A sensitive electrochemical genosensor for measuring gastric cancer biomarker, microRNA-106b, based on asparagine polymerization on carbon quantum dots modified electrode

The aim of this work is to develop an electrochemical genosensor to measure microRNA 106b (miR-106b) as a gastric cancer biomarker. To construct the miR-106b genosensor, asparagine (As) was electropolymerized on the surface of carbon quantum dots modified glassy carbon electrode (CQDs/GCE). In the next step, ssDNA was immobilized on the modified electrode surface (As/CQDs/GCE) and then hybridized with miR-106b. Finally, differential pulse voltammograms of the accumulated chlorogenic acid (CGA), as an electroactive label, on the surface of immobilized ssDNA was recorded before (ssDNA/As/CQDs/GCE) and after hybridization with miR-106b (miR-106b/BSA/ssDNA/As/CQDs/GCE). The difference in the peak current of these two voltammograms was used as an analytical signal to measure of miR-106b. Using this genosensor, a linear concentration range from 1.0 fM to 1.0 µM and a detection limit of 0.39 fM were obtained for the measurement of miR-106b. The obtained data indicate that it is possible to recognize miR-106 from a non-complementary and a single-base mismatch sequence using the genosensor. In addition, the measurement of miR-106b in a human serum sample was successfully performed using the genosensor.