Flow Cytometric Detection of Mitochondrial Membrane Potential

Mitochondrial membrane potential (Δψm) is an important parameter of mitochondrial function and an indicator of cell health. Depletion of Δψm suggests the loss of mitochondrial membrane integrity reflecting the initiation of the proapoptotic signal. Recently, lipophilic cationic fluorescent dyes have been developed to detect Δψm by accumulating in the mitochondrial matrix until the Nernstian equilibrium distribution of lipophilic cations is reached. In this protocol, we applied a cell-permeant, green-fluorescent, lipophilic dye 3,3'-dihexyloxacarbocyanine Iodide (DiOC6(3)) which accumulates in mitochondria due to their large negative membrane potential, it can be applied to monitor the mitochondrial membrane potential using flow cytometric detection.