Regenerative Sieve Electrodes Induce Sensory Percepts via Electrical Stimulation of Peripheral Nerve Fibers
Matthew R MacEwan, PhD1; Juan Pardo, BS2; Nikhil Chandra, BS2; Daniel W. Moran, Ph.D.3; Wilson Z. Ray, MD4; (1)Washington University School of Medicine, Saint Louis, MO, (2)Washington University in St. Louis, Saint Louis, MO, (3)Washington University in St. Louis, St. Loius, MO, (4)Department of Neurological Surgery, Washington University School of Medicine, St. Louis, MO
Introduction:Regenerative sieve electrodes represent a novel means of facilitating chronic high-specificity nerve stimulation needed to restore sensorimotor function following neurological injury. Yet, regenerative sieve electrodes have yet to be proven as a stable interface to sensory nerve fibers capable of inducing actionable sensory percepts. The present study aimed to examine the ability of chronically implanted regenerative sieve electrodes to functionally interface sensory axons in mammalian mixed nerve and exogenously induce cortical signatures of peripheral sensation.
Materials & Methods: Custom-designed sieve electrodes were fabricated out of polyimide and gold using sacrificial photolithography. Regenerative sieve electrodes were then microsurgically implanted in the sciatic nerve of male Lewis rats for 1, 2, and 3 months. Nerve interfacing was assessed in situ by selectively stimulating regenerated nerve tissue via implanted sieve electrodes while simultaneously mapping activation in sensory cortex (S1) utilizing penetrating silicon microelectrodes.
Results: Micro-surgical implantation of sieve electrodes in the sciatic nerve of healthy male rats for 1, 2, and 3 months demonstrated robust axonal regeneration through implanted devices. Sensory mapping demonstrated progressive restoration of sensory on the plantar surface of the paw over 1-3 months. Chronically implanted sieve electrodes demonstrated successful and independent recruitment of sensory nerve fibers and induction of neural activity in somatosensory cortex (S1). Mapping of the sensory cortex (S1) utilizing silicon microelectrode arrays further elucidate the selective nature of sensory fiber activation.
Conclusions: The present study confirms the ability of sieve electrodes to facilitate selective, stable activation of sensory nerve fibers. These findings suggest that regenerative sieve electrodes may be able to provide a stable interface ideal for translational use in advanced neuroprosthetic systems.
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