A novel method for high-sensitivity detection of SARS-CoV-2 using dual double-quenched fluorescence probes

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected many people around the world; fast and accurate detection of the virus can help control the spread of the virus. Reverse transcription-polymerase chain reaction (RT-PCR) is the gold standard method for SARS-CoV-2 detection. In this study, we improved the RT-PCR by proposing a novel method using dual double-quenched fluorescence probes. We used the improved probes to detect the plasmid DNA and RNA reference materials of SARS-CoV-2, respectively. The results show that, the background fluorescence intensity reduced by 50%, the fluorescence increment increased to 2.8 folds, and the Ct value significantly reduced by 3 or more, indicating that the detection sensitivity increased at least 8 times. In addition, we demonstrated that the improved probes have well performance in detecting SARS-CoV-2, with the minimum concentration of 6.2 copies/mu L. This study will help biological companies develop better products for SARS-CoV-2 and other clinical pathogen infection. Graphical Abstract Application of improved RT-PCR, with dual double-quenched fluorescence probes for detection of SARS-CoV-2, has led to lower background fluorescence and higher detection sensitivity.