DND-167 (known as LysoSensor™ Blue DND-167, LysoView Blue) is a cell-permeable dye that selectively accumulates in acidic vesicles after being protonated. The dye has increased quantum yield in acidic environments allowing visualization of the lysosomes and late endosomes in living cells.
DND-167 is widely used as a pH indicator with pKa ~5.1. It has weak fluorescence at neutral pH but become much brighter at the blue region of spectra at acidic pH. An excitation/emission maxima of the dye at pH 3.0 are 370 and 425 nm, respectively.
The dye is supplied as a 1 mM solution in DMSO.