Shooting up with a syringe full of electronics is no longer an off-brand cyberpunk fantasy — in fact, it could be a valuable scientific procedure. In this week's issue of Nature Nanotechnology, a Harvard research group is showing off a thin mesh that could track brain activity with less invasive implantation methods. It might not be a cranial surgical implant so much as a cranial injection.
Flexible tech can stick straight to human or animal organs, allowing for close-up monitoring. Stretchy "electronic tattoos," for example, could keep tabs on heart or breathing rhythms. But once scientists move beyond skin, these devices will need to be surgically implanted, which can raise difficulties. The Harvard team addressed this problem in a novel way. The mesh they created — made of thin polymer and metal threads — does the job of traditional electrodes, but it integrates into the brain, acting like a scaffold that cells can bind to. This structure creates a solid connection for tracking or stimulating individual neurons, but that's not the only advantage. It can also roll up to incredibly small widths, making it thin enough to be loaded into a 100-micrometer glass needle. And once it's injected into a region of the brain, it can relax and unfurl, blanketing the area around it.
In their experiment, the researchers tested this on synthetic gel, demonstrating that it could actually unroll and settle into a brain-like structure. Then, they moved on to something more direct: injecting the mesh into real, live mice. In order to do so, they still needed to remove part of the skulls, but the researchers say it's a smaller area than purely surgical implants would require. Five weeks after the injection, the mesh had spread out, and imaging showed healthy neurons around it. It also served its purpose: the researchers could map brain activity by connecting to a set of tiny protruding wires.
According to the accompanying Nature news article, the team hopes to move on to larger meshes with different types of sensors, and it wants to inject the mesh into newborn mice to see how it unwrapped as they grew. The paper also mentions a wireless interface. If human tests ever come, they'll be far in the future. But overall, it's research that can help us better understand the brain, and its applications could grow as we learn more.