Researchers Develop Tune Graphene Sensors to Monitor Food Freshness, Safety

Monday, June 29, 2020 - 10:14

Researchers of Iowa State University have printed sensors which can monitor food freshness and safety.

It turned out the sensors - printed with high-resolution aerosol jet printers on a flexible polymer film and tuned to test for histamine, an allergen and indicator of spoiled fish and meat - can detect histamine down to 3.41 parts per million, Eurek Alert reports.

Making the sensor technology possible is graphene, a supermaterial that's a carbon honeycomb just an atom thick and known for its strength, electrical conductivity, flexibility and biocompatibility. Making graphene practical on a disposable food-safety sensor is a low-cost, aerosol-jet-printing technology that's precise enough to create the high-resolution electrodes necessary for electrochemical sensors to detect small molecules such as histamine.

"This fine resolution is important," said Jonathan Claussen, an associate professor of mechanical engineering at Iowa State University and one of the leaders of the research project. "The closer we can print these electrode fingers, in general, the higher the sensitivity of these biosensors."

Claussen and the other project leaders - Carmen Gomes, an associate professor of mechanical engineering at Iowa State; and Mark Hersam, the Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University in Evanston, Illinois - have recently reported their sensor discovery in a paper published online by the journal 2D Materials.

The paper describes how graphene electrodes were aerosol jet printed on a flexible polymer and then converted to histamine sensors by chemically binding histamine antibodies to the graphene. The antibodies specifically bind histamine molecules.

The histamine blocks electron transfer and increases electrical resistance, Gomes said. That change in resistance can be measured and recorded by the sensor.

"This histamine sensor is not only for fish," Gomes said. "Bacteria in food produce histamine. So it can be a good indicator of the shelf life of food."

The researchers believe the concept will work to detect other kinds of molecules, too.

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