Flexible microcolumn array-based silk fibroin for sweat glucose monitoring

Flexible sweat sensors possess the special potential for continuous non-invasive monitoring of human blood glucose. We put forward a flexible microcolumn array sensor, which is designed for health monitoring by means of detecting glucose levels in sweat and capturing physiological signals related to human movement. With the combination of silk fibroin (SF), waterborne polyurethane (PU), and multi-walled carbon nanotubes (MWCNT), this microcolumn film electrode is able to effectively function as a strain sensor benefiting from the superior mechanical performance of PU. The obtained strain sensor exhibits a rapid response time of 0.3s and demonstrates robust stability over 500 cycles, efficiently capturing human pulse and hand movement signals. Prussian Blue (PB) is deposited on the surface of the microcolumn electrode and glucose oxidase (GOx) is sprayed to construct a glucose sensor that can accurately detect glucose in human sweat. The microcolumn array sensor shows and exhibits an excellent sensitivity of 35.28 μA/mM·cm² within a dynamic range of 0.1-1 mM, and a limit of detection (LOD) of 0.004 mM, which reveals outstanding glucose sensing performance. This microcolumn array sensor demonstrates the potential of silk fibroin in crafting portable, high-performance electrochemical wearable medical devices.