Une équipe de l'IRAMIS a développé des capteurs chimiques originaux pour détecter les polluants. Réalisés à base de matériaux nanoporeux, l'objectif est d'augmenter leur sensibilité et leur sélectivité, par l'incorporation de molécules avec une réactivité spécifique face au polluant cible de la sonde. Des succès notables ont été obtenus pour la mesure de la qualité de l'air (par exemple dans la détection du formaldéhyde) ou pour la métrologie des produits gazeux toxiques dans l'industrie.
One IRAMIS team has developped chemical sensors for pollutants; They are based on nanoporous materials, with the aim to increase sensitivity and selectivity with respect to various other gaseous pollutants, by incorporating probe molecules with a specific reactivity with the target pollutant. Some notable successes were obtained for the measurement of air quality (e.g. formaldehyde) or for the metrology of toxic gaseous products in industry.
The Chemical Sensors team of NIMBE/LEDNA developed innovative colorimetric sensors displaying versatile properties. The team produces transparent (allowing optical detection) matrices with tailored porosity properties(seee below) for a selective trapping of the analytes by their size. In addition, a specific intrapore pH or the hydrophobicity or hydrophilicity can be created via the introduction of functional groups in the matrices. With these two versatile features, each pore is tailored to become a nanoreactor in which a targeted chemical reaction, i.e. the reaction between a probe molecule and the analyte to be detected, can be effected. The reaction must lead to a colored product or a color change which can be easily detected.
The versatile porous materials are easily produced via the sol-gel process, a simple and soft chemistry process allowing the production of solid porous matrices, starting with metal alkoxide precursors and other reactants in solution. This nanoreactor strategy has been successfully applied for the production of the colorimetric sensors of formaldehyde and nitrogen trichloride for air quality monitoring.
A promising domain for gas sensor development is the detection of microbial contamination for food industries and health. The detection of pathogenic bacteria in clinical and food samples can often be a time-consuming and laborious process (6 to 7 days). The rapid identification of bacteria is essential for effective patient treatment in clinical settings and for determining the source of contamination in food samples. Bacteria have been shown to liberate a wide range of volatile organic compounds (VOCs), and several analytical methods focused on the detection of VOCs liberated by bacteria have been developed such as headspace solid phase microextraction (SPME) coupled with gas chromatography – mass spectrometry (GC-MS). However, clinical and food laboratories are unlikely to possess such instruments for VOC analysis; in addition, they are expensive to purchase, require both trained laboratory staff to operate and regular maintenance.
The Chemical Sensor team is developing a different strategy in this domain, and has given a proof of concept that discrimination of pathogen bacteria i.e. Escherichia Coli with simple methods is now possible.
Maj : 28/02/2016 (2593)