title: Characterization of hydroxyapatite by electron microscopy.
abstract: The obtention of hydroxyapatite (HAp) is reported using brushite (CaHPO4.2H2O) and the skeleton of a starfish (Mellita eduardobarrosoi sp. nov.), primarily composed of magnesian calcite ((Ca,Mg)CO3) as precursors. Stoichiometric amounts of both were reacted under hydrothermal conditions: a pressure of 5.8 MPa and a temperature of 200 degrees C for 2, 4, 6, 8, 10, and 20 h of reaction times. The samples obtained were characterized by means of scanning electron microscopy, X-ray diffraction, infrared spectroscopy, and transmission electron microscopy. Two defined populations of HAp fibers were found: A bundle of fibers 75 mum in length and 1-13 mum in diameter, and a second bundle of fibers 5 mum in length and less than 0.5 mum in diameter. Furthermore, an increase in HAp formation and a Ca/P ratio as a function of reaction time were observed. The growth mechanism of HAp is also discussed.
authors.affiliation: Centro Universitario de Vinculación, Benemérita Universidad Autónoma de Puebla, 29 Oriente 601-1 Col. Ladrillera de Benítez, C.P. Puebla 72520, México. lugo.ventura@cuv.buap.mx
authors.forename: V
authors.initials: V
authors.lastname: Rodríguez-Lugo
authors.forename: J Sanchez
authors.initials: JS
authors.lastname: Hernández
authors.forename: Ma J
authors.initials: MJ
authors.lastname: Arellano-Jimenez
authors.forename: P H
authors.initials: PH
authors.lastname: Hernández-Tejeda
authors.forename: S
authors.initials: S
authors.lastname: Recillas-Gispert
mesh_terms: D000818:Animals; D002119:Calcium Carbonate / Q000032:analysis; D017886:Durapatite / Q000737:chemistry*; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013215:Starfish / Q000648:ultrastructure*; D014961:X-Ray Diffraction
chemical_list: D017886:Durapatite; D002119:Calcium Carbonate