Integrated on-chip microfluidic system with surface plasmon resonance biosensor for time-effective detection of legionella pneumophila in contaminated water

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Legionella are gram-negative bacteria found in natural aquatic habitats, especially in potable water, cooling tower and heat exchanger systems. These bacteria cause respiratory disease in humans when a susceptible host inhales aerosolized water or aspirates water containing the bacteria. The legionella attack the lungs and cause a life threatening pneumonia. The relevance to legionnaire's has become ever more relevant as of late, with a reported outbreak in Quebec responsible for 180 cases and 3 deaths. There are 50 bacterial strains belonging to legionella, almost half of which are documented human pathogens. Cell cultures are a common method of testing legionella in water samples. However this requires 2 days; even 2 weeks when more than one strain is present, to obtain definitive results. For species-specific detections of Legionella, oligonucleotides derived from the 16S rRNA are often used in polymerase chain reaction to obtain qualitative information. More recently, there have been extensive efforts invested in the use lab-on-a-chip devices along with the sensing technology for the detection of pathogens. Most available sensors for legionella focus on detecting one strain of the bacteria and lacks sensitivity when samples contain microroganisms that inhibit legionella growth. Herein we propose a lab-on-a chip device for the oligonucleotides derived from the 16S rRNA detection of legionella for water quality control through the integration of a digital microfluidics within label free surface plasmon resonance biosensors. Adequate signal amplification strategies and optimized surface chemistry will be implemented to achieve high sensitivity, specificity and reduced assay time. Our methodology entails several original approaches, mainly the development of a proper surface functionalization for the immobilization of DNA probe and a spectro-angular SPR biosenor working in the visible spectrum compatible with our