Composite Nanofiber Membrane-Based Microfluidic Fluorescence Sensors for Sweat Analysis.

Microfluidic chips play a crucial role in wearable sensors for sweat collection. However, previously reported wearable microfluidic chips, such as those based on poly(dimethylsiloxane) (PDMS) and paper, encounter sweat accumulation at the skin-sensor interface in practical applications, which consequently affects both sensing stability and wearing comfort. Herein, we propose a composite nanofiber membrane (CNMF)-based microfluidic chip for in situ sweat collection. The CNMF with directional water transport capability was integrated with patterned PDMS to prepare microfluidic chips. On one hand, sweat can be automatically transported to the analysis area along the designed pathway. On the other hand, sweat transfers from the hydrophobic membrane close to the skin to the hydrophilic membrane, effectively avoiding sweat accumulation and facilitating a comfortable skin microenvironment. Subsequently, we constructed a CNMF-based microfluidic fluorescence sensor for the analysis of multiple targets in human sweat. A portable 3D-printed device was employed for the visual signal output. Results indicated that the microfluidic sensor exhibits excellent reliability for collecting and analyzing sweat. This work provides new insights into the construction of wearable microfluidic chips with enhanced wearing comfort.