Specimen preparation method cryogenic methods

In this chapter, we summarize the basic principle of TEM and three types of the typical specimen preparation techniques negative staining, freeze-fracture, and cryogenic methods. Then, TEM tomography showing the... 

Freeze-Fracture Method A sample preparation technique used in electron microscopy in which specimens are quickly frozen in a cryogen and then cleaved to expose interior surfaces. In some techniques, the sample is then observed directly in an electron microscope equipped with a cryogenic stage in other cases, the cleaved sample is coated with a metal coating to produce a replica, which is observed in the electron microscope. See also Electron Microscopy. 

Cryogenic transmission microscopy (Cryo-TEM) is an excellent method, by using which the objects in solution can be visualized without fixing and staining. As mentioned above, negative staining is a convenient method for the preparation of TEM specimen however, the object can be visualized only in dry state, which is sometimes much different from the structme in solution. In addition, using Cryo-TEM the structmal information inside the object can be obtained in contrast to freeze-fracture replica method. 

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