POD Nanozyme optimized by charge separation engineering for light/pH activated bacteria catalytic/photodynamic therapy

The current feasibility of nanocatalysts in clinical anti-infection therapy,especially for drug-resistant bacteria infection is extremely restrained because of the insufficient reactive oxygen generation.Herein,a novel Ag/Bi2MoO6(Ag/BMO)nanozyme optimized by charge separation engineering with photoactivated sustainable peroxidase-mimicking activities and NIR-II photodynamic performance was synthesized by solvothermal reaction and photoreduction.The Ag/BMO nanozyme held satisfactory bactericidal performance against methicillin-resistant Staphylococcus aureus(MRSA)(~99.9%).The excellent antibacterial performance of Ag/BMO NPs was ascribed to the corporation of peroxidase-like activity,NIR-II photodynamic behavior,and acidity-enhanced release of Ag^(+).As revealed by theoretical calculations,the introduction of Ag to BMO made it easier to separate photo-triggered electronhole pairs for ROS production.And the conduction and valence band potentials of Ag/BMO NPs were favorable for the reduction of O_(2) to·O_(2)^(−).Under 1064 nm laser irradiation,the electron transfer to BMO was beneficial to the reversible change of Mo^(5+)/Mo^(6+),further improving the peroxidase-like catalytic activity and NIR-II photodynamic performance based on the Russell mechanism.In vivo,the Ag/BMO NPs exhibited promising therapeutic effects towards MRSA-infected wounds.This study enriches the nanozyme research and proves that nanozymes can be rationally optimized by charge separation engineering strategy.