Swimming Toward Sustainability: The Rise of Edible Aquatic Robots
Imagine a robot that floats on water, propels itself forward without electronics, cleans up after itself, and can even be eaten by fish. Sounds like science fiction? Thanks to a pioneering study from researchers at EPFL and Wageningen University, it’s now a reality.
Their creation: a fully biodegradable, edible aquatic robot powered by the Marangoni effect—a natural phenomenon where liquids move due to surface tension gradients. This tiny robot could change how we approach environmental monitoring, aquatic health, and sustainable robotics.
What Is It, and How Does It Work?
The robot is about the size of a small snack—literally. Its boat-shaped body is made from freeze-dried fish food, molded with gelatin for structure. Inside, it contains a reservoir of propylene glycol (a safe, food-grade surfactant) and a reaction chamber filled with citric acid and baking soda.
When placed on water, the robot’s base absorbs water, triggering a chemical reaction that generates CO₂ gas. This gas pushes the surfactant out the back, creating a surface tension difference that propels the robot forward—no batteries, motors, or wires required.
Why It Matters: Robots That Leave No Trace
Conventional aquatic robots often rely on plastics and electronics, posing pollution risks if lost in the wild. These edible robots flip that paradigm:
- 100% biodegradable and non-toxic
- No electronic waste
- Can serve as food or medicine for aquatic animals once their task is complete
This makes them ideal for environmental sensing, aquafarming, or even fish enrichment in pet stores and labs.
Performance and Potential
The team conducted extensive tests in a water tank, showing that the robots could move at speeds comparable to living aquatic prey (up to 3 body lengths per second). They maintained motion for up to a minute and navigated in unpredictable, pseudo-random paths—potentially mimicking real prey behavior to engage predatory fish.
Not only can these robots move, but their nutritional profile is also customizable. They can deliver targeted nutrients or medications, opening the door to precision aquaculture or remote aquatic veterinary care.
Biodegradable Bots in Action: Future Applications
Here’s where edible aquatic robots could make waves:
- Environmental Monitoring: Swarms of edible bots could be equipped with biodegradable sensors to collect data on water quality, temperature, or pollution levels.
- Aquafarming: Replace static feed pellets with dynamic, motion-based delivery systems that stimulate natural hunting behaviors.
- Eco-Friendly Toys: For fish in pet stores or research facilities, these bots could provide enrichment and exercise, reducing stress and improving health.
- Search and Disperse: Deliver medicine or probiotics in hard-to-reach aquatic environments—then disappear harmlessly.
A Tasty Future for Robotics?
This study is a landmark step toward a new generation of "transient robots"—devices designed to perform, dissolve, and disappear. The edible aquatic robot represents a convergence of soft robotics, environmental science, and food engineering.
In a world facing rising pollution and growing demand for sustainable tech, these tiny edible swimmers offer a refreshing, forward-thinking solution. And while these bots may one day feed fish or monitor oceans, they also feed a broader vision: robotics that harmonize with the ecosystems they operate in, rather than disrupt them. They may be small, but their impact could be enormous—especially if they inspire a future where robots are not just tools, but nutrients too.
Check out the full publication for more information here:
- Shuhang Zhang, Bokeon Kwak, Ruihao Zhu, Markéta Pankhurst, Lu Zhang, Remko M. Boom, Dario Floreano. Edible aquatic robots with Marangoni propulsion. Nature Communications, 2025; 16 (1) DOI: 10.1038/s41467-025-59559-8
