RAPID: Enzyme-free detection of coronavirus RNA using reconfigurable DNA nanoswitches

控制当前新冠肺炎疫情的一个关键方面是及早和快速检测感染人群。目前检测导致新冠肺炎的新型冠状病毒的方法通常需要实验室，并使用昂贵的设备和试剂。这些要求限制了可以在全国范围内进行的测试数量。在这个项目中，研究小组的目标是开发一种替代诊断方法，直接检测病毒RNA，而不需要任何扩增、标记或使用酶。该分析只需最少的步骤，并使用一种紧凑、无缓冲的凝胶盒系统，可以在临床环境中部署。除了目前的新冠肺炎疫情，这个传感平台也可以应用于其他现有的或新兴的病毒。这项工作旨在开发一种足够灵敏的纳米开关检测方法，能够在1小时内检测到临床水平的SARS-CoV-2病毒RNA。一旦从样本中提取了病毒RNA，RNA就会被碎片化，并与基于DNA的纳米开关混合。将特定序列的病毒RNA片段与纳米开关杂交后，工程DNA链的构象将从线性的“关”状态转变为环状的“开”状态。在凝胶盒系统中通过电泳法将靶结合的环状形式与线性纳米开关分离后，根据凝胶图像中环状(开)纳米开关的强度来量化病毒载量。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A critical aspect of controlling the current COVID-19 outbreaks is early and fast detection of the infected population. Current methods for detecting the novel coronavirus that causes COVID-19 typically require a laboratory and use expensive equipment and reagents. These requirements limit the number of tests that can be performed nationwide. In this project, the research team aims to develop an alternative diagnostic approach that directly detects the viral RNA without any amplification, labeling, or the use of enzymes. The assay requires minimal steps and uses a compact, bufferless gel cartridge system that can be deployed in a clinical setting. Beyond the current COVID-19 outbreak, this sensing platform can also apply to other existing or emerging viruses.This work aims to develop a nanoswitch assay sensitive enough to detect clinical levels of SARS-CoV-2 viral RNA within 1 hour. Once the viral RNA is extracted from a sample, the RNA is fragmented and mixed with the DNA-based nanoswitches. Hybridization of a viral RNA fragment of a specific sequence with a nanoswitch induces a conformational change of the engineered DNA strand from its linear "off" state to a looped "on" state. After separation of the target-bound looped form from the linear nanoswitches by electrophoresis in a gel cartridge system, the viral load is quantified from the intensity of the looped (on) nanoswitches in a gel image.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.