The aberrant expression of microRNA (miRNA) is closely associated with various pathological processes, such as the development of gastric cancer. High-efficiency quantification of miRNAs is significant for the diagnosis, prognosis, and treatment of cancers. However, the sensitive and reliable detection of miRNA remains a huge challenge. We depict here a novel fluorescent approach for sensitive and label-free miRNA detection by exploiting a designed detection scaffold to integrate the catalytic hairpin assembly and primer exchange reaction (PER). In this method, the detection scaffold that is constructed based on the hybridization between two hairpin structure probes (H1 probe and H2 probe), is capable of specifically recognizing target miRNA and activating signal amplification, and the PER process transcribes numerous G-rich sequences to induce ThT-based label-free signal generation. Based on the efficient signal amplification strategy and label-free signal generation mode, the method exhibits a wide detection range of 7 orders of magnitude and a high repeatability (coefficient of variation, 2.76%), implying that the proposed approach will be a robust tool in quantification of miRNA and early diagnosis of disease.

中文翻译：

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双发夹组装探针介导催化发夹组装和引物交换反应，用于胃癌中灵敏且无标记的 miRNA 分析

microRNA（miRNA）的异常表达与多种病理过程密切相关，例如胃癌的发生发展。miRNA 的高效定量对于癌症的诊断、预后和治疗具有重要意义。然而，灵敏、可靠的 miRNA 检测仍然是一个巨大的挑战。我们在这里描述了一种新颖的荧光方法，通过利用设计的检测支架来整合催化发夹组装和引物交换反应（PER），用于灵敏且无标记的 miRNA 检测。该方法中，基于两个发夹结构探针（H1探针和H2探针）杂交构建的检测支架能够特异性识别目标miRNA并激活信号放大，PER 过程转录大量富含 G 的序列以诱导基于 ThT 的无标记信号生成。基于高效的信号放大策略和无标记信号生成模式，该方法表现出7个数量级的宽检测范围和高重复性（变异系数，2.76％），这意味着该方法将是一个强大的工具miRNA 定量和疾病早期诊断。