Synthesis and Properties of Manganese-Containing Calcium Phosphate Materials

We have studied manganese-containing calcium phosphates differing in manganese content and phase composition. At a manganese content of 0.15 wt %, the whitlockite content is ~90 wt % and the calcium pyrophosphate content is ~10 wt %. Increasing the manganese content to 1.49 wt % reduces the whitlockite content to ~70 wt % and increases the calcium pyrophosphate content to ~30 wt %. IR spectroscopy results show that the samples calcined at 400°C have the apatite structure, whereas raising the calcination temperature to 900°C leads to the formation of the whitlockite structure and calcium pyrophosphate. Active sintering begins in the range 920–1050°C. Raising the firing temperature to 1200°C leads to the formation of a densely sintered structure, with melted regions and an average grain size from 15 to 25 μm. With increasing manganese content, the grain size of the ceramics decreases. Our results on cytotoxic properties demonstrate that the samples are not cytotoxic and maintain cell proliferation and spreading. The cytotoxicity of the samples is insensitive to the calcium pyrophosphate and manganese concentrations. The powders and ceramics prepared in this study can be used as key components of novel materials for bone tissue engineering.