A Cationic Cyanine as a Near-IR Fluorescent Probe for Determination of Nucleic Acids

A method with an cationic near-IR cyanine as a fluorescent probe was developed for the determination of nucleic acids.The near-IR cyanine shows the maximum excitation and emission wavelengths at 765 and 790 nm,respectively,in aqueous solution.The method is based on the fluorescence decrease of near-IR cyanine in the presence of nucleic acids.Under optimal conditions,the ratio value of fluorescence intensity in the absence and presence of nucleic acids was proportional to the concentration of nucleic acids over the range of 0 08～1 2μg/mL for CT DNA or SM DNA,and 0 1～1 6μg/mL for Yeast RNA.The detection limits were 30 ng/mL for CT DNA,25 ng/mL for SM DNA and 70 ng/mL for Yeast RNA.The relative standard deviation(n=6) were 2 1%for 500 ng/mL CT DNA level.