Pdot-Enabled Point-of-Care Digital PCR for Sensitive Detection of SARS-CoV-2

Project SummaryCurrent SARS-CoV-2 molecular diagnosis tests mostly are based on real-time quantitative PCR(qPCR). Digital PCR is a next-generation PCR technology based on limiting dilution, end-pointPCR, and Poisson statistics. Digital PCR transforms the exponential, analog nature of qPCRquantification into a linear, digital signal quantification. Compared to qPCR, digital PCR offersseveral important advantages, including its ability to provide absolute quantification, tolerance toinhibitors/contaminants, and its high sensitivity.Two recent studies showed digital PCR has improved sensitivity for picking up COVID-19 thatqPCR had missed. In addition, for some patients, results on SARS-CoV-2 infections from qPCRvaried from day to day. But unlike qPCR, digital PCR showed consistent reproducible results.Overall, digital PCR was shown to reduce significantly false-negative results, which isparticularly useful for diagnosing early or asymptomatic infections or for testing convalescentpatients before discharge.Current fluorescent probes used in qPCR, such as FAM (a fluorescein dye), do not have thebrightness to be visualized with a cell-phone type camera. To address this issue and to enablesimple cell-phone readout of digital PCR results in a point-of-care setting, this project aims todevelop Pdots into ultrabright probes for digital PCR assays that can provide sensitive detectionof SARS-CoV-2.