Super-Photostable Organic Dye for Long-Term Live-cell Single Protein Imaging

We introduce a super-photostable and bright organic dye, ‘Phoenix Fluor 555 (PF555)’, which exhibits an order-of-magnitude longer photobleaching lifetime than conventional organic dyes without the requirement of any anti-photobleaching additives. PF555 is an asymmetric cyanine structure where one side of indole from the conventional Cy3 is substituted with 3-oxo-quinoline. PF555 provides a powerful tool for long-term live-cell single-molecule imaging, as we demonstrated the dynamic interactions of the single-molecule epidermal growth factor receptor with clathrin-coated structures on the plasma membrane of a live cell under a physiological condition.