title: Mechanism of incorporation of zinc into hydroxyapatite.
abstract: 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.
authors: Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501, Japan. k.matsunaga@materials.mbox.media.kyoto-u.ac.jp
authors: Katsuyuki
authors: K
authors: Matsunaga
authors: Hidenobu
authors: H
authors: Murata
authors: Teruyasu
authors: T
authors: Mizoguchi
authors: Atsushi
authors: A
authors: Nakahira
mesh_terms: D018786:Bone Substitutes / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods; D017886:Durapatite / Q000737:chemistry*; D008422:Materials Testing; D008956:Models, Chemical; D015032:Zinc / Q000737:chemistry*
chemical_list: D018786:Bone Substitutes; D017886:Durapatite; D015032:Zinc