Photo-catalytic inactivation of an Enterococcus biofilm: the anti-microbial effect of sulphated and europium-doped titanium dioxide nanopowders

• Published in: FEMS microbiology letters Vol. 363; no. 7; p. fnw051
• Main Authors: Dworniczek, Ewa, Plesch, Gustav, Seniuk, Alicja, Adamski, Ryszard, Michal, Róbert, Čaplovičová, Mária
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.04.2016
• Subjects: Anions; Anti-Bacterial Agents - pharmacology; Antibiotic resistance; Antibiotics; Bactericidal activity; Biofilms; Biofilms - drug effects; Biofilms - growth & development; Catalysis; Catalysts; Deactivation; Enterococcus; Enterococcus - drug effects; Enterococcus - ultrastructure; Europium; Europium - chemistry; Europium - pharmacology; Fungi; Image transmission; Inactivation; Luminescent Agents - chemistry; Luminescent Agents - pharmacology; Microbial Viability; Microbiology; Microorganisms; Microscopy, Electron, Transmission; Nanoparticles; Nanoparticles - chemistry; Nanoparticles - ultrastructure; Photosensitizing Agents - pharmacology; Sulfates - chemistry; Superoxide; Superoxides - metabolism; Titanium - pharmacology; Titanium dioxide; Transmission electron microscopy; europium-doped titanium dioxide; photo-catalysis; biofilms; Enterococcus
• ISSN: 1574-6968; 0378-1097; 1574-6968
• DOI: 10.1093/femsle/fnw051

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. The Enterococcus biofilms are more susceptible to the photo-toxic effect of sulphated and europium-doped anatase than to pure titanium dioxide.