Interaction of propidium iodide with graphene oxide and its application for live cell staining

The fluorescence of propidium iodide (PI) can be effectively quenched with the addition of graphene oxide (GO) in aqueous solution, due to the formation of a physical adsorption material named GO–PI. A fluorescence enhancement of approximately 80 times can be observed after addition of a certain amount of DNA/RNA into the above-mentioned solution. Meanwhile, it is found that the GO–PI can enter into the nuclei and stain the DNA/RNA of living human breast cancer cells MCF-7, while PI alone cannot cross the cellular membrane in the control experiment, demonstrating GO can be employed to be an efficient PI delivery nanomaterial for live cell staining.