Multifunctional EGCG@ZIF‑8\nNanoplatform with\nPhotodynamic Therapy/Chemodynamic Therapy Antibacterial Properties\nPromotes Infected Wound Healing

Damaged skin is susceptible to invasion by harmful microorganisms,\nespecially <i>Staphylococcus aureus</i> and <i>Escherichia\ncoli</i>, which can delay healing. Epigallocatechin-3-gallate\n(EGCG) is a natural compound known for effectively promoting wound\nhealing and its potent anti-inflammatory effects. However, its application\nis limited due to its susceptibility to oxidation and isomerization,\nwhich alter its structure. The use of zeolitic imidazolate framework-8\n(ZIF-8) can effectively tackle these issues. This study introduces\nan oxygen (O<sub>2</sub>) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) self-supplying ZIF-8 nanoplatform designed to enhance the\nbioavailability of EGCG, combining photodynamic therapy (PDT) and\nchemodynamic therapy (CDT) to improve antibacterial properties and\nultimately accelerate wound healing. For this purpose, EGCG and indocyanine\ngreen (ICG), a photosensitizer, were successively integrated into\na ZIF-8, and coated with bovine serum albumin (BSA) to enhance biocompatibility.\nThe outer layer of this construct was further modified with manganese\ndioxide (MnO<sub>2</sub>) to promote CDT and calcium peroxide (CaO<sub>2</sub>) to supply H<sub>2</sub>O<sub>2</sub> and O<sub>2</sub>,\nresulting in the final nanoplatform EGCG-ICG@ZIF-8/BSA-MnO<sub>2</sub>/CaO<sub>2</sub> (EIZBMC). In <i>in vitro</i> experiments\nunder 808 nm laser, EIZBMC exhibited synergistic antibacterial effects\nthrough PDT and CDT. This combination effectively released reactive\noxygen species (ROS), which mediated oxidative stress to inhibit the\nbacteria. Subsequently, in a murine model of wound infection, EIZBMC\nnot only exerted antibacterial effects through PDT and CDT but also\nalleviated the inflammatory condition and promoted the regeneration\nof collagen fibers, which led to accelerated wound healing. Overall,\nthis research presents a promising approach to enhancing the therapeutic\nefficacy of EGCG by leveraging the synergistic antibacterial effects\nof PDT and CDT. This multifunctional nanoplatform maximizes EGCG’s\nanti-inflammatory properties, offering a potent solution for promoting\ninfected wound healing.