Spectral Properties of Acridine Orange Bound to Dna/rna

DNA/RNA, present in almost every cell, has been a hot research topic in a wide range of areas, including biology, physics, chemistry and polymer engineering. Naturally, to image DNA and facilitate DNA/RNA-related questions becomes an interesting question itself. Since 50 years ago people have been discovering and developing families of fluorescence dyes (from Acridine orange to YOYO-1) with unique spectral properties towards facilitating single molecule imaging and operation. Acridine orange (AO) has been popular since the DNA/RNA research was initiated. AO intercalates into DNA at low dye/base pair (bp) ratio, showing enhanced green fluorescence, at the same time absorption spectra red shift and absorption band width narrowing. In contrast, AO self-associates with RNA or denatured DNA at high dye/bp ratio, showing red fluorescence. The absorption and emission spectra could be obtained with UV/Visible spectrometer and spectrofluorometer, respectively. Even now Acridine orange has still been used in prion disease inhibition and immune cell DNA/RNA contents quantification, thanks to its affinity to DNA from planar molecular structure and multi-color fluorescence properties.