MitoView™ dyes are fluorogenic mitochondrial stains for live cells. The dyes rapidly accumulate in mitochondria and can be imaged without washing. They are available with blue, green, far-red, and near-infrared fluorescence.  MitoView™ 633 is a far-red fluorescent mitochondrial dye with absorbance/emission at 622/648 nm. The dye is membrane permeable and becomes brightly fluorescent upon accumulation in the mitochondrial membrane. Staining is dependent on mitochondrial membrane potential, and can be used to monitor mitochondrial membrane potential in intact cells. The dye is designed for use in live cells, and is not fixable. Note: The optimal detection settings for MitoView™ 633 are the same as for Cy®5 and other far-red dyes. However, the dye also has visible red fluorescence and can be imaged using Cy®3 settings as well. As a consequence, the dye cannot be used for two-color imaging with other red probes.  In addition to MitoView™ dyes, Biotium also offers several classical dyes for measuring mitochondrial membrane potential. These include JC-1, a ratiometric dye that forms red aggregates in healthy cells, which are reduced to the green monomeric state when mitochondrial membrane potential is lost. We also offer TMRM and TMRE, two red fluorescent dyes that are used to quantitatively measure mitochondrial membrane potential using the Nernst equation.  Cy Dye is a registered trademark of GE Healthcare.