Samples will be treated with preparation for cryogenic or regular imaging. For that, samples are placed on a specially treated EM grid consisting of tiny holes in a film supported by a metal frame or on top of the carbon support. In regular transmission electron microscopy, the sample is placed on top of the prepared grid and, after blotting and drying, it is covered with a metal film to provide contrast during the imaging process.
For cryogenic sample preparation, the grid is then plunged into liquid ethane to flash-freeze it, resulting in the protein samples being embedded in a thin layer of vitreous ice. Once the frozen-hydrated grid is prepared, it is placed in the electron microscope and kept under cryogenic conditions throughout the experiment.