单甲氧基聚乙二醇接枝壳聚糖温敏性水凝胶的制备及其性能表征

Preparation and Characterization of the Thermosensitive Hydrogei Composed of mPEG-grafted Chitosan

目的研究单甲氧基聚乙二醇接枝壳聚糖(mPEG-g-chitosan)温度敏感性水凝胶的制备方法,并对其理化性能进行测定。方法应用化学交联方法制备mPEG-g-chitosan共聚物;应用傅立叶红外光谱仪(FT-IR)测试样品的结构变化;应用热重分析仪(TGA)测试mPEG-g-chitosan共聚物的接枝率。将共聚物在PBS中溶胀制备成水凝胶溶液,应用流变仪测定其凝胶温度及时间。结果在一定范围内,mPEG与壳聚糖的接枝率与这二者的摩尔比率成正相关,与NaCNBH_3/mPEG的摩尔比率成负相关。mPEG-g-chitosan共聚物溶液开始形成凝胶的温度为25℃,在此温度下的凝胶时间约为16 min。凝胶强度随着温度的升高而增加。结论应用化学交联方法制备了具有良好性能的mPEG-g-chitosan共聚物水凝胶,该水凝胶可在常温或低温下呈液态溶胶,在体温时呈固态凝胶,为活性蛋白质类药物的安全参入和控释提供了适宜的载体。

Objective To study the preparation of thermosensitive hydrogel methoxy poly（ethylene glycol） grafted chitosan（mPEG-grafted chitosan） and its chemical and physical properties are to be determined. Methods A chemical cross-linking was used to synthesize mPEG-g-chitosan copolymer.The samples molecular changes were investigated by Fourier transform infrared spectroscopy（FT-IR）.The grafting ratio of the copolymers was surveyed and evaluated by thermogravimetric analyzers（TGA）.Hydrogel solution was prepared by making the copolymer dissolve in PBS,and gel temperature and time was examined by rheometer.Results The experimental results showed that the grafting rate increased with increase of the mPEG/chitosan,and decreased as NaCNBH_3/mPEG molar ratio increased within a certain range.Its sol-to-gel transition was at 25℃,and the gel time was about 16 minutes.The gel intensity increased with the increasing temperature.Conclusion The mPEG-g-chitosan copolymer hydrogels with good properties are prepared by chemical crosslinking method.The hydrogels are liquid sol at room or low temperature,and solid gel at body temperature,which provides a suitable carrier for the safe incorporation and controlled release of many bioactive protein drugs.