La défense publique de la thèse de Monsieur Xavier Carette aura lieu le 15 décembre 2020 à 15h15 par vidéo-conférence, via ce lien

Promoteur de thèse: Monsieur Jean-Marie Raquez et Madame Rosica MINCHEVA (co-promoteur)

Résumé

This aim of the thesis is dedicated to the elaboration of new materials for bone tissue engineering based on polylactic(acid) matrix and hydroxyapatite filler particles. The stabilization of the interface between this hydrophobic matrix and these hydrophilic fillers is the first goal of this work. Three different ways were investigated from the non-covalent stabilization by the use of PEG-b-PLA surfactant to covalent modification by grafting polymerization of lactide and plasma polymerization of acetylene. We succeeded in all cases to stabilize the interface inducing a good dispersion of the filler leading to an increase of mechanical properties and especially for the plasma-polymerized functionalized particles. As we succeeded to modulate the bulk properties of these composites, the second objective of my thesis was to improve the cell recognition site and other biological properties such as the antimicrobial activity by surface-modifying the matrix PLA through chitosan grafting. Chitosan has thereby shown its efficiency as a surface-modifier for bone reconstruction therapy. However, the modification of the polysaccharide is often required for its effective immobilization onto, e.g., a PLA surface. We decided to develop a new process that has the potential to be industrialized, and which is able to functionalize 3D materials, i.e., atmospheric plasma modification of PLA followed by a dip-coating process. Through this simple method, a stable coating of chitosan was obtained. The characterization of the coating reveals a non-covalent immobilization of this layer, which conserve the antimicrobial properties of chitosan. In conclusion, we produced different new materials for bone tissue engineering made of PLA and hydroxyapatite that could be combined with the new coating process resulting in a full device that is of high interest for clinical use.