High-Performance Magnetically Actuated MXene-Based Microelectrodes for Epineural Interfacing

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Spinal cord interfaces are crucial for restoring motor function after spinal cord injury (SCI).
• Current spinal cord interface designs face challenges balancing invasiveness and interfacial impedance.
• Minimally invasive approaches are needed to improve therapeutic outcomes for SCI.

Purpose of the Study:

• To develop a magnetically actuated robotic spinal cord probe (RSCP) to overcome the invasiveness-impedance trade-off.
• To create a novel composite material (MxP) for enhanced electrode performance and biocompatibility.
• To evaluate the in vivo performance and biocompatibility of the RSCP for potential SCI treatment.

Main Methods:

• Fabrication of a composite material (MxP) from MXene and PEDOT:PSS integrated with a magnetic elastomer (ME) substrate.
• Magnetic actuation of the RSCP for controlled positioning and conformity to spinal cord anatomy.
• Impedance measurements, electrochemical stability tests, and in vivo biocompatibility assessment (immunohistochemistry) in mice.

Main Results:

• Magnetic actuation achieved >5 mm deflection, enabling spinal cord contouring.
• Magnetic positioning significantly reduced interfacial impedance by up to 27% (5-5000 Hz).
• MxP electrodes exhibited superior electrochemical stability over 21 days, with minimal in vivo gliosis and microglial activation.

Conclusions:

• Magnetically actuated RSCPs offer a promising solution to the invasiveness-impedance trade-off in spinal cord interfaces.
• The developed MxP material demonstrates enhanced stability and biocompatibility.
• This technology provides a foundation for improved therapeutic strategies for spinal cord injury recovery.