title: Structural characterization by x-ray methods of novel antimicrobial gallium-doped phosphate-based glasses.
abstract: Antimicrobial gallium-doped phosphate-based glasses of general composition (P(2)O(5))(0.45)(CaO)(0.16)(Na(2)O)(0.39-x)(Ga(2)O(3))(x) (where x=0, 0.01, 0.03, and 0.05) have been studied using the advanced synchrotron-based techniques of Ga K-edge x-ray absorption spectroscopy and high-energy x-ray diffraction to provide a structural insight into their unique properties. The results show that the Ga(3+) ions are octahedrally coordinated. Furthermore, substitution of Na(2)O by Ga(2)O(3) strengthens the phosphate network structure because the presence of GaO(6) octahedra inhibits the migration of the remaining Na(+) ions. The results are discussed in terms of the use of Na(2)O-CaO-P(2)O(5) glasses as controlled-delivery devices for antimicrobial Ga(3+) ions in biomedical applications. We are thereby able to relate the atomic-scale environment of the Ga(3+) ions beneficially to the glass dissolution, and thus to their ability to disrupt bacterial cell activity by usurping the role of iron.
authors.affiliation: School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom. dmp@kent.ac.uk
authors.forename: D M
authors.initials: DM
authors.lastname: Pickup
authors.forename: R M
authors.initials: RM
authors.lastname: Moss
authors.forename: D
authors.initials: D
authors.lastname: Qiu
authors.forename: R J
authors.initials: RJ
authors.lastname: Newport
authors.forename: S P
authors.initials: SP
authors.lastname: Valappil
authors.forename: J C
authors.initials: JC
authors.lastname: Knowles
authors.forename: M E
authors.initials: ME
authors.lastname: Smith
mesh_terms: D000042:Absorption; D000890:Anti-Infective Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005708:Gallium / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D000890:Anti-Infective Agents; D010710:Phosphates; D005708:Gallium