Only the first freshness
A graphene sensor has been created to monitor the freshness and safety of products
Tatiana Matveeva, "Scientific Russia"
Researchers from the University of Iowa (USA) printed an electrochemical graphene sensor on a flexible polymer film, dipped it in tuna broth and observed the readings. The sensor was sensitive to histamine and allergens. It can also show the expiration date of food products, the press service of the university reports. The results of the study are published in the journal 2D Materials (Parate et al., Aerosol-jet-printed graphene electrochemical histamine sensors for food safety monitoring).
Histamine is a compound that is most often formed in fish and seafood. It accumulates in large quantities in these products when storage conditions are violated. Histamine in large quantities can cause headaches, diarrhea, and an allergic reaction in a person. Therefore, it is important to monitor its level in food. Different countries have different standards for the content of histamine in seafood: in the USA, for example, the maximum permissible value is 50 milligrams per kilogram (mg /kg), and in Russia – 100 mg/ kg.
The new sensor can detect histamine levels starting from 3.41 mg/kg. It is printed on a flexible polymer film by aerosol inkjet printing.
Why did the researchers choose graphene for their sensor? It is a material that is a carbon honeycomb with a thickness of only one atom and is known for its strength, electrical conductivity, flexibility and, importantly, biocompatibility. The decanter printing technology is an inexpensive procedure that is accurate enough to create high–resolution electrodes that are used in electrochemical sensors to detect small molecules such as histamine.
Graphene electrodes were printed on polymer and then converted into histamine sensors by chemically binding histamine antibodies to graphene. Antibodies specifically bind histamine molecules. According to the authors of the work, histamine blocks the transfer of electrons and increases electrical resistance. This change in resistance just measures and fixes the sensor.
Scientists believe that with the help of their technology, it is also possible to develop sensors that are sensitive to other types of molecules. Perhaps similar devices will be able to detect toxins in the environment, food pathogens, salmonella bacteria. As well as cancer or animal diseases, such as avian flu.
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