The fibres created by Matteo at Rice University have proven superior to metal electrodes for deep brain stimulation and to read signals from a neuronal network. Because they provide a two-way connection, they show promise for treating patients with neurological disorders while monitoring the real-time response of neural circuits in areas that control movement, mood and bodily functions.
New experiments show that the biocompatible fibres are ideal candidates for small, safe electrodes that interact with the brain’s neuronal system, and could replace much larger electrodes currently used in devices for deep brain stimulation therapies in Parkinson’s disease patients.
They could also advance technologies to restore sensory or motor functions and brain-machine interfaces as well as deep brain stimulation therapies for other neurological disorders, including dystonia and depression, the researchers wrote.
The fibres are made from bundles of long nanotubes originally intended for aerospace applications where strength, weight and conductivity are paramount. The individual nanotubes measure only a few nanometers across, but when millions are bundled in a process called wet spinning, they become thread-like fibres about a quarter the width of a human hair.
Matteo Pasquali said on the creation of the fibres;
We developed these fibres as high-strength, high-conductivity materials. Yet, once we had them in our hand, we realised that they had an unexpected property: They are really soft, much like a thread of silk. Their unique combination of strength, conductivity and softness makes them ideal for interfacing with the electrical function of the human body.
Intensive testing on cells and then in rats with Parkinson’s symptoms proved the fibres are stable and as efficient as commercial platinum electrodes at only a fraction of the size. The soft fibres caused little inflammation, which helped maintain strong electrical connections to neurons by preventing the body’s defences from scarring and encapsulating the site of the injury.
Doctors who implant deep brain stimulation devices start with a recording probe able to “listen” to neurons that emit characteristic signals depending on their functions, once a surgeon finds the right spot, the probe is removed and the stimulating electrode gently inserted. Rice carbon nanotube fibres that send and receive signals would simplify implantation.
The fibres could one day lead to self-regulating therapeutic devices for Parkinson’s and other patients. Current devices include an implant that sends electrical signals to the brain to calm the tremors that afflict Parkinson’s patients.