A novel split-type photoelectrochemical biosensor based on double-strand specific nuclease-assisted cycle amplification coupled with plasmonic Ag enhanced BiVO4 performance for sensitive detection of microRNA-155

A novel split-type and signal-on photoelectrochemical (PEC) biosensor was proposed based on double-strand specific nuclease (DSN)-assisted recycling amplification coupled with photodeposited Ag enhanced BiVO4 photoanode for sensitive detection of microRNA (miRNA)− 155. In the presence of target miRNA, the capture DNA (cDNA) modified with silver nanocube(AgNC)would hybridize with the miRNA, then DSN-assisted cycle amplification was triggered, leading to the release of AgNCs. The released AgNCs were acidolyzed and photodeposited on the BiVO4 electrode. Compared with the BiVO4 electrode, an enhanced photocurrent could be achieved at this obtained BiVO4/Ag electrode. And the morphology change from worm-like nanoparticles to nanosheets after Ag photodeposition was observed for the first time. This PEC signal enhancement was mainly contributed to the synergistic action of localized surface plasmon resonance (LSPR) effect of Ag, Schottky junction formed between BiVO4 and Ag, and the formation of BiVO4 nanosheets with larger specific surface area. The PEC signal enhancement was positively related to the miRNA-155 concentration, so this method could be used to sensitively and selectively detect miRNA-155. A limit of detection of 8 aM could be achieved. This strategy does not require layer-by-layer modification of the electrode, so it is easy to operate, and owns good stability.