Scientists developed a biosensor that allows to control the quality of wine

Russian scientists, together with foreign colleagues, have developed a biosensor based on graphene and nucleic chains to detect mold toxins in wine. Ultra-high sensitivity and speed of the device makes it an excellent alternative to expensive and complex classical methods and a record holder among sensors in its class. The results of the work were published in Biosensors & Bioelectronics journal.

One shouldn't eat a product affected by mold, even if the spoiled part is removed: by this time the mycelium of the fungi has already penetrated throughout the product and spread mycotoxins that are dangerous to human and animal health. This problem is also applicable to wine. If the wort was infected with a fungus, a drink made from it can be seriously poisonous.

It is important to monitor the presence of mycotoxins in wine before it is on sale. “For these purposes, specialists traditionally use high-performance liquid chromatography-mass spectrometry and enzyme immunoassay,” said Ivan Bobrinetsky, Doctor of Technical Sciences, Leading Researcher at the Scientific and Educational Center "Probe Microscopy and Nanotechnologies" of MIET.

Ivan continued: “These are high-precision methods, but quite laborious and requiring the involvement of a specialist. Wine produced at large wineries is constantly tested, but home winemakers may not have access to control equipment. We have proposed an easy-to-use, fast and record sensitive biosensor for the detection of mycotoxins”.

Scientists from MIET and Institute of General Physics of the Russian Academy of Sciences, together with Serbian and American colleagues, presented a biosensor based on graphene field-effect transistors and aptamers — short DNA chains. These chains specifically bind to the most common mycotoxin, ochratoxin A, which is produced by molds from the Aspergillus and Penicillium genus.

When ingested, this substance disrupts the functioning of the nervous and immune systems, kidneys, liver, and can cause the development of cancerous tumors. Its great danger is that it cannot be neutralized either by chemical treatment or by heating.

The sensor is a silicon wafer with metal tracks. A layer of graphene was transferred to them, and aptamers were chemically “attached” on it. The operation principle of the biosensor is based on the fact that aptamers, when bound to ochratoxin, change their configuration (similar to coiling in a DNA chain). This is enough to affect the number of traveling electrons in graphene. As a result, the electrical properties of the material change, which can be seen using special measuring instruments connected to the biosensor. The higher the concentration of the analyte in the sample, the stronger the signal.

The chips were packaged in tiny containers where one can pour the sample - a drop is enough. The authors tested the development on red and white wine previously contaminated with ochratoxin A. Biosensors were able to detect record low concentrations of a substance - trillionths of moles per liter. The signal appears in less than a minute, and in some cases - in 10 seconds.

“Our biosensors have shown record speed and accuracy in detecting ochratoxin A compared to other existing devices. Sample preparation is as simple as possible, calibration is not required, and chip cleaning is not difficult. The developed biosensor contains 30 graphene sensors. The set of aptamers can be expanded to identify more compounds dangerous to humans at a time,” concluded Ivan Bobrinetsky.

The study was supported by grants from the Russian Science Foundation (RSCF).