ReadiUse™ WST-8 *50 mM aqueous solution*

WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) is a water-soluble tetrazolium salt used for assessing cell metabolic activity. At neutral pH and in the presence of the intermediate electron acceptor, 1-methoxy phenazine methosulfate, NADPH-dependent cellular oxidoreductases, acting via plasma membrane electron transport, reduce the colorless cell-impermeant WST-8 outside the cell to a water-soluble orange formazan dye with absorbance max at 460 nm. WST-8 is very stable, and tolerates a long time incubation (such as 24 to 48 hours) due to its little cytotoxicity. WST-8 allows sensitive colorimetric assays for the determination of the number of viable cells in the proliferation and cytotoxicity assays. The detection sensitivity is higher than any other tetrazolium salts such as MTT, XTT or MTS. It is typically used as a cell viability indicator in cell proliferation assays.