Sep 03, 2025

Carbon nanotube electrodes promise safer brain interfaces and vision restoration

Researchers created soft, conductive carbon nanotube electrodes that record brain activity safely, opening paths to neural prosthetics and advanced brain-machine interfaces.

(Nanowerk News) Brain–computer interfaces, or BCIs, make it possible to link human thought directly with machines. At the core of this technology are microelectrodes—tiny, hair-thin probes that record or stimulate electrical signals in the brain. But these devices face a long-standing trade-off: stiff metal electrodes record signals reliably but can damage fragile tissue, while softer polymer electrodes are gentler yet often too poor at transmitting signals.

A joint team from Seoul National University of Science and Technology and the Korea Institute of Science and Technology (KIST) has developed a new kind of microelectrode that may solve this problem. Reported in Advanced Functional Materials ("Polymer‐Incorporated Mechanically Compliant Carbon Nanotube Microelectrode Arrays for Multichannel Neural Signal Recording"), the design uses forests of carbon nanotubes (CNTs) embedded in a soft polymer base. The result is a device about 4,000 times softer than silicon, yet still highly conductive—combining the strengths of both metals and polymers.

The team grew vertically aligned CNTs through a multi-step process, then fused them with the elastic base using a proprietary hybridization method. The arrays could be stably inserted into brain tissue, recording precise neural activity with minimal disruption. In tests with mice, the electrodes captured light-driven responses in the visual cortex, while causing less inflammation than conventional tungsten wires.

The electrodes also showed improved long-term safety. One month after implantation, animals with CNT arrays had significantly lower immune responses compared to those with traditional electrodes. This suggests the technology could support more durable brain–machine connections.

Beyond research applications, the system holds promise for medical uses. CNT-based electrodes could be developed for visual prosthetics to restore sight in people with retinal degeneration or optic nerve injuries. They might also support cortical implants that enhance communication, control external devices, or even enable immersive AR and VR interfaces powered by brain signals.

“By merging conductivity with flexibility, we’ve created a stable interface that does not harm surrounding tissue,” said Dr. Jong G. Ok, who co-led the study. The team now aims to shrink the electrode arrays to subcellular scales for even higher-resolution recordings, moving closer to next-generation neural technologies.

Source: Seoul National University (Note: Content may be edited for style and length)