Development of Mg-containing porous β-tricalcium phosphate scaffolds for bone repair

Apatitic tricalcium phosphate (ap-TCP) powders containing Mg were synthesized through wet chemical precipitation method from CaO and H3PO4, using MgO as the source of Mg substitution. The influence of small, close to bone-like amounts of Mg on the thermal stability and specific surface area (SSA) of as-synthesized ap-TCP powders was evaluated. The increase in Mg content up to 0.674 +/- 0.080 wt% promoted enlarging of SSA of the as-synthesized powders between 91.3 m(2)/g and 104.2 m(2)/g and the stabilization of the beta-tricalcium phosphate (beta-TCP) phase up to 1360 C. The effect of Mg substitution on porosity and microstructure was investigated. Interconnected porous Mg-containing beta-TCP scaffolds, with micro-, macroporous structures were developed by an in situ foaming of viscous mass of proper slurry prepared of the as-synthesized ap-TCP powders, using NH4HCO3 as a foaming agent, and subsequent sintering at 1150 degrees C for 2 h. The self-dissolution behavior in vitro was evaluated through soaking of scaffolds in SBF. The release of Ca and Mg ions from the 3D micro-, macroporous beta-TCP scaffolds containing various amounts of Mg was determined by a complexometric (EDTA) titration. The samples with increased Mg concentrations showed significantly enhanced Mgrelease rate in comparison to the samples with lower Mg substitution level. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.