IMCN thesis defence - DELMEZ, V.

Transferring biomolecules with gas cluster ion beams by Vincent DELMEZ

Pour l’obtention du grade académique de Doctorat en sciences de l’ingénieur et technologie

Surface biofunctionalization with proteins is the key to many biomedical applications. In this work, a novel biomolecule immobilization method is proposed and developed. This solvent-free approach relies on the use of large argon gas cluster ion beams to transfer controlled amounts of protein from a solid reservoir to any chosen substrate. This method was explored with a series of peptides and proteins: angiotensin, bradykinin, neurotensin, insulin and lysozyme, which were all successfully transferred. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed the deposition pattern, allowed measuring the deposited film thickness and, combined with SDS-PAGE electrophoresis, confirmed the presence of non-fragmented protein molecules on the collectors. Lysozyme enzymatic activity could be detected on the collectors, suggesting the preservation or easy recovery in solution of the three-dimensional structure of at least a fraction of the transferred proteins. Furthermore, lowering the energy per atom in the cluster projectiles down to 1 eV allowed more than 60% of bradykinin molecules to be transferred intact. The possibility to achieve alternate multilayer buildup was demonstrated with the construction of a well-organized trilayer composed of bradykinin, neurotensin and Irganox antioxidant. These results pave the way to well-controlled protein deposition using ion beams and to the investigation of more complex multilayer architectures.

Jury members :

• Prof. Arnaud Delcorte (UCLouvain), supervisor
• Prof. Christine Dupont (UCLouvain), supervisor
• Prof. Xavier Urbain (UCLouvain), chairperson
• Prof. Sophie Demoustier (UCLouvain), secretary
• Prof. Clément Lauzin (UCLouvain)
• Prof. Laurent Houssiau (UNamur)
• Prof. David Scurr (University of Nottingham, UK)

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