title: Rare-earth-doped nanophosphors for multicolor cathodoluminescence nanobioimaging using scanning transmission electron microscopy.
abstract: We describe rare-earth-doped nanophosphors (RE-NPs) for biological imaging using cathodoluminescence(CL) microscopy based on scanning transmission electron microscopy (STEM). We report the first demonstration of multicolor CL nanobioimaging using STEM with nanophosphors. The CL spectra of the synthesized nanophosphors (Y2O3∶Eu, Y2O3∶Tb) were sufficiently narrow to be distinguished. From CL images of RE-NPs on an elastic carbon-coated copper grid, the spatial resolution was beyond the diffraction limit of light.Y2O3∶Tb and Y2O3∶Eu RE-NPs showed a remarkable resistance against electron beam exposure even at high acceleration voltage (80 kV) and retained a CL intensity of more than 97% compared with the initial intensity for 1 min. In biological CL imaging with STEM, heavy-metal-stained cell sections containing the RE-NPs were prepared,and both the CL images of RE-NPs and cellular structures, such as mitochondria, were clearly observed from STEM images with high contrast. The cellular CL imaging using RE-NPs also had high spatial resolution even though heavy-metal-stained cells are normally regarded as highly scattering media. Moreover, since theRE-NPs exhibit photoluminescence (PL) excited by UV light, they are useful for multimodal correlative imaging using CL and PL.
authors.affiliation: Osaka University, Institute for NanoScience Design, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Furukawa
authors.affiliation: Osaka University, Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Fukushima
authors.affiliation: Osaka University, Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Niioka
authors.affiliation: Tokyo Institute of Technology, Department of Physics, Oh-okayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Osaka University, Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Miyake
authors.affiliation: Osaka University, Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Araki
authors.affiliation: Osaka University, Graduate School of Engineering Science, Department of Mechanical Science and Bioengineering, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Hashimoto
mesh_terms: D003116:Color; D003287:Contrast Media / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008163:Luminescent Measurements / Q000379:methods*; D008674:Metals, Rare Earth / Q000737:chemistry*; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods*; D053758:Nanoparticles / Q000648:ultrastructure*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013347:Subcellular Fractions / Q000648:ultrastructure*
chemical_list: D003287:Contrast Media; D008674:Metals, Rare Earth