Edible Electronics and Robofood: A Move Towards Sensors for Edible Robots and Robotic Food

Sustainability remains an underdeveloped aspect when designing an electronic device, even though technology is more pervasive in our society. As such, a paradigm change is needed toward the use of more environmentally friendly materials and processes. Edible electronics proposes integrating food-grade materials into more complex system such as robots, thus contributing to reducing e-waste accumulation. Besides sustainability, biocompatibility, and biodegradability, the use of food-grade materials in electronics has unprecedented advantages including minimal toxicity levels, especially in case of ingestion. Thus, edible electronics and robotics opens unprecedented scenarios: in the future rescue drones could integrate edible components, effectively increasing the food payload of the mission; robotic food could be employed as drug delivery vectors for wild animals; ultimately, miniaturized edible robots could enable novel diagnostic tools that can be digested by the body after performing a specific test. The EU-funded “Robofood” project works towards this vision. In this frame, we present a versatile fully edible electrically conductive ink for edible electronics and robotics. The ink is based on activated carbon - an organic edible electronic conductor with a daily intake up to three orders of magnitude higher than metals - and is formulated to be deposited by spray coating. Successful deposition on different edible substrates was obtained. As a proof-of-principle for the use of this material in edible robotics, a first application for bending sensing is herein reported. The coating was interfaced with a standard microcontroller and data was recorded during finger bending. The materials and methods developed in this work have a high degree of versatility and could be applied to other scenarios. We believe that the vision supported by this project has the potential to open the way for novel edible technologies for applications such as medicine and food quality monitoring among others.