Cell Counting Kit-8 (CCK-8) is a fast, highly sensitive assay based on the WST-8 reagent, an improved alternative to MTT. WST-8 is reduced by mitochondrial dehydrogenases in living cells to form a water-soluble orange-yellow formazan dye. The amount of formazan, measured by absorbance at 450 nm using a microplate reader, is directly proportional to the number of viable cells. CCK-8 is widely used in drug screening, cell proliferation and cytotoxicity assays, tumor drug sensitivity testing, and evaluating the activity of biological factors.
