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An array consisting of homogeneous NiCoS hollow core-shell nanoneedles was fabricated and is shown to enable sensitive electrochemical determination of dopamine (DA). The array was grown directly on a nickel foam (NF) substrate by a two-step hydrothermal process. The hierarchical nanoarray consists of a homogeneous NiCoS nanoneedle core and a NiCoS nanosheet shell. A 3-dimensional micro/nano structure is formed due to the presence of the micropores of the NF. The electrode was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Compared to a plain NF electrode, the NiCoS-modified NF electrode displays higher electrocatalytic activity for the oxidation of DA by differential pulse voltammetry (DPV). The sensor, best operated at a typical working voltage of 134 mV (vs. saturated calomel electrode), has a linear response in the 0.5-100 μM DA concentration range and a 0.2 μM detection limit (at S/N = 3). The electrode is selective over ascorbic acid and uric acid. Graphical abstract Schematic presentation of an electrochemical sensor for selective determination of dopamine based on the use of a homogeneous NiCoS hollow core-shell nanoneedle array on nickel foam.

With specific structures and unique features, biological ion channel proteins play crucial roles in many life processes of living organisms. Inspired by the biological ion channel proteins, researchers have developed a variety of artificial nanochannels to explore the mechanisms of selective ion transport and achieve applications in molecular filters, biosensors, and energy conversion devices. The ion transport behavior in nanochannels is mainly governed by the interaction between ions and the nanochannels interface. Herein, the structures, fabrication methods, and ion transport properties of biomimetic solid-state ion nanochannels are reviewed, with emphasis on the transport performance and mechanism of nanochannels. In addition, the current challenges faced and the future outlooks of these solid-sate ion nanochannels for practical applications are discussed.