Fluorescence lifetime-based discrimination and quantification of cellular DNA and RNA with phase-sensitive flow cytometry.

Background: Simultaneous measurement of cellular DNA and RNA content provides information for determination of the functional status of cells and, clinically, for the diagnosis and grading assessment of various tumors. Most current flow cytometric methods are based on resolving the fluorescence emission spectra of dyes that bind preferentially to either type of nucleic acid. However, several monochromatic nucleic acid-binding fluorochromes display resolvable differences in fluorescence lifetime when bound to DNA or RNA.