Graphene electronic tattoo (GET) is a group of ultrathin stretchable dry sensors for measuring electrocardiogram (ECG), electromyogram (EMG), electroencephalogram (EEG), skin temperature, and skin hydration. Because of low thickness (463 ± 30 nm) and ultra low areal mass density of GET, it forms conformal contact to the skin and stays intact without any adhesive or tape just via van der Waals force. A bare GET is able to stay attached to skin for several hours without fracture or delamination. With liquid bandage coverage, a GET may stay functional on the skin for up to several days. The optical transparency of GET is ∼85%, and it is more stretchable (40%) than human skin (10 to 30%). The GET can be directly laminated on human skin just like a temporary tattoo and can fully conform to the microscopic morphology of the skin.
