Stretchable gold fiber-based wearable textile electrochemical biosensor for lactate monitoring in sweat

Past several years have witnessed growing interest in developing wearable biosensors for non-invasive monitoring vital signs of chemical/biological markers such as lactate. In this context, textiles can be seen as a promising platform for the integration of wearable chemical sensors due to their inherent breathability, flexibility, softness and comfortableness. Gold is regarded as a preferred active sensing material due to its excellent biocompatibility, chemical inertness and wide electrochemical window. Here, a dry-spinning method was used to fabricate stretchable, strain-insensitive and highly conductive gold fibers. Such gold fibers could be used to fabricate lactate-sensing working electrodes, reference electrode, counter electrodes and further weaved into textiles in a standard three-electrode system with a planar layout. The textile lactate biosensors showed a high sensitivity of 19.13 μA/mM cm² in phosphate-buffered solution (PBS) and 14.6 μA/mM cm² in artificial sweat. This sensitivity could be maintained under high tensile strain up to 100% without external structural design. The results presented here indicate the potential application of wearable smart textile towards non-invasive lactate monitoring.