LR White sections as slot grid support films for transmission electron microscopy

The utility of LR White sections as slot grid support films for the examination of thin resin-embedded tissue sections by transmission electron microscopy was investigated and compared with traditional formvar-carbon films. Throughout a variety of staining procedures, which involved the use of organic solvent, oxidizing agents, strong acid and prolonged incubation, LR White support films remained intact and the attached tissue sections remained adherent. By contrast, complete loss of formvar-carbon support films occurred in 25% of preparations during routine staining with aqueous reagents. This loss increased to 62% following staining with either alcoholic or oxidizing and acidic stains, and to 66% following prolonged (immunohistochemical) staining. Tissue contrast, ultrastructural detail and immunohistochemical staining intensity were comparable between sections on the two types of support film. The use of LR White sections as support films for slot grids represents a quick, cheap, simple and robust alternative to traditional support films and, furthermore, requires no carbon coating.