Stretchable Tissue-Like Gold Nanowire Composites with Long-Term Stability for Neural Interfaces

Area of Science:

• Biomaterials Science
• Neuroscience Engineering
• Nanotechnology

Background:

• Soft and stretchable nanocomposites are crucial for neural interfaces to mimic neural tissue properties.
• Existing materials often fail to combine low Young's modulus, high conductivity, stretchability, and biocompatibility.
• Current nanocomposites lack the necessary combination of softness and high conductivity for effective neural interfacing.

Purpose of the Study:

• To develop a scalable synthesis route for soft, conductive nanocomposites for neural interfaces.
• To address the limitations of current materials in achieving both softness and high conductivity.
• To create advanced neural interface materials with improved biocompatibility and chronic stability.

Main Methods:

• Developed a scalable synthesis route using polymeric reducing agents for gold nanowires (AuNWs).
• Fabricated AuNW-silicone composites with controllable AuNW dimensions and excellent biocompatibility.
• Engineered soft multielectrode cuffs using the developed nanocomposite material.

Main Results:

• Achieved nerve-like softness (250 kPa), high conductivity (16,000 S cm⁻¹), and reversible stretchability in AuNW-silicone composites.
• Demonstrated selective functional stimulation and recording of sensory stimuli in rat sciatic nerves using the multielectrode cuffs.
• Showcased accelerated lifetime stability exceeding 3 years for the neural interface devices.

Conclusions:

• The developed scalable synthesis method provides a chemically stable alternative to silver nanowires (AgNWs).
• The AuNW-silicone nanocomposites meet critical requirements for advanced neural interfaces.
• Enabled new applications in electronics, biomedical devices, and electrochemistry due to material properties and stability.