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Silver hydrosol

Anna Zimoch-Korzycka, Andrzej Jarmoluk
The aim of this study was to design and produce biologically active edible hydrosols, which, when applied to the surface of food products, will protect them from oxidative changes, spoilage and growth of microorganisms. Verification of testing hypothesis and the degree of aim realization were performed by assessing a DPPH radical scavenging activity and microbial reduction of experimental hydrosols on the basis of hydroxypropylmethylcellulose (HPMC), chitosan (CH), lysozyme (L) and nanocolloidal silver (NAg)...
September 2015: Journal of Food Science and Technology
Hassan Korbekandi, Gholamreza Asghari, Susan Sadat Jalayer, Maryam Sadat Jalayer, Maedeh Bandegani
BACKGROUND: The production of nanoparticles using a biosystem is considered green chemistry. Application of plant extracts as a biological process has been proven to be suitable for synthesis of nanoparticles. OBJECTIVES: This study designed in order to evaluate the production of silver nanoparticles using Juglans regia leaf extract and to compare the outcome of different preparation methods of plant extracts (ethanolic extract, boiling water extract and plant powder) for the generation of nanoparticles...
2013: Jundishapur Journal of Natural Pharmaceutical Products
Peiyan Ma, Anliang Chen, Yan Wu, Zhengyi Fu, Wei Kong, Liyuan Che, Ruifang Ma
A cost-effective Ag(I)-bovine serum albumin (BSA) supramolecular hydrosol strategy was utilized to assemble Ag3PO4 nanospheres onto reduced graphene oxide (rGO) sheets. The obtained composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy. Compared with the pure Ag3PO4 crystals and Ag3PO4 particles prepared with Ag(I)-BSA hydrosol as precursor, the Ag3PO4/rGO composites obtained with different content of graphene oxide indicated improved visible-light-driven photocatalysis activity for the decomposition of Rhodamine B aqueous solution...
March 1, 2014: Journal of Colloid and Interface Science
Hassan Korbekandi, Zeynab Ashari, Siavash Iravani, Sajjad Abbasi
Silver nanoparticles are increasingly used in various fields of biotechnology and applications in the medicine. Objectives of this study were optimization of production of silver nanoparticles using biotransformations by Fusarium oxysporum, and a further study on the location of nanoparticles synthesis in this microorganism. The reaction mixture contained the following ingredients (final concentrations): AgNO3 (1-10 mM) as the biotransformation substrate, biomass as the biocatalyst, glucose (560 mM) as the electron donor, and phosphate buffer (pH= 7, 100 mM)...
2013: Iranian Journal of Pharmaceutical Research: IJPR
Ricardo J B Pinto, Adelaide Almeida, Susana C M Fernandes, Carmen S R Freire, Armando J D Silvestre, Carlos Pascoal Neto, Tito Trindade
Silver has been mainly investigated as an antibacterial agent and less as a fungicide in which concerns antimicrobial properties. In this research, the antifungal activity of composite films of pullulan and Ag nanoparticles (NP) against Aspergillus niger was evaluated using standard protocols. These new materials were prepared as transparent cast films (66-74 μm thickness) from Ag hydrosols containing the polysaccharide. Fungal growth inhibition was observed in the presence of such silver nanocomposite films...
March 1, 2013: Colloids and Surfaces. B, Biointerfaces
Nandita Maiti, Susy Thomas, Jasmine A Jacob, Ridhima Chadha, Tulsi Mukherjee, Sudhir Kapoor
Surface-enhanced Raman scattering (SERS) study of tryptophan was carried out in silver hydrosol. The surface adsorption properties of tryptophan were investigated due to its biological importance. Tryptophan is an essential amino acid needed for the normal growth in infants and for nitrogen balance in adults. DFT calculations using B3LYP functional with LANL2DZ basis set was carried out to support the experimental Raman and SERS data. The strong enhancement of 1343 cm(-1) band, assigned to the CO(2) sym. stretching vibration in the SERS spectrum along with a red shift of 63 cm(-1), manifests that chemical mechanism contributes to the SERS activity...
August 15, 2012: Journal of Colloid and Interface Science
Ju Young Yook, Gwang-Ho Choi, Dong Hack Suh
We present a novel and facile method to fabricate the silver nanoparticle (AgNP)-sodium deoxycholate (NaDOC) hybrid hydrogel from the NaDOC-stablized AgNP colloidal hydrosol via the pH-induced self-assembly.
May 21, 2012: Chemical Communications: Chem Comm
Linda Böhmert, Birgit Niemann, Andreas F Thünemann, Alfonso Lampen
Silver nanoparticles are used in a wide range of consumer products such as clothing, cosmetics, household goods, articles of daily use and pesticides. Moreover, the use of a nanoscaled silver hydrosol has been requested in the European Union for even nutritional purposes. However, despite the wide applications of silver nanoparticles, there is a lack of information concerning their impact on human health. In order to investigate the effects of silver nanoparticles on human intestinal cells, we used the Caco-2 cell line and peptide-coated silver nanoparticles with defined colloidal, structural and interfacial properties...
July 2012: Archives of Toxicology
Maurizio Muniz-Miranda, Marco Pagliai, Francesco Muniz-Miranda, Vincenzo Schettino
A SERS investigation combined with ab initio computational analysis involving Car-Parrinello molecular dynamics simulations and Density Functional Theory approach allows fundamental information to be obtained on the behaviour of thiazole in silver aqueous suspension where solvation and chemisorption processes competitively occur.
March 21, 2011: Chemical Communications: Chem Comm
Mohammed Fayaz, C S Tiwary, P T Kalaichelvan, R Venkatesan
Recent advances in nanomaterial have produced a new class of fluorescence labels by conjugating noble metal with biomolecules. The nanometer size metal conjugates are water soluble, biocompatible and provide important advantage over the fluorescence dyes. In this regard we synthesized silver nanoparticles at the size of 2-4 nm using biological route and studied fluorescence property of these nanoparticles. We observe that these silver (Ag(+)) ions when exposed to filtrate of Trichoderma viride are reduced in solution, thereby leading to the formation of an extremely stable silver hydrosol...
January 1, 2010: Colloids and Surfaces. B, Biointerfaces
Marco Pagliai, Maurizio Muniz-Miranda, Gianni Cardini, Vincenzo Schettino
The interactions between oxazole and water or silver nanoparticles in aqueous dispersions have been studied with a computational approach based on ab initio molecular dynamics simulations, with the Car-Parrinello method, and density functional calculations in combination with Raman and surface enhanced Raman scattering (SERS) experiments. The solvation dynamics of oxazole in water allowed for the characterization of the hydrogen bond between water and solute, which has been shown to occur essentially through the nitrogen atom of the heterocyclic molecule...
December 31, 2009: Journal of Physical Chemistry. A
Ondrej Dammer, Blanka Vlcková, Marek Procházka, Jan Sedlácek, Jirí Vohlídal, Jirí Pfleger
The influence of the poly(N-ethyl-2-ethynylpyridinium iodide) (PEEP-I) concentration on the morphology and optical properties of nanocomposite systems prepared by mixing the polymer solution with a hydrosol of ca. 9 nm Ag nanoparticles (NPs) was investigated by a combination of surface plasmon extinction (SPE) measurements, transmission electron microscope (TEM) imaging and surface-enhanced Raman spectroscopy (SERS). The PEEP-I concentration was found to have a strong impact on the assembly of Ag NPs and, consequently, on the optical responses of the composite systems...
July 14, 2009: Physical Chemistry Chemical Physics: PCCP
Sukdeb Pal, Yu Kyung Tak, J Joardar, Wook Kim, Jong Eun Lee, Myun Soo Han, Joon Myong Song
Nanocrystalline Silver-supported activated carbon (AC) was fabricated by directly loading silver nanoparticles into the porous AC matrix from a preformed nanosilver hydrosol. Silver-AC composites were also synthesized using a conventional thermal impregnation method. While XRD calculation indicated the presence of Ag crystallites in nanometer range, silver nanoparticle hydrosol-treated AC having the finest crystallite size CS (< 14.4 nm), SEM images clearly revealed that Ag crystals coalesced significantly with increasing temperature resulting in much larger particle size in thermally impregnated silver-AC composities...
March 2009: Journal of Nanoscience and Nanotechnology
Yun Xiao, Ying-Sing Li, George H Swihart
A silver oxide hydrosol has been prepared by reacting silver nitrate with sodium hydroxide in an aqueous solution. The colloidal particle composition and particle size have been characterized by X-ray diffractometry and transmittance electron microscopy. We have demonstrated that the sol is surface-enhanced Raman scattering active. One major advantage of this sol is the absence of the spectral interference arising from reaction products of the sol formation process. The mechanism of surface-enhanced Raman scattering activity is essentially contributed by the silver particles generated from the photochemical process during the laser excitation...
October 16, 2002: Talanta
M J Angebranndt, J D Winefordner
Surface enhanced Raman spectroscopy (SERS) allows the detection of trace quantities of molecular species adsorbed onto a surface. The potential use of silver colloids as substrates for analytical SERS measurements is demonstrated. Detection limits and other analytical figures of merit for pyridine, p-aminobenzoic acid and p-nitrobenzoic acid are presented.
June 1992: Talanta
J J Laserna, A Berthod, J D Winefordner
No abstract text is available yet for this article.
August 1987: Talanta
Virender K Sharma, Ria A Yngard, Yekaterina Lin
This review presents an overview of silver nanoparticles (Ag NPs) preparation by green synthesis approaches that have advantages over conventional methods involving chemical agents associated with environmental toxicity. Green synthetic methods include mixed-valence polyoxometallates, polysaccharide, Tollens, irradiation, and biological. The mixed-valence polyoxometallates method was carried out in water, an environmentally-friendly solvent. Solutions of AgNO(3) containing glucose and starch in water gave starch-protected Ag NPs, which could be integrated into medical applications...
January 30, 2009: Advances in Colloid and Interface Science
William F Pearman, S Michael Angel, John L Ferry, Sherwood Hall
The rapid detection and quantification of saxitoxin (STX) is reported using surface-enhanced Raman spectroscopy (SERS) with a colloidal hydrosol of silver nanoparticles. Under the conditions of our experiments, the limit of detection (LD) for STX using SERS is 3 nM, with a limit of quantification (LQ) of 20 nM. It is shown that the SERS method is rapid, with spectra being collected in as little as 5 seconds total integration time for a 40 nM STX sample. In order to improve the signal-to-noise ratio, SERS spectra were generally collected with a total integration time of 1 minute (6 accumulations of 10 seconds each), with no need for extensive sample work-up or substrate preparation...
July 2008: Applied Spectroscopy
J Yang, Jim Yang Lee, Heng-Phon Too
The ethanol-mediated phase transfer protocol was extended herein to prepare alkylamine-stabilized nanoparticles of several noble metals by transferring them from aqueous environment into toluene. This method relies on the use of ethanol as a mediator to provide and maintain adequate contact between dodecylamine and metal nanoparticles during the transfer process and involves first mixing the metal hydrosols and an ethanol solution of dodecylamine and then extracting the dodecylamine-stabilized metal nanoparticles into toluene...
April 4, 2007: Analytica Chimica Acta
Alois Bonifacio, Peter H J Keizers, Nico P E Vermeulen, Jan N M Commandeur, Cees Gooijer, Gert van der Zwan
Surface-enhanced resonance Raman scattering (SERRS) from dilute solutions (down to nanomolar concentrations) of human mono-oxygenase CYP2D6 is observed using aqueous dispersions of Ag nanoparticles (hydrosol) coated with self-assembled monolayers (SAMs) of mercaptoalkanoic acids of two different lengths. From a direct comparison with its resonance Raman spectrum in solution, CYP2D6 appears to fully retain its native structure upon adsorption on coated hydrosol through electrostatic interaction, while a structural change in the active site is observed when uncoated citrate-reduced hydrosol is used...
February 13, 2007: Langmuir: the ACS Journal of Surfaces and Colloids
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