Widely used in fluorescence microscopy to visualize nuclear DNA in cells. It binds strongly to the minor groove of double-stranded DNA, emitting bright blue fluorescence when excited by UV light. Commonly applied in cell cycle analysis, apoptosis detection, and nuclear morphology assessment. Compatible with both fixed and live cells, making it valuable in microbiology, cell biology, and cytogenetics. Often used in combination with other fluorescent markers for multicolor imaging. Also employed in counting cell nuclei and confirming successful transfection or cell fusion in culture.