Graphene quantum dots-based platform for the fabrication of electrochemical biosensors

Abstract Based on the strong interaction between single-stranded DNA (ssDNA) and graphene material, we have designed a simple but smart platform in this work to fabricate electrochemical biosensors by using graphene quantum dots modified pyrolytic graphite electrode coupled with specific sequence ssDNA molecules as probes. Due to the excellent conductivity of graphene material, the modified electrode can exhibit very fine electrochemical response. Nevertheless, the probe ssDNA will inhibit the electron transfer between the electrochemical active species [Fe(CN) 6 ] 3-/4- and the electrode after the probe molecules are strongly bound to the surface of the modified electrode via their interaction with graphene. However, when the target molecules such as target ssDNA or target protein also exist in the test solution, the probe ssDNA will bind with the target instead of graphene if the sequence of the probe ssDNA is designed as complementary to the target DNA or as the aptamer of the target protein. As a result, the obtained peak currents of [Fe(CN) 6 ] 3-/4- will increase with the target molecules, thus various electrochemical biosensors can be easily developed with this proposed platform. The fabricated electrochemical biosensors may also have high sensitivity and selectivity, which may have potential applications in the future.