Fig. 6

Schematic illustration of the antimicrobial mechanism of ZnO NPs against bacterial cells. ZnO NPs act as an antimicrobial agent through the following mechanisms: (1) the formation of reactive oxygen species (ROS), which induces oxidative stress and membrane and DNA damage, resulting in bacterial death; (2) dissolution of ZnO NPs into Zn²⁺, which interferes with enzyme, amino acid, and protein metabolisms in bacterial cells; and (3) direct interaction between ZnO NPs and cell membrane through electrostatic forces that damages the membrane plasma and causes intracellular content leaks