Plastic embedding

Routine preparation of biological material for classical transmission electron microscopy (TEM) through fixation, embedding in epon and sectioning. The cells or tissue is fixed with glutaraldehyde and post-fixed with osmium tetroxide. Contrast is added in the form of heavy metals using Uranyl acetate and if necessary, also Tannic acid. Sample is dehydrated with graded series of ethanol and embedded in Epon. After polymerization the specimen is sectioned in an ultra-microtome to cut sections of varying thickness, suitable for the microscopy technique we want to use.   

In addition to embedding tissue pieces or pellets of cells it is also possible to embed cells as monolayers cultured on glass coverslips or MatTek dishes through the flat embedding technique. Cells are processed while remaining attached to the coverslip, which is removed only after polymerization to ensure well-preserved morphology and orientation.