Centrifugal microfluidic-based multiplex recombinase polymerase amplification assay for rapid detection of SARS-CoV-2

The COVID-19 pandemic has spread worldwide, and rapid detection of the SARS-CoV-2 virus is crucial for infection surveillance and epidemic control. This study developed a centrifugal microfluidics-based multiplex reverse transcription re-combinase polymerase amplification (RT-RPA) assay for endpoint fluorescence detection of the E, N, and ORF1ab genes of SARS-CoV-2. The microscope slide -shaped microfluidic chip could simultaneously accomplish three target genes and one reference human gene (i.e., ACTB) RT-RPA reactions in 30 min, and the sensitivity was 40 RNA copies/reaction for the E gene, 20 RNA copies/reaction for the N gene, and 10 RNA copies/reaction for the ORF1ab gene. The chip demonstrated high specificity, reproducibility, and repeatability. Chip perfor-mance was also evaluated using real clinical samples. Thus, this rapid, accurate, on-site, and multiplexed nucleic acid test microfluidic chip would significantly contribute to detecting patients with COVID-19 in low-resource settings and point-of-care testing (POCT) and, in the future, could be used to detect emerging new variants of SARS-CoV-2.

Automated summary

This study developed a centrifugal microfluidics-based multiplex RT-RPA assay for rapid detection of SARS-CoV-2. The microfluidic chip could simultaneously detect three target genes and one reference gene, with high sensitivity and specificity. It has the potential to be used for point-of-care testing and detection of emerging SARS-CoV-2 variants.