Light sensor to spot Legionella in minutes

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The European group POSEIDON, (or ‘Plasmonic-based automated lab-on-chip sensor for the rapid in-situ detection of Legionella’) has developed a biophotonic light sensor capable of detecting Legionella bacteria in under one hour – a process that normally takes 10 days of cultivation and analysis.

Legionella bacteria can be found in bodies of water, including air conditioning units, plumbing systems, Jacuzzis, fountains or public water supplies.

Scientific coordinator, Roberto Pierobon, explained: “POSEIDON is a first for detecting Legionella with light and provides an inexpensive, user friendly early warning system on an air-conditioning unit.”

Equipped with sensors, the scanner works by using the photonics technique of Surface Plasmon Resonance (SPR), a procedure that reads information from a refracted laser beam without the need for ‘labelling’, the process of binding to a protein.

SPR occurs when polarised beams of light hit a metal film, resulting in a charge density oscillation of free electrons which reduces the intensity of reflected light. The scale of the reduction depends on the substance on the metal at the interface. Information gathered from the refracted beam can then be analysed, and a pre-programmed pathogen confirmed.

“With future developments, the device could be recalibrated to look for other pathogens, which would provide safety options for the environmental, medical or food industries,” added Bruno Bellò, project coordinator.