Label-free and reagentless electrochemical detection of microRNAs using a conducting polymer nanostructured by carbon nanotubes: Application to prostate cancer biomarker miR-141

In this paper, a label-free and reagentless microRNA sensor based on an interpenetrated network of carbon nanotubes and electroactive polymer is described. The nanostructured polymer film presents very well-defined electroactivity in neutral aqueous medium in the cathodic potential domain from the quinone group embedded in the polymer backbone. Addition of microRNA miR-141 target (prostate cancer biomarker) gives a “signal-on” response, i.e. a current increase due to enhancement of the polymer electroactivity. On the contrary, non-complementary miRNAs such as miR-103 and miR-29b-1 do not lead to any significant current change. A very low detection limit of ca. 8fM is achieved with this sensor. [Display omitted] •MicroRNA detection.•Label-free and direct electrochemical detection.•Conducting polymer nanostructured by carbon nanotubes.•Prostate cancer biomarker miR-141.