Cell Viability and Functionality Assays
All assays described on this page are available as contract research services or as assay kits from our on-line catalog
Assessing whether cells are alive or dead is one of the most basic procedures in a cell biology laboratory. Live cells are said to be viable. There are two categories of assays that determine whether cells are viable:
- Dye exclusion viability assays
- Metabolic viability assays
Dye exclusion viability assays detect membrane integrity. These assays include, but are not limited to, trypan blue, propidium iodide (PI), 7-aminoactinomycin D (7-AAD), acridine orange. They are the most widely used viability assays. However, they do not provide information regarding the metabolic status of the cells, that is, whether the cells can actively metabolize reagents or whether they demonstrate mitochondrial integrity by producing intracellular ATP (iATP, the cell's energy source). As a result, dye exclusion viability assays are known to produce false positive results since cells can exhibit high viabilities by dye exclusion, but may be metabolically dead and unable to metabolize agents or produce iATP.
Metabolic viability assays detect the ability of the cells to metabolize agents and/or produce iATP, as an indicator of cellular and mitochondrial integrity. Metabolic viability assays include, but are not limited to, MTT, XTT, BudR, CellQuant™ and iATP. The first three use absorbance as the readout. The fourth uses a fluorescence signal. The last, iATP, is usually measured using a luminescence signal incorporating a luciferin / luciferase reaction where the iATP is rate limiting. When the iATP is measured and the assay is calibrated and standardized with an external ATP standard and controls, HemoGenix® designates this procedure, Bioluminomics™.
HemoGenix® has developed two metabolic viability assays for different applications that incorporate bioluminomics™ technology. These are:
- LIVEGlo™ and
LIVEGlo™ - A Metabolic Cell Viability Assay
LIVEGlo™ is an ATP-based viability assay that can be used as a standalone assay or combined with a dye exclusion viability assay to determine the cellular and mitochondrial integrity of cells in a cell suspension prior to in vitro culture . LIVEGlo™ takes approximately 30 minutes to perform and can be used for virtually any mammalian species, including human, non-human primate, horse, pig, sheep, dog, rat and mouse.
STEMpredict™ - A Hematopoietic Stem Cell Growth and Functionality Assay
The second of the two bioluminomics™-based viability assays is STEMpredict™. STEMpredict™ is an assay developed exclusively for stem cell transplantation and umbilical cord blood processing laboratories. It is used to determine whether stem cells in a mobilized peripheral blood, umbilical cord blood or bone marrow cellular therapeutic product demonstrate growth, cell functionality and viability. A small number of cells are cultured in the STEMpredict™ reagent provided in the assay kit. After 2-3 days, the iATP is measured. The results will show whether the cells are capable of cell growth. STEMpredict™ is the fastest and most sensitive stem cell viability and functionality assay available.