A Conformable Linear Electrode Platform for Impedance Mapping of Soft Tissue Interfaces

Abstract

Soft electrode arrays capable of conforming to complex anatomical surfaces are vital for emerging biomedical sensing technologies. They are particularly relevant in applications requiring large-area, high-resolution mapping. Reducing the time required for such mapping is critical to minimize overall procedure duration and improve clinical efficiency. However, the electrical performance of such systems under mechanical deformation remains poorly understood. This thesis presents a novel soft electrode line architecture for large-area sensing on non-planar surfaces inspired by the contours of the natural human anatomy. The system features a modular structure of alternating copper electrodes and silicone tubing, internally bridged by stainless steel wires—enabling geometric adaptability and electrical continuity while maintaining a manufacturable, low-profile form factor. Mechanical modeling revealed that internal wires dominate flexural stiffness, limiting curvature before exceeding physiological force thresholds or inducing plastic deformation. These constraints guided the design of conductive tissue-phantoms for impedance testing under realistic curvature and pressure. Electrochemical impedance spectroscopy (EIS) was used to assess performance across four representative geometries and loading states. Results showed that curvature increased impedance and reduced capacitive response due to diminished double-layer formation and altered field distribution, while pressure improved contact and lowered impedance. Equivalent circuit modeling captured the dominant spectral trends across geometries and enabled systematic comparison of how geometry affects interfacial and bulk electrical properties, revealing consistent trade-offs between contact uniformity and field confinement. Together, these results establish a blueprint for embedding deformable electrodes in constrained biological environments without sacrificing signal fidelity. The insights gained offer valuable design guidance for future systems requiring both mechanical adaptability and electrochemical reliability, and lay the groundwork for next-generation conformable biosensing platforms.