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This paper presents a facile method to fabricate nanostructured copper-oxide (Cu2O/CuO) electrodes with columnar morphology for non-enzymatic glucose sensing. The electrodes were fabricated using a two-step method; first by producing Cu nanostructures through glancing angle deposition (GLAD), followed by a thermal annealing process at various temperatures. The nanostructures were characterized by X-ray diffraction and scanning electron microscopy to evaluate their structural and morphological properties. The optical properties of the electrodes were also investigated by VIS/NIR spectroscopy. Electrochemical characterization revealed that Cu2O outperformed other copper-based nanostructures, with the best sensitivity of 1394 μAcm-2 mM-1 and the lowest limit of detection (LOD) of 0.052 μM. The superior sensor also exhibits two broad linear ranges of 0.01–2 mM and 2–5 mM at the optimized potential of 0.6 V. The Cu2O electrodes demonstrate the merits of reproducibility, selectivity, fast response time, and high accuracy in measuring glucose levels in real blood serum samples.

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 59.95uAmM[?]1cm[?]2 with a low limit of detection of 1.501uM. 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%.

MicroRNAs (miRs) as biomarkers for early cancer diagnostic, were detected through a developed ultrasensitive electrochemical biosensor containing gold Nano-islands (Au-NIs) structures. Different concentrations of miR-21 (from zepto -molar to micro range) in both standard solution and blood serum samples were measured to test the sensitivity of biosensor. A high surface-area-to-volume ratio of nanostructures embellished on the FTO electrodes increases the chance of immobilization of the thiol modified capture probe (anti-miR-21 or cap-21). The Au-nanostructures surface modification and its ability to hybridize successfully and stably anti-miR-21 and miR-21 confirmed by electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) electrochemical techniques. The results showed that the linear detection range of the biosensor was from 1.0 zM to 200 nM with a limit of detection (LOD) of 0.12 zM which revealed a very high sensitivity. The selectivity of the biosensor was also investigated and confirmed by detecting miR-9 and miR-486. Corresponding results revealed that the biosensor discriminated target miR-21 from non-complementary miR-21 and showed high selectivity and specificity. Our results also revealed that this platform is a promising substrate to quantitative analysis of miR-21 in physiological samples and could be used for biomedical research and point-of-care (POC) diagnosis. Straightforward and robust Au-NIs surface fabricated without surfactant and stabilizer additive, with plenty of anchors for ssDNA immobilization, as well as well-established hybridization and immobilization procedures, plus high electron transfer rate ability in comparison to bare FTO electrodes are among attractive and suitable novelty of this study.

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−2with 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%.

The synthesization of Cu2O thin films by electrodeposition for photoelectrochemical water splitting is reported. The synthesized Cu2O samples are annealed at different temperatures between 300 and 500 °C. The XRD analysis and SEM images indicate that the sample without annealing includes Cu2O grains with pyramid shape. With annealing to more than 300 °C, due to the oxidization of the sample, a thin layer of CuO appears on the original Cu2O film and the crystalline signatures of such CuO structure increase with annealing at higher temperatures. The photoelectrochemical measurements indicate that annealing pure Cu2O by more than 300 °C, remarkably increases the photocurrent achieved from this photocathode. The effect is accompanied with considerable improvement of chemical stability of the original Cu2O electrode during water splitting. Such protection effect, which is originated from generation of CuO on the samples, increases with the annealing temperature up to 500 °C. However, the best photocurrent from the Cu2O/CuO composite is obtained from the annealing temperature of about 400 °C. The results of impedance analysis of various annealed samples indicate that annealing at a higher temperature, better charge transfer occurs both at the interface of photocathode/electrolyte and inside the photocathode. The electrodeposition of Cu2O thin films for photoelectrochemical water splitting is reported. The Cu2O samples are annealed at different temperatures (300–500 °C). With annealing, a thin layer of CuO appears on the Cu2O film. The Cu2O/CuO composite has more stability against photoelectrochemical corrosions. The stability improves with the annealing temperature, while the best photocurrent is obtained from the sample of 400 °C.