pH Switchable Nanozyme Platform for Healing Skin Tumor Wound Infected with Drug‐Resistant Bacteria

Abstract Nanozymes capable of generating reactive oxygen species have recently emerged as promising treatments for wounds infected with drug‐resistant bacteria, possessing a reduced possibility of inducing resistance. However, the therapeutic effect is limited by a shortage of endogenous oxy‐substrates and undesirable off‐target biotoxicity. Herein, a ferrocenyl coordination polymer (FeCP) nanozyme, featuring pH switchable peroxidase (POD)‐ and catalase (CAT)‐like activity is incorporated with indocyanine green (ICG) and calcium peroxide (CaO 2 ) to fabricate an H 2 O 2 /O 2 self‐supplying system (FeCP/ICG@CaO 2 ) for precise treatment of bacterial infections. At the wound site, CaO 2 reacts with water to generate H 2 O 2 and O 2 . Acting as a POD mimic under an acidic bacterial microenvironment, FeCP catalyzes H 2 O 2 into hydroxyl radicals to prevent infection. However, FeCP switches to CAT‐like activity in neutral tissue, decomposing H 2 O 2 into H 2 O and O 2 to prevent oxidative damage and facilitate wound healing. Additionally, FeCP/ICG@CaO 2 shows photothermal therapy capability, as ICG can emit heat under near‐infrared laser irradiation. This heat assists FeCP in fully exerting its enzyme‐like activity. Thus, this system achieves an antibacterial efficiency of 99.8% in vitro for drug‐resistant bacteria, and effectively overcomes the main limitations of nanozyme‐based treatment assays, resulting in satisfactory therapeutic effects in repairing normal and special skin tumor wounds infected with drug‐resistant bacteria.