Electrochemical polymerization of poly(hydroxymethylated-3,4-ethylenedioxythiophene) (PEDOT-MeOH) on multichannel neural probes
By Yoshida, Takamitsu; Terashima, Nobuyoshi; Niiro, Toru; Nagasawa, Sakae; Ito, Michio; Yagasaki, Hiroshi; Oshida, Yoshiki & Agarwal, Parul
Published in Sensors and Actuators B: Chemical
2004
Abstract
Electrochemical polymerization of a derivative of 3,4-ethylenedioxythiophene (EDOT), specifically hydroxymethylated EDOT (EDOT-MeOH) which exhibits higher solubility in water than EDOT, was used to modify the surface of gold microfabricated neural probes. Films of varied thickness of the conducting form of PEDOT-MeOH doped with poly(styrene sulfonate) (PSS) were deposited on the surface of the electrodes using different electropolymerization times. Scanning electron microscope (SEM) images revealed that the surface of PEDOT-MeOH/PSS had a rough and nodular morphology which lowered the impedance of the coated electrode over a wide range of frequencies from 100 to 105 Hz. At the biologically relevant frequency of 1 kHz, the lowest impedance magnitude was 10 kΩ. Cyclic voltammetry (CV) demonstrated the intrinsic redox reaction and the increased charge capacity of PEDOT-MeOH/PSS coated electrodes relative to the bare gold electrodes. PEDOT-MeOH doped with the biologically active nonapeptide CDPGYIGSR was also successfully deposited onto the electrodes to attain adherent and uniform coatings.