Abstract: 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.

Key words: 3D printing, polydopamine, bone tissue engineering, bioceramics, biphasic calcium phosphate