Flame-Sprayed Nano-Sensor Can Warn of Harmful Pesticide Residue on Fruit in Just Five Minutes
Shelf-stable for months and produced at a low cost, these nano-sensors could help ensure the food you buy is safe to eat.
A term of researchers from the Karolinska Institutet in Sweden have developed a nano-scale sensor that, they say, is capable of detecting pesticides on fruit in mere minutes — and which is constructed using a dramatic-sounding flame-spraying process.
"Reports show that up to half of all fruits sold in the EU contain pesticide residues that in larger quantities have been linked to human health problems," says Georgios Sotiriou, corresponding author of the study revealing the new sensor. "However, current techniques for detecting pesticides on single products before consumption are restricted in practice by the high cost and cumbersome manufacturing of its sensors. To overcome this, we developed inexpensive and reproducible nano-sensors that could be used to monitor traces of fruit pesticides at, for example, the store."
The team's nano-sensor uses surface-enhanced Raman scattering (SERS), like many of its rivals — but unlike existing designs offers lower production costs, good stability, and high batch-to-batch reproducibility thanks to the adoption of a flame-spray approach to depositing silver nanoparticles onto a glass substrate. “The flame spray can be used to quickly produce uniform SERS films across large areas," first author Haipeng Li, postdoctoral researcher, explains, "removing one of the key barriers to scalability."
Experimentation with the sensors showed the design capable of reliable detection of parathion-ethyl, a toxic insecticide banned or restricted in many countries, even at low concentrations. "Our sensors can detect pesticide residues on apple surfaces in a short time of five minutes without destroying the fruit,” Li says. "While they need to be validated in larger studies, we offer a proof-of-concept practical application for food safety testing at scale before consumption."
In addition to further validation, the team is investigating other potential uses for the technology — including the discovery of biomarkers for specific diseases as a point-of-care diagnosis system.
The team's work has been published in the journal Advanced Science, and is available for early viewing under open-access terms.