Mémoire, partim B: Development of techniques for scaffolding amorphous polyphosphoesters in nanofiber fabric

Abstract

In the context of numerous biomedical applications such as drug delivery and tissue engineering, it is necessary to use polymers that meet certain requirements such as biocompatibility with the human body and biodegradability. This means that the polymer used must not be recognized as a foreign body by the human body and must not pose potential toxicity. Additionally, in the context of tissue engineering, the polymer material used must be able to adhere and meet the requirements of its application, thus requiring adequate structure and mechanical properties. In this thesis, polyphosphoesters, a class of polymer that perfectly meets the properties of biocompatibility and biodegradability, are studied. Polyphosphoesters indeed have a structure similar to DNA strands, making them biocompatible, and ester bonds are easily hydrolyzable, making them easily degradable. However, in the context of tissue engineering, it is still necessary to be able to implement PPEs. The objective of this thesis is therefore to create a nanofiber mat of PPEs. The nanofiber structure increases adhesion and the contact surface with biological tissue. To create this structure, it is necessary to use polymer processing techniques such as electrospinning, which is the technique used in this thesis to create nanofiber structures. Two experimental studies are undertaken to achieve this objective. The first research aims to create a polymer filament using electrospinning. To do this, it is essential to control the viscosity of the polymer solutions. Viscosity directly influences the formation of nanofibers and the quality of the final tissue. Thus, experiments are conducted to adjust the viscosity of the polymer solutions by varying parameters such as the nature of polymers and molar mass. The second research focuses on attaching the nanofiber tissue to the collector. This step is important to ensure the strength and structure of the final tissue. For this, The technique studied is polymer photo-crosslinking. It is therefore necessary, first, to ensure that the photo-crosslinking reaction occurs, and secondly, to improve the fixing speed so that the polymer is fixed directly after deposition on the collector, thus creating a nanofiber structure. By combining these two experimental studies, the thesis aims to optimize the electrospinning process and for the manufacture of tissue from polyphosphoesters with a fibrous structure. The results of these experiments will provide valuable information for the design and production of advanced biomedical materials, with potential applications in the field of regenerative medicine, implants, and medical devices.