Insulin/PHMB-grafted sodium alginate hydrogels improve infected wound healing by antibacterial-prompted macrophage inflammatory regulation

Background Non-healing chronic wounds with high susceptibility to infection represent a critical challenge in modern healthcare. While growth factors play a pivotal role in regulating chronic wound repair, their therapeutic efficacy is compromised in infected microenvironments. Current wound dressings inadequately address the dual demands of sustained bioactive molecule delivery and robust antimicrobial activity. Results In this study, we developed a sodium alginate hydrogel (termed P-SA/Ins), which incorporated polyhexamethylene biguanide (PHMB) grafting and long-acting glargine insulin loading. P-SA/Ins exhibited the favorable physicochemical performance, biocompatibility and antibacterial efficacy against both Gram-negative and Gram-positive pathogens through inhibition of bacterial proliferation and biofilm formation. Glargine insulin was applied to prolonged insulin delivery. P-SA/Ins treatment attenuated S. aureus induced pro-inflammatory cytokine cascades in macrophages. The evaluation in vivo using a rat model with S. aureus infected wound demonstrated that P-SA/Ins significantly enhanced wound healing and optimized skin barrier through antimicrobial-mediated modulation of macrophage polarization and subsequent inflammatory cytokine profiling. Conclusions Our findings demonstrate that P-SA/Ins promotes wound healing and restores epidermal barrier integrity, indicating its potential as a therapeutic dressing for chronic wound healing, particularly in cases with infection risk. Graphical abstract