In the last three decades, there have been recurring outbreaks of infectious diseases, brought to light with the recent outbreak of coronavirus disease 2019 (COVID-19). Attempts to effectively contain the spread of infectious diseases have been hampered by the lack of rapidly adaptable, accurate, and accessible point-of-care diagnostic testing. In this study, we present a novel design of a label-free DNAzyme-based detection method called Rapidemic. This assay combines recombinase polymerase amplification (RPA) with linear strand-displacement amplification (LSDA) and guanine-quadruplex (GQ) DNAzyme-catalysed colour-changing reaction. The colorimetry basis of the signal readout omits the need for extensive instrumentation. Moreover, the primer-based sequence detection of RPA gives Rapidemic a potential to be rapidly adapted to target a new sequence. As a proof of concept, we developed the assay to detect isolated genomic DNA of Saccharomyces cerevisiae. The use of low-pH buffers and the optimization of the dilution rates from each preceding reaction to the next showed to be successful strategies to enable visible detection with this method. These findings demonstrate for the first time that a label-free DNAzyme-based detection method can be coupled to RPA and LSDA for nucleic acid detection.

中文翻译：

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Rapidemic，一种基于多功能酶且无标签的基于DNA酶的平台，用于视觉核酸检测

在过去的三十年中，随着最近的2019年冠状病毒疾病（COVID-19）爆发，传染病再次爆发。由于缺乏快速适应性强，准确性高且易于使用的即时诊断服务，阻碍了有效控制传染病传播的尝试。在这项研究中，我们提出了一种新的设计，称为Rapidemic的无标签基于DNA酶的检测方法。该测定法将重组酶聚合酶扩增（RPA）与线性链置换扩增（LSDA）和鸟嘌呤四联体（GQ）DNAzyme催化的变色反应结合在一起。信号读数的比色法基础不需要广泛的仪器。此外，RPA的基于引物的序列检测为Rapidemic提供了迅速适应新序列的潜力。作为概念的证明，我们开发了用于检测酿酒酵母分离基因组DNA的检测方法。使用低pH缓冲液以及优化从每个先前反应到下一个反应的稀释率是成功的策略，可以使用此方法进行可见检测。这些发现首次证明了无标记的基于DNAzyme的检测方法可以与RPA和LSDA结合用于核酸检测。