Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - POSEIDON (Plasmonic-based autOmated lab-on-chip SEnsor for the rapid In-situ Detection of LegiONella)

Teaser

Legionnaires’ disease is a serious form of pneumonia caused by bacterium Legionella Pneumophila, with a case-fatality ratio on the order of 10-15%. L. Pneumophila proliferates in aquatic habitats, especially in potable water, air conditioning, hot and cold water systems...

Summary

Legionnaires’ disease is a serious form of pneumonia caused by bacterium Legionella Pneumophila, with a case-fatality ratio on the order of 10-15%. L. Pneumophila proliferates in aquatic habitats, especially in potable water, air conditioning, hot and cold water systems, cooling towers, evaporative condensers, spa/natural pools. Actually, its detection and monitoring rely on time-consuming protocols (in the order of several days) based on in vitro selective bacteria culture methods, performed by highly specialised personnel in dedicated laboratories. Poseidon project targets to change the approach to bacteriological environmental monitoring and to the management of the risks related to Legionella infections by developing a fully automatic and reliable system. This detection platform is designed to collect and sequentially concentrate water and air samples, which then are injected into a microfluidic system, and delivered to the SPR sensor for analysis.

Work performed

At the mid-term of the Poseidon project, each of the subsystems composing the detection platform has been properly implemented and continuous improvement work is ongoing as planned.

Three different architectures of sampling and conditioning unit have been studied and a unique architecture for the possible integration of both devices for air and water sampling has been adopted. First demonstrators have been fabricated, tested and are actually under evaluation in classified laboratories for the validation of their performances following gold standard method ISO 11731.
Concerning the microfluidic platform, different modes of hydrodynamic fractionation were initially evaluated, but the demanding requirements led to change the approach and to develop a microfluidic evaporator that seemed robust and efficient enough to concentrate the sample. A prototype of such a system has been designed and fabricated and first trials exhibited promising results. After an extensive and deep experimental campaign, the concentrators based on teflon membrane did not fulfil the Poseidon demands, and this technology could not be pushed to the extent of not having losses, despite all effort to improve it. New approaches were deeply studied and several designs were tested. Last concentrator devices based on a totally original idea have been realized and are exhibiting performances in line with project demands. Possible ways to transfer the final concentrated volume to the SPR sensor are under evaluation.
The complete microfluidic chip with chamber and inlet/outlet channels has been fabricated and different master crafting approaches have been tested. In order to avoid air bubbles, which are a major issue in microfluidics, a novel degassing system has been designed, integrated in the fluidic design and evaluated.
A sticky sealing interface for the channel structure has been investigated for different application methods, layer thicknesses, curing times and temperatures: the approach has provided promising results, e.g. allowing the system to withstand sufficient pressure to flood the channels and perform dynamic addressing of fluids. Hydrodynamic addressing by tuning the pressures of the sources was selected as the strategy for fluidic control and has been confirmed in devices which were completely sealed.
Regarding the SPR detection system, FEM simulations on different architectures for digital and sinusoidal gratings have been carried out, in order to optimize signal and sensitivity. Fabrication of sensing components has been achieved on both LIL (Laser Interference Lithography) and EBL (Electron Beam Lithography) technologies and different sensing configurations have been investigated. Optimization work will continue to the second year of project. Moreover, the design of customized mechanical parts of DVD technology process were evaluated to realize custom gratings and the protocol for gratings manufacturing through DVD industrial process has been defined, as well as the modalities to create specific substrate through LIL: therefore, DVD-based gratings have been studied, fabricated and tested.
Strategy for functionalization of grating surface has been defined and tested as well as the anti-legionella antibodies have been selected and the performances verified on two ATCC strains (L. pneumophila and L. dumoffi) using a fluorescent analysis on whole cells. The functionalization procedure has been validated in terms of dressing and functional groups exposed, of antibody binding and of antifouling activity of the dressing over gold surfaces. The performances of different spacers have been evaluated as well. The deposition protocol and the target-antibody reaction have been assessed, optimized and finally translated for the creation of the capture layer on gold surfaces.
The detection system has been designed and the demonstrator has been implemented to allow both reflectance and transmittance analysis and polarization angle modulation analysis. On the

Final results

The Poseidon project will impact on sustaining Europe\'s industrial competitiveness and securing industrial technology leadership by introducing new solutions in the environmental monitoring and bacteriological risk management, and on tackling relevant health and safety societal challenges.
The coordinator is a leading European company that designs, produces and distributes systems for air conditioning, heating, fresh air and purification with a wide range of solutions for residential, commercial and industrial applications. This strong industrial commitment pushes to maximise exploitation of project successes and to solidly impact on many levels of scientific, technological and societal areas with a planned and capillary employment of the fully automated developed system. The possibility to obtain results in few hours, compared with several days required for conventional microbiological in vitro tests, will enable new approach to bacteriological environmental monitoring. This may have breakthrough impacts in the economic exploitation of new-generation devices with improved safety characteristics in many areas, such as the possibility of prompt sterilization response when alert levels of L. pneumophila are detected. At the same time the Poseidon project will strengthen the competitiveness and growth of participating companies by developing innovations meeting the needs of European and global markets, and by bringing such innovations closer to these markets. Remote monitoring is another prospect that would determine further improvements and commercialization opportunities, including smart grids in residential buildings and large infrastructures. This “new device concept” could potentially first integrate and then replace the current best practice and standard methodology protocol (culture test) through which L. pneumophila is identified and quantified. From a scientific viewpoint, the azimuthally-rotated plasmon sensing concept is an innovative approach towards more compact, faster and cheaper sensing devices based on grating-coupled polarization-modulation SPR, which could be applicable also in other scientific fields. Design, production and integration of a microfluidic device allowing transport of whole bacteria cells and the bacteria-antibody interaction on a bio-functionalized surface is transversal to different lab-on-chip applications.
Moreover, the project will enhance innovation capacity and integration of new knowledge in fields of plasmonic sensing, microfluidics and surface functionalization. The core photonics idea has good potential for the proposed application and could be an excellent example of nanotechnology fabrication having a route to low cost manufacture by using existing DVD manufacturing methods. In fact, the fabrication of plasmonic gratings through fast and cheap nanoimprinting techniques on widely available supports (such as DVDs and CDs) makes the whole process cheaper, increasing the potential market penetration of the new devices. Because the need of a microbiological facility is eliminated, the costs are further reduced.
Regarding societal impact and security, the availability of fast and reliable detection of L. pneumophila is expected to decrease the number of outbreaks, resulting in improved health conditions especially among persons that are more exposed to infections, e.g. immunocompromised and elderly patients. Reduction of the sanitary costs for the management of legionella-induced infections are also expected due to the possibility to increase frequency of monitoring and subsequent promptness of the decontamination procedures, resulting in a final overall decrease in the number of the infection episodes. Furthermore, the features of the proposed device include reduction of risk associated with possible contamination for the operator, as the test procedure should require little, if any, intervention by the operator and it is completely safe for the people working in the monitoring area a

Website & more info

More info: http://www.poseidonproject.eu.