Electron cryotomography (ECT)

This emerging technology allows scientists to view three-dimensional images of macromolecular complexes and small bacterial cells. Thin samples are plunged into liquid nitrogen, which locks their water in place and preserves the structures in a natural, hydrated state. The frozen specimens are placed on an electron microscope that rotates the specimen around a single axis while a camera takes snapshots, which are then reconstructed into a three-dimensional image. HHMI investigator Grant Jensen has used electron cryotomography to look at a nanomachine weapon system inside Vibrio cholerae bacteria cells.

This F30 electron microscope takes multiple photos of a specimen which can then be pieced together into a three-dimensional image.
Jensen Lab / California Institute of Technology, 2004.

This snapshot, from a series of closely spaced images obtained with electron cryotomography, reveals details of a molecular system in Vibrio cholare cells that functions like a spring-loaded, poison-tipped dagger, capable of killing nearby cells.
Basler, M., Pilhofer, M., Henderson, G., Jensen, G. J., and Mekalanos, J. (2012) Nature: doi:10.1038/nature10846