Nano-Scale Self-Assembling Nanotrain Controlled by DNA

Nano-scale technology is developing by leaps and bounds. Now, scientists have created tiny self-assembling transport networks, powered by nano-scale motors and controlled by DNA. The new system can construct its own network of tracks spanning tens of micrometers in length, transport cargo across the network and even dismantle the tracks.

While creating this new system, the researchers were inspired by melanophore, which is used by fish cells to control their color. Tracks in the network all come from a central point, like the spokes of a bicycle wheel. Motor proteins transport pigment around the network, either concentrating it in the center or spreading in throughout the network. Concentrating pigment in the center makes the cells lighter, as the surrounding space is left empty and transparent.

This new system works in a similar way. However, it's built from DNA and a motor protein called kinesin. Powered by ATP fuel, kinesins move long the micro-tracks carrying control modules made from short strands of DNA. The "assembler" nanobots are made with two kinesin proteins, which allow them to move tracks around to assemble the network, whereas the "shuttles" only need one kinesin protein to travel along the tracks.

"DNA is an excellent building block for constructing synthetic molecular systems, as we can program it to do whatever we need," said Adam Wollman, one of the researchers, in a news 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."

In this particular study, the researchers had the new "shuttle" system transport fluorescent green cargo which spread out across the track, covering it evenly. When they added more ATP, the shuttles all clustered in the center of the track where the spokes met. Then, the researchers sent signal shuttles along the tracks to tell the cargo-carrying shuttles to release the fluorescent cargo into the environment.

The study may have used fluorescent green dyes, but other compounds could be used as well. This new method could be used to speed up chemical reactions by bringing the necessary compounds together at the central hub. More broadly, using DNA to control motor proteins could enable the development of more sophisticated self-assembling systems for a wide variety of applications.

The findings are published in the journal Nature Nanotechnology.