DAPI, 4′,6-diamidino-2-phenylindole, is a blue fluorescent nucleic acid stain that fluoresces brightly upon selectively binding to the minor groove of double stranded DNA. Its selectivity for DNA and high cell permeability allows efficient staining of nuclei with little background from the cytoplasm. The excitation and emission wavelengths of DAPI-DNA complex are 360 nm and 460 nm, respectively. Most of the fluorescent dyes fade (photobleach) when exposed to excitation light. The amount of photobleaching depends on the composition of the molecule and the time of light exposure. DAPI Ready Made Solution with Antifade is a formulation that suppress photobleaching and prolong fluorescent signals.
Synonyms: 4',6-Diamidino-2-phenylindole dihydrochloride; DAPI Dye; DAPI Stain; DNA Content Counterstain; 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride; DAPI dihydrochloride
Molecular Formula: C16H15N5 · 2HCl
Molecular Weight: 350.25
Linear Structural Formula: C16H15N5 · 2HCl
MDL Number: MFCD00012681
Storage: -20C
Application: DAPI is several times more sensitive than ethidium bromide for staining DNA in agarose gels. It may be used for photofootprinting of DNA, to detect annealed probes in blotting applications by specifically visualizing the double-stranded complex, and to study the changes in DNA and analyze DNA content during apoptosis using flow cytometry. DAPI staining has also been shown to be a sensitive and specific detection method for mycoplasma.
Biochem Physiol Actions: Cell permeable fluorescent minor groove-binding probe for DNA. Binds to the minor groove of double-stranded DNA (preferentially to AT rich DNA), forming a stable complex which fluoresces approximately 20 times greater than DAPI alone.