BrUSLEE (Bright Ultimately Short Lifetime Enhanced Emitter) possesses short fluorescence lifetime (800 ps) and high brightness (78% of EGFP) [Mamontova et al., 2018]

Compared to other fluorescent proteins with the shortest fluorescence lifetimes reported to date mGarnet2 (760 ps) and TagRFP675 (900 ps), BrUSLEE has exceptional fluorescence brightness (QY = 0.3, EC = 86 000 M⁻¹cm⁻¹)

Because of this unique combination îf brightness, photostability and subnanosecond fluorescence lifetime, BrUSLEE is mainly intended for fluorescence lifetime imaging microscopy.

For multiparameter FLIM in green channel BrUSLEE can be used with fluorescent proteins with similar fluorescence spectra and different fluorescence lifetimes: BrUSLEE (800 ps), SLIM (1.3 ns), TagGFP2 (3.2 ns).