Nanofiber-shaped Co₃O₄@In₂O₃ composite for high-performance enzymeless glucose sensing

Cobalt tetraoxide (Co3O4) holds great potential for enzymeless glucose detection due to its strong redox capabilities. However, its poor electrical conductivity limits the charge transfer and hence weakens its catalytic activity when utilized as an electrode in electrochemical sensors, such as an enzymeless glucose sensor. In this study, we developed an indium oxide (In2O3)-wrapped Co3O4 nanofibers (Co3O4@In2O3 NFs)-based electrochemical sensor for the enzymeless detection of glucose, with an ultra-low limit of detection (LoD) of 8.85 nM (S/N = 3), a wide detection range from 10 nM to 118 μM, and a high sensitivity of 1197.5 μA mM-1 cm-2. In addition, this sensor exhibits good selectivity, reproducibility, and long-term stability for over 30 days. The sensing performance of bare Co3O4 NFs towards glucose has been significantly enhanced by incorporating them within highly conductive In2O3, which is mainly attributed to the synergistic combination of the electrocatalytic activity of Co3O4 NFs, as the delicately designed core, and the excellent conductivity of In2O3, as the shell. Thus, this novel modified Co3O4@In2O3 NFs electrochemical composite has huge potential to be further developed for enzymeless glucose analysis in practical clinical settings.