Cell Proliferation

Cell proliferation is one of the important physiological functions of living cells and is an important life characteristic of organisms. Cell proliferation is the basis of organism growth, development, reproduction as well as heredity.

Normal cells are metabolically vigorous and their mitochondria contain succinate dehydrogenase, which can reduce tetrazolium salts (e.g., MTT, XTT, WST-1, and WST-8, etc.) to purple crystalline substances that deposit around the cell. Then we can use a microplate reader to read the OD value (optical density), thus detecting the status of cell proliferation.

Cell counting kit-8 (also known as CCK-8) is a rapid and highly sensitive assay based on WST-8 (Water Soluble Tetrazolium-8) and widely used for cell proliferation analysis.

The mechanism is: WST-8 [chemical name: 2-(2-Methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium Sodium Salt] is reduced by dehydrogenases in cells under the reaction of the electron carrier 1-methoxy-5-methylphenazinium sulfate dimethyl ester (1-methoxy PMS) to a highly water-soluble yellow formazan product (formazan dye).The number of formazans generated directly correlates to the number of living cells.This property can therefore be exploited to directly carry out cell proliferation assays.The more rapidly the cells proliferate and the more cells proliferate, the darker the color is. For the same cells, there is a linear relationship between the intensity of the color and the number of cells.