Bioactive SiO2-K2O-CaO-P2O5 glass-ceramic scaffold prepared using polyurethane foam template

Abstract

A glass-ceramic in the SiO 2 -K 2 O-CaO-P 2 O 5 quaternary system was prepared by substituting the Na 2 O component with K 2 O to avoid Na 2 Ca 2 Si 3 O 9 formation upon thermal treatment since this phase decreases apatite formation kinetics on glass material. To form the glass-ceramic, a modified sol-gel method involving solution precipitation, followed by reagents encapsulation in citric acid was adopted to enable the use of sodium metasilicate as a cheap substitute for traditional alkoxysilane silica precursors. The foam replication method using polyurethane foam as a sacrificial template was used to obtain the scaffold, which on analysis gave a porosity of 92% and an average pore size of 36±6 m m. In vitro bioactivity evaluation in simulated body fluid for a maximum of 14 days indicated the formation of hydroxyapatite on the sample surface. Phase analysis showed that CaSiO 3 and K 2 CaSiO 4 crystals formed in the sintered sample as the main phases, which exhibited biodegradability in simulated body fluid (SBF). Therefore, economically-derived porous bioactive glass-ceramic scaffolds based on the current method (a simple process) are feasible.