Two kinds of DNA enzyme-powered bidirectional one-dimensional DNA walking nanomachine for payload release and...

Herein, we present a target-triggered bidirectional one-dimensional (1D) DNA walking nanomachine, built from a well-designed track, which could simultaneously move two different DNA walkers to the opposite direction along the track and release payload. This track is composed of a DNA walker station (chain S3) in the middle of track for storing two kinds of DNA walker (W1 and W2), and corresponding two kinds of payload conjugated DNA stators (chain S1, S2 and S4, S5) for the moving of walker on the two flanks of chain S3 respectively. Moreover, the chain S3 also serves as a target-assisted amplification platform based on a catalytic hairpin assembly (CHA)-like strategy. In the presence of target (nucleic acid), the dynamic assembly between hairpin (HP) and S3 is triggered for multiple recycling of target and releasing of W1 and W2. Since the W1 and W2 respectively correspond to 8-17 DNAzyme and 10-23 DNAzyme, they could cleave the RNA substrates with sequence specificity to move towards two opposite directions along the track at the same time, accompanying the release of payloads. Such a 1D DNA walking nanomachine is not only could propel the walker to move in two directions respectively but also improve the locomotion efficiency compared to the traditional single-directional 1D DNA walking nanomachine with the same amounts of stators. This concept of inducing the locomotion manner change on a 1D DNA device may provide a thought to facilitate the development of DNA dynamic nanomachines and intelligent nanosensors.