Zinc Oxide Nanoparticles Dispersed in Ionic Liquids Show High Antimicrobial Efficacy to Skin-Specific Bacteria

Zinc oxide (ZnO) nanoparticles have been shown in the literature to have antibacterial properties and have been widely used in antibacterial formulations. However, one of the problems with ZnO nanoparticles is their tendency to aggregate, thereby causing damage to normal cells and lowering their antibacterial efficacy during application. In this work, we have attempted to avoid this by using a combination of ZnO nanoparticles and ionic liquids, a class of low melting salts containing organic cations and organic/inorganic anions that show antibacterial property as well, and tested the antibacterial activity of this dispersion. ZnO nanoparticles of 60 nm were dispersed in two different ionic liquids—choline acetate (IL1) and 1-butyl-3-methylimidazolium chloride (IL2)—to achieve high dispersibility, whereas ZnO dispersed in phosphate-buffered salinewas taken as a control. These dispersions were tested on four strains—Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, and Staphylococcus epidermidis....