The future of diagnostic medicine is gearing up to look a bit more cyberpunk. Scientists have just unveiled technology that should allow people to one day have their brains and bodies monitored via customized, temporary electronic tattoos.
Scientists at the University of Texas at Austin and others developed the tech, which aims to avoid the limitations of conventional electroencephalography, or EEG, testing. The researchers were able to successfully measure people’s brain activity using specially designed liquid ink that was non-invasively printed onto their patients’ scalps. The innovation might make EEGs and other diagnostic tests much more convenient to perform.
EEGs are a crucial tool for monitoring people’s brain health and diagnosing various conditions like epilepsy, sleep apnea, or brain tumors. But it’s a cumbersome procedure, since medical personnel need to carefully mark and maneuver the placement of electrodes on a person’s scalp, which can take up to two hours. EEG caps and other developments have made the process easier over time, but they have their drawbacks too. The caps still require bundles of wires attached to it that can be uncomfortable for patients to wear, for instance, and the wet gel often used to improve the electrodes’ signal dries off within hours.
The UT researchers believe their tech can sidestep many of these disadvantages. They’re not the first scientists to create ultrathin sensors that can track biometrics from the surface of our skin, which are commonly referred to as electronic tattoos (also called e-tattoos). But past versions have needed to be placed on hairless skin, limiting their utility. To overcome this hurdle, the researchers developed specialized liquid ink made of conductive polymers that can still measure brain activity through a person’s hairy scalp once dried.
The team tested out their ink on five volunteers with short hair. They used a computer algorithm to pinpoint the best places to apply the ink electrodes, which were then quickly applied to the person’s scalp via a digitally controlled inkjet printer. Traditional electrodes were also attached to the volunteers’ head for comparison. Compared to the typical electrodes, the e-tattoos appeared to perform about as well at measuring the volunteers’ brain activity, the researchers found. The e-tattoos also lasted longer, with a stable connection lasting up to 24 hours, while the usual electrodes began to lose their signal by the six hour mark as the gel dried out.
In another round of experiments, the researchers modified the ink to additionally produce lines that can replace the wiring used in a conventional EEG. This version not only allowed the researchers to use less physical wires, but also appeared to reduce the risk of signal interference.
“This study introduces a breakthrough in noninvasive brain-monitoring technology through on-scalp-printed and self-drying conductive inks for electroencephalography (EEG),” the researchers write in their paper detailing their experiments, published Monday in Cell Biomaterials.
It will take more research to validate the accuracy of the team’s technology compared to traditional methods. But if their work pays off, it could lead to a range of applications. In addition to improving the EEG, the researchers believe their ink-based sensors can be game changers for brain-computer interface devices as well. These devices record and translate brain activity to perform external commands, such as moving a robotic limb through thought alone. The ink could make it so people would no longer need to wear clunky headsets to operate these devices, the researchers say.
“Our study can potentially revolutionize the way non-invasive brain-computer interface devices are designed,” said researcher José Millán, a biomedical engineer at UT Austin who specializes in these devices, in a statement from the university.
The researchers still have many small and large adjustments to make to their technology before it’s ready for public use. They eventually hope to lace their ink with wireless data transmitters, for instance, which could allow doctors to someday perform a truly wireless EEG test.