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A much studied oil-soluble surfactant, bis[2-ethylhexyljsulfosuccinate, sodium salt, was ion exchanged into the silver ion form and dissolved into microemulsionsof immiscible polyurethane step monomers. Coating andcuring of these ...
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A much studied oil-soluble surfactant, bis[2-ethylhexyljsulfosuccinate, sodium salt, was ion exchanged into the silver ion form and dissolved into microemulsionsof immiscible polyurethane step monomers. Coating andcuring of these microemulsions produced polyurethanecoatings that exhibit bactericidal activity against representative Gram negative bacteria. After 24 h exposure, 0.006-0.012% weight Ag relative to coating weight (0.0013-0.0025 mu mol Ag/cm~2) results in the three-log reduction in Escherichia coli. A slightly higher level of 0.031% weightAg relative to coating weight (0.006 mu mol Ag/cm~2) killedall of the E. coli after 12 h exposure. Similar results wereobtained for Pseudomonas aeruginosa. Since the doubletail surfactant anion promotes reverse micelle formation in many different kinds of oils and solvents, it appears anexcellent vector for incorporating low and effectiveamounts of silver ion into many industrial, hospital, andhousehold coating formulations.
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This review summarises patents published from 2001 to 2004 on the micro-cidal properties of silver-releasing materials for healthcare and medicine. The anti-inflammatory, re-epitheliasation and antihaemorrhagic properties of the s...
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This review summarises patents published from 2001 to 2004 on the micro-cidal properties of silver-releasing materials for healthcare and medicine. The anti-inflammatory, re-epitheliasation and antihaemorrhagic properties of the silver-releasing materials are also disclosed. A biological evaluation of the antiviral properties of silver tetra-silver tetra-oxide is discussed, but no biological data have been reported to support the claim that silver (1) has antiviral properties, as disclosed by most of the patents.
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The use of an electrochemical reactor operated under different flow conditions to deposit silver from aqueous AgNO3 solutions and tartaric acid as an organic additive on a commercial activated carbon with ultimate bactericidal app...
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The use of an electrochemical reactor operated under different flow conditions to deposit silver from aqueous AgNO3 solutions and tartaric acid as an organic additive on a commercial activated carbon with ultimate bactericidal applications in water purification processes is presented.The characterization of carbon/silver samples was studied by BET,FTIR,X-ray diffraction,XPS,and SEM techniques.The bactericidal activity of the carbon/silver samples was tested on drinking water samples inoculated with E.coli.A reduction of carbon surface area was detected and was caused by increased amounts of silver deposited on carbon samples.Adherent silver deposits were obtained on the carbon/silver samples.X-ray diffraction studies of carbon with electrodeposited silver showed two different preferential deposition planes,[111] and [220].The FTIR results confirm the presence of carboxyl,phenolic,quinone,and ether surface groups.The XPS results suggest the formation of Ag2O and AgO surface species and confirm the reduction of silver to the metallic form.Antimicrobial activity toward E.coli indicated reductions by up to 7 orders of magnitude in the log CFU/mL in just 10 min contact time and for silver contents of 2.47 wt%.
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This work aimed to produce freeze-cast pellets of porous ceramic filters of alumina and kaolinite impregnated with silver nanoparticles and to test the efficiency of bactericidal effects. Silver nanoparticles were characterized by...
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This work aimed to produce freeze-cast pellets of porous ceramic filters of alumina and kaolinite impregnated with silver nanoparticles and to test the efficiency of bactericidal effects. Silver nanoparticles were characterized by average particle size, zeta potential and TEM. After impregnation, leached water was analyzed by graphite furnace atomic absorption spectrometry (GFAAS) that showed an efficiency of more than 99.9% in silver impregnation. From SEM/EDS, it was possible to observe that the pellets have a homogeneous distribution of silver nanoparticles. A halo of inhibition detected by the disc diffusion test shows a strong bactericidal effect of the filters.
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Surface coating of metal nanoparticles is one of the major aspects to be optimized in the design of antimicrobial nanoparticles. The novelty of this work is that antimicrobial derivatives have been used as stabilizers to protect s...
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Surface coating of metal nanoparticles is one of the major aspects to be optimized in the design of antimicrobial nanoparticles. The novelty of this work is that antimicrobial derivatives have been used as stabilizers to protect silver nanoparticles (Ag NPs). Microbicidal activity studies of fabricated cotton textiles coated with these Ag@Antibio were performed. Protective ligand layers of Ag NPs resulted to be a deterministic factor in their antimicrobial activity. The best bactericidal activity was obtained for Fabric TAM (coated with Ag NPs with triarylmethane derivates in surface, Ag@TAMSH), with a bacterial decrease of 3 log units for the S. aureus strain. Intrinsic antibiotic activity and partial positive charge of the TAMSH probably enhanced their antimicrobial effects. Fabric Eu (coated with Ag NPs with eugenol derivates in surface, Ag@EugenolSH) and Fabric FQPEG (coated with Ag NPs embedded in PEG-fluoroquinolone derivatives in surface, Ag@FQPEG) displayed antibacterial activity for both Staphylococcus aureus and Pseudomonas aeruginosa strains. These coated antimicrobial cotton fabrics can be applied in different medical textiles. (C) 2018 Elsevier Ltd. All rights reserved.
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Calcium phosphate ceramics, owing to their resemblance to bone structure, are widely used for different biomedical applications. However, such a specific bone-structure pattern is making those materials susceptible to colonisation...
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Calcium phosphate ceramics, owing to their resemblance to bone structure, are widely used for different biomedical applications. However, such a specific bone-structure pattern is making those materials susceptible to colonisation by pathogenic bacteria. This work presents results of the study on physical characterisation and microbiological assessment of biocide properties of modified man-made fluor- and hydroxyapatites. The structures and physical properties were characterised by a diffuse reflectance spectra, FTIR, Raman spectroscopy, TEM and Zeta-potential analyses. The bactericidal properties were assessed with Staphylococcus aureus, the main pathogenic species responsible for implant-associated infections. It was found that manufactured materials had structures typical for the biological (bone) apatites. Doping with silver has not changed their morphology. Results from the assays have confirmed that built-in silver substantially increased their biocidal properties, thus Ag-doped fluorapatite is a promising new resistant biomaterial with great bactericidal effect that potentially could be applied in tissue engineering, or dentistry.
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Nanosilver is one of the first nanomaterials to be closely monitored by regulatory agencies worldwide motivating research to better understand the relationship between Ag characteristics and antibacterial activity. Nanosilver immo...
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Nanosilver is one of the first nanomaterials to be closely monitored by regulatory agencies worldwide motivating research to better understand the relationship between Ag characteristics and antibacterial activity. Nanosilver immobilized on nanostructured silica facilitates such investigations as the SiO2 support hinders the growth of nanosilver during its synthesis and, most importantly, its flocculation in bacterial suspensions. Here, such composite Ag/silica nanoparticles were made by flame spray pyrolysis of appropriate solutions of Ag-acetate or Ag-nitrate and hexamethyldisiloxane or tetraethylorthosilicate in ethanol, propanol, diethylene glucolmonobutyl ether, acetonitrile or ethylhexanoic acid. The effect of solution composition on nanosilver characteristics and antibacterial activity against the Gram negative Escherichia coli was investigated by monitoring their recombinantly synthesized green fluorescent protein. Suspensions with identical Ag mass concentration exhibited drastically different antibacterial activity pointing out that the nanosilver surface area concentration rather than its mass or molar or number concentration determine best its antibacterial activity. Nanosilver made from Ag-acetate showed a unimodal size distribution, while that made from inexpensive Ag-nitrate exhibited a bimodal one. Regardless of precursor composition or nanosilver size distribution, the antibacterial activity of nanosilver was correlated best with its surface area concentration in solution.
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In the past years, new environmentally-friendly photocatalysts have been reported, but the realization of efficient visible-light driven photocatalyst with highly active bactericidal and fungicidal activity is still challenging. T...
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In the past years, new environmentally-friendly photocatalysts have been reported, but the realization of efficient visible-light driven photocatalyst with highly active bactericidal and fungicidal activity is still challenging. This work is a joint experimental and theoretical study on the structural, electronic, and optical properties of Ag_2CrO_4:Zn~(2+) (ACOxZn, x = 1%, 2%, and 4%) solid solutions for photocatalytic, bactericidal, and fungicidal activity. For the first time, synthesis of these innovative and multifunctional materials were performed through the cation exchange of zinc and silver using a simple, fast, and cheap co-precipitation method. Powder X-ray diffraction measurements revealed the long range order of the materials. X-ray photoelectron spectroscopy provided information about the surface of the samples demonstrating that they were pure. The materials showed short-range order as verified by FT-Raman spectroscopy. Additionally, ultraviolet-visible diffuse reflectance spectra and photoluminescence spectroscopy were used to examine the electronic properties which corroborated with the increasing photocatalytic activity for the degradation of Rhodamine B and bactericidal activity against Staphylococcus aureus and Candida albicans. Field emission scanning electron microscopy images showed different types of particles with different facets and sizes. Theoretical results based on density functional theory calculations complement the experimental results to rationalize the effects of the incorporation of Zn cations in the ACO host lattice.
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Several bactericide inorganic materials have been used for the purification of water with varying success. The characterisation of the incorporation of Ag or Cu cations in montmorillonite (MMT) clay, to obtain a bactericide materi...
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Several bactericide inorganic materials have been used for the purification of water with varying success. The characterisation of the incorporation of Ag or Cu cations in montmorillonite (MMT) clay, to obtain a bactericide material against E. coli, indicated that both outer and interlayer surfaces act as adsorption sites of AgO and Ag_2O or CuO, respectively. The Ag-exchanged clays retain their bactericide ability even after being stirred in aqueous suspension, whereas samples with the highest concentration of Cu do not inhibit bacterial growth. Experiences from supernatants of Cu-exchanged clays indicated that bactericide capacity was present at high clay concentration.
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