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.

提出了一种基于双链特异性核酸酶 (DSN) 辅助循环放大结合光沉积 Ag 增强 BiVO ₄光阳极的新型分体式和信号光电化学 (PEC) 生物传感器，用于灵敏检测 microRNA (miRNA) -155。当目标miRNA存在时，银纳米立方（AgNC）修饰的捕获DNA（cDNA）会与miRNA杂交，触发DSN辅助循环扩增，导致AgNCs的释放。释放的 AgNC 被酸解并光沉积在 BiVO ₄电极上。与BiVO _{4电极相比，在此获得的BiVO 4}电极可以实现增强的光电流。/Ag 电极。并且首次观察到Ag光沉积后形态从蠕虫状纳米颗粒到纳米片的变化。这种PEC信号增强主要是由于Ag的局域表面等离子共振(LSPR)效应、BiVO ₄与Ag之间形成肖特基结以及形成具有更大比表面积的BiVO _{4纳米片的协同作用。}PEC信号增强与miRNA-155浓度呈正相关，因此该方法可用于灵敏、选择性地检测miRNA-155。可以达到上午 8 点的检测限。该策略不需要对电极逐层修改，操作简单，稳定性好。