Cytotoxicity is the quality of being toxic to cells. Cells exposed to a cytotoxic compound can respond in a number of ways. The cells may undergo necrosis, in which they lose membrane integrity and die rapidly as a result of cell lysis; they can stop growing and dividing; or they can activate a genetic program of controlled cell death, termed apoptosis.
Cells undergoing necrosis typically exhibit rapid swelling, lose membrane integrity, shut down metabolism, and release their contents into the environment upon lysis. Apoptosis is characterized by well-defined cytological and molecular events, including a change in the refractive index of the cell, cytoplasmic shrinkage, nuclear condensation, and cleavage of DNA.
Cytotoxicity assays are used widely in drug discovery research to help predict which lead compounds might have safety concerns in humans before significant time and expense are incurred in their development. Other researchers study mechanisms of cytotoxicity as a way to gain a better understanding of the normal and abnormal biological processes that control cell growth, division, and death.
There are many ways to measure cytotoxicity, but most involve assessment of cell membrane integrity. Membrane integrity can be evaluated by using vital dyes (such as trypan blue or propidium iodide), by protease biomarkers, with MTT or MTS redox potential assays, or by measuring ATP content. Many of these assays involve colorimetric, fluorescence, or luminescence detection.
With one of the widest ranges of detection technologies on the market today, Molecular Devices can provide the bioanalytical and analytical products that you need to conduct cytotoxicity measurements, from cytometry and high-content screening systems to multi-mode microplate analysis systems to high-throughput cellular screening systems. Please select among the links below to learn more.