Amine Modification of Calcium Phosphates by Low-Pressure CH4/N2/He Plasma for Bone Regeneration

Abstract Calcium phosphates are promising materials for artificial bone but lack of satisfied osteogenic ability on their surfaces. In the present study, we applied a low-pressure plasma technology to chemically (amine) modify the surface of calcium phosphates (hydroxyapatite or beta-tricalcium phosphate) using a CH4/N2/He plasm gas mixture to improve their osteogenic ability. The CH4/N2/He plasma treatment produced a thin, stable amine-rich carbon polymer on the surface of the calcium phosphates, and enhanced hydrophilicity, deep infiltration of cells into porous calcium phosphates, cell adhesion and osteogenic differentiation on the surface of calcium phosphates. In a rat calvarial defect model, the CH4/N2/He plasma treatment afforded calcium phosphates a significant higher bone regeneration capacity. Together, these results suggest that surface modification of calcium phosphates with CH4/N2/He plasma might improve osteogenic ability of calcium phosphates in vitro and in vivo.