7-Aminoactinomycin D (7-AAD) is widely used in biological research for its ability to bind to DNA, making it a valuable tool in cell biology and immunology. It is commonly employed in flow cytometry to distinguish between viable and non-viable cells. By selectively staining dead or dying cells with compromised membranes, 7-AAD helps researchers assess cell viability and apoptosis in various experimental setups. Additionally, it is used in combination with other fluorescent markers to study cell cycle dynamics, as it can intercalate into double-stranded DNA and provide insights into cellular DNA content. This makes it particularly useful in cancer research, where understanding cell proliferation and death is critical. Its application extends to immunophenotyping, where it aids in identifying specific cell populations in complex mixtures, such as blood or tissue samples. Overall, 7-AAD is a versatile reagent in life sciences, contributing to advancements in cellular analysis and disease research.