Next Article in Journal
Biocompatible Hydrogels for Microarray Cell Printing and Encapsulation
Next Article in Special Issue
Computational Assessment of Neural Probe and Brain Tissue Interface under Transient Motion
Previous Article in Journal
Introduction to Special Issue on “Fluorescence-Based Sensing Technologies”
Article Menu

Export Article

Open AccessArticle
Biosensors 2015, 5(4), 618-646;

In Vivo Electrochemical Analysis of a PEDOT/MWCNT Neural Electrode Coating

Department of Bioengineering, University of Pittsburgh, 5056 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15213, USA
Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15260, USA
McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA
NeuroTech Center of the University of Pittsburgh Brain Institute, Pittsburgh, PA 15260, USA
Author to whom correspondence should be addressed.
Academic Editor: Hargsoon Yoon
Received: 18 August 2015 / Revised: 23 September 2015 / Accepted: 30 September 2015 / Published: 13 October 2015
(This article belongs to the Special Issue Neural Sensing and Interfacing Technology)
Full-Text   |   PDF [1528 KB, uploaded 13 October 2015]   |  


Neural electrodes hold tremendous potential for improving understanding of brain function and restoring lost neurological functions. Multi-walled carbon nanotube (MWCNT) and dexamethasone (Dex)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) coatings have shown promise to improve chronic neural electrode performance. Here, we employ electrochemical techniques to characterize the coating in vivo. Coated and uncoated electrode arrays were implanted into rat visual cortex and subjected to daily cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) for 11 days. Coated electrodes experienced a significant decrease in 1 kHz impedance within the first two days of implantation followed by an increase between days 4 and 7. Equivalent circuit analysis showed that the impedance increase is the result of surface capacitance reduction, likely due to protein and cellular processes encapsulating the porous coating. Coating’s charge storage capacity remained consistently higher than uncoated electrodes, demonstrating its in vivo electrochemical stability. To decouple the PEDOT/MWCNT material property changes from the tissue response, in vitro characterization was conducted by soaking the coated electrodes in PBS for 11 days. Some coated electrodes exhibited steady impedance while others exhibiting large increases associated with large decreases in charge storage capacity suggesting delamination in PBS. This was not observed in vivo, as scanning electron microscopy of explants verified the integrity of the coating with no sign of delamination or cracking. Despite the impedance increase, coated electrodes successfully recorded neural activity throughout the implantation period. View Full-Text
Keywords: interface; neural prosthesis; drug release; controlled drug release; electroactive polymer; nanocomposite interface; neural prosthesis; drug release; controlled drug release; electroactive polymer; nanocomposite

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Alba, N.A.; Du, Z.J.; Catt, K.A.; Kozai, T.D.Y.; Cui, X.T. In Vivo Electrochemical Analysis of a PEDOT/MWCNT Neural Electrode Coating. Biosensors 2015, 5, 618-646.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Biosensors EISSN 2079-6374 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top