Propidium Iodide
PI (Ex-Max 535 nm/Em-Max 617 nm)
Propidium Iodide (PI) is an orange/red-emitting DNA intercalating dye that can be excited by the 532 nm green laser and captured with a 630/69 nm bandpass filter. Unbound, PI has an excitation peak at 493 nm and an emission peak at 636 nm. However, when PI is bound to DNA the excitiaton peak shifts to 535 nm and the emission peak shifts to 617 nm. PI is predominantly used in flow cytometry as a DNA stain evaluate cell viability or to monitor cell cycle analysis, or in microscopy to visualize the nucleus and other DNA-containing organelles. PI is a generic dye that is sold by multiple suppliers.
Excitation & emission spectra
Key facts
- Excitation maximum
- 535 nm
- Emission maximum
- 617 nm
- Optimal laser line
- 488-532
- Optimal filter
- 630/69
- Extinction coefficient
- 6000
- Molecular weight
- 668
Propidium Iodide has an excitation maximum at 535 nm and an emission maximum at 617 nm, a Stokes shift of 82 nm. Its extinction coefficient is 6000 M⁻¹cm⁻¹. It is optimally excited by the 488-532 laser line.
Frequently asked questions
- What is Propidium Iodide?
- Propidium Iodide (PI) is an orange/red-emitting DNA intercalating dye that can be excited by the 532 nm green laser and captured with a 630/69 nm bandpass filter. Unbound, PI has an excitation peak at 493 nm and an emission peak at 636 nm. However, when PI is bound to DNA the excitiaton peak shifts to 535 nm and the emission peak shifts to 617 nm. PI is predominantly used in flow cytometry as a DNA stain evaluate cell viability or to monitor cell cycle analysis, or in microscopy to visualize the nucleus and other DNA-containing organelles. PI is a generic dye that is sold by multiple suppliers.
- What laser excites Propidium Iodide?
- Propidium Iodide is optimally excited by the 488-532 laser line. Its excitation maximum is 535 nm.
- What filter should I use to detect Propidium Iodide?
- A 630/69 filter captures the peak of the Propidium Iodide emission near 617 nm with minimal spillover.