Enhanced Sweat Biosensing with Thread-Embedded Microfluidic Devices

BACKGROUND This study explored the integration of conductive threads into a microfluidic compact disc (CD), developed using the xurographic method, for a potential sweat biosensing platform. MATERIAL AND METHODS The microfluidic CD platform, fabricated using the xurographic method with PVC films, included venting channels and conductive threads linked to copper electrodes. With distinct microfluidic sets for load and metering, flow control, and measurement, the CD's operation involved spinning for sequential liquid movement. Impedance analysis using HIOKI IM3590 was conducted for saline and artificial sweat solutions on 4 identical CDs, ensuring reliable conductivity and measurements over a 1 kHz to 200 kHz frequency range. RESULTS Significant differences in |Z| values were observed between saline and artificial sweat treatments. 27.5 μL of saline differed significantly from 27.5 μL of artificial sweat, 72.5 μL of saline from 72.5 μL of artificial sweat, and 192.5 μL of saline from 192.5 μL of sweat. Significant disparities in |Z| values were observed between dry fibers and Groups 2, 3, and 4 (varying saline amounts). No significant differences emerged between dry fibers and Groups 6, 7, and 8 (distinct artificial sweat amounts). These findings underscore variations in fiber characteristics between equivalent exposures, emphasizing the nuanced response of the microfluidic CD platform to different liquid compositions. CONCLUSIONS This study shows the potential of integrating conductive threads in a microfluidic CD platform for sweat sensing. Challenges in volume control and thread coating degradation must be addressed for transformative biosensing devices in personalized healthcare.