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To Purchase # 9095S

9095S 1 Kit (1000 assays (96 well format)) $259.00
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Product Includes Quantity (with Count) Solution Color
XTT Reagent 2 x 25 ml Yellowish
Electron Coupling Solution 2 x 0.5 ml Yellow

Product Description

The XTT Cell Viability Assay Kit is a colorimetric assay that detects the cellular metabolic activities. During the assay, the yellow tetrazolium salt XTT is reduced to a highly colored formazan dye by dehydrogenase enzymes in metabolically active cells. This conversion only occurs in viable cells and thus, the amount of the formazan produced is proportional to viable cells in the sample. The formazan dye formed in the assay is soluble in aqueous solution and can be quantified by measuring the absorbance at wavelength 450 nm using a spectrophotometer. An electron coupling reagent, such as PMS (N-Methylphenazonium methyl sulfate), can significantly improve the efficiency of XTT reduction in cells.


Specificity / Sensitivity

The XTT Cell Viability Kit detects formazan dye produced from XTT conversion by mitochondrial enzymes in cells. Because these mitochondrial enzymes are inactivated shortly after cell death, the orange colored formazan dye only appears in viable cells. This XTT Cell Viability Kit is expected to work in most cells lines. Variable with cell type and incubation time employed in the assay, 0.2-2x104 cells/well should be sufficient for most experiments. For the best result, a cell number titration (as shown in Figure 1) is recommended.


Cell viability and proliferation assays are widely used in drug discovery for the study of growth factors, cytokines, and cytotoxic agents. High throughput screening, in early drug discovery compound screening and in later drug safety and toxicity studies, requires a reliable, sensitive, and simple assay with the ability to analyze a large number of samples. Colorimetric cell viability assays using tetrazolium salt, such as MTT, XTT, WST-1, etc. were developed based on live cells reduction of tetrazolium salt into highly colored formazan compounds (1,2). In contrast to cell proliferation assays, such as radioactive thymidine or BrdU labeling of DNA in live cells followed by quantification of the incorporated thymidine (by quantifying sample radioactivity) or BrdU (using anti-BrdU antibody), the XTT assay doesn’t require radioactive materials, cell fixing, or cell permeabilization. Thus, unlike alternative cellular analysis assays, cells examined in the XTT assay may be used for further analysis.


1.  Scudiero, D.A. et al. (1988) Cancer Res 48, 4827-33.

2.  Roehm, N.W. et al. (1991) J Immunol Methods 142, 257-65.



For Research Use Only. Not For Use In Diagnostic Procedures.
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