Hypoxia-Activated\nBiodegradable Porphyrin-Based Covalent\nOrganic Frameworks for Photodynamic and Photothermal Therapy of Wound\nInfection

Wound infections have gradually become a major threat\nto human\nhealth. Recently, covalent organic frameworks (COFs) have shown great\npotential in antibacterial and wound healing; however, difficult biodegradability\nand long-time <i>in vivo</i> retention limit their further\napplication. Herein, biodegradable COFs containing porphyrin backbones\nand hypoxia-sensitive azobenzene group, namely, HRCOFs, are fabricated\nfor photodynamic therapy (PDT) and photothermal therapy (PTT) of wound\ninfection. Due to the introduction of a porphyrin molecule, HRCOFs\ncan produce singlet oxygen (<sup>1</sup>O<sub>2</sub>) under 660 nm\nlaser irradiation. The prepared HRCOFs can also generate thermal energy\nunder 808 nm NIR laser irradiation. HRCOFs show excellent synergetic\nantibacterial ability against Staphylococcus aureus (S. aureus) and Escherichia\ncoli (E. coli<i>) in vitro</i>. The <i>in vivo</i> experiments also\ndemonstrate synergistic PDT and PTT effects of HRCOFs against wound\ninfection. Importantly, HRCOFs are response to wound microenvironment,\ncan be degraded for clearance, and avoid some adverse effects caused\nby long-time retention <i>in vivo</i>, exhibiting good biocompatibility.\nIn general, the obtained biodegradable HRCOFs with both photodynamic\nand photothermal effects can be used for antibacterial infections\nand provide great value for promoting wound healing.