Horseradish peroxidase-catalyzed hydrogelation of fish gelatin with tunable mechanical properties and biocompatibility

Horseradish peroxidase-catalyzed injectable gelatin hydrogels have attracted much attention in various biomedical fields because of their processability, biodegradability, and excellent biocompatibility in promoting cell adhesion and proliferation. However, gelatin derivatives are mainly obtained from mammalian sources (porcine, bovine) with thermal gelation at room temperature, leading to the potential problems in biofabrication applications. Here, we introduce a novel fish gelatin derivative that can be easily dissolved and cross-linked at room temperature by horseradish peroxidase. This system provides thermally stable fish gelatin hydrogels with tunable mechanical and biological properties, comparable to porcine gelatin hydrogels. The properties (gelation time, stiffness, degradation rate) of hydrogels prepared from fish gelatin-hydroxyphenyl propionic acid (FGH) are controllable for suitable applications. Moreover, FGH hydrogels allow human dermal fibroblast cells to adhere, proliferate, and produce the extracellular components. These results suggest horseradish peroxidase-cross-linked FGH as potential hydrogel matrices that can be used as an alternative for mammalian gelatin hydrogels in various biomedical applications.