Nanotrain Network Assembles Tracks, Transports Good and Cleans Up Behind Itself

Researchers have developed tiny transport networks that construct their own tracks just tens of micrometers long, transporting cargo across the tracks and even picking up behind themselves by dismantling the tracks.

Published in the journal Nature Nanotechnology, the study was inspired by melanophore, which fish cells use to control their color. In melanophore, motor proteins transport pigment around the network. By concentrating pigment in the center, the cells become lighter as the remaining region is left empty and, as a result, transparent.

The new system is powered by ATP fuel, and consists of motor proteins known as kinesins traveling along micro-tracks carrying modules constructed from short DNA strands.

"DNA is an excellent building block for constructing synthetic molecular systems, as we can program it to do whatever we need," Adam Wollman, who conducted the research at Oxford University's Department of Physics, said in a press release. "We design the chemical structures of the DNA strands to control how they interact with each other. The shuttles can be used to either carry cargo or deliver signals to tell other shuttles what to do."

The shuttles only require one kinesin protein to shuttle it along the tracks, whereas the "assemblar" nanobots, which scurry around to assemble the network, require two.

"We first use assemblers to arrange the track into 'spokes', triggered by the introduction of ATP," Wollman said. "We then send in shuttles with fluorescent green cargo which spread out across the track, covering it evenly. When we add more ATP, the shuttles all cluster in the centre of the track where the spokes meet.

"Next, we send signal shuttles along the tracks to tell the cargo-carrying shuttles to release the fluorescent cargo into the environment, where it disperses. We can also send shuttles programmed with 'dismantle' signals to the central hub, telling the tracks to break up.'

Though the study uses fluorescent green dyes as cargo, the method could be used with a wide range of compounds, the researchers note.

"More broadly," the press release outlining the study explains, "using DNA to control motor proteins could enable the development of more sophisticated self-assembling systems for a wide variety of applications."

To see the network in action, click here.