Facile Deep Brain Electrode Coating with MXene for Improved Electrode Performance.

Abstract

Accurate brain signal recording and precise electrode placement are critical for the success of neuromodulation therapies such as deep brain stimulation (DBS). Addressing these challenges requires deep brain electrodes that provide high-quality, stable recordings while remaining compatible with high-resolution medical imaging modalities like magnetic resonance imaging (MRI). Moreover, such electrodes shall be cost-effective, easy to manufacture, and patient-compatible. In this study, a facile dip-coating approach is proposed using conductive titanium carbide (Ti₃C₂T_x) MXene nanosheets to enhance the performance of commercially available carbon fiber electrodes for chronic neural recording. Ti₃C₂T_x-coated electrodes exhibit improved electrical conductivity, environmental and mechanical stabilities, reduced and stable impedance, and enhanced charge storage and injection capacity compared to uncoated carbon electrodes. When implanted in the rat dorsal hippocampal CA1 region, Ti₃C₂T_x electrodes exhibited significantly lower impedance over 4 weeks, reduced susceptibility to 60 Hz line noise, and the capability to detect single-unit neuronal activity-features not observed in uncoated controls. Notably, the Ti₃C₂T_x coating does not induce inflammation at the implantation sites, and remained fully MRI-compatible, unlike tungsten electrodes. These findings offer a straightforward and practical solution for achieving high-quality chronic deep brain electrophysiology recordings while maintaining biocompatibility, safety, cost-effectiveness, and MRI compatibility.