Low-cost,μm-thick,tape-free electronic tattoo sensors with minimized motion and sweat artifacts

Electronic tattoos(e-tattoos),also known as epidermal electronics,are ultra-thin and ultra-soft noninvasive but skin-conformable devices with capabilities including physiological sensing and transdermal stimulation and therapeutics.The fabrication of e-tattoos out of conventional inorganic electronic materials used to be tedious and expensive.Recently developed cut-and-paste method has significantly simplified the process and lowered the cost.However,existing cut-and-paste method entails a medical tape on which the electronic tattoo sensors should be pasted,which increases tattoo thickness and degrades its breathability.To address this problem,here we report a slightly modified cut-and-paste method to fabricate low-cost,open-mesh e-tattoos with a total thickness of just 1.5μm.E-tattoos of such thinness can be directly pasted on human skin and conforms to natural skin texture.We demonstrate that this ultra-thin,tape-free e-tattoo can confidently measure electrocardiogram(ECG),skin temperature,and skin hydration.Heart rate and even respiratory rate can be extracted from the ECG signals.A special advantage of such ultra-thin e-tattoo is that it is capable of high-fidelity sensing with minimized motion artifacts under various body movements.Effects of perspiration are found to be insignificant due to the breathability of such e-tattoos.