Abstract: Objective:To cover the chitosan(CS) membrane on the biphasic calcium phosphate(BCP) scaffold prepared with 3D printing to prepare the composite scaffold,and to explore its application potentiality in bone tissue engineering. Methods:The BCP scaffold was prepared by 3D printing,and BCP/CS composite scaffold was prepared by covering CS membrane on it.The experiment was divided into control group (BCP scaffold group) and experimental group(BCP/CS scaffold group).The surface roughness and ultrastructures of the scaffolds in two groups were observed by atomic force microscope(AFM) and scanning electron microscope (SEM).The water absorption rates of scaffolds in two groups were measured by mean weighting method.The mouse anterior osteoblasts (MC3T3-E1) were cultured,at the same time,blank group was set up; the toxicity degrees of two kinds of stent extracts after co-cultured with the cells for different time (1,3,and 5d) were determined by CCK-8 method.The proliferation activities of cells at different time (1,3,5,and 7d) were detected by CCK-8 method after the cells were co-cultured with the scaffolds in two groups. Results:The AFM results showed that the surface roughness of the scaffolds in BCP/CS group was lower than that in BCP group.The SEM results showed that the average aperture of the scaffolds in BCP/CS group was 250-300 μm,and the average aperture in BCP group was 350-450 μm.The water absorption rates of scaffolds were(37.75±2.21)% in BCP/CS group and (32.00±2.43)% in BCP group;there was significant difference between two groups(P<0.05).According to the National standard (GB/T16886.5-2003),the toxicities of stent extracts in two groups in 1,3, and 5 d were 0,1, and 1 degree.The MC3T3-E1 cells could adhere and proliferate on the BCP/CS and BCP scaffolds,and the number of the cells in two groups was simply increased with the prolongation of time.The proliferation activity of the cells in BCP/CS group was significantly higher than those in BCP group and blank group (P<0.05) on the 7th day. Conclusion:BCP/CS composite scaffold has the characteristics of bone tissue engineering scaffold material without cytotoxicity and can improve the cell proliferation ability.It has the potential as scaffold of bone tissue engineering.

Key words: 3D printing, bone tissue engineering, biphasic calcium phosphate, chitosan membrane