A Novel Rapidly Manufacturable Flexible Subdural Electrode Array for Intraoperative Mapping of Cortical Activity

Abstract

Flexible and biocompatible neurointerfaces are crucial elements for intraoperative monitoring and chronic neural recordings. However, existing fabrication methods often involve complex cleanroom processes, limiting rapid prototyping and customization. In this study, we present a fast, low-cost method for manufacturing a flexible subdural electrode array based on polydimethylsiloxane (PDMS) and gold conductive layer. The fabrication process utilizes a laser cutter for both mask generation and direct patterning of metal traces on a PDMS substrate, achieving a resolution of up to 30 {micro}m. A detachable interface was developed for reliable connectivity during testing. The electrochemical and mechanical properties of the array were characterized, demonstrating Ohmic behavior and stable conductivity after 50 cycles of mechanical bending, with a degradation of less than 10%. Electrochemical impedance spectroscopy (EIS) confirmed the viability of the electrodes for recording physiological signals. The functionality of the array was validated in vivo by performing simultaneous recordings of local field potentials (LFPs) and electrocorticography (ECoG) in the rat somatosensory cortex. The signals from the flexible subdural array showed a statistically significant (p < 0.001) median cross-correlation of 0.35 with LFPs recorded at a depth of 600-800 {micro}m by industrial electrode. We demonstrate here a robust and accessible approach for producing functional neural interfaces, suitable for rapid iteration and customization in research and clinical applications.