Product overview

Name Propidium Iodide
Alternative names PI
Biological description

Propidium iodide (PI) is a widely used red-fluorescent intercalating agent that binds and labels nucleic acids.

Propidium iodide is membrane impermeant and is therefore frequently used to selectively identify dead cells and is commonly used in flow cytometry to evaluate cell viability.

Propidium iodide (PI) is often used in flow cytometry, fluorescent microscopy and confocal laser scanning microscopy applications.

Frequently used with Oxazole Yellow (YP1) when staining for apoptotic and necrotic cells as apoptotic cells remain impermeant to propidium iodide but permeable to Oxazole Yellow (YP1).

Once bound to the nucleic acids, its fluorescence is enhanced 20- to 30-fold. Wavelength Maxima: Excitation ~535nm, Emission ~617nm

Purity >97%

Red-fluorescent cell viability stain

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Propidium Iodide product vial image | Hello Bio
Figure 1. Vimentin and Propidium Iodide co-staining in HEK293T cells
Figure 2. Vimentin and Propidium Iodide co-staining in HEK293T cells.
Figure 3. Vimentin and Propidium Iodide co-staining in HEK293T cells
Figure 4. Vimentin and Propidium Iodide co-staining in HEK293T cells.

Biological Data

Application notes

#Protocol 1: Propidium Iodide counterstaining of HEK293T cells

  • HEK293T cells were cultured on coverslips in 10% FBS in DMEM and fixed with 4% PFA. Immunocytochemistry was performed following our ICC protocol using an anti-vimentin monoclonal antibody at 1µg/ml.
  • Prodidium iodide working solution was prepared consisting of 1µg/ml Propidium Iodide and 10µg/ml RNase A and incubated with cells for 30 minutes at room temperature.
  • Following washing with PBS, coverslips were mounted and imaged using a confocal microscope using either a 532nm or 514nm laser for excitation 

Solubility & Handling

Storage instructions +4°C
Solubility overview Soluble in water (5 mM)
Important This product is for RESEARCH USE ONLY and is not intended for therapeutic or diagnostic use. Not for human or veterinary use.



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Chemical Data

Purity >97%
Chemical name 2,7-Diamino-9-phenyl-10 (diethylaminopropyl)-phenanthridium iodide methiodide
Molecular Weight 668.39
Chemical structure Propidium Iodide  [25535-16-4] Chemical Structure
Molecular Formula C27H34I2N4
CAS Number 25535-16-4
PubChem identifier 104981
SMILES CC[N+](C)(CC)CCC[N+]1=C2C=C(C=CC2=C3C=CC(=CC3=C1C4=CC=CC=C4)N)N.[I-].[I-]
MDL number MFCD00011921
Appearance Purple solid
Excitation 535nM
Emission 617nM

References for Propidium Iodide

References are publications that support the biological activity of the product
  • The DNA intercalators ethidium bromide and propidium iodide also bind to core histones.

    Banerjee A et al (2014) FEBS Open Bio 4 : 251-9.
  • Analysis of apoptosis by propidium iodide staining and flow cytometry.

    Riccardi C et al (2006) Nat Protoc 1(3) : 1458-61.
  • DNA staining for fluorescence and laser confocal microscopy.

    Suzuki T et al (1997) J Histochem Cytochem 45(1) : 49-53.

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