Investigating parasites in three dimensions: trends in volume microscopy

Cooper, Crystal; Thompson, R.C.A.; Clode, Peta L.

doi:10.1016/j.pt.2023.05.004

Cited by 4 publications

(4 citation statements)

References 103 publications

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“…To visualize large/thick biological samples (e.g., cells and tissues), various volume electron microscopy (EM) techniques have been developed [1,2]. In Array Tomography, sections prepared by microtome, cryo-microtome, or ultramicrotome are imaged using scanning electron microscopes (SEMs) or TEMs with a resolution larger than 60 nm (i.e., the section thickness).…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of Electron Interactions in an MeV-STEM for Thick Frozen Biological Sample Imaging

Wang,

Yang

2024

Applied Sciences

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A variety of volume electron microscopy techniques have been developed to visualize thick biological samples. However, the resolution is limited by the sliced section thickness (>30–60 nm). To preserve biological samples in a hydrated state, cryo-focused ion beam scanning electron microscopy has been developed, providing nm resolutions. However, this method is time-consuming, requiring 15–20 h to image a 10 μm thick sample with an 8 nm slice thickness. There is a pressing need for a method that allows the rapid and efficient study of thick biological samples while maintaining nanoscale resolution. The remarkable ability of mega-electron-volt (MeV) electrons to penetrate thick biological samples, even exceeding 10 μm in thickness, while maintaining nanoscale resolution, positions MeV-STEM as a suitable microscopy tool for such applications. Our research delves into understanding the interactions between MeV electrons and frozen biological specimens through Monte Carlo simulations. Single elastic scattering, plural elastic scattering, single inelastic scattering, and plural inelastic scattering events have been simulated. The electron trajectories, the beam profile, and the intensity change of electrons in each category have been investigated. Additionally, the effects of the detector collection angle and the focal position of the electron beam were investigated. As electrons penetrated deeper into the specimen, single and plural elastic scattered electrons diminished, and plural inelastic scattered electrons became dominant, and the beam profile became wider. Even after 10 μm of the specimen, 42% of the MeV electrons were collected within 10 mrad. This confirms that MeV-STEM can be employed to study thick biological samples.

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Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of Electron Interactions in an MeV-STEM for Thick Frozen Biological Sample Imaging

Wang,

Yang

2024

Applied Sciences

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“…The demagnifications of the condenser lens for the SRF and the DC cases are 8.75 and 33.5, respectively. The "Total w/o emittance" is the resolution defined in Equation (12). The "Total with emittance" is the resolution defined in Equation (11).…”

Section: Beamline Optics: Stem Columnmentioning

confidence: 99%

“…Due to the low electron dose required by biological samples to reduce the radiation damage and the short electron elastic mean free path at 100-300 keV, cryo-ET limits the sample thickness to 300-500 nm [8][9][10][11]. To visualize large/thick frozen biological samples (e.g., cells and tissues), various volume electron microscopy (EM) techniques have been developed [12,13]. In array tomography, sections prepared by microtome, cryo-microtome, or ultramicrotome are imaged using scanning electron microscopes (SEMs) or TEMs.…”

Section: Introductionmentioning

confidence: 99%

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Towards Construction of a Novel Nanometer-Resolution MeV-STEM for Imaging Thick Frozen Biological Samples

Yang,

Wang,

Maxson

et al. 2024

Photonics

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Driven by life-science applications, a mega-electron-volt Scanning Transmission Electron Microscope (MeV-STEM) has been proposed here to image thick frozen biological samples as a conventional Transmission Electron Microscope (TEM) may not be suitable to image samples thicker than 300–500 nm and various volume electron microscopy (EM) techniques either suffering from low resolution, or low speed. The high penetration of inelastic scattering signals of MeV electrons could make the MeV-STEM an appropriate microscope for biological samples as thick as 10 μm or more with a nanoscale resolution, considering the effect of electron energy, beam broadening, and low-dose limit on resolution. The best resolution is inversely related to the sample thickness and changes from 6 nm to 24 nm when the sample thickness increases from 1 μm to 10 μm. To achieve such a resolution in STEM, the imaging electrons must be focused on the specimen with a nm size and an mrad semi-convergence angle. This requires an electron beam emittance of a few picometers, which is ~1000 times smaller than the presently achieved nm emittance, in conjunction with less than 10−4 energy spread and 1 nA current. We numerically simulated two different approaches that are potentially applicable to build a compact MeV-STEM instrument: (1) DC (Direct Current) gun, aperture, superconducting radio-frequency (SRF) cavities, and STEM column; (2) SRF gun, aperture, SRF cavities, and STEM column. Beam dynamic simulations show promising results, which meet the needs of an MeV-STEM, a few-picometer emittance, less than 10−4 energy spread, and 0.1–1 nA current from both options. Also, we designed a compact STEM column based on permanent quadrupole quintuplet, not only to demagnify the beam size from 1 μm at the source point to 2 nm at the specimen but also to provide the freedom of changing the magnifications at the specimen and a scanning system to raster the electron beam across the sample with a step size of 2 nm and the repetition rate of 1 MHz. This makes it possible to build a compact MeV-STEM and use it to study thick, large-volume samples in cell biology.

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The application and development of electron microscopy for three-dimensional reconstruction in life science: a review

Zhao,

Yu,

Shentu

et al. 2024

Cell Tissue Res

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Investigating parasites in three dimensions: trends in volume microscopy

Cited by 4 publications

References 103 publications

Monte Carlo Simulation of Electron Interactions in an MeV-STEM for Thick Frozen Biological Sample Imaging

Monte Carlo Simulation of Electron Interactions in an MeV-STEM for Thick Frozen Biological Sample Imaging

Towards Construction of a Novel Nanometer-Resolution MeV-STEM for Imaging Thick Frozen Biological Samples

The application and development of electron microscopy for three-dimensional reconstruction in life science: a review

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