The new biophotonic light sensor can detect Legionella bacteria in less than an hour. Image courtesy of Sebastian Kaulitzki/Shutterstock.com.
The new biophotonic light sensor can detect Legionella bacteria in less than an hour. Image courtesy of Sebastian Kaulitzki/Shutterstock.com.

A European group, POSEIDON, has developed a sensor which can spot the Legionella bacteria in minutes, 240 times faster than current methods.

POSEIDON stands for ‘Plasmonic-based automated lab-on-chip sensor for the rapid in-situ detection of Legionella’ and the new biophotonic light sensor can detect the Legionella bacteria in less than an hour, a process which normally take 10 days of cultivation and analysis.

Coordinated in Italy, Poseidon is comprised of several European partners, including those in Italy, Spain, the Netherlands and Sweden. It recently received funding of more than €4 million from the Photonics Public Private Partnership (PPP), via the European Commission’s H2020 programme for a three-year research project.

Equipped with tiny sensors, the device works by using the photonics technique of Surface Plasmon Resonance (SPR), a procedure that reads information from a refracted laser beam, allowing fast, highly sensitive, inexpensive detection from a small sample without the need for ‘labelling’, the process of binding to a protein so that it can be detected.

SPR occurs when polarised 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 gathered from the refracted can then be analysed, and a pre-programmed pathogen confirmed, resulting in an unambiguous detection of the bacteria in situ.

Detection and investigation of viruses, bacteria and eukaryotic cells is a rapidly growing field in SPR bio sensing, but the detection has only previously been achieved in laboratory settings.

Legionnaire’s Disease is a respiratory infection that can cause pneumonia, and in severe cases organ failure or septic shock.  Naturally occurring in freshwater lakes and rivers, the Legionella bacterium is harmless in small quantities, but problems start when it multiplies in plumbing systems, air conditioning units, or in a public water supply. Here it can be transmitted to humans when it condenses into droplets of fine mist which are inhaled and then settle in the lungs.

Legionella bacteria survive and flourish at temperatures between 25º to 45º C, and are normally killed off by heating water units above 70º C. However new bacteria can form quickly, and sometimes not all of the pathogens are removed. The Poseidon project aims to remove the uncertainty involved.