keyword
MENU ▼
Read by QxMD icon Read
search

Colloidal silver

keyword
https://www.readbyqxmd.com/read/28217797/poly-vinyl-alcohol-as-a-water-protecting-agent-for-silver-nanoparticles-the-role-of-polymer-size-and-structure
#1
Alexander Kyrychenko, Dmitry A Pasko, Oleg N Kalugin
Chemical modification of silver nanoparticles (AgNPs) with a stabilizing agent, such as poly(vinyl alcohol) (PVA), plays an important role in shape-controlled seeded-growth and colloidal stability. However, theoretical aspects of the stabilizing mechanism of PVA are still poorly understood. To gain a better understanding of the role of PVA in water protecting effects for silver nanoparticles, we developed an atomistic model of a AgNP grafted with single-chain PVA of various lengths. Our model, designed for classical molecular dynamics (MD) simulations, approximates the AgNP as a quasi-spherical silver nanocrystal with 3...
February 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28199144/attachment-of-13-types-of-foodborne-bacteria-to-jalape%C3%A3-o-and-serrano-peppers-and-antibacterial-effect-of-roselle-calyx-extracts-sodium-hypochlorite-colloidal-silver-and-acetic-acid-against-these-foodborne-bacteria-on-peppers
#2
Esmeralda Rangel-Vargas, Carlos A Gómez-Aldapa, Reyna N Falfan-Cortes, María L Rodríguez-Marín, Angélica Godínez-Oviedo, Otilio A Acevedo-Sandoval, Javier Castro-Rosas
Chili peppers are a very important crop in Mexico. However, these peppers have been associated with Salmonella infection outbreaks in the United States, and Salmonella and diarrheagenic Escherichia coli pathotypes have been isolated from jalapeño and serrano peppers in Mexico. To decrease microbial contamination of fruits and vegetables, chemical agents are commonly used; however, chemical agents used to eliminate pathogenic bacteria on vegetables have a limited antimicrobial effect. Roselle ( Hibiscus sabdariffa ) calyces have been reported to have an antimicrobial effect on pathogenic bacteria...
February 15, 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/28198355/in-situ-spectroscopy-of-ligand-exchange-reactions-at-the-surface-of-colloidal-gold-and-silver-nanoparticles
#3
Rebecca Dinkel, Wolfgang Peukert, Björn Braunschweig
Gold and silver nanoparticles with their tunable optical and electronic properties are of great interest for a wide range of applications. Often the ligands at the surface of the nanoparticles have to be exchanged in a second step after particle formation in order to obtain a desired surface functionalization. For many techniques, this process is not accessible in situ. In this review, we present second-harmonic scattering (SHS) as an inherently surface sensitive and label-free optical technique to probe the ligand exchange at the surface of colloidal gold and silver nanoparticles in situ and in real time...
February 15, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28192905/extracting-metallic-nanoparticles-from-soils-for-quantitative-analysis-method-development-using-engineered-silver-nanoparticles-and-sp-icp-ms
#4
D M Schwertfeger, Jessica R Velicogna, Alexander H Jesmer, Selin Saatcioglu, Heather McShane, Richard P Scroggins, Juliska I Princz
The lack of an efficient and standardized method to disperse soil particles and quantitatively subsample the nanoparticulate fraction for characterization analyses is hindering progress in assessing the fate and toxicity of metallic engineered nanomaterials in the soil environment. This study investigates various soil extraction and extract preparation techniques for their ability to remove nanoparticulate Ag from a field soil amended with biosolids contaminated with engineered silver nanoparticles (AgNPs), while presenting a suitable suspension for quantitative single-particle inductively coupled plasma mass spectroscopy (SP-ICP-MS) analysis...
January 30, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28191921/design-of-hybrid-nanostructural-arrays-to-manipulate-sers-active-substrates-by-nanosphere-lithography
#5
Xiaoyu Zhao, Jiahong Wen, Mengning Zhang, Dunhui Wang, Yaxin Wang, Lei Chen, Yongjun Zhang, Jinghai Yang, Youwei Du
An easy-handling and low-cost method is utilized to controllably fabricate nanopattern arrays as the surface-enhanced Raman scattering (SERS) active substrates with high density of SERS-active areas (hot spots). A hybrid silver array of nanocaps and nanotriangles are prepared by combining magnetron sputtering and plasma etching. By adjusting the etching time of polystyrene (PS) colloid spheres array in silver nanobowls, the morphology of the arrays can be easily manipulated to control the formation and distribution of hot spots...
February 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28186767/size-control-of-silver-core-silica-shell-nanoparticles-fabricated-by-laser-ablation-assisted-chemical-reduction
#6
Victor A Ermakov, Ernesto Jimenez-Villar, José Maria Clemente da Silva Filho, Emre Yassitepe, Naga Vishnu Vardhan Mogili, Fernando Iikawa, Gilberto Fernandes de Sá, Carlos Lenz Cesar, Francisco Chagas Marques
Aqueous colloidal silver nanoparticles have substantial potential in biological application as markers and antibacterial agents and in surface-enhanced Raman spectroscopy applications. A simple method of fabrication and encapsulation into an inert shell is of great importance today to make their use ubiquitous. Here we show that colloids of silver-core/silica-shell nanoparticles can be easily fabricated by a laser-ablation-assisted chemical reduction method and their sizes can be tuned in the range of 2.5 to 6...
February 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28177604/green-in-situ-synthesis-of-clean-3d-chestnutlike-ag-wo3-x-nanostructures-for-highly-efficient-recyclable-and-sensitive-sers-sensing
#7
Jian Huang, Dayan Ma, Feng Chen, Dongzhen Chen, Min Bai, Kewei Xu, Yongxi Zhao
Surface-enhanced Raman scattering (SERS) has proven to be an effective technique for identifying and providing fingerprint structural information on various analytes in low concentration. However, this analytical technique has been plagued by the ubiquitous presence of organic contaminants on roughened SERS substrate surfaces, which not only often result in poorer detection sensitivity but also significantly affect the reproducibility and accuracy of SERS analysis. Herein, we developed a clean, stable, and recyclable three-dimensional (3D) chestnutlike Ag/WO3-x (0 < x < 0...
February 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28177254/experimental-and-numerical-investigations-of-silver-nanoparticle-transport-under-variable-flow-and-ionic-strength-in-soil
#8
Joanna Makselon, Dan Zhou, Irina Engelhardt, Diederik Jacques, Erwin Klumpp
Unsaturated column experiments were conducted with an undisturbed loamy sand soil to investigate the influence of flow interruption (FI) and ionic strength (IS) on the transport and retention of surfactant-stabilized silver nanoparticles (AgNP) and the results were compared to those obtained under continuous flow conditions. AgNP concentrations for breakthrough curves (BTCs) and retention profiles (RPs) were analyzed by ICP-MS. Experimental results were simulated by the numerical code HP1 (Hydrus-PhreeqC) with the DLVO theory, extended colloid filtration theory and colloid release model...
February 8, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28159292/determination-of-histamine-in-fish-by-surface-enhanced-raman-spectroscopy-using-silver-colloid-sers-substrates
#9
Tibor Janči, Davor Valinger, Jasenka Gajdoš Kljusurić, Lara Mikac, Sanja Vidaček, Mile Ivanda
This study was focused on development of a rapid and sensitive method for histamine determination in fish based on Surface Enhanced Raman Spectroscopy (SERS) using simple and widely available silver colloid SERS substrate. Extraction of histamine with 0.4M perchloric acid and purification with 1-butanol significantly shortened sample preparation (30min) and provided clear SERS spectra with characteristic Raman bands of histamine. Principal component analysis effectively distinguished SERS spectra of fish samples with different histamine content...
June 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28159107/chlorine-triggered-de-alloying-of-auag-carbon-nanodots-towards-fabrication-of-a-dual-signalling-assay-combining-the-plasmonic-property-of-bimetallic-alloy-nanoparticles-and-photoluminescence-of-carbon-nanodots
#10
Zahra Mohammadpour, Afsaneh Safavi, Seyyed Hossein Abdollahi
Integration of Au-Ag alloy and fluorescent carbon nanodots (C-dots) into a single platform resulted in a new dual sensing assay for chlorine. Selective etching of Ag from AuAg@C-dots was transformed into: (i) colorimetric signal by surface plasmon resonance (SPR) tuning of the alloy and (ii) fluorimetric signal by perturbation of fluorescence energy transfer between C-dots and alloy nanoparticles. Fast oxidizing of silver atoms incorporated in the bimetallic structure induced by chlorine resulted in selective de-alloying of bimetallic hybrid nanoparticles and an intense visible change of the colloidal dispersion color...
March 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28126610/vortex-assisted-layer-by-layer-assembly-of-silver-nanowire-thin-films-for-flexible-and-transparent-conductive-electrodes
#11
Changho Kim, Hyojin An, Arum Jung, Bongjun Yeom
Silver nanowires (AgNWs) have drawn much attention as potential candidates to replace conventional transparent conductive materials such as indium tin oxide (ITO). AgNWs have advantages over ITO with respect to cost and ease of fabrication, and can be used in flexible electrodes. However, the preparation of homogeneous films from the AgNW colloidal suspension is still a challenge mainly because of the coagulation and sedimentation of AgNWs in aqueous media. In this study, uniform transparent conductive films were prepared by using AgNWs paired with poly(allylamine hydrochloride) (PAH) via the vortex-assisted layer-by-layer (VA-LbL) assembly method...
January 17, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28126339/fabrication-of-silica-coated-gold-nanorods-and-investigation-of-their-property-of-photothermal-conversion
#12
Tomoya Inose, Takahiro Oikawa, Kyosuke Shibuya, Masayuki Tokunaga, Keiichiro Hatoyama, Kouichi Nakashima, Takashi Kamei, Kohsuke Gonda, Yoshio Kobayashi
This study described the preparation of silica-coated Au nanorods (AuNR/SiO2) in a colloidal solution, assessed their property of photothermal conversion, and investigated their ability to kill cancer cells using photothermal conversion. Au-seed nanoparticles were produced by reducing hydrogen tetrachloroaurate (HAuCl4) with sodium borohydride (NaBH4) in aqueous n-hexadecyltrimethylammonium bromide (CTAB) solution. AuNRs were then fabricated by reducing HAuCl4 and silver nitrate (AgNO3) with l-ascorbic acid in the aqueous CTAB solution in the presence of Au-seed nanoparticles...
January 23, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28121071/colloidal-gold-nanoclusters-spiked-silica-fillers-in-mixed-matrix-coatings-simultaneous-detection-and-inhibition-of-healthcare-associated-infections
#13
Shahad K Alsaiari, Mohammed A Hammami, Jonas G Croissant, Haneen W Omar, Pradeep Neelakanda, Tahir Yapici, Klaus-Viktor Peinemann, Niveen M Khashab
Healthcare-associated infections (HAIs) are the infections that patients get while receiving medical treatment in a medical facility with bacterial HAIs being the most common. Silver and gold nanoparticles (NPs) have been successfully employed as antibacterial motifs; however, NPs leaching in addition to poor dispersion and overall reproducibility are major hurdles to further product development. In this study, the authors design and fabricate a smart antibacterial mixed-matrix membrane coating comprising colloidal lysozyme-templated gold nanoclusters as nanofillers in poly(ethylene oxide)/poly(butylene terephthalate) amphiphilic polymer matrix...
January 25, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28109747/silver-nanoparticles-induce-hormesis-in-a549-human-epithelial-cells
#14
Mireille M J P E Sthijns, Waluree Thongkam, Catrin Albrecht, Bryan Hellack, Aalt Bast, Guido R M M Haenen, Roel P F Schins
Despite the gaps in our knowledge on the toxicity of silver nanoparticles (AgNPs), the application of these materials is fast expanding, from medicine, to food as well as the use in consumer products. It has been reported that prolonged exposure might make cells more resistant to AgNPs. This prompted us to investigate if AgNPs may give rise to a hormetic response. Two types of AgNPs were used, i.e. colloidal AgNPs and an AgNP powder. For both types of nanosilver it was found that a low dose pretreatment of A549 human epithelial cells with AgNPs induced protection against a toxic dose of AgNPs and acrolein...
January 18, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/28075572/effect-of-protein-corona-on-silver-nanoparticle-stabilization-and-ion-release-kinetics-in-artificial-seawater
#15
Maja Levak, Petra Burić, Maja Dutour Sikirić, Darija Domazet Jurašin, Nevenka Mikac, Niko Bačić, Roland Drexel, Florian Meier, Željko Jakšić, Daniel M Lyons
In parallel with the growing use of nanoparticle-containing products, their release into the environment over the coming years is expected to increase significantly. With many large population centers located in near-coastal areas, and increasing evidence that various nanoparticles may be toxic to a range of organisms, biota in estuarine and coastal waters may be particularly vulnerable. While size effects may be important in cases, silver nanoparticles have been found to be toxic in large part due to their release of silver ions...
January 30, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28070779/hydrolytic-activity-of-esterase-antibody-complexes-retained-within-gel-capsules-after-complex-isolation
#16
Youji Shimazaki, Rino Miyatsuka
Delipidation in biological samples is important for some diagnostic tests and protein analyses. Lipids in the samples can be hydrolyzed by native esterases (ESs) within gel capsules after ES, and ES-antibody complexes are specifically trapped, extracted, and separated. Acrylamide and agarose gel capsules containing complexes of ES antibody were produced after the complexes were extracted using protein A-immobilized membranes, separated by non-denaturing electrophoresis, and stained by colloidal silver using glucose as a reductant...
January 9, 2017: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/28056445/stabilizer-free-silver-nanoparticles-as-efficient-catalysts-for-electrochemical-reduction-of-oxygen
#17
Alexey Treshchalov, Heiki Erikson, Laurits Puust, Sergey Tsarenko, Rando Saar, Alexander Vanetsev, Kaido Tammeveski, Ilmo Sildos
In this work we demonstrated the potential of the He+5% H2+1% N2 plasma jet treatment for the synthesis of surfactant-free silver nanoparticles (Ag NPs) with narrow size distribution. The obtained colloidal solutions of electrostatically stabilized Ag NPs do not show any agglomeration for several months. Apart from an atomic thin oxide layer and the relatively weakly bound OH(-) ions, the surface of Ag NPs can be considered as stabilizer-free. The surface charge (characterized by the zeta potential) of Ag NPs in solution was measured by electrophoretic light scattering technique...
April 1, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28054120/assessment-of-human-telomeric-g-quadruplex-structures-using-surface-enhanced-raman-spectroscopy
#18
Snežana Miljanić, Marina Ratkaj, Marija Matković, Ivo Piantanida, Paola Gratteri, Carla Bazzicalupi
G-Quadruplex (G4) structures of a human telomeric 24-mer (5'-TTAGGGTTAGGGTTAGGGTTAGGG-3') sequence (Tel24) stabilized by sodium and potassium ions have been assessed using surface-enhanced Raman scattering (SERS) spectroscopy. The distinctive SERS spectra of Tel24 in the presence of 100 mM Na(+) and 100 mM K(+) were obtained and the SERS bands characteristic of the antiparallel basket-type and the mixed hybrid (3+1) structures, respectively, were identified and assigned. The influence of the SERS - active substrate on the scattering enhancement was studied using citrate- and chloride-covered silver nanoparticles, in the absence and presence of the aggregating agent (0...
January 4, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28039830/characterization-of-silver-nanoparticle-aggregates-using-single-particle-inductively-coupled-plasma-mass-spectrometry-spicp-ms
#19
Hyun-A Kim, Byung-Tae Lee, So-Young Na, Kyoung-Woong Kim, James F Ranville, Soon-Oh Kim, Eunhye Jo, Ig-Chun Eom
The single particle-inductively coupled plasma-mass spectrometry was applied to characterize the aggregates of AgNPs. was applied to characterize the aggregates of AgNPs. Two sizes of citrate-AgNPs and PVP-AgNPs were used at relatively high and predicted environmental concentrations under various ionic strengths. Citrate-AgNP aggregated with increases in the ionic strength, whereas PVP-AgNPs were sterically stable. The critical coagulation concentrations were 85 mM and 100 mM NaNO3 for 60 nm and 100 nm citrate-AgNPs at 2 mg L(-1) as total Ag obtained by dynamic light scattering (DLS)...
December 19, 2016: Chemosphere
https://www.readbyqxmd.com/read/28038745/embedment-of-silver-into-temperature-and-ph-responsive-microgel-for-the-development-of-smart-textiles-with-simultaneous-moisture-management-and-controlled-antimicrobial-activities
#20
Danaja Štular, Ivan Jerman, Iztok Naglič, Barbara Simončič, Brigita Tomšič
Silver nanoparticles were embedded into a temperature- and pH-responsive microgel based on poly-(N-isopropylacrylamide) and chitosan (PNCS) before or after its application to cotton fabric to create a smart stimuli-responsive textile with simultaneous moisture management and controlled antimicrobial activities. Two different methods of silver embedment into the PNCS microgel using two different forms of silver nanoparticles were studied, i.e., in-situ synthesis of AgCl nanocrystals into PNCS microgel particles that had previously been applied to cotton fabric, as well as the direct incorporation of colloidal silver into the microgel suspension prior to its deposition on cellulose fibres...
March 1, 2017: Carbohydrate Polymers
keyword
keyword
77920
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"