基于聚乙烯醇制备仿生软骨组织工程支架

发布时间：2018-01-27 16:58

本文关键词： 聚乙烯醇卡拉胶生物活性定向支架组织工程　出处：《天津大学》2016年博士论文　论文类型：学位论文

【摘要】：组织工程支架的设计应该按照仿生原理,最大限度地模拟目标组织或器官的细胞外基质的组成、结构和功能,以达到修复创伤和重建功能的目的。天然关节软骨组织具有独特的结构,这与其功能性密切相关,本文结合组织仿生学理论,优化材料组成和性能,并对支架进行仿生设计和研究。具体研究内容如下:1.聚乙烯醇(PVA)水凝胶具有与天然关节软骨类似多孔结构和力学性能,适合于关节软骨修复的研究。但纯PVA水凝胶不仅缺乏细胞粘附性,而且成型过程中容易出现形貌皱缩的现象,严重限制了其在组织工程领域中的应用。本文通过加入天然多糖卡拉胶(CAR)组分,利用冰冻-融化循环技术得到了PVA与CAR的复合水凝胶(CP),结果表明所制得的CP水凝胶在冷冻干燥过程中具有抗皱缩性能,表现出良好的结构稳定性。同时,由于CAR组分对PVA结晶性产生影响,得到的复合材料内部结构相对疏松,明显提高了CP凝胶材料的孔径;2.对CP复合材料进行生物学评价,体外细胞实验结果表明CAR的加入可以显著提高PVA水凝胶的生物活性,促进细胞在材料上的粘附和增殖,并且能够维持细胞的良好表型;通过体外溶血实验以及巨噬细胞激活实验表明,CP复合材料不会引起溶血,保持很低的巨噬细胞激活率,具有潜在的体内应用前景。3.利用定向冰冻-融化循环技术,得到具有取向结构的PVA-CAR定向支架,仿生了天然软骨的组织结构,具有优异的理化性能。体外细胞实验表明,定向支架相对非定向支架,更有利于细胞的迁移和增殖,有效地提高了细胞在支架内部的均匀分布,保证支架结构的均匀稳定。同时,体内组织相容性实验结果表明支架的取向结构赋予其良好的渗透性,能够引导宿主细胞的长入和增殖,为新生组织提供适宜的生存环境,促进组织与支架之间的相互作用;4.以PVA和CAR为基体,添加无机组分羟基磷灰石(HA),制备了HA-CP复合支架材料,在优选支架材料理化性能基础上对其进行生物学性能评价,结果表明HA-CP支架表现出良好的细胞与组织相容性;在此基础上,采用渗透与定向冰冻-融化循环相结合的技术,得到OCP/HA-CP双层复合支架材料,其上层具有取向结构用于构架软骨层,下层为多孔结构用于构建骨层,模拟了关节软骨与软骨下骨的特点。提高渗透时间可以提高双层支架的界面结合强度,有效地防止上下层的分离,有希望解决以往因存在明显的界面而导致软骨与软骨下骨难以结合的问题。
[Abstract]:Tissue engineering scaffolds should be designed to maximize the composition, structure and function of the extracellular matrix of the target tissue or organ in accordance with the bionic principle. Natural articular cartilage has a unique structure, which is closely related to its function. In this paper, the material composition and properties are optimized based on tissue bionics theory. And the biomimetic design and study of the scaffold. The specific research contents are as follows: 1. Polyvinyl alcohol PVA) hydrogel has similar porous structure and mechanical properties to natural articular cartilage. It is suitable for the repair of articular cartilage, but the pure PVA hydrogel is not only lack of cell adhesion, but also prone to the appearance of shrinkage during the molding process. The application of Carrageenan in tissue engineering was severely restricted. In this paper, the natural polysaccharide carrageenan carrageenan (Carrageenan) component was added. The composite hydrogels of PVA and CAR were obtained by freezing and melting cycle technique. The results show that the prepared hydrogels have anti-shrinkage property during freeze-drying process. At the same time, due to the effect of CAR composition on the crystallinity of PVA, the internal structure of the composite is relatively loose, which obviously improves the pore size of CP gel material. 2. The biological evaluation of CP composite material in vitro showed that the addition of CAR could significantly improve the biological activity of PVA hydrogel and promote cell adhesion and proliferation on the material. And can maintain the good phenotype of cells; In vitro hemolysis test and macrophage activation test showed that CP composite did not cause hemolysis and maintained a very low rate of macrophage activation. The PVA-CAR scaffold with oriented structure was obtained by using the technique of directional freeze-thawing cycle, and the tissue structure of natural cartilage was simulated. 3. In vitro cell experiments show that the directional scaffold is more conducive to cell migration and proliferation than the non-directional scaffold and can effectively improve the uniform distribution of cells in the scaffold. At the same time, the results of in vivo histocompatibility experiment showed that the oriented structure of the scaffold has good permeability and can guide the growth and proliferation of host cells. To provide suitable living environment for newborn tissue and promote the interaction between tissue and scaffold. 4. HA-CP composite scaffolds were prepared by adding hydroxyapatite as inorganic component and PVA and CAR as matrix. The biological properties of HA-CP scaffolds were evaluated on the basis of physicochemical properties. The results showed that HA-CP scaffolds showed good cell and histocompatibility. On this basis, the OCP/HA-CP bilayer composite scaffold material was obtained by using the technique of osmosis and directional freeze-melting cycle. The upper layer of the composite scaffold has a oriented structure for the framework cartilage layer. The lower layer is a porous structure to construct the bone layer, which simulates the characteristics of articular cartilage and subchondral bone. Increasing the osmotic time can improve the interface bonding strength of the double-layer scaffold and effectively prevent the separation of the upper and lower layers. It is hopeful to solve the problem that cartilage and subchondral bone are difficult to combine because of obvious interface.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R318.08

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