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The pod-like Cu 2 O nanowire arrays (denoted as Cu 2 O PLNWs/Cu foam) grown on the three-dimensional copper foam is synthesized by a low-cost and convenient method. The morphology and composition of the Cu 2 O PLNWs/Cu foam are characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction, respectively. The high conductivity of Cu foam as current collector can facilitate the charge and mass transfer, and the Cu foam with opened framework provides large amounts of anchoring sites for the deposition of Cu 2 O NWs during the synthesis of the Cu 2 O PLNWs/Cu foam. Accordingly, The Cu 2 O PLNWs/Cu foam is used as electrocatalysts for the detection of glucose and H 2 O 2 . The Cu 2 O PLNWs/Cu foam electrode shows extremely high sensitivity of 6.6807 mA mM −1 cm −2 and a low detection limit of 0.67 μM for the electrocatalytic oxidation for glucose. The nonenzymatic sensor also demonstrates good response toward hydrogen peroxide with high sensitivity of 1.4773 mA mM −1 cm −2 and the detection limit of 1.05 μM. Due to the excellently high sensitivity, stability and anti-interference ability, the Cu 2 O PLNWs/Cu foam will be the potential candidate for constructing practical non-enzymatic glucose and hydrogen peroxide sensors. [ABSTRACT FROM AUTHOR]

In this paper, a novel, selective and eco-friendly biosensor has been fabricated and applied for sensitive detection of antibiotic oxytetracycline (OTC). This fluorescent biosensor was based on carbon quantum dots (CDs), H 2 O 2 and Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 MNPs). Herein, we firstly demonstrated that the fluorescence of CDs decreased apparently in the presence of OTC, H 2 O 2 and Fe 3 O 4 MNPs. The fluorescence quenching of CDs not only is caused by the hydroxyl radical produced from the Fenton reaction and complexation of Fe 3 O 4 MNPs with OTC, but also might be related to the inner filter effect (IFE) between CDs and OTC, which improved the selectivity and sensitivity of the fabricated biosensor. Under the optimal experiment conditions, the relative fluorescence intensity of the CDs decreased linearly with the increasing concentration of OTC from 25 nM to 1.75 μM. The detection limit of the fabricated biosensor on OTC was 9.5 nM at a signal-to-noise ratio of 3. Compared with other current protocols, the method described here displayed a few advantages including simplicity, low cost and rapid detection. The precision and reproducibility of the proposed sensor were also acceptable Significantly, the practicality of this sensitive sensor for OTC detection in drugs was further validated, revealing the advantages of high simplicity, sensitivity and selectivity. Hence, the developed biosensor might provide a useful and practical tool for OTC determination and related food safety analysis and clinical diagnosis. [ABSTRACT FROM AUTHOR]