The brain is one of the most vulnerable organs, as soft as tofu. Brain implants, alternatively, are typically created from metal and other inflexible materials that, over time, can cause the development of scar tissue.
MIT researchers are working on creating soft, flexible neural implants that can gently conform to the brain’s contours and monitor activity over longer periods, without aggravating surrounding tissue. Such flexible electronics could be softer options to existing metal-based electrodes meant to monitor brain exercise. They may also be helpful in brain implants that stimulate neural areas to ease symptoms of epilepsy, Parkinson’s illness, and severe despair.
Guided by Xuanhe Zhao, a professor of mechanical engineering and of civil and environmental engineering, the analysis team has now found a way to 3D print neural probes and other digital devices that are as soft and flexible as rubber.
The units are produced from a type of polymer, or soft plastic, that’s electrically conductive. The team remodeled this normally liquid-like conducting polymer solution into a substance like viscous toothpaste—which they could then feed through a traditional 3D printer to make steady, electrically conductive patterns.
The staff printed several soft digital gadgets, along with a small, rubbery electrode, which they implanted in the brain of a mouse. As the mouse walked freely in a controlled atmosphere, the neural probe was able to pick up on the activity from a single neuron.
Monitoring this activity can give scientists a higher-resolution image of the brain’s activity, and might help in tailoring therapies and long-term brain implants for a wide range of neurological disorders.