The work carried out has provided fundamental advances to accomplish the objectives of the project. From a technical point of view, the project was founded on developing microfibres (MFs) with improved mechanical and electrical properties (WP-1), and electrical interconnection (WP-2). Because mechanical mismatching between the interconnected MFs and the neural tissue, or breaking of the MFs, may lead to complete failure of the proposed therapeutic approach, WP-3 dealt with the mechanical features of the MFs and the MF/tissue interplay. Biomolecules at the MF surface strongly influence cell responses to the MFs. Therefore, WP-4 developed affibodies for MF functionalisation. The added effort of WPs 1, 2, 3, and 4 generated a MF-based electroconductive scaffold suitable for implantation and electrostimulation of the spinal cord. Cellular responses to the isolated components and the connected system were investigated in transgenic mice in WP-5 and 6; whereas the sensory and motor effects of the active bio-electrical system were assessed in rats and pigs in WP-7.
The work plan and the objectives of the project were extremely challenging and multiple technical difficulties arose. The novel and risky approach followed in Neurofibres faced challenging problems associated to the implant of electrodes in regions of open central nervous system trauma. Nevertheless, the consortium was able to navigate those difficulties and developed the basic tools needed and the experiments proposed. Graphene-coated carbon MFs, affibodies, interconnected carbon MF assemblies, and epidural electrodes were produced and were comprehensively tested in rodent and/or porcine models of SCI. Finally, we have demonstrated that the original goal of the project is feasible.The data obtained so far provide further support to the use of electroconducting microfibres for the treatment of spinal cord injury. However, we have not yet achieved functional recovery in porcine SCI. Additional strategies, including the combination of the electroactive implant with other therapeutic strategies are under exploration to guarantee that the new technologies find the pathway towards clinical application.
