As it stands, existing brain implants are eventually rejected by the body. However, one team of researchers have engineered an implant as soft as the tissue surrounding it.
Modern brain implants, as miraculous as they are, aren’t compatible with the human brain. The brain is a vulnerable, delicate organ—as soft as the softest tofu. Yet, brain implants are typically made of metal and other robust, rigid materials that are likely to cause inflammation and the build-up of scar tissue in due time.
MIT engineers are working to develop neural implants that are of soft and flexible materials that can gently conform to the brain’s contours and monitor activity over longer periods without the risk of aggravating the surrounding tissue.
Such flexible electronics would stand as softer alternatives to existing metal-based electrodes designed to monitor brain activity. Further, they may prove especially useful in brain implants that stimulate neural regions to ease the symptoms of epilepsy, Parkinson’s disease, and severe depression.
The research team, led by Xuanhe Zhao, a professor of mechanical engineering and of civil and environmental engineering, has now developed a way to 3D print neural probes and an assortment of other electronic devices as soft and as flexible as rubber.
The team has developed a way to 3D print neural probes and an assortment of other electronic devices as soft and as flexible as rubber.
The devices are made from a type of plastic that is electrically conductive. The polymer solution is normally liquid-like, but the team has been able to transform it into a substance that resembles a viscous toothpaste which they could then feed through a conventional 3D printer to make stable, electrically conductive patterns.
The team printed several soft electronic devices, one of which was a rubbery electrode that was implanted into the brain of a mouse. As the mouse moved freely within the controlled environment, the neural probe was able to pick up on the activity from a single neuron. Monitoring activity such as this can give scientists a higher-resolution picture of the brain’s activity and can help tailor therapies and long-term brain implants for a variety of neurological disorders.
“We hope by demonstrating this proof of concept, people can use this technology to make different devices, quickly,” says Hyunwoo Yuk, a graduate student in Zhao’s group at MIT. “They can change the design, run the printing code, and generate a new design in 30 minutes. Hopefully, this will streamline the development of neural interfaces, fully made of soft materials.”