Biological activity of a SiO2–CaO–P2O5 sol–gel glass highlighted by PIXE–RBS methods

Abstract

It is proposed in this study to observe the influence of P2O5 on the formation of the apatite-like layer in a bioactive glass via a complete PIXE characterization. A glass in the SiO2–CaO–P2O5 ternary system was elaborated by sol–gel processing. Glass samples were soaked in biological fluids for periods up to 10 days. The surface changes were characterized by a micro-analytical technique of particle induced X-ray emission (PIXE) associated to Rutherford backscattering spectroscopy (RBS), in which multi-elemental distributions are efficiently analyzed. Elemental maps of major and trace elements were obtained at a micrometer scale and revealed the bone bonding ability of the material. A calcium phosphate-rich layer containing magnesium appears a few days after the interaction. We demonstrate that the presence of phosphorus in the material has an impact on the development and the formation rate of the bone-like apatite layer. Indeed, the Ca/P atomic ratio at the glass/biological fluids interface is closer to the nominal value of pure apatite compared to P2O5-free glasses. It would permit, in vivo, an improved chemical bond between the biomaterials and bone.