Dead Cell Discrimination

Abstract

During phenotypic analysis, it is often desirable to exclude dead cells from the analysis as they tend to stain non - specifically and give misleading results. As cells lose their membrane integrity during cell death they become accessible to DNA binding dyes such as propidium iodide, 7 AAD and TO-PRO-3. Propidium iodide (PI) binds to double stranded nucleic acids by intercalating in the double helix. The accessibility is due to deterioration of the membrane during the celll death. The dead cells are hence distinguished from live cells by bright staining with PI. Propidium iodide can be used in multicolour analysis in conjunction in fluorochromes such as FITC with a 488nm laser, with APC (red 635nm Laser) or AMCA (UV excitation). The forward scatter signal is reduced during death in cunjunction with more intense PI staining of the dead cells.