JC-1 . iodide

JC-1 is a very sensitive fluorescent probe to test Pgp activity. In acute myeloid leukemia (AML) samples JC-1 is capable of distinguishing between resistant, intermediate and sensitive groups, whereas rhodamine 123 only recognizes the resistant group. As in cell lines, the red emission band (597nm) of JC-1 appears to be more convenient for detection of low-level resistance in AML than other probes, such as rhodamine 123 (529nm) or calcein-AM (517nm). Green fluorescent JC-1 existing as a monomer (λ_em=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’, which exhibit a broad excitation spectrum and a very narrow emission spectrum (λ_em=590nm). JC-1 stains mitochondria in living cells in a membrane potential-dependent function. JC-1 has been used in a functional assay of multidrug resistance cells and in apoptosis related mitochondrial modifications.