Effects of Heat Treatment on Phase Formation in Cytocompatible Sulphate-Containing Tricalcium Phosphate Materials

Powders based on β-tricalcium phosphate (β-TCP) containing sulphate groups at up to 12.0 mol.% were synthesised by chemical precipitation from aqueous solutions. The obtained materials were characterised by X-ray phase analysis, Fourier transform infrared spectroscopy, measurement of specific surface area, scanning electron microscopy, energy dispersive analysis, synchronous thermal analysis, mass spectra investigations and biological assays. It was established that during the synthesis, the obtained materials lose the sulphate groups in the course of heat treatment at 900 or 1200 °C. These groups stabilise low-temperature β-TCP, but when introduced at a high concentration, the sulphate groups contribute to the formation of hydroxyapatite during the heat treatment. Specific surface area of the powders proved to be in the range 81.7–96.5 m2/g. Results of biological assays showed cytocompatibility of both pure β-TCP and samples of sulphate-containing β-TCP. Additionally, matrix properties in the culture of MG-63 cells were revealed in all samples. Thus, the obtained materials are promising for biomedical applications.