Long micro-channel electrode arrays: a novel type of regenerative peripheral nerve interface.

We have demonstrated that micro-channel electrode arrays with 100 microm x 100 microm cross-section channels support axon regeneration well, and that micro-channels of similar calibre and up to 5 mm long can support axon regeneration and vascularisation. They may be microfabricated using silicon, silicone, or polyimide and thin metal films to form 3-D bundles of long micro-channels. Arrays of "mini-nerves," i.e., miniature nerve fascicles with their own blood vessels, successfully grew through implants 0.5-5 mm long. Furthermore, guiding the regenerating nerve fibres into the small insulating channels allows for a significant increase of the extracellular (recordable) amplitude of action potentials, which promises considerable improvement for in vivo electrophysiology.