Stretchable Surface Electrode Arrays Using an Alginate/PEDOT:PSS-Based Conductive Hydrogel for Conformal Brain...

Area of Science:

• Biomaterials Science
• Neuroscience
• Materials Engineering

Background:

• Electrocorticography (ECoG) records cerebral cortex activity for brain-interfacing technologies.
• Developing biocompatible, soft, and conductive materials for brain-device interfaces is challenging.
• Optimizing both electrical and mechanical properties of brain-adaptive materials is crucial.

Purpose of the Study:

• To introduce a novel soft tough ionic conductive hydrogel (STICH) for enhanced ECoG monitoring.
• To evaluate the brain-adaptive mechanical properties and electrical performance of STICH.
• To demonstrate the efficacy of STICH-coated electrodes in vivo.

Main Methods:

• Fabrication of stretchable metal electrodes with wavy patterns on an elastomer.
• Coating electrodes with the newly developed STICH hydrogel as an interfacial layer.
• In vivo acute ECoG monitoring in anesthetized rodents using STICH-coated electrodes.

Main Results:

• STICH exhibits brain-adaptive softness (Young's modulus ~9.46 kPa) and high toughness (~36.85 kJ/mm³).
• STICH coating significantly reduced electrode impedance from 60 kΩ to 10 kΩ at 1 kHz.
• STICH-coated electrodes achieved sensitive ECoG recording, showing higher visual-evoked potential (VEP) amplitude than control.

Conclusions:

• The STICH hydrogel provides a robust, conformal interface with the cerebral cortex.
• STICH enhances the electrical performance of ECoG electrodes, improving signal quality.
• This brain-adaptive material shows significant potential for advanced neural monitoring and brain-computer interfaces.