This squishy robot worm needs no batteries

Imagine a robot. But instead of sleek metal on wheels, with an elaborate blueprint of circuits and whirring gears, it’s a humble blob: a gelatinous lump stuck to the ground, which trudges around by squishing its body then elongating it again, inch by inch—like an inchworm—on its steady slog to anywhere.

That slug shows “a kind of intelligence,” says Johns Hopkins University. It’s actually the culmination of brilliant design, detailed by researchers in the journal of Science Robotics.

“It seems very simplistic, but this is an object moving without batteries, without wiring, without an external power supply of any kind—just on the swelling and shrinking of gel,” David Gracias, a professor of chemical and biomolecular engineering at Johns Hopkins University, and a leader of the team behind the slug, said in a statement. “Our study shows how the manipulation of shape, dimensions, and patterning of gels can tune morphology to embody a kind of intelligence for locomotion.”

It’s a breakthrough in the world of soft robotics, which is a fairly self-descriptive industry. While most robots are built from hard materials like metal or plastics, one of the most promising frontiers is the exploration of water-based gels that have the elastic bounce of gummy bears, which hold the potential to create more “human-like” robots. Such inventions could unlock new territory in the biomedical field.

Hopkins’s slug is powered by manipulating temperature fluctuations between 30 and 60 degrees Celsius, which can either swell or shrink its gel body (hot swells, cold shrinks). This way it can be strategically puppeted to move back and forth on flat and smooth surfaces like an inchworm, crawling here or there with a sort of undulating propulsion. The gelbots, as they’re called, are easy to manufacture—they were birthed from a 3D printer.

The scientists behind the study say they hope their gelbots are the first step (or squirm) toward refining soft robots for myriad purposes. Gracias envisions the slugs traveling along surfaces of organs and muscles within the human body to deliver targeted medicines. To this end, his next step will be to train them to crawl using human biomarkers as stimuli.

Hopkins researchers aren’t the first to draw inspiration from nature. Many scientists have discovered that natural forms and organisms are miraculous in their perfectly efficient patterns, honed over ages of evolution. And they surely won’t be the last to wonder what humans could learn from the earth.

In the meantime, they hope to keep going—to test other worm- or marine-life-mimicking structures, perhaps the next generation featuring sensors or cameras. In another of Gracias’s visions, robots inspired by aquatic organisms could serve as a self-sufficient ocean patrol, watching the water’s surface for signs of trouble.

But that future may still be far in the distance—and as with most world-changing ideas, they’ll have to take it inch by inch.