3D Cone-Shape Carbon Electrode Array for High-Fidelity Ecog Acquisition

This work presents a three-dimensional cone-shaped carbon neural electrode array that achieves non-invasive, self-adaptive contact with the cortical surface. Using the ultraviolet laser processing, 3D conical microelectrodes and interconnects are patterned directly on a soft PDMS substrate, forming a conformal, mechanically compliant interface that enhances electrocorticography (ECoG) quality. The precise control of laser parameters enables tuning of cone height, thereby modulating cathodic charge storage capacity and impedance by multiple folds. To assess in vivo performance, 2D and 3D electrodes were implanted in the contralateral primary motor cortex (M1) of a rabbit and recorded simultaneously using a dual-array acquisition system. The 16-ch 3D electrodes exhibited impedance up to two orders of magnitude lower than that of 2D electrodes, together with higher amplitudes and reduced inter-trial variability. This soft 3D carbon electrode array provides a tissue-matched neural interface for robust, high-fidelity ECoG acquisition.