Supplementary Figure 4: Protein staining with CFSE fluorescent dye is similar in formalin alone or formalin–EDC fixed human embryonic kidney (HEK293) cells.
From: Non-reversible tissue fixation retains extracellular vesicles for in situ imaging
a, Low-power wide-field fluorescent photomicrographs of cultured HEK293 cells crosslinked with formalin–EDC and stained with CFSE (a, top panel, green) shows positive signal in cells. The nuclei were labeled (a, middle panel, Hoechst, blue) and co-localized signals (a, lower panel) show that CSFE and Hoechst stain formalin–EDC fixed cells’ protein. b, Representative photomicrographs of HEK293 cultured cells fixed with 4% formalin, stained with CSFE and Hoechst, and imaged using the same wide-field microscopy settings as in Supplementary Fig. 3a. Formalin-fixed cells showed positive signal (b, top panel, CSFE, green) and Hoechst (b, middle panel, blue). Merged images show co-localization of both stains (b, lower panel). Scale bars are (a, b) 100 µm.
