ED Sciences Chimiques
Electrostriction in Self-assembled Structures of Block Copolymers for Sensing and Energy Harvesting
by Agathe ZANON (Centre de Recherche Paul Pascal)
The defense will take place at 9h00 - Amphi du Centre de Recherche Paul Pascal (CRPP) 115 Avenue du Dr Albert Schweitzer, 33600 Pessac
in front of the jury composed of
- Philippe POULIN - Directeur de recherche - CRPP - Directeur de these
- Laurent RUBATAT - Maître de conférences - IPREM - Rapporteur
- Cédric SAMUEL - Professeur - IMT Nord Europe - Rapporteur
- Guillaume FLEURY - Professeur - LCPO - CoDirecteur de these
- Mickael CASTRO - Maître de conférences - IRDL - Examinateur
- Isabelle DUFOUR - Professeure - IMS Bordeaux - Examinateur
Electrostrictive polymers are attracting increasing interest due to their electromechanical coupling properties, which make them highly promising candidates for a wide range of applications operating in soft and deformable environments. These materials are particularly sought after in cutting-edge fields such as soft microrobotics, high-precision sensing, and energy harvesting. However, despite their potential, the inherently low electromechanical coupling coefficient remains a major limitation, restricting their performance in devices that require large deformations or enhanced sensitivity. Developing polymer materials that exhibit giant electrostriction therefore represents a central objective, due to the difficulty of simultaneously amplifying both the polarization and mechanical response of these systems. It is well established that the controlled incorporation of conductive inclusions within an insulating polymer matrix can induce interfacial Maxwell-Wagner-Sillars polarization, leading to a significant enhancement of electrostriction. While this strategy has enabled improvements in electromechanical coupling in numerous polymer-nanoparticle composites, it remains hindered by recurrent issues such as aggregation, local heterogeneity, and limited reproducibility. In this PhD project, we propose an innovative approach based on the self-assembly of block copolymers to design a new generation of nanostructured films with enhanced electromechanical coupling. Thanks to their sequenced architecture, block copolymers can generate well-defined periodic nanostructures, offering unprecedented control over the spatial distribution of conductive and insulating domains. In contrast to classical approaches relying on dispersed nanoparticles, this method ensures a highly ordered, aggregation-free microstructure that delivers a more homogeneous and predictable electrostrictive response, potentially amplified by collective effects at the nanoscale. This research builds on the expertise of the LCPO in the synthesis and self-assembly of sequence-controlled block copolymers, as well as on the strong competencies of the CRPP in the formulation, modeling, and advanced characterization of electrostrictive materials.
ED Sciences de la Vie et de la Santé
Novel bioprinting approaches for the creation of advanced pancreatic cancer initiation models
by Aurélien MAZET (Bioingénierie tissulaire)
The defense will take place at 13h30 - Amphithéâtre du Bâtiment Bordeaux Biologie Santé (BBS) 2 Rue Dr Hoffmann Martinot, Campus Carreire, 33000 Bordeaux
in front of the jury composed of
- Cécile HAUMAITRE - Chargée de recherche - UMR 1149 Inserm, Centre de Recherche sur l'Inflammation (CRI), Faculté de Médecine Site Bichat, Université Paris Cité - Rapporteur
- Parth CHANSORIA - Chargé de recherche - Tissue Engineering and Biofabrication Lab, ETH Zürich, CH - Rapporteur
- Sandrine DABERNAT - Professeure des universités - praticienne hospitalière - Bordeaux Institute of Oncology (BRIC), INSERM U1312, Université de Bordeaux - Examinateur
- Isabelle DUPIN - Professeure des universités - Centre de Recherche Cardio-Thoracique de Bordeaux (CRCTB), INSERM U1045, Université de Bordeaux - Examinateur
Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive malignancies, with a five-year survival rate below 15%. Its lethality stems from a clinically silent progression, late diagnosis, and highly complex biology. From the earliest stages, the pancreas undergoes profound remodeling characterized by desmoplastic reaction, activation of tumor-associated fibroblasts, progressive tissue fibrosis, and disruption of the epithelial compartment. These alterations are tightly linked to foundational genetic mutations such as KRAS within the tumor. Together, these genetic and stromal changes directly influence cellular plasticity and shape tumor trajectory even before advanced lesions appear. Although numerous PDAC models exist, none fully recapitulate the mechanical cues, stromal diversity, and tissue architecture of early disease stages. 3D bioprinting offers an innovative solution by enabling the generation of controlled 3D microenvironments that integrate stiffness, matrix composition, and cellular organization, thereby paving the way for physiopathological in vitro models dedicated to studying tumor initiation. The aim of this thesis is to develop such models and investigate how microenvironmental factors and oncogenic signals converge to influence the earliest steps of carcinogenesis. Using microvalve bioprinting, we developed strategies enabling the controlled deposition of acini isolated from either wild-type (WT) mice or KrasG12D mutant (KC) animals. Our first approach consisted in engineering four bioinks mimicking the stiffness gradients observed during the desmoplastic reaction: 90 Pa (soft tissue), 340 Pa (healthy pancreas), 950 Pa (precancerous lesions), and 2140 Pa (pancreatic fibrosis). These biocompatible bioinks enabled the establishment of a high-throughput production pipeline. Our results show that stiffness alone is sufficient to induce distinct cellular phenotypes. Specifically, KC acini cultured at 340 and 950 Pa display increased proliferation, elevated CK19 expression, and alterations in their secretome. Among these changes, we detect sustained secretion of fibroblast-activating cytokines such as Serpin E1/PAI-1. These findings highlight the importance of matrix stiffness in the emergence of tumor-promoting niches and confirm a direct mechanistic link between the matrix, genetic alterations, and modulation of the fibroblast compartment during early tumorigenesis. Given the strong basal secretion of fibroblast-activating cytokines by KC acini under physiological-like stiffness, we sought to identify potential cooperativity between oncogenic mutation and fibroblast activation. To this end, the 340-Pa model was further refined by integrating 3T3 fibroblasts with either WT or KC acini. Preliminary results show that WT models do not develop preneoplastic features, and fibroblasts do not appear to activate. In contrast, KC acini maintain their transdifferentiation phenotype. Imaging and omics analyses reveal that these changes are accompanied by a localized activation of fibroblasts at the periphery of proliferative KC acini. By combining mechanical control, automation, and compatibility with emerging spatial technologies, this work positions bioprinting as an innovative and standardized platform to investigate the initial stages of PDAC. Reproducible and high-throughput-friendly, these models offer promising opportunities for early biomarker discovery and could be extended to other cancers requiring customizable 3D systems.