Polarity-responsive probe distinguishing different apoptotic stages in three distinct sets of fluorescence signals

Fluorescent probes for discrimination of healthy, early apoptotic, and late apoptotic cells in three different sets of fluorescent signals are promising tools for fundamental studies in biology, pathology, and pharmaceutical science. However, such fluorescent probes are rarely reported. Herein, we have fabricated a polarity-responsive probe (AP-NAP) which distinguished healthy, early apoptotic, and late apoptotic cells in three different sets of fluorescence signals. Probe AP-NAP targeted lysosomes in living cells and localized in the high-polarity region of lysosomal membranes. In early apoptotic cells, AP-NAP still targeted lysosomes but distributed in modest-polarity region of lysosomal membrane. In late apoptotic cells, AP-NAP transferred from lysosomes to the lipid droplets with ultralow polarity. In this manner, the solvatochromic AP-NAP achieved the separate recognition of the three different apoptotic stages. The probe AP-NAP was applied to successfully reveal the apoptotic stages induced by UV irradiation, biothiols scavenger, and anti-tumor drug.