Neural sensing of electrical activity with stretchable microelectrode arrays

Area of Science:

• Biomedical Engineering
• Neuroscience
• Materials Science

Background:

• Sensing neural activity in mechanically active tissues is challenging due to electrode stiffness causing tissue damage.
• Traumatic brain injury (TBI) involves rapid, large deformations, exacerbating electrode-related issues.
• Existing rigid electrodes are unsuitable for dynamic tissue environments.

Purpose of the Study:

• To develop and evaluate a stretchable microelectrode array (SMEA) capable of withstanding large deformations.
• To enable stable neural recordings in mechanically active tissues, particularly in TBI models.
• To investigate post-injury neuronal dysfunction in TBI using a novel in vitro model.

Main Methods:

• Fabrication of SMEA using thin metal conductors on polydimethylsiloxane (PDMS) encapsulated with silicone.
• Recording spontaneous and evoked neural activity from brain slice cultures using SMEA.
• Implementing an in vitro TBI model by mechanically stretching SMEA with adherent brain tissue cultures.
• Utilizing image analysis to confirm tissue deformation during mechanical injury.

Main Results:

• The developed SMEA demonstrated resilience to large elastic deformations (>5% biaxial strain) while maintaining functionality.
• SMEA successfully recorded neural activity from brain slice cultures, both spontaneous and evoked.
• Post-injury electrophysiological function was normalized to pre-injury levels due to the SMEA's ability to deform with the tissue.

Conclusions:

• The SMEA is a viable tool for sensing neural activity in mechanically dynamic environments, including TBI models.
• This technology facilitates the study of mechanisms underlying post-traumatic neuronal dysfunction.
• SMEA holds potential for applications in other mechanically active tissues like peripheral nerves and the heart.