Photoactive cationic conjugated microporous polymers containing pyrimidine with an ‘adsorption-kill’ antibacterial strategy for infected wound healing

Pathogenic bacterial invasion leads to severe inflammation that hinders wound healing, and it has become a major medical threat worldwide. Photodynamic therapy (PDT) has emerged as a promising strategy for treating microbial infection; however, developing a dressing with PDT effect and excellent biological functions poses a formidable challenge. Herein, a novel cationic pyrimidine-modified conjugated microporous polymer, BPyMe-CMP, was rationally designed and synthesized via a Sonogashira-Hagiwara and SN2 substitution reaction. The BPyMe-CMP exhibited weak interfacial charge transfer resistance and demonstrated superior photoinducible carrier separation, thereby displaying an excellent photoelectric response. Consequently, the BPyMe-CMP could readily generate reactive oxygen species under visible light irradiation to kill bacteria. In addition to enhancing the photogenerated electron transfer process, BPyMe-CMP also provided abundant attraction sites for bacteria to reinforce the antibacterial ability. The deposition of BPyMe-CMP onto polyvinyl alcohol-modified silk fibroin (SF/PVA) film served as a wound dressing to promote healing. The in vitro and in vivo experiments revealed that the SF/PVA@BPyMe-CMP induced M2-type macrophage polarization, promoted L929 fibroblast migration, exhibited bactericidal activity, and induced angiogenesis, which synergistically accelerated the healing of methicillin-resistant Staphylococcus aureus-infected wounds. This study provides data support to advance the construction of a multi-functional wound dressing based on pyrimidination and cationization for the treatment and rapid healing of infected wounds.