Smart Hydrogel-Based DVDMS/bFGF Nanohybrids for Antibacterial Phototherapy with Multiple Damaging Sites and Accelerated Wound Healing

Burn infection is one of the commonest causes of death in severely burned patients. Developing multifunctional biological nanomaterials has a great significance for the comprehensive treatment of burn infection. In this paper, we developed a hydrogel-based nanodelivery system with antibacterial activity and skin regeneration function, which was used for photodynamic antimicrobial chemotherapy (PACT) in the treatment of burns. The treatment system is mainly composed of porphyrin photosensitizer sinoporphyrin sodium (DVDMS) and poly­(lactic-co-glycolic acid) (PLGA)-encapsulated basic fibroblast growth factor (bFGF) nanospheres that are embedded in carboxymethyl chitosan (CMCS)–sodium alginate to form CSDP hybrid hydrogel. We systematically evaluated the inherent antibacterial performance, rheological properties, fluorescence imaging, and biocompatibility of the CSDP nanosystem. Under mild photoirradiation (30 J/cm², 5 min), 10 μg/mL CSDP showed excellent antibacterial and anti-biofilm activities, which eradicated almost 99.99% of Staphylococcus aureus and multidrug-resistant (MDR) S. aureus in vitro. KEGG analysis identified that multiple signaling pathways were changed in MDR S. aureus after PACT. In the burn-infection model, CSDP-PACT successfully inhibited bacteria growth and concurrently promoted wound healing. Moreover, several regenerative factors were increased and some proinflammatory factors were reduced in the burn wounds of CSDP hydrogel treatment. These results suggest that the multifunctional CSDP hydrogel is a portable, light-triggered, antibacterial theranostic-platform and CSDP-PACT provides a promising strategy or the mechanically based synergistic treatment of burn infections.