Propidium iodide cannot be used in live cell imaging as it is impermeant to live cell membranes. The dye is utilized to detect only dead cells in a given population, in order to assess cell viability and measure DNA content. However, a study in recent years was carried out by Paula Szalai and Nikolai Engedal in which PI was used for real-time cell death assessment by automated imaging using the IncuCyte ZOOM from Essen Bioscience system.