Magnesium Oxide-Assisted Dual-Cross-Linking Bio-Multifunctional Hydrogels for Wound Repair during Full-Thickness Skin Injuries

Full-thickness skin injuries have always been an intricate problem in clinical treatment. The application of biomaterials provides an artificial matrix for the recruitment of cells and deposition of extracellular matrix to accelerate wound healing. For the recovery of full-thickness skin defects, the double cross-linking of MgO-catechol and Schiff's base bonds are used as part of the gel-forming mechanism, and a bio-multifunctional hydrogel (CCOD-MgO) is prepared by adding MgO to catechol-modified chitosan (CHI-C) and oxidized dextran (ODex). The CCOD-MgO demonstrates high tissue adhesion, excellent self-repairing, hemostasis function, and low swelling rate. With the addition of MgO and catechol chelation, the adhesion strength of CCOD-MgO is about 35 kpa, which is much greater than fibrin glue. Moreover, the CCOD-MgO has better antibacterial properties than CHI-C/ODex hydrogel (CCOD) due to the synergy of chitosan and MgO in vitro. Accordingly, the CCOD-MgO can protect the wounds from infection and accelerate the healing speed of the epidermis in full-thickness cutaneous defect and burn model in vivo. These results demonstrate that the CCOD-MgO would be a promising therapeutic strategy in full-thickness skin injuries for clinical therapies.