中文摘要：

可注射水凝胶作为生物材料被广泛用于生物医学领域. 合成了含有二硫键的葡聚糖衍生物（Dex-SS-PA）, 使用辣根过氧化酶化学交联制备出新型的生物还原响应的可注射水凝胶. 系统研究了这些水凝胶的物理化学属性, 包括成胶时间、胶含量及降解性, 同时使用生死染色实验和噻唑蓝比色法实验评价了它们的细胞生物相容性. 研究结果表明, 葡聚糖的分子量越大、根皮酸的取代度越高、Dex-SS-PA 的浓度越大, 获得的水凝胶成胶时间越短、胶含量越高. 在还原环境中, Dex-SS-PA 水凝胶能够被降解. 此外, 这些水凝胶没有明显的细胞毒性. 因此, 这类新的水凝胶预示着较好的生物医学应用前景.

英文摘要：

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.