LysoTracker Red (LysoTracker Red DND-99)

LysoTracker Red (LysoTracker Red DND-99) is an acidotropic, red-fluorescent probe (Ex/Em 577/590 nm) that selectively stains lysosomes and late endosomes in live cells. As a hydrophobic weak base, it freely diffuses across membranes at neutral pH (~7.4), becomes protonated in acidic compartments (pH 4.5-6.0), and traps via charge retention, preventing efflux for high-contrast imaging.