Amorphous Silicon Carbide Platform for Next Generation Penetrating Neural Interface Designs

Area of Science:

• Neuroscience
• Materials Science
• Biomedical Engineering

Background:

• Chronic implantation of microelectrode arrays for neural recording and stimulation faces challenges from biotic and abiotic failures.
• Thin arrays (≤10 µm) reduce inflammation but are prone to buckling, necessitating protective insertion shuttles that can cause damage.

Purpose of the Study:

• To investigate amorphous silicon carbide (a-SiC) as a material for fabricating ultrasmall, mechanically robust microelectrode arrays.
• To assess the performance of a-SiC implants in penetrating cortical tissue and recording neural activity without structural support.

Main Methods:

• Fabrication of prototype a-SiC intracortical implants with 8-16 shanks at critical thicknesses of 4 µm or 6 µm.
• Evaluation of the mechanical properties, specifically buckling resistance, of the a-SiC shanks.
• In vivo testing of 6 µm thick a-SiC shanks for cortical penetration in rats without insertion aids.
• Recording of single unit neural activity using Surface-而不是-Insulator-Oxide-Resonance-Field (SIROF)-coated arrays.

Main Results:

• a-SiC demonstrated excellent electrical insulation and a high Young's modulus, enabling ultrasmall array fabrication.
• 6 µm thick a-SiC shanks successfully penetrated rat cortex without requiring an insertion shuttle.
• Single unit neural recordings were achieved with arrays implanted without structural support, validating the material's suitability.

Conclusions:

• Amorphous silicon carbide is a promising material for developing mechanically stable, ultrasmall microelectrode arrays for neural interfaces.
• The developed a-SiC implants overcome the trade-off between thinness for reduced inflammation and mechanical robustness.
• This technology advances the potential for reliable, chronic neural recording and stimulation with minimal tissue damage.