Designing Self-Healing Hydrogels with Antibacterial Property Based on Host–Guest Interactions between Aminoazobenzene-Modified Gelatin and Polycyclodextrin for Prolonging the Shelf Life of Tyrosinase Enzyme

Here, a self-healing hydrogel was designed and synthesized to immobilize tyrosinase enzyme (Tyr), addressing the need for improved enzyme performance. The self-healing properties of the hydrogel ensured structural integrity, while its enzyme immobilization capability significantly enhanced enzyme stability and activity. The hydrogel was synthesized via host-guest interactions between polycyclodextrin (PCD) and aminoazobenzene-modified gelatin (Gel-AZO), and chemically cross-linked in the presence of glycidyl methacrylate-modified gelatin (GM-Gelatin) and acryloyloxyethyltrimethylammonium chloride (DAC) to form a dual-network structure. The immobilized enzyme retained 94.56% of the free enzyme's activity and remained stable under varying pH and temperatures, maintaining 70% activity at 70 °C. Reusability tests showed preserved enzymatic activity over six cycles. The hydrogel exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli, maintained cell viability above 80%, and showed hemolytic activity below 5%. These results highlight the potential applicability of this self-healing hydrogel in biomedical and industrial settings that require stable enzymatic performance.