By Stephen Beech via SWNS<\/a><\/strong><\/p>\n A temporary head tattoo printed directly on the scalp has provided a “hair-friendly” solution for measuring brainwaves.<\/p>\n A liquid ink that doctors can print onto a patient\u2019s scalp to measure brain activity has been invented by American scientists.<\/p>\n They say the new technology offers a “promising” alternative to the cumbersome process currently used for monitoring brainwaves<\/a> and diagnosing neurological conditions.<\/p>\n It also has the potential to enhance non-invasive brain-computer interface applications, according to a study published in the journal Cell Biomaterials<\/a>.<\/p>\n Co-corresponding author Professor Nanshu Lu said: \u201cOur 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.\u201d<\/p>\n She explained that electroencephalography (EEG) is an important tool for diagnosing neurological conditions – including seizures, brain tumors, epilepsy, and brain injuries.<\/p>\n During a traditional EEG test, technicians measure the patient\u2019s scalp with rulers and pencils, marking over a dozen spots where they will glue on electrodes, which are connected to a data-collection machine via wires to monitor the patient\u2019s brain activity.<\/p>\n However, the set-up is time-consuming and can be uncomfortable for many patients, who must sit through the EEG test for hours.<\/p>\n = Lu and her team at the University of Texas, Austin<\/a>, have been pioneering the development of tiny sensors that track bodily signals from the surface of human skin- a technology known as electronic tattoos, or e-tattoos.<\/p>\n Scientists have applied e-tattoos to the chest to measure heart activities, on muscles to measure how fatigued they are, and even under the armpit to measure components of sweat.<\/p>\n Previously, e-tattoos were usually printed on a thin layer of adhesive material before being transferred onto the skin.<\/p>\n EEG setup with e-tattoo electrodes. (Nanshu Lu via SWNS)<\/p>\n But that method was only effective on hairless areas.<\/p>\n Lu said: \u201cDesigning materials that are compatible with hairy skin has been a persistent challenge in e-tattoo technology.”<\/p>\n To overcome the issue, the Texas team designed a type of liquid ink made of conductive polymers.<\/p>\n The ink can flow through the hair to reach the scalp, and once dried, it works as a thin-film sensor, picking up brain activity through the scalp.<\/p>\n Using a computer algorithm, Lu says researchers can design the spots for EEG electrodes on the patient\u2019s scalp.<\/p>\n Then, they use a digitally controlled inkjet printer to spray a thin layer of the e-tattoo ink onto the spots.<\/p>\n Lu says the process is quick, requires no contact, and causes no discomfort in patients.<\/p>\n The team printed e-tattoo electrodes onto the scalps of five participants with short hair.<\/p>\n They also attached conventional EEG electrodes next to the e-tattoos.<\/p>\n The researchers found that the e-tattoos performed comparably well at detecting brainwaves with minimal noise.<\/p>\n After six hours, the gel on the conventional electrodes started to dry out.<\/p>\n More than a third of the electrodes failed to pick up any signal, although most of the remaining electrodes had reduced contact with the skin, resulting in less accurate signal detection.<\/p>\n However, the e-tattoo electrodes showed stable connectivity for at least 24 hours.<\/p>\n The research team also tweaked the ink\u2019s formula and printed e-tattoo lines that run down to the base of the head from the electrodes to replace the wires used in a standard EEG test.<\/p>\n Co-corresponding author Professor Ximin He, of the University of California, Los Angeles<\/a>, said: \u201cThis tweak allowed the printed wires to conduct signals without picking up new signals along the way.”<\/p>\n The researchers then attached much shorter physical wires between the tattoos to a small device that collects brainwave data.<\/p>\n They plan in future to embed wireless data transmitters in the e-tattoos to achieve a fully wireless EEG process.<\/p>\n![](\"https:\/\/www.saipantribune.com\/wp-content\/uploads\/images\/imgupload\/6f6be642bcf0b2d461149d6854e42707.jpg\")
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