Nanocone-Array-Based Platinum-Iridium Oxide Neural Microelectrodes: Structure, Electrochemistry, Durability and...

Area of Science:

• Neuroscience
• Materials Science
• Biomedical Engineering

Background:

• Neural microelectrodes are crucial for bio-signal modulation and recording.
• Miniaturization of electrodes leads to high impedance and low capacitance, limiting performance.
• Need for stable, low-power neural interfaces.

Purpose of the Study:

• To develop high-performance neural microelectrodes with enhanced surface area and conductivity.
• To address limitations of small-sized electrodes in neural interfaces.
• To improve stimulation and recording efficiency for neural applications.

Main Methods:

• Fabrication of nanocone-shaped platinum (Pt) as an adhesive layer on a Pt substrate.
• Deposition of iridium oxide (IrO_x) to create Pt-IrO_x nanocomposite microelectrodes.
• Characterization of electrochemical properties, including impedance, charge storage capacity (CSC_c), and charge injection capacity (CIC).

Main Results:

• Achieved significantly low impedance (0.72 ± 0.04 Ω cm² at 1 kHz), a ~92.95% reduction.
• High cathodic charge storage capacity (CSC_c) of 52.44 ± 2.53 mC cm^-2 and charge injection capacity (CIC) of 4.39 ± 0.36 mC cm^-2.
• Demonstrated superior chronic stability, biocompatibility, and enhanced microglia adhesion.

Conclusions:

• The developed Pt-IrO_x nanocone-array microelectrodes offer a promising solution for high-performance neural interfaces.
• The fabrication method is scalable for multichannel flexible microelectrode arrays (fMEAs).
• This strategy holds significant potential for biomedical applications and advanced neural recording/stimulation systems.