HOE 33342 trihydrochloride is widely used in biological research as a fluorescent dye for staining DNA in live and fixed cells. It is particularly valuable in flow cytometry and fluorescence microscopy due to its ability to penetrate cell membranes and bind specifically to DNA, emitting a strong blue fluorescence when excited by UV light. This property makes it an essential tool for studying cell cycle dynamics, apoptosis, and chromatin structure. Additionally, it is employed in cell viability assays, where it helps distinguish between live and dead cells based on differential staining patterns. Its application extends to neuroscience research, where it is used to label neuronal nuclei in brain tissue studies. The dye’s stability and specificity make it a reliable choice for quantitative and qualitative analysis of cellular DNA content.