The robot is designed to be harmless and beneficial for aquatic fauna. EPFL
Most robots don’t end up as lunch, but these ones were built for it.
In a striking leap toward truly eco-friendly robotics, scientists in Switzerland have developed tiny aquatic robots that monitor water quality and are safe for fish to eat once their mission is over.
Shaped like miniature motorboats and powered by a gentle chemical reaction, these edible explorers are turning the idea of disposable tech into something far more sustainable — and surprisingly digestible.
Created by Professor Dario Floreano, PhD student Shuhang Zhang, and their team at Switzerland’s EPFL, each tiny, motorboat-shaped robot measures just 5 centimeters long and weighs about 1.43 grams. Despite their size, they’re surprisingly swift, gliding across water at up to three times their body length per second.
Fish feed with purpose
The secret lies in their construction and chemistry. The bots are built from ground-up fish feed pellets, molded and freeze-dried into shape.
Inside, a small chamber holds a harmless mix of citric acid and baking soda. This chamber is sealed with a gel plug and topped with a reservoir filled with non-toxic propylene glycol.
Once placed on water, the robot slowly draws in moisture through the semi-permeable plug. As the water comes in contact with the powder inside, a chemical reaction takes place that results in the release of carbon dioxide. The gas then pushes the glycol out through a tiny rear opening.
The expelled glycol alters the surface tension of the water through a natural propulsion trick known as the Marangoni effect, commonly used by insects like water striders. As a result of this effect, the robot gently scoots forward without the need for any batteries or motors.
The researchers envision releasing these tiny bots across ponds, lakes, or other water surfaces, where they’ll drift and dart around, collecting valuable data. Outfitted with sensors, the robots can measure things like water temperature, pH levels, or the presence of pollutants, transmitting the information wirelessly or storing it for later retrieval.
Eco bots, zero waste
But the real magic happens after their mission ends. As time passes, the hulls of these tiny robots absorb water, soften, and eventually sink. At that point, they become part of the food chain — literally. Fish or other aquatic animals can safely eat the bots, thanks to their entirely edible, non-toxic makeup.
RECOMMENDED ARTICLES
There’s also potential for a different kind of deployment: using the bots to distribute medicated feed in fish farms. Even if not consumed, all components are designed to fully biodegrade, leaving nothing harmful behind.
One challenge that remains is the sensors themselves. While the bot bodies disappear without a trace, making the electronics just as biodegradable, or even edible, is the next big step.
“The replacement of electronic waste with biodegradable materials is the subject of intensive study, but edible materials with targeted nutritional profiles and function have barely been considered, and open up a world of opportunities for human and animal health,” Floreano said.
The study was published in the journal Nature Communications.
0COMMENT
ABOUT THE AUTHOR
Neetika Walter With over a decade-long career in journalism, Neetika Walter has worked with The Economic Times, ANI, and Hindustan Times, covering politics, business, technology, and the clean energy sector. Passionate about contemporary culture, books, poetry, and storytelling, she brings depth and insight to her writing. When she isn’t chasing stories, she’s likely lost in a book or enjoying the company of her dogs.
MasterCard
