The dependence of Cu2O morphology on different surfactants and its application for non-enzymatic glucose detection

Construction of a novel nano-enzyme for ultrasensitive glucose detection with surface-enhanced Raman scattering

Fabricating more sensitive, stable and low-cost nanomaterials for the detection of glucose is important for the disease diagnosis and monitoring. Herein, we established a nanocomposite (polypyrrole bridging GO@Au@MnO₂) as a novel surface-enhanced Raman scattering (SERS) nanoprobe for the quantitative detection of glucose in trace serum. Each component in the nanocomposites played an irreplaceable role in SERS detection of glucose. Polypyrrole (PPy) could act as Raman signal and extra SERS signal molecules didn't need to be introduced; Graphene oxide (GO) and gold nanoparticles (Au NPs) could enhance Raman signal of PPy; Au NPs also acted as glucose oxidase, which can oxidize glucose to produce gluconic acid and hydrogen peroxide(H₂O₂); Manganese oxide (MnO₂) further enhanced Raman signal of PPy and responded to hydrogen peroxide, which will induce the decrease of Raman intensity of PPy. Thus, glucose can be quantified according to Raman signal output of PPy, which displayed a liner range from 1 to 10 μM, with detectable limit of 0.114 μM. Because of the merits in sensitivity, convenience and versatility, the novel method shows large potential space for disease-related substance detection in the future.

In-situ construction of Au/Cu2O nanowire arrays for sensitive glucose sensing

Architecture design is widely regarded as a rational strategy to enhance the sensing performance of electrocatalysts. Herein, the novel three-dimensional hybrids based on Au and Cu₂O were successfully synthesized via steps of in-situ growth, including anodic oxidation, annealing and galvanic displacement. Cu₂O appeared in the morphology of nanowire array on conductive substrate, and was decorated by Au nanoparticles. Benefiting from the unique architecture and binder-free fabrication process, the Au/Cu₂O nanowire arrays possessed high conductivity and abundant exposed active sites, as well as facilitated the direct electron transfer among detection object, electrocatalyst and current collector. Moreover, Au/Cu₂O particles as contrast were fabricated to clarify the effect of structure on sensing ability. The Au/Cu₂O nanowire arrays drove the glucose electro-oxidation reaction with great catalytic activity, in which a potential as low as 0.4 V was needed to reach a high sensitivity of 2.098 mA mM^-1 cm^-2. The excellent selectivity, stability and reproducibility were also obtained by the sensor. Furthermore, the quantitative detection of glucose level in diluted human serum were performed and the satisfactory result make the obtained sensor have the potential for practical applications.