pH-responsive injectable hydrogel dressing integrating antibacteria, antioxidation, anti-inflammation, and angiogenesis for infected wound healing.

Infected wounds have presented a significant clinical challenge due to persistent inflammatory responses, elevated oxidative stress, and damaged blood vessels, which markedly impede the healing process. Here, we develop a multifunctional hydrogel dressing (named SMCC) based on sodium alginate, co-loaded with minocycline and curcumin, which exhibits pH-responsive characteristics. This hydrogel exhibits excellent injectability and adaptability, enabling it to conform to irregular wound surfaces and facilitate accelerated drug release in acid microenvironments, thereby synergistically exerting antibacterial, anti-inflammatory, and antioxidant effects. In vitro experiments demonstrate that SMCC hydrogel exhibits outstanding biocompatibility, effectively promotes cell migration, and enhances angiogenesis by upregulating VEGF and CD31 expression. Furthermore, the hydrogel significantly mitigates H2O2-induced oxidative stress by scavenging excess ROS. Importantly, SMCC hydrogel downregulates pro-inflammatory factors while upregulating anti-inflammatory markers, thereby inhibiting M1 polarization and promoting M2 polarization of macrophages. In rat models of full-thickness infected skin defect, SMCC hydrogel effectively remodels the inflammatory microenvironment, enhances vascularization and collagen deposition, and consequently accelerates wound healing and tissue regeneration. This study provides a promising functionalized hydrogel-based strategy for the comprehensive management of infected wounds.