title: Characterization and structural analysis of zinc-substituted hydroxyapatites.
abstract: The substitution of Zn in hydroxyapatite (HA) crystals was examined via comprehensive characterization techniques. Nanosized HA crystals were synthesized by the wet chemical method in aqueous solutions including various amounts of Zn ions. X-ray fluorescent spectroscopy was used to examine the amount of Zn in the HA precipitates. Scanning electron microscopy and high-resolution transmission electron microscopy were employed to examine the effects of Zn on the morphology and crystal size of the precipitates. Conventional powder X-ray diffraction and the Rietveld refinement method revealed the apatite lattice parameters and phase changes with the inclusion of Zn. The results indicated that Zn ions partially substituted for Ca ions in the apatite structure. They were not simply adsorbed on the apatite surface or in the amorphous phase. The precipitates maintained the apatite phase up to a Zn:(Zn+Ca) ratio of 15-20 mol.% in the solution. Pure HA was well crystallized and the crystals had regular shapes, whereas the Zn-substituted apatite crystals became irregular and formed agglomerates. The lattice parameters, a and c, decreased at a Zn:(Zn+Ca) ratio of 10 mol.%.
authors.affiliation: Department of Mechanical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Fuzeng
authors.initials: F
authors.lastname: Ren
authors.forename: Renlong
authors.initials: R
authors.lastname: Xin
authors.forename: Xiang
authors.initials: X
authors.lastname: Ge
authors.forename: Yang
authors.initials: Y
authors.lastname: Leng
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D003460:Crystallization / Q000379:methods; D006882:Hydroxyapatites / Q000737:chemistry*; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties; D023822:Tissue Engineering / Q000379:methods*; D015032:Zinc / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D006882:Hydroxyapatites; D015032:Zinc