Improving the performance of poly(3,4-ethylenedioxythiophene) for brain-machine interface applications

Himadri S Mandal; Gretchen L Knaack; Hamid Charkhkar; Daniel G McHail; Jemika S Kastee; Theodore C Dumas; Nathalia Peixoto; Judith F Rubinson; Joseph J Pancrazio

doi:10.1016/j.actbio.2014.02.029

Improving the performance of poly(3,4-ethylenedioxythiophene) for brain-machine interface applications

Acta Biomater. 2014 Jun;10(6):2446-54. doi: 10.1016/j.actbio.2014.02.029. Epub 2014 Feb 24.

Authors

Himadri S Mandal¹, Gretchen L Knaack², Hamid Charkhkar³, Daniel G McHail², Jemika S Kastee⁴, Theodore C Dumas², Nathalia Peixoto³, Judith F Rubinson⁵, Joseph J Pancrazio⁶

Affiliations

¹ Department of Bioengineering, George Mason University, Fairfax, VA 22030, USA. Electronic address: hmandal@gmu.edu.
² Department of Molecular Neuroscience, The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA 22030, USA.
³ Department of Electrical and Computer Engineering, George Mason University, Fairfax, VA 22030, USA.
⁴ Department of Bioengineering, George Mason University, Fairfax, VA 22030, USA.
⁵ Department of Chemistry, Georgetown University, Washington, DC 20057, USA.
⁶ Department of Bioengineering, George Mason University, Fairfax, VA 22030, USA; Department of Electrical and Computer Engineering, George Mason University, Fairfax, VA 22030, USA.

PMID: 24576579
DOI: 10.1016/j.actbio.2014.02.029

Abstract

Conducting polymers, especially poly(3,4-ethylenedioxythiophene) (PEDOT) based materials, are important for developing highly sensitive and microscale neural probes. In the present work, we show that the conductivity and stability of PEDOT can be significantly increased by switching the widely used counter anion poly(styrenesulfonate) (PSS) to the smaller tetrafluoroborate (TFB) anion during the electrodeposition of the polymer. Time-dependent impedance measurements of polymer modified implantable microwires were conducted in physiological buffer solutions under accelerated aging conditions and the relative stability of PEDOT:PSS and PEDOT:TFB modified microwires was compared over time. This study was also extended to carbon nanotube (CNT) incorporated PEDOT:PSS which, according to some reports, is claimed to enhance the stability and electrical performance of the polymer. However, no noticeable difference was observed between PEDOT:PSS and CNT:PEDOT:PSS in our measurements. At the biologically relevant frequency of 1kHz, PEDOT:TFB modified microwires exhibit approximately one order of magnitude higher conductivity and demonstrate enhanced stability over both PEDOT:PSS and CNT:PEDOT:PSS modified microwires. In addition, PEDOT:TFB is not neurotoxic and we show the proof-of-concept for both in vitro and in vivo neuronal recordings using PEDOT:TFB modified microelectrode arrays and chronic electrodes, respectively. Our findings suggest that PEDOT:TFB is a promising conductive polymer coating for the recording of neural activities.

Keywords: Action potential; Carbon nanotube; Electrochemical impedance; Neural probe; PEDOT.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Brain-Computer Interfaces*
Bridged Bicyclo Compounds, Heterocyclic / chemistry*
Microscopy, Electron, Scanning
Polymers / chemistry*

Substances

Bridged Bicyclo Compounds, Heterocyclic
Polymers
poly(3,4-ethylene dioxythiophene)