Dynamic Programming of a DNA Walker Controlled by Protons

We have now constructed a four-legged DNA walker based on toehold exchange reactions whose movement is controlled by alternating pH changes. A well-characterized, pH-responsive CG-C+ triplex DNA was embedded into a tetrameric catalytic hairpin assembly (CHA) walker. The proton-controlled walker could autonomously move on otherwise unprogrammed micro-particles surface, and the walking rate and steps of walking were efficiently controlled by pH. The starting and stopping of the walker, and its association and dissociation from the micro-particles, could also be dynamically controlled by pH. The simple, programmable, and robust nature of this proton-controlled walker now provides the impetus for the development of a wide variety of more practical nanomachines.