Sol-gel synthesis of a nanometric hydroxyapatite-silica composite

Abstract

Nanometric Hydroxyapatite-Silica (HASi) composite was prepared via the sol-gel technique. The obtained powders were heated in a microwave oven for 20 min at 180, 200, 220 and 230°C and in electric furnace at 600 and 700°C for 4 h. The X-ray diffraction patterns of the microwave heated powders have confirmed the presence of Hydroxyapatite (HA) nanoparticles together with the amorphous silica phase. However, the XRD patterns of furnace-heated powders have shown the presence of pure HA at 600°C and of HA along with β-TCP at 700°C. Moreover, acid dissolution experiments were conducted to determine the extent of the silica coating and its influence on the stability of HA at low pH. The bioactivity of the microwave-heated nanocomposite was assessed using SBF solution and it was found that all samples have shown an average bioactivity.