In vitro bioactivity, mechanical, and cell interaction of sodium chloride-added calcium sulfate–hydroxyapatite composite bone cements

Abstract

In this research, sodium chloride-added calcium sulfate–hydroxyapatite composite bone cements (0.70CaS–0.30HAP)/xNaCl were studied. Different wt% of NaCl (0, 1.5, and 2.5) were added to 0.70CaS–0.30HAP bone cement to investigate the setting time, injectability, washout resistance, phase evolution, physical properties, water absorption, microstructural, chemical analysis, mechanical strength, statistical analysis, in vitro apatite-forming ability, and in vitro cytotoxicity. With increasing NaCl, the initial setting time decreased to around 3.18 min. X-ray pattern revealed that all composite bone cement samples had mixed phases of CaS, HAP, brushite, gypsum, and NaCl. Water absorption and average grain size increased with increasing NaCl content. The densification and mechanical performances, including σ_c, σ_f, and E values, slightly decreased with increasing NaCl content, correlated with the increasing porosity value. This resulted in the production of a porous structure, which caused an excellent in vitro apatite-forming ability. The x = 2.5 sample showed good bioactivity, inducing the highest apatite mineralization ability in the SBF solution. Additionally, in vitro cell culture analysis showed above 94.12% cell viability against a high concentration (@ 200 μg mL⁻¹) for the x = 2.5 sample, revealing cytocompatibility. The obtained results indicated that the (0.70CaS–0.30HAP)/2.5NaCl composite bone cement, with good injectability, bioactivity, and cytocompatibility, are promising candidates for biomedical applications.