Freeze Drying Improves the Shelf-Life of Conductive Polymer Modified Neural Electrodes

Bioengineering

Himadri S. Mandal¹  Richard O. Cliff³  Joseph J. Pancrazio² 

[1] Blackrock Microsystems, 630 Komas Dr #200, Salt Lake City, UT 84108, USA;Department of Bioengineering, Volgenau School of Engineering, George Mason University, 4400 University Drive, MS 1G5, Fairfax, VA 22030, USA; E-Mail:;System of Systems Analytics, 11250 Waples Mill Road, Fairfax, VA 22030, USA; E-Mail:

关键词: conductive polymer;    PEDOT;    microwires;    impedance;    neural electrode;   

DOI  :  10.3390/bioengineering2030176

来源: mdpi

【 摘 要 】

Coating microelectrodes with conductive polymer is widely recognized to decrease impedance and improve performance of implantable neural devices during recording and stimulation. A concern for wide-spread use of this approach is shelf-life, i.e., the electrochemical stability of the coated microelectrodes prior to use. In this work, we investigated the possibility of using the freeze-drying process in order to retain the native low impedance state and, thereby, improve the shelf-life of conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT)-PSS modified neural electrodes. Control PEDOT-PSS coated microelectrodes demonstrated a significant increase in impedance at 1 kHz after 41–50 days of room temperature storage. Based on equivalent circuit modeling derived from electrochemical impedance spectroscopy, this increase in impedance could be largely attributed to a decrease in the interfacial capacitance consistent with a collapse and closing of the porous structure of the polymeric coating. Time-dependent electrochemical impedance measurements revealed higher stability of the freeze-dried coated microelectrodes compared to the controls, such that impedance values after 41–50 days appeared to be indistinguishable from the initial levels. This suggests that freeze drying PEDOT-PSS coated microelectrodes correlates with enhanced electrochemical stability during shelf storage.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.