Poster Z18 - Inkjet-Printed, Flexible Organic Electrochemical Transistors for High-fedility Electrocorticography Recordings

Introduction: Organic Electrochemical Transistors (OECTs) have become critical in bio-signal amplification, particularly in electrocorticography (ECoG) applications. Traditional fabrication methods for high-performance OECTs involve complex, costly, and environmentally taxing processes. This study presents a novel approach to developing OECT devices through a streamlined, cost-effective, and eco-friendly inkjet printing method, significantly enhancing ECoG recording capabilities and making these devices more accessible for clinical and research applications.

Materials and

Methods: We utilized a three-step Drop-on-Demand (DoD) inkjet printing process on flexible polyimide substrates to fabricate the OECT devices. Gold nanoparticle ink was used for patterning terminals, polyimide ink for insulation, and PEDOT:PSS for the semiconducting channel. Device characterization involved electrical measurements using Source Measure Units (SMUs) to obtain I-V curves, transfer characteristics, and response times. Electrochemical performance was evaluated through cyclic voltammetry and impedance spectroscopy. In vivo evaluations were conducted using a rat model of seizure, with the OECT devices implanted for electrocorticographic recordings, allowing for direct comparison with conventional electrodes.

Results, Conclusions, and Discussions: The fabricated OECT devices demonstrated a rapid response time of 0.5 ms, a compact channel area of 1950 µm², and a high transconductance of 11 mS. In vivo tests showed high-fidelity recording of seizure phases with an SNR improvement of up to 133% over traditional PEDOT:PSS coated gold electrodes, achieving a peak SNR of 48 dB. The devices maintained stable performance under mechanical stress, with minimal degradation after 100 bending and twisting cycles, and exhibited consistent electrical characteristics in solution over extended periods, underscoring their durability and reliability for long-term use.

Acknowledgements (Optional):