Abstract: Objective To study the biocompatibility of zinc-modified CaSiO3 bioceramic coating in vitro, and to provide experimental basis of its clinical application. Methods The physical characteristic of the coating and the concentration of differentions extracted from the coating were detected. Then the extract was used in MC3T3-E1 cells culture with different concentrations for cellular morphological observation, including the relative growth rate measured by MTT and the apoptosis rates detected by flow cytometry. Hemolysis ratio of the coating was also detected. Results Calcium, Silicon, Zinc ion concentrations of the coating's extract were significantly increased after immersion for 72 hours. All cells cultured with different proportions of diluent showed normal cellular morphology. Cells cultured in group 3.125% and 6.25% had larger quantity, higher relative increment rate and lower apoptosis rate, compared to positive control group (complete medium). Alone with the increasing concentrations, mild inhibition to the cells and increasing apoptosis rate were observed. The hemolysis rate of the coating's extract detected by hemolysis test was 0.5%. Conclusion The Zinc-modified CaSiO3 bioceramic coating with non-cytotoxicity and good biocompatibility has the biological basis of surface modification for bone implants and other biological material.

Key words: Zinc-modified CaSiO3 bioceramic coating, Cytotoxicity, Apoptosis, Biocompatibility, Bone implants