78 research outputs found

    Potassium‐ion‐selective fluorescent sensors to detect cereulide, the emetic toxin of B. cereus, in food samples and HeLa cells

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    We report the development of new chemical probes for cereulide, a toxic metabolite produced by specific strains of Bacillus cereus, through displacement of potassium cations from a preformed specific complex and a subsequent change in the fluorescence emission. For this purpose, we designed fluorescent probes for potassium cations that were suitable for displacement assays with cereulide from organic extracts. The fluorescence detection of natural cereulide in rice samples was achieved by using synthetic cereulide as a reference and a potassium fluorescent reporter, and this was found to be useful as a portable and fast method for the in situ detection of cereulide in food extracts. To study the fate of cereulide in live cells, we designed a procedure that was suitable for live‐cell microscopy imaging of HeLa cells by comparing the cellular location of the potassium fluorogenic probe, which stained intracellular endolysosomes, in the absence and presence of cereulide; we concluded that in the presence of cereulide, the fluorescence of the probe was decreased because of complexation of the potassium ions by cereulide.Ministerio de Econom&a y Competitividad, Spain (Projects CTQ2015-71353-R and AES-PI16/000496), Junta de Castilla y Lejn, Consejer&a de Educaci jn y Cultura y Fondo Social Europeo (Project BU232U13), and the European Commission, Seventh Framework Programme (Project SNIFFER FP7-SEC-2012–312411

    Dipolar Photosystems: Engineering Oriented Push-Pull Components into Double- and Triple-Channel Surface Architectures

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    Push–pull aromatics are not popular as optoelectronic materials because their supramolecular organization is difficult to control. However, recent progress with synthetic methods has suggested that the directional integration of push–pull components into multicomponent photosystems should become possible. In this study, we report the design, synthesis, and evaluation of double- or triple-channel architectures that contain π stacks with push–pull components in parallel or mixed orientation. Moreover, the parallel push–pull stacks were uniformly oriented with regard to co-axial stacks, either with inward or outward oriented push–pull dipoles. Hole-transporting (p) aminoperylenemonoimides (APIs) and aminonaphthalimides (ANIs) are explored for ordered push–pull stacks. For the co-axial electron-transporting (n) stacks, naphthalenediimides (NDIs) are used. In double-channel photosystems, mixed push–pull stacks are overall less active than parallel push–pull stacks. The orientation of the parallel push–pull stacks with regard to the co-axial NDI stacks has little influence on activity. In triple-channel photosystems, outward-directed dipoles in bridging stacks between peripheral p and central n channels show higher activity than inward-directed dipolar stacks. Higher activities in response to direct irradiation of outward-directed parallel stacks reveal the occurrence of quite remarkable optical gating

    Electron-deficient fullerenes in triple-channel photosystems

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    Fullerenes of increasing electron deficiency are designed, synthesized and evaluated in multicomponent surface architectures to ultimately build gradients in LUMO levels with nine components over 350 mV down to -4.22 eV

    Synthesis of Black Phosphorene/P-Rich Transition Metal Phosphide NiP<sub>3</sub> Heterostructure and Its Effect on the Stabilization of Black Phosphorene

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    Black phosphorus (BP), as a direct band gap semiconductor material with a two-dimensional layered structure, has a good application potential in many aspects, but the surface state of it is extremely unstable, especially that of single-layer black phosphorus. In this study, BP crystals and two-dimensional black phosphorus (2D BP) are prepared by a mechanical ball-milling–liquid-phase exfoliation method. The X-ray diffraction (XRD) spectrum and high-resolution transmission electron microscopy (HRTEM) results showed that red phosphorus (RP) successfully turned to BP by the mechanical ball-milling method. The spectrophotometric analysis has detected absorption peaks at 780 nm, 915 nm, and 1016 nm, corresponding to single, double, and three-layer BP bandgap emission. A simple solvothermal strategy is designed to synthesize in-plane BP/P-rich transition metal phosphide (TMP) heterostructures (BP/NiP3) by defect/edge-selective growth of NiP3 on the BP nanosheets. HRTEM analysis indicates that the metal ions are preferentially deposited on the defects of 2D BP such as edges and unsaturated sites, forming a 2D BP/NiP3 in-plane heterojunction
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