title: Cathodoluminescence and Electron-Induced Fluorescence Enhancement of Enhanced Green Fluorescent Protein.
abstract: Becaues the spatial resolution of fluorescence microscopy is not high enough to study the molecular level of relationship between the structure and function of biological specimens, correlative light and electron microscopy has been used for this purpose. Another possibility for a high-resolution light microscopy is cathodoluminescence microscopy. Here, we report a new phenomenon, the electron-induced activation of luminescence (cathodoluminescence) and electron-enhanced fluorescence for the enhanced green fluorescent protein (EGFP). This was found using our recently developed hybrid fluorescence and electron microscopy. Contrary to the past reports, which showed a degradation of organic compounds by electron irradiation, stable cathodoluminescence emitted from an organic molecule, EGFP, has been observed using the hybrid microscopy. Addition of the glycerol promoted the fluorescence enhancement of EGFP probably due to the change in the electronic state density of excitation channels from the ground to the excited state or of relaxation channels from the excited to the emission state. Stable cathodoluminescence and enhanced fluorescence of the EGFP may introduce a cathodoluminescence microscopy, which will increase the variety of the imaging to investigate the biological compounds.
authors: National Institute for Physiological Sciences , 5-1 Higashiyama, Myodaiji, Okazaki, Japan.
authors: Kuniaki
authors: K
authors: Nagayama
authors: Tokyo University of Agriculture and Technology , 2-24-16 Naka-cho, Koganei, Tokyo, Japan.
authors: Tsubasa
authors: T
authors: Onuma
authors: Tokyo University of Agriculture and Technology , 2-24-16 Naka-cho, Koganei, Tokyo, Japan.
authors: Ryosuke
authors: R
authors: Ueno
authors: Tokyo University of Agriculture and Technology , 2-24-16 Naka-cho, Koganei, Tokyo, Japan.
authors: Katsuyuki
authors: K
authors: Tamehiro
authors: Tokyo University of Agriculture and Technology , 2-24-16 Naka-cho, Koganei, Tokyo, Japan.
authors: Hiroki
authors: H
authors: Minoda
mesh_terms: D004583:Electrons; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D006801:Humans; D049449:Luminescence; D008856:Microscopy, Fluorescence
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins