Microenvironment-responsive release of Mg2+ from tannic acid decorated and multilevel crosslinked hydrogel accelerates infected wound healing

The management of chronic infected wounds poses significant challenges due to frequent bacterial infections, high concentrations of reactive oxygen species, abnormal immune regulation, and impaired angiogenesis. This study introduces a novel, microenvironment-responsive, dual dynamic, and covalently bonded hydrogel, termed OHA-P-TA/G/Mg2+. It is derived from the reaction of Tannic acid (TA) with Phenylboronic acids (PBA), which are grafted onto oxidized hyaluronic acid (OHA-P-TA), combined with GelMA (G) via Schiff base and chemical bonds, and incorporates Mg2+. This hydrogel exhibits pH and ROS dual-responsiveness, demonstrating effective antibacterial capacity, antioxidant ability, and the initiation of inflammation under distinct acidic and oxidative microenvironments. Furthermore, the release of Mg2+ from the TA-Mg2+ network (TA@Mg2+) promotes the transformation of pro-inflammatory M1 phenotype macrophages to anti-inflammatory M2 phenotype, showing a microenvironment-responsive response. Finally, in vivo results indicate that the OHA-P-TA/G/Mg2+ hydrogel enhances epithelial regeneration, collagen deposition, and neovascularization, showing great potential as an effective dressing for infected wound repair.