"My lab has built a versatile sensing platform that incorporates all the needed reagents for detection in a piece of paper. At the same time, it is adaptable to different targets, including food contaminants, antioxidants and free radicals that indicate spoilage,” Dr Silvana Andreescu, the lead scientist behind the development, explained.
Dr Andreescu, who works at Clarkson University, said that the work reflects her interest in technologies that “are accessible to both industry and the general population".
What makes Dr Andreescu's sensors unique, she claimed, are the nanostructures they use to catch and bind to compounds they're looking for.
"Most people working on similar sensors use solutions that migrate on channels," she said. "We use stable, inorganic particles that are redox active. When they interact with the substances we want to detect, they change colour, and the intensity of the change tells us how concentrated the analyte is."
Because all of the reagents needed to operate the device are incorporated in the paper, users don't need to add anything other than the sample being tested.
Fighting food fraud, contamination and waste
The research team said that the potential applications for the tech are “wide-ranging”.
Much of the sensor work to date has focused on detecting antioxidants in tea and wine. Dr Andreescu and her team found these products have unique antioxidant “fingerprints” that can be used for authentication purposes to combat food fraud.
The researchers have also extended their work to look at food contamination and environmental pollutants. One sensor prototype can spot ochratoxin A, a fungal toxin commonly found in a range of products, including cereals and coffee. She noted this direction could be expanded further to look for salmonella and E. coli.
Dr Andreescu's next focus is the development of paper-based devices that change colour when food spoils. These sensors bind to the reactive oxygen species that products accumulate as they age and eventually go bad. Although testing for this application is still ongoing, Dr Andreescu said this technology could one day be incorporated into smart labels that would tell consumers when to throw a product out.
Combatting food waste is an important issue as the food sector looks to develop more sustainable models and ensure production will be sufficient to feed the world’s growing population, which is forecast to hit 9bn by 2050. According to the Food and Agriculture Organization of the United Nations, 30% of the world’s cereals, 20% of dairy, 35% of seafood and 20% of meat is currently wasted.
The researchers will present their results today at the National Meeting & Exposition of the American Chemical Society (ACS).