Search

A high-performance non-enzymatic glucose sensor based on hybrid metal-oxides is proposed. Dumbbell-shaped double-shelled hollow nanoporous CuO/ZnO microstructures (CuO/ZnO-DSDSHNM) were prepared via the hydrothermal method using pluronic F-127 as a surfactant. This structure is studied by various physicochemical characterizations such as scanning electron microscopy, X-ray diffraction spectroscopy, inductively coupled plasma atomic emission spectroscopy, elemental mapping techniques, X-ray photoelectron spectroscopy, and transmission electron microscopy. This unique CuO/ZnO-DSDSHNM provides both a large surface area and an easy penetrable structure facilitating improved electrochemical reactivity toward glucose oxidation. The prepared CuO/ZnO-DSDSHNM was used over the glassy carbon electrode (GCE) as the active material for glucose detection and then coated by Nafion to provide the proposed Nafion/CuO/ZnO-DSDSHNM/GCE. The fabricated glucose sensor exhibits an extremely wide dynamic range from 500 nM to 100 mM, a sensitivity of 1536.80 µA mM−1 cm−2, a low limit of detection of 357.5 nM, and a short response time of 1.60 s. The proposed sensor also showed long-term stability, good reproducibility, favorable repeatability, excellent selectivity, and satisfactory applicability for glucose detection in human serum samples. The achieved high-performance glucose sensing based on Nafion/CuO/ZnO-DSDSHNM/GCE shows that both the material synthesis and the sensor fabrication methods have been promising and they can be used in future researches. [ABSTRACT FROM AUTHOR]

Electrospun carbon nanofibers (ECNFs) have many qualities that make them attractive for applications in various fields of technology. For many applications, it is necessary to modify the surface of CNFs by chemical functionalization. Here, a systematic functionalization of polyacrylonitrile (PAN)-based ECNFs by oxidation in concentrated nitric acid was examined. The effects of oxidation on the microstructural, electrical, and mechanical characteristics have been studied. The Fourier transform infrared spectroscopy results revealed the time-dependent functionalization of ECNFs. However, according to the scanning electron microscopy, there was no considerable change in the surface morphology of CNFs due to functionalization. The microstructures as well as electrical and mechanical properties were severely dependent on oxidation duration according to X-ray diffraction and Raman spectroscopies as well as conductivity and mechanical strength measurements, respectively. Increase in oxidation duration led to more structural disorders and noticeable decrease in electrical conductivity and mechanical strength. [ABSTRACT FROM AUTHOR]