“…Changes in conductivity are often employed as the sensing mechanism [216][217][218][219][220][221]259,288,296], while fluorescence quenching [223,260], color changes [227], pH changes [201], and mechanical deformation/pressure changes [231,[267][268][269][270] have also been employed. Sensors have been developed for gases [216,217,[219][220][221][222]259,296], humidity [224,225,[287][288][289], explosives [218], chemical warfare agents [260,289], ions [226,227,261], and, as mentioned above, a wide variety of bioactive species such as additives, antigens, and biomolecules for detection of medical conditions. Wearable sensors have been developed to detect harmful substances, analyze bodily fluids, monitor vital signs, and record motion [201,231,[266][267][268][269][270].…”