Edible Logic Circuits

As single-use and disposable electronic devices are becoming widespread for food and gastrointestinal tract monitoring, safe and sustainable materials development is emerging as a fundamental objective for technological innovation. The EU-funded ROBOFOOD project explores food-derived materials - an unprecedented and unconventional approach – to fabricate robots that could be metabolized (or degraded) in the body (or environment) after performing their function. In this perspective, the challenge consists of realizing stable edible electronic circuits that can provide synchronization, perform simple computation, and serve as memory, starting from notoriously unstable materials.<br/>Here we present the fabrication and characterization of edible logic circuits. For this aim, a printed edible electrolyte-gated transistor with a lateral gate configuration was fabricated using food-based inks. A comprehensive characterization was carried out revealing performance comparable with state of the art. Hence, edible logic gates operating at low voltage (&lt; 1 V) were demonstrated, integrating the transistor in unipolar configurations. Different edible materials and fabrication techniques compatible with the proposed transistor were also explored for implementing the required resistive load. Edible NOT and NAND gates were successfully fabricated and characterized using well-established metrics. More complex circuits, such as an edible ring oscillator working at a frequency around 1 Hz and a set/reset latch, were demonstrated. We believe that this work leads the way to edible logic circuits performing complex functions and to their integration into devices that can interact safely with humans and animals.