Synthesis, Osteoblast, and Osteoclast Viability of Amorphous and Crystalline Tri-Magnesium Phosphate

Magnesium phosphate implants may be used for bone void filling applications, potentially replacing traditionally studied bioceramics, which suffer from limited resorption and inferior mechanical properties compared to natural bone. In this study, amorphous and crystalline trimagnesium phosphates were synthesized and characterized utilizing a variety of analytical methods. In vitro solubility and cytotoxicity of the corresponding amorphous and crystalline phosphates were also analyzed. Amorphous magnesium phosphate was shown to be more soluble than the crystalline counterpart in vitro while inducing mineralization of an amorphous phosphate phase mimicking hydroxyapatite-type characteristic morphology on the substrate surface. The rapid mineralization of the amorphous magnesium phosphate was found to promote the proliferation and differentiation of osteoblast-like cells in comparison to the crystalline phase. Both magnesium phosphates hindered the differentiation of monocytes into osteoclasts. The combined effects of the spontaneous serum-mediated apatite-like mineralization, increased osteoblast differentiation and suspended osteoclast formation indicate that the amorphous magnesium phosphates may be promising bioactive materials for bone void repair applications.