NBD-PE (N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-snglycero-3-phosphoethanolamine, triethylammonium salt) in combination with Rhodamine-DHPE (#60026) or Texas Red®-DHPE (#60027) has been used to study membrane fusion via fluorescence resonance energy transfer (FRET) (1-3). NBD-PE has also been used in photobleaching recovery measurement.