freeze-fracturing

freeze-fracturing /freeze-frac·tur·ing/ (-frak´cher-ing) a method of preparing cells for electron-microscopical examination: a tissue specimen is frozen at −150° C, inserted into a vacuum chamber, and fractured by a microtome; a platinum carbon replica of the exposed surfaces is made, freed of the underlying specimen, and then examined.

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freeze-fracturing [frēz´-frak″chur-ing]

a method of preparing cells for electron-microscopical examination: a tissue specimen is frozen at −150°C, inserted into a vacuum chamber, and fractured by a microtome; a platinum carbon replica of the exposed surfaces is made, freed of the underlying specimen, and then examined.

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freeze-fracturing

a method used to examine cell structure in electron microscopy in which the specimen is frozen in liquid N₂ (−196°C) in the presence of a cryoprotectant (antifreeze) to prevent distortion; the frozen block is then cracked such that the fracture line passes through the hydrophobic middle of the lipid bilayers, thereby exposing the interior of the cell membranes. The resulting structure is then shadowed with platinum, the organic matter is dissolved away, and the replica is floated off and viewed in the electron microscope. A closely related technique is freeze-etch electron microscopy.