Propidium Iodide (PI) Fluorescence Counterstain Protocol




PI Counterstain Solution:


PI Stock Solution (1mg/ml or 1.5 mM):
To prepare, add 1 mg PI (Propidium Iodide) to 1 ml distilled water. Store stock solution at 4 ºC (or aliquot and store at -20 ºC), protecting from light. When handled properly, solutions are stable for many years.

RNase A Stock Solution (1mg/ml):
To prepare, add 1 mg RNase A to 1 ml distilled water. Aliquot and store at -20 C freezer.

PI Working Solution (1 ug/ml PI and 10 ug/ml RNase A in PBS):
To prepare, add 2 ul PI Stock Solution and 20 ul RNase A Stock Solution to 2 ml PBS


Incubate sections in dark for 30 minutes at room temperature or 20 minutes at 37 ºC.


Staining Pattern


Nuclei will be stained red.


Suggested Use


Counterstaining for immunofluorescence when green (FITC) or blue (AMCA) fluorescent marker is used.