Cell Proliferation /Cytotoxicity/Viability Detection

Cell Counting Kit-8（CCK-8) is a rapid and highly sensitive kit based on WST-8, which is widely used in the detection of cell activity and cytotoxicity.

Wst-8 is a compound similar to MTT. In the presence of electron carrier, WST-8 can be reduced by dehydrogenase in mitochondria to form water-soluble orange-yellow dark (Formazan) products, and the amount of Formazan produced is proportional to the number of viable cells. The more and faster the cell proliferation, the darker the color is. The amount of viable cells can be calculated indirectly by measuring the absorbance at 450 nm.

Because the CCK-8 solution is very stable and has little cytotoxicity, longer incubation periods, such as 24 to 48 hours, can be performed. The detection sensitivity of the CCK-8 kit is higher than that of any other tetrazolium salt, such as MTT, XTT or MTS.

Lactate dehydrogenase (LDH) is a kind of oxidoreductase that only exist in cytoplasm of all kinds of cells, it can be released into supernatant during the process of cell death or damage. The quantitation of cytotoxicity can be measured by measuring the extracellular LDH activity through enzymetic reaction.

LDH catalyzes the reaction of lactic acid with NAD+ to produce pyruvic acid and NADH. Under the action of PMS, electrons are transfered from NADH to WST-8 to produce the yellow formazan dye which has a characteristic absorption peak at 450 nm.