Cryo-electron microscopy of viruses.

Dubochet and colleagues introduced "Dubochet's vitrification method" to vitrify water by cooling it so rapidly that it solidified to form a glass instead of crystals. Using this method, the authors published the first images of a number of different viruses, round and hexagonal.

In 2017 Dubochet shared the Nobel Prize in Chemistry with Joachim Frank and Richard Henderson "for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution."

(Thanks to Juan Weiss for this reference and its interpretation.)