Most common red-fluorescent nuclear stain. Membrane impermeant and generally excluded from viable cells. It can easily penetrate dead or damaged cells and as such is commonly used for identifying cell viability in a population or as a counterstain in multicolor fluorescent techniques. It binds to DNA and RNA by intercalating between the bases. Suitable for use in fluorescence microscopy, confocal laser scanning microscopy, flow cytometry and fluorometry. Spectral data: lambdaex=488-535nm, lambdaem=617nm.