Iowa State University scientists have developed graphene biosensors for monitoring food safety and livestock health.
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, these new biosensors can detect the same down to 3.41 parts per million.
According to the scientists, the aerosol-jet-printing technology was necessary to create the high-resolution electrodes for the electrochemical sensors to detect small molecules such as histamine.
“This fine resolution is important,” says one of the project leaders and associate professor Jonathan Claussen. “The closer we can print these electrode fingers, in general, the higher the sensitivity of these biosensors.”
Others involved in the project include Iowa State associate professor Carmen Gomes and Northwestern University professor Mark Jetsam.
According to the scientists, the graphene electrodes are first printed on a flexible polymer.
They are 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. That change in resistance can be measured and recorded by the sensor.
“This histamine sensor is not only for fish,” says Gomes. “Bacteria in food produce histamine. So it can be a good indicator of the shelf life of food.”
The researchers believe the concept can also work for other sensing applications such as environmental toxin detection, foodborne pathogen detection, wearable health monitoring, and health diagnostics.
Claussen, who has been working with printed graphene for years, says the sensors have another characteristic that makes them very useful: They don’t cost a lot of money and can be scaled up for mass production.
“Any food sensor has to be really cheap,” contend Gomes. “You have to test a lot of food samples and you can’t add a lot of cost.”
Image and content: Jonathan Claussen/Iowa State University