|19 July 2016|

USA

A team of leading scientists in America are creating ‘biohybrid’ robots capable of crawling like sea turtles on the beach by combining tissues from a sea slug with flexible 3-D printed components.

The group from Case Western Reserve University are building the machines which could one day search the depths of fresh and saltwater. In the future, swarms of biohybrid robots could be released for such tasks as locating the source of a toxic leak in a pond that would send animals fleeing, the scientists say. Or they could search the ocean floor for a black box flight data recorder, a potentially long process that may leave current robots stilled with dead batteries.

“We’re building a living machine—a biohybrid robot that’s not completely organic—yet,” said Victoria Webster, a PhD student who is leading the research. Webster will discuss mining the sea slug for materials and constructing the hybrid, which is a little under two inches long, at the Living Machines conference in Edinburgh, Scotland, this week.

A muscle from the slug’s mouth provides the movement, which is currently controlled by an external electrical field. However, future iterations of the device will include ganglia, bundles of neurons and nerves that normally conduct signals to the muscle as the slug feeds, as an organic controller.

Webster worked with Roger Quinn, the Arthur P. Armington Professor of Engineering and director of Case Western Reserve’s Biologically Inspired Robotics Laboratory.

By combining materials from the California sea slug, Aplysia californica, with three-dimensional printed parts, “we’re creating a robot that can manage different tasks than an animal or a purely manmade robot could,” Quinn said.

The researchers chose the sea slug because the animal is durable down to its cells, withstanding substantial changes in temperature, salinity and more as Pacific Ocean tides shift its environment between deep water and shallow pools.

For the searching tasks, “we want the robots to be compliant, to interact with the environment,” Webster said. “One of the problems with traditional robotics, especially on the small scale, is that actuators—the units that provide movement—tend to be rigid.”

She continued: “Muscle cells are compliant and also carry their own fuel source—nutrients in the medium around them. Because they’re soft, they’re safer for operations than nuts-and-bolts actuators and have a much higher power-to-weight ratio.”

The team is preparing to test organic versions as well as new geometries for the body, designed to produce more efficient movement.

If completely organic robots prove workable, the researchers say, a swarm released at sea or in a pond or a remote piece of land, won’t be much of a worry if they can’t be recovered. They’re likely to be inexpensive and won’t pollute the location with metals and battery chemicals but be eaten or degrade into compost.