Propidium iodide is a commonly used stain for dead cells that fluoresces red when bound to DNA. Propidium iodide can also be used as a counterstain in multicolor fluorescence techniques. Supplied with Propidium Iodide ReadyProbes® Reagent, we provide room temperature stable solutions of classic DNA stains in a convenient dropper bottle. Just two drops per milliliter are enough to stain cells.

Also: Propidium Iodide, Fluorspar grade, 12.5X concentration (13.2 µg/mL, 19.7 µM), soluble in water and 1% DMSO.

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Propidium Iodide ReadyProbes® Reagents Features:
•i.e. Use-ready liquid propidium iodide formula
• Rapidly stain dead cells without washing steps
• Ready-to-use liquid formula in convenient dropper bottles—no need to dilute, weigh or pipette
• At room temperature Low stability - placed within the working area or cell culture area for easy access

Classic dead cell staining
Propidium iodide is a classic fluorescent dye that is widely used for dead cells. Cell staining (Figure 1). Exhibits a large enough Stokes shift to allow simultaneous detection of nuclear DNA and FITC or Alexa Fluor® 488-labeled antibodies.

Convenient Packaging
Propidium Iodide ReadyProbes® reagents come in ready-to-use packaging and can be stored directly next to the flow cytometer or in the cell culture laboratory. The ultra-convenient liquid formula in a dropper bottle (Figure 2) enables staining of cells anytime and anywhere. Just add two drops per mL for optimal, bright and clear staining of nuclei for counting.

Multiple Applications
Propidium iodide is impermeable to membranes and can be eliminated from living cells. Therefore, it is often used to identify dead cells in a population. Due to its spectral properties, dsDNA selectivity, and enhanced fluorescence when bound to DNA, propidium iodide is suitable for use with green (Alexa Fluor® 488, FITC, GFP) fluorophores in multicolor experiments. Due to its high affinity for DNA, it is also frequently used for cell counting, detecting apoptosis, and sorting cells based on DNA content.

Usage Recommendations
• In most cases, 2 drops/1×10⁶ cells of Propidium Iodide ReadyProbes® Reagent and An incubation time of 15 to 30 minutes will stain nuclei brightly; however, optimization may be required for some cell types, conditions, and applications. In this case, simply add more or less droplets until the best stain intensity is achieved.
• When combined with nucleic acids, propidium iodide has a maximum fluorescence excitation wavelength of 535 nm and a maximum emission wavelength of 617 nm. Propidium iodide can be excited with a xenon or mercury arc lamp, or with a 488 nm argon ion laser. Typically, propidium iodide fluorescence is detected in the FL2 channel of a flow cytometer.
•As the preferred red nuclear stain for dead cell analysis by flow cytometry, Propidium Iodide ReadyProbes® Reagent is suitable for use with antibody applications.

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