Propidiun iodide (PI) binds to DNA without any sequence preference by intercalating between the base pairs with a stoichiometry of one dye per 4 - 5 base pairs of DNA. When PI binds to DNA the fluorescence emission maxima is shifted to 615–620 nm. PI can be detected in both red as well as yellow fluorescence channel upon excitation by a 488 nm laser. It is used for identification of dead cells as it can penetrate them but not the viable cells.
Propidiun iodide Solution (1mg/ml) is a ready-to-use fluorescent dye used for the staining of
nucleic acids as it intercalates into double-stranded nucleic acids. When PI binds to DNA the
fluorescence emission maxima is shifted to 615–620 nm. PI can be detected in both red as well as yellow
fluorescence channel upon excitation by a 488 nm laser. This reagent is widely used for the
measurement of DNA content during cell cycle analysis and evaluation of cell death and apoptosis as it
penetrates the cell membranes of dead cells but not of the live cells.