Fig. 4.

Cryo-electron tomography on a FIB lamella of a HeLa cell. a 2D transmission electron microscopy montage of a HeLa cell FIB lamella. Left: lamella top with an organometallic Pt layer. Right: thicker bottom side of the lamella. b x,y slice from a tomographic volume acquired at the framed area in a, showing a variety of organelles and cytoskeletal structures within the cytoplasm. MT: microtubules, ER: endoplasmic reticulum, LD: lipid droplet, mito: mitochondrion. c Enlarged area within the mitochondrion (framed region in b rotated by 90^o). A row of ATP synthase complexes is visible along the cristae membranes in top view (top arrowhead) and in side view (bottom arrowhead). d Corresponding x,z slice of the tomographic volume in b. The lamella thickness is 170 nm with a 5 nm Pt surface coating sputtered after lamella preparation. An additional ~45 nm layer of water vapor condensed on the finished lamella over the course of an hour during preparation. Tilt-series was recorded with the Volta phase plate, a target defocus of 0 μm and an object pixel size of 0.421 nm. Reprinted from [7], Journal of Structural Biology, vol. 197, M. Schaffer et al., Optimized cryo-focused ion beam sample preparation aimed at in situ structural studies of membrane proteins, pp. 73-82, Copyright 2017, with permission from Elsevier