Study of the influence of K+, Mg2+, SO4(2-) and CO3(2-) ions in the biomimetic crystallization of amorphous calcium phosphate (ACP) and conversion into octacalcium phosphate (OCP)

Abstract

The crystallization of hydroxyapatite (HA) in aqueous solution can be described by the mechanism ACP -> OCP -> HA. In this work, it was studied the influence of K+, Mg2+, SO4(2-) and CO3(2-) ions in the formation of ACP and in its conversion to OCP, using biomimetic coatings on metallic substrates of commercially pure titanium (Ti c.p.). The results showed that Mg2+ and CO3(2-) ions favored both the formation of ACP and its conversion to OCP. Differently, K+ and SO4(2-) ions did not influence the formation of ACP and, consequently, interfered in the conversion to OCP.

biomimetic coating; amorphous calcium phosphate; octacalcium phosphate