cryo-electron microscopy

"Cryo-electron microscopy" is a microscopy method used for the observation of biological specimens at the temperature of liquid nitrogen or liquid helium. The biological specimens of purified proteins, viruses, lipid molecules, etc. are prepared by various freezing methods (ice embedding, freeze sectioning, etc.) without staining, and are inserted into a microscope with the specimens kept frozen. Since biological specimens are mostly composed of light elements, scattering contrast is extremely weak to observe. Thus, the specimen is observed using phase contrast produced at a defocus of a few μm.
For inserting the low-temperature (frozen) specimens, two techniques are available: the use of a cryo-transfer holder or a dedicated cryo-electron microscope which has an automatic specimen transfer mechanism.
3D structure analysis methods using cryo-electron microscopy include single particle analysis and tomography.

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