Electrochemical performance and detection of 8-Hydroxy-2'-deoxyguanosine at single-stranded DNA functionalized graphene modified glassy carbon electrode.

8-Hydroxy-2'-deoxyguanosine (8-OH-dG) is the most abundant oxidative product of DNA and it is also considered to be a biomarker of oxidative DNA damage. In this work, a novel biosensor was fabricated by combining the biocompatibility of single-stranded DNA (ss-DNA) and the excellent conductivity of graphene nanosheets (GNs). The biosensor showed high electrocatalytic activity to the oxidation of 8-OH-dG. The sensitivities were 13.23 (±0.03)μA μM(-1), 5.827 (±0.008) μA μM(-1) and 3.086 (±0.005) μA μM(-1) in the concentration ranges of 0.0056-1.155 μM, 1.155-11.655 μM and 11.655-36.155 μM, respectively. The detection limit was 0.875 nM (S/N=3). Furthermore, the electrochemical behavior of 8-OH-dG was also investigated in detail in the presence of uric acid. And the results showed that uric acid had interference with the trace detection of 8-OH-dG. But it can be eliminated completely by uricase. The as-prepared ss-DNA/GNs/GCE will be promising for the detection of 8-OH-dG in real samples.