A non-enzymatic, isothermal strand displacement and amplification assay for rapid detection of SARS-CoV-2 RNA

Mohammadniaei, Mohsen; Zhang, Ming; Ashley, Jon; Christensen, Ulf Bech; Friis-Hansen, Lennart Jan; Gregersen, Rasmus; Lisby, Jan Gorm; Benfield, Thomas Lars; Nielsen, Finn Erland; Henning Rasmussen, Jens; Pedersen, Ellen Bøtker; Olinger, Anne Christine Rye; Kolding, Lærke Tørring; Naseri, Maryam; Zheng, Tao; Wang, Wentao; Gorodkin, Jan; Sun, Yi

The current nucleic acid signal amplification methods for SARS-CoV-2 RNA detection heavily rely on the functions of biological enzymes which imposes stringent transportation and storage conditions, high cost and global supply shortages. Here, a non-enzymatic whole genome detection method based on a simple isothermal signal amplification approach is developed for rapid detection of SARS-CoV-2 RNA and potentially any types of nucleic acids regardless of their size. The assay, termed non-enzymatic isothermal strand displacement and amplification (NISDA), is able to quantify 10 RNA copies.µL(−1). In 164 clinical oropharyngeal RNA samples, NISDA assay is 100 % specific, and it is 96.77% and 100% sensitive when setting up in the laboratory and hospital, respectively. The NISDA assay does not require RNA reverse-transcription step and is fast (<30 min), affordable, highly robust at room temperature (>1 month), isothermal (42 °C) and user-friendly, making it an excellent assay for broad-based testing.