Fully Edible Transistor: Towards Next Generation Edible Electronics

With the increased burden on healthcare workers in recent years, point-of-care medical devices for the gastro-intestinal tract that do not need external supervision (neither during ingestion nor for their retrieval) could be crucial for safe and early diagnosis, monitoring and treatment of many diseases. Edible electronics can enable such a vision through devices that are not only ingestible but are indeed digestible just like food, as they are made up of food-grade materials, thus zeroing the risks and health hazards posed by device retention and therefore the need for supervised administration. To turn this vision into reality, research efforts are steering towards functional edible electronic devices that can enable active signal monitoring and control of drug release inside the human body[1].<br/>In this work, we present a printed fully edible transistor operating at low voltage (&lt;1V). Inert metallic source-drain and gate staggered electrodes were inkjet-printed on top of an ethyl-cellulose edible substrate, while the chitosan solid electrolyte and the edible semiconductor Copper Phthalocyanine (CuPc) were drop-casted and thermally evaporated, respectively. The devices were characterized in terms of transport characteristics, air stability and reproducibility, showing performances comparable to conventional transistors based on the same semiconductor, an air stability of at least 12 months and a high degree of reproducibility. To realize a proof-of-principle logic gate, the transistor was connected with a commercial resistor to create an inverter. We believe that the results of this work can pave the way to the development of edible circuitry for a broad range of future applications in the medical, food and entertainment industry.<br/><br/><br/>[1] AS Sharova, F Melloni, G Lanzani, CJ Bettinger, M Caironi, “Edible electronics: The vision and the challenge” Advanced Materials Technologies 6 (2), 2000757