Self-cross-linked carboxymethyl chitosan/polyethylene glycol hydrogel containing bioactive peptide accelerates bacterial-infected wound healing.

Bacterial infection significantly delays wound healing and leads to chronic or non-healing wounds. Development of wound dressings against bacterial-infected wounds is urgently needed. Herein, a self-cross-linked carboxymethyl chitosan/polyethylene glycol hydrogel (CMCS-PEG-P) containing bioactive peptide YIAEDAER (Tyr-Ile-Ala-Glu-Asp-Ala-Glu-Arg) was prepared. The dynamic Schiff-base reaction between carboxymethyl chitosan and dialdehyde polyethylene glycol endowed the hydrogel with good injectable and self-healing properties. Biocompatibility studies revealed that hydrogel CMCS-PEG-P exhibited low cytotoxicity and hemolysis ratio. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) clearance rate was determined to be 57.5 %, and the antibacterial efficiency against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was 91.0 % and 52.9 %, respectively. In vivo biological studies revealed that hydrogel CMCS-PEG-P could promote wound healing in a bacterial-infected skin defect rat model, and the remained wound area on day 14 was only 3.6 %. The wound tissues exhibited a reduced inflammatory response, along with newly formed blood vessels and hair follicles. The expression of inflammatory- and vascular-related factors significantly changed. Our results indicated that hydrogel CMCS-PEG-P should be a promising biomaterial for bacterial-infected wound healing.