X-ray absorption spectroscopy and high-energy XRD study of the local environment of copper in antibacterial copper-releasing degradable phosphate glasses

Pickup, David M. and Ahmed, Ifty and FitzGerald, Victoria and Moss, Rob M. and Wetherall, Karen and Knowles, Jonathan C. and Smith, Mark E. and Newport, Robert J. (2006) X-ray absorption spectroscopy and high-energy XRD study of the local environment of copper in antibacterial copper-releasing degradable phosphate glasses. Journal of Non-Crystalline Solids, 352 (28-29). pp. 3080-3087. ISSN 0022-3093. (Access to this publication is restricted)

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Abstract

Phosphate-based glasses of the general formula Na2O-CaO-P2O5 are degradable in an aqueous environment, and therefore can act as antibacterial materials through the inclusion of ions such as copper. In this study, CuO and Cu2O were added to Na2O-CaO-P2O5 glasses (1-20 mol% Cu) and X-ray absorption spectroscopy (XAS) and high-energy X-ray diffraction (HEXRD) used to probe the local environment of the copper ions. Copper K-edge X-ray absorption near-edge structure (XANES) spectra confirm the oxidation state of copper to be predominantly 2+ in all samples regardless of which copper oxide was used in the preparation. The XANES results suggest the structural environment of copper to be octahedral with respect to oxygen in all samples. The HEXRD results yield a Cu-O nearest-neighbour distance of 1.98 angstrom and associated coordination number of approximately six, both consistent with octahedral coordination. Analysis of the extended X-ray absorption fine structure (EXAFS) data also yields structural parameters consistent with copper in an octahedral environment. The HEXRD and EXAFS results reveal a Cu-P distance of 3.13 angstrom, which confirms that the copper ions are coordinated within the phosphate glass network and not phase-separated in domains of copper oxide. (c) 2006 Elsevier B.V. All rights reserved.

Item Type: Article
Uncontrolled keywords: biomaterials; X-ray diffraction; phosphates; X-ray absorption STREPTOCOCCUS-SANGUIS; NEUTRON-DIFFRACTION; TI COORDINATION; IN-VITRO; BIOFILMS; SYSTEM; XANES; FIBERS; OXYGEN; STATE
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Depositing User: Bob Newport
Date Deposited: 16 Jul 2008 18:28
Last Modified: 03 Jun 2014 15:10
Resource URI: http://kar.kent.ac.uk/id/eprint/8231 (The current URI for this page, for reference purposes)
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