CyQUANT XTT Cell Viability assay is colorimetric microplate assays used to measure the metabolic activity of cells, which is an indicator of cell viability, proliferation, and cytotoxicity. CyQUANT XTT function as cell health indicators by using the cellular redox potential of live cells to convert a tetrazolium-based salt reagent, XTT, to a brightly colored formazan product. The absorbance of the formazan can be measured using a microplate reader and correlates with the number of metabolically active cells to quantitively measure cell viability and proliferation.
The CyQUANT XTT assay relies on the reduction of the water-soluble, yellow tetrazolium salt XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) to a water-soluble orange formazan product by metabolically active cells. Unlike MTT, XTT does not form insoluble crystals and produces a soluble formazan product that does not require solubilization. Since no cell lysis or solubilization are required for detection, the XTT assay can be used as a continuous assay, and multiple time points can be analyzed using an absorbance-based microplate reader.
In addition to the XTT Reagent, the CyQUANT XTT Cell Viability Assay kit includes electron coupling reagent to improve the dynamic range of the assay. The sensitivity and consistency of the assay is significantly increased when the electron coupling reagent is used with the CyQUANT XTT assay kit.