Monometallic ‘zinc oxide and copper oxide’ nanoparticles by ecofriendly synthesis for suppression of mastitis-causing bacteria via ξ potential

Abstract

Background Metallic nanoparticles (MNPs) are extensively employed in biology and medicine because they may freely pass through organisms’ barriers. Monometallic zinc oxide (MM ZnO) and copper oxide nanoparticles (CuO NPs) by ecofriendly synthesis are safe, economical, and promising future alternatives as antimicrobial agents. Objective This study focused on the functioning zeta (ξ) potential (ZP) of (MM ZnO) and (CuO NPs) for suppression of mastitis-causing bacteria. Materials and methods Monometallic nanoparticles (MMNPs) were biosynthesized by Bacillus megaterium and characterized by UV-Vis spectra, SEM-EDS, TEM, particle size distribution, ZP, and particle concentrations calculated by ICP-AES. Then, the biocidal activity of MM ZnO and CuO NPs against some mastitis causing bacteria isolates was studied. Results and conclusion The obtained data reveal that the resulting cationic ZnO and anionic CuO are zero-dimensional (0-D) oval and spherical NPs with 5–17 and 10–34 nm in size, respectively. The IC50 of the biosynthesized ZnO and CuO NPs was 1717±33.7 μg/ml and 1493±42.52 μg/ml, respectively. The obtained results showed no cytotoxic effect of the MMNPs on somatic cells. Data suggested that a high dose of 100 μg/ml of cationic ZnO represents a highly significant effect (P<0.05) over anionic CuO for suppressing mastitis bacteria. The terminus point was in evaluating the toxicity of MMNPs by comet assay; the effects of the variation were based on the ZP and interactivity of layers carrying opposite charges. These findings elucidate that cationic ZnO NPs have advantages in targeting pathogenic bacteria because of enhanced delivery to the cells, which causes water dehydration and decreases the moisture required for bacterial viability and plasmolysis via ionic interactions.