Abstract: Objective: To explore whether zinc ions on the multiwalled carbon nanotubes/chitosan composite can promote proliferation and differentiation of osteoblast, and the appropriate concentration of zinc ion on the materials. Methods: The multiwalled carbon nanotubes/chitosan composites with different contents of zinc ions were prepared, and observed by scanning electron microscope. Thereinto, 0.2% zinc content of the composite was low-zinc group, 1% zinc content of the composite was medium-zinc group, 2.5% zinc content of the composite was high-zinc group, and the composite without zinc was control group. The MC3T3-E1 cells were seeded on surface of the four kinds of composites. Using MTT methods, alkaline phosphatase assay kit, ELISA, and laser scanning confocal microscope, cell proliferation, alkaline phosphatase activity, osteocalcin level, and cell morphology were detected. Results: Scanning electron microscope picture showed that the composite material had a large number of pore structure. The proliferation of cells at 24h, 48h and 72h in the medium-zinc group was higher than that in the control group (P<0.05), the low-zinc group was not significantly different from control group, and the high-zinc group was less than control group (P<0.05). Alkaline phosphatase activities at 24h, 48h, 72h in the medium-zinc group were higher than those in the control group (P<0.05), the low-zinc group was not significantly different from control group, and the high-zinc group was less than control group (P<0.05). Osteocalcin level at48h in the medium-zinc group was higher than that in the control group (P<0.05), the low-zinc group was not significantly different from control group, and the high-zinc group was less than control group (P<0.05). Conclusion: The middle-zinc-group composites was more favorable to the proliferation and differentiation of MC3T3-E1 cells.

Key words: Zinc , Tissue engineering bone, Proliferation, Differentiation