Multilayer Graphene Based MRI Compatible MEMS Neural Probes for both Stimulation and Recording

Area of Science:

• Bioelectronics
• Materials Science
• Neuroscience

Background:

• Conventional metallic neural probes cause MRI artifacts and thermal risks.
• Advancing functional neuroimaging requires improved neural interface materials.

Purpose of the Study:

• To develop a metal-free neural probe for MRI-integrated applications.
• To enhance electrochemical performance and biocompatibility for neural recording.

Main Methods:

• Fabrication of multilayer graphene (MLG) neural probes using spin-spray deposition on polyimide.
• Characterization of electrochemical properties (charge storage capacity, injection limit) and mechanical properties (Young's modulus).
• Evaluation of MRI compatibility (susceptibility artifacts, RF-induced heating) and long-term in vivo performance in mouse hippocampus.

Main Results:

• MLG probes demonstrated significantly higher charge storage capacity and injection limits compared to gold electrodes.
• Probes exhibited minimal MRI artifacts and RF-induced heating (<0.4 °C at 9.4 T).
• Stable electrophysiological performance was maintained for six months in vivo with low impedance drift.

Conclusions:

• The MLG neural probe offers superior electrochemical efficacy and MRI compatibility.
• This metal-free probe is a promising tool for advanced MRI-integrated neural interfaces.
• Graphene-based materials hold significant potential for future bioelectronic applications.