In vitro bioactivity evaluation of $\alpha$-calcium sulphate hemihydrate and bioactive glass composites for their potential use in bone regeneration

To combine the self-setting property of $\alpha$-calcium sulphate hemihydrate ($\alpha$-CSH) with the bioactive property of bioactive glass (BG), BG was added into $\alpha$-CSH to prepare $\alpha$-CSH/BG composites. The in vitro bioactivity and cytocompatibility of the $\alpha$-CSH/BG composites were assessed by soaking the composites in simulated body fluid (SBF) and co-culturing with the osteoblasts, respectively. Formation of a bone-like apatite layer on the composite surface was studied by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Variations in ionic concentration and pH of the SBF solution were detected. The incorporation of BG into $\alpha$-CSH, effectively compensated for the pH decrease caused by the dissolution of $\alpha$-CSH and the ion exchange. Osteoblast-like cells (MG63) were cultured on the samples, and the MTT results confirmed that the composites containing BG were more favourable for the proliferation of these cells. Hence, $\alpha$-CSH/BG composites might have great potential for the use as a bone regeneration material.