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Colloidal silver

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https://www.readbyqxmd.com/read/29331861/synthesis-of-colloidal-silver-nanoparticle-clusters-and-their-application-in-ascorbic-acid-detection-by-sers
#1
Jorge L Cholula-Díaz, Diana Lomelí-Marroquín, Bidhan Pramanick, Alfonso Nieto-Argüello, Luis A Cantú-Castillo, Hyundoo Hwang
Ascorbic acid (vitamin C) has an essential role in the human body mainly due to its antioxidant function. In this work, metallic silver nanoparticle (AgNP) colloids were used in SERS experiments to detect ascorbic acid in aqueous solution. The AgNPs were synthesized by a green method using potato starch as reducing and stabilizing agent, and water as the solvent. The optical properties of the yellowish as-synthesized silver colloids were characterized by UV-vis spectroscopy, in which besides a typical band at 410 nm related to the localized surface plasmon resonance of the silver nanoparticles, a shoulder band around 500 nm, due to silver nanoparticle cluster formation, is presented when relatively higher concentrations of starch are used in the synthesis...
December 29, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/29320928/interaction-of-caffeine-and-sulfadiazine-with-lysozyme-adsorbed-at-colloidal-metal-nanoparticle-interface-influence-on-drug-transport-ability-and-antibacterial-activity
#2
Vikash K Sonu, Imocha Rajkumar, Kaushik Bhattacharjee, S R Joshi, Sivaprasad Mitra
The modulated bioactivity of proteins immobilized on nanoparticle (NP) interfaces is of tremendous interest towards designing better therapeutic and diagnostic tools. In this work, binding behavior and the antibacterial activity of free lysozyme (LYS) as well as its non-covalent assembly with silver (Ag) and gold (Au) colloidal NPs were compared in presence of two model drugs, viz. sulfadiazine (SDZ) and caffeine (CAF). Intrinsic protein fluorescence was found to quench due to the formation drug-protein complex in case of CAF resulting a linear Stern-Volmer (SV) plot with KSV = 1...
January 11, 2018: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/29320233/antibacterial-activities-of-hibiscus-sabdariffa-extracts-and-chemical-sanitizers-directly-on-green-leaves-contaminated-with-foodborne-pathogens
#3
Carlos A Gómez-Aldapa, Esmeralda Rangel-Vargas, Ma Refugio Torres-Vitela, Angélica Villarruel-López, Otilio A Acevedo-Sandoval, Alberto J Gordillo-Martínez, Angélica Godínez-Oviedo, Javier Castro-Rosas
Leafy greens have been associated with foodborne disease outbreaks in different countries. To decrease microbial contamination of leafy greens, chemical agents are commonly used; however, a number of studies have shown these agents to have limited antimicrobial effect against pathogenic bacteria on vegetables. The objective of this study was to compare the antibacterial effect of Hibiscus sabdariffa calyx extracts (water, methanol, acetone, and ethyl acetate), sodium hypochlorite, acetic acid, and colloidal silver against foodborne bacteria on leafy greens...
January 10, 2018: Journal of Food Protection
https://www.readbyqxmd.com/read/29319291/ph-responsive-nanovesicles-with-enhanced-emission-co-assembled-by-ag-i-nanoclusters-and-polyethyleneimine-as-a-superior-sensor-for-al3
#4
Jinglin Shen, Zhi Wang, Di Sun, Congxin Xia, Shiling Yuan, Panpan Sun, Xia Xin
Metal nanoclusters (NCs) have been engineered as a new kind of luminescent material. Whereas, the application of metal NCs in aqueous solution was subjected to great limitations owing to their poor solubility, stability and strong luminescence quenching in a single molecule state. Herein, facile supramolecular self-assembly strategy was carried out to enhance the luminescence of Ag(I) nanoclusters (Ag6-NCs) through multiple electrostatic interactions with polyethyleneimine (PEI). Functional colloid aggregates of Ag6-NCs such as nanospheres and nanovesicles were formed along with the enhanced emission due to the formation of compact ordered self-assemblies, which effectively restrict intramolecular vibration (RIV) of the capping ligands on Ag6-NCs to diminish the non-radiative decay...
January 10, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29299755/immobilization-of-recombinant-human-catalase-on-gold-and-silver-nanoparticles
#5
Agnieszka Małgorzata Pudlarz, Ewa Czechowska, Katarzyna Ranoszek-Soliwoda, Emilia Tomaszewska, Grzegorz Celichowski, Jarosław Grobelny, Janusz Szemraj
Human catalase cDNA was cloned into a pEX-C-His vector. Purified recombinant catalase was immobilized on nanoparticles. Gold and silver nanoparticles were synthesized in a variety of sizes by chemical reduction; no agglomerates or aggregates were observed in any of the colloids during dynamic light scattering or scanning transmission electron microscopy analysis. After immobilization on gold nanoparticles, recombinant catalase activity was found to be lower than that of the same amount of enzyme in aqueous solution...
January 3, 2018: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/29258302/implications-of-pony-lake-fulvic-acid-for-the-aggregation-and-dissolution-of-oppositely-charged-surface-coated-silver-nanoparticles-and-their-ecotoxicological-effects-on-daphnia-magna
#6
YounJung Jung, George Metreveli, Chang-Beom Park, Seungyun Baik, Gabriele E Schaumann
Citrate (Cit) and polyethylenimine (BPEI)-coated silver nanoparticles (AgNPs) were used to understand how the type of capping agents and surface charge affect their colloidal stability, dissolution, and ecotoxicity in the absence/presence of Pony Lake Fulvic Acid (PLFA). In the presence of PLFA, Cit-AgNPs were stabilized, while BPEI-AgNPs were aggregated. The aggregation of BPEI-AgNPs decreased with the time and their stabilizing effect increased at high PLFA concentration. The dissolution also differed between both AgNPs and was influenced by the PLFA concentration...
December 19, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29245785/third-order-nonlinear-optics-in-ag-nanocubes-local-and-nonlocal-optical-responses-as-a-function-of-excitation-wavelength-and-particle-size
#7
E V García Ramírez, S A Sabinas Hernández, D Ramírez Martínez, G Díaz, J A Reyes Esqueda
Colloidal silver nanocubes in solution were analyzed by the Z-scan technique in the resonant and non-resonant regimes. Three different systems with particle sizes of 56, 99 and 215 nm, and concentrations of 0.378, 0.831 and 0.715 mg/mL, respectively, were obtained by the polyol method. Nonlinear excitation of the samples was performed with laser pulses of 26 ps, at a repetition rate of 10 Hz, and using three different wavelenghts (355, 532 and 1064 nm), exciting only the electronic part of the optical nonlinearity, and avoiding induced thermal loading of the samples...
December 11, 2017: Optics Express
https://www.readbyqxmd.com/read/29226922/a-polymyxin-b-silver-nanoparticle-colloidal-system-and-the-application-of-lipopolysaccharide-analysis
#8
Tao Liu, Liqian Gao, Jing Zhao, Ya Cao, Yuguo Tang, Peng Miao
Polymyxin B (PMB) is a small cyclic polycationic lipopeptide, which can be used as an antibiotic drug against Gram-negative bacteria. In this work, the interaction between citrate capped silver nanoparticles (AgNPs) and PMB is studied. Experimental results show that the association constant is extremely high and the binding event leads to a significant variation in the localized surface plasmon resonance (LSPR) of AgNPs. Moreover, the PMB-AgNP colloidal system can be further exploited as a sensitive analytical platform...
December 11, 2017: Analyst
https://www.readbyqxmd.com/read/29223055/structure-elucidation-and-degradation-kinetic-study-of-ofloxacin-using-surface-enhanced-raman-spectroscopy
#9
Marwa R El-Zahry, Bernhard Lendl
A simple, fast and sensitive surface enhanced Raman spectroscopy (SERS) method for quantitative determination of fluoroquinolone antibiotic Ofloxacin (OFX) is presented. Also the stability behavior of OFX was investigated by monitoring the SERS spectra of OFX after various degradation processes. Acidic, basic and oxidative force degradation processes were applied at different time intervals. The forced degradation conditions were conducted and followed using SERS method utilizing silver nanoparticles (Ag NPs) as a SERS substrate...
December 5, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29218583/promising-antibacterial-effects-of-silver-nanoparticle-loaded-tea-tree-oil-nanoemulsion-a-synergistic-combination-against-resistance-threat
#10
Roqya Najafi-Taher, Behnaz Ghaemi, Sharmin Kharazi, Samira Rasoulikoohi, Amir Amani
Highly resistant pathogens may be developed in patients with immune disorders after prolonged exposure to antibiotics, a growing threat worldwide. In order to overcome these problems, this study introduces a new class of engineered nanosystems comprising of tea tree oil nanoemulsion (TTO NE) loaded with Ag nanoparticles (NPs). Silver shows a strong toxicity towards a wide range of microorganisms. Also, TTO NE could be employed as a promising and safe antimicrobial agent for local therapies of bacterial infections...
December 7, 2017: AAPS PharmSciTech
https://www.readbyqxmd.com/read/29204271/genome-sequencing-and-analysis-of-the-first-spontaneous-nanosilver-resistant-bacterium-proteus-mirabilis-strain-scdr1
#11
Amr T M Saeb, Khalid A Al-Rubeaan, Mohamed Abouelhoda, Manojkumar Selvaraju, Hamsa T Tayeb
Background: P. mirabilis is a common uropathogenic bacterium that can cause major complications in patients with long-standing indwelling catheters or patients with urinary tract anomalies. In addition, P. mirabilis is a common cause of chronic osteomyelitis in Diabetic foot ulcer (DFU) patients. We isolated P. mirabilis SCDR1 from a Diabetic ulcer patient. We examined P. mirabilis SCDR1 levels of resistance against Nanosilver colloids, the commercial Nanosilver and silver containing bandages and commonly used antibiotics...
2017: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/29203912/bacterial-resistance-to-silver-nanoparticles-and-how-to-overcome-it
#12
Aleš Panáček, Libor Kvítek, Monika Smékalová, Renata Večeřová, Milan Kolář, Magdalena Röderová, Filip Dyčka, Marek Šebela, Robert Prucek, Ondřej Tomanec, Radek Zbořil
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...
January 2018: Nature Nanotechnology
https://www.readbyqxmd.com/read/29201649/direct-deposition-of-silver-nanoplates-on-quartz-surface-by-sequence-pre-treatment-hydroxylation-and-silanisation
#13
Norhayati Abu Bakar, Muhamad Mat Salleh, Akrajas Ali Umar, Joseph George Shapter
Silver nanoparticles deposited on quartz substrates are widely used as SERS substrates. The nanoparticles can be deposited directly from colloidal solution by dipping technique. However, the adhesion of the particles on the quartz surface is very poor. Normally the substrate is pre-treated with hydroxylation or silanisation process. In this paper, we have demonstrated that the application of the sequence pre-treatment hydroxylation and silanisation have improved the density of silver nanoplates desposited on the quartz surface...
2017: MethodsX
https://www.readbyqxmd.com/read/29178954/the-effectiveness-of-topical-colloidal-silver-in-recalcitrant-chronic-rhinosinusitis-a-randomized-crossover-control-trial
#14
John R Scott, Rohin Krishnan, Brian W Rotenberg, Leigh J Sowerby
BACKGROUND: Recalcitrant chronic rhinosinusitis without polyposis (CRSsP) is a challenging condition to manage as traditional medical therapies and surgery fail to provide satisfactory clinical improvements. Colloidal silver (CS), a widely used naturopathic agent, has recently shown anti-biofilm properties both in vitro and within a rhinosinusitis animal model. To date, no trials involving humans have been published in world literature. The purpose of this study was to assess the efficacy of CS as a topical nasal spray in patients with refractory CRSsP...
November 25, 2017: Journal of Otolaryngology—Head & Neck Surgery
https://www.readbyqxmd.com/read/29155403/phyto-assisted-synthesis-of-bio-functionalised-silver-nanoparticles-and-their-potential-anti-oxidant-anti-microbial-and-wound-healing-activities
#15
Yugal Kishore Mohanta, Kunal Biswas, Sujogya Kumar Panda, Jaya Bandyopadhyay, Debashis De, Rasu Jayabalan, Akshaya Kumar Bastia, Tapan Kumar Mohanta
Bio- synthesis of silver nanoparticles (AgNPs) was made by using the aqueous leaf extract of Ardisia solanacea. Rapid formation of AgNPs was observed from silver nitrate upon treatment with the aqueous extract of A. solanacea leaf. The formation and stability of the AgNPs in the colloidal solution were monitored by UV-visible spectrophotometer. The mean particle diameter of AgNPs was calculated from the DLS with an average size ∼4 nm and ∼65 nm. ATR-FTIR spectroscopy confirmed the presence of alcohols, aldehydes, flavonoids, phenols and nitro compounds in the leaf which act as the stabilizing agent...
December 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/29155397/facile-phyto-mediated-synthesis-of-silver-nanoparticles-using-chinese-winter-jujube-ziziphus-jujuba-mill-cv-dongzao-extract-and-their-antibacterial-catalytic-properties
#16
Chun-Gang Yuan, Can Huo, Bing Gui, Jing-Fu Liu, Yong-Sheng Chen
The aqueous extract of Chinese winter jujube (Ziziphus jujuba Mill. cv. Dongzao) was used as reducing and capping agents for the synthesis of silver nanoparticles (AgNPs) for the first time. The resulting AgNPs were characterised by UV/Visible (UV-Vis) spectroscopy, atomic force microscope, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray and Fourier transform infrared spectroscopy (FTIR). The colloidal solution of AgNPs gave a maximum UV-Vis absorbance at 446 nm...
December 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/29144733/a-mechanism-for-symmetry-breaking-and-shape-control-in-single-crystal-gold-nanorods
#17
Michael J Walsh, Wenming Tong, Hadas Katz-Boon, Paul Mulvaney, Joanne Etheridge, Alison M Funston
The phenomenon of symmetry breaking-in which the order of symmetry of a system is reduced despite manifest higher-order symmetry in the underlying fundamental laws-is pervasive throughout science and nature, playing a critical role in fields ranging from particle physics and quantum theory to cosmology and general relativity. For the growth of crystals, symmetry breaking is the crucial step required to generate a macroscopic shape that has fewer symmetry elements than the unit cell and/or seed crystal from which it grew...
November 16, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29132426/comment-on-a-re-assessment-of-the-safety-of-silver-in-household-water-treatment-rapid-systematic-review-of-mammalian-in-vivo-genotoxicity-studies
#18
EDITORIAL
Daniele Lantagne, Justine Rayner, Anjuliee Mittelman, Kurt Pennell
We wish to thank Fewtrell, Majuru, and Hunter for their article highlighting genotoxic risks associated with the use of particulate silver for primary drinking water treatment. The recent promotion of colloidal silver products for household water treatment in developing countries is problematic due to previously identified concerns regarding manufacturing quality and questionable advertising practices, as well as the low efficiency of silver nanoparticles to treat bacteria, viruses, and protozoa in source waters...
November 13, 2017: Environmental Health: a Global Access Science Source
https://www.readbyqxmd.com/read/29120086/how-effective-is-plasmonic-enhancement-of-colloidal-quantum-dots-for-color-conversion-light-emitting-devices
#19
Hyun Chul Park, Isnaeni, Suhyun Gong, Yong-Hoon Cho
Enhancing the fluorescence intensity of colloidal quantum dots (QDs) in case of color-conversion type QD light-emitting devices (LEDs) is very significant due to the large loss of QDs and their quantum yields during fabrication processes, such as patterning and spin-coating, and can therefore improve cost-effectiveness. Understanding the enhancement process is crucial for the design of metallic nanostructure substrates for enhancing the fluorescence of colloidal QDs. In this work, improved color conversion of colloidal green and red QDs coupled with aluminum (Al) and silver (Ag) nanodisk (ND) arrays designed by in-depth systematic finite-difference time domain simulations of excitation, spontaneous emission, and quantum efficiency enhancement is reported...
November 9, 2017: Small
https://www.readbyqxmd.com/read/29111869/biosynthesized-colloidal-silver-and-gold-nanoparticles-as-emerging-leishmanicidal-agents-an-insight
#20
Muhammad Ovais, Akhtar Nadhman, Ali Talha Khalil, Abida Raza, Fazli Khuda, Muhammad Farhan Sohail, Nazar Ul Islam, Hafiz Shoaib Sarwar, Gul Shahnaz, Irshad Ahmad, Muthupandian Saravanan, Zabta Khan Shinwari
Many recent key innovations in nanotechnology have greatly fascinated scientists to explore new avenues in treatment and diagnosis of emerging diseases. Due to extensive utilization of metallic nanoparticles (NPs) in diverse biomedical applications, scientists are looking forward to green synthesis of NPs as safer, simple, fast, and low-cost method over chemical and physical methods. Due to enriched phytochemistry, no need for maintenance and ready availability, plants are preferred for green synthesis of silver (AgNPs) and gold NPs (AuNPs)...
November 7, 2017: Nanomedicine
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