Soft interface confined DNA walker for sensitive and specific detection of SARS-CoV-2 variants.

Nucleic acid detection is conducive to preventing the spread of COVID-19 pandemic. In this work, we successfully designed a soft interface confined DNA walker by anchoring hairpin reporter probes on cell membranes for the detection of SARS-CoV-2 variants. In the presence of target RNA, the cyclic self-assembly reaction occurred between hairpin probes H1 and H2, and the continuous walking of target RNA on cell membranes led to the gradual amplification of fluorescence signal. The enrichment of H1 on membranes and the unique fluidity of membranes promoted the collision efficiency between DNA strands in the reaction process, endowing this method with high sensitivity. In addition, the double-blind test of synthetic RNA in 5% normal human serum demonstrated the good stability and anti-interference in complex environment of this method, which exhibited great potential in clinical diagnostics.