Porous nitrogen-doped reduced graphene oxide-supported CuO@Cu₂O hybrid electrodes for highly sensitive enzyme-free...

Constructing high-performance enzyme-free biosensors for detecting glucose is essential to preliminary diabetes diagnosis. Here, copper oxide nanoparticles (CuO@Cu₂O NPs) were anchored in porous nitrogen-doped reduced graphene oxide (PNrGO) to construct CuO@Cu₂O/PNrGO/GCE hybrid electrode for sensitive detection of glucose. Benefiting from the remarkable synergistic effects between the multiple high activation sites of CuO@Cu₂O NPs and the dramatic properties of PNrGO with excellent conductivity and large surface area with many accessible pores, the hybrid electrode possesses outstanding glucose sensing performance that is far superior to those of pristine CuO@Cu₂O electrode. The as-fabricated enzyme-free glucose biosensor displays prominent glucose sensitivity of 2,906.07 μA mM^-1 cm^-2, extremely low limit of detection of 0.13 μM, and wide linear detection of 3 μM-6.772 mM. In addition, excellent reproducibility, favorable long-term stability, and distinguished selectivity are obtained in the glucose detection. Importantly, this study provides promising results for continuous improvement of non-enzyme sensing applications.