Rapid and Visual Detection of SARS-CoV-2 Using Multiplex Reverse Transcription Loop-Mediated Isothermal Amplification Linked With Gold Nanoparticle-Based Lateral Flow Biosensor

Chen, Xu; Zhou, Qingxue; Li, Shijun; Yan, Hao; Chang, Bingcheng; Wang, Yuexia; Dong, Shilei

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that has caused the outbreak of coronavirus disease 2019 (COVID-19) all over the world. In the absence of appropriate antiviral drugs or vaccines, developing a simple, rapid, and reliable assay for SARS-CoV-2 is necessary for the prevention and control of the COVID-19 transmission. METHODS: A novel molecular diagnosis technique, named multiplex reverse transcription loop-mediated isothermal amplification, that has been linked to a nanoparticle-based lateral flow biosensor (mRT-LAMP-LFB) was applied to detect SARS-CoV-2 based on the SARS-CoV-2 RdRp and N genes, and the mRT-LAMP products were analyzed using nanoparticle-based lateral flow biosensor. The mRT-LAMP-LFB amplification conditions, including the target RNA concentration, amplification temperature, and time were optimized. The sensitivity and specificity of the mRT-LAMP-LFB method were tested in the current study, and the mRT-LAMP-LFB assay was applied to detect the SARS-CoV-2 virus from clinical samples and artificial sputum samples. RESULTS: The SARS-CoV-2 specific primers based on the RdRp and N genes were valid for the establishment of mRT-LAMP-LFB assay to detect the SARS-CoV-2 virus. The multiple-RT-LAMP amplification condition was optimized at 63°C for 30 min. The full process, including reaction preparation, viral RNA extraction, RT-LAMP, and product identification, could be achieved in 80 min. The limit of detection (LoD) of the mRT-LAMP-LFB technology was 20 copies per reaction. The specificity of mRT-LAMP-LFB detection was 100%, and no cross-reactions to other respiratory pathogens were observed. CONCLUSION: The mRT-LAMP-LFB technique developed in the current study is a simple, rapid, and reliable method with great specificity and sensitivity when it comes to identifying SARS-CoV-2 virus for prevention and control of the COVID-19 disease, especially in resource-constrained regions of the world.