Soft Neural Interfacing based on Implantable Graphene Fiber Microelectrode Arrays

Area of Science:

• Neuroscience
• Materials Science
• Biomedical Engineering

Background:

• Microelectrode Arrays (MEAs) are crucial for neural interfaces, monitoring and modulating brain activity.
• Graphene's properties (high conductance, large surface-to-volume ratio, biocompatibility, flexibility) make it ideal for advanced neural interface design.
• Current neural interfaces face challenges that graphene-based materials can potentially overcome.

Purpose of the Study:

• To fabricate and characterize flexible, ultrasmall, implantable neurostimulators using graphene fibers.
• To explore the potential of graphene fibers as a replacement for conventional electrodes in neural prostheses.
• To demonstrate a method for creating custom-sized and multi-channel flexible MEAs.

Main Methods:

• Graphene fibers (10-50 µm diameter) were produced using wet-spinning.
• A 10-channel polyimide Printed Circuit Board (PCB) was custom-designed and manufactured.
• Fibers were attached to the PCB with conductive glue, insulated with polyurethane, and tips exposed.
• Microstructure was analyzed using Scanning Electron Microscopy (SEM); electrode performance was measured via Electrochemical Impedance Spectroscopy (EIS).

Main Results:

• Flexible MEAs were successfully fabricated using graphene fibers (10-50 µm diameter) with 150 µm spacing.
• The fabrication method allows for variable fiber sizes and channel numbers.
• SEM and EIS confirmed the microstructural properties and electrochemical performance of the graphene fiber electrodes.

Conclusions:

• Graphene fiber-based flexible MEAs represent a significant advancement in neural interface technology.
• These novel neural prostheses offer a viable, high-performance alternative to traditional electrodes.
• The developed fabrication technique enables versatile customization for diverse neuroscience and biomedical research applications.