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Spectroscopie infrarouge déportée : mise au point d'un biocapteur pour l'imagerie métabolique et la sécurité microbiologique

Abstract : An optical chalcogenide fibre biosensor operating in the Mid-Infrared (MIR) has been developed. It enables to collect infra-Red (IR) spectra by remote spectroscopy thanks to the fibre. The principle of measurement is based on the general concept of Fibre Evanescent Wave spectroscopy. To improve the detection of such a sensor, a tapered fibre is necessary. The transportation section diameter is 450 µm, and 100 µm in the sensing zone, it is this part of the fibre which will be brought into contact with the sample to analyse. Metabolic states of a biological tissue and fluid have been characterised. Samples, mouse livers and serums, are put into contact with the fibre and MIR spectra are collected. The aim is to identify two different metabolic states (pathogenic one and normal) of a same sample. Spectral differences have been identified and assigned to metabolic alterations of glucids, lipids and/or proteins. This differences consist in an increase of the absorption bands intensity and/or shift of characteristic bands. In any case, all spectral results are in agreement with histologic staining and dosages of the sample. The second topics concerns the non-invasive and in situ monitoring of the dynamics of bacterial biofilm. The model used is an uropathogenic micro-organism, called Proteus mirabilis, which exhibits a strong swarming abilities. This bacteria has developed a complex multi-cellular behaviour correlated in space and in time, which permits itself to colonise new surfaces. The change from a vegetative to a differentiated state (pathogenic one) is accompanied by important biochemical modifications in the bacteria membrane. MIR spectra, collected during the P. mirabilis. biofilm development, allow to detect in real time a surface contamination thanks to the fibre, but also biochemical modifications of the bacteria membrane constituents. All spectra have been analysed by Principal Component Analysis (PCA) method to classify spectra by metabolic state but also to determine the spatial cartography of P. mirabilis phenotype.
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Contributor : Julie Keirsse <>
Submitted on : Friday, June 11, 2004 - 4:28:52 AM
Last modification on : Wednesday, April 7, 2021 - 3:18:04 PM
Long-term archiving on: : Wednesday, September 12, 2012 - 4:10:33 PM

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  • HAL Id : tel-00006248, version 1

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Julie Keirsse. Spectroscopie infrarouge déportée : mise au point d'un biocapteur pour l'imagerie métabolique et la sécurité microbiologique. Biochimie [q-bio.BM]. Université Rennes 1, 2003. Français. ⟨tel-00006248⟩

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