Synthesis and in vitro characterization of cerium oxide mixed calcium oxy fluoro borophosphate bioactive glasses by means of spectroscopic studies

The main objective of this study is to achieve Ce substituted hydroxy apatite (HAp) deposition on the surface of the bio-active glasses which is more affective in antibacterial activity. Calcium oxy fluoro borophosphate glasses (with BaO as modifier) doped with different concentrations of Ce2O3 were prepared by melt quenching techniques. In vitro bioactivity studies were performed by soaking the samples in simulated body fluid (SBF) for about 30 days. The XRD and SEM studies have revealed the deposition of cerium substituted crystalline HAp coating on the surface of the post immersed glasses. The formation of HAp layer is further confirmed by IR and Raman spectral studies. The possible site preference of cerium ions in the HAp layer has been discussed using the results of above mentioned studies. The information regarding dependence of the magnitude of HAp layer developed on the concentration of Ce2O3 dopant is obtained by degradation studies viz., weight loss of the samples and the variation of pH of the residual solutions. The analysis of the results of degradability together with X-ray diffraction (XRD), Infrared (IR), Raman and optical absorption spectra indicated the increasing magnitude of Ce-HAp with the concentration of Ce2O3. Some of the characterization studies have also pointed out the co-presence of Ce ions in Ce4+ oxidation state along with Ce3+ state in the glass samples. The simultaneous presence of cerium ions in these two states in the crystalline HAp layer is predicted to be more useful in promoting the antibacterial activity of the glasses.