miRNA-21被认为是乳腺癌诊断、治疗和预后的重要生物标志物。在这里，我们创建了一种纳米通道生物传感器，利用双链体特异性核酸酶（DSN）信号放大策略来实现 miRNA 的检测。在该系统中，DNA作为捕获探针共价固定在纳米通道表面，与目标miRNA杂交并形成RNA/DNA双链体。 DSN 可以切割 RNA/DNA 双链体中的探针 DNA，回收目标 miRNA，从而可以再次与其他 DNA 探针杂交。 N次循环后，大部分DNA探针被裂解，通过检测表面电荷密度的变化可以定量miRNA的含量。该生物传感器可以区分 miR-21 与非互补 miRNA 和一碱基错配 miRNA，在 PBS 中可靠的检测限低至 1 fM。此外，我们还成功将该方法应用于MCF-7细胞和HeLa细胞中总RNA样品的分析，并且纳米通道也表现出了优异的响应能力和较强的抗干扰能力。这种新方法有望为临床诊断中的 miRNA 检测做出贡献，提供一种独特的方法来检测和区分疾病相关分子。版权所有 © 2024 Elsevier B.V. 保留所有权利。

MiRNA-21 is recognized as an important biological marker for the diagnosis, treatment, and prognosis of breast cancer. Here, we have created a nanochannel biosensor utilizing the duplex-specific nuclease (DSN) signal amplification strategy to achieve the detection of miRNAs. In this system, DNA as the capture probe was covalently immobilized on the surface of nanochannels, which hybridized with the target miRNA and forms RNA/DNA duplexes. DSN could cleave the probe DNA in RNA/DNA duplexes, recycling target miRNA, which may again hybridized with other DNA probes. After N cycles, most of the DNA probes had been cleaved, and the content of miRNA could be quantified by detecting changes in surface charge density. This biosensor can distinguish miR-21 from non-complementary miRNAs and one-base mismatched miRNAs, with reliable detection limits as low as 1 fM in PBS. In addition, we had successfully applied this method to analysis of total RNA samples in MCF-7 cells and HeLa cells, and the nanochannels had also shown excellent responsiveness and strong anti-interference ability. This new method is expected to contribute to miRNA detection in clinical diagnostics, providing a unique approach to detecting and distinguishing disease-associated molecules.Copyright © 2024 Elsevier B.V. All rights reserved.