Description
DAPI Solid Powder – High-Purity DNA Counterstain for Fixed-Cell Imaging
DAPI (4′,6-Diamidino-2-phenylindole) solid powder from emp BIOTECH is a high-quality fluorescent DNA stain optimized for fixed-cell fluorescence microscopy and cellular imaging applications. This classic nuclear counterstain is essential for cell-based assays that quantify DNA content or visualize nuclei with high specificity.
Upon selective binding to the minor groove of double-stranded DNA, DAPI’s fluorescence increases ~20-fold, enabling bright blue nuclear signals with minimal cytoplasmic background. The dye is highly permeable to fixed cells and compatible with fluorescein- and rhodamine-labeled antibodies, making it ideal for multiplexed fluorescence microscopy.
For live-cell nuclear staining, we recommend Hoechst 33342.
Performance Highlights
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Strong blue fluorescence with minimal background in fixed-cell applications
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Fluorescence intensifies ~20× upon binding to dsDNA
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Excitation: 341 nm (360 nm with dsDNA); Emission: 452 nm (458 nm with dsDNA)
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Compatible with fluorescein- and rhodamine-based probes
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Trusted choice for immunofluorescence and DNA quantification assays
Properties
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CAS Number: 28718-90-3
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Molecular Weight: 350.25
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Empirical Formula: C₁₆H₁₇N₅Cl₂
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Absorption [nm]: 343 ± 3
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Emission [nm]: 444 ± 3
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ε [M⁻¹ cm⁻¹]: >30,000
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Excitation (free dye): 341 nm
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Excitation (with dsDNA): 360 nm
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Emission (free dye): 452 nm
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Emission (with dsDNA): 458 nm
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Buffer System for Fluorescence Readings: H₂O
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Solubility: H₂O
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Appearance (colour): yellow
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Appearance (form): solid (powder)
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Storage: +2 to +8 °C. Keep dry! Protect from light!
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Trade Name: 4′,6-Diamidino-2-phenylindole dihydrochloride; DAPI, Dihydrochloride
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Reactive Moiety: –
Application
Fluorescence microscopy of fixed cells and tissues. Particularly useful for nuclear counterstaining in immunofluorescence and high-content screening.
