Ultrasensitive electrochemical sensor for monitoring glucose in sweat based on TaAuO-graphene nanobelt nanocomposite with excellent catalytic activity and specificity.

The limited sensitivity and selectivity of conventional electrochemical sensors impede their practical utility in monitoring dynamic glucose fluctuations in human sweat. Herein, we present a robust coordination-driven strategy for synthesizing TaAuO-graphene via integration of arginine and serine-functionalized and boron-doped graphene quantum dot (RSB-GQD). Initially, tantalic acid and chloroauric acid sequentially react with RSB-GQD to form stable Ta/Au-RSB-GQD complex, which is subsequently thermally annealed. The resultant TaAuO-graphene exhibits a hierarchical belt-like nanostructure featuring interconnected tunnels, ultrathin sheet morphology, abundant low-valent Ta species, and graphene-mediated surface modification. This unique architecture synergistically enhances electron/ion transport kinetics, maximizes the accessibility of catalytically active Au sites, and strengthens interfacial interactions with polar electrolytes. Crucially, the hybridization of TaO and Au atomic orbitals induces electronic structure reconstruction, significantly boosting both catalytic activity and glucose-specific recognition. Electrochemical evaluations reveal that TaAuO-graphene demonstrates a 2.6-fold higher catalytic activity compared with conventional Au-graphene systems. Leveraging these advantages, we fabricate an enzymatic electrochemical glucose sensor that exhibits exceptional sensitivity, with a linear current response at 0.5 V spanning 0-500 μM and detection limit of 3.6 × 10 M (S/N = 3). The sensor further demonstrates remarkable selectivity against common interferents, long-term stability, and reproducibility, establishing a reliable platform for non-invasive sweat glucose monitoring.