Enhanced tissue adhesiveness of injectable gelatin hydrogels through dual catalytic activity of horseradish peroxidase.

Development of bioadhesives with tunable mechanical strength, high adhesiveness, biocompatibility, and injectability is greatly desirable in all surgeries to replace or complement the sutures and staples. Herein, the dual catalytic activity of horseradish peroxidase is exploited to in situ form the hydroxyphenyl propionic acid-gelatin/thiolated gelatin (GH/GS) adhesive hydrogels including two alternative crosslinks (phenol-phenol and disulfide bonds) with fast gelation (few seconds - several minutes) and improved physicochemical properties. Their elastic moduli increase from 6.7 to 10.3 kPa by adding GS polymer that leads to the better stability of GH/GS hydrogels than GH ones. GH/GS adhesive strength is respectively 6.5-fold and 15.8-fold higher than GH-only and fibrin glue that is due to additional disulfide linkages between hydrogels and tissues. Moreover, in vitro cell study with human dermal fibroblast showed the cell-compatibility of GH/GS hydrogels. Taken together, GH/GS hydrogels can be considered as promising potential adhesive materials for various biomedical applications.