Molecular simulation of protein adsorption and desorption on hydroxyapatite surfaces

Protein adsorption and desorption on material surfaces play a key role in the biocompatibility of medical implants, biomineralization and protein separation. In this report, the adsorption and desorption behavior of the 10th type III module of fibronectin (FN-III(10)) with different orientations on hydroxyapatite (HAP) (001) surface were systematically studied by molecular dynamics (MD) and steered MD simulations. These studies show that the electrostatic energy plays a dominant role in the interaction between the model protein and the HAP surface. The values of the interaction energy not only relates to the number of adsorbed sites but also the type. The charged -COO(-) and -NH(3)(+) are the strongest groups that interact with the surface, while other groups like charged guanido group, neutral amino and hydroxyl groups have considerable interactions with the surface. The effects of these groups on interaction energy were quantitatively investigated.