Given the concern over heart disease as a major health problem, researchers have been looking for alternatives to traditional electrocardiograph machines for heart monitoring. To this end, engineers at the University of Texas at Austin had developed an electronic tattoo that can be placed on the skin to measure various body responses, including heart movements.
The e-tattoo, reported in a recent issue of Advanced Science, is a stretchable, lightweight device that can be placed over the heart for extended periods with little or no discomfort. The e-tattoo measures cardiac health in two ways, taking electrocardiograph and seismocardiograph readings simultaneously. ECGs, of course, are a familiar method of recording the rates of electrical activity produced each time the heart beats. Seismocardiography (SCG) is a measurement technique using chest vibrations associated with heartbeats. Powered remotely by a smartphone, the e-tattoo is reportedly the first ultrathin and stretchable technology to measure both ECG and SCG.
“We can get much greater insight into heart health by the synchronous collection of data from both sources,” says Nanshu Lu, an associate professor in the departments of Aerospace Engineering and Engineering Mechanics and Biomedical Engineering.
Although soft e-tattoos for ECG sensing are not new, other sensors, such as the SCG sensor, are still made from nonstretchable materials, making them bulky and uncomfortable to wear. The tattoo developed by Lu’s team’s comprises a piezoelectric polymer called polyvinylidene fluoride, which can generate its own electric charge in response to mechanical stress. The device also includes 3D digital image correlation algorithms that are used to map chest vibrations in order to identify the best location on the chest to place the e‐tattoo.
The e-tattoo also takes a step in bringing digital health technology to heart monitoring. While traditional ECG measurements are often performed in a medical facility and only provide a sample for a few minutes, the e-tattoo can be worn for days, providing constant heart monitoring to produce a more complete profile.
Lu and her team are working to improve the device’s data collection and storage capabilities, as well as on wireless power methods for longer periods. They recently developed a smartphone app that not only stores the data safely, but can also show a heart beating on the screen in real time.
The research was funded by the Office of Naval Research, the Air Force Office of Scientific Research, the National Science Foundation and the National Institutes of Health.