A sensitive electrochemical DNA biosensor based on gold nanomaterial and graphene amplified signal

• An electrochemical DNA biosensor was fabricated based on sandwich sensing strategy.
• Au NRs was incorporated in the design of electrochemical sensing platform.
• The Au NRs decorated rGO can be obtained by electrostatic self-assemble methods.
• The DNA biosensor shows excellent sensitivity with a detection limit of 3.5 × 10−17 M.

In this study, we developed a highly sensitive and selective electrochemical biosensor for the detection of the specific-sequence target DNA. It was fabricated based on a “sandwich-type” detection strategy, which involved capture probe immobilized on the surface of the gold nanorods (Au NRs) decorated reduced graphene oxide (rGO) sheets, and reporter probe labeled gold nanoparticle (Au NPs) that flank the target DNA. Adriamycin was used as an electrochemical indicator because it could be electrostatically bonded to the anionic phosphate of DNA strands. Differential pulse voltammetry (DPV) was used to investigate the hybridization event by the measurements of peak current of adriamycin changed before and after hybridization. The incorporation of Au NPs and Au NRs decorated rGO sheets in this sensor design significantly enhanced the sensing performance. Under optimal conditions, the peak currents of adriamycin in DPV were linear with the logarithm of target DNA concentration in the range of 1.0 × 10−16 to 1.0 × 10−9 M with a detection limit of 3.5 × 10−17 M (signal/noise ratio of 3). In addition, this DNA sensor exhibited good selectivity, even for single-base mismatched target DNA detection.

In this study, we developed a highly sensitive and selective electrochemical biosensor for the detection of the specific-sequence target DNA. We employed electrostatic self-assemble method for preparing Au NRs–rGO conjugates for capture probe immobilization, and reporter probe capped with Au NPs conjugates were used to fabricate “sandwich-type” DNA biosensor. Adriamycin was used as electrochemical indicator. Differential pulse voltammetry was used to investigate the hybridization event by the measurements of peak current of adriamycin changed. The peak currents of adriamycin were linear with the logarithm of target DNA concentration in the range of 1.0 × 10−16 to 1.0 × 10−9 M, with a detection limit of 3.5 × 10−17 M (signal/noise ratio of 3). In addition, this DNA sensor exhibited good selectivity, reproducibility and stability.Figure optionsDownload as PowerPoint slide