The CytoTox-Glo™ Assay is a luminescent cytotoxicity assay that measures the relative number of dead cells in cell populations. The CytoTox-Glo™ Assay measures the extracellular activity of a distinct intracellular protease activity (dead-cell protease) when the protease is released from membrane-compromised cells. A luminogenic cell-impermeant peptide substrate (AAF-aminoluciferin) is used to measure dead-cell protease activity. The liberated aminoluciferin product is measured as "glow type" luminescence generated by Ultra-Glo™ Recombinant Luciferase provided in the assay reagent. The AAF-aminoluciferin substrate cannot cross the intact membrane of viable cells and does not generate any appreciable signal from the live-cell population. The amount of luminescence directly correlates with the percentage of cells undergoing cytotoxic stress. With the addition of a lysis reagent (provided), the CytoTox-Glo™ Assay also can deliver the luminescent signal associated with the total number of cells in each assay well. Viability can be calculated by subtracting the luminescent dead-cell signal from the total luminescent value, thus allowing you to normalize assay data to cell number and mitigate assay interferences that may lead to erroneous conclusions. The cytotoxicity protease biomarker is constitutive and conserved across cell lines, and the CytoTox-Glo™ Assay demonstrates excellent correlation with other methods of assessing cell viability.
Features - Benefits
Measure the Relative Number of Dead Cells in Culture: Measure cytotoxicity by adding a single reagent with the homogeneous "add-mix-measure" protocol.
Distinguish Between Small Differences in Viability: The assay provides a linear response and can distinguish between small differences in viability across the entire spectrum of cytotoxicity, from modest cytotoxicity (100 to 95% viability) to profound cytotoxicity (5 to 0% viability).
Normalize Data for Cytotoxicity: Data normalization for dead-cell number makes results more comparable well-to-well, plate-to-plate and day-to-day.
Measure the Relative Number of Remaining Viable Cells Using a Total Lysis Protocol: Correlate increased cytotoxicity with a reduction in viable cells.
Improve your Data: Reduce statistical probability of false-positives (or false-negatives), and eliminate fluorescence interference issues with a stable luminescence readout.
Applications
Cytotoxicity determination.
Total cell number determination.
Multiplexed viability and cytotoxicity.
Notes
Using 100μl/assay in a 96-well plate format, Cat.# G9290 is sufficient to perform 100 assays; Cat.# G9291, 500 assays; Cat.# G9292, 1,000 assays. Using 25μl per well in a 384-well plate format, Cat.# G9290 is sufficient to perform 400 assays; Cat.# G9291, 2,000 assays; Cat.# G9292, 4,000 assays.
References
Niles, A. et al. (2007) Anal. Biochem. 366, 197–206.