Long-Term Implantable, Flexible, and Transparent Neural Interface Based on Ag/Au Core-Shell Nanowires

Area of Science:

• Neuroscience
• Materials Science
• Biomedical Engineering

Background:

• Optogenetics requires advanced neural interfaces for precise control and monitoring of neural circuits.
• Existing interfaces often lack the biocompatibility, transparency, and mechanical properties needed for long-term implantation and chronic studies.

Purpose of the Study:

• To develop a stretchable, transparent, and biocompatible neural interface for optogenetic applications.
• To evaluate the long-term performance and inflammatory response of the novel interface after chronic implantation.

Main Methods:

• Fabrication of conductive tracks using Ag/Au core-shell nanowires for enhanced stretchability and transparency.
• Integration of gel-coated microelectrodes and surface treatment with antithrombogenic polymers.
• Chronic implantation in rodent and nonhuman primate models for performance and biocompatibility assessment.

Main Results:

• The neural interface achieved <60% strain stretchability, <83% transparency, and low electrical resistance (15 Ω sq^-1).
• Low electrode impedance (1.1-3.2 Ω cm²) was maintained in saline over 5 months.
• The interface showed noncytotoxicity, minimal inflammatory response, and enabled clear electrocorticogram recording via optogenetic stimulation.

Conclusions:

• A highly reliable, flexible, and transparent neural interface suitable for optogenetics and chronic implantation was developed.
• The material strategy and surface treatments ensure long-term biocompatibility and signal integrity.
• This interface holds promise for translational research in intractable neurological diseases.