| Hoechst 33342 is a blue fluorescent dye that stains cell nuclei and can penetrate cell membranes. In its free state, Hoechst 33342 exhibits weak or nearly no fluorescence (maximum excitation wavelength at 346 nm and maximum emission wavelength at 460 nm). When Hoechst 33342 binds to the A-T-rich regions of double-stranded DNA, it emits blue fluorescence under UV excitation (maximum excitation wavelength at 350 nm and maximum emission wavelength at 461 nm). Live cells have a certain ability to uptake Hoechst 33342, while apoptotic cells, due to increased membrane permeability, take up more of the dye and thus exhibit stronger fluorescence. Therefore, by detecting fluorescence intensity, it is possible to distinguish live, apoptotic, and necrotic cells. Hoechst 33342 staining is commonly used for apoptosis detection, cell cycle analysis, and cell viability assessment. |
