Photophysics of DNA staining dye Propidium Iodide encapsulated in bio-mimetic micelle and genomic fish sperm DNA

摘要

Photophysical processes in Propidium Iodide (PI), the well known DNA staining dye, have been exploited in homogeneous as well as heterogeneous medium by steady state and time resolved spectroscopy. The DNA staining dye PI exhibits intermolecular proton transfer reaction in aqueous and hydrogen-bonding acceptor solvents due to the formation of quinonoid structure which is acidic in nature. Time resolved emission spectroscopy also predicts the hydrogen bond donor ability of PI. The target dye interacts only with anionic surfactant sodium dodecylsulphate but not with cationic surfactant cetyltrimethylammo-nium bromide and neutral surfactant Triton X-100 and this interaction is found to be electrostatic in nature. We have further scrutinized the mode of binding of PI with fish sperm DNA. The effect of addition of urea, fluorescence quenching phenomenon, CD measurements reveal that the probe binds to DNA through intercalative style.