10% Neutral Buffered Formalin
- Routine fixative (Supplied free in our facility!)
- Don’t use 10% formalin—this will destroy your data
- Done at room temperature
- Adequate for many antibodies (know before you fix!)
- Not adequate for most lymphocyte markers
- Fix no longer than 16-24 hours (for most samples—excluding bone), transfer to 70% EtOH for samples for IHC
- Best to embed as soon as possible, but can stay in EtOH l
4% Paraformaldehyde (a buffered solution!)
- Commonly used in perfusion protocols
- Good for in situ hybridization (formalin works well, too)
- More gentle and considered slightly better than formalin for IHC, FISH
- Must be made just prior to use
- Keep it a 4C
Zinc Formalin (a buffered solution!)
- Commonly used for IHC when frozen not a good option
- More gentle and considered slightly better than 10% neutral buffered formalin for IHC
- Fix at room temperature
Bouin’s Solution (yellow)
- Contains picric acid l
- Maintains good morphology (good for brain)
- Decalcifies bone while fixing tissue
- May result in slight hardening of tissue if over-exposed (get into 70% EtOH within 48 hours)
- Colors tissue and affects some histochemical stains
Frozen tissues
- Freeze fresh or fixed tissues
- Good for immunohistochemistry for problem antibodies
- Decreased quality of morphology, better if pre-fixed
- Not good for bone (can’t cut the tissue)
- Store at -80