Negative Stain Transmission Electron Microscopy

This method is routinely used in screening experiments to assess sample quality. It is also used to answer specific questions concerning, e.g., protein-protein interactions and protein assembly; antibodies can be visualized when bound to their antigen.

The sample is embedded in a layer of a heavy metal salt. This scatters a large number of electrons and looks dark on the images.

The slider above shows a typical EM grid at increasing magnification. The red boxes indicate the regions enlarged in the next image. The EM-grid was first coated with a perforated carbon layer, and then with a thin carbon film to which the sample was later adsorbed and negatively stained.

The magnification series is continued in the slider below. The thin carbon spanning a hole in the perforated layer and the negatively stained protein complexes on it, become increasingly visible.

Images courtesy of Philippe Ringler, C-CINA.