Nerve-Like Polymer Structure Could Lead To New Prosthetics Interface

Scientists from Sandia National Laboratories, a subsidiary of defense giant Lockheed Martin, have created a set of polymer nanotubes that resembles the structure of a nerve, possibly producing a new method of interface between machines and the nervous system.

"This is the first demonstration of naturally occurring proteins assembling chemically created polymers into complex structures that modern machinery can't duplicate," Sandia National Laboratories researcher George Bachand said Monday in a press release.

Current prosthetics use rigid electrodes to penetrate the nerve tissue, but these can often cause inflammation, necrosis and other skin conditions. The researchers’ polymer network could be used as an organic extension of the nervous system, creating a less intrusive interface.

"This is foundational science, but one possibility we see, way down the road, is to use soft artificial structures like these to painlessly interface with the body's nerve structures." Sandia co-researcher Wally Paxton said.

The delicate and complex neural structure of these polymers cannot be created through normal means. Instead, the team began by altering kinesin motor proteins, which are responsible for carrying material between cells. These kinesins were glued to a glass substrate, holding them in place while also continuing their movement. The microtubules are then passed along above them, allowing the structures to travel.

These microtubules, pre-coated with a sticky substance, encountered larger polymer spheres. The microtubules then pinched off polymer nanotubes from the sphere, which went on to stretch and grow longer as the microtubules continue moving forward. As the nanotubes become longer and more complex, they form interconnected, networked structures.

"One goal of our work is to make an artificial, highly branched neural structure," Bachand said. "The next step is, can we wire them together? The answer is, the motors should do it naturally. And two such networks, joined together, would have self-healing built into them. The motors never stop running until they run out of fuel. A neural branch breaks, and then a motor can act on that area to produce a new branch."

The results of their research were published in April in the journal Nanoscale. The scientists said that the structure was also found to be able to transmit light and electricity through it, opening the way for applications in electronics and communication.