How do I dissolve propidium iodide (PI)?

Propidium iodide (PI) can be dissolved in several different solvents and the solvent you choose depends on the stock solution you are making. you can dissolve it in organic solvents like ethanol, DMSO, and dimethyl formamide. The solubility in these solvents is .2, 2.5, and 3.3 mg/ml respectively. You can also dissolve PI into aqueous buffers such as PBS, and the solubility of PI in PBS is 2mg/ml. Furthermore, you can dissolve PI in deionized water, and its solubility in water is 1mg/ml. For each of these stock solutions, you must store the PI at 4 degrees Celsius, and protect them from light. Those stock solutions will then be good for use for 6 months.