Engineered DNA Make Nano-Machines

Engineers have built simple folding machines the size of molecules out of snips of synthetic and natural DNA. The nano-machines, like the opening and closing hinges shown above, can repeatedly perform the task for which they are designed.

Mechanical engineers at The Ohio State University built these objects using the long-understood principles of human-sized machine design. They say this approach to building 3-D constructs out of DNA is different from other groups, which are instead trying to build complex, static shapes or mimicking the structure of biological systems.

“Nature has produced incredibly complex molecular machines at the nanoscale, and a major goal of bio-nanotechnology is to reproduce their function synthetically,” said Carlos Castro, the group project leader and an assistant professor of mechanical and aerospace engineering. “In essence, we are using a bio-molecular system to mimic large-scale engineering systems to achieve the same goal of developing molecular machines.”

Castro says the work could eventually lead to tiny robots that deliver medicines to targeted areas inside the body and perform diagnostic functions.

To get their DNA machines to work in a predictable way, the team made parts that are meant to flex out of single-stranded DNA. Regions that are supposed to remain stiff are built from snips of double-stranded DNA. For the opening and closing movement in the hinges above to be reversible, the engineers attached small strands of synthetic DNA off the sides of main components. These can latch onto each other like hook-and-loop fasteners when the little device is closed and release when it opens. The whole system works on chemical changes the researchers make in the environment around the machine.

They say their work represents the first time such a macroscopic machine design approach has been used to form a complex DNA-based mechanism that performs a repeatable and reversible function. Their work was presented in a paper published Jan. 5 in the journal PNAS. “DNA origami enables the precise fabrication of nanoscale geometries,” the authors write. “We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements…Our results demonstrate programmable motion of 2-D and 3-D DNA origami mechanisms constructed following a macroscopic machine design approach.”

Read more about the work here.

“I’m pretty excited by this idea,” Castro said. “I do think we can ultimately build something like a Transformer system, though maybe not quite like in the movies. I think of it more as a nano-machine that can detect signals such as the binding of a biomolecule, process information based on those signals, and then respond accordingly—maybe by generating a force or changing shape.“

Gifs and image courtesy of Castro et al./The Ohio State University.