Absorption Spectra and Bioactivity Behavior of Gamma Irradiated CeO2-Doped Bioglasses

The synthesis and characterization of some bioglasses based on Hench’s Bioglass® 45S5 with additions of CeO2 (1.0, 2.0, or 3.0%) have been carried out. Two objectives have been focused upon; first, the effect of successive ionizing gamma irradiation on the undoped and CeO2-doped bioglass samples has been evaluated with the aim of justifying the role of the rare earth oxide CeO2 on gamma irradiation. The second objective was directed to test the bioactivity of such prepared CeO2-doped samples after soaking for 1 month in a simulated body fluid at 37 °C. The results indicate that the additions of CeO2 suppress, to a marked extent, the generation of radiation induced defects especially in the visible region. The bioactivity results show that the studied CeO2-doped bioglass samples gave rise to a calcium phosphate surface layer upon immersion in a simulated body fluid for 1 month at 37 °C and the bioactivity extent was almost identical in the CeO2 doping interval limit (1 → 3% CeO2) to that of the undoped base Hench’s Bioglass. The presence of both Ce3+ and Ce4+ ions were confirmed by optical absorption spectra. Electron spin resonance (ESR) studies of gamma irradiated CeO2-doped glasses indicate and confirm the dominance of Ce4+ in the bioglass compositions and its transformation to Ce3+ by high gamma irradiation.