Bio-heterojunction-engineered recombinant collagen hydrogel orchestrates multimodal sterilization and immunomodulation for MRSA-infected wound healing

Multidrug-resistant (MDR) bacterial infections, notably methicillin-resistant <i>Staphylococcus aureus</i> (MRSA), necessitate innovative antibiotic-free wound therapies. Here, a bio-heterojunction-integrated recombinant collagen hydrogel (CAP@MXene/CuTCPP) is designed that synergistically combines photothermal therapy (PTT), photodynamic therapy (PDT), and peroxidase-like (POD-like) activity for multimodal antibacterial action. The borate-bonded dynamically crosslinked hydrogel is composed of polyvinyl alcohol (PVA), 3-aminophenylboronic acid (APBA)-modified recombinant collagen (CF-1552), and MXene/CuTCPP bio-heterojunctions (bio-HJs). Under 808 nm near-infrared (NIR) irradiation, the MXene/CuTCPP bio-HJs exhibit a high photothermal conversion efficiency (44.51%), inducing localized hyperthermia to disrupt bacterial membranes. Importantly, the construction of a Schottky junction at the MXene/CuTCPP interface significantly accelerates photo-excited electron transfer, thereby catalytically amplifying the production of additional ROS (¹O₂, ·O₂ ^-, ·OH) for synergistic bacterial eradication. This triple antibacterial mechanism ensures a 99.95% MRSA eradication rate without inducing drug resistance, while effectively removing the biofilm. In vivo, the hydrogel accelerates wound closure (98% by day 11) not only by providing a biomimetic scaffold but also by regulating the polarization of macrophages from M1 to M2, and significantly promoting angiogenesis. This work presents a biocompatible and self-adaptable platform that overcomes the killing-healing trade-off through synergistic energy/charge transfer integration, offering insights for advanced immunomodulatory wound management.