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AAT Bioquest

Is propidium iodide cell permeable?

Posted October 14, 2022


Answer

Propidium iodide (PI) is a fluorescent dye used to stain cells and nucleic acids. It  is impermeable to cells with an intact plasma membrane. This is so it can be used to differentiate viable cells from dead cells. If the dye is able to stain a cell, that cell is deemed to be dead because it is lacking a membrane.

Additional resources

Propidium iodide staining underestimates viability of adherent bacterial cells

Live or Dead™ Yeast CFDA-AM/Propidium Iodide Vitality Kit