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

Abstract

Abstract A glass-ceramic in the SiO2-K2O-CaO-P2O5 quaternary system was prepared by substituting the Na2O component with K2O to avoid Na2Ca2Si3O9 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 mm. 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 CaSiO3 and K2CaSiO4 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.

Keywords

• bioactive glass-ceramic
• carbonated hydroxyapatite
• bioactivity
• foam replication
• polyurethane foam
• crystallization
• biodegradability