Paper-based All-in-One PCR Device for Detection of SARS-CoV-2 in Saliva Sample at Point-of-Care Testing

Abstract

Molecular diagnosis is used for detecting pathogens. It overwhelms conventional diagnostics such as the culture method. Nowadays, PCR is one of the major diagnostics for SARS-CoV-2. The conventional PCR spends 90 min to 130 min. It is inconvenient as requiring professionals to operate diagnosis. The components it uses are expensive because of many polymerases and operation resources. The PCR uses a nasopharyngeal swab which gives the patient a painful and uncomfortable experience. Lastly, extraction including centrifugation is necessary for the conventional PCR. However, the all-in-one molecular diagnosis device we developed only spends about 45 min. The device is conveniently operated based on the lateral flow paper membrane structure. After sample injection, the device is performed automatically with dried reagents. The cost is decreased by the components consumption reduction and operation simplification. We combined pretreatment and detection using proteinase K and LFA although it uses saliva, including a lot of RNase and mucus. The proteinase K digests PCR-interrupting proteins to enhance the detection. Even though conventional PCR has better efficiency for high throughput screening, the all-in-one PCR device is better for lockdown-necessary infectious disease and selective demands. Consequently, a paper-based PCR device is developed, which combines retreatment, PCR reaction, and detection.