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

Area of Science:

• Neuroscience
• Materials Science
• Electrical Engineering

Background:

• Biocompatible neural interfaces are crucial for minimally invasive brain activity recording.
• Increasing electrode density is key for high-resolution neural recordings.
• Superimposed conductive leads can increase recording sites but risk capacitive coupling (CC) and crosstalk.

Purpose of the Study:

• To investigate capacitive coupling in multi-gold layer thin-film multi-electrode arrays.
• To propose design and fabrication guidelines for high spatial resolution neural interfaces.
• To identify optimal insulation thickness for minimizing CC.

Main Methods:

• Fabrication of multi-gold layer thin-film multi-electrode arrays with parylene C (PaC) insulation.
• Characterization of capacitive coupling as a function of insulation thickness.
• In vivo performance comparison of double-layer and single-layer electrocorticography probes.

Main Results:

• Capacitance due to CC decreased non-linearly and then linearly with increasing insulation thickness.
• An optimal PaC insulation thickness was identified, significantly reducing CC without substantial device thickening.
• Double gold layer probes with optimal insulation showed comparable in vivo performance to single-layer devices.

Conclusions:

• Optimized insulation thickness effectively mitigates capacitive coupling in multi-layer neural probes.
• These findings provide guidelines for designing high-density neural interfaces for high-quality recordings.
• Multi-layer electrode arrays with optimized insulation are suitable for advanced neural recording applications.