Biophotonics-enabled device aims to detect Legionella bacteria in under an hour

Nov. 14, 2016

A new biophotonics-enabled device is said to spot potentially fatal Legionella bacteria 240 times quicker than current methods.

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A new biophotonics-enabled device that is said to spot potentially fatal Legionella bacteria 240 times quicker than current methods is in development, thanks to a European project dubbed Plasmonic-based autOmated lab-on-chip SEnsor for the rapid In-situ Detection of LegiONella (POSEIDON).

Legionella bacteria is responsible for Legionnaire's disease, a respiratory infection that can cause pneumonia and, in severe cases, organ failure or septic shock. With anyone being susceptible, more than 100 cases are reported each week both in America and in Europe, with a fatality rate of around 10%. Naturally occurring in freshwater lakes and rivers, the Legionella bacterium is harmless in small-enough quantities, but problems start when it multiplies in, for example, plumbing systems and air conditioning units. Here, it can be transmitted to humans when it condenses into droplets of fine mist that are inhaled and then settle in the lungs.

Legionella bacteria detection with current methods normally takes 10 days of cultivation and analysis. Recognizing this, the POSEIDON team's device aims to reduce that time to less than one hour. The device, equipped with tiny sensors, works by using surface-plasmon resonance (SPR), a method that reads information from a refracted laser beam, allowing fast, highly sensitive, inexpensive detection from a small sample without the need for labeling.

A schematic of the POSEIDON device, which uses the biophotonics technique called surface plasmon resonance, not detecting presence of Legionella bacteria.

SPR occurs when polarized beams of light hit a metal film at the interface of two media. A charge density oscillation of free electrons (or surface plasmons) at the metal film occurs, reducing the intensity of reflected light. The scale of the reduction depends on the substance on the metal at the interface. Information then gathered from the refracted can then be analyzed and a pre-programmed pathogen confirmed, resulting in an unambiguous detection of the bacteria in situ.

"Cells remain intact throughout the whole fluid transportation system in the device, and do not adhere to the fluidic piping and microfluidic channels," explains Roberto Pierobon, scientific coordinator on the POSEIDON project. "Virtually all of the bacteria cells in the sample are delivered to the sensing unit, giving extremely high sensitivity and specificity."

A schematic of the POSEIDON device, which uses the biophotonics technique called surface plasmon resonance, detecting presence of Legionella bacteria.

Hoping to have the device ready within three years, Bruno Bellò, project coordinator and CEO of Clivet, says that with future development, their device could be recalibrated to look for other pathogens.

In early 2015, the POSEIDON consortium received funding of €4,068,781 from the Photonics Public Private Partnership via the European Commission's Horizon 2020 program for a three-year research project. Coordinated in Italy, POSEIDON is comprised of a number of European partners, including Protolab, Clivet, A.R.C (Italy), Catlab (Spain), Metrohm Applikon (Netherlands), and Uppsala University (Sweden).

For more information, please visit www.poseidonproject.eu.