Product manual
Product use, preparation, operating conditions and storage.
Nucleic-acid stains and labeling reagentsDetection probe
DAPI
Cat. No.QH-60-6004
A DNA-binding dye for nuclear counterstaining of fixed samples and validated DNA detection.
Packs & quotePrepare the sample
Titrate this formulation
Acquire and interpret
Excitation358 nm
Emission460 nm
TargetDNA
Preparation and storage
- Preparation
- Soluble in water or DMSO
- Storage
- Store at 2–8°C, protect from light
Nucleic-acid binding and detection
DAPI and Hoechst dyes give nuclear signal through DNA binding with preference for AT-rich regions. Permeability and nucleic-acid environment affect staining; morphology or total intensity alone does not identify a cell-death mechanism.
Nuclear counterstaining
For nuclear localization in fixed specimens. Validate permeability, amount and timing separately for live-cell use.
Specifications
Product information
- Product name
- DAPI
- Cat. No.
- QH-60-6004
- Product form
- Nucleic-acid stains and labeling reagents
- Target
- DNA
- Pack sizes
- 100 mg
Preparation and properties
- Excitation wavelength
- 358 nm
- Emission wavelength
- 460 nm
- CAS
- 28718-90-3
- Molar extinction coefficient
- 27,000 M⁻¹ cm⁻¹
- Preparation and sample
- Soluble in water or DMSO
- Storage
- Store at 2–8°C, protect from light
Spectral information and detection
Product parameters
Use parameters for the exact catalog number when preparing reagents, setting reagent input or calculating results. Request a lot-specific CoA for test results.
Protocol
Check formulation concentration
Confirm whether the pack is solid, an mM stock or a fold-concentrated solution. Do not reconstitute an existing solution as a solid or interchange molar and fold-concentration units.
Sample and channel
Define live or fixed preparation, check other dyes and channels, and record collection, staining and acquisition times.
Prepare the sample
Handle consistently and gently, retaining intact cells or applying suitable fixation for the objective. Do not pre-fix or permeabilize groups intended for original membrane-integrity assessment.
Titrate this formulation
Use the purchased formulation and instructions for concentration/time series, comparing background, positive separation and saturation.
Acquire and interpret
Set thresholds with unstained and suitable positive controls, matching acquisition settings. Include single-stain compensation or unmixing for multicolor assays.
Request product documentation
Select a document and enter your phone and email. Include the lot number for a CoA.
DAPIQH-60-6004
Spectra and measurement conditions
Spectra, measurement conditions and detection settings for the exact catalog number.
Certificate of analysis (CoA)
Lot-specific test results. Include the lot number from the vial.
Safety data sheet (SDS)
Handling, storage and emergency response information.
Quality and lot information
Unstained control
Establish sample autofluorescence and detection background.
Handling and dose controls
Compare doses and processing steps to assess changes caused by dye, sample loss or exposure.
References
Nucleic-acid stain binding and membrane permeability
Thermo Fisher Scientific · Molecular Probes Handbook · Section 8.1
Distinguishes DNA preference, membrane permeability and suitable readouts among nucleic-acid stains.
Frequently asked questions
Can DAPI use Hoechst live-cell conditions directly?
DAPI is presented primarily for fixed-sample nuclear counterstaining. Validate permeability, amount and acquisition time separately in live cells; a similar blue channel does not establish equivalence to Hoechst.
Does nuclear positivity or fragmentation alone prove apoptosis?
Nuclear signal reflects DNA binding and accessibility. Interpret morphology with membrane integrity, time courses and independent cell-death readouts.
Can it be combined directly with another blue-channel dye?
Check separation using actual excitation, emission and filters, with single-stain and unstained controls. Similar colors do not imply independently resolvable signals.