Lausanne, Switzerland - May 08, 2025 Credit: LIS EPFL Scientists at EPFL have created an edible robot that glides across water using biodegradable fuel. This boat-shaped device offers a safe alternative to plastic environmental monitors. The robot uses the Marangoni effect, a phenomenon aquatic insects use to move. A chemical reaction with citric acid and sodium bicarbonate produces carbon dioxide, pushing out propylene glycol fuel. This lowers water surface tension, propelling the robot forward. This design is effective, allowing the robot to move for several minutes. It is also non-toxic and biodegradable, unlike typical robots that rely on plastics and batteries, which harm sensitive ecosystems. EPFL PhD student Shuhang Zhang says the team replaced harmful materials with edible components. The work, led by Dario Floreano in the Laboratory of Intelligent Systems, was published in Nature Communications. The 5 cm robot’s outer structure is made of fish food, with 30% more protein and 8% less fat than commercial pellets. This makes it nutritious for aquatic wildlife when it biodegrades, benefiting ecosystems. The team plans to deploy many robots with biodegradable sensors to monitor water pH, temperature, pollutants, and microorganisms. Data could be collected remotely or after retrieval. The robots have “left turning” or “right turning” designs for pseudo-random movement, mimicking insects. This makes them suitable for delivering nutrients or medication to fish, though no animal tests were done. This innovation advances edible robotics. The Laboratory of Intelligent Systems has explored edible actuators, fluidic circuits, and conductive ink. Floreano leads the RoboFood consortium, launched in 2021 with €3.5 million in EU funding. Floreano says edible materials with nutritional benefits are underexplored. They could open new possibilities for human and animal health, replacing electronic waste with biodegradable solutions.