Fully printed all-polymer tattoo/textile electronics for electromyography

Driven by the ever-growing needs for developing low cost, easy-to-use, noninvasive diagnostic tools, biomedical devices that can be integrated on human skin or textiles have begun to emerge. These "wearable" devices should couple electronics directly to the human skin and detect a variety of biologically relevant signals such as the neuromuscular activity. In this work, we present a simple, low cost and customizable device to perform electromyography (EMG) measurements based on electronics fabricated on a tattoo paper. The electrodes are based on the conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) and inkjet-printed on the conformable tattoo paper. Addressing the integration challenge common for such flexible electronic devices, we connect the tattoo electrodes to the acquisition system through a textile in the form of a wristband comprising of printed PEDOT:PSS contacts. While the textile wristband conforms around the "tattooed" skin, it enables a reliable contact with the electrodes beneath. We show that this tattoo/textile electronics system is able to detect the biceps activity of the arm during muscle contraction for a period of seven hours, with comparable performance to conventional biopotential electrodes, without the use of gels or expensive metallic materials. Combining the tattoo electronics with the electronic textile constitutes a versatile solution for the communication of skin-like electrodes with external electronics, renders a reliable system for detecting biopotential signals critical for myoelectric prosthesis, muscle injury prevention and/or detection.