This robot is edible, including the battery

When it comes to robots, who doesn't wonder whether they are edible? Until recently, probably nobody, but the topic of fully edible robots is clearly becoming increasingly important. Swiss scientists have now developed a soft robot that can be chewed and swallowed whole, battery and actuators included.

Like non-edible soft robots, this one can move using a system of pumps. Typically, soft, swallowable actuators that operate using gas pressure and therefore require pumps cannot be manufactured without plastic and metal. However, in this case, materials such as wax and gelatine were used — even the tubes for the pumps are made of gelatine.

How is the edible robot built?

The team at the Intelligent Systems Laboratory from EPFL University, led by Dario Floreano, has also found a way to make the power supply elements edible - as part of the EU-funded RoboFood project. A soft robot usually moves by pumping air into and out of the chambers of its body, causing deformation and generating movement. In this case, separate containers holding baking soda and liquid citric acid are used to store chemical energy, and carbon dioxide is pumped into the chambers as a propellant.

A membrane made of baking soda ensures proper separation. The battery is activated by applying pressure to the membrane of the acid chamber. Once the pressure is high enough, the acid breaks through the membrane and mixes with the baking soda, triggering a simple acid-base reaction. This reaction releases carbon dioxide (CO₂) and sodium citrate, a substance commonly used in the food industry and considered harmless.

Scenarios in which the edible robot could be used:

The original idea behind edible robots was to administer medication to animals such as wild boars, which people tend to want to avoid getting too close to. Since these robots are cheap, biodegradable, safe to transport, mobile and resemble prey, they could be useful in administering vaccines in cases of swine flu or other diseases.

However, trials on humans are also currently underway. For instance, fruit-flavoured actuators were handed out to people at the start of the year, and feedback is now being analysed. In addition to basic measurability, factors such as sustainability also play a role in robotics. Project manager Dario Floreano explains: 

If you look at it from the broader perspective of environmental and sustainable robotics, the pneumatic battery and valve system is a key enabling technology, because it’s compatible with all sorts of biodegradable pneumatic robots.