JC-1 (5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine chloride) is a mitochondrial dye that stains mitochondria in living cells in a membrane potential-dependent fashion.JC-1 monomer is in equilibrium with so-called J-aggregates, which are favored at higher dye concentration or higher mitochondrial membrane potential. The monomer JC-1 has green fluorescence (&lamba; Em = 527 nm),while the J-aggregates have red fluorescence (&lamba; Em = 590nm). Therefore, it is possible to use the fluorescence ratio technique to study mitochondrial membrane potentials. JC-1 is particularly useful for apoptosis studies. In apoptotic cells, the dye stays in the cytoplasm and fluoresces green. It has also been used in high throughput drug screening applications.    JC-1, iodide is the original salt form of the dye. Biotium developed JC-1 chloride salt for applications where iodide ion is not desired. JC-1 chloride may also have the advantage of being slightly more water soluble than the iodide salt.    ε (MeOH) = 190,000  Red solid soluble in DMSO  Store at 4°C and protect from light, especially in solution  C25H27Cl5N4  MW: 561.5