September 4th – 2023: PhyLife talk by Line Lauritsen

The next PhyLife talk is by Line Lauritsen on 4^th September at 11:00 am in Lykeion. 

 Title: Ratiometric STED nanoscopy and lifetime imaging of novel Nile Red analogs for analysis of membrane packing in living cells

 Abstract: Subcellular membranes have specific lipid and protein compositions, which give rise to organelle-specific membrane packing and polarity. Due to its exquisite solvent sensitivity, the lipophilic fluorescence dye Nile Red has been used extensively to study membrane packing and polarity. Additionally, Nile Red derivatives are essentially non-fluorescent in water, allowing for their use in super-resolution microscopy experiments. Here, we compare the potential of derivatives of Nile Red with functional substituents for spectral stimulated emission depletion (STED) microscopy of membrane packing in living cells. All studied Nile Red derivatives reveal lower membrane packing in fibroblasts from healthy subjects compared to those from patients suffering from Niemann Pick type C (NPC) disease, a lysosomal storage disorder with the accumulation of cholesterol and sphingolipids in late endosomes and lysosomes (LE/LYSs). We find that a Nile Red derivative with a 10-fluoro atom has particularly high environmental sensitivity despite reduced molecular brightness. All Nile Red derivatives are suitable as an exchangeable dye for super-resolved spectral imaging of membrane packing in living cells.