A novel pH “off–on” fluorescent probe for lysosome imaging

In the present paper, a new pH sensitive fluorescent probe based on a 4-acylated naphthalimide fluorophore was well designed and synthesized. It has a high specificity for lysosomes over other cell organelles. The intrinsic high signal to noise ratio in cell imaging, broad Stokes shift and practical fluorescence quantum yield of this probe will ensure its prominent position in the intracellular lysosome targeting and imaging toolbox.