Tissue-Tel O.C.T. Compond O.C.T. stands for Optimum Cutting Temperature. This compound formula is made up of water soluble glycols and resins which provides a convenient specimen matrix for cryostat sectioning. The working temperatures are –10°C (14°F) and below. Tissue-Tek will not leave rsidue on your slides during the staining procedure. Excess residue would normally produce an undesirable background.
So right about now you’re probably asking yourself, what the heck is he talking about? Of course, you lab rats know exactly what this stuff is used for. Tissue-Tek has a consistency that is very similar to wax. It is used before performing cyro-sectioning and then after fixation. Aside for using in conjunction with slides and slide covers, it is also used with standard, biopsy and orientation cassettes.
In other words, you want to use the compound before you freeze the tissue specimen section samples. We’re assuming that samples will be placed in a Dewar with liquid nitrogen.
Please note, when using Tissue-Tek on glass slides, you probably want to cut away as much of the excess wax with a knife or scalpel. Extra care needs to be taken when placing the sample into a cryomold. A small amount of the compound should be used in the bottom of the mold. Use caution not to move the tissue when adding the O.C.T. and be sure to remove any bubbles that form near the tissue with a forceps as these will cause problems with sectioning (cracking and fragmentation)