Ellen Phiddian
Cosmos science journalist
Researchers have made an edible transistor out of a toothpaste ingredient.
They say their transistor could one day be used in edible electronics which help to monitor and treat diseases.
The Italian and Serbian research team has published its findings in Advanced Science.
The transistor is made from copper phthalocyanine, a whitening agent commonly used in toothpastes.
While copper phthalocyanine is not currently approved for use in foods, there is a body of evidence from clinical trials showing it’s safe in toothpaste, and there haven’t been any recorded reactions to it after being used in toothpaste for more than a decade.
The researchers added to this by running tests to see how much copper phthalocyanine the average tooth-brusher ingests every time they brush their teeth.
The answer was about 1 milligram per brushing.
“With the amount of copper phthalocyanine we ingest daily, we could theoretically manufacture approximately 10,000 edible transistors,” says lead author Elena Feltri, a doctoral student at the the Istituto Italiano di Tecnologia.
Copper phthalocyanine can also be used as a semiconductor, the key property needed for a transistor.
The researchers tested copper phthalocyanine in an edible circuit they’d previously built, made from ethylcellulose (a derivative of cellulose), gold particles, and chitosan (a gelling agent taken from crustaceans).
The circuit was made by inkjet printing and depositing layers of each substance on top of one another.
It could operate stably at a low voltage, less than 1 volt, for more than a year.
The team, which has previously made an edible battery with these techniques, is now investigating the electronic properties of other foods.
