Stretchable Gold Fiber-Based Wearable Electrochemical Sensor toward pH Monitoring
Sweat pH is a key health indicator related to metabolism and homeostasis level through hydrogen ion concentration in biological bio-fluid. Therefore, increasing research efforts have been directed to develop wearable pH sensors towards continuous non-invasive monitoring sweat pH values in the out-of-hospital environments. Here, we report on a stretchable gold fiber-based electrochemical pH sensor based on our recently developed elastomer-bonded gold nanowire coating technology. The densely packed gold film offer superior strain-insensitive conductivity, high stretchability and large electrochemical active surface area (EASA). By electrodepositing polyamine (PANI) and Ag/AgCl onto the gold fibers, we could selectively detect pH based on open circuit potentials in an ion-selective electrode design. The obtained fiber-based pH sensors feature a great sensitivity (60.6 mV/pH), high selectivity against cationic interference and a high stretchability (up to 100% strain). One of the attributes for the fiber-based sensors is that they can be weaved into textile, holding great potential for integration into everyday clothing for “unfeelable” personal health monitoring.