Abstract
A solid surface usually makes clear interface against a biological system, such as cell and tissue; the interface works as a barrier for transportation of molecules and conduction of biofunction. Thus, to create unclear and graded interface at which molecules smoothly transport, both material and tissue are integrated together, and biofunctions are conducted, many researches have been performed. When titanium is implanted into bone, bone tissue forms on it faster and the bonding strength is clearly stronger than other metallic materials. Therefore, titanium shows the best hard tissue compatibility among metallic materials. Many surface treatment techniques are investigated to improve tissue compatibility of titanium, while most of them are for improving hard tissue compatibility. Commercialized surface modification techniques are mainly to form roughened or porous surfaces, while immobilization of biofunctional molecules is hardly commercialized at present. To increase the performance of a material, the characterization of the material itself and discussion on the relation between the biological reaction and property of the material, are mandatory. In addition, to commercialize the material, the evaluation of the safety, durability, and conservation of the material and the surface treated layer is essential.
