Electrochemical characteristics of microelectrode designed for electrical stimulation

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Microelectrode arrays are crucial for neural prosthetics, requiring safety and reliability for signal recording and stimulation.
• Flexible substrates like parylene-C enhance tissue compliance and signal stability in neural implants.
• Minimizing tissue damage and maintaining stable electrical contact are key challenges in neural interface design.

Purpose of the Study:

• To design and fabricate a flexible microelectrode array using gold electrodes and a parylene-C substrate.
• To evaluate the in vitro electrochemical characteristics and charge injection capacity of the fabricated microelectrode array.
• To assess the potential of this flexible microelectrode array for neurological signal acquisition and neurostimulation.

Main Methods:

• Fabrication of a flexible microelectrode array with gold electrodes and parylene-C substrate.
• In vitro electrochemical characterization using electrochemical impedance spectroscopy and cyclic voltammetry in phosphate-buffered saline.
• Charge injection capacity measurements using multichannel systems to calculate the charge injection capacity (CIC).

Main Results:

• The microelectrode array exhibited decreasing impedance with increasing frequency, with an average impedance of 36.54 ± 0.88 kΩ at 1 kHz.
• The average phase angle at 1 kHz was -73.52 ± 1.3°, and the charge injection capacity (CIC) was 22.3 µC/cm².
• Electrochemical results confirmed the array's suitability for neuronal signal recording and stimulation applications.

Conclusions:

• The parylene-C substrate provides good flexibility, and the gold electrodes demonstrate resistance to corrosion and good biocompatibility.
• The fabricated flexible microelectrode array shows significant potential for implantable neurological signal acquisition and neurostimulation.
• This low-cost, flexible, parylene-based, gold microelectrode array offers a promising solution for advanced neural interface applications.