近年来，已经开发出多种技术来准确、灵敏地检测肿瘤生物标志物，以实现癌症的早期诊断和有效治疗。电化学发光（ECL）方法具有灵敏度高、操作简便、时空可控等突出特点，在DNA/RNA检测、免疫分析、癌细胞检测和环境分析等方面展现出巨大的潜力。然而，ECL方法的一个突出问题是电极上的逐层修饰导致传感器的稳定性和灵敏度较差。因此，能够有效改善ECL信号的简单高效的电极修饰新方法引起了越来越多的研究兴趣。基于靶诱导CHA和纳米复合探针导致自生成共反应物（H2O2）的双重放大策略，我们提出了一种高灵敏度的miRNA-ECL检测系统。目标miRNA-21的引入触发DNA1和生物素修饰的DNA2的CHA循环扩增，释放目标miRNA-21序列用于目标循环反应。反应后，新引入的DNA2与用SA和葡萄糖氧化酶（GOD）修饰的Au NPs结合。在氧气存在下，葡萄糖被GOD分解产生H2O2，然后H2O2立即被CHA产物双链末端的Hemin/G-四联体催化，产生大量的O2-·。作为鲁米诺的共反应物，ECL信号显着增强，从而实现miRNA-21含量的高灵敏检测，并获得0.65 fM的低检测限。通过碱基错配也证明了ECL生物传感器的高特异性。与目前其他检测方法相比，该传感器可以通过灵活改变探针DNA序列实现其他目标分析物的定量分析，为肿瘤的检测提供了新的可行解决方案-相关标记。得益于灵敏度和选择性的提高，所提出的生物传感平台有望为生物标志物分析提供新的策略，并为进一步的临床应用提供良好的前景。版权所有 © 2024 Elsevier B.V. 保留所有权利。

Recently, various techniques have been developed to accurately and sensitively detect tumor biomarkers for the early diagnosis and effective therapy of cancer. The electrochemiluminescence (ECL) method holding outstanding features including high sensitivity, ease of operation, and spatiotemporal controllability exhibited great potential for DNA/RNA detection, immunoassay, cancer cell detection, and environmental analysis. However, a glaring problem of ECL approaches is that the layer-by-layer modification on the electrode leads to poor stability and sensitivity of the sensors. Therefore, new simple and efficient methods for electrode modification which can effectively improve the ECL signal have attracted more and more research interests.Based on the dual amplification strategy of target-induced CHA and nanocomposite probes leading to self-generated co-reactant (H2O2), we proposed a highly sensitive miRNA-ECL detection system. The introduction of the target miRNA-21 triggers the CHA cycle amplification of DNA1 and biotin-modified DNA2, releasing the target miRNA-21 sequence for the target cycle reaction. After the reaction, the newly introduced DNA2 was combined with Au NPs modified with SA and Glucose oxidase (GOD). In the presence of oxygen, glucose was decomposed by GOD to produce H2O2, and then H2O2 was immediately catalyzed by the Hemin/G-quadruplex at the double-stranded end of the CHA product to produce a large amount of O2-•. As a co-reactant of luminol, the ECL signal was significantly enhanced, thereby achieving highly sensitive detection of miRNA-21 content and obtaining a low detection limit of 0.65 fM. The high specificity of the ECL biosensor was also proved by base mismatch.Compared with other current detection methods, this sensor can achieve quantitative analysis of other target analytes by flexibly changing the probe DNA sequence, and provide a new feasible solution for the detection of tumor-associated markers. Benefiting from the improved sensitivity and selectivity, the proposed biosensing platform is expected to provide a new strategy for biomarkers analysis and outstanding prospect for further clinical application.Copyright © 2024 Elsevier B.V. All rights reserved.