由于微小RNA(miRNA)可以预测肿瘤发生，精确鉴定和定量高度相似序列的miRNA预计能够反映肿瘤的诊断和治疗。在本研究中，基于带有锁核酸(LNA)、氧化石墨烯基纳米复合物以富集发光体和导电基质的Y形结构的电化学发光(ECL)生物传感器被构建出来以用于miRNA的测定。具体来说，设计了两种LNA修饰的探针用于特异性miRNA识别，即双胺功能化的发夹捕获探针和信号探针。在电极表面通过miRNA在两个分支间杂交形成了一个Y形DNA结构，从而增强了选择性。以富集发光体碳量子点(CQDs)的聚乙烯亚胺-氧化石墨烯(PEI-GO)纳米复合物被开发出来，从而增强了ECL强度。作为间接信号放大，通过电化学活化的聚(2-氨基对苯二甲酸)ATA膜修饰金纳米颗粒被制备在电极上作为加速电子转移的有效基质。所构建的ECL生物传感器以极低的检测限制(1.95 fM，S/N = 3)实现了对miRNA-222的敏感检测。值得注意的是，配备了LNA探针的Y形结构使ECL生物传感器具有显著的单碱基鉴别能力和抗干扰能力。总的来说，所提出的Y形ECL生物传感器在临床生物标志物测定方面具有重要的应用前景。版权所有 © 2023 Elsevier B.V. 保留所有权利。

Since microRNAs (miRNAs) are predictors of tumorigenesis, accurate identification and quantification of miRNAs with highly similar sequences are expected to reflect tumor diagnosis and treatment. In this study, a highly selective and sensitive electrochemiluminescence (ECL) biosensor was constructed for miRNAs determination based on Y-shaped junction structure equipped with locked nucleic acids (LNA), graphene oxide-based nanocomposite to enrich luminophores, and conductive matrix. Specifically, two LNA-modified probes were designed for specific miRNA recognition, that is, a dual-amine functionalized hairpin capture probe and a signal probe. A Y-shaped DNA junction structure was generated on the electrode surface upon miRNA hybridizing across the two branches, so as to enhance the selectivity. Carbon quantum dots-polyethylene imine-graphene oxide (CQDs-PEI-GO) nanocomposites were developed to enrich luminophores CQDs, and thus enhancing the ECL intensity. For indirect signal amplification, an electrochemically activated poly(2-aminoterephthalic acid) (ATA) film decorated with gold nanoparticles was prepared on electrode as an effective matrix to accelerate the electron transfer. The fabricated ECL biosensor achieved sensitive determination of miRNA-222 with a limit-of-detection (LOD) as low as 1.95 fM (S/N = 3). Notably, Y-shaped junction structures equipped with LNA probes endowed ECL biosensor with salient single-base discrimination ability and anti-interference capacity. Overall, the proposed Y-shaped ECL biosensor has considerable promise for clinical biomarker determination.Copyright © 2023 Elsevier B.V. All rights reserved.