CellTiter-Fluor™ Cell Viability Assay Technical Bulletin

Literature # TB371

The CellTiter-Fluor™ Cell Viability Assay is a nonlytic, single-reagent-addition fluorescence assay that measures the relative number of live cells in a culture population after experimental manipulation. The CellTiter-Fluor™ Cell Viability Assay measures a conserved and constitutive protease activity within live cells and therefore serves as a marker of cell viability. Results obtained using the CellTiter-Fluor™ Cell Viability Assay correlate well with other established methods of determining cell viability. The live-cell protease activity is restricted to intact viable cells and is measured using a fluorogenic, cell-permeant, peptide substrate (glycylphenylalanyl-aminofluorocoumarin; GF-AFC). The substrate enters intact cells where it is cleaved by the live-cell protease activity to generate a fluorescent signal proportional to the number of living cells. This live-cell protease becomes inactive upon loss of cell membrane integrity and leakage into the surrounding culture medium.