A multidisciplinary Brazilian research team has developed a biosensor to measure pesticide content on food produce, water and soil. The technology is in its development phase, but if developed into a commercial product it could provide a cheap, affordable and portable method to monitor this type of contamination.

The biosensor is the result of a research carried out by Izabela Gutierrez de Arruda, a post-graduation student at Instituto de Física de São Carlos (IFSC), in São Paulo State. The biosensor uses an enzyme inhibitor to detect the presence of a pesticide called methamidophos, an insecticide linked to neurological problems. Although enzyme inhibition is not necessarily a new method, the innovation here is in the use of an ultra-thin film to magnify the signals.

The researchers used an enzyme called acetylcholinesterase, which also occurs in the human brain. It works with the neurotransmitter acetylcholine, which is involved in cognitive functions such as thought and memory. When it comes into contact with the molecules of the methamidophos insecticide, its action is inhibited and it will produce fewer protons in comparison with an enzyme that is not exposed to the same substance. The difference in proton numbers is displayed in a small device where the film had been introduced, showing the levels of contamination.

“The device will look like one of those used to measure glucose levels,” Gutierrez tells Gizmag. “Because of its small size, farmers could carry out measurements themselves and get instant results. Current methods usually use chromatography and spectrometry, which require technical expertise and expensive equipment, besides the fact that the measurements are not produced instantly.”

The development of the biosensor was inspired by the health issues related to the overuse of methamidophos, in particular in Gutierrez’s native state of Mato Grosso, Brazil’s largest grain producer. Even though this pesticide is banned in several countries, including the whole of the European Union, its use is widespread in Mato Grosso, threatening groundwater with chemical pollution.

Among the neurological problems it can cause are memory loss, anxiety, mental confusion, and, according to the scientists, there is the possibility that it could also increase chances of developing Alzheimer's.

The researchers point out that since the biosensor is still in the research phase, it could be adjusted to signal other types of insecticides in the organophosphate and carbamate categories. The project kicked off in 2011 and a patent has already been filed. The next step is to find a company that would be interested in developing the biosensor into a commercial product, which they expect would cost between R$100 (US$46) and R$200 (US$92).

Gutierrez has worked under the supervision of Dr. Romildo Jerônimo Ramos (Universidade Federal do Mato Grosso - UFMT), co-supervision of Dr. Nirton Vristi Silva Viera (IFSC). Professor Francisco Eduardo Gontijo Guimarães (IFSC) also collaborated to the research, which was carried out in partnership with UFMT’s Instituto de Física.

Source: IFSC

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