Highly Ordered Metal Oxide Nanorods inside Mesoporous Silica Supported Carbon Nanomembranes: High Performance Electrode Materials for Symmetrical Supercapacitor Devices

Highly ordered metal oxide nanorods (MnO₂, SnO₂, NiO) inside mesoporous silica supported carbon nanomembranes have been applied for electroactive materials to fabricate symmetrical supercapacitors. Maximum specific capacitance of the obtained cells reaches up to 964 F g^–1 in aqueous electrolyte with energy density of 33.5 Wh kg^–1 for a 1 V voltage window, which are among the highest values in two electrodes supercapacitor cells employing similar metal oxide/carbon materials. This high performance is attributed from the synergic effect of the conductive carbon nanomembrane and well-ordered pseudocapacitive metal oxide nanorods

A Novel Approach toward Polyfulvene: Cationic Polymerization of Enediynes

Enediyne compounds have found limited applications in polymer science and material chemistry due to the poor regioselectivity and/or the step-growth nature in their radical polymerizations. However, the cationic cyclization of enediynes exhibits a high regioselective 5-exo-dig mechanism, providing a new strategy for the synthesis of polyfulvene derivatives. The expected polymers were successfully produced by cationic polymerization of enediynes induced by CF₃SO₃H, and a well-defined conjugated structure was confirmed by NMR, IR, and UV–vis spectroscopy. GPC analysis shows a relatively narrow molecular weight distribution, and the molecular weight reaches up to 62.9 kDa. On the other hand, the structural features of the obtained polymers and the mechanism of the cationic polymerization were investigated through kinetic study and MALDI-TOF MS analysis, which revealed a second-order consumption of enediyne monomer and the polymerization being probably terminated through intramolecular abstraction of proton from the neighboring group

Cobalt-Catalyzed Borylation of Aryl Halides and Pseudohalides

We report the first Co-catalyzed borylation of aryl halides and pseudohalides with bis­(pinacolato)­diboron (B₂pin₂). The synthesis of two new Co­(II) complexes of oxazolinylferrocenylphosphine ligands is described. Upon activation with LiMe, the Co complex catalyzes the borylation reactions of aryl bromides, iodides, sulfonates, arenediazonium salts, and even aryl chlorides under mild conditions, providing the borylated products in excellent to moderate yields and with high functional group tolerance

Organelle-Specific Nitric Oxide Detection in Living Cells via HaloTag Protein Labeling

<div><p>Nitric oxide (NO) is a membrane-permeable signaling molecule that is constantly produced, transferred, and consumed <i>in vivo</i>. NO participates and plays important roles in multiple biological processes. However, spatiotemporal imaging of NO in living cells is challenging. To fill the gap in currently used techniques, we exploited the versatility of HaloTag technology and synthesized a novel organelle-targetable fluorescent probe called HTDAF-2DA. We demonstrate the utility of the probe by monitoring subcellular NO dynamics. The developed strategy enables precise determination of local NO function.</p></div

Properties of NO Sensor HTDAF-2.

<p>(A) Fluorescence spectra of HTDAF-2. Fluorescence excitation and emission spectra of 10 nM HTDAF-2 in PBS (pH 7.4) before (dark red lines) and after (orange lines) the addition of 0.5 mM NO donor (DEA NONOate) at 25°C. Excitation spectrum recorded at an emission wavelength of 525 nm shows a maximum at 488 nm. Emission spectrum recorded at an excitation wavelength of 480 nm shows a maximum at 512 nm. (B) The fluorescence intensities of HTDAF-2 in the presence of different concentrations of NO donor (DEA NONOate) normalized to the initial value. (C) The fluorescence response of HTDAF-2 after the addition of 2 mM xanthine/20 mU xanthine oxidase, 0.5 mM H₂O₂, NO²⁻, NO³⁻, MAHMA NONOate, and DEA NONOate for 30 min in PBS solution. (D) The fluorescence response of HTDAF-2 to NO donor (DEA NONOate) at the indicated pH. Error bars represent the standard deviation (SD).</p

Fluorescence detection of NO in subcellular organelles of HeLa and MCF-7 cells.

<p>Targeted localization of HTDAF-2 by conjugation to HaloTag proteins in living HeLa cells. Images present HeLa cells expressing HaloTag in the cytosol/nucleus (A), nucleus (B), membrane (C), and mitochondria (D), with the red fluorescent protein mCherry fused with the same signal peptides. Scale bar = 10 μm. (E) Direct in-gel fluorescence of control (1), nucleus-HaloTag (2), plasma membrane-HaloTag (3), cytosol-HaloTag (4), and mitochondria-HaloTag (5) in HeLa cells labeled with 5 μM HTDAF-2DA. (F) The fluorescence responses of 5 μM HTDAF-2DA targeted in the plasma membrane to various concentrations of NO donor (DEA NONOate) in HeLa cells. (G and H) Kinetics of fluorescence response of 5 μM HTDAF-2DA in different subcellular compartments of HeLa (G) and MCF-7 (H) cells upon the addition of NO donor (DEA NONOate). Error bars represent SD.</p

Nanoscale Metal–Organic Frameworks for Ratiometric Oxygen Sensing in Live Cells

We report the design of a phosphorescence/fluorescence dual-emissive nanoscale metal–organic framework (NMOF), R-UiO, as an intracellular oxygen (O₂) sensor. R-UiO contains a Pt­(II)-porphyrin ligand as an O₂-sensitive probe and a Rhodamine-B isothiocyanate ligand as an O₂-insensitive reference probe. It exhibits good crystallinity, high stability, and excellent ratiometric luminescence response to O₂ partial pressure. <i>In vitro</i> experiments confirmed the applicability of R-UiO as an intracellular O₂ biosensor. This work is the first report of a NMOF-based intracellular oxygen sensor and should inspire the design of ratiometric NMOF sensors for other important analytes in biological systems

Structures and reaction chemistry of HTDAF-2DA.

<p>Structures and reaction chemistry of HTDAF-2DA.</p

On-Surface Formation of One-Dimensional Polyphenylene through Bergman Cyclization

On-surface fabrication of covalently interlinked conjugated nanostructures has attracted significant attention, mainly because of the high stability and efficient electron transport ability of these structures. Here, from the interplay of scanning tunneling microscopy imaging and density functional theory calculations, we report for the first time on-surface formation of one-dimensional polyphenylene chains through Bergman cyclization followed by radical polymerization on Cu(110). The formed surface nanostructures were further corroborated by the results for the ex situ-synthesized molecular product after Bergman cyclization. These findings are of particular interest and importance for the construction of molecular electronic nanodevices on surfaces

Measurement of endogenous NO production in activated macrophages by HTDAF-2DA and DAF-2DA.

<p>(A and B) NO detection in Raw 264.7 macrophages expressing HaloTag in the cytosol/nucleus (A) or nucleus (B) stained by HTDAF-2DA. (C) NO detection in Raw 264.7 macrophages stainedby DAF-2DA. For A-C, cells were prestimulated for 8 h with LPS (0.5 μg/ml) and IFN-γ (250 U/ml) with or without L-NAME (2 mM). Data were measured in pooled cells with microplate reader. Error bars represent SD.</p