ACRIDINE ORANGE For Microscopical Staining Basic Orange 14, Euchrysine, N,N,N’,N’- Tetramethylacridine-3,6-diamine C.I.No.46005 Riboneucleic acid stain -Acridine orange (AO) is a nucleic acid selective fluorescent cationic dye useful for cell cycle determination. It is cell-permeable, and interacts with DNA and RNA by intercalation or electrostatic attractions.It is also useful as a non-specific stain for backlighting conventionally stained cells on the surface of a solid sample of tissue (fluorescence backlighted staining)