Intracranial, Subcutaneous and Scalp Electroencephalography with Multiscale Arrays Based on 2D MXenes

Electroencephalography (EEG) is commonly used for neurological diagnostics and monitoring, and in neuroscience research. Depending on the application and degree of invasiveness, EEG can be acquired with gelled electrodes placed on the scalp or invasively with intracranial electrodes. Recently, subcutaneous EEG has emerged as a minimally invasive, mobile, and reliable alternative solution for long-term epilepsy monitoring and seizure forecasting.<br/>In this talk I will present multiscale arrays for intracranial, subcutaneous, and scalp EEG based on high-throughput liquid-phase processing of 2D Ti₃C₂T<i>_x</i> MXene. Leveraging the colloidal stability of MXenes in aqueous dispersions, we have developed a rapid fabrication process to produce EEG arrays with fully customizable geometry, scale, and density. For scalp EEG, the devices feature 3D pillars of varying diameter and height fabricated from PVA aerogel templates infiltrated with Ti₃C₂T<i>_x</i>. Due to the high electrical conductivity (155 ± 4 Ω, n= 5), porosity, and surface area, these 3D electrodes can establish a low impedance interface with the scalp without the need for any gel or conductive adhesive (10 Hz impedance of 8 mm pillar electrodes: 2.1 ± 1.8 kΩ, n=5 participants).<br/>To illustrate examples of applications of these multiscale MXene EEG arrays, I will present our most recent studies on intraoperative recordings in large animals and humans, longitudinal monitoring of post-traumatic epilepsy evolution with subcutaneous EEG in murine models, and clinical scalp EEG in epilepsy patients.