Figure 3.

Current efforts of aptamer application for COVID-19. Aptamers can be engineered for the development of effective and affordable diagnostics, therapeutics, and prophylactic vaccines for SARS-CoV-2. Rapid and accurate detection methods, as well as smart vaccine and drug designs with SARS-CoV-2 targeting capabilities, are critically needed. The ASSURED (affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable to the end user) diagnostic criteria is recommended by WHO. The mode of entry for SARS-CoV-2 into host cells occurs through clathrin-mediated endocytosis which depends on the binding interaction between the receptor-binding domain (RBD, Arg319-Phe541) at the C-terminus of spike proteins (S) of SARS-CoV-2 and the host cellular receptors, ACE2, along with S proteins priming by host cell transmembrane serine protease 2 (TMPRSS2). Coronaviruses have four structural proteins, i.e., spike (S), envelope (E), membrane (M) and nucleocapsid (N) that facilitate interactions with the host cell and activities within the host after internalization [108]. On the basis of the sequence similarity between SARS-CoV and SARS-CoV-2, modifications in sequence and structure of SARS-CoV aptamers may produce specific aptamers for SARS-CoV-2 proteins, including N [118].