Hydrogels of dialdehyde starch and gelatin cross-linked with potential application as tissue adhesives

Invasive surgical methods are the current standard for hemostasis and wound closure. In recent years, injectable hydrogels prepared from natural biomacromolecules have shown promise as tissue adhesives to overcome their shortcomings due to their high hydrophilicity and biocompatibility, but the inherent properties of unmodified biomolecules remain a major challenge in their application. In this paper, a hydrogel (DS/Gel-CDH) with self-healing, injectable and adhesive functions was constructed by Schiff base crosslinking between carbonyl hydrazide modified gelatin (Gel-CDH) and dialdehyde starch (DS). The adhesion strength of the hydrogel (34.92 kPa) is much better than that of commercially available protein adhesives (17.44 kPa). In addition, Cytotoxicity and hemolysis tests showed that the hydrogel was non-cytotoxic (cell survival rate was 96.9 %) and could be used as biomaterial in contact with blood. The rats skin incision wound model further confirmed that this hydrogel can adhere to the wound and promote healing. H&E and MT staining showed no signs of toxicity in the tissue around the wound, and IL-6 and IL-1β staining showed no inflammatory reaction. It is proved that the hydrogel has good biocompatibility and degradability in vivo. The results indicate that the multifunctional the DS/Gel-CDH hydrogels are a promising and effective tissue adhesive material.