A tactfully designed photothermal agent collaborating with ascorbic acid for boosting maxillofacial wound healing

ABSTRACT Maxillofacial injuries that may cause severe functional and aesthetic damage require effective and immediate management due to continuous exposure to diverse microbial populations. Moreover, drug resistance, biofilm formation, and oxidative stress significantly impede timely bacterial removal and immune function, making the exploration of advanced materials for maxillofacial wound healing an appealing yet highly challenging task. Herein, a near-infrared photothermal sterilization agent was designed, encapsulated with liposomes and coated with ascorbic acid known for its antioxidant and immune-regulatory functions. The resulting nanoparticles, 4TPE-C6T-TD@AA, effectively neutralize reactive oxygen species generated by lipopolysaccharides, facilitate the conversion of pro-inflammatory M1 macrophages to anti-inflammatory M2 macrophages, and eliminate >90% of Staphylococcus aureus and Escherichia coli by disrupting bacterial physiological functions upon exposure to 808 nm laser irradiation. In vivo experiments demonstrate that 4TPE-C6T-TD@AA rapidly eliminates bacteria from infected wounds in the maxillofacial region of rats, and significantly promotes healing in S. aureus-infected wounds by enhancing collagen formation and modulating the inflammatory microenvironment. In conclusion, this study presents a promising therapeutic strategy for effectively combating bacterial infections and excessive inflammation in treating maxillofacial injuries.