China's 'floating' 3D origami brain implant could prevent thread retraction seen in Neuralink
Chinese researchers have developed a groundbreaking soft and stretchable origami-inspired brain implant. This innovative design moves with the brain, rather than remaining rigid, and has the potential to revolutionize brain-computer interface (BCI) technology.
The new implant utilizes a technique called kirigami, which involves strategic cuts and folds to create intricate 3D structures. By starting with a flat sheet and adding precise cuts, the material can transform into a 3D shape when stretched or folded, allowing flat materials to stretch, flex, and twist without breaking.
Currently, BCIs, such as those developed by Neuralink, use tiny electrode threads inserted into the brain to record neural signals. However, these threads tend to be rigid, which is problematic because the brain constantly moves due to heartbeat and breathing. This rigidity often leads to thread retraction, a significant issue that reduces signal quality and can cause inflammation or tissue damage.
The researchers emphasized the need for implantable microelectrode arrays that can interface with numerous neurons across large spatial and temporal scales. This is where origami-inspired brain implants come into play.
In 2024, Neuralink's first human implant reportedly lost significant functionality due to thread retraction, where many threads moved out of position. This is a critical weakness for BCIs. Fang Ying, a senior researcher at the Chinese Institute for Brain Research, Beijing, highlighted the risk of retraction caused by brain movement, prompting the exploration of new approaches.
To address this challenge, the Chinese Academy of Sciences team transformed the ancient Japanese paper-folding technique into coil-like (spiral) BCI electrode threads, rather than straight ones. Spirals offer the advantage of stretching and compressing while absorbing motion, reducing mechanical stress on brain tissue.
The new BCI is placed on a layer of hydrogel, further reducing friction, minimizing tissue damage during insertion, and acting as a buffer from brain movement. This design enables the electrodes to 'float' on the brain, avoiding the rigidity of traditional implants.
When tested on macaque monkeys, the origami-BCI demonstrated remarkable performance, recording activity from over 700 cortical neurons simultaneously. It covered a large area of the brain, maintained stable recordings, and exhibited low displacement compared to conventional designs.
This breakthrough is significant because BCIs have diverse applications, including assisting paralyzed patients with controlling robotic limbs, restoring speech, treating neurological disorders, and potentially enhancing human cognition. Ensuring the interface between the brain and technology can move without causing damage is crucial for long-term viability.
If this kirigami-inspired approach can overcome thread retraction, it will be a significant advancement for BCI technology. The study, published in Nature Electronics, provides further insights into this innovative technology.
