Hematin-conjugated gelatin as an effective catalyst for preparing biological hydrogels

Abstract

To mimic the function of HRP enzyme and improve the catalytic effectiveness of hematin in neutral media, a molecule was conjugated onto gelatin to overcome the solubility drawback of hematin. The obtained results have shown that hematin-conjugated gelatin (Ge–He) performed a catalytic peroxidase-like function that was more effective than that of free hematin. At a suitable conjugated amount, Ge–He showed superior catalytic efficiency in the oxidation reaction of guaiacol under neutral conditions as compared to other hematin-based biocatalysts. The activity of Ge–He exhibited higher stability under harsh conditions (higher concentration of H₂O₂) than natural HRP enzyme. When the Ge–He biocatalyst was applied in the preparation of hydrogels, the gelation time of phenolic gelatin (Gel–Tyr) was as rapid as that of HRP-mediated hydrogels. Furthermore, the Ge–He biocatalyst is highly compatible with cells, with 100% viability of human fibroblast cells in vitro. Therefore, the designed Ge–He provides feasible strategies for mimicking HRP enzyme for biomedical applications.