Preparation and in vitro apatite-forming ability of hydroxyapatite and β-wollastonite composite materials

This paper provides a one-step method of preparation of the ceramic powders, containing various amounts of hydroxyapatite (HA) and β-wollastonite (WT), based on the salt coprecipitation and subsequent thermal treatment of the synthesis products at 1000 °C. Aqueous solutions of Ca(OH)2, H3PO4 and Na2SiO3 were used as precursors of Ca10(PO4)6(OH)2 and β-CaSiO3, as a minimal amount of by-product is formed during such an interaction of reagents. Variation of the concentration of the initial reagents allows the preparation of ceramic powders containing from 0 to 100 wt% of apatite. All composites were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), laser diffraction analysis and an adsorption method (BET). Degradability of composite powders was analyzed in the Tris-HCl buffer solution. The apatite-forming ability of synthetic composites was investigated by soaking composite ceramics in a simulated body fluid (SBF). The results that were obtained reveal an increase in the dissolution rate of powders with wollastonite addition. Soaking of the composite ceramics in SBF leads to the formation of a bone-like apatite spherical particle layer on their surfaces, which become thicker while the content of β-СаSiO3 in the samples increases.