Bioactive cationic polymer-based hydrogel with Engrailed-1 gene silencing and microenvironment modulation for enhanced scarless diabetic wound healing

Effective scarless healing of diabetic wounds remains challenging owing to dysregulated microenvironments, impaired vascularization and fibrous scar tissue formation. The activation of Engrailed-1 (EN1) gene in fibroblasts at the wound area plays a vital role in scar formation and knocking-down EN1 gene expression using siEN1 may inhibit scar formation. Herein, a bioactive cationic polymer-based pH/redox dual-responsive hydrogel (HPFS) loaded with siEN1 and deferoxamine mesylate (DFO) is designed to promote scarless diabetic wound healing by silencing EN1 gene and modulating microenvironment. HPFS had excellent self-healing behavior, tissue adhesive feature, rapid hemostasis ability, antioxidation and anti-inflammatory properties, which could scavenge reactive oxygen species (ROS) to alleviate oxidative stress and promote M2 macrophage polarization. HPFS enhanced cell proliferation, migration, and tube formation of endothelial cells, as well as upregulated gene expressions of vascular endothelial growth factor (VEGF), angiogenin (ANG), α-actin and collagen type III (Col III) with negligible cytotoxicity. Specially, HPFS could effectively deliver siEN1 for excellent EN1 gene silencing in fibroblasts. Importantly, HPFS accelerated scarless diabetic wound healing by anti-inflammatory, antioxidation, stimulating cell proliferation, angiogenesis, collagen deposition, granulation tissue formation, re-epithelialization and down-regulating the expression of EN1 gene in vivo. This work suggests that bioactive HPFS hydrogel can be used as a promising candidate for scarless wound healing.