Two-Photon Excited Luminescent Styryl Dyes as Probes for the DNA Detection and Imaging. Photostability and Phototoxic Influence on DNA

The photostability and phototoxic influence on DNA of several styryl dyes are investigated by studying the absorption, fluorescence and phosphorescence spectra of these dyes and DNA + dye systems. The dyes Bos-1, DBos-24, and DBos-30 exhibit a rather intensive fluorescence under the two-photon excitation. Changes of the optical density in the wavelength regions 250 ÷ 300 nm (DNA absorption) and 370 ÷ 650 nm (dye absorption) of DNA + dye solutions caused by the visible light irradiation are fixed. Bos-1 and DBos-30 dyes bound to DNA are more photostable than those in free state, being photochemically safe for DNA. DBos-24 and Dst-MdO dyes show a slight phototoxic effect on DNA.