Design, Characterization, and In Vivo Application of Multi-Conductive Layer Organic Electrocorticography Probes

Rémy Cornuéjols (1, 2) , Amélie Albon (2) , Suyash Joshi (3) , James Alexander Taylor (3) , Martin Baca (2) , Sofia Drakopoulou (2) , Tania Rinaldi Barkat (3) , Christophe Bernard (1) , Shahab Rezaei-Mazinani (2)

1 INS - Institut de Neurosciences des Systèmes
2 Department of Bioelectronics
3 Department of Biomedicine [Basel]

Biocompatible and plastic neural interface devices allow for minimally invasive recording of brain activity. Increasing electrode density in such devices is essential for high resolution neural recordings. Superimposing conductive leads in devices can help multiplying the number of recording sites while keeping probes width small and suitable for implantation. However, because of leads' vertical proximity, this can create capacitive coupling (CC) between overlapping channels, which leads to crosstalk. Here, we present a thorough investigation of CC phenomenon in multi gold layer thin-film multi-electrode arrays (MEA) with a Parylene C (PaC) insulation layer 2 between superimposed leads. We also propose a guideline on the design, fabrication and characterization of such type of neural interface devices for high spatial resolution recording. Our results demonstrate that the capacitance created through CC between superimposed tracks decreases non-linearly then linearly with the increase of insulation thickness. We identify an optimal PaC insulation thickness that leads to a drastic reduction of CC between superimposed gold channels, while not significantly increasing the overall device thickness. Finally, we show that double gold layer ECoG probes with the optimal insulation thickness exhibit similar performances in vivo when compared to single layer devices. This confirms that these probes are adequate for high-quality neural recordings.

Mots clés: neural interface devices; capacitive couplings; crosstalks; bioelectronics; neural recordings; thin-film polymers; microelectrode arrays

Domaines: Biotechnologie; Science des matériaux [cond-mat.mtrl-sci]; Electronique

Rémy Cornuéjols, Amélie Albon, Suyash Joshi, James Alexander Taylor, Martin Baca, et al.. Design, Characterization, and In Vivo Application of Multi-Conductive Layer Organic Electrocorticography Probes. 2023. ⟨hal-04476122⟩