Abstract: Injectable hydrogels are widely employed as biomaterials for biomedical applications. In this study, disulfide-containing dextran-phloretic acid conjugates (Dex-SS-PA) are synthesized. In the presence of horseradish peroxidase, Dex-SS-PA solutions gelate to form bioreducible dextran-based hydrogels via the enzymatic crosslinking method. Physical and chemical properties of the hydrogels including gelation time, gel content and degradation properties are investigated. Live-dead assay and methyl thiazolyl tetrazolium assay are used to evaluate biocompatibility of the Dex-SS-PA hydrogels. It is shown that the higher the dextran molecular weight, degree of substitution of phloretic acid moieties and polymer concentrations, the shorter gelation time and the higher gel content of the hydrogels can be obtained. Besides, the Dex-SS-PA hydrogels are degradable under a bioreducible environment. Cellular viability of NIH 3T3 cells incorporated in the Dex-SS-PA hydrogels demonstrated that they reveal low cytotoxicity. The results indicate that the Dex-SS-PA hydrogels are potentially
useful in biomedical applications.

Key words: biodegradable, bioreduction-responsive, enzymatic crosslinking, injectable hydrogel