Constructing heterostructure on highly roughened caterpillar-like gold nanotubes with cuprous oxide grains for ultrasensitive and stable nonenzymatic glucose sensor

In this study, a metal-metal oxide heterostructure was designed and constructed by growing cuprous oxide (Cu₂O) grains on highly surface roughened caterpillar-like Au nanotubes (CLGNs) for ultrasensitive, selective and stable nonenzymatic glucose biosensors. The Cu₂O grains are tightly anchored to the surface of CLGNs by the spines, resulting in a large increase in the contact area between Cu₂O grains and the CLGNs, which facilitates the electron transport between metal and metal oxide and improves the sensitivity and stability of the sensors. The electron transfer coefficient (α) and electron transfer rate constant (k_s) for redox reaction of Cu₂O-CLGNs/GCE are found to be 0.50114 and 3.24±0.1s^-1, respectively. The biosensor shows a linear response to glucose over a concentration range of 0.1-5mM and a high sensitivity of 1215.7μAmM^-1cm^-2 with a detection limit of 1.83μM. Furthermore, the Cu₂O-CLGNs biosensor exhibited strong anti-interference capability against uric acid (UA), ascorbic acid (AA), potassium chloride (KCl) and sodium ascorbate (SA), as well as a high stability and repeatability. Our current research indicates that the Cu₂O-CLGNs hybrid electrode is a promising choice for constructing nonenzyme based electrochemical biosensors.