Rotor mechanism assembled from 3-D DNA components. Dietz Lab/TUM
In the 1st machine, a rotor mechanism was formed from interlocking 3D DNA components. Another has a hinged molecular manipulator, also made from DNA. These are just the latest steps in a campaign to transform so-called “DNA origami” into an industrially useful, commercially viable technology.
Inspired by nature’s nanomachines – such as the enzyme ATP synthase and the motor-driven flagella of bacteria – physicists in Prof. Hendrik Dietz’s lab at TUM keep expanding their own design and construction repertoire. They have systematically developed rules and procedures for creating self-assembled DNA origami structures with ever greater flexibility and control. Moving from DNA basepair matching to shape-complementary building techniques – with a variety of interlocking “bricks” – the researchers’ toolkit has advanced steadily in the direction of higher-level programming and modular assembly.
Molecular manipulator made from DNA, with TEM images. Dietz Lab/TUM
In step with this, they have honed methods to verify,eg that a particular soup of nanoparticles really is packed with copies of whatever they designed: whether a switchable gear, an artificial membrane channel, an arbitrarily complicated test object, a “nanobook” that opens and closes, or a robot figure with movable arms. The latest additions to the lab’s zoo of DNA origami objects, 2 tiny 3D machines with moving parts.
A rotory mechanism was built from 3 multilayer DNA building blocks: a rotor unit, with a body ~32nm long and a longer, lever-like extension; and 2 clamp elements that “click” together to form an axle bearing. The parts join with a tight fit and leave just 2 nanometers of play around the axle, allowing the rotor to swing but not to wobble. In one variant, the arm will rotate freely between random stopping points; in another, it will dwell in specified positions the researchers call docking sites. To date, this is the most complex rotary structure realized using DNA origami techniques.
To be clear, the rotor has no motor: It is propelled by Brownian motion, random movement of particles in solution. Tthe researchers open the way for active devices under chemical or thermal power and control. “It’s like having built an engine,” Dietz says. “Now spark plugs and combustible uel are the next items on the to-do list.”
Rotor mechanism assembled from 3-D DNA components. Dietz Lab/TUM
In a separate project, Dietz and Funke created a hinged machine on a scale suitable for manipulating individual molecules with atomic precision. The angle between the gripper’s 2 main structural elements can be controlled with DNA helices. Experiments with this DNA origami positioning device showed that it could be capable of precisely placing molecules, adjusting the distance between them in steps as small as the radius of a H atom. This work moves toward building arger DNA origami devices without pushing the limits of precision. It hints at ways DNA nanomachines might someday be useful to control chemical reactions.
Its mobility is such that it could do up to 50,000 rpm if every rotary step it took would go only in one direction. In the next generation of devices, we will use the placement precision to couple chemical reactions to the movements of a rotor. This has the potential to result in a motor. This device, then, could be used for all kinds of purposes, such as actively propelling nanoscale drug-delivery vehicles, pumping and separating molecules across barriers, or packaging molecules into cargo compartments.” http://www.tum.de/en/about-tum/news/press-releases/short/article/32983/
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