CFSE is a cell-permeable green fluorescent dye (excitation and emission maxima are 494 and 520 nm, respectively). Once inside the cell, CFSE covalently couples to intracellular molecules via its succinimidyl group. As a result, it is retained within cells for a very long time. CFSE can be used to analyze cell proliferation by dye dilution resulting during cell division. It is also used to label cells and track their migration in vivo. CFSE lacks the diacetate groups of CFDA-SE and, as a result, is less cell permeable.
