Comparison of samples vitrified on regular holey carbon grids and ssDNA-coated grids. Samples of hexamerin (a–f), human 80S ribosome (g–i) and apoferritin (j–l) vitrified on regular holey carbon grids (a, g, j) and ssDNA-coated holey carbon grids (b, h, k). The samples on regular grids (a, g, j) are aggregated, whereas those on ssDNA-coated grids (b, h, k) are monodisperse. The white scale bars in the micrographs represent 30 nm. (c, d) 3D cryo-EM reconstructions of hexamerin calculated from images obtained from a regular holey carbon grid (c) with highlighted detail (red β-sheet) from the map (d). (e, f) 3D cryo-EM reconstructions of hexamerin obtained from an ssDNA-coated cryo-EM grid. (i, l) Cryo-EM reconstructions of apoferritin (i) and human 80S ribosome (l) obtained from samples vitrified on ssDNA-coated grids.