Enzymatically Crosslinkable Hyaluronic Acid-Gelatin Hybrid Hydrogels as Potential Bioinks for Tissue Regeneration

Hydrogels that mimic the composition and properties of the extracellular matrix have attracted great attention as potential polymeric scaffolds for tissue engineering applications. In this study, an injectable hydrogel composed of hyaluronic acid and gelatin was developed via the oxidative coupling reaction using horseradish peroxidase (HRP). The hydrogel was prepared by mixing two phenol-conjugated polymer solutions, hyaluronic acid-tyramine (HA-TA) and gelatin-hydroxyphenyl propionic acid (GH), in the presence of HRP and hydrogen peroxide (H202). The gelation rate and mechanical properties of composite hydrogel were controlled by adjusting the HRP and H202 concentrations, respectively Compared to the pure HA-TA hydrogels, the stability and cellular behaviors of composite hydrogel improved significantly In addition, the injectable hydrogel system showed good performance in 3D printing with high cell viability after one day of printing. The results suggest that enzymatically crosslinked HA-TA and GH hybrid (HA-TA/GH) composite of HA-TA and GH hydrogel has the potential as a material for tissue engineering and 3D printing biofabrication.