New Trends in Bioactive Glasses: The Importance of Mesostructure

A new generation templated mesoporous bioactive glasses (MBGs) with alkali oxide has been synthesized for biomedical applications with different compositions by sol-gel method. The sol-gel route involves the evaporation induced self assembly (EISA) process using non-ionic block copolymer as structure directing agent. In vitro bioactivity test on the obtained glasses after immersion in simulated body fluid has been carried out for various time durations. With the aid of four different glass systems, the role of calcium and phosphorus on in vitro bioactivity of silicate glasses has been investigated. Several analytical techniques have been used to characterize the MBG samples before and after soaking in the simulated body fluid (SBF) to establish correlation between composition, porosity and bioactivity. The quaternary glasses have been found to show rapid hydroxycarbonate apatite (HCA) formation and crystallization than ternary and binary glasses independent of Na2O/CaO content. Based on the obtained results, it has been suggested that the presence of phosphorous and calcium in the bioglass appreciably increases the rate of apatite crystallization.