The Huck Institutes of the Life Sciences

Vapor fixation

An example of how vapor fixation was used to fix fungal fruiting bodies for scanning electron microscopy
Trichoderma sp.

Trichoderma sp.

Attempts to fix Trichoderma and Agaricus bisporous by conventional methods involving immersion in the fixatives of gluteraldehyde and osmium tetroxide failed to produce acceptable preservation for imaging in the SEM. A literature search produced a technique using vapor fixation. The following protocol produced fruiting bodies of Trichoderma with minimal shrinkage. Although it is a lengthy procedure, there is much less technician time than conventional procedures.


  1. Vaporfix mats of compost with the mycelia and fungal pathogen with 1% osmium tetroxide in 0.1M sodium cacodylate buffer placed into beem capsule lids placed near the mats in a disposalble petri dish for 4 days.
  2. Remove the lids and air dry the sample in the fume hood for 4 days.
  3. Mount onto an aluminum stub with a double sticky tab and colloidal silver
  4. Sputter-coat 10 nm of gold/palladium (2 min at 10 mAmps)



Quattlebaum, E.C. and G.R. Garner (1980) A Technique for preparing Beauveria spp. for scanning electron microscopy.Can. J. Bot. 58:1700-1703