Scientists turn toothpaste into edible transistors for smart health tracking

It may surprise you to read this, but a substance found in our everyday toothpaste could be the key to edible electronics.

Researchers from the IIT-Italian Institute of Technology in Milan have now made a “toothpaste-based transistor” for healthcare.

The team says that this nano-device could be a vital component of “smart pills” in the future. Once within the body, the tiny device may track people’s health and then break down harmlessly.

“With the amount of copper phthalocyanine we ingest daily, we could theoretically manufacture approximately 10,000 edible transistors,” said Elena Feltri, the lead author and a doctoral student at the institute.

Teeth brightening pigment

The team focused on a substance called copper phthalocyanine. This blue pigment is commonly found in many commercial toothpastes and works as a whitening agent by coating the teeth with its crystals.

Interestingly, these crystals act as an “optical filter,” reflecting light in a way that makes the teeth appear whiter.

As the day goes on, the copper phthalocyanine is slowly removed by saliva and eventually enters your body.

Through research, they discovered that the average person unknowingly consumes one milligram of copper phthalocyanine every time they brush their teeth.

Interestingly, this pigment has a unique chemical structure. This allows for charge conduction within its crystals, meaning it can effectively carry electrical current.

This property makes it an ideal material for semiconductors, which are essential components in electronic devices. The pigment, being edible, could also power tiny electronic devices inside our bodies.

Various components

The researchers integrated small amounts of copper phthalocyanine into an edible circuit, creating a transistor that operates on a low voltage.

The circuits are built on a stable base of ethylcellulose substrate. It is often used in pharmaceutical and food manufacturing industries.

Furthermore, the electrical connections on the circuits were printed using inkjet technology. In this case, the ink contains a solution of gold particles. Gold is often used in food decoration as a pigment, and it’s also an excellent conductor of electricity.

All transistors consist of a “gate,” which regulates the flow of current.

The edible transistor’s gate was based on chitosan, a natural polymer derived from the shells of crustaceans like crabs. Chitosan is a “food-grade gelling agent,” making it safe for consumption.

When used to create an electrolytic gel, it forms a conductive material that can be used to control the flow of electricity.

By applying a low voltage (less than 1V) to the gate, it can control the flow of current through the transistor, effectively turning it on or off.

As per the press release , these edible transistors could be used in smart pills to monitor vital signs, detect diseases early, deliver targeted treatments, and even control food quality.

Next, the team plans to find other edible materials that have the right chemical and physical properties to create a smart, edible electronic device. These devices could be used for healthcare purposes, like monitoring body functions in the digestive system.

The findings were published in the journal Advanced Science.