Propidium Iodide (ultra pure)

Propidium iodide (PI) belongs to the same chemical class as ethidium bromide. As with ethidium bromide, its fluorescence is enhanced 20-30-fold upon binding to nucleic acids. The fluorescence excitation maximum is red-shifted 30-40 nm and the fluorescence emission maximum blueshifted ~15 nm. PI also binds to RNA as does DAPI and acridine orange. PI is membrane impermeant and is commonly used for identifying dead cells in a mixed population of cells and as a counter-stain in multicolor fluorescent techniques. It can also be used to differentiate necrotic, apoptotic and viable cells. The dye is suitable for fluorescence microscopy, flow cytometry and fluorometry applications. Wavelength Maxima: Excitation 535nm, Emission 617nm