聚多巴胺涂层3D打印双相磷酸钙组织工程支架的制备及其评价

目的：在3D打印制备的双相磷酸钙（BCP）支架的表面进行聚多巴胺（PDA）涂层，构建成骨活性较高的新型骨组织工程支架，并对其应用潜力进行初步评价。方法：通过3D打印技术制备BCP生物陶瓷支架，将制备完成的组织工程支架在多巴胺溶液中浸泡，以使支架表面形成纳米级的PDA覆膜结构，无PDA涂层的支架为3DBCP组，有PDA涂层的支架为PDA-3DBCP组。利用扫描电子显微镜观察各组支架表面微观形貌，通过测定支架表面的水接触角表征材料的亲水性，采用比重法测定支架的孔隙度，万能试验机检测支架的机械强度，CCK-8方法检测支架上细胞的增殖活性。结果：与3DBCP组比较，PDA-3DBCP组支架表面水接触角明显缩小（t=5.06，P<0.05），支架孔隙度和机械强度差异无统计学意义（t=0.103，P>0.05；t=0.002，P>0.05）。将细胞接种至支架并进行1、3和5 d的复合培养，CCK-8法检测，随着培养时间的延长，2组细胞增殖活性逐渐升高，第5天时与3DBCP组比较，PDA-3DBCP组支架细胞增殖活性明显升高（t=39.3，P<0.05）。结论：PDA涂层的3D打印BCP多孔支架符合骨组织工程支架材料的表征，并且可以提高细胞的增殖能力，具备作为骨组织工程支架的潜力。

Preparation of polydopamine coated 3D printed biphasic calcium phosphate tissue engineering scaffold and its evaluation

Objective:To coat polydopamine (PDA) on the surface of biphasic calcium phosphate (BCP) scaffold prepared by 3D printing and construct a novel bone tissue engineering scaffold with high osteogenic activity,and to conduct a preliminary evaluation on its application potential. Methods:BCP bioceramic scaffolds were prepared by 3D printing technology, and then they were immersed in dopamine solution for a certain period to form a nanoscale PDA film structure on the surface.The PDA-free scaffolds were named 3DBCP group, and the PDA-coated scaffolds were named PDA-3DBCP group. Scanning electron microscope (SEM) was used to observe the surface topography of the scaffolds in each group; the hydrophilicity of the material was characterized by measuring the water contact angle of the scaffold surface; the scaffold porosity was determined by the specific gravity method, and the mechanical strength was tested by the universal testing machine; CCK-8 assay was adopted to detect the cell proliferation activity on the scaffold. Results:Compared with 3DBCP group, the surface water contact angle of the the scaffolds in PDA-3DBCP group was significantly reduced (t=5.06, P<0.05);there were no significant differences in the porosity and the mechanical strength between two groups(t=0.103, P>0.05; t=0.002, P>0.05).The cells were inoculated into the scaffolds and cultured for 1, 3 and 5 d;the CCK-8 assay results showed that the proliferation activities of the cells in two groups were gradually increased with the prolongation of the culture time. Furthermore, compared with 3DBCP group, the cell proliferation activity of the cells in PDA-3DBCP group on the 5th day was significantly increased (t=39.3, P<0.05). Conclusion:The PDA-coated 3D printed BCP porous scaffold has the advantages in characterization,it can improve the cell proliferation ability, which shows the potential as bone tissue engineering scaffolds.