CFSE

CFSE is a cell permeable, green fluorogenic tracer useful for multi-generational proliferation assays in flow cytometry platforms, with an excitation peak at 498 nm and an emission peak at 517 nm.

Principle and mechanism

CFSE (carboxyfluorescein diacetate succinimidyl ester) is a non-fluorescent dye that can be used to track cell proliferation over multiple generations. It is cell permeable, able to pass through the membrane of live cells. Once inside, the acetate groups of the molecule are cleaved by non-specific intracellular esterases, resulting in a fluorescent product that accumulates in the cell. Non-viable cells do not have active esterases, nor do their leaky membranes retain the dye; therefore they remain non-fluorescent. The activated CFSE stain forms covalent bonds with free primary amine groups exposed on surface and intracellular proteins, such as lysine side chains. This means CFSE labeling can be used for tracing, counting and identification of specific cells across multiple divisions.

Excitation and emission

CFSE (fluorescein, CFDA, SE) is a fluorescent compound with an excitation peak at 498 nm and an emission peak at 517 nm. It is well excited by the 488 nm argon laser line. The emission can be monitored with a flow cytometer using the FL1 channel or FITC filter set.