CellTiter-Fluor(TM) Cell Viability Assay

The CellTiter-Fluor Cell Viability Assay is a non-lytic, single-reagent-addition fluorescence assay that measures the relative number of viable cells in a population. Based on measurement of a conserved and constitutive protease activity within live cells and therefore serving as a biomarker of cell viability, the live-cell protease activity is restricted to intact viable cells and is measured using a fluorogenic, cell-permeant, peptide substrate (Gly-Phe-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. The live-cell protease becomes inactive upon loss of membrane integrity and leakage into the surrounding culture medium. Data from the assay can serve as an internal control and allow identification of errors resulting from cell clumping or compound cytotoxicity.