Naydenova, K. et al. Proc. Natl Acad. Sci. USA 116, 11718–11724 (2019).

Solutions of proteins and biomolecular complexes to be studied by single-particle cryo-electron microscopy (cryo-EM) are applied to a metal grid that is then rapidly frozen. Such metal grids are typically coated with a thin carbon film to encourage proteins to stick, but standard grids are subject to contamination and movement during imaging, which can compromise data quality. Naydenova et al. now report a method to coat gold grids with a monolayer film of graphene. This choice of cryo-EM support has near-ideal properties: gold grids are very stable, showing little movement during imaging in an electron beam. The graphene monolayer provides a conductive material that is invisible in the resolution range for cryo-EM and also provides a functionalizable surface to optimize the protein-orientation distribution. Using 30S ribosomal subunit and apoferritin test samples, the researchers demonstrate that the graphene-on-gold grids are compatible with high-resolution cryo-EM structure determination.