Combined recombinase polymerase amplification/rkDNA–graphene oxide probing system for detection of SARS-CoV-2

The development of rapid, highly sensitive, and selective methods for the diagnosis of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) should help to prevent the spread of this pandemic virus. In this study, we combined recombinase polymerase amplification (RPA), as a means of isothermal DNA amplification, with an rkDNA–graphene oxide (GO) probe system to allow the rapid detection of SARS-CoV-2 with high sensitivity and selectivity. We used in situ enzymatic synthesis to prepare an rkDNA probe that was complementary to an RPA-amplified sequence of the target N-gene of SARS-CoV-2. The fluorescence of this rkDNA was perfectly quenched in the presence of GO. When the quenched rkDNA–GO system was added to the RPA-amplified sequence of the target SARS-CoV-2, the fluorescence recovered dramatically. The combined RPA/rkDNA–GO system exhibited extremely high selectivity (discrimination factor: 17.2) and sensitivity (LOD = 6.0 aM) for the detection of SARS-CoV-2. The total processing time was only 1.6 h. This combined RPA/rkDNA–GO system appears to be a very efficient and simple method for the point-of-care detection of SARS-CoV-2. A combined RPA/rkDNA–GO probing system allows the diagnosis of COVID-19 (SARS-CoV-2) with high in selectivity (discrimination factor: 17.2) and sensitivity (LOD: 6.0 aM) within 1.6 h. [Display omitted] •Detection of SARS-CoV-2 using a combination of recombinase polymerase amplification (RPA) and rkDNA–graphene oxide.•The combined RPA/rkDNA-GO probe system exhibited high selectivity and sensitivity for the diagnosis of COVID-19.•Simple processing for the rapid (1.6 h) diagnosis of COVID-19 (SARS-CoV-2).