DiSC3(5) is a lipophilic cationic fluorescent probe sensitive to changes in membrane potential. 3,3'-Dipropylthiadicarbocyanine iodide accumulates in hyperpolarized cell membranes, leading to fluorescence quenching; when the membranes are depolarized, the dye is released from the cells and the fluorescence intensity is enhanced, which is used for real-time monitoring of mitochondrial membrane potential changes and membrane hyperpolarization. The maximum excitation/emission wavelength was 622/670 nm.