Top : Cell Biology : Flow Cytometry (FCM) : PI Staining for FACS Analysis

Summary: Propidium iodide (PI) Staining. PI is an intercalating agent and a fluorescent molecule with a molecular mass of 668.4 Da, when bound to nucleic acids, excitation maximum at 535 nm and the emission maximum at 617 nm. PI is used as a DNA stain for both flow cytometry, to evaluate cell viability or DNA content in cell cycle analysis and microscopy to visualize the nucleus and other DNA containing organelles. Since PI also binds to RNA, it is necessary to treat cells with RNase to distinguish between RNA and DNA staining. PI is a membrane impermeant dye that is generally excluded from viable cells. Therefore, for DNA staining with PI, cells must be fixed or permeabilized to allow entry of the dye. Due to this property, PI staining of unpermeabilized cells followed by flow cytometry can be used to distinguish dead and live cells.
Related Categories: