A sieve electrode as a potential autonomic neural interface for bionic medicine.

We examined the applicability of a sieve electrode to the autonomic nervous system as a potential neural interface for bionic medicine. We developed, using a Si-semiconductor process, a sieve electrode having a square diaphragm (1 mm in one side, 12 microm in thickness) with 30-81 penetrating square holes (50-100 microm in one side). In the first protocol, we implanted the sieve electrode to the vagal nerve in rats. One hundred and twenty days after the implantation, cuff electrodes were attached to the vagal nerve proximal and distal to the sieve electrode under halothane anesthesia. The evoked action potential was recorded from the sieve electrode by nerve stimulation via the cuff electrodes. The evoked action potential was also recorded from the cuff electrodes by nerve stimulation via the sieve electrode. In the second protocol, we implanted the sieve electrode to the renal sympathetic nerve in rabbits. Forty days after the implantation, the spontaneous action potential or sympathetic nerve activity was recorded under pentobarbital anesthesia. In conclusion, we were able to record the evoked and spontaneous action potentials using the sieve electrode. The sieve electrode will provide a useful neural interface for recording and stimulating the autonomic nervous system.