Inhibition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and excessive in ammation is the current task in the prevention and treatment of COVID-19. Here, we designed a dualfunction circular aptamerASO chimera (circSApt-NASO) to suppress SARS-CoV-2 replication and in ammation. The chemically unmodi ed circSApt-NASO exhibited high serum stability by arti cial cyclization, signi cantly enhancing the utility of oligonucleotides. It presents great e ciency in knocking down, demonstrating the superiority of the circular ASO as a novel tool for sequence-speci c silencing of gene expression. Furthermore, we propose and demonstrate that the SApt binding to spike protein enables the chimera to be e ciently delivered into the susceptible host cells expressing ACE2 along with the infection of SARS-CoV-2. At high concentrations of SARS-CoV-2, the e ciency of targeted delivery of circSApt-NASO can even be compared to transfection. Among them, the anti-spike aptamer (SApt) that blocks the Spike-TLR4 interaction potently inhibits spike-induced in ammation. The NASO targeting to silence N genes not only display robust anti-N-induced in ammatory activity, but also achieve e cient inhibition of SARS-CoV-2 replication. Therefore, bene ting from the high stability of the cyclization, antispike aptamer-dependent and viral infection-mediate targeted delivery, the circSApt-NASO displays robust potential against authentic SARS-CoV-2 and Omicron (B.1.1.529), providing a promising speci c antiin ammatory and anti-proliferative reagent for therapeutic COVID-19 based on the oligonucleotide therapeutics strategy.

Inhibition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and excessive inflammation is the current task in the prevention and treatment of COVID-19. Here, we designed a dual-function circular aptamerASO chimera (circSApt-NASO) to suppress SARS-CoV-2 replication and inflammation. The chemically unmodified circSApt-NASO exhibited high serum stability by artificial cyclization, significantly enhancing the utility of oligonucleotides. It presents great efficiency in knocking down, demonstrating the superiority of the circular ASO as a novel tool for sequence-specific silencing of gene expression. Furthermore, we propose and demonstrate that the SApt binding to spike protein enables the chimera to be efficiently delivered into the susceptible host cells expressing ACE2 along with the infection of SARS-CoV-2. At high concentrations of SARS-CoV-2, the efficiency of targeted delivery of circSApt-NASO can even be compared to transfection. Among them, the anti-spike aptamer (SApt) that blocks the Spike-TLR4 interaction potently inhibits spike-induced inflammation. The NASO targeting to silence N genes not only display robust anti-N-induced inflammatory activity, but also achieve efficient inhibition of SARS-CoV-2 replication. Therefore, benefiting from the high stability of the cyclization, anti-spike aptamer-dependent and viral infection-mediate targeted delivery, the circSApt-NASO displays robust potential against authentic SARS-CoV-2 and Omicron (B.1.1.529), providing a promising specific anti-inflammatory and anti-proliferative reagent for therapeutic COVID-19 based on the oligonucleotide therapeutics strategy.