Real Time Actuation Of A Dna Based Robotic Arm

Since the early days of nanotechnology, scientists have dreamt of nanoscale mechanical systems that resemble macroscale industrial assembly lines. Molecular self-assembly with DNA molecules, used for the bottom-up creation of complex molecular constructs, has been shown to hold large potential to push towards a realization of this vision. Starting out from simple mechanical mechanisms, increasingly intricate systems have been demonstrated in the past decade. A wide collection of mechanical elements, potentially used as components for even more elaborate systems have been developed over the past years. These elements were based on a variety of different concepts to facilitate conformational changes, sliding motion and rotation. We here demonstrate a DNA-based molecular robotic arm integrated on a square base plate created with the DNA origami technique, expanding the repertoire of available building components for DNA assembled nanomachines. A flexible connection between base plate and arm allows rotation of the arm with respect to the specifically addressable base plate. Based on a one pot folding approach, the structure efficiently self-assembles. With the help of single-molecule fluorescence techniques, diffusive arm rotation and temporary fixation at different docking positions on the base plate is observed on a millisecond time scale. Utilizing the high intrinsic charge of our DNA nanoconstruct we also demonstrate the use of electrical fields to actively control the arm's angle relative to the base plate. Actuation of the robot arm only requires milliseconds, which is many orders of magnitude faster than established methods for the operation of synthetic DNA nanomachines. For future work, the system promises to act a as versatile rapid prototyping platform for the development of components for molecular assembly lines and highly parallelizable nanoscale force spectroscopy.