Engineers invent advanced brain-computer interface with microneedles

Engineering researchers at the University of California, San Diego have invented an advanced brain-computer interface (BCI) comprised of a flexible, moldable scaffold and penetrating micro-needles. The flexible backing allows the BCI to conform more evenly to the complex curved surface of the brain. It also allows the BCI to more evenly distribute the microneedles that pierce the cortex.

Micro-needles and flexible support

These micro needles are 10 times thinner than human hair and come out of the flexible backing. They then penetrate the surface of the brain tissue without piercing the surface venules. Microneedles are able to record signals from nerve cells in the cortex.

The new system has been tested in rodents and the research has been published in the journal Advanced functional materials.

The team was led by electrical engineering professor Shadi Dayeh at the university. It was also made up of Boston University researchers led by biomedical engineering professor Anna Devor.

The system has demonstrated performance on par with the existing gold standard for BCIs with penetrating needles. Called the Utah Array, this standard has been shown to help people with spinal cord injuries and stroke victims. They can use their thoughts to control robotic limbs and other devices.

The flexibility and conformability of the new BCI allows for closer contact between the brain and the electrodes, allowing better and more consistent recording of brain activity signals. The way the BCI is constructed allows for larger sensing surfaces, which helps it to simultaneously monitor a larger surface area of ​​the brain.

In the experiments, the penetrating microneedle array consisting of 1,024 microneedles was able to successfully record signals triggered by specific stimuli from the brains of rats. This means that it covers ten times the surface of the brain compared to current technologies.

Soft-backed BCIs are also thinner and lighter than traditional ones, which use glass backings. The new type of supports could reduce the irritation of the brian tissue that comes into contact with the sensor array.

The flexible supports are also transparent, which the researchers say could be exploited to perform basic neuroscience research involving animal models that would otherwise be impossible.

Robotic hands with tactile feedback

The researchers say that penetrating microneedle arrays with wide spatial coverage will be needed to improve BCIs in the future and allow them to be used in ‘closed-loop systems’. This could help people with severely reduced mobility and could provide tactile feedback for someone using a robotic hand.

The robotic hand’s touch sensors could detect an object’s texture, hardness, and weight. They would record information that could be translated into electrical stimulation patterns that travel through wires outside the body to the BCI. The brain would receive information directly from these electrical signals about the object, and the person could then adjust their grip based on the detected information.

The Dayeh laboratory has already invented various tactical sensors that could be used for these applications.