Fabrication, caractérisation et application de surfaces organiques fonctionnalisées pour le génie tissulaire

The interactions between a biomaterial and a biological environment are largely influenced by surface chemistry, which can be controlled in order to enhance cell adhesion. This can be applied to the design of vascular grafts, the internal walls of which need to be fully covered by an endothelial cell layer in order to prevent harmful outcomes such as thrombosis. Various processes were considered in this project, in order to identify which coatings and chemical groups are the most advantageous for enhanced endothelial cell adhesion and -growth. Nitrogen-rich surfaces were obtained on polyethylene terephthtalate (PET) films by plasma treatment (NH3 plasma modification, PETf), plasma polymerization (L-PPE:N), chemical vapor deposition (Parylene diX AM) or liquid-chemical covalent grafting of a polymer (PAAm); plasma polymerization was also used to create oxygen-rich films (L-PPE:O), as well as hybrid coatings containing both oxygen and nitrogen-based groups (L-PPE:O,N), on PET films. These surfaces were compared to commercial culture plates such as oxygen-rich Tissue Culture Polystyrene (TCP, ―Falcon™‖) and hybrid Primaria™, both developed and marketed by Corning Inc. and known for their ability to promote cell adhesion. The chemistry of all these surfaces was analyzed by X-ray photoelectron spectroscopy (XPS), and endothelial (HUVEC) cells were used to assess their ability to enhance cell adhesion. Primary amine groups (-NH2), well known to enhance cell adhesion, were quantified on the nitrogen-rich surfaces by chemical derivatization, while the colorimetric method based on Orange II dye was used for comparison. In addition, the deposition rate and the solubility of newly developed hybrid L-PPE:O,N coatings were evaluated. All of the surfaces investigated were found to be highly functionalized; the XPS analyses of PETf, TCP and Primaria™ at grazing angles showed this functionalization to reside only very near the surface (a few nm deep). Excellent cell proliferation was observed on nitrogen-rich L-PPE:N, PETf and PAAm, as well as on oxygen-rich L-PPE:O, with an efficacy comparable to TCP. These results prove that the efficacy of moieties created on these surfaces, especially of carboxylic and primary amine groups, seemed to play a key role in cell adhesion. Furthermore, the cellular behavior was found to be very similar on these diverse surfaces, despite their different chemical compositions. This suggests that a concentration threshold of ―active‖ moieties was reached for both oxygen- and nitrogen-containing surfaces, with a similar efficacy to foster cell adhesion, above which threshold their quantities no longer appear to influence cell