Facts: The new method
The researchers manufactured nanosensors with flame technology. It is a well-established and cost-effective method for producing coatings on metal surfaces and therefore enables large-scale production.
The sensor consists of micrometer-thin layers of silver nanoparticles on a glass surface. Toxic tracers were applied to the sensor and the signal was measured with a spectrometer. The sensors continued to function during repeated testing after more than two months, which according to the researchers shows the sensors’ durability and suitability for mass production.
The research has been funded with support from the European Research Council, Karolinska Institutet, the Foundation for Strategic Research and the Swedish Research Council.
Source: Karolinska Institutet
“Reports show that more than half of all fruit sold in the EU contains traces of pesticides that in higher doses have been linked to human health problems,” said Georgios Sotiriou, a researcher at Karolinska Institutet, in a press release.
It is possible to test individual fruits for pesticides, but in the past it has been difficult. The basic technology, surface-reinforced frame propagation, was developed in the 1970s and is used in several research fields. But in food safety, use has been limited because it has been too expensive and required specially trained personnel, says Haipeng Li, one of the researchers behind the study.
– We have developed a nanosensor that is much cheaper than previous methods. The entire equipment can fit in a backpack.
In the study, the researchers created sensors that can detect an insecticidal poison that is banned in many countries. They then applied a small amount of the poison to an apple, collected it with a cotton swab, mixed it with a solution in a tube and dropped it on the sensor which confirmed its presence.
– It is not a huge discovery in itself but it is an important step, says Haipeng Li.
In the future, Haipeng Li hopes that the sensors can detect mixtures of pesticides. Just mixed pesticides can be extra dangerous and are difficult to detect with existing methods. If the research is successful, he envisions that larger grocery stores can buy their own sensor.
The researchers will also investigate whether the method can be used to detect diseases in care environments with limited resources.