[|Vendredi 13 Mai 2011 à 10h00|]
[|Salle IAM UFR Sciences|]
[|Pour obtenir le grade de Docteur de l’université du Maine
Spécialité : Chimie et physico-chimie des polymères|]
[|Thèse préparée au laboratoire de Polymères, colloïdes et Interfaces UMR 6120 CNRS
Centre de Transfert de Technologies du Mans (CTTM), France
Jožef Stefan International Postgraduate School (IJS), Ljubljana, Slovenia|]
[|« Development of new anti-bioadhesive surfaces for specific neurodegenerative agents »|]
Devant le jury composé de :
|K. ANSELME||Docteur||IS2M, Mulhouse||Rapporteur|
|U. CVELBAR||Maître de conférence H.D.R.||IJS, Ljubljana||Rapporteur|
|R. BRIANDET||Docteur||INRA, Paris||Examinateur|
|B. EL MOUALIJ||Docteur||ULG, Liège||Examinateur|
|G. LEGEAY||Docteur||CTTM, Le Mans||Examinateur|
|D. DEBARNOT||Docteur||PCI, Le Mans||Examinateur|
|M. MOZETIC||Professeur||IJS, Ljubljana||Directeur|
|F. PONCIN- EPAILLARD||Directrice de recherche||PCI, Le Mans||Directeur|
The research work presented in this thesis considers the development of new biocompatible surfaces that are able to control the adhesion of pathogenic agents responsible for the development of neurodegenerative diseases such as Creutzfeldt–Jakob, Alzheimer, Parkinson and Lewis body disease. Our approach was focused on problems before the detection step, particularly on the improvement of Eppendorf tubes that are used for the storage of body fluids like cerebrospinal fluid and blood. These tubes made of polypropylene induce the depletion of genetic material, in some cases even over 70%, resulting in a low concentration of pathogenic agents for the further immunoenzymatic detection.
With the purpose to reduce the adhesion of neurodegenerative proteins on the surface of supports, two courses of treatments were anticipated. The first one consists of surface modification by highly reactive fluorine plasma treatment and the second one incorporates development of new hydrophilic surfaces by coupling two techniques, plasma activation and subsequent grafting of polymer materials. With the latter approach, an original way of surface modification has been attained by using complex solutions of polymers and surfactants that permits controlled configuration of nanostructured surfaces. All steps of surface modifications were well characterized by different physicochemical methods. The surface hydrophilic/hydrophobic character was determined by measurements of polar and apolar surface energy, surface charge by magnitude of zeta potential, surface chemistry was evaluated by x-ray photoelectron spectroscopy (XPS), while the surface roughness and topography were monitored by atomic force microscopy (AFM). The interactions between functional groups of treated supports and antigen proteins were interpreted referring to different models of adhesion established for a range of pH values close to the classical biological protocols.
Finally, in order to validate that the new surfaces are able to prevent or decrease the adhesion of neurodegenerative agents on the surfaces of Eppendorf tubes, the immunoenzymatic analyses were carried out in hospital centres of partners that were participating to the project STREP NEUROSREEN n° LSHB-CT-2006-03 7719 (Centre de Recherche sur les Protéines Prion ; Liege (ULG), Hospices Civils de Lyon (CHUL) and Lancaster University (L-UNI)). These analyses showed that the treatments led to a decrease of antigen adsorption up to 100%, enabling (allowing) better detection of pathogenic agents.