A regenerative microchannel neural interface for recording from and stimulating peripheral axonsin vivo

Abstract

Neural interfaces are implanted devices that couple the nervous system to electronic circuitry. They are intended for long term use to control assistive technologies such as muscle stimulators or prosthetics that compensate for loss of function due to injury. Here we present a novel design of interface for peripheral nerves. Recording from axons is complicated by the small size of extracellular potentials and the concentration of current flow at nodes of Ranvier. Confining axons to microchannels of ~100 µm diameter produces amplified potentials that are independent of node position. After implantation of microchannel arrays into rat sciatic nerve, axons regenerated through the channels forming 'mini-fascicles', each typically containing ~100 myelinated fibres and one or more blood vessels. Regenerated motor axons reconnected to distal muscles, as demonstrated by the recovery of an electromyogram and partial prevention of muscle atrophy. Efferent motor potentials and afferent signals evoked by muscle stretch or cutaneous stimulation were easily recorded from the mini-fascicles and were in the range of 35-170 µV. Individual motor units in distal musculature were activated from channels using stimulus currents in the microampere range. Microchannel interfaces are a potential solution for applications such as prosthetic limb control or enhancing recovery after nerve injury.

A Microchannel Neuroprosthesis for Bladder Control After Spinal Cord Injury in Rat

“…Microchannel implants were recorded initially by penetrating with tungsten electrodes (impedance 1 to 2 megohms at 1 kHz) (39). However, the high impedance and substantial rootlet damage sustained from penetration resulted in poor SNR ( fig.…”

Biomimetic Microelectronics for Regenerative Neuronal Cuff Implants

“…[ 18 ] The achieved device diameters of 50 µm are at least two orders of magnitude smaller compared to the stateof-the-art neuronal cuff implants. [ 23 ] We prove biocompatibility of the polymeric platform and demonstrate differentiation and guided Living species possess the ability to adapt their shape during the life cycle, e.g., through growth, replication, healing, or motion. Imitating this behavior of nature archetypes, synthetic systems attain adaptability to environmental changes (e.g., artifi cial irises [ 1 ] adjust to the light intensity) as well as possibility to interact with the environment mechanically [ 2,3 ] or chemically.…”

“…[ 18 ] At the same time, the elasticity of the polymeric layer forming the interior of the channel is about 17 MPa, which matches the elasticity of the protective tissues of the central nervous system, in line with the requirements for in vivo implants. [ 3,23 ] The total radial pressure imposed by the device upon the self-assembly process is about 600 Pa, which is well below the harm limit of 1300 Pa characteristic for nerves and axons. [ 24 ] The Swiss roll geometry with multiple windings allows the device to adjust to the dimensions of the nerves during their life circle, reducing the probability of a compression trauma.…”

Headers and Payloads Inside of Nervous System as Like as Digital Communication Protocols ?

“…The recording capabilities may be affected by biocompatibility with the patient [22], [23] y [24], traumatic nerve damage at electrode insertion [25], a bad mechanical adjustment due to the rigid electrode structure [26], tissue softness [27], non-penetration to fascicle [28], and the forces by the immobilization of the transcutaneous connection cables have been subjects treated in many publications in the last years [29], [30] y [31].…”