DNA aptamers in COVID-19 research

Novel coronavirus (SARS-CoV-2), a variant of the severe acute respiratory syndrome (SARS) family has claimed around 1 million lives and more than 33 million people worldwide have been infected. It has been declared a pandemic by the World Health Organization. COVID-19 is transmitted mainly through aerosol droplets from patients (both asymptomatic and symptomatic) to healthy people. Its high rate of transmission demands a quick and early diagnosis of patients followed by urgent quarantine of those affected. Since the SARS-CoV-2 virus is mutating, it is of utmost importance to develop a quick diagnosis against it. The current techniques use either PCR-based methods or antibody-based ELISA methods for diagnosis, which are both time-consuming and expensive. This is the biggest impediment in large-scale diagnosis of COVID-19. Multiple biosensors based on antibodies and aptamers have been reported and tested. Aptamers seem much more lucrative due to ease of synthesis, cost-effectiveness and extremely high degree of sensitivity in terms of detection, less immunogenicity and robustness to modifications. We present the history and characterization of aptamers, their selection strategies and applications to multiple viruses such as HIV, HCV and SARS-CoV. However, to date, no aptamers have been designed against any of the protein components or the genomic RNA of SARS-CoV-2. Based on the success of aptamers against many viruses, we argue for the future exploration of aptamers in the context of SARS-CoV-2 diagnostic testing.