Biotium offers cell proliferation assays to quantitate live or dead cells by absorbance, fluorescence, or luminescence.

• Aassay employs two probes that detect intracellular esterase activity in live cells and compromised plasma membrane integrity in dead cells

Calcein-AM and ViaFluor™ CFSE are initially colorless compounds that are hydrolyzed by cellular esterases to label the cytoplasm with green fluorescence. Calcein-AM and ViaFluor™ CFSE can be used to quantitate viable cells by fluorescence microplate reader. ViaFluor™ CFSE stably labels cells and also can be used to track cell divisions over multiple generations by flow cytometry analysis in the FITC channel. The Cytotoxicity and Viability Assay pairs calcein-AM with the red fluorescent vital dye ethidium homodimer III for quantitation of live and dead cells.

The ATP-Glo cell viability assay uses Firefly luciferase lumenescence to measure cellular ATP levels. ATP-Glo is highly sensitive, and can detect as little as one cell or 0.01 picomole of ATP, with signal linearity for ATP detection within 6 orders of magnitude. ATP-Glo is a flash-type luminescence assay (signal is stable for ~ 1 minute), for use with a single read luminometer or luminescence plate reader with sample injector.

MTT and XTT are reduced by viable cells to form colored formazin salts, which can be measured by absorbance. MTT requires cell lysis prior to measurement, while XTT does not. Resazurin is reduced by viable cells from a dark blue colored compound to a red fluorescent compound, which can be measured by fluroescence or absorbance.