Cell viability & cytotoxicity assay : Cell Counting Kit-8

• Colorimetric microplate assay
• Ready-to-use one-bottle solution
• No radioisotope or organic solvent required
• No toxicity to cells
• No harvesting, washing or solubilization step required
• More sensitive than MTT, XTT, MTS or WST-1

Cell Counting Kit-8 (CCK-8) allows convenient assays using Dojindo's tetrazolium salt, WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)- 2H tetrazolium, monosodium salt), which produces a water-soluble formazan dye upon bioreduction in the presence of an electron carrier, 1-Methoxy PMS.

CCK-8 solution is added directly to the cells; no pre-mixing of components is required. CCK-8 is a sensitive nonradioactive colorimetric assay for determining the number of viable cells in cell proliferation and cytotoxicity assays. WST-8 is bioreduced by cellular dehydrogenases to an orange formazan product that is soluble in tissue culture medium. The amount of formazan produced is directly proportional to the number of living cells.

The detection sensitivity of cell proliferation assays using WST-8 is higher than assays using the other tetrazolium salts such as MTT, XTT, MTS or WST-1. Since the CCK-8 solution is very stable and it has little cytotoxicity, a longer incubation, such as 24 to 48 hours, is possible.