FLIPR® Calcium Assays

Calcium flux assays are preferred methods in drug discovery for screening G protein coupled receptors (GPCRs). Cells expressing a GPCR of interest that signals through calcium are pre-loaded with our proprietary Fluo-8^® AM or Rhod-4™ AM which can cross cell membrane. Screen Quest™ Calcium Assay Kits provide an optimized assay method for monitoring GPCRs and calcium channels. The assay can be performed in a convenient 96-well or 384-well microtiter-plate format and easily adapted to automation.

Fluo-8^® AM is the brightest calcium indicator available for HTS screening. The characteristics of the convenient 488 nm excitation, high sensitivity, and 100-250 times fluorescence increases (when it forms complexes with calcium) make Fluo-8^® AM an ideal indicator for the measurement of intracellular calcium.

Rhod-4™ AM is the brightest red calcium indicator available for HTS screening. Once inside the cell, the lipophilic blocking groups of Rhod-4™ AM are cleaved by non-specific cell esterase, resulting in a negatively charged fluorescent dye that stays inside cells, and its fluorescence is greatly enhanced upon binding to calcium. When cells stimulated with screening compounds, the receptor signals the release of intracellular calcium, which greatly increases the fluorescence of Rhod-4™. The characteristics of its long wavelength, high sensitivity, and >250 times fluorescence increases (when it forms complexes with calcium) make Rhod-4™ AM an ideal indicator for the measurement of intracellular calcium.
Screen Quest™ Fura-2 No Wash Calcium Assay Kit provides the only ratiometric FLIPR^® calcium assay commercially available for screening GPCRs and calcium channel targets. The Fura-2 kit uses excitation ratio of 340/380 nm, monitoring emission at 510 nm.