Phase transformation from hydroxyapatite to the secondary bone mineral, whitlockite

• DOI: 10.1039/c4tb01793e
• Publication Date: 2014-12-19T11:45:17Z
• Authors: Hae Lin Jang; Hye Kyoung Lee; Kyoungsuk Jin; Hyo-Yong Ahn; Hye-Eun Lee; Ki Tae Nam
• Keywords: Whitlockite

Whitlockite (WH: Ca18Mg2(HPO4)2(PO4)12) is the second most abundant mineral in hard tissues, but its precipitation mechanism or role body system poorly understood. Here, using a newly discovered synthetic method for WH, we investigated kinetic of WH under physiologically similar conditions, excluding any effects toxic ions. Based on systematically classified stages process monitored transformation calcium phosphate phases from neutral pH to acidic with addition H3PO4. The study revealed that at 70 °C, hydroxyapatite (HAP: Ca10(PO4)6(OH)2) transforms into dicalcium dihydrate (DCPD: CaHPO4·2H2O) and then presence Mg2+ ions as decreases. involves multiple intermediates, stability which depends cation (Ca Mg) activities solution pH. stable compound below 4.2, whereas HAP around We also found ions, are known block growth HAP, can play key formation. This provides new insight interplay biologically important compounds.