Electronic tattoo monitors the heart

The flexible electronic tattoo (e-tattoo) is worn on the chest and detects both a conventional electrocardiogram (ECG) and a seismocardiograph (SCG) reading.

With an e-tattoo (electronic tattoo) worn directly on the chest, heart health can be determined in two ways. First, the electronic tattoo records the electrocardiogram (ECG). It is also possible to obtain the lesser known seismocardiograph reading (SCC). The e-Tattoo was developed by researchers at the University of Texas Cockrell School of Engineering in Austin. When used in conjunction with ECG and chest vibration data, it can better assess the accuracy of ECG data.

The e-Tattoo is made of a piezoelectric polymer (polyvinylidene fuoride) and can be controlled remotely via a smartphone. There are already several e-Tattoo on the market. But these are made of non-stretch materials The electronic sensor can be worn for several days. This makes it possible to analyze measurement data of the heart over several days, which is a great advantage over the short measurements taken by a doctor.

Sensor field made of a polymer film

The Senosor field is constructed from a 28 µm thick PVDF (polyvinylidene fluoride) film and 80 nm thick electrodes made of copper and nickel, which are attached to the top and bottom sides.

The e-Tattoo project was not limited to the fabrication of the sensor and how it is attached to the chest. The piezoelectric sensors used to detect heart health are subject to unwanted motion artifacts called noise.

The developers of the e-Tattoo minimized noise by placing a pair of identical tattoos side by side. Unwanted motion artifacts were filtered out by subtracting the two identical tattoos. To guarantee the best position on the chest, 3D digital image correlation (DIC) is used. It also allows the stiffness of the substrate used to be investigated.