Cryo-electron microscopy: An electron microscopic technique that involves freezing the biological sample in order to view the sample with the least possible distortion and the fewest possible artifacts. Abbreviated as cryo-EM.
In cryo-EM, the freezing of the sample is done in ethane slush to produce vitreous, or non-crystalline, ice. The frozen sample grid is then kept at liquid nitrogen temperature in the electron microscope and digital micrographs are collected with a camera.
The advantages of cryo-EM over traditional EM techniques include the preservation of the sample in a near-native hydrated state without the distortions from stains or fixatives needed for traditional EM. With image processing and averaging of multiple images, cyro-EM provides high resolution information (below 10 anstroms).