Neutralizing Aptamers Block S/RBD‐ACE2 Interactions and Prevent Host Cell Infection

The receptor‐binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 spike (S) protein plays a central role in mediating the first step of virus infection to cause disease: virus binding to angiotensin‐converting enzyme 2 (ACE2) receptors on human host cells. Therefore, S/RBD is an ideal target for blocking and neutralization therapies to prevent and treat coronavirus disease 2019 (COVID‐19). Using a target‐based selection approach, we developed oligonucleotide aptamers containing a conserved sequence motif that specifically targets S/RBD. Synthetic aptamers had high binding affinity for S/RBD‐coated virus mimics (KD≈7 nM) and also blocked interaction of S/RBD with ACE2 receptors (IC50≈5 nM). Importantly, aptamers were able to neutralize S protein‐expressing viral particles and prevent host cell infection, suggesting a promising COVID‐19 therapy strategy. Synthetic ssDNA aptamers containing a conserved sequence motif that specifically targets the receptor‐binding domain (RBD) of the SARS‐CoV‐2 spike have the capacity to neutralize the virus and prevent host cell infection in vitro, suggesting a new therapeutic approach to treat COVID‐19.