相分离法制备脂肪族聚酯及其复合纳米纤维支架

发布时间：2018-06-22 19:38

本文选题：聚乳酸 + 乙交酯-丙交酯共聚物　；参考：《北京化工大学》2010年硕士论文

【摘要】： 生物降解高分子已经被广泛的用于组织工程制备支架材料。为了模仿天然的细胞外基质,要求支架具有高的孔隙率,纤维直径在50-500纳米,且具有三维孔间结构。目前制备支架的方法有很多,如静电纺丝法、自组装技术、相分离技术等,但它们都存在各自的优缺点,为了弥补这些缺点可以采用多种方法相结合。相分离法制备纤维结构的过程为聚合物的溶解-冷凝-溶剂萃取-冷冻干燥,但聚合物能否纤维化的关键是聚合物溶液是否能形成凝胶。本论文首先采用相分离法和冷冻干燥技术相结合的方法制备了结晶性聚乳酸(PLLA)的纳米纤维支架,并研究了冷凝温度和浓度对纤维形貌的影响。发现：冷凝温度越低越有利于纤维化,但在同一冷凝温度下,能够发生纤维化的聚合物溶液有一个最佳的浓度范围。通过在聚乳酸中复合碳纳米管、石墨片、羟基磷灰石或-磷酸三钙等粒子,成功地制备了PLLA复合纳米纤维支架。无机粒子的复合改善了单纯PLLA纤维支架的力学性能和生物相容性。本研究还利用相分离法与致孔剂相结合的方法,以粒径为200-400微米的氯化钠或明胶球为致孔剂,制备了孔壁为纤维结构的大孔支架。实验结果表明,致孔剂的形态,大小直接影响纤维支架中孔的形貌。本文还采用相分离法,针对乙交酯-丙交酯共聚物(PLGA)的纳米纤维化开展了研究。主要考察了乙醇、丙酮和水三种非溶剂对PLGA75／5纳米纤维化的影响,最终确定以一定比例的THF／H2O混合溶剂为溶剂通过低温诱导PLGA溶液凝胶化,然后经过溶剂萃取和冷冻干燥,可获得PLGA纳米纤维化支架。研究结果表明,采用一定比例的溶剂和非溶剂混合,调节PLGA在其中的浊点和凝胶点,是使无定型PLGA通过相分离法实现纳米纤维化的有效途径。
[Abstract]:Biodegradable polymers have been widely used in tissue engineering to prepare scaffolds. In order to mimic the natural extracellular matrix, the scaffold must have high porosity, fiber diameter of 50-500 nm, and three-dimensional pore structure. At present, there are many methods for preparing scaffolds, such as electrostatic spinning, self-assembly, phase separation, etc., but they all have their own advantages and disadvantages, in order to remedy these shortcomings, we can use a variety of methods to combine. The process of preparing fiber structure by phase separation is dissolution-condensation solvent extraction-freeze-drying but the key to polymer fibrosis is whether the polymer solution can form gel. In this paper, the crystalline poly (lactic acid) (PLLA) nanofiber scaffolds were prepared by phase separation and freeze-drying techniques, and the effects of condensation temperature and concentration on the morphology of the fibers were studied. It is found that the lower the condensation temperature is, the more favorable the fibrosis is, but at the same condensation temperature, there is an optimum concentration range for the polymer solution which can produce fibrosis. The PLLA composite nanofiber scaffolds were successfully prepared through the preparation of carbon nanotubes, graphite sheets, hydroxyapatite or tricalcium phosphate in poly (lactic acid). The composite of inorganic particles improved the mechanical properties and biocompatibility of pure PLLA fiber scaffolds. In this study, macroporous scaffolds with fiber structure were prepared using sodium chloride or gelatin spheres of 200-400 micron diameter as pore inducers by combining phase separation method with pore-forming agent. The experimental results show that the morphology and size of the pore-forming agent directly affect the morphology of the pores in the fiber scaffold. The nano-fibrosis of glycolide-lactide copolymer (PLGA) was also studied by phase separation method. The effects of three non-solvents, ethanol, acetone and water, on PLGA 75 / 5 nano-fibrosis were investigated. The gelation of PLGA solution was induced by a certain proportion of THF / H _ 2O mixed solvent at low temperature, and then was extracted by solvent and freeze-dried. PLGA nanofibrosis scaffolds can be obtained. The results show that mixing a certain proportion of solvent and non-solvent and adjusting the cloud point and gel point of PLGA is an effective way to realize nano-fibrosis by phase separation of amorphous PLGA.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R318.08

【引证文献】