Oxygen‐Vacancy‐Mediated ROS Generation Mechanism of MgO Nanoparticles against Escherichia coli

Abstract The antibacterial property of MgO nanomaterials was strongly dependent on the surface defect‐mediated reactive oxygen species (ROS, such as . O 2 − , . OH and H 2 O 2 ) generation, which makes the construction of surface defects become very significant. This work demonstrated that the anti‐ Escherichia coli (E. coli) activity of MgO nanoparticles was obviously enhanced via N 2 calcination processes, with the antibacterial ratio of 95.7 % for MgO nanoparticles calcined in N 2 at 650 °C. The electron spin resonance (ESR) and X‐ray photoelectron spectroscopy (XPS) results indicated that rich oxygen vacancies on the surface of designed MgO nanoparticles could increase adsorbed oxygen content and further promote the activation of O 2 and generation of ROS. The fluorescence probe results also verified that high‐level ROS could accumulate in E. coli exposed to MgO nanomaterials. Besides, . O 2 − played a dominant role in the antibacterial property of MgO nanoparticles compared with . OH and H 2 O 2 . The above findings illustrated the correlation between oxygen vacancy‐mediated ROS generation and enhanced antibacterial activity in MgO nanoparticles calcined under N 2 atmosphere.