International Nuclear Information System (INIS)

Fernandez, Eduardo J; Garcia-Barrasa, Jorge; Lopez-de-Luzuriaga, Jose M; Monge, Miguel; Laguna, Antonio; Torres, Carmen

2008-01-01

Silver nanoparticles of small size with a high surface to volume ratio have been prepared using an organometallic approach. For this, the complex NBu 4 [Ag(C 6 F 5 ) 2 ] has been treated with AgClO 4 in a 1:1 molar ratio, giving rise to the nanoparticle precursor [Ag(C 6 F 5 )] in solution. Addition of one equivalent of hexadecylamine (HDA) and 5 h of reflux in toluene leads to a deep yellow solution containing monodisperse silver nanoparticles (Ag NPs) of ca. 10 nm. This approach leads to nanoparticles with almost uncontaminated surfaces which make them very reactive. Antimicrobial studies show that these nanoparticles are very active as antimicrobial agents. Very low concentrations between 12 and 25 μg ml -1 of Ag NPs are enough to produce bacteriostatic and bactericidal effectiveness

The preparation of highly active antimicrobial silver nanoparticles by an organometallic approach

Energy Technology Data Exchange (ETDEWEB)

Fernandez, Eduardo J; Garcia-Barrasa, Jorge; Lopez-de-Luzuriaga, Jose M; Monge, Miguel [Departamento de Quimica Grupo de SIntesis Quimica de La Rioja, UA-CSIC, Universidad de La Rioja, Complejo CientIfico-Tecnologico, E-26004 Logrono (Spain); Laguna, Antonio [Departamento de Quimica Inorganica, Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza-CSIC, E-50009 Zaragoza (Spain); Torres, Carmen [Departamento de Agricultura y Alimentacion, Universidad de La Rioja, Complejo Cientifico-Tecnologico, E-26004 Logrono (Spain)], E-mail: eduardo.fernandez@unirioja.es

2008-05-07

Silver nanoparticles of small size with a high surface to volume ratio have been prepared using an organometallic approach. For this, the complex NBu{sub 4}[Ag(C{sub 6}F{sub 5}){sub 2}] has been treated with AgClO{sub 4} in a 1:1 molar ratio, giving rise to the nanoparticle precursor [Ag(C{sub 6}F{sub 5})] in solution. Addition of one equivalent of hexadecylamine (HDA) and 5 h of reflux in toluene leads to a deep yellow solution containing monodisperse silver nanoparticles (Ag NPs) of ca. 10 nm. This approach leads to nanoparticles with almost uncontaminated surfaces which make them very reactive. Antimicrobial studies show that these nanoparticles are very active as antimicrobial agents. Very low concentrations between 12 and 25 {mu}g ml{sup -1} of Ag NPs are enough to produce bacteriostatic and bactericidal effectiveness.

Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

International Nuclear Information System (INIS)

Wen Li; Lin Zhonghua; Gu Pingying; Zhou Jianzhang; Yao Bingxing; Chen Guoliang; Fu Jinkun

2009-01-01

Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 o C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (<2.5 nm), hold the shape of spherical nanoparticles, and promote the monodispersity of nanoparticles. Through the modulation of reaction time and the use of thiol, monodispersed spherical gold nanoparticles capped with thiol of 1.9 ± 0.8 nm size were formed by using Bacillus megatherium D01.

Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

Energy Technology Data Exchange (ETDEWEB)

Wen Li [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Lin Zhonghua [Xiamen University, State Key Laboratory of Physical Chemistry of Solid Surfaces (China); Gu Pingying [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Zhou Jianzhang [Xiamen University, State Key Laboratory of Physical Chemistry of Solid Surfaces (China); Yao Bingxing [Xiamen University, School of Life Sciences (China); Chen Guoliang; Fu Jinkun, E-mail: wenli_1976@163.co [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China)

2009-02-15

Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 {sup o}C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (<2.5 nm), hold the shape of spherical nanoparticles, and promote the monodispersity of nanoparticles. Through the modulation of reaction time and the use of thiol, monodispersed spherical gold nanoparticles capped with thiol of 1.9 {+-} 0.8 nm size were formed by using Bacillus megatherium D01.

Preparation of mono-dispersed silver nanoparticles assisted by chitosan-g-poly(ε-caprolactone) micelles and their antimicrobial application

Energy Technology Data Exchange (ETDEWEB)

Gu, Chunhua [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Huan [State Key Laboratory of Bioreactor Engineering, New World Biotechnology Institute, East China University of Science and Technology, Shanghai 200237 (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2014-05-01

Graphical abstract: - Highlights: • Chemical modification of chitosan were conducted after phthaloyl protection of amino groups. • Silver nanoparticles were prepared in the presence of chitosan-based copolymer micelles. • The optimal time scale and weight ratios of silver to micelles were monitored by UV–vis spectrometer. - Abstract: Amphiphilic chitosan-graft-poly(ε-caprolactone) (CS-g-PCLs) copolymers were synthesized by a homogeneous coupling method and characterized by {sup 1}H NMR, FTIR and ninhydrin assay. The graft copolymers were subsequently self-assembled into micelles, which were measured by DLS and TEM. The particle size of the micelles decreased as the segment grafting fraction was increased. Thereafter, silver nanoparticles were prepared in the presence of chitosan-based micelles under UV irradiation. The molar ratio and radiation time of silver to micelles were optimized with process monitored via UV–vis spectrophotometer. DLS and TEM were used to illustrate the particle structure and size while XRD patterns were applied to characterize the crystal structures of polymer-assisted silver nanoparticles. Films impregnated with silver nanoparticles were conducted with results of strong antimicrobial activities against Escherichia coli and Staphylococcus aureus as model Gram-negative and positive bacteria.

Preparation of mono-dispersed silver nanoparticles assisted by chitosan-g-poly(ε-caprolactone) micelles and their antimicrobial application

International Nuclear Information System (INIS)

Gu, Chunhua; Zhang, Huan; Lang, Meidong

2014-01-01

Graphical abstract: - Highlights: • Chemical modification of chitosan were conducted after phthaloyl protection of amino groups. • Silver nanoparticles were prepared in the presence of chitosan-based copolymer micelles. • The optimal time scale and weight ratios of silver to micelles were monitored by UV–vis spectrometer. - Abstract: Amphiphilic chitosan-graft-poly(ε-caprolactone) (CS-g-PCLs) copolymers were synthesized by a homogeneous coupling method and characterized by 1 H NMR, FTIR and ninhydrin assay. The graft copolymers were subsequently self-assembled into micelles, which were measured by DLS and TEM. The particle size of the micelles decreased as the segment grafting fraction was increased. Thereafter, silver nanoparticles were prepared in the presence of chitosan-based micelles under UV irradiation. The molar ratio and radiation time of silver to micelles were optimized with process monitored via UV–vis spectrophotometer. DLS and TEM were used to illustrate the particle structure and size while XRD patterns were applied to characterize the crystal structures of polymer-assisted silver nanoparticles. Films impregnated with silver nanoparticles were conducted with results of strong antimicrobial activities against Escherichia coli and Staphylococcus aureus as model Gram-negative and positive bacteria

Moderating effect of ammonia on particle growth and stability of quasi-monodisperse silver nanoparticles synthesized by the Turkevich method.

Science.gov (United States)

Gorup, Luiz F; Longo, Elson; Leite, Edson R; Camargo, Emerson R

2011-08-15

A new method to stabilize silver nanoparticles by the addition of ammonia is proposed. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C. After approximately 12 min, a diluted ammonia solution was added to the reaction flask to form soluble diamine silver (I) complexes that played an important growth moderating role, making it possible to stabilize metallic silver nanoparticles with sizes as small as 1.6 nm after 17 min of reaction. Colloidal dispersions were characterized by UV-visible absorption spectroscopy, X-ray diffraction, and transmission electronic microscopy. Copyright © 2011 Elsevier Inc. All rights reserved.

Green synthesis and characterization of monodispersed silver nanoparticles using root bark aqueous extract of Annona muricata Linn and their antimicrobial activity

Science.gov (United States)

Ezealisiji, K. M.; Noundou, X. S.; Ukwueze, S. E.

2017-11-01

In recent time, various phytosynthetic methods have been employed for the fabrication of silver nanoparticles; these unique metal nanoparticles are used in several applications which include pharmaceuticals and material engineering. The current research reports a rapid and simple synthetic partway for silver nanoparticles (AgNPs) using root bark aqueous extract of Annona muricata and the evaluation of its antimicrobial efficacy against pathogenic microorganisms. The root bark extract was treated with aqueous silver nitrate solution. Silver ions were reduced to silver atoms which on aggregation gave Silver nanoparticles; the biosynthesized AgNPs were characteristically spherical, discreet and stabilized by phytochemical entities and were characterized using ultraviolet visible spectroscopy, transmission electron microscope (TEM) and photon correlation microscopy. The aqueous plant extract-AgNPs suspension was subjected to Fourier transform infrared spectroscopy. TEM result for the average particle size is 22 ± 2 nm. The polydispersity index and zeta-potential were found to be 0.44 ± 0.02 and - 27.90 ± 0.01 mV, respectively (Zeta-Sizer). The antimicrobial evaluation result showed that the synthesized silver nanoparticles at different concentration were very active against the Gram-positive bacteria ( B. subtilis, S. aureous) and Gram-negative bacteria ( K. Pneumonia, E. Coli and Pseudomonas aeruginosa), P. aeruginosa being most susceptible to the anti microbial effect of the silver nanoparticles. Stable silver nanoparticles with antimicrobial activity were obtained through biosynthesis.

Green biosynthesis of silver nanoparticles using pomegranate peel and inhibitory effects of the nanoparticles on aflatoxin production

International Nuclear Information System (INIS)

Monira, A.O.; Mohammad, M.A.; Ashraf, H.A.

2017-01-01

In this work, pomegranate peel has been used as a natural and safe method for biosynthesis of silver nanoparticles. The synthesis of silver nanoparticles was confirmed using UV spectroscopy, which showed a peak around a wavelength of 437 nm. The morphology showed spherical and monodispersed nanoparticles with a size range between 5-50 nm. Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD) experiments revealed their crystalline nature. Active functional groups in the synthesized silver nanoparticles were determined using Fourier transform infrared (FTIR) spectrometers contained four bands at 3281.21 cm/sup -1/, possibly indicating the participationof O-H functional group. The peak take place at 1,636.22 cm/sup -1/ may be pointed to C = N bending in the amide group or C = O stretching in carboxyl. Transfer in this peak (from 1,641 to 1,643 cm/sup -1/) shown the possible role of amino groups or carboxyl in nanoparticle synthesis. The peaks at 431.95 and 421.28 cm/sup -1/ be related to AgNPs bonding with oxygen from hydroxyl groups which confirm the role of pomegranate peel as a reducing agent. Furthermore, we investigated effects of these nanoparticles on aflatoxin B1 production by the fungus Aspergillus flavus, isolated from hazelnut. The results found that aflatoxin production in all A. flavus isolates decreased with an increase in the concentration of silver nanoparticles. Maximum suppression of aflatoxin production was recorded at a nanoparticle concentration of 150 ppm. (author)

Production of Monodisperse Nanoparticles and Application of Discrete-Monodisperse Model in Plasma Reactors

International Nuclear Information System (INIS)

Kim, Dong-Joo; Kim, Kyo-Seon; Zhao, Qian-Qiu

2003-01-01

The particle growth in plasma reactor were investigated by using the discrete-monodisperse (D-M) model for various process conditions. The monodisperse large sized particle distribution predicted by the D-M model are in good agreement with the large sized particles by the discrete-sectional model and also in the experiments by Shiratani et al. (1996). Some fractions of the small size particles are in a neutral state or even charged positively, but most of the large sized monodisperse particles are charged negatively. As the mass generation rate of monomers increases, the large sized particles grow more quickly and the production rate of nanoparticles of 100nm by plasma reactor increases. As the initial electron concentration or the monomer diameter increases, it takes longer time for the large sized particles to grow up to 100nm, but the large sized particle concentration of 100nm increases and the resulting production rate of large sized particles of 100nm increases. As the residence time increases, the time for the large sized particles to grow up to 100nm decreases and the large sized particle concentration of 100nm increases and, as a result, the production rate of large sized particles of 100nm increases. We propose that the plasma reactor can be a good candidate to produce monodisperse nanoparticles

Synthesis of Monodispersed Spherical Single Crystalline Silver Particles by Wet Chemical Process; Shisshiki kagakuho ni yoru tanbunsankyujo tankesshoginryushi no gose

Energy Technology Data Exchange (ETDEWEB)

Ueyama, Ryousuke.; Harada, Masahiro.; Ueyama, Tamotsu.; Harada, Akio. [Daiken Chemistry Industry Corporation, Osaka (Japan); Yamamoto, Takashi. [National Defence Academy, Kanagawa (Japan). Dept. of Electrical Engineering; Shiosaki, Tadashi. [Nara Institute of Science and Technology, Nara (Japan). Graduate School of Materials Science; Kuribayashi, Kiyoshi. [Teikyo University of Science and Technology, Yamanashi (Japan). Dept. of Materials

1999-01-01

Ultrafine silver monodispersed particle were prepared by wet chemical process. To decrease the reduction speed, an important factor in generating monodispersed particles is to control the following three factors: synthesis temperature, concentration of aggregation-relaxing agent added, and concentration of silver nitrate solution. Synthesis of monodispersed spherical Ag particles, used as metal powders for electrode, became possible using the nucleus grouwth reaction method. This process also allowed the control of the diameter of the powder particles. The silver particles were distributed in ta narrow particle diameter range with on average of 0.5 {mu}m. Transmission electron microscopy (TEM) revealed that single-crystalline silver particles were prepared by the present method. (author)

Rod-shaped silica particles derivatized with elongated silver nanoparticles immobilized within mesopores

Energy Technology Data Exchange (ETDEWEB)

Mnasri, Najib [Institut Charles Gerhardt de Montpellier, CNRS UMR 5253, Université Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France); Materials, Environment and Energy Laboratory (UR14ES26), Faculty of Science, University of Gafsa, 2112 Gafsa (Tunisia); Charnay, Clarence; Ménorval, Louis-Charles de [Institut Charles Gerhardt de Montpellier, CNRS UMR 5253, Université Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France); Elaloui, Elimame [Materials, Environment and Energy Laboratory (UR14ES26), Faculty of Science, University of Gafsa, 2112 Gafsa (Tunisia); Zajac, Jerzy, E-mail: jerzy.zajac@umontpellier.fr [Institut Charles Gerhardt de Montpellier, CNRS UMR 5253, Université Montpellier, Place Eugène Bataillon, 34095 Montpellier Cedex 5 (France)

2016-11-15

Silver-derivatized silica particles possessing a non-spherical morphology and surface plasmon resonance properties have been achieved. Nanometer-sized silica rods with uniformly sized mesopore channels were prepared first making use of alkyltrimethyl ammonium surfactants as porogens and the 1:0.10 tetraethyl orthosilicate (TEOS) : 3-aminopropyltriethoxysilane (APTES) mixture as a silicon source. Silica rods were subsequently functionalized by introducing elongated silver nanoparticles within the intra-particle mesopores thanks to the AgNO{sub 3} reduction procedure based on the action of hemiaminal groups previously located on the mesopore walls. The textural and structural features of the samples were inferred from the combined characterization studies including SEM and TEM microscopy, nitrogen adsorption-desorption at 77 K, powder XRD in the small- and wide-angle region, as well as UV–visible spectroscopy. {sup 129}Xe NMR spectroscopy appeared particularly useful to obtain a correct information about the porous structure of rod-shaped silica particles and the silver incorporation within their intra-particle mesopores. - Highlights: • Mesoporous monodisperse submicron-sized silica rods were achieved. • Silver nanoparticles were located lengthwise within the intra-particle mesopores. • Textural and plasmonic properties of particles studied by {sup 129}Xe NMR and UV–Vis.

Green synthesis of silver nanoparticles using Beta vulgaris: Role of process conditions on size distribution and surface structure

Energy Technology Data Exchange (ETDEWEB)

Parameshwaran, R., E-mail: parameshviews@gmail.com [Department of Mechanical Engineering, Anna University, Chennai 600 025 (India); Centre for Nanoscience and Technology, Anna University, Chennai 600 025 (India); Kalaiselvam, S., E-mail: kalai@annauniv.edu [Centre for Nanoscience and Technology, Anna University, Chennai 600 025 (India); Department of Applied Science and Technology, Anna University, Chennai 600 025 (India); Jayavel, R., E-mail: rjvel@annauniv.edu [Centre for Nanoscience and Technology, Anna University, Chennai 600 025 (India)

2013-06-15

The present work reports the green synthesis of silver nanoparticles, using Beta vulgaris peel extract with a subsequent investigation on the size distribution and surface structure of nanoparticles formed under various process conditions. The green-chemical reduction mechanism of silver ions to nanoparticles by the active organic functional groups present in the extract was characterized, using the respective spectroscopic techniques. The effects of various process parameters, including induced intraparticle ripening, were attributed to the controlled formation of anisotropic silver nanoparticles within the supporting matrix of the extract. The plasmon absorption and resonance scattering properties were expected to be favourable for small and larger size nanoparticles (below 25 nm and above 75 nm) respectively, which was considered to be an indicative aspect for synthesizing nanoparticles of narrow size distribution. The zeta potential and dynamic light scattering (DLS) results suggest the good stability and mono-dispersed size distribution of the silver nanoparticles. The transmission electron microscope, selective area electron diffraction (SAED) and X-ray diffraction studies infer that the nanoparticles formed were spherical/quasi-spherical in shape, which primarily exhibited a face centred cubic crystal (FCC) structure. The green-chemical reduction of organic phases in the extract (especially amine (NH{sub 2}) groups) as reflected through shifts observed in the Fourier-transform infra red (FTIR) peaks, reveal the possible interaction of the organic molecules with the silver ions in the effective formation, surface modification and stabilization of the silver nanoparticles. - Highlights: • Functionally stable and crystalline silver nanoparticles were green synthesized. • Beta vulgaris peel extract was used as potential reducing and stabilizing agent. • Amine groups in extract were expected to reduce Ag{sup +} and stabilize nanoparticles. • Induced

Green synthesis of silver nanoparticles using Beta vulgaris: Role of process conditions on size distribution and surface structure

International Nuclear Information System (INIS)

Parameshwaran, R.; Kalaiselvam, S.; Jayavel, R.

2013-01-01

The present work reports the green synthesis of silver nanoparticles, using Beta vulgaris peel extract with a subsequent investigation on the size distribution and surface structure of nanoparticles formed under various process conditions. The green-chemical reduction mechanism of silver ions to nanoparticles by the active organic functional groups present in the extract was characterized, using the respective spectroscopic techniques. The effects of various process parameters, including induced intraparticle ripening, were attributed to the controlled formation of anisotropic silver nanoparticles within the supporting matrix of the extract. The plasmon absorption and resonance scattering properties were expected to be favourable for small and larger size nanoparticles (below 25 nm and above 75 nm) respectively, which was considered to be an indicative aspect for synthesizing nanoparticles of narrow size distribution. The zeta potential and dynamic light scattering (DLS) results suggest the good stability and mono-dispersed size distribution of the silver nanoparticles. The transmission electron microscope, selective area electron diffraction (SAED) and X-ray diffraction studies infer that the nanoparticles formed were spherical/quasi-spherical in shape, which primarily exhibited a face centred cubic crystal (FCC) structure. The green-chemical reduction of organic phases in the extract (especially amine (NH 2 ) groups) as reflected through shifts observed in the Fourier-transform infra red (FTIR) peaks, reveal the possible interaction of the organic molecules with the silver ions in the effective formation, surface modification and stabilization of the silver nanoparticles. - Highlights: • Functionally stable and crystalline silver nanoparticles were green synthesized. • Beta vulgaris peel extract was used as potential reducing and stabilizing agent. • Amine groups in extract were expected to reduce Ag + and stabilize nanoparticles. • Induced intraparticle

Sonochemical synthesis of (3-aminopropyl)triethoxysilane-modified monodispersed silica nanoparticles for protein immobilization

International Nuclear Information System (INIS)

Shen, Shou-Cang; Ng, Wai Kiong; Chia, Leonard; Dong, Yuan-Cai; Tan, Reginald B.H.

2011-01-01

Graphical abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by rapid sonochemical co-condensation to achieve high capability for protein immobilization. Highlights: → Amino-modified monodispersed silica nanoparticles were synthesized by rapid co-condensation. → Strong positive charge was created by aminopropyl-modification. → Capability for immobilization of negatively charged protein was enhanced. → Electrostatic interaction between proteins and surface contributed to the enhanced adsorption. -- Abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by a rapid sonochemical co-condensation synthesis procedure. The chemical nature of surface organic modifier on the obtained modified silica nanoparticle was characterized by 13 C and 29 Si MAS Nuclear Magnetic Resonance (NMR) spectroscopies, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)- differential scanning calorimetry (DSC). Due to the strengthened positive surface charge of the silica nanoparticles by the modification with aminopropyl groups, the capability for bovine serum albumin (BSA) adsorption was significantly increased as compared with bare silica nanoparticles. 80 mg/g BSA was adsorbed on modified silica nanoparticles, whereas only 20 mg/g BSA could be loaded on pure silica nanoparticles. The enhanced positive surface charge repelled proteins with net positive charge and the modified silica nanoparticles exhibited negligible adsorption of lysozyme, thus a selective adsorption of proteins could be achieved.

Sonochemical synthesis of (3-aminopropyl)triethoxysilane-modified monodispersed silica nanoparticles for protein immobilization

Energy Technology Data Exchange (ETDEWEB)

Shen, Shou-Cang, E-mail: shen_shoucang@ices.a-star.edu.sg [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Ng, Wai Kiong; Chia, Leonard; Dong, Yuan-Cai [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Tan, Reginald B.H., E-mail: reginald_tan@ices.a-star.edu.sg [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Department of Chemical and Biomolecular Engineering, The National University of Singapore, 4 Engineering Drive 4, Singapore 117576 (Singapore)

2011-10-15

Graphical abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by rapid sonochemical co-condensation to achieve high capability for protein immobilization. Highlights: {yields} Amino-modified monodispersed silica nanoparticles were synthesized by rapid co-condensation. {yields} Strong positive charge was created by aminopropyl-modification. {yields} Capability for immobilization of negatively charged protein was enhanced. {yields} Electrostatic interaction between proteins and surface contributed to the enhanced adsorption. -- Abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by a rapid sonochemical co-condensation synthesis procedure. The chemical nature of surface organic modifier on the obtained modified silica nanoparticle was characterized by {sup 13}C and {sup 29}Si MAS Nuclear Magnetic Resonance (NMR) spectroscopies, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)- differential scanning calorimetry (DSC). Due to the strengthened positive surface charge of the silica nanoparticles by the modification with aminopropyl groups, the capability for bovine serum albumin (BSA) adsorption was significantly increased as compared with bare silica nanoparticles. 80 mg/g BSA was adsorbed on modified silica nanoparticles, whereas only 20 mg/g BSA could be loaded on pure silica nanoparticles. The enhanced positive surface charge repelled proteins with net positive charge and the modified silica nanoparticles exhibited negligible adsorption of lysozyme, thus a selective adsorption of proteins could be achieved.

Metal Fe3+ ions assisted synthesis of highly monodisperse Ag/SiO2 nanohybrids and their antibacterial activity

International Nuclear Information System (INIS)

Zhang, Nianchun; Xue, Feng; Yu, Xiang; Zhou, Huihua; Ding, Enyong

2013-01-01

Graphical abstract: TEM images of the Ag/SiO 2 -2 nanohybrids. The homogeneous and more mono-disperse Ag nanoparticles deposit on SiO 2 spheres. Through this method, Ag nanoparticles are easily formed on the surface of SiO 2 compared to other methods. Highlights: ► We prepared homogeneous and mono-dispersed Ag/SiO 2 -2 nanohybrids by adding Fe 3+ ions. ► The Ag/SiO 2 -2 nanohybrids had core(SiO 2 )-shell(Ag) structure. ► The Ag/SiO 2 -2 nanohybrids exhibited excellent antibacterial activity against bacteria. ► The reaction temperature was lower and the yield of Ag/SiO 2 -2 nanohybrids were higher. - Abstract: Highly monodispersed Ag/SiO 2 nanohybrids with excellent antibacterial property were synthesized by using DMF as a reducing agent and employing an additional redox potential of metal Fe 3+ ion as a catalytic agent. The obtained Ag/SiO 2 -2 nanohybrids of about 240 nm were highly monodispersity and uniformity by adding trace Fe 3+ ions into the reaction which Ag + reacted with N,N-dimethyl formamide (DMF) at 70 °C. Compared to the conventional techniques, which need long time and high temperature for silica coating of Ag nanoparticles, this new method was capable of synthesizing monodispersed, uniform, high yield Ag/SiO 2 nanohybrids. The electron was transferred from the Fe 2+ ion to the Ag + ion to accelerate the nucleation of silver nanoparticles. The chemical structures, morphologies and properties of the Ag/SiO 2 nanohybrids were characterized by X-ray diffraction (XRD), (High-resolution, Scanning transmission) transmission electron microscopy (TEM, HRTEM and STEM), and X-ray photoelectron spectroscopy (XPS), and UV–vis spectroscopy (UV–vis) and test of antibacterial. The results demonstrated that the silver nanoparticles supported on the surface of SiO 2 spheres in Ag/SiO 2 -2 nanohybrids structure, the Ag nanoparticles were homogeneous and monodispersed. The results also indicated that the Ag/SiO 2 -2 nanohybrid had excellent antibacterial.

Antimicrobial active silver nanoparticles and silver/polystyrene core-shell nanoparticles prepared in room-temperature ionic liquid

International Nuclear Information System (INIS)

An Jing; Wang Desong; Luo Qingzhi; Yuan Xiaoyan

2009-01-01

Uniform silver nanoparticles and silver/polystyrene core-shell nanoparticles were successfully synthesized in a room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM].BF 4 ). [BMIM].BF 4 plays a protective role to prevent the nanoparticles from aggregation during the preparation process. Transmission electron micrographs confirm that both silver nanoparticles and core-shell nanoparticles are regular spheres with the sizes in the range of 5-15 nm and 15-25 nm, respectively. The X-ray diffraction analysis reveals the face-centered cubic geometry of silver nanoparticles. The as-prepared nanoparticles were also characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. In addition, antimicrobial activities against E. coli and S. aureus were studied and the results show that both silver nanoparticles and core-shell nanoparticles possess excellent antimicrobial activities. The antimicrobial mechanism of the as-prepared nanoparticles was discussed.

Laser ablation synthesis of monodispersed magnetic alloy nanoparticles

International Nuclear Information System (INIS)

Seto, Takafumi; Koga, Kenji; Akinaga, Hiroyuki; Takano, Fumiyoshi; Orii, Takaaki; Hirasawa, Makoto

2006-01-01

Monodispersed CoPt alloy nanoparticles were synthesized by a pulsed laser ablation (PLA) technique coupled with a low-pressure operating differential mobility analyzer (LP-DMA). The CoPt alloy nanoparticles were generated by laser ablating a solid Co-Pt target. In CoPt alloy nanoparticles synthesized from a target with a Co composition of 75 at%, the nanoparticle surfaces were covered by an oxide layer and exhibited a core-shell structure. In contrast, no shell was observed in particles generated from a target with a Co:Pt ratio of 50:50 at%. According to an EDX analysis, the compositions of the individual nanoparticles were almost the same as that of the target material. Finally, the magnetic hysteresis loops of the CoPt alloy nanoparticles exhibited ferromagnetism

Laser ablation synthesis of monodispersed magnetic alloy nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Seto, Takafumi, E-mail: t.seto@aist.go.jp; Koga, Kenji; Akinaga, Hiroyuki; Takano, Fumiyoshi; Orii, Takaaki; Hirasawa, Makoto [National Institute of Advanced Industrial Science and Technology (AIST), Research Consortium for Synthetic Nano-Function Materials Project (SYNAF) (Japan)

2006-08-15

Monodispersed CoPt alloy nanoparticles were synthesized by a pulsed laser ablation (PLA) technique coupled with a low-pressure operating differential mobility analyzer (LP-DMA). The CoPt alloy nanoparticles were generated by laser ablating a solid Co-Pt target. In CoPt alloy nanoparticles synthesized from a target with a Co composition of 75 at%, the nanoparticle surfaces were covered by an oxide layer and exhibited a core-shell structure. In contrast, no shell was observed in particles generated from a target with a Co:Pt ratio of 50:50 at%. According to an EDX analysis, the compositions of the individual nanoparticles were almost the same as that of the target material. Finally, the magnetic hysteresis loops of the CoPt alloy nanoparticles exhibited ferromagnetism.

Green synthesis and antimicrobial activity of monodisperse silver nanoparticles synthesized using Ginkgo Biloba leaf extract

Science.gov (United States)

Ren, Yan-yu; Yang, Hui; Wang, Tao; Wang, Chuang

2016-11-01

Various parts of plants can be used as a raw material for the synthesis of nanoparticles, which is eco-friendly way and does not involve any harmful chemicals. In this project, Ginkgo biloba leaf, an abundantly available medicinal plant in China, was for the first time adopted as a reducing and stabilizing agent to synthesize smaller sized and stable silver nanoparticles (AgNPs). To improve the quality of AgNPs, the reduction was accelerated by changing the concentrations of initial Ag+ (0.02, 0.04, 0.06 and 0.08 mol/L) of the reaction mixture consisting of silver nitrate solution (AgNO3) and Ginkgo biloba leaf extract. At pH = 8 and lower AgNO3 concentration (0.02 mol/L), a colloid consisting of well-dispersed spherical nanoparticles was obtained. The synthesized nanocrystals were successfully characterized by UV-vis and XRD. TEM images revealed the size of the spherical AgNPs ranged between 10-16 nm. FTIR analysis revealed that biological macromolecules with groups of sbnd NH2, sbnd OH, and others were distributed on the surface of the nanoparticles. The biosynthesized AgNPs exhibited good antibacterial activities against gram-negative bacteria and gram-positive bacteria. Compared to traditional chemical methods, Ginkgo biloba leaf extract provides an easy green synthetical way. It is anticipated that the biosynthesized AgNPs can be used in areas such as cosmetics, foods and medical applications.

Cellular oxido-reductive proteins of Chlamydomonas reinhardtii control the biosynthesis of silver nanoparticles

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Barwal Indu

2011-12-01

Full Text Available Abstract Background Elucidation of molecular mechanism of silver nanoparticles (SNPs biosynthesis is important to control its size, shape and monodispersity. The evaluation of molecular mechanism of biosynthesis of SNPs is of prime importance for the commercialization and methodology development for controlling the shape and size (uniform distribution of SNPs. The unicellular algae Chlamydomonas reinhardtii was exploited as a model system to elucidate the role of cellular proteins in SNPs biosynthesis. Results The C. reinhardtii cell free extract (in vitro and in vivo cells mediated synthesis of silver nanoparticles reveals SNPs of size range 5 ± 1 to 15 ± 2 nm and 5 ± 1 to 35 ± 5 nm respectively. In vivo biosynthesized SNPs were localized in the peripheral cytoplasm and at one side of flagella root, the site of pathway of ATP transport and its synthesis related enzymes. This provides an evidence for the involvement of oxidoreductive proteins in biosynthesis and stabilization of SNPs. Alteration in size distribution and decrease of synthesis rate of SNPs in protein-depleted fractions confirmed the involvement of cellular proteins in SNPs biosynthesis. Spectroscopic and SDS-PAGE analysis indicate the association of various proteins on C. reinhardtii mediated in vivo and in vitro biosynthesized SNPs. We have identified various cellular proteins associated with biosynthesized (in vivo and in vitro SNPs by using MALDI-MS-MS, like ATP synthase, superoxide dismutase, carbonic anhydrase, ferredoxin-NADP+ reductase, histone etc. However, these proteins were not associated on the incubation of pre-synthesized silver nanoparticles in vitro. Conclusion Present study provides the indication of involvement of molecular machinery and various cellular proteins in the biosynthesis of silver nanoparticles. In this report, the study is mainly focused towards understanding the role of diverse cellular protein in the synthesis and capping of silver

Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

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Wen Zhu

2013-12-01

Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

The Anti-Fasciolasis Properties of Silver Nanoparticles Produced by Trichoderma harzianum and Their Improvement of the Anti-Fasciolasis Drug Triclabendazole

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AbdelElah A. Banaja

2013-11-01

Full Text Available Recently, new strains of Fasciola demonstrated drug resistance, which increased the need for new drugs or improvement of the present drugs. Nanotechnology is expected to open some new opportunities to fight and prevent diseases using an atomic scale tailoring of materials. The ability to uncover the structure and function of biosystems at the nanoscale, stimulates research leading to improvement in biology, biotechnology, medicine and healthcare. The size of nanomaterials is similar to that of most biological molecules and structures; therefore, nanomaterials can be useful for both in vivo and in vitro biomedical research and applications. Therefore, this work aimed to isolate fungal strains from Taif soil samples, which have the ability to synthesize silver nanoparticles. The fungus Trichoderma harzianum, when challenged with silver nitrate solution, accumulated silver nanoparticles (AgNBs on the surface of its cell wall in 72 h. These nanoparticles, dislodged by ultrasonication, showed an absorption peak at 420 nm in a UV-visible spectrum, corresponding to the plasmon resonance of silver nanoparticles. The transmission electron micrographs of dislodged nanoparticles in aqueous solution showed the production of reasonably monodisperse silver nanoparticles (average particle size: 4.66 nm by the fungus. The percentage of non hatching eggs treated with the Triclabendazole drug was 69.67%, while this percentage increased to 89.67% in combination with drug and AgNPs.

Rapid synthesis of gold and silver nanoparticles using tryptone as a reducing and capping agent

Science.gov (United States)

Mehta, Sourabh M.; Sequeira, Marilyn P.; Muthurajana, Harries; D'Souza, Jacinta S.

2018-02-01

Due to its eco-friendliness, recent times have seen an immense interest in the green synthesis of metallic nanoparticles. We present here, a protocol for the rapid and cheap synthesis of Au and Ag nanoparticles (NPs) using 1 mg/ml tryptone (trypsinized casein) as a reducing and capping agent. These nanoparticles are spherical, 10 nm in diameter and relatively monodispersed. The atoms of these NPs are arranged in face-centered cubic fashion. Further, when tested for their cytotoxic property against HeLa and VERO cell lines, gold nanoparticles were more lethal than silver nanoparticles, with a more or less similar trend observed against both Gram-positive and Gram-negative bacteria. On the other hand, the NPs were least cytotoxic against a unicellular alga, Chlamydomonas reinhardtii implying their eco-friendly property.

Green synthesis of silver nanoparticles: The reasons for and against Aspergillus parasiticus

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Maryam Moazeni

2014-09-01

Full Text Available Abstract Objective(s: The enzymatic activity of fungi has recently inspired the scientists with re-explore the fungi as potential biofactories rather than the causing agents of humans and plants infections. In very recent years, fungi are considered as worthy, applicable and available candidates for synthesis of smaller gold, silver and other nano-sized particles. Materials and Methods: A standard strain of Aspergillus parasiticus was grown on a liquid medium containing mineral salt. The cell-free filtrate of the culture was then obtained and subjected to synthesize SNPs while expose with 1mM of AgNO 3. Further characterization of synthesized SNPs was performed afterward. In addition, antifungal activity of synthesized SNPs was evaluated against a standard strain of Candida albicans. The reduction of Ag+ ions to metal nanoparticles was investigated virtually by tracing the color of the solution which turned into reddish-brown after 72h. Results: The UV-vis spectra demonstrated a broad peak centering at 400nm which corresponds to the particle size much less than 70nm. The results of TEM demonstrated that the particles were formed fairly uniform, spherical, and small in size with almost 90% in 5-30nm range. The zeta potential of silver nanoparticles was negative and equal to -15.0 which meets the quality and suggested that there was not much aggression. Silver nanoparticles synthesized by A. parasiticus showed antifungal activity against yeast strain tested an d exhibited MIC value of 4 μg/mL. Conclusion: The filamentous fungus, A. parasiticus has successfully demonstrated potential for extra cellular synthesis of fairly monodispersed, tiny silver nanoparticles.

Eco-Friendly Phyto-Synthesis of Silver Nanoparticles Using Jatropha Seedcake Extract

International Nuclear Information System (INIS)

Bose, Anjali; Keharia, Haresh; Deshpande, M. P.

2013-01-01

Phytosynthesis of metal nanoparticles is gaining importance due to their biocompatibility, low toxicity and eco-friendly nature. In the present study, an aqueous extract of Jatropha seedcake (JSC) is assessed as a reducing and stabilizing agent for the synthesis of silver nanoparticles (AgNPs). The maximum reduction of silver ions occur when 1 mM AgNO 3 solution is treated with 0.1 volume fraction of JSC extract in boiling water bath for 10 min. The synthesis of AgNPs is monitored by the excitation of surface plasmon resonance using UV-vis spectrophotometry. The AgNPs are found to be mono-dispersed, spherical with average particle size of 10.48 ± 74 nm when analyzed by transmission electron microscopy. The selected area electron diffraction (SAED) ring pattern indicated the polycrystalline nature of the AgNPs. The x-ray diffraction data further confirm the presence of characteristic (111), (200), (220), (311) and (222) diffraction planes of face centered cubic structure, and the calculated lattice parameter comes out to be 4.083 Å. FTIR analysis reveals the involvement of proteins and phenols in reduction and stabilization of nanoparticles. The synthesized AgNPs have significant antibacterial action on both the Gram positive and negative bacteria

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

Science.gov (United States)

Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li, Zi-An; Farle, Michael; Köller, Manfred; Epple, Matthias

2012-10-01

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 μg mL-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.

Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

International Nuclear Information System (INIS)

Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi

2015-01-01

The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO 3 aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi

Photochemical Study of Silver Nanoparticles Formed from the Reduction of Silver Ions by Humic Acid

Science.gov (United States)

Leslie, Renee M.

This study focuses on the ability of silver ions and humic acid to form silver nanoparticles in the presence of UV and visible light. Silver nanoparticles have a number of industrial applications due primarily to their antimicrobial properties, but these properties pose an environmental threat. Silver nanoparticles can directly disrupt sensitive ecosystems by harming bacteria. Consumption of silver nanoparticles results in silver ions and silver nanoparticles entering waterways; the presence of silver ions raises the question of whether nanoparticles can reform in environmental waters. As our data show, silver nanoparticles can form from the reduction of silver ions by humic acid after irradiation with UV and visible light. In order to better understand the mechanism of these naturally synthesized silver nanoparticles, we investigated the effects of reactant concentration, experimental conditions and presence of ions/reactive species. We monitored silver nanoparticle growth with UV-visible spectroscopy. The evolution in time of nanoparticle size was monitored by dynamic light scattering (DLS).

The role of tannic acid and sodium citrate in the synthesis of silver nanoparticles

Science.gov (United States)

Ranoszek-Soliwoda, Katarzyna; Tomaszewska, Emilia; Socha, Ewelina; Krzyczmonik, Pawel; Ignaczak, Anna; Orlowski, Piotr; Krzyzowska, Małgorzata; Celichowski, Grzegorz; Grobelny, Jaroslaw

2017-08-01

We describe herein the significance of a sodium citrate and tannic acid mixture in the synthesis of spherical silver nanoparticles (AgNPs). Monodisperse AgNPs were synthesized via reduction of silver nitrate using a mixture of two chemical agents: sodium citrate and tannic acid. The shape, size and size distribution of silver particles were determined by UV-Vis spectroscopy, dynamic light scattering (DLS) and scanning transmission electron microscopy (STEM). Special attention is given to understanding and experimentally confirming the exact role of the reagents (sodium citrate and tannic acid present in the reaction mixture) in AgNP synthesis. The oxidation and reduction potentials of silver, tannic acid and sodium citrate in their mixtures were determined using cyclic voltammetry. Possible structures of tannic acid and its adducts with citric acid were investigated in aqueous solution by performing computer simulations in conjunction with the semi-empirical PM7 method. The lowest energy structures found from the preliminary conformational search are shown, and the strength of the interaction between the two molecules was calculated. The compounds present on the surface of the AgNPs were identified using FT-IR spectroscopy, and the results are compared with the IR spectrum of tannic acid theoretically calculated using PM6 and PM7 methods. The obtained results clearly indicate that the combined use of sodium citrate and tannic acid produces monodisperse spherical AgNPs, as it allows control of the nucleation, growth and stabilization of the synthesis process. [Figure not available: see fulltext.

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.

Biological synthesis of silver nanoparticles

International Nuclear Information System (INIS)

Maliszewska, I; Szewczyk, K; Waszak, K

2009-01-01

Fungus-mediated synthesis of silver nanoparticles is reported. The nanosilver was formed in contact with the cell-free filtrate of Penicillium strain studied. The nanoparticles were characterized by means of the UV-Vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The synthesized nanosilver showed a absorbed maximum at 425 nm in the visible region. The SEM characterization of the fungus cells treated with silver nitrite indicated that the protein might be responsible for the reduction of silver ions. Transmission electron microscopy (TEM) micrograph showed formation of silver nanoparticles in the range of 10-100 nm.

Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

Energy Technology Data Exchange (ETDEWEB)

Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi, E-mail: yangdz@mail.buct.edu.cn

2015-06-01

The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO{sub 3} aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi.

Green synthesis of silver nanoparticles and silver colloidal solutions

International Nuclear Information System (INIS)

Nguyen Thi Phuong Phong; Ngo Hoang Minh; Ngo Vo Ke Thanh; Dang Mau Chien

2009-01-01

In this paper, silver colloidal solutions have been synthesized rapidly in green conditions by using microwave irradiation and non-toxic chemistry substances (acid oxalic, silver nitrate, polyvinyl pyrolidone (PVP; Mw = 55 000)). The particle size and morphology of these solutions can be controlled by altering several factors like the time, the power of microwave exposure, and the ratio of silver oxalate and PVP etc. The silver nanoparticles were fabricated by thermal decomposition of silver oxalate. The synthesized silver colloidal solutions and silver nanoparticles were characterized by several analytical techniques like UV- VIS, XRD, TEM, FESEM/EDS and ICP-AAS studies. Finally, we used the synthesized silver colloidal solutions for antibacterial purpose. The obtained results showed that the synthesized silver colloidal solutions, even at very low concentrations, have highly efficient anti-bacterial property.

One-pot facile green synthesis of biocidal silver nanoparticles

Science.gov (United States)

Nudrat Hazarika, Shabiha; Gupta, Kuldeep; Shamin, Khan Naseem Ahmed Mohammed; Bhardwaj, Pushpender; Boruah, Ratan; Yadav, Kamlesh K.; Naglot, Ashok; Deb, P.; Mandal, M.; Doley, Robin; Veer, Vijay; Baruah, Indra; Namsa, Nima D.

2016-07-01

The plant root extract mediated green synthesis method produces monodispersed spherical shape silver nanoparticles (AgNPs) with a size range of 15-30 nm as analyzed by atomic force and transmission electron microscopy. The material showed potent antibacterial and antifungal properties. Synthesized AgNPs display a characteristic surface plasmon resonance peak at 420 nm in UV-Vis spectroscopy. X-ray diffractometer analysis revealed the crystalline and face-centered cubic geometry of in situ prepared AgNPs. Agar well diffusion and a colony forming unit assay demonstrated the potent biocidal activity of AgNPs against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas diminuta and Mycobacterium smegmatis. Intriguingly, the phytosynthesized AgNPs exhibited activity against pathogenic fungi, namely Trichophyton rubrum, Aspergillus versicolor and Candida albicans. Scanning electron microscopy observations indicated morphological changes in the bacterial cells incubated with silver nanoparticles. The genomic DNA isolated from the bacteria was incubated with an increasing concentration of AgNPs and the replication fidelity of 16S rDNA was observed by performing 18 and 35 cycles PCR. The replication efficiency of small (600 bp) and large (1500 bp) DNA fragments in the presence of AgNPs were compromised in a dose-dependent manner. The results suggest that the Thalictrum foliolosum root extract mediated synthesis of AgNPs could be used as a promising antimicrobial agent against clinical pathogens.

Silver Nanoparticles-graphene Oxide Nanocomposite for Antibacterial Purpose

International Nuclear Information System (INIS)

Chook, S.W.; Chia, C.H.; Sarani Zakaria; Mohd Khan Ayob; Chee, K.L.; Neoh, H.M.; Huang, N.M.

2011-01-01

Graphene oxide (GO) sheets, a single layer of carbon atoms which can be served as substrates for fabricating metallic nanoparticles-GO nano composites, have been used in this study The nanocomposite of silver nanoparticles and graphene oxide were produced via in-situ synthesis and with the aid of chitosan to investigate the formation of silver nanoparticles on the graphene oxide sheets. XRD and UV-Vis studies confirmed the formation of silver nanoparticles on GO sheets, while TEM and FESEM images presented the loading of silver nanoparticles on the GO sheets. The degree of loading and distribution of the silver nanoparticles on the graphene oxide were depended on the procedure during the formation of silver nanoparticles. The nano composites can be potentially used in food packaging and biomedical applications. (author)

Silver nanoparticle production by the fungus Fusarium oxysporum: nanoparticle characterisation and analysis of antifungal activity against pathogenic yeasts

Directory of Open Access Journals (Sweden)

Kelly Ishida

2014-04-01

Full Text Available The microbial synthesis of nanoparticles is a green chemistry approach that combines nanotechnology and microbial biotechnology. The aim of this study was to obtain silver nanoparticles (SNPs using aqueous extract from the filamentous fungus Fusarium oxysporum as an alternative to chemical procedures and to evaluate its antifungal activity. SNPs production increased in a concentration-dependent way up to 1 mM silver nitrate until 30 days of reaction. Monodispersed and spherical SNPs were predominantly produced. After 60 days, it was possible to observe degenerated SNPs with in additional needle morphology. The SNPs showed a high antifungal activity against Candida and Cryptococcus , with minimum inhibitory concentration values ≤ 1.68 µg/mL for both genera. Morphological alterations of Cryptococcus neoformans treated with SNPs were observed such as disruption of the cell wall and cytoplasmic membrane and lost of the cytoplasm content. This work revealed that SNPs can be easily produced by F. oxysporum aqueous extracts and may be a feasible, low-cost, environmentally friendly method for generating stable and uniformly sized SNPs. Finally, we have demonstrated that these SNPs are active against pathogenic fungi, such as Candida and Cryptococcus .

Green synthesis of silver nanoparticles using tannins

Science.gov (United States)

Raja, Pandian Bothi; Rahim, Afidah Abdul; Qureshi, Ahmad Kaleem; Awang, Khalijah

2014-09-01

Colloidal silver nanoparticles were prepared by rapid green synthesis using different tannin sources as reducing agent viz. chestnut (CN), mangrove (MG) and quebracho (QB). The aqueous silver ions when exposed to CN, MG and QB tannins were reduced which resulted in formation of silver nanoparticles. The resultant silver nanoparticles were characterized using UV-Visible, X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), and transmission electron microscopy (TEM) techniques. Furthermore, the possible mechanism of nanoparticles synthesis was also derived using FT-IR analysis. Spectroscopy analysis revealed that the synthesized nanoparticles were within 30 to 75 nm in size, while XRD results showed that nanoparticles formed were crystalline with face centered cubic geometry.

Silver distribution and release from an antimicrobial denture base resin containing silver colloidal nanoparticles.

Science.gov (United States)

Monteiro, Douglas Roberto; Gorup, Luiz Fernando; Takamiya, Aline Satie; de Camargo, Emerson Rodrigues; Filho, Adhemar Colla Ruvolo; Barbosa, Debora Barros

2012-01-01

The aim of this study was to evaluate a denture base resin containing silver colloidal nanoparticles through morphological analysis to check the distribution and dispersion of these particles in the polymer and by testing the silver release in deionized water at different time periods. A Lucitone 550 denture resin was used, and silver nanoparticles were synthesized by reduction of silver nitrate with sodium citrate. The acrylic resin was prepared in accordance with the manufacturers' instructions, and silver nanoparticle suspension was added to the acrylic resin monomer in different concentrations (0.05, 0.5, and 5 vol% silver colloidal). Controls devoid of silver nanoparticles were included. The specimens were stored in deionized water at 37°C for 7, 15, 30, 60, and 120 days, and each solution was analyzed using atomic absorption spectroscopy. Silver was not detected in deionized water regardless of the silver nanoparticles added to the resin and of the storage period. Micrographs showed that with lower concentrations, the distribution of silver nanoparticles was reduced, whereas their dispersion was improved in the polymer. Moreover, after 120 days of storage, nanoparticles were mainly located on the surface of the nanocomposite specimens. Incorporation of silver nanoparticles in the acrylic resin was evidenced. Moreover, silver was not detected by the detection limit of the atomic absorption spectrophotometer used in this study, even after 120 days of storage in deionized water. Silver nanoparticles are incorporated in the PMMA denture resin to attain an effective antimicrobial material to help control common infections involving oral mucosal tissues in complete denture wearers. © 2011 by the American College of Prosthodontists.

Preparation of silver nanoparticles at low temperature

Energy Technology Data Exchange (ETDEWEB)

Mishra, Mini, E-mail: mishramini5@gmail.com [Centre of Environmental Science, Department of Botany, University of Allahabad, Allahabad, U.P. (India); Chauhan, Pratima, E-mail: mangu167@yahoo.co.in [Department of Physics, University of Allahabad, Allahabad U.P. (India)

2016-04-13

Silver from ancient time is used as antimicrobial agent in the bulk form but now with the advancement in nanotechnology silver in the form of nanoparticles shown potential effect against microbes which make us easy to fight with many diseases plants and animals. In this work silver nanoparticles were synthesized by chemical routes using sodium borohydride as reducing agent at low temperature. The particles were characterized through UV-Visible spectroscopy as well as X-Ray Diffraction. The UV-visible spectra of silver nanoparticles exhibited absorption at 425 cm; the crystallite size of the particles is between 19nm to 39nm. EDAX graph shows two peaks of silver and oxygen. Water absorbed by silver nanoparticles was removed by the calcinations.

Preparation of silver nanoparticles at low temperature

International Nuclear Information System (INIS)

Mishra, Mini; Chauhan, Pratima

2016-01-01

Silver from ancient time is used as antimicrobial agent in the bulk form but now with the advancement in nanotechnology silver in the form of nanoparticles shown potential effect against microbes which make us easy to fight with many diseases plants and animals. In this work silver nanoparticles were synthesized by chemical routes using sodium borohydride as reducing agent at low temperature. The particles were characterized through UV-Visible spectroscopy as well as X-Ray Diffraction. The UV-visible spectra of silver nanoparticles exhibited absorption at 425 cm; the crystallite size of the particles is between 19nm to 39nm. EDAX graph shows two peaks of silver and oxygen. Water absorbed by silver nanoparticles was removed by the calcinations.

Completely green synthesis of dextrose reduced silver nanoparticles, its antimicrobial and sensing properties.

Science.gov (United States)

Mohan, Sneha; Oluwafemi, Oluwatobi S; George, Soney C; Jayachandran, V P; Lewu, Francis B; Songca, Sandile P; Kalarikkal, Nandakumar; Thomas, Sabu

2014-06-15

We herein report the green synthesis of highly monodispersed, water soluble, stable and smaller sized dextrose reduced gelatin capped-silver nanoparticles (Ag-NPs) via an eco-friendly, completely green method. The synthesis involves the use of silver nitrate, gelatin, dextrose and water as the silver precursor, stabilizing agent, reducing agent and solvent respectively. By varying the reaction time, the temporal evolution of the growth, optical, antimicrobial and sensing properties of the as-synthesised Ag-NPs were investigated. The nanoparticles were characterized using UV-vis absorption spectroscopy, Fourier transform infra-red spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HR-TEM). The absorption maxima of the as-synthesized materials at different reaction time showed characteristic silver surface plasmon resonance (SPR) peak. The as-synthesised Ag-NPs show better antibacterial efficacy than the antibiotics; ciproflaxin and imipenem against Pseudomonas aeruginosa with minimum inhibition concentration (MIC) of 6 μg/mL, and better efficacy than imipenem against Escherichia coli with MIC of 10 μg/mL. The minimum bactericidal concentration (MBC) of the as-synthesised Ag-NPs is 12.5 μg/mL. The sensitivity of the dextrose reduced gelatin-capped Ag-NPs towards hydrogen peroxide indicated that the sensor has a very good sensitivity and a linear response over wide concentration range of 10(-1)-10(-6)M H2O2. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis and characterization of silver nanoparticles by sol-gel route from silver nitrate

International Nuclear Information System (INIS)

Morales, Jorge; Moran, Jose; Quintana, Maria; Estrada, Walter

2009-01-01

Silver nanoparticles colloids have been synthesized by sol-gel method. This synthesis consists in silver nitrate reduction by ethylene glycol in a process called polyol. The growth of the nanoparticles have been controlled by the steric stabilization of the colloid with polyvinylpyrrolidone (PVP, M w = 40 000). The silver nanoparticle size and structure was depending on the control of parameters such as: molar concentrations ratio of silver nitrate and PVP, temperature of reaction and the reflux time. Colloids have been characterized by UV-vis spectroscopy in the range from 300 to 1000 nm. The results show that the typical peak of surface plasmon resonance is formed at 400-450 nm indicating the formation of silver nanoparticles. The presences of silver nanoparticles of spherical shape with size among 20-40 nm were observed by transmission electronic microscopy (TEM). Electron diffraction patterns confirmed that synthesized colloids contain metallic silver with a crystal structure face centered cubic FCC. (author)

Plasmonic characterization of photo-induced silver nanoparticles extracted from silver halide based TEM film

Energy Technology Data Exchange (ETDEWEB)

Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Rai, V. N.; Srivastava, A. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India); Varshney, G. K. [Laser Bio-medical Applications & Instrumentation Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India)

2016-05-23

The plasmonic responses of silver nanoparticles extracted from silver halide based electron microscope film are investigated. Photo-reduction process is carried out to convert the silver halide grains into the metallic silver. The centrifuge technique is used for separating the silver nanoparticles from the residual solution. Morphological study performed by field emission scanning electron microscope (FESEM) shows that all the nanoparticles have an average diameter of ~120 nm with a high degree of mono dispersion in size. The localized surface plasmon resonance (LSPR) absorption peak at ~537 nm confirms the presence of large size silver nanoparticles.

Antimicrobial effects of zinc oxide nanoparticles modified with silver

International Nuclear Information System (INIS)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes

2016-01-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Antimicrobial effects of zinc oxide nanoparticles modified with silver

Energy Technology Data Exchange (ETDEWEB)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes, E-mail: rayssasouza.net@gmail.com [Universidade Federal de Goias (UFG), Goiania (Brazil)

2016-07-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Preparation and Characterization of Silver Liquid Thin Films for Magnetic Fluid Deformable Mirror

Directory of Open Access Journals (Sweden)

Lianchao Zhang

2015-01-01

Full Text Available Silver liquid thin film, formed by silver nanoparticles stacking and spreading on the surface of the liquid, is one of the important parts of magnetic fluid deformable mirror. First, silver nanoparticles were prepared by liquid phase chemical reduction method using sodium citrate as reducing agent and stabilizer and silver nitrate as precursor. Characterization of silver nanoparticles was studied using X-ray diffractometer, UV-vis spectrophotometer, and transmission electron microscope (TEM. The results showed that silver nanoparticles are spherical and have a good monodispersity. Additionally, the effect of the reaction conditions on the particle size of silver is obvious. And then silver liquid thin films were prepared by oil-water two-phase interface technology using as-synthesized silver nanoparticles. Properties of the film were investigated using different technology. The results showed that the film has good reflectivity and the particle size has a great influence on the reflectivity of the films. SEM photos showed that the liquid film is composed of multilayer silver nanoparticles. In addition, stability of the film was studied. The results showed that after being stored for 8 days under natural conditions, the gloss and reflectivity of the film start to decrease.

Toxicity of silver nanoparticles in monocytes and keratinocytes

DEFF Research Database (Denmark)

Orłowski, Piotr; Krzyzowska, Malgorzata; Winnicka, Anna

2012-01-01

Silver nanoparticles are of interest to be used as antimicrobial agents in wound dressings and coatings in medical devices, but potential adverse effects have been reported in the literature. The possible local inflammatory response to silver nanoparticles and the role of cell death in determining...... these effects are largely unknown. Effects of the mixture of silver nanoparticles of different sizes were compared in in vitro assays for cytotoxicity, caspase-1 and caspase-9 activity and bax expression. In all tested concentrations, silver nanoparticles were more toxic for RAW 264.7 monocytes than for 291.03C...... keratinocytes and induced significant caspase-1 activity and necrotic cell death. In keratinocytes, more significantly than in macrophages, silver nanoparticles led to increase of caspase-9 activity and apoptosis. These results indicate that effects of silver nanoparticles depend on the type of exposed cells...

Rapid Synthesis of Highly Monodisperse Au x Ag 1− x Alloy Nanoparticles via a Half-Seeding Approach

KAUST Repository

Chng, Ting Ting

2011-05-03

Gold-silver alloy AuxAg1-x is an important class of functional materials promising new applications across a wide array of technological fields. In this paper, we report a fast and facile synthetic protocol for preparation of highly monodisperse AuxAg1-x alloy nanoparticles in the size range of 3-6 nm. The precursors employed in this work are M(I)-alkanethiolates (M = Au and Ag), which can be easily prepared by mixing common chemicals such as HAuCl4 or AgNO3 with alkanethiols at room temperature. In this half-seeding approach, one of the M(I)-alkanethiolates is first heated and reduced in oleylamine solvent, and freshly formed metal clusters will then act as premature seeds on which both the first and second metals (from M(I)-alkanethiolates, M = Au and Ag) can grow accordingly without additional nucleation and thus achieve high monodispersity for product alloy nanoparticles. Unlike in other prevailing methods, both Au and Ag elements present in these solid precursors are in the same monovalent state and have identical supramolecular structures, which may lead to a more homogeneous reduction and complete interdiffusion at elevated reaction temperatures. When the M(I)-alkanethiolates are reduced to metallic forms, the detached alkanethiolate ligands will serve as capping agent to control the growth. More importantly, composition, particle size, and optical properties of AuxAg1-x alloy nanoparticles can be conveniently tuned with this approach. The optical limiting properties of the prepared particles have also been investigated at 532 and 1064 nm using 7 ns laser pulses, which reveals that the as-prepared alloy nanoparticles exhibit outstanding broadband optical limiting properties with low thresholds. © 2011 American Chemical Society.

Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres

Indian Academy of Sciences (India)

Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres. K C BARICK and D BAHADUR*. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay,. Mumbai 400 076, India. Abstract. The assembly of superparamagnetic Fe3O4 nanoparticles on submicroscopic SiO2 ...

Silver nanoparticles in X-ray biomedical applications

International Nuclear Information System (INIS)

Mattea, Facundo; Vedelago, José; Malano, Francisco; Gomez, Cesar; Strumia, Miriam C.

2017-01-01

The fluorescence of silver nanoparticles or ions can be used for detection and dose enhancement purposes in X-ray irradiation applications. This study is focused on the full integration of the chemical synthesis of silver nanoparticles suitable for dosimetric and radiological purposes with characteristics that can be exploited in radiotherapy and radiodiagnostic. A narrow size distribution and a compatible stabilizing agent is often desired in order to obtain homogeneous behaviors in nanoparticle suspension. With the method proposed in this study, nanoparticles ranging from 5 to 20 nm were obtained. The fluorescence of aqueous suspensions of silver nanoparticles has been measured experimentally and simulated with the Monte Carlo PENELOPE code for different silver concentrations and geometrical configurations. Finally, the feasibility of using these nanoparticles for the elaboration of Fricke gel dosimeters has been tested obtaining a dose enhancement when compared with the same material irradiated below the silver K-edge. - Highlights: • A method to compare NP's fluorescence in simulations and experiments was developed. • Silver nanoparticles suitable for typical dosimetry systems were synthesized. • Concentration and depth of a Ag doped volume was measured with X-ray fluorescence. • A feasibility test of Ag NPs in Fricke gel dosimetry was performed. • Good agreement between Monte Carlo simulations and experiments was obtained.

Silver nanoparticles: Synthesis methods, bio-applications and properties.

Science.gov (United States)

Abbasi, Elham; Milani, Morteza; Fekri Aval, Sedigheh; Kouhi, Mohammad; Akbarzadeh, Abolfazl; Tayefi Nasrabadi, Hamid; Nikasa, Parisa; Joo, San Woo; Hanifehpour, Younes; Nejati-Koshki, Kazem; Samiei, Mohammad

2016-01-01

Silver nanoparticles size makes wide range of new applications in various fields of industry. Synthesis of noble metal nanoparticles for applications such as catalysis, electronics, optics, environmental and biotechnology is an area of constant interest. Two main methods for Silver nanoparticles are the physical and chemical methods. The problem with these methods is absorption of toxic substances onto them. Green synthesis approaches overcome this limitation. Silver nanoparticles size makes wide range of new applications in various fields of industry. This article summarizes exclusively scalable techniques and focuses on strengths, respectively, limitations with respect to the biomedical applicability and regulatory requirements concerning silver nanoparticles.

Fabrication of monodisperse magnetic nanoparticles released in solution using a block copolymer template

Science.gov (United States)

Morcrette, Mélissa; Ortiz, Guillermo; Tallegas, Salomé; Joisten, Hélène; Tiron, Raluca; Baron, Thierry; Hou, Yanxia; Lequien, Stéphane; Bsiesy, Ahmad; Dieny, Bernard

2017-07-01

This paper describes a fabrication process of monodisperse magnetic nanoparticles released in solution, based on combined ‘top-down’ and ‘bottom-up’ approaches. The process involves the use of a self-assembled PS-PMMA block copolymer formed on a sacrificial layer. Such an approach was so far mostly explored for the preparation of patterned magnetic media for ultrahigh density magnetic storage. It is here extended to the preparation of released monodisperse nanoparticles for biomedical applications. A special sacrificial layer had to be developed compatible with the copolymer self-organization. The resulting nanoparticles exhibit very narrow size dispersion (≈7%) and can be good candidates as contrast agents for medical imaging i.e. magnetic resonance imaging or magnetic particle imaging. The approach provides a great freedom in the choice of the particles shapes and compositions. In particular, they can be made of biocompatible magnetic material.

Fabrication of monodisperse magnetic nanoparticles released in solution using a block copolymer template

International Nuclear Information System (INIS)

Morcrette, Mélissa; Ortiz, Guillermo; Joisten, Hélène; Dieny, Bernard; Tallegas, Salomé; Baron, Thierry; Bsiesy, Ahmad; Tiron, Raluca; Hou, Yanxia; Lequien, Stéphane

2017-01-01

This paper describes a fabrication process of monodisperse magnetic nanoparticles released in solution, based on combined ‘top-down’ and ‘bottom-up’ approaches. The process involves the use of a self-assembled PS-PMMA block copolymer formed on a sacrificial layer. Such an approach was so far mostly explored for the preparation of patterned magnetic media for ultrahigh density magnetic storage. It is here extended to the preparation of released monodisperse nanoparticles for biomedical applications. A special sacrificial layer had to be developed compatible with the copolymer self-organization. The resulting nanoparticles exhibit very narrow size dispersion (≈7%) and can be good candidates as contrast agents for medical imaging i.e. magnetic resonance imaging or magnetic particle imaging. The approach provides a great freedom in the choice of the particles shapes and compositions. In particular, they can be made of biocompatible magnetic material. (paper)

Biosynthesis of Silver Nanoparticles and Its Applications

International Nuclear Information System (INIS)

Firdhouse, M. J.; Lalitha, P.

2015-01-01

Silver nanoparticles possess unique properties which find myriad applications such as antimicrobial, anticancer, larvicidal, catalytic, and wound healing activities. Biogenic syntheses of silver nanoparticles using plants and their pharmacological and other potential applications are gaining momentum owing to its assured rewards. This critical review is aimed at providing an insight into the phyto mediated synthesis of silver nanoparticles, its significant applications in various fields, and characterization techniques involved.

Self-assembled silver nanoparticles monolayers on mica-AFM, SEM, and electrokinetic characteristics

International Nuclear Information System (INIS)

Oćwieja, Magdalena; Morga, Maria; Adamczyk, Zbigniew

2013-01-01

A monodisperse silver particle suspension was produced by a chemical reduction method in an aqueous medium using sodium citrate. The average particle size determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) was 28.5 nm. The DLS measurements confirmed that the suspension was stable for the ionic strength up to 3 × 10 −2 M NaCl. The electrophoretic mobility measurements revealed that the electrokinetic charge of particles was negative for pH range 3–10, assuming −50 e for pH = 9 and 0.01 M NaCl. Using the suspension, silver particle monolayers on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverage, quantitatively determined by AFM and SEM, was regulated within broad limits by adjusting the nanoparticle deposition time. This allowed one to uniquely express the zeta potential of silver monolayers, determined by the in situ streaming potential measurements, in terms of particle coverage. Such dependencies obtained for various ionic strengths and pH, were successfully interpreted in terms of the 3D electrokinetic model. A universal calibrating graph was produced in this way, enabling one to determine silver monolayer coverage from the measured value of the streaming potential. Our experimental data prove that it is feasible to produce uniform and stable silver particle monolayers of well-controlled coverage and defined electrokinetic properties.

Biosynthesis of silver nanoparticles synthesized by Aspergillus

Indian Academy of Sciences (India)

In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

Biosynthesis, characterization, and antimicrobial applications of silver nanoparticles.

Science.gov (United States)

Singh, Priyanka; Kim, Yeon Ju; Singh, Hina; Wang, Chao; Hwang, Kyu Hyon; Farh, Mohamed El-Agamy; Yang, Deok Chun

2015-01-01

In the present study, the strain Brevibacterium frigoritolerans DC2 was explored for the efficient and extracellular synthesis of silver nanoparticles. These biosynthesized silver nanoparticles were characterized by ultraviolet-visible spectrophotometry, which detected the formation of silver nanoparticles in the reaction mixture and showed a maximum absorbance at 420 nm. In addition, field emission transmission electron microscopy revealed the spherical shape of the nanoparticles. The dynamic light scattering results indicated the average particle size of the product was 97 nm with a 0.191 polydispersity index. Furthermore, the product was analyzed by energy dispersive X-ray spectroscopy, X-ray diffraction, and elemental mapping, which displayed the presence of elemental silver in the product. Moreover, on a medical platform, the product was checked against pathogenic microorganisms including Vibrio parahaemolyticus, Salmonella enterica, Bacillus anthracis, Bacillus cereus, Escherichia coli, and Candida albicans. The nanoparticles demonstrated antimicrobial activity against all of these pathogenic microorganisms. Additionally, the silver nanoparticles were evaluated for their combined effects with the commercial antibiotics lincomycin, oleandomycin, vancomycin, novobiocin, penicillin G, and rifampicin against these pathogenic microorganisms. These results indicated that the combination of antibiotics with biosynthesized silver nanoparticles enhanced the antimicrobial effects of antibiotics. Therefore, the current study is a demonstration of an efficient biological synthesis of silver nanoparticles by B. frigoritolerans DC2 and its effect on the enhancement of the antimicrobial efficacy of well-known commercial antibiotics.

Green synthesis and characterization of silver nanoparticles using Lantana camara leaf extract

Energy Technology Data Exchange (ETDEWEB)

Ajitha, B., E-mail: ajithabondu@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Ashok Kumar Reddy, Y. [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Sreedhara Reddy, P. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India)

2015-04-01

In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV–vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV–vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures. - Highlights: • Monodispersed AgNPs are synthesized using L. camara leaf extract. • The higher the L. camara content, the smaller the particle size. • Green synthesized AgNPs are found to be photoluminescent. • Size dependence of antibacterial activity is reported. • The nanoparticle stability is improved by leaf extract quantity.

Green synthesis and characterization of silver nanoparticles using Lantana camara leaf extract

International Nuclear Information System (INIS)

Ajitha, B.; Ashok Kumar Reddy, Y.; Sreedhara Reddy, P.

2015-01-01

In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV–vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV–vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures. - Highlights: • Monodispersed AgNPs are synthesized using L. camara leaf extract. • The higher the L. camara content, the smaller the particle size. • Green synthesized AgNPs are found to be photoluminescent. • Size dependence of antibacterial activity is reported. • The nanoparticle stability is improved by leaf extract quantity

Environmentally friendly synthesis of highly monodisperse biocompatible gold nanoparticles with urchin-like shape.

Science.gov (United States)

Lu, Lehui; Ai, Kelong; Ozaki, Yukihiro

2008-02-05

We report a facile and environmentally friendly strategy for high-yield synthesis of highly monodisperse gold nanoparticles with urchin-like shape. A simple protein, gelatin, was first used for the control over shape and orientation of the gold nanoparticles. These nanoparticles, ready to use for biological systems, are promising in the optical imaging-based disease diagnostics and therapy because of their tunable surface plasmon resonance (SPR) and excellent surface-enhanced Raman scattering (SERS) activity.

Biosynthesis and structural characterization of silver nanoparticles from bacterial isolates

International Nuclear Information System (INIS)

Zaki, Sahar; El Kady, M.F.; Abd-El-Haleem, Desouky

2011-01-01

Graphical abstract: In this study five bacterial isolates belong to different genera were found to be able to biosynthesize silver nanoparticles. Biosynthesis and spectral characterization are reported here. Highlights: → About 300 bacterial isolates were screened for their ability to produce nanosilvers → Five of them were potential candidates for synthesis of silver nanoparticles → Production of silver nanoparticles was examined using UV-Vis, XRD, SEM and EDS. → The presence of nanoparticles with all five bacterial isolates was confirmed. -- Abstract: This study aimed to develop a green process for biosynthesis of silver nanomaterials by some Egyptian bacterial isolates. This target was achieved by screening an in-house culture collection consists of 300 bacterial isolates for silver nanoparticle formation. Through screening process, it was observed that strains belonging to Escherichia coli (S30, S78), Bacillus megaterium (S52), Acinetobacter sp. (S7) and Stenotrophomonas maltophilia (S54) were potential candidates for synthesis of silver nanoparticles. The extracellular production of silver nanoparticles by positive isolates was investigated by UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results demonstrated that UV-visible spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy micrograph showed formation of silver nanoparticles in the range of 15-50 nm. XRD-spectrum of the silver nanoparticles exhibited 2θ values corresponding to the silver nanocrystal that produce in hexagonal and cubic crystal configurations with different plane of orientation. In addition, the signals of the silver atoms were observed by EDS-spectrum analysis that confirms the presence of silver nanoparticles (AgNPs) in all positive

In-site synthesis of monodisperse, oleylamine-capped Ag nanoparticles through microemulsion approach

Science.gov (United States)

Chen, Shun; Ju, Yanyun; Guo, Yi; Xiong, Chuanxi; Dong, Lijie

2017-03-01

Ag NPs were in-site synthesized through microemulsion method by reducing silver acetate with oleylamine-mediated at 70 °C with highly monodisperse and narrow size from 10 to 20 nm. The synthesis of Ag NPs was aided by oleylamine and the role of oleylamine was researched. This in-site synthesis approach to Ag NPs was reproducibility and high yield more than 80% with stable store about 6 months.

Tailoring silver nanoparticle construction using dendrimer templated silica networks

International Nuclear Information System (INIS)

Liu Xiaojun; Kakkar, Ashok

2008-01-01

We have examined the role of the internal environment of dendrimer templated silica networks in tailoring the construction of silver nanoparticle assemblies. Silica networks from which 3,5-dihydroxybenzyl alcohol based dendrimer templates have been completely removed, slowly wet with an aqueous solution of silver acetate. The latter then reacts with internal silica silanol groups, leading to chemisorption of silver ions, followed by the growth of silver oxide nanoparticles. Silica network constructed using generation 4 dendrimer contains residual dendrimer template, and mixes with aqueous silver acetate solution easily. Upon chemisorption, silver ions get photolytically reduced to silver metal under a stabilizing dendrimer environment, leading to the formation of silver metal nanoparticles

Hyaluronan- and heparin-reduced silver nanoparticles with antimicrobial properties

Science.gov (United States)

Kemp, Melissa M; Kumar, Ashavani; Clement, Dylan; Ajayan, Pulickel; Mousa, Shaker

2009-01-01

Aims Silver nanoparticles exhibit unique antibacterial properties that make these ideal candidates for biological and medical applications. We utilized a clean method involving a single synthetic step to prepare silver nanoparticles that exhibit antimicrobial activity. Materials & methods These nanoparticles were prepared by reducing silver nitrate with diaminopyridinylated heparin (DAPHP) and hyaluronan (HA) polysaccharides and tested for their efficacy in inhibiting microbial growth. Results & discussion The resulting silver nanoparticles exhibit potent antimicrobial activity against Staphylococcus aureus and modest activity against Escherichia coli. Silver–HA showed greater antimicrobial activity than silver–DAPHP, while silver–glucose nanoparticles exhibited very weak antimicrobial activity. Neither HA nor DAPHP showed activity against S. aureus or E. coli. Conclusion These results suggest that DAPHP and HA silver nanoparticles have potential in antimicrobial therapeutic applications. PMID:19505245

Use of a silver ion selective electrode to assess mechanisms responsible for biological effects of silver nanoparticles

International Nuclear Information System (INIS)

Koch, Marcus; Kiefer, Silke; Cavelius, Christian; Kraegeloh, Annette

2012-01-01

For a detailed analysis of the biological effects of silver nanoparticles, discrimination between effects related to the nano-scale size of the particles and effects of released silver ions is required. Silver ions are either present in the initial particle dispersion or released by the nanoparticles over time. The aim of this study is to monitor the free silver ion activity {Ag + } in the presence of silver nanoparticles using a silver ion selective electrode. Therefore, silver in the form of silver nanoparticles, 4.2 ± 1.4 nm and 2–30 nm in size, or silver nitrate was added to cell culture media in the absence or presence of A549 cells as a model for human type II alveolar epithelial cells. The free silver ion activity measured after the addition of silver nanoparticles was determined by the initial ionic silver content. The p {Ag + } values indicated that the cell culture media decrease the free silver ion activity due to binding of silver ions by constituents of the media. In the presence of A549 cells, the free silver ion activity was further reduced. The morphology of A549 cells, cultivated in DME medium containing 9.1% (v/v) FBS, was affected by adding AgNO 3 at concentrations of ≥30 μM after 24 h. In comparison, silver nanoparticles up to a concentration of 200 μM Ag did not affect cellular morphology. Our experiments indicate that the effect of silver nanoparticles is mainly mediated by silver ions. An effect of silver on cellular morphology was observed at p {Ag + } ≤ 9.2.

Complex conductivity response to silver nanoparticles in ...

Science.gov (United States)

The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research needs include knowledge and methods for their detection, characterization, fate, and transport. Specifically, techniques available for the direct detection and quantification of their fate and transport in the environment are limited. Their small size, high surface area to volume ratio, interfacial, and electrical properties make metallic nanoparticles, such as silver nanoparticles, good targets for detection using electrical geophysical techniques. Here we measured the complex conductivity response to silver nanoparticles in sand columns under varying moisture conditions (0–30%), nanoparticle concentrations (0–10 mg/g), lithology (presence of clay), pore water salinity (0.0275 and 0.1000 S/m), and particle size (35, 90–210 and 1500–2500 nm). Based on the Cole-Cole relaxation models we obtained the chargeability and the time constant. We demonstrate that complex conductivity can detect silver nanoparticles in porous media with the response enhanced by higher concentrations of silver nanoparticles, moisture content, ionic strength, clay content and particle diameter. Quantification of the volumetric silver nanoparticles content in the porous media can also be obtained from complex co

Antimicrobial Bacterial Cellulose-Silver Nanoparticles Composite Membranes

Directory of Open Access Journals (Sweden)

Hernane S. Barud

2011-01-01

Full Text Available Antimicrobial bacterial cellulose-silver nanoparticles composite membranes have been obtained by “in situ” preparation of Ag nanoparticles from hydrolytic decomposition of silver nitrate solution using triethanolamine as reducing and complexing agent. The formation of silver nanoparticles was evidenced by the X-ray diffraction, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and absorption in the UV-Visible (350 nm to 600 nm. Thermal and mechanical properties together with swelling behavior for water were considered. TEA concentration was observed to be important in order to obtain only Ag particles and not a mixture of silver oxides. It was also observed to control particle size and amount of silver contents in bacterial cellulose. The composite membranes exhibited strong antimicrobial activity against Gram-negative and Gram-positive bacteria.

Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

Science.gov (United States)

Wen, Li; Lin, Zhonghua; Gu, Pingying; Zhou, Jianzhang; Yao, Bingxing; Chen, Guoliang; Fu, Jinkun

2009-02-01

Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 °C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (gold nanoparticles capped with thiol of 1.9 ± 0.8 nm size were formed by using Bacillus megatherium D01.

Biosynthesis of silver nanoparticles by Aspergillus niger , Fusarium ...

African Journals Online (AJOL)

... scanning electron microscope (SEM). Results indicate the synthesis of silver nanoparticles in the reaction mixture. The synthesis of nanoparticles would be suitable for developing a microbial nanotechnology biosynthesis process for mass scale production. Keywords: Silver nanoparticles, biosynthesis, fungi, Aspergillus.

Biosynthesis of silver nanoparticles using Stevia extracts

International Nuclear Information System (INIS)

Laguta, I.V.; Fesenko, T.V.; Stavinskaya, O.N.; Shpak, L.M.; Dzyuba, O.I.

2015-01-01

Silver nanoparticles are synthesized using Stevia rebaudiana extracts. It is shown that the rate of nanoparticles formation is affected by plant cultivation conditions. It is found that, in the presence of the extract from callus, the formation of nanoparticles occurs faster than in the presence of extracts from plants grown under conditions of ex situ and in vitro. The synthesized silver nanoparticles were studied by UV and IR spectroscopies

Qualitative assessment of silver and gold nanoparticle synthesis in various plants: a photobiological approach

Science.gov (United States)

Rajasekharreddy, Pala; Usha Rani, Pathipati; Sreedhar, Bojja

2010-06-01

The development of rapid and ecofriendly processes for the synthesis of silver (Ag) and gold (Au) nanoparticles is of great importance in the field of nanotechnology. In this study, the extracellular production of Ag and Au nanoparticles was carried out from the leaves of the plants, Tridax procumbens L. (Coat buttons), Jatropa curcas L. (Barbados nut), Calotropis gigantea L. (Calotropis), Solanum melongena L. (Eggplant), Datura metel L. (Datura), Carica papaya L. (Papaya) and Citrus aurantium L. (Bitter orange) by the sunlight exposure method. Qualitative comparisons of the synthesized nanoparticles between the plants were measured. Among these T. procumbens, J. curcas and C. gigantea plants synthesized <20 nm sized and spherical-shaped Ag particles, whereas C. papaya, D. metel and S. melongena produced <20 nm sized monodispersed Au particles. The amount of nanoparticles synthesized and its qualitative characterization was done by UV-vis spectroscopy and transmission electron microscopy (TEM), respectively. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used for structural confirmation. Further analysis carried out by fourier transform infrared spectroscopy (FTIR), provided evidence for the presence of amino groups, which increased the stability of the synthesized nanoparticles.

Qualitative assessment of silver and gold nanoparticle synthesis in various plants: a photobiological approach

International Nuclear Information System (INIS)

Rajasekharreddy, Pala; Usha Rani, Pathipati; Sreedhar, Bojja

2010-01-01

The development of rapid and ecofriendly processes for the synthesis of silver (Ag) and gold (Au) nanoparticles is of great importance in the field of nanotechnology. In this study, the extracellular production of Ag and Au nanoparticles was carried out from the leaves of the plants, Tridax procumbens L. (Coat buttons), Jatropa curcas L. (Barbados nut), Calotropis gigantea L. (Calotropis), Solanum melongena L. (Eggplant), Datura metel L. (Datura), Carica papaya L. (Papaya) and Citrus aurantium L. (Bitter orange) by the sunlight exposure method. Qualitative comparisons of the synthesized nanoparticles between the plants were measured. Among these T. procumbens, J. curcas and C. gigantea plants synthesized <20 nm sized and spherical-shaped Ag particles, whereas C. papaya, D. metel and S. melongena produced <20 nm sized monodispersed Au particles. The amount of nanoparticles synthesized and its qualitative characterization was done by UV-vis spectroscopy and transmission electron microscopy (TEM), respectively. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used for structural confirmation. Further analysis carried out by fourier transform infrared spectroscopy (FTIR), provided evidence for the presence of amino groups, which increased the stability of the synthesized nanoparticles.

The immunomodulatory effects of titanium dioxide and silver nanoparticles.

Science.gov (United States)

Lappas, Courtney M

2015-11-01

Due to their characteristic physical, chemical and optical properties, titanium dioxide and silver nanoparticles are attractive tools for use in a wide range of applications. The use of nanoparticles for biological applications is, however, dependent upon their biocompatibility with living cells. Because of the importance of inflammation as a modulator of human health, the safe and efficacious in vivo use of titanium dioxide and silver nanoparticles is inherently linked to a favorable interaction with immune system cells. However, both titanium dioxide and silver nanoparticles have demonstrated potential to exert immunomodulatory and immunotoxic effects. Titanium dioxide and silver nanoparticles are readily internalized by immune system cells, may accumulate in peripheral lymphoid organs, and can influence multiple manifestations of immune cell activity. Although the factors influencing the biocompatibility of titanium dioxide and silver nanoparticles with immune system cells have not been fully elucidated, nanoparticle core composition, size, concentration and the duration of cell exposure seem to be important. Because titanium dioxide and silver nanoparticles are widely utilized in pharmaceutical, commercial and industrial products, it is vital that their effects on human health and immune system function be more thoroughly evaluated. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Synthesis of Silver Nanoparticles Produced by Chemical Reduction of Silver Salt Solution

International Nuclear Information System (INIS)

Sri Budi Harmani; Dewi Sondari; Agus Haryono

2008-01-01

Described in this research are the synthesis of silver nanoparticle produced by chemical reduction of silver salt (silver nitrate AgNO 3 ) solution. As a reducer, sodium citrate (C 6 H 5 O 7 Na 3 ) was used. Preparation of silver colloid is done by using chemical reduction method. In typical experiment 150 ml of 1.10 -3 M AgNO 3 solution was heated with temperature variation such as 90, 100, 110 degree of Celsius. To this solution 15 ml of 1 % trisodium citrate was added into solution drop by drop during heating. During the process, solution was mixed vigorously. Solution was heated until colour's change is evident (pale yellow solution is formed). Then it was removed from the heating element and stirred until cooled to room temperature. Experimental result showed that diameter of silver nanoparticles in colloid solution is about 28.3 nm (Ag colloid, 90 o C); 19.9 nm (Ag colloid, 100 o C)and 26.4 nm (Ag colloid, 110 o C). Characterization of the silver nanoparticle colloid conducted by using UV-Vis Spectroscopy, Particles Size Analyzer (PSA) and Scanning Electron Microscope (SEM) indicate the produced structures of silver nanoparticles. (author)

Self-assembled silver nanoparticles monolayers on mica-AFM, SEM, and electrokinetic characteristics.

Science.gov (United States)

Oćwieja, Magdalena; Morga, Maria; Adamczyk, Zbigniew

2013-03-01

A monodisperse silver particle suspension was produced by a chemical reduction method in an aqueous medium using sodium citrate. The average particle size determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) was 28.5 nm. The DLS measurements confirmed that the suspension was stable for the ionic strength up to 3 × 10 -2  M NaCl. The electrophoretic mobility measurements revealed that the electrokinetic charge of particles was negative for pH range 3-10, assuming -50  e for pH = 9 and 0.01 M NaCl. Using the suspension, silver particle monolayers on mica modified by poly(allylamine hydrochloride) were produced under diffusion-controlled transport. Monolayer coverage, quantitatively determined by AFM and SEM, was regulated within broad limits by adjusting the nanoparticle deposition time. This allowed one to uniquely express the zeta potential of silver monolayers, determined by the in situ streaming potential measurements, in terms of particle coverage. Such dependencies obtained for various ionic strengths and pH, were successfully interpreted in terms of the 3D electrokinetic model. A universal calibrating graph was produced in this way, enabling one to determine silver monolayer coverage from the measured value of the streaming potential. Our experimental data prove that it is feasible to produce uniform and stable silver particle monolayers of well-controlled coverage and defined electrokinetic properties.

Electrodeposition of silver nanoparticle arrays on transparent conductive oxides

International Nuclear Information System (INIS)

Zhang, Dezhong; Tang, Yang; Jiang, Fuguo; Han, Zhihua; Chen, Jie

2016-01-01

Highlights: • The sliver nanoparticles' size and the distance between nanoparticles are tunable. - Abstract: In this paper, we present a facile method for the preparation of silver nanoparticles on aluminum-doped zinc oxide (AZO) via electrodeposition techniques at room temperature. The morphology and structure of silver nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), respectively. Due to localized surface plasmon resonances, as-prepared silver nanoparticles on AZO glass exhibited different reflectivity in contrast with bare AZO glass. The weighted reflection of AZO substrate increased from 10.2% to 12.8%. The high reflection property of silver nanoparticle arrays on AZO substrate might be applicable for thin film solar cells and other optoelectronics applications.

Electrodeposition of silver nanoparticle arrays on transparent conductive oxides

Energy Technology Data Exchange (ETDEWEB)

Zhang, Dezhong; Tang, Yang, E-mail: tangyang@nicenergy.com; Jiang, Fuguo; Han, Zhihua; Chen, Jie

2016-04-30

Highlights: • The sliver nanoparticles' size and the distance between nanoparticles are tunable. - Abstract: In this paper, we present a facile method for the preparation of silver nanoparticles on aluminum-doped zinc oxide (AZO) via electrodeposition techniques at room temperature. The morphology and structure of silver nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), respectively. Due to localized surface plasmon resonances, as-prepared silver nanoparticles on AZO glass exhibited different reflectivity in contrast with bare AZO glass. The weighted reflection of AZO substrate increased from 10.2% to 12.8%. The high reflection property of silver nanoparticle arrays on AZO substrate might be applicable for thin film solar cells and other optoelectronics applications.

Synthesis, characterization and SERS activity of biosynthesized silver nanoparticles

Science.gov (United States)

Bindhu, M. R.; Sathe, V.; Umadevi, M.

2013-11-01

Silver nanoparticles were rapidly synthesized using Moringa oleifera flower extract as the reducing agent shows surface plasmon resonance peak at 439 nm. The size and shape of the nanoparticles controlled by varying the concentration of M. oleifera flower extract in the reaction medium. The synthesized silver nanoparticles were well-dispersed spherical nanoparticles with the average size of 14 nm. The retinoic acid present in M. oleifera flower extract used as reducing agent and proteins was responsible for capping of the bioreduced silver nanoparticles. The obtained nanoparticle shows size-dependent SERS activity. The SERS spectrum indicates that the pyridine adsorbed on the silver surface in a stand-on orientation via its nitrogen lone pair electrons.

Biosynthesis of silver nanoparticles using leaves of Stevia rebaudiana

International Nuclear Information System (INIS)

Yilmaz, M.; Turkdemir, H.; Kilic, M. Akif; Bayram, E.; Cicek, A.; Mete, A.; Ulug, B.

2011-01-01

Highlights: → Green synthesis of silver nanoparticles using leaves of Stevia Rebaudiana. → Spherical and polydispersed nanoparticles with diameters below 50 nm. → Interplay of nanoparticle formation and aggregation over time. → Capping reagents similar to those in gold synthesis via the same biomass. → Ketones to play active roles in the reduction of silver ions. - Abstract: The synthesis of silver nanoparticles employing a shadow-dried Stevia rebaudiana leaf extract in AgNO 3 solution is reported. Transmission electron microscopy and X-ray diffraction inspections indicate that nanoparticles are spherical and polydispersed with diameters ranging between 2 and 50 nm with a maximum at 15 nm. Ultraviolet-visible spectra recorded against the reaction time confirms the reduction of silver nanoparticles indicating that the formation and the aggregation of nanoparticles take place shortly after the mixing, as they persist concurrently with characteristic times of 48.5 min and 454.5 min, respectively. Aggregation is found to be the dominant mechanism after the first 73 min. Proton nuclear magnetic resonance spectrum of the silver nanoparticles reveals the existence of aliphatic, alcoholic and olefinic CH 2 and CH 3 groups, as well as some aromatic compounds but no sign of aldehydes or carboxylic acids. Infrared absorption of the silver nanoparticles suggests that the capping reagents of silver and gold nanoparticles reduced in plant extracts/broths are of the same chemical composition of different ratios. Ketones are shown to play a somehow active role for the formation of nanoparticles in plant extracts/broths.

Biosynthesis of silver nanoparticles using leaves of Stevia rebaudiana

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, M. [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Bartin University, Bartin (Turkey); Turkdemir, H. [Department of Chemistry, Faculty of Arts and Sciences, Uludag University, 16059 Goeruekle, Bursa (Turkey); Kilic, M. Akif [Department of Biology, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey); Bayram, E. [Department of Chemistry, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey); Cicek, A. [Department of Physics, Faculty of Arts and Sciences, Mehmet Akif Ersoy University, 15100 Burdur (Turkey); Department of Physics, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey); Mete, A. [Department of Chemistry, Faculty of Arts and Sciences, Inonu University, Malatya (Turkey); Ulug, B., E-mail: bulug@akdeniz.edu.tr [Department of Physics, Faculty of Science, Akdeniz University, Campus 07058, Antalya (Turkey)

2011-11-01

Highlights: {yields} Green synthesis of silver nanoparticles using leaves of Stevia Rebaudiana. {yields} Spherical and polydispersed nanoparticles with diameters below 50 nm. {yields} Interplay of nanoparticle formation and aggregation over time. {yields} Capping reagents similar to those in gold synthesis via the same biomass. {yields} Ketones to play active roles in the reduction of silver ions. - Abstract: The synthesis of silver nanoparticles employing a shadow-dried Stevia rebaudiana leaf extract in AgNO{sub 3} solution is reported. Transmission electron microscopy and X-ray diffraction inspections indicate that nanoparticles are spherical and polydispersed with diameters ranging between 2 and 50 nm with a maximum at 15 nm. Ultraviolet-visible spectra recorded against the reaction time confirms the reduction of silver nanoparticles indicating that the formation and the aggregation of nanoparticles take place shortly after the mixing, as they persist concurrently with characteristic times of 48.5 min and 454.5 min, respectively. Aggregation is found to be the dominant mechanism after the first 73 min. Proton nuclear magnetic resonance spectrum of the silver nanoparticles reveals the existence of aliphatic, alcoholic and olefinic CH{sub 2} and CH{sub 3} groups, as well as some aromatic compounds but no sign of aldehydes or carboxylic acids. Infrared absorption of the silver nanoparticles suggests that the capping reagents of silver and gold nanoparticles reduced in plant extracts/broths are of the same chemical composition of different ratios. Ketones are shown to play a somehow active role for the formation of nanoparticles in plant extracts/broths.

Subchronic oral toxicity of silver nanoparticles

Directory of Open Access Journals (Sweden)

Kim Yong

2010-08-01

Full Text Available Abstract Background The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, consumer, medicinal, pesticide, and home products; however, silver nanoparticles remain a controversial area of research with respect to their toxicity in biological and ecological systems. Results This study tested the oral toxicity of silver nanoparticles (56 nm over a period of 13 weeks (90 days in F344 rats following Organization for Economic Cooperation and Development (OECD test guideline 408 and Good Laboratory Practices (GLP. Five-week-old rats, weighing about 99 g for the males and 92 g for the females, were divided into four 4 groups (10 rats in each group: vehicle control, low-dose (30 mg/kg, middle-dose (125 mg/kg, and high-dose (500 mg/kg. After 90 days of exposure, clinical chemistry, hematology, histopathology, and silver distribution were studied. There was a significant decrease (P Conclusions The target organ for the silver nanoparticles was found to be the liver in both the male and female rats. A NOAEL (no observable adverse effect level of 30 mg/kg and LOAEL (lowest observable adverse effect level of 125 mg/kg are suggested from the present study.

In-site synthesis of monodisperse, oleylamine-capped Ag nanoparticles through microemulsion approach

Energy Technology Data Exchange (ETDEWEB)

Chen, Shun; Ju, Yanyun [Wuhan University of Technology, School of Materials Science and Engineering (China); Guo, Yi [Wuhan University of Technology, Center for Materials Research and Analysis (China); Xiong, Chuanxi; Dong, Lijie, E-mail: dong@whut.edu.cn [Wuhan University of Technology, School of Materials Science and Engineering (China)

2017-03-15

Ag NPs were in-site synthesized through microemulsion method by reducing silver acetate with oleylamine-mediated at 70 °C with highly monodisperse and narrow size from 10 to 20 nm. The synthesis of Ag NPs was aided by oleylamine and the role of oleylamine was researched. This in-site synthesis approach to Ag NPs was reproducibility and high yield more than 80% with stable store about 6 months.

Precise micropatterning of silver nanoparticles on plastic substrates

International Nuclear Information System (INIS)

Ammosova, Lena; Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.

2017-01-01

Highlights: • Silver ink has been deposited on plastic substrate and silver nanoparticles have been produced. • 3D control allows both ink superimposing and deposition on complicated surfaces. • Polyol method ensures the formation of metallic mircopatterns with high uniformity. • Substrate wettability, ink volume, and sintering temperature influences deposited patterns. - Abstract: Conventional fabrication methods to obtain metal patterns on polymer substrates are restricted by high operating temperature and complex preparation steps. The present study demonstrates a simple yet versatile method for preparation of silver nanoparticle micropatterns on polymer substrates with various surface geometry. With the microworking robot technique, we were able not only to directly structure the surface, but also precisely deposit silver nanoparticle ink on the desired surface location with the minimum usage of ink material. The prepared silver nanoparticle ink, containing silver cations and polyethylene glycol (PEG) as a reducing agent, yields silver nanoparticle micropatterns on plastic substrates at low sintering temperature without any contamination. The influence of the ink behaviour was studied, such as substrate wettability, ink volume, and sintering temperature. The ultraviolet visible (UV–vis), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements revealed the formation of micropatterns with uniformly distributed silver nanoparticles. The prepared patterns are expected to have a broad range of applications in optics, medicine, and sensor devices owing to the unique properties of silver. Furthermore, the deposition of a chemical compound, which is different from the substrate material, not only adds a fourth dimension to the prestructured three-dimensional (3D) surfaces, but also opens new application areas to the conventional surface structures.

Precise micropatterning of silver nanoparticles on plastic substrates

Energy Technology Data Exchange (ETDEWEB)

Ammosova, Lena; Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A., E-mail: tapani.pakkanen@uef.fi

2017-04-15

Highlights: • Silver ink has been deposited on plastic substrate and silver nanoparticles have been produced. • 3D control allows both ink superimposing and deposition on complicated surfaces. • Polyol method ensures the formation of metallic mircopatterns with high uniformity. • Substrate wettability, ink volume, and sintering temperature influences deposited patterns. - Abstract: Conventional fabrication methods to obtain metal patterns on polymer substrates are restricted by high operating temperature and complex preparation steps. The present study demonstrates a simple yet versatile method for preparation of silver nanoparticle micropatterns on polymer substrates with various surface geometry. With the microworking robot technique, we were able not only to directly structure the surface, but also precisely deposit silver nanoparticle ink on the desired surface location with the minimum usage of ink material. The prepared silver nanoparticle ink, containing silver cations and polyethylene glycol (PEG) as a reducing agent, yields silver nanoparticle micropatterns on plastic substrates at low sintering temperature without any contamination. The influence of the ink behaviour was studied, such as substrate wettability, ink volume, and sintering temperature. The ultraviolet visible (UV–vis), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements revealed the formation of micropatterns with uniformly distributed silver nanoparticles. The prepared patterns are expected to have a broad range of applications in optics, medicine, and sensor devices owing to the unique properties of silver. Furthermore, the deposition of a chemical compound, which is different from the substrate material, not only adds a fourth dimension to the prestructured three-dimensional (3D) surfaces, but also opens new application areas to the conventional surface structures.

Synthesis of silver nanoparticles using medicinal Zizyphus xylopyrus bark extract

Science.gov (United States)

Sumi Maria, Babu; Devadiga, Aishwarya; Shetty Kodialbail, Vidya; Saidutta, M. B.

2015-08-01

In the present paper, biosynthesis of silver nanoparticles using Zizyphus xylopyrus bark extract is reported. Z. xylopyrus bark extract is efficiently used for the biosynthesis of silver nanoparticles. UV-Visible spectroscopy showed surface plasmon resonance peaks in the range 413-420 nm confirming the formation of silver nanoparticles. Different factors affecting the synthesis of silver nanoparticles like methodology for the preparation of extract, concentration of silver nitrate solution used for biosynthesis and initial pH of the reaction mixture were studied. The extract prepared with 10 mM AgNO3 solution by reflux extraction method at optimum initial pH of 11, resulted in higher conversion of silver ions to silver nanoparticles as compared with those prepared by open heating or ultrasonication. SEM analysis showed that the biosynthesized nanoparticles are spherical in nature and ranged from 60 to 70 nm in size. EDX suggested that the silver nanoparticles must be capped by the organic components present in the plant extract. This simple process for the biosynthesis of silver nanoparticles using aqueous extract of Z. xylopyrus is a green technology without the usage of hazardous and toxic solvents and chemicals and hence is environment friendly. The process has several advantages with reference to cost, compatibility for its application in medical and drug delivery, as well as for large-scale commercial production.

Silver Nanoparticles and Graphitic Carbon Through Thermal Decomposition of a Silver/Acetylenedicarboxylic Salt

Directory of Open Access Journals (Sweden)

Komninou Philomela

2009-01-01

Full Text Available Abstract Spherically shaped silver nanoparticles embedded in a carbon matrix were synthesized by thermal decomposition of a Ag(I/acetylenedicarboxylic acid salt. The silver nanoparticles, which are formed either by pyrolysis at 300 °C in an autoclave or thermolysis in xylene suspension at reflux temperature, are acting catalytically for the formation of graphite layers. Both reactions proceed through in situ reduction of the silver cations and polymerization of the central acetylene triple bonds and the exact temperature of the reaction can be monitored through DTA analysis. Interestingly, the thermal decomposition of this silver salt in xylene partly leads to a minor fraction of quasicrystalline silver, as established by HR-TEM analysis. The graphitic layers covering the silver nanoparticles are clearly seen in HR-TEM images and, furthermore, established by the presence of sp2carbon at the Raman spectrum of both samples.

Cytotoxicity and antimicrobial activities of green synthesized silver nanoparticles.

Science.gov (United States)

Lokina, S; Stephen, A; Kaviyarasan, V; Arulvasu, C; Narayanan, V

2014-04-09

Bio-inspired silver nanoparticles are synthesized using Malus domestica (apple) extract. Polyphenols present in the apple extract act as a reducing and capping agent to produce the silver nanoparticles. UV-Visible analysis shows the surface plasmon resonance (SPR) absorption at 420 nm. The FTIR analysis was used to identify the functional groups responsible for the bio-reduction of silver ion. The XRD and HRTEM images confirm the formation of silver nanoparticles. The minimal inhibitory concentration (MIC) of silver nanoparticles was recorded against most of the bacteria and fungus. Further, MCF-7 human breast adenocarcinoma cancer cell line was employed to observe the efficacy of cancer cell killing. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp.

Science.gov (United States)

Thomas, Roshmi; Janardhanan, Anju; Varghese, Rintu T; Soniya, E V; Mathew, Jyothis; Radhakrishnan, E K

2014-01-01

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp.

Directory of Open Access Journals (Sweden)

Roshmi Thomas

2014-12-01

Full Text Available Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM and scanning electron microscope (SEM. The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

Biosynthesis of silver nanoparticles and its antibacterial activity ...

African Journals Online (AJOL)

In the present research work, biosynthesis of silver nanoparticles and its activity on bacterial pathogens were investigated. Silver nanoparticles were rapidly synthesized using Urospora sp. and the formation of nanoparticles was observed within 30 min. The results recorded from UV–vis spectrum, Fourier Transform Infrared ...

Cytotoxicity and genotoxicity of biogenic silver nanoparticles

International Nuclear Information System (INIS)

Lima, R; Feitosa, L O; Ballottin, D; Tasic, L; Durán, N; Marcato, P D

2013-01-01

Biogenic silver nanoparticles with 40.3 ± 3.5 nm size and negative surface charge (− 40 mV) were prepared with Fusarium oxysporum. The cytotoxicity of 3T3 cell and human lymphocyte were studied by a TaliTM image-based cytometer and the genotoxicity through Allium cepa and comet assay. The results of BioAg-w (washed) and BioAg-nw (unwashed) biogenic silver nanoparticles showed cytotoxicity exceeding 50 μg/mL with no significant differences of response in 5 and 10 μg/mL regarding viability. Results of genotoxicity at concentrations 5.0 and 10.0 ug/mL show some response, but at concentrations 0.5 and 1.0 μg/mL the washed and unwashed silver nanoparticles did not present any effect. This in an important result since in tests with different bacteria species and strains, including resistant, MIC (minimal inhibitory concentration) had good answers at concentrations less than 1.9 μg/mL. This work concludes that biogenic silver nanoparticles may be a promising option for antimicrobial use in the range where no cyto or genotoxic effect were observed. Furthermore, human cells were found to have a greater resistance to the toxic effects of silver nanoparticles in comparison with other cells.

Synthesis and antimicrobial effects of silver nanoparticles

Directory of Open Access Journals (Sweden)

S kheybari

2010-09-01

Full Text Available "n  "n "nBackground and the purpose of the study:The most prominent nanoparticles for medical uses are nanosilver particles which are famous for their high anti-microbial activity. Silver ion has been known as a metal ion that exhibit anti-mold, anti-microbial and anti-algal properties for a long time. In particular, it is widely used as silver nitrate aqueous solution which has disinfecting and sterilizing actions. The purpose of this study was to evaluate the antimicrobial activity as well as physical properties of the silver nanoparticles prepared by chemical reduction method. "nMethods:Silver nanoparticles (NPs were prepared by reduction of silver nitrate in the presence of a reducing agent and also poly [N-vinylpyrolidone] (PVP as a stabilizer. Two kinds of NPs were synthesized by ethylene glycol (EG and glucose as reducing agent. The nanostructure and particle size of silver NPs were confirmed by scanning electron microscopy (SEM and laser particle analyzer (LPA. The formations of the silver NPs were monitored using ultraviolet-visible spectroscopy. The anti-bacterial activity of silver NPs were assessed by determination of their minimum inhibitory concentrations (MIC against the Gram positive (Staphylococcus aureus and Staphylococcus epidermidis as well as Gram-negative (Escherichia coli and Pseudomonas aeruginosa bacteria. "nResults and Conclusion:The silver nanoparticles were spherical with particle size between 10 to 250 nm. Analysis of the theoretical (Mie light scattering theory and experimental results showed that the silver NPs in colloidal solution had a diameter of approximately 50 nm. "nBoth colloidal silver NPs showed high anti-bacterial activity against Gram positive and Gram negative bacteria. Glucose nanosilver colloids showed a shorter killing time against most of the tested bacteria which could be due to their nanostructures and uniform size distribution patterns.

Synthesis and characterization of silver nanoparticles in AOT microemulsion system

International Nuclear Information System (INIS)

Zhang Wanzhong; Qiao Xueliang; Chen Jianguo

2006-01-01

Colloidal silver nanoparticles have been synthesized in water-in-oil microemulsion using silver nitrate solubilized in the water core of one microemulsion as source of silver ions, hydrazine hydrate solubilized in the water core of another microemulsion as reducing agent, dodecane as the oil phase, sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as the surfactant. The UV-vis absorption spectra and transmission electron microscopy (TEM) have been used to trace the growth process and elucidate the structure of the silver nanoparticles. UV-vis spectra show that the Ag 4 + intermediates formed at early stages of the reaction and then the clusters grow or aggregate to larger nanoparticles. TEM micrographs confirm that the silver nanoparticles are all spherical. The resulting particles have a very narrow size distribution. Meanwhile, the diameter size of the particles is so small that the smallest mean diameter is only 1.6nm. IR results show that the surfactant molecules are strongly adsorbed on the surface of silver particles through a coordination bond between the silver atom and the sulfonic group of AOT molecules, which endows the particles with a good stability in oil solvents. As dodecane is used as oil solvent to prepare silver nanoparticles, the formed nano-silver sol is almost nontoxic. As a result, the silver nanoparticles need not be separated from the reaction solution and the silver sol may be directly used in antibacterial fields

Studying the morphological features of plasma treated silver and PEGylated silver nanoparticles: antibacterial activity

Science.gov (United States)

Waseem, M.; Awan, T.; Yasin, H. M.; Rehman, N. U.

2018-03-01

A strategy to treat the silver and PEGylated silver nanoparticles with plasma was being purposed. Oil in water (o/w) microemulsion method was used for the synthesis of Ag nanoparticles (AgNPs). Polyethylene glycol (PEG) having molecular weight 600 was used to coat the surface of AgNPs. Optical emission spectroscopy (OES) was used to characterize the plasma and it is noted that plasma treatment is useful to modify the structural characteristic of silver nanoparticles. The nanoparticles were treated with helium-oxygen mixture plasma, generated in plasma needle at atmospheric pressure. Both AgNPs and PEGylated AgNPs before and after plasma treatment were characterized by x-rays diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The crystallite size of silver nanoparticles after the treatment of plasma decreases from 71 nm to 27 nm. The SEM micrographs show that the size of Ag nanoparticles was nearly 118 nm whereas the thickness of the silver needle was around 135 nm. All the characteristics IR bands associated to the silver nanoparticles were detected. The FTIR spectrum also support the accumulation of OH radicals in the plasma treated samples. The samples before and after plasma treatment were screened against Gram positive (Bacillus Subtilis and Staphylococcus Aureus) and Gram negative (Escherichia Coli and Pseudomonas Aeruginosa) bacteria. The promising response was detected when plasma treated PEGylated AgNPs was tested against bacterial strains.

Toxicity of silver nanoparticles against bacteria, yeast, and algae

Energy Technology Data Exchange (ETDEWEB)

Dorobantu, Loredana S., E-mail: loredana@ualberta.ca; Fallone, Clara [University of Alberta, Department of Chemical and Materials Engineering (Canada); Noble, Adam J. [Trent University, Department of Biology (Canada); Veinot, Jonathan; Ma, Guibin [University of Alberta, Department of Chemistry (Canada); Goss, Greg G. [University of Alberta, Department of Biological Sciences (Canada); Burrell, Robert E. [University of Alberta, Department of Biomedical Engineering (Canada)

2015-04-15

The toxicity mechanism employed by silver nanoparticles against microorganisms has captivated scientists for nearly a decade and remains a debatable issue. The question most frequently asked is whether silver nanoparticles exert specific effects on microorganisms beyond the well-documented antimicrobial activity of Ag{sup +}. Here, we study the effects of citrate- (d = 17.5 ± 9.4 nm) and 11-mercaptoundecanoic acid (d = 38.8 ± 3.6 nm)-capped silver nanoparticles on microorganisms belonging to various genera. The antimicrobial effect of Ag{sup +} was distinguished from that of nanosilver by monitoring microbial growth in the presence and absence of nanoparticles and by careful comparison of the responses of equimolar silver nitrate solution. The results show that when using equimolar silver solutions, silver nitrate has higher toxic potential on all microorganisms than both nanoparticles tested. Furthermore, some microorganisms are more susceptible to silver than others and the choice of capping agent is relevant in the toxicity. Atomic force microscopy disclosed that AgNO{sub 3} had a destructive effect on algae. The antimicrobial activity of nanosilver could be exploited to prevent microbial colonization of medical devices and to determine the fate of nanoparticles in the environment.

Toxicity of silver nanoparticles against bacteria, yeast, and algae

International Nuclear Information System (INIS)

Dorobantu, Loredana S.; Fallone, Clara; Noble, Adam J.; Veinot, Jonathan; Ma, Guibin; Goss, Greg G.; Burrell, Robert E.

2015-01-01

The toxicity mechanism employed by silver nanoparticles against microorganisms has captivated scientists for nearly a decade and remains a debatable issue. The question most frequently asked is whether silver nanoparticles exert specific effects on microorganisms beyond the well-documented antimicrobial activity of Ag + . Here, we study the effects of citrate- (d = 17.5 ± 9.4 nm) and 11-mercaptoundecanoic acid (d = 38.8 ± 3.6 nm)-capped silver nanoparticles on microorganisms belonging to various genera. The antimicrobial effect of Ag + was distinguished from that of nanosilver by monitoring microbial growth in the presence and absence of nanoparticles and by careful comparison of the responses of equimolar silver nitrate solution. The results show that when using equimolar silver solutions, silver nitrate has higher toxic potential on all microorganisms than both nanoparticles tested. Furthermore, some microorganisms are more susceptible to silver than others and the choice of capping agent is relevant in the toxicity. Atomic force microscopy disclosed that AgNO 3 had a destructive effect on algae. The antimicrobial activity of nanosilver could be exploited to prevent microbial colonization of medical devices and to determine the fate of nanoparticles in the environment

Synthesis and optical properties of silver nanoparticles

Science.gov (United States)

Singh, Jaiveer; Kaurav, Netram; Choudhary, K. K.; Okram, Gunadhor S.

2015-07-01

The preparation of stable, uniform silver nanoparticles by reduction of silver acetate by ethylene glycol (EG) is reported in the present paper. It is a simple process of recent interest for obtaining silver nanoparticles. The samples were characterized by X-Ray diffraction (XRD), which reveals an average particle size (D) of 38 nm. The UV/Vis spectra show that an absorption peak, occurring due to surface plasmon resonance (SPR), exists at 319 nm.

Gold core@silver semishell Janus nanoparticles prepared by interfacial etching

Science.gov (United States)

Chen, Limei; Deming, Christopher P.; Peng, Yi; Hu, Peiguang; Stofan, Jake; Chen, Shaowei

2016-07-01

Gold core@silver semishell Janus nanoparticles were prepared by chemical etching of Au@Ag core-shell nanoparticles at the air/water interface. Au@Ag core-shell nanoparticles were synthesized by chemical deposition of a silver shell onto gold seed colloids followed by the self-assembly of 1-dodecanethiol onto the nanoparticle surface. The nanoparticles then formed a monolayer on the water surface of a Langmuir-Blodgett trough, and part of the silver shell was selectively etched away by the mixture of hydrogen peroxide and ammonia in the water subphase, where the etching was limited to the side of the nanoparticles that was in direct contact with water. The resulting Janus nanoparticles exhibited an asymmetrical distribution of silver on the surface of the gold cores, as manifested in transmission electron microscopy, UV-vis absorption, and X-ray photoelectron spectroscopy measurements. Interestingly, the Au@Ag semishell Janus nanoparticles exhibited enhanced electrocatalytic activity in oxygen reduction reactions, as compared to their Au@Ag and Ag@Au core-shell counterparts, likely due to a synergistic effect between the gold cores and silver semishells that optimized oxygen binding to the nanoparticle surface.Gold core@silver semishell Janus nanoparticles were prepared by chemical etching of Au@Ag core-shell nanoparticles at the air/water interface. Au@Ag core-shell nanoparticles were synthesized by chemical deposition of a silver shell onto gold seed colloids followed by the self-assembly of 1-dodecanethiol onto the nanoparticle surface. The nanoparticles then formed a monolayer on the water surface of a Langmuir-Blodgett trough, and part of the silver shell was selectively etched away by the mixture of hydrogen peroxide and ammonia in the water subphase, where the etching was limited to the side of the nanoparticles that was in direct contact with water. The resulting Janus nanoparticles exhibited an asymmetrical distribution of silver on the surface of the gold

Distribution of silver in rats following 28 days of repeated oral exposure to silver nanoparticles or silver acetate

DEFF Research Database (Denmark)

Löschner, Katrin; Hadrup, Niels; Qvortrup, Klaus

2011-01-01

Background: The study investigated the distribution of silver after 28 days repeated oral administration of silver nanoparticles (AgNPs) and silver acetate (AgAc) to rats. Oral administration is a relevant route of exposure because of the use of silver nanoparticles in products related to food...... and food contact materials. Results: AgNPs were synthesized with a size distribution of 14 ± 4 nm in diameter (90% of the nanoparticle volume) and stabilized in aqueous suspension by the polymer polyvinylpyrrolidone (PVP). The AgNPs remained stable throughout the duration of the 28-day oral toxicity study...... in rats. The organ distribution pattern of silver following administration of AgNPs and AgAc was similar. However the absolute silver concentrations in tissues were lower following oral exposure to AgNPs. This was in agreement with an indication of a higher fecal excretion following administration of Ag...

Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species

Science.gov (United States)

Pourshahid, Seyedmohammad; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

2016-01-01

Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity. PMID:27652264

Synthesis and characterization of silver nanoparticles: effect on phytopathogen Colletotrichum gloesporioides

Science.gov (United States)

Aguilar-Méndez, Miguel A.; San Martín-Martínez, Eduardo; Ortega-Arroyo, Lesli; Cobián-Portillo, Georgina; Sánchez-Espíndola, Esther

2011-06-01

Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin as capping agent. The obtained nanoparticles were characterized by means of UV-Vis spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV-Vis spectra indicated the formation of silver nanoparticles preferably spherical and of relatively small size (silver nanoparticles. By means of FTIR spectroscopy it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration. The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner.

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...

Green synthesis of silver nanoparticles and their characterization by XRD

Science.gov (United States)

Mehta, B. K.; Chhajlani, Meenal; Shrivastava, B. D.

2017-05-01

A cost effective and environment friendly technique for green synthesis of silver nanoparticles has been reported. Silver nanoparticles have been synthesized using ethanol extract of fruits of Santalum album (Family Santalaceae), commonly known as East Indian sandalwood. Fruits of S.album were collected and crushed. Ethanol was added to the crushed fruits and mixture was exposed to microwave for few minutes. Extract was concentrated by Buchi rotavaporator. To this extract, 1mM aqueous solution of silver nitrate (AgNO3) was added. After about 24 hr incubation Ag+ ions in AgNO3 solution were reduced to Ag atoms by the extract. Silver nanoparticles were obtained in powder form. X-ray diffraction (XRD) pattern of the prepared sample of silver nanoparticles was recorded The diffractogram has been compared with the standard powder diffraction card of JCPDS silver file. Four peaks have been identified corresponding to (hkl) values of silver. The XRD study confirms that the resultant particles are silver nanoparticles having FCC structure. The average crystalline size D, the value of the interplanar spacing between the atoms, d, lattice constant and cell volume have been estimated. Thus, silver nanoparticles with well-defined dimensions could be synthesized by reduction of metal ions due to fruit extract of S.album.

Green Synthesis of Silver Nanoparticles by using Eucalyptus Globulus Leaf Extract

Science.gov (United States)

Balamurugan, Madheswaran; Saravanan, Shanmugam

2017-12-01

A single step eco-friendly, energy efficient and economically scalable green method was employed to synthesize silver nanoparticles. In this work, the synthesis of silver nanoparticles using Eucalyptus globulus leaf extract as reducing and capping agent along with water as solvent at normal room temperature is described. Silver nanoparticles were prepared from aqueous silver nitrate solution by adding the leaf extract. The prepared nanoparticles were characterized by using UV-visible Spectrophotometer, X-ray diffractometer, High Resolution Transmission Electron Microscope (HR-TEM) and Fourier Transform Infrared Spectroscope (FTIS). X-ray diffraction studies brought to light the crystalline nature and the face centered cubic structure of the silver nanoparticles. Using HR-TEM. the nano sizes and morphology of the particles were studied. The mean sizes of the prepared silver nanoparticles ranged from 30 to 36 nm. The density of the particles was tuned by varying the molar ratio of silver nitrate. FTIS studies showed the functional group of organic molecules which were located on the surface of the silver nanoparticles. Originating from the leaf extracts, these organic molecules reduced and capped the particles.

Green synthesis of silver nanoparticles using biopolymers, carboxymethylated-curdlan and fucoidan

International Nuclear Information System (INIS)

Leung, Thomas Chun-Yiu; Wong, Chung Kai; Xie Yong

2010-01-01

There is a growing need in developing a reliable and eco-friendly methodology for the synthesis of metallic nanoparticles, which may be applied for many nanotechnological applications. Natural compounds such as biopolymers are one of the resources which could be used for this purpose. The present study involves the development of a simple, ecological and user-friendly method in synthesizing silver nanoparticles by using carboxymethylated-curdlan or fucoidan as reducing and stabilizing agents. Reduction of silver ions by these biopolymers occurred when heating at 100 deg. C, led to the formation of silver nanoparticles in the range of 40-80 nm in dimensions. The silver nanoparticles were formed readily within 10-15 min. Morphological observation and characterization of the silver nanoparticles were performed by using dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and UV-vis absorption spectrophotometer. The size of silver nanoparticles can be controlled by using different concentrations of carboxymethylated-curdlan, fucoidan or silver nitrate. This way of silver nanoparticles preparation is easy, fast, user-friendly and suitable for large-scale production.

Rapid synthesis of silver nanoparticles from Polylthia longifolia leaves

Directory of Open Access Journals (Sweden)

Tollamadugu Nagavenkata

2012-10-01

Full Text Available Objective: Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are quite often toxic and flammable. In this research article we present a simple and eco-friendly biosynthesis of silver nanoparticles using P. longifolia leaf extract as reducing agent. Methods: Characterization using UV-Vis spectrophotometry, Transmission Electron Microscopy (TEM was performed. Results: TEM showed the formation of silver nanoparticles with an average size of 57 nm. Conclusions: P. longifolia demonstrated strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0. Biological methods are a good competent for the chemical procedures, which are enviro- friendly and convenient.

Non-hazardous anticancerous and antibacterial colloidal 'green' silver nanoparticles.

Science.gov (United States)

Barua, Shaswat; Konwarh, Rocktotpal; Bhattacharya, Satya Sundar; Das, Pallabi; Devi, K Sanjana P; Maiti, Tapas K; Mandal, Manabendra; Karak, Niranjan

2013-05-01

Poly(ethylene glycol) stabilized colloidal silver nanoparticles were prepared using the reductive potency of the aqueous extract of Thuja occidentalis leaves under ambient conditions. The nanoparticles were well dispersed within a narrow size spectrum (7-14 nm) and displayed characteristic surface plasmon resonance peak at around 420 nm and Bragg's reflection planes of fcc structure. MTT assay revealed the dose-dependent cytocompatibility and toxicity of the nanoparticles with the L929 normal cell line. On the other hand, the antiproliferative action of the nanoparticles was evaluated on HeLa cell (cancerous cells) line. Fluorescence and phase contrast microscopic imaging indicated the appearance of multinucleate stages with aggregation and nuclear membrane disruption of the HeLa cells post treatment with the nanoparticles. The interaction at the prokaryotic level was also assessed via differential antibacterial efficacy against Staphylococcus aureus (MTCC 3160) and Escherichia coli (MTCC 40). Under these perspectives, it is also necessary to observe the environmental impact of the prepared silver nanoparticles. Hence, the dose dependent toxicity of silver nanoparticles was evaluated upon the earthworm species Eisenia fetida. Neither the survival nor the reproduction was affected by the addition of silver nanoparticles up to 1000 ppm. Thus these 'green' silver nanoparticles have promising potential as future materials. Copyright © 2012 Elsevier B.V. All rights reserved.

Green synthesis of silver nanoparticles and its application for mosquito control

Directory of Open Access Journals (Sweden)

Naba Kumar Mondal

2014-02-01

Full Text Available Objective: To synthesize and characterize silver nanoparticles from aqueous root extract of Parthenium hysterophorus (P. hysterophorus and also to evaluate the potentiality of synthesized silver nanoparticles as larvacidal agent against Culex quinquefasciatus (Cx. quinquefasciatus. Methods: The silver nano particles were generated using root extract of P. hysterophorus. The characterization of synthesized nanoparticles was done by visual color change, UV-Vis spectrum, scanning electron micrograph, fluorescent microscope and Fourier transform infrared spectroscopy. Results: It was found that aqueous silver ions can be reduced by aqueous root extract of P. hysterophorus to generate extremely stable silver nanoparticles in aqueous medium. Larvae were exposed to varying concentrations of plant extracts, aqueous silver nitrate solution and synthesized silver nanoparticles for 0, 24 and 48 h separately. Aqueous root extract showed moderate larvicidal effects; however, the maximum efficacy (60.18% was observed with the synthesized silver nanoparticles against the larvae of Cx. quinquefasciatus. Conclusions: These results suggest that the green synthesis of silver nanoparticles have the potential to be used as an ideal eco-friently approach for the control of the Cx. quinquefasciatus. This is the first report on the mosquito larvicidal activity of the nano particle synthesized by P. hysterophorus.

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

International Nuclear Information System (INIS)

Agasti, Nityananda; Singh, Vinay K.; Kaushik, N.K.

2015-01-01

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 3 with NaBH 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

In situ reduction of antibacterial silver ions to metallic silver nanoparticles on bioactive glasses functionalized with polyphenols

Energy Technology Data Exchange (ETDEWEB)

Ferraris, S., E-mail: sara.ferraris@polito.it [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy); Miola, M. [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy); Department of Health Sciences, Università del Piemonte Orientale UPO, Via Solaroli 17, 28100, Novara (Italy); Cochis, A.; Azzimonti, B.; Rimondini, L. [Department of Health Sciences, Università del Piemonte Orientale UPO, Via Solaroli 17, 28100, Novara (Italy); Prenesti, E. [Department of Chemistry, Università degli Studi di Torino, Via Pietro Giuria 7, Torino, 10125 (Italy); Vernè, E. [Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129, Torino (Italy)

2017-02-28

Highlights: • Gallic acid and natural polyphenols were grafted onto bioactive glasses. • Grafting ability was dependent on glass reactivity. • In situ reduction of silver nanoparticles was performed onto functionalized glasses. • Bioactive glasses decorated with silver nanoparticles showed antibacterial activity. - Abstract: The realization of surfaces with antibacterial properties due to silver nanoparticles loaded through a green approach is a promising research challenge of the biomaterial field. In this research work, two bioactive glasses have been doubly surface functionalized with polyphenols (gallic acid or natural polyphenols extracted from red grape skins and green tea leaves) and silver nanoparticles deposited by in situ reduction from a silver nitrate aqueous solution. The presence of biomolecules – showing reducing ability to directly obtain in situ metallic silver – and silver nanoparticles was investigated by means of UV–vis spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM). The antibacterial activity of the modified surfaces was tested against a multidrug resistant Staphylococcus aureus bacterial strain.

Growth and galvanic replacement of silver nanocubes in organic media

OpenAIRE

Polavarapu, Lakshminarayana; Liz-Marzan, Luis M.

2013-01-01

Although metal nanoparticles with various shapes can be prepared in polar organic solvents, little has been advanced toward the shape-controlled synthesis in non-polar solvents. We report a simple method for the synthesis of nearly monodisperse single crystalline silver nanocubes in a non-polar solvent (1,2-dichlorobenzene) by using oleylamine as both a reducing and capping agent. Mechanistic studies based on the time evolution of Ag nanoparticles revealed that multiply twinned nanocrystals f...

Biogenic synthesis of silver nanoparticles by leaf extract of Cassia angustifolia

Science.gov (United States)

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

2012-12-01

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

Biogenic synthesis of silver nanoparticles by leaf extract of Cassia angustifolia

International Nuclear Information System (INIS)

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

2012-01-01

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

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.

Synthesis of Silver nanoparticles (AgNPs) with Antibacterial Activity

Science.gov (United States)

Campillo Gloria, E.; Ederley, Vélez; Gladis, Morales; César, Hincapié; Jaime, Osorio; Oscar, Arnache; Uribe José, Ignacio; Franklin, Jaramillo

2017-06-01

The synthesis of nanomaterials is currently one of the most active in nanoscience branches; especially those help improve the human quality life. Silver nanoparticles (AgNPs) are an example of this as it is known to have inhibitory and bactericidal effects. In this work, we report the synthesis of silver nanoparticles by chemical reduction method of silver nitrate (AgNO3) from aqueous solution, using a mix of polivinyl pyrrolidone (PVP) - Aloe Vera as reducing agent and for stabilization and control of particle size. Silver nanoparticles obtained were characterized by Scanning Electron Microscopy (SEM), UV-visible spectroscopy and measurements using Zetasizer Nano ZS were applied to size estimation. The existence of surface plasmon resonance peak at λmax ~ 420 nm is evidence of silver nanoparticles formation. It was possible to standardize an appropriate protocol for the evaluation of bactericidal activity of the nanoparticles, for mesophilic microorganisms. Bactericidal activity above 90% against these kinds of bacteria was demonstrated.

Synthesis of Silver nanoparticles (AgNPs) with Antibacterial Activity

International Nuclear Information System (INIS)

Gloria, E. Campillo; Ederley, Vélez; César, Hincapié; Gladis, Morales; Jaime, Osorio; Oscar, Arnache; José, Ignacio Uribe; Franklin, Jaramillo

2017-01-01

The synthesis of nanomaterials is currently one of the most active in nanoscience branches; especially those help improve the human quality life. Silver nanoparticles (AgNPs) are an example of this as it is known to have inhibitory and bactericidal effects. In this work, we report the synthesis of silver nanoparticles by chemical reduction method of silver nitrate (AgNO 3 ) from aqueous solution, using a mix of polivinyl pyrrolidone (PVP) – Aloe Vera as reducing agent and for stabilization and control of particle size. Silver nanoparticles obtained were characterized by Scanning Electron Microscopy (SEM), UV–visible spectroscopy and measurements using Zetasizer Nano ZS were applied to size estimation. The existence of surface plasmon resonance peak at λ max ∼ 420 nm is evidence of silver nanoparticles formation. It was possible to standardize an appropriate protocol for the evaluation of bactericidal activity of the nanoparticles, for mesophilic microorganisms. Bactericidal activity above 90% against these kinds of bacteria was demonstrated. (paper)

Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

Energy Technology Data Exchange (ETDEWEB)

Grass, Michael Edward [Univ. of California, Berkeley, CA (United States)

2008-09-01

Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H₂ and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.

Silver nanoparticle aggregation not triggered by an ionic strength mechanism

International Nuclear Information System (INIS)

Botasini, Santiago; Méndez, Eduardo

2013-01-01

The synthesis of stable colloidal solutions of silver nanoparticles is a major goal in the industry to control their fate in aqueous solutions. The present work studies 10–20-nm silver nanoparticle aggregation triggered by the presence of chloride ions. The aggregation process was followed by UV–Vis–NIR spectroscopy and transmission electron microscopy. We found that the mechanism involved differs from the classic explanation of nanoparticle aggregation triggered by an increase in the ionic strength. Moreover, our results give evidence that even when nanoparticles are resistant to an increment of the total amount of ions, the formation of insoluble salts in the vicinity of the nanoparticle is enough to induce the aggregation. The presence of silver chloride around the silver nanoparticles was documented by an X-ray diffraction pattern and electrochemical methods because chloride anions are ubiquitous in real media; this alternative process jeopardized the development of many applications with silver nanoparticles that depend on the use of stable colloids.

Silver nanoparticle aggregation not triggered by an ionic strength mechanism

Energy Technology Data Exchange (ETDEWEB)

Botasini, Santiago; Mendez, Eduardo, E-mail: emendez@fcien.edu.uy [Instituto de Quimica Biologica, Universidad de la Republica, Laboratorio de Biomateriales (Uruguay)

2013-04-15

The synthesis of stable colloidal solutions of silver nanoparticles is a major goal in the industry to control their fate in aqueous solutions. The present work studies 10-20-nm silver nanoparticle aggregation triggered by the presence of chloride ions. The aggregation process was followed by UV-Vis-NIR spectroscopy and transmission electron microscopy. We found that the mechanism involved differs from the classic explanation of nanoparticle aggregation triggered by an increase in the ionic strength. Moreover, our results give evidence that even when nanoparticles are resistant to an increment of the total amount of ions, the formation of insoluble salts in the vicinity of the nanoparticle is enough to induce the aggregation. The presence of silver chloride around the silver nanoparticles was documented by an X-ray diffraction pattern and electrochemical methods because chloride anions are ubiquitous in real media; this alternative process jeopardized the development of many applications with silver nanoparticles that depend on the use of stable colloids.

Hydrothermal synthesis of hydroxyapatite nanoparticles decorated with silver nanoparticles for application in biomaterials

International Nuclear Information System (INIS)

Assis, Jordanna Fernandes; Arantes, Tatiane Moraes; Cristovan, F.H.; Tada, Dayane Batista

2016-01-01

Full text: The hydroxyapatite nanoparticles (HA) have research attention because are material that exhibit biocompatibility with bone mineral phase of human body is great interest in the scientific community. Synthetic hydroxyapatite nanoparticles have excellent biocompatibility and bioactivity, due biocompatibility and osteo inducibility [1-3]. The hydroxyapatite nanoparticles were synthesized by hydrothermal processing and were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). The XRD and Raman spectra showed crystalline hydroxyapatite colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated hydroxyapatite surface. TEM images showed HA nanoparticles presented a well defined nanorod shapes and narrow size distributions with dimensions (width and length) around of 5 nm and 50 nm decorated with silver nanoparticles of spherical shape about 20 nm in diameter The results showed that crystalline hydroxyapatite colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. These nanoparticles The cell viability of the HA and HA/Ag was analyzed by reduction of the tetrazolium salt (MTT test). Embryonic mouse fibroblast cells were grown in the presence of nanoparticles for a total period of 96 hours. Analyses were made in 24h, 48h, 72h and 96h. The suspensions at the end of each period were analyzed in spectrophotometer. The 24h experiments were the most conclusive, with the silver presence in the HA, there is an increased in cellular proliferation. The results demonstrated that the HA/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Hydrothermal synthesis of hydroxyapatite nanoparticles decorated with silver nanoparticles for application in biomaterials

Energy Technology Data Exchange (ETDEWEB)

Assis, Jordanna Fernandes; Arantes, Tatiane Moraes, E-mail: fernandes.jordanna9@gmail.com [Universidade Federal de Goias (UFG), Goiania (Brazil); Cristovan, F.H.; Tada, Dayane Batista [Universidade Federal de Sao Paulo (UNIFESP), Sao Jose dos Campos, SP (Brazil)

2016-07-01

Full text: The hydroxyapatite nanoparticles (HA) have research attention because are material that exhibit biocompatibility with bone mineral phase of human body is great interest in the scientific community. Synthetic hydroxyapatite nanoparticles have excellent biocompatibility and bioactivity, due biocompatibility and osteo inducibility [1-3]. The hydroxyapatite nanoparticles were synthesized by hydrothermal processing and were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). The XRD and Raman spectra showed crystalline hydroxyapatite colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated hydroxyapatite surface. TEM images showed HA nanoparticles presented a well defined nanorod shapes and narrow size distributions with dimensions (width and length) around of 5 nm and 50 nm decorated with silver nanoparticles of spherical shape about 20 nm in diameter The results showed that crystalline hydroxyapatite colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. These nanoparticles The cell viability of the HA and HA/Ag was analyzed by reduction of the tetrazolium salt (MTT test). Embryonic mouse fibroblast cells were grown in the presence of nanoparticles for a total period of 96 hours. Analyses were made in 24h, 48h, 72h and 96h. The suspensions at the end of each period were analyzed in spectrophotometer. The 24h experiments were the most conclusive, with the silver presence in the HA, there is an increased in cellular proliferation. The results demonstrated that the HA/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Production of silver ions from colloidal silver by nanoparticle iontophoresis system.

Science.gov (United States)

Tseng, Kuo-Hsiung; Liao, Chih-Yu

2011-03-01

Metal ions, especially the silver ion, were used to treat infection before the initiation of antibiotic therapy. Unfortunately, there is a lack of research on the metallic nanoparticle suspension as a reservoir for metal ion release application. For medical purposes, conversion of colloidal silver into an ionic form is necessary, but not using silver salts (e.g., AgNO3, Ag2SO4), due to the fact that the counter-ion of silver salts may cause problems to the body as the silver ion (Ag+) is consumed. The goal of this research is to develop a silver nanoparticle iontophoresis system (NIS) which can provide a relatively safe bactericidal silver ion solution with a controllable electric field. In this study, ion-selective electrodes were used to identify and observe details of the system's activity. Both qualitative and quantitative data analyses were performed. The experimental results show that the ion releasing peak time (R(PT)) has an inversely proportional relationship with the applied current and voltage. The ion releasing maximum level (R(ML)) and dosage (R(D)) are proportional to the current density and inversely proportional to the voltage, respectively. These results reveal that the nanoparticle iontophoresis system (NIS) is an alternative method for the controlled release of a metal ion and the ion's concentration profile, by controlling the magnitude of current density (1 microA/cm2 equal to 1 ppm/hour) and applied voltage.

Synergistic antibacterial effects of β-lactam antibiotic combined with silver nanoparticles

Science.gov (United States)

Li, Ping; Li, Juan; Wu, Changzhu; Wu, Qingsheng; Li, Jian

2005-09-01

The bactericidal action of silver (0) nanoparticles and amoxicillin on Escherichia coli is studied, respectively. Increasing concentration of both amoxicillin (0-0.525 mg ml-1) and silver nanoparticles (0-40 µg ml-1) showed a higher antibacterial effect in Luria-Bertani (LB) medium. Escherichia coli cells have different bactericidal sensitivity to them. When amoxicillin and silver nanoparticles are combined, it results in greater bactericidal efficiency on Escherichia coli cells than when they were applied separately. Dynamic tests on bacterial growth indicated that exponential and stationary phases are greatly decreased and delayed in the synergistic effect of amoxicillin and silver nanoparticles. In addition, the effect induced by a preincubation with silver nanoparticles is examined. The results show that solutions with more silver nanoparticles have better antimicrobial effects. One hypothesized mechanism is proposed to explain this phenomenon.

Raman scattering of Cisplatin near silver nanoparticles

Science.gov (United States)

Mirsaleh-Kohan, Nasrin; Duplanty, Michael; Torres, Marjorie; Moazzezi, Mojtaba; Rostovtsev, Yuri V.

2018-03-01

The Raman scattering of Cisplatin (the first generation of anticancer drugs) has been studied. In the presence of silver nanoparticles, strong modifications of Raman spectra have been observed. The Raman frequencies have been shifted and the line profiles are broadened. We develop a theoretical model to explain the observed features of the Raman scattering. The model takes into account self-consistently the interaction of molecules with surface plasmonic waves excited in the silver nanoparticles, and it provides a qualitative agreement with the observed Raman spectra. We have demonstrated that the using silver nanoparticles can increase sensitivity of the technique, and potentially it has a broader range of applications to both spectroscopy and microscopy.

Rapid Synthesis of Highly Monodisperse Au x Ag 1− x Alloy Nanoparticles via a Half-Seeding Approach

KAUST Repository

Chng, Ting Ting; Polavarapu, Lakshminarayana; Xu, Qing Hua; Ji, Wei; Zeng, Hua Chun

2011-01-01

Gold-silver alloy AuxAg1-x is an important class of functional materials promising new applications across a wide array of technological fields. In this paper, we report a fast and facile synthetic protocol for preparation of highly monodisperse Aux

Comparison on Bactericidal and Cytotoxic Effect of Silver Nanoparticles Synthesized by Different Methods

Science.gov (United States)

Mala, R.; Celsia, A. S. Ruby; Malathi Devi, S.; Geerthika, S.

2017-08-01

Biologically synthesized silver nanoparticle are biocompatible for medical applications. The present work is aimed to synthesize silver nanoparticle using the fruit pulp of Tamarindusindica and to evaluate its antibacterial and anticancer activity against lung cancercell lines. Antibacterial activity was assessed by well diffusion method. Cytotoxicity was evaluated using MTT assay. GC-MS of fruit pulp extract showed the presence of levoglucosenone, n-hexadecanoic acid, 9,12-octadecadienoic acid etc. Antioxidant activity of the fruit pulp was determined by DPPH assay, hydrogen peroxide scavenging assay and lipid peroxidation. The size of biologically synthesized silver nanoparticle varied from 50 nm to 76 nm. It was 59 nm to 98 nm for chemically synthesized silver nanoparticle. Biologically synthesized silver nanoparticle showed 26 mm inhibition zone against E. coli and chemically synthesized silver nanoparticle showed 20 mm. Antioxidant activity of fruit extract by DPPH showed 84 % reduction. The IC 50 of biologically synthesized silver nanoparticle against lung cancer cell lines was 48 µg/ml. It was 95 µg/ml for chemically synthesized silver nanoparticle. The increased activity of biologically synthesized silver nanoparticle was due to its smaller size, stability and the bioactive compounds capping the silver nanoparticle extracted from the fruit extract.

Synthesis, characterization and magnetic properties of highly monodispersed PtNi nanoparticles

International Nuclear Information System (INIS)

Du, Juan-Juan; Yang, Yi; Zhang, Rong-Hua; Zhou, Xin-Wen

2015-01-01

In this paper, we report the controlled-synthesis of PtNi nanoparticles through galvanic displacement reaction and chemical reduction. The size, composition and morphology of the products are characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), energy dispersed X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses. The structure and composition of the PtNi nanoparticles can be controlled by adjusting the synthetic conditions. The possible formation mechanism is obtained from the academic analysis and experimental studies. The results of the magnetic measurement illustrate that the PtNi nanoparticles show a superparamagnetic behavior with a blocking temperature (T B ) about 8.0 K. - Highlights: • Highly monodispersed PtNi nanoparticles were synthesized by galvanic displacement reaction. • The formation of Pt nanocrystals was the foremost step because of its self-catalysis effect. • The PtNi nanoparticles show a superparamagnetic behavior with a T B about 8.0 K

Synthesis and antibacterial activity of of silver nanoparticles

International Nuclear Information System (INIS)

Maliszewska, I; Sadowski, Z

2009-01-01

Silver nanoparticles have been known to have inhibitory and bactericidal effects but the antimicrobial mechanism have not been clearly revealed. Here, we report on the synthesis of metallic nanoparticles of silver using wild strains of Penicillium isolated from environment. Kinetics of the formation of nanosilver was monitored using the UV-Vis. TEM micrographs showed the formation of silver nanoparticles in the range 10-100 nm. Obtained Ag nanoparticles were evaluated for their antimicrobial activity against the gram-positive and gram-negative bacteria. As results, Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were effectively inhibited. Nanosilver is a promising candidate for development of future antibacterial therapies because of its wide spectrum of activity.

Studies on extracellular biosynthesis of silver nanoparticles by the fungus aspergillus niger

International Nuclear Information System (INIS)

Ibrahim, H.M.M.

2011-01-01

An eco-friendly process for the synthesis of silver nanoparticles has been attempted, using the culture filtrate of various microorganisms, included bacteria, fungi and yeast. Only fungi, especially aspergillus niger, were capable of synthesizing silver nanoparticles. The culture filtrate treated with AgNo 3 (1 mM) turned dark brown after 72 h of incubation, indicating reduction of silver ions into silver nanoparticles. This observation was confirmed with UV-vis spectroscopy analysis;a large broad band with long tail was detected at 430 nm,this band is characteristic of several metal nanoparticles.X ray diffraction revealed the crystalline nature of obtained nanoparticles. The TEM and SEM analysis showed particles spherical in shape. The average particles size determined by DLS analysis was 94.2 nm.EDX analysis indicated the presence of silver element in the nanoparticles. FT-IR analysis confirmed the presence of protein associated with the synthesized silver nanoparticles. The maximum biosynthesis of nanoparticles was achieved when the culture filtrate was treated with 4.0 mM of AgNo 3 , adjusted to ph 8.0, and incubated at 50 degree C for 96 h. Silver nanoparticles showed antibiotic activity exceeding that of silver ions against various microorganisms

Synthesis and characterization of silver nanoparticles: effect on phytopathogen Colletotrichum gloesporioides

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Mendez, Miguel A., E-mail: maguilarme@ipn.mx; San Martin-Martinez, Eduardo; Ortega-Arroyo, Lesli [Instituto Politecnico Nacional, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (Mexico); Cobian-Portillo, Georgina [Instituto Politecnico Nacional, Centro Interdisciplinario de Investigacion para el Desarrollo Integral Regional (Mexico); Sanchez-Espindola, Esther [Instituto Politecnico Nacional, Escuela Nacional de Ciencias Biologicas, Prolongacion Manuel M. Carpio s/n, esq. Plan de Ayala (Mexico)

2011-06-15

Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin as capping agent. The obtained nanoparticles were characterized by means of UV-Vis spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV-Vis spectra indicated the formation of silver nanoparticles preferably spherical and of relatively small size (<20 nm). The above-mentioned was confirmed by TEM, observing a size distribution of 5-24 nm. According to RSM the synthesis variables influenced on the size of the silver nanoparticles. By means of FTIR spectroscopy it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration. The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner.

Synthesis and characterization of silver nanoparticles: effect on phytopathogen Colletotrichum gloesporioides

International Nuclear Information System (INIS)

Aguilar-Méndez, Miguel A.; San Martín-Martínez, Eduardo; Ortega-Arroyo, Lesli; Cobián-Portillo, Georgina; Sánchez-Espíndola, Esther

2011-01-01

Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin as capping agent. The obtained nanoparticles were characterized by means of UV–Vis spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV–Vis spectra indicated the formation of silver nanoparticles preferably spherical and of relatively small size (<20 nm). The above-mentioned was confirmed by TEM, observing a size distribution of 5–24 nm. According to RSM the synthesis variables influenced on the size of the silver nanoparticles. By means of FTIR spectroscopy it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration. The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner.

Towards localization of engineered silver nanoparticles in Pseudokirchneriella subcapitata

DEFF Research Database (Denmark)

Jensen, Louise Helene Søgaard; Sørensen, Sara Nørgaard; Hartmann, Nanna Isabella Bloch

Silver nanoparticles have increased cytotoxic properties compared to larger particles. Reflecting these properties, engineered silver nanoparticles are now added to an increasing number of consumer products often labelled as anti-bacterial. These particles are presently considered the fastest...... growing nanotechnology application. Accordingly, silver nanoparticles are now postulated to be released into the sewerage systems and wider environment in increasing quantities. Here they could potentially interfere with aquatic life and this ongoing project aims to localize possible particles taken up...

Therapeutic Potential of Biologically Reduced Silver Nanoparticles from Actinomycete Cultures

International Nuclear Information System (INIS)

Sukanya, M.K.; Saju, K.A.; Praseetha, P.K.; Sakthivel, G.

2013-01-01

Silver nanoparticles are applied in nanomedicine from time immemorial and are still used as powerful antibiotic and anti-inflammatory agents. Antibiotics produced by actinomycetes are popular in almost all the therapeutic measures, and this study has proven that these microbes are also helpful in the biosynthesis of silver nanoparticles with good surface and size characteristics. Silver can be synthesized by various chemical methodologies, and most of them have turned to be toxic. This study has been successful in isolating the microbes from polluted environment, and subjecting them to the reduction of silver nanoparticles, characterizing the nanoparticles by UV spectrophotometry and transmission electron microscopy. The nanoparticles produced were tested for their antimicrobial property, and the zone of inhibition was greater than those produced by their chemically synthesized counterparts. Actinomycetes, helpful in bioremediating heavy metals, are useful for the production of metallic nanoparticles. The biosynthesized silver nanoparticles loaded with antibiotics prove to be better in killing the pathogens and have opened up new areas for developing nanobiotechnological research based on microbial applications.

Silver nanoparticles - Wolves in sheep's clothing?

DEFF Research Database (Denmark)

Foldbjerg, Rasmus Bruno; Jiang, Xiumei; Micləuş, Teodora

2015-01-01

Silver nanoparticles (Ag NPs) are one of the most widely utilized engineered nanomaterials (ENMs) in commercial products due to their effective antibacterial activity, high electrical conductivity, and optical properties. Therefore, they have been one of the most intensively investigated nanomate......Silver nanoparticles (Ag NPs) are one of the most widely utilized engineered nanomaterials (ENMs) in commercial products due to their effective antibacterial activity, high electrical conductivity, and optical properties. Therefore, they have been one of the most intensively investigated...

Highly bacterial resistant silver nanoparticles: synthesis and antibacterial activities

International Nuclear Information System (INIS)

Chudasama, Bhupendra; Vala, Anjana K.; Andhariya, Nidhi; Mehta, R. V.; Upadhyay, R. V.

2010-01-01

In this article, we describe a simple one-pot rapid synthesis route to produce uniform silver nanoparticles by thermal reduction of AgNO 3 using oleylamine as reducing and capping agent. To enhance the dispersal ability of as-synthesized hydrophobic silver nanoparticles in water, while maintaining their unique properties, a facile phase transfer mechanism has been developed using biocompatible block co-polymer pluronic F-127. Formation of silver nanoparticles is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. Hydrodynamic size and its distribution are obtained from dynamic light scattering (DLS). Hydrodynamic size and size distribution of as-synthesized and phase transferred silver nanoparticles are 8.2 ± 1.5 nm (σ = 18.3%) and 31.1 ± 4.5 nm (σ = 14.5%), respectively. Antimicrobial activities of hydrophilic silver nanoparticles is tested against two Gram positive (Bacillus megaterium and Staphylococcus aureus), and three Gram negative (Escherichiacoli, Proteusvulgaris and Shigellasonnei) bacteria. Minimum inhibitory concentration (MIC) values obtained in the present study for the tested microorganisms are found much better than those reported for commercially available antibacterial agents.

Highly bacterial resistant silver nanoparticles: synthesis and antibacterial activities

Energy Technology Data Exchange (ETDEWEB)

Chudasama, Bhupendra, E-mail: bnchudasama@gmail.co [Thapar University, School of Physics and Materials Science (India); Vala, Anjana K.; Andhariya, Nidhi; Mehta, R. V. [Bhavnagar University, Department of Physics (India); Upadhyay, R. V. [Charotar University of Science and Technology, P.D. Patel Institute of Applied Sciences (India)

2010-06-15

In this article, we describe a simple one-pot rapid synthesis route to produce uniform silver nanoparticles by thermal reduction of AgNO{sub 3} using oleylamine as reducing and capping agent. To enhance the dispersal ability of as-synthesized hydrophobic silver nanoparticles in water, while maintaining their unique properties, a facile phase transfer mechanism has been developed using biocompatible block co-polymer pluronic F-127. Formation of silver nanoparticles is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. Hydrodynamic size and its distribution are obtained from dynamic light scattering (DLS). Hydrodynamic size and size distribution of as-synthesized and phase transferred silver nanoparticles are 8.2 {+-} 1.5 nm ({sigma} = 18.3%) and 31.1 {+-} 4.5 nm ({sigma} = 14.5%), respectively. Antimicrobial activities of hydrophilic silver nanoparticles is tested against two Gram positive (Bacillus megaterium and Staphylococcus aureus), and three Gram negative (Escherichiacoli, Proteusvulgaris and Shigellasonnei) bacteria. Minimum inhibitory concentration (MIC) values obtained in the present study for the tested microorganisms are found much better than those reported for commercially available antibacterial agents.

Antituberculous effect of silver nanoparticles

International Nuclear Information System (INIS)

Kreytsberg, G N; Gracheva, I E; Kibrik, B S; Golikov, I V

2011-01-01

The in vitro experiment, involving 1164 strains of the tuberculosis mycobacteria, exhibited a potentiating effect of silver nanoparticles on known antituberculous preparations in respect of overcoming drug-resistance of the causative agent. The in vitro experiment, based on the model of resistant tuberculosis, was performed on 65 white mice. An evident antituberculous effect of the nanocomposite on the basis of silver nanoparticles and isoniazid was proved. Toxicological assessment of the of nanopreparations was carried out. The performed research scientifically establishes efficacy and safety of the nanocomposite application in combination therapy of patients suffering from drug-resistant tuberculosis.

Antituberculous effect of silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Kreytsberg, G N; Gracheva, I E [Limited Liability Company ' Scientific and Production Association (NPO)' Likom' , 150049, Yaroslavl, Magistralnaya str., 32 (Russian Federation); Kibrik, B S [Yaroslavl State Medical Academy Russia, 150000, Yaroslavl, Revolutsionnaya str., 5 (Russian Federation); Golikov, I V, E-mail: likomm@yaroslavl.ru [Yaroslavl State Technical University Russia, 150023, Yaroslavl, Moskovskiy avenue, 88 (Russian Federation)

2011-04-01

The in vitro experiment, involving 1164 strains of the tuberculosis mycobacteria, exhibited a potentiating effect of silver nanoparticles on known antituberculous preparations in respect of overcoming drug-resistance of the causative agent. The in vitro experiment, based on the model of resistant tuberculosis, was performed on 65 white mice. An evident antituberculous effect of the nanocomposite on the basis of silver nanoparticles and isoniazid was proved. Toxicological assessment of the of nanopreparations was carried out. The performed research scientifically establishes efficacy and safety of the nanocomposite application in combination therapy of patients suffering from drug-resistant tuberculosis.

Microstructural and Z-scan measurement of silver nanoparticles

International Nuclear Information System (INIS)

Sivakami, R.; Dhanuskodi, S.

2015-01-01

Graphical abstract: - Highlights: • Novel Ag nanoparticles were prepared by hydrothermal method. • The modified forms of W-H analysis of Ag nanoparticles are reported first time. • Nonlinear optical (NLO) properties of Ag nanoflowers are reported and high nonlinearity was obtained. - Abstract: Silver nanoflowers were synthesized by the hydrothermal route. Formation of Ag nanoparticles is confirmed from the UV–vis spectrum where the surface plasmon absorption maxima are observed at 415–454 nm. FE-SEM and TEM images revealed the formation of silver nanoflowers and the flower-like silver nanostructures are estimated using transmission electron microscopy. XRD confirms that the synthesized silver is highly crystalline with face centered cubic structure. The X-ray line broadening is studied by the modified forms of Williamson–Hall analysis. The Z-scan results reveal that the flower-like silver nanostructures exhibit the nonlinear susceptilibility as 1.14 × 10 −5 esu

Silver Nanoparticles (AgNP impregnated filters in drinking water disinfection

Directory of Open Access Journals (Sweden)

Rus Alexandru

2017-01-01

Full Text Available This paper describes how simple portable devices could eliminate water pathogens by using Silver Nanoparticles, based on their antimicrobial properties. Recent studies indicated that silver nanoparticles can achieve up to 100% antibacterial activity removal. Results are showing that Silver Nanoparticles retention in the filter structure, E. coli bacteria removal, water quality and water flow rate must be evaluated as main efficiency indicators of the designed filters, in order to obtain the optimal filter. To apply the antimicrobial property of Silver in drinking-water treatment, a filter is produced using Additive Manufacturing techniques and coated with different concentrations of silver solutions.

Sunlight-assisted synthesis of colloidal silver nanoparticles using chitosan as reducing agent

Science.gov (United States)

Susilowati, E.; Maryani; Ashadi

2018-04-01

The present study we explore an environmentally friendly colloidal silver nanoparticles preparation using chitosan as reducing agent and stabilizer. It develops a new strategy on preparation of silver nanoparticles through the gel phase using sodium hydroxide (NaOH) as accelerator reagent. Sunlight irradiation was employed to assisted reducing process of silver ions to silver nanoparticles. Localized surface plasmon resonance (LSPR) phenomenon of silver nanoparticles was investigated using UV-Vis spectrophotometer. The shape and size of silver particles were analyzed using TEM. The formation of silver nanoparticles was confirmed by the appearance of LSPR absorption peak at 396.0–412.0 nm. The absorption peak of LSPR were affected by NaOH amount, time of sulight irradiation and concentration of AgNO3. The produced silver nanoparticles were spherical with dominant size range of 5 to 8 nm as shown by TEM images. All colloidals were stable without any aggregation for 30 days after preparation.

Synthesis and characterization of silver nanoparticles in natural rubber

International Nuclear Information System (INIS)

Abu Bakar, N.H.H.; Ismail, J.; Abu Bakar, M.

2007-01-01

Silver nanoparticles are formed in natural rubber matrix via photo reduction of film cast from natural rubber latex (NRL) containing silver salt. The resulting NR-Ag nanocomposite is characterized using TEM, XRD and UV spectroscopic techniques. The nanoparticles, diameter ranging between 4 and 10 nm, are dispersed within distinct interfaces which correspond to the inter-particle boundaries of the NRL particles that form the matrix. The average width of the interfaces is 8 nm. X-ray diffraction (XRD) analysis confirms the nanoparticles as metallic silver of the face-centered cubic type. UV-vis absorption spectra show peaks characteristic of the surface plasmon resonance of nano-sized silver. A comparison with the results of formation of silver, obtained under similar reduction condition, in a series of matrices namely de-proteinized natural rubber latex (DNRL), NRL containing sodium dodecyl sulfate (SDS), aqueous solutions of bovain serum albumin and SDS, suggests that the protein in natural rubber is responsible for the formation of stable silver nanoparticles in the natural rubber (NR) matrix

Noble silver nanoparticles (AgNPs) synthesis and characterization ...

African Journals Online (AJOL)

Nanotechnology is rapidly growing with nanoparticles produced and utilized in a wide range of pharmaceutical and commercial products throughout the world. In this study, fig (Ficus carica) leaf extracts were used for ecofriendly extracellular synthesis of stable silver nanoparticles (AgNPs) by treating an aqueous silver ...

Biosynthesis of silver nanoparticles by Leishmania tropica | Rahi ...

African Journals Online (AJOL)

A novel biosynthesis route for Silver Nanoparticles (Ag-NPs) was attempted in the present study using Leishmania tropica the causative agent of cutaneous leishmaniasis in different countries, particularly in Mediterranean region in Iraq. Silver nanoparticles were successfully synthesized from AgNO3 by reduction of ...

Electrodeposited Silver Nanoparticles Patterned Hexagonally for SERS

International Nuclear Information System (INIS)

Gu, Geun Hoi; Lee, Sue Yeone; Suh, Jung Sang

2010-01-01

We have fabricated hexagonally patterned silver nanoparticles for surface-enhanced Raman scattering (SERS) by electrodepositing silver on the surface of an aluminum plate prepared by completely removing the oxide from anodic aluminum oxide (AAO) templates. Even after completely removing the oxide, well-ordered hexagonal patterns, similar to the shape of graphene, remained on the surface of the aluminum plate. The borders of the hexagonal pattern protruded up to form sorts of nano-mountains at both the sides and apexes of the hexagon, with the apexes protruding even more significantly than the sides. The aluminum plate prepared by completely removing the oxide has been used in the preparation of SERS substrates by sputter-coating of gold or silver on it. Instead of sputter-coating, here we have electro-deposited silver on the aluminum plate. When silver was electro-deposited on the plate, silver nanoparticles were made along the hexagonal margins.

Formation of silver microbelt structures by laser irradiation of silver nanoparticles in ethanol

Directory of Open Access Journals (Sweden)

Zamiri R

2011-10-01

Full Text Available Reza Zamiri1, Azmi Zakaria1,2, Mohd Shahril Husin1, Zaidan Abd Wahab1, Forough Kalaei Nazarpour3 1Department of Physics, Faculty of Science, 2Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, 3Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia Abstract: In the present work, we prepared silver nanoparticles by laser ablation of pure silver plate in ethanol and then irradiated the silver nanoparticles using a 532 nm Q-switched Nd:YAG pulsed laser. Transmission electron microscopic images of the sample after irradiation clearly showed formation of big structures, such as microrods and microbelts in ethanol. The obtained microbelts had a width of about 0.166 µm and a length of 1.472 µm. The reason for the formation of such a big structure is the tendency of the nanoparticles to aggregate in ethanol before irradiation, which causes fusion of the nanoparticles. Keywords: nanomaterial, laser ablation, nanoparticles

Formation of carboxymethyl cellulose hydrogel containing silver nanoparticle

Energy Technology Data Exchange (ETDEWEB)

Park, Jong Seok; Kuang, Jia; Gwon, Hui Jeong; Lim, Youn Mook; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2010-12-15

Silver nanoparticles (AgNPs) can be used in the areas such as integrate circuit, cell electrode and antimicrobial deodorant. In this study, AgNPs have been prepared by using AgNO{sub 3} aqueous solution in the carboxymethyl cellulose (CMC) hydrogel. CMC powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make CMC hydrogel. CMC hydrogels were dipped into 1.0 x 10{sup -2} M AgNO{sub 3} solution for 1 hour. After that, the swollen hydrogels were irradiated by gamma-ray for the formation of AgNPs. The characteristics of silver nanoparticles in the CMC hydrogels were monitored by UV-Vis and the morphological study and dispersed coefficient of particles were investigated by FE-SEM/EDX. It was observed that the sodium salt in the CMC is crucial to the formation of silver nanoparticle. Finally, antibacterial tests indiacted that the hydrogel containing silver nanoparticle has antibacterial activity.

Size-dependent surface plasmon resonance in silver silica nanocomposites

International Nuclear Information System (INIS)

Thomas, Senoy; Nair, Saritha K; Jamal, E Muhammad Abdul; Anantharaman, M R; Al-Harthi, S H; Varma, Manoj Raama

2008-01-01

Silver silica nanocomposites were obtained by the sol-gel technique using tetraethyl orthosilicate (TEOS) and silver nitrate (AgNO 3 ) as precursors. The silver nitrate concentration was varied for obtaining composites with different nanoparticle sizes. The structural and microstructural properties were determined by x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopic (XPS) studies were done for determining the chemical states of silver in the silica matrix. For the lowest AgNO 3 concentration, monodispersed and spherical Ag crystallites, with an average diameter of 5 nm, were obtained. Grain growth and an increase in size distribution was observed for higher concentrations. The occurrence of surface plasmon resonance (SPR) bands and their evolution in the size range 5-10 nm is studied. For decreasing nanoparticle size, a redshift and broadening of the plasmon-related absorption peak was observed. The observed redshift and broadening of the SPR band was explained using modified Mie scattering theory

Anticancer and enhanced antimicrobial activity of biosynthesizd silver nanoparticles against clinical pathogens

Science.gov (United States)

Rajeshkumar, Shanmugam; Malarkodi, Chelladurai; Vanaja, Mahendran; Annadurai, Gurusamy

2016-07-01

The present investigation shows the biosynthesis of eco-friendly silver nanoparticles using culture supernatant of Enterococcus sp. and study the effect of enhanced antimicrobial activity, anticancer activity against pathogenic bacteria, fungi and cancer cell lines. Silver nanoparticles was synthesized by adding 1 mM silver nitrate into the 100 ml of 24 h freshly prepared culture supernatant of Enterococcus sp. and were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Selected Area Diffraction X-Ray (SAED), Energy Dispersive X Ray (EDX) and Fourier Transform Infra red Spectroscopy (FT-IR). The synthesized silver nanoparticles were impregnated with commercial antibiotics for evaluation of enhanced antimicrobial activity. Further these synthesized silver nanoparticles were assessed for its anticancer activity against cancer cell lines. In this study crystalline structured nanoparticles with spherical in the size ranges from 10 to 80 nm and it shows excellent enhanced antimicrobial activity than the commercial antibiotics. The in vitro assay of silver nanoparticles on anticancer have great potential to inhibit the cell viability. Amide linkages and carboxylate groups of proteins from Enterococcus sp. may bind with silver ions and convert into nanoparticles. The activities of commercial antibiotics were enhanced by coating silver nanoparticles shows significant improved antimicrobial activity. Silver nanoparticles have the great potential to inhibit the cell viability of liver cancer cells lines (HepG2) and lung cancer cell lines (A549).

Fabrication Of Biogenic Silver Nanoparticles Using Agricultural Crop Plant Leaf Extracts

Science.gov (United States)

Rajani, P.; SriSindhura, K.; Prasad, T. N. V. K. V.; Hussain, O. M.; Sudhakar, P.; Latha, P.; Balakrishna, M.; Kambala, V.; Reddy, K. Raja

2010-10-01

Nanoparticles are being viewed as fundamental building blocks of nanotechnology. Biosynthesis of nanoparticles by plant extracts is currently under exploitation. Use of agricultural crop plant extracts for synthesis of metal nanoparticles would add a new dimension to the agricultural sector in the utilization of crop waste. Silver has long been recognized as having an inhibitory effect towards many bacterial strains and microorganisms commonly present in medical and industrial processes. Four pulse crop plants and three cereal crop plants (Vigna radiata, Arachis hypogaea, Cyamopsis tetragonolobus, Zea mays, Pennisetum glaucum, Sorghum vulgare) were used and compared for their extra cellular synthesis of metallic silver nanoparticles. Stable silver nanoparticles were formed by treating aqueous solution of AgNO3 with the plant leaf extracts as reducing agent at temperatures 50 °C-95 °C. UV-Visible spectroscopy was utilized to monitor the formation of silver nanoparticles. XRD analysis of formed silver nanoparticles revealed face centered cubic structure with (111), (200), (220) and (311) planes. SEM and EDAX analysis confirm the size of the formed silver nanoparticles to be in the range of 50-200 nm. Our proposed work offers a enviro-friendly method for biogenic silver nanoparticles production. This could provide a faster synthesis rate comparable to those of chemical methods and potentially be used in areas such as cosmetics, food and medical applications.

Microwave-assisted deposition of silver nanoparticles on bamboo pulp fabric through dopamine functionalization

Energy Technology Data Exchange (ETDEWEB)

Peng, Linghui [College of Light Industry, Textile and Food Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu (China); Guo, Ronghui, E-mail: ronghuiguo214@126.com [College of Light Industry, Textile and Food Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu (China); Lan, Jianwu [College of Light Industry, Textile and Food Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu (China); Jiang, Shouxiang [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Lin, Shaojian [Institute for Technical and Macromolecular Chemistry, University of Hamburg Bundesstrasse 45, D-20146 Hamburg (Germany)

2016-11-15

Highlights: • Silver nanoparticles were synthesized on bamboo pulp fabric using dopamine as an adhesive and reducing agent under microwave radiation. • Silver coated bamboo pulp fabric modified with dopamine has good UV protection and hydrophobic property. • Silver nanoparticles can be strongly fixed on dopamine modified bamboo pulp fabric. - Abstract: Silver nanoparticles were synthesized on bamboo pulp fabric with dopamine as the adhesive and reducing agent under microwave radiation. The silver nanoparticle coated bamboo pulp fabrics were characterized by X-ray photoelectron spectroscopy, scanning electron microscope and X-ray diffraction. Ultraviolet (UV) protection, color and water contact angles of the silver nanoparticle coated bamboo pulp fabrics were evaluated. In addition, the influences of concentrations of dopamine and treatment time on color strength (K/S values) of the silver nanoparticle coated fabric were investigated. Fastness to washing was employed to evaluate the adhesive strength between the silver coating and the bamboo pulp fabric modified with dopamine. The results show that the dopamine modified bamboo pulp fabric is evenly covered with silver nanoparticles. The silver nanoparticle coated bamboo pulp fabric modified with dopamine shows the excellent UV protection with an ultraviolet protection factor of 157.75 and the hydrophobicity with a water contact angle of 132.4°. In addition, the adhesive strength between the silver nanoparticles and bamboo pulp fabric is significantly improved. Silver nanoparticles coating on bamboo pulp fabric modified with dopamine is environmentally friendly, easy to carry out and highly efficient.

Self-supported silver nanoparticles containing bacterial cellulose membranes

International Nuclear Information System (INIS)

Barud, Hernane S.; Barrios, Celina; Regiani, Thais; Marques, Rodrigo F.C.; Verelst, Marc; Dexpert-Ghys, Jeannette; Messaddeq, Younes; Ribeiro, Sidney J.L.

2008-01-01

Hydrated bacterial cellulose (BC) membranes obtained from cultures of Acetobacter xylinum were used in the preparation of silver nanoparticles containing cellulose membranes. In situ preparation of Ag nanoparticles was achieved from the hydrolytic decomposition of silver triethanolamine (TEA) complexes. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns both lead to the observation of spherical metallic silver particles with mean diameter of 8 nm well adsorbed onto the BC fibriles

Continuous synthesis of colloidal silver nanoparticles by electrochemical discharge in aqueous solutions

International Nuclear Information System (INIS)

Tseng, Kuo-Hsiung; Chen, Yu-Chun; Shyue, Jing-Jong

2011-01-01

This article presents an electrochemical discharge (ECD) method that consists of a combination of chemical methods and electric arc discharges. In the method, 140 V is applied to an Ag electrode from a DC power supply. The arc-discharge between the electrodes produces metallic silver nanoparticles and silver ions in the aqueous solution. Compared with the original arc discharge, this ECD method creates smaller nanoparticles, prevents clumping of the nanoparticles, and shortens the production time. The citrate ions also reduce the silver ions to silver nanoparticles. In addition, the citrate ions cap the surface of the produced silver nanoparticles and the zeta potential increases. In this article, the weight loss of the electrodes and the reduction of silver ions to silver nanoparticles as a function of citrate concentration and electric conductivity of the medium are discussed. Furthermore, the properties of the colloidal silver prepared with ECD are analyzed by UV–Vis spectroscopy, dynamic light scattering, electrophoresis light scattering, and scanning electron microscopy. Finally, a continuous production apparatus is presented for the continuous production of colloidal silver.

Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.

Science.gov (United States)

Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

2014-01-01

The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined.

Rapid Biosynthesis of Silver Nanoparticles by Exploiting the Reducing Potential of Trapa bispinosa Peel Extract

International Nuclear Information System (INIS)

Pandey, S.; Mewada, A.; Thakur, M.; Shinde, S.; Shah, R.; Oza, G.; Sharon, M.

2013-01-01

Present work reports exceptionally high reducing capacity of Trapa bispinosa to synthesize monodispersed silver nanoparticles (SNPs) within 120 seconds at 30 degree C which is the shortest tenure reported for SNP synthesis using plants. Moreover, we also instigated impact of different ph values on fabrication of SNPs using visible spectroscopy with respect to time. Percentage conversion of Ag + ions into Ag was calculated using ICP-AES analysis and was found to be 97% at pH = 7. To investigate the reduction of Ag + ions to SNPs, cyclic voltammetry (CV) and open circuit potential (OCP) using 0.1M KNO 3 were performed. There was prompt reduction in cathodic and anodic currents after addition of the peel extract which indicates the reducing power of T. bispinosa peel. Stability of the SNPs was studied using flocculation parameter (FP) which was found to be least at all the pH values. FP was found to be indirectly proportional to stability of the nanoparticles

Evaluation of silver nanoparticles as a possible coccidiostat in ...

African Journals Online (AJOL)

... silver content of the livers of the silver nanoparticle group was 0.083 mg/kg compared to 0.001 mg/kg in the control group. The results of this study on the use of silver nanoparticles as a coccidiostat were therefore not conclusive, but holds promise so that further investigation is warranted. Keywords: Ag, protozoa, oocysts, ...

Facile synthesis of a silver nanoparticles/polypyrrole nanocomposite for non-enzymatic glucose determination.

Science.gov (United States)

Poletti Papi, Maurício A; Caetano, Fabio R; Bergamini, Márcio F; Marcolino-Junior, Luiz H

2017-06-01

The present work describes the synthesis of a new conductive nanocomposite based on polypyrrole (PPy) and silver nanoparticles (PPy-AgNP) based on a facile reverse microemulsion method and its application as a non-enzymatic electrochemical sensor for glucose detection. Focusing on the best sensor performance, all experimental parameters used in the synthesis of nanocomposite were optimized based on its electrochemical response for glucose. Characterization of the optimized material by FT-IR, cyclic voltammetry, and DRX measurements and TEM images showed good monodispersion of semispherical Ag nanoparticles capped by PPy structure, with size average of 12±5nm. Under the best analytical conditions, the proposed sensor exhibited glucose response in linear dynamic range of 25 to 2500μmolL -1 , with limit of detection of 3.6μmolL -1 . Recovery studies with human saliva samples varying from 99 to 105% revealed the accuracy and feasibility of a non-enzymatic electrochemical sensor for glucose determination by easy construction and low-cost. Copyright © 2017 Elsevier B.V. All rights reserved.

Intracellular Biosynthesis and Antibacterial Activity of Silver Nanoparticles Using Edible Mushrooms

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Sankaran MIRUNALINI

2012-11-01

Full Text Available The process of biosynthesis of silver nanoparticles is a simple, cost effective and eco-friendly approach. Biosynthesis of silver nanoparticles using some commonly available edible mushroom extracts and their antimicrobial activity was demonstrated in the current study. The formation of silver nanoparticles was confirmed by UV, FTIR and SEM and antibacterial activity was tested using disc diffusion method. From the results it is confirmed the successful formation of silver nanoparticles using mushroom extracts; they performed their role as a reducing and capping agent and also exhibited a potent antibacterial activity against S. aureus (gram positive bacteria. Thus the biosynthesis of silver nanoparticles using edible mushroom extract will deserve to be a good candidate as an antibacterial agent.

Green Synthesis of Silver Nanoparticles Using Pinus eldarica Bark Extract

Directory of Open Access Journals (Sweden)

Siavash Iravani

2013-01-01

Full Text Available Recently, development of reliable experimental protocols for synthesis of metal nanoparticles with desired morphologies and sizes has become a major focus of researchers. Green synthesis of metal nanoparticles using organisms has emerged as a nontoxic and ecofriendly method for synthesis of metal nanoparticles. The objectives of this study were production of silver nanoparticles using Pinus eldarica bark extract and optimization of the biosynthesis process. The effects of quantity of extract, substrate concentration, temperature, and pH on the formation of silver nanoparticles are studied. TEM images showed that biosynthesized silver nanoparticles (approximately in the range of 10–40 nm were predominantly spherical in shape. The preparation of nano-structured silver particles using P. eldarica bark extract provides an environmentally friendly option, as compared to currently available chemical and/or physical methods.

Human skin penetration of silver nanoparticles through intact and damaged skin

International Nuclear Information System (INIS)

Larese, Francesca Filon; D'Agostin, Flavia; Crosera, Matteo; Adami, Gianpiero; Renzi, Nadia; Bovenzi, Massimo; Maina, Giovanni

2009-01-01

There is a growing interest on nanoparticle safety for topical use. The benefits of nanoparticles have been shown in several scientific fields, but little is known about their potential to penetrate the skin. This study aims at evaluating in vitro skin penetration of silver nanoparticles. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin. Physiological solution was used as receiving phase and 70 μg/cm 2 of silver nanoparticles coated with polyvinylpirrolidone dispersed in synthetic sweat were applied as donor phase to the outer surface of the skin for 24 h. The receptor fluid measurements were performed by electro thermal atomic absorption spectroscopy (ETAAS). Human skin penetration was also determined by using transmission electron microscope (TEM) to verify the location of silver nanoparticles in exposed membranes. Median silver concentrations of 0.46 ng cm -2 (range -2 (range 0.43-11.6) were found in the receiving solutions of cells where the nanoparticles solution was applied on intact skin (eight cells) and on damaged skin (eight cells), respectively. Twenty-four hours silver flux permeation in damaged skin was 0.62 ± 0.2 ng cm -2 with a lag time <1 h. Our experimental data showed that silver nanoparticles absorption through intact and damaged skin was very low but detectable, and that in case of damaged skin it was possible an increasing permeation of silver applied as nanoparticles. Moreover, silver nanoparticles could be detected in the stratum corneum and the outermost surface of the epidermis by electron microscopy. We demonstrated for the first time that silver applied as nanoparticles coated with polyvinylpirrolidone is able to permeate the damaged skin in an in vitro diffusion cell system

Toxicity of silver nanoparticles in zebrafish models

Energy Technology Data Exchange (ETDEWEB)

Asharani, P V; Valiyaveettil, Suresh [Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, 117543 (Singapore); Wu Yilian; Gong Zhiyuan [Department of Biological Sciences, National University of Singapore, Science Drive 4, 117543 (Singapore)], E-mail: chmsv@nus.edu.sg

2008-06-25

This study was initiated to enhance our insight on the health and environmental impact of silver nanoparticles (Ag-np). Using starch and bovine serum albumin (BSA) as capping agents, silver nanoparticles were synthesized to study their deleterious effects and distribution pattern in zebrafish embryos (Danio rerio). Toxicological endpoints like mortality, hatching, pericardial edema and heart rate were recorded. A concentration-dependent increase in mortality and hatching delay was observed in Ag-np treated embryos. Additionally, nanoparticle treatments resulted in concentration-dependent toxicity, typified by phenotypes that had abnormal body axes, twisted notochord, slow blood flow, pericardial edema and cardiac arrhythmia. Ag{sup +} ions and stabilizing agents showed no significant defects in developing embryos. Transmission electron microscopy (TEM) of the embryos demonstrated that nanoparticles were distributed in the brain, heart, yolk and blood of embryos as evident from the electron-dispersive x-ray analysis (EDS). Furthermore, the acridine orange staining showed an increased apoptosis in Ag-np treated embryos. These results suggest that silver nanoparticles induce a dose-dependent toxicity in embryos, which hinders normal development.

Toxicity of silver nanoparticles in zebrafish models

International Nuclear Information System (INIS)

Asharani, P V; Valiyaveettil, Suresh; Wu Yilian; Gong Zhiyuan

2008-01-01

This study was initiated to enhance our insight on the health and environmental impact of silver nanoparticles (Ag-np). Using starch and bovine serum albumin (BSA) as capping agents, silver nanoparticles were synthesized to study their deleterious effects and distribution pattern in zebrafish embryos (Danio rerio). Toxicological endpoints like mortality, hatching, pericardial edema and heart rate were recorded. A concentration-dependent increase in mortality and hatching delay was observed in Ag-np treated embryos. Additionally, nanoparticle treatments resulted in concentration-dependent toxicity, typified by phenotypes that had abnormal body axes, twisted notochord, slow blood flow, pericardial edema and cardiac arrhythmia. Ag + ions and stabilizing agents showed no significant defects in developing embryos. Transmission electron microscopy (TEM) of the embryos demonstrated that nanoparticles were distributed in the brain, heart, yolk and blood of embryos as evident from the electron-dispersive x-ray analysis (EDS). Furthermore, the acridine orange staining showed an increased apoptosis in Ag-np treated embryos. These results suggest that silver nanoparticles induce a dose-dependent toxicity in embryos, which hinders normal development

Spectroscopic analysis of the riboflavin-serum albumins interaction on silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Voicescu, Mariana, E-mail: voicescu@icf.ro; Angelescu, Daniel G. [Institute of Physical Chemistry ' Ilie Murgulescu' , Romanian Academy (Romania); Ionescu, Sorana [University of Bucharest, Department of Physical Chemistry (Romania); Teodorescu, Valentin S. [Institute of Atomic Physics, National Institute of Materials Physics (Romania)

2013-04-15

Spectrophotometric behavior of riboflavin (RF) adsorbed on silver nanoparticles as well as its interaction with two serum albumins, BSA and HSA, respectively, has been evidenced. The time evolution of the plasmonic features of the complexes formed by RF/BSA/HSA and Ag(0) nanoparticles having an average diameter of 10.0 {+-} 2.0 nm have been investigated by UV-Vis absorption spectroscopy. Using steady-state and time-resolved fluorescence spectroscopy, the structure, stability, and dynamics of the serum albumins have been studied. The efficiency of energy transfer process between RF and serum albumins on silver nanoparticles has been estimated. A reaction mechanism of RF with silver nanoparticles is also proposed and the results are discussed with relevance to the involvement of the silver nanoparticles to the redox process of RF and to the RF-serum albumins interaction into a silver nanoparticles complex.

Spectroscopic analysis of the riboflavin—serum albumins interaction on silver nanoparticles

Science.gov (United States)

Voicescu, Mariana; Angelescu, Daniel G.; Ionescu, Sorana; Teodorescu, Valentin S.

2013-04-01

Spectrophotometric behavior of riboflavin (RF) adsorbed on silver nanoparticles as well as its interaction with two serum albumins, BSA and HSA, respectively, has been evidenced. The time evolution of the plasmonic features of the complexes formed by RF/BSA/HSA and Ag(0) nanoparticles having an average diameter of 10.0 ± 2.0 nm have been investigated by UV-Vis absorption spectroscopy. Using steady-state and time-resolved fluorescence spectroscopy, the structure, stability, and dynamics of the serum albumins have been studied. The efficiency of energy transfer process between RF and serum albumins on silver nanoparticles has been estimated. A reaction mechanism of RF with silver nanoparticles is also proposed and the results are discussed with relevance to the involvement of the silver nanoparticles to the redox process of RF and to the RF-serum albumins interaction into a silver nanoparticles complex.

Tagetes erecta mediated phytosynthesis of silver nanoparticles: an eco-friendly approach

Directory of Open Access Journals (Sweden)

ANIKET K. GADE

2012-11-01

Full Text Available Dhuldhaj UP, Deshmukh SD, Gade AK, Yashpal M, Rai MK. 2012. Tagetes erecta mediated phytosynthesis of silver nanoparticles:an eco-friendly approach. Nusantara Bioscience 4: 109-112. Nanotechnology is a multidisciplinary field having applications in the various fields like medicine, pharmacy, engineering and biotechnology. An important step in nanotechnology is to develop simple and eco-friendly method for the nanomaterial synthesis. Here we describe simple and eco-friendly method for synthesis of silver nanoparticles by extract of Tagetes erecta plant leaves. The phytosynthesis (synthesis by plant of silver nanoparticles was detected by color change from light-green to dark-brown. Synthesis of silver nanoparticles was confirmed by UV-Vis spectrophotometry, further characterization includes nanoparticle tracking analysis system (NTA (LM20 and transmission electron microscopy (TEM. TEM analysis confirms the synthesis of the polydispersed spherical silver nanoparticles of 20-50 n

In Vivo Toxicity of Silver Nanoparticles and Silver Ions in Zebrafish (Danio rerio

Directory of Open Access Journals (Sweden)

Katrine Bilberg

2012-01-01

Full Text Available The influence of water chemistry on characterised polyvinyl pyrrolidone- (PVP- coated silver nanoparticles (81 nm was investigated. NaCl solution series of 100–800 mg L−1 lead to initial and temporal increase in nanoparticles size, but agglomeration was limited. pH variation (5–8 had only minor influence on the hydrodynamic particle size. Acute toxicity of nanosivler to zebrafish (Danio rerio was investigated in a 48-hour static renewal study and compared with the toxicity of silver ions (AgNO3. The nanosilver and silver ion 48-hour median lethal concentration (LC50 values were 84 μg L−1 and 25 μg L−1, respectively. To investigate exposure-related stress, the fish behaviour was observed visually after 0, 3, 6, 12, 24, 27, 30, and 48 hours of both nanosilver and ionic silver treatments. These observations revealed increased rate of operculum movement and surface respiration after nanosilver exposure, suggesting respiratory toxicity. The present study demonstrates that silver nanoparticles are lethal to zebrafish.

Selective recovery of silver from waste low-temperature co-fired ceramic and valorization through silver nanoparticle synthesis.

Science.gov (United States)

Swain, Basudev; Shin, Dongyoon; Joo, So Yeong; Ahn, Nak Kyoon; Lee, Chan Gi; Yoon, Jin-Ho

2017-11-01

Considering the value of silver metal and silver nanoparticles, the waste generated during manufacturing of low temperature co-fired ceramic (LTCC) were recycled through the simple yet cost effective process by chemical-metallurgy. Followed by leaching optimization, silver was selectively recovered through precipitation. The precipitated silver chloride was valorized though silver nanoparticle synthesis by a simple one-pot greener synthesis route. Through leaching-precipitation optimization, quantitative selective recovery of silver chloride was achieved, followed by homogeneous pure silver nanoparticle about 100nm size were synthesized. The reported recycling process is a simple process, versatile, easy to implement, requires minimum facilities and no specialty chemicals, through which semiconductor manufacturing industry can treat the waste generated during manufacturing of LTCC and reutilize the valorized silver nanoparticles in manufacturing in a close loop process. Our reported process can address issues like; (i) waste disposal, as well as value-added silver recovery, (ii) brings back the material to production stream and address the circular economy, and (iii) can be part of lower the futuristic carbon economy and cradle-to-cradle technology management, simultaneously. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold

International Nuclear Information System (INIS)

Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

2014-01-01

The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO 3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. - Highlights: • The hydroxyapatite and silver nanoparticles were grown on the polyurethane scaffold • The hydroxyapatite/polyurethane acts as reducing agent, stabilizer and matrix for Ag • The samples were well characterized by SEM-EDX, XRD, XPS, UV-visible spectroscopy • The hydroxyapatite/silver polyurethane scaffold shows antibacterial property

Theoretical Studies of Optical Properties of Silver Nanoparticles

International Nuclear Information System (INIS)

Ye-Wan, Ma; Zhao-Wang, Wu; Li-Hua, Zhang; Jie, Zhang

2010-01-01

Optical properties of silver nanoparticles such as extinction, absorption and scattering efficiencies are studied based on Green's function theory. The numerical simulation results show that optical properties of silver nanoparticles are mainly dependent on their sizes and geometries; the localized plasmon resonance peak is red shifted when the dielectric constant of the particle's surrounding medium increases or when a substrate is presented. The influences of wave polarizations, the incident angles of light, the composite silver and multiply-layers on the plasmon resonance are also reported. The numerical simulation of optical spectra is a very useful tool for nanoparticle growth and characterization. (fundamental areas of phenomenology(including applications))

From silver nanoparticles to nanostructures through matrix chemistry

International Nuclear Information System (INIS)

Ayyad, Omar; Munoz-Rojas, David; Oro-Sole, Judith; Gomez-Romero, Pedro

2010-01-01

Direct in situ reduction of silver ions by a biopolymer such as agar, without any other reducing nor capping agent is shown in this article to lead either to nanoparticles (typically 12(2) nm in an optimized case) or to more complex nanostructures depending on the reaction conditions used. This approach takes advantage of the porous polymer lattice acting as a template and leads to hybrid Ag-Agar materials with long-term synergic stability. Silver acts as an antibacterial agent for agar whereas the biopolymer prevents agglomeration of the inorganic nanoparticles leading to a stable nanocomposite formed by a thermoreversible biopolymer from which silver nanoparticles can eventually be recovered.

Biosynthesis of Silver Nanoparticles Using Extracts of Mexican Medicinal Plants

Science.gov (United States)

López, J. L.; Baltazar, C.; Torres, M.; Ruız, A.; Esparza, R.; Rosas, G.

The biosynthesis of silver nanoparticles using an aqueous extract of Agastache mexicana and Tecoma stans was carried out. The AgNO3 concentration and extract concentration was varied to evaluate their influence on the nanoparticles characteristics such as size and shape. Several characterization techniques were employed. UV-Vis spectroscopy revealed the surface plasmon resonance in the range of 400-500 nm. The X-Ray diffraction results showed that the nanoparticles have a face-centered cubic structure. SEM results confirmed the formation of silver nanoparticles with spherical morphologies. Finally, the antibacterial activity of silver nanoparticles was evaluated against Escherichia coli bacteria.

Effect of silver nanoparticles on concentration of silver heavy element and growth indexes in cucumber (Cucumis sativus L. negeen)

International Nuclear Information System (INIS)

Shams, Gholamabbas; Ranjbar, Morteza; Amiri, Aliasghar

2013-01-01

The tremendous progress on nanoparticle research area has been made significant effects on the economy, society, and the environment. Silver nanoparticle is one of the most important particles in these categories. Silver nanoparticles can be converted to the heavy silver metal in water by oxidation. Moreover, in the high amounts of silver concentration, they will be accumulated in different parts of the plant. However, by changing the morphology of the plant, the production will be harmful for human consumptions. In this study, nano-powders with average 50 nm silver particles are mixed with deionized distilled water in a completely randomized design. Seven treatments with various concentrations of suspension silver nanoparticles were prepared and repeated in four different parts of the plant in a regular program of spraying. Samples were analyzed to study the growth indexes and concentration of silver in different parts of the plant. It was observed that with increasing concentration of silver nanoparticles on cucumber, the growth indexes (except pH fruit), and the concentration of silver heavy metal are increased significantly. The incremental concentration had the linear relationship with correlation coefficient 0.95 and an average of 0.617 PPM by increasing of each unit in one thousand concentration of nanosilver. Although, by increasing concentration of silver nanoparticles as spraying form, the plant morphological characteristics were improved, the concentration of silver heavy metal in various plant organs was increased. These results open a new pathway to consider the effect of nanoparticles on plant’s productions for human consumptions.

Effect of silver nanoparticles on concentration of silver heavy element and growth indexes in cucumber (Cucumis sativus L. negeen)

Energy Technology Data Exchange (ETDEWEB)

Shams, Gholamabbas, E-mail: ghs@iaushiraz.net; Ranjbar, Morteza [Shiraz Branch, Islamic Azad University, Department of Physics (Iran, Islamic Republic of); Amiri, Aliasghar [Shiraz Branch, Islamic Azad University, Department of Chemistry (Iran, Islamic Republic of)

2013-05-15

The tremendous progress on nanoparticle research area has been made significant effects on the economy, society, and the environment. Silver nanoparticle is one of the most important particles in these categories. Silver nanoparticles can be converted to the heavy silver metal in water by oxidation. Moreover, in the high amounts of silver concentration, they will be accumulated in different parts of the plant. However, by changing the morphology of the plant, the production will be harmful for human consumptions. In this study, nano-powders with average 50 nm silver particles are mixed with deionized distilled water in a completely randomized design. Seven treatments with various concentrations of suspension silver nanoparticles were prepared and repeated in four different parts of the plant in a regular program of spraying. Samples were analyzed to study the growth indexes and concentration of silver in different parts of the plant. It was observed that with increasing concentration of silver nanoparticles on cucumber, the growth indexes (except pH fruit), and the concentration of silver heavy metal are increased significantly. The incremental concentration had the linear relationship with correlation coefficient 0.95 and an average of 0.617 PPM by increasing of each unit in one thousand concentration of nanosilver. Although, by increasing concentration of silver nanoparticles as spraying form, the plant morphological characteristics were improved, the concentration of silver heavy metal in various plant organs was increased. These results open a new pathway to consider the effect of nanoparticles on plant's productions for human consumptions.

Controlled synthesis of colloidal silver nanoparticles in capillary micro-flow reactor

International Nuclear Information System (INIS)

He Shengtai; Liu Yulan; Maeda, Hideaki

2008-01-01

In this study, using a polytetrafluoroethylene (PTFE) capillary tube as a micro-flow reactor, well-dispersed colloidal silver nanoparticles were controllably synthesized with different flow rates of precursory solution. Scanning transmission electron microscopy images and UV-visible absorbance spectra showed that silver nanoparticles with large size can be prepared with slow flow rate in the PTFE capillary reactor. The effects of tube diameters on the growth of colloidal silver nanoparticles were investigated. Experiment results demonstrated that using tube with small diameter was more propitious for the controllable synthesis of silver nanoparticles with different sizes.

Green synthesis of silver nanoparticle using Bambusa arundinacea leaves

Science.gov (United States)

Kataria, Bharat; Shyam, Vasvani; Kaushik, Babiya; Vasoya, Jaydeep; Joseph, Joyce; Savaliya, Chirag; Kumar, Sumit; Parikh, Sachin P.; Thakar, C. M.; Pandya, D. D.; Ravalia, A. B.; Markna, J. H.; Shah, N. A.

2017-05-01

The synthesis of nanoparticles using ecofriendly way is an interesting area in advance nanotechnology. Silver (Ag) nanoparticles are usually synthesized by chemicals route, which are quite flammable and toxic in nature. This study deals with a biosynthesis process (environment friendly) of silver nanoparticles using Bambusa arundinacea leaves for its antibacterial activity. The formation and characterization of AgNPs was confirmed by UV-Vis spectroscopy. Silver nanoparticles were successfully synthesized from AgNO3 through a simple green route using the latex of Bambusa arundinacea leaves as reducing as well as capping agent. Scanning Electron Microscopy (SEM) study indicates the formation of grains (particles) with different size and shape.

Phytotoxicity of silver nanoparticles to Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Gubbins, Eva J. [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Batty, Lesley C., E-mail: l.c.batty@bham.ac.uk [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Lead, Jamie R. [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom)

2011-06-15

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there has been some attempt to determine the toxic effects of AgNPs, there is little information on aquatic plants which have a vital role in ecosystems. This study reports the use of Lemna minor L. clone St to investigate the phytotoxicity of AgNPs under modified OECD test conditions. AgNPs were synthesised, characterised and subsequently presented to the L. minor. Results showed that inhibition of plant growth was evident after exposure to small ({approx}20 nm) and larger ({approx}100 nm) AgNPs at low concentrations (5 {mu}g L{sup -1}) and this effect became more acute with a longer exposure time. There was a linear dose-response relationship after 14 d exposure. Using predicted environmental concentrations for wastewaters it was found that AgNPs may pose a significant potential risk to the environment. - Highlights: > Silver nanoparticles are toxic to Lemna minor at concentrations of 5 {mu}g L{sup -1}. > The effect of silver nanoparticles varies with size and concentration. > Standard toxicity tests are not appropriate for application to NPs. > Silver nanoparticles pose a potential environmental risk based on modelled environmental concentrations. - Silver nanoparticles are toxic to Lemna minor at low concentrations and constitute a significant environmental risk.

Phytotoxicity of silver nanoparticles to Lemna minor L

International Nuclear Information System (INIS)

Gubbins, Eva J.; Batty, Lesley C.; Lead, Jamie R.

2011-01-01

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there has been some attempt to determine the toxic effects of AgNPs, there is little information on aquatic plants which have a vital role in ecosystems. This study reports the use of Lemna minor L. clone St to investigate the phytotoxicity of AgNPs under modified OECD test conditions. AgNPs were synthesised, characterised and subsequently presented to the L. minor. Results showed that inhibition of plant growth was evident after exposure to small (∼20 nm) and larger (∼100 nm) AgNPs at low concentrations (5 μg L -1 ) and this effect became more acute with a longer exposure time. There was a linear dose-response relationship after 14 d exposure. Using predicted environmental concentrations for wastewaters it was found that AgNPs may pose a significant potential risk to the environment. - Highlights: → Silver nanoparticles are toxic to Lemna minor at concentrations of 5 μg L -1 . → The effect of silver nanoparticles varies with size and concentration. → Standard toxicity tests are not appropriate for application to NPs. → Silver nanoparticles pose a potential environmental risk based on modelled environmental concentrations. - Silver nanoparticles are toxic to Lemna minor at low concentrations and constitute a significant environmental risk.

Bacterial flagella as biotemplate for the synthesis of silver nanoparticle impregnated bionanomaterial

Energy Technology Data Exchange (ETDEWEB)

Gopinathan, Priya [Nanobiotechnology Laboratory, Nanotech Research Facility, PSG Institute of Advanced Studies, Coimbatore, 641004 (India); Ashok, Anuradha M. [HRTEM facility, Nanotech Research Facility, PSG Institute of Advanced Studies, Coimbatore, 641004 (India); Selvakumar, R., E-mail: selvabiotech@gmail.com [Nanobiotechnology Laboratory, Nanotech Research Facility, PSG Institute of Advanced Studies, Coimbatore, 641004 (India)

2013-07-01

The present study was carried out to synthesize one dimensional silver nanoparticle impregnated flagellar bionanomaterial. Flagella was isolated from Salmonella typhimurium and depolymerised into flagellin monomers. The flagellin monomers were repolymerised again into flagella using suitable technique. The molecular weight of native (NF) and polymerized flagella (PF) was determined using polyacrylamide gel electrophoresis. The NF and PF were used as a template, over which silver nanoparticles were impregnated using in situ chemical reduction process. The synthesized flagellar-silver nanoparticle bionanomaterials were characterized using UV–vis, FT-IR Raman and XRD spectroscopy, and High resolution transmission electron microscopy (HR-TEM). The characterization studies confirmed the attachment of silver nanoparticles over flagella and repolymerised flagella. The size of the silver nanoparticles on the flagella and repolymerised flagella varied and was in the range of 3–11 nm. I–V characteristics of the bionanomaterials were analyzed using Kethley meter which indicated the increase of conductivity after impregnation of silver nanoparticles. The results indicated that flagellar-silver nanoparticle bionanomaterials can be used as a potential one dimensional bionanomaterials for various applications.

Bacterial flagella as biotemplate for the synthesis of silver nanoparticle impregnated bionanomaterial

International Nuclear Information System (INIS)

Gopinathan, Priya; Ashok, Anuradha M.; Selvakumar, R.

2013-01-01

The present study was carried out to synthesize one dimensional silver nanoparticle impregnated flagellar bionanomaterial. Flagella was isolated from Salmonella typhimurium and depolymerised into flagellin monomers. The flagellin monomers were repolymerised again into flagella using suitable technique. The molecular weight of native (NF) and polymerized flagella (PF) was determined using polyacrylamide gel electrophoresis. The NF and PF were used as a template, over which silver nanoparticles were impregnated using in situ chemical reduction process. The synthesized flagellar-silver nanoparticle bionanomaterials were characterized using UV–vis, FT-IR Raman and XRD spectroscopy, and High resolution transmission electron microscopy (HR-TEM). The characterization studies confirmed the attachment of silver nanoparticles over flagella and repolymerised flagella. The size of the silver nanoparticles on the flagella and repolymerised flagella varied and was in the range of 3–11 nm. I–V characteristics of the bionanomaterials were analyzed using Kethley meter which indicated the increase of conductivity after impregnation of silver nanoparticles. The results indicated that flagellar-silver nanoparticle bionanomaterials can be used as a potential one dimensional bionanomaterials for various applications.

Influence of surfactant on the preparation of silver nanoparticles by polyol method

International Nuclear Information System (INIS)

Dung Dang, Thi My; Tuyet Le, Thi Thu; Dang, Mau Chien; Fribourg-Blanc, Eric

2012-01-01

In this study, silver nanoparticles were synthesized from silver nitrate via a polyol method in ambient atmosphere. In our synthesis route, polyvinylpyrrolidone (PVP) is used as both size controller and capping agent, ethylene glycol acts both as solvent and reducing agent. The obtained silver nanoparticles were characterized by ultraviolet-visible spectrophotometry which indicated the formation of nanoparticles. Investigation of Fourier transform infrared spectroscopy clearly demonstrated the coordination between silver nanoparticles and PVP. Transmission electron microscopy (TEM) contributed to the particle size analysis. The surface plasmon resonance peak in absorption spectra of silver colloidal solution showed absorption from 406 to 409 nm. The average size of the resulting silver nanoparticles was below 10 nm with a dependency on the PVP concentration. (paper)

Bacterial resistance to silver nanoparticles and how to overcome it

Science.gov (United States)

Panáček, Aleš; Kvítek, Libor; Smékalová, Monika; Večeřová, Renata; Kolář, Milan; Röderová, Magdalena; Dyčka, Filip; Šebela, Marek; Prucek, Robert; Tomanec, Ondřej; Zbořil, Radek

2018-01-01

Silver nanoparticles have already been successfully applied in various biomedical and antimicrobial technologies and products used in everyday life. Although bacterial resistance to antibiotics has been extensively discussed in the literature, the possible development of resistance to silver nanoparticles has not been fully explored. We report that the Gram-negative bacteria Escherichia coli 013, Pseudomonas aeruginosa CCM 3955 and E. coli CCM 3954 can develop resistance to silver nanoparticles after repeated exposure. The resistance stems from the production of the adhesive flagellum protein flagellin, which triggers the aggregation of the nanoparticles. This resistance evolves without any genetic changes; only phenotypic change is needed to reduce the nanoparticles' colloidal stability and thus eliminate their antibacterial activity. The resistance mechanism cannot be overcome by additional stabilization of silver nanoparticles using surfactants or polymers. It is, however, strongly suppressed by inhibiting flagellin production with pomegranate rind extract.

Synthesis, characterization and antimicrobial activity of dextran stabilized silver nanoparticles in aqueous medium.

Science.gov (United States)

Bankura, K P; Maity, D; Mollick, M M R; Mondal, D; Bhowmick, B; Bain, M K; Chakraborty, A; Sarkar, J; Acharya, K; Chattopadhyay, D

2012-08-01

A simple one-step rapid synthetic route is described for the preparation of silver nanoparticles by reduction of silver nitrate (AgNO3) using aqueous dextran solution which acts as both reducing and capping agent. The formation of silver nanoparticles is assured by characterization with UV-vis spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The absorbance of the silver nanoparticles is observed at 423 nm. The AFM image clearly shows the surface morphology of the well-dispersed silver nanoparticles with size range of 10-60 nm. TEM images show that the nanoparticles are spherical in shape with ∼5-10 nm dimensions. The crystallinity of Ag nanoparticles is assured by XRD analysis. The antimicrobial activity of as synthesized silver nanoparticles is tested against the bacteria, Bacillus subtilis, Bacillus cereus, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The bacterial growth is inhibited by gradual reduction of the concentration of the silver nanoparticles. Copyright © 2012 Elsevier Ltd. All rights reserved.

Glass frits coated with silver nanoparticles for silicon solar cells

International Nuclear Information System (INIS)

Li, Yingfen; Gan, Weiping; Zhou, Jian; Li, Biyuan

2015-01-01

Graphical abstract: - Highlights: • Silver-coated glass frits for solar cells were prepared by electroless plating. • Gum Arabic was used as the activating agent of glass frits. • Silver-coated glass frits can improve the photovoltaic performances of solar cells. - Abstract: Glass frits coated with silver nanoparticles were prepared by electroless plating. Gum Arabic (GA) was used as the activating agent of glass frits without the assistance of stannous chloride or palladium chloride. The silver-coated glass frits prepared with different GA dosages were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The characterization results indicated that silver-coated glass frits had the structures of both glass and silver. Spherical silver nanoparticles were distributed on the glass frits evenly. The density and particle size of silver nanoparticles on the glass frits can be controlled by adjusting the GA dosage. The silver-coated glass frits were applied to silver pastes to act as both the densification promoter and silver crystallite formation aid in the silver electrodes. The prepared silver-coated glass frits can improve the photovoltaic performances of solar cells

Glass frits coated with silver nanoparticles for silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Li, Yingfen, E-mail: lyf350857423@163.com; Gan, Weiping; Zhou, Jian; Li, Biyuan

2015-06-30

Graphical abstract: - Highlights: • Silver-coated glass frits for solar cells were prepared by electroless plating. • Gum Arabic was used as the activating agent of glass frits. • Silver-coated glass frits can improve the photovoltaic performances of solar cells. - Abstract: Glass frits coated with silver nanoparticles were prepared by electroless plating. Gum Arabic (GA) was used as the activating agent of glass frits without the assistance of stannous chloride or palladium chloride. The silver-coated glass frits prepared with different GA dosages were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The characterization results indicated that silver-coated glass frits had the structures of both glass and silver. Spherical silver nanoparticles were distributed on the glass frits evenly. The density and particle size of silver nanoparticles on the glass frits can be controlled by adjusting the GA dosage. The silver-coated glass frits were applied to silver pastes to act as both the densification promoter and silver crystallite formation aid in the silver electrodes. The prepared silver-coated glass frits can improve the photovoltaic performances of solar cells.

Green Synthesis of Silver Nanoparticles Using Avena sativa L. Extract

Directory of Open Access Journals (Sweden)

Nooshin Amini

2017-02-01

Full Text Available Objective(s: Nowadays, nanoparticles bio production, considering their performance in medicine and biological science, is increasing. Green synthesis of metal nanoparticles using organisms has emerged as a nontoxic and ecofriendly method for synthesis of metal nanoparticles The objectives of this study were the production of silver nanoparticles using Avena sativa L. extract and optimization of the biosynthesis process. The effects of quantity of substrate (silver nitrate (AgNo3 and temperature on the formation of silver nanoparticles are studied. Methods: In this work, silver nanoparticles were synthesized from an extract of Avena sativa L. at different temperatures (30° C, 60° C, 90° C  and AgNo3 concentrations( 1 mM, 2mM, 4mM . The morphology and size of the nanoparticles were determined using Scanning Electron Microscope (SEM and Dynamic Light Scattering (DLS. Results: SEM images showed that by increasing temperature nanoparticles size were decreased and by increasing concentrations of AgNo3 the number of nanoparticles was increased. Conclusions: The results indicated that by increasing the reaction temperature, the size of the nanoparticles would decrease. Also by increasing the concentrations of AgNo3, the amount of produced nanoparticles would be increased, but won't have a significant effect on its size. The preparation of nano- structured silver particles using Avena sativa L. extract provides an environmentally friendly option as compared to currently available chemical/ physical methods.

Production of silver nanoparticles by laser ablation in open air

International Nuclear Information System (INIS)

Boutinguiza, M.; Comesaña, R.; Lusquiños, F.; Riveiro, A.; Val, J. del; Pou, J.

2015-01-01

Highlights: • Silver nanoparticles have been obtained by laser ablation of metallic Ag in open air using nanosecond laser. • The continuous process enables increasing the production yield. • The obtained particles are rounded shape with narrow size distribution. - Abstract: Silver nanoparticles have attracted much attention as a subject of investigation due to their well-known properties, such as good conductivity, antibacterial and catalytic effects, etc. They are used in many different areas, such as medicine, industrial applications, scientific investigation, etc. There are different techniques for producing Ag nanoparticles, chemical, electrochemical, sonochemical, etc. These methods often lead to impurities together with nanoparticles or colloidal solutions. In this work, laser ablation of solids in open air conditions (LASOA) is used to produce silver nanoparticles and collect them on glass substrates. Production and deposition of silver nanoparticles are integrated in the same step to reduce the process. The obtained particles are analysed and the nanoparticles formation mechanism is discussed. The obtained nanoparticles were characterized by means of transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV/VIS absorption spectroscopy. The obtained nanoparticles consisted of Ag nanoparticles showing rounded shape with diameters ranging from few to 50 nm

Production of silver nanoparticles by laser ablation in open air

Energy Technology Data Exchange (ETDEWEB)

Boutinguiza, M., E-mail: mohamed@uvigo.es [Applied Physics Department, University of Vigo EEI, Lagoas-Marcosende, 9. Vigo, 36310 (Spain); Comesaña, R. [Materials Engineering, Applied Mechanics and Construction Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo, 36310 (Spain); Lusquiños, F.; Riveiro, A.; Val, J. del; Pou, J. [Applied Physics Department, University of Vigo EEI, Lagoas-Marcosende, 9. Vigo, 36310 (Spain)

2015-05-01

Highlights: • Silver nanoparticles have been obtained by laser ablation of metallic Ag in open air using nanosecond laser. • The continuous process enables increasing the production yield. • The obtained particles are rounded shape with narrow size distribution. - Abstract: Silver nanoparticles have attracted much attention as a subject of investigation due to their well-known properties, such as good conductivity, antibacterial and catalytic effects, etc. They are used in many different areas, such as medicine, industrial applications, scientific investigation, etc. There are different techniques for producing Ag nanoparticles, chemical, electrochemical, sonochemical, etc. These methods often lead to impurities together with nanoparticles or colloidal solutions. In this work, laser ablation of solids in open air conditions (LASOA) is used to produce silver nanoparticles and collect them on glass substrates. Production and deposition of silver nanoparticles are integrated in the same step to reduce the process. The obtained particles are analysed and the nanoparticles formation mechanism is discussed. The obtained nanoparticles were characterized by means of transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV/VIS absorption spectroscopy. The obtained nanoparticles consisted of Ag nanoparticles showing rounded shape with diameters ranging from few to 50 nm.

Synthesis of silver nanoparticle using Portulaca oleracea L. extracts

Directory of Open Access Journals (Sweden)

Shahbazi Nafeseh

2013-09-01

Full Text Available   Objective(s: To evaluate the influences of aqueous extracts of plant parts (stem, leaves, and root of Portulaca oleracea L. on bioformation of silver nanoparticles (AgNPs.   Materials and Methods: Synthesis of silver nanoparticles by different plant part extracts of Portulaca oleracea L. was carried out and formation of nanoparticles were confirmed and evaluated using UV-Visible spectroscopy and AFM. Results: The plant extracts exposed with silver nitrate showed gradual change in color of the extract from yellow to dark brown. Different silver nanoperticles were formed using extracts of different plant parts. Conclusion: It seems that the plant parts differ in their ability to act as a reducing and capping agent.

Biosynthesis of silver nanoparticles | Silambarasan | African Journal ...

African Journals Online (AJOL)

friendly and exciting approach. Several microorganisms have been known to produce silver nanoparticles (Ag NPs), when silver molecules are exposed either intracellularly or extracellularly. Intracellular synthesis may accomplish a better ...

Nanoparticles and their tailoring with laser light

International Nuclear Information System (INIS)

Hubenthal, Frank

2009-01-01

Monodisperse noble metal nanoparticles are of tremendous interest for numerous applications, such as surface-enhanced Raman spectroscopy, catalysis or biosensing. However, preparation of monodisperse metal nanoparticles is still a challenging task, because typical preparation methods yield nanoparticle ensembles with broad shape and/or size distributions. To overcome this drawback, tailoring of metal nanoparticles with laser light has been developed, which is based on the pronounced shape- and size-dependent optical properties of metal nanoparticles. I will demonstrate that nanoparticle tailoring with ns-pulsed laser light is a suitable method to prepare nanoparticle ensembles with a narrow shape and/or size distribution. While irradiation with ns-pulsed laser light during nanoparticle growth permits a precise shape tailoring, post-grown irradiation allows a size tailoring. For example, the initial broad Gaussian size distribution of silver nanoparticles on quartz substrates with a standard deviation of σ= 30% is significantly reduced to as little as σ= 10% after tailoring. This paper addresses teachers of undergraduate and advanced school level as well as students. It assumes some fundamental knowledge in solid-state physics, thermodynamics and resonance vibration.

Cytotoxic Effect on Cancerous Cell Lines by Biologically Synthesized Silver Nanoparticles

Directory of Open Access Journals (Sweden)

Balaji Kulandaivelu

Full Text Available The biosynthesis of nanoparticles has been proposed as an environmental friendly and cost effective alternative to chemical and physical methods. Silver nanoparticles are biologically synthesized and characterized were used in the study. The invitro cytotoxic effect of biologically synthesized silver nanoparticles against MCF-7 cancer cell lines were assessed. The cytotoxic effects of the silver nanoparticles could significantly inhibited MCF-7 cancer cell lines proliferation in a time and concentration-dependent manner by MTT assay. Acridine orange, ethidium bromide (AO/EB dual staining, caspase-3 and DNA fragmentation assays were carried out using various concentrations of silver nanoparticles ranging from 1 to 100 μg/mL. At 100 μg/mL concentration, the silver nanoparticles exhibited significant cytotoxic effects and the apoptotic features were confirmed through caspase-3 activation and DNA fragmentation assays. Western blot analysis has revealed that nanoparticle was able to induce cytochrome c release from the mitochondria, which was initiated by the inhibition of Bcl-2 and activation of Bax. Thus, the results of the present study indicate that biologically synthesized silver nanoparticles might be used to treat breast cancer. The present studies suggest that these nanoparticles could be a new potential adjuvant chemotherapeutic and chemo preventive agent against cytotoxic cells. However, it necessitates clinical studies to ascertain their potential as anticancer agents.

Novel method for synthesis of silver nanoparticles and their application on wool

Energy Technology Data Exchange (ETDEWEB)

Boroumand, Majid Nasiri [Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Montazer, Majid [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Simon, Frank [Leibniz-Institut für Polymerforschung Dresden e.V., Dresden (Germany); Liesiene, Jolanta [Faculty of Chemical Technology, Kaunas University of Technology, Kaunas (Lithuania); Šaponjic, Zoran [Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade (Serbia); Dutschk, Victoria, E-mail: v.dutschk@utwente.nl [Faculty of Engineering Technology, University of Twente, Enschede (Netherlands)

2015-08-15

Graphical abstract: Tentative mechanism for reduction of Ag{sup +} by polyphenols having two hydroxy groups in ortho-position – the use of silver nanoparticles and an aqueous solution of extracted dye from Pomegranate peel as a reducing agent for synthesis silver nanoparticles from silver nitrate. - Highlights: • A new method for the synthesis of silver nanoparticles suitable to impart antibacterial properties of wool fabric proposed. • Silver nanopartilces were synthesized by a biochemical reduction method. • An aqueous solution of extracted dye from Pomegranate peel was used as a reducing agent for synthesis of silver nanoparticles from silver nitrate. - Abstract: In this study, a new method for the synthesis of silver nanoparticles (AgNPs) suitable to impart antibacterial properties of wool fabric is proposed. AgNPs were synthesized by a biochemical reduction method. An aqueous solution of extracted dye from Pomegranate peel was used as a reducing agent for the synthesis of AgNPs from silver nitrate. The ratio of dye to silver nitrate concentration (R{sub Dye}/{sub Ag} = [Dye]/[AgNO{sub 3}]) is the influencing factor in the synthesis of silver nanoparticles. The nanoparticles formation was followed by UV/Vis absorption spectroscopy. The size and shape of AgNPs were studied by transmission electron microscopy (TEM). The size distribution and Zetapotential of nanoparticles were evaluated using diffraction light scattering (DLS) measurements. The antibacterial potential of biosynthesized silver nanoparticles against Escherichia coli (E. coli) was examined qualitatively and quantitatively. Kinetic analysis of the bacteria reduction using AgNPs synthesized in different way was performed. AgNPs were applied on wool fabrics by exhaustion. The changes in surface morphology of wool fibers after AgNPs loading were studied using scanning electron microscopy (SEM). The amounts of silver deposited on wool fabrics at different pH and temperature were compared applying

Novel method for synthesis of silver nanoparticles and their application on wool

International Nuclear Information System (INIS)

Boroumand, Majid Nasiri; Montazer, Majid; Simon, Frank; Liesiene, Jolanta; Šaponjic, Zoran; Dutschk, Victoria

2015-01-01

Graphical abstract: Tentative mechanism for reduction of Ag + by polyphenols having two hydroxy groups in ortho-position – the use of silver nanoparticles and an aqueous solution of extracted dye from Pomegranate peel as a reducing agent for synthesis silver nanoparticles from silver nitrate. - Highlights: • A new method for the synthesis of silver nanoparticles suitable to impart antibacterial properties of wool fabric proposed. • Silver nanopartilces were synthesized by a biochemical reduction method. • An aqueous solution of extracted dye from Pomegranate peel was used as a reducing agent for synthesis of silver nanoparticles from silver nitrate. - Abstract: In this study, a new method for the synthesis of silver nanoparticles (AgNPs) suitable to impart antibacterial properties of wool fabric is proposed. AgNPs were synthesized by a biochemical reduction method. An aqueous solution of extracted dye from Pomegranate peel was used as a reducing agent for the synthesis of AgNPs from silver nitrate. The ratio of dye to silver nitrate concentration (R Dye / Ag = [Dye]/[AgNO 3 ]) is the influencing factor in the synthesis of silver nanoparticles. The nanoparticles formation was followed by UV/Vis absorption spectroscopy. The size and shape of AgNPs were studied by transmission electron microscopy (TEM). The size distribution and Zetapotential of nanoparticles were evaluated using diffraction light scattering (DLS) measurements. The antibacterial potential of biosynthesized silver nanoparticles against Escherichia coli (E. coli) was examined qualitatively and quantitatively. Kinetic analysis of the bacteria reduction using AgNPs synthesized in different way was performed. AgNPs were applied on wool fabrics by exhaustion. The changes in surface morphology of wool fibers after AgNPs loading were studied using scanning electron microscopy (SEM). The amounts of silver deposited on wool fabrics at different pH and temperature were compared applying energy

Biosynthesis of silver nanoparticles by a Bacillus sp. of marine origin

Science.gov (United States)

Janardhanan, A.; Roshmi, T.; Varghese, Rintu T.; Soniya, E. V.; Mathew, Jyothis; Radhakrishnan, E. K.

2013-04-01

This study was aimed to explore the nanoparticle synthesizing properties of a silver resistant Bacillus sp. isolated from a marine water sample. The 16SrDNA sequence analysis of the isolate proved it as a Bacillus strain. Very interestingly, the isolate was found to have the ability to form intracellular silver nanoparticles at room temperature within 24 hours. This was confirmed by the UV-Vis absorption analysis which showed a peak at 430 nm corresponding to the plasmon absorbance of silver nanoparticles. Further characterization of the nanoparticles was carried out by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analysis. The presence of silver nanoparticles with the size less than 100 nm was confirmed. These particles were found to be extremely stable as confirmed by the TEM analysis after three months of purification. So, the current study is the demonstration of an efficient synthesis of stable silver nanoparticles by a marine Bacillus strain.

Amperometric Sensor Used for Determination of Thiocyanate with a Silver Nanoparticles Modified Electrode

OpenAIRE

Wang, Guang-Feng; Li, Mao-Guo; Gao, Ying-Chun; Fang, Bin

2004-01-01

Abstract: A novel electrode modified with silver nanoparticles was fabricated. It is found that the reducibility of silver nanoparticles is higher than for bulk silver by comparing a silver nanoparticles modified electrode with a silver micro-disk electrode. When SCN- was added, a new oxidation peak occurred and the anodic peak current of silver nanoparticles decreased. The new anodic peak current is proportional to the thiocyanate concentration in the range of 5.0×10-7~4.0×10-4 mol/L i...

Rapid green synthesis of silver nanoparticles and nanorods using Piper nigrum extract

International Nuclear Information System (INIS)

Mohapatra, Bandita; Kuriakose, Sini; Mohapatra, Satyabrata

2015-01-01

Highlights: • Silver nanorods were synthesized by photoreduction using Piper nigrum extract. • The morphological and structural properties were studied by XRD and AFM. • Silver nanoparticles were formed at lower AgNO 3 concentration. • Increase in AgNO 3 concentration resulted in formation of silver nanorods. - Abstract: We report sun light driven rapid green synthesis of stable aqueous dispersions of silver nanoparticles and nanorods at room temperature using photoreduction of silver ions with Piper nigrum extract. Silver nanoparticles were formed within 3 min of sun light irradiation following addition of Piper nigrum extract to the AgNO 3 solution. The effects of AgNO 3 concentration and irradiation time on the formation and plasmonic properties of biosynthesized silver nanoparticles were studied using UV–visible absorption spectroscopy. The morphology and structure of silver nanoparticles were well characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). The size of Ag nanoparticles increased with increase in irradiation time, leading to the formation of anisotropic nanostructures. Increasing the AgNO 3 concentration resulted in the formation of Ag nanorods. UV–visible absorption studies revealed the presence of surface plasmon resonance (SPR) peaks which red shift and broaden with increasing AgNO 3 concentration. We have demonstrated a facile, energy efficient and rapid green synthetic route to synthesize stable aqueous dispersions of silver nanoparticles and nanorods

Rapid green synthesis of silver nanoparticles and nanorods using Piper nigrum extract

Energy Technology Data Exchange (ETDEWEB)

Mohapatra, Bandita [Multifunctional Nanomaterials Laboratory, School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); Kuriakose, Sini [Multifunctional Nanomaterials Laboratory, School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); Mohapatra, Satyabrata, E-mail: smiuac@gmail.com [Multifunctional Nanomaterials Laboratory, School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India); School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078 (India)

2015-07-15

Highlights: • Silver nanorods were synthesized by photoreduction using Piper nigrum extract. • The morphological and structural properties were studied by XRD and AFM. • Silver nanoparticles were formed at lower AgNO{sub 3} concentration. • Increase in AgNO{sub 3} concentration resulted in formation of silver nanorods. - Abstract: We report sun light driven rapid green synthesis of stable aqueous dispersions of silver nanoparticles and nanorods at room temperature using photoreduction of silver ions with Piper nigrum extract. Silver nanoparticles were formed within 3 min of sun light irradiation following addition of Piper nigrum extract to the AgNO{sub 3} solution. The effects of AgNO{sub 3} concentration and irradiation time on the formation and plasmonic properties of biosynthesized silver nanoparticles were studied using UV–visible absorption spectroscopy. The morphology and structure of silver nanoparticles were well characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). The size of Ag nanoparticles increased with increase in irradiation time, leading to the formation of anisotropic nanostructures. Increasing the AgNO{sub 3} concentration resulted in the formation of Ag nanorods. UV–visible absorption studies revealed the presence of surface plasmon resonance (SPR) peaks which red shift and broaden with increasing AgNO{sub 3} concentration. We have demonstrated a facile, energy efficient and rapid green synthetic route to synthesize stable aqueous dispersions of silver nanoparticles and nanorods.

Size-dependent structure of silver nanoparticles under high pressure

Energy Technology Data Exchange (ETDEWEB)

Koski, Kristie Jo [Univ. of California, Berkeley, CA (United States)

2008-12-31

Silver noble metal nanoparticles that are<10 nm often possess multiply twinned grains allowing them to adopt shapes and atomic structures not observed in bulk materials. The properties exhibited by particles with multiply twinned polycrystalline structures are often far different from those of single-crystalline particles and from the bulk. I will present experimental evidence that silver nanoparticles<10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. Results for nanoparticles in the intermediate size range of 5 to 10 nm suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. I propose a mechanism for this transitiion that considers the bond-length distribution in idealized multiply twinned icosahedral particles. Results for nanoparticles of 3.9 nm suggest a reversible linear pressure-dependent orthorhombic distortion. This distortion is interpreted in the context of idealized decahedral particles. In addition, given these size-dependent measurements of silver nanoparticle compression with pressure, we have constructed a pressure calibration curve. Encapsulating these silver nanoparticles in hollow metal oxide nanospheres then allows us to measure the pressure inside a nanoshell using x-ray diffraction. We demonstrate the measurement of pressure gradients across nanoshells and show that these nanoshells have maximum resolved shear strengths on the order of 500 MPa to IGPa.

Growth and galvanic replacement of silver nanocubes in organic media

Science.gov (United States)

Polavarapu, Lakshminarayana; Liz-Marzán, Luis M.

2013-05-01

Although metal nanoparticles with various shapes can be prepared in polar organic solvents, little has been advanced toward the shape-controlled synthesis in non-polar solvents. We report a simple method for the synthesis of nearly monodisperse single crystalline silver nanocubes in a non-polar solvent (1,2-dichlorobenzene) by using oleylamine as both a reducing and capping agent. Mechanistic studies based on the time evolution of Ag nanoparticles revealed that multiply twinned nanocrystals form at the beginning of the reaction, which are gradually transformed into single crystalline Ag nanocubes by oxidative etching. Control experiments showed that the solvent plays an important role in the formation of such single crystalline Ag nanocubes. The effects of reaction temperature, oleylamine concentration, solvent, and the nature of the silver ion precursor on the morphology and monodispersity of the nanoparticles were systematically investigated. Additionally, the galvanic replacement reaction with HAuCl4 in an organic medium was implemented to prepare hydrophobic hollow Au-Ag nanocages with tunable localized surface plasmon resonances.Although metal nanoparticles with various shapes can be prepared in polar organic solvents, little has been advanced toward the shape-controlled synthesis in non-polar solvents. We report a simple method for the synthesis of nearly monodisperse single crystalline silver nanocubes in a non-polar solvent (1,2-dichlorobenzene) by using oleylamine as both a reducing and capping agent. Mechanistic studies based on the time evolution of Ag nanoparticles revealed that multiply twinned nanocrystals form at the beginning of the reaction, which are gradually transformed into single crystalline Ag nanocubes by oxidative etching. Control experiments showed that the solvent plays an important role in the formation of such single crystalline Ag nanocubes. The effects of reaction temperature, oleylamine concentration, solvent, and the nature of the

Green Synthesis and Antibacterial Effect of Silver Nanoparticles Using Vitex Negundo L.

Directory of Open Access Journals (Sweden)

Fatima Abu Bakar

2011-08-01

Full Text Available Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs due to their multiple applications. One of the most important applications of Ag-NPs is their use as an anti-bacterial agent. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the biosynthesis of silver nanoparticles using Vitex negundo L. extract and its antimicrobial properties has been reported. The resulting silver particles are characterized using transmission electron microscopy (TEM, X-ray diffraction (XRD and UV–Visible (UV-Vis spectroscopic techniques. The TEM study showed the formation of silver nanoparticles in the 10–30 nm range and average 18.2 nm in size. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc structure. The silver nanoparticles showed the antimicrobial activity against Gram positive and Gram negative bacteria. Vitex negundo L. was found to display strong potential for the synthesis of silver nanoparticles as antimicrobial agents by rapid reduction of silver ions (Ag+ to Ag0.

Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

International Nuclear Information System (INIS)

Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A.; Landero-Figueroa, Julio

2014-01-01

The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag + ) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg −1 detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm

Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

Energy Technology Data Exchange (ETDEWEB)

Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A., E-mail: joseph.caruso@uc.edu; Landero-Figueroa, Julio

2014-10-01

The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag{sup +}) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg{sup −1} detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm.

Silver nanoparticles from silver halide photography to plasmonics

CERN Document Server

Tani, Tadaaki

2015-01-01

This book provides systematic knowledge and ideas on nanoparticles of Ag and related materials. While Ag and metal nanoparticles are essential for plasmonics, silver halide (AgX) photography relies to a great extent on nanoparticles of Ag and AgX which have the same crystal structure and have been studied extensively for many years. This book has been written to combine the knowledge of nanoparticles of Ag and related materials in plasmonics and AgX photography in order to provide new ideas for metal nanoparticles in plasmonics. Chapters 1–3 of this book describe the structure and formation of nanoparticles of Ag and related materials. Systematic descriptions of the structure and preparation of Ag, Au, and noble-metal nanoparticles for plasmonics are followed by and related to those of nanoparticles of Ag and AgX in AgX photography. Knowledge of the structure and preparation of Ag and AgX nanoparticles in photography covers nanoparticles with widely varying sizes, shapes, and structures, and formation proce...

Assessing antibacterial effect of filter media coated with silver nanoparticles against Bacillus spp

Directory of Open Access Journals (Sweden)

Mahmood Nafisi Bahabadi

2016-04-01

Full Text Available Background: Nanotechnology is a field of applied science and technology covering a broad range of topics. Use of nanotechnology and especially silver nanoparticles in control of bacterial diseases and infections has been studied in the recent years. The aim of the present study was to investigate the in vitro antibacterial effect of filter media coated with silver nanoparticles against Bacillus spp. Materials and methods: In this research, first, the antibacterial effects of silver nanoparticles against mentioned bacteria were evaluated by microdilution method in Broth medium. After confidence of inhibitory effect of colloidal silver nanoparticles, antibacterial effect of filter media coated with silver nanoparticles was evaluated via in vitro microbiology tests (zone of inhibition test and test tube test. Results: Present study showed that colloidal silver nanoparticles have good antimicrobial effects against tested bacteria, so that MIC and MBC of silver nanoparticles for Bacillus spp. were calculated 3.9 and 31.25 mg/L, respectively. Also significant decrease was observed in bacterial growth after exposure to filter media coated with silver nanoparticles in test tube test and  zone of inhibition test (P≤ 5%. Conclusion: The results of this research indicate that filter media coated with silver nanoparticles have considerable antimicrobial effects; therefore they could possibly be used as excellent antibacterial water filters and would have several applications in other sectors.

Gamma-irradiation assisted seeded growth of Ag nanoparticles within PVA matrix

International Nuclear Information System (INIS)

Eisa, Wael H.; Abdel-Moneam, Yasser K.; Shaaban, Yasser; Abdel-Fattah, Atef A.; Abou Zeid, Amira M.

2011-01-01

Highlights: → Nucleation and growth must be two completely separated steps. → The amount of zerovalent nuclei can be controlled by varying the irradiation dose. → PVA act as physical barrier to inhibit aggregation or the growth of Ag nanoparticles. - Abstract: Polyvinyl alcohol (PVA)/Ag hybrid nanocomposites have been prepared from polymeric film of PVA and silver nitrate (AgNO 3 ). The silver nanoparticles were generated in PVA matrix by the reduction of silver ions with gamma-irradiation. UV-visible spectra showed a single peak at 422 nm, arising from the surface plasmon absorption of silver nanoparticles. The shifting of surface plasmon resonance peak after irradiation reveals that the gamma irradiation can be used as a size controlling agent for the preparation of silver nanoparticles embedded in PVA film. This result was in good agreement with the result obtained from TEM images. The TEM images showed the narrow size distribution of the obtained Ag nanoparticles with average particle size of 30 nm, which decreased to 17 nm with increasing irradiation dose. The X-ray diffraction analysis revealed that silver metal was present in face centered cubic (fcc) crystal structure. These results clearly indicate that monodispersed silver nanoparticles are embedded homogenously in PVA matrix.

Sustainability of silver nanoparticles in solutions and polymer materials

International Nuclear Information System (INIS)

Khaydarov, R.R.; Malikov, Sh.; Khaydarov, R.A.; Mironov, V.V.

2006-01-01

The technology of obtaining stable silver nanoparticles in solutions and composite materials for attainment of antimicrobial and antifungal properties to different surfaces has been developed. The shape of particles is spherical, diameter is about 5 nm. Various concentrations of silver nanoparticles have been deposited onto surfaces of different materials (cotton and synthetic fabrics, fibroid sorbents and polymer materials). Different ways of treatment and densities of nanoparticles on the treated surface have been studied during 6 months with respect to the best sustainability. In order to prevent agglomeration of obtained metal nanoparticles on the surface of materials treated, stabilizing reagents (ethylene glycol, formic acid, sodium dodecyl sulphate, etc.) have been used and their relative efficacy has been examined. Residual concentrations of the nanoparticles on various fabrics after 1, 3, 5 and 10 cycles of washing have been also studied. The treated fabrics keep their antibacterial properties after at least 3 times of laundering. The best finishing process to attach silver nanoparticles combination to various materials has been compared with biocidal properties of such antibacterial agents as metal salt solutions and zinc pyrithione.The possibility of treatment of nuclear track membranes by silver nanoparticles in order to prevent microbial growth on the surface of membranes has been discussed. (author)

Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

International Nuclear Information System (INIS)

Kemp, Melissa M; Linhardt, Robert J; Kumar, Ashavani; Ajayan, Pulickel; Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Mousa, Shaker A

2009-01-01

Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (P<0.01) as compared to glucose conjugation. These results suggest that DAPHP-reduced silver nanoparticles and gold nanoparticles have potential in pathological angiogenesis accelerated disorders such as cancer and inflammatory diseases.

Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

Energy Technology Data Exchange (ETDEWEB)

Kemp, Melissa M; Linhardt, Robert J [Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Kumar, Ashavani; Ajayan, Pulickel [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005 (United States); Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Mousa, Shaker A, E-mail: Shaker.mousa@acphs.ed [Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Albany, NY 12208 (United States)

2009-11-11

Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (P<0.01) as compared to glucose conjugation. These results suggest that DAPHP-reduced silver nanoparticles and gold nanoparticles have potential in pathological angiogenesis accelerated disorders such as cancer and inflammatory diseases.

Synthesis and characterization of monodispersed orthorhombic manganese oxide nanoparticles produced by Bacillus sp. cells simultaneous to its bioremediation

Energy Technology Data Exchange (ETDEWEB)

Sinha, Arvind [Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India); Singh, Vidya Nand; Mehta, Bodh Raj [Thin Film Laboratory, Department of Physics, Indian Institute of Technology, Delhi Hauz Khas, New Delhi 110016 (India); Khare, Sunil Kumar, E-mail: skhare@rocketmail.com [Enzyme and Microbial Biochemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India)

2011-08-30

Highlights: {yields} An efficient process wherein remediated manganese is synthesized into nanoparticles. {yields} A microbial process for manganese nanoparticle synthesis from metal waste streams. {yields} Nanoparticles characterized as monodispersed, spherical and 4.62 {+-} 0.14 nm sized MnO{sub 2}. -- Abstract: A heavy metal resistant strain of Bacillus sp. (MTCC10650) is reported. The strain exhibited the property of bioaccumulating manganese, simultaneous to its remediation. The nanoparticles thus formed were characterized and identified using energy dispersive X-ray analysis (EDAX), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD) and atomic force microscopy (AFM). When the cells were challenged with manganese, the cells effectively synthesized nanoparticles of average size 4.62 {+-} 0.14 nm. These were mostly spherical and monodispersed. The ex situ enzymatically synthesized nanoparticles exhibited an absorbance maximum at 329 nm. These were more discrete, small and uniform, than the manganese oxide nanoparticles recovered after cell sonication. The use of Bacillus sp. cells seems promising and advantageous approach. Since, it serves dual purposes of (i) remediation and (ii) nanoparticle synthesis. Considering the increasing demand of developing environmental friendly and cost effective technologies for nanoparticle synthesis, these cells can be exploited for the remediation of manganese from the environment in conjunction with development of a greener process for the controlled synthesis of manganese oxide nanoparticles.

Synthesis and characterization of monodispersed orthorhombic manganese oxide nanoparticles produced by Bacillus sp. cells simultaneous to its bioremediation

International Nuclear Information System (INIS)

Sinha, Arvind; Singh, Vidya Nand; Mehta, Bodh Raj; Khare, Sunil Kumar

2011-01-01

Highlights: → An efficient process wherein remediated manganese is synthesized into nanoparticles. → A microbial process for manganese nanoparticle synthesis from metal waste streams. → Nanoparticles characterized as monodispersed, spherical and 4.62 ± 0.14 nm sized MnO 2 . -- Abstract: A heavy metal resistant strain of Bacillus sp. (MTCC10650) is reported. The strain exhibited the property of bioaccumulating manganese, simultaneous to its remediation. The nanoparticles thus formed were characterized and identified using energy dispersive X-ray analysis (EDAX), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD) and atomic force microscopy (AFM). When the cells were challenged with manganese, the cells effectively synthesized nanoparticles of average size 4.62 ± 0.14 nm. These were mostly spherical and monodispersed. The ex situ enzymatically synthesized nanoparticles exhibited an absorbance maximum at 329 nm. These were more discrete, small and uniform, than the manganese oxide nanoparticles recovered after cell sonication. The use of Bacillus sp. cells seems promising and advantageous approach. Since, it serves dual purposes of (i) remediation and (ii) nanoparticle synthesis. Considering the increasing demand of developing environmental friendly and cost effective technologies for nanoparticle synthesis, these cells can be exploited for the remediation of manganese from the environment in conjunction with development of a greener process for the controlled synthesis of manganese oxide nanoparticles.

Fluorescent silver nanoparticles via exploding wire technique

Indian Academy of Sciences (India)

Pure silver nanoparticles in double distilled water were generated via simple physical method using pure (99.9%) silver wires with 0.2 mm diameter. These wires have been exploded in water by bringing them into sudden contact with pure (99.9%) silver plate when subjected to a potential difference of 36 V DC. High current.

Direct synthesis of silver nanoparticles in ionic liquid

International Nuclear Information System (INIS)

Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F.

2016-01-01

Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400–430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.Graphical Abstract

Direct synthesis of silver nanoparticles in ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F., E-mail: ffcamilo@unifesp.br [Universidade Federal de São Paulo, Laboratório de Materiais Híbridos, Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas (Brazil)

2016-05-15

Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400–430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.Graphical Abstract.

Effects of Prolonged Silver Nanoparticle Exposure on the Contextual Cognition and Behavior of Mammals

Directory of Open Access Journals (Sweden)

Anna Antsiferova

2018-04-01

Full Text Available Silver nanoparticles have been widely used in the lighting and food industries, in medicine, and in pharmaceutics as an antiseptic agent. Recent research demonstrates that, after prolonged oral administration, silver nanoparticles may cross the blood-brain barrier and accumulate in the brain in rather high amounts. In ex vivo experiments, it has also been shown that silver nanoparticles demonstrate neurotoxicity. The objective of this work was to answer the questions whether silver nanoparticles change cognitive and behavioral functions of mammals after prolonged administration if silver nanoparticles have accumulated in the brain. C57Bl/6 male mice were orally exposed to PVP-coated silver nanoparticles daily for 30, 60, 120 and 180 days. Control mice were exposed to distilled water. After that they were tested in the Open Field, Elevated Plus Maze, Light-Dark Box and contextual fear conditioning task. The data have shown that the experimental mice went through three periods of switching in the behavior caused by adaptation to the toxic silver nanoparticles: anxiety, appearance of research instinct and impairment of long-term memory. This provides evidence of the hazardous effect of silver nanoparticles, which appears after long periods of silver nanoparticle oral administration.

Silver Nanoparticles as Potential Antibacterial Agents

Directory of Open Access Journals (Sweden)

Gianluigi Franci

2015-05-01

Full Text Available Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials.

Silver nanoparticles as potential antibacterial agents.

Science.gov (United States)

Franci, Gianluigi; Falanga, Annarita; Galdiero, Stefania; Palomba, Luciana; Rai, Mahendra; Morelli, Giancarlo; Galdiero, Massimiliano

2015-05-18

Multi-drug resistance is a growing problem in the treatment of infectious diseases and the widespread use of broad-spectrum antibiotics has produced antibiotic resistance for many human bacterial pathogens. Advances in nanotechnology have opened new horizons in nanomedicine, allowing the synthesis of nanoparticles that can be assembled into complex architectures. Novel studies and technologies are devoted to understanding the mechanisms of disease for the design of new drugs, but unfortunately infectious diseases continue to be a major health burden worldwide. Since ancient times, silver was known for its anti-bacterial effects and for centuries it has been used for prevention and control of disparate infections. Currently nanotechnology and nanomaterials are fully integrated in common applications and objects that we use every day. In addition, the silver nanoparticles are attracting much interest because of their potent antibacterial activity. Many studies have also shown an important activity of silver nanoparticles against bacterial biofilms. This review aims to summarize the emerging efforts to address current challenges and solutions in the treatment of infectious diseases, particularly the use of nanosilver antimicrobials.

Effets of Silver Salt Concentrations on Green Synthesis of Silver Nanoparticles Using the Plant Nigella Saliva

Directory of Open Access Journals (Sweden)

M.R. Saeri

2016-03-01

Full Text Available Bio-inspired silver nanoparticles were synthesized with the aid of a novel method, using leaves of the plant Nigella sativa. After drying the leaves in air, they were first sweltered in boiling distilled water and the liquid was filtered subsequently. The result was the brothused to reduce solutions including various concentrations of silver nitrate in a proper amount of pH. The displayed UV–visible spectra identified formation of silver nanoparticles whenever the colorless initial acclimated mixture turned brown. The centrifuged powder samples were examined using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (FESEM and energy dispersive X-ray diffraction analysis (EDX methods. The results clearly revealed that the final particles of precipitated powder are high purity agglomerates of silver nanoparticles. Besides, the effects of various amounts of the silver salt on particle size of nano silver were studied, using a particle size analyzer. FTIR results also indicated the role of different functional groups in the synthetic process.

Improving the Vase life of Cut Carnation ‘Tempo’ (Dianthus carryophyllusL. Flower by Silver Thiosulphate and Silver Nano-Particles

Directory of Open Access Journals (Sweden)

D. Hashemabadi

2014-08-01

Full Text Available Nanometer-sized silver particle can be act as an anti-microbial compound. Thus, in this research, the efficacy of silver thiosulphate and silver nano-particles as antimicrobial agents in extending the vase-life of cut carnation flowers was evaluated. A factorial experiment carried out based on randomized completely blocks design with two factors: silver thiosulphate (0, 0.1, 0.2 and 0.3 mM and silver nano-particles (0, 5, 10 and 15 mg/L. Mean comparison of the data showed that the combined treatments of 0.3 mM silver thiosulphate + 15 mg/L silver nano-particles had the highest vase life, water uptake and super oxide dismutase enzyme. Thus, the mentioned above treatment was proposed to increase prolong vase life and improvement of water relations and control of stem end blockage. Based to results of this study, silver thiosulphate and silver nano-particles can be used for increasing postharvest longevity of cut carnation "Tempo".

Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent

Energy Technology Data Exchange (ETDEWEB)

Holtz, R D; Souza Filho, A G; Alves, O L [Laboratorio de Quimica do Estado Solido (LQES), Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13081-970, Campinas-SP (Brazil); Brocchi, M; Martins, D [Departamento de Genetica, Evolucao and Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Campinas-SP (Brazil); Duran, N, E-mail: rholtz@iqm.unicamp.br, E-mail: agsf@fisica.ufc.br, E-mail: oalves@iqm.unicamp.br [Laboratorio de Quimica Biologica, Instituto de Quimica, Universidade Estadual de Campinas, Campinas-SP (Brazil)

2010-05-07

In this work we report the synthesis, characterization and application of silver vanadate nanowires decorated with silver nanoparticles as a novel antibacterial agent. These hybrid materials were synthesized by a precipitation reaction of ammonium vanadate and silver nitrate followed by hydrothermal treatment. The silver vanadate nanowires have lengths of the order of microns and diameters around 60 nm. The silver nanoparticles decorating the nanowires present a diameter distribution varying from 1 to 20 nm. The influence of the pH of the reaction medium on the chemical structure and morphology of silver vanadates was studied and we found that synthesis performed at pH 5.5-6.0 led to silver vanadate nanowires with a higher morphological yield. The antimicrobial activity of these materials was evaluated against three strains of Staphylococcus aureus and very promising results were found. The minimum growth inhibiting concentration value against a MRSA strain was found to be ten folds lower than for the antibiotic oxacillin.

Uniform silver/polypyrrole core-shell nanoparticles synthesized by hydrothermal reaction

Energy Technology Data Exchange (ETDEWEB)

Wang Shibin [Department of Chemistry, Tsinghua University, Beijing 100084 (China); Shi Gaoquan [Department of Chemistry, Tsinghua University, Beijing 100084 (China)]. E-mail: gshi@tsinghua.edu.cn

2007-04-15

Uniformly sized silver/polypyrrole (Ag/PPy) core-shell nanoparticles were synthesized by one-step hydrothermal reaction of pyrrole and silver nitrate in the presence of polyvinyl pyrrolidone (PVP) as protection agent. The morphology and structures of the nanoparticles have been studied by scanning and transmission electronic microscopes, X-ray diffractometer and Raman spectroscopy. The experimental results indicated that the particles had 120 nm silver cores with 20 nm polypyrrole (PPy) coatings. The reaction conditions have strong effects on the morphology of the nanoparticles.

Uniform silver/polypyrrole core-shell nanoparticles synthesized by hydrothermal reaction

International Nuclear Information System (INIS)

Wang Shibin; Shi Gaoquan

2007-01-01

Uniformly sized silver/polypyrrole (Ag/PPy) core-shell nanoparticles were synthesized by one-step hydrothermal reaction of pyrrole and silver nitrate in the presence of polyvinyl pyrrolidone (PVP) as protection agent. The morphology and structures of the nanoparticles have been studied by scanning and transmission electronic microscopes, X-ray diffractometer and Raman spectroscopy. The experimental results indicated that the particles had 120 nm silver cores with 20 nm polypyrrole (PPy) coatings. The reaction conditions have strong effects on the morphology of the nanoparticles

Silver nanoparticles are broad-spectrum bactericidal and virucidal compounds

Directory of Open Access Journals (Sweden)

Ixtepan-Turrent Liliana

2011-08-01

Full Text Available Abstract The advance in nanotechnology has enabled us to utilize particles in the size of the nanoscale. This has created new therapeutic horizons, and in the case of silver, the currently available data only reveals the surface of the potential benefits and the wide range of applications. Interactions between viral biomolecules and silver nanoparticles suggest that the use of nanosystems may contribute importantly for the enhancement of current prevention of infection and antiviral therapies. Recently, it has been suggested that silver nanoparticles (AgNPs bind with external membrane of lipid enveloped virus to prevent the infection. Nevertheless, the interaction of AgNPs with viruses is a largely unexplored field. AgNPs has been studied particularly on HIV where it was demonstrated the mechanism of antiviral action of the nanoparticles as well as the inhibition the transmission of HIV-1 infection in human cervix organ culture. This review discusses recent advances in the understanding of the biocidal mechanisms of action of silver Nanoparticles.

Radiation Synthesis of PVA/ Chitosan Membranes Containing Silver Nanoparticles for Biomedical Applications

International Nuclear Information System (INIS)

Elbarbary, A.M.; El-Sawy, N.M.

2015-01-01

Silver Nanoparticles (AgNPs) were synthesized by γ-rays of polyvinyl alcohol/ chitosan (PVA/ CS) membranes containing silver nitrate (AgNO ) with promising antimicrobial and biomedical applications. The synthesized silver nanoparticles characterized by Ultra Violet spectroscopy (UV), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). UV studies showed a strong peak around λmax at 420 nm. A uniform distribution of silver nanoparticles inside PVA/ CS membranes was achieved by TEM investigation. The prepared silver nanoparticles showed good antimicrobial activity. The membranes containing AgNPs showed non-thrombogenicity effect and slightly haemolytic potential. The prepared membranes containing AgNPs had promising use in biomedical applications.

Non-monotonic wetting behavior of chitosan films induced by silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Praxedes, A.P.P.; Webler, G.D.; Souza, S.T. [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Ribeiro, A.S. [Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Fonseca, E.J.S. [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Oliveira, I.N. de, E-mail: italo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil)

2016-05-01

Highlights: • The addition of silver nanoparticles modifies the morphology of chitosan films. • Metallic nanoparticles can be used to control wetting properties of chitosan films. • The contact angle shows a non-monotonic dependence on the silver concentration. - Abstract: The present work is devoted to the study of structural and wetting properties of chitosan-based films containing silver nanoparticles. In particular, the effects of silver concentration on the morphology of chitosan films are characterized by different techniques, such as atomic force microscopy (AFM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). By means of dynamic contact angle measurements, we study the modification on surface properties of chitosan-based films due to the addition of silver nanoparticles. The results are analyzed in the light of molecular-kinetic theory which describes the wetting phenomena in terms of statistical dynamics for the displacement of liquid molecules in a solid substrate. Our results show that the wetting properties of chitosan-based films are high sensitive to the fraction of silver nanoparticles, with the equilibrium contact angle exhibiting a non-monotonic behavior.

A facile route to synthesize nanogels doped with silver nanoparticles

Science.gov (United States)

Coll Ferrer, M. Carme; Ferrier, Robert C.; Eckmann, David M.; Composto, Russell J.

2013-01-01

In this study, we describe a simple method to prepare hybrid nanogels consisting of a biocompatible core-shell polymer host containing silver nanoparticles. First, the nanogels (NG, 160 nm) containing a lysozyme rich core and a dextran rich shell, are prepared via Maillard and heat-gelation reactions. Second, silver nanoparticles (Ag NPs, 5 nm) are synthesized "in situ" in the NG solution without requiring additional reducing agents. This approach leads to stable Ag NPs located in the NG. Furthermore, we demonstrate that the amount of Ag NPs in the NG can be tuned by varying silver precursor concentration. Hybrid nanogels with silver nanoparticles have potential in antimicrobial, optical, and therapeutic applications.

Green synthesis of silver nanoparticles and biopolymer ...

Indian Academy of Sciences (India)

2018-03-29

Mar 29, 2018 ... Keywords. Biogenic silver nanoparticles; biopolymer nanocomposites; nanoparticles stability; ... Production of nanomaterials by using living organisms of plant-based ... 2.1b Microorganisms and cell culture: The evaluation of.

Synthesis, characterization and catalytic activity of silver nanoparticles using Tribulus terrestris leaf extract.

Science.gov (United States)

Ashokkumar, S; Ravi, S; Kathiravan, V; Velmurugan, S

2014-01-01

Biomediated silver nanoparticles were synthesized with the aid of an eco-friendly biomaterial, namely, aqueous Tribulus terrestris extract. Silver nanoparticles were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous T. terrestris leaf extracts as both the reducing and capping agent. Silver ions were rapidly reduced by aqueous T. terrestris leaf extracts, leading to the formation of highly crystalline silver nanoparticles. An attempt has been made and formation of the silver nanoparticles was verified by surface plasmon spectra using an UV-vis (Ultra violet), spectrophotometer. Morphology and crystalline structure of the prepared silver nanoparticles were characterized by TEM (Transmission Electron Microscope) and XRD (X-ray Diffraction), techniques, respectively. FT-IR (Fourier Transform Infrared), analysis suggests that the obtained silver nanoparticles might be stabilized through the interactions of carboxylic groups, carbonyl groups and the flavonoids present in the T. terrestris extract. Copyright © 2013 Elsevier B.V. All rights reserved.

Antimicrobial Activities of Silver Nanoparticles Synthesized by Using Water Extract of Arnicae anthodium.

Science.gov (United States)

Dobrucka, Renata; Długaszewska, Jolanta

2015-06-01

Green synthesis of nanoparticles has gained significant importance in recent years and has become the one of the most preferred methods. Also, green synthesis of nanoparticles is valuable branch of nanotechnology. Plant extracts are eco-friendly and can be an economic option for synthesis of nanoparticles. This study presents method the synthesis of silver nanoparticles using water extract of Arnicae anthodium. Formation of silver nanoparticles was confirmed by UV-visble spectroscopy, Fourier transform infrared spectroscopy and total reflection X-ray fluorescence analysis. The morphology of the synthesized silver nanoparticles was verified by SEM-EDS. The obtained silver nanoparticles were used to study their antimicrobial activity.

Biological evaluation of silver nanoparticles incorporated into chitosan-based membranes

NARCIS (Netherlands)

Shao, J.; Yu, N.; Kolwijck, E.; Wang, B.; Tan, K.W.; Jansen, J.A.; Walboomers, X.F.; Yang, F.

2017-01-01

AIM: To evaluate the antibacterial potential and biological performance of silver nanoparticles in chitosan-based membranes. MATERIALS & METHODS: Electrospun chitosan/poly(ethylene oxide) membranes with different amounts of silver nanoparticles were evaluated for antibacterial properties and

Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

Science.gov (United States)

Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

2014-02-01

The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. © 2013.

Characterization and Biocompatibility of Chitosan Gels with Silver and Gold Nanoparticles

Directory of Open Access Journals (Sweden)

C. Sámano-Valencia

2014-01-01

Full Text Available The presence of bacterial resistance to antibiotics is a very important issue and the search of new alternatives is necessary. In this work, a combination of chitosan gel with silver or gold nanoparticles was prepared and characterized using thermal, rheology, bactericide, and biocompatibility analyses. ESEM images were also taken to visualize the incorporation of the nanoparticles into the gel matrix. Thermal analysis showed a better thermal stability in the chitosan-gold nanoparticles gels compared to the chitosan-silver nanoparticles gels. Rheology analyses showed that the viscosity of the gels decreased when velocity increased and there were differences in viscosity when silver and gold nanoparticles concentrations change. ESEM images showed the presence of agglomerates of silver and gold nanoparticles into the gel matrix with a good distribution; in some cases the formation of microstructures was found. Bactericide results show that these materials present an antibacterial activity against S. aureus, S. mutans, and E. coli. The biocompatibility test showed neither negative reaction nor wound healing delay after the application of the gels in an in vivo test. The gels with silver and gold nanoparticles could be used to treat wound infections in oral or skin applications.

Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects

Science.gov (United States)

Prabhu, Sukumaran; Poulose, Eldho K.

2012-10-01

Silver nanoparticles are nanoparticles of silver which are in the range of 1 and 100 nm in size. Silver nanoparticles have unique properties which help in molecular diagnostics, in therapies, as well as in devices that are used in several medical procedures. The major methods used for silver nanoparticle synthesis are the physical and chemical methods. The problem with the chemical and physical methods is that the synthesis is expensive and can also have toxic substances absorbed onto them. To overcome this, the biological method provides a feasible alternative. The major biological systems involved in this are bacteria, fungi, and plant extracts. The major applications of silver nanoparticles in the medical field include diagnostic applications and therapeutic applications. In most of the therapeutic applications, it is the antimicrobial property that is being majorly explored, though the anti-inflammatory property has its fair share of applications. Though silver nanoparticles are rampantly used in many medical procedures and devices as well as in various biological fields, they have their drawbacks due to nanotoxicity. This review provides a comprehensive view on the mechanism of action, production, applications in the medical field, and the health and environmental concerns that are allegedly caused due to these nanoparticles. The focus is on effective and efficient synthesis of silver nanoparticles while exploring their various prospective applications besides trying to understand the current scenario in the debates on the toxicity concerns these nanoparticles pose.

Photocatalytic activity of biogenic silver nanoparticles synthesized using potato (Solanum tuberosum) infusion.

Science.gov (United States)

Roy, Kaushik; Sarkar, C K; Ghosh, C K

2015-07-05

In this study, we have reported a fast and eco-benign procedure to synthesis silver nanoparticle at room temperature using potato (Solanum tuberosum) infusion along with the study of its photocatalytic activity on methyl orange dye. After addition of potato infusion to silver nitrate solution, the color of the mixture changed indicating formation of silver nanoparticles. Time dependent UV-Vis spectra were obtained to study the rate of nanoparticle formation with time. Purity and crystallinity of the biogenic silver nanoparticles were examined by X-ray diffraction (XRD). Average size and morphology of the nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Fourier transform infra-red spectroscopy (FTIR) was employed to detect functional bio-molecules responsible that contribute to the reduction and capping of biosynthesized Ag nanoparticles. Further, these synthesized nanoparticles were used to investigate their ability to degrade methyl orange dye under sunlight irradiation and the results showed effective photocatalytic property of these biogenic silver nanoparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis of Monodispersed Gold Nanoparticles with Exceptional Colloidal Stability with Grafted Polyethylene Glycol-g-polyvinyl Alcohol

Directory of Open Access Journals (Sweden)

Alaaldin M. Alkilany

2015-01-01

Full Text Available Herein, we report the synthesis of spherical gold nanoparticles with tunable core size (23–79 nm in the presence of polyethylene glycol-g-polyvinyl alcohol (PEG-g-PVA grafted copolymer as a reducing, capping, and stabilizing agent in a one-step protocol. The resulted PEG-g-PVA-capped gold nanoparticles are monodispersed with an exceptional colloidal stability against salt addition, repeated centrifugation, and extensive dialysis. The effect of various synthesis parameters and the kinetic/mechanism of the nanoparticle formation are discussed.

Silver nanoparticles – a material of the future…?

Directory of Open Access Journals (Sweden)

Pulit-Prociak Jolanta

2016-01-01

Full Text Available The paper presents properties of nanomaterials and methods of their principal applications. Environmental aspects of using nanomaterials and reasons for their toxicity are also reviewed. The vast part of the paper is devoted to properties, application and market of silver nanoparticles. Their biocidal activity is clarified. However, silver nanoparticles may cause environmental pollution. Reasons for their toxicity have been also described.

Kinetic formation of silver-copper nanoparticles and its characterization

Science.gov (United States)

Zulkafi, Nurul Hikmah; Idrus, Nor Faeqah; Jai, Junaidah; Hadi, Abdul

2017-12-01

A study of the kinetic formation of silver-copper nanoparticles in aqueous medium on the basis of size distribution and its characterization has been carried out and reported in this paper. The Ag-Cu nanoparticles were synthesized through polyol method that using Ethylene Glycol (H2C6O12) as a reduction agent and solvent and Polyoxyethylene-(80)-Sorbitan Monooleate (Tween 80) as a stabilizer. The kinetic formation of Ag-Cu nanoparticles was observed using Dynamic Light Scattering (DLS) and characterized by using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (TEM). The XRD analysis results confirmed that size distribution was strongly dependent on molarity of precursors of silver (AgNO3) and copper (Cu(NO3)2.3H2O). The FESEM and TEM analysis indicated the existence of Ag and Cu nanoparticles in the core-shell shape. The silver-copper nanoparticles were spherical and uniform particles size with the average size of about 28 nm and 38 nm for silver and copper, respectively. DLS observation showed the growth of nanoparticles at the temperature of 140°C as the effect of reaction time at 1, 2, 3, 4 and 5 hours.

Magnetite and magnetite/silver core/shell nanoparticles with diluted magnet-like behavior

International Nuclear Information System (INIS)

Garza-Navarro, Marco; Torres-Castro, Alejandro; Gonzalez, Virgilio; Ortiz, Ubaldo; De la Rosa, Elder

2010-01-01

In the present work is reported the use of the biopolymer chitosan as template for the preparation of magnetite and magnetite/silver core/shell nanoparticles systems, following a two step procedure of magnetite nanoparticles in situ precipitation and subsequent silver ions reduction. The crystalline and morphological characteristics of both magnetite and magnetite/silver core/shell nanoparticles systems were analyzed by high resolution transmission electron microscopy (HRTEM) and nanobeam diffraction patterns (NBD). The results of these studies corroborate the core/shell morphology and the crystalline structure of the magnetite core and the silver shell. Moreover, magnetization temperature dependent, M(T), measurements show an unusual diluted magnetic behavior attributed to the dilution of the magnetic ordering in the magnetite and magnetite/silver core/shell nanoparticles systems. - Graphical abstract: Biopolymer chitosan was used as stabilization media to synthesize both magnetite and magnetite/silver core/shell nanoparticles. Results of HRTEM and NBD patterns confirm core/shell morphology of the obtained nanoparticles. It was found that the composites show diluted magnet-like behavior.

Characterization of silver nanoparticles synthesized using an endophytic fungus, Penicillium oxalicum having potential antimicrobial activity

Science.gov (United States)

Bhattacharjee, Sukla; Debnath, Gopal; Das, Aparajita Roy; Krishna Saha, Ajay; Das, Panna

2017-12-01

The aim of the present study was to test the efficacy of the extracellular mycelium extract of Penicillium oxalicum isolated from Phlogacanthus thyrsiflorus to biosynthesize silver nanoparticles. It was characterized using ultraviolet-visible absorption spectroscopy, atomic force microscopy, transmission electron microscopy and Fourier transforms infrared spectroscopy. The silver nanoparticles were evaluated for antimicrobial activity. The characterization confirms the synthesis of silver nanoparticles. Both silver nanoparticles and combination of silver nanoparticles with streptomycin showed activity against the four bacteria. The results suggested that P. oxalicum offers eco-friendly production of silver nanoparticles and the antibacterial activity may find application in biomedicine.

A facile route to synthesize nanogels doped with silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Coll Ferrer, M. Carme [University of Pennsylvania, Department of Materials Science (United States); Ferrier, Robert C. [University of Pennsylvania, Department of Chemical and Biomolecular Engineering (United States); Eckmann, David M. [University of Pennsylvania, Department of Anesthesiology and Critical Care (United States); Composto, Russell J., E-mail: composto@seas.upenn.edu [University of Pennsylvania, Department of Materials Science (United States)

2013-01-15

In this study, we describe a simple method to prepare hybrid nanogels consisting of a biocompatible core-shell polymer host containing silver nanoparticles. First, the nanogels (NG, {approx}160 nm) containing a lysozyme rich core and a dextran rich shell, are prepared via Maillard and heat-gelation reactions. Second, silver nanoparticles (Ag NPs, {approx}5 nm) are synthesized 'in situ' in the NG solution without requiring additional reducing agents. This approach leads to stable Ag NPs located in the NG. Furthermore, we demonstrate that the amount of Ag NPs in the NG can be tuned by varying silver precursor concentration. Hybrid nanogels with silver nanoparticles have potential in antimicrobial, optical, and therapeutic applications.

A facile route to synthesize nanogels doped with silver nanoparticles

International Nuclear Information System (INIS)

Coll Ferrer, M. Carme; Ferrier, Robert C.; Eckmann, David M.; Composto, Russell J.

2013-01-01

In this study, we describe a simple method to prepare hybrid nanogels consisting of a biocompatible core–shell polymer host containing silver nanoparticles. First, the nanogels (NG, ∼160 nm) containing a lysozyme rich core and a dextran rich shell, are prepared via Maillard and heat-gelation reactions. Second, silver nanoparticles (Ag NPs, ∼5 nm) are synthesized “in situ” in the NG solution without requiring additional reducing agents. This approach leads to stable Ag NPs located in the NG. Furthermore, we demonstrate that the amount of Ag NPs in the NG can be tuned by varying silver precursor concentration. Hybrid nanogels with silver nanoparticles have potential in antimicrobial, optical, and therapeutic applications.

Shell crosslinked nanoparticles carrying silver antimicrobials as therapeutics†

Science.gov (United States)

Li, Yali; Hindi, Khadijah; Watts, Kristin M.; Taylor, Jane B.; Zhang, Ke; Li, Zicheng

2010-01-01

Amphiphilic polymer nanoparticles loaded with silver cations or/and N-heterocyclic carbene–silver complexes were assessed as antimicrobial agents against Gram-negative pathogens Escherichia coli and Pseudomonas aeruginosa. PMID:20024313

Rapid Synthesis of Silver Nanoparticles from Fusarium oxysporum by Optimizing Physicocultural Conditions

Directory of Open Access Journals (Sweden)

Sonal S. Birla

2013-01-01

Full Text Available Synthesis of silver nanoparticles (SNPs by fungi is emerging as an important branch of nanotechnology due to its ecofriendly, safe, and cost-effective nature. In order to increase the yield of biosynthesized SNPs of desired shape and size, it is necessary to control the cultural and physical parameters during the synthesis. We report optimum synthesis of SNPs on malt extract glucose yeast extract peptone (MGYP medium at pH 9–11, 40–60°C, and 190.7 Lux and in sun light. The salt concentrations, volume of filtrate and biomass quantity were found to be directly proportional to the yield. The optimized conditions for the stable and rapid synthesis will help in large scale synthesis of monodispersed SNPs. The main aim of the present study was to optimize different media, temperature, pH, light intensity, salt concentration, volume of filtrate, and biomass quantity for the synthesis of SNPs by Fusarium oxysporum.

Low molecular weight compounds as effective dispersing agents in the formation of colloidal silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Natsuki, Jun; Natsuki, Toshiaki, E-mail: natsuki@shinshu-u.ac.jp; Abe, Takao [Shinshu University, Faculty of Textile Science and Technology (Japan)

2013-03-15

A convenient method to synthesize uniform, well-dispersed colloidal silver nanoparticles is described. Aldonic acid or {alpha}-hydroxy acid compounds of low molecular weight are used instead of polymeric compounds as dispersing agents to prepare silver nanoparticles. The size, conformation, and electrical conductivity of the silver nanoparticles, and the effect and function of the dispersing agents are investigated in detail. Using these low molecular weight compounds as dispersing agents, silver nanoparticles with a diameter of 10 nm or less and high electrical conductivity can be obtained. In addition, this procedure allows silver nanoparticles to be sintered at 150 Degree-Sign C, which is lower than that required for silver nanoparticle formulation using polymeric compounds (200 Degree-Sign C). The silver nanoparticles produced by this process can be used to prepare various inks and to manufacture electronic circuits. It is found that low molecular weight compounds are more effective dispersing agents than polymeric compounds in the formation of silver nanoparticles.

Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

Science.gov (United States)

Kemp, Melissa M.; Kumar, Ashavani; Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Ajayan, Pulickel; Linhardt, Robert J.; Mousa, Shaker A.

2009-11-01

Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (Pcancer and inflammatory diseases.

Silver nanoparticles delivery system based on natural rubber latex membranes

Energy Technology Data Exchange (ETDEWEB)

Guidelli, Eder Jose, E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo/FFCLRP-DF (Brazil); Kinoshita, Angela [Universidade do Sagrado Coracao (Brazil); Ramos, Ana Paula [Universidade de Sao Paulo/FFCLRP-DQ (Brazil); Baffa, Oswaldo [Universidade de Sao Paulo/FFCLRP-DF (Brazil)

2013-04-15

The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV-Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane ({approx}0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are

Silver nanoparticles delivery system based on natural rubber latex membranes

International Nuclear Information System (INIS)

Guidelli, Éder José; Kinoshita, Angela; Ramos, Ana Paula; Baffa, Oswaldo

2013-01-01

The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV–Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane (∼0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are sterically

Laser-fabricated castor oil-capped silver nanoparticles.

Science.gov (United States)

Zamiri, Reza; Zakaria, Azmi; Abbastabar, Hossein; Darroudi, Majid; Husin, Mohd Shahril; Mahdi, Mohd Adzir

2011-01-01

Silver nanoparticles were fabricated by ablation of a pure silver plate immersed in castor oil. A Nd:YAG-pulsed Q-switch laser with 1064-nm wavelength and 10-Hz frequency was used to ablate the plate for 10 minutes. The sample was characterized by ultraviolet-visible, atomic absorption, Fourier transform-infrared spectroscopies, and transmission electron microscopy. The results of the fabricated sample showed that the nanoparticles in castor oil were about 5-nm in diameter, well dispersed, and showed stability for a long period of time.

Nanosecond (ns) laser transfer of silver nanoparticles from silver-exchanged soda-lime glass to transparent soda-lime glass and shock waves formation

International Nuclear Information System (INIS)

Sow, Mohamed Chérif; Blondeau, Jean-Philippe; Sagot, Nadine; Ollier, Nadège; Tite, Teddy

2015-01-01

Highlights: • Silver nanoparticles growth by nanosecond laser irradiation of silver exchanged soda-lime glasses. • Silver nanoparticles transfer. • Nanosecond laser induced shock waves formation on glass. - Abstract: In this contribution, we showed for the first time in our knowledge a single-step process for silver clusters and nanoparticles growth and transfer from silver-exchanged soda-lime glass to un-exchanged soda-lime glass (transparent glass in visible and NIR domain) by nanosecond (ns) laser irradiation. The transferred silver nanoparticles in transparent glass are strongly linked to the glass surface. In addition, we point out the formation of shock waves, with selective silver clustering on the top wave. This technique provides an alternative and simple way to obtain metallic nanoparticles in different media which can be traversed by laser wavelength used. Moreover, this experiment is made at room temperature and air environment. It is worth noting that our technique requires a glass previously doped with the corresponding silver ions

Structural characterization and antimicrobial properties of silver nanoparticles prepared by inverse microemulsion method.

Science.gov (United States)

Wani, Irshad A; Khatoon, Sarvari; Ganguly, Aparna; Ahmed, Jahangeer; Ahmad, Tokeer; Manzoor, Nikhat

2013-01-01

Silver nanoparticles have been synthesized in the inverse microemulsions formed using three different surfactants viz., cetyl-trimethyl ammonium bromide (CTAB), Tergitol and Triton X-100. We have done a systematic study of the effect of the surfactants on the particle size and properties of the silver nanoparticles. Microscopic studies show the formation of spheres, cubes and discs shaped silver nanostructures with the size in the range from 8 to 40 nm. Surface plasmon resonance (SPR) peak was observed around 400 nm and 500 nm. In addition to SPR some extra peaks have also been observed due to the formation of silver metal clusters. The surface area increases from 3.45 to 15.06 m(2)/g with decreasing the size of silver nanoparticles (40-8 nm). To investigate the antimicrobial activity of silver nanoparticles, the nanoparticles were tested against the yeast, Candida albicans and the bacterium, E. coli. The results suggest very good antimicrobial activity of the silver nanoparticles against the test microbes. The mode of action of the antimicrobial activity was also proposed. Copyright © 2012 Elsevier B.V. All rights reserved.

Biosynthesis of silver and gold nanoparticles by novel sundried Cinnamomum camphora leaf

International Nuclear Information System (INIS)

Huang Jiale; Li Qingbiao; Sun Daohua; Lu Yinghua; Su Yuanbo; Yang Xin; Wang Huixuan; Wang Yuanpeng; Shao Wenyao; He Ning; Hong Jinqing; Chen Cuixue

2007-01-01

The synthesis of nanocrystals is in the limelight in modern nanotechnology. Biosynthesis of nanoparticles by plant extracts is currently under exploitation. Not only could silver nanoparticles ranging from 55 to 80 nm in size be fabricated, but also triangular or spherical shaped gold nanoparticles could be easily modulated by reacting the novel sundried biomass of Cinnamomum camphora leaf with aqueous silver or gold precursors at ambient temperature. The marked difference of shape control between gold and silver nanoparticles was attributed to the comparative advantage of protective biomolecules and reductive biomolecules. The polyol components and the water-soluble heterocyclic components were mainly responsible for the reduction of silver ions or chloroaurate ions and the stabilization of the nanoparticles, respectively. The sundried leaf in this work was very suitable for simple synthesis of nanoparticles

Excellent electrochemical performance of graphene-silver nanoparticle hybrids prepared using a microwave spark assistance process

International Nuclear Information System (INIS)

Shanmugharaj, A.M.; Ryu, Sung Hun

2012-01-01

Highlights: ► A simple synthesis route is explored in preparing graphene-metal nanoparticle hybrids using cost effective microwave radiation process. ► Electrochemical performance of the synthesized graphene-silver nanoparticle hybrids have been compared with graphite and silver nanoparticle based anode materials. ► Graphene-silver nanoparticle hybrid exhibits stable charge/discharge characteristics of 714 mAh g −1 and it is significantly higher compared to natural graphite and silver based electrodes. - Abstract: A simple method is described for the synthesis of graphene-silver nanoparticle hybrids from graphite and silver precursors using microwave spark ignition process. Adding ecofriendly free radical initiators, in the presence of hydrogen peroxide solution leads to the expansion of graphite to graphene nanosheets. Simultaneously, silver ions intercalated between the graphene layers are reduced to silver nanocrystals leading to the development of graphene-silver nanoparticle hybrids. Transmission electron microscopic (TEM) studies reveal the successful formation of graphene-silver nanoparticle hybrids. X-ray diffraction (XRD) shows that the silver nanoparticles formed on the graphene surfaces are face centered cubic crystals. The surface composition and functional groups present on the graphene-silver nanoparticle hybrids are corroborated using X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FT-IR). The lithium storage capacity of the synthesized material, when used as an anode material for rechargeable lithium secondary batteries is investigated. Its first specific discharge capacity is observed to be 580 mAh g −1 and this has been increased to 827 mAh g −1 , by incorporating the silver nanoparticles between the graphene platelets. The reversible capacity of the graphene-silver nanoparticle hybrids is observed to be 714 mAh g −1 , which is significantly higher compared to that of graphene (420 mAh g −1

[Antimicrobial activity of stable silver nanoparticles of a certain size].

Science.gov (United States)

Mukha, Iu P; Eremenko, A M; Smirnova, N P; Mikhienkova, A I; Korchak, G I; Gorchev, V F; Chunikhin, A Iu

2013-01-01

Conditions for obtaining stable silver nanoparticles smaller than 10 nm were developed using a binary stabilizer polyvinylpyrrolidone/sodium dodecylsulphate in optimal ratio. Optical spectra, morphology and dependence of size of the nanoparticles on the amount of reducing agent were studied. Colloidal solutions of nanosilver showed a high bactericidal activity against strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and fungicidal activity against Candida albicans. The mechanism of action of nanosized silver on microbial cell was examined by laser scanning confocal microscope using fluorescent label. First step of antimicrobial effect on microorganisms was membrane damage and penetration of silver nanoparticles into the cell. Prolonged stability of nanoparticles and their antimicrobial activity over the past two years were showed.

Silver nanoparticles: synthesis and size control by electron irradiation

Energy Technology Data Exchange (ETDEWEB)

Bogle, K A; Dhole, S D; Bhoraskar, V N [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune-411007 (India)

2006-07-14

Silver nanoparticles were synthesized by irradiating solutions, prepared by mixing AgNO{sub 3} and poly-vinyl alcohol (PVA), with 6 MeV electrons. The electron-irradiated solutions and the thin coatings cast from them were characterized using the ultraviolet-visible (UV-vis), x-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. During electron irradiation, the process of formation of the silver nanoparticles appeared to be initiated at an electron fluence of {approx}2 x 10{sup 13} e cm{sup -2}. This was evidenced from the solution, which turned yellow and exhibited the characteristic plasmon absorption peak around 455 nm. Silver nanoparticles of different sizes in the range 60-10 nm, with a narrow size distribution, could be synthesized by varying the electron fluence from 2 x 10{sup 13} to 3 x 10{sup 15} e cm{sup -2}. Silver nanoparticles of sizes in the range 100-200 nm were also synthesized by irradiating an aqueous AgNO{sub 3} solution with 6 MeV electrons.

Green Synthesis of Silver Nanoparticles and the Study of Optical Properties

OpenAIRE

Vasireddy, Ramakrishna; Paul, Rima; Mitra, Apurba Krishna

2012-01-01

The synthesis of silver nanoparticles of varying size has been achieved using different molar concentrations of NaOH while the effect of changing the temperature has been studied. AgNO3, gelatine, glucose and NaOH are used as a silver precursor, stabilizer, reducing agent and accelerator respectively. The synthesized nanoparticles have been characterized by a FESEM study, X‐ray diffractometry, Raman spectroscopy and UV‐vis spectroscopy. The colloidal sols of the silver nanoparticles in a biop...

Organometallic approach to polymer-protected antibacterial silver nanoparticles: optimal nanoparticle size-selection for bacteria interaction

Energy Technology Data Exchange (ETDEWEB)

Crespo, Julian; Garcia-Barrasa, Jorge; Lopez-de-Luzuriaga, Jose M.; Monge, Miguel, E-mail: miguel.monge@unirioja.es; Olmos, M. Elena [Universidad de La Rioja, Centro de Investigacion en Sintesis Quimica (CISQ), Departamento de Quimica (Spain); Saenz, Yolanda; Torres, Carmen [Centro de Investigacion Biomedica de La Rioja, Area de Microbiologia Molecular (Spain)

2012-12-15

The optimal size-specific affinity of silver nanoparticles (Ag NPs) towards E. coli bacteria has been studied. For this purpose, Ag NPs coated with polyvinylpyrrolidone (PVP) and cellulose acetate (CA) have been prepared using an organometallic approach. The complex NBu{sub 4}[Ag(C{sub 6}F{sub 5}){sub 2}] has been treated with AgClO{sub 4} in a 1:1 molar ratio giving rise to the nanoparticle precursor [Ag(C{sub 6}F{sub 5})] in solution. Addition of an excess of PVP (1) or CA (2) and 5 h of reflux in tetrahydrofuran (THF) at 66 Degree-Sign C leads to Ag NPs of small size (4.8 {+-} 3.0 nm for PVP-Ag NPs and 3.0 {+-} 1.2 nm for CA-Ag NPs) that coexist in both cases with larger nanoparticles between 7 and 25 nm. Both nanomaterials display a high antibacterial effectiveness against E. coli. The TEM analysis of the nanoparticle-bacterial cell membrane interaction shows an optimal size-specific affinity for PVP-Ag NPs of 5.4 {+-} 0.7 nm in the presence of larger size silver nanoparticles.Graphical AbstractAn organometallic approach permits the synthesis of small size silver nanoparticles (ca 5 nm) as a main population in the presence of larger size nanoparticles. Optimal silver nanoparticle size-selection (5.4 nm) for the interaction with the bacterial membrane is achieved.

Green Synthesis of Silver Nanoparticles from several NTFP Plants

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Somnath BHOWMIK

2016-03-01

Full Text Available The biological synthesis of nanoparticles using plant extracts plays an important role in the field of nanotechnology. In this study, rapid, simple approach was applied for synthesis of silver nanoparticles using , Clerodendrum infortunatum, Mucuna interrupta, Phlogancanthus thyrsiflorus and Sansevieria trifasciata aqueous leaf extract. The plant extract acts both as reducing agent as well as capping agent. To identify the compounds responsible for reduction of silver ions, the functional groups present in plant extract were investigated by FTIR. Various techniques used to characterize synthesized nanoparticles are Scanning Electron Microscopy (SEM, Atomic Force Microscopy (AFM and UV–Visible spectrophotometer. Results confirmed that this protocol was simple, rapid, one step, eco-friendly, non-toxic and might be an alternative conventional physical/chemical methods. Conversion of silver nanoparticles takes place at room temperature without the involvement of any hazardous chemicals.

Characterization and antimicrobial activity of silver nanoparticles, biosynthesized using Bacillus species

Science.gov (United States)

Ghiuță, I.; Cristea, D.; Croitoru, C.; Kost, J.; Wenkert, R.; Vyrides, I.; Anayiotos, A.; Munteanu, D.

2018-04-01

In this work, the biosynthesis of silver nanoparticles, using AgNO3 as a precursor, by two Bacillus species, namely Bacillus amyloliquefaciens and Bacillus subtillis, is reported. After the synthesis stages, the absorbance of the brown nanoparticle colloidal solutions was assessed by UV-vis spectrophotometry, which showed the peak absorbance values at 418 nm and 414 nm, corresponding to surface plasmon resonance of silver nanoparticles. The EDX, SEM and DLS analyses confirmed the formation of spherical silver nanoparticles with an average diameter smaller than 140 nm. XRD confirmed the presence of face-centered cubic silver crystals, with the highest intensity peak at 2θ = 38.12°, which corresponds to the (111) diffraction planes. The antibacterial activity after 24 h of incubation was observed against gram negative bacteria: Escherichia coli, Pseudomonas aeruginosa, Salmonella, as well as gram positive: Staphylococcus aureus, Streptococcus pyogenes. Furthermore, the antifungal activity was assessed against Candida albicans. The inhibition zone was clearly observed on the plates containing silver nanoparticles, either standalone or in combination with antibiotics, thus showing their potentiating antibacterial effect.

Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process

International Nuclear Information System (INIS)

Duran, Nelson; Marcato, Priscyla D.; Alves, Oswaldo L.; Silva, Joao P. S. Da; Souza, Gabriel I. H. De; Rodrigues, Flavio A.; Esposito, Elisa

2010-01-01

This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

Ecosystem protection by effluent bioremediation: silver nanoparticles impregnation in a textile fabrics process

Energy Technology Data Exchange (ETDEWEB)

Duran, Nelson, E-mail: duran@iqm.unicamp.br; Marcato, Priscyla D. [Universidade Estadual de Campinas, Biological Chemistry Laboratory, Instituto de Quimica (Brazil); Alves, Oswaldo L. [Universidade Estadual de Campinas, Solid State Chemistry Laboratory, Instituto de Quimica (Brazil); Silva, Joao P. S. Da; Souza, Gabriel I. H. De [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil); Rodrigues, Flavio A. [Universidade de Mogi das Cruzes, Material Chemistry Laboratory, Biochemical Research Center (Brazil); Esposito, Elisa [Universidade de Mogi das Cruzes, Biological Chemistry and Biotechnology Laboratory, Environmental Sciences Center (Brazil)

2010-01-15

This work studied a bioremediation process of silver nanoparticles with the bacterium Chromobacterium violaceum. These nanoparticles were obtained from several washes of cotton fabrics impregnated with silver nanoparticles produced by the fungus Fusarium oxysporum. The optimized growth of C. violaceum for silver nanoparticles bioremediation was obtained. The effluents of wash process of the cotton fabric were efficiently treated with C. violaceum. This treatment was based on biosorption which was very efficient for the elimination of silver nanoparticles remaining in the wash water. The bacteria after biosorption were morphologically transformed, but the normal morphology after a new culture was completely restored. The process also allowed the recovery of silver material that was leached into the effluent for a reutilization avoiding any effect to the eco-environment.

Green biosynthesis of silver nanoparticles using Curcuma longa tuber powder

Science.gov (United States)

Shameli, Kamyar; Ahmad, Mansor Bin; Zamanian, Ali; Sangpour, Parvanh; Shabanzadeh, Parvaneh; Abdollahi, Yadollah; Zargar, Mohsen

2012-01-01

Green synthesis of noble metal nanoparticles is a vastly developing area of research. Metallic nanoparticles have received great attention from chemists, physicists, biologists, and engineers who wish to use them for the development of a new-generation of nanodevices. In this study, silver nanoparticles were biosynthesized from aqueous silver nitrate through a simple and eco-friendly route using Curcuma longa tuber-powder extracts, which acted as a reductant and stabilizer simultaneously. Characterizations of nanoparticles were done using different methods, which included ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier-transform infrared spectroscopy. The ultraviolet-visible spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 415 nm. Transmission electron microscopy showed that mean diameter and standard deviation for the formation of silver nanoparticles was 6.30 ± 2.64 nm. Powder X-ray diffraction showed that the particles are crystalline in nature, with a face-centered cubic structure. The most needed outcome of this work will be the development of value-added products from C. longa for biomedical and nanotechnology-based industries. PMID:23341739

[Ag25(SR)18]¯: The ‘Golden’ Silver Nanoparticle

KAUST Repository

Joshi, Chakra Prasad

2015-08-31

Silver nanoparticles with an atomically precise molecular formula [Ag25(SR)18]¯ (‒SR: thiolate) are synthesized and their single-crystal structure is determined. This synthesized nanocluster is the only silver nanoparticle that has a virtually identical analogue in gold, i.e., [Au25(SR)18]¯, in terms of number of metal atoms, ligand count, super-atom electronic configuration, and atomic arrangement. Furthermore, both [Ag25(SR)18]¯ and its gold analogue share a number of features in their optical absorption spectra. This unprecedented molecular synthesis in silver to mimic gold offers the first model nanoparticle platform to investigate the centuries-old problem of understanding the fundamental differences between silver and gold in terms of nobility, catalytic activity, and optical property.

[Ag25(SR)18]¯: The ‘Golden’ Silver Nanoparticle

KAUST Repository

Joshi, Chakra Prasad; Bootharaju, Megalamane Siddaramappa; Alhilaly, Mohammad J.; Bakr, Osman

2015-01-01

Silver nanoparticles with an atomically precise molecular formula [Ag25(SR)18]¯ (‒SR: thiolate) are synthesized and their single-crystal structure is determined. This synthesized nanocluster is the only silver nanoparticle that has a virtually identical analogue in gold, i.e., [Au25(SR)18]¯, in terms of number of metal atoms, ligand count, super-atom electronic configuration, and atomic arrangement. Furthermore, both [Ag25(SR)18]¯ and its gold analogue share a number of features in their optical absorption spectra. This unprecedented molecular synthesis in silver to mimic gold offers the first model nanoparticle platform to investigate the centuries-old problem of understanding the fundamental differences between silver and gold in terms of nobility, catalytic activity, and optical property.

Preparation of Crosslinked Amphiphilic Silver Nanogel as Thin Film Corrosion Protective Layer for Steel

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Ayman M. Atta

2014-07-01

Full Text Available Monodisperse silver nanoparticles were synthesized by a new developed method via reaction of AgNO3 and oleic acid with the addition of a trace amount of Fe3+ ions. Emulsion polymerization at room temperature was employed to prepare a core-shell silver nanoparticle with controllable particle size. N,N'-methylenebisacrylamide (MBA and potassium peroxydisulfate (KPS were used as a crosslinker, and as redox initiator system, respectively for crosslinking polymerization. The structure and morphology of the silver nanogels were characterized by Fourier transform infrared spectroscopy (FTIR, transmission and scanning electron microscopy (TEM and SEM. The effectiveness of the synthesized compounds as corrosion inhibitors for steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. Monolayers of silver nanoparticle were self-assembled on the fresh active surface of the steel electrode and have been tested as a corrosion inhibitor for steel in 1 M HCl solution. The results of polarization measurements showed that nanogel particles act as a mixed type inhibitor.

Ultrasonic electrodeposition of silver nanoparticles on dielectric silica spheres

International Nuclear Information System (INIS)

Tang Shaochun; Tang Yuefeng; Gao Feng; Liu Zhiguo; Meng Xiangkang

2007-01-01

In the present study, a facile and one-step ultrasonic electrodeposition method is first applied to controllably coat colloidal silica spheres with silver nanoparticles. This method is additive-free and very direct, because processes necessary in many other approaches, such as pretreatment of the silica sphere surface and pre-preparation of silver nanoparticles, are not involved in it. Furthermore, it makes possible the coating of dielectric substrates with metal through an electrodeposition route. Under appropriate conditions, silver nanoparticles with sizes of 8-10 nm in diameter can be relatively homogeneously deposited onto the surface of preformed colloidal silica spheres. Silver particles with different sizes and dispersive uniformity on silica sphere surfaces can also be obtained by adjusting the current density (I), the concentration of electrolyte (C) and the electrolysis time (t). The possible ultrasonic electrodeposition mechanism is also suggested according to the experimental results

Development and Antibacterial Activity of Cashew Gum-Based Silver Nanoparticles

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Maria José dos S. Soares

2013-03-01

Full Text Available The present study describes the development of a green synthesis of silver nanoparticles reduced and stabilized by exuded gum from Anacardium occidentale L. and evaluates in vitro their antibacterial and cytotoxic activities. Characterization of cashew gum-based silver nanoparticles (AgNPs was carried out based on UV–Vis spectroscopy, transmission electron microscopy and dynamic light scattering analysis which revealed that the synthesized silver nanoparticles were spherical in shape, measuring about 4 nm in size with a uniform dispersal. AgNPs presented antibacterial activity, especially against Gram-negative bacteria, in concentrations where no significant cytotoxicity was observed.

Experimental study of mutagenous and mitosis modifying activity of silver nanoparticles

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B. S. Kirbik

2015-01-01

Full Text Available Mutagenous and mitosis modifying impact of silver nanoparticles has been studied on outbred mice. Nanoparticles were of round shape with dimensions of 5-50 nm, size of generated organic shell of 2-5 nm, the quantity in 1 mcm3 makes 120-270. Metaphasic analysis of mice bone marrow cells was used as a testing technique. The frequency of chromosome aberrations and mitotic index of preparations were accounted. During single intraperitoneal administration of the agent in the dose of 250 mcg/kg the silver nanoparticles demonstrated mitosis stimulating activity. No mutagenous effect of silver nanoparticles by daily administration for 4 days of 25 mcg/kg and single administration in the dose of 250 mcg/kg has been registered, but there is statistically insignificant tendency of aberrant metaphases increase. Consequently silver nanoparticles in the investigated doses demonstrated no mutagenous activity and can be considered safe for mammalian cells.

Speciation Matters: Bioavailability of Silver and Silver Sulfide Nanoparticles to Alfalfa (Medicago sativa).

Science.gov (United States)

Stegemeier, John P; Schwab, Fabienne; Colman, Benjamin P; Webb, Samuel M; Newville, Matthew; Lanzirotti, Antonio; Winkler, Christopher; Wiesner, Mark R; Lowry, Gregory V

2015-07-21

Terrestrial crops are directly exposed to silver nanoparticles (Ag-NPs) and their environmentally transformed analog silver sulfide nanoparticles (Ag2S-NPs) when wastewater treatment biosolids are applied as fertilizer to agricultural soils. This leads to a need to understand their bioavailability to plants. In the present study, the mechanisms of uptake and distribution of silver in alfalfa (Medicago sativa) were quantified and visualized upon hydroponic exposure to Ag-NPs, Ag2S-NPs, and AgNO3 at 3 mg total Ag/L. Total silver uptake was measured in dried roots and shoots, and the spatial distribution of elements was investigated using transmission electron microscopy (TEM) and synchrotron-based X-ray imaging techniques. Despite large differences in release of Ag(+) ions from the particles, Ag-NPs, Ag2S-NPs, and Ag(+) became associated with plant roots to a similar degree, and exhibited similarly limited (<1%) amounts of translocation of silver into the shoot system. X-ray fluorescence (XRF) mapping revealed differences in the distribution of Ag into roots for each treatment. Silver nanoparticles mainly accumulated in the (columella) border cells and elongation zone, whereas Ag(+) accumulated more uniformly throughout the root. In contrast, Ag2S-NPs remained largely adhered to the root exterior, and the presence of cytoplasmic nano-SixOy aggregates was observed. Exclusively in roots exposed to particulate silver, NPs smaller than the originally dosed NPs were identified by TEM in the cell walls. The apparent accumulation of Ag in the root apoplast determined by XRF, and the presence of small NPs in root cell walls suggests uptake of partially dissolved NPs and translocation along the apoplast.

Uncaria gambir Roxb. mediated green synthesis of silver nanoparticles using diethanolamine as capping agent

Science.gov (United States)

Labanni, A.; Zulhadjri; Handayani, D.; Arief, S.

2018-01-01

Studies of silver nanoparticles preparation has been developed increasingly due to the wide application in various areas and field, such as medicine, energy, catalysis, and electronic. An environmental-friendly method is needed to fabricate biocompatible silver nanoparticles without producing hazardous materials to the environment. In this study, we synthesized silver nanoparticles by green synthesis method, using leaf extract of gambir (Uncaria gambir Roxb.) as bioreducing agent and aqueous diethanolamine (DEA) solution as capping agents. The AgNO3/DEA molar ratio was varied to investigate the effect of DEA concentration to the properties of silver nanoparticles. The formation of silver nanoparticles was indicated by colour changes to yellowish brown and confirmed by result of UV-Vis spectrophotometer analysis which shown absorption band at 400 to 410 nm. The absorbance was increased to the reaction time of 24 hours, and was decrease by the increasing of DEA concentration in reaction. TEM analysis showed that prepared silver nanoparticles were spherical in shape with diameter of 3,5 - 45,5 nm. The diameter of DEA capped silver nanoparticles was 13 nm, smaller than uncapped silver nanoparticles which was 26 nm It exhibited good stability to time reaction of one month which was potential to be developed in some fields.

Green synthesis of silver nanoparticles using a Melissa officinalis leaf extract with antibacterial properties

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Álvaro de Jesús Ruíz-Baltazar

Full Text Available The exceptional properties of the silver nanoparticles offer several applications in the biomedicine field. The development of antibiotics which are clinically useful against bacteria and drug resistant microorganisms, it is one of the main approaches of silver nanoparticles. However, it is necessary to develop environmentally friendly methods for their synthesis. In this sense, the main objective of this work is focused on to propose a simplified and efficient green synthesis of silver nanoparticles with proven antibacterial properties. The green synthesis route is based on the use of the Melissa officinalis as reducing agent of the silver ions in aqueous solution at room temperature. Complementary, the antibacterial activity of the silver nanoparticles against Staphylococcus aureus and Escherichia coli was confirmed. The silver nanoparticles obtained were characterized by transmission electron microscopy, X-ray diffraction, UV–vis, Raman and FT-IR spectroscopy. The observed results suggested that using Melissa officinalis, it is possible to performed silver nanoparticles with controlled characteristics and with significant inhibitory activity against the Staphylococcus aureus and Escherichia coli. Keywords: Green synthesis, Nanoparticles, Antibacterial effect

Green synthesis of silver nanoparticles from seed extract of Brassica nigra and its antibacterial activity

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RAKSHA PANDIT

2015-05-01

Full Text Available Pandit R. 2015. Green synthesis of silver nanoparticles from seed extract of Brassica nigra and its antibacterial activity. Nusantara Bioscience 7: 15-19. We report the green synthesis of silver nanoparticles using seed extract of Brassica nigra. UV-visible spectroscopic analysis showed the absorbance peak at 432 nm which indicated the synthesis of silver nanoparticles. Nanoparticles Tracking and Analysis (NTA was used to determine the size of synthesized silver nanoparticles. Zeta potential analysis was carried out to study the stability of nanoparticles while FTIR analysis confirmed the presence of proteins as capping agents that provided stability to nanoparticles in colloid. Antibacterial activity of silver nanoparticles was evaluated against Propionibacterium acnes, Pseudomonas aeruginosa and Klebsiella pneumoniae. The activity of Vancomycin was significantly increased in combination with silver nanoparticles showing synergistic activity against all bacteria while the maximum activity was noted against P. acnes.

Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

Energy Technology Data Exchange (ETDEWEB)

Uznanski, Pawel, E-mail: puznansk@cbmm.lodz.pl; Zakrzewska, Joanna [Centre of Molecular and Macromolecular Studies, PAS (Poland); Favier, Frederic, E-mail: fredf@univ-montp2.fr [Université Montpellier II, ICGM - UMR5253- Equipe AIME (France); Kazmierski, Slawomir; Bryszewska, Ewa [Centre of Molecular and Macromolecular Studies, PAS (Poland)

2017-03-15

A comparative study of amine and silver carboxylate adducts [R{sub 1}COOAg-2(R{sub 2}NH{sub 2})] (R{sub 1} = 1, 7, 11; R{sub 2} = 8, 12) as a key intermediate in NPs synthesis is carried out via differential scanning calorimetry, solid-state FT-infrared spectroscopy, {sup 13}C CP MAS NMR, powder X-ray diffraction and X-ray photoelectron spectroscopy, and various solution NMR spectroscopies ({sup 1}H and {sup 13}C NMR, pulsed field gradient spin-echo NMR, and ROESY). It is proposed that carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination as opposed to bridging bidentate coordination of pure silver carboxylates resulting from the formation of dimeric units. All complexes are packed as lamellar bilayer structures. Silver carboxylate/amine complexes show one first-order melting transition. The evidence presented in this study shows that phase behavior of monovalent metal carboxylates are controlled, mainly, by head group bonding. In solution, insoluble silver salt is stabilized by amine molecules which exist in dynamic equilibrium. Using (bis)amine-silver carboxylate complex as precursor, silver nanoparticles were fabricated. During high-temperature thermolysis, the (bis)amine-carboxylate adduct decomposes to produce silver nanoparticles of small size. NPs are stabilized by strongly interacting carboxylate and trace amounts of amine derived from the silver precursor interacting with carboxylic acid. A corresponding aliphatic amide obtained from silver precursor at high-temperature reaction conditions is not taking part in the stabilization. Combining NMR techniques with FTIR, it was possible to follow an original stabilization mechanism.

Green Synthesis of Silver Nanoparticles and the Study of Optical Properties

Directory of Open Access Journals (Sweden)

Ramakrishna Vasireddy

2012-08-01

Full Text Available The synthesis of silver nanoparticles of varying size has been achieved using different molar concentrations of NaOH while the effect of changing the temperature has been studied. AgNO3, gelatine, glucose and NaOH are used as a silver precursor, stabilizer, reducing agent and accelerator respectively. The synthesized nanoparticles have been characterized by a FESEM study, X‐ray diffractometry, Raman spectroscopy and UV‐vis spectroscopy. The colloidal sols of the silver nanoparticles in a biopolymer gelatine show strong surface plasmon resonance absorption peaks. The visible photoluminescence emission from the synthesized silver nanocrystals has been recorded within the wavelength range of 400‐600 nm under UV excitation. The synthesized nanoparticles may be extremely useful in making biosensor devices as well as for other applications.

Synthesis, characterization and optical properties of gelatin doped with silver nanoparticles

Science.gov (United States)

Mahmoud, K. H.; Abbo, M.

2013-12-01

In this study, silver nanoparticles were synthesized by chemical reduction of silver salt (AgNO3) solution. Formation of nanoparticles was confirmed by UV-visible spectrometry. The surface plasmon resonance peak is located at 430 nm. Doping of silver nanoparticles (Ag NPs) with gelatin biopolymer was studied. The silver content in the polymer matrix was in the range of 0.4-1 wt%. The formation of nanoparticles disappeared for silver content higher than 1 wt%. The morphology and interaction of gelatin doped with Ag NPs was examined by transmission electron microscopy and FTIR spectroscopy. The content of Ag NPs has a pronounced effect on optical and structural properties of gelatin. Optical parameters such as refractive index, complex dielectric constant were calculated. The dispersion of the refractive index was discussed in terms of the single - oscillator Wemple-DiDomenico model. Color properties of the prepared samples were discussed in the framework of CIE L*u*v* color space.

Size Control Technology of Silver Nanoparticles Using Electron Beam Irradiation

International Nuclear Information System (INIS)

Kang, Hyun Suk; Kim, Byungnam; Kim, Hye Won; Koo, Yong Hwan; Lee, Byung Cheol; Park, Ji Hyun; Bae, Hyung Bin; Park, Changmoon

2013-01-01

The manufacturing of silver nanoparticles using an electron beam is easy, fast, and highly productive, and it is possible at room temperature with no chemical residuals. Its various advantages therefore make this an important method for manufacturing nanoparticles such as silver, copper, and platinum. In particular, despite the use of electron beam irradiation, the results show that this method makes it possible to produce silver nanoparticles at low cost since low beam energy and low doses are used. This means that middle and high-energy electron beam accelerators are very expensive, but a low-energy electron beam accelerator has a relatively low cost of around 4-5 times, and mass production for a flow reaction without the need for extra radiation shielding is possible. Silver nanoparticles are of great interest to many researchers owing to their ability to be used in many applications such as catalysis, nanoelectronics, optical filters, electromagnetic interference shielding, surface Raman scattering, medical supplies, fabrics, cosmetics, hygiene and kitchen supplies, and electric home appliances

Size Control Technology of Silver Nanoparticles Using Electron Beam Irradiation

Energy Technology Data Exchange (ETDEWEB)

Kang, Hyun Suk; Kim, Byungnam; Kim, Hye Won; Koo, Yong Hwan; Lee, Byung Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Ji Hyun [Univ. of Science and Technology, Daejeon (Korea, Republic of); Bae, Hyung Bin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Park, Changmoon [Chungnam National Univ., Daejeon (Korea, Republic of)

2013-12-15

The manufacturing of silver nanoparticles using an electron beam is easy, fast, and highly productive, and it is possible at room temperature with no chemical residuals. Its various advantages therefore make this an important method for manufacturing nanoparticles such as silver, copper, and platinum. In particular, despite the use of electron beam irradiation, the results show that this method makes it possible to produce silver nanoparticles at low cost since low beam energy and low doses are used. This means that middle and high-energy electron beam accelerators are very expensive, but a low-energy electron beam accelerator has a relatively low cost of around 4-5 times, and mass production for a flow reaction without the need for extra radiation shielding is possible. Silver nanoparticles are of great interest to many researchers owing to their ability to be used in many applications such as catalysis, nanoelectronics, optical filters, electromagnetic interference shielding, surface Raman scattering, medical supplies, fabrics, cosmetics, hygiene and kitchen supplies, and electric home appliances.

Facile synthesis of silver nanoparticles and their application in dye degradation

Energy Technology Data Exchange (ETDEWEB)

Joseph, Siby, E-mail: sibyjoseph4@gmail.com [Department of Chemistry, St. George' s College, Aruvithura, Kottayam 686122, Kerala (India); Mathew, Beena, E-mail: beenamscs@gmail.com [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, Kerala (India)

2015-05-15

Graphical abstract: - Highlights: • This synthetic method uses the novel reducing agent hexamine. • The method is simple, fast and environment friendly. • This is a cost-effective method as all materials used are inexpensive and readily available. • The method provides highly stable spherical silver nanoparticles. • The nanoparticles show outstanding catalytic activity in the degradation of organic dyes. - Abstract: The present article reports a simple, facile and eco-friendly method based on microwave irradiation for the synthesis of silver nanoparticles in aqueous medium using starch as stabilizing agent and a new reducing agent namely hexamine. The silver nanoparticles were characterized by UV–vis, FTIR, XRD and HR-TEM analysis. UV–vis spectroscopic studies provided sufficient evidences for the formation of nanoparticles. The role of starch in the synthesis and stabilization of the nanoparticles was obtained from FTIR studies. The XRD and HR-TEM investigations clearly demonstrated the crystalline nature of the nanoparticles. From the TEM images, the silver nanoparticles were found to be spherical and of nearly uniform size with an average diameter of 18.2 ± 0.97 nm. The nanoparticles showed excellent catalytic activity in the degradation of methyl orange and rhodamine B by NaBH{sub 4}.

Facile synthesis of silver nanoparticles and their application in dye degradation

International Nuclear Information System (INIS)

Joseph, Siby; Mathew, Beena

2015-01-01

Graphical abstract: - Highlights: • This synthetic method uses the novel reducing agent hexamine. • The method is simple, fast and environment friendly. • This is a cost-effective method as all materials used are inexpensive and readily available. • The method provides highly stable spherical silver nanoparticles. • The nanoparticles show outstanding catalytic activity in the degradation of organic dyes. - Abstract: The present article reports a simple, facile and eco-friendly method based on microwave irradiation for the synthesis of silver nanoparticles in aqueous medium using starch as stabilizing agent and a new reducing agent namely hexamine. The silver nanoparticles were characterized by UV–vis, FTIR, XRD and HR-TEM analysis. UV–vis spectroscopic studies provided sufficient evidences for the formation of nanoparticles. The role of starch in the synthesis and stabilization of the nanoparticles was obtained from FTIR studies. The XRD and HR-TEM investigations clearly demonstrated the crystalline nature of the nanoparticles. From the TEM images, the silver nanoparticles were found to be spherical and of nearly uniform size with an average diameter of 18.2 ± 0.97 nm. The nanoparticles showed excellent catalytic activity in the degradation of methyl orange and rhodamine B by NaBH 4

Synthesis and characterization of titania-based monodisperse fluorescent europium nanoparticles for biolabeling

International Nuclear Information System (INIS)

Tan Mingqian; Wang Guilan; Ye Zhiqiang; Yuan Jingli

2006-01-01

Inorganic-organic hybrid titania-based nanoparticles covalently bound to a fluorescent Eu 3+ chelate of 4,4'-bis(1'',1'',1'',2'',2'',3'',3''-heptafluoro-4'',6''-hexanedion-6''-yl) chlorosulfo-o-terphenyl (BHHCT-Eu 3+ ) were synthesized by a sol-gel technique. A conjugate of BHHCT with 3-[2-(2-aminoethylamino) ethylamino]propyl-trimethoxysilane (APTS) was used as a precursor for the nanoparticle preparation and monodisperse nanoparticles consisting of titania network and silica sub-network covalently bound to the Eu 3+ chelate were prepared by the copolymerization of APTS-BHHCT conjugate, titanium tetraisopropoxide (TTIP) and free APTS in EuCl 3 water-alcohol solution. The effects of reaction conditions on size and fluorescence lifetime of the nanoparticles were investigated. The characterizations by transmission electron microscopy and fluorometric methods indicate that the nanoparticles are near spherical and strongly fluorescent having a fluorescence quantum yield of 11.6% and a long fluorescence lifetime of ∼0.4 ms. The direct-introduced amino groups on the nanoparticle's surface by using free APTS in nanoparticle preparation facilitated the biolabeling process of the nanoparticles. The nanoparticle-labeled streptavidin (SA) was prepared and used in a sandwich-type time-resolved fluoroimmunoassay (TR-FIA) of human prostate-specific antigen (PSA) by using a 96-well microtiter plate as the solid phase carrier. The method gives a detection limit of 66 pg/ml for the PSA assay

Release of silver nanoparticles from outdoor facades

International Nuclear Information System (INIS)

Kaegi, Ralf; Sinnet, Brian; Zuleeg, Steffen; Hagendorfer, Harald; Mueller, Elisabeth; Vonbank, Roger; Boller, Markus; Burkhardt, Michael

2010-01-01

In this study we investigate the release of metallic silver nanoparticles (Ag-NP) from paints used for outdoor applications. A facade panel mounted on a model house was exposed to ambient weather conditions over a period of one year. The runoff volume of individual rain events was determined and the silver and titanium concentrations of 36 out of 65 runoff events were measured. Selected samples were prepared for electron microscopic analysis. A strong leaching of the Ag-NP was observed during the initial runoff events with a maximum concentration of 145 μ Ag/l. After a period of one year, more than 30% of the Ag-NP were released to the environment. Particles were mostly 2 S. - We provide direct evidence for the release of silver nanoparticles from exterior paints to the aquatic environment.

Biogenic silver and gold nanoparticles synthesized using red ginseng root extract, and their applications.

Science.gov (United States)

Singh, Priyanka; Kim, Yeon Ju; Wang, Chao; Mathiyalagan, Ramya; El-Agamy Farh, Mohamed; Yang, Deok Chun

2016-05-01

In the present study, we report a green methodology for the synthesis of silver and gold nanoparticles, using the root extract of the herbal medicinal plant Korean red ginseng. The silver and gold nanoparticles were synthesized within 1 h and 10 min respectively. The nanoparticles generated were not aggregated, and remained stable for a long time, which suggests the nature of nanoparticles. The phytochemicals and ginsenosides present in the root extract assist in reducing and stabilizing the synthesized nanoparticles. The red ginseng root extract-generated silver nanoparticles exhibit antimicrobial activity against pathogenic microorganisms including Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus, and Candida albicans. In addition, the silver nanoparticles exhibit biofilm degrading activity against S. aureus and Pseudomonas aeruginosa. Thus, the present study opens up a new possibility of synthesizing silver and gold nanoparticles in a green and rapid manner using Korean red ginseng root extract, and explores their biomedical applications.

Complex conductivity response to silver nanoparticles in partially saturated sand columns

Science.gov (United States)

Abdel Aal, Gamal; Atekwana, Estella A.; Werkema, D. Dale

2017-02-01

The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research needs include knowledge and methods for their detection, characterization, fate, and transport. Specifically, techniques available for the direct detection and quantification of their fate and transport in the environment are limited. Their small size, high surface area to volume ratio, interfacial, and electrical properties make metallic nanoparticles, such as silver nanoparticles, good targets for detection using electrical geophysical techniques. Here we measured the complex conductivity response to silver nanoparticles in sand columns under varying moisture conditions (0-30%), nanoparticle concentrations (0-10 mg/g), lithology (presence of clay), pore water salinity (0.0275 and 0.1000 S/m), and particle size (35, 90-210 and 1500-2500 nm). Based on the Cole-Cole relaxation models we obtained the chargeability and the time constant. We demonstrate that complex conductivity can detect silver nanoparticles in porous media with the response enhanced by higher concentrations of silver nanoparticles, moisture content, ionic strength, clay content and particle diameter. Quantification of the volumetric silver nanoparticles content in the porous media can also be obtained from complex conductivity parameters based on the strong power law relationships.

Biosynthesized Silver Nanoparticles Used in Preservative Solutions for Chrysanthemum cv. Puma

Directory of Open Access Journals (Sweden)

Luis M. Carrillo-López

2016-01-01

Full Text Available The use of pulse solutions containing antimicrobials has been reported, but more research is necessary. To increase vase life and to study their effect on opening inflorescences, silver nanoparticles were used in vase solutions for cv. Puma Chrysanthemum stems. The nanoparticles were synthesized biologically using Chenopodium ambrosioides L. applied at concentrations of 0.01, 0.05, 0.1, 0.5, 1, and 5 mM and compared with a control. Treatments were replicated five times. The stems were cut to 50 cm and observed until the end of their vase life. Low concentrations of silver nanoparticles promoted inflorescence opening and leaf yellowing, while the control leaves remained green, but there was a lower degree of inflorescence opening. High concentrations of silver nanoparticles (0.5, 1, and 5 mM caused senescence due to low water uptake through the stems. Statistical differences in inflorescence opening and diameter, bacterial growth (CFU mL−1 in vase solutions, fresh weight, water uptake, and vase life were found among treatments. Longer vase life and less weight loss were observed in the stems exposed to low concentrations of silver nanoparticles. Low concentrations of silver nanoparticles promoted inflorescence opening and increased vase life of Chrysanthemum cv. Puma.

Temperature evolution in silver nanoparticle doped PETN composite

Science.gov (United States)

Kameswari, D. P. S. L.; Kiran, P. Prem

2018-04-01

Optical absorption and the associated spatio-temporal evolution of temperature silver nanoparticles doped energetic material composite is presented. Silver nanoparticles of radii 10 - 150 nm are doped in Penta Erythrtol Tetra Nitrate (PETN), a secondary energetic material to form the composite materials. Of all the composites the ones doped with 35 nm sized nanoparticles have shown maximum absorption at excitation wavelength of 532 nm. The spatio-temporal evolution of temperature within these composites up on excitation with ns laser pulses of energy density 0.5 J/cm2 is studied. The role of particle sizes on the temperature of composites is studied and a maximum temperature of 2200 K at the nanoparticle interface is observed for 35 nm doped PETN composite.

Impact of silver ions and silver nanoparticles on the plant growth and soil microorganisms

Directory of Open Access Journals (Sweden)

D. Tomacheski

2017-12-01

Full Text Available There is a growing consumer market for products that proclaim to decrease microorganism counts to prevent infections. Most of these products are loaded with silver in its ionic or nanoparticle form. Through use or during production, these particles can find their way into the soil and cause an impact in microbial and plant communities. This study aims to evaluate the impact of silver based particles in Avena byzantina (oat, Lactuca sativa (lettuce and Raphanus sativus (radish development and in the soil microorganism abundance. Oat, lettuce and radish plants were cultivated in soil contaminated with particles of bentonite organomodified with silver (Ag+_bentonite, silver phosphate glass (Ag+_phosphate and silver nanoparticles adsorbed on fumed silica (AgNp_silica. Plant development and microorganisms’ abundance were evaluated. To some degree, Ag+_bentonite impacted plants development and AgNp_silica causes an adverse effect on microbial abundance. The impact on plants and microorganisms was contradictory and varied according to soil and particles physicochemical characteristics.

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

Science.gov (United States)

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

2013-10-01

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

Response of three instruments devoted to surface-area for monodisperse and polydisperse aerosols in molecular and transition regimes

International Nuclear Information System (INIS)

Bau, Sebastien; Witschger, Olivier; Gensdarmes, Francois; Thomas, Dominique

2011-01-01

An increasing number of experimental and theoretical studies focus on airborne nanoparticles (NP) in relation with many aspects of risk assessment. Indeed, our understanding of the hazards, the actual exposures in the workplace and the limits of engineering controls and personal protective equipment with regard to NP are still under development. Several studies have already identified surface-area as an important determinant of low solubility nanoparticles toxicity. As a consequence, the concept that surface-area could be a relevant metric for characterizing exposure to low solubility airborne NP has been proposed [1]. To provide NP surface-area concentration, some direct-reading instruments have been designed, based on diffusion charging. The actual available instruments providing airborne NP surface-area concentration are studied in this work: LQ1-DC (Matter Engineering), AeroTrak T M 9000 (TSI) and NSAM (TSI model 3550). Their performances regarding monodisperse carbon NP have been investigated by Bau et al.. This work aims at completing the instruments characterization regarding monodisperse NP of other chemical composition (aluminium, copper, silver) and studying their performances against polydisperse aerosols of NP.

Response of three instruments devoted to surface-area for monodisperse and polydisperse aerosols in molecular and transition regimes

Energy Technology Data Exchange (ETDEWEB)

Bau, Sebastien; Witschger, Olivier [Institut National de Recherche et de Securite (INRS), Laboratoire de Metrologie des Aerosols, Rue du Morvan, CS 60027, 54519 Vandoeuvre Cedex (France); Gensdarmes, Francois [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Physique et de Metrologie des Aerosols, BP 68, 91192 Gif-sur-Yvette (France); Thomas, Dominique, E-mail: sebastien.bau@inrs.fr [Laboratoire Reactions et Genie des Procedes (LRGP), groupe SAFE, 1 rue Grandville, BP 20041, 54001 Nancy Cedex (France)

2011-07-06

An increasing number of experimental and theoretical studies focus on airborne nanoparticles (NP) in relation with many aspects of risk assessment. Indeed, our understanding of the hazards, the actual exposures in the workplace and the limits of engineering controls and personal protective equipment with regard to NP are still under development. Several studies have already identified surface-area as an important determinant of low solubility nanoparticles toxicity. As a consequence, the concept that surface-area could be a relevant metric for characterizing exposure to low solubility airborne NP has been proposed [1]. To provide NP surface-area concentration, some direct-reading instruments have been designed, based on diffusion charging. The actual available instruments providing airborne NP surface-area concentration are studied in this work: LQ1-DC (Matter Engineering), AeroTrak{sup TM} 9000 (TSI) and NSAM (TSI model 3550). Their performances regarding monodisperse carbon NP have been investigated by Bau et al.. This work aims at completing the instruments characterization regarding monodisperse NP of other chemical composition (aluminium, copper, silver) and studying their performances against polydisperse aerosols of NP.

Biosynthesis of silver nanoparticles using lingonberry and cranberry juices and their antimicrobial activity.

Science.gov (United States)

Puišo, Judita; Jonkuvienė, Dovilė; Mačionienė, Irena; Šalomskienė, Joana; Jasutienė, Ina; Kondrotas, Rokas

2014-09-01

In this study lingonberry and cranberry juices were used for silver nanoparticle synthesis. The berry juices were characterized by total phenolics, total anthocyanins and benzoic acid content, respectively 1.9-2.7mg/ml, 55.2-83.4mg/l and 590.8-889.2mg/l. The synthesis of silver nanoparticles was performed at room temperature assisting in solutions irradiated by ultraviolet for 30min. Ultraviolet-visible (UV-vis) spectroscopy and microscopy confirmed the formation of nanoparticles as well as the dark red color of colloid of silver samples showed the formation of stable nanoparticles. Broad localized surface plasmon resonance (LSPR) peaks in UV-vis spectra indicated the formation of polydispersive silver nanoparticles and LSPR was observed at 485nm and 520nm for the silver nanoparticles synthesis using lingonberry and cranberry juices, respectively. The antimicrobial activity of silver nanoparticles was determined against the reference strains of microorganisms that could be found in food products: Staphylococcus aureus ATCC 25923, Salmonella typhimurium ATCC 13076, Listeria monocytogenes ATCC 19111, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231 and foodborne B. cereus producing and non-producing enterotoxins. Silver nanoparticles showed a broad spectrum of antimicrobial activity and were most active against S. aureus ATCC 25923, B. subtilis ATCC 6633 and B. cereus ATCC 11778 reference cultures, and less active against C. albicans ATCC 10231 and foodborne B. cereus. It can be concluded that lingonberry and cranberry juices could be used as bioreductants for silver ions. Copyright © 2014 Elsevier B.V. All rights reserved.

Silver Nanoparticles Modification of Ultra High Molecular Weight Polyethylene in Non-Aqueous Medium

OpenAIRE

V. N. Glushko; L. I. Blokhina; E. E. Anisimova; M. V. Bogdanovskaya; V. I. Kozhukhov; T. A. Cherdyntseva

2016-01-01

A series of experiments for obtaining modified with silver nanoparticles ultra-high molecular weight polyethylene (UHMWPE) is done. Optimal precursors are silver trifluoroacetate, silver nitrate and silver methanesulfonate. Three variants of UHMWPE modification is studied: 1) the polyol synthesis, 2) polymer processing silver nanoparticle colloid and 3) reduction of silver salt solution in the UHMWPE polymer matrix. It is found that the last method is optimal. The specific surface of obtained...

Synthesis and characterization of silver nanoparticle composite with poly(p-Br-phenylsilane).

Science.gov (United States)

Kim, Myoung-Hee; Lee, Jun; Mo, Soo-Yong; Woo, Hee-Gweon; Yang, Kap Seung; Kim, Bo-Hye; Lee, Byeong-Gweon; Sohn, Honglae

2012-05-01

The one-pot synthesis and characterization of silver nanoparticle-poly(p-Br-phenylsilane) composites have been carried out. The conversion of silver(+1) salt to stable silver(0) nanoparticles is promoted by poly(p-Br-phenylsilane), Br-PPS possessing both possible reactive Si-H bonds in the polymer backbone and C-Br bonds in the substituents. The composites were characterized using XRD, TEM, FE-SEM, and solid-state UV-vis analytical techniques. TEM and FE-SEM data show the formation of the composites where large number of silver nanoparticles (less than 30 nm of size) are well dispersed throughout the Br-PPS matrix. XRD patterns are consistent with that for fcc-typed silver. The elemental analysis for Br atom and the polymer solubility confirm that the cleavage of C-Br bond and the Si-Br dative bonding were not occurred appreciably at ambient temperature. Nonetheless, TGA data suggest that some sort of cross-linking was occurred at high temperature. The size and processability of such nanoparticles depend on the ratio of metal to Br-PPS. In the absence of Br-PPS, most of the silver particles undergo macroscopic aggregation, which indicates that the polysilane is necessary for stabilizing the silver nanoparticles.

Photocatalytic and antibacterial properties of a TiO2/nylon-6 electrospun nanocomposite mat containing silver nanoparticles

International Nuclear Information System (INIS)

Pant, Hem Raj; Pandeya, Dipendra Raj; Nam, Ki Taek; Baek, Woo-il; Hong, Seong Tshool; Kim, Hak Yong

2011-01-01

Silver-impregnated TiO 2 /nylon-6 nanocomposite mats exhibit excellent characteristics as a filter media with good photocatalytic and antibacterial properties and durability for repeated use. Silver nanoparticles (NPs) were successfully embedded in electrospun TiO 2 /nylon-6 composite nanofibers through the photocatalytic reduction of silver nitrate solution under UV-light irradiation. TiO 2 NPs present in nylon-6 solution were able to cause the formation of a high aspect ratio spider-wave-like structure during electrospinning and facilitated the UV photoreduction of AgNO 3 to Ag. TEM images, UV-visible and XRD spectra confirmed that monodisperse Ag NPs (approximately 4 nm in size) were deposited selectively upon the TiO 2 NPs of the prepared nanocomposite mat. The antibacterial property of a TiO 2 /nylon-6 composite mat loaded with Ag NPs was tested against Escherichia coli, and the photoactive property was tested against methylene blue. All of the results showed that TiO 2 /nylon-6 nanocomposite mats loaded with Ag NPs are more effective than composite mats without Ag NPs. The prepared material has potential as an economically friendly photocatalyst and water filter media because it allows the NPs to be reused.

Sensing of silver nanoparticles on/in endothelial cells using atomic force spectroscopy.

Science.gov (United States)

Kolodziejczyk, Agnieszka; Jakubowska, Aleksandra; Kucinska, Magdalena; Wasiak, Tomasz; Komorowski, Piotr; Makowski, Krzysztof; Walkowiak, Bogdan

2018-05-10

Endothelial cells, due to their location, are interesting objects for atomic force spectroscopy study. They constitute a barrier between blood and vessel tissues located deeper, and therefore they are the first line of contact with various substances present in blood, eg, drugs or nanoparticles. This work intends to verify whether the mechanical response of immortalized human umbilical vein endothelial cells (EA.hy926), when exposed to silver nanoparticles, as measured using force spectroscopy, could be effectively used as a bio-indicator of the physiological state of the cells. Silver nanoparticles were characterized with transmission electron microscopy and dynamic light scattering techniques. Tetrazolium salt reduction test was used to determine cell viability after treatment with silver nanoparticles. An elasticity of native cells was examined in the Hanks' buffer whereas fixed cells were softly fixed with formaldehyde. Additional aspect of the work is the comparative force spectroscopy utilizing AFM probes of ball-shape and conical geometries, in order to understand what changes in cell elasticity, caused by SNPs, were detectable with each probe. As a supplement to elasticity studies, cell morphology observation by atomic force microscopy and detection of silver nanoparticles inside cells using transmission electron microscopy were also performed. Cells exposed to silver nanoparticles at the highest selected concentrations (3.6 μg/mL, 16 μg/mL) are less elastic. It may be associated with the reorganization of the cellular cytoskeleton and the "strengthening" of the cell cortex caused by presence of silver nanoparticles. This observation does not depend on cell fixation. Agglomerates of silver nanoparticles were observed on the cell membrane as well as inside the cells. Copyright © 2018 John Wiley & Sons, Ltd.

Novel method for the preparation of core-shell nanoparticles with movable Ag core and polystyrene loop shell

International Nuclear Information System (INIS)

Liu Weijun; Zhang Zhicheng; He Weidong; Zheng Cheng; Ge Xuewu; Li, Jian; Liu Huarong; Jiang Hao

2006-01-01

Core/shell nanoparticles with movable silver (Ag) core and polystyrene (PSt) shell (Ag at PSt nanoparticle) were successfully synthesized at room temperature and under ambient pressure via two steps: γ-irradiation and interfacial-initiated polymerization. Firstly, mono-dispersed Ag nanoparticles with diameters 20 nm were synthesized in inversed microemulsion by reducing silver nitrate under γ-irradiation. Then, Ag nanoparticles were coated with PSt via interfacial-initiated polymerization with cumene hydroperoxide/ferrous sulfate/disodium ethylenediaminetetraacetate/sodium formaldehyde sulfoxylate (CHPO-Fe 2+ -EDTA-SFS) as the redox initiation pair. The resulted Ag at PSt nanoparticles were identified by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS)

Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System

Science.gov (United States)

Liu, J.; Burrow, E.; Hwang, Y.; Lenhart, J.

2013-12-01

Nanoparticles are increasingly being used in industrial processes and consumer products that exploit their beneficial properties and improve our daily lives. Nevertheless, they also attract attention when released into natural environment due to their potential for causing adverse effects. The fate and transport of nanoparticles in aqueous systems have been the focus of intense study. However, their interactions with other natural particles have received only limited attention. Clay minerals are ubiquitous in most aquatic systems and their variably charged surfaces can act as deposition sites that can alter the fate and transport of nanoparticles in natural aqueous environments. In this study, we investigated the homoaggregation of silver nanoparticles with different coating layers and their heteroaggregation behavior with clay minerals (illite, kaolinite, montmorillonite) in neutral pH solutions. Silver nanoparticles with a nominal diameter of 80 nm were synthesized with three different surface coating layers: uncoated, citrate-coated and Tween-coated. Illite (IMt-2), kaolinite (KGa-2), and montmorillonite (SWy-2) were purchased from the Clay Mineral Society (Indiana) and pretreated to obtain monocationic (Na-clay) and dicationic (Ca-clay) suspensions before the experiments. The change in hydrodynamic diameter as a function of time was monitored using dynamic light scattering (DLS) measurements in order to evaluate early stage aggregation as a function of electrolyte concentration in both the homo- and heteroaggregation scenarios. A shift in the critical coagulation concentration (CCC) values to lower electrolyte concentrations was observed in binary systems, compared to single silver nanoparticle and clay systems. The results also suggest more rapid aggregation in binary system during the early aggregation stage when compared to the single-particle systems. The behavior of citrate-coated silver nanoparticles was similar to that of the bare particles, while the

Characterization of silver nanoparticles prepared by wet chemical ...

African Journals Online (AJOL)

Results: The silver nanoparticles formed were spherical in shape with mean size of 10.3 nm. The ... antibacterial activity against various strains of bacteria. Keywords: Wet ..... Fang J, Zhong C, Mu R. The study of deposited silver particulate ...

Surface Phenomena at Silver Nanoparticles in the Context of Toxicology

DEFF Research Database (Denmark)

Miclaus, Teodora

2015-01-01

Nanoparticle research and applications are rapidly expanding areas and large scale production and use of nanomaterials has prompted concern regarding their safety for humans and the environment. Nanotoxicology aims to offer answers to issues that may arise in regards to potential harmful effects...... associated with engineered nanomaterials. Among these materials, silver nanoparticles are some of the most widely employed and thus represent a major point of focus in nanotoxicology and the topic of this PhD thesis. While nanoparticles have, upon synthesis, well-defined characteristics, specific...... of nanotoxicology. The main aim of this PhD research is to investigate these phenomena at the surface of silver nanoparticles under conditions that are relevant for in vitro studies in order to understand their implications for nano-silver toxicity. Upon contact with biological fluids, particles get coated...

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

Science.gov (United States)

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

2014-07-01

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

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].

Green Synthesis of Silver Nanoparticles Using Pimpinella anisum L. Seed Aqueous Extract and Its Antioxidant Activity

Directory of Open Access Journals (Sweden)

Hashem Akhlaghi

2015-09-01

Full Text Available An aqueous extract of Pimpinella anisum was used for green synthesis of silver nanoparticles by bio reduction of an aqueous solution of silver nitrate. Silver nanoparticles were characterized by UV–Vis spectrometry, Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD analysis, scanning electron microscopy (SEM and energy-dispersive X-ray analysis (EDAX. The increase in absorption at 420 nm was used for recording the formation of a colloidal suspension of silver nanoparticles. The binding properties of the capped Ag nanoparticles synthesized from aqueous extract of P. anisum were analyzed by FTIR. XRD studies revealed that most of the nanoparticles were cubic and face centered cubic in shape. SEM analysis showed the size and shape of silver nanoparticles and EDAX confirmed the presence of silver. The synthesized silver nanoparticles showed DPPH free radical scavenging activity.

Formation of nanoparticles from thin silver films irradiated by laser pulses in air

Science.gov (United States)

Nastulyavichus, A. A.; Smirnov, N. A.; Kudryashov, S. I.; Ionin, A. A.; Saraeva, I. N.; Busleev, N. I.; Rudenko, A. A.; Khmel'nitskii, R. A.; Zayarnyi, D. A.

2018-03-01

Some specific features of the transport of silver nanoparticles onto a SiO2 substrate under focused nanosecond IR laser pulses is experimentally investigated. A possibility of obtaining silver coatings is demonstrated. The formation of silver nanostructures as a result of pulsed laser ablation in air is studied. Nanoparticles are formed by exposing a silver film to radiation of an HTF MARK (Bulat) laser marker (λ = 1064 nm). The thus prepared nanoparticles are analysed using scanning electron microscopy and optical spectroscopy.

Biosynthesis of Silver Nanoparticles Using Oscillatoria Extract and Evaluation the Anticancer and Antibacterial Activities

Directory of Open Access Journals (Sweden)

T Ghasemipour

2017-07-01

Full Text Available Abstract Background and aim: The emergence of nanotechnology is one of the most promising areas for medical research. Today, biological methods of synthesizing nanoparticles have been considered in the fight against many diseases. The purpose of this study was to evaluate the anti-cancer and anti-bacterial activity of silver nanoparticles, biosynthesized with cyanobacteria acetate extract. Methods: In the present experimental study, the silver nanoparticles biosynthesis was performed using silver ions regeneration with cyanobacteria acetate extracts. Techniques such as X-ray diffraction, scanning electron microscopy and transient evaluation of silver nanoparticles were evaluated. In order to investigate the antibacterial activity of synthesized nanosilver, serial dilution method was used for broth microdilution test to determine minimum inhibitory concentration (MIC. The effects of silver nanoparticle toxicity on T47D breast cancer cell line were evaluated using MTT colorimetric method. Also, the proximal anxine 0.5 propidoid yodide kit and flow cytometry system were evaluated to evaluate the percentage of apoptosis and necrosis in cancer cells treated with silver nanoparticles. Results: Characterization of biosynthetic silver nanoparticles indicated that these nanoparticles had a mean size of 30 nm with dominant spherical morphology. The evaluation of the antibacterial properties of biosynthetic nanoparticles showed that the minimum inhibitory concentration for Escherichia coli, Acinetobacter Bumanni and Staphylococcus aureus was 25, 50 and 12.5 μg / ml, respectively. The results of cell proliferation of nanoparticles showed that its effect depends on the concentration and time of treatment of silver nanoparticles on cancerous cells. In addition, flow cytometric results showed an apoptotic cell death rate of 35% in the T47D cell line. Conclusion: Biosynthesis nanoparticles have anticancer and antibacterial activity and can be studied further

Simple and environmentally friendly preparation and size control of silver nanoparticles using an inhomogeneous system with silver-containing glass powder

International Nuclear Information System (INIS)

Mori, Yasutaka; Tagawa, Toshio; Fujita, Masanori; Kuno, Toyohiko; Suzuki, Satoshi; Matsui, Takemi; Ishihara, Masayuki

2011-01-01

A simple, environmentally friendly method for preparing highly size-controlled spherical silver nanoparticles was developed that involved heating a mixture of silver-containing glass powder and an aqueous solution of glucose. The stabilizing agent for silver nanoparticles was found to be caramel, which was generated from glucose when preparing the nanoparticles. The particle size was independent of the reaction time, but it increased proportionally with the square root of the glucose concentration in the range 0.25–8.0 wt% (corresponding to particle sizes of 3.48 ± 1.83 to 20.0 ± 2.76 nm). Difference of the generation mechanism of silver nanoparticles between this inhomogeneous system and a system in which Ag + was homogeneously dispersed was discussed.

Silver nanoparticle-E. coli colloidal interaction in water and effect on E. coli survival.

Science.gov (United States)

Dror-Ehre, A; Mamane, H; Belenkova, T; Markovich, G; Adin, A

2009-11-15

Silver nanoparticles exhibit antibacterial properties via bacterial inactivation and growth inhibition. The mechanism is not yet completely understood. This work was aimed at elucidating the effect of silver nanoparticles on inactivation of Escherichia coli, by studying particle-particle interactions in aqueous suspensions. Stable, molecularly capped, positively or negatively charged silver nanoparticles were mixed at 1 to 60microgmL(-1) with suspended E. coli cells to examine their effect on inactivation of the bacteria. Gold nanoparticles with the same surfactant were used as a control, being of similar size but made up of a presumably inert metal. Log reduction of 5log(10) and complete inactivation were obtained with the silver nanoparticles while the gold nanoparticles did not show any inactivation ability. The effect of molecularly capped nanoparticles on E. coli survival was dependent on particle number. Log reduction of E. coli was associated with the ratio between the number of nanoparticles and the initial bacterial cell count. Electrostatic attraction or repulsion mechanisms in silver nanoparticle-E. coli cell interactions did not contribute to the inactivation process.

Preparation of amine coated silver nanoparticles using ...

Indian Academy of Sciences (India)

Administrator

concentrations without the precipitation of particles. In this work, an analysis of the temperature influ- ence on the precipitation of silver nanoparticles was carried out. Also, the nanoparticles were func- tionalized using triethylenetetramine in order to im- prove the adhesion between the epoxy resin and the filler.

Silver Nanoparticles and Studies on Using in Poultry Nutrition

Directory of Open Access Journals (Sweden)

Mehmet Akif Özcan

2015-02-01

Full Text Available The use of colloidal silver as an antibiotic was becoming widespread until the 1940s. However, with the discovery of antibiotics, usage of colloidal silver had been reduced because of being expensive. The fact that bacteria develop resistance to antibiotics lead to prohibiton the usage of antibiotics in poultry diets as growth promoters. Based on these developments reuse of colloidal silver has been raised as an alternative to antibiotics. Without prejudice to the beneficial enzymes, colloidal silver disables certain enzymes needed by bacteria, viruses, yeasts, and fungus resulting in the destruction of these enzymes. It is reported that increase in surface area of nano-particles of silver increase antibacterial activity. The most important limitation on the widespread use of silver nanoparticles as feed additives is uncertainty about the possible toxic effects. In this review, studies for the use of colloidal silver particles in poultry feed were evaluated and tried to seek answer the question “may be a new resource that can be used as an alternative to antibiotics?

Stability of colloidal silver nanoparticles trapped in lipid bilayer: effect of lecithin concentration and applied temperature.

Science.gov (United States)

Barani, Hossein; Montazer, Majid; Braun, Hans-Georg; Dutschk, Victoria

2014-12-01

The use of silver nanoparticle on various substrates has been widespread because of its good antibacterial properties that directly depend on the stability of the silver nanoparticles in a colloidal suspension. In this study, the colloidal solutions of the silver nanoparticles were synthesised by a simple and safe method by using lecithin as a stabilising agent and their stability was examined at various temperatures. The effect of the lecithin concentrations on the stability of the synthesised silver nanoparticles was examined from 25 to 80°C at 5°C intervals, by recording the changes in the UV-vis absorption spectra, the hydrodynamic diameter and the light scattering intensity of the silver nanoparticles. In addition, the morphology of the synthesised silver nanoparticles was investigated with the low-voltage scanning electron microscopy and transmission electron microscopy. The results indicated that increasing temperature caused different changes in the size of the stabilised and the unstabilised silver nanoparticles. The size of the stabilised silver nanoparticles reduced from 38 to 36 nm during increasing temperature, which confirmed good stability.