3D-printed brain sensors could unlock personalised neural monitoring

3D brain sensors tailored to each person could improve monitoring and treatment of neurodegenerative disease, researchers say.

Traditional brain sensors, known as bioelectrodes, are tiny devices that track signals in the brain.

They are usually made from stiff materials in a one-size-fits-all design that struggles to match the brain’s complex structure.

Researchers have developed a 3D-printing approach for soft, stretchy electrodes that can fit the small differences that make every brain unique.

The research used MRI scans from 21 patients to simulate detailed models of their brains.

The team then shaped electrodes to fit each brain’s specific contours before 3D-printing the electrodes and brain models.

Tao Zhou, assistant professor of engineering science and mechanics at Penn State and corresponding author on the study, said: “Each person has a different brain structure, depending on their height, weight, age, sex and more.

“Despite this, we try to fit neural interfaces onto brains like they have identical structures.

“This motivated us to create electrodes that are tailored for each individual, based on the structure of their brain.”

The electrodes are made mainly from hydrogel, a soft, water-rich material designed to work with delicate brain tissue.

The team also used a honeycomb-inspired structure which Zhou said offers flexibility and strength while remaining cost-effective and quick to print.

Zhou said: “The honeycomb structure helps us significantly reduce the stiffness of the electrodes, without sacrificing their mechanical strength.

“What’s more, the structure helps us reduce the overall material used during fabrication, reducing production time, cost and environmental impact.”

The researchers said their electrodes fit the brain’s structure better than traditional designs while remaining effective and biologically compatible, including in rat tests.

They also said the hydrogel sensors can be applied to soft brain tissue without causing damage and do not disrupt fluid transport around the brain, which is a critical part of normal brain function.

“Personalising the electrodes to the brain’s specific structure substantially improves their reliability,” Zhou said.

“Because they conform to the brain better, the signal quality itself is significantly improved.”

In animal testing, the electrodes were placed on the brains of rats for 28 days.

The researchers reported no immune response and no decline in performance over that period, while also recording sensitive and accurate electrical and physiological signals.

Zhou said the printing method could potentially serve as a framework for producing customised bioelectrodes at commercial scale for specific patients.

The team plans to explore how personalised electrodes might contribute to neurological treatments beyond monitoring.

He said: “We are looking to further improve this technology to optimize the electrodes to monitor for specific diseases.

“In the future, we would really like to work with patients to see how this approach could support brain monitoring and disease treatment in clinical settings.”