Schiff base formed functional hydrogel dressing via ε-poly-L-lysine modified chitosan and oxidized dextran with the incorporation of epigallocatechin-3-gallate

Hydrogel-based functional dressings for wound healing have garnered increasing attention due to their excellent hydrophilicity, adjustable mechanical properties, and superior biocompatibility. In this study, a composite hydrogel was facilely fabricated through the Schiff base reaction between ε-poly-L-lysine modified chitosan (CS-PL) and oxidized dextran (Odex). The formed hydrogel displayed the interconnected microstructure (100-200 μm), injectability, and adjustable mechanical properties. Macroscopic observation and alternating strain rheological analysis confirmed the good self-healing ability of the hydrogel. Furthermore, with the incorporation of epigallocatechin-3-gallate (EGCG), the composite hydrogel exhibited an improved reactive oxygen species (ROS) scavenging capability and good antibacterial activity against E. coli and S. aureus. The designed composite hydrogel dressings exhibited hemolysis rates of 0.75 ± 0.60% to 0.81 ± 0.31%, indicating their excellent hemocompatibility. Moreover, CCK-8 analysis and fluorescent images confirmed the excellent cytocompatibility of the hydrogels after co-culturing with NIH 3T3 cells for various periods. The above results offer a promising strategy for preparing functional hydrogel dressings via ε-poly-L-lysine modification on chitosan for wound healing applications.