The Interdepartmental Equipment Facility
Cryostat - Leica
The Leica cryostat is essentially a microtome placed inside an upright freezer which facilitates preparation of frozen sections for microscopy. To minimize unnecessary warming of the sample, all necessary mechanical movements of the microtome can be controlled by hand using a wheel mounted outside the chamber.
The temperature can be varied, depending on the tissue being cut, down to -40oC. The precision of the cutting is in microns, with typical tissue sections in between 1 and 30 microns in width. Specimens that are soft at room temperature are mounted on a cutting medium, using a metal "chuck", and frozen to ~ -20oC. Once frozen, the specimen on the chuck is mounted in the microtome and sections are prepared.
The thin sections are next mounted on glass slides at room temperature where they quickly melt and adhere. The glass slide with the specimen is now dried and stained.