电致发光金属配合物和有机小分子的合成与性能

本文以调控发光颜色、提高发光效率为目的，通过改变配体、中心金属离子、取代基等进行颜色调节；通过引入电子或空穴传输单元，实现发光分子的功能化进而改善载流子传输提高发光效率。文中主要以有机小分子和金属配合物为研究对象，它们本身都具有良好的发光性质。工作集中围绕以下几个问题展开：1、PPV齐聚物是一类高效发光的分子体系，如果在其中嵌入8一取代的哇琳单元对发光会有什么影响？2、使用含噁二唑（具有电子传输功能）的配体得到的金属配合物是否能同时拥有双重功能，即高效发光（金属配合物的特点）和优良的电子传输？3、由N2O-双齿配体转变成N，N-双齿配体，配合物的发光又会如何？4、稀土配合物具有高的光致发光效率，但电致发光效率非常低，能否通过咔哇或呛二吟功能化来改善载流子传输，提高电致发光效率？主要工作及取得的结果概述如下：1、经由Knoevenagel缩合反应合成了一系列共骊的2，21-（1，4-芳二乙烯基）双-8-取代喹啉。单晶X-射线衍射研究表明固态下存在分子间，π…π堆积相互作用，这对于载流子传输是比较有利的。喹啉8-位于的取代基的变化对发光影响不大，表明刚性共扼骨架对发光起主要贡献。改变中心的芳核，明显可以调控发光颜色。当存在分子内电荷转移时，与不存在的相比，发光显著红移。电致发光性质表明这些含双喳琳的PPV齐聚物是良好的发光和电子传输材料。2、存在分子内氢键的化合物2-（2-羟基苯基）-5-苯基-1，3，4-噁二唑（HOXD），具有激发态分子内质子转移（ESIPT）特性。在室温下，用365脚的紫外灯照射时表现强的兰色荧光。室温和低温（77K）下的磷光光谱表明它在固态下具有较强的磷光发射，与理论预测完全一致。多层电致发光器件ITO加PB／HOXD／BCP／Alq3／Mg：Ag最大亮度达到656cd／m2，电流效率为0．37cd／A。当把HoxD掺在cBP中时，亮度和效率都有一定程度的提高，达到870cd／m2和0.82cd／A。3、合成了含有德二哩配体（HOXD）的碱金属配合物MOxD（M=Li，Na，K）。我们发现配合物的发光颜色取决于中心金属离子，LiOXD是一个优良的蓝光材料，半峰宽是65nm，发射峰位在478nm，它也可以作为界面材料使用，起到和LIF相同的作用，即改善电子注入。同时作者首次报道了钠和钾的配合物可以用作发光材料。电致发光性质表明这些配合物是优良的蓝／绿色发光和电子注入／传输材料。4、使用从N双齿配体代替N，O-双齿配体（比如8-羟基喹啉），合成了含有2－（2-羟基喹啉）苯并咪唑的锌、铍和硼配合物。用硼配合物作为发光层的三层器件ITO/NPB/boron-complex／Alq3／LiF／A1所得到的光谱覆盖了从400到750nm的区域，表明获得了一个很好的白色发光。白光分别源于激子和激基复合物发光，由三种成分构成：来自于硼配合物的兰色发光（490nm）；来自于Alq3的发光（535nln）；NPB和BPh2（Pybm）界面形成的激基复合物发光（610nm）。器件最大亮度是110cd／m2最大效率是0.8cd／A。5、设计、合成了咔唑、噁二唑功能化的稀土馆配合物，期望通过改善空穴和电子传输来提高发光效率。含咔哇的配合物的双层器件发光光谱较宽，包括三价铺的特征发射和一个宽峰，可能是咔唑的发光。当使用TPD做空穴传输层时，噁二唑铺配合物的电致发光器件得到纯正明亮的红色发光，器件结构为ITO／TPD（40nm）／（OXD-PyBM）Eu（DBM）3（SOnm）／LiF（Inm）／Al（200m），启动电压为7.8V，在21v时达到最大亮度322cd／m2。亮度为57cd／m2和13．sv时电流效率最大，为1.9cd／A，对应外量子效率是1.7％。高的效率表明通过引入噁二唑基团，配合物的电子传输能力得到明显改善。6、初步研究了三线态发光的铱的金属有机配合物，得到了高亮度、高效率的绿色发光；对8-羟基喹啉锌配合物的高分子化也做了初步探讨。

碱性成纤维细胞生长因子的克隆、表达、纯化、生物活性及与小分子的相互作用

人碱性成纤维细胞生长因子（bFGF）是一种单链的具有与肝素结合能力的多肤分子，它能够调节内皮细胞及其它来源于中胚层和神经外胚层等多种细胞的生长、分化、迁移和凋亡，同时是一种重要的血管生成因子，因此具有广泛的临床应用价值。本论文就将具有多种生物学功能的碱性碱纤维细胞生长因子开发为基因工程药物所存在的一些基本问题，进行了大量细致的研究工作并获得一些具有新意的研究结果。应用现代基因工程技术分别在原核E.coli系统和真核Pichia pastoris系统件1克隆表达了人碱性碱纤维细胞生长因子，生物活性测定结果表明在毕赤酵母体系中表达的重组人碱性碱纤维细胞生长因子的活性高于E.coli中表达的bFGF的活性。筛选出高分泌型的Pichia pastoris工程菌，并建立了高效表达的方法；经过一步亲和层析既获得了电泳纯的bFGF其产量为100mg／L发酵液。SDS-PAGE电泳以及Western blOt实验都证明了其具有天然bFGF的性质，并用紫外、荧光光谱刘于毕赤酵母表达体系表达的重组人bFGF的三维结构进行了表征，用圆二色谱对其二级结构进行了表征，同时用质谱测定了其精确分子量为17931 Da．首次研究了不同价态的稀土离子与碱性碱纤维细胞生长因子相互作用引起bFGF不同的构象及活性变化，以及聚金属氧酸盐（POM）在低浓度能够刺激bFGF的活性，在高浓度抑制bFGF活性的现象。

毛蕊异黄酮类似物的合成及其对JAK/STAT信号途径调控的构效关系研究

干扰素（IFNs）是最早发现的具有广泛用途的一类细胞因子，IFN-α通过JAK/STAT信号途径调控机体一系列生理和病理反应。至今尚未发现类干扰素的小分子。我们前期研究发现天然产物毛蕊异黄酮可激活干扰素诱导的JAK/STAT信号途径。为发现类干扰素小分子、获得小分子探针，本课题拟建立成熟的JAK/STAT信号途径的筛选模型，合成毛蕊异黄酮及其类似物，研究这些化合物的构效关系，进而尝试通过共价键标记生物素或香豆素来直接研究它们与相关受体的作用。 从异香草醛出发经7步合成反应得到了毛蕊异黄酮。采用平行合成策略得到异黄酮类化合物；采用分支式合成策略，以取代苯乙酸作为合成砌块，获得具有与异黄酮类似结构的香豆素、3-芳基喹诺酮。与分离得到的黄酮类化合物，构建了一个包括异黄酮、黄酮、香豆素、3-芳基喹诺酮在内的化合物库。 建立了包含IFN-α刺激反应元件 (ISRE)的荧光素酶报告基因体系，通过筛选化合物库中的化合物，发现异黄酮骨架为激活JAK/STAT信号途径必须结构、毛蕊异黄酮7-位酚羟基被取代后活性丧失。根据以上结果，对毛蕊异黄酮3′-位标记物的合成进行了初步尝试。 发现山茱萸科植物青荚叶(Helwingia japonica (Thunb.) Dietr.)有抑制蛋白酪氨酸磷酸酯酶1B（PTP1B）的活性。从其地上部分95%乙醇提取物的乙酸乙酯部分分离得到5个化合物,应用波谱方法及与已知品对照的手段鉴定它们为p-menth-2-en-1β, 4β, 8-triol (Z-1)、blumenol A (Z-2)、2′,3′,4′,5′,6′-五羟基查尔酮(Z-3)、洋芹素7-O-β-D-吡喃葡萄糖苷(Z-4)、木犀草素7-O-β-D-吡喃葡萄糖苷(Z-5). Interferons (IFNs) are one kind of cytokines with broad functions. IFN-α mediates series physiological and pathological changes of human body via JAK/STAT pathway. Untill now, no IFNs-like small molecules are discovered. In our preliminary experiment, the natural product calycosin has been observed to activate JAK/STAT pathway. Therefore, we establish a luciferase reporter gene system and synthesize calycosin and its analogues to reveal their structure-activity relationship (SAR). Besides, in order to prove that calycosin activates JAK/STAT pathway through IFN receptor, we attempted to tag it with biotin or coumarin by covalent bonding. Calycosin was synthesized from isovanillin via seven steps. Other isoflavones were obtained by parallel synthesis; coumarins and quinolones were prepared through divergent synthesis, using substituted phenylacetic acids as building blocks. Combing with natural flavones, a small molecule library was established. A luciferase reporter gene system, consisting of 5 copies of the ISRE (interferon-stimulated response element), was used for screening of small molecules from that library. We found that the core-structure of isoflavone was necessary, and if the 7-OH is substituted, the activity slumps. According to our observation, we tried to tag biotin or coumarin at 3′-OH of calycosin. The 95% ethanol extract of the aerial parts of Helwingia japonica (Thunb.) Dietr. showed protein tyrosine phosphatase 1B (PTP1B) inhibitory activity. Five compounds were isolated. On the basis of spectral data or by comparison with authentic samples, they were identified as p-menth-2-en-1β,4β,8-triol (1), blumenol A (2), 2′,3′,4′,5′,6′-pentahydroxychalcone (3), apigenin 7-O-β-D-glucopyranoside (4), and luteolin 7-O-β-D-glucopyranoside (5).

Activated carbons chemically modified by concentrated H2SO4 for the adsorption of the pollutants from wastewater and the dibenzothiophene from fuel oils

The surface properties, porosities, and adsorption capacities of activated carbons (AC) are modified by the oxidation treatment using concentrated H2SO4 at temperatures 150-270 degreesC. The modified AC was characterized by N-2 adsorption, base titration, FTIR, and the adsorption of iodine, chlorophenol, methylene blue, and dibenzothiophene. The treatment of AC with concentrated H2SO4 at 250 degreesC greatly increases the mesoporous volume from 0.243 mL/g to 0.452 mL/g, specific surface areas from 393 m(2)/g to 745 m(2)/g, and acidic surface oxygen complexes from 0.071 meq/g to 1.986 meq/g as compared with the unmodified AC. The base titration results indicate that the amount of acidic surface oxygen groups on the modified AC increases with increasing the treatment temperatures and carboxyls and phenols are the most abundant carbon-oxygen functional groups. The carboxyl groups, COO- species, and hydroxyl groups are detected mainly for the sample treated at 250 degreesC. The mesoporous properties of the AC modified by concentrated H2SO4 were further tested by the adsorption of methylene blue and dibenzothiophene. The AC modified by concentrated H2SO4 at 250 degreesC has much higher adsorption capacities for large molecules (e.g., methylene blue and dibenzothiophene) than the unmodified AC but less adsorption capacities for small molecules (e.g., iodine). The adsorption results from aqueous solutions have been interpreted using Freundlich adsorption models.

Matrix-assisted laser desorption/ionization mass spectrometry using porous silicon and silica gel as matrix

Porous silicon powder and silica gel particles have been applied as inorganic matrices for the analysis of small molecules in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOFMS). In contrast to conventional MALDI-TOFMS, the signal interference of low-molecular analytes by the matrix has been eliminated. Almost no fragmentations of the analytes were observed. Effects of various factors, such as the particle and pore size, the suspending solution, and sample preparation procedures, on the intensity of mass spectra have been investigated. The pore structure of the inorganic matrix and penetration of the analytes into the pores must be optimized for effective desorption and ionization of the analytes. Matrices (DHB and HCCA) were covalently bound to silica gel for improvement of spectrum intensity. Copyright (C) 2001 John Wiley & Sons, Ltd.

Amplified electrochemical aptasensor taking AuNPs based sandwich sensing platform as a model

Here, we report a sensitive amplified electrochemical impedimetric aptasensor for thrombin, a kind of serine protease that plays important role in thrombosis and haemostasis. For improving detection sensitivity, a sandwich sensing platform is fabricated, in which the thiolated aptamers are firstly immobilized on a gold substrate to capture the thrombin molecules, and then the aptamer functionalized Au nanoparticles (AuNPs) are used to amplify the impedimetric signals.

Electrochemical surface plasmon resonance detection of enzymatic reaction in bilayer lipid

In this paper, electrochemical surface plasmon resonance (SPR) method was first used to detect enzymatic reaction in bilayer lipid membrane (BLM) based on immobilizing horseradish peroxidase (HRP) in the BLMs supported by the redox polyaniline (PAn) film. By SPR kinetic curve in situ monitoring the redox transformation of PAn film resulted from the reaction between HRP and PAn, the enzymatic reaction of HRP with H2O2, was successfully analyzed by electrochemical SPR spectroscopy.

Multifunctional label-free electrochemical biosensor based on an integrated aptamer

Aptamers, which are in vitro selected functional oligonucleotides, have been employed to design novel biosensors (i.e., aptasensors) due to their inherent selectivity, affinity, and their multifarious advantages over traditional recognition elements. In this work, we reported a multifunctional reusable label-free electrochemical biosensor based on an integrated aptamer for parallel detection of adenosine triphosphate (ATP) and alpha-thrombin, by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A An electrode as the sensing surface was modified with a part DNA duplex which contained a 5'-thiolated partly complementary strand (PCS) and a mixed aptamer (MBA).

Self-assembly of single-stranded RNA on carbon nanotube: Polyadenylic acid to form a duplex structure

All messenger-RNA (mRNA) molecules in eukaryotic cells have a polyadenylic acid [poly (rA)] tail at the 3'-end and human poly (rA) polymerase (PAP) has been considered as a tumor-specific target. A ligand that is capable of recognizing and binding to the poly(M) tail of mRNA might interfere with the full processing of mRNA by PAP and can be a potential therapeutic agent. We report here for the first time that single-walled carbon nanotubes (SWNTs) can cause single-stranded poly (M) to self-structure and form a duplex structure, which is studied by UV melting, atomic force microscopy, circular dichroism spectroscopy, and NMR spectrometry.

Methylene blue as an indicator for sensitive electrochemical detection of adenosine based on aptamer switch

In this paper, a simple, label-free and regenerative method was proposed to study the interaction between aptamer and small molecule by using methylene blue (MB+) as an electrochemical indicator. A thiolated capture probe containing twelve bases was firstly self-assembled on gold electrode by gold-sulfur affinity. Aptamer probe containing thirty two bases, which was designed to hybridize with capture DNA sequence and specifically recognize adenosine, was then immobilized on the electrode surface by hybridization reaction. MB+ was abundantly adsorbed on the aptamer probe by the specific interaction between MB+ and guanine base in aptamer probe. MB+-anchored aptamer probe can be forced to dissociate from the sensing interface after adenosine triggered structure switching of the aptamer. The peak current of MB+ linearly decreased with the concentration of adenosine over a range of 2 x 10 (8)- x 10 (6) M with a detection limit of 1 x 10 (8) M. In addition, we examined the selectivity of this electrochemical biosensor for cytidine, uridine and guanosine that belonged to the nucleosides family and possessed 1 similar structure with adenosine.

[Ru(bpy)(2)(dcbpy)NHS] Labeling/Aptamer-Based Biosensor for the Detection of Lysozyme by Increasing Sensitivity with Gold Nanoparticle Amplification

A novel [Ru(bpy)(2) (dcbpy)NHS] labeling/aptamer-based biosensor combined with gold nanoparticle amplification for the determination of lysozyme with an electrochemiluminescence (ECL) method is presented. In this work, an aptamer, an ECL probe, gold nanoparticle amplification, and competition assay are the main protocols employed in ECL detection. With all the protocols used, an original biosensor coupled with an aptamer and [Ru(bpy)(2)(dcbpy)NHS] has been prepared. Its high selectivity and sensitivity are the main advantages over other traditional [Ru(bpy)(3)](2+) biosensors. The electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) characterization illustrate that this biosensor is fabricated successfully. Finally, the biosensor was applied to a displacement assay in different concentrations of lysozyme solution, and an ultrasensitive ECL signal was obtained. The ECL intensity decreased proportionally to the lysozyme concentration over the range 1.0 x 10-(13)-1.0 x 10(-8) mol L-1 with a detection limit of 1.0 x 10(-13) mol L-1.

Quantifying intrinsic specificity: A potential complement to affinity in drug screening

We report here the investigation of a novel description of specificity in protein-ligand binding based on energy landscape theory. We define a new term, intrinsic specificity ratio (ISR), which describes the level of discrimination in binding free energies of the native basin for a protein-ligand complex from the weaker binding states of the same ligand. We discuss the relationship between the intrinsic specificity we defined here and the conventional definition of specificity. In a docking study of molecules with the enzyme COX-2, we demonstrate a statistical correspondence between ISR value and geometrical shapes of the small molecules binding to COX-2. We further observe that the known selective (nonselective) inhibitors of COX-2 have higher (lower) ISR values. We suggest that intrinsic specificity ratio may be a useful new criterion and a complement to affinity in drug screening and in searching for potential drug lead compounds.

Construction of metal nanoparticle/multiwalled carbon nanotube hybrid nanostructures providing the most accessible reaction sites

Functionalized multiwalled carbon nanotubes (MWNTs) were selected as cross-linkers to construct three-dimensional (3D) porous nanoparticle/MWNT hybrid nanostructures by "bottom-up'' self-assembly. The resultant 3D hybrid nanostructure was different from that of metal nanoparticle multilayer assemblies prepared by traditional routes using small molecules or polymers as cross-linkers. The rigidity of the MWNTs resulted in only partial coverage of the nanoparticle surfaces between the linkers during the growth of multilayer film, providing more accessible surfaces to allow target molecules to adsorb on to and react with. HRP was used as a simple model to study the porosity of this assembly.

Assembly process of CuHCF/MPA multilayers on gold nanoparticles modified electrode and characterization by electrochemical SPR

Gold nanoparticles were deposited onto 2-mercaptoethylamine (MEA)-assembled planar gold thin film to construct gold nanoparticles modified electrode by virtue of a solution-based self-assembly strategy. Subsequently, 3-mercaptopropionic acid (MPA)-bridged copper hexacyanoferrate (CuHCF) multilayers were constructed on the as-prepared gold nanoparticles modified electrode. The resulted multilayer nanostructures were investigated by electrochemical surface plasmon resonance (EC-SPR) and atomic force microscopy (AFM) with primary emphasis upon the effect of the gold nanoparticles on the MPA/CuHCF multilayers growth and their surface morphology. Compared with the multilayer system on a planar gold electrode, the different electrochemical and optical properties might result from higher curvature effect and extraordinary surface-to-volume ratio characteristic of gold nanoparticles and the nanoparticle-selective growth of CuHCF. A dendrimer-like assembly process was proposed to explain the experiment results. This new motif of multilayer on the gold nanoparticles modified electrode was different from that of on a planar gold electrode, indicating a potential application of EC-SPR technique in the study of nanocomposite materials.