There is continued interest in the development of conductive polymer coatings to improve the electrical properties and biocompatibility of electrodes for neural prostheses. We present here a new type of coating, based on mixed self-assembled monolayers (SAMs) of thiolated poly(alkylthiophene)s and functionalized alkanethiols. When assembled as a SAM on electrodes designed for in vitro electrophysiology, these polymers are able to significantly lower electrode impedance at 1 kHz. The same mixed formulation is able to promote the outgrowth of neurites from primary mouse cortical neurons when the alkanethiol component is functionalized with a neural cell adhesion molecule (NCAM) binding antibody. Atomic force microscopy of the SAMs shows that they exert their effect through the well-known mechanism of increasing electrode surface area. These new covalently bound films have the potential to be more robust and are more controllable in their composition than existing electrodeposited conductive polymer coatings.
Bibliographical noteFunding Information:
Mr. Widge was funded during the course of this work by a National Defense Science & Engineering Graduate Fellowship and by an individual National Research Service Award fellowship from the National Institute of Neurological Disorders & Stroke. Further support was provided by a seed grant from the American Medical Association Foundation. Ms. Mengyao Zhe of Carnegie Mellon University designed and constructed the custom connector for impedance measurement of multielectrode arrays. Preliminary impedance data were also collected by both Ms. Zhe and Ms. Megan Tzeng, also of Carnegie Mellon. Finally, we thank Dr. James Schneider of the Chemical Engineering Department at Carnegie Mellon for many helpful discussions and the use of multiple pieces of equipment within his laboratory.
- Conducting polymer
- Neural interface
- Neural prosthesis
- Self-assembled monolayer