The coronavirus disease 2019 (COVID-19) pandemic has highlighted the major shortcoming of healthcare systems globally in their inability to diagnose the disease rapidly and accurately. At present, the molecular tests (RT-PCR) based approaches to diagnose COVID-19 use reverse transcriptase to create and amplify cDNA from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. Although molecular tests are reported to be specific, false negatives are common. Furthermore, all these tests require a step involving RNA isolation which does not make them POC tests in the true sense.<br/>Here, we report an amplification-free nucleic acid test (NAT), implemented on a lateral flow strip and devoid of a RNA isolation step, which allows rapid diagnosis of positive (nCOV/COVID-19) cases at POC. The assay uses highly specific fluorescein isothiocyanate (FITC) and biotin labeled antisense oligonucleotides (ASOs) as probes that are designed to target N-gene sequence of SARS-CoV-2. Additionally, we used cysteamine capped gold nanoparticles (cyst-AuNPs) for signal augmentation without an additional operation step in lateral flow strip. Without large-stationary equipment and highly trained staffers, the entire contiguous sample-to-answer workflow takes less than 30 minutes from a clinical swab sample to a diagnostic result. Moreover, the assay achieved an accuracy and specificity of almost 100% when tested with 30 clinical samples and confirmed using the FDA-approved RT-PCR COVID-19 diagnostic kit.<br/>In summary, we have designed and tested a nucleic acid test implemented in a lateral flow strip for SARS-CoV-2 RNA detection that enables one to interpret the diagnostic results rapidly, accurately, and visually from clinical samples without professional instruments and expertise. We anticipate that our inexpensive amplification-free detection of SARS-CoV-2 RNA could facilitate a platform for rapid and POC diagnosis of COVID-19 and other emerging infectious diseases in resource deficient areas.

RNA extraction-free rapid detection of SARS-CoV-2 in clinical samples based on lateral flow assay

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.