title: DNA Bipedal Motor Achieves a Large Number of Steps Due to Operation Using Microfluidics-Based Interface.
abstract: Realization of bioinspired molecular machines that can perform many and diverse operations in response to external chemical commands is a major goal in nanotechnology, but current molecular machines respond to only a few sequential commands. Lack of effective methods for introduction and removal of command compounds and low efficiencies of the reactions involved are major reasons for the limited performance. We introduce here a user interface based on a microfluidics device and single-molecule fluorescence spectroscopy that allows efficient introduction and removal of chemical commands and enables detailed study of the reaction mechanisms involved in the operation of synthetic molecular machines. The microfluidics provided 64 consecutive DNA strand commands to a DNA-based motor system immobilized inside the microfluidics, driving a bipedal walker to perform 32 steps on a DNA origami track. The microfluidics enabled removal of redundant strands, resulting in a 6-fold increase in processivity relative to an identical motor operated without strand removal and significantly more operations than previously reported for user-controlled DNA nanomachines. In the motor operated without strand removal, redundant strands interfere with motor operation and reduce its performance. The microfluidics also enabled computer control of motor direction and speed. Furthermore, analysis of the reaction kinetics and motor performance in the absence of redundant strands, made possible by the microfluidics, enabled accurate modeling of the walker processivity. This enabled identification of dynamic boundaries and provided an explanation, based on the "trap state" mechanism, for why the motor did not perform an even larger number of steps. This understanding is very important for the development of future motors with significantly improved performance. Our universal interface enables two-way communication between user and molecular machine and, relying on concepts similar to that of solid-phase synthesis, removes limitations on the number of external stimuli. This interface, therefore, is an important step toward realization of reliable, processive, reproducible, and useful externally controlled DNA nanomachines.
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer Sheva, 84105, Israel.
authors.forename: Toma E
authors.identifier: 0000-0003-2996-3823
authors.initials: TE
authors.lastname: Tomov
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer Sheva, 84105, Israel.
authors.forename: Roman
authors.initials: R
authors.lastname: Tsukanov
authors.affiliation: Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University , Ramat-Gan 5290002, Israel.
authors.forename: Yair
authors.initials: Y
authors.lastname: Glick
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer Sheva, 84105, Israel.
authors.forename: Yaron
authors.initials: Y
authors.lastname: Berger
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer Sheva, 84105, Israel.
authors.forename: Miran
authors.initials: M
authors.lastname: Liber
authors.affiliation: Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University , Ramat-Gan 5290002, Israel.
authors.forename: Dorit
authors.initials: D
authors.lastname: Avrahami
authors.affiliation: Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University , Ramat-Gan 5290002, Israel.
authors.forename: Doron
authors.initials: D
authors.lastname: Gerber
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer Sheva, 84105, Israel.
authors.forename: Eyal
authors.identifier: 0000-0002-6656-3282
authors.initials: E
authors.lastname: Nir
mesh_terms: D001696:Biomechanical Phenomena; D004247:DNA / Q000737:chemistry*; D031541:Fluorescence Resonance Energy Transfer; D061925:Immobilized Nucleic Acids / Q000737:chemistry*; D007700:Kinetics; D056656:Lab-On-A-Chip Devices; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D000072760:Single Molecule Imaging; D013499:Surface Properties
chemical_list: D061925:Immobilized Nucleic Acids; D004247:DNA
keywords: DNA machines; DNA motors; DNA nanotechnology; microfluidics; single-molecule fluorescence; sm-FRET