JC-1 is a novel cationic carbocyanine dye that accumulates in mitochondria. As a mitochondrial dye, JC1 stains mitochondria in living cells in a membrane potential-dependent fashion. JC-1 iodide is membrane permeable and is often used for flow cytometry and fluorescent microscopy. Green fluorescent JC-1 existing as a monomer (λem=527nm) at low concentrations or at low membrane potential. However, at higher concentrations (aqueous solutions above 0.1µM) or higher potentials, JC-1 forms red fluorescent 'J-aggregates'.
