IR820 Sensitized Ceria Nanozyme via PDA Bridging for Multifaceted Antibacterial Wound Healing Therapy

Abstract

Nanozymes with peroxidase (POD)-like activity hold significant potential for addressing antibiotic-resistant bacterial infections. However, their catalytic efficiency and therapeutic efficacy need further improvement to broaden their clinical applications. A key challenge is achieving efficient energy transfer from photosensitizing molecules to nanozymes, which is critical for enhancing catalytic performance. In this study, a universal strategy is developed to bridge nanozymes and photosensitizing molecules, designing photoactivated nanozymes called IR820/PDA@mCeO₂ (IR/P@Ce). By integrating IR820, a photosensitizer, with mesoporous ceria (mCeO₂), it facilitates efficient electron transfer through polydopamine (PDA) bridge molecules, resulting in enhanced POD-like catalytic performance and reactive oxygen species production. Additionally, PDA stabilized the nanozyme, improved photothermal therapy, and enhanced photodynamic therapy under near-infrared light exposure, further amplifying bacterial destruction. This multifunctional nanozyme demonstrated strong antibacterial efficacy against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Moreover, its synergistic approach not only facilitated bacterial eradication but also accelerated wound healing in vivo, making it a promising therapeutic alternative for managing bacterial infections and promoting tissue regeneration.