Separation of epoxy-embedded cell cultures from plastic flasks for electron microscopy.

Monolayers of cells grown in ordinary plastic flasks are fixed and embedded "in situ" into Epon. When polymerized at 40 C for 4 days instead of the usual 60 C, the Epon sheet containing the cells is easily detached from the bottom of the plastic container. The Epon sheet is observed by light microscopy as a histological preparation. Ultrathin sectioning of preselected areas can then be carried out in a horizontal plane.