Activation of Hydroxyapatite Crystal Growth on the Surface of Biomimetic Synthetic Apatites through Electrical Polarization

A series of synthetic apatites bulk samples, characterized by different atomic substitutions were polarized by field of 1 and 2 kV·cm-1 at 300 °C. The thermally stimulated depolarization currents (TSDC) were measured and the stored electric charge density evaluated. The recent development in the synthesis of non-stoichiometric HA powders, whose chemical composition resembles that of the natural bone, is promising for the realization of improved biomimetic implants for bone substitution; therefore, electrical polarization applied on the ceramic pieces could further enhance the already strong bioactivity of these materials. The depolarization processes in the various material were evaluated by the Arrhenius’ method and related with the corresponding chemical features; finally, SEM observations of some polarized samples immersed in SBF at 37 °C revealed a wide growth of HA particles within a few days in all the investigated materials.