Impedimetric DNA-biosensor for the study of dopamine induces DNA damage and investigation of inhibitory and repair effects of some antioxidants

• A DNA–biosensor was introduced to study DNA damage using impedance spectroscopy.
• Dopamine, Cu(II) and/or Fe(III) alone could not destroy DNA.
• Dopamine plus Cu(II) and/or dopamine plus Fe(III) can damage DNA.
• The damage ability of Cu(II)–dopamine was greater than Fe(III)–dopamine.
• The ability of glutathione is more than ascorbic acid (twice) to repair DNA damage.

A simple and inexpensive methodology was used to develop a new method in order to inspect the DNA damage due to dopamine and some ionic metals. In addition, the inhibitory and repair effects of some antioxidant such as glutathione and ascorbic acid were studied and compared with each other using electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). In this work a pencil graphite electrode (PGE) was modified with multiwall carbon nanotubes (MWCNTs) and chitosan (CHIT), then it was decorated with a ds-DNA (ds-DNA/CHIT–MWCNTs/PGE). Due to interaction of ds-DNA and the damaging agents (dopamine + metallic ions), electrochemical and spectroscopy properties of ds-DNA at the surface of the modified electrode was changed, and these changes are followed with EIS and DPV methods. Our study showed that dopamine, Cu(II) and Fe(III) alone could not destroy DNA, but dopamine + Cu(II) and dopamine + Fe(III) can damage DNA. In addition, the ability of dopamine–Cu(II) was greater than dopamine–Fe(III). Moreover, some antioxidant such as glutathione and ascorbic acid can overcome and/or minimize the influence of these damaging interactions.