Spectroscopic and electrochemical approaches for the analysis of interaction between textile dye 231 and salmon sperm DNA

Abstract

DNA is one of the most critical targets of many artificial agents listed as carcinogens. Most of them irreversibly bind to the DNA inducing genome mutation; therefore, it is vital to study the nature of binding of these molecules to anticipate their toxicity. The interaction between textile dye reactive red 231 and salmon sperm double-strand DNA (ss-dsDNA) was investigated applying cyclic voltammetry (CV), differential pulse voltammetry (DPV) and ultraviolet-visible spectroscopy (UV/vis spectroscopy). The changes in the anodic current signals of dye were observed in the presence and absence of ss dsDNA at a glassy carbon electrode (GCE) using CV. The diffusion coefficient (D) was found to be 2.2× 10-7 and 9.5× 10-8 cm2s-1 from the CV data for the free dye and the dye-DNA complex, respectively. The electrochemical and UV/vis spectroscopy indicated a 1:1 complex formation of dye with DNA. The binding constant (kb) between the dye and DNA was calculated to be 5.4×105M-1 and 4.9×105M-1 in pH 4.0, using CV and UV/vis spectroscopy, respectively. The overall results suggest that dye binds to DNA through the combined effect of intercalation and electrostatic interaction. The damage of the DNA was also detected through the changes in the voltammetric behaviour of the dye.