Product manual
Product use, preparation, operating conditions and storage.
Nucleic-acid stains and labeling reagentsDetection probe
PI
Cat. No.QH-60-6021
Detect accessible nucleic acids after membrane damage for membrane-integrity analysis.
Packs & quotePrepare the sample
Titrate this formulation
DNA-content application
Excitation535 nm
Emission615 nm
TargetAccessible DNA and RNA
Preparation and storage
- Preparation
- Soluble in water or DMSO
- Storage
- Store at 2–8°C, protect from light
Nucleic-acid accessibility and membrane integrity
These dyes poorly enter intact cells but give stronger nucleic-acid signal after membrane damage. Fixation and permeabilization also expose nucleic acids, so staining afterward does not report original viability.
Membrane-integrity analysis
Compare unfixed cells with known live/dead controls. Membrane-compromised positivity alone does not distinguish apoptosis from other death mechanisms.
Specifications
Product information
- Product name
- PI
- Cat. No.
- QH-60-6021
- Product form
- Nucleic-acid stains and labeling reagents
- Target
- Accessible DNA and RNA
- Pack sizes
- 5 mg
Preparation and properties
- Excitation wavelength
- 535 nm
- Emission wavelength
- 615 nm
- CAS
- 25535-16-4
- Molar extinction coefficient
- 6,000 M⁻¹ cm⁻¹
- Quantum yield
- 0.2
- 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.
DNA-content application
PI also binds RNA. DNA-content analysis needs its own fixation, RNase treatment and singlet-gating workflow, distinct from original live/dead assessment.
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.
PIQH-60-6021
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.
Known live/dead controls
Match collection and acquisition to define intact and compromised populations, recording acquisition delay.
References
Membrane-integrity dyes and viability methods
Thermo Fisher Scientific · Molecular Probes Handbook · Section 15.2
Explains nucleic-acid dyes in membrane-integrity assays and considerations for combined controls.
Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)
Cossarizza A, Chang HD, Radbruch A, et al. · European Journal of Immunology · 51(12):2708–3145 · 2021
Provides methodological guidance on detection settings, controls and experimental records for downstream conjugate evaluation.
Frequently asked questions
Do PI viability and DNA-content assays use the same workflow?
Assess original membrane integrity in unfixed cells. DNA-content analysis needs appropriate fixation, RNase treatment and singlet gating because PI also binds RNA. Positivity has different meanings in the two workflows.
Is fixation required for detection?
Assess original membrane integrity in unfixed samples; post-fixation staining cannot reconstruct it.
Can it replace a Cell-Life fixable viability workflow?
This stain reports nucleic-acid accessibility and does not directly replace covalent amine-reactive labeling before fixation. If later fixation or permeabilization is needed, validate whether the original membrane state can be retained and interpreted.