Abstract：
MicroRNA detection is crucial for early infectious disease diagnosis and rapid cancer screening. However, conventional techniques like reverse transcription-quantitative polymerase chain reaction, requiring specialized training and intricate procedures, are less suitable for point-of-care analyses. To address this, we\'ve developed a straightforward amplifier based on an exonuclease III (exo III)-propelled DNAzyme walker for sensitive and selective microRNA detection. This amplifier employs a specially designed hairpin probe with two exposed segments for strand recognition. Once the target microRNA is identified by the hairpin\'s extended single-strand DNA, exo III initiates its digestion, allowing microRNA regeneration and subsequent hairpin probe digestion cycles. This cyclical process produces a significant amount of DNAzyme, leading to a marked reduction in electrochemical signals. The biosensor exhibits a detection range from 10 fM to 100 pM and achieves a detection limit of 5 fM (3σ criterion). Importantly, by integrating an \"And logic gate,\" our system gains the capacity for simultaneous diagnosis of multiple microRNAs, enhancing its applicability in RNA-based disease diagnostics.
摘要：
MicroRNA检测对于早期感染性疾病诊断和癌症快速筛查至关重要。然而,常规技术，如逆转录定量聚合酶链反应，需要专门的培训和复杂的程序，不太适合即时分析。为了解决这个问题，我们已经开发了一种基于外切核酸酶III（exoIII）推进的DNA酶步行器的直接放大器，用于灵敏和选择性的microRNA检测。该放大器采用特殊设计的发夹探针,其具有两个暴露的片段用于链识别。一旦通过发夹延伸的单链DNA鉴定了目标microRNA，exoIII启动它的消化，允许microRNA再生和随后的发夹探针消化循环。这个循环过程产生大量的DNA酶，导致电化学信号显著减少。生物传感器表现出从10fM到100pM的检测范围,并实现5fM(3σ标准)的检测极限。重要的是,通过集成一个\"和逻辑门，“我们的系统获得了同时诊断多种microRNA的能力，增强其在基于RNA的疾病诊断中的适用性。
