Efficient Multidriven Strand Displacement Reaction for Biosensing

A key challenge for achieving high-efficient DNA strand displacement reaction (SDR) with existing technologies is the inferior kinetic performance due to the alternately cumbersome conjunction and dissociation of dsDNA. In this work, a novel multidriven SDR collaborated by toehold initiator, strand towing, and click chemistry is engineered. The invasion strand (O) endows the hybridization with a basal strand (M) in dsDNA for releasing a displacement strand (P), which can be significantly boosted by the towing of a helper strand and impetus from the click reaction. Accordingly, the hybridization rate and dissociation extent of P can be largely improved and showed a desiring displacement rate close to 6-fold compared with the traditional method, providing a newly high-efficient SDR strategy for potential application in biosensing, clinical diagnostics, and DNA nanotechnology. In view of this, a practical biosensing platform by combining the multidriven SDR (MSDR) with waste-free DNA multi-cycle amplification is constructed for the rapid and ultrasensitive electrochemical detection of cancer-related miRNA-21. The substantial output DNA as an invasion strand (O) from target-triggered waste-free DNA multicycle can high-efficiently release a signal probe (Fc)-labeled displacement strand (P) on an electrode by using the proposed MSDR, obtaining a low detection limit below 106.8 aM.