Self-assembly Research Articles

Selective hydrothermally synthesis of hexagonal WS2 platelets and their photocatalytic performance under visible light irradiation

Hexagonal WS2 platelets have been synthesized via simple hydrothermal synthesis method. The hexagonal WS2 is formed by the oriented attachment (OA)-self-assembly (SA). The thickness of the WS2 platelets was between ∼20 and 100 nm. The specific surface area of these platelets is 94.63 m2 g−1. The hexagonal WS2 platelets exhibited excellent photocatalytic activity compared to irregular WS2 platelets for the degradation of rhodamine B (RhB) under visible light irradiation. This work paves the method for designing hexagonal shaped WS2 platelets with great potential for a wide spectrum of applications in photocatalysis. Moreover, this synthetic procedure may open up an opportunity to tailor the morphologies of the other nanomaterials especially transition metal sulfides.

Electric-Field-Induced Lock-and-Key Interactions between Colloidal Spheres and Bowls

To realize new and directed self-assembly (SA) pathways, the focus in colloid science and nanoscience has shifted from spherical particles and interactions to increasingly more complex shapes and interparticle potentials. This field is fueled by recent breakthroughs in particle synthesis, such as particles with complementary shapes that allow for specific lock-and-key interactions induced by depletants. Here, we show that electric fields form an alternative route for directing the SA of convex and concave colloids, with the additional advantage that the system now becomes switchable by external conditions. Both experimental and theoretical results are presented that validate the electric-field-induced assembly mechanism and show that even irreversibly bound composites can be generated by tuning the force balance. The successful isolation of the irreversible composite particles, in combination with generalization to different materials, shows that the current mechanism provides a versatile new path not onl...

Construction of Insulin 18-mer Nanoassemblies Driven by Coordination to Iron(II) and Zinc(II) Ions at Distinct Sites.

Controlled self-assembly (SA) of proteins offers the possibility to tune their properties or to create new materials. Herein, we present the synthesis of a modified human insulin (HI) with two distinct metal-ion binding sites, one native, the other abiotic, enabling hierarchical SA through coordination with two different metal ions. Selective attachment of an abiotic 2,2'-bipyridine (bipy) ligand to HI, yielding HI-bipy, enabled Zn(II)-binding hexamers to SA into trimers of hexamers, [[HI-bipy]6]3, driven by octahedral coordination to a Fe(II) ion. The structures were studied in solution by small-angle X-ray scattering and on surfaces with AFM. The abiotic metal ligand had a higher affinity for Fe(II) than Zn(II) ions, enabling control of the hexamer formation with Zn(II) and the formation of trimers of hexamers with Fe(II) ions. This precise control of protein SA to give oligomers of oligomers provides nanoscale structures with potential applications in nanomedicine.

Construction of Insulin 18‐mer Nanoassemblies Driven by Coordination to Iron(II) and Zinc(II) Ions at Distinct Sites

AbstractControlled self‐assembly (SA) of proteins offers the possibility to tune their properties or to create new materials. Herein, we present the synthesis of a modified human insulin (HI) with two distinct metal‐ion binding sites, one native, the other abiotic, enabling hierarchical SA through coordination with two different metal ions. Selective attachment of an abiotic 2,2′‐bipyridine (bipy) ligand to HI, yielding HI–bipy, enabled ZnII‐binding hexamers to SA into trimers of hexamers, [[HI–bipy]6]3, driven by octahedral coordination to a FeII ion. The structures were studied in solution by small‐angle X‐ray scattering and on surfaces with AFM. The abiotic metal ligand had a higher affinity for FeII than ZnII ions, enabling control of the hexamer formation with ZnII and the formation of trimers of hexamers with FeII ions. This precise control of protein SA to give oligomers of oligomers provides nanoscale structures with potential applications in nanomedicine.

JoVE - Year in Review: 2015

In January 2015, JoVE Developmental Biology became the newest addition to the JoVE family, and featured a live-imaging protocol for visualizing the developing Drosophila eye. In February, JoVE Medicine showed state-of-the-art cranial ultrasound imaging in neonates. Advances in this technique have improved its diagnostic value, allowing timely therapeutic intervention. In March, JoVE Environment featured dendroecology, the science of using tree rings to study ecological effects of specific environmental factors. In April, JoVE Biology examined a mode of bacterial motility called swarming with a two-phase swarm assay. that can be used to study various aspects of bacterial growth. In May, JoVE Chemistry described the self-assembly of single-stranded DNA tiles into complex 2D shapes. This demonstrated the principles of DNA tiling as an approach for making programmable nanostructures. June 2015 marked the release of JoVE's 100th issue, and in JoVE Behavior, we featured protocols for assessing cognition, including a method of quantifying learning in young infants by tracking leg movements. In July, JoVE Medicine presented a method for measuring halitosis in dogs by taking breath samples, and performing gas chromatography. This assay could be used in trials of dog food formulated to fight bad breath in our canine companions. In August, JoVE Bioengineering contained a protocol for bioengineering kidney tissues. Kidneys are decellularized by perfusion, and repopulated with human renal cells, This promising technology can lead to kidney grafts made from a patient's own cells. In September, JoVE Environment examined herbicide resistance, which threatens commercial crop production. An excised leaf assay determines the rates of herbicide metabolism, which is useful for studying the metabolic basis of resistance. In October, JoVE Neuroscience featured a method for interfacing 3D neuronal cultures to micro-electrode arrays. The complex 3D assemblies closely approximate in vivo neural networks. November's edition of JoVE Behavior showcased the natural human ability to acquire new motor skills, which is central in a structured rehabilitation program for amputees as they learn how to use multifunctional prosthetics. In December, JoVE Immunology & Infection prepared us for the impending flu season with an easy protocol for sampling influenza in pigs. Because swine are important hosts for flu viruses, this method helps to monitor virus evolution and currently circulating strains. This Year in Review was just a sampling of more than 900 video-articles that JoVE published in 2015. Browse the JoVE archives for thousands of other videos, and come back each week to see brand-new material in JoVE: The Journal of Visualized Experiments.

重合誘起自己組織化によるナノ組織の合成

重合誘起自己組織化によるナノ組織の合成

Self-assembly in the World of Polymers

Self-assembly in the World of Polymers

Supramolecular self-assembly of N-acetyl Beta3-peptide amphiphiles

Event Abstract Back to Event Supramolecular self-assembly of N-acetyl Beta3-peptide amphiphiles Nathan Habila1, Ketav P. Kulkarni1, Tzong-Hsien Lee1, Mark P. Del Borgo1 and Mibel I. Aguilar1 1 Monash University, Biochemistry and Molecular Biology, Australia Self-assembly (SA) of peptides provides a flexible approach to developing novel materials with tailored morphologies and desired functions by modulating design and engineering of monomers[1]-[3]. Natural amino acids have been frequently utilized in the design of sequences. Although promising, they still have some draw backs in terms of structural and metabolic stability as well as ease of functionalization[4]. Using peptides consisting of only β-amino acids offers the means to overcome these limitations. Recently, our group reported that N-terminal acetylated β3-peptides can self-assemble by head-to-tail into helical fibrils through a supramolecular three point H-bonding motif[5]. We have also tuned the self-assembly of β3-peptides to present a range of morphologies by the appropriate solvent medium[6]. In order to further understand the control of self-assembly and engineer new architectures, here we show a new class of β3-peptide amphiphiles consisting of alkyl chains of either C12, C14 or C16 that can self-assemble in a unique pattern. Self-assembly was investigated using atomic force microscopy and transmission electron microscopy. The alkyl chain was attached at different positions and β3-peptide amphiphiles with identical composition but with a different sequence arrangement and position of alkyl chain self-assembled into different types of nanostructures under the same conditions. We found that β3-peptide amphiphiles with the alkyl chain on the N-terminus or residue 1 self-assembled into twisted fibrous nanostructures. By comparison, when the alkyl chain is located at residue 2 or 3, self-assembly resulted in flat nanobelts. The results clearly demonstrate the significance of the position of an alkyl chain on the peptide backbone sequence in determining supramolecular architectures. These outcomes will give further insight into the design and control of β3-peptide amphiphile self-assembly.

Fabrication and self-assembly of nanobiomaterials: applications of nanobiomaterials

Fabrication and self-assembly of nanobiomaterials: applications of nanobiomaterials

Hybrid Cyclic Water–Chloride Cluster Self-assembled in a Ruthenium(II) Polypyridyl Complex

A two-dimensional cyclic water–chloride anionic {[H2O)18(Cl)8]8−}n network has been identified in a ruthenium(II) complex [Ru(bpy)2(tdzp)]2·tdzp·Cl4·9H2O (bpy = 2,2′-bipyridine, tdzp = [1,2,5]-thiadiazolo-[3,4-f]-[1,10]-phenanthroline). The compound crystallized in monoclinic space group P21/c. A two-dimensional cyclic water-chloride anionic {[H2O)18(Cl)8]8−}n network has been identified in a ruthenium(II) complex [Ru(bpy)2(tdzp)]2⋅tdzp⋅Cl4⋅9H2O (bpy=2,2′-bipyridine, tdzp=[1,2,5]-thiadiazolo-[3,4-f]-[1,10]-phenanthroline).

Self-assembled films based on polyaniline/multiwalled carbon nanotubes composites and sulphonated polystyrene deposited onto ITO substrates

In this work, a self-assembled (SA) film based on a composite of polyaniline (PAni) and functionalized carbon nanotubes (MWCNT) with alternated layers of sulphonated polystyrene (PSS) was produced and characterized. Two other SA films (PAni/PSS/MWCNT/PSS and PAni/PSS) were produced to compare the results. The composite PAni-MWCNT was characterized by scanning electron microscopy (SEM) and Fourier transformed infrared (FTIR) analysis. The results showed that the synthesis procedure was effective in covering the MWCNTs surface by PAni particles. The SA films were characterized by scanning electron microscopy (SEM), UV–vis spectrophotometry (UV–vis) and cyclic voltammetry (CV) techniques. SEM images showed that morphologies of PANi/PSS and PAni-MWCNT/PSS were similar. The UV–vis and CV results indicated increase of absorbance values as well as the current signals for each bilayer deposited. However, SA film with PAni composite (PAni-MWCNT/PSS) presented a significant increase in its current peaks. The authors suggested that the increase in the current peaks was attributed to a synergic effect of the PAni-MWCNT composite with the subsequent decrease of the charge transfer resistance and, consequently, increase of the film conductivity. These results can be used by promoting these films as possible sensors or biosensors.

Synthesis and hierarchical self-assembly of molecularly ordered phenyl-bridged mesoporous silica nanofilaments

Synthesis and hierarchical self-assembly of molecularly ordered phenyl-bridged mesoporous silica nanofilaments

Foldectures from the Self‐Assembly of Racemic Foldamers

Foldectures from the Self‐Assembly of Racemic Foldamers

Corrosion Inhibition of Self-assembled Monolayer of Phytic Acid for HAl77-2 Brass

The effect of phytic acid concentration, self-assembling time and concentration of sodium molybdate on the corrosion inhibition of the selfassembled monolayer of phytic acid for HAl77-2 brass was investigated by using potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and dezincification factor analysis etc. The results showed that with the increase of phytic acid concentration, the corrosion current density of HAl77-2 brass decreased first and then increased; with the increase of assembling time, the phytic acid layeron HAl772 brass became denser, however with further increase of time (for example upto 16 h), the self-assembled layer of phytic acid turned to be aged and spalled off, correspondingly, the corrosion current density increased and the impedance arc radius decreased for the brass electrode. The corrosion inhibition of the phytic acid on HAl77-2 brass was significantly increased with the addition of sodium molybdate. Besides, the synergistic action of phytic acid and sodium molybdate can weaken the dezincification of brass obviously. These results provide theoretical support for the application of 定稿日期:2014-09-21 基金项目:国家科技支撑计划项目 (2013BAJ09B04)资助 作者简介:宋芳,女,1988年生,硕士生 通讯作者:陈友媛,E-mail:youyuan@ouc.edu.cn,研究方向为地下水资源利用 DOI:10.11902/1005.4537.2014.176

Crystallization and gelation: orthogonal self-assembly far from equilibrium

Crystallization and gelation: orthogonal self-assembly far from equilibrium

Self-Assembly Kinetics of Microscale Components: A Parametric Evaluation

At the microscale, assembly by grasp and release is challenging. Self-assembly (SA) is an alternative component assembly method to significantly reduce assembly equipment costs. However, successful application of SA requires high assembly rates and high yield (few process errors). Prior modeling efforts describe SA process performance (yield and rate) for specific system configurations, but they do not use measurable process parameters and provide limited ability to predict the impact of process changes. In this paper, an experimental SA system was designed that controls process parameters independently while measuring SA outcomes. This system is used to evaluate a simple parameterization model for SA rate. The travel direction of the parts is varied to measure the path dependence of the assembly probability in the limit of low-impact velocity. Moreover, effects from changing part geometry are evaluated and accounted for in the model. Experimental results show a strong part-geometry dependence and minimal dependence on part arrival angle. This information is a key step toward a parametric kinetic model of capillary SA and complements previous SA process modeling efforts. [2014-0009]

混合配体构筑的Zn(II)金属有机骨架化合物的合成、 结构与荧光性质

在水热条件下, 利用锌离子与2种有机配体合成出1个结构新颖的金属有机骨架化合物[Zn 2 (BPDC)(IN) 2 ] (H 2 BPDC=4,4'-联苯二羧酸; HIN=异烟酸), 并通过单晶X射线衍射、红外光谱、热重分析和荧光光谱等对该化合物进行了表征. 结果表明, 该化合物结构中Zn离子与BPDC的羧基形成双核金属次级结构单元[Zn 2 (-CO 2 ) 2 (IN) 2 ], 相邻次级结构单元通过IN配离子连接形成[Zn 2 (-CO 2 ) 2 (IN) 2 ] ∞ 二维层面, 相邻的二维层通过BPDC相互连接形成具有三重互穿的简单格子拓扑结构. 该化合物表现出良好的荧光性质.

Back Cover: Growth of Single‐Layered Two‐Dimensional Mesoporous Polymer/Carbon Films by Self‐Assembly of Monomicelles at the Interfaces of Various Substrates (Angew. Chem. Int. Ed. 29/2015)

Back Cover: Growth of Single‐Layered Two‐Dimensional Mesoporous Polymer/Carbon Films by Self‐Assembly of Monomicelles at the Interfaces of Various Substrates (Angew. Chem. Int. Ed. 29/2015)

Colorimetric-based detection of TNT explosives using functionalized silica nanoparticles.

This proof-of-concept study proposes a novel sensing mechanism for selective and label-free detection of 2,4,6-trinitrotoluene (TNT). It is realized by surface chemistry functionalization of silica nanoparticles (NPs) with 3-aminopropyl-triethoxysilane (APTES). The primary amine anchored to the surface of the silica nanoparticles (SiO2-NH2) acts as a capturing probe for TNT target binding to form Meisenheimer amine–TNT complexes. A colorimetric change of the self-assembled (SAM) NP samples from the initial green of a SiO2-NH2 nanoparticle film towards red was observed after successful attachment of TNT, which was confirmed as a result of the increased separation between the nanoparticles. The shift in the peak wavelength of the reflected light normal to the film surface (λpeak) and the associated change of the peak width were measured, and a merit function taking into account their combined effect was proposed for the detection of TNT concentrations from 10−12 to 10−4 molar. The selectivity of our sensing approach is confirmed by using TNT-bound nanoparticles incubated in AptamerX, with 2,4-dinitrotoluene (DNT) and toluene used as control and baseline, respectively. Our results show the repeatable systematic color change with the TNT concentration and the possibility to develop a robust, easy-to-use, and low-cost TNT detection method for performing a sensitive, reliable, and semi-quantitative detection in a wide detection range.

Self-assembly: a review of scope and applications.

Self-assembly (SA) is the preferred growth mechanism in the natural world, on scales ranging from the molecular to the macro-scale. It involves the assembling of components, which governed by a set of local interaction rules, lead to the formation of a global minimum energy structure. In this survey, the authors explore the extensive research conducted to exploit SA in three domains; first, as a bottom-up approach to fabricate semiconductor heterostructures and nano-scale devices composed of carbon nanotubes and nanowires; second, for meso-scale assembly to build systems such as three-dimensional electrical networks and microelectromechanical systems by utilising capillary force, external magnetic field and so on as the binding force; and third, as an emerging means to achieve computing via tiling, biomolecular automata and logic gates. DNA, in particular, has been a molecule of choice because of its easy availability, biological importance and high programmability as a result of its highly specific component bases.