Electrostatic interaction induced enhancement of conductive hydrogel for motion detection and targeted identification of ascorbic acid in sweat.

Multifunctional flexible sensors with applications in the fields of monitoring human motion and detecting ascorbic acid (AA) in sweat have received more and more attention. Carbon material-based hydrogels show great potential to construct multifunctional flexible sensors, while sensitive and selective detection of AA is still challenging. Herein, the tetraphenyl porphyrin@carbon fiber (TPP@CF) hydrogels were designed for enhancing identification of AA in sweat by an electrostatic interaction strategy. TPP is incorporated in CF to ensure the sensitivity of detecting AA. Hexadecyl trimethyl ammonium bromide (CTAB) with positive charge is adding for not only enabling selective detection of negatively charged AA, but also enhancing dispersion of TPP@CF, and concurrently improving the mechanical properties and electrical conductivity of hydrogels. The fabricated multifunctional hydrogel sensors exhibit preferable mechanical strength (1.41 MPa) and high conductivity (0.17 S/m), enabling accurate detection of AA with a low detection limit of 1.31 μM. Notably, it enables non-invasive, real-time acquisition of health-relevant biomarkers from human sweat, thereby opening an avenue for personalized health management.