• Posted December 3, 2024

Temporary Scalp Tattoo Can Track Your Brainwaves

Folks soon might have their brain activity scanned using a temporary tattoo, a new study suggests.

This temporary scalp tattoo allowed researchers to track electrical brain activity much more easily than with conventional electrodes, researchers reported Dec. 2 in the journal Cell Biomaterials.

Electronic tattoos, or e-tattoos, printed onto the scalps of five people performed just as well as electrodes at detecting brainwaves, researchers report.

The e-tattoos also were easier to apply and lasted longer than an electrode array glued to the scalp, researchers found.

“Our innovations in sensor design, biocompatible ink and high-speed printing pave the way for future on-body manufacturing of electronic tattoo sensors, with broad applications both within and beyond clinical settings,” said researcher Nanshu Lu, a professor of biomedical engineering with the University of Texas at Austin.

Doctors use electroencephalography (EEG) to diagnose, track and treat a wide variety of illnesses, including seizures, cancer, epilepsy and brain injury.

A traditional EEG test requires technicians to measure each patient’s scalp with rulers and pencils, marking more than a dozen spots where electrodes could be glued and wired, researchers said in background notes.

It’s a time-consuming process, so Lu and her team decided to see whether such electrode arrays could be replaced with liquid ink e-tattoos. These tattoos contain sensors that can track electrical activity in the body.

The team designed a liquid ink made of conductive polymers. The ink can flow through hair to reach the scalp and, once dried, pick up brain activity through the scalp.

Using a computer, researchers design the tattoo’s pattern to best track brain activity, then apply it using a digitally controlled inkjet printer. The process is quick, requires no contact and causes no discomfort, researchers said.

The e-tattoo also maintained stable connectivity for at least 24 hours, while traditional electrodes start to dry out after about six hours, researchers said. More than a third of the electrodes failed to pick up any signal at all after they’d dried out, and most of the rest had less accurate signal detection.

Researchers also improved on the e-tattoo design by running lines down to the base of the participants’ heads, replacing the wires used in a standard EEG test.

“This tweak allowed the printed wires to conduct signals without picking up new signals along the way,” explained researcher Ximin He, an associate professor of materials science and engineering with the University of California, Los Angeles.

In the future, researchers plan to embed wireless data transmitters so that the e-tattoos can track brain waves without any wires at all.

This sort of e-tattoo also could be used with devices that help disabled people speak through computers or operate wheelchairs or robotic limbs, the researchers added. Currently, these sorts of devices require a large, cumbersome headset or invasive brain implants to operate.

“Our study can potentially revolutionize the way noninvasive brain-computer interface devices are designed,” researcher José Millán, chair of neuroengineering with the University of Texas at Austin, said in a journal news release.

More information

The University of Texas at Austin has more on e-tattoos.

SOURCE: Cell Press, news release, Dec. 2, 2024