Efficient organic nanoparticles for photothermal antibacterial activity and immune regulation to promote maxillofacial wound healing and scarless repair

Treating maxillofacial infections is hindered by severe inflammation and bacterial biofilms, which delay healing and often result in significant scarring. Photothermal therapy (PTT), which utilizes a photothermal agent (PTA) to generate localized heat, presents a promising approach that effectively eliminates pathogens while minimizing tissue damage, thereby enhancing treatment safety and efficacy. However, challenges such as low photothermal conversion efficiency and biocompatibility issues persist. In this study, we developed hemin chloride-modified organic small molecule-based nanoparticles (PTA@Hemin NPs). This material demonstrates exceptional photothermal effects with 81 % photothermal conversion efficiency and excellent biocompatibility. Under near-infrared (NIR) laser irradiation, the PTA@Hemin NPs generate strong photothermal effects, which synergize with the inherent antibacterial properties of hemin to significantly enhance the eradication of free bacteria and biofilms. Furthermore, PTA@Hemin NPs effectively scavenge reactive oxygen species (ROS) and alleviate inflammation by downregulating the expression of pro-inflammatory factors such as Cd86 and Il-1α, reducing M1 macrophage polarization. Both in vitro and in vivo experiments confirmed that PTA@Hemin NPs significantly enhance antibacterial and anti-inflammatory effects, while facilitating scarless healing of maxillofacial wounds in mice. These results highlight the potential of PTA@Hemin NPs as a highly effective strategy for treating bacterial infections, particularly those involving biofilms, in future clinical applications.