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The core–shell non-enzymatic glucose sensors are generally fabricated by chemical synthesis approaches followed by a binder-based immobilization process. Here, we have introduced a new approach to directly synthesis the core–shell of Au@Cu and its Au@CuxO oxides on an FTO electrode for non-enzymatic glucose detection. Physical vapor deposition of Au thin film followed by thermal annealing has been used to fabricate Au nanocores on the electrode. The Cu shells have been deposited selectively on the Au cores using an electrodeposition method. Additionally, Au@Cu2O and Au@CuO have been synthesized via post thermal annealing of the Au@Cu electrode. This binder-free and selective-growing approach has the merit of high electrooxidation activity owing to improving electron transfer ability and providing more active sites on the surface. Electrochemical measurements indicate the superior activity of the Au@Cu2O electrode for glucose oxidation. The high sensitivity of 1601 μAcm−2 mM−1 and a low detection limit of 0.6 μM are achieved for the superior electrode. Additionally, the sensor indicates remarkable reproducibility and supplies accurate results for glucose detection in human serums. Moreover, this synthesis approach can be used for fast, highly controllable and precise fabrication of many core–shell structures by adjusting the electrochemical deposition and thermal treatment parameters. [ABSTRACT FROM AUTHOR]

A stable and sensitive non-enzymatic glucose sensor is proposed based on the hybrid thin films of copper on acetanilide/ITO-PET. The electrode was fabricated through a two-step synthesis process including electrochemical deposition of acetanilide on ITO-PET, subsequent by physical vapor deposition of a copper film. The electron microscopy images showed the formation of a porous structure on the ITO-PET sheet. Such modified electrode presents a high sensitivity of 59.95μAmM-1cm-2 with a low limit of detection of 1.501μM. This glucose sensor exhibits a range of linear response between 2 to 12mM. In addition, it includes a variety of advantages as high flexibility, the possibility for scale-up production, low material consumption, low cost, excellent reproducibility, high selectivity, good sensitivity and short response time. Finally, the glucose determination of different human blood serums indicates that the deviation of this sensor from the clinical measurements is less than 5%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu-Ag nanostructures are fabricated by combining GLAD and galvanic replacement. • Various morphologies are fabricated by controlling galvanic replacement parameters. • Ag nanoshells deposited on Cu nanocolumns show the best electrocatalytic performance. • Best electrodes have the sensitivity of 3802 μAcm−2 mM−1 and detection limit of 1.33 μM. A scalable and repeatable synthetization method is introduced to fabricate Cu-Ag bimetallic nanostructures as a stable, robust, fast-response and enzyme-free glucose sensor. Cu nanocolumns were constructed on the FTO substrate using the glancing angle deposition (GLAD). Then a thin layer of Ag is deposited on the Cu nanocolumns through a galvanic replacement reaction. The Cu-Ag nanostructures with different morphologies were developed by tuning the concentration and the reaction time of the galvanic replacement process. Various electrochemical characterizations, including cyclic voltammetry and electrochemical impedance spectroscopy (EIS), were performed to determine the superior electrocatalytic activity of the electrodes. The results reveal that the superior electrocatalytic performance toward glucose oxidation was achieved with Cu-Ag fabricated under the AgNO 3 concentration of 5 mM and with a reaction time of 30 s. The sensor exhibits a fast response of ∼2 s with an excellent sensitivity of 3802 and 712 μAcm−2 mM−1 in two wide linear ranges of 0.01–3 mM and 3–8 mM and an optimum potential of 0.65 V. The proposed Cu-Ag sensor showed considerable enhancement of electrocatalytic activity compared to Cu or Ag monometallic structures due to the synergistic effect. In addition, the current bimetallic sensor regarding its outstanding precision and its reproducibility provides a promising method for large scale fabrication of non-enzymatic glucose sensors. [ABSTRACT FROM AUTHOR]

• We have produced porous Cu nanostructures by glancing angle deposition. • The Cu nanostructures deposited on FTO provide a sensitive glucose sensor. • Impressive electrochemical responses from the electrode were measured. • A high glucose detection sensitivity of 1862 μAcm−2 mM−1 was obtained. • The fabrication method proposes excellent reproducibility and selectivity. In this work, we have proposed a proper method to fabricate porous Cu nanostructured electrodes for non-enzymatic glucose detection. The glancing angle deposition (GLAD) has been used to produce Cu nanostructures on the FTO substrates. To optimize the sensing performance of the electrode, the effects of vapor deposition angle and azimuthal substrate rotation speed have been investigated. As a result, the superior electrocatalitic activity is obtained under the deposition angle of θ = 82° and the substrate rotation speed of φ ̇ = 20 rpm, respectively. By controlling the GLAD deposition parameters, an excellent sensing performance against glucose with a high sensitivity of 1862 μAcm−2 mM−1, a low detection limit of 0.048 μM and two wide linear ranges of detection of 10 μM–2 mM and 2–8 mM have been achieved at the applied potential of 0.5 V. Considering the high selectivity, excellent reproducibility and accurate measuring of the glucose levels in human serums, the proposed Cu-based sensor has a remarkable potential for large-scale production as a non-enzymatic glucometer. [ABSTRACT FROM AUTHOR]