Electrochemical Sensing of Chromium‐Induced DNA Damage: DNA Strand Breakage by Intermediates of Chromium(VI) Electrochemical Reduction

Abstract

AbstractDNA damage by CrV and/or CrIV intermediates of CrVI electrochemical reduction was detected using a supercoiled DNA‐modified mercury electrode. A signal sensitive to formation of DNA strand breaks, AC voltammetric DNA peak 3, increased due to incubation of the DNA‐modified electrode in micromolar solutions of CrVI at potentials sufficiently negative for CrVI reduction. Damage to DNA in solutions containing CrVI and a chemical reductant (ascorbic acid, AA) was observed only at relatively high chromium concentrations (hundreds of μM). To eliminate interferences of excess CrVI in measurements of guanine electrochemical signals, a magnetoseparation double surface electrochemical technique was introduced. Using this approach, DNA damage in solution was detected for 50–250 μM CrVI upon addition of 1 mM AA. Our results suggest a more efficient DNA damage at the electrode surface due to continuous production of the reactive chromium species, compared to DNA exposure to chromium being reduced chemically in solution.