Abstract
Immunoregulation is an emerging treatment strategy to promote wound healing by modulating the local immune system at the wound site. In this study, an extracellular matrix biomimetic and polysaccharide-based hydrogel was engineered to regulate the wound immune environment through Michael-type addition between maleimidyl pullulan and chitosan modified with hydroxyproline. The proposed hydrogel exhibited favorable injectable and self-healing properties, which facilitated the full coverage of irregularly shaped wounds. A natural polyphenol, epigallocatechin-3-gallate (EGCG), was incorporated into hydrogels, which thereby exhibited excellent biocompatibility, good reactive oxygen species (ROS) scavenging ability, anti-inflammatory activity, and antibacterial properties against S. aureus and E. coli. Furthermore, evaluations of a full-thickness skin defect mice model showed that the hydrogel with EGCG effectively alleviated the inflammatory response by reducing pro-inflammatory cellular infiltration and down-regulating the inflammatory cytokine TNF-α, while up-regulating anti-inflammatory cytokine IL-10. Notably, a faster wound healing rate was also achieved by the better promotion effect of the hydrogel on increasing the formation of re-epithelialization, granulation tissue generation, collagen deposition, and angiogenesis. Therefore, our immunoregulatory strategy showed great potential in the design of biomaterials for wound management.