Synthesis, Characterization, and DNA Interaction Studies of Dysprosium(III) with Methylene Blue

The interaction between methylene blue-Dy(III) complex and herring sperm DNA was investigated in physiological buffer (pH 7.40). The binding ratios and the apparent molar absorptivity of (MB)-M-epsilon-Dy-DNA were determined by the molar ratio method. The thermodynamic parameters were calculated by a double-reciprocal equation at different temperatures, and showed that the interaction of methylene blue-Dy(III) complex with DNA was driven mainly by Delta S-r(m)Theta. By combination analysis of the Scatchard method, viscosity measurements, ferrocyanide quenching experiments, and circular dichroism spectroscopy, the methylene blue-Dy(III) complex can bind to DNA, and the major binding mode is electrostatic and partial intercalation binding.