A biohybrid microprobe for implanting into the peripheral nervous system

Peripheral nerves have been previously interfaced with multi-electrode structures including sieve-shaped designs for regeneration of peripheral nerve axons through the sieve and cuff-shaped microelectrodes for interfacing intact peripheral nerve bundles. Both approaches assume intact motor neurons and neuromuscular junctions for excitation of skeletal muscle. An innovative biohybrid microdevice has been developed for housing gene manipulated nerve cell complexes on the microprobe. The microprobe is designed for implantation and for subsequent out-sprouting of probe based neural cells, generating a biological junction with the targeted skeletal muscle. Polymer micromachining technology has been applied to microfabricate 3-D flexible polymer structures with embedded microelectrodes. Adherence and growth of gene manipulated OLN-93 nerve cells on the probes have been investigated. Microprobes without cells have been implanted into the proximal stump of the sciatic nerve in the rat. Results demonstrate that the new design of 3-D biohybrid microprobes is well suited for implantation into the peripheral nervous system. OLN-93 nerve cells could adhere and grow on the microprobes under in-vitro conditions. The microprobes remained biostable and fixed at the original sites of the sciatic nerve 11 month after implantation.