Used in fluorescence microscopy to stain nucleic acids in cells, particularly for visualizing DNA in fixed cells and tissues. It binds to double-stranded DNA and emits strong fluorescence when excited by UV or blue light, making it useful for nuclear counterstaining in combination with other fluorescent markers. Commonly applied in cell biology and microbiology for assessing nuclear morphology and detecting parasites in blood samples. Also employed in flow cytometry for cell cycle analysis due to its DNA-binding specificity.