Rapid Molecular Detection of SARS-CoV-2 (COVID-19) Virus RNA Using Colorimetric LAMP

Yinhua Zhang; Nelson Odiwuor; Jin Xiong; Luo Sun; Raphael Ohuru Nyaruaba; Hongping Wei; Nathan A Tanner

We designed 5 sets of LAMP primers targeting two fragments (Table 1) of SARS-CoV-2 sequence (GenBank accession number MN908947) using the online software Primer Explorer V5 (available for free use at: https://primerexplorer.jp/e/). DNA fragments containing these two regions were synthesized as gBlocks (Integrated DNA Technologies) and T7 RNA polymerase promoters were added by PCR (NEB M0493, numbers indicate NEB catalog ID unless otherwise noted) using primer pairs where one primer containing the promoter sequence. RNAs were then synthesized by in vitro transcription (E2050) using these PCR products as templates and purified using RNA clean up columns (T2040). The resulting RNAs as well as the gBlocks were serially diluted in 10-fold increments using 0.1x TE buffer containing 0.01% Tween 20. RT-. CC-BY 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity. were allowed to cool at room temperature before further processing. If the samples were not for use immediately, they were stored at 4 °C.