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Colloidal silver

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https://www.readbyqxmd.com/read/28530184/green-synthesis-of-silver-nanoparticles-using-mentha-pulegium-and-investigation-of-their-antibacterial-antifungal-and-anticancer-activity
#1
Ali Hamad Abd Kelkawi, Abolghasem Abbasi Kajani, Abdol-Khalegh Bordbar
A simple and eco-friendly method for efficient synthesis of stable colloidal silver nanoparticles (AgNPs) using Mentha pulegium extracts is described. A series of reactions was conducted using different types and concentrations of plant extract as well as metal ions to optimize the reaction conditions. AgNPs were characterized by using UV-vis spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering, zetasizer, energy-dispersive X-ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR)...
June 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28528626/colloid-particle-formulations-for-antimicrobial-applications
#2
REVIEW
Ahmed F Halbus, Tommy S Horozov, Vesselin N Paunov
Colloidal particles are being extensively studied in various antimicrobial applications due to their small size to volume ratio and ability to exhibit a wide spectrum of antibacterial, antifungal, antialgal and antiviral action. The present review focuses on various nanoparticles (NPs) of inorganic, organic and hybrid materials, and discusses some of the methods for their preparation as well as mechanisms of their antimicrobial action. We consider the antimicrobial applications of metal oxide nanoparticles (ZnO, MgO, CuO, Cu2O, Al2O3, TiO2, CeO2 and Y2O3), metal nanoparticles (NPs), such as copper, silver and gold, metal hydroxide NPs such as Mg(OH)2 as well as hybrid NPs made from biodegradable materials, such as chitosan, lignin and dextran, loaded with other antimicrobial agents...
May 12, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28511013/reversible-tunable-electric-field-driven-assembly-of-silver-nanocrystal-superlattices
#3
Yixuan Yu, Dian Yu, Christine A Orme
Nanocrystal superlattices are typically fabricated by either solvent evaporation or destabilization methods that require long time periods to generate highly ordered structures. In this paper, we report, for the first time, the use of electric fields to reversibly drive nanocrystals assembly into superlattices, without changing solvent volume or composition, and show that this method only takes 20 min to produce polyhedral colloidal crystals, which would otherwise need days or weeks. This method offers a way to control the lattice constants and degree of preferential orientation for superlattices, and can suppress the uniaxial superlattice contraction associated with solvent evaporation...
May 16, 2017: Nano Letters
https://www.readbyqxmd.com/read/28501158/poly-vinyl-alcohol-capped-silver-nanoparticles-for-antioxidant-assay-based-on-seed-mediated-nanoparticle-growth
#4
Saowapak Teerasong, Amornrassamee Jinnarak, Sumonmarn Chaneam, Prapin Wilairat, Duangjai Nacapricha
A simple and rapid method for measurement of total antioxidant capacity (TAC) was developed. In this work, gallic acid was used as the antioxidant standard. Poly(vinyl alcohol) embedded silver nanoparticles (PVA-AgNPs) were employed as a colorimetric sensor. The detection principle was based on the seed-mediated nanoparticle growth technique. The PVA-AgNPs act as a catalyst in the reduction of Ag(+) by gallic acid by providing nucleation seeds. Ag(+) was reduced to Ag° and accumulated on the PVA-AgNP surface, leading to an increase in the size of particles...
August 1, 2017: Talanta
https://www.readbyqxmd.com/read/28493638/chemically-controlled-spatiotemporal-oscillations-of-colloidal-assemblies
#5
Alicia Altemose, Maria A Sánchez-Farrán, Wentao Duan, Steve Schulz, Ali Borhan, Vincent H Crespi, Ayusman Sen
We report an autonomous oscillatory micromotor system in which active colloidal particles form clusters whose size changes periodically. The system consists of an aqueous suspension of silver orthophosphate microparticles under UV illumination, in the presence of varying concentrations of hydrogen peroxide. The colloid particles oscillate between clustering and dispersion. After a cluster oscillation initiates, the oscillatory wave propagates to nearby clusters and eventually all the clusters start oscillating in phase-shifted synchrony...
May 11, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28476988/plants-used-in-folkloric-medicine-of-iran-are-exquisite-bio-resources-in-production-of-silver-nanoparticles
#6
Mohadeseh Hassani Sadi, Gholam Hosein Shahidi Bonjar
This study reports screening of 102 Iranian medicinal plant species belonging to 49 families for the biosynthesis of colloidal silver nanoparticles (AgNPs). Among tested plants, 37 species in 19 plant families are new bio-resources in this regard. Water extracts of macerated plant parts are used in this survey. Six of the bioactive plants are selected for further analysis. They produced amorphous spherical 40-70 nm AgNPs. Biosynthesised colloidal AgNPs are characterised by UV-visible spectroscopy, transmission electron microscopy and scanning electron microscopy...
April 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28476089/antitumor-activity-of-alloy-and-core-shell-type-bimetallic-agau-nanoparticles
#7
Igor Shmarakov, Iuliia Mukha, Nadiia Vityuk, Vira Borschovetska, Nelya Zhyshchynska, Galyna Grodzyuk, Anna Eremenko
Nanoparticles (NPs) of noble metals, namely gold and silver, remain promising anticancer agents capable of enhancing current surgery- and chemotherapeutic-based approaches in cancer treatment. Bimetallic AgAu composition can be used as a more effective agent due to the synergetic effect. Among the physicochemical parameters affecting gold and silver nanoparticle biological activity, a primary concern relates to their size, shape, composition, charge, etc. However, the impact of metal components/composition as well as metal topological distribution within NPs is incompletely characterized and remains to be further elucidated and clarified...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28475520/mucocutaneous-hyperpigmentation-in-a-patient-with-a-history-of-both-minocycline-and-silver-ingestion
#8
Angel Fernandez-Flores, Thao Nguyen, David S Cassarino
Minocycline is a derivative of tetracycline. It has been widely used in dermatology for the treatment of acne and rosacea. One of its adverse effects is pigmentation of various body tissues. Clinically, 3 main distinct types of hyperpigmentation by minocycline have been distinguished: type I, with blue-gray to black pigment on the face in areas of scarring or inflammation; type II, with blue-gray pigment on normal skin of the legs, forearms and on the shins; and type III, with a diffuse muddy-brown discoloration in areas of sun exposure...
April 27, 2017: American Journal of Dermatopathology
https://www.readbyqxmd.com/read/28462937/ion-specific-ice-recrystallization-provides-a-facile-approach-for-the-fabrication-of-porous-materials
#9
Shuwang Wu, Chongqin Zhu, Zhiyuan He, Han Xue, Qingrui Fan, Yanlin Song, Joseph S Francisco, Xiao Cheng Zeng, Jianjun Wang
Ice recrystallization is of great importance to both fundamental research and practical applications, however understanding and controlling ice recrystallization processes remains challenging. Here, we report the discovery of an ion-specific effect on ice recrystallization. By simply changing the initial type and concentration of ions in an aqueous solution, the size of ice grains after recrystallization can be tuned from 27.4±4.1 to 277.5±30.9 μm. Molecular dynamics simulations show that the ability of the ion to be incorporated into the ice phase plays a key role in the ultimate size of the ice grains after recrystallization...
May 2, 2017: Nature Communications
https://www.readbyqxmd.com/read/28445028/enhanced-electrocatalytic-activity-of-ethanol-oxidation-reaction-on-palladium-silver-nanoparticles-via-removable-surface-ligands
#10
Hucheng Zhang, Yingying Shang, Jing Zhao, Jianji Wang
This work developed a facile colloidal route to synthesize BH4(-)-capped PdxAgy nanoparticles (NPs) in water using the reducing ionic liquids of [Cnmim]BH4, and the resulting NPs were prone to form the nanocomposites with [amim](+)-modified reduced graphene (RG). The removal of the metal-free inorganic ions of BH4(-) can create the profoundly exposed interfaces on the PdxAgy NPs during the electrooxidation, and favor the ethanol oxidation reaction (EOR) in lowering energy barrier. The counterions of [Cnmim](+) can gather ethanol, OH(-) ions, and the reaction intermediates on catalysts, and synergistically interact with RG to facilitate the charge transfer in nanocomposites...
May 2, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28436147/rapid-detection-of-six-phosphodiesterase-type-5-enzyme-inhibitors-in-health-care-products-using-thin-layer-chromatography-and-surface-enhanced-raman-spectroscopy-combined-with-bp-neural-network
#11
Xiaopeng Hu, Guozhen Fang, Ailing Han, Yunpeng Fu, Rui Tong, Shuo Wang
A novel facile method for the detection of the phosphodiesterase type 5 enzyme inhibitors added illegally into health products was established using thin-layer chromatography and surface enhanced Raman spectroscopy combined with BP neural network. When the detecting conditions were optimized in detail, a repetitive adding procedure of silver colloids with the total amount keeping constant was used to improve the enhancement effect of surface enhanced Raman spectroscopy. According to the main Raman peaks and the retention factor of analyte, the data predictive model was established...
April 24, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28415554/phytosynthesis-of-silver-nanoparticles-using-aqueous-leaf-extracts-of-lippia-citriodora-antimicrobial-larvicidal-and-photocatalytic-evaluations
#12
Elias E Elemike, Damian C Onwudiwe, Anthony C Ekennia, Richard C Ehiri, Nnaemeka J Nnaji
Nanoscience and nanotechnology represent new and enabling platforms that promise to provide broad range of novel and improved technologies for environmental, biological and other scientific applications. This study reports the synthesis of silver nanoparticles mediated by aqueous leaf extract of Lippia citriodora at two different temperatures of 50°C and 90°C. The synthesis of colloidal silver nanoparticles (AgNPs) was monitored by the use of UV-visible spectroscopy at different temperatures and time intervals...
June 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28409425/instant-green-synthesis-of-silver-based-herbo-metallic-colloidal-nanosuspension-in-terminalia-bellirica-fruit-aqueous-extract-for-catalytic-and-antibacterial-applications
#13
Sandeep Patil, Gunjan Chaudhari, Jayasinh Paradeshi, Raghunath Mahajan, Bhushan L Chaudhari
In the present study, microwave-assisted, optimized, instant, Terminalia bellirica fruit extract-mediated green synthesis of colloidal silver nanoparticles (AgNPs) has been reported. The synthesized AgNPs were characterized by UV-Vis spectroscopy, FTIR, Zetasizer, FESEM, EDX and XRD. The characteristic surface plasmon peak of reaction mixture at 406 nm confirmed the synthesis of AgNPs. The FTIR studies confirmed phytoconstituents were responsible for the synthesis and stability of AgNPs. The FESEM, EDX and XRD analysis revealed the presence of spherical silver nanoparticles of mean diameter ≤20...
May 2017: 3 Biotech
https://www.readbyqxmd.com/read/28408822/negatively-charged-silver-nanoparticles-with-potent-antibacterial-activity-and-reduced-toxicity-for-pharmaceutical-preparations
#14
Lucia Salvioni, Elisabetta Galbiati, Veronica Collico, Giulia Alessio, Svetlana Avvakumova, Fabio Corsi, Paolo Tortora, Davide Prosperi, Miriam Colombo
BACKGROUND: The discovery of new solutions with antibacterial activity as efficient and safe alternatives to common preservatives (such as parabens) and to combat emerging infections and drug-resistant bacterial pathogens is highly expected in cosmetics and pharmaceutics. Colloidal silver nanoparticles (NPs) are attracting interest as novel effective antimicrobial agents for the prevention of several infectious diseases. METHODS: Water-soluble, negatively charged silver nanoparticles (AgNPs) were synthesized by reduction with citric and tannic acid and characterized by transmission electron microscopy, dynamic light scattering, zeta potential, differential centrifuge sedimentation, and ultraviolet-visible spectroscopy...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28383922/surface-enhanced-resonance-hyper-raman-scattering-elucidates-the-molecular-orientation-of-rhodamine-6g-on-silver-colloids
#15
Hubert K Turley, Zhongwei Hu, Lasse Jensen, Jon P Camden
Herein, we utilize surface-enhanced hyper-Raman scattering (SEHRS) under resonance conditions to probe the adsorbate geometry of rhodamine 6G (R6G) on silver colloids. Our results show resonance SEHRS is highly sensitive to molecular orientation due to non-Condon effects, which do not appear in its linear counterpart surface-enhanced Raman scattering. Comparisons between simulated and measured SEHRS spectra reveal R6G adsorbs mostly perpendicular to the nanoparticle surface along the ethylamine groups with the xanthene ring oriented edgewise...
April 20, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28381077/the-effect-of-silver-and-copper-nanoparticles-on-the-wheat-pseudocercosporella-herpotrichoides-pathosystem
#16
V N Belava, O O Panyuta, G M Yakovleva, Y M Pysmenna, M V Volkogon
The paper covers the study of the effects of silver (Ag) and copper (Cu) nanoparticles on wheat-Pseudocercosporella herpotrichoides pathosystem in general and, separately, on their interaction both with the plant and with the pathogen. Plants, treated with nonionic colloidal solutions of biogenic metal nanoparticles of Ag and Cu, have taken seed treatment as stress and have demonstrated the same changes in the dynamic patterns of thiobarbituric acid reactive substances (TBARS) content as a seedling infection or in its combination with a nanoparticle treatment...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28379105/the-ability-of-a-colloidal-silver-gel-wound-dressing-to-kill-bacteria-in-vitro-and-in-vivo
#17
P L Tran, E Huynh, A N Hamood, A de Souza, D Mehta, K W Moeller, C D Moeller, M Morgan, T W Reid
OBJECTIVE: Inhibiting bacterial biofilms is of major significance for proper wound healing. The choice of the dressing material plays a key role, as bacteria can live in dressings and keep reinfecting the wound. This study examines the effectiveness of a colloidal silver gel (Ag-gel) wound dressing in inhibiting the growth of bacteria in a mouse wound model. METHOD: Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii and two different meticillin-resistant Staphylococcus aureus (MRSA) strains were examined...
April 1, 2017: Journal of Wound Care
https://www.readbyqxmd.com/read/28335201/size-and-shape-dependent-antibacterial-studies-of-silver-nanoparticles-synthesized-by-wet-chemical-routes
#18
Muhammad Akram Raza, Zakia Kanwal, Anum Rauf, Anjum Nasim Sabri, Saira Riaz, Shahzad Naseem
Silver nanoparticles (AgNPs) of different shapes and sizes were prepared by solution-based chemical reduction routes. Silver nitrate was used as a precursor, tri-sodium citrate (TSC) and sodium borohydride as reducing agents, while polyvinylpyrrolidone (PVP) was used as a stabilizing agent. The morphology, size, and structural properties of obtained nanoparticles were characterized by scanning electron microscopy (SEM), UV-visible spectroscopy (UV-VIS), and X-ray diffraction (XRD) techniques. Spherical AgNPs, as depicted by SEM, were found to have diameters in the range of 15 to 90 nm while lengths of the edges of the triangular particles were about 150 nm...
April 15, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28329568/localized-cutaneous-argyria-report-of-two-patients-and-literature-review
#19
Bryce David Beutler, Robert A Lee, Philip R Cohen
BackgroundLocalized cutaneous argyria is a rare skin condition caused by direct contact with silver or silver particles. It presents as asymptomatic gray or blue-gray macules that appear similar to blue nevi. Histologic features include brown-colored or black-colored silver granules in the basement membrane and dermis, most commonly surrounding eccrine glands, elastic fibers, and collagen fibrils. The condition is most frequently observed in individuals who are regularly exposed to small silver particles, such as silversmiths and welders...
November 15, 2016: Dermatology Online Journal
https://www.readbyqxmd.com/read/28235364/synthesis-and-examination-of-nanocomposites-based-on-poly-2-hydroxyethyl-methacrylate-for-medicinal-use
#20
Olena S Kukolevska, Igor I Gerashchenko, Mykola V Borysenko, Evgenii M Pakhlov, Michal Machovsky, Tetyana I Yushchenko
Preparation of poly(2-hydroxyethyl methacrylate) (PHEMA) based nanocomposites using different approaches such as synthesis with water as the porogen, filling of polymer matrix by silica and formation of interpenetrating polymer networks with polyurethane was demonstrated. Incorporation of various biologically active compounds (BAC) such as metronidazole, decamethoxin, zinc sulphate, silver nitrate or amino acids glycine and tryptophan into nanocomposites was achieved. BAC were introduced into the polymer matrix either (1) directly, or (2) with a solution of colloidal silica, or (3) through immobilization on silica (sol-densil)...
December 2017: Nanoscale Research Letters
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