Soft Gold Wires Connect Nerves and Electronics

Against connection issues like Neuralink: Soft nanowires made of gold can help to securely connect electronics to the gelatinous human nervous system. Neuroimplants and brain stimulators are intended to alleviate diseases such as epilepsy, Parkinson's, paralysis or chronic pain more reliably.

When the connection fails: Neuralink, Elon Musk's medical technology company, was confronted with unexpected problems with its first patient and their brain computer interface (BCI): The implant's tiny wires pulled out of position, affecting data transmission and limiting the BCI system's performance.

While Neuralink is now sending more data over remaining wires, the difficulties highlight the complex integration of electronics into the delicate, soft tissue of the human brain. Novel gold nanowires developed in Sweden aim to make BCI interfaces more reliable and secure.

Innovative Material Science and Production

While traditional conductors in electronics are hard and rigid, researchers at Linköping University, led by Professor Klas Tybrandt, have embedded their connecting leads in an elastic material. The soft microelectrodes thus combine high electrical conductivity with biocompatibility and are gentler on tissue than conventional hard electrodes.

Silicone rubber, a material often used in medical implants, forms the basis of these electrodes, which also contain gold and platinum - metals commonly used in clinical devices. Producing long, narrow gold structures has been problematic until now, but Laura Seufert, a PhD student in Tybrandt's research group, developed a method in which gold is "grown" on a silver nanowire template. After removing the silver, a material consisting of over 99 percent gold remains. This technique avoids the difficulties associated with the direct production of gold nanowires.

Long-term Stability and Application

In clinical tests, the researchers were able to show that these soft and elastic microelectrodes are able to stimulate nerves in rats and record signals from them. The longevity of the material has been tested for at least three years, making it suitable for long-term applications in the body, and the researchers are currently working on further refining the material and developing smaller electrodes that can get even closer to nerve cells. The new interconnect material is expected to mark a milestone in the development of brain interfaces and other neurostimulators, significantly advancing the way electronic devices interact with the human body. (uh)