[Study of relationship between (Ca+Zn)/P of pure titanium surface coating and biological activity of osteoblasts].

Purpose: To study osteoblast (MC3T3-E1 cells) adhesion, proliferation and differentiation activity on the surface of pure titanium with different (Ca+Zn)/P ratios, and determine Ca, P, Zn contents offering best biological activity on pure titanium surface.

Methods: In the micro-arc oxidation electrolyte, Ca, P with a certain concentration, and 5 different concentrations of Zn (0, 0.01, 0.03,0.04, and 0.06 mol/L) were added, which made the mole ratio of Ca and P element close to the ratio of hydroxyapatite. (Ca+Zn)/P ratio of bioactive coating on 5 different pure titanium material surfaces were prepared, which named S0 and S1, S2, S3 and S4 group, respectively. The surface elements, existence form, (Ca+Zn)/P ratio and surface morphology were analyzed by XPS and SEM; MC3T3-E1 cells adhesion, proliferation and differentiation cultured on the material surface were analyzed by SEM, MTT method and ALP activity assay.

Results: The data was analyzed with SPSS13.0 software package. With the increase of Zn content in the electrolyte, (Ca+Zn)/P ratios were 2.94, 2.64 2.71, 2.87 and 2.72 in S0-S4 group, respectively. (Ca+Zn)/P ratio was maximal in S3 group and decreased in S4 group. MC3T3-E1 cell adhesion, proliferation and differentiation capacity on material surface of 5 groups changed in the following order: 3>S4>S2>S1>S0, with significant differences among 5 groups (P<0.05).

Conclusions: Coating with different concentrations of Ca, P, Zn on pure titanium surface by micro-arc oxidation technique, the adhesion, proliferation and differentiation ability of osteoblast increase as (Ca+Zn)/P ratio increase, and cell biological activity is the best when the (Ca+Zn)/P ratio reached 2.87.