The following protocol uses the MTT colorimetric assay as a classic literature-established method for assessing cell viability/metabolic activity in cultured mammalian cells. MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] is reduced by metabolically active cells to a colored formazan product; the amount of formazan is quantified spectrophotometrically and provides an indirect measure of metabolically active viable cells. Importantly, MTT reduction reflects cellular oxidoreductase/metabolic activity rather than an absolute direct count of living cells, so changes in cellular metabolism can alter the signal independently of cell number.
Cell Viability
Cell viability assays aim to evaluate metabolic activity, proliferative capacity, and cytotoxic responses to drugs, providing quantitative data for drug screening and toxicological research. Common techniques include the MTT/MTS assay (measuring mitochondrial dehydrogenase activity), the trypan blue exclusion assay (distinguishing between live and dead cells), the ATP luminescence assay (quantifying viable cells based on ATP content), flow cytometry (using PI/Annexin V double staining to identify apoptosis and necrosis), and the colony formation assay (assessing long-term proliferative capacity).
Related Experimental Schemes
