Recently, it was reported that a research team at the Institute of Technology (IIT) in Italy has made a breakthrough in the field of edible electronic devices, developing a new transistor based on a common ingredient in toothpaste. This innovation is expected to drive the development of smart pill technology, which is able to monitor the health status of the human body and safely break it down after completing the task.
Copper phthalocyanine crystals, a blue pigment commonly found in toothpaste, are commonly used to whiten teeth. This pigment is deposited on the teeth during toothbrushing, and over time, saliva gradually removes it so that it can be ingested into the body. IIT's Center for Nanoscience and Technology (CNST), in collaboration with dental experts at the University of Novi Sad in Serbia, studied the properties of copper phthalocyanine and found that we consume about 1 mg of copper phthalocyanine on average when brushing our teeth every day.
The study's lead author, Elena Feltri, a PhD student at the IIT CNST, noted that it is theoretically possible to make about 10,000 edible transistors based on the amount of copper phthalocyanine we consume each day.
The chemical structure of copper phthalocyanine makes it ideal for semiconductors in organic electronics applications as it favors the conduction of charge in crystals. The research team used the pigment as a semiconductor and integrated it into the edible circuit formulations they had already tested. The circuits are built on ethylcellulose substrates, electrical contacts are printed using inkjet technology, and a gold particle solution is added, which is commonly used for culinary decoration. The "gate" of the transistor is made of an electrolytic gel based on chitosan, which is a food-grade gelling agent extracted from crustaceans, enabling the transistor to operate at low voltages below 1V.
Picture: Swallowable smart pills (Source: UC San Diego School of Engineering)
The research was carried out in the Printing and Molecular Electronics Laboratory led by Mario Caironi. Last year, the team invented edible batteries. Caironi's laboratory is focused on exploring the electronic properties of food and its derivatives to develop edible electronic devices for future healthcare and food quality control. In 2019, Cairani received a grant of 2 million euros from the European Research Council for the ELFO project, which explores the field of food electronics. Since 2021, his team has also been involved in the European RoboFood project, which aims to develop edible robots.
Edible transistors are used in a wide range of applications and have great potential. For example, food transistors can be used as a key component of smart pills for in vivo health monitoring and drug delivery. These pills allow for a physical condition check as well as drug release within the digestive tract, helping to better diagnose conditions, remote patient monitoring, and targeted drug delivery. Another example is that edible electronic devices can be used to monitor bodily parameters in the gastrointestinal tract, for example, to develop digestible sensors to help treat or monitor intestinal diseases. In addition, it can also be used to locate missing people or objects, transport important food or medicine for emergency rescue, etc.
The next step for the research team is to find other edible substances with appropriate chemical and physical properties to make smart edible electronic devices for healthcare applications, such as monitoring bodily parameters within the gastrointestinal tract.
