Development of Reverse Transcription Loop-mediated Isothermal Amplification (RT-LAMP) Assays Targeting SARS-CoV-2

Gun-Soo Park; Keunbon Ku; Seung-Hwa Beak; Seong Jun Kim; Seung Il Kim; Bum-Tae Kim; Jin-Soo Maeng

Third and fourth rounds of screening were done by checking sensitivity to dilutions of cDNA and RNA, respectively. Five out of seven primer sets showed specific amplification for at least one replicate of . CC-BY-NC-ND 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.09.983064 doi: bioRxiv preprint duplicate with cDNA concentration corresponding to 1.7 x 10 1 copies of input RNA (Supplementary Figure 1) . Next, we evaluated sensitivity of the five primer sets to RNA dilutions in RT-LAMP using Bst3.0 and SuperScript IV Reverse Transcriptase. Two primer sets, both targeting Nsp3, showed best sensitivity that showed specific amplification at 10 -6 dilution of RNA (Figure 1) . We also added two primer sets, one targeting S and the other targeting N, for reaction optimization experiments as they showed fast threshold time for cDNA and to keep ranges of target genes. Primer sequences are represented in Table 1 .