Scientists and chefs work together to create a robot wedding cake that can be eaten all. Image source: EPFL

　　Imagine a future picture like this: the water robot turns into bait for koi to peck at the koi, the robot turns into a delicious cake after dancing... These technological concepts that are full of creativity and fireworks are now entering reality.

　　The research team of the Federal Institute of Technology of Lausanne (EPFL) in Switzerland uses fish feed as raw materials to create a water robot. After completing the mission, it will turn into a delicious meal for fish, which will naturally degrade. Previously, scientists at the school also worked with Italian scientists to launch a fully edible robot wedding cake, RoboCake.

　　Edible robots not only help cleverly resolve the pollution problems of traditional electronic equipment, but are also opening the door to innovation in multiple fields, and are expected to show their skills in health care, environmental management, etc.

　　It's both a tool and a food

　　In the EPFL intelligent system laboratory, the water robot created by Professor Dario Floriano's team is like a miniature jet ski, with an average weight of 1.43 grams, and can move as fast as 3 times the length per second in the water.

　　The secret of this robot is its unique construction. The main structure is composed of lyophilized fish feed, and the power comes from a chemical reaction triggered by water: citric acid reacts with sodium bicarbonate to produce carbon dioxide, and the gas pressure forces propylene glycol to eject, causing a sudden drop in the local water surface tension to form thrust, which can push the robot to move continuously for several minutes.

　　And all components of the robot are biodegradable. Researchers said that when the robot completes the task, it will absorb water and soften like soaked tea leaves, slowly sink into the water, becoming a delicious meal for fish.

　　The "RoboFood" project led by Floriano was launched in 2021 to build edible robots for food preservation, emergency nutritional replenishment, human and veterinary medicine, and has received 3.5 million euros in the EU. The laboratory has developed a number of innovative achievements, such as edible fluid circuits, edible conductive inks used to monitor crop growth, etc.

　　The latest masterpiece of "Machine Food" is RoboCake. The top of this three-layer wedding cake is decorated with a pomegranate-flavored gelatin fudge robot that moves the head and arms with the help of a pneumatic system; the bottom layer is embedded with an edible battery made of vitamin B2, quercetin and chocolate to power LED candles.

　　Floriano said they are redefining the boundaries between robots and food, and future robots may be both tools and food.

　　Widely used to facilitate environmental protection

　　Floriano believes that the aquatic robot developed by his team not only provides new ideas for environmental monitoring, but also innovates the aquaculture industry's drug administration methods.

　　The application of water robots is just the tip of the iceberg. EPFL scientists have written in the journal Nature Review Materials that edible robots are expected to play a role in health care, environmental regulation and other fields.

　　Edible robots enable precise drug delivery and in vivo health monitoring. Specifically, it can deliver medications along the esophagus, help people or animals with dysphagia, reduce the risk of inhaled pneumonia, or monitor health status in real time in the digestive tract.

　　Edible robots can also provide nutrition to humans or animals in emergencies. For example, it is particularly suitable for wildlife rescue because animals have a natural interest in mobile food sources. In aquaculture, this characteristic can improve feed utilization and reduce water pollution.

　　At the same time, the mobile edible robot can simulate the food that wild animals love, with a built-in vaccine and positioning system, and actively attract wild animals such as wild boars to be vaccinated to effectively control the spread of the disease.

　　In addition, edible robots can also provide people with a novel food experience. For example, RoboCake's first bite is a rich dark chocolate flavor, which will then make people feel the slightly acidic stimulation of the electrolytes. This "flavored cake" shows the infinite possibilities of food technology.

　　Most importantly, in the context of 40 million tons of electronic waste generated every year around the world, the design concept of edible robots, "come from nature and go back to nature" is redefining the harmonious relationship between technology and the environment.

　　Risk challenges still need attention

　　While edible robots are developing rapidly, scientists are carefully considering their potential risks and challenges.

　　First of all, it is the problem of intelligent computing. The existing computing systems rely on traditional transistors and are inedible; although biomolecules such as carotenoids and edible dyes are edible, their information processing and integration capabilities are limited. How to build a computing system that is both intelligent and digestible is still a major issue.

　　Another big challenge is the lack of verification of the safety of edible robots. Although their materials are digestible and considered safe, some scientists are concerned that while some edible robot ingredients are safe to eat alone, cross-reacting of multiple ingredients may lead to unforeseen adverse consequences.

　　Miniaturization and quality control are also problems that need to be solved by edible robots. If these robots are designed to evaluate body functions and perform medical interventions autonomously (such as precise administration), their volume must be small enough. Furthermore, unlike relatively simple, pure nutrition robots, this robot consists of more components and must work together, and any failure can lead to catastrophic consequences. Therefore, quality control must be carried out to ensure that it operates in the body without any mistakes.

　　In addition, Floriano's team also pointed out that extending the shelf life of edible robots and giving them a pleasant taste is also a difficult problem that needs to be solved. (Reporter Liu Xia)

[Editor in charge: Ran Xiaoning]