Gold nanoclusters-Cu2+ ensemble-based fluorescence turn-on and real-time assay for acetylcholinesterase activity and inhibitor screening

Based on the specific binding of Cu2+ ions to the 11-mercaptoundecanoic acid (11-MUA)-protected AuNCs with intense orange-red emission, we have proposed and constructed a novel fluorescent nanomaterials-metal ions ensemble at a nonfluorescence off-state. Subsequently, an AuNCs@11-MUA-Cu2+ ensemble-based fluorescent chemosensor, which is amenable to convenient, sensitive, selective, turn-on and real-time assay of acetylcholinesterase (AChE), could be developed by using acetylthiocholine (ATCh) as the substrate. Herein, the sensing ensemble solution exhibits a marvelous fluorescent enhancement in the presence of AChE and ATCh, where AChE hydrolyzes its active substrate ATCh into thiocholine (TCh), and then TCh captures Cu2+ from the ensemble, accompanied by the conversion from fluorescence off-state to on-state of the AuNCs. The AChE activity could be detected less than 0.05 mU/mL within a good linear range from 0.05 to 2.5 mU/mL. Our proposed fluorescence assay can be utilized to evaluate the AChE activity quantitatively in real biological sample, and furthermore to screen the inhibitor of AChE. As far as we know, the present study has reported the first analytical proposal for sensing AChE activity in real time by using a fluorescent nanomaterials-Cu2+ ensemble or focusing on the Cu2+-triggered fluorescence quenching/recovery. This strategy paves a new avenue for exploring the biosensing applications of fluorescent AuNCs, and presents the prospect of AuNCs@11-MUA-Cu2+ ensemble as versatile enzyme activity assay platforms by means of other appropriate substrates/analytes. (C) 2015 Elsevier B.V. All rights reserved

Carbon supported trimetallic nickel-palladium-gold hollow nanoparticles with superior catalytic activity for methanol electrooxidation

In this paper, Ni nanoparticles (NPs) are prepared in an aqueous solution by using sodium borohydride as reducing agent. With Ni NPs as the sacrificial template, hollow NiPdAu NPs are successfully prepared via partly galvanic displacement reaction between suitable metal precursors and Ni NPs. The as-synthesized hollow NiPdAu NPs can well dispersed on the carbon substrate. Transmission electron microscopy, X-ray diffraction and inductively coupled plasma mass spectrometry are taken to analyze the morphology, structure and composition of the as-synthesized catalysts. The prepared catalysts show superior catalytic activity and stability for methanol electrooxidation in alkaline media compared with commercial Pd/C and Pt/C. Catalysts prepared in this work show great potential to be anode catalysts in direct methanol fuel cells. (C) 2015 Elsevier B.V. All rights reserved

Stabilized, Superparamagnetic Functionalized Graphene/Fe3O4@Au Nanocomposites for a Magnetically-Controlled Solid-State Electrochemiluminescence Biosensing Application

Herein, a multifunctional nanoarchitecture has been developed by integrating the branched poly(ethylenimine) functionalized graphene/iron oxide hybrids (BGNs/Fe3O4) and luminol capped gold nanoparticles (luminol-AuNPs). The luminescent luminol-AuNPs as an electrochemiluminescence marker can be assembled on the nanocarrier of BGNs/Fe3O4 hybrids efficiently via the Au-N chemical bonds and electrostatic adsorption. Meanwhile, the multifunctional nanoarchitecture has been proved with excellent electron transfer, good stability, high emission intensity, etc. Furthermore, we successfully developed an ultrasensitive magnetically-controlled solid-state electrochemiluminescence (ECL) platform for label-free determination of HeLa cells using this multifunctional nanocomposite. Excellent performance of the magnetically-controlled ECL biosensing platform has been achieved including a high sensitivity for HeLa cells with a linear range from 20 to 1 x 10 (4) cells/mL, good stability, and reproducibility

Real-time Imaging of Rabies Virus Entry into Living Vero cells

Understanding the mechanism of rabies virus (RABV) infection is vital for prevention and therapy of virulent rabies. However, the infection mechanism remains largely uncharacterized due to the limited methods and viral models. Herein, we utilized a powerful single-virus tracking technique to dynamically and globally visualize the infection process of the live attenuated rabies vaccine strain-SRV9 in living Vero cells. Firstly, it was found that the actin-enriched filopodia is in favor of virus reaching to the cell body. Furthermore, by carrying out drug perturbation experiments, we confirmed that RABV internalization into Vero cells proceeds via classical dynamin-dependent clathrin-mediated endocytosis with requirement for intact actin, but caveolae-dependent endocytosis is not involved. Then, our real-time imaging results unambiguously uncover the characteristics of viral internalization and cellular transport dynamics. In addition, our results directly and quantitatively reveal that the intracellular motility of internalized RABV particles is largely microtubule-dependent. Collectively, our work is crucial for understanding the initial steps of RABV infection, and elucidating the mechanisms of post-infection. Significantly, the results provide profound insight into development of novel and effective antiviral targets

几种稀土微/纳米发光材料的可控合成及其性能研究

微/纳米材料的形貌、尺寸和维度对其物理化学性质有着十分重要的影响，因此制备形貌可控的微/纳米材料、研究晶体的生长机理并探索其应用成为目前化学和材料学领域研究的热点。由于稀土元素独特的4f电子层结构，其化合物在光学、电学、磁学等各个领域都有广泛的应用。基于以上考虑，本文主要利用水热/溶剂热法制备了一系列稀土微/纳米材料，并对其生长机理、光谱特性和载药功能进行了研究。 通过掺杂Ca2+和Sr2+离子制备了常温稳定的六方相GdF3，碱土金属掺杂后引起的晶格膨胀和阴离子缺陷是六方相稳定的主要原因，以Eu3+离子为结构探针研究了正交相向六方相的转变过程。Ba2+离子虽不能引起相转变，但可作为形貌控制剂诱导正交相GdF3从亚微米盘演化为椭球状纳米结构。 在柠檬酸三钠的辅助下合成了磁性-荧光-多孔三功能BaGdF5纳米球。探讨了未掺杂激活离子时样品的发光机理，评价了样品的水溶性、细胞毒性和顺磁性能，并测...The chemical and physical properties of nano-/micromaterials are fundamentally related to their size, shape, and dimensionality, and therefore fabricating morphology-controlled nano-/micromaterials, understanding the crystal growth mechanism, and exploring their application has been the research hotspot in chemistry and material science. Rare earth compounds have been widely used in the fields of optics, electrics, and magnetism due to the unique characteristics resulting from the 4f electrons of rare earth ions. On the basis of above considerations, the dissertation is focused on the controllable synthesis of rare earth nano/micromaterials with hydro/solvthermal method. The growth mechanism, luminescent properties, and drug application in drug delivery have also been investigated. The mai..

溶液法铜基薄膜太阳能电池的制备

铜基半导体材料由于高的光吸收系数以及合适的光学帶隙而被广泛应用于薄膜太阳能电池的吸光层，具有潜在的市场价值。铜基薄膜吸收层材料制备过程主要分为真空法和溶液法。前者需要较高的真空度和昂贵的器械设备，使得器件制备成本下降空间十分有限。溶液法由于操作简单，提供了低成本、大量生产的可能性。在溶液法制备薄膜电池中，纳米晶溶液法和分子前驱体体系两种方法被广泛研究。纳米晶成膜方法涉及复杂的纳米晶合成过程，此外，长碳链的有机配体也对电池性能产生不良的影响。肼溶液法是分子前驱体溶液的代表，也是溶液法最高电池效率的创造者。然而，无水肼本身的易爆炸和剧毒成为阻碍其进一步发展的关键因素。本论文主要针对当前国际上溶液法制备铜基薄膜电池存在的一些问题，致力于发展操作简单，低价低毒的溶液法，并成功地制备了几种常见的铜基薄膜太阳能电池，详细研究如下： 1. 发展了一种简单、低毒的制备CuInS2(CIS)分子前驱体溶液的...Abstract Copper-based semiconductor thin films pose a promising commercial value due to their high light absorption coefficient and suitable optical bandgaps, which have been applied in preparation of photovoltaic device. At present, the deposition methods of copper-based thin films absorbing layer fall into two classes: vacuum-based and solution-based processes. The former requires high vacuum and expensive equipment, which leads to a high manufacturing cost. Solution-based process provides a possibility of low-cost and mass production owing to simple operation. Among the solution-based processes, nanocrystal-based and molecule-based precursor approaches received a great deal of attention. Nanocrystal-deposited thin film absorbing layer needs complex and tedious synthesis, in addition, lo..

新型后过渡金属配合物的合成及催化性能研究

非茂型后过渡金属镍、钯催化剂具有良好的官能团耐受性，尤其是中性催化剂还可以实现单组分催化，这使得它们在烯烃均聚和共聚方面有着很好的应用前景。本论文合成了一系列 (硫)酚-膦(酰)中性镍、钯催化剂，并研究了他们对烯烃均聚和共聚的催化性能。主要内容如下： (1)为了研究[P,O]螯合中性镍催化剂对降冰片烯聚合的催化性能，我们设计合成了一系列酚-膦中性镍催化剂。它们在少量的B(C6F5)3(B/Ni = 3)活化下，可高效催化降冰片烯加成聚合，其中酚氧邻位为叔丁基的催化剂活性可达6.95 × 106 g/molNi?h。同时，这些催化剂还可单组分催化乙烯均聚，其中P上的两个取代基分别为叔丁基和苯基的催化剂活性高达1.07 × 107 g/molNi?h。在降冰片烯与乙烯共聚合实验中，降冰片烯插入率可超过30 mol%。 (2)为了探究酚-膦中性镍催化剂的共聚合性能及耐受性，我们选择了极性降冰片烯...Synthesis and study on Novel Late Transition Metal Catalysts for Olefin Polymerization Yanping Zhang(Polymer Chemistry and Physics) Directed by Professor Yuesheng Li Abstract Non-metallocene late metal (nickel and palladium) catalysts have great tolerance towards polar functional groups, and the neutral ones are even used as single component catalysts, which ensure their good application prospects in olefin (co)polymerization. In this thesis, we have synthesized a series of well-defined phosphine (oxide)-(thio) phenolate neutral nickel and palladium complexes for olefin homo- and copolymerization. The main contents are listed as follow: (1) To study the catalytic behavior of [P,O] chelate nickel catalysts for the vinyl-polymerization of norbornene, a series of phosphine-phenolate neutral n..

Nanoscale {Ln(24)(III)Zn(6)(II)} Triangular Metalloring with Magnetic Refrigerant, Slow Magnetic Relaxation, and Fluorescent Properties

The self-assembly of Ln(ClO4)(3)center dot 6H(2)O and Zn(OAc)(2)center dot 2H(2)O with pyrazine-2-carboxylic acid (HL) results in the formation of three novel nanosized {Ln(24)(III)Zn(6)(II)} triangular metallorings, [Gd24Zn6L24 (OAc)(22)(mu(3)-OH)(30)(H2O)(14)](ClO4)(7)(OAc)center dot 2CH(3)OH center dot 26H(2)O (1), [Tb24Zn6L24(OAc)(22)(mu(3)-OH)(30)(CH3O)(2)(CH3OH)(2)-(H2O)(10)](ClO4)(5)(OH)center dot 6CH(3)OH center dot 12H(2)O (2), and (H3O)[Dy24Zn6L24-(OAc)(22)(mu(3)-OH)(30)(H2O)(14)](ClO4)(7)(OAC)(2)center dot 4CH(3)OH center dot 22H(2)O (3), having the largest nudearity among any known Ln/Zn clusters. Magnetic and luminescent studies reveal the special prowess for each lanthanide complex. Magnetic studies reveal that 1 exhibits a significant cryogenic magnetocaloric effect with a maximum -Delta S-m (isothermal magnetic entropy change) value of 30.0 J kg(-1) K-1 at 2.5 K and 7 T and that a slow magnetization relaxation is observed for the dysprosium analogue. In addition, the solid-state photophysical properties of 2 display strong characteristic Tb-III photoluminescent emission in the visible region, suggesting that Tb-III-based luminescence is sensitized by the effective energy transfer from the ligand HL to the metal centers

A Platinum Highly Concave Cube with one Leg on each Vertex as an Advanced Nanocatalyst for Electrocatalytic Applications

Platinum highly concave cubes with one leg on each vertex (HCCLV) enclosed by {750} facets were conveniently synthesized for the first time through a one-pot solvothermal method in a mixed solvent of oleylamine and isopropanol containing platinum(II) acetylacetonate. This method can also be extended to the synthesis of Pt dendrite nanocubes at shorter reaction times. Preferential overgrowth may facilitate the formation of Pt HCCLV in the presence of oleylamine and isopropanol. The Pt HCCLV exhibit excellent electrocatalytic activity for the oxidation of methanol (7.76x) and ethanol (5.46x) compared to commercial Pt black. Furthermore, the Pt HCCLV show higher stability than Pt dendrite nanocubes and commercial Pt black. The Pt HCCLV also remarkably improve the electrochemiluminescence activity of the luminol/H2O2 system