Molecular dynamics simulations of the adsorption of amino acids on the hydroxyapatite {100}-water interface

Abstract

The understanding of interfaces and interaction of organic molecules and inorganic materials are the important issues in biomineralization. Experimentally, it has been found that amino acids (AA) can regulate the morphology of hydroxyapatite (HAP) crystals significantly. In this study, molecular dynamics simulation is employed to investigate the detailed adsorption behavior of polar, ionic, and hydrophobic AA on the {100} face of HAP at the atomic level. The results indicate that various AA are adsorbed on the HAP crystal surface mainly by amino and carboxylate groups at the specific sites. Multiple interaction points are found for polar and ionic AA. The adsorbed AA molecules occupy the Ca and P sites of the HAP surfaces which may inhibit and regulate the HAP growth. The adsorbed amino acid layer can also change the interfacial hydration layer and influence the transportation of ions in and out of HAP, which may be another strategy of biological control in biomineralization.

Keywords

hydroxyapatite (HAP) / adsorption / amino acid (AA) / interfacial structure