“…Consequently, wearable devices must answer new constraints to be a winning technology, because besides being reliable when compared with the state-of-the-art conventional sensors, they should be designed to be as less invasive as possible, in view of reaching a wear-and-forget functionality. To satisfy these requirements, the literature proposes different design strategies that are usually based on embedding the sensing element in real-life objects, such as contact lenses [ 3 , 4 ], tattoos [ 5 , 6 , 7 ], garments [ 8 , 9 ], dental appliances [ 10 ] and medical dressings [ 11 ]. Of course, these gadgets should detect the target compounds in a specific biofluid in their proximity, and thus mouth guard sensors operate in saliva, textile sensors in sweat, and contact lenses in tears.…”