Mechanistic investigation into antibacterial behaviour of suspensions of ZnO nanoparticles against E. coli

Aqueous suspensions containing 4.45 × 10−5 − 1.25 × 10−3 M ZnO particles exhibit a strong antibacterial activity against E. coli under the dark conditions. The dominant mechanisms of such antibacterial behaviour are found to be either or both of chemical interactions between hydrogen peroxide and membrane proteins, and chemical interactions between other unknown chemical species generated due to the presence of ZnO particles with the lipid bilayer. The effect of direct physical interactions between nanoparticles and biological cells are found to play a relatively small role under the conditions of this study.