Multiple detection of SARS-CoV-2 in point -of -care tests

The global spread of SARS-CoV-2 has highlighted the importance of rapid diagnostic systems and made the development of reliable tests a priority. N and S proteins, which play important roles in the structure and infectivity of SARS-CoV-2, have been identified as primary diagnostic markers due to their strong antigenic properties. Existing diagnostic methods such as LFAs have generally used single aptamers or combinations of antibodies, antibody-aptamer, and antibody-antibody sandwiches to capture these viral proteins. The development of LFA with aptamer cocktails has not been reported yet. In this study, a mLFA was developed for the rapid and accurate detection of SARS-CoV-2. In our study, aptamer cocktails conjugated to AuNPs were used to target N and S proteins of SARS-CoV-2 separately. Thus, both target proteins were detected simultaneously in a single test strip. AuNP-conjugated aptamers bound to targets in the test format were used as detection and labeling agents. Target protein-specific detector aptamers were immobilized on the test strips to form a sandwich complex. Our study showed that the positioning of the detector aptamers on the test strip played an important role in the effectiveness of the test. Appropriate aptamer placement increased the detection accuracy, while different positioning decreased the test efficiency. Overall, the prepared mLFA eliminated the possibility of false positive or false negative viral diagnosis and increased the accurate diagnosis potential of the LFA system. Thus, the designed mLFA constituted an alternative test prototype for real-time clinical testing that is easy to use, inexpensive and has increased accuracy.