title: The uptake of titanium ions by hydroxyapatite particles-structural changes and possible mechanisms.
abstract: In order to understand the effect of titanium ions on the molecular structure of hydroxyapatite (HAp), HAp powders were incubated in solutions with different titanium concentrations. After incubation, the powders obtained were analysed using different techniques, namely X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS). The results suggest that, depending on the concentration of titanium in solution, two different mechanisms of interaction with HAp occur. For concentrations equal to or smaller than 200 ppm, the titanium uptake by the solid seems to be primarily due to incorporation in the lattice. For higher concentrations, a dissolution-precipitation process seems to occur, leading to formation of a titanium phosphate compound.
authors.affiliation: INEB-Instituto de Engenharia Biomédica, Laboratório de Biomateriais, Rua do Campo Alegre 823, Porto 4150-180, Portugal. cribeiro@ineb.up.pt
authors.forename: Cristina Castro
authors.initials: CC
authors.lastname: Ribeiro
authors.forename: Iain
authors.initials: I
authors.lastname: Gibson
authors.forename: Mário Adolfo
authors.initials: MA
authors.lastname: Barbosa
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D007477:Ions; D012996:Solutions / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014025:Titanium / Q000032:analysis / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D007477:Ions; D012996:Solutions; C036532:titanium phosphate; D017886:Durapatite; D014025:Titanium