Antibacterial effect of silver nanorings

Abstract

Background: The emergence and expansion of antibiotic resistance makes it necessary to have alternative antiinfective agents, among which silver nanoparticles (AgNPs) display especially interesting properties. AgNPs carry out their antibacterial action through various molecular mechanisms, and the magnitude of the observed effect is dependent on multiple, not fully understood, aspects, particle shape being one of the most important. In this article, we conduct a study of the antibacterial effect of a recently described type of AgNP: silver nanorings (AgNRs), making comparisons with other alternative types of AgNP synthesized in parallel using the same methodology. Results: When they act on planktonic forms, AgNRs produce a smaller effect on the viability of different bacteria than nanoparticles with other structures although their effect on growth is more intense over a longer period. When their action on biofilms is analyzed, AgNRs show a greater concentration-dependent effect. In both cases it was observed that the effect on inhibition depends on the microbial species, but not its Gram positive or negative nature. Growth patterns in silver-resistant Salmonella strains suggest that AgNRs work through different mechanisms to other AgNPs. The antibacterial effect is also produced to some extent by the conditioning of culture media or water by contact with AgNPs but, at least over short periods of time, this is not due to the release of Ag ions. Conclusions: AgNRs constitute a new type of AgNP, whose antibacterial properties depend on their shape, and is capable of acting efficiently on both planktonic bacteria and biofilms.

Fighting Antibiotic Resistance in Hospital-Acquired Infections: Current State and Emerging Technologies in Disease Prevention, Diagnostics and Therapy

“…These materials include nanocone surfaces, nanowires, nanograss, nanospikes, nanopillars, and nanorings, etc. (Hazell et al, 2018;Gonzalez-Fernandez et al, 2020;Gudz et al, 2020;Jenkins et al, 2020). For example, black silicon (nanograss) was created by mimicking cicada wings nanoneedles, which are lethal not only to gram-negative P. aeruginosa, but also to gram-positive S. aureus and B. subtilis (Ivanova et al, 2013).…”

“…However, changing the structure may help overcome this resistance. For example, silver-resistant Salmonella strains exhibited susceptibility to silver nanoring structured NPs ( Gonzalez-Fernandez et al, 2020 ).…”

Green Synthesis of Silver Nanoparticles Using Nasturtium officinale L. Extract And Analysis of Their Antibacterial Activity Against Nosocomial Pathogens

“…The disk diffusion test and MIC / MBC assays were performed against both Gram-positive and Gram-negative bacteria to assess the potential of green nanosilver bactericidal effects. It should be attended that the antibacterial properties of AgNPs depend on their structure including the size, shape, colloidal state, preparation method, and the bacteria with which they interact (37,38,41). The exact mechanisms by which nanosilver performs antibacterial efficacy are still under verification.…”

A Promising Antifungal and Antiamoebic Effect of Silver Nanorings, a Novel Type of AgNP

“…In addition, the effect of AgNRs was compared against two other types of AgNPs, namely AgNSs and AgNWs. The biocidal effects of AgNSs and AgNWs were described previously in various studies, unlike those of AgNRs, whose activity has only been described in a single study against a broad spectrum of bacteria such as S. aureus , S. epidermidis , Streptococcus pyogenes , Streptococcus pneumoniae , E. faecalis , B. globisporus , E. coli , Serratia marcescens , Haemophilus influenzae , Klebsiella pneumoniae , Neisseria gonorrhoeae and Pseudomonas aeruginosa [ 20 ]. Due to the fact that the synthesis of these particles can be carried out by a variety of physical and chemical processes, and that their properties may vary, the comparison of these three morphologies was carried out after obtaining them in parallel using the same methodology.…”

“…A similar effect was observed in Escherichia coli , where triangular nanoparticles were found to be qualitatively more effective than those that were rod-like or spherical in shape [ 14 ]. A new ring-shaped AgNP morphology was recently described, and these NPs demonstrated greater effectiveness against a broad spectrum of bacteria such as Enterococcus faecalis , Streptococcus pneumoniae , E. coli and Neisseria gonhorreae in terms of biocidal activity when compared with spherical and wire-shaped NPs [ 20 ]. Since the 3 morphologies were obtained by the same procedure, the observed effect highlighted the influence of the shape on the antibacterial activity of AgNPs [ 20 ].…”