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A composite film of DNA/poly(3-methylthiophene)(P3MT) modified glassy carbon electrode(GCE) has been fabricated by electro-deposition method.P3MT film was first electropolymerized at the GCE and the DNA layer was then immobilized on the P3MT layer by electrochemical method.The voltammetric behavior of 8-hydroxy-2’-deoxyguanosine(8-OH-dG) at the composite film modified electrode was studied.The effects of scan rates,pH and the interference of uric acid(UA) on the voltammetric behavior and detection of 8-OH-dG were also discussed.The experimental results suggest that the electrochemical behavior of 8-OH-dG at the composite film modified electrode was greatly improved due to the combination of the advantages of P3MT and DNA.In 0.1 M pH 7.0 phosphate buffer solution(PBS),the anodic peak currents of 8-OH-dG were linear with the 8-OH-dG concentration in two intervals,viz.0.28―4.2 μM and 4.2―19.6 μM.The detection limit of 56 nM 8-OH-dG could be estimated(S/N=3).This proposed composite film modified electrode shows excellent reproducibility and stability.It may have the potential application for the detection of 8-OH-dG in human urine.
A composite film of DNA / poly (3-methylthiophene) (P3MT) modified glassy carbon electrode (GCE) has been fabricated by electro-deposition method. P3MT film was first electropolymerized at the GCE and the DNA layer was then immobilized on the P3MT layer by electrochemical method. The voltammetric behavior of 8-hydroxy-2’-deoxyguanosine (8-OH-dG) at the composite film modified electrode was studied. effects of scan rates, pH and the interference of uric acid (UA) on the voltammetric behavior and detection of 8-OH-dG was also discussed. The experimental results suggest that the electrochemical behavior of 8-OH-dG at the composite film modified electrode was greatly improved due to the combination of the advantages of P3MT and DNA. 0.1 M pH 7.0 phosphate buffer solution (PBS), the anodic peak currents of 8-OH-dG were linear with the 8-OH-dG concentration in two intervals, viz.0.28-4.2 μM and 4.2-19.6 μM. The detection limit of 56 nM 8-OH-dG could be estimated (S / N = 3) .This proposed composite f ilm modified electrode shows excellent reproducibility and stability. It may have the potential application for the detection of 8-OH-dG in human urine.