Gogniat Gaëtan, Thyssen Melilotus, Denis Michel, Pulgarin Cesar, Dukan Sam
ENAC-Laboratory for Environmental Biotechnology, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
FEMS Microbiol Lett. 2006 May;258(1):18-24. doi: 10.1111/j.1574-6968.2006.00190.x.
The bactericidal effect of photocatalysis with TiO2 is well recognized, although its mode of action is still poorly characterized. It may involve oxidation, as illuminated TiO2 generates reactive oxygen species. Here we analyze the bactericidal effect of illuminated TiO2 in NaCl-KCl or sodium phosphate solutions. We found that adsorption of bacteria on the catalyst occurred immediately in NaCl-KCl solution, whereas it was delayed in the sodium phosphate solution. We also show that the rate of adsorption of cells onto TiO2 is positively correlated with its bactericidal effect. Importantly, adsorption was consistently associated with a reduction or loss of bacterial membrane integrity, as revealed by flow cytometry. Our work suggests that adsorption of cells onto aggregated TiO2, followed by loss of membrane integrity, is key to the bactericidal effect of photocatalysis.
尽管二氧化钛光催化的作用模式仍未得到充分表征，但其杀菌效果已得到广泛认可。由于光照下的二氧化钛会产生活性氧物种，所以其杀菌作用可能涉及氧化过程。在此，我们分析了光照下的二氧化钛在氯化钠 - 氯化钾或磷酸钠溶液中的杀菌效果。我们发现，细菌在氯化钠 - 氯化钾溶液中会立即吸附在催化剂上，而在磷酸钠溶液中吸附则会延迟。我们还表明，细胞在二氧化钛上的吸附速率与其杀菌效果呈正相关。重要的是，流式细胞术显示，吸附始终与细菌膜完整性的降低或丧失有关。我们的研究表明，细胞吸附到聚集的二氧化钛上，随后膜完整性丧失，是光催化杀菌效果的关键。
