Description
Hoechst 33342 – Aqueous Blue DNA Stain for Fixed and Live-Cell Imaging
Hoechst 33342 is a high-quality fluorescent dye formulated for staining DNA in both fixed and live cells. Supplied as a ready-to-use aqueous solution (5 mg/mL in water), it serves as a reliable nuclear counterstain in fluorescence microscopy and cellular imaging applications. This cell-permeable dye preferentially binds to adenine-thymine (A–T) rich regions in the minor groove of DNA and emits bright blue fluorescence when excited by UV light.
With distinct spectral shifts depending on dye-to-base pair ratios, Hoechst 33342 is highly versatile and frequently used in co-staining protocols alongside BrdU, propidium iodide, and fluorophore-labeled antibodies or probes (e.g., fluorescein and rhodamine). It is especially valuable for assessing apoptosis, chromatin compaction, and cell-cycle phases.
Performance Highlights
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Excitation at 346 nm (or 361 nm with dsDNA); emission at 497 nm
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Suitable for both fixed and live cells
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Compatible with multi-stain workflows (e.g., BrdU, PI, FITC, Rhodamine)
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Ideal for apoptosis studies, chromatin visualization, and DNA quantification
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Ready-to-use solution in water, no dilution required
Properties
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CAS Number: 23491-52-3
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Molecular Weight: 615.98
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Empirical Formula: C₂₇H₃₇N₆O₄Cl₃
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Absorption [nm]: 343 ± 3
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Emission [nm]: 497 ± 3
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ε [M⁻¹ cm⁻¹]: >45,000
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Excitation (free dye): 346 nm
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Excitation (with dsDNA): 361 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): solution
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Storage: +2 to +8 °C. Protect from light!
Application
Fluorescence microscopy and nuclear DNA staining for both live and fixed cells. Suitable for use in multicolor imaging protocols and apoptosis or cell-cycle analyses.
