Effect of varying phosphate content on the structure and properties of sol-gel derived SiO2-CaO-P2O5 bio-glass

Abstract

In this work, biocompatible glass (bioglass) particles were prepared by low temperature, acid catalysed sol-gel method. The effect of varying phosphate (P2O5) content (10, 15 and 20 mol %) in the sol-gel derived glass composition were studied. The sol-gel derived bioglass particles were compacted into cylindrical pellets via hydraulic press machine and sintered at 600°C for 3 hours. The bioglass particulates were analysed by x-ray fluorescence (XRF), Fourier Transformed Infrared (FTIR), X-Ray Diffraction (XRD) and nitrogen gas adsorption. Meanwhile, the sintered bioglass pellets were analysed by FTIR, XRD and FESEM-EDX. Furthermore, in vitro bioactivity analysis was performed by immersion in simulated body fluid (SBF) for 14 days. Bioglass particulates with high glassy phase, high surface area and high porosities were obtained for all compositions. Increasing of phosphate content to 20 mol% particularly reduced the porous characteristics of the bioglass particulates. Furthermore, leads to higher bridging oxygen (BO) atoms, higher amorphous silicate networks, lower glass crystallinity and higher number of phosphate crystallites within the amorphous glassy matrix. Increased to 20 mol% of phosphate also reduced the ability of the bioglass surface to induce carbonated apatite formation when immersed in simulated body fluid (SBF) solution.