Effect of polyelectrolytes with various properties on sample aggregation. (a, g) Control samples of human 80S ribosome (a) and hexamerin (g) vitrified on regular holey carbon grids. (b–f, h–l) Samples of human 80S ribosome (b–f) and hexamerin (h–l) vitrified on grids coated with various polyelectrolytes. (b–d, h–j) The negatively charged polyelectrolytes ssDNA (b, h), pGlu (c, i) and PSS (d, j). (e, k) PEG was tested as a polyelectrolyte with no overall charge. (f, l) pLys was tested as a positively charged polyelectrolyte. The white scale bars in the micrographs represent 30 nm.