New underwater robot is powered by sea slug muscle

The "biohybrid" robot. (Andrew Horchler)

Last month, scientists unveiled a tiny robot that swims using rat heart cells. Now, researchers from Case Western Reserve University have revealed a “biohybrid” robot of their own, except this one runs on slug. The robot was constructed from a harvested sea slug mouth muscle and a two–inch 3–D printed skeleton. When given electric shocks, the bot springs to life and crawls.

The tiny muscle belongs to the Aplysia californica, a durable California sea slug also known as a sea hare. To survive in the Pacific, the slug’s muscles have to be able to handle substantial temperature and salinity changes, making them an ideal candidate to become part of an underwater robot.

That’s not say to the slimy sea hares were the first choice.

“We did early work using chick embryos,” Roger Quinn, director of Case Western Reserve’s Biologically Inspired Robotics Laboratory, told FoxNews.com. “[But] the sea slug is a better candidate because it is robust at a wide range of temperatures, [and] there is a great deal known about its biomechanics and its relatively simple nervous system. Also, many of the missions we foresee are in seawater, the sea slugs’ habitat.”

Initially the team attempted to use muscle cells only, but soon switched to using the entire buccal muscle due to its excellent form and structure. After the tiny muscle’s two “arms” are glued to a 3D-printed polymer frame, the muscle is controlled by an external electric field, making it contract. This contracting and releasing enables the robot to crawl like a sea turtle at a rate of 0.5 centimeters per minute. For future versions, Quinn and his team plan to use parts of the slug’s nervous system (ganglia, bundles of neurons and nerves that send signals to the muscle while the slug feeds) as an organic controller, which they expect will be adaptive and flexible.

Being durable and adaptable in a harsh environment gives these biohybrid bots the edge over traditional robotic equipment, which is more vulnerable to the elements. Also, if it does break down, a biohybrid model doesn’t become another piece of metal junking up the scenery at the bottom of the ocean.

“Unlike most man-made materials, natural materials decompose quickly and feed other animals and plants,” Quinn said.

This isn’t the Six Million Dollar Slug we’re talking about here– the robots will ultimately be cheap to produce. The hope is to someday deploy swarms into oceans, lakes, and rivers to detect toxic leaks. They could also scour the ocean floor for lost black box flight data recorders, a long process that leaves current robots rusting away in Davy Jones’ locker due to dead batteries.

So when can we expect to see Roboslug hit the underwater streets?

According to Quinn, with adequate resources for development, it’s probably three to five years off.

“There is a great deal of research needed before these robots can be deployed,” he said. “We plan to develop more efficient designs, make better use of the animal's muscle, incorporate sensors into the robot and to make use of the animal's nervous system for control of autonomous movement.”