MTTtests

MTT tests, also known as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, are a common colorimetric method used to assess cell metabolic activity. This assay is widely employed in biological research to determine cell viability, proliferation, and drug cytotoxicity. The principle behind MTT tests relies on the ability of metabolically active cells to reduce MTT, a yellow tetrazolium salt, into formazan crystals, which are purple in color. This reduction is carried out by mitochondrial reductase enzymes present in living cells.

The procedure typically involves incubating cells with MTT solution for a specific period. Subsequently, the formazan crystals are dissolved using an appropriate solvent, such as isopropanol or DMSO. The resulting purple solution's absorbance is then measured using a spectrophotometer at a wavelength of around 570 nm. The intensity of the color, and thus the absorbance, is directly proportional to the number of metabolically active cells present. Therefore, higher absorbance values indicate greater cell viability and metabolic activity.

MTT tests are advantageous due to their simplicity, speed, and ability to be performed in a 96-well plate format, allowing for high-throughput screening. However, it's important to note that the assay measures metabolic activity, not necessarily cell death directly. Factors other than cell death, such as changes in mitochondrial function, can influence MTT reduction. It is also crucial to establish appropriate controls, including negative controls (without cells) and vehicle controls (treated with the solvent used for test compounds but without the compound itself), to ensure accurate interpretation of the results.