Preparation and in vitro bioactivity of hydroxyapatite/solgel glass biphasic material

Hydroxyapatite/solgel glass biphasic material has been obtained in order to improve the bioactivity of the hydroxyapatite (OHAp). A mixture of stoichiometric OHAp and the precursor gel of a solgel glass, with nominal composition in mol% CaO-26, SiO2-70, P2O5-4, has been prepared. The amounts of components used have been selected to obtain a final relationship for OHAp/solgel glass of 60/40 on heating. Two different thermal treatments have been used: (i) 700°C, temperature of solgel glass stabilisation and (ii) 1000°C, lower temperature of hydroxyapatite sintering. The bioactivity of the resulting materials has been examined in vitro by immersion in simulated body fluid at 37°C. The results obtained show that both materials are bioactive. The apatite-like layer grown is greater for the new materials than for the OHAp and the solgel glass themselves.