Invitrogen™ FluxOR™ Red Potassium Ion Channel Assay

The assay takes advantage of the permeability of potassium channels to thallium ions. The red fluorescence (560/590 nm) of a thallium-sensitive indicator dye increases as the thallium concentration rises within the cell. The assay can be configured for either imaging or high throughput applications. Features include:

• Large dynamic range—facilitates use in high throughput applications
• Multiplexed enabled—red fluorescence does not interfere with GFP-expressing cells or other green fluorescent assays
• Confirmation of results—green and red potassium ion channel assays can be used together for increased confidence in experimental results
• Optimized format—96- or 384-well, suited for high throughput applications

Similar to the FluxOR™ II Green Potassium Ion Channel Assay, the FluxOR Red Potassium Ion Channel Assay makes use of the permeability of potassium channels to thallium. When potassium channels are opened by a stimulus, extracellular thallium flows down its concentration gradient into the cells, and channel or transporter activity is detected with a proprietary indicator dye pre-loaded into the cells that increases in cytosolic fluorescence in the presence of thallium. In this way, the fluorescence observed using the FluxOR Red assay is an indicator of any ion channel activity or transport process that allows thallium into cells. This fluorogenic signal quantitatively reflects the activity of ion channels and transporters that are permeant to thallium, including hERG, Kir2.1, and other pharmacologically important potassium channels.

The FluxOR Red Potassium Ion Channel Assay provides a concentrated thallium solution and all necessary buffers, allowing maximum target flexibility and ease of operation in a homogenous format that has been demonstrated with cells stably expressing hERG.