Tattoo electrodes have successfully demonstrated their performances in the monitoring of various bio-signals from the skin. They have been largely used to record electrophysiological signals, to perform sweat biochemical analysis and to monitor skin hydration level. Such electrodes can be made of only organic materials, which are highly suitable for bioelectronic applications where materials softness and plasticity are the key parameters to better interface with the epidermis. Conducting polymer tattoos are dry skin-contact sensors based on poly(3,4-ethylenedioxythiophene) : polystyrene sulfonate (PEDOT:PSS), deposited by inkjet printing, on top of a commercial temporary tattoo paper. At the sub-um thickness, the tattoo layer is capable to conformably adhere to the skin creating an imperceptible contact between the human body and the ele
ctronics. Here a comprehensive study about tattoos properties is reported. We evaluate the performance with respect to the possible perspiration. Advanced signal processing is done to analyze bioimpedance . These evaluations provides valuable input in designing ultra-thin electronic sensors for multimodal long-term human monitoring.