Design of fibers spun from carbon nanotube-sphere binary colloidal systems as substrates for cell behaviour control

The aim of this work is to design new carbon nanotube neural biomaterials shaped as fibers, where the biodegradability and biocompatibility are achieved. Capitalizing on wet spinning process, we propose a hybrid approach allowing the integration of carbon nanotubes (CNTs) in macroscopic fibers with biodegradable and biocompatible responses. This new fabrication method use the wet spinning process which eludes the CNT's covalent chemistry, thus preserving the intrinsic characteristics of nanotubes. Our concept is based on the development of a spinnable Nanotube-Sphere Binary Colloidal System (NSBCS) for a wet spinning process. It contains CNTs dispersed with sodium dodecyl sulphate (SDS) and an aqueous suspension of polylactic-co-glycolic acid (PLGA) nanoparticles combined in a variety of ratios. The efficiency of this method resides in the synergistic effect of spherical nanoparticles and rod-like particles assembled in a binary colloid system which plays a main role in the spinning process.;The method we propose promotes the spinning of CNT macroscopic fibers from a binary colloidal mixture containing CNTs combined with PLGA nanoparticles in a variety of ratios, thus resulting in fibers with various CNT content. PLGA spherical nanoparticles root the structuring of fibers, thus improving the spinnability of the mixture for the fabrication of macroscopic threads. Moreover, by spinning from a binary colloidal system, we generate new conditions for the coagulation mechanism.;By initiating the suspension of PLGA nanoparticles, we tailor the characteristics of new fibers, particularly their biodegradability and their biocompatibility. Thanks to PLGA, the fibers become partially biodegradable, which is an important achievement, considering that biodegradabilty in physiological conditions is a limitation for CNTs and PVA. The degradation process gives rise to a fibrillar structure in which CNTs form a framework-like arrangement that overwhelms the releasing effects of nanotubes, a critical point for long term biocompatibility. The permanence of nanotubes in a structured network increases the contact with cells and maintains their biofunctionality during and after the biodegradation of macroscopic fiber.;We propose a hybrid approach to produce CNT-fibers as neural biomaterial. The characteristics of these fibers, as determined through this work, demonstrate the validity of this method for the design of new fibrillar substrates for cell sustaining the growth of cells. Moreover, the presence of an aqueous coagulant medium results in the material's cleanness and allows the introduction of numerous active agents or biological molecules without their denaturation. This is an opportunity for the application of pre- or post-treatments in order to manufacture complex hybrid biomaterials containing CNTs.;The configuration of mixture dispersions at sub-microscopic and microscopic level is related to the spatial confinement created by the gaps between spherical particles. They ensure the insertion of nanotubes in the PLGA lattice and assist the formation of the fiber during the spinning process. A spatial confinement is induced through the insertion of nanotubes between the nanoparticles. It is further increased by the passage of the mixture from cylindrical syringe's needle to conical nozzle, during the injection of the mixture into the coagulation bath. At this stage of the process, the combination of the confinement effect with the shear flow action is advantageous.;The future of these fibers looks promising. They are the first fibers produced by a hybrid approach using the wet spinning process. They are in vitro biocompatible and biodegradable. (Abstract shortened by UMI.)...