Description: | The Cell-Check™ Viability/Cytotoxicity Kit for Animal Cells provides a two-color fluorescence staining on both live and dead cells using two probes that measure two recognized parameters of cell viability — intracellular esterase activity and plasma membrane integrity. The kit is suitable for use with fluorescence microscopes, fluorescence multiwell plate scanners and flow cytometers and other fluorescence detection systems. The assay principles are general and applicable to most eukaryotic cell types, including adherent cells and certain tissues, but not to bacteria or yeast. It is generally faster, less expensive, safer and a more sensitive indicator of cytotoxic events than alternative methods. Live cells are distinguished by the presence of ubiquitous intracellular esterase activity, determined by the enzymatic conversion of the virtually nonfluorescent cell-permeant calcein AM to the intensely fluorescent calcein. The polyanionic dye calcein is well retained within live cells, producing an intense uniform green fluorescence in live cells (Ex/Em ~495 nm/~520 nm). Propidium iodide (PI) enters cells with damaged membranes and undergoes a 30-fold enhancement of fluorescence upon binding to nucleic acids, thereby producing a bright red fluorescence in dead cells (Ex/Em ~528 nm/~617 nm). PI is excluded by the intact plasma membrane of live cells. |