Interactions of night blue with nucleic acids and determination of nucleic acids using resonance light scattering technique

The noncovalent interactions of night blue (NB) with several nucle acids in buffer medium of Britton-Robinson at pH 4.1 have been studied by spectroscopic methods. It is shown that the binding of NB with nucleic acids involves the J-aggregtion of NB molecules on the surface of nucleic acids. The aggregation was encouraged by polyanions nucleic acids, in which nucleic acids served for acting templates. In this connection, a new method of nucleic acids with sensitivity at nanogram level is proposed based on the measurement of enhanced resonance light scattering (RIS). The linear range of ctDNA, fsDNA and yRNA is 0.01-2.5, 0.03-2.5 and 0.04-1.0 mug/mL, respectively, and the corresponding detection limits (3sigma) are 9.4, 7.3 and 5.7 ng/mL at 2.5 x 10(-5) mol/L of NB. Synthetic and real samples were analyzed with satisfactory results.