Regulation of calcium phosphate phase transition kinetics in aqueous solution via additives

Abstract

Additive-mediated regulation of calcium phosphate phase transitions is critical for synthesizing bone-like mineral structures in vitro. The main calcium phosphate phases involved in mineralization include amorphous calcium phosphate (ACP), dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), and hydroxyapatite (HAp). This paper reviews the role of additives in these phase transitions. Additives are often adsorbed onto calcium phosphate surfaces, inhibiting transitions from ACP, DCPD, and OCP to HAp. Additives can act as nucleation templates or reduce particle size, promoting the transition from ACP to HAp. The concentration and addition timing of additives significantly influence their role in the ACP-to-HAp transition. Surface energy, incorporation of additives, and interactions with ions in solution also play an important role in calcium phosphate phase transitions.