Impact of the polymer design on the structure and properties of class II silicate hybrids

Many tissues have the fascinating ability to self-heal or remodel when experiencing stresses or trauma. However, above a critical defect size, our body cannot regenerate by itself leading to the formation of non-functional scar tissue. Biomaterials can be used to provide a temporary template for the damaged tissues, facilitating their full regeneration. However, the synthesis and use of such materials must adequately respond to the specific needs of the tissue targeted and therefore fulfil distinctive criteria. It is particularly true for the reconstruction of bone tissue, still lacking of an ideal synthetic biomaterials template. In this thesis, a biomimetic approach was developed to synthesise an ideal im- plant for the regeneration of hard tissues. A bottom-up strategy was used based on the sol-gel process where inorganic/organic hybrid co-networks were fabricated. To do so, bespoke polymers were synthesised containing alkoxysilane precursors which can be used to covalently bond to the growing silica network during the sol-gel process. A particular attention was brought to polymers with a high degree of cross-linking in particular homopolymers of 3-(trimethoxysilyl)propyl methacrylate and N- [3-(trimethoxysilyl)propyl] acrylamide. Models were developed and applied to experimental data to get a better insight on how these polymers affect the sol-gel process as well as the structure and properties of their resulting hybrids, as a function of the inorganic to organic ratio, molecular weight, polydispersity and synthesis methods. A good understanding of these materials is crucial to improve their properties, progressing towards an ideal implant. Hybrids were found to outperform their pure inorganic equivalent in terms of me- chanical properties, nucleation of bone like minerals, cell attachment and proliferation, presenting a huge potential for the regeneration of hard tissue.Open Acces