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Gram staining of kidney infected with Staphylococcus aureusTissue for paraffin embedding

For the best preservation of tissue morphology, the thickness of the tissue should be between 0.2 cm and 0.5 cm.

  • For further hematoxylin and eosin (H&E) staining, we recommend that you use a fresh solution of 10% neutral buffered formalin with a volume of at least 10 times that of the specimen.
  • For further immunoassaying, we recommend that you use 70% ethanol with a volume of at least 10 times that of the specimen.

Tissue for frozen section

There are two options for best results:

  • Do not fix tissue in a chemical fixative. Place tissue in a mould and surround by a cryoprotectant (e.g., optimal cutting temperature [OCT] before being snap frozen.)
  • Fix in 4% paraformaldehyde in 1XPBS (1 hour-overnight depending on specimen). Wash 3 x 10 minutes in 1X PBS and then immerse in 20% sucrose/1XPBS overnight at 4°C (or until specimen sinks to the bottom of the tube). Then embed in OCT on dry ice.

For help with freezing technique, contact Petia Stefanova at 416-480-6100, ext. 3356 or pstefanova@sri.utoronto.ca.

Tissue should be frozen (or fixed) as soon as possible to prevent the damaging effects of autolysis.


Petia Stefanova

416-480-6100, ext. 3356

Sunnybrook Health Sciences Centre
2075 Bayview Avenue, S4 408
Toronto, ON Canada M4N 3M5