Physico-Chemical Characterization and In Vitro Biological Evaluation of Pure SiHA for Bone Tissue Engineering Application

Studies about silicon-substituted hydroxyapatites exhibit several shortcomings that leave unanswered questions regarding the properties and subsequent biological outcomes generated by this biomaterial. Firstly, samples characterization is often incomplete, meaning that phase purity on the pellet surface is not assured. In fact, ceramic materials used in literature that are claimed to be pure are actually polluted through second phase as superficial polymerized silicate. In this study, we have successfully synthesized a phase-pure silicon hydroxyapatite powder Ca10(PO4)5.5(SiO4)0.5(OH)1.5 (Si0.5HA) compressed this powder into pellets, sintered them, and evaluated the biological response of osteoblast cells (C3H10 line) seeded on the pellet surface. Besides, the solubility in aqueous media of HA and Si0.5HA pellets were determined through "static" experiments. These tests attempt to provide a comprehensive picture of the cellular response to the SiHA material, in order to determine the mechanism by which Si evokes the improved in vitro biological outcomes described in the literature. Results revealed first an equivalent solubility of Si0.5HA and HA pellets, and second that cells do not react favourably to the pure SiHA surface