Synthesis, characterization, and in-vitro cytocompatibility of amorphous β-tri-calcium magnesium phosphate ceramics

Biphasic mixtures of crystalline β-tricalcium magnesium phosphate (β-TCMP) and an amorphous calcium magnesium phosphate have been synthesized and reported to support enhanced hMSC differentiation in comparison to β-tricalcium phosphate (β-TCP) due to the release of increased amounts of bioactive ions. In the current study, completely amorphous β-TCMP has been synthesized which is capable of releasing increased amounts of Mg2 + and PO43 − ions, rather than a biphasic mixture as earlier reported. The amorphous phase formed was observed to crystallize between temperatures of 400-600 °C. The scaffolds prepared with amorphous β-TCMP were capable of supporting enhanced hMSC proliferation and differentiation in comparison to commercially available β-TCP. However, a similar gene expression of mature osteoblast markers, OCN and COL-1, in comparison to biphasic β-TCMP was observed. To further study the role of Mg2 + and PO43 − ions in regulating hMSC osteogenic differentiation, the capability of hMSCs to mineralize in growth media supplemented with Mg2 + and PO43 − ions was studied. Interestingly, 5 mM PO43 − supported mineralization while the addition of 5 mM Mg2 + to 5 mM PO43 − inhibited mineralization. It was therefore concluded that the release of Ca2 + ions from β-TCMP scaffolds also plays a role in regulating osteogenic differentiation on these scaffolds and it is noted that further work is required to more accurately determine the exact role of Mg2 + in regulating hMSC osteogenic differentiation.