Figure 1
From: Volumetric, Nanoscale Optical Imaging of Mouse and Human Kidney via Expansion Microscopy
ExM schematic and validation in mouse kidney. (a) Fixed tissue is immunostained, treated with methacrylic acid N-hydroxy succinimidyl ester (MA-NHS) to covalently link antibody labels and proteins to the hydrogel during gelation, homogenized by enzymatic digestion, and then expanded ~4× along all dimensions by incubation with deionized water. (b–c) 100 μm thick mouse kidney section immunostained for podocin and imaged before (b) and after (c) expansion using a 10 × 0.4 numerical aperture (NA) air objective lens. (d) Quantification of expansion-induced distortions for panels b and c showing root mean square (RMS) error as a function of distance. (e–f) Mouse kidney section immunostained for podocin and imaged before (e) and after (f) expansion using a 63 × 1.2 NA water immersion objective lens. (g) Quantification of expansion-induced distortions for panels e and f. (h,i) Zoomed-in views of boxed regions in (e,f), showing that the expanded specimen successfully reveals interdigitated podocyte foot processes. (j) Cross-sectional profile of boxed region in (i). All distances and scale bars are in pre-expansion units. Scale bars, 50 µm (b,c), 5 µm (e,f), 1 µm (h,i).
