【摘要】 目的改进制备工艺,提高几丁聚糖/甘油磷酸钠水凝胶(chitosan/glycerol phosphate,C/GP)的黏度,以期拓展其应用范围。方法采用改进的消毒方法,即将几丁聚糖单独进行高压蒸汽消毒,制备高黏度温敏性C/GP(high viscous C/GP,HV-C/GP)。并采用常规方法制备C/GP。Gemini流变仪动态检测HV-C/GP、C/GP流变学变化,评估黏度提高以后材料的初始黏度、胶凝温度和胶凝时间变化。将凝胶化的两种材料,放入PBS液中,于0、1、2、5、10和25d取出,干燥称重,计算失重率,比较两种材料的体外降解情况。采用扫描电镜观察两种材料的超微结构。结果脱乙酰度91%的C/GP初始黏度为1.81Pas,而HV-C/GP为17.24Pas,后者较前者提高了近10倍。C/GP的胶凝温度为37℃,HV-C/GP为34℃;在胶凝温度下,两者的胶凝时间约为5min。0.5mLHV-C/GP和C/GP凝胶化后第1天,失重率分别约为72.5%和55.4%,此后质量逐渐降低,至第25天分别为90.8%和78.2%。扫描电镜下两种材料均可以观察到多孔网络结构,C/GP孔径为50~100μm,HV-C/GP孔径为30~50μm,后者较前者明显缩小。结论通过改进消毒方法制备的HV-C/GP黏度明显提高,但温敏性变化不大;降解时间有所延长;扫描电镜观察可见多孔网络状结构,且孔径减小。更多还原

【Abstract】 Objective To increase the viscosity of chitosan/glycerol phosphate(C/GP)and to improve its prepara-tion technique in order to develop the application range of C/GP.Methods Chitosan was treated by high-pressure vaporsterilization in order to prepare high viscous C/GP(HV-C/GP)and prepare C/GP by standard methods.The rheologic changesof HV-C/GP and C/GP were detected dynamically by the Gemini rheometer.The initial solution viscosity,gelation temperatureand gelation time were evaluated after the viscosity of the materials were increased.Two gelation materials were placed into con-tinuous ow thermostated cells under the same condition and harvest them at predetermined time intervals,1st,2nd,5th,10thand 25th days,then they were dried,weighed and the mass loss rate was calculated.Ultrastructure of the freeze-dried sampleswas visualized by the scanning electron microscope.Results The initial viscosity of C/GP was 1.81 Pas and that of HV-C/GPwas 17.24 Pas.The latter one increased 10 times as well as the former one.The gelation temperature of C/GP was 37°C and thatof HV-C/GP was 34°C.There was no remarkable di erence in gelation time between them.The mass loss rate of HV-C/GP atrst day was 72.5%and at 25th days was 90.8%,while that of C/GP was 55.4%and 78.2%.Porous network structure was ob-served by the scanning electron microscope in both of them.The pore diameter of C/GP was 50-100 m and that of HV-C/GPwas 30-50 m,which was obviously smaller than the former.Conclusion The viscosity of HV-C/GP prepared by improvedtechnique obviously increases and the thermosensitivity has no signi cant changes.The degradation time of HV-C/GP in vitrolengthens.The micrographs show that the HV-C/GP gels are porous and the pore diameter are smaller than C/GP.更多还原