Fig. 3

STED and CLSM images of Aβ amyloid aggregates in a brain tissue section from a 17 months old 3×TgAD mouse. A1/B1 STED (A1) and CLSM (B1) images of a small plaque. The yellow arrows point to a detail at the plaque outskirt. C1 Fluorescence intensity distribution profile shows that the detail from A1/B1 is a single fiber with an apparent diameter of 87 nm measured by STED (black squares and corresponding Gaussian fit (red line)) and 320 nm by Confocal (grey diamonds and corresponding Gaussian fit (blue line)). A2/B2 STED (A2) and CLSM (B2) images of a detail in the small plaque (magnified in A2’/B2’) showing bundled fibers that are clearly distinguishable by STED, but not by Confocal imaging. C2 Fluorescence intensity distribution profile shows that STED could distinguish two fibers, 80 and 110 nm in diameter, that are 260 nm apart (black squares and corresponding Gaussian fit (red line)), whereas confocal imaging showed a blurred rod-like structure with a broad, single-peak fluorescence intensity distribution profile (grey diamonds and corresponding Gaussian fit (blue line)). A3/B3 STED (A3) and CLSM (B3) images of a cell-dense area (DAPI nuclear stain (blue)), showing short fibrils in the perinuclear region and long fibrils located between cells that are hardly visible due to the large extracellular depositions of structured aggregates present nearby, where the 1C3-DyLight633 antibody binds in a large excess (red). Scale bar in all images is 2 μm