An organic electrochemical transistor for determination of microRNA21 using gold nanoparticles and a capture DNA probe.

A method is described for the determination of microRNA. It is based on the use of organic electrochemical transistors (OECTs) fabricated on a flexible poly(ethylene terephthalate) substrate. A gold electrode was modified with gold nanoparticles to immobilize the capture DNA probe and then served as the gate of the device. The detection of microRNA21 was realized by monitoring the change of the drain-source current after hybridization of capture DNA with microRNA21. Under optimal conditions, this biosensor exhibits good sensitivity and specificity. It works in the 5 pM to 20 nM microRNA concentration range and has a 2 pM detection limit. Graphical abstract Schematic of the organic electrochemical transistor-based microRNA21 biosensor. It constitutes a screen-printed carbon source (S) and drain (D) electrodes, a spin-coated poly(3,4-ethylenedioxythiophere):poly(styrene sulfonic acid) (PEDOT:PSS) film on the poly(ethylene terephthalate) (PET) substrate, and a gold gate modified with gold nanoparticles (Au NPs), capture probe, and 6-mercapto-1-hexanol (MCH).