Structural Characteristics of Antibacterial Bioresorbable Phosphate Glass

Authors


  • The authors wish to thank the EPSRC (EP/P502543, EP/C000714, EP/C00633/1, GR/T21080/01) and STFC (CMPC06103) for funding, and the use of the EPSRC Chemical Database Service at the STFC Daresbury Laboratory. We are grateful for the insight and help provided by Prof. A. C. Hannon of ISIS, STFC Rutherford Appleton Laboratory.

Abstract

Neutron diffraction with isotopic substitution has been used to probe the local environment of silver in a melt-quench derived bioresorbable phosphate glass. Samples enriched with 107Ag and 109Ag were prepared and neutron diffraction data collected. A first-order difference was taken between the data sets to give detailed information about the silver environment in the glass matrix. The measured Ag-O correlation has three components in the first coordination shell at 2.28 Å, 2.51 Å, and 2.58 Å with coordination numbers of 2.1, 2.7, and 1.1, respectively, consistent with silver occupying a distorted octahedral environment. These results have been correlated with those from Ag K-edge X-ray absorption near-edge spectroscopy measurements. The results suggest that the addition of silver to the (CaO)0.3(Na2O)0.2(P2O5)0.5 system has a significant effect on the host phosphate network, with shorter and more branched chains replacing the long chains and rings normally associated with the metaphosphate composition.

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