Pourreza, E., Alshemary, A. Z., Yilmaz, B., Rad, R. M., Tezcaner, A., and Evis, Z. (2017). Strontium and fluorine co-doped biphasic calcium phosphate: characterization and in vitro cytocompatibility analysis. Biomedical Physics & Engineering Express, 3(4), 045004. DOI: 10.1088/2057-1976/aa768c

Strontium (Sr²⁺) and fluoride (F⁻) ions are known to play an important role in bone and tooth metabolism. In this work, we prepare biphasic calcium phosphate (BCP) bioceramics co-doped with different fractions of Sr²⁺ and F⁻ ions to investigate the impact of dopant on the crystal structure and biological properties of BCP bioceramics. The materials were successfully synthesized using a wet precipitation method, followed by sintering at 1100 °C for 1 h. The sintered materials were characterized using x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). XRD analysis revealed that the BCP bioceramics were composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), along with calcium oxide (CaO) as impurity. Furthermore, the percentage of β-TCP tended to increase with an increase in the Sr²⁺ ion concentration. The lattice parameters of HA phase expanded along with incorporation of Sr²⁺ and F⁻ ions. The morphology of the yielding materials demonstrated that the incorporation of Sr²⁺ and F⁻ ions caused a decrease in the grain size. The Vickers hardness (HV) test showed that hardness values increased with increasing Sr²⁺ concentrations. In vitro cell culture tests were performed with human osteogenic sarcoma (Saos-2) cell line. Saos-2 cells attached and proliferated faster on Sr/F-BCP materials compared to pure BCP, showing that Sr/F-BCP materials were cytocompatible.