Scientists have created the world's first working nanoscale electric motor, according to research published in the journal Electric Motors. natural nanotechnology. The science team designed a DNA-engineered turbine driven by hydrodynamic flows inside nanopores, nanometer-sized holes in a solid silicon nitride membrane.
These tiny motors could help spark research into future applications, including building molecular factories for useful chemicals or medical probes for molecules in the bloodstream to detect diseases like cancer.
“Ordinary macroscopic machines are inefficient at the nanoscale,” said co-author Aleksei Aksimentiev, professor of physics at the University of Illinois at Urbana-Champaign. “We need to develop new principles and physical mechanisms to realize electric motors on a very small scale.”
Experimental work on small motors was carried out by Cees Dekker at the Delft University of Technology and Hendrik Dietz at the Technical University of Munich.
Dietz is a world expert in DNA origami. His lab manipulated DNA molecules to create tiny motorized turbines. The turbine consists of 30 double-stranded DNA helices designed as an axis and three blades about 72 base pairs long. Decker's lab demonstrated that a turbine could actually spin by applying an electric field. Aksimentiev's lab performed all-atom molecular dynamics simulations on a system of 5 million atoms to characterize the physics of how the motor operates.
The system was the smallest representation that would yield meaningful results for the experiment. But Aksimentiev said, “This was one of the largest things ever simulated from a DNA origami perspective.”
From Mission Impossible to Mission Possible
The Texas Advanced Computing Center (TACC) has awarded Aksimentiev a leadership resource allocation to support research on mesoscale biological systems at the National Science Foundation (NSF)-funded Frontera, the nation's leading academic supercomputer.
“Frontera has played an important role in this DNA nanoturbine research,” said Aksimentiev. “Instead of waiting a year or more on a small-scale computing system, we got microsecond simulation trajectories in two to three weeks,” Aksimentiev said. “Large-scale simulations were performed on Frontera using about a quarter of the system, or over 2,000 nodes.” He said. “But it’s not just the hardware that’s important, it’s also the interaction with TACC staff. It’s very important to make the most of our resources when opportunities arise.”
Aksimentiev also received supercomputer allocations for this work from the NSF-funded San Diego Supercomputer Center in the Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS) and Purdue University's Anvil.
“We had up to 100 different nanomotor systems to simulate. We had to run them in a fast way under a variety of conditions, which the ACCESS supercomputer supported perfectly,” said Aksimentiev. “We are very grateful for the support of NSF. Without these systems, we would not be able to do the science we do.”
DNA as a building block
The success of the operational DNA nanoturbine builds on previous research using the Frontera and ACCESS supercomputers. Studies have shown that a single DNA helix is the smallest electric motor that can be built and can spin at up to one billion revolutions per minute.
According to Aksimentiev, DNA has emerged as a building material at the nanoscale.
“DNA base pairs are a very powerful programming tool. By simply programming the sequences of letters that make up the rungs of the double helix, we can use Cadnano software to program geometric, three-dimensional objects in DNA,” he explained.
Another reason to use DNA as a building block is that it carries a negative charge, a property essential for building electric motors.
“We wanted to recreate one of the coolest biological machines – ATP synthase driven by an electric field. We decided to make the motor out of DNA,” said Aksimentiev.
“This new research is the first nanoscale motor that can control the speed and direction of rotation,” he added. This is achieved by adjusting the electric field of the solid nanopore membrane and the salt concentration of the fluid surrounding the rotor.
“In the future, new nanoscale electric motors could be used to synthesize molecules, or they could be used as elements of larger molecular factories that move things around. The synthetic system could enter the bloodstream and interrogate molecules or cells one at a time. Aksimentiev said there is a need for momentum.
If you're thinking this sounds like a scene from a 1960s science fiction movie, you're right. In the film Fantastic Voyage, a team of Americans aboard a nuclear submarine are scaled down and injected into a scientist's body to fix a blood clot, and must work quickly before the miniaturization ends.
It may sound incredible, but Aksimentiev says something like this could happen with the concepts and elements of the machines we are currently developing.
“We were able to achieve this thanks to supercomputers,” Aksimentiev said. “Supercomputers are becoming increasingly indispensable as the complexity of the systems we build increases. Supercomputers are computational microscopes that can see the movement of individual atoms at ultimate resolution and how they fit together into larger systems.”
Funding came from ERC Advanced Grant no. 883684 and the NanoFront and BaSyC programs; ERC Integrator Grant National Science Foundation grant DMR-1827346 to HD (GA no. 724261), the Gottfried-Wilhelm-Leibniz program (HD), and the Deutsche Forschungsgemeinschaft through SFB863 project ID 111166240 TPA9; Max Planck School Matter to Life and MaxSynBio Consortium. Supercomputer time was provided by Frontera through TACC Leadership Resource Allocation MCB20012 and ACCESS allocation MCA05S028.