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Updated: May 18, 2026
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Scanning Transmission Electron Microscopy Tomography in Virology: 3D Imaging of High-pressure Frozen, Freeze-substituted Samples
Published on: August 6, 2025
Electron tomography of HEK293T cells using scanning electron microscope-based scanning transmission electron
Yun-Wen You1, Hsun-Yun Chang, Hua-Yang Liao
1Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan.
Summary
Low-kV scanning transmission electron microscopy (STEM) offers enhanced contrast and reduced radiation damage for imaging light elements. This technique enables 3D reconstruction of cellular structures and nanoparticle uptake.
Area of Science:
- Electron microscopy
- Materials science
- Cell biology
Background:
- Standard transmission electron microscopy (TEM) can struggle with contrast for light elements and cause significant radiation damage.
- Three-dimensional (3D) imaging of biological specimens is crucial for understanding cellular structures and processes.
Purpose of the Study:
- To present low-voltage scanning transmission electron microscopy (STEM) coupled with electron tomography for 3D structural analysis.
- To demonstrate the capability of this technique for imaging light elements and assessing cellular uptake of nanoparticles.
Main Methods:
- Utilized a low-kV STEM setup (30 kV) with a custom specimen holder and multi-angle detector.
- Acquired 2D STEM projection images of a 1-μm-thick cell section over a ±50° tilt range.
- Reconstructed 3D volume structure using iterative algorithms (TomoJ plugin, ImageJ) and visualized cross-sections (Volume Viewer plugin, ImageJ).
Main Results:
- Achieved higher contrast for light elements due to stronger electron-atom scattering at low voltages.
- Minimized radiation damage, preserving specimen integrity.
- Successfully reconstructed 3D cellular structures and visualized the uptake and intracellular localization of gold nanoparticles.
Conclusions:
- Low-kV STEM-electron tomography provides a valuable method for high-contrast 3D imaging of light elements in biological samples.
- The technique offers sufficient resolution for studying cellular uptake mechanisms and nanoparticle localization, despite limited tilting angles.
- Public domain software (ImageJ plugins) facilitates accessible 3D reconstruction and analysis.
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