Home > Specimen Preparation > Basic SEM Protocol
Fixation and dehydration for the SEM are carried out similarly to those for the TEM (see TEM fixation protocol). Because most SEM involves examination of surface structures, fixation-penetration is generally less critical than for TEM and much larger samples may be processed. The times in primary fixative, buffers, and alcohol may be extended if the tissue pieces are large. After dehydration through an ascending series of ethanols ending in 100% ethanol, the SEM protocol requires drying without introducing surface tension artifacts. This can be done by using our Pelco critical point drier or by drying from the chemical HMDS, which is available from Ted Pella, Inc., as well as from many other electron microscopy suppliers.
After drying, the samples are carefully mounted on an aluminum stub using either silver paint or a double stick carbon tape. Samples are then introduced into the chamber of the sputter coater and coated with a very thin film of gold\palladium before SEM examination.
