Date of Award

6-2026

Degree Name

MS in Biomedical Engineering

Department/Program

Biomedical Engineering

College

College of Engineering

Advisor

Robert Szalvik

Advisor Department

Biomedical Engineering

Advisor College

College of Engineering

Abstract

Peripheral nerve stimulation is clinically used to manage pain, rehabilitate motor function, and promote nerve regeneration. The sciatic nerve is often studied for stimulation due to its accessibility and clinical relevance. A conventional nerve cuff electrode is the least invasive method for nerve stimulation, but the mismatch of mechanical properties of the electrode with the nerve tissue can cause damage to the nerve and the electrode itself. This study investigated a novel bipolar, gold nanowire-based cuff electrode design and its ability to selectively activate fibers in the rat sciatic nerve at varying interelectrode spacings. In COMSOL, A finite element model (FEM) of a simplified rat sciatic nerve was developed to simulate the electric field along the length of the nerve. Electrode spacing was varied from 1 mm to 4 mm in 0.25 mm increments, and pulse amplitudes ranged from 25 µA to 150 µA. The scalar electric potentials derived from the model were used in a linear cable model implemented in MATLAB to determine injected current and smallest activated fiber diameters across four fascicles and 36 test locations. Results showed that electrode spacing significantly influenced nerve fiber activation at pulse amplitudes of 75 µA and 150 µA (p < 0.05). Wider spacings resulted in higher extracellular voltages at fascicle centers, reducing activation thresholds for smaller fibers. Fascicle location relative to the electrode also influenced activated fiber diameter, with fascicles closer to the epineurium activating smaller fibers more easily. This study demonstrates the value of computational modeling in guiding electrode design and lays the groundwork for future development of patient-specific or application-specific nerve interfaces.

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