TOWARDS UNDERSTANDING INTERACTIONS BETWEEN APATITE SURFACES AND CARBOXYLATE LIGANDS AT THE ATOMIC LEVEL

Abstract

In order to gain better understanding of the interaction between apatite and organic species in engineered and/or biological, systems, we have studied the effects of four organic ligands, acetate, malonate, citrate and EDTA, on the supersaturation, with respect to calcium and phosphate, required for the onset of precipitation in aqueous solutions at pH 7, 25°C and 0.1M ionic strength. Organic ligands may influence both the supersaturation in solution and the crystallinity of the precipitating (hydroxyl)apatite. The ligands with two or more carboxyl groups appear to cause an increase in the supersaturation required for precipitation, and this is interpreted as an inhibitory effect by these ligands. Citrate is the most efficient inhibitor.