A pH-responsive copper selenide nanozyme modulates multiple enzyme activities for improved healing of infected wounds

Bacterial infections can slow down wound healing and pose a threat to human health, which remains a challenging issue in clinical practice. The rise of nanozymes has provided new therapeutic approaches for antimicrobial treatment. Here, we report pH-responsive copper selenide nanoparticles (Cu1.79Se, hereafter referred to as CuSe), which exhibits peroxidase (POD)-like activity under weakly acid bacterial infection conditions, generating highly reactive hydroxyl radicals (center dot OH) that kill bacteria and alleviate wound infections. In the later stages of wound healing, it is neutral or weakly alkaline, the CuSe nanoparticles shows catalase (CAT) and superoxide dismutase (SOD)-like activities, clearing excessive reactive oxygen species (ROS) and producing O2, thus protecting normal tissues from damage caused by both external and endogenous ROS. The above feature helps damaged tissue cells regain their ability to proliferate and migrate, also promotes angiogenesis, achieving a "two birds with one stone" effect. It is expected that the CuSe nanoparticles could be a promising antimicrobial agent for wound healing.