Role of ZnO additions on the β/α phase relation in TCP based materials: Phase stability, properties, dissolution and biological response

Guided by the need to manufacture smart biomaterials, capable to replace and regenerate the mineral component of the bone, with optimized mechanical performance and bioresoption rate under physiological conditions, modified synthetic Zinc doped monophasic and/or biphasic β/α-tricalcium phosphate, Znc-Ca3-x(PO4)2 (Zn-TCP), dense bioceramics with different phase proportions and microstructures were synthesized by solid state sintering process.The compositions studied, ranging from 0.125 to 1.000 wt% ZnO were formulated in the Ca3(PO4)2-Zn3(PO4)2 subsystem of the ternary ZnO-CaO-P2O5 system. The design and control of compositions and processing conditions, enabled to fulfill the requirement in which Zn2+ was incorporated in solid solution in the TCP structure. Consequently, biomaterials with controlled porosity, density, phase proportion and microstructural distribution of α/β-TCP polymorphs were developed.The effect of ZnO content on the final properties was discussed and an improvement in relation to pure TCP samples was obtained. The influence of the surface physico-chemical characteristics on the mechanical performance and “in vitro” solubility in SBF was also studied. In addition “in vitro” biocompatibility was evaluated using MG-63 human osteoblast cells, obtaining synthetic Zn-TCP based biomaterials with improved cell-material interaction.