Construction of Ag-decorated ZnO with oxygen vacancies for enhanced antibacterial activity via increased H2O2 production

Ag-decorated ZnO nanorods with different Ag contents were prepared by deposition-precipitation method, which demonstrated enhanced inhibition ability for the common pathogen, especially exhibited excellent antibacterial effects on clinical drug resistant bacteria. Moreover, Ag-decorated ZnO nanorods presented much lower cytotoxicity to HEK293 cell than that of silver nanoparticles (AgNPs). The electron spin resonance (ESR) spectra revealed that oxygen vacancies (VO) were formed in ZnO after the decoration of AgNPs. To understand the improved antibacterial activity of Ag-decorated ZnO nanorods, reactive oxygen species (ROS) were determined. It was found that more H2O2 were generated over Ag-decorated ZnO compared to pure ZnO, which was closely related to the oxygen vacancy (VO) concentration. The production of large amount of H2O2 resulted in more serious membrane leakage of cytosol and dehydrogenation inactivation of respiratory chain for bacterial, thus leading to the enhanced antibacterial activities of Ag-decorated ZnO nanorods.