藻胆蛋白的Langmuir-Blodgett膜——Ⅰ.R-藻红蛋白单分子膜及蛋白构象变化的研究

测定了R-藻红蛋白(R-PE)在气/液界面上的表面压-面积曲线(tt-A等温线),结果表明R-PE具有很好的成膜性能,且由n-A等温线求得的单分子占有面积与R-PE以盘状形态“平躺”于液面上时的分子占有面积相同。R-PELB膜的透射电子显微镜(TEM)图象和椭圆偏振关于R-PE单分子膜厚度的测定,说明R-PE分子在基片上的取向是其盘平面与基片表面平行。根据这些依据,提出了R-PE单分子膜的结构。将R-PE在气/液界面上形成的单分子膜在适当表面压下用LB技术转移到基片上,测得了蛋白累积单分子膜的吸收及荧光光谱,R-PE单分子膜的吸收和荧光光谱与其在水溶液中无显著差别。膜的CD光谱与R-PE水溶液的CD光谱比较说明,当R-PE成膜后其二级结构发生了变化,即蛋白的p-折叠片构象组分增加。     

单分散、小粒径金纳米颗粒的形貌控制增长

利用种子生长法合成了形状规则、尺寸单一的形状不同金纳米颗粒. 其中立方体纳米颗粒的边长为33±2 nm, 它是在十六烷基三甲基溴化胺(CTAB)存在的条件下, 在种子的表面上用弱还原剂——抗坏血酸还原而成的. 在这个体系中, 表面活性剂CTAB既作为保护剂又作为颗粒成长的导向剂. 用UV-vis, TEM, XRD对纳米颗粒的光学性质、几何形状、纳米颗粒的单层膜概貌以及纳米颗粒的晶体结构作了表征. 考察了种子生长的时间、种子的量、抗坏血酸的量对生成纳米颗粒形状的影响.     

Effect of Hydrophobic Chain of Dye Molecule and Surface of Active Crystal on the Organized Assemblies Formation of Dyes

Four derivatives of 5,5',6,6'-tetrachlorobenzimidazolocarbocyanine iodide with different long alkyl chain substituents in N-position of polymethine chromophore have been used for investigating the influence of hydrophobicity of dyes on the aggregation.It has been found that all dyes formed monomeric species in methyl alcohol. However, after addition of water to CH_3OH to change the polarity of the solvent, difference between dyes appeared.Addition of inorganic salt facilitated the J-aggregation of easy soluble dye, but it seems useless for the sparely soluble dye.Platelets cut from AgBr polycrystal or pressed AgBr powder have been used as substrate for adsorbing dyes. After addition of hexanoic acid, eventually the J-aggregate on AgBr surface could be destroyed.Voltammetry is a useful tool to investigate the interaction between dyes and AgBr. Experimental results showed that the longer the carbon chain substituents is, the stronger the interaction between AgBr and dyes would be.     

表面膨胀粘度的测定研究

用不同浓度的NaCl和表面活性剂直链的十二烷基苯磺酸钠(LAS)、稳定剂聚丙烯酰胺和水所组成的泡沫体系为研究对象,通过表面压松弛的方法,利用计算机数据拟合,得到了计算表面膨胀粘度的方法。     

Preparation,stability and two-dimensional ordered arrangement of gold nanoparticles capped by surfactants with different chain lengths

Gold nanoparticles modified with C10NH2, C12NH2, C16NH2 and C18NH2 respectively have been prepared by the reverse micelle method. Nanoparticles stability and their two-dimensional (2D) ordered arrangement were studied by UV-Vis absorption spectra and LB technique. The factors, such as the chain length and the size distribution of particles, which affect the 2D ordered arrangement formation, are discussed. Experimental results show that the longer the chain length of surfactants capping the gold nanoparticles, the more stable the nanoparticles, and the more ordered 2D arrangement of gold nanoparticles.     

CONCENTRATION EFFECT OF SENSITIZING DYE ON SPECTRAL SENSITIZATION OF SILVER HALIDE

The effect of concentration of four dyes has been investigated, which are of similar mo-lecular structures, same spectroscopic absorption spectra, and very close values in redox po-tential upon the spectral sensitization of photographic emulsion. The results have shownthat dyes which are liable to form J-aggregate diminish the effect of dye-induced desensiti-zation, while dyes which are not easy to form J-aggregate exhibit a very strong effect ofdye-induced desensitization. According to phosphorescence and electrochemistry experimentalresults, we could assume that the aggregate state acts in a way to regenerate the oxidizeddye, thus being favorable to the spectral sensitization. In this paper, the factor of inhibi-tion of development by dye adsorption has also been proposed to be a factor which cannotbe neglected in dye-induced desensitization.     

Langmuir-Blodgett films of phycobiliproteins (I)——Monomolecular film and conformational studies of R-phycoerythrin

The surface pressure-area (π-A) isotherm of R-phycoerythrin (R-PE) at the air-water interface has been measured. The results indicate that R-PE can form the monomolecular film. Moreover, the molecule-occupied area extrapolating the linear part of the n-A isotherm is identical with that when an R-PE molecule is located at the interface with its disk plane parallel to the air-water interface. The transmission electron micrograph (TEM) and the measurement of the thickness of the protein monolayer by ellipsometry show that the orientation of R-PE disk plane on the substrate is parallel to the plane of substrate. Absorption and fluorescence spectra of R-PE LB multilayers were obtained through transferring R-PE monolayer at the air-water interface to the substrates at the proper surface pressure by Langmuir-Blodgett (LB) technique. These spectra of R-PE LB films do not show distinct differences from those in aqueous solution. Comparative studies of circular dichroism (CD) spectra of the protein between in aq     

单分散球状纳米金颗粒的合成

综述了近年来单分散球状金纳米颗粒的合成研究进展。分析了球状单分散金纳米颗粒的应用前景,介绍了单分散球状金纳米颗粒的主要合成方法如种子生长、回流熟化、尺寸选择沉淀分级以及电泳法等,评述了各种方法的优缺点。最后提出了单分散球状金纳米颗粒合成的一些问题,并展望了单分散球状金纳米颗粒的研究和发展方向。     

有序纳米金颗粒的多层组装

采用LB技术组装了一种三维有序的由十八胺修饰的纳米金颗粒多层结构.这是一种新的组装纳米颗粒三维有序聚集体的方法.为了扩大这种方法的适用范围,在组装过程中,将有机小分子1 苯基 5 巯基四氮唑引进结构,形成了新的纳米金颗粒多层聚集体.这两种多层膜经透射电子显微镜和小角X射线衍射测量证明构成多层膜的单层膜上的纳米金颗粒是有序的,并且颗粒在层与层之间的排列也是有序的.