Comparison of 6 aptamer-aptamer pairs on rapid detection of SARS-CoV-2 by lateral flow assay.

BACKGROUND:SARS-CoV-2 is a threat for humanity. Both the Spike (S) protein and its receptor binding domain (sRBD) are extensively used for the rapid detection. Although real time reverse transcription polymerase chain reaction (rRT-PCR) is mostly used method for the molecular detection of SARS-CoV-2, rapid assays for antigenic detection is always needed. Lateral flow assays (LFAs) are the most commonly used tests for this purpose and aptamers having stability and long shelf life are used as capture reagents. OBJECTIVE:This study aimed to develop the LFAs based on the aptamer pairs for the antigenic detection of SARS-CoV-2 with naked eye. METHODS:Gold nanoparticles (AuNPs) were used as label and six sandwich models by three different aptamers were prepared using 4 μM and 8 μM probes and two kinds of membranes for developing the LFAs. RESULTS:8 μM probe concentration and M2 membrane showed the best recognition of both the synthetic sRBD and SARS-CoV-2 coming from the naso/oropharingeal swabs by designed LFAs as 100% sensitivity and 93,3% specifity compared to the antibody detecting LFAs. CONCLUSIONS:Our developed strip assays based on aptamer pairs recognized the target, directly in a 5-6 minutes with naked eye. It was also concluded that aptamer pairs, membrane types, assay buffers and probe concentrations have significant role in the detection of SARS-CoV-2 by LFAs. HIGHLIGHTS:The detection of SARS-CoV-2 in clinical samples was demonstrated with the best aptamer pairs, sensitively and selectively among the designed 6 aptamer pairs for LFAs. Developed LFAs can be an alternative method to the conventional antibody based LFAs for SARS-CoV-2 detection.