CFSE is widely used for cell tracking and cell proliferation studies. It can also be used for CTL assays and cell motility studies. CFSE readily crosses intact cell membranes. Once inside the cell, intracellular esterases cleave the acetate group, producing a fluorescent carboxyfluorescein molecule. Succinimidyl ester groups react with primary amines to cross-link the dye to intracellular proteins. Cell division can be determined by sequential halving of CFSE fluorescence intensity. CFSE-labeled cells are fixed and permeabilized for analysis of intracellular targets using standard formaldehyde-containing fixatives and saponin-based permeabilization buffers, such as the Foxp3 Transcription Factor Staining Buffer Kit (Cat. No. 00- 5523) or IC fixation buffer (Cat. No. 00-8222) and permeabilization buffer (10X) (Cat. No. 00-8333).

The molecular weight of CFSE is 557.47. After cleaving the acetate group, its excitation peak is 494 nm and emission peak is 521 nm. Each vial of CFSE can be reconstituted with 90µL of anhydrous DMSO to a stock solution with a concentration of 10 mM; after reconstitution, it should be used within 6 months and stored with a desiccant at -20°C in the dark; avoid freezing and thawing .

Reported Applications
Flow Cytometry Analysis, Microscopy