A bifunctional aptamer-siRNA chimera targeting ACE2 for the inhibition of SARS-CoV-2 S pseudovirus entry and replication

• A novel DNA aptamer (AA2) targeting human ACE2 was isolated via SELEX, exhibiting high affinity (Kd = 5.41 nM) and blocking SARS-CoV-2 spike RBD binding. • AA2 potently neutralizes SARS-CoV-2 S pseudovirus entry into host cells, demonstrating its potential as a host-directed antiviral. • An aptamer-siRNA chimera (AsiC) combining AA2 with a GFP-targeting siRNA synergistically inhibits viral replication, outperforming monotherapies. • This dual-function AsiC platform offers a promising broad-spectrum strategy against current and future ACE2-dependent coronaviruses.