



@article {2526,
	title = {Structural analysis of Si-substituted hydroxyapatite: Zeta potential and X-ray photoelectron spectroscopy},
	journal = {Journal of Materials Science: Materials in MedicineJ. Mater. Sci. Mater. Med.},
	volume = {13},
	year = {2002},
	note = {Cited By (since 1996): 59Export Date: 21 November 2012Source: ScopusCODEN: JSMMEdoi: 10.1023/A:1021177601899Language of Original Document: EnglishCorrespondence Address: Santos, J.D.; INEB - Inst. de Engenharia Biomedica, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal; email: jdsantos@fe.up.ptChemicals/CAS: calcium oxide, 1305-78-8; calcium phosphate, 10103-46-5, 13767-12-9, 14358-97-5, 7758-87-4; hydroxyapatite, 1306-06-5, 51198-94-8; phosphate, 14066-19-4, 14265-44-2; silicon, 7440-21-3Tradenames: Philips PW1606 spectrometer, Philips; Siemens D5000 X ray diffractometer, Siemens; Sotax CE6Manufacturers: Philips; SiemensReferences: Carlisle, E.M., (1984) Fed. Proc., 43, p. 680;Carlisle, E.M., (1986) Silicon Biochemistry, , edited by D. Evered and M. O{\textquoteright}Connor (Wiley, New York); 
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},
	month = {2002///},
	pages = {1123 - 1127},
	abstract = {The aim of this study was to determine the effect of the incorporation of silicon on the surface charge of hydroxyapatite (HA) and to assess surface structural changes of HA and Si-HA induced by dissolution in both static and dynamic systems. X-ray photoelectron spectroscopy (XPS) analysis showed that SiO                        4
                        4- groups were substituted for PO
                        4
                        3- groups in the silicon-hydroxyapatite (Si-HA) lattice according to a previously proposed substitution mechanism without the formation of other crystalline phases, such as tricalcium phosphate or calcium oxide. The substituted silicon induced a decrease in the net surface charge and the isoelectric point of HA as determined by zeta potential (ZP) measurements. At physiological pH = 7.4 the surface charge of Si-HA was significantly lowered compared to unmodified HA, i.e. -50 {\textpm}5 to - 71 {\textpm} 5 eV, caused by the presence of silicate groups in the HA lattice, which may account for a faster in vitro apatite formation using SBF testing. XPS results indicated that silicon seems to be preferentially leached out from Si-HA surface compared to other ionic species after dissolution studies in tris-buffer using a dynamic system. {\textcopyright} 2002 Kluwer Academic Publishers.
},
	keywords = {calcium oxide, calcium phosphate, Chemical modification, conference paper, crystal structure, Dissolution, Electric Potential, electricity, hydroxyapatite, in vitro study, isoelectric point, Lime, molecular dynamics, pH, pH measurement, phase transition, phosphate, Phosphorus Compounds, priority journal, reaction analysis, Silicon, Silicon compounds, silicon derivative, structure analysis, surface property, X ray photoelectron spectroscopy, Zeta potential},
	isbn = {09574530 (ISSN)},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0036983515\&partnerID=40\&md5=8bca315737eb24dc8e8f2e2be567c7fc},
	author = {Botelho, C.M. and Lopes, M.A. and Gibson, I.R. and Best, S.M. and Santos, J.D.}
}
