DiO/DPA is a non-invasive optical membrane potential reporter system with low cytotoxicity, high speed, and high sensitivity.

The DiO/DPA system detects cytoplasmic membrane potential changes using the principle of fluorescence resonance energy transfer (FRET). The green fluorescent lipophilic dye DiO acts a stationary FRET donor in the plasma membrane. The anionic quencher DPA acts as a mobile FRET acceptor, rapidly partitioning in and out of the membrane in response to membrane potential, thus modulating DiO fluorescence. The DiO/DPA system has been reported to produce large fluorescence signal changes of >56% in HEK-293 cells and >25% in neuronal cultures and brain slices per 100 mV membrane potential change, and to report membrane potential in situ on submillisecond time scale (see Ref. 1).

The DiOC₁₆(3) in this kit is an improved version over the DiOC₁₆(3) from other suppliers; it is formulated with gluconate as the counter ion to increase dye solubility, for brighter and more uniform cell staining.

DPA is a hazardous material due to its explosive nature. To improve its safety during shipping and handling, it is provided as a dilute solution in the kit. We also offer DPA solid (catalog no. 60037).