基于组织工程研究的可降解支架材料选择策略

Strategies to choose scaffold materials for tissue engineering

摘要:

目前，器官或组织移植是治疗器官衰竭或大范围组织缺损唯一长期有效的方法，但存在供体短缺、免疫排斥等问题。组织工程技术作为一种潜在的替代治疗方法，支架材料的选择是其中具有决定意义的组成部分。组织工程支架材料按其来源可分为天然及其改性修饰材料、人工合成与复合支架材料3种。组织工程目的就是修复临床上的病损组织或器官，并达到较理想的结构和功能的恢复。因此组织工程支架也必须从基本性质上具有一定的仿生化结构及功能，即“活”支架，这样才能彻底代替病损组织或器官。通过多种支架材料的优化组合 (即材料的复合)，对材料进行表面改性、制备工艺优化及添加细胞因子缓释微球等技术，模拟病损器官组织的特性及周围环境，有望打开组织工程的新局面。理想的组织工程支架应当以临床需要为根本目的，依靠材料学、分子生物学、工程学等多学科间的交叉研究，取各家之长，优化配比组合，达到仿生的目的。本课题组前期工作已经将骨髓间充质干细胞体外诱导分化为胆管上皮样细胞，并设计出左旋聚乳酸/聚己内酯共聚物 (PLCL) 胆道支架,内部混有包含生长因子的纳米缓释微球，供细胞因子的远期释放，支架内表面涂有基质胶/胶原混合层，且胶内加入bFGF、EGF，提供诱导因子的早期释放。将诱导细胞与PLCL胆道支架复合，制备组织工程胆管。文中综述了现存各类支架材料的研究状况，简单介绍了制备工艺、表面修饰等影响支架性能的因素，力求探索组织工程支架材料的选择策略。

Abstract:

Current therapies of organ failure or a wide range of tissue defect are often not ideal. Transplantation is the only effective way for long time survival. But it is hard to meet huge patients demands because of donor shortage, immune rejection and other problems. Tissue engineering could be a potential option. Choosing a suitable scaffold material is an essential part of it. According to different sources, tissue engineering scaffold materials could be divided into three types which are natural and its modified materials, artificial and composite ones. The purpose of tissue engineering scaffold is to repair the tissues or organs damage, so could reach the ideal recovery in its function and structure aspect. Therefore, tissue engineering scaffold should even be as close as much to the original tissue or organs in function and structure. We call it “organic scaffold” and thi+L8s strategy might be the drastic perfect substitute for the tissues or organs in concern. Optimized organization with each kind scaffold materials could make up for biomimetic structure and function of the tissue or organs. Scaffold material surface modification, optimized preparation procedure and cytosine sustained-release microsphere addition should be considered together. This strategy is expected to open new perspectives for tissue engineering. Multidisciplinary approach including material science, molecular biology, and engineering might find the most ideal tissue engineering scaffold. Using the strategy of drawing on each other strength and optimized organization with each kind scaffold material to prepare a multifunctional biomimetic tissue engineering scaffold might be a good method for choosing tissue engineering scaffold materials. Our research group had differentiated bone marrow mesenchymal stem cells into bile canaliculi like cells. We prepared poly(L-lactic acid)/poly(ε-caprolactone) biliary stent. The scaffold’s internal played a part in the long-term release of cytokines which mixed with sustained-release nano-microsphere containing growth factors. What’s more, the stent internal surface coated with glue/collagen matrix mixing layer containing bFGF and EGF so could supplying the early release of the two cytokines. Finally, combining the poly(L-lactic acid)/poly(ε-caprolactone) biliary stent with the induced cells was the last step for preparing tissue-engineered bile duct. This literature reviewed a variety of the existing tissue engineering scaffold materials and briefly introduced the impact factors on the characteristics of tissue engineering scaffold materials such as preparation procedure, surface modification of scaffold, and so on. We explored the choosing strategy of desired tissue engineering scaffold materials.