Phase-contrast scanning transmission electron microscopy

Minoda, Hiroki; Tamai, Takayuki; Iijima, Hirofumi; Hosokawa, Fumio; Kondo, Yukihito

doi:10.1093/jmicro/dfv011

Cited by 17 publications

(10 citation statements)

References 13 publications

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“…This achieves super-resolution three-dimensional reconstruction without electron staining in FIB/ SEM technology. Moreover, combining super-resolution CL imaging with recently developed phase contrast scanning transmission electron imaging using an environmental cell 20,21 opens up the possibility of simultaneous observation of light and electron images with extreme spatial resolution without chemical staining.…”

Section: Resultsmentioning

confidence: 99%

Cathodoluminescence of green fluorescent protein exhibits the redshifted spectrum and the robustness

Akiba

Tamehiro

Matsui

et al. 2020

Sci Rep

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Green fluorescent protein (GFP) and its variants are an essential tool for visualizing functional units in biomaterials. This is achieved by the fascinating optical properties of them. Here, we report novel optical properties of enhanced GFP (EGFP), which is one of widely used engineered variants of the wild-type GFP. We study the electron-beam-induced luminescence, which is known as cathodoluminescence (CL), using the hybrid light and transmission electron microscope. Surprisingly, even from the same specimen, we observe a completely different dependences of the fluorescence and CL on the electron beam irradiation. Since light emission is normally independent of whether an electron is excited to the upper level by light or by electron beam, this difference is quite peculiar. We conclude that the electron beam irradiation causes the local generation of a new redshifted form of EGFP and CL is preferentially emitted from it. In addition, we also find that the redshifted form is rather robust to electron bombardment. These remarkable properties can be utilized for three-dimensional reconstruction without electron staining in focused ion beam/scanning electron microscopy technology and provide significant potential for simultaneously observing the functional information specified by super-resolution CL imaging and the structural information at the molecular level obtained by electron microscope.

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Section: Resultsmentioning

confidence: 99%

Cathodoluminescence of green fluorescent protein exhibits the redshifted spectrum and the robustness

Akiba

Tamehiro

Matsui

et al. 2020

Sci Rep

Self Cite

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“…Although ptychography 4D-STEM under zero defocus offers an phase image that can be combined with simultaneous Z-contrast imaging, its sine-shaped contrast transfer function at low spatial frequencies [26] remains to be improved. Recently, it has been shown that introducing a phase plate at the probe forming aperture of a STEM, which is equivalent to a Zernike phase plate in the back focal plane of a TEM [27] based on the principle of reciprocity [28], leads to a phase contrast transfer function (PCTF) that depends on the cosine of the aberration wave shift [29]. Another study demonstrated that the introduction of a patterned pre-specimen phase plate in the probe forming aperture combined with a virtual detector whose geometry matches that of the phase plate, a method called matched illumination detector interferometry (MIDI-STEM) [30], gives a linear phase image with enhanced contrast transfer of low spatial frequency specimen information.…”

Section: Introductionmentioning

confidence: 99%

Enhanced phase contrast transfer using ptychography combined with a pre-specimen phase plate in a scanning transmission electron microscope

et al. 2016

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The ability to image light elements in both crystalline and noncrystalline materials at near atomic resolution with an enhanced contrast is highly advantageous to understand the structure and properties of a wide range of beam sensitive materials including biological specimens and molecular hetero-structures. This requires the imaging system to have an efficient phase contrast transfer at both low and high spatial frequencies. In this work we introduce a new phase contrast imaging method in a scanning transmission electron microscope (STEM) using a pre-specimen phase plate in the probe forming aperture, combined with a fast pixelated detector to record diffraction patterns at every probe position, and phase reconstruction using ptychography. The phase plate significantly enhances the contrast transfer of low spatial frequency information, and ptychography maximizes the extraction of the phase information at all spatial frequencies. In addition, the STEM probe with the presence of the phase plate retains its atomic resolution, allowing simultaneous incoherent Z-contrast imaging to be obtained along with the ptychographic phase image. An experimental image of Au nanoparticles on a carbon support shows high contrast for both materials. Multislice image simulations of a DNA molecule shows the capability of imaging soft matter at low dose conditions, which implies potential applications of low dose imaging of a wide range of beam sensitive materials.

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“…That's because the sine type PCTF of the conventional STEM is almost zero at low spatial frequency and image contrast of such samples can't be obtained. Our previous STEM study shows the validity of the ZPP to visualize nm scale materials [1,2].…”

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confidence: 98%