Fig. 1

An OR-DETECTR platform for detection of SARS-CoV-2. a Schematic of OR-DETECTR testing SARS-CoV-2 workflow. RNA extraction from pharyngeal swab can be used as an input to OR-DETECTR (One-tube detection platform combined RT-RPA based preamplification and CRISPR/Cas12a based DETECTR), which is visualized by a fluorescent reader. The RT-RPA mix is located at the bottom of the centrifuge tube, while the DETECTR mix is located in the transparent tube lid. b Genome map showing primers and crRNAs. RT-RPA primers are indicated by black arrows which partially overlap with rRT-PCR primers of RdRp gene (WHO) or N gene (China CDC). Two crRNAs are indicated by light blue curves. c, d crRNA specificity. The crRNA targeting RdRp gene is designed to detect SARS-CoV-2 and SARS-CoV, which cause severe respiratory infection presented as fever, cough and dyspnea. e, f The crRNA targeting N gene was specific for SARS-CoV-2. A positive result requires the detection of the SARS-CoV-2 viral N gene target. Dots represent identical nucleotides compared to the sequence of RPA amplicon, (“–”) means sequence gaps are not covered by oligonucleotides. Black shadows represent primer binding sequences and blue shadows represent crRNA recognition sequences. “+” means positive and “–” means negative. Fold change value was used to normalize the fluorescence signal values. Fold change (FC) = (F (PC)-B (PC)) / (F (NC)-B (NC)), F = fluorescence signal value of 19 min, B = fluorescence signal value of 0 min, PC = positive control, NC = negative control. The result was shown as mean ± SD, N = 3. ***P < 0.01