New BMSC-Laden Gelatin Hydrogel Formed in Situ by Dual-Enzymatic Cross-Linking Accelerates Dermal Wound Healing

In situ forming hydrogel shows enormous potential as a therapeutic implant or carrier in tissue repair and regeneration. It can perfectly seal or fill the defective tissue, consequently functioning as a cell/drug delivery vehicle. In this contribution, a new gelatin hydrogel with dual-enzymatic cross-linking of horseradish peroxidase (HRP) and galactose oxidase (GalOx) was developed, and the therapeutic effect of this hydrogel encapsulated with bone mesenchymal stem cells (BMSC) in dermal wound healing was investigated. This hydrogel possesses a quick gelation process within 5 min, a high water content, and a uniform three-dimensional (3D) porous network. The 3D cell culture study indicated that gelatin hydrogel matrix of HRP(5U):GalOx(1U) or HRP(2U):GalOx(1U) could provide a friendly 3D microenvironment for supporting the survival, proliferation, and spread of mouse bone mesenchymal stem cells (BMSC) with negligible cytotoxicity. Hematoxylin and eosin staining test suggested that this hydrogel has superior histocompatibility and minimized immune response in vivo. Furthermore, wound-healing studies on a C57 mouse model of excised wound demonstrated that BMSC-laden gelatin hydrogel could significantly accelerate the wound closure as compared to other groups. These data suggest that this dual-enzymatically cross-linked gelatin hydrogel loaded with BMSC has a great potential in wound healing and other tissue-regeneration applications.