Highly Stable PEDOT:PSS Coating on Gold Microelectrodes with Improved Charge Injection Capacity for Chronic Neural Stimulation

Abstract

This study introduces two new processes that highly enable PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) as stable coating material for chronic neural stimulation. In first process, strong mechanical bonding between PEDOT:PSS coating and gold electrodes is achieved by creating rough porous surface with partial iodine etching. PEDOT:PSS coating on iodine etched gold electrode shows 100% stability under strong ultrasonic treatment. The second process represents electrochemical modification of PEDOT:PSS coating by cyclic voltammetry method in Ringer’s solution. This process reduces electrode polarization 33% during stimulation. Therefore, charge injection capacity increases that ensures safe stimulation. A combination of both processes facilitates the use of PEDOT:PSS coating for successful chronic neural recording and stimulation.

Keywords

• PEDOT:PSS
• iodine etching
• chronic neural stimulation
• neural interfaces
• long-term stability