A label-free electrochemical platform for the highly sensitive detection of hepatitis B virus DNA using graphene...

Based on the strong interaction between single-stranded DNA and graphene material, we have designed a simple but smart electrochemical platform to detect HBV-DNA by using a graphene quantum dot (GQD) modified glassy carbon electrode coupled with specific sequence DNA molecules as probes. The probe DNA is designed to be complementary to the HBV-DNA, when the probe DNA is strongly bound to the surface of the GQD modified electrode the transfer of an electron from the electrode to the electrochemically active species K₃[Fe(CN)₆] will become difficult. Nevertheless, if the target HBV-DNA is found in the test solution, the probe DNA will bind with the target HBV-DNA instead of GQDs. As a result, the obtained peak currents of K₃[Fe(CN)₆] will have a different degree of increase with the different concentrations of the target HBV-DNA. In particular, the proposed sensor exhibits high sensitivity with a detection limit of 1 nM, and the linear detection range is from 10 nM to 500 nM. Additionally, the sensor could be used in detecting other probe DNA, which may have potential applications in the future.