【作者】 孙达；

【导师】 姚芳莲；

【作者基本信息】 天津大学 ， 材料化学工程， 2012， 硕士

【摘要】 水凝胶是一种亲水的三维聚合物网络，它可以吸收大量水，其物理性质接近于软组织。水凝胶有着与细胞外基质极其相似的结构与特点，具有良好的生物相容性和生物降解性。因此，水凝胶在组织工程、药物释放等领域都获得了极大的关注。光交联作为一种构建水凝胶的常见方式，其反应条件温和，副产物少，反应过程容易控制，反应效率高，是构建水凝胶的良好选择。本文拟以水溶性壳聚糖衍生物O-羧甲基壳聚糖（CMCS）为水溶性大分子基质，以叠氮基团的光耦合反应为交联机理构建水凝胶，旨在使得到的水凝胶不仅具有可注射原位凝胶的性质，还具有pH敏感性。由于CMCS上含有羧基，因此，为了避免自交联的产生，本文提出了新的CMCS改性方案，即先制备对叠氮苯甲酸的活化酯，再将活化酯与CMCS上的氨基反应得到叠氮化羧甲基壳聚糖（AZ-CMCS）。合成过程中对产物都进行了红外光谱（FT-IR）、核磁共振谱图（1H-NMR）的表征。应用流变学的手段对AZ-CMCS水凝胶的交联过程进行了跟踪，并对水凝胶的湿态强度进行了考察。本文将AZ-CMCS水凝胶制成了二维薄膜和三维支架，分别考察了它们的理化性能和细胞相容性。结果表明，利用对叠氮苯甲酸活化酯实现CMCS的叠氮化反应，可以有效避免CMCS的自交联，条件容易控制。AZ-CMCS可以在短时间完成交联，得到的凝胶具有较好的湿态强度。AZ-CMCS水凝胶具有良好的pH响应性、良好的药物控释性能、低细胞毒性，是一种有潜力的生物医用材料。更多还原

【Abstract】 Hydrogels are networks with certain three dimensional structures, which aremade up of hydrophilic polymers that are crosslinked to form water insolublehydrogels. Today, hydrogels are widely applied in many fields. Due to their highlystructural and characteristic similarity to extracellular matrix, hydrogels receivedremarkable interest in the field of medicine and tissue engineering. Photo-crosslinkingreaction provides an effective and mild crosslinking process which involves in mildreaction conditions, minimum byproduct formation and controlling flexibility.Therefore, photo-crosslinking is a good choice for building hydrogels.In this paper, injectable hydrogels made from azidophenyl carboxymethylchitosan derivative (AZ-CMCS) were prepared. The conjugation of azido groups tocarboxymethyl chitosan chains were realized through a two step procedure. Toconfirm the conjugation, methods of1H NMR and FT-IR were employed. To evaluatethe photo sensitivity and mechanical properties of AZ-CMCS system, a rheologicalmethod was utilized with the help of small amplitude oscillatory shear under differentconditions. To evaluate the pH sensitivity, equilibrium swelling degree was examinedunder a wide range of pH values. At the same time, a drug release system was set upusing BSA as model drug under different pH values. Furthermore, AZ-CMCShydrogels were made into2-D membrane and3-D scaffolds. Their properties wereevaluated too.Results showed the success of conjugation of azido groups. At the same time,AZ-CMCS hydrogels can be good drug carries and can act as injectable gels dealingwith severe situations. AZ-CMCS hydrogels have a promising future in the field oftissue engineering and biomedicine.更多还原