Russian experts in the field of nanoelectronics have created a working sensor prototype for determining the presence of mold and toxins in food products that it emits. The results are published in the journal Toxins . The study was supported by the Russian Science Foundation.
- Graphene Sensor Prototype
- © Ivan Bobrinetsky
Hazardous substances produced by molds are called ochratoxins. One of these toxins - ochratoxin A - does not break down even when heated or chemically treated, and is found everywhere - in cereals, fruits, and in raw materials for making wine, beer and coffee. Domestic researchers decided to find an effective way to prevent toxic moldy products from reaching store shelves and the dining table.
“The purpose of our study is to create a quick, simple and cheap sensor for detecting ochratoxin A in products at home ... One type of mold can produce several types of toxins. And in the future it is desirable to be able to determine all substances at once with one sensor. Manufacturing technology based on graphene just allows us to achieve this, ”said Ivan Bobrinetsky, project manager, leading researcher at the Moscow Institute of Electronic Technology.
As a basis for creating a prototype of the mold sensor and its toxins, the researchers used modified carbon - graphene. Researchers attached modified DNA sequences to the graphene lattice that selectively bind only ochratoxin molecules. Then, through the resulting device, they started up current. Upon contact with ochratoxin, the voltage changed - so scientists were able to determine the concentration of the harmful substance.
- Graphene-based sensor operation diagram. The sensor (in the center) binds to the ochratoxin A molecule (left). By changing the resistance (right), you can determine the concentration of toxin
- © Nekrasov et al. / Toxins, 2019
The sensor works with great accuracy - scientists were able to determine the presence of ochratoxin from 4 picograms per milliliter, which is almost a thousand times less than the maximum allowable content of this substance in food. Also, the new sensor was able to recognize the toxin, which as an experiment was artificially added to red wine.
“Selectivity was almost 100 times higher than that of other known graphene sensors. Also our sensor is reusable. We showed the possibility of recovery: we can rinse it and continue measuring, ”Bobrinsky summed up.
In the future, the authors plan to tackle the problem of determining bacterial toxins in fresh water and are exploring the possibility of developing complex sensors for the simultaneous determination of a large number of different substances.