MTT Cell Proliferation Assay is based on the transformation and colorimetric quantification of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. The respiratory chain and other electron transport systems reduce MTT and other tetrazolium salts. As a result, non-water-soluble violet formazan crystals accumulate within the cell. The amount of these crystals can be determined using a spectrophotometer, serving as an estimate of the number of mitochondria and, hence, the number of living cells in the sample. These features allow performing cytotoxicity or cell proliferation assays.
The principle of the MTT Cell Proliferation Assay is based in mitochondrial activity. For viable cells, mitochondrial activity is constant and thereby an increase or decrease in the number of viable
cells is linearly related to mitochondrial activity.
You can follow two protocols for this assay:
- In MTT – A protocol is necessary to remove the cell medium before resuspending MTT crystals formed.
- Using MTT – B protocol, the resulting formazan crystals are directly redissolved without removing the culture medium. This kit is suitable for cells in suspension and faster, but less sensitive, than MTT Cell Proliferation Assay A.