Fast in situ generated ε-polylysine-poly (ethylene glycol) hydrogels as tissue adhesives and hemostatic materials using an enzyme-catalyzed method

In this study, novel bio-inspired in situ hydrogels as tissue adhesives and hemostatic materials were designed and prepared based on ε-polylysine-grafted poly(ethylene glycol) and tyramine via enzymatic cross-linking. The enzymatic cross-linked method enabled fast gelation within seconds, which facilitated its therapeutic applications. By changing the cross-linking conditions, the storage modulus of the hydrogels could be tunable and the mechanical strength influenced the tissue adhesiveness of the hydrogels. Besides, the hydrogels showed fine network structures with appropriate pore sizes, which were thought to be a contributing factor to the strong adhesiveness. Benefiting from the strong mechanical properties and fine network structures, the ε-polylysine-grafted poly(ethylene glycol) and tyramine hydrogels exhibited superior wound-healing and hemostatic ability compared to conventional and commercially available medical materials. Moreover, indirect cytotoxicity assessment indicated that the ε-polylysine-grafted poly(ethylene glycol) and tyramine hydrogels were nontoxic to the L929 cell. These results demonstrated that the enzymatic cross-linked in situ ε-polylysine hydrogels hold high potential for tissue sealants and hemostatic materials.