title: Accurate characterization of pure silicon-substituted hydroxyapatite powders synthesized by a new precipitation route.
abstract: This paper presents a new aqueous precipitation method to prepare silicon-substituted hydroxyapatites Ca10(PO4)6-y(SiO4)y(OH)2-y(VOH)y (SiHAs) and details the characterization of powders with varying Si content up to y=1.25molmolSiHA(-1). X-ray diffraction, transmission electron microscopy, solid-state nuclear magnetic resonance and Fourier transform infrared spectroscopy were used to accurately characterize samples calcined at 400°C for 2h and 1000°C for 15h. This method allows the synthesis of monophasic SiHAs with controlled stoichiometry. The theoretical maximum limit of incorporation of Si into the hexagonal apatitic structure is y<1.5. This limit depends on the OH content in the channel, which is a function of the Si content, temperature and atmosphere of calcination. These results, particularly those from infrared spectroscopy, raise serious reservations about the phase purity of previously prepared and biologically evaluated SiHA powders, pellets and scaffolds in the literature.
authors.affiliation: Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, CNRS:FRE3312, 158 Cours Fauriel, F-42023 Saint-Etienne Cedex 2, France. marchat@emse.fr
authors.forename: David
authors.initials: D
authors.lastname: Marchat
authors.forename: Maria
authors.initials: M
authors.lastname: Zymelka
authors.forename: Cristina
authors.initials: C
authors.lastname: Coelho
authors.forename: Laurent
authors.initials: L
authors.lastname: Gremillard
authors.forename: Lucile
authors.initials: L
authors.lastname: Joly-Pottuz
authors.forename: Florence
authors.initials: F
authors.lastname: Babonneau
authors.forename: Claude
authors.initials: C
authors.lastname: Esnouf
authors.forename: Jérôme
authors.initials: J
authors.lastname: Chevalier
authors.forename: Didier
authors.initials: D
authors.lastname: Bernache-Assollant
mesh_terms: D018786:Bone Substitutes / Q000032:analysis* / Q000138:chemical synthesis*; D004340:Drug Contamination / Q000517:prevention & control; D017886:Durapatite / Q000032:analysis* / Q000737:chemistry*; D005590:Fractional Precipitation / Q000379:methods*; D008422:Materials Testing / Q000379:methods; D011208:Powders; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012825:Silicon / Q000032:analysis* / Q000737:chemistry*
chemical_list: D018786:Bone Substitutes; D011208:Powders; D017886:Durapatite; D012825:Silicon