MTT Assay: A Reliable Method for Determining Cellular Viability
Cellular viability is an essential parameter for understanding the health and functionality of a variety of cells, including cancer cells, normal cells, and bacteria. The MTT assay is a widely used method for determining cellular viability. This assay involves the use of MTT, a yellow water-soluble tetrazolium salt that is converted into purple formazan crystals by the activity of mitochondrial dehydrogenases. These crystals can be measured using a spectrophotometer or a microplate reader, and the amount of crystals corresponds to the cell viability.
The Principle of MTT Assay
The principle underlying the MTT assay is based on the metabolic activity of the cells. The enzymatic activity of the dehydrogenase enzymes in active cells can metabolize MTT^4+ to formazan crystals, which can be visualized by the naked eye or measured by a spectrophotometer. The amount of purple formazan produced is proportional to the number of living cells present in the sample.
Advantages and Limitations of MTT Assay
The primary advantage of MTT assay is its high sensitivity and specificity for determining cell viability. It can be used to detect small changes in the number of cells, making it useful for monitoring cell proliferation and apoptosis. Additionally, the assay is highly reproducible, requires relatively simple equipment, and can be used to test a variety of cells and tissues. However, there are some limitations to this assay. For example, the MTT assay cannot differentiate between necrotic and apoptotic cells, as the assay only measures the metabolism of living cells. Additionally, the assay requires a relatively long incubation period, usually taking over 2-4 hours for the formazan crystals to develop.
Applications of MTT Assay
The MTT assay has several applications in a variety of fields, including drug discovery, cancer research, and toxicology. It can be used to screen for potential drug candidates by measuring the effect of the drug on cellular viability. Additionally, the assay can be used to determine the cytotoxicity of chemicals or environmental pollutants on cells. The assay has also been used to examine the effect of radiation on cell viability and to assess the efficacy of anticancer agents against malignant cells.
In conclusion, the MTT assay is a reliable and widely used method for determining cellular viability. The assay is simple, sensitive, and reproducible, making it useful for a variety of applications in research and industry. While there are some limitations to the assay, overall it is a valuable tool for monitoring cell health and performance.
