Comparison study on the solution-based surface biomodification of titanium: Surface characteristics and cell biocompatibility

In order to improve the surface biocompatibility of titanium, many techniques have been used for surface biological modification of titanium. In this paper, the surface modification based on solution, including acid etching (AC), alkaline and heat treatment (AH) and micro-arc oxidation (MAO), were used to modify the surface of titanium. The surface physical properties and chemical property and the relatively biocompatibility were investigated in order to find out the difference between different methods. The results showed that the AC treated surface exhibited micro-porous structure with the highest roughness and a pore size of less than 2 μm, AH-treatment provided with a smooth and nano-scale porous structure, and MAO produced a surface with interconnected macro-porous structure with spherical pores. Meanwhile, different methods also change the surface chemical composition, in which titanium and titanium oxide were mainly formed in the surface, sodium titanate gel and rutile were formed on the AH-treated surface and anatase and rutile were formed on the MAO-treated surface. In vitro test results have shown that the MAO treated sample exhibited more conductive to the formation of hydroxyapatite and the growth of bone cell due to rough and macro-porous rutile and anatase while AC treatment had limit influence on the surface activity. It was suggested that MAO processing could be more promising for surface modification of titanium.