Bioelectronics stickers that interface the human epidermis and collect electrophysiological data will constitute important tools in the future of healthcare. Rapid progress is enabled by novel fabrication methods for adhesive electronics patches that are soft, stretchable and conform to the human skin. Yet, the ultimate functionality of such systems still depends on rigid components such as silicon chips and the largest rigid component on these systems is usually the battery. In this work, we demonstrate a quickly deployable, untethered, battery-free, ultrathin (~5 μm) passive "electronic tattoo" that interfaces with the human skin for acquisition and transmission of physiological data. We show that the ultrathin film adapts well with the human skin, and allows an excellent signal to noise ratio, better than the gold-standard Ag/AgCl electrodes. To supply the required energy, we rely on a wireless power transfer (WPT) system, using a printed stretchable Ag-In-Ga coil, as well as printed biopotential acquisition electrodes. The tag is interfaced with data acquisition and communication electronics. This constitutes a "data-by-request" system. By approaching the scanning device to the applied tattoo, the patient's electrophysiological data is read and stored to the caregiver device. The WPT device can provide more than 300 mW of measured power if it is transferred over the skin or 100 mW if it is implanted under the skin. As a case study, we transferred this temporary tattoo to the human skin and interfaced it with an electrocardiogram (ECG) device, which could send the volunteer's heartbeat rate in real-time via Bluetooth. Surface biopotentials collected from the human epidermis contain important information about human physiology, such as muscular, heart and brain activities. This includes electromyography (EMG) 1 , Electrocardiography (ECG) 2 , and Electroencephalography (EEG) 3 , among others. The collected data has applications in health monitoring (EMG, ECG, EEG), control of prosthetics 4 or novel forms of wearable human-machine interfaces (EMG) 5,6. Wearable stickers that interface the human epidermis and acquire biopotentials for electrophysiological monitoring can be potentially transformative in digital health, since they would eventually allow a fully wireless and hassle-free data collection from the human body. Unlike traditional "wearable" technology that is composed of several rigid components, these stickers are required to be soft, flexible and stretchable. In this way, they are able to follow the dynamic morphology of the skin and remain attached to the skin during natural human movements. An ideal biomonitoring sticker is as well thin, imperceptible, comfortable and untethered. This can be also in the form of an electrical bandage or a "temporary tattoo" which bonds strongly to the human skin and acquires and transmits the information. During the last five years, some reports on fabrication and applications of ultrathin stretchable electronic films, also called epidermal electronics 7 or electronic...

Stretchable electronics stickers that adhere to the human skin and collect biopotentials are becoming increasingly popular for biomonitoring applications. Such stickers include electrodes, stretchable interconnects, silicon chips for processing and communication, and batteries. Here, we demonstrate a material architecture and fabrication technique for a multilayer, stretchable, low-cost, rapidly deployable, and disposable sticker that integrates skin-interfacing hydrogel electrodes, stretchable interconnects, and a Ag2O–Zn (silver oxide–zinc) battery. In addition, the application of a printed biphasic current collector (AgInGa) for the Ag2O–Zn battery is reported for the first time. Surprisingly, and unlike previously reported batteries, the battery capacity increases after being subjected to strain cycles and reaches a record-breaking areal capacity of 6.88 mAh cm–2 post stretch. As a proof of concept, an application of heart rate monitoring is presented. The disposable patch is interfaced with a miniature battery-free electronics circuit for data acquisition, processing, and wireless transmission. A version of the patch partially covering the patient’s chest can supply enough energy for continuous operation for ∼6 days.

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