Researchers have developed a mobile, noninvasive, ultrathin, stretchable, battery-operated electronic tattoo that simultaneously measures the heart’s electrical and mechanical activity, offering a new method of diagnosing and monitoring heart disease.
New ways of diagnosing heart disease, one of the leading causes of death worldwide, are always welcome, particularly if they don’t require attendance at a hospital or clinic. Enter the electronic tattoo, or e-tattoo, which is gaining popularity as a means of tracking important biomarkers.
The marriage of 3D- and circuit-printing technologies, e-tattoos represent next-generation wearable healthcare devices. They’re applied to the skin much like a child’s temporary tattoo, and their integrated sensors record and transmit data such as heart rate and rhythm, blood pressure, or stress levels to a smartphone or other connected device.
A team led by researchers at the University of Texas at Austin has improved their previous design, uncovered in 2019, by making their new e-tattoo wireless and mobile.
Like the earlier model, the new version of the e-tattoo continuously monitors electrical activity in the heart (electrocardiography or ECG) and the sounds made when the heart beats (seismocardiography or SCG), which gives an indication of the heart's mechanics. Heart sounds are created as blood flows through the heart's valves, causing them to open and close. Abnormal heart sounds such as murmurs may indicate problems with the heart valves.
Ordinarily, heart sounds are measured by a doctor using a stethoscope. The e-tattoo offers a way of monitoring heart sounds that doesn’t require attending a physician. Its ability to synchronously measure both electrical and mechanical information is important for diagnostic purposes, say the researchers.
“Those two measurements, electrical and mechanical, together can provide a much more comprehensive and complete picture of what’s happening with the heart,” said Nanshu Lu, corresponding author of the study. “There are many more heart characteristics that could be extracted out of the two synchronously measured signals in a noninvasive manner.”
The transparent e-tattoo is made up of a series of carefully arranged small circuits and sensors linked by stretchable connections, meaning it can mold to the wearer’s chest like a medical dressing.
At 200 micrometers, the e-tattoo is approximately the width of two human hairs. It weighs only 2.5 g and runs on a penny-sized (0.75-in/19-mm) battery that lasts more than 40 hours. What’s more, the battery can easily be changed by the wearer. The data collected is streamed wirelessly in real time to a Bluetooth-enabled device.
The researchers say that their mobile, noninvasive monitoring device has many advantages. For one thing, it doesn’t require a trip to the hospital or clinic and doesn't need to be attached to the bulky, cumbersome wired devices traditionally used for heart monitoring. Additionally, wearing a mobile device at home – instead of being monitored for short periods in a clinical setting – is more likely to pick up problems earlier, allowing for earlier intervention.
“Most heart conditions are not very obvious,” Lu said. “The damage is being done in the background, and we don’t even know it. If we can have continuous, mobile monitoring at home, then we can do early diagnosis and treatment, and if that can be done, 80% of heart disease can be prevented.”
The research team tested their e-tattoo on five healthy patients in their everyday environments and found it provided accurate measurements with a low error rate. The next step is for the researchers to test the device further, with a view to expanding its use to different types of patients.
The study was published in the journal Advanced Electronic Materials.
Source: University of Texas at Austin
