Electron microscopic specimen preparation from low concentration of cell suspension using cytospin technique

Electron microscopic examinations are sometimes limited due to the small number of cells available for analysis. The purpose of this study was to determine the limit of cell concentration for a successful transmission electron microscopic preparation. Various concentrations of monocyte cell suspension were fixed in glutaraldehyde and osmium tetroxide according to the standard methods. Cell preparations were made on silane-coated glass slides in a cytospin centrifuge. The attached cells to the glass slides were dehydrated, and embedded in epoxy resin by routine electron microscopic technique. By this method, cell suspensions containing as low as 2x10(3) cells could show approximately 5 to 10 cells in each hole of the 150-mesh grids which was designated as the lowest limit for the successful preparation with detectable cells for evaluation. The fine structure of cells was clearly evident and the preparations were uniformly free from artifacts, similar or superior to those of cell pellet preparations. This method is useful whenever dealing with the samples containing a low number of cells, particularly those of clinical samples.