Electrochemical Sensing of Chromium-Induced DNA Damage: DNA Strand Breakage by Intermediates of Chromium(VI) Electrochemical Reduction
Vacek, J., Mozga, T., Cahova, K., Pivonkova, H., Fojta, M.
ELECTROANALYSIS 19: 2093-2102 (2007)
DNA 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 M). 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 M 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.