Characterization of an oxidized alginate-gelatin hydrogel incorporating a COS-salicylic acid conjugate for wound healing

[Display omitted] •This study was to conjugate the chitooligosaccharide (COS) with salicylic acid (SA).•SA was conjugated to COS backbone by using a free radical-induced grafting method.•The COS-SA conjugates were completely synthesized and improved antioxidant activity.•Hydrogel was to fabricate using oxidized alginate (OA) and gelatin (G) with COS-SA.•Hydrogel with COS-SA conjugate exhibited wound healing activity in a mouse model. In the present study, chitooligosaccharide (COS) and salicylic acid (SA) conjugates were synthesized using H2O2-induced grafting polymerization and oxidized alginate (OA) and gelatin hydrogels were fabricated using Schiff’s base reaction. To confirm the synthesis and improved activity of the COS-SA conjugates, polyphenol assays, ultraviolet absorbance, NMR, and antioxidant activity tests were all conducted. The results showed that the COS-SA conjugates were completely synthesized and improved antioxidant activity. OA was synthesized using a periodate method and a hydrogel was obtained at a mixed ratio of 3:7 via crosslinking between the aldehyde group of the OA and the amine groups of gelatin with COS-SA conjugates. In a cytotoxicity and wound healing model, the hydrogels with COS-SA conjugates did not exhibit cytotoxicity and exhibited wound healing activity in a mouse model. These results provide evidence that OA and gelatin hydrogels with a COS-SA conjugate can be successfully used for wound healing applications.