In this work, an electrochemical biosensor based on Au nanorods (NRs) modified microfluidic paper-based analytical devices (μPADs) were constructed for sensitive detection of microRNA (miRNA) by using cerium dioxide - [email protected] oxidase (CeO₂[email protected]) as an electrochemical probe for signal amplification. Au NRs were synthesized by in-situ growth method in μPADs surface to enhance the conductivity and modified hairpin probe through Au-S bonds. The construction of “the signal transducer layer” was carried out by GOx catalyzing glucose to produce H₂O₂, which was further electrocatalyzed by CeO₂. After the biosensor was constructed, an obvious electrochemical signal was observed from the reduction of H₂O₂. In order to make the detection more convincing, the visual detection was performed based on the oxidation of 3,3′,5,5′-tetramethylbenzidine by H₂O₂ with the help of Exonuclease I. The electrochemical biosensor provided a wide linear range of 1.0 fM to 1000 fM with a relatively low detection limit of 0.434 fM by the electrochemical measurement. Linear range of 10 fM to 1000 fM with a relatively low detection limit of 7.382 fM was obtained by visual detection. The results indicated the proposed platform has potential utility for detection of miRNA.

在这项工作中，构建了基于金纳米棒（NRs）修饰的基于微流体纸质分析设备（μPADs）的电化学生物传感器，用于通过使用二氧化铈-[受电子邮件保护的]氧化酶（CeO ₂ [受电子邮件保护的）敏感地检测microRNA（miRNA）。]）作为信号放大的电化学探针。通过原位生长法在μPADs表面合成Au NR，以增强电导率，并通过Au-S键修饰发夹探针。通过GOx催化葡萄糖产生H ₂ O ₂进行“信号换能器层”的构建，然后通过CeO ₂对其进行电催化。构建生物传感器后，从H ₂的还原中观察到明显的电化学信号O ₂。为了使检测更具说服力，在核酸外切酶I的帮助下，基于H ₂ O ₂对3,3'，5,5'-四甲基联苯胺的氧化进行了视觉检测。电化学生物传感器提供了宽线性范围通过电化学测量，其检测限为1.0 fM至1000 fM，相对较低的检测极限为0.434 fM。通过视觉检测获得了10 fM至1000 fM的线性范围，具有7.382 fM的相对较低的检测极限。结果表明，所提出的平台具有检测miRNA的潜在实用性。