Cell viability assays use a variety of markers as indicators of metabolically active (living) cells. Examples of markers commonly used include measuring ATP levels, measuring the ability to reduce a substrate, and detecting enzymatic/protease activities unique to living cells.
Tetrazolium Reduction Cell Viability Assays
Tetrazolium compounds used to detect viable cells fall into two basic categories:
Positively charged compounds (MTT) that readily penetrate viable cells:
Viable cells with active metabolism are able to convert MTT into a purple-colored formazan product.
Negatively charged compounds (MTS, XTT, WST-1) that do not penetrate cells:
Resazurin Reduction Cell Viability Assay
Resazurin is a cell-permeable indicator dye that is dark blue in color with little intrinsic fluorescence. Only viable cells with active metabolism can reduce resazurin into resorufin, which is pink and fluorescent.
Dead-cell Protease Release Cytotoxicity Assay
When cells die and lose membrane integrity, dead-cell proteases are released. A luminogenic substrate or fluorogenic substrate can then be used to measure dead-cell protease activity. Because the substrate is not cell-permeable, essentially no signal from this substrate is generated by intact, viable cells.
Lactate Dehydrogenase (LDH) Release Cytotoxicity Assays
Dead cells that have lost membrane integrity release lactate dehydrogenase (LDH), which catalyzes the conversion of lactate to pyruvate with the concomitant production of NADH. Released LDH activity can be measured by providing excess substrates (lactate and NAD+) to produce NADH. This NADH can be measured using different assay chemistries.
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This video is about Cell viability assays, Cell viability testing, Assays for cell viability
Cell viability measurement, Viability assays in cell culture, Methods for assessing cell viability, Fluorescence-based viability assays, MTT assay protocol, Alamar Blue assay, Trypan blue exclusion assay, Live/dead cell staining, Cell viability analysis, High-throughput viability screening, Cell viability markers, Viability assays comparison, Cell viability testing, Assays for cell viability, Cell viability measurement, Viability assays in cell culture, Methods for assessing cell viability and Fluorescence-based viability assays.
14 авг 2023
