Sequential biofluid sampling microfludic multi-sensing patch for more accurate sweat analysis under sedentary condition

Wearable sweat sensors hold immense potential for continuous monitoring of physiological parameters non-invasively. However, environmental and physiological changes may lead to reduced sweating, making iontophoresis-induced sweat analysis a more attractive and feasible option for easy-sampling in daily life. Nevertheless, this approach also faces challenges such as analyte concentration being affected by sweat rate variance and sweat dilution. To address these challenges, we have developed a multi-sensing patch for iontophoresis-stimulated sweat detection under sedentary conditions. The platform integrated electrochemical sensor arrays with microfluidic components for a rapid collection and in situ measurement including metabolites (glucose and ethanol) and electrolytes (Na+ and pH) in sweat. The designed microfluidic patch, capable of sequential sweat collection, significantly improved the signal stability at low sweat rate and its performance was verified by software simulation, in vitro analysis, and on-body signal monitoring. Overall, this microfluidic sensing patch opens an exciting avenue for analyzing the perspiring condition of sedentary individuals, making it an attractive option for point-of-care testing applications.