• biocompatibility
• intraneural electrode
• materials
• Q-PINE

Vagus nerve dysfunctions are associated with pathologies related to many organs, like heart failure (HF), obesity, and mood disorders. A possible treatment is proposed by bioelectronic medicine. This research field focuses on the electrical stimulation of the nerves, trying to restore their physiological functions. The devices used are called neural interfaces. For the vagus nerve, this therapy is called vagus nerve stimulation (VNS). Current technologies for VNS involve extraneural approaches, which are devices that enwrap the nerve inducing electrical pulses from the outside. However, those have many problems related to adverse effects, due to their low selectivity. Intraneural approaches have been proposed to overcome those limitations. The focus of this work is the increasing of the long-term biocompatibility of the Q-PINE, an intraneural electrode used for the vagus nerve, to be used in chronic implants. The components of the Q-PINE have been analysed, together with the materials used, and a new design has been realised. Then, a material study was performed to identify suitable biomaterials for long-term applications in neuroprostheses. These material are liquid crystal polymers (LCP), polyimide (PI) and polyetheretherketone (PEEK). Among these, PEEK was selected for the new version of the Q-PINE. Moreover, also the glues holding together different components of the Q-PINE have been substituted with UV biocompatible glues certified by ISO standards. Mechanical tests were performed to evaluate the forces involved in the implantation procedure. The results suggest that PEEK is a feasible choice since it does not alter the implantation mechanics and increases the possibility of the Q-PINE to be used in long-term applications.