An Electrically Conductive Oleogel Paste for Edible Electronics

TL;DR

This paper introduces biodegradable, food-grade conductive oleogel pastes suitable for edible electronics, demonstrating their manufacturing, properties, and application in food impedance analysis for smart labels.

Contribution

It presents a novel edible conductive paste made from natural, food-safe materials with tunable properties, enabling large-scale production for edible electronic devices.

Findings

Effective in food impedance analysis

Compatible with direct ink writing processes

Possesses antibacterial and hydrophobic properties

Abstract

Edible electronics will facilitate point-of-care testing through safe and cheap devices that are digested or degraded in the body or environment after performing a specific function. Its thrive depends on creating a library of materials that are the basic building blocks for eatable technologies. Edible electrical conductors fabricated with green methods that allow production 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 (major of mg/kg body weight /day) are proposed. Conductive oleogel paste 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 the use of 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.