Multifunctional Sweat Sensors Using Semiconductor Fibers Based on Two‐Dimensional Nanomaterials

Sweat monitoring offers real‐time insights into physiological conditions such as hydration, muscle fatigue, and metabolic status. However, conventional sweat sensors often face challenges associated with unstable skin contact and insufficient sampling. In this study, a fiber‐based wearable sensing platform is proposed, which incorporates semiconducting molybdenum disulfide (MoS 2 ) and polylactic acid (PLA) composite fibers fabricated via wet spinning. By exploiting the high surface‐to‐volume ratio and n‐type semiconducting nature of the MoS 2 network, the sensor selectively detects major biomarkers including electrolytes (Na + and K + ) and metabolites (lactic acid and NH 4 + ) via distinct electrostatic screening and charge trapping mechanisms. Furthermore, the intrinsic capillary action and thermal insulation of the fibers ensured reliable sweat collection without the requirement for external power. Additionally, the composite fiber exhibits piezoresistive capabilities, enabling simultaneous pressure monitoring to track physical motion. Multifunctional sensing facilitates the early diagnosis of metabolic disorders and the precise tracking of athletic performance. The developed fiber‐based sensor provides a robust textile‐integrated solution for next‐generation personalized healthcare monitoring.