CFSE (CFDA-SE) is a fluorescent dye with cell membrane permeability. CFSE irreversibly binds to intracellular proteins in living cells and is used for the detection of cell proliferation. The labeled cells fluoresce in green color with excitation wavelength of 488 nm and emission wavelength of 518 nm.

5(6)-CFDA (5-(6)-Carboxyfluorescein diacetate) is a cell-permeant esterase substrate that can serve as a viability probe that measures both enzymatic activities, which is required to activate its fluorescence, and cell-membrane integrity, which is required for intracellular retention of their fluorescent product.