| Hoechst 33258 is a blue fluorescent dye that can penetrate the cell membrane and specifically intercalates into AT-rich regions of double-stranded DNA. It exhibits relatively low cytotoxicity and is commonly used for nuclear staining. In its free state, unbound Hoechst 33258 emits very weak fluorescence, almost undetectable (maximum excitation wavelength: 346 nm, maximum emission wavelength: 460 nm). However, once intercalated into double-stranded DNA, its fluorescence properties change: upon excitation, it emits bright blue fluorescence (maximum excitation wavelength: 352 nm, maximum emission wavelength: 461 nm), and the fluorescence intensity increases proportionally with DNA content, allowing for quantitative analysis. Hoechst 33258 is often used in apoptosis detection, and the staining results can be observed under a fluorescence microscope or analyzed by flow cytometry. |
