Porphyrin‑manganese trioxide-doped chitosan hydrogel with self‑oxygen supply enhancing photodynamic therapy effect for antibacterial and anti-inflammatory of infected wounds.

To combat microbial infection and persistent inflammation of wounds, the increasing type and dosage of antibiotics in wound dressing results in the formation of drug-resistant bacteria, which seriously delays the healing of infected wounds. Thus, to develop alternative antibacterial wound dressings independent of antibiotics is imperative. In this work, we established a novel degradable hybrid nanohydrogel material (TAPP/Mn3O4@CS-GA) with antibacterial and anti-inflammation effects by loading 5,10,15,20-tetrakis (4-aminophenyl)-21H,23H-porphine (TAPP) with PDT function and Mn3O4 with SOD and CAT-like activities in chitosan hydrogel (CS-GA). The nanosystem can produce abundant ROS under laser irradiation, SOD and CAT-like activities of Mn3O4 generate enough O2 to provide substrate for PDT mediated by TAPP, increasing the concentration of singlet oxygen (1O2) and enhancing the PDT effect. After laser irradiation, SOD and CAT-like activities continue transfer superoxide anion free radical (O₂-·) and hydrogen peroxide (H2O2) to O2 to reduce inflammation caused by oxidative stress, relieve hypoxia and promote angiogenesis. The antibacterial experiments results show that the combination of antibacterial and anti-inflammation mediated by TAPP/Mn3O4@CS-GA hydrogel can accelerate infected wound healing.