Polarity sensitive probes for super resolution STED microscopy

The lateral organization of molecules in the cellular plasma membrane plays an important role in cellular signaling. A critical parameter for membrane molecular organization is how the membrane lipids are packed (or ordered). Polarity sensitive dyes are powerful tools to characterize such lipid membrane order, employing for example confocal and two-photon microscopy. The investigation of potential lipid nanodomains, however, requires the use of super resolution microscopy. Here, we test the performance of the polarity sensitive membrane dyes Di-4-ANEPPDHQ, Di-4-AN(F)EPPTEA and NR12S in super resolution STED microscopy. Measurements on cell-derived membrane vesicles, in the plasma membrane of live cells, and on single virus particles show the high potential of these dyes for probing nanoscale membrane heterogeneity.