SARS-CoV-2 detection using quantum dot fluorescence immunochromatography combined with isothermal amplification and CRISPR/Cas13a

The development of reliable, sensitive, and fast devices for the diagnosis of COVID-19 is of great importance in the pandemic of the new coronavirus. Here, we proposed a new principle of analysis based on a combination of reverse transcription and isothermal amplification of a fragment of the gene encoding the S protein of the SARS-CoV-2 and the CRISPR/Cas13a reaction for cleavage of the specific probe. As a result, the destroyed probe cannot be detected on an immunochromatographic strip using quantum fluorescent dots. Besides, the results can be obtained by an available and inexpensive portable device. By detecting SARS-CoV-2 negative (n = 25) and positive (n = 62) clinical samples including throat swabs, sputum and anal swabs, the assay showed good sensitivity and specificity of the method and could be completed within 1 h without complicated operation and expensive equipment. These superiorities showed its potential for fast point-of-care screening of SARS-CoV-2 during the outbreak, especially in remote and underdeveloped areas with limited equipment and resources.

Automated summary

The development of reliable and fast diagnostic devices for COVID-19 is crucial. In this study, a new analysis principle combining reverse transcription and isothermal amplification with CRISPR/Cas13a reaction was proposed. The method showed good sensitivity and specificity in detecting the SARS-CoV-2 gene fragment, and results could be obtained within 1 hour using a portable device. This approach has the potential for point-of-care screening in remote areas with limited resources.