FIGURE 4.

Nucleic acid-based detection of SARS-CoV-2. CRISPR/Cas system: Purified RNA can be amplified in an isothermal instrument using either reverse transcription recombinant polymerase amplification (RT-RPA) or reverse transcription loop-mediated isothermal amplification (RT-LAMP). The amplified product can be reported using either the chromogenic substances in the amplification system or the CRISPR/Cas system for additional specific cleavage of nucleic acids and determination of virus infection. After the guide RNA binds to the CRISPR-associated Cas protein, the resulting complex can specifically cleave the viral nucleic acid sequence. The result can be reported by fluorescence quenching molecules in the reaction, by reporting the fluorescence signal, or by the side stream chromatography color development strip of the cleaved nucleic acid fragment.