Growth of bone like hydroxyapatite and cell viability studies on CeO2 doped CaO-P2O5-MgO-SiO2 bioceramics

The present study focuses on the study of influence of CeO2 substitution on the structural, in vitro bioactivity, degradation, osteoblasts proliferation, oxidative stress and cell apoptosis induction in the sol-gel derived 34SiO(2)center dot 8P(2)O(5)center dot 17MgO center dot xCeO(2).(41-x)CaO (x = 0, 0.5, 2.5 and 5 mol%) bioceramics. Zeta potential measurements were undertaken and it has shown two sign reversals with time when samples were immersed in simulated body fluid. This is mainly attributed to the adsorption of the cations from the samples and the second reversal is speculated to be due to the precipitation of the POi" from the body like fluids. Results revealed that samples containing high amounts of cerium decrease bioactivity by forming the cerium phosphate instead of hydroxyapatite on their surfaces. In spite of the decrease in growth rate of hydroxyapatite layer formation, it is observed that maximum protection towards the oxidative stress induced by hydrogen peroxide and apoptosis is favored for higher amounts of cerium-containing samples exhibiting maximum cell viability. Our results indicate that the "sol gel" synthesis technique promotes hydroxyapatite growth rate over conventional "melt quenching" route.