超临界流体技术制备聚乳酸组织工程三维多孔支架实验研究

Experimental study on the preparation of three dimension polylactic acid tissue engineering porous scaffold based on supercritical fluid

理想三维支架的构建是组织工程化人工器官成功的前提条件。以聚乳酸为模型材料,二氯甲烷为溶剂,利用超临界流体诱导相分离过程制备具有外部三维立体结构和内部三维互通的组织工程支架,考察了过程制备的可行性,分析了操作参数如操作压力、温度和溶液浓度对孔的形态、结构和孔壁的影响。结果表明,利用超临界流体诱导相分离过程可成功制备孔径分布均匀、互通性好、孔隙率高的组织工程用三维多孔支架,且制备周期短,工艺简单。随操作压力、温度和溶液浓度的增加,支架孔径均逐渐减小。但过程中温度太低,压力或初始溶液浓度太高均会导致聚合物富相内聚乳酸的快速结晶析出从而形成由纳米级聚乳酸颗粒粘结在一起的支架孔壁。本实验范围内较优的操作参数为:高压釜压力10 MPa,温度45℃,溶液浓度20%(质量分数)。

Structuring of ideal three dimension （3D） porous scaffold is the prerequisite for the study success of tissue-engineered artificial organs. Tissue engineering scaffolds with 3D external stereoscopic structure and 3D internal interflow were prepared by supercritical fluid induced phase separation process with polylactic acid as model material and dichloromethane as solvent. The feasibility of this process was investigated. The influences of operation parameters such as operating pressure, operating temperature and solution concentration on the pore morphology, structure and the wall were analyzed. The results showed that the tissue engineering 3D porous scaffold with uniform pore diameters, good intercommunication and high porosity can be prepared suc-cessfully by supercritical fluid induced phase separation process characterized by short operating time and simple process. With the increase of operating pressure, operating temperature and solution concentration, the pore di-ameters decreases gradually. However, lower operating temperature, higher operating pressure and solution concentration results in a rapid precipitation of polylactic acid in the polymer rich phase which leads to specific pore walls composed of nano or micro-meters polylactic acid particles. In this experimental range, the optimal operating parameters is of operating pressure 10 MPa, the operating temperature 45°C and solution concentration 20wt %.