Researchers developed a microscopy technique that measures the location and orientation of single molecules and used it to study the structural details of amyloid protein aggregates. (a) Single-molecule localization microscopy image of a network of amyloid aggregates. (b) Image showing Nile red binding orientations to amyloid surfaces, color-coded according to the average orientation measured within each bin. (c-g) Individual orientation measurements localized along fibril backbones within the white boxes in (b). The lines are oriented and color-coded according to the direction of the estimated angle. Horizontal white scale bars are length markers, 1 micron in (a), (b) and 100 nm in (f), (g).