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Structural studies of bioactivity in sol-gel-derived glasses by X-ray spectroscopy

Skipper, Laura J., Sowrey, Frank E., Pickup, David M., Fitzgerald, Victoria, Rashid, Rumana, Drake, Kieran O., Lin, Zhongjie, Saravanapavan, Priya, Hench, Larry L., Smith, Mark E., and others. (2004) Structural studies of bioactivity in sol-gel-derived glasses by X-ray spectroscopy. Journal of Biomedical Materials Research Part A, 70A (2). pp. 354-360. ISSN 0021-9304. (doi:10.1002/jbm.a.30093) (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided) (KAR id:8219)

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http://dx.doi.org/10.1002/jbm.a.30093

Abstract

Extended X-ray absorption fine structure Spectroscopy and X-ray absorption near edge structure, X-ray fluorescence spectroscopy, and X-ray powder diffraction have been used to study the local calcium environment in four sol-gel-derived bioactive calcium silicate glasses of the general formula (CaO)(x)(SiO2)(1-x). The formation of a hydroxyapatite layer on the composition with the highest bioactivity (x = 0.3) with time has been studied, in an in vitro environment, by immersion in simulated body fluid (SBF) at 37degreesC. The calcium oxygen environment in the four compositions has been shown to be six-coordinate in character. Both the extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure show a gradual increase in coordination number and Ca-0 bond distance with longer exposure to SBF. X-ray fluorescence show that calcium is quickly lost from the samples on exposure to SBF and the calcium concentration then recovers with time. There is clear evidence that the recovery of calcium content is due to the formation of a CaO-P2O5-rich layer. Annealing of samples at 650degreesC shows the presence of what, on the length scales probed by X-ray diffraction, appears to be noncrystalline calcium phosphate after 1 h of exposure to an SBF solution, which becomes more crystalline on longer exposure. (D 2004 Wiley Periodicals, Inc.

Item Type: Article
DOI/Identification number: 10.1002/jbm.a.30093
Uncontrolled keywords: bioactive glass; sol-gel; X ray; extended X-ray absorption
Subjects: Q Science
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: Robert Newport
Date Deposited: 12 Jul 2008 14:06 UTC
Last Modified: 16 Nov 2021 09:46 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/8219 (The current URI for this page, for reference purposes)
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