Forget batteries: tiny, wriggly robot runs on moisture

Forget batteries and electricity — the tiny robots of the future could run on moisture.

Researchers at Seoul National University in South Korea, have created robots that can “inchworm” forward by absorbing humidity from their surrounding environment. The so-called hygrobots, described this week in the journal Science Robotics, can crawl, wriggle back and forth, and twist like a snake. And in the future, they could be used for a variety of applications, including delivering drugs to human skin, The Verge reports.

The inspiration for the tiny bots came from plants, which can change shape and size by absorbing water from the ground or air (called hygroexpansion). For instance, pine cones close when it’s wet, and open when it’s dry so that the seeds inside them can disperse farther away. Plants have inspired robots before: last year, for instance, researchers made robots out of algae.

The robots in question aren’t made of plant material; they just mimic the mechanisms behind plants. Making a robot that runs on moisture is valuable because moisture is an all-natural source of power. It’s also not toxic, unlike batteries, which can and do explode. That’s key for microrobots that need to be used inside the human body.