The control and prevention of biofilm-related infections is an important public healthcare issue. Given the increasing antibiotic resistance among bacteria and fungi that cause serious infections in humans, promotion of new strategies combating microorganisms has been essential. One attractive approach to inactivate microorganisms is the use of semiconductor photo-catalysis, which has become the subject of extensive research. In this study, the bactericidal properties of four photo-catalysts, TiO₂, TiO₂-S, TiO₂-Eu and TiO₂-Eu-S, were investigated against established 24, 48, 72 and 96 h biofilms of Enterococcus The exposure of biofilms to the catalysts induced the production of superoxide radical anions. The best photo-catalytic inactivation was achieved with the TiO₂-Eu-S and TiO₂-S nanopowders and 24 h biofilms. Transmission electron microscopy images showed significant changes in the structure of the biofilm cells following photo-inactivation. The results suggest that doping with europium and modifying the surface with sulphate groups enhanced the bactericidal activity of the TiO₂ nanoparticles against enterococcal biofilms.
Keywords: Enterococcus; biofilms; europium-doped titanium dioxide; photo-catalysis.
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