How do I determine cell viability?

Cell viability can be determined a number of different ways such as measuring the mitochondrial membrane potential or the cellular redox potential. However, the two most common methods for assessing cell viability are to measure the membrane integrity or metabolic activity of a cell.

• Membrane integrity – this technique typically uses cell-impermeant nucleic acid stains to measure membrane integrity. Viable cells with healthy, intact membranes will exclude the dye, while dead cells or cells with compromised membranes will take up the dye and become stained.
• Metabolic activity – this technique uses cell permeable esterase substrates to measure intracellular enzyme activity. Healthy cells, with active esterases, will hydrolyze the substrate into a fluorescent byproduct.