RESUMEN
Wearable sweat sensors are emerging as promising platforms for personalized and real-time tracking of evolving health and fitness parameters. While most wearable sweat sensors focus on tracking biomarker concentration profiles, sweat secretion rate is a key metric with broad implications for assessing hydration, cardiac, and neural conditions. Here we present a wearable microfluidic sensor for continuous sweat rate measurement. A discrete impedimetric sensing scheme relying on interdigitated electrodes within a microfluidic sweat collector allows for precise and selective sweat rate measurement across a broad physiological range. Integration of a manually activated pressure pump to expel sweat from the device prevents sensor saturation and enables continuous sweat rate tracking over hours. By enabling broad range and prolonged sweat rate measurement, this platform tackles a key obstacle to realizing meaningful and actionable sweat sensing for applications in exercise physiology and medicine.
Asunto(s)
Sudor , Dispositivos Electrónicos Vestibles , Electrodos , MicrofluídicaRESUMEN
Flexible plastic substrates are widely used in printed electronics; however, they cause major climate impacts and pose sustainability challenges. In recent years, paper-based electronics has been studied to increase the recyclability and sustainability of printed electronics. The aim of this paper is to analyze the printability and performance of metal conductor layers on different paper-based substrates using both flexography and screen printing and to compare the achieved performance with that of plastic foils. In addition, the re-pulpability potential of the used paper-based substrates is evaluated. As compared to the common polyethylene terephthalate (PET) substrate, the layer conductivity on paper-based substrates was found to be improved with both the printing methods without having a large influence on the detail rendering. This means that a certain surface roughness and porosity is needed for the improved ink transfer and optimum ink behavior on the surface of the substrate. In the case of uncoated paper-based substrates, the conductivity and print quality decreased by preventing the formation of the proper and intimate ink-substrate contact during the ink transfer. Finally, the re-pulpability trials together with layer quality analysis detected very good, coated substrate candidates for paper-based printed electronics competing with or even outperforming the print quality on the reference PET foil.
RESUMEN
Recent technological advancements in wearable sensors have made it easier to detect sweat components, but our limited understanding of sweat restricts its application. A critical bottleneck for temporal and regional sweat analysis is achieving uniform, high-throughput fabrication of sweat sensor components, including microfluidic chip and sensing electrodes. To overcome this challenge, we introduce microfluidic sensing patches mass fabricated via roll-to-roll (R2R) processes. The patch allows sweat capture within a spiral microfluidic for real-time measurement of sweat parameters including [Na+], [K+], [glucose], and sweat rate in exercise and chemically induced sweat. The patch is demonstrated for investigating regional sweat composition, predicting whole-body fluid/electrolyte loss during exercise, uncovering relationships between sweat metrics, and tracking glucose dynamics to explore sweat-to-blood correlations in healthy and diabetic individuals. By enabling a comprehensive sweat analysis, the presented device is a crucial tool for advancing sweat testing beyond the research stage for point-of-care medical and athletic applications.