Bioactive glass-ceramic synthesis using nano and normal silica: a comparative study

Abstract

Bioactive glass-ceramics are very promising materials for soft and hard tissue repair due to their high biocompatibility and bioactivity. The bioactive glass-ceramics (NSGC) containing (38-X)normal-SiO2-28CaO-18Al2O3-12CaF2-4P2O5-Xnano-SiO2 (mol%) (where X = 0, 19, and 38) system were synthesized using melt-quench method. The thermal behaviors were assessed by differential thermal analysis (DTA). The glass transition temperature (Tg) was high in the case of a mixture of 19 mol% normal silica and 19 mol% nano-silica. However, it was less with 38 mol%, either normal silica-containing or nano-silica-containing samples. As the quantity of nano-silica increases, the crystallization peak temperature (Tp) was increased. The X-ray diffractometer (XRD) result showed that the fluorapatite (FA) (Ca5(PO4)3F), mullite (M) (3Al2O3.2SiO2), and wollastonite (W) (CaSiO3) had the main crystalline phases for all the three batches. The crystals were needle and irregular shaped in all sintered specimens, as shown in a scanning electron microscope (SEM). They also showed the indications of surface cracks in case of high sintering temperature. Energy-dispersive X-ray spectroscopy (EDX) analysis showed the specimen’s elemental composition before and after the immersion in synthetic body fluid (SBF) solution. Fourier transform infrared (FTIR) spectra showed the characteristic peaks for Si–O–Si, Si–O–Ca, C–O stretching, O–H bending vibration, carbonate, and phosphate groups. The transmission electron microscope (TEM) images confirmed that the nanoparticles (2.58–8.15 nm) were present in the prepared glass-ceramics. The hydroxycarbonate apatite (HCA) layer was developed after 28 days of immersing in the modified SBF. The addition of nano-SiO2 in the specimens showed an increase in Vickers hardness, density, and acid-base resistivity.