Conformable neural interface based on off-stoichiometry thiol-ene-epoxy thermosets.

Area of Science:

• Biomaterials Science
• Neuroscience Engineering
• Polymer Science

Background:

• Off-stoichiometry thiol-ene-epoxy (OSTE+) thermosets exhibit desirable properties like low permeability, minimal molecular absorption, and low Young's modulus.
• These characteristics make OSTE+ suitable for microfluidic chip prototyping and show potential for neural implants due to mechanical properties and cleanroom compatibility.

Purpose of the Study:

• To investigate the suitability of OSTE+ as a material for implantable neural interfaces.
• To develop and evaluate a conformable micro-electrocorticography (ECoG) array using OSTE+ for neural recording and stimulation.

Main Methods:

• Fabrication of a multilayer micro-ECoG array with 16 platinum electrodes coated with platinum black using OSTE+.
• Evaluation of the array's mechanical conformability to curved surfaces.
• Assessment of device stability, biocompatibility, and performance in acute and chronic implantation studies in mice.

Main Results:

• The OSTE+ micro-ECoG array demonstrated conformability to the mouse cortex, enabling multimodal recording and stimulation of neural tissue.
• The material exhibited low permeability and strong layer adhesion, contributing to device stability.
• Implantation studies showed no cytotoxicity and only a modest foreign body response after chronic implantation.

Conclusions:

• OSTE+ is a promising material for developing conformable and stable implantable neural interfaces.
• The fabricated OSTE+ micro-ECoG array successfully recorded and stimulated neural tissue in vivo.
• The material's biocompatibility and mechanical properties support its application in neural implants.