DiOC2(3) (3,3'-Diethyloxacarbocyanine, iodide) has been used for measuring membrane potentials in bacteria. The green fluorescent dye forms red fluorescent aggregates with increasing membrane potential. The spectral shifting phenomenon has been exploited to measure membrane potential ratiometrically.    &lamda;Ex/&lamba;Em (MeOH) = 482/497 nm  Orange solid soluble in DMSO or DMF  Store at 4°C and protect from light  C21H21IN2O2  MW: 460.31  [905-96-4]