Effect of different polypeptide modification methods on properties of micro-arc oxidation coatings covering pure titanium / 中国组织工程研究

ABSTRACT

BACKGROUND:It can be theoretical y speculated that the combination of titanium, micro-arc oxidation coating and arginine-glycin-aspartic acid (RGD) polypeptide wil show better mechanical and biological properties. OBJECTIVE:To observe the microstructure and cellproliferation of the titanium and micro-arc oxidation coatings modified with RGD polypeptide by different modification methods. METHODS:Ninety specimens of pure titanium and micro-arc oxidation coatings were divided into three groups, with 30 specimens in each group. The first 30 specimens were pure titanium physical y decorated with RGD polypeptide only. The other two groups of specimens were physical and chemical coupling adsorption RGD polypeptide micro-arc oxidation samples, respectively. The fluorescence microscope was used to observe the effects and amounts of grafting RGD polypeptide on each sample. Content of the RGD polypeptide on the surface of the specimens were measured by X-ray photoelectron spectroscopy. The mouse bone marrow stromal cells were cultured on the surfaces of three groups samples, and the adhesion and proliferation of the cells cultured for 3 hours, 12 hours, 24 hours and 3 days were observed by optical microscope respectively. RESULTS AND CONCLUSION:There were green fluorescence spots, with varying size and amount, on the surface of specimens in three groups. In the unit field of view, the fluorescence was the strongest in chemical coupling adsorption RGD polypeptide micro-arc oxidation samples, indicating that these specimens were grafted with many polypeptides. In physical coupling adsorption RGD polypeptide micro-arc oxidation samples, smal amount of polypeptides were found on the surface, and the content of the RGD polypeptide was the highest in chemical coupling adsorption RGD polypeptide micro-arc oxidation samples. No apparent cytotoxicity was observed in three groups. The cellproliferation was the best in chemical coupling adsorption RGD polypeptide micro-arc oxidation samples. Experimental findings suggest that, chemical coupling method can wel fix the RGD polypeptides on the surface of pure titanium samples containing micro-arc oxidation, without any cytotoxicity, which contribute to promote the cellgrowth and proliferation.