Norepinephrine-induced hydrophilic Pd aerogels with photothermal-boosted multienzyme-like activity for chemodynamic therapy of MRSA infections

Nanozymes have become promising alternatives to antibiotics for fighting bacteria owing to their broad-spectrum antibacterial activity, robust stability, and multifunctionality. However, the deficient activity of nanozymes and the overexpressed glutathione in the infectious microenvironments extensively hamper their antibacterial efficiency. Herein, we present a norepinephrine (NE) induced Pd metallic aerogel as a highly efficient hydrophilic nanozyme for photothermal-enhanced chemodynamic therapy for bacterial infections and wound healing. The prepared NE-Pd aerogels exhibit satisfactory peroxidase-like and oxidase-like activity, which could generate an amount of hydroxyl radical and superoxide anion radical to cause irreversible damage to bacteria and decompose biofilm components with no bacteria resistance. In addition, the glutathione peroxidase-like activity of NE-Pd aerogels could deplete glutathione to adjust the infectious microenvironments for intensifying the generation of ROS, thus boosting the chemodynamic therapeutic efficacy. Furthermore, the intrinsic photothermal effect of NE-Pd aerogels generates hyperthermia to impair bacteria and further substantially promotes the multienzyme-like activity to damage bacteria and their biofilms. Consequently, the animal skin-wound model results further denoted that NE-Pd aerogels could effectively cure methicillin-resistant Staphylococcus aureus (MRSA) infected wounds with excellent in vivo biocompatibility in either wound tissue or living organisms. This work demonstrates that NE-Pd aerogel nanozymes have tremendous potential as a synergistically photothermal-catalytic antibacterial agent for treating bacterial infection and accelerating wound healing.