Rapid detection of SARS-CoV-2 RNA in saliva via Cas13
Nature Biomedical Engineering
Rapid nucleic acid testing is central to infectious disease surveillance. Here, we report an assay for rapid COVID-19 testing and its implementation in a prototype microfluidic device. The assay, which we named DISCoVER (for diagnostics with coronavirus enzymatic reporting), involves extraction-free sample lysis via shelf-stable and low-cost reagents, multiplexed isothermal RNA amplification followed by T7 transcription, and Cas13-mediated cleavage of a quenched fluorophore. The device consists of a single-use gravity-driven microfluidic cartridge inserted into a compact instrument for automated running of the assay and readout of fluorescence within 60 min. DISCoVER can detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in saliva with a sensitivity of 40 copies μl–1, and was 94% sensitive and 100% specific when validated (against quantitative PCR) using total RNA extracted from 63 nasal-swab samples (33 SARS-CoV-2-positive, with cycle-threshold values of 13–35). The device correctly identified all tested clinical saliva samples (10 SARS-CoV-2-positive out of 13, with cycle-threshold values of 23–31). Rapid point-of-care nucleic acid testing may broaden the use of molecular diagnostics.
National Science Foundation
Physics and Astronomy
Sita S. Chandrasekaran; Shreeya Agrawal; Alison Fanton; Aditya R. Jangid; Bérénice Charrez; Arturo M. Escajeda; Sungmin Son; Roger Mcintosh; Huyen Tran; Abdul Bhuiya; María Díaz de León Derby; Neil A. Switz; Maxim Armstrong; Andrew R. Harris; Noam Prywes; Maria Lukarska; Scott B. Biering; Dylan C.J. Smock; and For full author list, see comments below. "Rapid detection of SARS-CoV-2 RNA in saliva via Cas13" Nature Biomedical Engineering (2022): 944-956. https://doi.org/10.1038/s41551-022-00917-y