Antibacterial Action and Physicochemical Properties of Stabilized Silver and Gold Nanostructures on the Surface of Disperse Silica

Abstract

This work is devoted to the synthesis and stabilization of nanosized Ag/SiO 2 and Au/SiO 2 disperse materials and investigation their morphology, optical and antimicrobial properties. First, Ag and Au nanoparticles (NPs) were produced in colloids via chemical (Ag) or photochemical (Au) reduction of appropriate ions. To prevent the oxidation of Ag NPs in colloid solution, external binary stabilizing agents PVP and SDS were used. Then, Ag and Au NPs (0.01-0.05% wt) were adsorbed from their colloid solutions on high disperse silica surface (S sp =260m 2 /g) and samples prepared were dried. Materials obtained were studied by UV-vis, XRD, and TEM methods. Ag and Au NPs adsorbed on silica demonstrated a fair crystallinity in XRD. The surface plasmon resonance (SPR) band positions inherent to Ag and Au NPs on silica surface as well as the intensities of optical spectra were stable during 7 month and more. Obtained Ag NPs in colloids and Ag/SiO 2 composites demonstrated excellent antimicrobial activity against a series of the microorganisms (Escherichia coli, Staphylococcus aurous, and Candida albicans). Au/SiO 2 samples did not reveal any bactericide properties relative to the test microorganisms grown. The mechanisms of Ag(Au) NPs interaction with silica surface were analyzed.

Silver and gold nanoparticles in silica matrices: synthesis, properties, and application

“…We showed that the biocidal characteristics of gold nanoparticles show up well when they are used at the growth stage of E. coli, while silver nanoparticles are effective during the elimination of already grown colonies [123][124][125]. The effectiveness of the nanoparticles can be intensified by depositing them on a support with a highly developed surface.…”

“…The Ag nanoparticles obtained during the high-temperature solvolysis of an ethanol solution of AgNO 3 in the presence of dodecanethiol also remain stable after drying [25]. The principle of the stabilization of Ag nanoparticles with polymers or surfactants was applied successfully to the synthesis of composite systems based on highly dispersed silica (HDS) containing stable nanoparticles of silver with PVP and/or SDS as stabilizers [124,125].…”

“…The shell of stabilizer around the Ag nanoparticles on the surface of the SiO 2 is stable up to temperatures of 85-90°C [124,125].…”

Treating Polymicrobial Infections in Chronic Diabetic Wounds

“…The antibacterial properties of gold NPs (Au-NPs) have also been evaluated. In one study, Au-NPs with a size of 20 to 30 nm showed no antibacterial effect on S. aureus ATCC 6538 and E. coli K-12 NCTC 10538 (64). The MIC of Au-NPs against S. aureus was also shown to be significantly higher than that of Ag-NPs (65).…”

Environmentally sustainable route to SiO2@Au–Ag nanocomposites for biomedical and catalytic applications

“…Although the exact mechanism of antibacterial effect of gold nanoparticles is not fully understood but it is assumed that Au NPs binds to the cell wall of the bacterium and suppressed bacterial growth at the rst stage of their reproduction. 64 Due to their well-developed surface chemistry and the smaller size, gold nanoparticles can interact with the microorganisms with ease and cause destructive effects on them. 65 SiO 2 @Ag nanoparticles showed better antibacterial effects than the SiO 2 @Au nanoparticles and were able to hinder the growth of both bacterial species.…”