Benchmarking the Performance of Electropolymerized Poly(3,4‐ethylenedioxythiophene) Electrodes for Neural Interfacing

• Published in: Macromolecular bioscience Vol. 20; no. 11; pp. e2000215 - n/a
• Main Authors: Nikiforidis, Georgios, Wustoni, Shofarul, Routier, Cyril, Hama, Adel, Koklu, Anil, Saleh, Abdulelah, Steiner, Nadia, Druet, Victor, Fiumelli, Hubert, Inal, Sahika
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.11.2020
• Subjects: Additives; Anions; Aqueous solutions; Capacitance; Charge injection; conducting polymer; Conducting polymers; Copolymers; Electrochemical analysis; Electrochemistry; Electrodes; Electronic materials; electropolymerization; Ethylene glycol; Interface stability; microelectrode array; Microelectrodes; Nervous system; Neural networks; neuronal interface; Perchlorate; Perchloric acid; poly(3,4‐ethylenedioxythiophene); Polymers
• ISSN: 1616-5187; 1616-5195
• DOI: 10.1002/mabi.202000215

The development of electronics adept at interfacing with the nervous system is an ever‐growing effort, leading to discoveries in fundamental neuroscience applied in clinical setting. Highly capacitive and electrochemically stable electronic materials are paramount for these advances. A systematic study is presented where copolymers based on 3,4‐ethylenedioxythiophene (EDOT) and its hydroxyl‐terminated counterpart (EDOTOH) are electropolymerized in an aqueous solution in the presence of various counter anions and additives. Amongst the conducting materials developed, the copolymer p(EDOT‐ran‐EDOTOH) doped with perchlorate in the presence of ethylene glycol shows high specific capacitance (105 F g−1), and capacitance retention (85%) over 1000 galvanostatic charge–discharge cycles. A microelectrode array‐based on this material is fabricated and primary cortical neurons are cultured therein for several days. The microelectrodes electrically stimulate targeted neuronal networks and record their activity with high signal‐to‐noise ratio. The stability of charge injection capacity of the material is validated via long‐term pulsing experiments. While providing insights on the effect of additives and dopants on the electrochemical performance and operational stability of electropolymerized conducting polymers, this study highlights the importance of high capacitance accompanied with stability to achieve high performance electrodes for biological interfacing. This study provides insights on the effect of additives and dopants on the electrochemical performance and operational stability of electropolymerized conducting polymers based on 3,4‐ethylenedioxythiophene and its hydroxyl‐terminated counterpart in aqueous electrolytes. It highlights the importance of high capacitance accompanied by stability to achieve high‐performance electrodes at biological interfaces and for sensing and triggering neural signals.