Amplification-free detection of SARS-CoV-2 with CRISPR-Cas13a and mobile phone microscopyParinaz Fozouni , Sungmin Son, María Díaz de León Derb , Gavin J Knott , Carley N Gray, Michael V D'Ambrosio , Chunyu Zhao , Neil A Switz , G Renuka Kumar, Stephanie I Stephens , Daniela Boehm , Chia-Lin Tsou, Jeffrey Shu, Abdul Bhuiya, Maxim Armstrong , Andrew R Harris , Pei-Yi Chen , Jeannette M Osterloh, Anke Meyer-Franke, Bastian Joehnk , Keith Walcott, Anita Sil , Charles Langelier, Katherine S Pollard , Emily D Crawford , Andreas S Puschnik , Maira Phelps, Amy Kistler , Joseph L DeRisi , Jennifer A Doudna , Daniel A Fletcher, Melanie Ott
Cell 2021Abstract: The December 2019 outbreak of a novel respiratory virus, SARS-CoV-2, has become an ongoing global pandemic due in part to the challenge of identifying symptomatic, asymptomatic, and pre-symptomatic carriers of the virus. CRISPR diagnostics can augment gold-standard PCR-based testing if they can be made rapid, portable, and accurate. Here, we report the development of an amplification-free CRISPR-Cas13a assay for direct detection of SARS-CoV-2 from nasal swab RNA that can be read with a mobile phone microscope. The assay achieved ∼100 copies/μL sensitivity in under 30 min of measurement time and accurately detected pre-extracted RNA from a set of positive clinical samples in under 5 min. We combined crRNAs targeting SARS-CoV-2 RNA to improve sensitivity and specificity and directly quantified viral load using enzyme kinetics. Integrated with a reader device based on a mobile phone, this assay has the potential to enable rapid, low-cost, point-of-care screening for SARS-CoV-2.
