Sea slug biohybrid robot could search ocean floor

The ‘biohybrid’ robots, which are less than two inches long, are able to crawl slowly in a movement similar to a sea turtle on the beach. According to the researchers, swarms of the bots could someday be used to find black box flight recorders at sea, or toxic leaks in ponds or lakes.

“We're building a living machine - a biohybrid robot that's not completely organic - yet," said Victoria Webster, a PhD student at Case Western and the research lead.

The team chose the sea slug for the durability of its tissue, and adaptability in any environment. Movement of the robot is provided by the buccal muscle from around the sea slug’s mouth. Combining this with a 3D printed exoskeleton, the researchers were able to make the robots crawl using an external electrical field.

Further down the line it’s hoped that collagen from the slug’s skin can be used to provide an organic scaffolding structure, and that an element of the animal’s own nervous system, called the ganglia, could be used to induce movement. This would provide a fully organic robot that could be controlled by either chemical or electrical stimuli.

"With the ganglia, the muscle is capable of much more complex movement, compared to using a manmade control, and it's capable of learning," Webster said.  "We want the robots to be compliant, to interact with the environment."

The plan is to train the ganglia to react to signals that would move the robots forward and backward. Early tests on the bots saw them crawling about 0.4cm per minute, but the team is working on new geometries for the body that would deliver more efficient movement. If an entirely organic bot can be achieved at a low cost, the researchers believe that swarms could be released at sea without the need to recover them.