巯基化壳聚糖/明胶的制备研究

仿生杂化构建可注射水凝胶支架是制备组织工程材料的一条有效途径，而天然聚合物的改性即成为其前提条件。本文以巯基乙酸和4-丁巯内酯为反应试剂采用均相反应法制备了巯基化天然聚合物衍生物。结果表明，利用壳聚糖和明胶上的氨基等活性基团，可采用不同途径对它们进行巯基化改性；在水溶性碳二亚胺的活化作用下巯基乙酸的羧基与壳聚糖的氨基形成酰胺键，从而将活性巯基引入到壳聚糖中，但大部分被氧化；随着贮存时间的延长，各改性物中的巯基含量逐渐降低，因此需将改性物保存于低温惰性环境中，以保持其反应活性。

Preparation and Characterization of Thiolated Chitosan and Gelatin

From the biomimetic point of view, development of hybrid injectable hydrogels might be an effective strategy in constitution of tissue engineering materials. In this paper, thiolated chitosan and gelatin were synthesized by using thioglycolic acid or 4-butyrothiolactone that allowed homogeneous modification without sharp decrease of polymer properties. XPS analysis confirmed the formation of amide bond between the primary amino groups of the chitosan and the carboxylic group of thioglycolic acid, however the attached mercapto groups were oxidized mostly. In addition, a significant decreasing in the mercapto group contents was observed at usual store condition. Therefore, thiolated polymer derivatives ought to be stored at relatively low temperature under nitrogen gas in order to prevent from air oxidation.