A small sensor for detecting pesticides on fruit has been developed by researchers. A paper in the journal Advanced Science describes a technique that uses flame-sprayed silver particles to amplify the signal of chemicals. The researchers hope they can help uncover food pesticides before they are eaten.
According to reports, up to half of all fruits sold in the EU have pesticides in them. Current techniques for detecting pesticides on single products before they are consumed are limited by high cost and cumbersome manufacturing of its sensors. We were able to overcome this by developing inexpensive and reproducible nano-sensors that could be used to monitor fruit pesticides.
SERS is a 1970s discovery that can increase the diagnostic signals of biomolecules on metal surfaces by more than one million times. The technology has been used in a number of research fields. High production costs and limited reproducibility have made food safety diagnostics difficult to apply.
The technology is called flame spray.
The researchers used flame spray to deliver small droplets of silver to a glass surface.
According to the study's first author, the flame spray can be used to quickly produce uniform SERS films across large areas.
The researchers adjusted the distance between the silver particles to make them more sensitive. They applied a thin layer of dye on top of the sensors to see if they could detect substances. The shelf life potential and feasibility for large-scale production of the sensors is underscored by the fact that their performance remained intact after 2.5 months of testing.
Pesticides were detected on apples.
The researchers tested the sensor's practical application by detecting low concentrations of parathion-ethyl, which is banned or restricted in most countries. An apple had a small amount of parathion-ethyl put on it. The cotton sample was immersed in a solution to destroy the pesticides. The solution was put on the sensor to confirm the presence of pesticides.
Haipeng Li says that their sensors can detect pesticide on apples in a few minutes. We offer a proof of concept practical application for food safety testing.
The researchers want to see if thenano-sensors can be applied to other areas, such as discovering markers for specific diseases at the point of care.
More information: SERS Hotspot Engineering by Aerosol Self-Assembly of Plasmonic Ag Nanoaggregates with Tunable Interparticle Distance, Advanced Science (2022). DOI: 10.1002/advs.202201133 Journal information: Advanced Science
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