CFDA-SE (5(6)-carboxyfluorescein diacetate succinimidyl ester) is a stable, cell-permeable diacetate precursor to CFSE. Upon diffusion into the cell, intracellular esterases cleave the acetate group to generate CFSE, which interacts with cellular amines via its succinimidyl groups to generate a highly fluorescent green dye that is impermeant to the cell membrane. CFDA-SE is frequently used in cell proliferation assays, as it is partitioned approximately equally between the progeny so that cell division can be followed as a successive halving of the fluorescence intensity through multiple generational divisions. CFDA-SE is also used for motility assays and in vivo cell tracking experiments. CFDA-SE-labeled cells can be detected with any instrument/filter set compatible with fluorescein detection.