Electrochemical performance of 8-hydroxy-2 '-deoxyguanosine and its detection at poly(3-methylthiophene) modified glassy carbon electrode

摘要

8-Hydroxy-2'-deoxyguanosine (8-OH-dG) has attracted enormous attention in recent years because it has been acknowledged as a typical biomarker of oxidative DNA damage. In this paper, the electrochemical performance of 8-OH-dG at the poly(3-methylthiophene) (P3MT) modified glassy carbon electrode (GCE) was investigated by cyclic voltarnmetry (CV) and linear sweep voltarnmetry (LSV). The conducting polymer P3MT can effectively decrease the oxidation peak potential of 8-OH-dG and greatly enhance its peak current. In 0.1 M pH 7.0 phosphate buffer solution (PBS), the anodic peak currents of cyclic voltammograms are linear with the 8-OH-dG concentration in two intervals, viz. 0.700-35.0 mu M and 35.0-70.0 mu M, with the correlative coefficients of 0.9992 and 0.9995, respectively. The detection limit of 8-OH-dG can be estimated to be 0. 100 mu M (S/N = 3). This modified electrode can be used to detect the amount of 8-OH-dG in human urine. Furthermore, the effects of scan rate, pH, and interference of uric acid (UA) for the voltarnmetric behavior and detection of 8-OH-dG are also discussed. This proposed modified electrode also shows excellent reproducibility and stability that makes it an ideal candidate for amperometric detection of 8-OH-dG in flow injection analysis (FIA) and high performance liquid chromatography (HPLC). (c) 2006 Elsevier B.V. All rights reserved.