Nano-sensor detects pesticides on fruit in minutes

Researchers at Karolinska Institutet in Sweden have developed a tiny sensor for detecting pesticides on fruit in just a few minutes.

The technique uses flame-sprayed nanoparticles made from silver to increase the signal of chemicals. While still at an early stage, the researchers hope these nano-sensors could help uncover food pesticides before consumption.

"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, principal researcher at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, and the study's corresponding author.

"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 new nano-sensors employ a 1970s discovery known as surface-enhanced Raman scattering, or SERS, a powerful sensing technique that can increase the diagnostic signals of biomolecules on metal surfaces by more than 1 million times.

In the current study, the researchers created a SERS nano-sensor by using flame spray – a well-established and cost-effective technique for depositing metallic coating – to deliver small droplets of silver nanoparticles onto a glass surface.