Microneedle cuff electrodes for extrafascicular peripheral nerve interfacing.

OBJECTIVE: The work presented here describes a new tool for peripheral nerve interfacing, called the microneedle cuff (μN-cuff) electrode.

APPROACH: μN arrays are designed and integrated into cuff electrodes for penetrating superficial tissues while remaining non-invasive to delicate axonal tracts.

MAIN RESULTS: In acute testing, the presence of 75 μm height μNs decreased the electrode-tissue interface impedance by 0.34 kΩ, resulting in a 0.9 mA reduction in functional stimulation thresholds and increased the signal-to-noise ratio by 9.1 dB compared to standard (needle-less) nerve cuff electrodes. Preliminary acute characterization suggests that μN-cuff electrodes provide the stability and ease of use of standard cuff electrodes while enhancing electrical interfacing characteristics.

SIGNIFICANCE: The ability to stimulate, block, and record peripheral nerve activity with greater specificity, resolution, and fidelity can enable more precise spatiotemporal control and measurement of neural circuits.