Posted on Jun 06, 2018, 8 p.m.
A magnetic control system has been devised by researchers at the Ohio State University to make tiny DNA based robots move on demand and do it much faster than previously possible, reducing response time from several minutes to less than a second in the prototype nanorobot, as published in the journal Nature Communications.
This discovery not only represents significant improvements in speed and time but this is also the first direct real time control of DNA based molecular machinery that may one day enable nanorobots to manufacture objects such as drug delivery devices as quickly and reliable as full sized counterparts. Previously DNA could only be moved indirectly in time consuming manners by inducing chemical reactions coaxing movement, or introducing molecules to bind to DNA and reconfigure it. Real time manipulation enable interactions with DNA nanodevices to interact with molecules and molecular systems that could be coupled to nanodevices with direct visual feedback in real time.
Carlos Castro and team created DNA origami techniques which were used in earlier work to fold individual strands of DNA to form simple microscopic tools like hinges and rotors, and a trojan horse was formed out of DNA to deliver drugs to cancer cells. For this study microscopic magnetic tweezers were used, developed by Rathnasingham Sooryakumar and team for moving biological cells made of groups of magnetic particles that move in sync to nudge cells to a desired location, which though invisible to the naked eye are still bigger than the nanorobots. The collaboration was to face the challenges of harnessing the power of magnetic force to probe the hidden astoundingly complex microscopic world by shrinking functionality of their particles a thousand fold, moving them to precise locations on moving parts of the machines incorporating fluorescent molecules as monitoring beacons as they move.
Rods, rotors, and hinges were built using DNA origami. Stiff DNA levers were used to connect the nanoscopic components to miniature beads of polystyrene impregnated with magnetic materials. It was found that by adjusting a magnetic field the particles could be commanded to swing components back and forth or rotated, instructed movements were executed in less than a second.
A nanorotor was able to spin 360 degrees in one second with continuous controlled motion driven by a rotating magnetic field, and a nanohinge was opened or closed in 0.4 seconds and held at a specific angle with precision of 8 degrees, as examples. The movements would have taken several minutes using traditional methods. Complex nanomaterials or biomolecular complexes are envisioned to one day be fabricated in DNA based nanofactories which can detect and respond to local environments.
This interdisciplinary collaboration demonstrates an advance which the researchers are excited to continue building apun. The merging of Castro’s DNA devices and Sooryakumar’s magnetic platform hold great promise for the future.
Materials provided by Ohio State University.
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Stephanie Lauback, Kara R. Mattioli, Alexander E. Marras, Maxim Armstrong, Thomas P. Rudibaugh, Ratnasingham Sooryakumar, Carlos E. Castro. Real-time magnetic actuation of DNA nanodevices via modular integration with stiff micro-levers. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-03601-5