具有抗菌性能的载药复合微纳米纤维的制备及其结构和性能表征

利用静电纺丝技术制备了一种具有抗菌性能的氧化锌(ZnO)/聚乳酸(PLA)/聚己内酯(PCL)载药微纳米纤维膜,并通过扫描电子显微镜(SEM)、X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)分别对复合膜的表面形态、元素组成和化学结构进行表征。通过抗菌实验评价了复合膜的抗菌性能,用紫外分光光度计测试复合膜在体外的药物释放行为。结果显示,以物理共混的方式将ZnO和氢溴酸高乌甲素(LAH)成功载入复合微纳米纤维;与PLA/PCL复合微纳米纤维膜相比,ZnO/PLA/PCL复合微纳米纤维膜表现出更好的抗菌效率。当ZnO含量为10%(wt)时,复合微纳米纤维膜具有最佳的抗菌性能;药物释放性能结果表明,ZnO/PLA/PCL复合微纳米纤维膜具有良好的药物缓释性能。     

N-萘甲基多乙撑多胺类荧光化学敏感器

荧光化学敏感器（ＦｌｕｏｒｅｓｃｅｎｃｅＣｈｅｍｉｃａｌＳｅｎｓｏｒ,ＦＣＳ）是近年来得到迅速发展用以检测外来物种的一种新方法．一般说来,它由下列三个部分所组成：（１）外来物种的接受体部分,（２）荧光发射部分,（３）连接体部分．作为接受体部分的设计是决定ＦＣＳ在检测物种时的选择性或专一性的关键所在．因此其设计往往要和拟检测物种的结构特征相联系．荧光发射部分的选定则和ＦＣＳ的灵敏度相关,适当的选择会使ＦＣＳ的接受体在接受外来物种后,能灵敏地引起荧光发射强度或特征发射波长的变化,使人们可敏锐地发觉所…     

基于氧化锌/碳纳米纤维材料的氧氟沙星电化学传感器的构建及应用

通过静电纺丝技术合成碳纳米纤维,以循环伏安法在此碳纤维上电聚合乙酸锌制备复合纳米材料作为一种新型的电化学增敏剂,用于修饰玻碳电极,开发了一种基于碳纤维和氧化锌复合材料的新型电化学传感器(ZnO/CNF/GCE)。使用循环伏安法、差分脉冲伏安法等进行电化学催化性能的研究,并优化实验条件。结果表明,与裸电极相比,在pH 5.5磷酸盐缓冲溶液中,ZnO/CNF/GCE修饰电极能使氧氟沙星的峰电流明显提升,线性范围1~200μmol/L,检测限为0.33μmol/L。该ZnO/CNF/GCE修饰电极已用于氧氟沙星滴耳液中氧氟沙星的含量测定。     

Immobilizing a Fluorescent Dye Offers Potential to Investigate the Glass/Resin Interface

Silane coupling agents are commonly applied to glass fibers to promote fiber/resin adhesion and enhance durability in composite parts. In this study, a coupling agent multilayer on glass was doped with trace levels of the dimethylaminonitrostilbene (DMANS) fluorophore. The fluorophore was immobilized on the glass surface by tethering the molecule to a triethoxy silane coupling agent, creating the DMANS/silane coupling agent molecule (DMSCA). DMSCA was then diluted with commonly used coupling agents and grafted to a glass microscope coverslip to create a model composite interface. A 53-nm blue shift in fluorescence from the immobilized DMSCA can be followed during cure of an epoxy resin overlayer, giving this technique potential to monitor the properties of the fiber/resin interface during composite processing. Contact angle measurements on these coupling agent layers were similar in the presence or absence of the DMSCA molecule, suggesting that trace levels of the fluorescent probe did not affect the structure of the layer. The immobilized DMSCA molecule behaved similarly to the DMANS precursor in solution. Both showed longer wavelength fluorescence in more polar environments. Copyright 2000 Academic Press.     

酞菁化合物光敏化氧化-还原反应的研究——Ⅲ.在胶束体系中光敏化还原甲基紫精的研究

本文报道我们合成的几种锌酞菁衍生物在胶束体系中,在电子给体EDTA的存在下,光敏化还原甲基紫精(MV²⁺)的研究.结果表明,锌酞菁及其衍生物在阳离子表面活性剂的胶束体系中,其敏化效果比在中性或阴离子表面活性剂的胶束体系中更为有效.结构不同的锌酞菁衍生物的敏化效果亦有显著的差异,其中锌酞菁磺酰丁胺敏化效果最好,锌酞菁羧酸次之.用它们作敏化剂时,MV²⁺形成的量子产率一般高达0.4—0.7,比没有取代基的锌酞菁的敏化效果高.     

2-(2-苯并咪唑)-6-甲基吡啶锌配合物的合成及发光性质

合成了2-(2-苯并咪唑)-6-甲基吡啶及其锌配合物,通过元素分析、摩尔电导率、红外光谱和紫外光谱对产物进行了表征,并运用荧光光谱对配合物的发光性质进行了研究。结果表明,锌配合物在DMF溶液中的荧光最大发射波长为428nm,在固态下的荧光最大发射波长为448nm,均属于蓝光发射,具有作为蓝色发光材料的潜能。     

Synthesis,electrochemistry, and <Emphasis Type="BoldItalic">in situ</Emphasis> spectroelectrochemistry of a new water-soluble zinc phthalocyanine substituted with naphthoxy-4-sulfonic acid sodium salt

A new water-soluble zinc phthalocyanine, 2,9,16,23-tetrakis[4-(1-naphthoxy-4-sulfonic acid sodium salt)] phthalocyaninato zinc NhtZnPc, where Nht indicates the naphthoxy-4-sulfonic acid sodium salt, was synthesized and its electrochemical and spectroelectrochemical properties were investigated in DMSO solution. The formation of NhtZnPc was monitored with the UV–vis spectral changes of NhtH₂Pc in MeOH solution. The electrochemical studies showed that NhtZnPc displayed two reduction waves assigned to Pc(3−)/Pc(2−) and Pc(4−)/Pc(3−) couples, while it also showed one oxidation wave which was assigned to Pc(−)/Pc(2−) couples. The half-wave potential of the first reduction is shifted by 0.067 V compared to that of unsubstituted metal-free phthalocyanine (H₂Pc). This result shows that the weak electron-withdrawing sulfonated-naphthoxy groups on macrocyle core make the reduction processes of NhtZnPc easier in DMSO solution. The spectroelectrochemical results showed that the first reduction product exhibited the characteristic spectral changes corresponding to mono-anionic species of zinc phthalocyanine having long-term stability during the reduction process. But, the second reduction product resulted in unstable di-anionic forms in DMSO.     

Effects of substituents on synthetic analogs of chlorophylls. Part 1: Synthesis, vibrational properties and excited-state decay characteristics

Understanding the effects of substituents on the spectra of chlorins is essential for a wide variety of applications. Recent developments in synthetic methodology have made possible systematic studies of the properties of the chlorin macrocycle as a function of diverse types and patterns of substituents. In this paper, the spectral, vibrational and excited-state decay characteristics are examined for a set of synthetic chlorins. The chlorins bear substituents at the 5,10,15 (meso) positions or the 3,13 (beta) positions (plus 10-mesityl in a series of compounds) and include 24 zinc chlorins, 18 free base (Fb) analogs and one Fb or zinc oxophorbine. The oxophorbine contains the keto-bearing isocyclic ring present in the natural photosynthetic pigments (e.g. chlorophyll a). The substituents cause no significant perturbation to the structure of the chlorin macrocycle, as evidenced by the vibrational properties investigated using resonance Raman spectroscopy. In contrast, the fluorescence properties are significantly altered due to the electronic effects of substituents. For example, the fluorescence wavelength maximum, quantum yield and lifetime for a zinc chlorin bearing 3,13-diacetyl and 10-mesityl groups (662 nm, 0.28, 6.0 ns) differ substantially from those of the parent unsubstituted chlorin (602 nm, 0.062, 1.7 ns). Each of these properties of the lowest singlet excited state can be progressively stepped between these two extremes by incorporating different substituents. These perturbations are associated with significant changes in the rate constants of the decay pathways of the lowest excited singlet state. In this regard, the zinc chlorins with the red-most fluorescence also have the greatest radiative decay rate constant and are expected to have the fastest nonradiative internal conversion to the ground state. Nonetheless, these complexes have the longest singlet excited-state lifetime. The Fb chlorins bearing the same substituents exhibit similar fluorescence properties. Such combinations of factors render the chlorins suitable for a range of applications that require tunable coverage of the solar spectrum, long-lived excited states and red-region fluorescence.     

Controlled production of ZnO nanoparticles from zinc glycerolate in a sol-gel silica matrix

The controlled production of ZnO nanoparticles within an amorphous silica matrix is achieved using a new methodology consisting of four stages. First, precursor zinc glycerolate nanoparticles are produced within reversed micelles of glycerol in heptane stabilized by the surfactant Aerosol-OT (bis-ethylhexyl sodium sulfosuccinate, AOT). The surface of these nanoparticles is then modified by exchanging AOT with bis-trimethoxysilyl-ethane (BTME). The surface-modified nanoparticles are copolymerized with tetramethoxysilane (TMOS) to provide a composite silica material, in which the nanoparticles are apparently dissolved, producing a uniform distribution of zinc in the silica matrix. Finally, the conversion of zinc to ZnO is achieved by heating the material at 700 degrees C, leading to a uniform dispersion of very small (<10 nm) ZnO particles within the amorphous matrix. The fluorescence spectrum of the ZnO particles within the matrix is blue-shifted, as expected from the strong quantum confinement achieved. The properties of the system at all stages in this synthetic process are monitored using TEM, XRD, fluorescence and FT-IR spectroscopy. Glycerol forms complexes with many metal ions, so the present procedure may be generalized to provide uniform distributions of metal ions and subsequently metal oxide nanoparticles in amorphous silica.     

Luminescence of metal complexes of chelate-substituted tetraphenylporphyrin

The luminescence and absorption spectra of some metal complexes of new tetraphenylporphyrin derivatives containing a chelating group with a heavy atom in the ligand structure were studied and compared with the properties of the zinc complex of unsubstituted tetraphenylporphyrin. The quantum yields of fluorescence and phosphorescence of liquid and frozen solutions of these compounds were measured. The life-times of delayed emission have been estimated, and the nature of bands in the absorption and luminescence spectra of the complexes and their relation with the structure are discussed.     

Aligned electrospun cellulose fibers reinforced epoxy resin composite films with high visible light transmittance

Uniaxially oriented cellulose nanofibers were fabricated by electrospinning on a rotating cylinder collector. The fiber angular standard deviation (a parameter of fiber orientation) of the mats was varied from 65.6 to 26.2^o by adjusting the rotational speed of the collector. Optically transparent epoxy resin composite films reinforced with the electrospun cellulose nanofibrous mats were then prepared by the solution impregnation method. The fiber content in the composite films was in the range of 5–30 wt%. Scanning electron microscopy studies showed that epoxy resin infiltrated and completely filled the pores in the mats. Indistinct epoxy/fiber interfaces, epoxy beads adhering on the fiber surfaces, and torn fiber remnants were found on the fractured composite film surfaces, indicating that the epoxy resin and cellulose fibers formed good interfacial adherence through hydrogen-bonding interaction. In the visible light range, the light transmittance was 88–92% for composite films with fiber loadings of 16–32 wt%. Compared to the composite films reinforced with 20 wt% randomly oriented fibers, the mechanical strength and Young’s modulus of the composite films reinforced with same amount of aligned fibers increased by 71 and 61%, respectively. Dynamical mechanical analysis showed that the storage moduli of the composite films were greatly reinforced in the temperature above the glass transition temperature of the epoxy resin matrix.     

碱性水溶液中BR-M~(2+)(Zn~(2+),Cu~(2+))体系的光谱性质研究

在室温下的NaOH水溶液中Zn2 + 和Cu2 + 对胆红素 (BR)的荧光性质有显著的影响作用 .前者表现出荧光增强作用 ;后者表现出荧光猝灭作用 .本文进一步探讨了BR与Zn2 + 、Cu2 + 混合液的荧光和紫外可见光谱性质 .结果显示 ,当溶液中维持足够的Zn2 + 浓度时 ,Cu2 + 的荧光猝灭作用可受到有效抑制 ;在BR -Zn -Cu体系中Zn2 +优先于Cu2 + 与BR作用     

Compact fluorescence detection using in-fiber microchannels-its potential for lab-on-a-chip applications

This paper reports a compact and practical fluorescence sensor using an in-fiber microchannel. A blue LED, a multimode PMMA or silica fiber and a mini-PMT were used as an excitation source, a light guide and a fluorescence detector, respectively. Microfluidic channels of 100 microm width and 210 microm depth were fabricated in the optical fibers using a direct-write CO(2) laser system. The experimental results show that the sensor has high sensitivity, able to detect 0.005 microg L(-1) of fluorescein in the PBS solution, and the results are reproducible. The results also show that the silica fiber sensor has better sensitivity than that of the PMMA fiber sensor. This could be due to the fouling effect of the frosty layer formed at the microchannel made within the PMMA fiber. It is believed that this fiber sensor has the potential to be integrated into microfluidic chips for lab-on-a-chip applications.     

Quinoxaline-bridged porphyrinoids

Quinoxaline-bridged porphyrinoids (3), the first macrocycles containing dipyrrolylquinoxaline (DPQ, 1) subunits, were synthesized from the condensation of the diformyl-substituted DPQ derivatives (2) and 1,8-diaminoanthracene. The resulting structures were confirmed by X-ray analyses, which showed encapsulation of CHCl(3) molecules within the columnar channels established by the stacked arrangement of the individual macrocycles. The solution phase interactions with fluoride and dihydrogenphosphate anions were studied in the case of the unsubstituted system 3a in CH(2)Cl(2). The binding affinities for these anions, studied at the tetrabutylammonium salts, were found to be enhanced relative to those of the simple, unsubstituted monomeric DPQ "parent" system (1a), presumably as the result of the combined effects of preorganization and cooperative binding permitted by the pyrrole NH donor groups. Positive homotropic allosteric anion binding was observed and is ascribed to the structurally coupled nature of the two binding cavities present in the macrocycles. Support for this latter contention came from energy minimization studies.     

溶液沉淀法制备ZnS-氟碳聚合物电纺纤维光催化复合材料

利用含有羧基的氟碳聚合物电纺纤维为载体和模板材料,常温溶液条件下利用均匀沉淀法,在纤维表面负载硫化锌纳米粒子。通过控制反应条件,得到氟碳聚合物电纺纤维表面均匀分布、无团聚的直径在十几纳米左右的硫化锌-氟碳聚合物电纺纤维光催化复合材料。光催化复合材料的高比表面积和水中有机物富集能力使其在紫外光辐照条件下对次甲基蓝降解效率明显高于ZnS粉体。重复降解实验显示复合材料具有较好的稳定性和重复光催化能力。     

CdTe@TiO2复合纳米微粒的制备与表征

利用溶胶-凝胶法合成了CdTe@TiO2复合纳米微粒. 采用扫描和透射电镜对复合微粒的形貌和结构进行了表征, 并探讨了其形成机理. 通过对复合微粒的光谱性质研究发现, 与TiO2复合后, CdTe纳米微粒的荧光有减弱的趋势, 但却具有相似的荧光寿命, 其荧光寿命都短于原CdTe纳米微粒水溶液中的荧光寿命, 说明该材料作为新一代太阳能电池具有非常大的潜力.     

壳聚糖衍生物处理碳纳米管改性聚丙烯腈基碳纤维

自制了邻苯二甲酰化壳聚糖、萘甲酰化壳聚糖、羧甲基化壳聚糖等3种壳聚糖衍生物对多壁碳纳米管(MWNTs)进行表面处理,发现邻苯二甲酰化壳聚糖(PhthCS)能有效提高MWNTs在极性6～10范围溶剂中的分散性及稳定性,并考察了PhthCS的分子量及浓度对MWNTs的分散性及稳定性的影响;通过微观形貌和元素分析,发现MWN...     

水相锌二次电池正极材料V2O5/C的电化学性能研究

采用溶胶－凝胶法合成了一种V₂O₅/C复合材料.扫描电镜（SEM）和红外光谱（FTIR）分析表明,这是一种外层V₂O₅胶体包覆内层乙炔分子的多孔复合材料.以V₂O₅/C作正极,锌片为负极,Zn(ClO₄)₂溶液为电解质组成水相锌二次电池,采用循环伏安（CV）和电化学阻抗谱（EIS）等方法研究发现:V₂O₅:C质量比为1:1时电极具有最好的电化学性能,电池开路电压达1.64 V; Zn^2＋能分别在1.01 V和1.26 V处分步嵌入V₂O₅/C结构中A、B两种位置,其嵌入电流密度峰值最高可达70 mA•g^－1,并且具有较好的循环充放电性能;在一定放电深度下,V₂O₅/C电极反应速率受Zn^2＋的扩散过程控制.     

荧光光谱法研究纳米硫化锌与牛血清白蛋白的相互作用

采用水相法合成了ZnS纳米颗粒,通过XRD及TEM技术对纳米ZnS进行了表征,结果表明纳米ZnS的粒径约为7～8 nm.利用荧光光谱考察了纳米ZnS与牛血清白蛋白(BSA)的相互作用,结果显示,两者的相互作用可导致BSA内源荧光猝灭,推测其猝灭机理为静态猝灭,结合常数Ka=1.73×105 L·mol-1,结合位点数n...     

XAFS analysis of coprecipitation of zinc by sulfide ions in an acidic solution

The fluorescence XAFS (X–ray absorption fine structure) technique using synchrotron radiation was applied to characterize zinc in the Hg–Zn, Cd–Zn, and Bi–Zn coprecipitates, and to elucidate the reaction mechanism of the coprecipitation of zinc from a strong acidic solution. Hg L_II–, Cd K–, and Bi L_III–edge XAFS spectra suggested that the respective host materials of the coprecipitates listed above are metacinnabar (HgS), greenockite (CdS), and bismuthinite (Bi₂S₃) and that existence of zinc has not affected the local structure of the host metal sulfides in each system. On the other hand, the Zn K–edge XAFS spectra of each coprecipitate indicated that the chemical forms of zinc compounds are controlled by the crystal structure of the host sulfides.The shapes of the Zn K–XAFS spectra of the Hg–Zn and Cd–Zn coprecipitates showed a strong resemblance to those of crystalline standards ZnS, wurtzite and spharelite. It was suggested that the two coprecipitated phases (HgS, ZnS) and (CdS, ZnS) may form a solid solution in the Hg–Zn and Cd–Zn coprecipitates. The local structure around the zinc(II) ion in the Bi–Zn coprecipitate is the same as that around hexaaqua–zinc(II) ions, and adsorption of soluble ions or mechanical occlusion from the mother liquor is regarded as a driving force of coprecipitation in the Bi–Zn system.