'Walking' DNA motor on nanotube tracks could someday deliver drugs

Illustration of a synthetic DNA molecule "walking" along the surface of a nanotube.--Courtesy of Purdue

Inspired by natural biological "motors" made of protein, researchers at Purdue University have developed a DNA-based molecule that can "walk" across the surface of nanotubes, potentially carrying nanomeds with it for the purpose of drug delivery.

In living cells, protein-based motors transport cargo by inching along tubes within the cell, according to the team's abstract in the journal Nature Nanotechnology. By changing its shape and binding to consecutive parts of the tube's surface, these natural molecules are able to travel as far as a micrometer (1,000 nanometers) by taking steps of 8 nanometers at a time.

Mimicking this complex process, the Purdue team developed a molecule with a core and two DNA arms, according to a university report. Using strands of RNA, the molecule moves from one to the next across the surface, like Tarzan using vines to swing through the jungle. Each strand gives the molecule energy to keep moving forward.

"Our motors extract chemical energy from RNA molecules decorated on the nanotubes and use that energy to fuel autonomous walking along the carbon nanotube track," lead researcher Jong Hyun Choi said in a statement. "We are in the very early stages of developing these kinds of synthetic molecular motors."

To test the motors' transport ability, the team had them carry nano-sized cadmium disulfide across a nanotube. It took 20 hours for the motor to make it only a few microns, which is much slower than the natural motors, but the concept could someday be a useful way to control drug transport within cells.

- here's the Purdue University report
- and here's the study abstract