Composite monetite/amorphous calcium phosphate bone cement promotes bone regeneration

Monetite (MC) is a type of calcium phosphate cement (CPC). It has various morphologies, continuous degradation and absorption properties; however, its high porosity will affect its mechanical properties. There is minimal research on MC is immature. Amorphous calcium phosphate (ACP) is widely used and exhibits good biocompatibility; however, it is unstable. In this study, MC was combined with ACP at different weight ratios to form new types of bone cements. The mechanical properties, biocompatibility, and inductive ability for osteogenesis and osteoclasts of different MC/ACP composite bone cements were evaluated. The biocompatibility and effects on osteogenic and osteoclast differentiation of MC/ACP composite bone cements were investigated in vitro using mouse bone marrow mesenchymal stem cells (mBMMSCs) and mouse monocyte/macrophage cell line RAW 264.7. RAW 264.7 cells can differentiate into osteoclasts by osteoclast differentiation. The results indicated that the overall performance of the MC/ACP composite bone cement was better than that of the MC or ACP alone. Compared to the other groups, the biocompatibility of MC75 (75 wt% MC and 25 wt% ACP) was optimal; it was able to induce mBMMSCs osteogenesis to a greater extent. MC75 was the least favorable for the proliferation, migration, and differentiation of osteoclasts. The mechanical properties, setting time and injectability of MC75 meet clinical application requirements. This study demonstrated that MC75 is a promising bone cement for repairing bone defects.