0
0
In a groundbreaking development, scientists have created a liquid ink that can be directly printed onto the scalp to measure brain activity, offering a more comfortable, hair-friendly alternative to traditional methods of monitoring brainwaves. This innovative technology, published on December 2 in Cell Biomaterials, could revolutionize how neurological conditions are diagnosed and monitored, as well as enhance brain-computer interface applications.
Electroencephalography (EEG), a standard method for diagnosing conditions like epilepsy, brain tumors, and brain injuries, traditionally requires technicians to measure and mark the scalp before gluing electrodes to it. This process is both time-consuming and uncomfortable, often involving long wires attached to bulky equipment. However, the new technology, developed by researchers at the University of Texas at Austin, aims to simplify this procedure using a temporary “electronic tattoo” directly printed onto the scalp.
Nanshu Lu, co-corresponding author of the study and a professor at the University of Texas at Austin, explains, “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.”
The research team has been advancing the field of electronic tattoos, or “e-tattoos,” which are small sensors designed to track bodily signals from the skin. While e-tattoos have previously been used to monitor heart activity and muscle fatigue, challenges arose when trying to adapt the technology to the scalp, which is covered in hair. Traditional e-tattoos, printed on adhesive layers, were ineffective on hair-covered areas. To overcome this, the team developed a novel liquid ink made from conductive polymers that flows through hair follicles to create thin-film sensors capable of detecting brain activity.
The new ink is applied using a digitally controlled inkjet printer, which quickly and non-invasively deposits the e-tattoo ink onto the patient’s scalp. The process requires no physical contact, making it a pain-free experience for the patient. The researchers tested the e-tattoo electrodes on five participants with short hair, comparing them to traditional EEG electrodes. The results were promising, with the e-tattoos performing comparably to conventional electrodes in detecting brainwaves while minimizing signal noise.
The research team also discovered that e-tattoos outperformed traditional EEG electrodes over time. After six hours, the gel in conventional electrodes began to dry out, causing over a third of the electrodes to fail, while the e-tattoo electrodes maintained stable connectivity for at least 24 hours. Furthermore, the researchers adapted the ink formula to print conductive lines that replaced the standard EEG wires, allowing signals to be transmitted without interference.
Looking ahead, the team envisions a future where the e-tattoo electrodes could be integrated with wireless transmitters, enabling a fully wireless EEG process. This development could significantly reduce the complexity and discomfort of traditional EEG tests, providing a more convenient and efficient solution for both clinicians and patients.
The new e-tattoo technology could also have significant implications for brain-computer interface (BCI) devices. These systems allow users to control external devices through brain activity, without the need for physical movement. Currently, BCIs rely on bulky headsets or external equipment, but e-tattoos could simplify the technology by integrating sensors directly onto the scalp, making BCIs more accessible and comfortable.
José Millán, another co-corresponding author of the study, emphasizes the broader potential of the technology, saying, “Our study can potentially revolutionize the way non-invasive brain-computer interface devices are designed.” As research continues, the e-tattoo technology could pave the way for more advanced, user-friendly methods of monitoring brain activity and enhancing brain-computer communication.
