Cryo-electron microscopy

Cryogenic electron microscopy (cryo-EM) is a transmission electron microscopy technique applied to samples cooled to cryogenic temperatures. Developed in the 1970s, advances in detector technology and software allow biomolecular structures to be imaged at near-atomic resolution. The approach has become a popular alternative to X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy in structural biology. When scanning a biological specimen, the sample structure is preserved by embedding the specimen in vitreous ice. An aqueous sample solution is applied to a grid mesh and plunge-frozen in either liquid ethane or a mixture of liquid ethane and propane. The 2017 Nobel Prize in Chemistry was awarded to Jacques Dubochet, Joachim Frank, and Richard Henderson "for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution." Nature Methods also named cryo-EM as the "Method of the Year" in 2015.