A wearable, cotton thread/paper-based microfluidic device coupled with smartphone for sweat glucose sensing

Development of wearable devices for in situ monitoring biological analytes in sweat has been fueled up in the past few years. Although microfluidic thread/paper-based analytical device (μTPAD) fulfills the requirements of wearable systems on flexibility and biocompatibility, it has not been employed as a sensing system for the in situ sweat analysis. In this work, we developed a wearable μTPAD containing a cotton thread and a functionalized filter paper for non-invasive, quantitative and in situ monitoring of human sweat glucose with the assistance of a smartphone. The oxygen plasma was applied to tailor the wicking property of the cotton thread. Amounts of enzymes and reagents on the filter papers were optimized to achieve the high-performance colorimetric sensing of glucose. The as-prepared device possesses a dynamic range of 50–250 μΜ and a detection limit of ~ 35 μΜ. Because of its great wearability and compatibility with conventional textile industry, the μTPAD was integrated with an arm guard to sensitively detect glucose in human sweat. This work may provide a low-cost, easy to use wearable device based on the cotton thread and filter paper for human sweat analysis.