Nanoenabled Direct Contact Interfacing of Syringe-Injectable Mesh Electronics.

Area of Science:

• Neuroscience
• Materials Science
• Biomedical Engineering

Background:

• Flexible polymer-based electronics, like injectable mesh electronics, offer promise for chronic neural circuit studies in vivo.
• A key challenge is creating stable, high-yield, low-resistance input/output (I/O) connections for these flexible devices.

Purpose of the Study:

• To develop a novel interfacing paradigm for injectable mesh electronics that ensures high-yield, stable, and low-resistance electrical connections.
• To address the limitations of current I/O connection methods for flexible neural probes.

Main Methods:

• Fabrication of nanoscale-thickness, two-sided metal I/O pads designed for orientation-independent contact.
• Systematic studies on contact resistance, I/O pad design, and mechanical properties, including bending stiffness.
• Computational modeling to establish design rules for high-yield multiplexed interfacing with angular misalignment.
• In vitro and in vivo testing of 32-channel mesh electronics probes with the developed direct contact interface.

Main Results:

• Demonstrated facile fabrication of two-sided metal I/O pads enabling reliable contact.
• Identified bending stiffness as crucial for achieving low-resistance, stable electrical contacts.
• Computational studies provided guidelines for misalignment tolerance in multiplexed connections.
• Achieved high yield of electrical connectivity in vitro and demonstrated chronic stability in vivo over 2 months for neural recording.

Conclusions:

• The developed direct contact interfacing methodology provides a scalable solution for long-term neural recording and modulation using mesh electronics.
• This approach facilitates reliable interconnection of flexible electronics for biological studies and therapeutic applications.