title: Real time, in situ observation of the photocatalytic inactivation of Saccharomyces cerevisiae cells.
abstract: An in situ microscopy technique was developed to observe in real time the photocatalytic inactivation process of Saccharomyces cerevisiae (S. cerevisiae) cells by palladium-modified nitrogen-doped titanium oxide (TiON/PdO) under visible light illumination. The technique was based on building a photocatalytic micro-reactor on the sample stage of a fluorescence/phase contrast microscopy capable of simultaneously providing the optical excitation to activate the photocatalyst in the micro-reactor and the illumination to acquire phase contrast images of the cells undergoing the photocatalytic inactivation process. Using TiON/PdO as an example, the technique revealed for the first time the vacuolar activities inside S. cerevisiae cells subjected to a visible light photocatalytic inactivation. The vacuoles responded to the photocatalytic attack by the first expansion of the vacuolar volume and then contraction, before the vacuole disappeared and the cell structure collapsed. Consistent with the aggregate behavior observed from the cell culture experiments, the transition in the vacuolar volume provided clear evidence that photocatalytic disinfection of S. cerevisiae cells started with an initiation period in which cells struggled to offset the photocatalytic damage and moved rapidly after the photocatalytic damage overwhelmed the defense mechanisms of the cells against oxidative attack.
authors: School of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China; Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
authors: Jingtao
authors: J
authors: Zhang
authors: Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
authors: Xiaoxin
authors: X
authors: Wang
authors: Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China. Electronic address: qili@imr.ac.cn.
authors: Qi
authors: Q
authors: Li
authors: Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors: Jian Ku
authors: JK
authors: Shang
mesh_terms: D002384:Catalysis; D008854:Microscopy, Electron; D010777:Photochemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
keywords: Fluorescence staining; Phase contrast microscopy; Photocatalytic inactivation; Real time analysis, in situ observation; Saccharomyces cerevisiae cells; TiON/PdO