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 (λem=527nm) at low concentrations or at low membrane potential. Alternative name: 5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide. Purity: ≥98% (HPLC). Solubility: Soluble in DMSO or methanol. Long Term Storage: +4°C.