The structure of amorphous calcium phosphate – a key intermediate in skeletal calcification

Research into the process of bone calcification has studied the transformation of calcium and phosphate ions into hydroxyapatite and has identified an intermediate amorphous phase. The precipitate known as Amorphous Calcium Phosphate (ACP) has the approximate composition Ca₃(PO₄)₂.nH₂O but its local structure is unknown. The only structural studies carried out were performed decades ago with lab based equipment. They theorised the material was composed of clusters in the order of 10Å, but this hypothesis has never been proven. Presented here are the initial results of a complete structural study of ACP using diffraction, absorption spectroscopy, small angle scattering and many more techniques. It is hoped that if the structure of this material can be fully understood then it will improve the understanding of the reaction between biomaterials and the body and hence aide in their development.