In this study, we present an enzyme-free fluorescence biosensor for the highly sensitive detection of miRNA-21, a crucial biomarker in clinical diagnosis. Our innovative approach combines catalytic hairpin assembly (CHA) and entropy-driven amplification into a cascade amplification strategy. MicroRNA initiates the catalytic hairpin assembly reaction, liberating the trigger region needed for the entropy-driven amplification reaction. This triggers a series of strand displacement reactions, resulting in the separation of the fluorescence resonance energy transfer pair and an amplified fluorescence signal from FAM. Our cascade amplification strategy achieves ultra-sensitive microRNA detection, with an impressive limit of detection (LOD) of 1.3 fM, approximately 100-fold lower than CHA alone. Additionally, we successfully applied this biosensor for microRNA quantification in human serum and cell lysates, demonstrating its practicality and potential for early diagnosis.

中文翻译：

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使用无酶级联放大生物传感器进行高灵敏度 miRNA-21 检测

在这项研究中，我们提出了一种无酶荧光生物传感器，用于高灵敏度检测 miRNA-21（临床诊断中的关键生物标志物）。我们的创新方法将催化发夹组装 (CHA) 和熵驱动放大结合到级联放大策略中。 MicroRNA 启动催化发夹组装反应，释放熵驱动的扩增反应所需的触发区域。这会触发一系列链置换反应，导致荧光共振能量转移对分离并放大 FAM 的荧光信号。我们的级联扩增策略实现了超灵敏的 microRNA 检测，检测限 (LOD) 高达 1.3 fM，比单独使用 CHA 低约 100 倍。此外，我们成功地将这种生物传感器应用于人血清和细胞裂解物中的 microRNA 定量，证明了其实用性和早期诊断的潜力。