A Bilayer Microfluidics-Based Elastic Encapsulation Method of Liquid Metal Circuits with Cellular Resolution

Area of Science:

• Bioelectronics
• Materials Science
• Microfluidics

Background:

• Microscale mechanical mismatches between bioelectronics and cells impede stable electrophysiological signal recording.
• Liquid metals (EGaIn) offer a low Young's modulus for conformal tissue contact but lack elastic encapsulation for cellular resolution.
• Existing encapsulation methods are limited by polymer properties and high-resolution alignment requirements.

Purpose of the Study:

• To develop a rapid, cost-effective, and scalable method for elastic encapsulation of high-resolution liquid metal electrode arrays.
• To overcome limitations of current packaging techniques for bioelectronic devices.
• To enable stable, high-fidelity electrophysiological signal acquisition at the cellular and in vivo levels.

Main Methods:

• A bilayer microfluidics-based approach was employed for rapid (<3 min) elastic encapsulation of electrode arrays.
• The method is alignment-free, simplifying manufacturing and reducing costs.
• Encapsulated devices were characterized for mechanical properties, flexibility, and biocompatibility.

Main Results:

• The developed method achieved elastic encapsulation of 20 μm electrode arrays with high resolution.
• The resulting bioelectronics demonstrated excellent wear resistance, high flexibility (>300% strain), and biocompatibility.
• High-quality electrophysiological signals were recorded from cardiomyocytes (∼30 dB) and in vivo rat models (∼42 dB).

Conclusions:

• The rapid microfluidics encapsulation technique enhances the precision and integration of liquid metal-based flexible electronics.
• This approach facilitates long-term stable interfacing with biological tissues for high-resolution monitoring.
• The technology holds promise for applications in cellular-level electrophysiological mapping, stimulation, and therapeutic interventions.