Mechanism of incorporation of zinc into hydroxyapatite

• Published in: Acta biomaterialia Vol. 6; no. 6; pp. 2289 - 2293
• Main Authors: Matsunaga, Katsuyuki, Murata, Hidenobu, Mizoguchi, Teruyasu, Nakahira, Atsushi
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2010
• Subjects: Bone Substitutes - chemistry; Computer Simulation; Crystallization - methods; Defect complex; Durapatite - chemistry; First principles calculation; Formation energy; Materials Testing; Models, Chemical; Solution pH; X-ray absorption spectrum; Zinc - chemistry; Formation energy; First principles calculation; Defect complex; Solution pH; X-ray absorption spectrum
• ISSN: 1742-7061; 1878-7568
• DOI: 10.1016/j.actbio.2009.11.029

The atomic level mechanism of incorporation of Zn 2+ into hydroxyapatite (HAp), which is a potential dopant to promote bone formation, was investigated, based on first principles total energy calculations and experimental X-ray absorption near edge structure (XANES) analyses. It was found that Zn 2+-doped HAp tends to have a Ca-deficient chemical composition and substitutional Zn 2+ ions are associated with a defect complex with a Ca 2+ vacancy and two charge compensating protons. Moreover, first principles calculations demonstrated that Zn 2+ incorporation into HAp can take place by occupying the Ca 2+ vacancy of the defect complex. The Ca 2+ vacancy complex is not only the origin of the calcium deficiency in HAp, but also plays a key role in the uptake of trace elements during mineralization.