Nat Biomed Eng . Rapid detection of SARS-CoV-2 RNA in saliva via Cas13

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Nat Biomed Eng


. 2022 Aug 11.
doi: 10.1038/s41551-022-00917-y. Online ahead of print.
Rapid detection of SARS-CoV-2 RNA in saliva via Cas13


Sita S Chandrasekaran ^{# 1 2 3} , Shreeya Agrawal ^{# 1 2} , Alison Fanton ^{# 1 2 3} , Aditya R Jangid ^{# 1 2} , Bérénice Charrez ³ , Arturo M Escajeda ⁴ , Sungmin Son ¹ , Roger Mcintosh ⁴ , Huyen Tran ⁴ , Abdul Bhuiya ^{1 3} , María Díaz de León Derby ^{1 3} , Neil A Switz ⁵ , Maxim Armstrong ⁶ , Andrew R Harris ¹ , Noam Prywes ² , Maria Lukarska ^{2 7} , Scott B Biering ⁸ , Dylan C J Smock ^{2 7} , Amanda Mok ⁹ , Gavin J Knott ^{2 7 10} , Qi Dang ² , Erik Van Dis ⁷ , Eli Dugan ^{2 7} , Shin Kim ^{2 7} , Tina Y Liu ^{2 7} , IGI Testing Consortium; Erica A Moehle ² , Katherine Kogut ¹¹ , Brenda Eskenazi ¹¹ , Eva Harris ⁸ , Sarah A Stanley ^{7 12} , Liana F Lareau ^{1 2} , Ming X Tan ⁴ , Daniel A Fletcher ¹ , Jennifer A Doudna ^{13 14 15 16 17 18} , David F Savage ¹⁹ , Patrick D Hsu ^{20 21 22}



Collaborators, Affiliations

• PMID: 35953650
• DOI: 10.1038/s41551-022-00917-y

Abstract

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.