Frozen section
Freezing tissue

Author: Jessica Wallace (see Authors page)

Revised: 25 July 2017, last major update October 2011

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Freezing tissue

Table of Contents
Freezing methods | Procedure | Videos
Cite this page: Freezing tissue. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/frozensectionfreezingtissue.html. Accessed November 20th, 2017.
Freezing methods
  • Note: most are used in conjunction with heat sinks
  • Histobath: being phased out
  • Cryowells: useful in keeping all tissue on an even plane; also helpful in eliminating loss of smaller tissues that are frozen with larger ones, although recommended to not freeze different sizes together
  • Aerosol sprays: often canned CO2 (but may aerosolize infectious diseases)
  • Liquid nitrogen
  • Isopentane based workflow (Virchows Arch 2008;452:305)
Procedure
  • OCT (optimal cutting temperature) or similar embedding media like TBS or Cryogel should be placed on an appropriate sized chuck that has been precooled in a cryostat
  • The chuck should be clean
  • A toothbrush is useful to remove tissue and OCT
  • Dipping the chuck in methanol removes ice crystals
  • Place the chuck into a -20 to -15 degree (optimal) cryostat; note that the OCT media should not be frozen completely
  • It is better to have a semisolid consistency; this will alleviate tissue artifact
  • Tissue size should be no greater than 3mm - 5mm in greatest dimension (thinner specimens have shorter freezing time and minimal ice crystal artifact formation)
  • The smaller the tissue, the more even and thorough the freeze
  • Place the tissue on the semisolid chuck and add more media rapidly over the tissue, covering it entirely but avoiding overflow
  • Place chuck quickly back into the cryostat
  • Apply heat sink or CO2 aerosol (optional) to rapidly freeze or use "quick freeze" option on cryostat
Videos


Embedding small specimens


Speed embedding