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Responding to current limitations in paper‐based sensors and the increased interest in wearable sensors, we introduce here potentiometric sensors fully integrated into a knitted polyester fabric and their application in aqueous and biological samples. Single layer ion‐sensing devices requiring only 30 μL of sample were fabricated using wax patterning and Ag/AgCl paint. These devices give a Nernstian response to chloride over 4 orders of magnitude – an order of magnitude improvement from analogous paper‐based devices. We also report the penetration of polyester yarns with polymeric hydrophobic and hydrophilic ion‐sensing and reference membranes, all fully embedded within the fabric. These results demonstrate the promise of knitted fabrics as substrates for fully‐integrated potentiometric sensors with improved detection limits. They also elucidate the effect of pore structure on sensor fabrication and performance, thereby affecting how we understand both fabric‐ and paper‐based devices.

 

A vital part of almost every experimental electrochemical set up is the reference electrode. As the development of working and indicator electrodes progresses to sensors with greater long-term stability and efficiency, it is important for reference electrodes to keep up with that progress. In this review, the deficiencies of commonly used reference electrodes are discussed, and recent work in the development of new reference electrode designs for more stable and reliable electrochemical experiments is highlighted. This encompasses work with salt-bridge reference electrodes comprising nanoporous and capillary junctions, solid-contact reference electrodes, and ionic liquid-based reference electrodes.