Non-invasive brain imaging is usually performed with electrodes, sticky gels and wires: it’s an ugly, uncomfortable and time-consuming setup. But scientists have now developed a potential upgrade in the form of temporary electronic tattoos.
These e-tattoos work by using liquid ink that is pressed onto the scalp. A new study has found that they are just as accurate as conventional electroencephalography (EEG) methods, while being much easier to configure. Even better: they can work through the hair (as long as it’s short hair).
According to the researchers who developed the ink, from the University of Texas at Austin and the University of California, Los Angeles (UCLA), this new technique promises advances in patient monitoring and disease diagnosis.
The new approach is faster and more convenient than a traditional EEG. (de Vasconcelos, Cell biomaterials2024)
“Our innovations in sensor design, biocompatible ink and high-speed printing pave the way for future on-body production of electronic tattoo sensors, with broad applications both inside and outside clinical environments,” said electrical engineer Nanshu Lu of the University of Texas. near Austin.
The researchers say their new approach is more comfortable for the subject, lasts longer without any signal degradation, and is more accurate in the data it collects. The e-tattoos are made of conductive polymers and are sprayed directly onto the head using a custom inkjet printer.
These e-tattoos were previously used to measure muscle fatigue and heart rate, but have now been shown to work for brain activity too, with specially designed algorithms that can determine where to place them on the scalp.
Further innovations came in the application of the e-ink to replace some of the wiring in a standard EEG. The researchers were able to use shorter conventional wires to transmit the collected data back to a recording device.
“This adjustment allowed the printed wires to conduct signals without picking up new signals along the way,” says materials scientist Ximin He of UCLA.
As always, there is more work to do. Next, the team behind the e-tattoo wants to develop a way to embed wireless transmission capabilities into the printed e-ink patches, and to make their technology work with a wider range of hairstyles and hair types.
Ultimately, the e-tattoos could also be used as the basis for brain-computer interfaces (BCIs), the researchers say – not just to read brain activity, but to interpret it and use it to trigger actions.
As with EEGs, current setups for BCIs are bulky and difficult to manage. If the current technology could be replaced with something based on e-tattoos, it could potentially become accessible to a much wider group of people.
“Our research has the potential to revolutionize the way non-invasive interface devices between brains and computers are designed,” says neuroengineer José Millán of the University of Texas at Austin.
The research was published in Cell biomaterials.
