From Static Scaffolds to Dynamic Highways: Spatially Ordered Nanotube Tracks Improve Pathway Control and Accelerate DNA Walker Kinetics for Enhanced MicroRNA Detection

DNA walkers are programmable molecular machines whose performance depends on the structural precision and spatial organization of their walking tracks. This study presents a rigid and highly ordered DNA nanotube-based track (H-DNT), consisting of periodic anchoring sites spaced 7 nm apart, constructed via the precise self-assembly of single-stranded tiles. Compared to conventional double-stranded or nanosheet DNA tracks, H-DNT significantly improved path controllability and accelerated reaction kinetics, reducing the equilibrium time to only 30 min. By tuning both track length and intertrack spacing, we were able to substantially improve walker motility and signal amplification efficiency. As a proof of concept, the H-DNT system was integrated into an electrochemiluminescence (ECL) biosensing platform for the ultrasensitive detection of microRNA-221 at a concentration as low as 2.42 aM. The platform also had excellent selectivity and stability. This programmable nanodevice provides a robust and generalizable solution for constructing high-performance DNA walker systems, opening new avenues for rapid and sensitive tumor biomarker detection.