A flexible biosensor for efficiently glucose monitoring in sweat based on copper nanoparticles modified PHEMA hydrogel

[Display omitted] •A novel Cu/Fe complex conductive hydrogel for non-invasive sweat glucose detection was constructed.•The hydrophilic nature of the hydrogel facilitates the easier diffusion of glucose, thereby improving the sensing efficiency.•Owing to the outstanding self-healing property of the hydrogel, the sensor is capable of tolerating deformation and damage.•The biosensor exhibits a wide glucose range (0–0.2 mM and 0.2–4 mM) and low detection limit (9.99 μM). Wearable electrochemical sensors for glucose analysis hold significant potential for non-invasive monitoring of sweat biomarkers. However, the complex and expensive preparation process has limited the application of these sensors. In this study, we proposed an electrochemical glucose biosensor based on poly (2-hydroxyethyl methacrylate) (PHEMA) hydrogel initiated via iron ion and phenol hydroxyl groups. Copper nanoparticles are then incorporated into the hydrogel, enhancing the conductivity and electrocatalytic performance of the hydrogel electrode. The composite hydrogel, characterized by its rich metal coordination and hydrogen bonds, demonstrated remarkable cyclic adhesion properties, stretchability, and self-healing capability. Subsequently, this hydrogel is modified onto a screen-printed electrode (SPE) to create an in vitro skin patch for glucose detection in human sweat. The biosensor exhibits a wide linear range for glucose concentration of 0–0.2 mM and 0.2–4 mM, with low detection limit of 9.99 μM. The sensor exhibits good stability, selectivity and flexibility, and demonstrates a strong correlation with glucose measurements obtained from real sweat using a glucose assay kit. This sweat sensor holds great development potential, providing broad prospects for future non-invasive detection applications.