【作者】 张爱华；

【导师】 姚康德；

【作者基本信息】 天津大学 ， 材料学， 2006， 硕士

【摘要】 组织工程的典型方法是在外源性的细胞外基质(ECMs)中种植细胞组成结构物,在生物反应器中培养扩增,在体外形成新组织后植入患者体内,与组织整合构建新的功能组织。因此,组织工程采用的外源性ECMs模拟天然组织的ECMs分子的功能。这种外源性ECMs就是由生物相容性良好和可生物降解的生物材料制备的复合材料。设计外源性ECMs的最佳方法就是仿生,即模仿天然组织中ECMs分子的结构与功能,将天然ECMs作为支架使细胞聚集而构建组织,控制组织结构并调控细胞表型。本论文从仿生角度出发,用化学交联的方法制备了壳聚糖/明胶/果胶水凝胶,并考察了其理化性能。该水凝胶的压缩强度在0.05-0.4MPa之间,并随着壳聚糖的分子量、果胶的含量和明胶的存在而变化。在PBS模拟体液中,由于壳聚糖分子量,果胶含量等因素的影响其降解速度也有所不同。其含水量可在20~80(g水/g聚合物)范围内变化,而增大水凝胶的交联度或溶液浓度会导致含水量的降低。在水凝胶的基础了,本实验采用了延流法制备了壳聚糖/明胶/果胶薄膜,并进行了下列测试:接触角实验证明果胶的加入提高了壳聚糖/明胶基材料薄膜表面的亲水性;XPS光电子能谱对壳聚糖/明胶/果胶复合薄膜的表面进行分析,证实果胶的加入使薄膜羧基和羟基含量增加;力学测试表明,壳聚糖/明胶/果胶复合薄膜干态拉伸强度可达80MPa左右,湿态情况下薄膜强度降低但柔韧性增加。另外,本实验还采用冷冻干燥技术制备了壳聚糖/明胶/果胶三维支架,和壳聚糖/明胶支架相比,壳聚糖/明胶/果胶支架无论是吸水率还是保水率都有明显的提高,然而拉伸强度明显下降,同时断裂伸长率则增加明显,且体外降解速度要稍慢一些。为了考察该生物材料的生物相容性,本实验利用体外培养L929细胞来考察细胞的壳聚糖/明胶/果胶薄膜和支架的生物相容性。实验结果表明,壳聚糖/明胶/果胶薄膜和支架具有良好的生物相容性。这些结果都说明了果胶是一种生物相容性良好的生物材料,它的加入提高了复合材料的性能,为其在生物医学领域提供了潜在的应用前景。更多还原

【Abstract】 Tissue engineering utilizes the theories and methods of life sciences and engineering sciences, researching and developing new clinic substitute for human tissue and apparatus. Its typical method is seeding cells in the artificial extracellar matrices (ECMs) to form cells/artificial ECMs constructs. Here the manual ECMs are three-dimensional biomaterial scaffolds with excellent biocompatibility. The functions of biomaterial scaffolds act as analogues to the natural ECMs found in tissues, which provide information for cells expressing their functions, e.g. adhesion, proliferation, differention etc. Therefore, the aim for biomaterial scaffolds design is to mimic the natural ECMs, from the compositions to the microstructure.In this paper, the chitosan/gelatin/pectin hydrogel was fabricated and the physicochemical properties of hydrogel was studied. The compressive strength of the hydrogel was between 0.05 and 0.4 MPa, and the influences of molecular weight (M.W.) of chitosan and the content of pectin and gelatin on the degradation and water content of the hydrogel were investigated.Based on the fabrication of the hydrogel, the chitosan/ gelatin/ pectin membrane was prepared by solution casting method. Incorporating pectin could improve the hydrophility of the membrane, and enhance the carboxyl group content on the surface. Its maximum value of tensile strength was about 80 MPa in dry-state, while dropped down in wet state, and the flexibility of the membrane increased in wet state. The adhesion and proliferation of L929 cells cultured on chitosan/ gelatin/ pectin membranes were higher than that of the tissue culture plate. Meanwhile, the properties of chitosan/ gelatin/ pectin scaffold prepared by freeze-drying method were investigated. The water uptake and retention abilities, the rate of degradation and the break ratio of the chitosan/ gelatin/ pectin scaffold were increased compared with chitosan/ gelatin scaffold, and the tensile strength was decreased. L929 cells could adhere on chitosan/ gelatin/ pectin scaffolds and proliferate to form cell/scaffold construction.The results showed that chitosan/ gelatin/ pectin composite biomaterials providing a microenvironment appropriate for cells, which can be a potential choice for tissue engineering in the future. Although this is a preliminary study for chitosan/ gelatin/ pectin biomaterials in tissue engineering, data will be helpful for future work in tissue更多还原