Focused-ion beam SEM
Biological samples such as cells are often too thick to be imaged directly in a TEM. A focussed ion beam (FIB) of gallium ions can be used to remove material from certain areas of frozen samples, leaving the areas of interest intact and largely undisturbed. In this process, called FIB milling, material can be removed step-by-step from a cell, until a thin lamella with a thickness of typically 150-250 nm remains. We prepare lamella in one of our dedicated systems called cryoFIB-SEM, the Zeiss Auriga or Thermo Scientific Aquilos. After successful lamella preparation, the grid containing the lamella can be transferred to one of our Titan Krios systems and imaged by cryo-electron tomography.