Electropolymerized Poly(3,4-ethylenedioxythiophene) (PEDOT) Coatings for Implantable Deep-Brain-Stimulating...

Area of Science:

• Biomaterials Science
• Neurotechnology
• Electrochemistry

Background:

• Conducting polymers enhance neural electrode performance through mixed electronic-ionic conduction and biocompatibility.
• Poly(3,4-ethylenedioxythiophene) (PEDOT) offers high conductivity and electrochemical stability, making it ideal for biomedical uses.
• Existing PEDOT coatings face challenges with delamination and stability, limiting device lifespan.

Purpose of the Study:

• To electropolymerize stable poly(3,4-ethylenedioxythiophene) (PEDOT) coatings on platinum-iridium neural electrodes.
• To evaluate the mechanical and electrochemical stability of PEDOT coatings in various conditions.
• To assess the in vivo performance of PEDOT-coated electrodes for neural stimulation.

Main Methods:

• Electropolymerization of PEDOT:tetrafluoroborate in propylene carbonate, acetonitrile, and water.
• Coating stability assessment through ultrasonication, soaking, autoclave sterilization, and electrical pulsing.
• In vivo implantation and daily electrical stimulation of microelectrodes in rats for 7 and 15 days.

Main Results:

• PEDOT coatings electropolymerized in propylene carbonate or acetonitrile demonstrated excellent electrochemical stability.
• Coatings successfully withstood autoclave sterilization, prolonged soaking, and electrical stimulation without significant property changes.
• In vivo monitoring showed that electrical stimulation reduced impedance for both coated and uncoated electrodes.

Conclusions:

• Electropolymerized PEDOT coatings, particularly those from propylene carbonate or acetonitrile, offer robust mechanical and electrochemical stability for neural electrodes.
• These stable PEDOT coatings are suitable for neural recording and stimulation applications, addressing previous limitations of delamination and instability.
• The study demonstrates the potential of stable PEDOT coatings to enhance the performance and longevity of neural devices.