NeuroWorm: China's Brain Implant Electrode Is Thinner Than Hair and Roams the Brain Magnetically

A China-led team of researchers has developed a flexible brain implant electrode array, called NeuroWorm, that is as soft as brain tissue and thinner than a strand of hair. It is the first-ever "dynamic" brain-computer interface electrode, capable of being magnetically steered after implantation, and it demonstrated record-breaking longevity in animal trials.

What Makes NeuroWorm Different?

Traditional brain implants are rigid, fixed in place, and often cause chronic inflammation and signal degradation as stiff electrodes rub against soft brain tissue. NeuroWorm changes this entirely.

The device is a soft, stretchable microfibre about 196 microns in diameter — thinner than a human hair — that houses up to 60 independent electrode channels along its length . It incorporates a tiny magnetic head at one end, enabling external magnetic field control to steer the electrode within the brain in a "roaming" mode. This represents a first-of-its-kind "dynamic electrode" paradigm that breaks from traditional fixed-position implants .

Inspired by the flexible movement and segmented body of an earthworm, the electrode can advance, steer, and change monitoring targets within the brain after implantation — a capability no previous brain implant has demonstrated .

Key Results in Animal Trials

In animal trials, NeuroWorm recorded high-quality neural activity with unprecedented long-term clarity and remained safely functional for 18 months without any drop in performance . This is significantly longer than most existing brain implants, which typically degrade within months due to tissue inflammation or material failure.

NeuroWorm was demonstrated to "roam" inside rabbit skulls, actively changing monitoring targets as needed, and provided stable bioelectrical recordings from both brain and muscle tissue . In muscle tissue, it provided stable bioelectrical monitoring in rats for more than 43 weeks, and even after 54 weeks of implantation, fibroblast encapsulation around the fibre remained negligible .

The Technology Behind the Breakthrough

The electrode is fabricated by rolling a 2D bioelectronic device into a 1D microfibre, creating a self-encapsulated structure with exposed electrode sites as tissue interfaces . The process allows integration of up to 60 discrete channels, and the fibre's softness (using a 400-nm-thick styrene ethylene butylene styrene substrate with patterned gold wires) ensures it matches the mechanical properties of brain tissue — eliminating the source of chronic inflammation .

How It Steers: Magnetic Guidance

The key innovation enabling mobility is the incorporation of a tiny magnetic head at the tip of the electrode. External magnetic fields can then be used to steer the fibre through brain tissue, allowing researchers to target different neural populations without additional surgery . This dynamic capability could enable long-term studies of how neural activity changes over time across different brain regions.

Publication and Research Team

The study was published in Nature on September 17, 2025, by researchers from the Shenzhen Institutes of Advanced Technology (SIAT) under the Chinese Academy of Sciences, the Shenzhen University of Advanced Technology, and Donghua University . The lead researchers include Prof. Liu Zhiyuan, Prof. Xu Tiantian, Assoc. Prof. Han Fei, and Prof. Yan Wei .

Why This Matters for Brain-Computer Interfaces

NeuroWorm addresses two of the biggest challenges holding back brain-computer interfaces: the short functional lifespan of implanted electrodes and the inability to record from multiple brain targets without inserting multiple rigid probes . By enabling a single implant to dynamically move and record for over a year, it opens new possibilities for studying long-term neural dynamics and for future BCI applications in treating neurological conditions.