ED Sciences Chimiques
Multiple helices of aromatic oligoamide foldamers : design of a monomolecular triple helix and directed supramolecular self-assembly by double helix formation
by Marc-Antoine DELANNOY (Institut de Chimie & de Biologie des Membranes & des Nano-objets)
The defense will take place at 14h00 - Amphithéatre Institut Européen de Chimie et de Biologie (IECB) 2 rue Robert Escarpit, 33600 Pessac
in front of the jury composed of
- Victor MAURIZOT - Chargé de recherche - Université de Bordeaux - Directeur de these
- Sophie FAURE - Directrice de recherche - Université Clermont Auvergne - Rapporteur
- Ludovic MAILLARD - Maître de conférences - Université de Montpellier - Rapporteur
- David CANEVET - Professeur - Université Angers - Examinateur
The complex functions of proteins are intrinsically linked to their three-dimensional structures. Inspired by the folding mechanisms of these biomolecules and aiming to replicate their functions, chemists have developed unnatural oligomers that adopt architectures mimicking the secondary structures of proteins: foldamers. While their preparation and characterization are now well-established, constructing more complex architectures—combining multiple secondary elements to form tertiary and quaternary structures—remains a significant challenge, essential for the emergence of functional properties. This thesis aims to design molecular objects with complex architectures derived from aromatic amide oligomers. Following a bibliographic study presenting various synthetic molecular systems adopting multiple helical conformations, the first project discussed in this manuscript focuses on designing a molecule capable of folding into a unimolecular triple helix. In the second part, the formation of supramolecular assemblies through the self-assembly of double helices was undertaken.
ED Sciences Physiques et de l'Ingénieur
Fluid flow and interfacial deformation: nano-rheology and lift force
by Hao ZHANG (Laboratoire Ondes et Matière d'Aquitaine)
The defense will take place at 14h00 - en visioconférence
in front of the jury composed of
- Abdelhamid MAALI - Professor - Université de Bordeaux - Directeur de these
- Lionel BUREAU - Professor - Université Grenoble Alpes - Rapporteur
- Thierry ONDARÇUHU - Professor - Université Toulouse 3 - Rapporteur
- Valérie RAVAINE - Professor - Université de Bordeaux - Examinateur
- Alois WÜRGER - Professor - Université de Bordeaux - Examinateur
- Emilie VERNEUIL - Chargée de recherche - CNRS ESPCI paris - Examinateur
This thesis investigates the interplay between fluid flow and interfacial deformation using Atomic Force Microscopy (AFM). First, AFM was employed to explore the resonant thermal capillary fluctuations (RTCF) of bubble and drop surfaces, enabling the measurement of surface elasticity and bulk viscosity in surfactant-laden air/water interfaces and polymer solutions. These measurements extended the frequency range for rheological investigations, effectively overcoming the limitations of classical rheometers. Next, we introduced a non-contact method to assess the mechanical properties of living cells based on the elastohydrodynamic (EHD) interaction between the thermal vibrations of the AFM cantilever and the cell deformations. This method enabled the precise determination of the elastic modulus of a living cell for different frequencies. Finally, we conducted the first direct and quantitative measurement of the lift force acting on a sphere moving along a liquid-liquid interface. This force, arising from the coupling between viscous flow and capillary deformation of the interface, was measured as a function of the distance between the sphere and the interface using an atomic force microscope (AFM). We investigated various liquid interfaces, working frequencies, sliding velocities, and two different sphere radii. The findings provide valuable insights into interfacial phenomena and enhance the understanding of interactions between fluid flow and soft interfaces.