title: In vitro and in vivo evaluation of PEDOT microelectrodes for neural stimulation and recording.
abstract: Cortical neural prostheses require chronically implanted small-area microelectrode arrays that simultaneously record and stimulate neural activity. It is necessary to develop new materials with low interface impedance and large charge transfer capacity for this application and we explore the use of conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) for the same. We subjected PEDOT coated electrodes to voltage cycling between -0.6 and 0.8 V, 24 h continuous biphasic stimulation at 3 mC/cm² and accelerated aging for four weeks. Characterization was performed using cyclic voltammetry, electrochemical impedance spectroscopy, and voltage transient measurements. We found that PEDOT coated electrodes showed a charge injection limit 15 times higher than Platinum Iridium (PtIr) electrodes and electroplated Iridium Oxide (IrOx) electrodes when using constant current stimulation at zero voltage bias. In vivo chronic testing of microelectrode arrays implanted in rat cortex revealed that PEDOT coated electrodes show higher signal-to-noise recordings and superior charge injection compared to PtIr electrodes.
authors.affiliation: Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA.
authors.forename: Subramaniam
authors.initials: S
authors.lastname: Venkatraman
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Hendricks
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: King
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Sereno
authors.forename: Sarah
authors.initials: S
authors.lastname: Richardson-Burns
authors.forename: David
authors.initials: D
authors.lastname: Martin
authors.forename: Jose M
authors.initials: JM
authors.lastname: Carmena
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D004558:Electric Stimulation / Q000295:instrumentation*; D004566:Electrodes; D004567:Electrodes, Implanted; D004581:Electronics; D005260:Female; D007495:Iridium / Q000737:chemistry; D008839:Microelectrodes; D058117:Neural Prostheses; D009474:Neurons / Q000502:physiology*; D011108:Polymers / Q000737:chemistry*; D011474:Prosthesis Design; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D011108:Polymers; C121383:poly(3,4-ethylene dioxythiophene); C044458:iridium oxide; D007495:Iridium