The findings, led by Fang Ying, a senior researcher at the Chinese Institute for Brain Research Beijing, were published on Thursday in Nature Electronics, describing a flexible electrode that combines high-throughput neural signal collection with improved biomechanical compatibility.

Researchers said the new design allows implanted electrodes to mechanically conform to natural brain pulsation and intracranial displacement, which may reduce signal loss and tissue damage while improving long-term BCI stability.

Regarding the research background, Fang said the work was motivated by earlier invasive BCI experiments in non-human primates.

"About four years ago, we found that flexible electrodes carried a real risk of retraction due to brain movement," Fang said.

"That prompted us to explore new approaches to reduce the risk of electrodes being pulled out when one end is anchored to the brain and the other is fixed to the skull."

In a related development, the issue drew wider attention in 2024 after Elon Musk’s Neuralink conducted its first human invasive BCI clinical trial.

About 85% of the 1,024-channel flexible electrodes implanted in that patient retracted from the brain within weeks, largely because they were bendable but not stretchable and could not accommodate natural brain motion.

Traditional linear electrodes face difficulty adapting to continuous brain pulsation and intracranial movement, making them prone to displacement or detachment from neural tissue.

Such detachment can reduce both the quantity and accuracy of neural signals collected and may also trigger inflammatory responses in brain tissue.

As a result, Fang’s team said developing flexible electrodes capable of adapting to brain dynamics and enabling stable long-term signal recording remains a major barrier to clinical BCI application.

To address this challenge, the researchers proposed a high-throughput stretchable electrode architecture.

According to the study, the design uses ultrathin flexible films with very low bending stiffness to redirect tensile stress into low-energy buckling deformation, enabling electrodes to track brain pulsations after implantation and maintain stability in neural tissue.

Explaining the technical approach, Fang said the key innovation is a spiral structural design.

"We designed the electrode as a coiled structure. Because it is ultrathin, it bends very easily," Fang said.

"Through structural design, we convert stretching into bending and twisting of the electrode itself, which dramatically reduces the force required for stretching. After implantation, the electrode can move up and down with the brain's natural pulsation, preventing displacement or retraction like what we saw with Neuralink's electrodes."

In terms of mechanical properties, Fang said the stretchable electrodes are significantly softer than conventional linear designs.

She said stretching Neuralink’s linear electrodes by 100 micrometers requires about 4 millinewtons of force, while the new stretchable electrodes require roughly 37 micronewtons, about one-hundredth as much.

This lower force may reduce mechanical stress on brain tissue and help avoid immune reactions and glial scarring often associated with traditional electrodes.

To validate performance, the team conducted implantation tests in monkeys.

The experiments showed the stretchable electrodes enabled long-term stable neural recordings in primate brains.

Additionally, researchers implanted a 1,024-channel high-density stretchable electrode array in a primate brain, matching the scale of Neuralink’s core specifications.

According to the research document, the system achieved large-scale, high-quality neuronal signal recordings, supporting the performance advantages of the stretchable design.

More broadly, BCI technology enables direct information exchange between the brain and external devices and is widely viewed as a pathway toward closer integration between human intelligence and artificial intelligence.

Major countries and regions are accelerating BCI research, and China has included BCI development in recommendations for its upcoming 15th Five-Year Plan, signaling national-level support for the field.