Control of bioactivity for silica gel by simple surface modification with calcium ion

In order to control the bioactivity of pure silica gel, its surface was modified with Ca ion and its apatite forming ability was investigated using simulated body fluid. Bulk type of silica gel which was surface modified with Ca ion was easily prepared by sol-gel method. Pure silica gel did not formed apatite on its surface, but the silica gel modified with 0.1 mole Ca solution formed bonelike apatite on its surface after soaking in SBF7.25 for 3 days. The induction period of apatite formation on the silica gel modified with 0.5mole Ca solution is faster than that of the silica gel modified with 0.1mole Ca solution. In can be seen from the results described in this study that bioactivity of the sol-gel derived silica gel can easily controlled by varying the concentration of Ca solution which are related with its dissolution rate of Ca ion into SBF when it was soaked in the SBF as well as implanted into body environment.