Analytical Sciences

Electrochemical and Spectroscopic Investigations of Protonated Ferrocene-DNA Intercalation

Afzal SHAH,* Rumana QURESHI,* Naveed Kausar JANJUA,* Sayedul HAQUE,** and Safeer AHMAD*

*Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad, Pakistan
**Department of Animal Sciences, Quaid-i-Azam University, 45320 Islamabad, Pakistan

The interaction of protonated ferrocene (PF) with chicken blood DNA (CB-DNA) has been investigated in vitro by cyclic voltammetry (CV) and UV-Vis spectroscopy as well as viscosity measurements under stomach pH and body temperature. The peak potentials shift in CV, hyperchromism in UV absorption titration, an increase in the viscosity of DNA and the results of the effect of ionic strength on the binding constant strongly support the intercalation of PF into the DNA double helix. The diffusion coefficients of PF in the presence and absence of DNA were 9.54 × 10^-11 and 1.34 × 10^-10 m²/s, respectively. The binding constant of the PF-DNA complex and the number of binding sites on a DNA molecule were calculated as being 3.07 × 10² M^-1 and 2.96, with the help of the Scatchard equation. An expression by Carter et al. was used for determining the binding site size (0.17 bp). The binding constant was also determined by UV absorption titration.

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