EU collaboration claims new photonic technique will slash detection time by not requiring combination with protein
The European collaborative Poseidon project says it has developed a scanner that can detect Legionella bacteria in under one hour, rather than the 10 days of cultivation and analysis normally required.
The scanner, equipped with tiney sensors, uses the technique of Surface Plasmon Resonance (SPR), a procedure that reads information from a refracted laser beam. According to Poseidon, this allows fast, highly sensitive, inexpensive detection from a small sample without the need for ‘labelling’, the process of binding to a protein in order to be detected.
Scientific coordinator, Roberto Pierobon said: “Poseidon is a first for detecting Legionella with light and provides an inexpensive, user-friendly, state of the art early warning system on an air-conditioning unit. We aim to reduce the time involved in a diagnosis from 10 days to less than 1 hour. In order to prevent outbreaks at critical times of the year, we should be talking about a matter of minutes, rather than days.”
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 can then be analysed, and a pre-programmed pathogen confirmed, resulting in ‘an unambiguous detection’ of the bacteria in situ, the group says
Mr Pierobon added: “Detection and investigation of viruses and bacteria is a rapidly growing field in SPR bio sensing, but the detection has only been achieved in laboratory settings. With our unique SPR sensing architecture, Poseidon provides reliable measurement readouts of legionella bacterial cells that are driven and entrapped on a custom sensing surface, specifically designed with opportune positive and negative controls.”
“Cells remain intact throughout the whole fluid transportation system in the device, and do not adhere to the piping and microfluidic channels. Virtually all of the bacteria cells in the sample are delivered to the sensing unit, giving extremely high sensitivity and specificity.”
Approximately 5,000 Legionella cases are reported annually in the United States every year, while 2013 saw 5,851 cases reported by 28 EU Member States and Norway, according to the European Centre for Disease Prevention & Control (ECDC).
Bruno Bellò, project coordinator and CEO of Clivet, one of the Poseidon partners, is excited about the implications for the future which could see detectors commercially available within three years. He said: “The exciting feature of this device is that with future development, it could be recalibrated to look for other pathogens, which would provide incredible safety options for the environmental, medical or food industries.”
Italy-based Poseidon comprise a number of European partners, including Protolab, Clivet and ARC (Italy), Catlab (Spain), Metrohm Applikon (Netherlands), and Uppsala University (Sweden).
Poseidon stands for ‘Plasmonic-based automated lab-on-chip sensor for the rapid in-situ detection of Legionella’.