Coating sections for electron microscopic autoradiography: a stripping technique using liquid emulsion

A coating technique for electron microscope autoradiography is described which combines the advantage of forming an emulsion film by a dipping method with the ease of coating sections already on grids. Sections are coated so that a formvar support film separates the section and the emulsion crystals. This intermediate layer of formvar ensures a random distribution of the emulsion crystals. Using light gold sections, Ilford L-4 emulsion and Microdol-X development, the resolution of this technique, as determined by the half distance method, was 150 nm. The additional layer of formvar slightly reduced the image quality with biological samples in the electron microscope. This technique has a minimal loss of resolution and image quality for moderate resolution electron microscope autoradiography.