A Recyclable Coconut-Shell-Carbon-Based Photocatalyst for Robust Antimicrobial Activity and Enhanced Wound Repair

Acinetobacter baumannii (A. baumannii) is a notorious nosocomial pathogen for its extensive drug resistance and adaptability. This study developed a novel heterojunction photocatalyst (PC), PTQ10-SY1, supported on coconut shell charcoal (CSC), a carbon material derived from natural biomass. The CSC matrix ensures efficient dispersion of PTQ10-SY1 and enhances its recoverability, thereby synthesizing the reusable, environmentally friendly, white light-responsive material CSC@PTQ10-SY1. Under 13.2 mW/cm² of light excitation, the material efficiently generates reactive oxygen species (ROS), which disrupt the cell wall and membrane integrity of A. baumannii, inhibit ATP synthesis, and leading to bacterial death. It achieves significant elimination of A. baumannii within 30 min and also demonstrates effective activity against Methicillin-resistance Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa). In mammalian safety assessments, CSC@PTQ10-SY1 shows minimal adverse effects under the tested conditions. In a wound-associated infection model, topical application of CSC@PTQ10-SY1 significantly reduces bacterial burden and inflammation, resulting in improved wound healing outcomes compared to the control group. Furthermore, the material retains its composition and shows no evidence of tolerance to photodynamic therapy (PDT) after 10 cycles. This work highlights an innovative strategy for designing antimicrobial PC materials and promotes the application of antimicrobial PDT for the A. baumannii.