Cryostat Leica CM 1950

Location: 8149 MRB3

Blades are not provided by the VBI.
High Profile disposable blades may be purchased online.
Users must purchase their own glass anti roll plate from Leica.
Please leave the specimen discs in the cryostat once you are finished cutting.
Other Resource Users will need them too.

Leave the cabinet temperature at -20 degrees and the object head at -21 degrees when finished.
Clean the cabinet using ethanol.
Turn on the UV light if you are using Human or infectious tissue.

Set-up:

Make sure cryostat is on and set at -15 to -20 degrees C.
You can set the object temperature by pressing the “Key” button and then the “+” button for object temperature.
Place tissue to be sliced in chamber to bring it to temperature as well as brushes, forceps, slide cases, etc.
Specimen disks (chucks) should be left at room temperature until you are ready to mount your tissue. Also leave slides at room Temperature.
To mount your tissue, first place the specimen disk inside the chamber and apply a generous circle of O.C.T.
When medium begins to freeze (starts to turn white), place tissue specimen in medium and freeze completely.
You can add additional mounting medium around tissue for added security.
Once specimen is securely embedded in frozen medium, place the specimen disk in the specimen head.
To adjust the plane of your specimen, open the lever to orient the specimen into
a favorable position relative to the knife/blade and close the lever again.

Trimming:

Begin by putting the specimen head in “home” position (all the way back). Use the stage forward button to bring your specimen very close to the knife.
When you are ready to begin trimming your tissue, press the trim/section button; The trim function is on when the green light is lit.
Use the+ and – buttons to change your trimming thickness (5-150 um).
Use the hand wheel to trim your tissue until you near the place where you will begin to collect tissue sections.
As you are trimming, you may need to make further adjustments to the plane of your tissue.
When you are near the place you will collect tissue sections, TURN THE TRIM FUNCTION OFF by pressing the trim function button once.

Collecting Tissue Specimens:

Before collecting tissue sections, put the anti-roll plate in place and practice a few sections so that you can make the proper adjustments for smooth tissue sections.
If sections are curling, tum the knob of the anti-roll plate clockwise. If sections are shredding, turn the knob counter-clockwise. Usually, only minute adjustments to the anti-roll plate are necessary to make a difference in tissue section quality.
When you have made all of the necessary adjustments and are at the place where you wish to begin collecting tissue sections: slice a section, carefully lift the antiroll plate away, use a brush to position your section, and carefully collect the section on a room temperature slide. If you are refreezing your tissue sections, be sure to allow all sections to dry at room temperature before placing the slides in the cryostat chamber.

Clean-up:

When you are finished slicing, remove the remaining tissue specimen from the specimen head. If you are planning to discard the remainder of the specimen, put the specimen outside of the chamber until it begins to thaw, at which time you can easily remove it from the specimen disk.
Use the large brush to sweep most of the discarded tissue sections into the drop pan below the head and empty the pan (use biohazard waste),
Use 100% EtOH to wipe out the cryostat chamber. DO NOT use water, as it will cause the chamber to become frosty.
Before you leave be sure the hand wheel is locked, the light is turned off, the chamber is clean, and the surrounding area is clean.