The MTT Cell Proliferation Assay is based on the reduction of a yellow tetrazolium salt (3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide or MTT) to purple formazan crystals by metabolically active cells. This colorimetric assay is used to measure cellular metabolic activity as an indicator of cell proliferation, viability and cytotoxicity.
The viable cells contain NADPH-dependent oxidoreductase enzymes, which reduce the MTT to formazan.
The insoluble formazan crystals are dissolved using a solubilization solution and the resulting-colored solution is quantified by measuring absorbance at 570 nm while background absorbance at 630 nm, using a multi-well spectrophotometer. The darker the solution, the greater the number of viable and metabolically active cells.
