Light-Driven Double-Layer Polydopamine-Coated Flexible Metal–Organic Frameworks: Balancing Antibacterial and Regenerative Functions

Burns complicated by antibiotic-resistant bacterial infections present a formidable clinical challenge, characterized by key pathological processes, including pathogen colonization, chronic inflammatory responses, and excessive accumulation of reactive oxygen species (ROS). Photocatalytic metal-organic frameworks (MOFs) have emerged as a promising nonantibiotic strategy against antibiotic-resistant bacterial infections. However, the ROS generated by MOF-based photocatalysis is often insufficient for effective antibacterial activity, while excessive ROS may induce tissue injury. Therefore, the precise control of ROS levels to strike a balance between antibacterial efficacy and biosafety represents a crucial challenge in the realm of photocatalytic antibacterial strategies. In this study, we innovatively developed a flexible MOF nanomaterial coated with a dual-layer polydopamine (PDA) structure. The band gap of the material is reduced to 1.26 eV, thereby extending the photocatalytic response range into the near-infrared (NIR) region (808 nm) and significantly enhancing photocatalytic efficiency. Simultaneously, the material efficiently mitigates surplus ROS by leveraging the antioxidant attributes of PDA, thereby mitigating oxidative stress. Additionally, the coordinated and sustained release of zinc ions and metformin (Met) synergistically modulates the redox balance, mitigates inflammatory reactions, and fosters tissue regeneration. In an animal model of burn injuries afflicted with antibiotic-resistant bacterial infections, The composite exhibited outstanding biological properties, achieving 97.7% antibacterial inhibition and 98.4% wound recovery rate. Overall, this study has developed a multifunctional photocatalytic MOF-based material that integrates high antibacterial efficacy, anti-inflammatory properties, and tissue repair capabilities. This material offers a strategy for the treatment of infected wounds, showcasing considerable clinical relevance, particularly in combating antibiotic-resistant bacterial infections and facilitating chronic wound healing.