title: Chemical characterization of hydroxyapatite obtained by wet chemistry in the presence of V, Co, and Cu ions.
abstract: A model system for the precipitation of hydroxyapatite (HA) from saturated solutions at basic pH was utilized to investigate the effects of V, Co, and Cu ions on crystallography and stoichiometry of the produced apatites. X-ray diffraction (XRD) was applied to analyze phase composition and crystallinity of powders obtained with different metal ion concentrations and annealed at different sintering temperatures. This procedure used the temperature-dependent phase transitions and decompositions of calcium phosphates to analyze the particular influences of the metal ions on apatite mineralization. Comparative XRD measurements showed that all metal ion species reduced crystallinity and crystallite size of the produced apatites. Furthermore the transformation of amorphous calcium phosphate (ACP) to HA was partially inhibited, as was deduced from the formation of α-tricalcium phosphate (α-TCP) peaks in XRD patterns of the heated powders as well as from the reduced intensity of the OH stretch vibration in FTIR spectra. The thermally induced formation of β-TCP indicated a significantly reduced Ca/P ratio as compared to stoichiometric HA. This effect was more pronounced with rising metal ion content. In addition, the appearance of metal oxides in the XRD patterns of samples heated to higher temperatures indicated the incorporation of metal ions in the precipitated apatites. Peak shifts showed that both the apatitic as well as the β-TCP phase apparently had incorporated metal ions.
authors.affiliation: Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, 97070 Würzburg, Germany. claus.moseke@fmz.uni-wuerzburg.de
authors.forename: Claus
authors.initials: C
authors.lastname: Moseke
authors.forename: Michael
authors.initials: M
authors.lastname: Gelinsky
authors.forename: Jürgen
authors.initials: J
authors.lastname: Groll
authors.forename: Uwe
authors.initials: U
authors.lastname: Gbureck
mesh_terms: D002118:Calcium / Q000032:analysis; D011232:Chemical Precipitation; D003035:Cobalt / Q000032:analysis*; D003300:Copper / Q000032:analysis*; D017886:Durapatite / Q000737:chemistry*; D007477:Ions; D008903:Minerals / Q000737:chemistry; D011208:Powders; D017550:Spectroscopy, Fourier Transform Infrared; D014639:Vanadium / Q000032:analysis*; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D007477:Ions; D008903:Minerals; D011208:Powders; D014639:Vanadium; D014867:Water; D003035:Cobalt; D003300:Copper; D017886:Durapatite; D002118:Calcium
keywords: Amorphous calcium phosphate; Apatitic phase; Mineralization; Tricalcium phosphate