Electrochemical Inspection of the Interaction of Double Strand ds-DNA with Carmine on Nanometer TiO₂ Doped Carbon Paste Electrode

Abstract

The interaction of the single azo dye, carmine with fish-sperm dsDNA is inspected in pH 3.2 H2SO4with electrochemical method on the surface of nanometer TiO2modified carbon paste electrode. After the addition of dsDNA, the peak currents of oxidation and reduction peaks of carmine decrease with a positive shift of potential, indicating that intercalation interaction between the dye and dsDNA is taken place. This is consistent with fluorescence spectra results. The binding constant and binding ratio is calculated as 4.92×108and 1:2, respectively. Furthermore, the decrease in the oxidation peak currents is found proportional to dsDNA concentration in the range of 21.24-127.44 μg·mL-1 with a detection limit of 16.04 μg•mL-1.