DNA walkers, which are synthetic nanodevices that drive the processive movement of nucleic acids along a well-designed track, have emerged as a powerful tool in biosynthesis, biocomputing, and biosensing due to their exquisite programmability, good biocompatibility, and efficient signal amplification capacity. However, many existing approaches are still hindered by limited reaction kinetics. Herein, we designed a dual spatially localized DNA walker that utilized bipedal catalysts to drive high-speed stochastic movement along three-dimensional tracks via a proximity-driven catalytic hairpin assembly. We demonstrated that the dual colocalization of autocatalytic circuits significantly increased their local concentrations and accelerated reaction kinetics through proximity. We also showed that the use of bipedal catalysts further improved reaction rates compared with unipedal catalysts. Taking advantage of these unique features, we constructed an RNA-responsive PCHA walker for mRNA imaging in live cells, providing a novel and efficient tool for biomolecule detection and biological functions regulation.
Keywords: DNA walker; catalytic hairpin assembly; gold nanoparticle; mRNA detection; spatial localization.