A method of preparing material for electron microscopy that allows the visualization of the interior of plasma membranes and organelles, and tight junctions between cells. Cells are frozen at −196°C and cracked so that the plane of fracture runs through the middle of lipid bilayers, separating the two halves. The exposed surfaces are then coated with carbon and platinum and the organic material is digested with enzymes (freeze etching), leaving a carbon-platinum replica of the fractured surface, which can be examined using the microscope.