Freezing Tissue Protocol

Materials

• Aluminum foil
• Plastic vial (about two-inches tall and one-inch wide)
• Dram bottle
• Wide-mouthed Thermoflask
• Applicator sticks (wooden)
• OCT (Optimum Cutting Temperature compound)
• Long forceps to hold the foil pocket and plastic vial
• Liquid nitrogen
• Isopentane
• Razor blade
• Dental wax
• Permanent marker pen (to label the foil pocket)
• DERC Lab Service Request Form

Method

1. Use the dram bottle as a mold to make a foil pocket. Make sure that the pocket is labeled.
2. Put a thin layer of OCT at the bottom of the foil pocket.
3. Quickly place tissue in the OCT, tapping quickly with applicator if necessary to center and orient the specimen.
4. Cover with OCT (about ½ inch).
5. Place the foil pocket in the vial containing isopentane. The foil pocket should not float, but the isopentane should reach a level higher than the level of OCT.
6. Set the vial with the aluminum pocket in liquid nitrogen. Do NOT let the liquid nitrogen spatter into the vial.
7. The OCT will freeze from outside in. The tissue is completely frozen when a small peak forms in center of the OCT.
8. Put the frozen block in a -20° C or -70° C freezer.  If the specimen needs to be transferred, put it in dry ice.

Do not allow specimen to thaw.