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Well aligned Pt/Au alloy nanowire arrays are successfully synthesized and used as the substrate for the construction of phosphate biosensors. Pyruvate oxidase is immobilized onto the nanowire surface together with co-factors via cross linking approach. Morphology, composition, structure and chemical state of the nanowires are characterized by SEM, TEM, EDS and XPS, and the electrochemical behaviors of the as-prepared phosphate biosensors are investigated by cyclic voltammogramic and chronoamperometric techniques. Especially, the influence of the composition and aspect ratio of Pt/Au alloy nanowire arrays on the response of phosphate biosensors are studied as well. The present phosphate biosensor shows a high sensitivity of 50.5 µA ⋅cm-2 ⋅mM-1 and a wide linear range between 248 and 1456 µM toward the detection of phosphate. In addition, the biosensor also exhibits good selectivity and stability, which promises great potential in phosphate detection applications. [ABSTRACT FROM AUTHOR]

A hybrid flow injection-nanobiosensor system for the detection of glucose at low potential is presented in this paper. For the fabrication of the biosensor, highly ordered gold nanowire arrays (AuNWAs) are synthesized by direct electrodeposition in combination with template approach. Glucose oxidase and horseradish peroxidase are immobilized on the surface of the resultant AuNWAs by cross-linking with glutaraldehyde (GLA) and bovine serum albumin (BSA). In combination with a flow injection system, the biosensor demon* strate high performance in glucose detection with a sensitivity of 25.34 µA · cm-2 · mM-1, a linear range between 5 and 1000 µM, a detection limit of 1 µM, and a sample throughput of 45 h-1. High selectivity against uric acid, nitrate and chloride ions is also achieved. In addition, it shows good reproducibility, repeatability and stability, which are beneficial for the practical applications in glucose detection. Finally, the developed nanobiosensor is applied to the detection of glucose in river water and the biosensor presents good performance with a relative standard deviation of 1.33% and a recovery rate of 100.4~102.9%. [ABSTRACT FROM AUTHOR]

Well aligned TiO2 nanotube arrays are used as photoelectrochemical sensor for organic compounds detection due to their excellent photocatalytic performance. The high background photocurrent and low current response to trace addition of organics restrain the detection performance of the photoelectrochemical sensor. Deposition of Bi nanoparticles onto the nanotube arrays by photocatalytic reduction of Bi3+ ions is found to decrease the background photocurrent and increase the current response effectively at the same time. Scanning electron microscope, high resolution transmission electronmicroscope and X-ray photoelectron spectrometer are used to characterize the structure, morphology and component of the Bi/TiO2 nanotube arrays. The concentration of Bi3+ ions and deposition parameters are optimized to achieve the best detecting performance. When glucose is used as target organics, the photoelectrochemical sensor can achieve a sensitivity of 0.3 µA/µM with a linear range of 0 to 1500 µM. The detection limit is calculated by triple signal noise ratio to be 4.5 µM. The mechanism of enhancing oxidation of organics is ascribed to the electrons transfer and the surface electrochemical reactions during the photoelectrochemical process. [ABSTRACT FROM AUTHOR]