Induction of bioactivity on silicone elastomer by simultaneous irradiation of oxygen cluster and monomer ion beams

Silicone elastomer substrates were irradiated with acceleration voltages ranging from 3 to 9 kV and doses ranging from 1 x 10(14) to 2.5 x 10(15) ions cm(-2) by the simultaneous use of oxygen cluster and monomer (O(2) CM) ion beams, and then soaking in CaCl(2) solution. The apatite-forming ability of the substrates was examined using a metastable calcium phosphate solution that had 1.5 times the ion concentrations of normal simulated body fluid (1.5SBF). Silicon oxide clusters (SiO(x)) were formed at the silicone elastomer surfaces and the hydrophilicity of the substrates was remarkably improved by the irradiation. The irradiated silicone elastomer substrates formed apatite in 1.5SBF, whereas unirradiated ones did not. These results suggest that irradiation using O(2) CM ion beams is effective for inducing an apatite-forming ability on silicone elastomer substrates.