Catalytic self-assembly preparation and characterization of carbon nitride nano-tubes by a solvothermal method

A solvothermal reaction of anhydrous CaNaCl3 and sodium using cyclohexane as solvent and NiCI2 as catalyst precursor has been carried out to prepare carbon nitride nanotubes successfully at 230℃ and 1.8 MPa. The carbon nitride nanotubes were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), electron energy loss spectrum (EELS) and Raman spectrum.SEM and TEM results indicated that the tubes have a length of 20-30 μm, a uniform outer diameter of about 50-60 nm,an inner diameter of 30-40 nm and are highly ordered assembled as bundles. The EELS measurement indicated that the ratio of N/C was about 1.00. The ED and XRD analyses revealed that the tube may have a new CN crystalline structure. The growth mechanism of nanotubes was discussed.     

Potential control of DNA self-assembly on gold electrode

The self-assembly monolayer (SAM) was prepared with 2-aminoethanethiol (AET) on the gold electrode.A new approach based on potential was first used to control DNA self-assembly covalently onto the SAM with the activation of 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysulfosuccinimide (NHS). The influence of potential on DNA self-assembly was investigated by means of cyclic voltammetry (CV), AC impedance, Auger electron spectrometry (AES) and atomic force microscopy (AFM). The result proves that controlled potential can affect the course of DNA self-assembly. More negative potential can restrain the DNA self-assembly, while more positive potential can accelerate the DNA self-assembly, which is of great significance for the control of DNA self-assembly and will find wide application in the field of DNA-based devices.     

基于氢键的超分子自组装:缔合方式及稳定性

氢键是自然界中最基本的分子间弱相互作用力之一,其强度适中、具有方向性和饱和性,是构建超分子自组装体系的理想推动力.在65篇文献的基础上综述了基于氢键的超分子组装体系的缔合方式及其稳定性影响因素,为设计结构稳定、可自由调控的超分子自组装体系提供理论基础.     

有机非线性材料DAST单晶微片的生长及研究

研发了一种有机非线性光学晶体4-(4-二甲基氨基苯乙烯基)甲基吡啶对甲基苯磺酸盐(DAST)单晶微片的生长方法。首先使用表面支持快速蒸发结晶法制备出了DAST微晶,再通过在甲醇的饱和蒸气压下自组装培养生长成DAST单晶微片。此方法获得的DAST单晶微片不仅厚度均一,而且具有极好的晶体表面质量。另外,还对DAST单晶微片的紫外可见吸收和荧光光谱以及二阶非线性进行了分析和研究。     

配合物LnHL（H4L=N,N′-二（邻-羟基-3-甲氧基苯甲基）草酰胺）的自组装合成过程

3d-4f配合物的分子结构和离子间磁性相互作用具有非常重要的意义,拟通过N,N′-二（邻-羟基-3-甲氧基苯甲基）草酰（H4L）,[Cu2L]2.3H2O和Ln（acac）3.3H2O以摩尔比2∶1∶4的比例在N,N′-二甲亚砜中反应,合成含有3d-4f磁性离子相互作用的配合物CuLLn（acac）。同时,采用紫外-可见光谱法对该混合溶液的自组装反应过程进行跟踪监测,观察到了自组装反应过程。然而,从溶液中得到的蓝色晶体是Cu（acac）2,粉色粉末是LnHL。该反应过程为：2Ln（acac）3＋Cu2L＋H4L=2LnHL＋2Cu（acac）2＋2Hacac。     

Constructing supramolecular nanostructure by hydrogen-bonding

The diquinoxalino （2.3-2＂.3＂-a.c） phenazine （DQP）, containing 6 nitrogen atoms, was synthesized, and its adsorption and self-assembling behavior on highly oriented pyrolytic graphite （HOPG） was studied by scanning tunneling microscopy （STM） under ambient conditions. With 1,14-tetradecanedioic acid as a bridge, uniform two-dimensional arrays of 1,14-tetradecanedioic acid/DQP nanostructure were successfully fabricated. The result illustrates that it is possible to construct and control supramolecular nanostructure by intermolecular hydrogen-bonding.     

棒/线两嵌段共聚物共混体系的自组装

运用二维格子自洽场方法,研究棒/线两嵌段共聚物共混体系的自组装.结果表明:在长/短两种嵌段体积比相等的棒/线两嵌段共聚物共混体系中,当某种共聚物的混合比较大时,观察到层状结构,层的厚度与混合比大的嵌段共聚物长度有关;在两种嵌段共聚物混合比相差较小的条件下,出现了新的自组装结构,即柱层和层与柱共存相,这两种结构未出现在棒/线内嵌段共聚物熔体体系中,它们的出现与棒/线两嵌段共聚物链构象的不对称性及共混的影响有关.     

内含肽介导的鼠多瘤病毒样颗粒生产表达和纯化

鼠多瘤病毒样颗粒(VLPs)可由结构蛋白VP1自组装而成,可用于疫苗开发、基因治疗、药物传递和生物材料等方面.针对目前VP1生产中需要凝血酶去除谷胱甘肽S-转移酶(GST)标签,生产成本较高、操作复杂的问题,利用内含肽(intein)自剪切的特征,将内含肽插入到VP1与GST标签之间进行融合表达,表达产物经亲和色谱纯化,并通过改变柱内pH值、温度诱导内含肽剪切,使VP1与GST-intein分离从而获得VP1蛋白,产量为4,mg/(L培养基).纯化的VP1可自组装成与天然鼠多瘤病毒样颗粒一致的VLPs.结果表明,内含肽介导鼠多瘤病毒样颗粒生产纯化流程简单易行,且无需凝血酶参与,大幅降低成本,为VLPs的高效制备奠定了基础.     

三维自组装:从多分散的纳米粒子到单分散的超级纳米粒子

如何将具有特殊光、电性能的单个无机纳米粒子按照人类的意愿构建成宏观尺度、具有特定结构和性质的集合体,一直是当今科学界最具挑战性的前沿课题之一。我们发现,尺寸分布不均一的无机纳米粒子能自发组装为尺寸均一、具有核/壳结构的超级纳米粒子。这种多分散纳米粒子的自限制生长过程由纳米粒子自身的库仑排斥力和范德华吸引力间的平衡所控制。对这些相互作用力本质的认识为纳米粒子组装基元的可控设计和合成提供了理论基础,并可用于构建包括具有分级结构的胶体晶体在内的各种自组装结构,为纳米粒子的实际应用提供了新途经。此外,该研究结果对于理解单分散性的病毒等生物体系和聚合物等有机大分子超结构的形成具有指导意义。     

二氧化硅微球的制备及自组装

先后通过一步法和改进的溶胶种子法制备了单分散二氧化硅(SiO2)亚微米微球,利用扫描电子显微镜(SEM)对样品的形貌进行了表征,同时系统地研究了氨水浓度、水的浓度、温度、硅源浓度和二次成核等不同反应条件对SiO2粒径和分散性的影响。最后采用缓慢干燥法和垂直沉积法对SiO2亚微米微球进行了自组装,用扫描电镜进行了表征。结果表明:所制备的SiO2亚微米微球尺寸均匀,单分散性好,符合自组装胶体晶体的要求。