Oxygen vacancy mediated α-MoO3 bactericidal nanocatalyst in the dark: Surface structure dependent superoxide generation and antibacterial mechanisms

Understanding bacteria inactivation mechanisms of nanomaterials on the surface molecular level is of prime importance for the development of antibacterial materials and their application in restraining the transmission of pathogenic microorganisms. This study prepared an oxygen vacancy-mediated bactericidal nanocatalyst α-MoO3 which exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus in the dark. By manipulating the surface structure of α-MoO3, the facile tuning of superoxide radical (•O2-) generation can be achieved, which was confirmed by electron paramagnetic resonance. •O2- disrupted bacterial membrane through attacking lipopolysaccharide (LPS) and phosphatidylethanolamine (PE). Intracellular reactive oxygen species (ROS) experiments confirm that oxidative stress induced by •O2- also played a vital role in bacterial inactivation, which might account for DNA damage verified by comet assays. The α-MoO3 with rich oxygen vacancies also exhibited good antibacterial efficiency (＞99.00 %) toward airborne microbes under dark conditions, indicating its potential to impede the transmission of pathogenic microbes.