Enhancement in the induction heating efficacy of sol–gel derived SiO2–CaO–Na2O–P2O5 bioglass-ceramics by incorporating magnetite nanoparticles

Abstract

Magnetite (Fe₃O₄) nanoparticle (MNP)-substituted glass-ceramic (MSGC) powders with compositions of (45 − x)SiO₂–24.5CaO–24.5Na₂O–6P₂O₅–xFe₃O₄ (x = 5, 8, and 10 wt%) have been prepared by a sol–gel route by introducing Fe₃O₄ nanoparticles during the synthesis. The X-ray diffraction patterns of the as-prepared MSGC nanopowders revealed the presence of combeite (Na₂Ca₂Si₃O₉), magnetite, and sodium nitrate (NaNO₃) crystalline phases. Heat-treatment up to 700 °C for 1 h resulted in the complete dissolution of NaNO₃ along with partial conversion of magnetite into hematite (α-Fe₂O₃). Optimal heat-treatment of the MSGC powders at 550 °C for 1 h yielded the highest relative percentage of magnetite (without hematite) with some residual NaNO₃. The saturation magnetization and heat generation capacity of the MSGC fluids increased with an increase in the MNP content. The in vitro bioactivity of the MSGC pellets was evaluated by monitoring the pH and the formation of a hydroxyapatite surface layer upon immersion in modified simulated body fluid. Proliferation of MG-63 osteoblast cells indicated that all of the MSGC compositions were non-toxic and MSGC with 10 wt% MNPs exhibited extraordinarily high cell viability. The MSGC with 10 wt% MNPs demonstrated optimal characteristics in terms of cell viability, magnetic properties, and induction heating capacity, which surpass those of the commercial magnetic fluid FluidMag-CT employed in hyperthermia treatment.