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Molecular Probes™ Propidium Iodide
Description
Propidium iodide (PI) is a popular red-fluorescent nuclear and chromosome counterstain. Since propidium iodide is not permeant to live cells, it is also commonly used to detect dead cells in a population.
PI binds to DNA by intercalating between the bases with little or no sequence preference. In aqueous solution, the dye has excitation/emission maxima of 493/636 nm. Once the dye is bound, its fluorescence is enhanced 20- to 30-fold, the fluorescence excitation maximum is shifted ∼30–40 nm to the red and the fluorescence emission maximum is shifted ∼15 nm to the blue, resulting in an excitation maximum at 535 nm and fluorescence emission maximum at 617 nm.
PI is widely used in fluorescence microscopy, confocal laser scanning microscopy, flow cytometry, and fluorometry.
Specifications
Specifications
| Physical Form | Solid |
| Quantity | 100 mg |
Frequently Asked Questions (FAQs)
Oxygen content should not affect the binding of propidium iodide and SYTO 9 to nucleic acids. SYTO 9 will label all cells, and propidium iodide will label only dead cells or cells with a compromised membrane.
Unfortunately, no. SYTO 9 will label the nuclei of live or dead cells, including the eukaryotic cells. Propidium iodide is cell impermeant, and will only enter dead cells. If the eukaryotic cells are dead, they will label with propidium iodide as well. If the eukaryotic cells are alive, propidium iodide will not be able to enter and thus will not label the bacteria inside, whether the bacteria are alive or dead. We are not aware of any way to do a viability assay of bacteria once they have been engulfed by cells.
PI is not fixable with glutaraldehyde or PFA. Both reagents fix by crosslinking amines. PI and other nucleic acid stains do not inherently bind covalently to nucleic acids and these fixatives do not crosslink the dyes to nucleic acids.
The one fixable nucleic acid stain is Ethidium Monoazide Bromide (EMA), Cat no. E1374); it covalently binds to nucleic acids upon activation by exposure to light.
For Research Use Only. Not for use in diagnostic procedures.
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