Evaluation of PicoGreen variants for use in microscopy and flow cytometry

PicoGreen is a fluorescent probe that binds dsDNA and forms a highly luminescent complex when compared to the free dye in solution. This unique probe is widely used in DNA quantitation assays but has limited application in flow cytometry and microscopy. Here we have investigated various PicoGreen variants for the ability to stain low amounts of cytosolic DNA present in many tumor cells. Analysis of stained cells by flow cytometry and fluorescent microscopy showed that certain variants improved the ability to stain low levels of cytosolic DNA when compared to the commercially available PicoGreen molecule.