Biomimetic Approaches to Peripheral Neuroprosthetic Interfaces

This chapter reviews the principles that have guided materials selection, fabrication and surgical techniques for neuroprosthetic interfaces. As the field has developed, it has moved away from high modulus materials toward softer materials. Initially epoxy was the material of choice for interface research, but as microfabrication techniques developed for the transistor industry the field moved to silicon. Since that time researchers have experimented with polyimide and are now exploring the use of materials that match the modulus of the peripheral nervous system. Novel fabrication and coating techniques have enabled the field to move toward more biologically friendly soft materials which have the potential to minimize degradation of the electrode/nerve interface. More attention is also now focused upon biological response to materials and the potentially deleterious effects of immune reactions and fibrosis upon signal acquisition. Interfaces of the future will likely need to match not only mechanical properties such as modulus of elasticity but also molecular biocompatibility. Newer microsurgical techniques may need to be developed to attach implants to ends of severed nerves and direct regeneration into the interfaces. The introduction of the softer materials has enabled suturing directly to the implant when combined with microsurgical techniques.