Size-dependent inhibition of bacterial growth by chemically engineered spherical ZnO nanoparticles

Abstract

The antibacterial effect of ZnO nanoparticles is tested against Staphylococcus aureus, (a Grampositive pathogenic bacterium) from a particle-size, concentration, and surface-defects point of view. Activation of antibacterial activity was achieved by standard well diffusion agar and minimum inhibitory concentration procedures. Our results show that smaller-sized particles are more effective inhibitors of bacterial activity when used in a certain optimum concentration. To reveal the underlying mechanism of the observed size and concentration-dependent bacterial activity inhibition, we measured the concentrations of Zn 2+ ions released in each suspension by an inductive couple plasma optical emission spectrophotometer. Additionally, photoluminance spectra of our samples show significant surface defects (mainly oxygen vacancies) that generate reactive oxygen species. The underlying mechanism of the observed size-and concentration-dependent bacterial activity inhibition is attributed primarily to the release of Zn 2+ ions and generation of reactive oxygen species that interact and penetrate the cell membrane, causing lethal damage to the cell. Finally, the antibacterial effectiveness and maximum sensitivity of our nanoparticles is confirmed by optical density measurements. Keywords Zinc oxide. Reactive oxygen species ROS. Zn 2+ ion release. Antibacterial activity mechanism. Nanoparticles

Toxicity of Different Zinc Oxide Nanomaterials at 3 Trophic Levels: Implications for Development of Low-Toxicity Antifouling Agents

“…Out of these factors, concentration and availability of free Zn 2+ ions correlate best with the toxic potential of the nanostructure (Brunner et al 2006). Similar results were observed in a recent study of Naqvi et al (2019). Free Zn 2+ ions have the highest bioavailability, whereas ZnO supported on structures has the lowest bioavailability (Lanone et al 2009).…”

Callus mediated biosynthesis and antibacterial activities of zinc oxide nanoparticles from Viola canescens: an important Himalayan medicinal herb

“…8). Statistical analysis for the amount of nanoparticles dependent bactericidal activity showed significant variation by DMRT at 0.5% and maximum zone of inhibition attributed to high concentration of nanoparticles, and among different bacteria maximum zone of inhibition [17,24,36,46,76,79], the present finding confirm the same because leaf (26 nm) and root (11 nm) based nanoparticle proved inferior in comparison to callus based nanoparticles [31,33] (Fig. 9).…”

Antibacterial action and target mechanisms of zinc oxide nanoparticles against bacterial pathogens

“…The teichoic acid in the peptidoglycan layer and the lipoteichoic acid in the membrane are the source of negative charges in the cell surface. Positive charges from ZnO NPs are attracted to the cell surface by electrostatic interactions, and the difference in electrostatic gradient leads to damage in the cell surface 37 , 38 . Teicoic and lipoteichoic acids act as a chelating agent on Zn 2+ ions, which are then carried by passive diffusion across membrane proteins (Fig.…”