propidium

Propidium Iodide (PI) is a red fluorescent dye utilized for cell staining and is suitable for fluorescence microscopy, confocal microscopy, flow cytometry, and fluorometer analysis. In aqueous solution, the Ex Em of PI is 493 636 nm. Upon binding with nucleic acid, the Ex Em shifts to 535 617 nm, enhancing the fluorescence signal 20-30 times.