SARS-CoV-2 detection via high-sensitivity RT-PCR in 15 minutes using microfluidic COP chips

The Moving-Plug PCR System, developed by Fraunhofer IMM, is a portable device that dramatically accelerates PCR reaction speeds by eliminating the time-consuming heating and cooling cycles traditionally used in thermal cycling. Instead, the reaction sample is moved between preheated hot and cool zones. When combined with a SARS-CoV-2 PCR kit, we successfully conducted 40 PCR cycles and achieved quantitative detection of SARS-CoV-2 RNA in 15 minutes, which is more than 2x faster than using a thermocycler. This innovation demonstrates significant potential for rapid and sensitive diagnostic applications. The polymerase used in our SARS-CoV-2 PCR kit can transcribe RNA into cDNA during the first step of PCR. This omits the need for an additional reverse transcriptase step before PCR, therefore quantitative results could be achieved in 15 minutes. The use of polycarbonate as a chip material required the addition of betaine in the PCR to overcome its limitations, while cyclic olefin copolymer was evaluated as chip material without the addition of betaine. The sensitivity achieved using a cyclic olefin copolymer chip was equivalent to that obtained with a commercially PCR thermocycler. Notably, it was also possible to detect RNA effectively in heat-inactivated saliva samples, which further enhances its applicability in real-world settings. These findings can help overcome the disadvantages of traditional diagnostic methods, such as the long testing times of traditional PCR assays or the lack of sensitivity of Enzyme-linked Immunosorbent Assay. For future infectious disease outbreaks a fast Point-of-Care-PCR Technology with short result reporting times and adequate sensitivity is achieved.