An Electrically Conductive Oleogel Paste for Edible Electronics

Edible electronics will facilitate point-of-care testing through safe devices digested/degraded in the body/environment after performing a specific function. This technology, to thrive, requires a library of materials that are the basic building blocks for eatable platforms. Edible electrical conductors fabricated with green methods and at a large scale and composed of food derivatives, ingestible in large amounts without risk for human health are needed. Here, conductive pastes made with materials with a high tolerable upper intake limit (>= mg kg(-1) body weight per day) are proposed. Conductive oleogel composites, made with biodegradable and food-grade materials like natural waxes, oils, and activated carbon conductive fillers, are presented. The proposed pastes are compatible with manufacturing processes such as direct ink writing and thus are suitable for an industrial scale-up. These conductors are built without using solvents and with tunable electromechanical features and adhesion depending on the composition. They have antibacterial and hydrophobic properties so that they can be used in contact with food preventing contamination and preserving its organoleptic properties. As a proof-of-principle application, the edible conductive pastes are demonstrated to be effective edible contacts for food impedance analysis, to be integrated, for example, in smart fruit labels for ripening monitoring.

Automated summary

Edible electronics, which can be digested or degraded in the body or environment after performing specific functions, will enable point-of-care testing. To make this technology thrive, a library of materials is required as the basic building blocks of edible platforms. This study proposes edible conductive pastes made with green methods and food derivatives that can be ingested in large amounts without posing risks to human health. These conductive materials are compatible with industrial manufacturing processes and have tunable electromechanical features and adhesion.