Liquid crystal elastomers as substrates for 3D, robust, implantable electronics.

Area of Science:

• Biomaterials Engineering
• Neurotechnology
• Soft Robotics

Background:

• Designing implantable devices requires materials compatible with soft biological tissues.
• Long-term in vivo use necessitates resistance to harsh mechanical and chemical conditions.
• Existing materials often lack the necessary durability and flexibility for advanced neural interfaces.

Purpose of the Study:

• To design and fabricate mechanically and chemically robust 3D implantable electronics.
• To utilize shape-programmable liquid crystal elastomers (LCEs) for advanced device architectures.
• To create extrinsically stretchable electronics from intrinsically low failure strain materials.

Main Methods:

• Photolithography was used to pattern electronics onto liquid crystal elastomers (LCEs).
• Chemical durability was assessed using accelerated in vitro conditions simulating physiological environments.
• Twisted nematic LCEs were employed as dynamic substrates to achieve programmed 3D shapes.

Main Results:

• LCE materials demonstrated excellent chemical durability, with less than 1% mass change in hydrolytic media simulating over a year in vivo.
• Electronics fabricated on planar LCE substrates successfully morphed into programmed 3D shapes upon release.
• Helical multichannel electrode arrays withstood over 10,000 cycles of 60% strain stretching and buckling in phosphate-buffered saline.

Conclusions:

• Liquid crystal elastomers offer a promising platform for creating mechanically robust and chemically stable 3D implantable electronics.
• The developed LCE-based electronics exhibit enhanced stretchability and durability, suitable for dynamic biological environments.
• These advancements pave the way for next-generation implantable neural interfaces and biosensors.