Enhanced bioactivity of ZnO nanoparticles—an antimicrobial study

TLDR

The study investigates the antibacterial activity of ZnO nanoparticles across different particle sizes. ZnO nanoparticles were synthesized via base hydrolysis of zinc acetate in 2‑propanol and via precipitation with Zn(NO₃)₂/NaOH, characterized by XRD, TEM, and PL, and tested for antibacterial activity using MIC and disk diffusion in agar and broth media. ZnO nanoparticles exhibit stronger biocidal activity than bulk ZnO, with efficacy increasing as particle size decreases, likely due to abrasiveness and surface oxygen species.

Abstract

In this study, we investigate the antibacterial activity of ZnO nanoparticles with various particle sizes. ZnO was prepared by the base hydrolysis of zinc acetate in a 2-propanol medium and also by a precipitation method using Zn(NO3)2 and NaOH. The products were characterized by x-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Bacteriological tests such as minimum inhibitory concentration (MIC) and disk diffusion were performed in Luria-Bertani and nutrient agar media on solid agar plates and in liquid broth systems using different concentrations of ZnO by a standard microbial method for the first time. Our bacteriological study showed the enhanced biocidal activity of ZnO nanoparticles compared with bulk ZnO in repeated experiments. This demonstrated that the bactericidal efficacy of ZnO nanoparticles increases with decreasing particle size. It is proposed that both the abrasiveness and the surface oxygen species of ZnO nanoparticles promote the biocidal properties of ZnO nanoparticles.