WorldWideScience

Sample records for amelogenin supramolecular assembly

  1. Radiolytic syntheses of nanoparticles in supramolecular assemblies.

    Science.gov (United States)

    Chen, Qingde; Shen, Xinghai; Gao, Hongcheng

    2010-08-11

    Ionizing radiation is a powerful method in the syntheses of nanoparticles (NPs). The application of ionizing radiation in supramolecular assemblies can afford us more unique conditions to control the composition and morphology of the NPs. So far, most work focused on water-in-oil (W/O) microemulsions or reversed micelles. In this supramolecular organization, it has been proved that the effects of many conditions on the yield of e(aq)(-) play a key role, remarkably different from the mechanism in routine chemical method. Besides, some supramolecular assemblies of cyclodextrins and ionic liquids have been used in the syntheses of NPs by ionizing radiation, and many novel and interesting phenomena appeared. This review is intended to underline the three significant aspects of the radiolytic syntheses of NPs in supramolecular assemblies. PMID:20653087

  2. Supramolecular Sheet Co(Ⅱ) Complex Assembled by Hydrogen Bond

    Institute of Scientific and Technical Information of China (English)

    LIU Gui-lei; LI Hui; SONG Fang; QIN Yong-jie

    2009-01-01

    etwork, and then assembled into a three-dimensional supramolecular architecture through electrostatic and hydrophobic interaction. In the structure, supramolecular sheet was observed, which contains alternative organic and inorganic layers.

  3. Intrinsic nanoscale phase separation in miscible mixtures and supramolecular assemblies

    OpenAIRE

    Lei Zhang

    2011-01-01

    A model is used to describe the intrinsic nanoscale phase separation in miscible mixtures and supramolecular assemblies. Phase-separated nanostructures related to size-dependent surface tension, molecular structural factors and strong interphase interactions exist in miscible mixtures and supramolecular assemblies. The intrinsic nanoscale phase separation may exist universally in miscible mixtures.

  4. Supramolecular self-assemblies as functional nanomaterials

    Science.gov (United States)

    Busseron, Eric; Ruff, Yves; Moulin, Emilie; Giuseppone, Nicolas

    2013-07-01

    In this review, we survey the diversity of structures and functions which are encountered in advanced self-assembled nanomaterials. We highlight their flourishing implementations in three active domains of applications: biomedical sciences, information technologies, and environmental sciences. Our main objective is to provide the reader with a concise and straightforward entry to this broad field by selecting the most recent and important research articles, supported by some more comprehensive reviews to introduce each topic. Overall, this compilation illustrates how, based on the rules of supramolecular chemistry, the bottom-up approach to design functional objects at the nanoscale is currently producing highly sophisticated materials oriented towards a growing number of applications with high societal impact.

  5. Construction of Supramolecular Architectures via Self-assembly

    Institute of Scientific and Technical Information of China (English)

    Takeharu; Haino

    2007-01-01

    1 Results In this paper we report supramolecular polymeric nano networks formed by the molecular-recognition-directed self-assembly between a calix[5]arene and C60[1]. Covalently-linked double-calix[5]arenes take up C60 into their cavities[2]. This complementary interaction creates a strong non-covalent bonding; thus,the iterative self-assembly between dumbbell fullerene 1 and ditopic host 2 can produce the supramolecular polymer networks (See Fig.1).

  6. Supramolecular chirality in self-assembled peptide amphiphile nanostructures.

    Science.gov (United States)

    Garifullin, Ruslan; Guler, Mustafa O

    2015-08-11

    Induced supramolecular chirality was investigated in the self-assembled peptide amphiphile (PA) nanosystems. Having shown that peptide chirality can be transferred to the covalently-attached achiral pyrene moiety upon PA self-assembly, the chiral information is transferred to molecular pyrene via weak noncovalent interactions. In the first design of a supramolecular chiral system, the chromophore was covalently attached to a peptide sequence (VVAGH) via an ε-aminohexanoic acid spacer. Covalent attachment yielded a PA molecule self-assembling into nanofibers. In the second design, the chromophore was encapsulated within the hydrophobic core of self-assembled nanofibers of another PA consisting of the same peptide sequence attached to lauric acid. We observed that supramolecular chirality was induced in the chromophore by PA assembly into chiral nanostructures, whether it was covalently attached, or noncovalently bound. PMID:26146021

  7. Reversible Guest Exchange Mechanisms in Supramolecular Host-GuestAssemblies

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Raymond, Kenneth N.

    2006-09-01

    Synthetic chemists have provided a wide array of supramolecular assemblies able to encapsulate guest molecules. The scope of this tutorial review focuses on supramolecular host molecules capable of reversibly encapsulating polyatomic guests. Much work has been done to determine the mechanism of guest encapsulation and guest release. This review covers common methods of monitoring and characterizing guest exchange such as NMR, UV-VIS, mass spectroscopy, electrochemistry, and calorimetry and also presents representative examples of guest exchange mechanisms. The guest exchange mechanisms of hemicarcerands, cucurbiturils, hydrogen-bonded assemblies, and metal-ligand assemblies are discussed. Special attention is given to systems which exhibit constrictive binding, a motif common in supramolecular guest exchange systems.

  8. Design and assembly of supramolecular dual-modality nanoprobes

    Science.gov (United States)

    Liu, Shuang; Zhang, Pengcheng; Ray Banerjee, Sangeeta; Xu, Jiadi; Pomper, Martin G.; Cui, Honggang

    2015-05-01

    We report the design and synthesis of self-assembling dual-modality molecular probes containing both a fluorophore for optical imaging and a metal ion chelator for imaging with MRI or radionuclide methods. These molecular probes can spontaneously associate into spherical nanoparticles under physiological conditions. We demonstrate the use of these supramolecular nanoprobes for live-cell optical imaging, as well as their potential use as MRI contrast agents after complexation with gadolinium. Our results suggest that self-assembly into supramolecular nanoprobes presents an effective means to enhance and tune the relaxivities of molecular probes.We report the design and synthesis of self-assembling dual-modality molecular probes containing both a fluorophore for optical imaging and a metal ion chelator for imaging with MRI or radionuclide methods. These molecular probes can spontaneously associate into spherical nanoparticles under physiological conditions. We demonstrate the use of these supramolecular nanoprobes for live-cell optical imaging, as well as their potential use as MRI contrast agents after complexation with gadolinium. Our results suggest that self-assembly into supramolecular nanoprobes presents an effective means to enhance and tune the relaxivities of molecular probes. Electronic supplementary information (ESI) available: Experimental methods, materials, synthesis schemes, sample characterization, fluorescence measurements, cellular uptake and MRI experimental details. See DOI: 10.1039/c5nr01518a

  9. From supramolecular chemistry to nanotechnology : assembly of 3D nanostructures

    OpenAIRE

    Ling, Xing Yi

    2008-01-01

    Fabricating well-defined and stable nanoparticle arrays and crystals in a controlled fashion receives growing attention in nanotechnology owing to the potential application in optoelectronic devices, biological sensors, and photonic structures. The research described in this thesis aims to construct stable, ordered and functional 2D and 3D nanoparticle structures. Molecular recognition abilities have been exploited by using a combination of supramolecularly directed self-assembly of receptor-...

  10. Assembly and characterization of supramolecular architectures for biosensor applications

    OpenAIRE

    Xu, Fei

    2005-01-01

    The research has included the efforts in designing, assembling and structurally and functionally characterizing supramolecular biofunctional architectures for optical biosensing applications. In the first part of the study, a class of interfaces based on the biotin-NeutrAvidin binding matrix for the quantitative control of enzyme surface coverage and activity was developed. Genetically modified ß-lactamase was chosen as a model enzyme and attached to five different types of NeutrAvidi...

  11. Electrostatically Directed Self-Assembly of Ultrathin Supramolecular Polymer Microcapsules

    OpenAIRE

    Parker, Richard M.; Zhang, Jing; Zheng, Yu; Coulston, Roger J.; Smith, Clive A; Salmon, Andrew R; Yu, Ziyi; Oren A. Scherman; Abell, Chris

    2015-01-01

    Supramolecular self-assembly offers routes to challenging architectures on the molecular and macroscopic scale. Coupled with microfluidics it has been used to make microcapsules—where a 2D sheet is shaped in 3D, encapsulating the volume within. In this paper, a versatile methodology to direct the accumulation of capsule-forming components to the droplet interface using electrostatic interactions is described. In this approach, charged copolymers are selectively partitioned to the microdroplet...

  12. Novel biosensing platform based on self-assembled supramolecular hydrogel.

    Science.gov (United States)

    Ma, Dong; Zhang, Li-Ming

    2013-07-01

    The supramolecular hydrogel self-assembled from α-cyclodextrin (α-CD) and an amphiphilic triblock copolymer was used for the first time as a biosensing platform by the in-situ incorporation of horseradish peroxidase and polyaniline (PANI) nanoparticles. It was found that the used triblock copolymer could disperse well PANI nanoparticles in aqueous system and then interact with α-CD in the presence of horseradish peroxidase for the formation of supramolecular hydrogel composite. The content of PANI nanoparticles was found to affect the gelation time and gel strength. The circular dichroism analyses showed that the entrapped horseradish peroxidase could retain its native conformation. By electrochemical experiments, the incorporated PANI nanoparticles were confirmed to improve the current response and enzymatic activity, and the fabricated biosensor was found to provide a fast amperometric response to hydrogen peroxide. PMID:23623078

  13. Small molecule-guided thermoresponsive supramolecular assemblies

    KAUST Repository

    Rancatore, Benjamin J.

    2012-10-23

    Small organic molecules with strong intermolecular interactions have a wide range of desirable optical and electronic properties and rich phase behaviors. Incorporating them into block copolymer (BCP)-based supramolecules opens new routes to generate functional responsive materials. Using oligothiophene- containing supramolecules, we present systematic studies of critical thermodynamic parameters and kinetic pathway that govern the coassemblies of BCP and strongly interacting small molecules. A number of potentially useful morphologies for optoelectronic materials, including a nanoscopic network of oligothiophene and nanoscopic crystalline lamellae, were obtained by varying the assembly pathway. Hierarchical coassemblies of oligothiophene and BCP, rather than macrophase separation, can be obtained. Crystallization of the oligothiophene not only induces chain stretching of the BCP block the oligothiophene is hydrogen bonded to but also changes the conformation of the other BCP coil block. This leads to an over 70% change in the BCP periodicity (e.g., from 31 to 53 nm) as the oligothiophene changes from a melt to a crystalline state, which provides access to a large BCP periodicity using fairly low molecular weight BCP. The present studies have demonstrated the experimental feasibility of generating thermoresponsive materials that convert heat into mechanical energy. Incorporating strongly interacting small molecules into BCP supramolecules effectively increases the BCP periodicity and may also open new opportunities to tailor their optical properties without the need for high molecular weight BCP. © 2012 American Chemical Society.

  14. Preface: Special Topic on Supramolecular Self-Assembly at Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, Ludwig [Department of Chemistry and the Materials Science and Engineering Program, University of California - Riverside, Riverside, California 92521 (United States); Ernst, Karl-Heinz [EMPA, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dubendorf (Switzerland); Gao, Hong-Jun [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics,Chinese Academy of Sciences, Beijing 100190 (China); Thiel, Patricia A. [Department of Chemistry, Department of Materials Science and Engineering, Ames Laboratory,Iowa State University, Ames, Iowa 50011 (United States)

    2015-03-14

    Supramolecular self-assembly at surfaces is one of the most exciting and active fields in Surface Science today. Applications can take advantage of two key properties: (i) versatile pattern formation over a broad length scale and (ii) tunability of electronic structure and transport properties, as well as frontier orbital alignment. It provides a new frontier for Chemical Physics as it uniquely combines the versatility of Organic Synthesis and the Physics of Interfaces. The Journal of Chemical Physics is pleased to publish this Special Topic Issue, showcasing recent advances and new directions.

  15. Self-Assembled Supramolecular Architectures Lyotropic Liquid Crystals

    CERN Document Server

    Garti, Nissim

    2012-01-01

    This book will describe fundamentals and recent developments in the area of Self-Assembled Supramolecular Architecture and their relevance to the  understanding of the functionality of  membranes  as delivery systems for active ingredients. As the heirarchial architectures determine their performance capabilities, attention will be paid to theoretical and design aspects related to the construction of lyotropic liquid crystals: mesophases such as lamellar, hexagonal, cubic, sponge phase micellosomes. The book will bring to the reader mechanistic aspects, compositional c

  16. Metal-Directed Design of Supramolecular Protein Assemblies.

    Science.gov (United States)

    Bailey, J B; Subramanian, R H; Churchfield, L A; Tezcan, F A

    2016-01-01

    Owing to their central roles in cellular signaling, construction, and biochemistry, protein-protein interactions (PPIs) and protein self-assembly have become a major focus of molecular design and synthetic biology. In order to circumvent the complexity of constructing extensive noncovalent interfaces, which are typically involved in natural PPIs and protein self-assembly, we have developed two design strategies, metal-directed protein self-assembly (MDPSA) and metal-templated interface redesign (MeTIR). These strategies, inspired by both the proposed evolutionary roles of metals and their prevalence in natural PPIs, take advantage of the favorable properties of metal coordination (bonding strength, directionality, and reversibility) to guide protein self-assembly with minimal design and engineering. Using a small, monomeric protein (cytochrome cb562) as a model building block, we employed MDPSA and MeTIR to create a diverse array of functional supramolecular architectures which range from structurally tunable oligomers to metalloprotein complexes that can properly self-assemble in living cells into novel metalloenzymes. The design principles and strategies outlined herein should be readily applicable to other protein systems with the goal of creating new PPIs and protein assemblies with structures and functions not yet produced by natural evolution. PMID:27586336

  17. Self-assembly of supramolecularly engineered polymers and their biomedical applications.

    Science.gov (United States)

    Wang, Dali; Tong, Gangsheng; Dong, Ruijiao; Zhou, Yongfeng; Shen, Jian; Zhu, Xinyuan

    2014-10-18

    Noncovalent interactions provide a flexible method of engineering various chemical entities with tailored properties. Specific noncovalent interactions between functionalized small molecules, macromolecules or both of them bearing complementary binding sites can be used to engineer supramolecular complexes that display unique structure and properties of polymers, which can be defined as supramolecularly engineered polymers. Due to their dynamic tunable structures and interesting physical/chemical properties, supramolecularly engineered polymers have recently received more and more attention from both academia and industry. In this feature article, we summarize the recent progress in the self-assembly of supramolecularly engineered polymers as well as their biomedical applications. In view of different molecular building units, the supramolecularly engineered polymers can be classified into the following three major types: supramolecularly engineered polymers built by small molecules, supramolecularly engineered polymers built by small molecules and macromolecules, and supramolecularly engineered polymers built by macromolecules, which possess distinct morphologies, definite architectures and specific functions. Owing to the reversible nature of the noncovalent interactions, the supramolecularly engineered polymers have exhibited unique features or advantages in molecular self-assembly, for example, facile preparation and functionalization, controllable morphologies and structures, dynamic self-assembly processes, adjustable performance, and so on. Furthermore, the self-assembled supramolecular structures hold great potential as promising candidates in various biomedical fields, including bioimaging, drug delivery, gene transfection, protein delivery, regenerative medicine and tissue engineering. Such developments in the self-assembly of supramolecularly engineered polymers and their biomedical applications greatly promote the interdiscipline research among

  18. A solution NMR investigation into the impaired self-assembly properties of two murine amelogenins containing the point mutations T21→I or P41→T

    Energy Technology Data Exchange (ETDEWEB)

    Buchko, Garry W.; Lin, Genyao; Tarasevich, Barbara J.; Shaw, Wendy J.

    2013-08-26

    Amelogenesis imperfecta describes a group of inherited disorders that results in defective tooth enamel. Two disorders associated with human amelogenesis imperfecta are the point mutations T21?I or P40?T in amelogenin, the dominant protein present during the early stages of enamel biomineralization. The biophysical properties of wildtype murine amelogenin (M180) and two proteins containing the equivalent mutations in murine amelogenin, T21?I (M180-I) and P41?T (M180-T), were probed by NMR spectroscopy. At low protein concentration (0.1 mM), M180, M180-I, and M180-T are predomi- nately monomeric at pH 3.0 in 2% acetic acid and neither mutation produces a major structural change. Chemical shift perturbation studies as a function of protein (0.1–1.8 mM) or NaCl (0–400 mM) concentra- tions show that the mutations affect the self-association properties by causing self-assembly at lower protein or salt concentrations, relative to wildtype amelogenin, with the largest effect observed for M180-I. Under both conditions, the premature self-assembly is initiated near the N-terminus, providing further evidence for the importance of this region in the self-assembly process. The self-association of M180-I and M180-T at lower protein concentrations and lower ionic strengths than wildtype M180 may account for the clinical phenotypes of these mutations, defective enamel formation.

  19. From micelle supramolecular assemblies in selective solvents to isoporous membranes

    KAUST Repository

    Nunes, Suzana Pereira

    2011-08-16

    The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values. © 2011 American Chemical Society.

  20. Cucurbit[7]uriI-Based Vesicles Formed by Self-assembly of Supramolecular Amphiphiles

    Institute of Scientific and Technical Information of China (English)

    李佳锡; 周黎鹏; 罗全; 王永国; 张春秋; 卢伟; 徐家云; 刘俊秋

    2012-01-01

    Cucurbituril (CB), a well-known macrocyclic cavitand, has been used extensively to construct supramolecular aggregates. Based on host-guest intertactions, an adamantanyl derivative guest molecule was designed and syn- thesized to prepare a supramolecular amphiphile with cucurbit[7]uril. In aqueous solution, the cucurbit[7]uril based supramolecular amphiphiles self-assemble into well-defined vesicles, and their disassembly can be achieved by addition of excess competitive agent 1-adamantanamine hydrochloride. This vesicle functions as a new nanocapsule to encapsulate molecules within its hollow cavity. Through competitive disassembly of supramolecular amphiphiles, the vesicles behave as a novel drug delivery carrier.

  1. Incorporating bacteria as a living component in supramolecular self-assembled monolayers through dynamic nanoscale interactions

    NARCIS (Netherlands)

    Sankaran, Shrikrishnan; Kiren, Mustafa Can; Jonkheijm, Pascal

    2015-01-01

    Supramolecular assemblies, formed through noncovalent interactions, has become particularly attractive to develop dynamic and responsive architectures to address living systems at the nanoscale. Cucurbit[8]uril (CB[8]), a pumpkin shaped macrocylic host molecule, has been successfully used to constru

  2. Self-Assembled PDINH Supramolecular System for Photocatalysis under Visible Light.

    Science.gov (United States)

    Liu, Di; Wang, Jun; Bai, Xiaojuan; Zong, Ruilong; Zhu, Yongfa

    2016-09-01

    A self-assembled perylene-3,4,9,10-tetracarboxylic diimide(PDINH) supramolecular system consisting of all-organic PDINH molecule building blocks through non-covalent interactions works as a visible light photocatalyst with high activity.

  3. Progress in non-viral gene delivery systems fabricated via supramolecular assembly

    Institute of Scientific and Technical Information of China (English)

    WANG Youxiang; SHEN Jiacong

    2005-01-01

    Gene delivery systems are one of key issues that limit the development of gene therapy. The novel non-viral gene delivery systems fabricated via supramolecular assembly have begun to show increasing promising and applications in gene therapy due to its suitable nanometric size, controllable structure and excellent biocompatibility. In this review, the fundamental and recent progress of non-viral gene supramolecular assembly is reviewed. Artificial viruses--the future direction of non-viral gene delivery systems are also described.

  4. Supramolecular design of self-assembling nanofibers for cartilage regeneration.

    Science.gov (United States)

    Shah, Ramille N; Shah, Nirav A; Del Rosario Lim, Marc M; Hsieh, Caleb; Nuber, Gordon; Stupp, Samuel I

    2010-02-23

    Molecular and supramolecular design of bioactive biomaterials could have a significant impact on regenerative medicine. Ideal regenerative therapies should be minimally invasive, and thus the notion of self-assembling biomaterials programmed to transform from injectable liquids to solid bioactive structures in tissue is highly attractive for clinical translation. We report here on a coassembly system of peptide amphiphile (PA) molecules designed to form nanofibers for cartilage regeneration by displaying a high density of binding epitopes to transforming growth factor beta-1 (TGFbeta-1). Growth factor release studies showed that passive release of TGFbeta-1 was slower from PA gels containing the growth factor binding sites. In vitro experiments indicate these materials support the survival and promote the chondrogenic differentiation of human mesenchymal stem cells. We also show that these materials can promote regeneration of articular cartilage in a full thickness chondral defect treated with microfracture in a rabbit model with or even without the addition of exogenous growth factor. These results demonstrate the potential of a completely synthetic bioactive biomaterial as a therapy to promote cartilage regeneration. PMID:20133666

  5. Energy Landscapes for the Self-Assembly of Supramolecular Polyhedra

    Science.gov (United States)

    Russell, Emily R.; Menon, Govind

    2016-06-01

    We develop a mathematical model for the energy landscape of polyhedral supramolecular cages recently synthesized by self-assembly (Sun et al. in Science 328:1144-1147, 2010). Our model includes two essential features of the experiment: (1) geometry of the organic ligands and metallic ions; and (2) combinatorics. The molecular geometry is used to introduce an energy that favors square-planar vertices (modeling {Pd}^{2+} ions) and bent edges with one of two preferred opening angles (modeling boomerang-shaped ligands of two types). The combinatorics of the model involve two-colorings of edges of polyhedra with four-valent vertices. The set of such two-colorings, quotiented by the octahedral symmetry group, has a natural graph structure and is called the combinatorial configuration space. The energy landscape of our model is the energy of each state in the combinatorial configuration space. The challenge in the computation of the energy landscape is a combinatorial explosion in the number of two-colorings of edges. We describe sampling methods based on the symmetries of the configurations and connectivity of the configuration graph. When the two preferred opening angles encompass the geometrically ideal angle, the energy landscape exhibits a very low-energy minimum for the most symmetric configuration at equal mixing of the two angles, even when the average opening angle does not match the ideal angle.

  6. Random mutagenesis of amelogenin for engineering protein nanoparticles.

    Science.gov (United States)

    Bonde, Johan; Bülow, Leif

    2015-07-01

    Nanoparticles made from recombinant proteins offer excellent potential for several nanotechnological applications. However, only a very limited number of proteins are currently being used for such purposes due to limited availability and stability. Therefore, we have investigated the enamel matrix protein amelogenin as a new alternative protein for use as recombinant nanoparticles. Amelogenin is a robust protein that has the ability to self-assemble into nanosized particles termed nanospheres. This self-assembly property of amelogenin is highly pH-dependent, and modifications of the solubility behavior for amelogenin can be particularly important for some applications such as drug delivery, where responsiveness at a specific pH is an essential property. In this study, an amelogenin mutant library was created and used to screen amelogenin variants with modified solubility/aggregation profiles in response to externally applied pH changes. Fifty amelogenin mutants were identified and produced recombinantly, purified and characterized. Several mutants with distinct solubility profiles were obtained that could form uniform nanospheres, ranging from 30 to 60 nm in hydrodynamic diameter. The mutants displayed a shifted onset of pH-dependent aggregation compared to wild-type amelogenin. At physiological pH, some mutants formed soluble nanospheres, while others generated nanosphere aggregates, suggesting different practical uses for the different mutants. By mixing and co-assembling mutant and wild-type amelogenin at different ratios, the level of nanosphere aggregation could be tuned at a given pH. By exploring combinations of different amelogenin variants it is possible to control aggregation events in nanomedical applications where a specific pH response is required. PMID:25664685

  7. Sequence-defined Energetic Shifts Control the Disassembly Kinetics and Microstructure of Amelogenin Adsorbed onto Hydroxyapatite (100)

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Jinhui; Buchko, Garry W.; Shaw, Wendy J.; De Yoreo, Jim; Tarasevich, Barbara J.

    2015-11-03

    The interactions between proteins and surfaces are critical to a number of important processes including biomineralization, the biocompatibility of biomaterials, and the function of biosensors. Although many proteins exist as monomers or small oligomers, amelogenin is a unique protein that self-assembles into supramolecular structures called “nanospheres,” aggregates of 100’s of monomers that are 20-60 nm in diameter. The nanosphere quaternary structure is observed in solution, however, the quaternary structure of amelogenin adsorbed onto hydroxyapatite (HAP) surfaces is not known even though it may be important to amelogenin’s function in forming highly elongated and intricately assembled HAP crystallites during enamel formation. We report studies of the interactions of the enamel protein, amelogenin (rpM179), with a well-defined (100) face prepared by synthesis of large crystals of HAP. High resolution, in-situ atomic force microscopy (AFM) was used to directly observe protein adsorption onto HAP at the molecular level within an aqueous solution environment. Our study shows that the amelogenin nanospheres disassemble onto the HAP surface, breaking down into oligomeric (25-mer) subunits of the larger nanosphere. In some cases, the disassembly event is directly observed by in situ imaging for the first time. Quantification of the adsorbate amounts by size analysis led to the determination of a protein binding energy (17.1 kbT) to a specific face of HAP (100). The kinetics of disassembly are greatly slowed in aged solutions, indicating there are time-dependent increases in oligomer-oligomer binding interactions within the nanosphere. A small change in the sequence of amelogenin by the attachment of a histidine tag to the N-terminus of rpM179 to form rp(H)M180 results in the adsorption of a complete second layer on top of the underlying first layer. Our research elucidates how supramolecular protein structures interact and break down at surfaces and how small

  8. From metal-organic squares to porous zeolite-like supramolecular assemblies

    KAUST Repository

    Wang, Shuang

    2010-12-29

    We report the synthesis, structure, and characterization of two novel porous zeolite-like supramolecular assemblies, ZSA-1 and ZSA-2, having zeolite gis and rho topologies, respectively. The two compounds were assembled from functional metal-organic squares (MOSs) via directional hydrogen-bonding interactions and exhibited permanent microporosity and thermal stability up to 300 °C. © 2010 American Chemical Society.

  9. Amphiphiles Self-Assembly: Basic Concepts and Future Perspectives of Supramolecular Approaches

    Directory of Open Access Journals (Sweden)

    Domenico Lombardo

    2015-01-01

    Full Text Available Amphiphiles are synthetic or natural molecules with the ability to self-assemble into a wide variety of structures including micelles, vesicles, nanotubes, nanofibers, and lamellae. Self-assembly processes of amphiphiles have been widely used to mimic biological systems, such as assembly of lipids and proteins, while their integrated actions allow the performance of highly specific cellular functions which has paved a way for bottom-up bionanotechnology. While amphiphiles self-assembly has attracted considerable attention for decades due to their extensive applications in material science, drug and gene delivery, recent developments in nanoscience stimulated the combination of the simple approaches of amphiphile assembly with the advanced concept of supramolecular self-assembly for the development of more complex, hierarchical nanostructures. Introduction of stimulus responsive supramolecular amphiphile assembly-disassembly processes provides particularly novel approaches for impacting bionanotechnology applications. Leading examples of these novel self-assembly processes can be found, in fact, in biosystems where assemblies of different amphiphilic macrocomponents and their integrated actions allow the performance of highly specific biological functions. In this perspective, we summarize in this tutorial review the basic concept and recent research on self-assembly of traditional amphiphilic molecules (such as surfactants, amphiphile-like polymers, or lipids and more recent concepts of supramolecular amphiphiles assembly which have become increasingly important in emerging nanotechnology.

  10. Green fluorescent protein nanopolygons as monodisperse supramolecular assemblies of functional proteins with defined valency

    Science.gov (United States)

    Kim, Young Eun; Kim, Yu-Na; Kim, Jung A.; Kim, Ho Min; Jung, Yongwon

    2015-05-01

    Supramolecular protein assemblies offer novel nanoscale architectures with molecular precision and unparalleled functional diversity. A key challenge, however, is to create precise nano-assemblies of functional proteins with both defined structures and a controlled number of protein-building blocks. Here we report a series of supramolecular green fluorescent protein oligomers that are assembled in precise polygonal geometries and prepared in a monodisperse population. Green fluorescent protein is engineered to be self-assembled in cells into oligomeric assemblies that are natively separated in a single-protein resolution by surface charge manipulation, affording monodisperse protein (nano)polygons from dimer to decamer. Several functional proteins are multivalently displayed on the oligomers with controlled orientations. Spatial arrangements of protein oligomers and displayed functional proteins are directly visualized by a transmission electron microscope. By employing our functional protein assemblies, we provide experimental insight into multivalent protein-protein interactions and tools to manipulate receptor clustering on live cell surfaces.

  11. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity.

    Science.gov (United States)

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J; Dong, He

    2015-12-01

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.

  12. Controlling Electronic Transitions in Fullerene van der Waals Aggregates via Supramolecular Assembly.

    Science.gov (United States)

    Das, Saunak; Herrmann-Westendorf, Felix; Schacher, Felix H; Täuscher, Eric; Ritter, Uwe; Dietzek, Benjamin; Presselt, Martin

    2016-08-24

    Morphologies crucially determine the optoelectronic properties of organic semiconductors. Therefore, hierarchical and supramolecular approaches have been developed for targeted design of supramolecular ensembles of organic semiconducting molecules and performance improvement of, e.g., organic solar cells (OSCs), organic light emitting diodes (OLEDs), and organic field-effect transistors (OFETs). We demonstrate how the photonic properties of fullerenes change with the formation of van der Waals aggregates. We identified supramolecular structures with broadly tunable absorption in the visible spectral range and demonstrated how to form aggregates with targeted visible (vis) absorption. To control supramolecular structure formation, we functionalized the C60-backbone with polar (bis-polyethylene glycol malonate-MPEG) tails, thus yielding an amphiphilic fullerene derivative that self-assembles at interfaces. Aggregates of systematically tuned size were obtained from concentrating MPEGC60 in stearic acid matrices, while different supramolecular geometries were provoked via different thin film preparation methods, namely spin-casting and Langmuir-Blodgett (LB) deposition from an air-water interface. We demonstrated that differences in molecular orientation in LB films (C2v type point group aggregates) and spin-casting (stochastic aggregates) lead to huge changes in electronic absorption spectra due to symmetry and orientation reasons. These differences in the supramolecular structures, causing the different photonic properties of spin-cast and LB films, could be identified by means of quantum chemical calculations. Employing supramolecular assembly, we propounded that molecular symmetry in fullerene aggregates is extremely important in controlling vis absorption to harvest photons efficiently, when mixed with a donor molecule, thus improving active layer design and performance of OSCs. PMID:27482718

  13. Self-assembled and responsive supramolecular nanoparticles mediated by cucurbit[8]uril host-guest interactions

    NARCIS (Netherlands)

    Stoffelen, Carmen

    2015-01-01

    Supramolecular nanoparticles (SNPs) have gained large interest in nanoscience because stable, but reversible three-dimensional assemblies can be used for a variety of applications, ranging from stimuli-responsive and self-healing materials to biomedical applications. In particular soft SNPs are prom

  14. Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates

    KAUST Repository

    Li, Zhong’an

    2015-09-09

    An understanding of structure–property relationships in cyanine dyes is critical for their design and application. Anionic and cationic cyanines can be organized into complementary cyanine salts, offering potential building blocks to modulate their intra/intermolecular interactions in the solid state. Here, we demonstrate how the structures of these complementary salts can be tuned to achieve highly ordered J-type supramolecular aggregate structures of heptamethine dyes in crystalline solids.

  15. Macromolecularly crowded in vitro microenvironments accelerate the production of extracellular matrix-rich supramolecular assemblies

    OpenAIRE

    Kumar, Pramod; Satyam, Abhigyan; Fan, Xingliang; Rodriguez, Brian J.; et al

    2015-01-01

    Therapeutic strategies based on the principles of tissue engineering by self-assembly put forward the notion that functional regeneration can be achieved by utilising the inherent capacity of cells to create highly sophisticated supramolecular assemblies. However, in dilute ex vivo microenvironments, prolonged culture time is required to develop an extracellular matrix-rich implantable device. Herein, we assessed the influence of macromolecular crowding, a biophysical phenomenon that regulate...

  16. Supramolecular Electrochemistry

    Science.gov (United States)

    Kaifer, Angel E.; Gomez-Kaifer, Marielle

    1999-12-01

    This book describes the electrochemical behavior of supramolecular systems. Special emphasis will be given to the electrochemistry of host-guest complexes, monolayer and multilayer assemblies, dendrimers, and other supramolecular assemblies. A fundamental theme throughout the book is to explore the effects that supramolecular structure exerts on the thermodynamics and kinetics of electrochemical reactions. Conversely, attention will be placed to the various ways in which electrochemical or redox conversions can be utilized to control or affect the structure or properties of supramolecular systems. This first book on this topic will be of value for graduate students and advanced researchers in both electrochemistry and supramolecular chemistry.

  17. Protein-responsive assemblies from catechol-metal ion supramolecular coordination.

    Science.gov (United States)

    Yuan, C; Chen, J; Yu, S; Chang, Y; Mao, J; Xu, Y; Luo, W; Zeng, B; Dai, L

    2015-03-21

    Supramolecular self-assembly driven by catechol-metal ion coordination has gained great success in the fabrication of functional materials including adhesives, capsules, coatings and hydrogels. However, this route has encountered a great challenge in the construction of nanoarchitectures in the absence of removable templates, because of the uncontrollable crosslinking of catechol-metal ion coordination. Herein, we show that a supramolecular approach, combining both catechol-metal ion coordination and polymer self-assembly together, can organize polymers into hybrid nanoassemblies ranging from solid particles, homogeneous vesicles to Janus vesicles. Without the introduction of a specific binding ligand or complicated molecular design, these assemblies can totally disassemble in response to proteins. UV/vis absorption, fluorescence quenching and recovery investigations have confirmed that proteins can seize metal ions from the hybrid nanoassemblies, thus causing the degradation of catechol-metal ion coordination networks.

  18. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity

    Science.gov (United States)

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J.; Dong, He

    2015-11-01

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would

  19. A novel nanostructured supramolecular hydrogel self-assembled from tetraphenylethylene-capped dipeptides.

    Science.gov (United States)

    Yeh, Mei-Yu; Huang, Chen-Wei; Chang, Jui-Wen; Huang, Yu-Tang; Lin, Jhong-Hua; Hsu, Shu-Min; Hung, Shih-Chieh; Lin, Hsin-Chieh

    2016-08-14

    Herein, we report a tetraphenylethylene-diglycine (TPE-GG) hydrogelator from a systematic study of TPE-capped dipeptides with various amphiphilic properties. From a chemical design, we found that the hydrogelation of TPE-GG molecules can be utilized to generate supramolecular nanostructures with a large TPE-based nanobelt width (∼300 nm) and lateral dimension ratio (>30 fold). In addition, TPE-GG has the lowest molecular weight and minimum number of atoms compared to any TPE-capped peptide hydrogelator reported to date. This minimal self-assembled hydrogelator can fundamentally achieve the gel features compared with other TPE-capped peptides. A combined experimental and computational study indicates the π-π interactions, electrostatic interactions and hydrogen-bonding interactions are the major driving forces behind the formation of self-assembled nanobelts. This study demonstrates the importance of structure-property relationships and provides new insights into the design of supramolecular nanomaterials. PMID:27381445

  20. Supramolecular chiral host-guest nanoarchitecture induced by the selective assembly of barbituric acid derivative enantiomers

    Science.gov (United States)

    Sun, Xiaonan; Silly, Fabien; Maurel, Francois; Dong, Changzhi

    2016-10-01

    Barbituric acid derivatives are prochiral molecules, i.e. they are chiral upon adsorption on surfaces. Scanning tunneling microscopy reveals that barbituric acid derivatives self-assemble into a chiral guest-host supramolecular architecture at the solid-liquid interface on graphite. The host nanoarchitecture has a sophisticated wavy shape pattern and paired guest molecules are nested insides the cavities of the host structure. Each unit cell of the host structure is composed of both enantiomers with a ratio of 1:1. Furthermore, the wavy patterns of the nanoarchitecture are formed from alternative appearance of left- and right-handed chiral building blocks, which makes the network heterochiral. The functional guest-host nanoarchitecture is the result of two-dimensional chiral amplification from single enantiomers to organizational heterochiral supramolecular self-assembly.

  1. Supramolecular nanoparticles generated by the self-assembly of polyrotaxanes for antitumor drug delivery

    OpenAIRE

    Liu R; Lai YS; He B; Li Y; Wang G; Chang S; Gu Z

    2012-01-01

    Rong Liu,1,2,* Yusi Lai,1,* Bin He,1 Yuan Li,1 Gang Wang,1 Shuang Chang,1 Zhongwei Gu1 1National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China; 2Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China*These authors contributed equally to this paperAbstract: A new approach of fabricating supramolecular nanoparticles generated by self-assembly polyrotaxanes for antitumor drug delivery has been reported. Cinnamic-acid-modified poly(ethy...

  2. Supramolecular Crafting of Self-Assembling Camptothecin Prodrugs with Enhanced Efficacy against Primary Cancer Cells

    OpenAIRE

    Su, Hao; Zhang, Pengcheng; Cheetham, Andrew G.; Koo, Jin Mo; Lin, Ran; Masood, Asad; Schiapparelli, Paula; Quiñones-Hinojosa, Alfredo; Cui, Honggang

    2016-01-01

    Chemical modification of small molecule hydrophobic drugs is a clinically proven strategy to devise prodrugs with enhanced treatment efficacy. While this prodrug strategy improves the parent drug's water solubility and pharmacokinetic profile, it typically compromises the drug's potency against cancer cells due to the retarded drug release rate and reduced cellular uptake efficiency. Here we report on the supramolecular design of self-assembling prodrugs (SAPD) with much improved water solubi...

  3. Development of Self-Assembled Supramolecular Catalysts and Their Applications to Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Shiro IKEGAMI

    2005-01-01

    @@ 1Introduction In modern synthetic organic chemistry, the development of efficient reagent or catalyst recycling systems is regarded as one of the most important topics. We have previously reported a self-assembled process between poly(N-isopropylacrylamide) (PNIPAAm) based polymer ligands and an inorganic species[1]. This process afforded a networked supramolecular complex where the polymers are cross-linked together by the inorganic species. Thus obtained complex was insoluble in water and worked as an efficient triphase catalyst.

  4. Tuning Cellular Uptake of Molecular Probes by Rational Design of Their Assembly into Supramolecular Nanoprobes.

    Science.gov (United States)

    Lock, Lye Lin; Reyes, Claudia D; Zhang, Pengcheng; Cui, Honggang

    2016-03-16

    Intracellular sensing of pathologically relevant biomolecules could provide essential information for accurate evaluation of disease staging and progression, yet the poor cellular uptake of water-soluble molecular probes limits their use as protease sensors. In other cases such as extracellular sensing, cellular uptake should be effectively inhibited. Self-assembly of molecular probes into supramolecular nanoprobes presents a potential strategy to alter their interaction mechanisms with cells to promote or reduce their cellular uptake. Here, we report on the design, synthesis, and assembly of peptide-based molecular beacons into supramolecular protease sensors of either spherical or filamentous shapes. We found that positively charged spherical nanobeacons demonstrate much higher cellular uptake efficiency than its monomeric form, thus making them most suitable for intracellular sensing of the lysosomal protease cathepsin B. Our results also suggest that assembly into filamentous nanobeacons significantly reduces their internalization by cancer cells, an important property that can be utilized for probing extracellular protease activities. These studies provide important guiding principles for rational design of supramolecular nanoprobes with tunable cellular uptake characteristics.

  5. Directed flexibility: self-assembly of a supramolecular tetrahedron.

    Science.gov (United States)

    Ludlow, James M; Xie, Tingzheng; Guo, Zaihong; Guo, Kai; Saunders, Mary Jane; Moorefield, Charles N; Wesdemiotis, Chrys; Newkome, George R

    2015-03-01

    Self-assembly of a tribenzo-27-crown-9 ether functionalized with six terpyridines generated (85%) an expanded tetrahedral structure comprised of four independent triangular surfaces interlinked by crown ether vertices.

  6. Use of human amelogenin in molecular encapsulation for the design of pH responsive microparticles

    Directory of Open Access Journals (Sweden)

    Bonde Johan

    2012-05-01

    Full Text Available Abstract Background Proteins can be used in drug delivery systems to improve pharmacological properties of an active substance. Differences in pH between tissues can be utilized in order to achieve a targeted drug release at a specific location or tissue, such as a tumor. The enamel matrix protein amelogenin has a pH dependent solubility profile and self-assemble to form aggregates at neutral pH. This could make amelogenin useful in the design of pH responsive drug delivery systems. Results In this study amelogenin was evaluated as a pH responsive component in drug delivery applications. This was achieved by testing the ability of amelogenin to entrap/release other proteins upon changes in pH, and by testing if amelogenin could confer pH responsiveness to an existing and versatile drug delivery system, such as gelatin microparticles. Amelogenin was able to encapsulate bovine serum albumin and insulin, whichwere used as model target proteins. The composite aggregates of amelogenin and target protein were formed at neutral pH and could be reversibly solubilized at weakly acidic pH. Gelatin microparticles prepared in the presence of amelogenin, showed a modulated structure in response to pH change, when studied by scanning electron microscopy, compared to particles without amelogenin. At neutral pH amelogenin induced formation of pores in the particle surface, which were not present at acidic pH, or in particles lacking amelogenin. Conclusions The results from this study demonstrate that amelogenin can be a useful component in drug delivery systems in order to achieve a pH dependent response.

  7. Expanding the structural diversity of self-assembling dendrons and supramolecular dendrimers via complex building blocks.

    Science.gov (United States)

    Percec, Virgil; Won, Betty C; Peterca, Mihai; Heiney, Paul A

    2007-09-12

    The design and synthesis of the first examples of AB4 and AB5 dendritic building blocks with complex architecture are reported. Structural and retrostructural analysis of supramolecular dendrimers self-assembled from hybrid dendrons based on different combinations of AB4 and AB5 building blocks with AB2 and AB3 benzyl ether dendrons demonstrated that none of these new hybrid dendrons exhibit the previously encountered conformations of libraries of benzyl ether dendrons. These hybrid dendrons enabled the discovery of some highly unusual tapered and conical dendrons generated by the intramolecular back-folding of their repeat units and of their apex. The new back-folded tapered dendrons have double thickness and self-assemble into pine-tree-like columns exhibiting a long-range 7/2 helical order. The back-folded conical dendrons self-assemble into spherical dendrimers. Non-back-folded truncated conical dendrons were also discovered. They self-assemble into spherical dendrimers with a less densely packed center. The discovery of dendrons displaying a novel crown-like conformation is also reported. Crown-like dendrons self-assemble into long-range 5/1 helical pyramidal columns. The long-range 7/2 and 5/1 helical structures were established by applying, for the first time, the helical diffraction theory to the analysis of X-ray patterns obtained from oriented fibers of supramolecular dendrimers. PMID:17705390

  8. Regulated assembly of a supramolecular centrosome scaffold in vitro

    DEFF Research Database (Denmark)

    Woodruff, J. B.; Wueseke, O.; Viscardi, V.;

    2015-01-01

    The centrosome organizes microtubule arrays within animal cells and comprises two centrioles surrounded by an amorphous protein mass called the pericentriolar material (PCM). Despite the importance of centrosomes as microtubule-organizing centers, the mechanism and regulation of PCM assembly are ...

  9. Supramolecular nanoparticles generated by the self-assembly of polyrotaxanes for antitumor drug delivery

    Science.gov (United States)

    Liu, Rong; Lai, Yusi; He, Bin; Li, Yuan; Wang, Gang; Chang, Shuang; Gu, Zhongwei

    2012-01-01

    A new approach of fabricating supramolecular nanoparticles generated by self-assembly polyrotaxanes for antitumor drug delivery has been reported. Cinnamic-acid-modified poly(ethylene glycol) chains were threaded in α-cyclodextrins to form polyrotaxanes. The polyrotaxanes self-assembled supramolecular nanoparticles. The morphology of the nanoparticles was changed from nanovesicle to micelle after the antitumor drug, doxorubicin, was loaded. The release profile of the drug-loaded nanoparticles was investigated, and it was found that the sustaining release time could last for 32 hours. The drug-loaded nanoparticles were co-cultured with mouse 4T1 breast cancer cells with a drug concentration of 10 μg/mL; the cell survival rate was 3.3% after a 72-hour incubation. In an in vivo study of breast cancer in a mouse model, the drug-loaded nanoparticles were injected in the tail veins of mice with a dose of 5 mg/kg body weight. The tumor inhibition rate of drug-loaded nanoparticles was 53%, which was better than that of doxorubicin hydrochloride. The cardiac toxicity of doxorubicin was decreased greatly after the encapsulation into supramolecular polyrotaxane nanoparticles. PMID:23055732

  10. Supramolecular Assemblies Using Piperazine with Dicarboxylic Acids and Hydroxy-carboxylic Acids

    Institute of Scientific and Technical Information of China (English)

    CHEN Zi-Yun; PENG Meng-Xia

    2008-01-01

    The molecular self-assembly of piperazine (pip) with 1,4-cyclohexanedicarboxylic acid (H2chda),m-phthalic acid (H2mpda),6-hydroxy-2-naphthalic acid (Hohna) and 1-hydroxy-2-naphthalic acid (Hshna) results in four new supramolecular networks formulated as H2pip·chda (1),H2pip·2Hmpda (2),HEpip·ohna·2H2O(3) and H2pip·shna (4),respectively.Single-crystal X-ray diffraction study reveals that compounds 1--3 are three-dimensional supramolecular networks,while 4 has a one-dimensional hydrogen-bonded chain-based structure,with CCDC:672051 (1),672052 (2),672053 (3) and 672054 (4).

  11. Enzyme-Regulated Supramolecular Assemblies of Cholesterol Conjugates against Drug-Resistant Ovarian Cancer Cells.

    Science.gov (United States)

    Wang, Huaimin; Feng, Zhaoqianqi; Wu, Dongdong; Fritzsching, Keith J; Rigney, Mike; Zhou, Jie; Jiang, Yujie; Schmidt-Rohr, Klaus; Xu, Bing

    2016-08-31

    We report that phosphotyrosine-cholesterol conjugates effectively and selectively kill cancer cells, including platinum-resistant ovarian cancer cells. The conjugate increases the degree of noncovalent oligomerization upon enzymatic dephosphorylation in aqueous buffer. This enzymatic conversion also results in the assembly of the cholesterol conjugates inside and outside cells and leads to cell death. Preliminary mechanistic studies suggest that the formed assemblies of the conjugates not only interact with actin filaments and microtubules but also affect lipid rafts. As the first report of multifaceted supramolecular assemblies of cholesterol conjugates against cancer cells, this work illustrates the integration of enzyme catalysis and self-assembly of essential biological small molecules on and inside cancer cells as a promising strategy for developing multifunctional therapeutics to treat drug-resistant cancers. PMID:27529637

  12. Generation of Supramolecular Chirality around Twofold Rotational or Helical Axes in Crystalline Assemblies of Achiral Components

    Directory of Open Access Journals (Sweden)

    Mikiji Miyata

    2015-10-01

    Full Text Available A multi-point approximation method clarifies supramolecular chirality of twofold rotational or helical assemblies as well as bundles of the one-dimensional (1D assemblies. While one-point approximation of materials claims no chirality generation of such assemblies, multi-point approximations do claim possible generation in the 1D assemblies of bars and plates. Such chirality derives from deformations toward three-axial directions around the helical axes. The chiral columns are bundled in chiral ways through symmetry operations. The preferable right- or left-handed columns are bundled together to yield chiral crystals with right- or left-handedness, respectively, indicating that twofold helix symmetry operations cause chiral crystals composed of achiral components via a three-stepwise and three-directional process.

  13. Cooperative Self-Assembly Transfer from Hierarchical Supramolecular Polymers to Gold Nanoparticles.

    Science.gov (United States)

    Coelho, João Paulo; Tardajos, Gloria; Stepanenko, Vladimir; Rödle, Alexander; Fernández, Gustavo; Guerrero-Martínez, Andrés

    2015-11-24

    The transfer of information encoded by molecular subcomponents is a key phenomenon that regulates the biological inheritance in living organisms, yet there is a lack of understanding of related transfer mechanisms at the supramolecular level in artificial multicomponent systems. Our contribution to tackle this challenge has focused on the design of a thiolated π-conjugated linking unit, whose hierarchical, cooperative self-assembly in nonpolar media can be efficiently transferred from the molecular to the nanoscopic level, thereby enabling the reversible self-assembly of gold nanoparticle (AuNP) clusters. The transfer of supramolecular information by the linking π-system can only take place when a specific cooperative nucleation-elongation mechanism is operative, whereas low-ordered noncooperative assemblies formed below a critical concentration do not suffice to extend the order to the AuNP level. To the best of our knowledge, our approach has allowed for the first time a deep analysis of the hierarchy levels and thermodynamics involved in the self-assembly of AuNPs.

  14. Hyaluronic Acid-Based Biocompatible Supramolecular Assembly for Sustained Release of Antiretroviral Drug.

    Science.gov (United States)

    Song, Byeongwoon; Puskás, István; Szente, Lajos; Hildreth, James E K

    2016-09-01

    Human immunodeficiency virus (HIV) infection and its associated diseases continue to increase despite the progress in our understanding of HIV biology and the availability of a number of antiretroviral drugs. Adherence is a significant factor in the success of HIV therapy and current HIV treatment regimens require a combination of antiviral drugs to be taken at least daily for the remainder of a patient's life. A drug delivery system that allows sustained drug delivery could reduce the medical burden and costs associated with medication nonadherence. Here, we describe a novel supramolecular assembly or matrix that contains an anionic polymer hyaluronic acid, cationic polymer poly-l-lysine, and anionic oligosaccharide sulfobutylether-beta-cyclodextrin. HIV reverse transcriptase inhibitors Zidovudine and Lamivudine were successfully encapsulated into the polymer assembly in a noncovalent manner. The physicochemical properties and antiviral activity of the polymer assemblies were studied. The results of this study suggest that the supramolecular assemblies loaded with HIV drugs exert potent antiviral activity and allow sustained drug release. A novel drug delivery formulation such as the one described here could facilitate our efforts to reduce the morbidity and mortality associated with HIV infections and could be utilized in the design of therapeutic approaches for other diseases. PMID:26975245

  15. Molecular self-assembly approaches for supramolecular electronic and organic electronic devices

    Science.gov (United States)

    Yip, Hin-Lap

    Molecular self-assembly represents an efficient bottom-up strategy to generate structurally well-defined aggregates of semiconducting pi-conjugated materials. The capability of tuning the chemical structures, intermolecular interactions and nanostructures through molecular engineering and novel materials processing renders it possible to tailor a large number of unprecedented properties such as charge transport, energy transfer and light harvesting. This approach does not only benefit traditional electronic devices based on bulk materials, but also generate a new research area so called "supramolecular electronics" in which electronic devices are built up with individual supramolecular nanostructures with size in the sub-hundred nanometers range. My work combined molecular self-assembly together with several novel materials processing techniques to control the nucleation and growth of organic semiconducting nanostructures from different type of pi-conjugated materials. By tailoring the interactions between the molecules using hydrogen bonds and pi-pi stacking, semiconducting nanoplatelets and nanowires with tunable sizes can be fabricated in solution. These supramolecular nanostructures were further patterned and aligned on solid substrates through printing and chemical templating methods. The capability to control the different hierarchies of organization on surface provides an important platform to study their structural-induced electronic properties. In addition to using molecular self-assembly to create different organic nanostructures, functional self-assembled monolayer (SAM) formed by spontaneous chemisorption on surfaces was used to tune the interfacial property in organic solar cells. Devices showed dramatically improved performance when appropriate SAMs were applied to optimize the contact property for efficiency charge collection.

  16. Structural Consequences of Anionic Host-Cationic Guest Interactions in a Supramolecular Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Johnson, Darren W.; Szigethy, Geza; Davis, Anna V.; Teat, Simon J.; Oliver, Allen G.; Bergman, Robert G.; Raymond, Kenneth N.

    2008-07-09

    The molecular structure of the self-assembled supramolecular assembly [M{sub 4}L{sub 6}]{sup 12-} has been explored with different metals (M = Ga{sup III}, Fe{sup III}, Ti{sup IV}) and different encapsulated guests (NEt{sub 4}{sup +}, BnNMe{sub 3}{sup +}, Cp{sub 2}Co{sup +}, Cp*{sub 2}Co{sup +}) by X-ray crystallography. While the identity of the metal ions at the vertices of the M{sub 4}L{sub 6} structure is found to have little effect on the assembly structure, encapsulated guests significantly distort the size and shape of the interior cavity of the assembly. Cations on the exterior of the assembly are found to interact with the assembly through either {pi}-{pi}, cation-{pi}, or CH-{pi} interactions. In some cases, the exterior guests interact with only one assembly, but cations with the ability to form multiple {pi}-{pi} interactions are able to interact with adjacent assemblies in the crystal lattice. The solvent accessible cavity of the assembly is modeled using the rolling probe method and found to range from 253-434 {angstrom}{sup 3}, depending on the encapsulated guest. Based on the volume of the guest and the volume of the cavity, the packing coefficient for each host-guest complex is found to range from 0.47-0.67.

  17. Synergy in supramolecular chemistry

    CERN Document Server

    Nabeshima, Tatsuya

    2014-01-01

    Synergy and Cooperativity in Multi-metal Supramolecular Systems, T. NabeshimaHierarchically Assembled Titanium Helicates, Markus AlbrechtSupramolecular Hosts and Catalysts Formed by Self-assembly of Multinuclear Zinc Complexes in Aqueous Solution, Shin AokiSupramolecular Assemblies Based on Interionic Interactions, H. MaedaSupramolecular Synergy in the Formation and Function of Guanosine Quadruplexes, Jeffery T. DavisOn-Surface Chirality in Porous Self-Assembled Monolayers at Liquid-Solid Interface, Kazukuni Tahar

  18. Supramolecular nanoparticles generated by the self-assembly of polyrotaxanes for antitumor drug delivery

    Directory of Open Access Journals (Sweden)

    Liu R

    2012-10-01

    Full Text Available Rong Liu,1,2,* Yusi Lai,1,* Bin He,1 Yuan Li,1 Gang Wang,1 Shuang Chang,1 Zhongwei Gu1 1National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China; 2Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China*These authors contributed equally to this paperAbstract: A new approach of fabricating supramolecular nanoparticles generated by self-assembly polyrotaxanes for antitumor drug delivery has been reported. Cinnamic-acid-modified poly(ethylene glycol chains were threaded in a-cyclodextrins to form polyrotaxanes. The polyrotaxanes self-assembled supramolecular nanoparticles. The morphology of the nanoparticles was changed from nanovesicle to micelle after the antitumor drug, doxorubicin, was loaded. The release profile of the drug-loaded nanoparticles was investigated, and it was found that the sustaining release time could last for 32 hours. The drug-loaded nanoparticles were co-cultured with mouse 4T1 breast cancer cells with a drug concentration of 10 µg/mL; the cell survival rate was 3.3% after a 72-hour incubation. In an in vivo study of breast cancer in a mouse model, the drug-loaded nanoparticles were injected in the tail veins of mice with a dose of 5 mg/kg body weight. The tumor inhibition rate of drug-loaded nanoparticles was 53%, which was better than that of doxorubicin hydrochloride. The cardiac toxicity of doxorubicin was decreased greatly after the encapsulation into supramolecular polyrotaxane nanoparticles.Keywords: polyrotaxane, self-assembly, nanoparticle, doxorubicin, supermolecular

  19. Mechanism of N-octadecyl-N'-maleoyl-L-phenylalanine self-assembled into supramolecular structures

    Institute of Scientific and Technical Information of China (English)

    Sheng Zu Zhang; Xin Jian Fu; Hong Wang; Ya Jiang Yang

    2008-01-01

    N-Octadecyl-N'-maleoyl-L-phenylalanine (ODMA-L-Phe) was synthesized through the condensation, deprotection and aeid-ylation reaction of BOC-L-phenylalanine, octadecylamine and maleic anhydride. ODMA-L-Phe can self-assemble in some organic solvents and turned them into thermally reversible physical supramolecular organogels. The morphology of ODMA-L-Phe aggregates was characterized by polarized optical microscopy (POM) and field emission scanning electron microscope (FE-SEM). The aggregates of ODMA-L-Phe were needle-like fibrils with diameters of approximately 100-200 nm. The mechanism of ODMA-L-Phe self-assembly in organic solvents was investigated using 1H NMR and circular dichroism (CD). The results indicated that hydrogen bonding was one of the main driving forces for the self-assembly of ODMA-L-Phe.

  20. The Acid Hydrolysis Mechanism of Acetals Catalyzed by a Supramolecular Assembly in Basic Solution

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2008-09-24

    A self-assembled supramolecular host catalyzes the hydrolysis of acetals in basic aqueous solution. The mechanism of hydrolysis is consistent with the Michaelis-Menten kinetic model. Further investigation of the rate limiting step of the reaction revealed a negative entropy of activation ({Delta}S{double_dagger} = -9 cal mol{sup -1}K{sup -1}) and an inverse solvent isotope effect (k(H{sub 2}O)/k(D{sub 2}O) = 0.62). These data suggest that the mechanism of hydrolysis that takes place inside the assembly proceeds through an A-2 mechanism, in contrast to the A-1 mechanism operating in the uncatalyzed reaction. Comparison of the rates of acetal hydrolysis in the assembly with the rate of the reaction of unencapsulated substrates reveals rate accelerations of up to 980 over the background reaction for the substrate diethoxymethane.

  1. Dynamic Characterization of Crystalline Supramolecular Rotors Assembled through Halogen Bonding.

    Science.gov (United States)

    Catalano, Luca; Pérez-Estrada, Salvador; Terraneo, Giancarlo; Pilati, Tullio; Resnati, Giuseppe; Metrangolo, Pierangelo; Garcia-Garibay, Miguel A

    2015-12-16

    A modular molecular kit for the preparation of crystalline molecular rotors was devised from a set of stators and rotators to gain simple access to a large number of structures with different dynamic performance and physical properties. In this work, we have accomplished this with crystalline molecular rotors self-assembled by halogen bonding of diazabicyclo[2.2.2]octane, acting as a rotator, and a set of five fluorine-substituted iodobenzenes that take the role of the stator. Using variable-temperature (1)H T1 spin-lattice relaxation measurements, we have shown that all structures display ultrafast Brownian rotation with activation energies of 2.4-4.9 kcal/mol and pre-exponential factors of the order of (1-9) × 10(12) s(-1). Line shape analysis of quadrupolar echo (2)H NMR measurements in selected examples indicated rotational trajectories consistent with the 3-fold or 6-fold symmetric potential of the rotator. PMID:26583701

  2. Complexation-induced supramolecular assembly drives metal-ion extraction.

    Science.gov (United States)

    Ellis, Ross J; Meridiano, Yannick; Muller, Julie; Berthon, Laurence; Guilbaud, Philippe; Zorz, Nicole; Antonio, Mark R; Demars, Thomas; Zemb, Thomas

    2014-09-26

    Combining experiment with theory reveals the role of self-assembly and complexation in metal-ion transfer through the water-oil interface. The coordinating metal salt Eu(NO3)3 was extracted from water into oil by a lipophilic neutral amphiphile. Molecular dynamics simulations were coupled to experimental spectroscopic and X-ray scattering techniques to investigate how local coordination interactions between the metal ion and ligands in the organic phase combine with long-range interactions to produce spontaneous changes in the solvent microstructure. Extraction of the Eu(3+)-3(NO3(-)) ion pairs involves incorporation of the "hard" metal complex into the core of "soft" aggregates. This seeds the formation of reverse micelles that draw the water and "free" amphiphile into nanoscale hydrophilic domains. The reverse micelles interact through attractive van der Waals interactions and coalesce into rod-shaped polynuclear Eu(III) -containing aggregates with metal centers bridged by nitrate. These preorganized hydrophilic domains, containing high densities of O-donor ligands and anions, provide improved Eu(III) solvation environments that help drive interfacial transfer, as is reflected by the increasing Eu(III) partitioning ratios (oil/aqueous) despite the organic phase approaching saturation. For the first time, this multiscale approach links metal-ion coordination with nanoscale structure to reveal the free-energy balance that drives the phase transfer of neutral metal salts. PMID:25169678

  3. Assembly of supramolecular nanotubes from molecular triangles and 1,2-dihalohydrocarbons.

    Science.gov (United States)

    Liu, Zhichang; Liu, Guoliang; Wu, Yilei; Cao, Dennis; Sun, Junling; Schneebeli, Severin T; Nassar, Majed S; Mirkin, Chad A; Stoddart, J Fraser

    2014-11-26

    Precise control of molecular assembly is a challenging goal facing supramolecular chemists. Herein, we report the highly specific assembly of a range of supramolecular nanotubes from the enantiomeric triangular naphthalenediimide-based macrocycles (RRRRRR)- and (SSSSSS)-NDI-Δ and a class of similar solvents, namely, the 1,2-dihalo-ethanes and -ethenes (DXEs). Three kinds of supramolecular nanotubes are formed from the columnar stacking of NDI-Δ units with a 60° mutual rotation angle as a result of cooperative [C-H···O] interactions, directing interactions of the [X···X]-bonded DXE chains inside the nanotubes and lateral [X···π] or [π···π] interactions. They include (i) semiflexible infinite nanotubes formed in the gel state from NDI-Δ and (E)-1,2-dichloroethene, (ii) rigid infinite nonhelical nanotubes produced in the solid state from NDI-Δ and BrCH2CH2Br, ClCH2CH2Br, and ClCH2CH2I, and (iii) a pair of rigid tetrameric, enantiomeric single-handed (P)- and (M)-helical nanotubes formed in the solid state from the corresponding (RRRRRR)- and (SSSSSS)-NDI-Δ with ClCH2CH2Cl. In case (i), only the electron-rich C═C double bond of (E)-1,2-dichloroethene facilitates the gelation of NDI-Δ. In cases (ii) and (iii), the lengths of anti-DXEs determine the translation of the chirality of NDI-Δ into the helicity of nanotubes. Only ClCH2CH2Cl induces single-handed helicity into the nanotubes. The subtle interplay of noncovalent bonding interactions, resulting from the tiny structural variations involving the DXE guests, is responsible for the diverse and highly specific assembly of NDI-Δ. This research highlights the critical role that guests play in constructing assembled superstructures of hosts and offers a novel approach to creating supramolecular nanotubes. PMID:25357152

  4. Self-assembled fibrillar networks of a multifaceted chiral squaramide: supramolecular multistimuli-responsive alcogels.

    Science.gov (United States)

    Schiller, Jana; Alegre-Requena, Juan V; Marqués-López, Eugenia; Herrera, Raquel P; Casanovas, Jordi; Alemán, Carlos; Díaz Díaz, David

    2016-05-11

    Chiral N,N'-disubstituted squaramide has been found to undergo self-assembly in a variety of alcoholic solvents at low concentrations leading to the formation of novel nanostructured supramolecular alcogels. The gels responded to thermal, mechanical, optical and chemical stimuli. Solubility studies, gelation ability tests and computer modeling of a series of structurally related squaramides proved the existence of a unique combination of non-covalent molecular interactions and favorable hydrophobic/hydrophilic balance in that drive the anisotropic growth of alcogel networks. The results have also revealed a remarkable effect of ultrasound on both the gelation kinetics and the properties of the alcogels. PMID:27087352

  5. Self-assembly behavior of a linear-star supramolecular amphiphile based on host-guest complexation.

    Science.gov (United States)

    Wang, Juan; Wang, Xing; Yang, Fei; Shen, Hong; You, Yezi; Wu, Decheng

    2014-11-01

    A star polymer, β-cyclodextrin-poly(l-lactide) (β-CD-PLLA), and a linear polymer, azobenzene-poly(ethylene glycol) (Azo-PEG), could self-assemble into a supramolecular amphiphilic copolymer (β-CD-PLLA@Azo-PEG) based on the host-guest interaction between β-CD and azobenzene moieties. This linear-star supramolecular amphiphilic copolymer further self-assembled into a variety of morphologies, including sphere-like micelle, carambola-like micelle, naan-like micelle, shuttle-like lamellae, tube-like fiber, and random curled-up lamellae, by tuning the length of hydrophilic or hydrophobic chains. The variation of morphology was closely related to the topological structure and block ratio of the supramolecular amphiphiles. These self-assembly structures could disassemble upon an ultraviolet (UV) light irradiation. PMID:25310380

  6. A Dynamic Combinatorial Approach for Identifying Side Groups that Stabilize DNA-Templated Supramolecular Self-Assemblies

    Directory of Open Access Journals (Sweden)

    Delphine Paolantoni

    2015-02-01

    Full Text Available DNA-templated self-assembly is an emerging strategy for generating functional supramolecular systems, which requires the identification of potent multi-point binding ligands. In this line, we recently showed that bis-functionalized guanidinium compounds can interact with ssDNA and generate a supramolecular complex through the recognition of the phosphodiester backbone of DNA. In order to probe the importance of secondary interactions and to identify side groups that stabilize these DNA-templated self-assemblies, we report herein the implementation of a dynamic combinatorial approach. We used an in situ fragment assembly process based on reductive amination and tested various side groups, including amino acids. The results reveal that aromatic and cationic side groups participate in secondary supramolecular interactions that stabilize the complexes formed with ssDNA.

  7. Phase diagram of a model of the protein amelogenin

    Science.gov (United States)

    Haaga, Jason; Pemberton, Elizabeth; Gunton, J. D.; Rickman, J. M.

    2016-08-01

    There has been considerable recent interest in the self-assembly and phase behavior of models of colloidal and protein particles with anisotropic interactions. One example of particular interest is amelogenin, an important protein involved in the formation of dental enamel. Amelogenin is primarily hydrophobic with a 25-residue charged C-terminus tail. This protein undergoes a hierarchical assembly process that is crucial to mineral deposition, and experimental work has demonstrated that the deletion of the C-terminus tail prevents this self-assembly. A simplified model of amelogenin has been proposed in which the protein is treated as a hydrophobic sphere, interacting via the Asakura-Oosawa (AO) potential, with a tethered point charge on its surface. In this paper, we examine the effect of the Coulomb interaction between the point charges in altering the phase diagram of the AO model. For the parameter case specific to amelogenin, we find that the previous in vitro experimental and model conditions correspond to the system being near the low-density edge of the metastable region of the phase diagram. Our study illustrates more generally the importance of understanding the phase diagram for proteins, in that the kinetic pathway for self-assembly and the resulting aggregate morphology depends on the location of the initial state in the phase diagram.

  8. Creating Prebiotic Sanctuary: Self-Assembling Supramolecular Peptide Structures Bind and Stabilize RNA

    Science.gov (United States)

    Carny, Ohad; Gazit, Ehud

    2011-04-01

    Any attempt to uncover the origins of life must tackle the known `blind watchmaker problem'. That is to demonstrate the likelihood of the emergence of a prebiotic system simple enough to be formed spontaneously and yet complex enough to allow natural selection that will lead to Darwinistic evolution. Studies of short aromatic peptides revealed their ability to self-assemble into ordered and stable structures. The unique physical and chemical characteristics of these peptide assemblies point out to their possible role in the origins of life. We have explored mechanisms by which self-assembling short peptides and RNA fragments could interact together and go through a molecular co-evolution, using diphenylalanine supramolecular assemblies as a model system. The spontaneous formation of these self-assembling peptides under prebiotic conditions, through the salt-induced peptide formation (SIPF) pathway was demonstrated. These peptide assemblies possess the ability to bind and stabilize ribonucleotides in a sequence-depended manner, thus increase their relative fitness. The formation of these peptide assemblies is dependent on the homochirality of the peptide monomers: while homochiral peptides (L-Phe-L-Phe and D-Phe-D-Phe) self-assemble rapidly in aqueous environment, heterochiral diastereoisomers (L-Phe-D-Phe and D-Phe-L-Phe) do not tend to self-assemble. This characteristic consists with the homochirality of all living matter. Finally, based on these findings, we propose a model for the role of short self-assembling peptides in the prebiotic molecular evolution and the origin of life.

  9. Supramolecular Assembly of an Evolved Miniprotein Host and Fluorogenic Guest Pair.

    Science.gov (United States)

    Xu, Bi; Zhou, Xinqi; Stains, Cliff I

    2015-11-18

    Small-molecule-induced assembly of defined protein structures could have broad implications for the fabrication of new materials as well as biological signaling pathways. However, the design of new host-guest pairs capable of small-molecule-induced assembly in a biologically relevant context remains a significant challenge. Herein, we report a series of miniprotein hosts, evolved from the tenth type III domain of fibronectin (Fn3), that display remarkable binding affinity toward a red-shifted environment-sensitive merocyanine derivative, termed sI-Pht. Importantly, the consensus binder isolated from directed evolution experiments (6.2.18) forms a higher order assembly in response to addition of sI-Pht, as assessed by analytical ultracentrifugation. sI-Pht-induced assembly of 6.2.18 results in a 570-fold increase in fluorescence compared to free dye. This property enables the direct visualization of host-guest assemblies by fluorescence microscopy. As a demonstration, we show that supramolecular assembly of the 6.2.18-sI-Pht system can be visualized on the surface of living yeast cells. This new host-guest pair provides a tool for the potential development of new materials as well as pathway engineering. In a broader context, this work details a new design paradigm for the discovery of host-guest systems that function in the context of living cells. PMID:26523606

  10. In situ clicking methylglyoxal for hierarchical self-assembly of nanotubes in supramolecular hydrogel.

    Science.gov (United States)

    Liu, Shuang; Luo, Yufeng; Liang, Gaolin

    2016-01-14

    Methylglyoxal (MGO) is a toxic, dicarbonyl metabolite in all living cells and its detoxification is regulated by glyoxalase I (GLOI). Herein, we rationally designed a precursor o-phenylenediamine-Phe-Phe-OH (1) which “click” reacts with MGO to yield amphiphilic methylquinoxaline-Phe-Phe-OH (2) to self-assemble into supramolecular hydrogel II (Gel II). Cryo-TEM images of Gel II suggested that there existed two orders of self-assembly to form the 32.8 nm width-nanotubes in the hydrogel. The hypothesis was validated with the analyses of the fluorescence, transmittance, and circular dichroism data of the serial dilutions of Gel II. Interference tests indicated that hydrogelation of 1 with MGO would not be affected by nitric oxide (NO). Our results suggest that 1 could be applied for specific hydrogelation with MGO, and potentially the removal of MGO in vitro. PMID:26660853

  11. Self-assembled sorbitol-derived supramolecular hydrogels for the controlled encapsulation and release of active pharmaceutical ingredients.

    Science.gov (United States)

    Howe, Edward J; Okesola, Babatunde O; Smith, David K

    2015-05-01

    A simple supramolecular hydrogel based on 1,3:2,4-di(4-acylhydrazide)benzylidene sorbitol (DBS-CONHNH2), is able to extract acid-functionalised anti-inflammatory drugs via directed interactions with the self-assembled gel nanofibres. Two-component hydrogel-drug hybrid materials can be easily formed by mixing and exhibit pH-controlled drug release.

  12. Giant, Hollow 2D Metalloarchitecture: Stepwise Self-Assembly of a Hexagonal Supramolecular Nut.

    Science.gov (United States)

    Li, Yiming; Jiang, Zhilong; Wang, Ming; Yuan, Jie; Liu, Die; Yang, Xiaoyu; Chen, Mingzhao; Yan, Jun; Li, Xiaopeng; Wang, Pingshan

    2016-08-10

    A polyterpyridinyl building block-based nutlike hexagonal bismetallo architecture with a central hollow Star of David was assembled by a stepwise strategy. This nanoarchitecture can be viewed as a recursive mathematical form that possesses a supramolecular corner-connected cyclic structure, i.e., a triangle or rhombus at various levels of scale or detail. The key metallo-organic ligand (MOL) with four uncomplexed free terpyridines was obtained by a final Suzuki cross-coupling reaction with a tetrabromoterpyridine Ru dimer. The molecular metallorhombus was prepared by reacting the MOL with a 60° bis-terpyridine and Fe(2+). The giant hollow hexagonal nut with a diameter of more than 11 nm and a molecular weight of ca. 33 kDa was obtained in near-quantitative yield by mixing the two types of multi-terpyridine ligands with Fe(2+). The supramolecular architecture was characterized by NMR ((1)H and (13)C), 2D NMR (COSY and ROESY), and DOSY spectroscopies, high-resolution electrospray ionization mass spectrometry, traveling-wave ion mobility mass spectrometry, and transmission electron microscopy. PMID:27447878

  13. Encapsulation and characterization of proton-bound amine homodimers in a water-soluble, self-assembled supramolecular host

    OpenAIRE

    Pluth, Michael D.; Fiedler, Dorothea; Mugridge, Jeffrey S.; Bergman, Robert G.; Raymond, Kenneth N.

    2009-01-01

    Cyclic amines can be encapsulated in a water-soluble self-assembled supramolecular host upon protonation. The hydrogen-bonding ability of the cyclic amines, as well as the reduced degrees of rotational freedom, allows for the formation of proton-bound homodimers inside of the assembly that are otherwise not observable in aqueous solution. The generality of homodimer formation was explored with small N-alkyl aziridines, azetidines, pyrrolidines, and piperidines. Proton-bound homodimer formatio...

  14. Control over Structure and Function of Peptide Amphiphile Supramolecular Assemblies through Molecular Design and Energy Landscapes

    Science.gov (United States)

    Tantakitti, Faifan

    Supramolecular chemistry is a powerful tool to create a material of a defined structure with tunable properties. This strategy has led to catalytically active, bioactive, and environment-responsive materials, among others, that are valuable in applications ranging from sensor technology to energy and medicine. Supramolecular polymers formed by peptide amphiphiles (PAs) have been especially relevant in tissue regeneration due to their ability to form biocompatible structures and mimic many important signaling molecules in biology. These supramolecular polymers can form nanofibers that create networks which mimic natural extracellular matrices. PA materials have been shown to induce growth of blood vessels, bone, cartilage, and nervous tissue, among others. The work described in this thesis not only studied the relationship between molecular structure and functions of PA assemblies, but also uncovered a powerful link between the energy landscape of their supramolecular self-assembly and the ability of PA materials to interact with cells. In chapter 2, it is argued that fabricating fibrous nanostructures with defined mechanical properties and decoration with bioactive molecules is not sufficient to create a material that can effectively communicate with cells. By systemically placing the fibronectin-derived RGDS epitope at increasing distances from the surface of PA nanofibers through a linker of one to five glycine residues, integrin-mediated RGDS signaling was enhanced. The results suggested that the spatial presentation of an epitope on PA nanofibers strongly influences the bioactivity of the PA substrates. In further improving functionality of a PA-based scaffold to effectively direct cell growth and differentiation, chapter 3 explored the use of a cell microcarrier to compartmentalize and simultaneously tune insoluble and soluble signals in a single matrix. PA nanofibers were incorporated at the surface of the microcarrier in order to promote cell adhesion, while

  15. Acceleration of Amide Bond Rotation by Encapsulation in the Hydrophobic Interior of a Water-Soluble Supramolecular Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2008-04-08

    The hydrophobic interior cavity of a self-assembled supramolecular assembly exploits the hydrophobic effect for the encapsulation of tertiary amides. Variable temperature 1H NMR experiments reveal that the free energy barrier for rotation around the C-N amide bond is lowered by up to 3.6 kcal/mol upon encapsulation. The hydrophobic cavity of the assembly is able to stabilize the less polar transition state of the amide rotation process. Carbon-13 labeling studies showed that the {sup 13}C NMR carbonyl resonance increases with temperature for the encapsulated amides which suggests that the assembly is able to favor a twisted for of the amide.

  16. Proton Mediated Chemistry and Catalysis in a Self-Assembled Supramolecular Host

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2009-04-10

    Synthetic supramolecular host assemblies can impart unique reactivity to encapsulated guest molecules. Synthetic host molecules have been developed to carry out complex reactions within their cavities, despite the fact that they lack the type of specifically tailored functional groups normally located in the analogous active sites of enzymes. Over the past decade, the Raymond group has developed a series of self-assembled supramolecules and the Bergman group has developed and studied a number of catalytic transformations. In this Account, we detail recent collaborative work between these two groups, focusing on chemical catalysis stemming from the encapsulation of protonated guests and expanding to acid catalysis in basic solution. We initially investigated the ability of a water-soluble, self-assembled supramolecular host molecule to encapsulate protonated guests in its hydrophobic core. Our study of encapsulated protonated amines revealed rich host-guest chemistry. We established that self-exchange (that is, in-out guest movement) rates of protonated amines were dependent on the steric bulk of the amine rather than its basicity. The host molecule has purely rotational tetrahedral (T) symmetry, so guests with geminal N-methyl groups (and their attendant mirror plane) were effectively desymmetrized; this allowed for the observation and quantification of the barriers for nitrogen inversion followed by bond rotation. Furthermore, small nitrogen heterocycles, such as N-alkylaziridines, N-alkylazetidines, and N-alkylpyrrolidines, were found to be encapsulated as proton-bound homodimers or homotrimers. We further investigated the thermodynamic stabilization of protonated amines, showing that encapsulation makes the amines more basic in the cavity. Encapsulation raises the effective basicity of protonated amines by up to 4.5 pK{sub a} units, a difference almost as large as that between the moderate and strong bases carbonate and hydroxide. The thermodynamic stabilization

  17. Proton-Mediated Chemistry and Catalysis in a Self-Assembled Supramolecular Host

    International Nuclear Information System (INIS)

    Synthetic supramolecular host assemblies can impart unique reactivity to encapsulated guest molecules. Synthetic host molecules have been developed to carry out complex reactions within their cavities, despite the fact that they lack the type of specifically tailored functional groups normally located in the analogous active sites of enzymes. Over the past decade, the Raymond group has developed a series of self-assembled supramolecules and the Bergman group has developed and studied a number of catalytic transformations. In this Account, we detail recent collaborative work between these two groups, focusing on chemical catalysis stemming from the encapsulation of protonated guests and expanding to acid catalysis in basic solution. We initially investigated the ability of a water-soluble, self-assembled supramolecular host molecule to encapsulate protonated guests in its hydrophobic core. Our study of encapsulated protonated amines revealed rich host-guest chemistry. We established that self-exchange (that is, in-out guest movement) rates of protonated amines were dependent on the steric bulk of the amine rather than its basicity. The host molecule has purely rotational tetrahedral (T) symmetry, so guests with geminal N-methyl groups (and their attendant mirror plane) were effectively desymmetrized; this allowed for the observation and quantification of the barriers for nitrogen inversion followed by bond rotation. Furthermore, small nitrogen heterocycles, such as N-alkylaziridines, N-alkylazetidines, and N-alkylpyrrolidines, were found to be encapsulated as proton-bound homodimers or homotrimers. We further investigated the thermodynamic stabilization of protonated amines, showing that encapsulation makes the amines more basic in the cavity. Encapsulation raises the effective basicity of protonated amines by up to 4.5 pKa units, a difference almost as large as that between the moderate and strong bases carbonate and hydroxide. The thermodynamic stabilization of

  18. Competitive Self-Assembly Manifests Supramolecular Darwinism in Soft-Oxometalates

    Science.gov (United States)

    Das, Santu; Kumar, Saurabh; Mallick, Apabrita; Roy, Soumyajit

    2015-09-01

    Topological transformation manifested in inorganic materials shows manifold possibilities. In our present work, we show a clear topological transformation in a soft-oxometalate (SOM) system which was formed from its polyoxometalate (POM) precursor [PMo12@Mo72Fe30]. This topological transformation was observed due to time dependent competitive self-assembly of two different length scale soft-oxometalate moieties formed from this two-component host-guest reaction. We characterized different morphologies by scanning electron microscopy, electron dispersive scattering spectroscopy, dynamic light scattering, horizontal attenuated total reflection-infrared spectroscopy and Raman spectroscopy. The predominant structure is selected by its size in a sort of supramolecular Darwinian competition in this process and is described here.

  19. The assembly and structure of self-assembling peptides: molecular to supramolecular

    OpenAIRE

    Morris, Kyle

    2012-01-01

    Self-assembling molecules are central to a plethora of processes found in nature, biotechnology and even disease. The importance of the non-covalent interaction of monomers to the formation of fibrillar assemblies is evident in the repeated use of this mechanism throughout nature, from essential cellular processes such as the formation of the cytoskeleton to the production of silk. Further, it has been recognised in the last two decades that a self-assembly mechanism, that is t...

  20. Study on the α-cyclodextrin/poly(ethylene glycol) self-assembly supramolecular nanoparticles for drug delivery

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper reports the synthesis and drug delivery properties of a novel supramolecular nanoparticle.α-Cyclodextrins(α-CD) were threaded on cinnamic acid modified poly(ethylene glycol) to form inclusion complex nanoparticles by supramolecular self-assemble.The anti-tumor drug doxorubicin was loaded in the nanoparticles and released in vitro to study the drug release behavior and the anti-tumor effects.The structure and morphology of the nanoparticles were characterized by nuclear magnetic resonance,X-ray diffraction,ultraviolet absorbance,dynamic laser scattering,scanning electronic microscopy,transmission electron microscopy and atom force microscopy.The distribution of the drug loaded nanoparticles in cells and the anti-tumor effects were studied by confocal laser microscopy.The results demonstrate that the supramolecular nanoparticle is biocompatible and it is a promising carrier for drug delivery systems.

  1. Sensitization effects of supramolecular assemblies on the luminescence of terbium-ion prulifloxacin complexes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hong; Yi Chongyue; Li Xue; Fang Fang [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yang Yajiang, E-mail: yjyang@mail.hust.edu.c [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-04-15

    Luminescence enhancement of terbium-ion prulifloxacin complexes (Tb(III)-PUFX) in supramolecular hydrogels formed by assembly of 1,3:2,4-di-O-benzylidene-D-sorbitol (DBS) was investigated by steady-state fluorescence, varying temperature fluorescence and time-resolved fluorescence. The luminescence images show that Tb(III)-PUFX were dispersed in the DBS gels. The luminescence intensity of Tb(III)-PUFX in the DBS gels was significantly increased in comparison with that in corresponding aqueous solutions. The varying temperature fluorescent spectra show that the luminescence intensity of Tb(III)-PUFX decreased with an increase in the temperature. This implies that the luminescence enhancement of Tb(III)-PUFX is related to the dissociation and the formation of the DBS assemblies. Time-resolved fluorescence measurements show slower rotational motion in DBS gels in comparison with that in the corresponding aqueous solutions. This may be ascribed to a unique microstructure of three-dimensional network formed by DBC aggregates, resulting in deactivation of the nonradiative relaxation. The images of field emission scanning electron microscopy and polarized optical microscopy indicate that the morphology of the DBS assemblies was not influenced upon addition of Tb(III)-PUFX to the DBS gels.

  2. Exploration of supramolecular assemblies of rac-1,3-cyclohexanedicarboxylic acid

    Science.gov (United States)

    Giri, Lopamudra; Pedireddi, V. R.

    2015-11-01

    Supramolecular assemblies of rac-1,3-cyclohexanedicarboxylic acid (1) with melamine (a), 1,2-bis(4-pyridyl)ethene (b); 1, 2-bis(4pyridyl)ethane (c) in the presence of Co(II), and 1,10-phenanthroline (d) along with Cu(II) and Ni(II), respectively 1a - 1d and 1d', have been reported. All the assemblies were prepared by crystallization method, through slow-evaporation process, at ambient conditions. All the complexes yield sheet structures that are stacked in three-dimensional arrangement, however, each structure is unique within three-dimensional networks with varied arrangements of either organic entities or coordinated ensembles. For instance, while a host-guest type assembly was observed in 1a, only crinkled tapes are observed in 1b. Among coordination complexes, 1c has an interpenetrated cubic network, whereas 1d and 1d' form host-guest networks. A noteworthy feature to highlight is that the water molecules in the channels of 1d organize in the form of pentamers, which are further held together through tetrameric network, with the aid of hydrogen bonds. A further interesting feature is the presence of acid 1 in different conformations in the complexes as cis form in 1b, 1c and 1d and trans form in 1d'. However, in 1a both cis and trans conformers are observed.

  3. Supramolecular assemblies of 4,7-phenanthroline with various aromatic polycarboxylic acids

    Science.gov (United States)

    Biswas, Sharmita Nandy; Nandy, Purnendu

    2016-10-01

    Five molecular complexes 1a-1e, of 4,7-phenanthroline (1) with various aromatic polycarboxylic acids such as benzene-1,3-dicarboxylic acid (a), pyridine-2,6-dicarboxylic acid (b), pyridine-2,5-dicarboxylic acid (c), benzene-1,2,3,4,5-pentacarboxylic acid (d) and 1,2,3,4,5,6-benzenehexacarboxylic acid (e) have been prepared and characterized by single crystal X-ray diffraction and thermogravimetric analyses. The analysis shows that all the assemblies crystallized as hydrates, except complex, 1c, formed between 1 and pyridine-2,5-dicarboxylic acid. Single crystal X-ray data reveals that the packing patterns of all the molecular complexes have been directed by strong hydrogen bonding O-H⋯O/O-H⋯N/N+-H⋯O- and weak hydrogen bonding C-H⋯O interactions. All the hydrated assemblies aggregate through the formation of cyclic networks as basic recognition pattern. Further, we observed that water molecules play significant role for production of supramolecular assemblies.

  4. Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

    Directory of Open Access Journals (Sweden)

    Shawn Matthew Dirk

    2010-11-01

    Full Text Available Phenylpropanoid metabolism yields a mixture of monolignols that undergo chaotic, non-enzymatic reactions such as free radical polymerization and spontaneous self-assembly in order to form the polyphenolic lignin which is a barrier to cost-effective lignocellulosic biofuels. Post-synthesis lignin integration into the plant cell wall is unclear, including how the hydrophobic lignin incorporates into the wall in an initially hydrophilic milieu. Self-assembly, self-organization and aggregation give rise to a complex, 3D network of lignin that displays randomly branched topology and fractal properties. Attempts at isolating lignin, analogous to archaeology, are instantly destructive and non-representative of in planta. Lack of plant ligninases or enzymes that hydrolyze specific bonds in lignin-carbohydrate complexes (LCCs also frustrate a better grasp of lignin. Supramolecular self-assembly, nano-mechanical properties of lignin-lignin, lignin-polysaccharide interactions and association-dissociation kinetics affect biomass deconstruction and thereby cost-effective biofuels production.

  5. A novel self-assembly with zinc porphyrin coordination polymer for enhanced photocurrent conversion in supramolecular solar cells

    International Nuclear Information System (INIS)

    Graphical abstract: An innovative type of self-assembly based on acetohydrazide zinc porphyrin coordination polymer has been prepared in supramolecular solar cells. - Highlights: • A novel assembly with acetohydrazide porphyrin coordination polymer. • The assembly based on porphyrin is prepared as parallel sample. • Coordination polymer-based assembly shows enhanced photoelectronic behavior. • A series of different organic acid ligands as anchoring groups are prepared. - Abstract: In this work, a novel acetohydrazide zinc porphyrin-based coordination polymer (CP)-isonicotinic acid self-assembly by metal-ligand axial coordination to modify the nano-structured TiO2 electrode surface has been investigated in photoelectrochemical device. Compared to the assembly based on corresponding zinc porphyrin combined with isonicotinic acid by metal-ligand axial coordination, CP-isonicotinic acid assembly exhibits a significantly enhanced photoelectronic behavior. In addition, a series of different organic acid ligands were prepared to probe the impact of their structures on the photoelectronic performances of their corresponding assemblies-sensitized cells. This study affords a novel type of self-assembly to functionalize the nanostructured TiO2 electrode surface in supramolecular solar cells

  6. Chapter 8: Selective Stoichiometric and Catalytic Reactivity in the Confines of a Chiral Supramolecular Assembly

    Energy Technology Data Exchange (ETDEWEB)

    University of California, Berkeley; Lawrence Berkeley National Laboratory; Raymond, Kenneth; Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2007-09-27

    increased complexity of synthetic host molecules, most assembly conditions utilize self-assembly to form complex highly-symmetric structures from relatively simple subunits. For supramolecular assemblies able to encapsulate guest molecules, the chemical environment in each assembly--defined by the size, shape, charge, and functional group availability--greatly influences the guest-binding characteristics.[6, 13-17

  7. Improved protocol to purify untagged amelogenin - Application to murine amelogenin containing the equivalent P70→T point mutation observed in human amelogenesis imperfecta.

    Science.gov (United States)

    Buchko, Garry W; Shaw, Wendy J

    2015-01-01

    Amelogenin is the predominant extracellular protein responsible for converting carbonated hydroxyapatite into dental enamel, the hardest and most heavily mineralized tissue in vertebrates. Despite much effort, the precise mechanism by which amelogenin regulates enamel formation is not fully understood. To assist efforts aimed at understanding the biochemical mechanism of enamel formation, more facile protocols to purify recombinantly expressed amelogenin, ideally without any tag to assist affinity purification, are advantageous. Here we describe an improved method to purify milligram quantities of amelogenin that exploits its high solubility in 2% glacial acetic acid under conditions of low ionic strength. The method involves heating the frozen cell pellet for two 15min periods at ∼70°C with 2min of sonication in between, dialysis twice in 2% acetic acid (1:250 v/v), and reverse phase chromatography. A further improvement in yield is obtained by resuspending the frozen cell pellet in 6M guanidine hydrochloride in the first step. The acetic acid heating method is illustrated with a murine amelogenin containing the corresponding P70→T point mutation observed in an human amelogenin associated with amelogenesis imperfecta (P71T), while the guanidine hydrochloride heating method is illustrated with wild type murine amelogenin (M180). The self-assembly properties of P71T were probed by NMR chemical shift perturbation studies as a function of protein (0.1-1.8mM) and NaCl (0-367mM) concentration. Relative to similar studies with wild type murine amelogenin, P71T self-associates at lower protein or salt concentrations with the interactions initiated near the N-terminus.

  8. Responsive supramolecular polymer metallogel constructed by orthogonal coordination-driven self-assembly and host/guest interactions.

    Science.gov (United States)

    Yan, Xuzhou; Cook, Timothy R; Pollock, J Bryant; Wei, Peifa; Zhang, Yanyan; Yu, Yihua; Huang, Feihe; Stang, Peter J

    2014-03-26

    An emerging strategy for the fabrication of advanced supramolecular materials is the use of hierarchical self-assembly techniques wherein multiple orthogonal interactions between molecular precursors can produce new species with attractive properties. Herein, we unify the spontaneous formation of metal-ligand bonds with the host/guest chemistry of crown ethers to deliver a 3D supramolecular polymer network (SPN). Specifically, we have prepared a highly directional dipyridyl donor decorated with a benzo-21-crown-7 moiety that undergoes coordination-driven self-assembly with a complementary organoplatinum acceptor to furnish hexagonal metallacycles. These hexagons subsequently polymerize into a supramolecular network upon the addition of a bisammonium salt due to the formation of [2]pseudorotaxane linkages between the crown ether and ammonium moieties. At high concentrations, the resulting 3D SPN becomes a gel comprising many cross-linked metallohexagons. Notably, thermo- and cation-induced gel-sol transitions are found to be completely reversible, reflecting the dynamic and tunable nature of such supramolecular materials. As such, these results demonstrate the structural complexity that can be obtained when carefully controlling multiple interactions in a hierarchical fashion, in this case coordination and host/guest chemistry, and the interesting dynamic properties associated with the materials thus obtained.

  9. Graphene–cyclodextrin–cytochrome c layered assembly with improved electron transfer rate and high supramolecular recognition capability

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Cheng-Bin; Guo, Cong-Cong; Jiang, Dan; Tang, Qian, E-mail: qiantang@swu.edu.cn; Liu, Chang-Hua; Ma, Xue-Bing

    2014-06-01

    This study aimed to develop a new graphene-based layered assembly, named graphene–cyclodextrin–cytochrome c with improved electron transfer rate. This assembly has combined high conductivity of graphene nanosheets (GNs), selectively binding properties and electronegativity of cyclodextrins (CDs), as well as electropositivity of cytochrome c (Cyt c). This assembly can also mimic the confined environments of the intermembrane space of mitochondria. A β-cyclodextrin (β-CD) functionalized GN (GN–CD) assembly was initially prepared by a simple wet-chemical strategy, i.e., in situ thermal reduction of graphene oxide with hydrazine hydrate in the presence of β-CD. Cyt c was then intercalated to the GN–CD assembly to form a layered self-assembled structure, GN–CD–Cyt c, through electrostatic interaction. Compared with GNs and GN–CD, GN–CD–Cyt c assembly displayed improved electron transfer rate and high supramolecular recognition capability toward six probe molecules. - Highlights: • A new tertiary layered assembly named GN–CD–Cyt c was prepared. • Compared with GNs and GN–CD, GN–CD–Cyt c shows improved electron transfer rate. • GN–CD–Cyt c displays high supramolecular recognition capability.

  10. Reciprocal Self-Assembly of Peptide-DNA Conjugates into a Programmable Sub-10-nm Supramolecular Deoxyribonucleoprotein.

    Science.gov (United States)

    Kye, Mahnseok; Lim, Yong-Beom

    2016-09-19

    To overcome the limitations of molecular assemblies, the development of novel supramolecular building blocks and self-assembly modes is essential to create more sophisticated, complex, and controllable aggregates. The self-assembly of peptide-DNA conjugates (PDCs), in which two orthogonal self-assembly modes, that is, β-sheet formation and Watson-Crick base pairing, are covalently combined in one supramolecular system, is reported. Despite extensive research, most self-assembly studies have focused on using only one type of building block, which restricts structural and functional diversity compared to multicomponent systems. Multicomponent systems, however, suffer from poor control of self-assembly behaviors. Covalently conjugated PDC building blocks are shown to assemble into well-defined and controllable nanostructures. This controllability likely results from the decrease in entropy associated with the restriction of the molecular degrees of freedom by the covalent constraints. Using this strategy, the possibility to thermodynamically program nano-assemblies to exert gene regulation activity with low cytotoxicity is demonstrated. PMID:27553897

  11. Supramolecular Engineering of Hierarchically Self-Assembled, Bioinspired, Cholesteric Nanocomposites Formed by Cellulose Nanocrystals and Polymers.

    Science.gov (United States)

    Zhu, Baolei; Merindol, Remi; Benitez, Alejandro J; Wang, Baochun; Walther, Andreas

    2016-05-01

    Natural composites are hierarchically structured by combination of ordered colloidal and molecular length scales. They inspire future, biomimetic, and lightweight nanocomposites, in which extraordinary mechanical properties are in reach by understanding and mastering hierarchical structure formation as tools to engineer multiscale deformation mechanisms. Here we describe a hierarchically self-assembled, cholesteric nanocomposite with well-defined colloid-based helical structure and supramolecular hydrogen bonds engineered on the molecular level in the polymer matrix. We use reversible addition-fragmentation transfer polymerization to synthesize well-defined hydrophilic, nonionic polymers with a varying functionalization density of 4-fold hydrogen-bonding ureidopyrimidinone (UPy) motifs. We show that these copolymers can be coassembled with cellulose nanocrystals (CNC), a sustainable, stiff, rod-like reinforcement, to give ordered cholesteric phases with characteristic photonic stop bands. The dimensions of the helical pitch are controlled by the ratio of polymer/CNC, confirming a smooth integration into the colloidal structure. With respect to the effect of the supramolecular motifs, we demonstrate that those regulate the swelling when exposing the biomimetic hybrids to water, and they allow engineering the photonic response. Moreover, the amount of hydrogen bonds and the polymer fraction are decisive in defining the mechanical properties. An Ashby plot comparing previous ordered CNC-based nanocomposites with our new hierarchical ones reveals that molecular engineering allows us to span an unprecedented mechanical property range from highest inelastic deformation (strain up to ∼13%) to highest stiffness (E ∼ 15 GPa) and combinations of both. We envisage that further rational design of the molecular interactions will provide efficient tools for enhancing the multifunctional property profiles of such bioinspired nanocomposites. PMID:27067311

  12. Combining modular ligation and supramolecular self-assembly for the construction of star-shaped macromolecules.

    Science.gov (United States)

    Altintas, Ozcan; Muller, Thierry; Lejeune, Elise; Plietzsch, Oliver; Bräse, Stefan; Barner-Kowollik, Christopher

    2012-06-14

    A well-defined random copolymer of styrene (S) and chloromethylstyrene (CMS) featuring lateral chlorine moieties with an alkyne terminal group is prepared (P(S-co-CMS), M(n) = 5500 Da, PDI = 1.13). The chloromethyl groups are converted into Hamilton wedge (HW) entities (P(S-co-HWS), M(n) = 6200 Da, PDI = 1.13). The P(S-co-HWS) polymer is subsequently ligated with tetrakis(4-azidophenyl)methane to give HW-functional star-shaped macromolecules (P(S-co-HWS))(4), M(n) = 25,100 Da, PDI = 1.08). Supramolecular star-shaped copolymers are then prepared via self-assembly between the HW-functionalized four-arm star-shaped macromolecules (P(S-co-HW))(4) and cyanuric acid (CA) end-functionalized PS (PS-CA, M(n) = 3700 Da, PDI = 1.04), CA end-functionalized poly(methyl methacrylate) (PMMA-CA, M(n) = 8500 Da, PDI = 1.13) and CA end-functionalized polyethylene glycol (PEG-CA, M(n) = 1700 Da, PDI = 1.05). The self-assembly is monitored by (1)H NMR spectroscopy and light scattering analyses.

  13. H-bonding directed programmed supramolecular assembly of naphthalene-diimide (NDI) derivatives.

    Science.gov (United States)

    Das, Anindita; Ghosh, Suhrit

    2016-05-25

    In this review we have collated various supramolecular designs, all surrounding H-bonding among well-known functional groups (peptides, nucleic acids, amides, ureas, carboxylic acids, pyridine-hydroxyls, urethanes, imides and others), to dictate self-assembly of naphthalenediimide (NDI) π-systems (both small molecules and polymeric building blocks) that exhibit several exciting features including strong propensity for π-π interactions, π-acidity, excellent n-type semiconductivity, CT-complexation, ion-π interactions, ring-substitution dependent redox properties and photophysical properties. This article reveals that H-bonding can indeed serve as a very powerful and versatile tool to programmed self-assembly of a single or multiple dye system producing a wide range of tailored soft materials, including fibrillar gels, chromonic mesophases, foldamers, nanotubes, vesicles, reverse micelles and polymersomes, both in water and organic medium with distinct photophysical properties, charge transport properties, conductivity properties and functional group displays that are highly relevant in the fields of biology and organic electronics. PMID:27100059

  14. Nanophotonics and supramolecular chemistry

    Science.gov (United States)

    Ariga, Katsuhiko; Komatsu, Hirokazu; Hill, Jonathan P.

    2013-10-01

    Supramolecular chemistry has become a key area in emerging bottom-up nanoscience and nanotechnology. In particular, supramolecular systems that can produce a photonic output are increasingly important research targets and present various possibilities for practical applications. Accordingly, photonic properties of various supramolecular systems at the nanoscale are important in current nanotechnology. In this short review, nanophotonics in supramolecular chemistry will be briefly summarized by introducing recent examples of control of photonic responses of supramolecular systems. Topics are categorized according to the fundamental actions of their supramolecular systems: (i) self-assembly; (ii) recognition; (iii) manipulation.

  15. A luminescent supramolecular assembly composed of a single-walled carbon nanotube and a molecular magnet precursor

    Energy Technology Data Exchange (ETDEWEB)

    Safar, G. A. M., E-mail: gamsafar@yahoo.com.br; Simoes, T. R. G. [Universidade Federal de Minas Gerais, Departamento de Quimica (Brazil); Paula, A. M. de [Universidade Federal de Minas Gerais, Departamento de Fisica (Brazil); Gratens, X.; Chitta, V. A. [Instituto de Fisica, Universidade de Sao Paulo (Brazil); Stumpf, H. O. [Universidade Federal de Minas Gerais, Departamento de Quimica (Brazil)

    2013-02-15

    Magnetism of supramolecular assemblies of single-walled carbon nanotubes (SWCNTS) with a magnetic dinuclear molecule is investigated. Raman, optical absorption and confocal fluorescence images are used to probe the interaction of the dinuclear compound and the SWCNT. The supramolecular assembly shows antiferromagnetism, on the contrary to the case when strong electronic doping of the SWCNT occurs, yielding a spin-glass system, and contrary to the case of the dinuclear molecular crystal, which is ferromagnetic. The SWCNT imposes the antiferromagnetic order to the dinuclear molecule, corroborating recent findings that antiferromagnetism is present in pure SWCNTs. Two theoretical models are used to fit the data, both yielding good fitting results. The nanoparticle size range is around 2-10 nm.

  16. A Ferrocene-Based Catecholamide Ligand: the Consequences of Ligand Swivel for Directed Supramolecular Self-Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Mugridge, Jeffrey; Fiedler, Dorothea; Raymond, Kenneth

    2010-02-04

    A ferrocene-based biscatecholamide ligand was prepared and investigated for the formation of metal-ligand supramolecular assemblies with different metals. Reaction with Ge(IV) resulted in the formation of a variety of Ge{sub n}L{sub m} coordination complexes, including [Ge{sub 2}L{sub 3}]{sup 4-} and [Ge{sub 2}L{sub 2}({mu}-OMe){sub 2}]{sup 2-}. The ligand's ability to swivel about the ferrocenyl linker and adopt different conformations accounts for formation of many different Ge{sub n}L{sub m} species. This study demonstrates why conformational ligand rigidity is essential in the rational design and directed self-assembly of supramolecular complexes.

  17. Supra-molecular assembly of aromatic proton sponges to direct the crystallization of extra-large-pore zeotypes

    OpenAIRE

    Martinez Franco, Raquel; Sun, Junliang; SASTRE NAVARRO, GERMAN IGNACIO; Yun, Yifeng; Zou, Xiaodong; Moliner Marin, Manuel; Corma Canós, Avelino

    2014-01-01

    The combination of different experimental techniques, such as solid C-13 and H-1 magic-angle spinning NMR spectroscopy, fluorescence spectroscopy and powder X-ray diffraction, together with theoretical calculations allows the determination of the unique structure directing the role of the bulky aromatic proton sponge 1,8-bis(dimethylamino)naphthalene (DMAN) towards the extra-large-pore ITQ-51 zeolite through supra-molecular assemblies of those organic molecules. Spanish Government SEV 20...

  18. Assembly of three organic–inorganic hybrid supramolecular materials based on reduced molybdenum(V) phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China); Yu, Kai, E-mail: hlyukai188@163.com [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China); Lv, Jing-Hua; Wang, Chun-Mei; Wang, Chun-Xiao [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China); Zhou, Bai-Bin, E-mail: zhou_bai_bin@163.com [Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025 (China); Key Laboratory of Synthesis of Functional Materials and Green Catalysis, Colleges of Heilongjiang Province, Harbin Normal University, Harbin 150025 (China)

    2014-09-15

    Three supramolecular materials based on (P{sub 4}Mo{sub 6}) polyoxoanions, (Hbbi){sub 2}(H{sub 2}bbi)[Cu{sub 3}Mo{sub 12}{sup V}O{sub 24}(OH){sub 6}(H{sub 2}O){sub 6}(HPO{sub 4}){sub 4}(H{sub 2}PO{sub 4}){sub 2}(PO{sub 4}){sub 2}]·3H{sub 2}O (1), (Hbbi){sub 2}(H{sub 2}bbi)[Ni{sub 3}Mo{sub 12}{sup V}O{sub 24}(OH){sub 6}(H{sub 2}O){sub 2}(HPO{sub 4}){sub 4}(H{sub 2}PO{sub 4}){sub 2}(PO{sub 4}){sub 2}]·9H{sub 2}O (2), (Hbpy)(bpy){sub 3}[Ni{sub 2}(H{sub 2}O){sub 10}Na(PCA){sub 2}][NiMo{sub 12}{sup V}O{sub 24}(OH){sub 6}(H{sub 2}PO{sub 4}){sub 6}(PO{sub 4}){sub 2}]·6H{sub 2}O (3) (bbi=1,1′-(1,4-butanediyl)bis(imidazole), bpy=4,4′-bipyridine, PCA=pyridine-4-carboxylic acid), have been hydrothermally synthesized and structurally characterized by the elemental analysis, TG, IR, UV–vis, PXRD and the single-crystal X-ray diffraction. Compounds 1 and 2 exhibit covalent 1-D chains constructed from M[P{sub 4}Mo{sub 6}]{sub 2} dimeric cluster and (M(H{sub 2}O){sub n}) (M=Cu, n=3 for 1 and M=Ni, n=1 for 2) linker. Compound 3 possesses an unusual POMMOF supramolecular layers based on [Ni(P{sub 4}Mo{sub 6})]{sub 2} dimeric units and 1-D metal–organic strings [Ni(H{sub 2}O){sub 5}Na(PCA)]{sub n}, in which an in situ ligand of PCA from 1,3-bis(4-pyridyl)propane (bpp) precursor was observed. Furthermore, the electrochemical behavior of 1–3-CPE and magnetic properties of 1–3 have been investigated in detail. - Graphical abstract: As new linking unit, Cu(H{sub 2}O){sub 3}, Ni(H{sub 2}O), and (Ni{sub 2}(H{sub 2}O){sub 10}Na(PCA){sub 2}) are introduced into (TM(P{sub 4}Mo{sub 6}){sub 2}) reaction systems to assemble three supramolecular materials under hydrothermal conditions via changing organic ligand and transition metal. - Highlights: • Tree new supramolecular hybrids based on (P{sub 4}Mo{sub 6}) cluster are reported. • Cu(H{sub 2}O){sub 3} and Ni(H{sub 2}O) as linker are introduced into the (TM(P{sub 4}Mo{sub 6}){sub 2}) systems. • 3 shows unusual layers based on

  19. Self-assembly of supramolecular triarylamine nanowires in mesoporous silica and biocompatible electrodes thereof

    Science.gov (United States)

    Licsandru, Erol-Dan; Schneider, Susanne; Tingry, Sophie; Ellis, Thomas; Moulin, Emilie; Maaloum, Mounir; Lehn, Jean-Marie; Barboiu, Mihail; Giuseppone, Nicolas

    2016-03-01

    Biocompatible silica-based mesoporous materials, which present high surface areas combined with uniform distribution of nanopores, can be organized in functional nanopatterns for a number of applications. However, silica is by essence an electrically insulating material which precludes applications for electro-chemical devices. The formation of hybrid electroactive silica nanostructures is thus expected to be of great interest for the design of biocompatible conducting materials such as bioelectrodes. Here we show that we can grow supramolecular stacks of triarylamine molecules in the confined space of oriented mesopores of a silica nanolayer covering a gold electrode. This addressable bottom-up construction is triggered from solution simply by light irradiation. The resulting self-assembled nanowires act as highly conducting electronic pathways crossing the silica layer. They allow very efficient charge transfer from the redox species in solution to the gold surface. We demonstrate the potential of these hybrid constitutional materials by implementing them as biocathodes and by measuring laccase activity that reduces dioxygen to produce water.Biocompatible silica-based mesoporous materials, which present high surface areas combined with uniform distribution of nanopores, can be organized in functional nanopatterns for a number of applications. However, silica is by essence an electrically insulating material which precludes applications for electro-chemical devices. The formation of hybrid electroactive silica nanostructures is thus expected to be of great interest for the design of biocompatible conducting materials such as bioelectrodes. Here we show that we can grow supramolecular stacks of triarylamine molecules in the confined space of oriented mesopores of a silica nanolayer covering a gold electrode. This addressable bottom-up construction is triggered from solution simply by light irradiation. The resulting self-assembled nanowires act as highly conducting

  20. Structure-Property Relationship for Two-Photon Absorbing Multiporphyrins: Supramolecular Assembly of Highly-Conjugated Multiporphyrinic Ladders and Prisms

    Energy Technology Data Exchange (ETDEWEB)

    Easwaramoorthi, Shanmugam; Jang, So Young; Yoon, Zin Seok; Lim, Jong Min; Lee, Cheng-Wei; Mai, Chi-Lun; Liu, Yen-Chun; Yeh, Chen-Yu; Vura-Weis, Josh; Wasielewski, Michael R.; Kim, Dongho (NWU); (Yonsei); (NSHU)

    2008-10-03

    Two-photon absorption (TPA) phenomena of a series of single-strand as well as supramolecular self-assembled ladders and prisms of highly conjugated ethyne bridged multiporphyrin dimer, trimer, and star shaped pentamer have been investigated. The ligand mediated self-assembled supramolecular structures were characterized by UV-visible spectroscopy and small- and wide-angle X-ray scattering (SAXS/WAXS) analysis. The TPA cross section values of multiporphyrins increase nonlinearly from {approx}100 to {approx}18000 GM with an increased number of porphyrin units and elongated ?-conjugation length by virtue of charge transfer and excited-state cumulenic configurations. The observed opposite TPA behavior between their supramolecular ladder and prism configurations necessitates the importance of interstrand interactions between the multiporphyrinic units and the overall shape of the assembly. Furthermore, the diminished TPA cross section of the pentamer, despite the increased ?-conjugation resulting from duplex formation suggests that destabilizing the essential functional configurations at the cost of elongation of ?-delocalization pathway must cause unfavorable effects. We have also shown that one- and two-photon allowed energy-levels of linear multiporphyrins are nearly isoenergetic and the latter transition originates exclusively from the extent of ?-delocalization within the molecule. The identical TPA maximum position of the trimer and pentamer indicates that the TPA of the pentamer arises only from its basic trimer unit in spite of its extended two-dimensional {pi}-conjugation pathway involving five porphyrinic units.

  1. Steric hindrance regulated supramolecular assembly between β-cyclodextrin polymer and pyrene for alkaline phosphatase fluorescent sensing

    Science.gov (United States)

    Song, Chunxia; Yang, Xiaohai; Wang, Kemin; Wang, Qing; Liu, Jianbo; Huang, Jin; Zhou, Maogui; Guo, Xiaochen

    2016-03-01

    We herein report a strategy for sensitive alkaline phosphatase (ALP) fluorescent sensing based on steric hindrance regulated supramolecular assembly between β-cyclodextrin polymer (polyβ-CD) and pyrene. The fluorescence of pyrene was enhanced more than 10 times through supramolecular assembly with polyβ-CD. The 5‧-phosphorylated dsDNA probe with pyrene attached on the 3‧-terminal could be cleaved by λ exonuclease (λ exo), yielding pyrene attached on mononucleotides. Pyrene attached on mononucleotides could easily enter the cavity of polyβ-CD, resulting in fluorescence enhancement. When ALP was introduced, it could remove 5‧-phosphate groups from dsDNA and then prevented the cleavage of dsDNA. Pyrene attached on dsDNA was difficult to enter the cavity of polyβ-CD because of steric hindrance, resulting in an inconspicuous fluorescence enhancement. Owing to the excellent fluorescence enhancement during steric hindrance regulated supramolecular assembly, excellent performance of the assay method was achieved for ALP with a detection limit of 0.04 U mL- 1. The detection limit was superior or comparable with the reported methods. Besides, this method was simple in design, avoiding double-labeling of probe.

  2. Self-healing supramolecular bioelastomers with shape memory property as a multifunctional platform for biomedical applications via modular assembly.

    Science.gov (United States)

    Wu, Yaobin; Wang, Ling; Zhao, Xin; Hou, Sen; Guo, Baolin; Ma, Peter X

    2016-10-01

    Mimicking native functional dynamics for traditional biomaterials such as thermoset elastomers is limited due to their lack of responsiveness to biological stimuli and difficulties to incorporate biofunctionalities. Furthermore, the mechanical fracture of traditional thermoset elastomers caused by irreversible covalent bond rupture would lead to their permanent loss of properties. To overcome these challenges, degradable self-healed supramolecular bioelastomers are designed by an elastic poly(glycerol sebacate) (PGS) backbone and multiple hydrogen-bonding ureido-pyrimidinone (UPy) grafts. These supramolecular elastic polymers exhibit efficient self-healing, rapid shape-memory abilities and highly tunable mechanical properties due to the dynamic supramolecular interactions, and perform a good biocompatibility in vitro and a mild host response in vivo. By combining modular approaches, these supramolecular bioelastomers have been further assembled into a multifunctional platform to expand their applications in different biomedical fields. These include a complex 3D scaffold with shape-memory capacity and anisotropic mechanical properties, a controllable drug delivery model via a layer-by-layer technique, a surface antibacterial composite by physical modification, and a spatial oriented cell co-culture system via incorporating different cell-laden self-healing films, demonstrating their potential as building blocks in a wide range of biomedical applications where dynamic properties and biological functions are desired.

  3. Self-healing supramolecular bioelastomers with shape memory property as a multifunctional platform for biomedical applications via modular assembly.

    Science.gov (United States)

    Wu, Yaobin; Wang, Ling; Zhao, Xin; Hou, Sen; Guo, Baolin; Ma, Peter X

    2016-10-01

    Mimicking native functional dynamics for traditional biomaterials such as thermoset elastomers is limited due to their lack of responsiveness to biological stimuli and difficulties to incorporate biofunctionalities. Furthermore, the mechanical fracture of traditional thermoset elastomers caused by irreversible covalent bond rupture would lead to their permanent loss of properties. To overcome these challenges, degradable self-healed supramolecular bioelastomers are designed by an elastic poly(glycerol sebacate) (PGS) backbone and multiple hydrogen-bonding ureido-pyrimidinone (UPy) grafts. These supramolecular elastic polymers exhibit efficient self-healing, rapid shape-memory abilities and highly tunable mechanical properties due to the dynamic supramolecular interactions, and perform a good biocompatibility in vitro and a mild host response in vivo. By combining modular approaches, these supramolecular bioelastomers have been further assembled into a multifunctional platform to expand their applications in different biomedical fields. These include a complex 3D scaffold with shape-memory capacity and anisotropic mechanical properties, a controllable drug delivery model via a layer-by-layer technique, a surface antibacterial composite by physical modification, and a spatial oriented cell co-culture system via incorporating different cell-laden self-healing films, demonstrating their potential as building blocks in a wide range of biomedical applications where dynamic properties and biological functions are desired. PMID:27424213

  4. Autonomous oscillation in supramolecular assemblies: Role of free energy landscape and fluctuations

    Science.gov (United States)

    Sereda, Yuriy V.; Ortoleva, Peter J.

    2015-11-01

    Molecular dynamics studies demonstrated that a supramolecular assembly can express autonomous structural oscillations about equilibrium. It is demonstrated here that for nanosystems such oscillations can result from the interplay of free energy landscape and structural fluctuations. Furthermore, these oscillations have intermittent character, reflecting the conflict between a tendency to oscillate due to features in the free energy landscape, and the Second Law's repression of perpetual oscillation in an isothermal, equilibrium system. The demonstration system is a T = 1 icosahedral structure constituted of 12 protein pentamers in contact with a bath at fixed temperature. The oscillations are explained in terms of a Langevin model accounting for interactions among neighboring pentamers. The model is based on a postulated free energy landscape in the 24-dimensional space of variables describing the centrifugal and rotational motion of each pentamer. The model includes features such as basins of attraction and low free energy corridors. When the system is driven slightly out of equilibrium, the oscillations are transformed into a limit cycle, as expressed in terms of power spectrum narrowing.

  5. Template Syntheses, Crystal Structures and Supramolecular Assembly of Hexaaza Macrocyclic Copper(II) Complexes

    International Nuclear Information System (INIS)

    Two new hexaaza macrocyclic copper(II) complexes were prepared by a template method and structurally characterized. In the solid state, they were self-assembled by intermolecular interactions to form the corresponding supramolecules 1 and 2, respectively. In the structure of 1, the copper(II) macrocycles are bridged by a tp ligand to form a macrocyclic copper(II) dimer. The dimer extends its structure by intermolecular forces such as hydrogen bonds and C-H···π interactions, resulting in the formation of a double stranded 1D supramolecule. In 2, the basic structure is a monomeric copper(II) macrocycle with deprotonated imidazole pendants. An undulated 1D hydrogen bonded array is achieved through hydrogen bonds between imidazole pendants and secondary amines, where the imidazole pendants act as a hydrogen bond acceptor. The 1D hydrogen bonded supramolecular chain is supported by C-H···π interactions between the methyl groups of acetonitrile ligands and imidazole pendants of the copper(II) macrocycles. In both complexes, the introduction of imidazoles to the macrocycle as a pendant plays an important role for the formation of supramolecules, where they act as intermolecular hydrogen bond donors and/or acceptors, C-H···π and π-π interactions

  6. Self-Healing Supramolecular Self-Assembled Hydrogels Based on Poly(L-glutamic acid).

    Science.gov (United States)

    Li, Guifei; Wu, Jie; Wang, Bo; Yan, Shifeng; Zhang, Kunxi; Ding, Jianxun; Yin, Jingbo

    2015-11-01

    Self-healing polymeric hydrogels have the capability to recover their structures and functionalities upon injury, which are extremely attractive in emerging biomedical applications. This research reports a new kind of self-healing polypeptide hydrogels based on self-assembly between cholesterol (Chol)-modified triblock poly(L-glutamic acid)-block-poly(ethylene glycol)-block-poly(L-glutamic acid) ((PLGA-b-PEG-b-PLGA)-g-Chol) and β-cyclodextrin (β-CD)-modified poly(L-glutamic acid) (PLGA-g-β-CD). The hydrogel formation relied on the host and guest linkage between β-CD and Chol. This study demonstrates the influences of polymer concentration and β-CD/Chol molar ratio on viscoelastic behavior of the hydrogels. The results showed that storage modulus was highest at polymer concentration of 15% w/v and β-CD/Chol molar ratio of 1:1. The effect of the PLGA molecular weight in (PLGA-b-PEG-b-PLGA)-g-Chol on viscoelastic behavior, mechanical properties and in vitro degradation of the supramolecular hydrogels was also studied. The hydrogels showed outstanding self-healing capability and good cytocompatibility. The multilayer structure was constructed using hydrogels with self-healing ability. The developed hydrogels provide a fascinating glimpse for the applications in tissue engineering. PMID:26414083

  7. Fabrication of CO2 Facilitated Transport Channels in Block Copolymer through Supramolecular Assembly

    Directory of Open Access Journals (Sweden)

    Yao Wang

    2014-05-01

    Full Text Available In this paper, the molecule 12-amidine dodecanoic acid (M with ending groups of carboxyl and amidine groups respectively was designed and synthesized as CO2-responsive guest molecules. The block copolymer polystyrene-b-polyethylene oxide (PS-b-PEO was chosen as the host polymer to fabricate a composite membrane through H-bonding assembly with guest molecule M. We attempted to tune the phase separation structure of the annealed film by varying the amount of M added, and investigated the nanostructures via transmission electron microscope (TEM, fourier transform infrared (FT-IR etc. As a result, a reverse worm-like morphology in TEM image of bright PS phase in dark PEO/M matrix was observed for PS-b-PEO/M1 membrane in which the molar ratio of EO unit to M was 1:1. The following gas permeation measurement indicated that the gas flux of the annealed membranes dramatically increased due to the forming of ordered phase separation structure. As we expected, the obtained composite membrane PS-b-PEO/M1 with EO:M mole ratio of 1:1 presented an evident selectivity for moist CO2 permeance, which is identical with our initial proposal that the guest molecule M in the membranes will play the key role for CO2 facilitated transportation since the amidine groups of M could react reversibly with CO2 molecules in membranes. This work provides a supramolecular approach to fabricating CO2 facilitated transport membranes.

  8. Self-Assembly of Polyoxometalate and Polyelectrolyte Macroions into Mechanically Strong Supramolecular Hydrogels

    Science.gov (United States)

    Jing, Benxin; Zhu, Y. Elaine

    Polyoxometalate (POM) macroions are the nanoclusters of transition metal oxide with size 1-10 nm and well-defined structure at the atom level. Because of their stoichiometric surface groups and high solubility in polar solvents to form thermodynamically stable solution, POMs are studied as excellent model macroions at nanoscale. In this work, we explore the electrostatic controlled self-assembly of anionic POMs and cationic or zwitterionic polyelectrolytes (PEs) in aqueous solution. Specifically we examine the complex formation of zwitterionic poly (3-(methacryloylamino)propyl]dimethyl(3-sulfopropyl)ammonium hydroxide) (PSBMA) and cationic poly(diallyldimethylammonium chloride) (PDADMAC) with tungstate based POMs of varied valence. The phase diagram of POM/polyelectrolyte complexes is determined with varied POM/PE charge ratios. It is interesting to observe the coacervation of POMs with PSBMA. With cationic PDADMAC, hybrid POM-PDADMAC hydrogels can be formed. Nevertheless, POM-PDADMAC complexes exhibit much enhanced mechanical properties in comparison to polymer hydrogel. The viscoelastic properties of hybrid macroion complexes strongly depend on PDADMAC concentration, POM-to-PDADMAC molar ratio, the size and valence of POMs. At the intermediate range of POM-to-PDADMAC concentration ratio, shear thickening and strain hardening are observed with soft supramolecular hydrogels, which is resulted from the non-Gaussian stretching of polymer chains.

  9. Self-Healing Supramolecular Self-Assembled Hydrogels Based on Poly(L-glutamic acid).

    Science.gov (United States)

    Li, Guifei; Wu, Jie; Wang, Bo; Yan, Shifeng; Zhang, Kunxi; Ding, Jianxun; Yin, Jingbo

    2015-11-01

    Self-healing polymeric hydrogels have the capability to recover their structures and functionalities upon injury, which are extremely attractive in emerging biomedical applications. This research reports a new kind of self-healing polypeptide hydrogels based on self-assembly between cholesterol (Chol)-modified triblock poly(L-glutamic acid)-block-poly(ethylene glycol)-block-poly(L-glutamic acid) ((PLGA-b-PEG-b-PLGA)-g-Chol) and β-cyclodextrin (β-CD)-modified poly(L-glutamic acid) (PLGA-g-β-CD). The hydrogel formation relied on the host and guest linkage between β-CD and Chol. This study demonstrates the influences of polymer concentration and β-CD/Chol molar ratio on viscoelastic behavior of the hydrogels. The results showed that storage modulus was highest at polymer concentration of 15% w/v and β-CD/Chol molar ratio of 1:1. The effect of the PLGA molecular weight in (PLGA-b-PEG-b-PLGA)-g-Chol on viscoelastic behavior, mechanical properties and in vitro degradation of the supramolecular hydrogels was also studied. The hydrogels showed outstanding self-healing capability and good cytocompatibility. The multilayer structure was constructed using hydrogels with self-healing ability. The developed hydrogels provide a fascinating glimpse for the applications in tissue engineering.

  10. Supramolecularly assembled water layers stabilized by sebacic anions in complexes of Zn(II) and Co(II)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Two three-dimensional supramolecular water architectures,[Zn(phen)3]2 ·[Zn(C10H16O4)·(H2O)3]·(C10H16O4)2·20H2O(1) and [Co(phen)3]2 ·[Co(H2O)6]·(C10H16O4)3·30H2O(2)[phen=1,10-Phenanthroline,C10H16O4=sebacic dianion],have been synthesized and characterized by IR,elemental analysis,thermogravimetric analysis,and single-crystal X-ray diffractions.The two structures both contain extensive hydrogen bonding between water molecules as well as between water molecules and sebacic anions.The water molecules and sebacic acid O atoms assembled 2D supramolecular corrugated sheets with different morphology in the two complexes.

  11. Supramolecular Assemblies in Salts of 2,2'-Biimidazole with 5-Sulfosalicylic Acid and 3,4,5-Trihydroxybenzoic Acid

    Institute of Scientific and Technical Information of China (English)

    LI Yan-Ping; YANG Pin

    2007-01-01

    Supramolecular assemblies of 2,2'-biimidazole with 5-sulfosalicylic acid and 3,4,5-trihydroxybenzoic acid, have been synthesized and characterized by single-crystal X-ray diffraction methods. Both the two proton-transfer compounds of 2,2'-biimidazole with 3-carboxy-4-hydroxybenzenesulfonic acid (5-sulfosalicylic acid, 5-SSA) [namely structures having significant interlayer π-π interactions between the cation and anion species. In Ⅰ, a 5-SSA2- dianionic species results from deprotonation of both the sulfonic and the carboxylic acid groups, all available O-atom acceptors interact with all cation and water molecule donors by hydrogen bonds. In Ⅱ, the formula unit displays a crystallographic inversion symmetry. The structural information about the two complexes between 2,2'-biimidazole compound and benzenecarboxylic acids obtained in this work will be particularly important for the rational design of supramolecular organic functional materials.

  12. Supramolecular polymers in inhomogeneous systems

    OpenAIRE

    Zweistra, H.J.A.

    2007-01-01

    This thesis describes theoretical results of supramolecular polymers in inhomogeneous systems. Supramolecular polymers are linear assemblies of which the monomers are joined by reversible bonds. Many types of supramolecular polymers have been synthesized in recent years. Moreover, there are numerous compounds in nature which exhibit similar behavior. Simulations of coarse-grained models of supramolecular polymers yielded new insights into the properties of supramolecular polymers in inhomogen...

  13. Investigation of Porphyrin and Lipid Supramolecular Assemblies for Cancer Imaging and Therapy

    Science.gov (United States)

    Ng, Kenneth Ka-Seng

    Aerobic life on earth is made possible through the functions of the porphyrin. These colorful and ubiquitous chromophores are efficient at concentrating and converting sunlight into chemical energetic potential which sustain biological life. Humans have had a longstanding fascination with these molecules, especially for their applications in photodynamic therapy. The photophysical properties of porphyrins are highly influenced by their surrounding environment. Intermolecular interactions between these pigments can lead to excited state quenching, energy transfer and large changes to their absorption and fluorescence spectra. This thesis is focused on utilizing molecular self-assembly strategies to develop nanoscale porphyrin and phospholipid structures. The rationale being that intermolecular interactions between porphyrins in these nanostructures can induce changes which can be exploited in novel biomedical imaging and therapeutic applications. Four lipid-based structural platforms are studied including: nanoemulsions, bilayer discs and nanovesicles. In Chapter 1, I provide a background on the photophysics of porphyrins and the effect of intermolecular porphyrin interactions on photophysical properties. I also discuss phospholipids and their self-assembly process. Lastly I review current biomedical photonics techniques and discuss how these strategies can be used in conjugation with porphyrin and lipid supramolecular assemblies. In Chapter 2, I investigate the influence that loading a novel bacteriochlorin photosensitizer into a protein-stabilized lipid emulsion has on its spectral properties. I discovered that while the dye can be incorporated into the lipid emulsion, no changes were observed in its spectral properties. In Chapter 3, an amphipathic alpha-helical protein is used to stabilize and organize porphyrin-lipid molecules into bilayer discs. Close packing between porphyrin molecules causes quenching, which can be reversed by structural degradation of the

  14. A unique quinolineboronic acid-based supramolecular structure that relies on double intermolecular B-N bonds for self-assembly in solid state and in solution.

    Science.gov (United States)

    Zhang, Yanling; Li, Minyong; Chandrasekaran, Sekar; Gao, Xingming; Fang, Xikui; Lee, Hsiau-Wei; Hardcastle, Kenneth; Yang, Jenny; Wang, Binghe

    2007-04-16

    The boronic acid functional group plays very important roles in sugar recognition, catalysis, organic synthesis, and supramolecular assembly. Therefore, understanding the unique properties of this functional group is very important. 8-Quinolineboronic acid (8-QBA) is found to be capable of self-assembling in solid state through a unique intermolecular B-N bond mechanism reinforced by intermolecular boronic anhydride formation, π-π stacking, and hydrogen bond formation. NMR NOE and diffusion studies indicate that intermolecular B-N interaction also exists in solution with 8-QBA. In contrast, a positional isomer of 8-QBA, 5-quinolineboronic acid (5-QBA) showed very different behaviors in crystal packing and in solution and therefore different supramolecular network. Understanding the structural features of this unique 8-QBA assembly could be very helpful for the future design of new sugar sensors, molecular catalysts, and supramolecular assemblies. PMID:18414645

  15. Supra-molecular assembly of a lumican-derived peptide amphiphile enhances its collagen-stimulating activity.

    Science.gov (United States)

    Walter, Merlin N M; Dehsorkhi, Ashkan; Hamley, Ian W; Connon, Che J

    2016-02-01

    C16-YEALRVANEVTLN, a peptide amphiphile (PA) incorporating a biologically active amino acid sequence found in lumican, has been examined for its influence upon collagen synthesis by human corneal fibroblasts in vitro, and the roles of supra-molecular assembly and activin receptor-like kinase ALK receptor signaling in this effect were assessed. Cell viability was monitored using the Alamar blue assay, and collagen synthesis was assessed using Sirius red. The role of ALK signaling was studied by receptor inhibition. Cultured human corneal fibroblasts synthesized significantly greater amounts of collagen in the presence of the PA over both 7-day and 21-day periods. The aggregation of the PA to form nanotapes resulted in a notable enhancement in this activity, with an approximately two-fold increase in collagen production per cell. This increase was reduced by the addition of an ALK inhibitor. The data presented reveal a stimulatory effect upon collagen synthesis by the primary cells of the corneal stroma, and demonstrate a direct influence of supra-molecular assembly of the PA upon the cellular response observed. The effects of PA upon fibroblasts were dependent upon ALK receptor function. These findings elucidate the role of self-assembled nanostructures in the biological activity of peptide amphiphiles, and support the potential use of a self-assembling lumican derived PA as a novel biomaterial, intended to promote collagen deposition for wound repair and tissue engineering purposes. PMID:26626506

  16. Electrochemically controlled supramolecular systems

    NARCIS (Netherlands)

    Nijhuis, Christian A.; Ravoo, Bart Jan; Huskens, Jurriaan; Reinhoudt, David N.

    2007-01-01

    Large and complex molecular structures can be assembled by supramolecular chemistry and self-organization. For practical purposes it is required that the assembly and disassembly of supramolecular complexes and materials can be directed and controlled by external stimuli in order to build, for insta

  17. Supramolecular Assemblies of(±)-2,2'-Dihydroxy-1,1'-binaphthyl with 2,2'-Bipyridine and Naphthodiazine

    Institute of Scientific and Technical Information of China (English)

    JI Bao-Ming吉保明; CHEN Hua-Ting陈花婷; DU Chen-Xia杜晨霞; DING Kui-Ling丁奎岭

    2004-01-01

    Supramolecular assemblies of (±)-2,2'-dihydroxy-l,l'-binaphthyl (BINOL, A), with aza donor molecules including 2,2'-bipyridine (B) and naphthodiazine (C), have been synthesized and characterized by single-crystal X-ray diffraction methods. Two inclusion complexes crystallize in the triclinic system with P-1 space group. In the inclusion complex between A and B, two molecules of A and two molecules of B are linked each other by intermolecular hydrogen bonds with two molecules of water as the bridges, forming a centrosymmetric dimer with formula of A2(H2O)2B2; while in the inclusion complex between A and C, the molecule C virtually acts as a bridge to link molecules A through intermolecular O-H...N hydrogen bonds, forming a short-chain supramolecular block with interactions also play an important role in the solid-state packing of these two inclusion complexes. The structural information disclosed on the complex between dihydroxy compound and aza hydrogen bond acceptors in this work would be particularly important for the rational design of supramolecular organic functional materials.

  18. Two 3D supramolecular frameworks assembled from the dinuclear building block: A crystallographic evidence of carboxylate(O)$\\ldots$ interaction

    Indian Academy of Sciences (India)

    Sudip Mohapatra; Syamantak Roy; Debajyoti Ghoshal; Tapas Kumar Maji

    2014-07-01

    Two new complexes of Mn(II) and Zn(II) have been synthesized using a mixed ligand system and characterized by IR spectroscopy, elemental analysis, single crystal x-ray diffraction and variable temperature magnetic study for one of the compounds. Dimeric coordination structures of [Mn2(2,4-pyrdc)2(bpe)(H2O)6]·2H2O (1) and [Zn2(2,4-pyrdc)2(azpy)(H2O)6]·2H2O (2) [2,4-pyrdc = 2,4-pyridinedicarboxylate; bpe = 1,2-bis(4-pyridyl)ethane; azpy = 4, 4' azopyridine] are constructed by the bridging of bpe and azpy, respectively and both are extended to a 3D supramolecular structure by non-covalent interactions. In both the cases, unprecedented carboxylate(O)$\\ldots$ interactions played a crucial role in the organization of the 3D supramolecular assembly. The carboxylate(O)$\\ldots$ interactions are controlled by the C-H$\\ldots$ interactions which were accomplished by the proper modulation of the organic linkers. The formation of these supramolecular frameworks revealed that control of weak interactions can be achieved by the interplay of both energetically strong (covalent) and weak forces (non-covalent).

  19. Biocatalytic self-assembly of supramolecular charge-transfer nanostructures based on n-type semiconductor-appended peptides.

    Science.gov (United States)

    Nalluri, Siva Krishna Mohan; Berdugo, Cristina; Javid, Nadeem; Frederix, Pim W J M; Ulijn, Rein V

    2014-06-01

    The reversible in situ formation of a self-assembly building block (naphthalenediimide (NDI)-dipeptide conjugate) by enzymatic condensation of NDI-functionalized tyrosine (NDI-Y) and phenylalanine-amide (F-NH2) to form NDI-YF-NH2 is described. This coupled biocatalytic condensation/assembly approach is thermodynamically driven and gives rise to nanostructures with optimized supramolecular interactions as evidenced by substantial aggregation induced emission upon assembly. Furthermore, in the presence of di-hydroxy/alkoxy naphthalene donors, efficient charge-transfer complexes are produced. The dynamic formation of NDI-YF-NH2 and electronic and H-bonding interactions are analyzed and characterized by different methods. Microscopy (TEM and AFM) and rheology are used to characterize the formed nanostructures. Dynamic nanostructures, whose formation and function are driven by free-energy minimization, are inherently self-healing and provide opportunities for the development of aqueous adaptive nanotechnology. PMID:24788665

  20. The Self-Assembly of Nano-Objects Code: Applications to supramolecular organic monolayers adsorbed on metal surfaces

    CERN Document Server

    Roussel, Thomas

    2012-01-01

    The Self-Assembly of Nano-Objects (SANO) code we implemented demonstrates the ability to predict the molecular self-assembly of different structural motifs by tuning the molecular building blocks as well as the metallic substrate. It consists in a two-dimensional Grand Canonical Monte-Carlo (GCMC) approach developed to perform atomistic simulations of thousands of large organic molecules self-assembling on metal surfaces. Computing adsorption isotherms at room temperature and spanning over the characteristic sub-micrometric scales, we confront the robustness of the approach with three different well-known systems: ZnPcCl8 on Ag(111), CuPcF16 on Au(111) and PTBC on Ag(111). We retrieve respectively their square, oblique and hexagonal supramolecular tilling. The code incorporates generalized force fields to describe the molecular interactions, which provides transferability and versatility to many organic building blocks and metal surfaces.

  1. Solvent-polarity-tuned morphology and inversion of supramolecular chirality in a self-assembled pyridylpyrazole-linked glutamide derivative: nanofibers, nanotwists, nanotubes, and microtubes.

    Science.gov (United States)

    Jin, Qingxian; Zhang, Li; Liu, Minghua

    2013-07-01

    The self-assembly of a low-molecular-weight organogelator into various hierarchical structures has been achieved for a pyridylpyrazole linked L-glutamide amphiphile in different solvents. Upon gel formation, supramolecular chirality was observed, which exhibited an obvious dependence on the polarity of the solvent. Positive supramolecular chirality was obtained in nonpolar solvents, whereas it was inverted into negative supramolecular chirality in polar solvents. Moreover, the gelator molecules self-assembled into a diverse array of nanostructures over a wide scale range, from nanofibers to nanotubes and microtubes, depending on the solvent polarity. Such morphological changes could even occur for the xerogels in the solvent vapors. We found that the interactions between the pyridylpyrazole headgroups and the solvents could subtly change the stacking of the molecules and, hence, their self-assembled nanostructures. This work exemplifies that organic solvents can significantly involve the gelation, as well as tune the structure and properties, of a gel.

  2. A supramolecular Janus hyperbranched polymer and its photoresponsive self-assembly of vesicles with narrow size distribution.

    Science.gov (United States)

    Liu, Yong; Yu, Chunyang; Jin, Haibao; Jiang, Binbin; Zhu, Xinyuan; Zhou, Yongfeng; Lu, Zhongyuan; Yan, Deyue

    2013-03-27

    Herein, we report a novel Janus particle and supramolecular block copolymer consisting of two chemically distinct hyperbranched polymers, which is coined as Janus hyperbranched polymer. It is constructed by the noncovalent coupling between a hydrophobic hyperbranched poly(3-ethyl-3-oxetanemethanol) with an apex of an azobenzene (AZO) group and a hydrophilic hyperbranched polyglycerol with an apex of a β-cyclodextrin (CD) group through the specific AZO/CD host-guest interactions. Such an amphiphilic supramolecular polymer resembles a tree together with its root very well in the architecture and can further self-assemble into unilamellar bilayer vesicles with narrow size distribution, which disassembles reversibly under the irradiation of UV light due to the trans-to-cis isomerization of the AZO groups. In addition, the obtained vesicles could further aggregate into colloidal crystal-like close-packed arrays under freeze-drying conditions. The dynamics and mechanism for the self-assembly of vesicles as well as the bilayer structure have been disclosed by a dissipative particle dynamics simulation. PMID:23464832

  3. Fabrication of Highly Ordered Polymeric Nanodot and Nanowire Arrays Templated by Supramolecular Assembly Block Copolymer Nanoporous Thin Films

    Directory of Open Access Journals (Sweden)

    Liu Xikui

    2009-01-01

    Full Text Available Abstract Realizing the vast technological potential of patternable block copolymers requires both the precise controlling of the orientation and long-range ordering, which is still a challenging topic so far. Recently, we have demonstrated that ordered nanoporous thin film can be fabricated from a simple supramolecular assembly approach. Here we will extend this approach and provide a general route to fabricate large areas of highly ordered polymeric nanodot and nanowire arrays. We revealed that under a mixture solvent annealing atmosphere, a near-defect-free nanoporous thin film over large areas can be achieved. Under the direction of interpolymer hydrogen bonding and capillary action of nanopores, this ordered porous nanotemplate can be properly filled with phenolic resin precursor, followed by curation and pyrolysis at middle temperature to remove the nanotemplate, a perfect ordered polymer nanodot arrays replication was obtained. The orientation of the supramolecular assembly thin films can be readily re-aligned parallel to the substrate upon exposure to chloroform vapor, so this facile nanotemplate replica method can be further extend to generate large areas of polymeric nanowire arrays. Thus, we achieved a successful sub-30 nm patterns nanotemplates transfer methodology for fabricating polymeric nanopattern arrays with highly ordered structure and tunable morphologies.

  4. Self-assembly and supramolecular liquid crystals based on organic cation encapsulated polyoxometalate hybrid reverse micelles and pyridine derivatives.

    Science.gov (United States)

    Yin, Shengyan; Sun, Hang; Yan, Yi; Zhang, Hui; Li, Wen; Wu, Lixin

    2011-09-15

    The controlled self-assembly of multi-components in one system represents the capability integrating intermolecular interactions and functions of components and is believed the key procedure leading to multifunctional materials finally. In pursuing this goal, we used a double-chain cationic surfactant with a benzoic acid group at the end of one tail to encapsulate Keggin-type polyanion clusters via electrostatic interaction, obtaining uniform supramolecular hybrid reverse micelles, which served as hydrogen-bonding donors. Five pyridine derivatives containing conjugated and non-conjugated groups were chosen as hydrogen-bonding acceptors to bind with reverse micelles. Through mixing with these components according to chemical stoichiometry, the hybrid reverse micelle changed to a new self-assembly precursor through intermolecular hydrogen bonding. The as-prepared reverse micelles bearing conjugated pyridine groups exhibit supramolecular liquid crystal properties, which were characterized by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. The length and number of the alky chain in the pyridine derivatives, as well as the charges of polyoxometalates were also studied with regard to the liquid crystal structure. The synergistic effect of among three components was analyzed, and the liquid crystal properties could be conveniently adjusted through the modification of the hydrogen-bonding acceptor components.

  5. Amelogenin, an extracellular matrix protein, in the treatment of venous leg ulcers and other hard-to-heal wounds: experimental and clinical evidence

    DEFF Research Database (Denmark)

    Romanelli, M.; Dini, V.; Vowden, P.;

    2008-01-01

    Amelogenins are extracellular matrix proteins that, under physiological conditions, self-assemble into globular aggregates up to micron-sizes. Studies with periodontal fibroblasts indicate that attachment to these structures increases the endogenous secretion of multiple growth factors and cell...

  6. Lanthanide-directed synthesis of luminescent self-assembly supramolecular structures and mechanically bonded systems from acyclic coordinating organic ligands.

    Science.gov (United States)

    Barry, Dawn E; Caffrey, David F; Gunnlaugsson, Thorfinnur

    2016-06-01

    Herein some examples of the use of lanthanide ions (f-metal ions) to direct the synthesis of luminescent self-assembly systems (architectures) will be discussed. This area of lanthanide supramolecular chemistry is fast growing, thanks to the unique physical (magnetic and luminescent) and coordination properties of the lanthanides, which are often transferred to the resulting supermolecule. The emphasis herein will be on systems that are luminescent, and hence, generated by using either visibly emitting ions (such as Eu(III), Tb(III) and Sm(III)) or near infrared emitting ions (like Nd(III), Yb(III) and Er(III)), formed through the use of templating chemistry, by employing structurally simple ligands, possessing oxygen and nitrogen coordinating moieties. As the lanthanides have high coordination requirements, their use often allows for the formation of coordination compounds and supramolecular systems such as bundles, grids, helicates and interlocked molecules that are not synthetically accessible through the use of other commonly used templating ions such as transition metal ions. Hence, the use of the rare-earth metal ions can lead to the formation of unique and stable species in both solution and in the solid state, as well as functional and responsive structures.

  7. Dissolved oxygen amperometric sensor based on layer-by-layer assembly using host-guest supramolecular interactions

    International Nuclear Information System (INIS)

    The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using the host-guest binding of a supramolecular complex at a host surface by combining a self-assembled monolayer (SAM) of mono-(6-deoxy-6-mercapto)-β-cyclodextrin (βCDSH), iron (III) tetra-(N-methyl-4-pyridyl)-porphyrin (FeTMPyP) and cyclodextrin-functionalized gold nanoparticles (CDAuNP). The supramolecular modified electrode showed excellent catalytic activity for oxygen reduction. The reduction potential of oxygen was shifted about 200 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare gold electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves probably 4-electrons with a rate constant (kobs) of 7 x 104 mol-1 L s-1. A linear response range from 0.2 up to 6.5 mg L-1, with a sensitivity of 5.5 μA L mg-1 (or 77.5 μA cm-2 L mg-1) and a detection limit of 0.02 mg L-1 was obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation was 3.0% for 10 measurements of a solution of 6.5 mg L-1 oxygen.

  8. A unique quinolineboronic acid-based supramolecular structure that relies on double intermolecular B-N bonds for self-assembly in solid state and in solution

    OpenAIRE

    Zhang, Yanling; Li, Minyong; Chandrasekaran, Sekar; Gao, Xingming; Fang, Xikui; Lee, Hsiau-Wei; Hardcastle, Kenneth; Yang, Jenny; Wang, Binghe

    2007-01-01

    The boronic acid functional group plays very important roles in sugar recognition, catalysis, organic synthesis, and supramolecular assembly. Therefore, understanding the unique properties of this functional group is very important. 8-Quinolineboronic acid (8-QBA) is found to be capable of self-assembling in solid state through a unique intermolecular B-N bond mechanism reinforced by intermolecular boronic anhydride formation, π-π stacking, and hydrogen bond formation. NMR NOE and diffusion s...

  9. Electrostatic-assembly-driven formation of supramolecular rhombus microparticles and their application for fluorescent nucleic acid detection.

    Directory of Open Access Journals (Sweden)

    Hailong Li

    Full Text Available In this paper, we report on the large-scale formation of supramolecular rhombus microparticles (SRMs driven by electrostatic assembly, carried out by direct mixing of an aqueous HAuCl(4 solution and an ethanol solution of 4,4'-bipyridine at room temperature. We further demonstrate their use as an effective fluorescent sensing platform for nucleic acid detection with a high selectivity down to single-base mismatch. The general concept used in this approach is based on adsorption of the fluorescently labeled single-stranded DNA (ssDNA probe by SRM, which is accompanied by substantial fluorescence quenching. In the following assay, specific hybridization with its target to form double-stranded DNA (dsDNA results in desorption of ssDNA from SRM surface and subsequent fluorescence recovery.

  10. Supramolecular catalysis: Refocusing catalysis

    NARCIS (Netherlands)

    P.W.N.M. van Leeuwen; Z. Freixa

    2008-01-01

    This chapter contains sections titled: * Introduction: A Brief Personal History * Secondary Phosphines or Phosphites as Supramolecular Ligands * Host-Guest Catalysis * Ionic Interactions as a Means to Form Heterobidentate Assembly Ligands * Ditopic Ligands for the Construction of Bidentate Phosphine

  11. Encapsulation and Characterization of Proton-Bound Amine Homodimers in a Water Soluble, Self-Assembled Supramolecular Host

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael; Fiedler, Dorothea; Mugridge, Jeffrey; Bergman, Robert; Raymond, Kenneth

    2008-10-01

    Cyclic amines can be encapsulated in a water-soluble self-assembled supramolecular host upon protonation. The hydrogen bonding ability of the cyclic amines, as well as the reduced degrees of rotational freedom, allows for the formation of proton-bound homodimers inside of the assembly which are otherwise not observable in aqueous solution. The generality of homodimer formation was explored with small N-alkyl aziridines, azetidines, pyrrolidines and piperidines. Proton-bound homodimer formation is observed for N-alkylaziridines (R = methyl, isopropyl, tert-butyl), N-alkylazetidines (R = isopropyl, tertbutyl), and N-methylpyrrolidine. At high concentration, formation of a proton-bound homotrimer is observed in the case of N-methylaziridine. The homodimers stay intact inside the assembly over a large concentration range, thereby suggesting cooperative encapsulation. Both G3(MP2)B3 and G3B3 calculations of the proton-bound homodimers were used to investigate the enthalpy of the hydrogen bond in the proton-bound homodimers and suggest that the enthalpic gain upon formation of the proton-bound homodimers may drive guest encapsulation.

  12. Controlled Assembly of Endohedrally-Functionalized Metal-Ligand Supramolecular Complexes

    OpenAIRE

    Johnson, Amber

    2014-01-01

    An area of supramolecular chemistry that has recently been growing in popularity is the synthesis of metal-ligand cages. These are most commonly comprised of organic ligands and transition metal ions. Cage complexes often take the form of geometric polyhedra such as tetrahedra and octahedra, where the ligands act as the edges or faces and the metals serve as the vertices. Because these complexes have a polyhedral design, there is a central cavity in the cage, and this has been exploited for g...

  13. Construction of diverse supramolecular assemblies of dimetal subunits differing in coordinated water molecules via strong hydrogen bonding interactions: Synthesis, crystal structures and spectroscopic properties

    Indian Academy of Sciences (India)

    Sadhika Khullar; Sanjay K Mandal

    2014-09-01

    Three new supramolecular assemblies (constructed through strong hydrogen bonding) of [Co2(bpta)2(adc)(H2O)4](ClO4)2.2H2O (1), [Cu2(bpta)2(fum)(H2O)2](ClO4)2 (2) and [Cu2(bpta)2(tdc)(H2O) (ClO4)](ClO4).3H2O (3), which are synthesised by one pot self-assembly of the metal salt, bpta ligand and the corresponding dicarboxylate under the same reaction conditions, are reported (where adc = acetylene dicarboxylate, fum = fumarate, tdc = 2,5-thiophenedicarboxylate and bpta = N,N'-bis(2-pyridylmethyl)-tertbutylamine). These compounds have varying degrees of coordinatedwater molecules per dimetal subunits (four for 1, two for 2 and one for 3, respectively). Furthermore, the orientation of the coordinated water molecules in 1 and 2, with respect to the mono (carboxylato)-bridged dimetal subunit, is different (cis and trans, respectively). On the other hand, there is a coordinated perchlorate ion in 3 making the two metal centers inequivalent. Unlike 1 and 3, there are no lattice water molecules in 2. This difference in the dimetal subunit in 1-3 and the presence or absence of the lattice water molecules are the keys to forming the diverse supramolecular assemblies. In 1 and 3, the involvement of lattice water molecules in the construction of such assemblies is distinctly different. In case of 2, the formation of supramolecular assembly depends on the coordinated water molecule (trans to each other) and thus a ladder shaped supramolecular assembly is the result. The strength of hydrogen bonding observed in the networks of 1-3 is indicated in the O…O distances (2.596 Å to 3.160 Å) and the OH…O angles 124° to 176°. All are characterised by elemental analysis, FTIR spectroscopy and single crystal X-ray diffraction studies.

  14. Synthesis, Crystal Structure and Photocatalytic Properties of a Supramolecular Assembly Based on Keggin Polyoxotungstate

    Institute of Scientific and Technical Information of China (English)

    CHEN Shun-Yu; CHEN Xin-Qin; LIN Shen

    2012-01-01

    A new supramolecular compound (4,4'-bipyH)4[SiW12O40](4,4'-bipy) (4,4'-bipy = 4,4'-bipyridine) was synthesized hydrothermally and characterized by single-crystal X-ray diffraction and IR spectrum. The crystallography analysis for the title compound reveals that the crystal crystallizes in monoclinic, space group C2/m with a = 22.2767(12), b = 21.1879(11), c = 15.6942(8) A, β = 97.068(3)°, V = 7351.3(7) A3, Cs0H44N10040SiW12, Mr = 3659.24, Z = 4, Dc = 3.306 g/cm3, F(000) = 6544, GOOF = 1.137, R = 0.0577 and wR = 0.1579. The title compound consists of a discrete Keggin-type [SiWl2O40]4- anion, one 4,4'-bipy and four protonated (4,4'-bipyH)+ cations. The [SiWl2O40]4- anion and protonated 4,4'-bipy are connected to form a supramolecular structure by hydrogen bonds. Meanwhile, the title compound exhibits good photocatalytic activity for color degradation of Rhodamine-B dye solution under visible-light irradiation.

  15. A chiral Mn(IV) complex and its supramolecular assembly: Synthesis, characterization and properties

    Indian Academy of Sciences (India)

    Chullikkattil P Pradeep; Panthapally S Zacharias; Samar K Das

    2006-07-01

    The open air reaction of the chiral Schiff base ligand H2L, prepared by the condensation of L-phenylalaninol and 5-bromosalicylaldehyde, with MnII(CH3COO)2$\\cdot$4H2O yielded dark brown complex [MnIVL2]$\\cdot$0.5 DMF (1). Compound 1 was characterized by elemental analysis, IR, UV-visible, CD and EPR spectroscopy, cyclic voltammetry and room temperature magnetic moment determination. Singlecrystal X-ray analysis revealed that compound 1 crystallises in the monoclinic 21 space group with six mononuclear [MnIVL2] units in the asymmetric unit along with three solvent DMF molecules. In the crystal structure, each Mn(IV) complex, acting as the building unit, undergoes supramolecular linking through C-H$\\cdots$O bonds leading to an intricate hydrogen bonding network.

  16. Functionalized Nanostructures: Redox-Active Porphyrin Anchors for Supramolecular DNA Assemblies

    KAUST Repository

    Börjesson, Karl

    2010-09-28

    We have synthesized and studied a supramolecular system comprising a 39-mer DNA with porphyrin-modified thymidine nucleosides anchored to the surface of large unilamellar vesicles (liposomes). Liposome porphyrin binding characteristics, such as orientation, strength, homogeneity, and binding site size, was determined, suggesting that the porphyrin is well suited as a photophysical and redox-active lipid anchor, in comparison to the inert cholesterol anchor commonly used today. Furthermore, the binding characteristics and hybridization capabilities were studied as a function of anchor size and number of anchoring points, properties that are of importance for our future plans to use the addressability of these redox-active nodes in larger DNA-based nanoconstructs. Electron transfer from photoexcited porphyrin to a lipophilic benzoquinone residing in the lipid membrane was characterized by steady-state and time-resolved fluorescence and verified by femtosecond transient absorption. © 2010 American Chemical Society.

  17. Influence of Dissolved O2 in Organic Solvents on CuOEP Supramolecular Self-Assembly on Graphite.

    Science.gov (United States)

    Hao, Yibo; Weatherup, Robert S; Eren, Baran; Somorjai, Gabor A; Salmeron, Miquel

    2016-06-01

    The supramolecular self-assembly of copper(II) octaethylporphyrin (CuOEP) and octaethylporphyrin (H2OEP) on graphitic surfaces immersed in organic solvents (dichlorobenzene, dodecane) is studied using scanning tunneling microscopy (STM) and Raman spectroscopy. STM reveals that the self-assembled structure of CuOEP in 1,2-dichlorobenzene is significantly altered by dissolved oxygen within the solvent. Raman spectroscopy reveals that the presence of the oxygen alters the molecule-substrate interaction, which is attributed to the adsorption of oxygen on the Cu center of the CuOEP, which is facilitated by electron transfer from the graphitic surface. Such oxygen-induced changes are not observed for H2OEP, indicating that the metal center of CuOEP plays a critical role. When the solvent is dodecane, we find that solvation effects dominate. CuOEP adsorbed on graphitic surfaces provides a model system relevant to the study of the transport and activation of oxygen by enzymes and other complexes. PMID:27180868

  18. A molecular simulation probing of structure and interaction for supramolecular sodium dodecyl sulfate/single-wall carbon nanotube assemblies.

    Science.gov (United States)

    Xu, Zhijun; Yang, Xiaoning; Yang, Zhen

    2010-03-10

    Here we report a larger-scale atomic-level molecular dynamics (MD) simulation for the self-assembly of sodium dodecyl sulfate (SDS) surfactant on single-walled carbon nanotube (SWNT) surfaces and the interaction between supramolecular SDS/SWNT aggregates. We make an effort to address several important problems in regard to carbon nanotube dispersion/separation. At first, the simulation provides comprehensive direct evidence for SDS self-assembly structures on carbon nanotube surfaces, which can help to clarify the relevant debate over the exact adsorption structure. We also, for the first time, simulated the potential of mean force (PMF) between two SWNTs embedded in SDS surfactant micelles. A novel unified PMF approach has been applied to reveal various cooperative interactions between the SDS/SWNT aggregates, which is different from the previous electrostatic repulsion explanation. The unique role of sodium ions revealed here provides a new microscopic understanding of the recent experiments in the electrolyte tuning of the interfacial forces on the selective fractionation of SDS surrounding SWNTs.

  19. A versatile strategy towards non-covalent functionalization of graphene by surface-confined supramolecular self-assembly of Janus tectons

    Directory of Open Access Journals (Sweden)

    Ping Du

    2015-03-01

    Full Text Available Two-dimensional (2D, supramolecular self-assembly at surfaces is now well-mastered with several existing examples. However, one remaining challenge to enable future applications in nanoscience is to provide potential functionalities to the physisorbed adlayer. This work reviews a recently developed strategy that addresses this key issue by taking advantage of a new concept, Janus tecton materials. This is a versatile, molecular platform based on the design of three-dimensional (3D building blocks consisting of two faces linked by a cyclophane-type pillar. One face is designed to steer 2D self-assembly onto C(sp2-carbon-based flat surfaces, the other allowing for the desired functionality above the substrate with a well-controlled lateral order. In this way, it is possible to simultaneously obtain a regular, non-covalent paving as well as supramolecular functionalization of graphene, thus opening interesting perspectives for nanoscience applications.

  20. Supramolecular Au Nanoparticle Assemblies as Optical Probes for Enzyme-Linked Immunoassays

    NARCIS (Netherlands)

    Rica, de la Roberto; Velders, Aldrik H.

    2011-01-01

    A novel enzyme-linked immunoassay with nanoparticle assemblies as optical probes is presented. The macrocycle cucurbit[7]uril assembles gold nanoparticles, and the enzymatic generation of ammonium by urease as the label of the immunoassay disperses the probes to yield variations of plasmon absorbanc

  1. Reversible supramolecular assembly at specific DNA sites: nickel-promoted bivalent DNA binding with designed peptide and bipyridyl-bis(benzamidine) components.

    Science.gov (United States)

    Sánchez, Mateo I; Mosquera, Jesús; Vázquez, M Eugenio; Mascareñas, José L

    2014-09-01

    At specific DNA sites, nickel(II) salts promote the assembly of designed components, namely a bis(histidine)-modified peptide that is derived from a bZIP transcription factor and a bis(benzamidine) unit that is equipped with a bipyridine. This programmed supramolecular system with emergent properties reproduces some key characteristics of naturally occurring DNA-binding proteins, such as bivalence, selectivity, responsiveness to external agents, and reversibility.

  2. Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

    OpenAIRE

    Shawn Matthew Dirk; Jason Carl Harper; Blake Alexander Simmons; Anup Kumar Singh; Paul David Adams; Ann Mary Achyuthan; Komandoor Elayavalli Achyuthan

    2010-01-01

    Phenylpropanoid metabolism yields a mixture of monolignols that undergo chaotic, non-enzymatic reactions such as free radical polymerization and spontaneous self-assembly in order to form the polyphenolic lignin which is a barrier to cost-effective lignocellulosic biofuels. Post-synthesis lignin integration into the plant cell wall is unclear, including how the hydrophobic lignin incorporates into the wall in an initially hydrophilic milieu. Self-assembly, self-organization and aggregation gi...

  3. Supramolecular assembly of macroscopic building blocks through self-propelled locomotion by dissipating chemical energy.

    Science.gov (United States)

    Cheng, Mengjiao; Ju, Guannan; Zhang, Yingwei; Song, Mengmeng; Zhang, Yajun; Shi, Feng

    2014-10-15

    Chemical energy supplied by the catalytic decomposition of H2O2 is introduced into macroscopic building blocks, which self-propel, interact with each other, and finally assemble into ordered and advanced structures. The geometry is highly dependent on the way that the catalyst is loaded. The integration of catalyst and building block provides assembling component as well as its energy of motion. PMID:24838346

  4. Luminescent lanthanide complexes with 4-acetamidobenzoate: Synthesis, supramolecular assembly via hydrogen bonds, crystal structures and photoluminescence

    Science.gov (United States)

    Yin, Xia; Fan, Jun; Wang, Zhi Hong; Zheng, Sheng Run; Tan, Jing Bo; Zhang, Wei Guang

    2011-07-01

    Four new luminescent complexes, namely, [Eu(aba) 2(NO 3)(C 2H 5OH) 2] ( 1), [Eu(aba) 3(H 2O) 2]·0.5 (4, 4'-bpy)·2H 2O ( 2), [Eu 2(aba) 4(2, 2'-bpy) 2(NO 3) 2]·4H 2O ( 3) and [Tb 2(aba) 4(phen) 2(NO 3) 2]·2C 2H 5OH ( 4) were obtained by treating Ln(NO 3) 3·6H 2O and 4-acetamidobenzoic acid (Haba) with different coligands (4, 4'-bpy=4, 4'-bipyridine, 2, 2'-bpy=2, 2'-bipyridine, and phen=1, 10-phenanthroline). They exhibit 1D chains ( 1- 2) and dimeric structures ( 3- 4), respectively. This structural variation is mainly attributed to the change of coligands and various coordination modes of aba molecules. Moreover, the coordination units are further connected via hydrogen bonds to form 2D even 3D supramolecular networks. These complexes show characteristic emissions in the visible region at room temperature. In addition, thermal behaviors of four complexes have been investigated under air atmosphere. The relationship between the structures and physical properties has been discussed.

  5. Hollow spherical supramolecular dendrimers.

    Science.gov (United States)

    Percec, Virgil; Peterca, Mihai; Dulcey, Andrés E; Imam, Mohammad R; Hudson, Steven D; Nummelin, Sami; Adelman, Peter; Heiney, Paul A

    2008-10-01

    The synthesis of a library containing 12 conical dendrons that self-assemble into hollow spherical supramolecular dendrimers is reported. The design principles for this library were accessed by development of a method that allows the identification of hollow spheres, followed by structural and retrostructural analysis of their Pm3n cubic lattice. The first hollow spherical supramolecular dendrimer was made by replacing the tapered dendron, from the previously reported tapered dendritic dipeptide that self-assembled into helical pores, with its constitutional isomeric conical dendron. This strategy generated a conical dendritic dipeptide that self-assembled into a hollow spherical supramolecular dendrimer that self-organizes in a Pm3n cubic lattice. Other examples of hollow spheres were assembled from conical dendrons without a dipeptide at their apex. These are conical dendrons originated from tapered dendrons containing additional benzyl ether groups at their apex. The inner part of the hollow sphere assembled from the dipeptide resembles the path of a spherical helix or loxodrome and, therefore, is chiral. The spheres assembled from other conical dendrons are nonhelical, even when they contain stereocenters on the alkyl groups from their periphery. Functionalization of the apex of the conical dendrons with diethylene glycol allowed the encapsulation of LiOTf and RbOTf in the center of the hollow sphere. These experiments showed that hollow spheres function as supramolecular dendritic capsules and therefore are expected to display functions complementary to those of other related molecular and supramolecular structures. PMID:18771261

  6. Self-assembly of hydrogen-bonded supramolecular complexes of nucleic-acid-base and fatty-acid at the liquid-solid interface.

    Science.gov (United States)

    Zhao, Huiling; Song, Xin; Aslan, Hüsnü; Liu, Bo; Wang, Jianguo; Wang, Li; Besenbacher, Flemming; Dong, Mingdong

    2016-06-01

    Self-assembly provides an effective approach for the fabrication of supramolecular complexes or heterojunction materials, which have unique properties and potential applications in many fields. In this study, the self-assembled structures of stearic acid (SA) and nucleic acid base, guanine (G), are formed at the liquid-solid interface. Two main configurations, namely SA-G-SA and SA-G-G-SA, are observed and the intermolecular recognition mechanism between G and SA is proposed from the hydrogen-bonding point of view. PMID:27170421

  7. Supramolecular assembly of biological molecules purified from bovine nerve cells: from microtubule bundles and necklaces to neurofilament networks

    International Nuclear Information System (INIS)

    With the completion of the human genome project, the biosciences community is beginning the daunting task of understanding the structures and functions of a large number of interacting biological macromolecules. Examples include the interacting molecules involved in the process of DNA condensation during the cell cycle, and in the formation of bundles and networks of filamentous actin proteins in cell attachment, motility and cytokinesis. In this proceedings paper we present examples of supramolecular assembly based on proteins derived from the vertebrate nerve cell cytoskeleton. The axonal cytoskeleton in vertebrate neurons provides a rich example of bundles and networks of neurofilaments, microtubules (MTs) and filamentous actin, where the nature of the interactions, structures, and structure-function correlations remains poorly understood. We describe synchrotron x-ray diffraction, electron microscopy, and optical imaging data, in reconstituted protein systems purified from bovine central nervous system, which reveal unexpected structures not predicted by current electrostatic theories of polyelectrolyte bundling, including three-dimensional MT bundles and two-dimensional MT necklaces

  8. Eight supramolecular assemblies constructed from bis(benzimidazole) and organic acids through strong classical hydrogen bonding and weak noncovalent interactions

    Science.gov (United States)

    Jin, Shouwen; Wang, Daqi

    2014-05-01

    Eight crystalline organic acid-base adducts derived from alkane bridged bis(N-benzimidazole) and organic acids (2,4,6-trinitrophenol, p-nitrobenzoic acid, m-nitrobenzoic acid, 3,5-dinitrobenzoic acid, 5-sulfosalicylic acid and oxalic acid) were prepared and characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. Of the eight compounds five are organic salts (1, 4, 6, 7 and 8) and the other three (2, 3, and 5) are cocrystals. In all of the adducts except 1 and 8, the ratio of the acid and the base is 2:1. All eight supramolecular assemblies involve extensive intermolecular classical hydrogen bonds as well as other noncovalent interactions. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, all the complexes displayed 3D framework structure. The results presented herein indicate that the strength and directionality of the classical N+-H⋯O-, O-H⋯O, and O-H⋯N hydrogen bonds (ionic or neutral) and other nonbonding associations between acids and ditopic benzimidazoles are sufficient to bring about the formation of cocrystals or organic salts.

  9. Microphase Separation in Thin Films of Block Copolymer Supramolecular Assemblies: Composition Dependent Morphological Transitions and Molecular Architecture Effect

    Science.gov (United States)

    Nandan, Bhanu; Stamm, Manfred

    2010-03-01

    Block copolymer based supramolecular assemblies (SMAs) recently have attracted lot of attention because of their potential application as nanotemplates. These SMAs are prepared by attaching small molecules selectively to one of the blocks of the copolymer through physical interactions. In the present study, the phase behavior of SMAs formed by polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) with 2-(4'-hydroxybenzeneazo)benzoic acid (HABA) was investigated with respect to the molar ratio (X) between HABA and 4VP monomer unit in bulk as well as in thin films. It will be shown that these SMAs show some interesting composition dependent and solvent induced pathway dependent phase transitions. Moreover, the orientation of cylindrical or lamellar microdomains of P4VP(HABA) depends on the selectivity of the solvent as well as on the degree of swelling of the thin film. Furthermore, it will be shown that the molecular architecture of the block copolymer influences the orientation and ordering of microdomains in the SMA. Hence, whereas, the cylindrical and lamellar microdomains of SMA composed of a P4VP-b-PS-b-P4VP triblock copolymer were perpendicular to the substrate, those composed from a PS-b-P4VP diblock of similar composition had in-plane orientation of the microdomains.

  10. Direct Biomolecules Binding on Nonfouling Surface via Newly Discovered Supramolecular Self-assembly of Lysozyme under Physiological Condition

    Science.gov (United States)

    Yang, Peng

    2013-01-01

    A major challenge in the development of low cost and practical strategies for biomolecules immobilization on solid supports is that the multi-step chemical/physical activating and following deactivating procedures on nonfouling substrates often increase the cost and complexity of surface functional group types as well as deteriorate the surface integrity. Herein, we show a novel phase transition of lysozyme could be used to constitute a major step to address the above problem. It is found that when lysozyme is dissolved in a neutral buffer solution of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES, pH 7.4) with 1–50 mM tris(2-carboxyethyl)phosphine (TCEP) added, a fast phase transition process occurs and the resulting novel fibra-like hierarchical supramolecular assemblies made by primary spherical particles aggregation would function as a “superglue” that strongly and quickly bind onto non-fouling coatings. This binding is highly selective towards lysozyme, and excludes completely tedious synthetical, chemical/physical activation/deactivation (blocking) steps. When biotin is conjugated with lysozyme, such phase transition quickly constructs a perfect biotinylated surface on nonfouling surface for avidin binding, showing great potential for the development of low-cost and practical biochips. PMID:22707360

  11. Six hydrogen-bonded supramolecular frameworks assembled from organic acids and p-dimethylaminobenzaldehyde

    Science.gov (United States)

    Jin, Shouwen; Wang, Lanqing; Lou, Yulei; Liu, Li; Li, Bin; Li, Linyu; Feng, Chao; Liu, Hui; Wang, Daqi

    2016-03-01

    Cocrystallization of the commonly available organic compound, p-dimethylaminobenzaldehyde, with a series of organic acids gave a total of six molecular adducts with the compositions: p-dimethylaminobenzaldehyde : (3,5-dinitrosalicylic acid) [(L) · (Hdsa), Hdsa = 3,5-dinitrosalicylic acid] (1), p-dimethylaminobenzaldehyde : (3-nitrophthalic acid) [(L) · (3-H2npa), 3-H2npa = 3-nitrophthalic acid] (2), p-dimethylaminobenzaldehyde : (4-nitrophthalic acid) [(L) · (4-H2npa), 4-H2npa = 4-nitrophthalic acid] (3), p-dimethylaminobenzaldehyde : (1,5-naphthalenedisulfonic acid) : (NH3)2 [NH4 · (HL) · (nds2-) · NH3, nds- = 1,5-naphthalenedisulfonate] (4), p-dimethylaminobenzaldehyde : (oxalic acid)0.5 [(L) · (H2oa)0.5, H2oa = oxalic acid] (5), and p-dimethylaminobenzaldehyde : (fumaric acid)0.5 [(L) · (H2fum)0.5, H2fum = fumaric acid] (6). The six molecular adducts have been characterized by X-ray diffraction technique, IR, and elemental analysis, and the melting points of all adducts were also reported. And their structural and supramolecular aspects are fully analyzed. Of the six adducts, only 4 is an organic salt and the other five are cocrystals. The crystal packing is interpreted in terms of the strong classical hydrogen bonds as well as other weak non-classical hydrogen bonds. The different families of non-covalent bonds contribute to the stabilization and expansion of the total high-dimensional (2D-3D) frameworks.

  12. Self-assembled peptide nanotubes are uniquely rigid bioinspired supramolecular structures.

    Science.gov (United States)

    Kol, Nitzan; Adler-Abramovich, Lihi; Barlam, David; Shneck, Roni Z; Gazit, Ehud; Rousso, Itay

    2005-07-01

    We recently presented a novel class of self-assembled diphenylalanine-based peptide nanotubes. Here, for the first time, we present their mechanical properties, which we directly measured through indentation type experiments using atomic force microscopy. We find that the averaged point stiffness of the nanotubes is 160 N/m, and that they have a correspondingly high Young's modulus of approximately 19 GPa, as calculated by finite element analysis. This high value places these peptide nanotubes among the stiffest biological materials presently known, making them attractive building blocks for the design and assembly of biocompatible nanodevices. PMID:16178235

  13. Dragging Human Mesenchymal Stem Cells with the Aid of Supramolecular Assemblies of Single-Walled Carbon Nanotubes, Molecular Magnets, and Peptides in a Magnetic Field

    Directory of Open Access Journals (Sweden)

    Ana Cláudia C. de Paula

    2015-01-01

    Full Text Available Human adipose-derived stem cells (hASCs are an attractive cell source for therapeutic applicability in diverse fields for the repair and regeneration of damaged or malfunctioning tissues and organs. There is a growing number of cell therapies using stem cells due to their characteristics of modulation of immune system and reduction of acute rejection. So a challenge in stem cells therapy is the delivery of cells to the organ of interest, a specific site. The aim of this paper was to investigate the effects of a supramolecular assembly composed of single-walled carbon nanotubes (SWCNT, molecular magnets (lawsone-Co-phenanthroline, and a synthetic peptide (FWYANHYWFHNAFWYANHYWFHNA in the hASCs cultures. The hASCs were isolated, characterized, expanded, and cultured with the SWCNT supramolecular assembly (SWCNT-MA. The assembly developed did not impair the cell characteristics, viability, or proliferation. During growth, the cells were strongly attached to the assembly and they could be dragged by an applied magnetic field of less than 0.3 T. These assemblies were narrower than their related allotropic forms, that is, multiwalled carbon nanotubes, and they could therefore be used to guide cells through thin blood capillaries within the human body. This strategy seems to be useful as noninvasive and nontoxic stem cells delivery/guidance and tracking during cell therapy.

  14. Self-organized ureido substituted diacetylenic organogel. Photopolymerization of one-dimensional supramolecular assemblies to give conjugated nanofibers.

    Science.gov (United States)

    Dautel, Olivier J; Robitzer, Mike; Lère-Porte, Jean-Pierre; Serein-Spirau, Françoise; Moreau, Joël J E

    2006-12-20

    The introduction of the urea function as structure directing agent of diacetylene organogels (DA-OGs) has been achieved. Despite the urea function being one of the most frequently used structure directing agents for the formation of organogels, it has never been exploited in the fabrication and photopolymerization of DA-OGs. The self-association of ureas involving two hydrogen bonds is much stronger than that of urethanes or amides, and the resulting supramolecular assemblies are completely insoluble. In this context, 1,1'-(hexa-2,4-diyne-1,6-diyl)bis(3-(10-(triethoxysilyl)decyl)urea) 2 was synthesized. Compound 2 was soluble owing to the triethoxysilane function that we recently used in the fabrication of a silylated bis-urea-stilbene organogel. It formed an organogel, and its photopolymerization was studied in cyclohexane. The loss of the gel state and the formation of a red solution resulting from the polymerization were found to be the result of the constraints introduced by the urea function in close vicinity to the polymerizable function. To obtain an ureido substituted diacetylenic organogelator affording a blue highly conjugated polydiacetylene (PDA) without a sol-gel transition, a propylene spacer was introduced to move the urea function away from the polymerizable function (derivative 3). The thermochromism exhibited by the latter in the solid state was studied. Using the same setup and the same sample, UV-vis and FTIR spectra were simultaneously recorded as a function of the temperature to highlight a relation between color changes and urea association mode changes. The data showed that the reversible thermochromic transition must be associated with a reversible supramolecular modification and, conversely, that irreversible chromic transitions are the result of irreversible structural modifications. The chromic effects of the acidic hydrolysis-polycondensation of the trialkoxysilyl groups to form a siloxane network were studied on a thin film of 3. In

  15. Supramolecular self-assembly of metal- free naphthalocyanine on Au(111)

    NARCIS (Netherlands)

    Pham, Tuan Anh; Song, Fei; Stöhr, Meike

    2014-01-01

    The self-assembly of metal-free naphthalocyanine (H(2)Nc) on the Au(111) surface is studied under ultrahigh vacuum conditions at room temperature using a combination of scanning tunnelling microscopy (STM), low-energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). The STM me

  16. The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c, d, or e mimics.

    Science.gov (United States)

    Jochum, Tobias; Reddy, Chilla Malla; Eichhöfer, Andreas; Buth, Gernot; Szmytkowski, Jedrzej; Kalt, Heinz; Moss, David; Balaban, Teodor Silviu

    2008-09-01

    Bacteriochlorophylls (BChls) c, d, and e are the main light-harvesting pigments of green photosynthetic bacteria that self-assemble into nanostructures within the chlorosomes forming the most efficient antennas of photosynthetic organisms. All previous models of the chlorosomal antennae, which are quite controversially discussed because no single crystals could be grown so far from these organelles, involve a strong hydrogen-bonding interaction between the 3(1) hydroxyl group and the 13(1) carbonyl group. We have synthesized different self-assemblies of BChl c mimics having the same functional groups as the natural counterparts, that is, a hydroxyethyl substituent, a carbonyl group and a divalent metal atom ligated by a tetrapyrrole. These artificial BChl mimics have been shown by single crystal x-ray diffraction to form extended stacks that are packed by hydrophobic interactions and in the absence of hydrogen bonding. Time-resolved photoluminescence proves the ordered nature of the self-assembled stacks. FT-IR spectra show that on self-assembly the carbonyl frequency is shifted by approximately 30 cm(-1) to lower wavenumbers. From the FT-IR data we can infer the proximal interactions between the BChls in the chlorosomes consistent with a single crystal x-ray structure that shows a weak electrostatic interaction between carbonyl groups and the central zinc atom. PMID:18755898

  17. Supramolecular nanostructuring of silver surfaces via self-assembly of [60]fullerene and porphyrin modules

    NARCIS (Netherlands)

    Bonifazi, Davide; Kiebele, Andreas; Stöhr, Meike; Cheng, Fuyong; Jung, Thomas; Diederich, Francois; Spillmann, Hannes

    2007-01-01

    Recent achievements in our laboratory toward the "bottom-up" fabrication of addressable multicomponent molecular entities obtained by self-assembly of C-60 and porphyrins on Ag(100) and Ag(111) surfaces are described.. Scanning tunneling microscopy (STM) studies on ad-layers constituting monomeric a

  18. Assembling and releasing performance of supramolecular hydrogels formed from simple drug molecule as the hydrogelator

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simple drug compound, 4-oxo-4-(2-pyridinylamino) butanoic acid (defined as AP), was able to gel water at 4 wt%concentration under various conditions. In the superstructure, AP molecules assembled into fibrous aggregates driving by hydrogen bonds and π-π stacking interaction. The gels with different backbone structures released drug molecules in different speeds.

  19. Exploring the Transferability of Large Supramolecular Assemblies to the Vacuum-Solid Interface

    DEFF Research Database (Denmark)

    Xu, W.; Dong, M. D.; Gersen, H.;

    2009-01-01

    We present an interplay of high-resolution scanning tunneling microscopy imaging and the corresponding theoretical calculations based on elastic scattering quantum chemistry techniques of the adsorption of a gold-functionalized rosette assembly and its building blocks on a Au(111) surface...

  20. Supramolecular Photochemistry Controlling Photochemical Processes

    CERN Document Server

    Ramamurthy, V

    2011-01-01

    This is the most updated, comprehensive collection of monographs on all aspects of photochemistry and photophysics related to natural and synthetic, inorganic, organic, and biological supramolecular systems. Supramolecular Photochemistry: Controlling Photochemical Processes addresses reactions in crystals, organized assemblies, monolayers, zeolites, clays, silica, micelles, polymers, dendrimers, organic hosts, supramolecular structures, organic glass, proteins and DNA, and applications of photosystems in confined media. This landmark publication describes the past, present, and future of this

  1. Self-assembled supramolecular nano vesicles for safe and highly efficient gene delivery to solid tumors

    Directory of Open Access Journals (Sweden)

    Li W

    2012-08-01

    Full Text Available Wei Li,1,2,* Huafei Li,1,* Jinfeng Li,1,* Huajing Wang,1,* He Zhao,1 Li Zhang,1 Yu Xia,1 Zengwei Ye,1 Jie Gao,1,2 Jianxin Dai,1–3 Hao Wang,1–3 Yajun Guo1–31International Joint Cancer Institute, The Second Military Medical University, Shanghai, 2National Engineering Research Center for Antibody Medicine, State Key Laboratory of Antibody Medicine and Targeting Therapy and Shanghai Key Laboratory of Cell Engineering, Shanghai, 3PLA General Hospital Cancer Center, PLA Graduate School of Medicine, Beijing, People's Republic of China*These authors contributed equally to this workAbstract: The main obstacles for cationic polyplexes in gene delivery are in vivo instability and low solid-tumor accumulation. Safe vectors with high transfection efficiency and in vivo tumor accumulation are therefore highly desirable. In this study, the amphiphilic block copolymer poly(n-butyl methacrylate-b-poly(N-acryloylmorpholine was synthesized by reversible addition–fragmentation chain-transfer (RAFT radical polymerization. The corresponding well-defined vesicles with narrow size distribution were tailored by finely regulating the packing parameter (β of copolymer (1/2 < β < 1. Compared with traditional "gold-standard" polycation (polyethylenimine, 25 kDa, plasmid DNA condensing efficiency, DNase I degradation protection, and cellular uptake were improved by the supramolecular nano vesicles. In addition, the plasmid DNA transferring efficiency in 10% fetal bovine serum medium was enlarged five times to that of polyethylenimine in renal tubular epithelial and human hepatocellular carcinoma cell lines. This improved in vitro transfection was mainly attributed to the densely packed bilayer. This stealth polyplex showed high serum stability via entropic repulsion, which further protected the polyplex from being destroyed during sterilization. As indicated by the IVIS® Lumina II Imaging System (Caliper Life Sciences, Hopkinton, MA 24 hours post

  2. Hierarchical Self-Assembly of Polyoxometalate-Based Hybrids Driven by Metal Coordination and Electrostatic Interactions: From Discrete Supramolecular Species to Dense Monodisperse Nanoparticles.

    Science.gov (United States)

    Izzet, Guillaume; Abécassis, Benjamin; Brouri, Dalil; Piot, Madeleine; Matt, Benjamin; Serapian, Stefano Artin; Bo, Carles; Proust, Anna

    2016-04-20

    The metal-driven self-assembly processes of a covalent polyoxometalate (POM)-based hybrid bearing remote terpyridine binding sites have been investigated. In a strongly dissociating solvent, a discrete metallomacrocycle, described as a molecular triangle, is formed and characterized by 2D diffusion NMR spectroscopy (DOSY), small-angle X-ray scattering (SAXS), and molecular modeling. In a less dissociating solvent, the primary supramolecular structure, combining negatively charged POMs and cationic metal linkers, further self-assemble through intermolecular electrostatic interactions in a reversible process. The resulting hierarchical assemblies are dense monodisperse nanoparticles composed of ca. 50 POMs that were characterized by SAXS and transmission electron microscopy (TEM). This multiscale organized system directed by metal coordination and electrostatic interactions constitutes a promising step for the future design of POM self-assemblies with controllable structure-directing factors. PMID:27019075

  3. Experimental and theoretical analysis of H-bonded supramolecular assemblies of PTCDA molecules

    OpenAIRE

    Mura, M; X. Sun; F. Silly; Jonkman, H. T.; Briggs, G. A. D.; Castell, M. R.; Kantorovich, L. N.

    2010-01-01

    Using a systematic method based on considering all possible hydrogen bond connections between molecules and subsequent density-functional theory (DFT) calculations, we investigated planar superstructures that the perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) molecules can form in one and two dimensions. Structures studied are mostly based on two molecule unit cells and all assemble in flat periodic arrays. We show that 42 different monolayer structures are possible, which can...

  4. Yielding and flow of solutions of thermoresponsive surfactant tubes: tuning macroscopic rheology by supramolecular assemblies

    OpenAIRE

    Fameau, Anne-Laure; Saint-Jalmes, Arnaud

    2014-01-01

    International audience In this article, we show that stimuli-induced microscopic transformations of self-assembled surfactant structures can be used to tune the macroscopic bulk and interfacial rheological properties. Previously, we had described the formation of micron-sized 12-hydroxystearic acid tubes having a temperaturetunable diameter in the bulk, and also adsorbing at the air-water interface. We report now a detailed study of the bulk and interfacial rheological properties of this s...

  5. Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials

    Directory of Open Access Journals (Sweden)

    Valeria C. Edelsztein

    2013-09-01

    Full Text Available Supramolecular gels are an important and interesting class of soft materials that show great potential for many applications. Most of them have been discovered serendipitously, and understanding the supramolecular self-assembly that leads to the formation of the gel superstructure is the key to the directed design of new organogels. We report herein the organogelating property of four stereoisomers of the simple steroid 2,3-dihydroxycholestane. Only the isomer with the trans-diaxial hydroxy groups had the ability to gelate a broad variety of liquids and, thus, to be a super-organogelator for hydrocarbons. The scope of solvent gelation was analysed with regard to two solvent parameters, namely the Kamlet–Taft and the Hansen solubility parameters. The best correlation was observed with the Hansen approach that revealed the existence of two clear gelation zones. We propose a general model of self-assembly through multiple intermolecular hydrogen bonds between the 1,2-dihydroxy system, which is based on experimental data and computational simulations revealing the importance of the di-axial orientation of the hydroxy groups for the one-dimensional self-assembly. Under controlled conditions, the fibrillar superstructure of the organogel was successfully used as a template for the in-situ sol–gel polymerization of tetraethoxysilane and the further preparation of silica nanotubes. We propose that the driving forces for templating are hydrogen bonding and electrostatic interactions between the anionic silicate intermediate species and the self-assembled fibrillar network.

  6. Amelogenin, an extracellular matrix protein, in the treatment of venous leg ulcers and other hard-to-heal wounds: Experimental and clinical evidence  ||FREE PAPER||

    Directory of Open Access Journals (Sweden)

    Marco Romanelli

    2008-06-01

    Full Text Available Marco Romanelli1, Valentina Dini1, Peter Vowden2, Magnus S Ågren31Department of Dermatology, University of Pisa, Pisa, Italy; 2Vascular Unit, Bradford Royal Infirmary, Bradford, United Kingdom; 3Department of Surgery K, Bispebjerg Hospitals, Copenhagen University Hospital, Copenhagen, DenmarkAbstract: Amelogenins are extracellular matrix proteins that, under physiological conditions, self-assemble into globular aggregates up to micron-sizes. Studies with periodontal fibroblasts indicate that attachment to these structures increases the endogenous secretion of multiple growth factors and cell proliferation. Pre-clinical and clinical studies indicate that cutaneous wounds benefit from treatment with amelogenins. A randomized controlled trial (RCT involving patients with hard-to-heal venous leg ulcers (VLUs (ie, ulcers with a surface area ≥10 cm2 and duration of ≥6 months showed that the application of amelogenin (Xelma®, Molnlycke Health Care, Gothenburg, Sweden as an adjunct treatment to compression results in significant reduction in ulcer size, improvement in the state of ulcers, reduced pain, and a larger proportion of ulcers with low levels of exudate, compared with treatment with compression alone. Amelogenin therapy was also shown to be safe to use in that there were no significant differences in adverse events noted between patients treated with amelogenin plus compression and those treated with compression alone. Case study evaluations indicate that the benefits of amelogenin therapy demonstrated in the RCT are being repeated in “real life” situations and that amelogenin therapy may also have a role to play in the treatment of other wound types such as diabetic foot ulcers.Keywords: extracellular matrix, amelogenin, venous leg ulcers, diabetic foot ulcers, pyoderma gangrenosum

  7. Supramolecular self-assembly of metal- free naphthalocyanine on Au(111)

    OpenAIRE

    Pham, Tuan Anh; Song, Fei; Stöhr, Meike

    2014-01-01

    The self-assembly of metal-free naphthalocyanine (H(2)Nc) on the Au(111) surface is studied under ultrahigh vacuum conditions at room temperature using a combination of scanning tunnelling microscopy (STM), low-energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). The STM measurements reveal that the molecules form a well-ordered, defect-free structure with a square-like unit cell at monolayer coverage with their molecular plane parallel to the substrate plane. The mo...

  8. Supramolecular chemistry and technology

    Directory of Open Access Journals (Sweden)

    HENRIQUE E. TOMA

    2000-03-01

    Full Text Available Supramolecular chemistry deals with the association of several chemical species, in an organized way and according to well defined purposes. Based on a molecular engineering approach, supramolecular structures can be designed from pre-formed building blocks, providing a promising route from chemistry to molecular nanotechnology. New supramolecular systems have been assembled in our laboratory with the use of bridging unities such as tetrapyridylporphyrins, porphyrazines and polypyrazines, connecting transition metal complexes and clusters. These systems display a very exciting electrochemical and catalytic behavior, and interact with DNA, generating ¹O2 and leading to efficient oxidative clivage for photodynamic terapy applications. Molecular interfaces have been developed, exhibiting photocurrent response in the presence of visible-UV light, and rectifying properties in the presence of electroactive species. Successful applications of the supramolecular species in chemical and bio-sensors have been developed.

  9. Enantiomeric Excess-Tuned 2D Structural Transition: From Heterochiral to Homochiral Supramolecular Assemblies.

    Science.gov (United States)

    Li, Shu-Ying; Chen, Ting; Wang, Lin; Sun, Bing; Wang, Dong; Wan, Li-Jun

    2016-07-12

    Spontaneous resolution of enantiomers is an intriguing and important phenomenon in surface chirality studies. Herein, we report on a two-dimensional (2D) structural transition from the heterochiral to homochiral assembly tuned by changing the enantiomeric excess (ee) of enantiomers in the solution phase. Enantiomers cocrystallize as racemates on the surface when the ee of the R-enantiomer (or S-enantiomer) remains below a critical value, whereas chiral segregation is achieved, and globally homochiral surfaces composed of exclusively one enantiomer are obtained as the critical ee is exceeded. The heterochiral-homochiral transition is ascribed to the formation of energetically unfavored homochiral molecular dimers under the control of the majority-rules principle at high ee values. Such results present an intriguing phenomenon in chiral ordering at surfaces, promising a new enlightenment toward understanding chiral resolution and the evolution of chirality. PMID:27287273

  10. Supramolecular Chemistry And Self-assembly Special Feature: Virus-assisted loading of polymer nanocontainer

    Science.gov (United States)

    Graff, Alexandra; Sauer, Marc; van Gelder, Patrick; Meier, Wolfgang

    2002-04-01

    We present a DNA-containing polymeric nanocontainer using the self-assembled superstructure of amphiphilic block copolymers in aqueous solutions. To demonstrate that DNA translocation is possible across a completely synthetic block copolymer membrane, we have used a phage transfection strategy as a DNA-transfer model system. For this purpose the bacterial channel forming protein LamB was reconstituted in ABA-triblock copolymer vesicles. The outer membrane protein LamB is a specific transporter for maltodextrins but also serves as a receptor for phage to trigger the ejection of phage DNA. We demonstrate that the functionality of the LamB protein is fully preserved despite the artificial surrounding. This leads to a type of polymeric vehicle for DNA that could be useful for gene therapy.

  11. Supramolecular Coordination Assemblies Constructed From Multifunctional Azole-Containing Carboxylic Acids

    Directory of Open Access Journals (Sweden)

    Yuheng Deng

    2010-05-01

    Full Text Available This paper provides a brief review of recent progress in the field of metal coordination polymers assembled from azole-containing carboxylic acids and gives a diagrammatic summary of the diversity of topological structures in the resulting infinite metal-organic coordination networks (MOCNs. Azole-containing carboxylic acids are a favorable kind of multifunctional ligand to construct various metal complexes with isolated complexes and one, two and three dimensional structures, whose isolated complexes are not the focus of this review. An insight into the topology patterns of the infinite coordination polymers is provided. Analyzed topologies are compared with documented topologies and catalogued by the nature of nodes and connectivity pattern. New topologies which are not available from current topology databases are described and demonstrated graphically.

  12. Supramolecular Cationic Assemblies against Multidrug-Resistant Microorganisms: Activity and Mechanism of Action

    Directory of Open Access Journals (Sweden)

    Letícia Dias de Melo Carrasco

    2015-03-01

    Full Text Available The growing challenge of antimicrobial resistance to antibiotics requires novel synthetic drugs or new formulations for old drugs. Here, cationic nanostructured particles (NPs self-assembled from cationic bilayer fragments and polyelectrolytes are tested against four multidrug-resistant (MDR strains of clinical importance. The non-hemolytic poly(diallyldimethylammonium chloride (PDDA polymer as the outer NP layer shows a remarkable activity against these organisms. The mechanism of cell death involves bacterial membrane lysis as determined from the leakage of inner phosphorylated compounds and possibly disassembly of the NP with the appearance of multilayered fibers made of the NP components and the biopolymers withdrawn from the cell wall. The NPs display broad-spectrum activity against MDR microorganisms, including Gram-negative and Gram-positive bacteria and yeast.

  13. Supramolecular Assemblies of Poly(propyleneimine) Dendrimers Driven by Simple Monovalent Counterions

    Science.gov (United States)

    Eghtesadi, Seyed Ali; Haso, Fadi; Kashfipour, Marjan Alsadat; Lillard, Robert, , Dr.; Liu, Tianbo, , Dr.; Tianbo Liu's group Team, Dr.; Lillard's group Collaboration, Dr.

    Polyelectrolytes (PE) are fascinating class of polymers carrying dissociative ionic groups which give them unique properties in solutions and at charged surfaces. The properties of these polymers in solution are mainly depending on the fraction of dissociated ionic groups, the quality of solvent and salt concentration. Describing the solution properties of polyelectrolytes have always been an obstacle for polymer scientists due to their different behavior as a result of their dual character of being highly charged electrolytes and at macromolecular size. The question we tried to address was what happens to solution behavior of charged polyelectrolytes when they reach to the nano-scale size which can neither be considered as point charges nor colloids. Second generation of poly(propyleneimine) dendrimer in different solvent qualities, salt concentrations, pH and temperatures were studied using techniques such as LLS, TEM, AFM and zeta-potential, and dominant controlling factors over their self-assembly into hollow spherical ``Blackberry'' like nanoparticles was investigated.

  14. Altering the inclusion properties of CTV through crystal engineering: CTV, carborane, and DMF supramolecular assemblies

    Science.gov (United States)

    Hardie; Raston; Wells

    2000-09-01

    The complexes [Na(CTV)2(OH)(H2O)](H2O)(DMF)2(o-carborane) (3; CTV = cyclotriveratrylene), [K(OH)(CTV)(DMF)]2(o-carborane) (4), [(DMF)(CTV)]2(H2O)4(o-carborane) (5), and (o-carborane)(CTV)(DMF)2 (6) all form as crystalline inclusion complexes from N,N'-dimethylformamide (DMF) solution. Complexes 3 and 4 are the first reported examples of CTV acting as a chelating ligand, with two CTV molecules coordinating cis to the six-coordinate M+ centers (M=Na, K). The extended structures of complexes 3-5 are similar, forming extended coordinate and/or hydrogen-bonding interactions and all feature intracavity complexation of DMF by CTV, while the complex 6 forms an assembly of (o-carborane) intersection of two sets (CTV) ball-and-socket supermolecules with DMF as a channel-type included guest. PMID:11003008

  15. The physical properties of supramolecular peptide assemblies: from building block association to technological applications.

    Science.gov (United States)

    Adler-Abramovich, Lihi; Gazit, Ehud

    2014-01-01

    Bio-inspired nano-materials can be formed by the ordered assembly of elementary building blocks using recognition modules and structural elements. Among the biological sources, peptides and proteins are of special interest due to their role as major structural elements in all living systems, ranging from bacteria to humans in a continuum of magnitudes, from the nano-scale to the macro-scale. Peptides, as short as dipeptides, contain all the molecular information needed to form well-ordered structures at the nano-scale. Here, in light of the significant advancements in the field of peptide nanostructures in the last few years, we provide an updated overview of this subject. The use of these nanostructures was indeed recently demonstrated in various fields including the design of molecular motors based on nanostructure complexation with a metal-organic framework, the delivery of therapeutic agents, the development of energy storage devices and the fabrication of piezoelectric-based sensors. PMID:25099656

  16. 环糊精相关的超分子自组装最新进展%Recent Progress in Supramolecular Self-Assembly Based on Cyclodextrin

    Institute of Scientific and Technical Information of China (English)

    周冬香; 孙涛; 邓维

    2012-01-01

    The supramolecular material has been widely used as a type of drug/gene delivery, molecule device, molecule sensor and catalysis. Due to their excellent biologic and optical properties, cyclodextrins have recently attracted increasingly more attention. In this review the newest development of the supramolecular self-assembly based on cyclodextrin is summarized. The article provided detail information about the synthesis and applications of both of rotaxanes formed by cyclodextrin ring and polymer axes, and supramolecular polymer without polymer backbone.%对基于环糊精的超分子自组装的最新研究进展作了综述.详细介绍了环糊精为轮、高分子为轴的聚轮烷的制备及其修饰的方法,同时还介绍了无高分子参与的环糊精的超分子自组装高分子化合物的制备.并且对这些超分子在智能材料、生物医药和聚合催化等方面的应用进行了介绍.

  17. Supramolecular Self-Assembly of Histidine-Capped-Dialkoxy-Anthracene: A Visible Light Triggered Platform for facile siRNA Delivery

    KAUST Repository

    Patil, Sachin

    2016-06-29

    Supramolecular self-assembly of histidine-capped-dialkoxy-anthracene (HDA) results in the formation of light responsive nanostructures.Single-crystal X-ray diffraction analysis of HDA shows two types of hydrogen bonding. The first hydrogen bond is established between the imidazole moieties while the second involves the oxygen atom of one amide group and the hydrogen atom of a second amide group. When protonated in acidic aqueous media, HDA successfully complexes siRNA yielding spherical nanostructures. This biocompatible platform controllably delivers siRNA with high efficacy upon visible light irradiation leading up to 90% of gene silencing in live cells.

  18. Explosive decomposition of a melamine-cyanuric acid supramolecular assembly for fabricating defect-rich nitrogen-doped carbon nanotubes with significantly promoted catalysis.

    Science.gov (United States)

    Zhao, Zhongkui; Dai, Yitao; Ge, Guifang; Wang, Guiru

    2015-05-26

    A facile and scalable approach for fabricating structural defect-rich nitrogen-doped carbon nanotubes (MCSA-CNTs) through explosive decomposition of melamine-cyanuric acid supramolecular assembly is presented. In comparison to pristine carbon nanotubes, MCSA-CNT exhibits significantly enhanced catalytic performance in oxidant- and steam-free direct dehydrogenation of ethylbenzene, demonstrating the potential for metal-free clean and energy-saving styrene production. This finding also opens a new horizon for preparing highly-efficient carbocatalysts rich in structural defect sites for diverse transformations. PMID:25900736

  19. A biocompatible cobaltporphyrin-based complex micelle constructed via supramolecular assembly for oxygen transfer.

    Science.gov (United States)

    Shen, Liangliang; Qu, Rui; Shi, Hejin; Huang, Fan; An, Yingli; Shi, Linqi

    2016-05-26

    Herein, a complex micelle as an oxygen nano-carrier is constructed through the hierarchical assembly of the diblock copolymer poly(ethylene glycol)-block-poly(l-lysine) (PEG-b-PLys), tetrakis(4-sulfonatophenyl)porphinato cobalt(ii) (Co(ii)TPPS), a heptapeptide (Cys-His-His-His-His-His-His) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CD). Co(ii)TPPS was encapsulated into the cavities of TM-β-CDs driven by the host-guest interaction so that the irreversible formation of a μ-oxo-dimer of Co(ii)TPPS can be effectively prevented. The imidazole groups of the heptapeptide were selected as good axial ligands coordinating to the centric cobalt of Co(ii)TPPS, which subtly constituted the five-coordinated precursor serving as an active functional centre for oxygen binding. The sixth position of Co(ii)TPPS can bind oxygen. Furthermore, the host-guest inclusion (TM-β-CD/Co(ii)TPPS) was loaded into the hydrophobic core of the complex micelle and tightly fixed with PLys chains. The hydrophilic PEG blocks stretched in the aqueous solution constitute the shells which stabilize the structure of the complex micelle as well as impart the complex micelle sufficient blood circulation time. Moreover, the complex micelle exhibited excellent biocompatibility and cellular uptake. Therefore, the rationally designed amphiphilic structure can work as promising artificial O2 carriers in vivo. Potentially, the complex micelle can be expected to change the anaerobic microenvironment and find applications in the repair of the cells damaged by cellular hypoxia. PMID:27009911

  20. Supramolecular recognition of heteropairs of lanthanide ions: a step toward self-assembled bifunctional probes.

    Science.gov (United States)

    André, Nicolas; Jensen, Thomas B; Scopelliti, Rosario; Imbert, Daniel; Elhabiri, Mourad; Hopfgartner, Gérard; Piguet, Claude; Bünzli, Jean-Claude G

    2004-01-26

    Three unsymmetrical ditopic hexadentate ligands coded for the recognition of trivalent lanthanide ions have been synthesized, L(AB), L(AC), and L(BC), where A represents a benzimidazole-pyridine-benzimidazole coordination unit, B a benzimidazole-pyridine-carboxamide one, and C a benzimidazole-pyridine-carboxylic acid moiety. Under stoichiometric 2:3 (Ln:L) conditions, these ligands self-assemble with lanthanide ions to yield triple-stranded bimetallic helicates having a sizable stability in acetonitrile: log beta(23) values for Eu are equal to 23.9 +/- 0.5 (L(AB)), 23.3 +/- 0.7 (deprotonated L(AC)), and 29.8 +/- 0.5 (deprotonated L(BC)). The crystal structure of the EuEu helicate with L(AB) shows 9-coordinate metal ions and an HHH (H stands for head) configuration of the helically wrapped ligand strands. In the presence of equimolar quantities of Ln and Ln' ions, L(AB) displays a remarkable predisposition to form HHH-heterobimetallic edifices, as proved both in the solid state by the crystal structures of the LaEu, LaTb, PrEr, and PrLu helicates and in solution by NMR spectroscopy. In all cases, the benzimidazole-pyridine-carboxamide units of the three ligands are bound to the smaller lanthanide ion, a fact further ascertained by high-resolution luminescence data on LaEu and by (1)H NMR. Analysis of the lanthanide-induced (1)H NMR shifts and of the spin-lattice relaxation times of the [LnLu(L(AB))(3)](6+) series (Ln = Ce, Pr, Nd, Sm, Eu) demonstrates the isostructural nature of the complexes in solution and that the crystal structure of LaTb is a good model for the solution structure. The selectivity of L(AB) for heteropairs of Ln(III) ions increases with increasing difference in ionic radius, resulting in 70% of the heterobimetallic species for deltar(i) = 0.1 A and up to 90% for LaLu (deltar(i) = 0.18 A), and corresponding to delta(deltaG) in the range 3-10 kJ.mol(-)(1). The origins of this stabilization are discussed in terms of the donor properties of the

  1. 新型超分子化合物的合成自组装及应用研究的新进展%Recent Research Achievements on Synthesis,Self-assembly and Applications of New Supramolecular Compounds

    Institute of Scientific and Technical Information of China (English)

    张来新; 胡小兵

    2014-01-01

    This paper briefly introduced the definition, concept, generation and application of supramolecular chemistry. Emphases were put on three parts:① synthesis and self-assembly of new supramolecular compounds;② synthesis and selective recognition effects of new supramolecular compounds;③synthesis and application of su-pramolecular crown ether metal complexes.%简要介绍了超分子化学的定义、概念、产生及应用,详细介绍了:①新型超分子化合物合成及自组装;②新型超分子化合物的合成及选择性识别作用;③超分子冠醚金属配合物的合成及应用。

  2. Neutron Reflectometry Studies of the Adsorbed Structure of the Amelogenin, LRAP

    Energy Technology Data Exchange (ETDEWEB)

    Tarasevich, Barbara J.; Perez-Salas, Ursula; Masica, David L.; Philo, John; Krueger, Susan; Majkrzak, Charles F.; Gray, Jeffrey J.; Shaw, Wendy J.

    2013-03-21

    Amelogenins make up over 90 percent of the protein present during enamel formation and have been demonstrated to be critical in proper enamel development, but the mechanism governing this control is not well understood. Leucine-rich amelogenin peptide (LRAP) is a 59-residue splice variant of amelogenin and contains the charged regions from the full protein thought to control crystal regulation. In this work, we utilized neutron reflectivity (NR) to investigate the structure and orientation of LRAP adsorbed from solutions onto molecularly smooth COOH-terminated self-assembled monolayers (SAMs) surfaces. Sedimentation velocity experiments revealed that LRAP is primarily a monomer in saturated calcium phosphate (SCP) solutions (0.15 M NaCl) at pH 7.4. LRAP adsorbed as ~33 Å thick layers at ~70% coverage as determined by NR. Rosetta simulations of the dimensions of LRAP in solution (37 Å diameter) indicate that the NR determined z dimension is consistent with an LRAP monomer. Sedimentation velocity experiments and Rosetta simulation show that the LRAP monomer has an extended, asymmetric shape in solution. The NR data suggests that the protein is not completely extended on the surface, having some degree of structure away from the surface. A protein orientation with the C-terminal and inner N-terminal region (~8-24)) located near the surface is consistent with the higher scattering length density (SLD) and higher protein hydration found near the surface by NR. This work presents new information on the tertiary and quaternary structure of LRAP in solution and adsorbed onto surfaces. It also presents further evidence that the monomeric species may be an important functional form of amelogenin proteins.

  3. Surface-Confined Supramolecular Self-Assembly of Molecular Nanocranes for Chemically Lifting and Positioning C60 above a Conducting Substrate.

    Science.gov (United States)

    Du, Ping; Kreher, David; Mathevet, Fabrice; Maldivi, Pascale; Charra, Fabrice; Attias, André-Jean

    2015-12-21

    2D supramolecular self-assembly is a good way to form well-defined nanostructures on various substrates. One of the current challenges is to extend this approach to 3D functional building blocks. Here, we address this issue by providing a strategy for the controlled lifting and positioning of functional units above a graphitic substrate. This is the first time that multistory cyclophane-based 3D tectons incorporating C60 units have been designed and synthesized. Molecular modelling provides a description of the 3D geometries and evidences the flexible character of the building blocks. Despite this later feature, the supramolecular self-assembly of Janus tectons on HOPG yields well-ordered adlayers incorporating C60 arrays at well-defined mean distances from the surface. As our approach is not limited to C60 , the results reported here open-up possibilities for applications where the topological and electronic interactions between the substrate and the functional unit are of prime importance.

  4. Patchy Supramolecular Bottle-Brushes Formed by Solution Self-Assembly of Bis(urea)s and Tris(urea)s Decorated by Two Incompatible Polymer Arms.

    Science.gov (United States)

    Catrouillet, Sylvain; Bouteiller, Laurent; Boyron, Olivier; Lorthioir, Cédric; Nicol, Erwan; Pensec, Sandrine; Colombani, Olivier

    2016-09-01

    In an attempt to design urea-based Janus nanocylinders through a supramolecular approach, nonsymmetrical bis(urea)s and tris(urea)s decorated by two incompatible polymer arms, namely, poly(styrene) (PS) and poly(isobutylene) (PIB), were synthesized using rather straightforward organic and polymer chemistry techniques. Light scattering experiments revealed that these molecules self-assembled in cyclohexane by cooperative hydrogen bonds. The extent of self-assembly was limited for the bis(urea)s. On the contrary, reasonably anisotropic 1D structures (small nanocylinders) could be obtained with the tris(urea)s (Nagg ∼ 50) which developed six cooperative hydrogen bonds per molecule. (1)H transverse relaxation measurements and NOESY NMR experiments in cyclohexane revealed that perfect Janus nanocylinders with one face consisting of only PS and the other of PIB were not obtained. Nevertheless, phase segregation between the PS and PIB chains occurred to a large extent, resulting in patchy cylinders containing well separated domains of PIB and PS chains. Reasons for this behavior were proposed, paving the way to improve the proposed strategy toward true urea-based supramolecular Janus nanocylinders.

  5. Engineering of supramolecular photoactive protein architectures: the defined co-assembly of photosystem I and cytochrome c using a nanoscaled DNA-matrix.

    Science.gov (United States)

    Stieger, Kai R; Ciornii, Dmitri; Kölsch, Adrian; Hejazi, Mahdi; Lokstein, Heiko; Feifel, Sven C; Zouni, Athina; Lisdat, Fred

    2016-05-19

    The engineering of renewable and sustainable protein-based light-to-energy converting systems is an emerging field of research. Here, we report on the development of supramolecular light-harvesting electrodes, consisting of the redox protein cytochrome c working as a molecular scaffold as well as a conductive wiring network and photosystem I as a photo-functional matrix element. Both proteins form complexes in solution, which in turn can be adsorbed on thiol-modified gold electrodes through a self-assembly mechanism. To overcome the limited stability of self-grown assemblies, DNA, a natural polyelectrolyte, is used as a further building block for the construction of a photo-active 3D architecture. DNA acts as a structural matrix element holding larger protein amounts and thus remarkably improving the maximum photocurrent and electrode stability. On investigating the photophysical properties, this system demonstrates that effective electron pathways have been created.

  6. Engineering of supramolecular photoactive protein architectures: the defined co-assembly of photosystem I and cytochrome c using a nanoscaled DNA-matrix

    Science.gov (United States)

    Stieger, Kai R.; Ciornii, Dmitri; Kölsch, Adrian; Hejazi, Mahdi; Lokstein, Heiko; Feifel, Sven C.; Zouni, Athina; Lisdat, Fred

    2016-05-01

    The engineering of renewable and sustainable protein-based light-to-energy converting systems is an emerging field of research. Here, we report on the development of supramolecular light-harvesting electrodes, consisting of the redox protein cytochrome c working as a molecular scaffold as well as a conductive wiring network and photosystem I as a photo-functional matrix element. Both proteins form complexes in solution, which in turn can be adsorbed on thiol-modified gold electrodes through a self-assembly mechanism. To overcome the limited stability of self-grown assemblies, DNA, a natural polyelectrolyte, is used as a further building block for the construction of a photo-active 3D architecture. DNA acts as a structural matrix element holding larger protein amounts and thus remarkably improving the maximum photocurrent and electrode stability. On investigating the photophysical properties, this system demonstrates that effective electron pathways have been created.The engineering of renewable and sustainable protein-based light-to-energy converting systems is an emerging field of research. Here, we report on the development of supramolecular light-harvesting electrodes, consisting of the redox protein cytochrome c working as a molecular scaffold as well as a conductive wiring network and photosystem I as a photo-functional matrix element. Both proteins form complexes in solution, which in turn can be adsorbed on thiol-modified gold electrodes through a self-assembly mechanism. To overcome the limited stability of self-grown assemblies, DNA, a natural polyelectrolyte, is used as a further building block for the construction of a photo-active 3D architecture. DNA acts as a structural matrix element holding larger protein amounts and thus remarkably improving the maximum photocurrent and electrode stability. On investigating the photophysical properties, this system demonstrates that effective electron pathways have been created. Electronic supplementary information

  7. Carbohydrates in Supramolecular Chemistry.

    Science.gov (United States)

    Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

    2016-02-24

    Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed. PMID:26702928

  8. Amelogenin-Ameloblastin Spatial Interaction around Maturing Enamel Rods.

    Science.gov (United States)

    Mazumder, P; Prajapati, S; Bapat, R; Moradian-Oldak, J

    2016-08-01

    Amelogenin and ameloblastin are 2 extracellular matrix proteins that are essential for the proper development of enamel. We recently reported that amelogenin and ameloblastin colocalized during the secretory stage of enamel formation when nucleation of enamel crystallites occurs. Direct interactions between the 2 proteins have been also demonstrated in our in vitro studies. Here, we explore interactions between their fragments during enamel maturation. We applied in vivo immunofluorescence imaging, quantitative co-localization analysis, and a new FRET (fluorescence resonance energy transfer) technique to demonstrate ameloblastin and amelogenin interaction in the maturing mouse enamel. Using immunochemical analysis of protein samples extracted from 8-d-old (P8) first molars from mice as a model for maturation-stage enamel, we identified the ~17-kDa ameloblastin (Ambn-N) and the TRAP (tyrosine-rich amelogenin peptide) fragments. We used Ambn-N18 and Ambn-M300 antibodies raised against the N-terminal and C-terminal segments of ameloblastin, as well as Amel-FL and Amel-C19 antibodies against full-length recombinant mouse amelogenin (rM179) and C-terminal amelogenin, respectively. In transverse sections, co-localization images of N-terminal fragments of amelogenin and ameloblastin around the prism boundary revealed the "fish net" pattern of the enamel matrix. Using in vivo FRET microscopy, we further demonstrated spatial interactions between amelogenin and ameloblastin N-terminal fragments. In the maturing mouse enamel, the association of these residual protein fragments created a discontinuity between enamel rods, which we suggest is important for support and maintenance of enamel rods and eventual contribution to unique enamel mechanical properties. We present data that support cooperative functions of enamel matrix proteins in mediating the structural hierarchy of enamel and that contribute to our efforts to design and develop enamel biomimetic material. PMID

  9. Amelogenin signal peptide mutation: Correlation between mutations in the amelogenin gene (AMGX) and manifestations of X-linked amelogenesis imperfecta

    Energy Technology Data Exchange (ETDEWEB)

    Lagerstroem-Fermer, M.; Nilsson, M.; Pettersson, U. [Univ. of Uppsala (Sweden)] [and others

    1995-03-01

    Formation of tooth enamel is a poorly understood biological process. In this study the authors describe a 9-bp deletion in exon 2 of the amelogenin gene (AMGX) causing X-linked hypoplastic amelogenesis imperfecta, a disease characterized by defective enamel. The mutation results in the loss of 3 amino acids and exchange of 1 in the signal peptide of the amelogenin protein. This deletion in the signal peptide probably interferes with translocation of the amelogenin protein during synthesis, resulting in the thin enamel observed in affected members of the family. The authors compare this mutation to a previously reported mutation in the amelogenin gene that causes a different disease phenotype. The study illustrates that molecular analysis can help explain the various manifestations of a tooth disorder and thereby provide insights into the mechanisms of tooth enamel formation. 16 refs., 2 figs., 1 tab.

  10. Supramolecular Assembly of Biobased Graphene Oxide Quantum Dots Controls the Morphology of and Induces Mineralization on Poly(ε-caprolactone) Films.

    Science.gov (United States)

    Hassanzadeh, Salman; Adolfsson, Karin H; Wu, Duo; Hakkarainen, Minna

    2016-01-11

    Biobased 2D graphene oxide quantum dots (GOQDs) were synthesized from waste paper via carbon nanosphere intermediates and evaluated as property-enhancing additives for poly(ε-caprolactone) (PCL). The morphology of PCL films was controlled by supramolecular assembly of the small, 2D GOQDs in the polymer matrix. Phase behavior studies of PCL-GOQD in the solid state indicated concentration-dependent self-association of GOQD sheets, which was confirmed by SEM observations. Depending on the GOQD concentration, the formation of, e.g., spheres and stacked sheets was observed. GOQDs also induced mineralization on the surface of the films. A calcium phosphate (CaP) mineralization test revealed that the density of growing CaP crystals was controlled by the type of GOQD aggregates formed. Thus, utilization of the aggregation behavior of small GOQD sheets in polymeric matrices paves the way for tuning the morphology and properties of nanocomposites. PMID:26650535

  11. Supramolecular assembly of (Z)-ethyl 2-cyano-3-((4-fluorophenyl)amino) acrylate, crystal structure, Hirshfeld surface analysis and DFT studies

    Science.gov (United States)

    Matos, Catiúcia R. M. O.; Vitorino, Letícia S.; de Oliveira, Pedro H. R.; de Souza, Maria Cecília B. V.; Cunha, Anna C.; Boechat, Fernanda da C. S.; Resende, Jackson A. L. C.; Carneiro, José Walkimar de M.; Ronconi, Célia M.

    2016-09-01

    A mixture of the E and Z isomers of ethyl 2-cyano-3-((4-fluorophenyl)amino) acrylate was synthesized and characterized by elemental analysis, attenuated total reflectance-Fourier transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy. The structure of the Z isomer was determined by single crystal X-ray diffraction, which revealed a three-dimensional supramolecular network governed by Csbnd H⋯N, Csbnd H⋯O, and Csbnd H⋯F hydrogen bonds and π⋯π stacking interactions. The combination of these interactions plays an important role in stabilizing the self-assembly process and the molecular conformation. Hirshfeld surface analysis indicated the roles of the noncovalent interactions in the crystal packing, which were quantified by fingerprint plots and DFT calculations.

  12. Distribution of the amelogenin protein in developing, injured and carious human teeth

    Directory of Open Access Journals (Sweden)

    Thimios eMitsiadis

    2014-12-01

    Full Text Available Amelogenin is the major enamel matrix protein with key roles in amelogenesis. Although for many decades amelogenin was considered to be exclusively expressed by ameloblasts, more recent studies have shown that amelogenin is also expressed in other dental and no-dental cells. However, amelogenin expression in human tissues remains unclear. Here, we show that amelogenin protein is not only expressed during human embryonic development but also in pathological conditions such as carious lesions and injuries after dental cavity preparation. In developing embryonic teeth, amelogenin stage-specific expression is found in all dental epithelia cell populations but with different instensities. In the different layers of enamel matrix, waves of positive versus negative immunostaining for amelogenin are detected suggesting that the secretion of amelogenin protein is orchestreted by a biological clock. Amelogenin is also expressed transiently in differentiating odontoblasts during predentin formation, but was absent in mature functional odontoblasts. In intact adult teeth, amelogenin was not present in dental pulp, odontoblasts, and dentin. However, in injured and carious adult human teeth amelogenin is strongly re-expressed in newly differentiated odontoblasts and is distributed in the dentinal tubuli under the lesion site. In an in vitro culture system, amelogenin is expressed preferentially in human dental pulp cells that start differentiating into odontoblast-like cells and form mineralization nodules. These data suggest that amelogenin plays important roles not only during cytodifferentiation, but also during tooth repair processes in humans.

  13. Hierarchical self-assembly of switchable nucleolipid supramolecular gels based on environmentally-sensitive fluorescent nucleoside analogs

    Science.gov (United States)

    Nuthanakanti, Ashok; Srivatsan, Seergazhi G.

    2016-02-01

    Exquisite recognition and folding properties have rendered nucleic acids as useful supramolecular synthons for the construction of programmable architectures. Despite their proven applications in nanotechnology, scalability and fabrication of nucleic acid nanostructures still remain a challenge. Here, we describe a novel design strategy to construct new supramolecular nucleolipid synthons by using environmentally-sensitive fluorescent nucleoside analogs, based on 5-(benzofuran-2-yl)uracil and 5-(benzo[b]thiophen-2-yl)uracil cores, as the head group and fatty acids, attached to the ribose sugar, as the lipophilic group. These modified nucleoside-lipid hybrids formed organogels driven by hierarchical structures such as fibers, twisted ribbons, helical ribbons and nanotubes, which depended on the nature of fatty acid chain and nucleobase modification. NMR, single crystal X-ray and powder X-ray diffraction studies revealed the coordinated interplay of various non-covalent interactions invoked by modified nucleobase, sugar and fatty acid chains in setting up the pathway for the gelation process. Importantly, these nucleolipid gels retained or displayed aggregation-induced enhanced emission and their gelation behavior and photophysical properties could be reversibly switched by external stimuli such as temperature, ultrasound and chemicals. Furthermore, the switchable nature of nucleolipid gels to chemical stimuli enabled the selective two channel recognition of fluoride and Hg2+ ions through visual phase transition and fluorescence change. Fluorescent organogels exhibiting such a combination of useful features is rare, and hence, we expect that this innovative design of fluorescent nucleolipid supramolecular synthons could lead to the emergence of a new family of smart optical materials and probes.Exquisite recognition and folding properties have rendered nucleic acids as useful supramolecular synthons for the construction of programmable architectures. Despite their

  14. Nano-self-assemblies based on synthetic analogues of mycobacterial monomycoloyl glycerol and DDA: Supramolecular structure and adjuvant efficacy

    DEFF Research Database (Denmark)

    Martin-Bertelsen, Birte; Korsholm, Karen Smith; Christensen, Dennis;

    2016-01-01

    responses. In the present study, we investigated the supramolecular structure and in vivo adjuvant activity of dispersions based on binary mixtures of DDA and an array of synthetic MMG-1 analogues (MMG- 2/3/5/6) displaying longer (MMG-2) or shorter (MMG-3) alkyl chain lengths, or polar headgroup (MMG-5...... for DDA:MMG-3, depending on the DDA:MMG molar ratio. The studies also showed that ULVs were formed, regardless of the structural characteristics of the neat MMG analogues in excess buffer [lamellar (MMG-1/2/5) or inverse hexagonal (MMG-3/6) phases]. Immunization of mice with a chlamydia antigen surface...

  15. Design of bio-based supramolecular structures through self-assembly of α-lactalbumin and lysozyme

    OpenAIRE

    Monteiro, Adenilson A.; Monteiro, Marcia R.; Pereira, Ricardo N.; Diniz, Renata; Costa, Angélica R.; Malcata, F. Xavier; J. A. Teixeira; Teixeira, Álvaro V.; Oliveira, Eduardo B.; Coimbra, Jane S.; Vicente, A.A.; Ramos, Óscar L.

    2016-01-01

    Bovine α-lactalbumin (α-La) and lysozyme (Lys), two globular proteins with highly homologous tertiary structures and opposite isoelectric points, were used to produce bio-based supramolecular structures under various pH values (3, 7 and 11), temperatures (25, 50 and 75 °C) and times (15, 25 and 35 min) of heating. Isothermal titration calorimetry experiments showed protein interactions and demonstrated that structures were obtained from the mixture of α-La/Lys in molar ratio of 0.546. Structu...

  16. Applications of supramolecular chemistry

    CERN Document Server

    Schneider, Hans-Jörg

    2012-01-01

    ""The time is ripe for the present volume, which gathers thorough presentations of the numerous actually realized or potentially accessible applications of supramolecular chemistry by a number of the leading figures in the field. The variety of topics covered is witness to the diversity of the approaches and the areas of implementation…a broad and timely panorama of the field assembling an eminent roster of contributors.""-Jean-Marie Lehn, 1987 Noble Prize Winner in Chemistry

  17. Ionic supramolecular bonds preserve mechanical properties and enable synergetic performance at high humidity in water-borne, self-assembled nacre-mimetics

    Science.gov (United States)

    Das, Paramita; Walther, Andreas

    2013-09-01

    Although tremendous effort has been focused on enhancing the mechanical properties of nacre-mimetic materials, conservation of high stiffness and strength against hydration-induced decay of mechanical properties at high humidity remains a fundamental challenge in such water-borne high-performance materials. Herein, we demonstrate that ionic supramolecular bonds, introduced by infiltration of divalent Cu2+ ions, allow efficient stabilization of the mechanical properties of self-assembled water-borne nacre-mimetics based on sustainable sodium carboxymethylcellulose (Na+CMC) and natural sodium montmorillonite nanoclay (Na+MTM) against high humidity (95% RH). The mechanical properties in the highly hydrated state (Young's modulus up to 13.5 GPa and tensile strength up to 125 MPa) are in fact comparable to a range of non-crosslinked nacre-mimetic materials in the dry state. Moreover, the Cu2+-treated nacre-inspired materials display synergetic mechanical properties as found in a simultaneous improvement of stiffness, strength and toughness, as compared to the pristine material. Significant inelastic deformation takes place considering the highly reinforced state. This contrasts the typical behaviour of tight, covalent crosslinks and is suggested to originate from a sacrificial, dynamic breakage and rebinding of transient supramolecular ionic bonds. Considering easy access to a large range of ionic interactions and alteration of counter-ion charge via external stimuli, we foresee responsive and adaptive mechanical properties in highly reinforced and stiff bio-inspired bulk nanocomposites and in other bio-inspired materials, e.g. nanocellulose papers and peptide-based materials.Although tremendous effort has been focused on enhancing the mechanical properties of nacre-mimetic materials, conservation of high stiffness and strength against hydration-induced decay of mechanical properties at high humidity remains a fundamental challenge in such water-borne high

  18. Supramolecular architectures from the self-assembly of lanthanide ions with 6-hydroxypicolinic acid and 1,10-phenanthroline

    Science.gov (United States)

    Sun, Chang-Yan; Jin, Lin-Pei

    2005-05-01

    Three new lanthanide complexes, [La(HpicO) 3(phen)(H 2O)] n ( 1) and Ln 3(picO) 4(phen) 3(H 2O) 2·HpicO·0.5H 2O (Ln=Er ( 2), Yb ( 3)) were synthesized by the hydrothermal reactions and characterized by single crystal X-ray diffraction, elemental analysis and IR spectrum. In complex 1, each La(III) ion is 10-coordinated and HpicO - ligands link the metal ions into 1D zigzag chains. Complexes 2 and 3 are isomorphous, and there are three crystallographically independent Ln(III) ions in the asymmetric unit. The N-H⋯O and O-H⋯O hydrogen bonds and π-π stacking interactions in these complexes result in the formation of 3D supramolecular architectures.

  19. Applying low-molecular weight supramolecular gelators in an environmental setting - self-assembled gels as smart materials for pollutant removal.

    Science.gov (United States)

    Okesola, Babatunde O; Smith, David K

    2016-07-25

    This review explores supramolecular gels as materials for environmental remediation. These soft materials are formed by self-assembling low-molecular-weight building blocks, which can be programmed with molecular-scale information by simple organic synthesis. The resulting gels often have nanoscale 'solid-like' networks which are sample-spanning within a 'liquid-like' solvent phase. There is intimate contact between the solvent and the gel nanostructure, which has a very high effective surface area as a result of its dimensions. As such, these materials have the ability to bring a solid-like phase into contact with liquids in an environmental setting. Such materials can therefore remediate unwanted pollutants from the environment including: immobilisation of oil spills, removal of dyes, extraction of heavy metals or toxic anions, and the detection or removal of chemical weapons. Controlling the interactions between the gel nanofibres and pollutants can lead to selective uptake and extraction. Furthermore, if suitably designed, such materials can be recyclable and environmentally benign, while the responsive and tunable nature of the self-assembled network offers significant advantages over other materials solutions to problems caused by pollution in an environmental setting. PMID:27241027

  20. The Self-Assembly of Nano-Objects Code: Applications to supramolecular organic monolayers adsorbed on metal surfaces

    OpenAIRE

    Roussel, Thomas; Vega, Lourdes F.

    2012-01-01

    The Self-Assembly of Nano-Objects (SANO) code we implemented demonstrates the ability to predict the molecular self-assembly of different structural motifs by tuning the molecular building blocks as well as the metallic substrate. It consists in a two-dimensional Grand Canonical Monte-Carlo (GCMC) approach developed to perform atomistic simulations of thousands of large organic molecules self-assembling on metal surfaces. Computing adsorption isotherms at room temperature and spanning over th...

  1. Tracking endogenous amelogenin and ameloblastin in vivo.

    Directory of Open Access Journals (Sweden)

    Jaime Jacques

    Full Text Available Research on enamel matrix proteins (EMPs is centered on understanding their role in enamel biomineralization and their bioactivity for tissue engineering. While therapeutic application of EMPs has been widely documented, their expression and biological function in non-enamel tissues is unclear. Our first aim was to screen for amelogenin (AMELX and ameloblastin (AMBN gene expression in mandibular bones and soft tissues isolated from adult mice (15 weeks old. Using RT-PCR, we showed mRNA expression of AMELX and AMBN in mandibular alveolar and basal bones and, at low levels, in several soft tissues; eyes and ovaries were RNA-positive for AMELX and eyes, tongues and testicles for AMBN. Moreover, in mandibular tissues AMELX and AMBN mRNA levels varied according to two parameters: 1 ontogenic stage (decreasing with age, and 2 tissue-type (e.g. higher level in dental epithelial cells and alveolar bone when compared to basal bone and dental mesenchymal cells in 1 week old mice. In situ hybridization and immunohistodetection were performed in mandibular tissues using AMELX KO mice as controls. We identified AMELX-producing (RNA-positive cells lining the adjacent alveolar bone and AMBN and AMELX proteins in the microenvironment surrounding EMPs-producing cells. Western blotting of proteins extracted by non-dissociative means revealed that AMELX and AMBN are not exclusive to mineralized matrix; they are present to some degree in a solubilized state in mandibular bone and presumably have some capacity to diffuse. Our data support the notion that AMELX and AMBN may function as growth factor-like molecules solubilized in the aqueous microenvironment. In jaws, they might play some role in bone physiology through autocrine/paracrine pathways, particularly during development and stress-induced remodeling.

  2. Surfactant assisted self-assembly of zinc 5,10-bis (4-pyridyl)-15,20-bis (4-octadecyloxyphenyl) porphyrin into supramolecular nanoarchitectures

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, Renu; Chauhan, S.M.S., E-mail: smschauhan@chemistry.du.ac.in

    2014-10-01

    The surfactant assisted self-assembly (SAS) method has been used in the formation of nanocubes, nanorods and microrods from zinc 5,10-bis (4-pyridyl)-15,20-bis (4-octadecyloxyphenyl) porphyrin. By the dropwise addition of chloroform solution of the zinc porphyrin into an aqueous solution of cetyltrimethylammonium bromide (CTAB), cuboidal nanostructures are formed at the initial stage. The nanocubes are transformed into nanorods and microrods by aging under ambient conditions. The longer nanorods with well defined edges have been formed with lower concentration of porphyrin solution whereas the shorter nanorods have been formed with higher concentration of zinc porphyrin. The synergistic effect of hydrophobic interactions by the long alkyl chains substituted on the peripheral phenyl rings of porphyrin and axial coordination of pyridyl nitrogen atoms with central zinc is mainly responsible for the formation of different nanostructures. The nanostructures were characterized by UV–visible spectra, fluorescence spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), IR spectroscopy and X-ray diffraction (XRD) pattern. - Graphical abstract: Supramolecular nanocubes, nanorods and microrods have been controllably fabricated by a simple surfactant-assisted solution route using unsymmetrical porphyrin bearing self assembly motifs. - Highlights: • Nanoaggregates from unsymmetrical porphyrin using surfactant were fabricated. • Zn–N axial interaction and hydrophobic interaction play a major role in aggregation. • Self-assembly can be controlled via porphyrin concentration and aging time. • A possible explanation for the fabrication of nanoaggregates has been proposed. • Highly ordered J type of aggregation takes place.

  3. Supramolecular biomaterials

    Science.gov (United States)

    Webber, Matthew J.; Appel, Eric A.; Meijer, E. W.; Langer, Robert

    2016-01-01

    Polymers, ceramics and metals have historically dominated the application of materials in medicine. Yet rationally designed materials that exploit specific, directional, tunable and reversible non-covalent interactions offer unprecedented advantages: they enable modular and generalizable platforms with tunable mechanical, chemical and biological properties. Indeed, the reversible nature of supramolecular interactions gives rise to biomaterials that can sense and respond to physiological cues, or that mimic the structural and functional aspects of biological signalling. In this Review, we discuss the properties of several supramolecular biomaterials, as well as their applications in drug delivery, tissue engineering, regenerative medicine and immunology. We envision that supramolecular biomaterials will contribute to the development of new therapies that combine highly functional materials with unmatched patient- and application-specific tailoring of both material and biological properties.

  4. Identification of a novel splicing form of amelogenin gene in a reptile, Ctenosaura similis.

    Directory of Open Access Journals (Sweden)

    Xinping Wang

    Full Text Available Amelogenin, the major enamel matrix protein in tooth development, has been demonstrated to play a significant role in tooth enamel formation. Previous studies have identified the alternative splicing of amelogenin in many mammalian vertebrates as one mechanism for amelogenin heterogeneous expression in teeth. While amelogenin and its splicing forms in mammalian vertebrates have been cloned and sequenced, the amelogenin gene, especially its splicing forms in non-mammalian species, remains largely unknown. To better understand the mechanism underlying amelogenin evolution, we previously cloned and characterized an amelogenin gene sequence from a squamate, the green iguana. In this study, we employed RT-PCR to amplify the amelogenin gene from the black spiny-tailed iguana Ctenosaura similis teeth, and discovered a novel splicing form of the amelogenin gene. The transcript of the newly identified iguana amelogenin gene (named C. Similis-T2L is 873 nucleotides long encoding an expected polypeptide of 206 amino acids. The C. Similis-T2L contains a unique exon denominated exon X, which is located between exon 5 and exon 6. The C. Similis-T2L contains 7 exons including exon 1, 2, 3, 5, X, 6, and 7. Analysis of the secondary and tertiary structures of T2L amelogenin protein demonstrated that exon X has a dramatic effect on the amelogenin structures. This is the first report to provide definitive evidence for the amelogenin alternative splicing in non-mammalian vertebrates, revealing a unique exon X and the splicing form of the amelogenin gene transcript in Ctenosaura similis.

  5. Influences of hydrophilic and hydrophobic substituents on the organization of supramolecular assemblies of porphyrin derivatives formed at the air/water interface

    International Nuclear Information System (INIS)

    Monolayers and Langmuir-Blodgett (LB) films of several kinds of porphyrin derivatives that have different substituted alkyl chain length, chain numbers and central metals were studied by π-A isotherms, UV-Vis, polarized UV-Vis and fluorescence spectroscopy and low angle X-ray diffractometry (LAXD). The orientation angles of porphyrin rings and alkyl chains were derived from the polarized UV-Vis spectra and LAXD patterns of the monolayers or LB films, respectively. The rings of the freebase porphyrins with different alkyl chain length or number have similar orientation angles in the films due to the same hydrophilic groups on the rings, and those of metal porphyrins have different orientation angles from each other. The orientation of the alkyl chains is related to the special positions of the chains on the rings and the orientation of the rings. The influences of the hydrophilicity of the hydrophilic groups and the alkyl chain number and length on the organization of the supramolecular assemblies of the porphyrin derivatives were discussed

  6. Metal-organic and supramolecular networks driven by 5-chloronicotinic acid: Hydrothermal self-assembly synthesis, structural diversity, luminescent and magnetic properties

    Science.gov (United States)

    Gao, Zhu-Qing; Li, Hong-Jin; Gu, Jin-Zhong; Zhang, Qing-Hua; Kirillov, Alexander M.

    2016-09-01

    Four new crystalline solids, namely [Co2(μ2-5-Clnic)2(μ3-5-Clnic)2(μ2-H2O)]n (1), [Co(5-Clnic)2(H2O)4]·2(5-ClnicH) (2), [Pb(μ2-5-Clnic)2(phen)]n (3), and [Cd(5-Clnic)2(phen)2]·3H2O (4) were generated by hydrothermal self-assembly methods from the corresponding metal(II) chlorides, 5-chloronicotinic acid (5-ClnicH) as a principal building block, and 1,10-phenanthroline (phen) as an ancillary ligand (optional). All the products 1-4 were characterized by IR spectroscopy, elemental analysis, thermogravimetric (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Their structures range from an intricate 3D metal-organic network 1 with the 3,6T7 topology to a ladder-like 1D coordination polymer 3 with the 2C1 topology, whereas compounds 2 and 4 are the discrete 0D monomers. The structures of 2 and 4 are further extended (0D→2D or 0D→3D) by hydrogen bonds, generating supramolecular networks with the 3,8L18 and ins topologies, respectively. Synthetic aspects, structural features, thermal stability, magnetic (for 1) and luminescent (for 3 and 4) properties were also investigated and discussed.

  7. Supramolecular assembly and nanostructures of a series of luminol derivatives with aromatic/alkyl substituted groups in Langmuir-Blodgett films.

    Science.gov (United States)

    Jiao, Tifeng; Xing, Yuanyuan; Zhang, Qingrui; Zhang, Li; Liu, Minghua; Zhou, Jingxin; Gao, Faming

    2014-06-01

    A series of functional luminol derivatives with aromatic and alkyl substituted groups has been designed and synthesized from the reaction of the corresponding chloride precursors with luminol. These compounds can be spread on water surface to form stable Langmuir films at the air-water interface. It has been found that UV and IR spectra confirmed the characteristic aromatic segment, imide group, and aromatic/alkyl substituted groups. In addition, for the interfacial assembly process of compounds with alkyl substituted groups, there are obvious spectral changes for the alkyl chains. AFM results indicated that various different aggregated domains may be fabricated in the transferred LB films. For all cases, the substituted groups in molecular structures have an important effect in regulating the aggregation mode and spectral changes in organized molecular films. The present results showed that the modified luminol derivatives may have potential application in functional material fields such as ECL sensor, which may give some insight to study the relationship between the molecular structures and supramolecular aggregation of amphiphiles in organized molecular films.

  8. Supramolecular Assembly of Molecular Rare-Earth-3,5-Dichlorobenzoic Acid-2,2':6',2″-Terpyridine Materials: Structural Systematics, Luminescence Properties, and Magnetic Behavior.

    Science.gov (United States)

    Carter, Korey P; Thomas, Kara E; Pope, Simon J A; Holmberg, Rebecca J; Butcher, Ray J; Murugesu, Muralee; Cahill, Christopher L

    2016-07-18

    The syntheses and crystal structures of 16 new rare-earth (RE = La(3+)-Y(3+))-3,5-dichlorobenzoic acid-terpyridine molecular materials characterized via single-crystal and powder X-ray diffraction are reported. These 16 complexes consist of four unique structure types ranging from molecular dimers (La(3+) and Ce(3+)) to tetramers (Pr(3+)-Y(3+)) as one moves across the RE(3+) series. This structural evolution is accompanied by subsequent changes in modes of supramolecular assembly (halogen bonding, halogen-π, halogen-halogen, and π-π interactions). Solid-state visible and near-infrared lifetime measurements were performed on complexes 6 (Sm(3+)), 7 (Eu(3+)), 9 (Tb(3+)), 10 (Dy(3+)), 11 (Ho(3+)), 12 (Er(3+)), and 14 (Yb(3+)), and characteristic emission was observed for all complexes except 11. Lifetime data for 11, 12, and 14 suggest sensitization by the terpy antenna does occur in near-infrared systems, although not as efficiently as in the visible region. Additionally, direct current magnetic susceptibility measurements were taken for complexes 10 (Dy(3+)) and 12 (Er(3+)) and showed dominant ferromagnetic behavior. PMID:27347607

  9. Enzyme-catalyzed preparation of supramolecular structured hydrogel of polypseudorotaxanes derived from the self-assembly of α-CDs with 3-arm p-hydroxyphenylpropionate terminated PEG

    Institute of Scientific and Technical Information of China (English)

    XIE Zhiguo; HOU Dandan; YE Lin; ZHANG Aiying; FENG Zengguo

    2007-01-01

    A kind of novel 3-D cross-1inked supramolecular structured hydrogels has been fabricated via enzymatic oxidative coupling of polypseudorotaxanes (PPRs) derived from the self-assembly of α-cyclodextrins (α-CDs) with 3-arm p-hydroxyphenylpropionate terminated PEG (3-HPPP) as a macromer by using horseradish peroxidase (HRP)/H2O2 catalytic system.The enzymatic cross-1inking of the macromer or PPRs made with a smaller amount of α-CDs was found to be much faster than that by ordinary chemical pathways,showing the promise to be used as the surgical adhesive and sealant which are needed to rapidly function in vivo.The gelation time was highly extended and the gel content was considerably decreased by increasing the α-CDs to macromer feeding molar ratio.Thereby these hydrogels exhibited a decreasing trend in dynamical mechanical properties with increasing the amount of α-CDs in regard to the blank hydrogel made without α-CD addition.

  10. Supramolecular perspectives in colloid science

    NARCIS (Netherlands)

    Cohen Stuart, M.A.

    2008-01-01

    Supramolecular chemistry puts emphasis on molecular assemblies held together by non-covalent bonds. As such, it is very close in spirit to colloid science which also focuses on objects which are small, but beyond the molecular scale, and for which other forces than covalent bonds are crucial. We dis

  11. Supramolecular assemblies based on complexes of nonionic amphiphilic cyclodextrins and a meso-tetra(4-sulfonatophenyl)porphine tributyltin(IV) derivative: potential nanotherapeutics against melanoma.

    Science.gov (United States)

    Mazzaglia, Antonino; Bondì, Maria Luisa; Scala, Angela; Zito, Francesca; Barbieri, Giovanna; Crea, Francesco; Vianelli, Giuseppina; Mineo, Placido; Fiore, Tiziana; Pellerito, Claudia; Pellerito, Lorenzo; Costa, Maria Assunta

    2013-11-11

    Amphiphilic cyclodextrin (ACyD) provides water-soluble and adaptable nanovectors by modulating the balance between the hydrophobic and hydrophilic chains at both CyD sides. This work aimed to design nanoassemblies based on nonionic and hydrophilic ACyD (SC6OH) for the delivery of a poor-water-soluble organotin(IV)-porphyrin derivative [(Bu3Sn)4TPPS] to melanoma cancer cells. To characterize the porphyrin derivatives under simulated physiological conditions, a speciation was performed using complementary techniques. In aqueous solution (≤ 20 μM), (Bu3Sn)4TPPS primarily exists as a monomer (2 in Figure 1), as suggested by the low static anisotropy (ρ ≈ 0.02) with a negligible formation of porphyrin supramolecular aggregates. MALDI-TOF spectra indicate the presence of moieties (i.e., [(Bu3Sn)3TPPS](-)) that are derivatives of the monomeric species. Spectrofluorimetry coupled with potentiometric measurements primarily assesses the presence of the hydrolytic [(Bu3Sn)4TPPS (OH)4](4-) species under physiological conditions. Nanoassemblies of (Bu3Sn)4TPPS/SC6OH were prepared by dispersion of organic films in PBS at pH 7.4 and were investigated using a combination of spectroscopic and morphological techniques. The UV-vis and emission fluorescence spectra of the (Bu3Sn)4TPPS/SC6OH reveal shifts in the peculiar bands of the organotin(IV)-porphyrin derivative due to its interaction with the ACyD supramolecular assemblies in aqueous solution. The mean size was within the range of 100-120 nm. The ξ-potential was negative (-16 mV) for the (Bu3Sn)4TPPS/SC6OH nanoassemblies, with an entrapment efficiency of approximately 67%. The intracellular delivery, cytotoxicity, nuclear morphology and cell growth kinetics were evaluated via fluorescence microscopy on A375 human melanoma cells. The delivery of (Bu3Sn)4TPPS by ACyD with respect to free (Bu3Sn)4TPPS increases the internalization efficiency and cytotoxicity to induce apoptotic cell death and, at lower concentrations

  12. Supramolecular synthons on surfaces : Controlling dimensionality and periodicity of tetraarylporphyrin assemblies by the interplay of cyano and alkoxy substituents

    NARCIS (Netherlands)

    Wintjes, Nikolai; Hornung, Jens; Lobo-Checa, Jorge; Voigt, Tobias; Samuely, Tomáš; Thilgen, Carlo; Stöhr, Meike; Diederich, François; Jung, Thomas A.

    2008-01-01

    The self-assembly of three porphyrin derivatives was studied in detail on a Cu(111) substrate by means of scanning tunneling microscopy (STM). All derivatives have two 4-cyanophenyl substituents in diagonally opposed meso-positions of the porphyrin core. but differ in the nature of the other two mes

  13. Self-Assembled Ionophores from Isoguanosine: Diffusion NMR Spectroscopy Clarifies Cation's and Anion's Influence on Supramolecular Structure

    NARCIS (Netherlands)

    Evan-Salem, Tamar; Frish, Limor; Leeuwen, van Fijs W.B.; Reinhoudt, David N.; Verboom, Willem; Kaucher, Mark S.; Davis, Jeffery T.; Cohen, Yoram

    2007-01-01

    Cation-templated self-assembly of the lipophilic isoguanosine (isoG 1) with different monovalent cations (M+=Li+, Na+, K+, NH4+, and Cs+) was studied in solvents of different polarity by using diffusion NMR spectroscopy. Previous studies that did not use diffusion NMR techniques concluded that isoG

  14. Unraveling the nanostructure of supramolecular assemblies of hydrogen-bonded rosettes on graphite: An atomic force microscopy study

    Science.gov (United States)

    Schönherr, Holger; Paraschiv, Vasile; Zapotoczny, Szczepan; Crego-Calama, Mercedes; Timmerman, Peter; Frank, Curtis W.; Vancso, G. Julius; Reinhoudt, David N.

    2002-01-01

    The self-organization of multicomponent tetrarosette assemblies into ordered nanostructures on graphite surfaces has been studied by atomic force microscopy (AFM). Real-space information on the level of individual molecules allowed us to analyze the underlying structure in unprecedented detail. In highly ordered nanorod domains, tetrarosettes 13⋅(DEB)12 arrange in the form of parallel rows with a spacing of 4.6 ± 0.1 nm. High resolution AFM revealed the internal packing of the tetrarosette assemblies in these rows, which can be described by an oblique lattice with a = 2.5 ± 0.3 nm, b = 5.0 ± 0.1 nm, and γ = 122 ± 3°. The results, together with recent improvements in synthetic approaches, contribute to the development of a general strategy to develop H-bonding-based nanostructures with molecular precision. PMID:11929980

  15. Supramolecular assembly with ionic, redox-responsive poly(ferrocenylsilanes) : engineering of interfaces and molecular release applications

    OpenAIRE

    Ma, Yujie

    2008-01-01

    This thesis describes the synthesis and electrostatic assembly of organometallic poly(ferrocenylsilane) (PFS) strong polyelectrolytes. The distinctive structural features of poly(ferrocenylsilanes) come from the silicon and iron atoms in the main chain. The presence of redox-active ferrocene units in the polymer backbone provides unique redox-responsive properties to PFS. The charged nature and redox-responsiveness of these organometallic polyelectrolytes makes them particularly useful in the...

  16. Sequence variation of the amelogenin gene on the Y-chromosome / by Irma Ferreira

    OpenAIRE

    Ferreira, Irma

    2010-01-01

    The accurate determination of gender of biological samples has valuable applications in medical and forensic investigations. Gender determination based on length variations in the X-Y homologous amelogenin gene, is part of most commercial multiplex DNA profiling kits. The first report of a failure of the amelogenin sex test was in 1998 when two normal males were typed as female. Subsequently, several amelogenin Y (AMELY) negative males have been reported. This study repre...

  17. Self-assembled supramolecular hydrogel based on PCL-PEG-PCL triblock copolymer and γ-cyclodextrin inclusion complex for sustained delivery of dexamethasone.

    Science.gov (United States)

    Khodaverdi, Elham; Gharechahi, Marzieh; Alibolandi, Mona; Tekie, Farnaz Sadat Mirzazadeh; Khashyarmanesh, Bibi Zahra; Hadizadeh, Farzin

    2016-01-01

    In this study, thermosensitive, water-soluble, and biodegradable triblock copolymer PCL600-PEG6000-PCL600 was used to form supramolecular hydrogel (SMGel) by inclusion complexation with γ-cyclodextrin (γ-CD). The prepared SMGel was investigated as a carrier for sustained release of dexamethasone. The triblock copolymer PCL-PEG-PCL [where PCL = polycaprolactone, PEG = poly(ethylene glycol)] was synthesized by the ring-opening polymerization method using microwave irradiation. The polymerization reaction and the copolymer structures were evaluated by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). SMGel was prepared in aqueous solution by blending an aqueous γ-CD solution with aqueous solution of PCL-PEG-PCL triblock copolymer at room temperature. The sol-to-gel transition time was measured at various concentrations of copolymer and γ-CD. As-prepared SMGel was used to prepare a sustained, controllable drug delivery system of dexamethasone sodium phosphate. The SMGel was also characterized in terms of rheological, morphological, and structural properties. Results obtained from proton nuclear magnetic resonance ( (1)H-NMR) and GPC demonstrated that microwave irradiation is a simple and reliable method for synthesis of PEG-PCL copolymer. The SMGel with excellent syringability was prepared by mixing of 20% wt γ-CD and 10% wt of copolymer within 4 s. The SMGel containing 10% wt copolymer, 20% wt γ-CD, and 0.5% or 0.1% wt dexamethasone released approximately 100% and 45% of drug over up to 23 days, respectively. It could be concluded that SMGel based on self-assembly of inclusion complexes between PCL-PEG-PCL copolymer and γ-CD could be used as a basis for injectable drug delivery systems that provide sustained and controlled release of macromolecular drugs such as dexamethasone. PMID:27051627

  18. Expression of amelogenin and effects of cyclosporin A in developing hair follicles in rats.

    Science.gov (United States)

    Yoo, Hong-Il; Lee, Gye-Hyeok; Lee, Su-Young; Kang, Jee-Hae; Moon, Jung-Sun; Kim, Min-Seok; Kim, Sun-Hun

    2016-01-01

    Amelogenin, an enamel matrix protein has been considered to be exclusively expressed by ameloblasts during odontogenesis. However, burgeoning evidence indicates that amelogenin is also expressed in non-mineralizing tissues. Under the hypothesis that amelogenin may be a functional molecule in developing hair follicles which share developmental features with odontogenesis, this study for the first time elucidated the presence and functional changes of amelogenin and its receptors during rat hair follicle development. Amelogenin was specifically localized in the outer epithelial root sheath of hair follicles. Its expression appeared in the deeper portion of hair follicles, i.e. the bulbar and suprabulbar regions rather than the superficial region. Lamp-1, an amelogenin receptor, was localized in either follicular cells or outer epithelial sheath cells, reflecting functional changes during development. The expression of amelogenin splicing variants increased in a time-dependent manner during postnatal development of hair follicles. Amelogenin expression was increased by treatment with cyclosporin A, which is an inducer of anagen in the hair follicle, whereas the level of Lamp-1 and -2 was decreased by cyclosporin A treatment. These results suggest that amelogenin may be a functional molecule involved in the development of the hair follicle rather than an inert hair shaft matrix protein. PMID:26426935

  19. Shuttle-like supramolecular nanostructures formed by self-assembly of a porphyrin via an oil/water system

    Directory of Open Access Journals (Sweden)

    Guo Peipei

    2011-01-01

    Full Text Available Abstract In this paper, in terms of the concentration of an aqueous solution of a surfactant, we investigate the self-assembly behavior of a porphyrin, 5, 10, 15, 20-tetra(4-pyridyl-21H, 23H-porphine [H2TPyP], by using an oil/water system as the medium. We find that when a chloroform solution of H2TPyP is dropwise added into an aqueous solution of cetyltrimethylammonium bromide [CTAB] with a lower concentration, a large amount of irregular nanoarchitectures, together with a small amount of well-defined shuttle-like nanostructures, hollow nanospheres, and nanotubes, could be produced. While a moderate amount of shuttle-like nanostructures accompanied by a few irregular nanoarchitectures, solid nanospheres, and nanorods are produced when a CTAB aqueous solution in moderate concentration is employed, in contrast, a great quantity of shuttle-like nanostructures together with a negligible amount of solid nanospheres, nanofibers, and irregular nanostructures are manufactured when a high-concentration CTAB aqueous solution is involved. An explanation on the basis of the molecular geometry of H2TPyP and in terms of the intermolecular π-π interactions between H2TPyP units, and hydrophobic interactions between CTAB and H2TPyP has been proposed. The investigation gives deep insights into the self-assembly behavior of porphyrins in an oil/water system and provides important clues concerning the design of appropriate porphyrins when related subjects are addressed. Our investigation suggests that an oil/aqueous system might be an efficient medium for producing unique organic-based nanostructures.

  20. Supramolecular approaches for drug development.

    Science.gov (United States)

    Kawakami, K; Ebara, M; Izawa, H; Sanchez-Ballester, N M; Hill, J P; Ariga, K

    2012-01-01

    Various supramolecular systems can be used as drug carriers to alter physicochemical and pharmacokinetic characteristics of drugs. Representative supramolecular systems that can be used for this purpose include surfactant/polymer micelles, (micro)emulsions, liposomes, layer-by-layer assemblies, and various molecular conjugates. Notably, liposomes are established supramolecular drug carriers, which have already been marketed in formulations including AmBisome(®) (for treatment of fungal infection), Doxil(®) (for Kaposi's sarcoma), and Visudyne(®) (for age-related macular degeneration and choroidal neovascularization). Microemulsions have been used oral drug delivery of poorly soluble drugs due to improvements in bioavailability and predictable of absorption behavior. Neoral(®), an immunosuppressant used after transplant operations, is one of the most famous microemulsion-based drugs. Polymer micelles are being increasingly investigated as novel drug carriers and some formulations have already been tested in clinical trials. Supramolecular systems can be functionalized by designing the constituent molecules to achieve efficient delivery of drugs to desired sites in the body. In this review, representative supramolecular drug delivery systems, that may improve usability of candidate drugs or add value to existing drugs, are introduced. PMID:22455591

  1. Self-assembly mechanism of 1,3:2,4-di(3,4-dichlorobenzylidene)-D-sorbitol and control of the supramolecular chirality.

    Science.gov (United States)

    Li, Jingjing; Fan, Kaiqi; Guan, Xidong; Yu, Yingzhe; Song, Jian

    2014-11-11

    Dibenzylidene-D-sorbitol (DBS) and its derivatives are known to form gels in organic solvents; however, the mechanism of the gel formation has been a subject of much debate. The present work is undertaken to elucidate the organization mechanism of a DBS derivative, 1,3:2,4-di(3,4-dichlorobenzylidene)-D-sorbitol (DCDBS), by taking into account the solvent effects and comparing the experiment data with theoretical calculation. These molecules form smooth nonhelical fibers with a rest circular dichroism (CD) signal in polar solvents, in contrast to rope-liked left-helical fibers with a strong negative CD signal observed in nonpolar solvents. The molecular complexes thus formed were characterized by means of Fourier transform infrared spectra, ultraviolet-visible spectra, X-ray diffraction patterns, static contact angles, and theoretical calculations. It was proposed that the interactions between the gelator and the solvents could subtly change the stacking of the molecules and hence their self-assembled nanostructures. In nonpolar solvents, the gelator molecules appear as a distorted T-shaped structure with the 6-OH forming intermolecular hydrogen bonds with the acetal oxygens of adjacent gelator molecule. In addition, because of differential stacking interactions on both sides of the 10-member ring skeleton of the gelator, the oligomers may assemble in a helix fashion to minimize the energy, leading to helical fibers. In polar solvents, however, the gelator molecules show a rigid planelike structure and thus stack on top of each other because of strong parallel-displaced π interactions. The balanced driving force on both sides of the 10-member ring skeleton made it difficult for the dimers to bend, thus resulting in nonhelical nanostructure. As expected from the mechanisms proposed here, twisted ribbon fibers with a medium strength CD signal were obtained when solvents of different polarities were mixed. Thus, solvent effects revealed in this work represent an

  2. Supramolecular self-assembly of graphene oxide and metal nanoparticles into stacked multilayers by means of a multitasking protein ring

    Science.gov (United States)

    Ardini, Matteo; Golia, Giordana; Passaretti, Paolo; Cimini, Annamaria; Pitari, Giuseppina; Giansanti, Francesco; Leandro, Luana Di; Ottaviano, Luca; Perrozzi, Francesco; Santucci, Sandro; Morandi, Vittorio; Ortolani, Luca; Christian, Meganne; Treossi, Emanuele; Palermo, Vincenzo; Angelucci, Francesco; Ippoliti, Rodolfo

    2016-03-01

    Graphene oxide (GO) is rapidly emerging worldwide as a breakthrough precursor material for next-generation devices. However, this requires the transition of its two-dimensional layered structure into more accessible three-dimensional (3D) arrays. Peroxiredoxins (Prx) are a family of multitasking redox enzymes, self-assembling into ring-like architectures. Taking advantage of both their symmetric structure and function, 3D reduced GO-based composites are hereby built up. Results reveal that the ``double-faced'' Prx rings can adhere flat on single GO layers and partially reduce them by their sulfur-containing amino acids, driving their stacking into 3D multi-layer reduced GO-Prx composites. This process occurs in aqueous solution at a very low GO concentration, i.e. 0.2 mg ml-1. Further, protein engineering allows the Prx ring to be enriched with metal binding sites inside its lumen. This feature is exploited to both capture presynthesized gold nanoparticles and grow in situ palladium nanoparticles paving the way to straightforward and ``green'' routes to 3D reduced GO-metal composite materials.Graphene oxide (GO) is rapidly emerging worldwide as a breakthrough precursor material for next-generation devices. However, this requires the transition of its two-dimensional layered structure into more accessible three-dimensional (3D) arrays. Peroxiredoxins (Prx) are a family of multitasking redox enzymes, self-assembling into ring-like architectures. Taking advantage of both their symmetric structure and function, 3D reduced GO-based composites are hereby built up. Results reveal that the ``double-faced'' Prx rings can adhere flat on single GO layers and partially reduce them by their sulfur-containing amino acids, driving their stacking into 3D multi-layer reduced GO-Prx composites. This process occurs in aqueous solution at a very low GO concentration, i.e. 0.2 mg ml-1. Further, protein engineering allows the Prx ring to be enriched with metal binding sites inside its

  3. Multivalent supramolecular dendrimer-based drugs.

    Science.gov (United States)

    Galeazzi, Simone; Hermans, Thomas M; Paolino, Marco; Anzini, Maurizio; Mennuni, Laura; Giordani, Antonio; Caselli, Gianfranco; Makovec, Francesco; Meijer, E W; Vomero, Salvatore; Cappelli, Andrea

    2010-01-11

    Supramolecular complexes consisting of a hydrophobic dendrimer host [DAB-dendr-(NHCONH-Ad)(64)] as well as solubilizing and bioactive guest molecules have been synthesized using a noncovalent approach. The guest-host supramolecular assembly is first preassembled in chloroform and transferred via the neat phase to aqueous solution. The bioactive guest molecules can bind to a natural (serotonin 5-HT(3)) receptor with nanomolar affinity as well as to the synthetic dendrimer receptor in aqueous solution, going toward a dynamic multivalent supramolecular construct capable of adapting itself to a multimeric receptor motif.

  4. Supramolecular assembly based on a heteropolyanion: Synthesis and crystal structure of Na3(H2O)6[Al(OH)6Mo6O18]$\\cdot$2H2O

    Indian Academy of Sciences (India)

    Vaddypally Shivaiah; Samar K Das

    2005-05-01

    Synthesis and structural characterization of a polyoxometalate compound Na3(H2O)6 [Al(OH)6Mo6O18]$\\cdot$2H2O (1) have been described. Compound 1 exhibits three-dimensional network structure in the solid state, which is assembled by Anderson-type heteropolyanions, [Al(OH)6Mo6O18]$_n^{3n-}$, as building blocks sharing sodium cations. 1 possesses ``sinuous" channels occupied by supramolecular water dimers as guests. Anderson anions, sodium-coordinated water and crystal water are additionally involved in an intricate hydrogen-bonding network in the crystal of 1.

  5. Assembly of polymeric silver(I) complexes of isomeric phenylenediethynides with the supramolecular synthons Agn subset C2-R-C2 superset Agn (R = p-, m-, o-C6H4; n = 4, 5).

    Science.gov (United States)

    Zhao, Liang; Mak, Thomas C W

    2005-11-01

    New Agn subset C2-R-C2 supersetAgn (R = p-, m-, o-C6H4; n = 4, 5) supramolecular synthons have been explored in the coordination network assembly of silver(I) complexes of the isomeric phenylenediethynides. An unprecedented mu5-eta1-coordination mode for the ethynide moiety and a mixed mu4,mu5-coordination mode for the o-phenylenediethynide group are observed, providing a rationale for the abundant occurrence of C2@Agn (n

  6. Hydrogen Bonded Supramolecular Polymers in Both Apolar and Aqueous Media: Self-Assembly and Reversible Conversion of Vesicles and Gels%Hydrogen Bonded Supramolecular Polymers in Both Apolar and Aqueous Media: Self-Assembly and Reversible Conversion of Vesicles and Gels

    Institute of Scientific and Technical Information of China (English)

    杜平; 孔军; 王贵涛; 赵新; 李光玉; 蒋锡夔; 黎占亭

    2011-01-01

    In a preliminary letter (Tetrahedron Lett. 2010, 51, 188), we reported two new hydrazide-based quadruple hydrogen-bonding motifs, this is, two monopodal (la and lb) and five dipodal (2a, 2b and 3a--3c) aromatic hydrazide derivatives, and the formation of supramolecular polymers and vesicles from the dipodal motifs in hydrocarbons. In this paper, we present a full picture on the properties of these hydrogen-bonding motifs with an emphasis on their self-assembling behaviors in aqueous media. SEM, AFM, TEM and fluorescent micrographs indicate that all the dipodal compounds also form vesicles in polar methanol and water-methanol (up to 50% of water) mixtures. Control experiments show that lb does not form vesicles in same media. Addition of lb to the solution of the dipodal compounds inhibits the latter's capacity of forming vesicles. At high concentrations, 3b and 3c also gelate discrete solvents, including hydrocarbons, esters, methanol, and methanol-water mixture. Concentration-dependent SEM investigations reveal that the vesicles of 3b and 3c fuse to form gels and the gel of 3c can de-aggregate to form the vesicles reversibly.

  7. Data Mining as a Guide for the Construction of Crosslinked Nanoparticles with Low Immunotoxicity via Controlling Polymer Chemistry and Supramolecular Assembly

    Science.gov (United States)

    Elsabahy, Mahmoud; Wooley, Karen L.

    2015-01-01

    CONSPECTUS The potential immunotoxicity of nanoparticles that are currently being approved or in different phases of clinical trials or under rigorous in vitro and in vivo characterizations in several laboratories has recently raised special attention. Products with no apparent in vitro or in vivo toxicity may still trigger the various components of the immune system, unintentionally, and lead to serious adverse reactions. Cytokines are one of the useful biomarkers to predict the effect of biotherapeutics on modulating the immune system and for screening the immunotoxicity of nanoparticles, both in vitro and in vivo, and were found recently to partially predict the in vivo pharmacokinetics and biodistribution of nanomaterials. Control of polymer chemistry and supramolecular assembly provides a great opportunity for construction of biocompatible nanoparticles for biomedical clinical applications. However, the sources of data collected regarding immunotoxicities of nanomaterials are diverse and experiments are usually conducted using different assays and under specific conditions, making direct comparisons nearly impossible and, thus, tailoring properties of nanomaterials based on the available data is challenging. In this account, the effects of chemical structure, crosslinking, degradability, morphology, concentration and surface chemistry on the immunotoxicity of an expansive array of polymeric nanomaterials will be highlighted, with focus being given on assays conducted using the same in vitro and in vivo models and experimental conditions. Furthermore, numerical descriptive values have been utilized, uniquely, to stand for induction of cytokines by nanoparticles. This treatment of available data provides a simple and easy way to compare the immunotoxicity of various nanomaterials, and the values were found to correlate-well with published data. Based on the investigated polymeric systems in this study, valuable information has been collected that aids in the

  8. Coordination of alkaline earth metal ions in the inverted cucurbit[7]uril supramolecular assemblies formed in the presence of [ZnCl4]2- and [CdCl4]2-.

    Science.gov (United States)

    Li, Qing; Zhang, Yun-Qian; Zhu, Qian-Jiang; Xue, Sai-Feng; Tao, Zhu; Xiao, Xin

    2015-05-01

    A convenient method to isolate inverted cucurbit[7]uril (iQ[7]) from a mixture of water-soluble Q[n]s was established by eluting the soluble mixture of Q[n]s on a Dowex (H(+) form) column so that iQ[7] could be selected as a ligand for coordination and supramolecular assembly with alkaline earth cations (AE(2+)) in aqueous HCl solutions in the presence of [ZnCl(4)](2-) and [CdCl(4)](2-) anions as structure-directing agents. Single-crystal X-ray diffraction analysis revealed that both iQ[7]-AE(2+) -[ZnCl(4)](2-) -HCl and iQ[7]-AE(2+) -[CdCl(4)](2-) -HCl interaction systems yielded supramolecular assemblies, in which the [ZnCl(4)](2-) and [CdCl(4)](2-) anions presented a honeycomb effect, and this resulted in the formation of linear iQ[7]/AE(2+) coordination polymers through outer-surface interactions of Q[n]s.

  9. Catalysis of Supramolecular Hydrogelation.

    Science.gov (United States)

    Trausel, Fanny; Versluis, Frank; Maity, Chandan; Poolman, Jos M; Lovrak, Matija; van Esch, Jan H; Eelkema, Rienk

    2016-07-19

    One often thinks of catalysts as chemical tools to accelerate a reaction or to have a reaction run under more benign conditions. As such, catalysis has a role to play in the chemical industry and in lab scale synthesis that is not to be underestimated. Still, the role of catalysis in living systems (cells, organisms) is much more extensive, ranging from the formation and breakdown of small molecules and biopolymers to controlling signal transduction cascades and feedback processes, motility, and mechanical action. Such phenomena are only recently starting to receive attention in synthetic materials and chemical systems. "Smart" soft materials could find many important applications ranging from personalized therapeutics to soft robotics to name but a few. Until recently, approaches to control the properties of such materials were largely dominated by thermodynamics, for instance, looking at phase behavior and interaction strength. However, kinetics plays a large role in determining the behavior of such soft materials, for instance, in the formation of kinetically trapped (metastable) states or the dynamics of component exchange. As catalysts can change the rate of a chemical reaction, catalysis could be used to control the formation, dynamics, and fate of supramolecular structures when the molecules making up these structures contain chemical bonds whose formation or exchange are susceptible to catalysis. In this Account, we describe our efforts to use synthetic catalysts to control the properties of supramolecular hydrogels. Building on the concept of synthesizing the assembling molecule in the self-assembly medium from nonassembling precursors, we will introduce the use of catalysis to change the kinetics of assembler formation and thereby the properties of the resulting material. In particular, we will focus on the synthesis of supramolecular hydrogels where the use of a catalyst provides access to gel materials with vastly different appearance and mechanical

  10. Ordered supramolecular assembly of bis[3,4,12,13,21,22,30, 31-octa(dodecylthio)-2,3-naphthalocyaninato] erbium at the air/water interface

    Institute of Scientific and Technical Information of China (English)

    CHEN; Ya; nli

    2001-01-01

    -type (na)phthalocyaninato and porphyrinato rare earth complexes, Polyhedron, 2000, 19:1381.[12]Jiang. J.. Kasuga, K., Dennis, P. et al., Supramolecular Photosensitive and Electroactive Materials, New York: Academic Press. 2001. 113-210.[13]Van Nostrum. C. F., Nolte, R. J. M., Functional supramolecular material: self-assembly of phthalocyanines and porphyraszines. Chem. Commun., 1996: 2385.[14]Liu. Y., Shigehara, K., Yamada, A., Purification of lutetium diphthalocyanine and electrochromism of its Langmuir-Blodgett films, Thin Solid Films, 1989, 179: 303.[15]Liu. Y.. Shigehara, K., Hara, M. et al., Electrochemistry and electrochromic behavior of Langmuir-Blodgett films of octakis-substituted rare-earth metal diphthalocyanines, J. Am. Chem. Soc., 1991,113: 440.[16]Jones, R., Hunter, R. A., Davidson, K., Ordered Langmuir-Blodgett films of a substituted lutetium bisphthalocyanine, Thin Solid Films,1994, 250: 249.[17]Jones, R., Krier, A., Davidosn, K., Structure electrical conductivity and electrochromism in thin film of substituted and unsubstituted lanthanide bisphthalocyanines, Thin Solid Films, 1997, 298: 228.[18]Qian, D. -J., Liu, H. -G., Jiang, J., Monolayers and Langmuir-Blodgett films of (phthalocyaninato)(tetra-4-pyridylporphyrinato) cerium double-decker heteto complex, Colloids and Surfaces A, 2000,163:191.[19]Honig, E. P., Hengst, J. H. T., Engelsen, D. D., Langmuir-Blodgett deposition ratios, J. Colloid Interface Sci., 1973, 45:92.[20]Smolenyak, P., Peterson, R., Nesesny, K. et al., Highly ordered thin films of octasubstituted phthalocyanines, J. Am. Chem.Soc., 1999, 121: 8628.[21]Kasha, M., Rawls, H. R., E1-Bayoumi, M. A., The excition model in molecular spectroscopy, Pure Appl. Chem., 1965, 11: 371.[22]Fujiki, M., Tabei, H., Kurihara, T., Self-assembling features of soluble nickel phthalocyanines, J. Phys. Chem., 1988, 92:1281.[23]Osburn, E. J., Chau, L. -K., Chen, S. -Y. et al., Novel amphiphilic phthalocyanines

  11. Supramolecular science: A new way to understand the matter world

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xi; SHEN Jiacong

    2003-01-01

    @@ After over 20 years' rapid development, supramolecular chemistry has exceeded the original realm of organic host-guest chemistry, and formed its own unique concepts and systems, such as molecular recognition, molecular self-assembly, supramolecular devices and materials[1,2]. These branches have organized into a charming new subject in the whole family of chemistry.

  12. Supramolecular fibres: Self-sorting shows its true colours

    Science.gov (United States)

    Draper, Emily R.; Adams, Dave J.

    2016-08-01

    Self-sorting events in supramolecular assembly lead to complex systems that are attractive for the design of functional materials, but have remained difficult to understand and control. Now, the growth of self-sorted supramolecular nanofibres has been elucidated by direct imaging through real-time in situ confocal microscopy.

  13. Supramolecular chemistry and crystal engineering

    Indian Academy of Sciences (India)

    Ashwini Nangia

    2010-05-01

    Advances in supramolecular chemistry and crystal engineering reported from India within the last decade are highlighted in the categories of new intermolecular interactions, designed supramolecular architectures, network structures, multi-component host-guest systems, cocrystals, and polymorphs. Understanding self-assembly and crystallization through X-ray crystal structures is illustrated by two important prototypes - the large unit cell of elusive saccharin hydrate, Na16(sac)16 . 30H2O, which contains regular and irregular domains in the same structure, and by the Aufbau build up of zinc phosphate framework structures, e.g. ladder motif in [C3N2H12][Zn(HPO4)2] to layer structure in [C3N2H12][Zn2(HPO4)3] upon prolonged hydrothermal conditions. The pivotal role of accurate X-ray diffraction in supramolecular and structural studies is evident in many examples. Application of the bottomup approach to make powerful NLO and magnetic materials, design of efficient organogelators, and crystallization of novel pharmaceutical polymorphs and cocrystals show possible future directions for interdisciplinary research in chemistry with materials and pharmaceutical scientists. This article traces the evolution of supramolecular chemistry and crystal engineering starting from the early nineties and projects a center stage for chemistry in the natural sciences.

  14. A Supramolecular Hydrogel Inspired by Elastin

    Institute of Scientific and Technical Information of China (English)

    丁磊; 王淑芳; 武文洁; 胡月晗; 杨翠红; 谭鸣; 孔德领; 杨志谋

    2011-01-01

    Self-assembly prevails in nature and learning from nature will lead to biofunctional materials. Inspired by the protein of elastin, we reported in this study on a supramolecular hydrogel beating the elastin repeating peptide of VPGAG. The visco-elasticity property, morphology of the nanostructures, and aromatic stacking in the self-assembled nanostructure were characterized by a rheometry, transmission electron microscope (TEM), and fluorescence microscope, respectively. The biocompatibility of the gelator was also proved by an MTT assay. Though the supramolecular hydrogel failed to exhibit a high elasticity like elastin, the thixotropic hydrogel might have potentials for the applications in fields of cell culture, controlled-drug release, etc.

  15. Identification and characterization of the cDNA sequence encoding amelogenin in rabbit (Oryctolagus cuniculus).

    Science.gov (United States)

    Bai, Chunyan; Li, Yumei; Yan, Shouqing; Fang, Hengtong; Sun, Boxing; Zhang, Jiabao; Zhao, Zhihui

    2016-02-01

    Amelogenins, the most abundant proteins in tooth enamel extracellular matrix (ECM), are essential for tooth amelogenesis. The nucleotide sequence of amelogenin gene (AMEL) for rabbit, as an important member of mammals and good continuously growing incisor model, is important for comparative and evolutional study. Previous studies about rabbit amelogenin proteins got no consensus yet even as to their existence or size. In this study, with combined usage of in silico and molecular cloning technologies, we identified sequences of two transcripts of rabbit amelogenin, resulting from the alternative splicing of the 45-bp exon 4. The coding regions of the two transcripts are of 567- and 522-bp, encoding 188 and 173 amino acids including a 17-residue signal peptide, respectively. Sequence analysis revealed that rabbit amelogenin features in extremely high GC-content in nucleotide sequence and Alanine content in protein sequence. Detailed comparison of amino acid sequence with other mammals showed that the rabbit amelogenin protein is conserved in the sites and regions important for protein functions. Overall, our results uncovered the mysteries about rabbit amelogenin and revealed its sequence peculiarities. PMID:26551300

  16. Three-dimensional hydrogen-bonded supramolecular assembly in tetrakis(1,3,5-triaza-7-phosphaadamantanecopper(I chloride hexahydrate

    Directory of Open Access Journals (Sweden)

    Armando J. L. Pombeiro

    2008-05-01

    Full Text Available The structure of the title compound, [Cu(PTA4]Cl·6H2O (PTA is 1,3,5-triaza-7-phosphaadamantane, C6H12N3P, is composed of discrete monomeric [Cu(PTA4]+ cations, chloride anions and uncoordinated water molecules. The CuI atom exhibits tetrahedral coordination geometry, involving four symmetry-equivalent P–bound PTA ligands. The structure is extended to a regular three-dimensional supramolecular framework via numerous equivalent O—H...N hydrogen bonds between all solvent water molecules (six per cation and all PTA N atoms, thus simultaneously bridging each [Cu(PTA4]+ cation with 12 neighbouring units in multiple directions. The study also shows that PTA can be a convenient ligand in crystal engineering for the construction of supramolecular architectures.

  17. Fibonacci Sequence and Supramolecular Structure of DNA.

    Science.gov (United States)

    Shabalkin, I P; Grigor'eva, E Yu; Gudkova, M V; Shabalkin, P I

    2016-05-01

    We proposed a new model of supramolecular DNA structure. Similar to the previously developed by us model of primary DNA structure [11-15], 3D structure of DNA molecule is assembled in accordance to a mathematic rule known as Fibonacci sequence. Unlike primary DNA structure, supramolecular 3D structure is assembled from complex moieties including a regular tetrahedron and a regular octahedron consisting of monomers, elements of the primary DNA structure. The moieties of the supramolecular DNA structure forming fragments of regular spatial lattice are bound via linker (joint) sequences of the DNA chain. The lattice perceives and transmits information signals over a considerable distance without acoustic aberrations. Linker sequences expand conformational space between lattice segments allowing their sliding relative to each other under the action of external forces. In this case, sliding is provided by stretching of the stacked linker sequences.

  18. Fibonacci Sequence and Supramolecular Structure of DNA.

    Science.gov (United States)

    Shabalkin, I P; Grigor'eva, E Yu; Gudkova, M V; Shabalkin, P I

    2016-05-01

    We proposed a new model of supramolecular DNA structure. Similar to the previously developed by us model of primary DNA structure [11-15], 3D structure of DNA molecule is assembled in accordance to a mathematic rule known as Fibonacci sequence. Unlike primary DNA structure, supramolecular 3D structure is assembled from complex moieties including a regular tetrahedron and a regular octahedron consisting of monomers, elements of the primary DNA structure. The moieties of the supramolecular DNA structure forming fragments of regular spatial lattice are bound via linker (joint) sequences of the DNA chain. The lattice perceives and transmits information signals over a considerable distance without acoustic aberrations. Linker sequences expand conformational space between lattice segments allowing their sliding relative to each other under the action of external forces. In this case, sliding is provided by stretching of the stacked linker sequences. PMID:27265133

  19. Self-Assembly Supramolecular Systems toward Molecular Machines and Motors%具有分子机器、分子开关功能的自组装超分子体系

    Institute of Scientific and Technical Information of China (English)

    陈慧兰

    2001-01-01

    Self-assembly, self-organization and self-replication, that are central to nature' s forms and functions, are now becoming feasible to construct large and intricate, yet highly ordered functioning molecular and supramolecular entities. This paper introduced the recently new progress for a kind of special rotaxane and catenane supramoculars having functions of molecular shuttle or molecular switch, as well as the chemical and biological systems toward molecular machines and motors.%本文介绍了具有分子梭或分子开关性质的新型轮烷和索烃超分子以及具有分子机器功能的其它类型化学和生物分子的国际研究最新动态。

  20. Effects of amelogenins on angiogenesis-associated processes of endothelial cells

    DEFF Research Database (Denmark)

    Almqvist, S; Kleinman, H K; Werthén, M;

    2011-01-01

    To study the effects of an amelogenin mixture on integrin-dependent adhesion, DNA synthesis and apoptosis of cultured human dermal microvascular endothelial cells and angiogenesis in an organotypic assay....

  1. Thermally assisted photonic inversion of supramolecular handedness.

    Science.gov (United States)

    Gopal, Anesh; Hifsudheen, Mohamed; Furumi, Seiichi; Takeuchi, Masayuki; Ajayaghosh, Ayyappanpillai

    2012-10-15

    Spiraling into control: A photoresponsive supramolecular assembly demonstrates that light, along with heating (Δ) and cooling (), can cause chiral communication between molecules. This effect leads to bias in the helicity of the complex, causing a reversible switching of macroscopic handedness, as shown by a reversal of sign of the circularly polarized luminescence (CPL) that is emitted.

  2. Robust excitons inhabit soft supramolecular nanotubes

    NARCIS (Netherlands)

    Eisele, Doerthe M.; Arias, Dylan H.; Fu, Xiaofeng; Bloemsma, Erik A.; Steiner, Colby P.; Jensen, Russell A.; Rebentrost, Patrick; Eisele, Holger; Tokmakoff, Andrei; Lloyd, Seth; Nelson, Keith A.; Nicastro, Daniela; Knoester, Jasper; Bawendi, Moungi G.

    2014-01-01

    Nature's highly efficient light-harvesting antennae, such as those found in green sulfur bacteria, consist of supramolecular building blocks that self-assemble into a hierarchy of close-packed structures. In an effort to mimic the fundamental processes that govern nature's efficient systems, it is i

  3. Amelogenesis Imperfecta and Screening of Mutation in Amelogenin Gene

    Directory of Open Access Journals (Sweden)

    Fernanda Veronese Oliveira

    2014-01-01

    Full Text Available The aim of this study was to report the clinical findings and the screening of mutations of amelogenin gene of a 7-year-old boy with amelogenesis imperfecta (AI. The genomic DNA was extracted from saliva of patient and his family, followed by PCR and direct DNA sequencing. The c.261C>T mutation was found in samples of mother, father, and brother, but the mutation was not found in the sequence of the patient. This mutation is a silent mutation and a single-nucleotide polymorphism (rs2106416. Thus, it is suggested that the mutation found was not related to the clinical presence of AI. Further research is necessary to examine larger number of patients and genes related to AI.

  4. Skeletal ligament healing using the recombinant human amelogenin protein.

    Science.gov (United States)

    Hanhan, Salem; Ejzenberg, Ayala; Goren, Koby; Saba, Faris; Suki, Yarden; Sharon, Shay; Shilo, Dekel; Waxman, Jacob; Spitzer, Elad; Shahar, Ron; Atkins, Ayelet; Liebergall, Meir; Blumenfeld, Anat; Deutsch, Dan; Haze, Amir

    2016-05-01

    Injuries to ligaments are common, painful and debilitating, causing joint instability and impaired protective proprioception sensation around the joint. Healing of torn ligaments usually fails to take place, and surgical replacement or reconstruction is required. Previously, we showed that in vivo application of the recombinant human amelogenin protein (rHAM(+) ) resulted in enhanced healing of the tooth-supporting tissues. The aim of this study was to evaluate whether amelogenin might also enhance repair of skeletal ligaments. The rat knee medial collateral ligament (MCL) was chosen to prove the concept. Full thickness tear was created and various concentrations of rHAM(+) , dissolved in propylene glycol alginate (PGA) carrier, were applied to the transected MCL. 12 weeks after transection, the mechanical properties, structure and composition of transected ligaments treated with 0.5 μg/μl rHAM(+) were similar to the normal un-transected ligaments, and were much stronger, stiffer and organized than control ligaments, treated with PGA only. Furthermore, the proprioceptive free nerve endings, in the 0.5 μg/μl rHAM(+) treated group, were parallel to the collagen fibres similar to their arrangement in normal ligament, while in the control ligaments the free nerve endings were entrapped in the scar tissue at different directions, not parallel to the axis of the force. Four days after transection, treatment with 0.5 μg/μl rHAM(+) increased the amount of cells expressing mesenchymal stem cell markers at the injured site. In conclusion application of rHAM(+) dose dependently induced mechanical, structural and sensory healing of torn skeletal ligament. Initially the process involved recruitment and proliferation of cells expressing mesenchymal stem cell markers. PMID:26917487

  5. Amelogenin: A novel protein with diverse applications in genetic and molecular profiling

    Directory of Open Access Journals (Sweden)

    Ajay Kumar Bansal

    2012-01-01

    Full Text Available Tooth enamel is a unique entity among all mineralized tissues because of the presence of high mineral content. It is non collagenous and does not undergo resorption and remodelling. Its formation occurs through a transient collaborating network of enamel matrix proteins which controls hydroxyapatite crystal growth and orientation. Amelogenins constitute about 90% of the total enamel matrix proteins and play a major role in enamel bio mineralization. Amelogenin isoforms coalesce into nanospheres thus dictating the width and thickness of apatite crystals. The X and Y copies of amelogenins do not undergo homologous recombination, thus preferring it for sex determination in modern forensics. Recently, it was discovered that application of amelogenin to diseased periodontal tissue surfaces enhanced the regeneration of all the periodontal tissues. Additionally, low molecular mass amelogenin polypeptides have also been thought to possess osteogenic potential. Recent data regarding usage of immunohistochemical markers for mesenchymal stem cells suggested that amelogenin has the capacity to induce the recruitment of mesenchymal stem cells directly or indirectly during regeneration of the supporting periodontal tissues. Thus, our current concepts of dental enamel formation should be reviewed thoroughly so that this information could be applied to clinical circumstances where this understanding may be particularly relevant.

  6. Assembly of organic moiety with metal-oxide cluster to generate a new three dimensional supramolecular/hydrogen bonded network based on isopolymolybdate

    Indian Academy of Sciences (India)

    DONIA ZAMMEL; ICHRAF NAGAZI; AMOR HADDAD

    2016-07-01

    A new octa-molybdate formulated as (C₂H₆N₄)₂ [β-Mo₈O₂₆].4H₂O (1) has been isolated by conventional solution method and structurally characterized by single-crystal X-ray diffraction method, IR spectroscopy, UV-Vis absorption, thermogravimetric analysis and cyclic voltammetry. Compound 1 crystallizes in the Triclinic system, space group P-1 with unit cell dimensions, a = 8.348 (2)Å, b = 10.154 (2)Å, c = 10.823 (3)Å, α = 68.35◦ (2), β = 71.59◦ (2), γ= 78.55◦ (2), V = 805.5 (3)ų, and Z = 2. The crystal structure of 1 is built up from octa-molybdate [β-Mo₈O₂₆]⁴⁻ clusters connected through hydrogen-bonding interactions into a three-dimensional supramolecular network.

  7. New Supramolecular Complex Assembled through Hydrogen Bonds.Crystal Structure of Co(PMBP-tsc)2·2DMF·2H2O

    Institute of Scientific and Technical Information of China (English)

    UU,Lang(刘浪); JIA,Dian-Zeng(贾殿赠); QIAO,Yong-Min(乔永民); YU,Kai-Bei(郁开北)

    2002-01-01

    The structure of the complex [Co(PMBP-tsc)2.2DMF@2H2O]( PMBP-tsc= 1-phenyl-3-methyl-4-benzoylpyrazol-5-one-thiosemicarbazone) has been determined by X-ray crystallography. It crystallizes in the orthorhombic system, space group Pna21, with lattice parameters a=2.1170(3) nm, b =1.2780(10) nm, c = 1.8956(2) nm, V= 4.5258(9) nm3 and Z=4. The structure shows that Co2+ in the complex is hexacoordinated with a distorted octahedral coordination sphere.The water molecules bridge the adjacent stacks through hydrogen bonds and lead to supramolecular formation with three-dimensional network structure.

  8. Energy landscapes and functions of supramolecular systems

    Science.gov (United States)

    Tantakitti, Faifan; Boekhoven, Job; Wang, Xin; Kazantsev, Roman V.; Yu, Tao; Li, Jiahe; Zhuang, Ellen; Zandi, Roya; Ortony, Julia H.; Newcomb, Christina J.; Palmer, Liam C.; Shekhawat, Gajendra S.; de La Cruz, Monica Olvera; Schatz, George C.; Stupp, Samuel I.

    2016-04-01

    By means of two supramolecular systems--peptide amphiphiles engaged in hydrogen-bonded β-sheets, and chromophore amphiphiles driven to assemble by π-orbital overlaps--we show that the minima in the energy landscapes of supramolecular systems are defined by electrostatic repulsion and the ability of the dominant attractive forces to trap molecules in thermodynamically unfavourable configurations. These competing interactions can be selectively switched on and off, with the order of doing so determining the position of the final product in the energy landscape. Within the same energy landscape, the peptide-amphiphile system forms a thermodynamically favoured product characterized by long bundled fibres that promote biological cell adhesion and survival, and a metastable product characterized by short monodisperse fibres that interfere with adhesion and can lead to cell death. Our findings suggest that, in supramolecular systems, functions and energy landscapes are linked, superseding the more traditional connection between molecular design and function.

  9. A combined experimental and theoretical study of the supramolecular self-assembly of Cu(II) malonate complex assisted by various weak forces and water dimer

    International Nuclear Information System (INIS)

    A Cu(II) malonate complex with formula [Cu(C3H2O4)(C6H8N2)(H2O)]2·4H2O (1) [C6H8N2=2-picolylamine, C3H2O42−=malonate dianion] has been synthesized by mixing the reactants in their stoichiometric proportion and its crystal structure has been determined by single-crystal X-ray diffraction. In 1, monomeric neutral metal malonate units [Cu(C3H2O4)(C6H8N2)(H2O)] are interlinked with each other through hydrogen bonds, weak lone pair⋯π and cuprophilic interactions to generate supramolecular dimers, which in turn further associated through hydrogen bonding to form infinite 1D chains. Water dimers, through series of hydrogen bonds and weak π–stacking forces are found to be responsible for interconnection of 1D chains, which resulted in a 3D network. A density functional (DFT) study of the energetic features of several noncovalent interactions observed in the solid state have been analyzed and characterized using Bader's theory of “atoms-in-molecules”. We also present here Hirshfeld surface analysis to investigate the close intermolecular contacts. - Graphical Abstract: Interplay of weak forces like hydrogen bonding, lone pair⋯π, Cu⋯Cu and π–stacking interactions leading to the formation of supramolecular network in [Cu(C3H2O4)(C6H8N2)(H2O)]2·4H2O complex. - Highlights: • A complex of Cu(II) with malonate and 2-picolylamine is synthesized and X-ray characterized. • We report a density functional study of the energetic features of several noncovalent interactions • We perform Hirshfeld surface analysis to investigate the close intermolecular contacts

  10. The human enamel protein gene amelogenin is expressed from both the X and the Y chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Salido, E.C. (Faculty of Medicine, La Laguna (Spain)); Yen, P.H.; Koprivnikar, K.; Shapiro, L.J. (University of California School of Medicine, Torrence (United States)); Yu, Lohchung (Lawrence Livermore National Laboratory, CA (United States))

    1992-02-01

    Amelogenins, a family of extracellular matrix proteins of the dental enamel, are transiently but abundantly expressed by ameloblasts during tooth development. In this paper the authors report the characterization of the AMGX and AMGY genes on the short arms of the human X and Y chromosomes which encode the amelogenins. Their studies on the expression of the amelogenin genes in male developing tooth buds showed that both the AMGX and AMGY genes are transcriptionally active and encode potentially functional proteins. They have isolated genomic and cDNA clones form both the AMGX and AMGY loci and have studied the sequence organization of these two genes. Reverse transcriptase (RT)PCR amplification of the 5[prime] portion of the amelogenin transcripts revealed several alternatively spliced products. This information will be useful for studying the molecular basis of X-linked amelogenesis imperfecta, for understanding the evolution and regulation of gene expression on the mammalian sex chromosomes, and for investigating the role of amelogenin genes during tooth development.

  11. Preface to the special issue: Macrocyclic and supramolecular chemistry

    Institute of Scientific and Technical Information of China (English)

    LIU Yu

    2009-01-01

    @@ The 14th Conference of Macrocyclic Chemistry and the 6th Conference of Supramolecular Chemistry was held in Northwest Normal University in Lanzhou, Gansu Province, China, from 11 to 13 August, 2008. More than 200 participants from 40 universities and institutes dis-cussed the development of macrocyclic and su-pramolecular chemistry in China. More than 50 plenary and oral presentations concerning the synthesis, recogni-tion, assembly and functions of macrocyclic and su-pramolecular systems were held, presenting significant achievements in these areas.

  12. Supramolecular control of [2 + 2] photodimerization via hydrogen bonding.

    Science.gov (United States)

    Darcos, Vincent; Griffith, Kirsten; Sallenave, Xavier; Desvergne, Jean-Pierre; Guyard-Duhayon, Carine; Hasenknopf, Bernold; Bassani, Dario M

    2003-11-01

    The use of supramolecular catalysis to control the photoinduced dimerization of styrene, cinnamate, and stilbene chromophores is reported. The strategy employs the formation of a 2:1 supramolecular assembly in the presence of 5,5-dihexylbarbituric acid (DHB). A 3- to 10-fold increase in dimerization efficiency is observed in its presence, concomitant with accrued selectivity for the syn photodimers. The origin of the regioselectivity in the presence of DHB is discussed in terms of topochemical control within the supramolecular architecture. PMID:14690228

  13. Simulation of self-organization processes in crystal-forming systems: Supramolecular cyclic R6 cluster precursors and self-assembly of TeO2- TEL ( Tellurite) and TeO2- PAR ( Paratellurite) structures

    Science.gov (United States)

    Ilyushin, G. D.

    2014-11-01

    The supramolecular chemistry of oxides of sp elements (SO2, SeO2, and TeO2) is considered. The self-assembly of TeO2- TEL ( Tellurite) and TeO2- PAR ( Paratellurite) crystal structures is simulated. Methods of combinatorial and topological analysis (TOPOS program package) are applied which are based on constructing a basis 3D network of the structure in the form of a graph, the sites of which correspond to the positions of centroids of TeO2 molecules and the edges characterize bonds between them. The topological type of the basis 2D network in the TeO2- TEL structure corresponds to graphite (C- GRA), while in the TeO2- PAR structure the basis network corresponds to the 3D diamond network (C- DIA). A nanocluster precursor of cyclic type ( R6) composed of six covalently bound TeO2 molecules (chair conformation) is established for both structures. The desymmetrization of the cyclic structure of the R6 cluster in TeO2- PAR is related to the formation of Te-Te bonds with lengths of 3.824 and 4.062 Å. The symmetry and topology code of the processes of self-assembly of 3D structures from nanocluster precursors is completely reconstructed into the form "primary chain → microlayer → microframework." In both structures R6 clusters form 2D packings with a coordination number of 6. The cluster self-assembly model explains the specific features of the morphogenesis of TeO2- TEL and TeO2- PAR (phases with low and high crystallization temperatures, respectively): platelike shape, perfect cleavage in the (110) plane, and preferred growth in the primar-chain direction [100] in the former case and growth in the direction of the primary [001] axis with the preferred formation of tetragonal prism faces (110) in the latter case.

  14. A combined experimental and theoretical study of the supramolecular self-assembly of Cu(II) malonate complex assisted by various weak forces and water dimer

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Prankrishna [Department of Chemistry, Jadavpur University, Kolkata 700 032 (India); Ray Choudhury, Somnath [Central Chemical Laboratory, Geological Survey of India, 15 A and B Kyd Street, Kolkata 700 016 (India); Mitra, Monojit [Department of Chemistry, Jadavpur University, Kolkata 700 032 (India); Kumar Seth, Saikat [Department of Physics, M. G. Mahavidyalaya, Bhupatinagar, Purba Medinipur, West Bengal 721 425 (India); Helliwell, Madeleine [School of Chemistry, The University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Bauzá, Antonio [Departament de Química, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122 Palma (Baleares) (Spain); Frontera, Antonio, E-mail: toni.frontera@uib.es [Departament de Química, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122 Palma (Baleares) (Spain); Mukhopadhyay, Subrata, E-mail: smukhopadhyay@chemistry.jdvu.ac.in [Department of Chemistry, Jadavpur University, Kolkata 700 032 (India)

    2014-12-15

    A Cu(II) malonate complex with formula [Cu(C{sub 3}H{sub 2}O{sub 4})(C{sub 6}H{sub 8}N{sub 2})(H{sub 2}O)]{sub 2}·4H{sub 2}O (1) [C{sub 6}H{sub 8}N{sub 2}=2-picolylamine, C{sub 3}H{sub 2}O{sub 4}{sup 2−}=malonate dianion] has been synthesized by mixing the reactants in their stoichiometric proportion and its crystal structure has been determined by single-crystal X-ray diffraction. In 1, monomeric neutral metal malonate units [Cu(C{sub 3}H{sub 2}O{sub 4})(C{sub 6}H{sub 8}N{sub 2})(H{sub 2}O)] are interlinked with each other through hydrogen bonds, weak lone pair⋯π and cuprophilic interactions to generate supramolecular dimers, which in turn further associated through hydrogen bonding to form infinite 1D chains. Water dimers, through series of hydrogen bonds and weak π–stacking forces are found to be responsible for interconnection of 1D chains, which resulted in a 3D network. A density functional (DFT) study of the energetic features of several noncovalent interactions observed in the solid state have been analyzed and characterized using Bader's theory of “atoms-in-molecules”. We also present here Hirshfeld surface analysis to investigate the close intermolecular contacts. - Graphical Abstract: Interplay of weak forces like hydrogen bonding, lone pair⋯π, Cu⋯Cu and π–stacking interactions leading to the formation of supramolecular network in [Cu(C{sub 3}H{sub 2}O{sub 4})(C{sub 6}H{sub 8}N{sub 2})(H{sub 2}O)]{sub 2}·4H{sub 2}O complex. - Highlights: • A complex of Cu(II) with malonate and 2-picolylamine is synthesized and X-ray characterized. • We report a density functional study of the energetic features of several noncovalent interactions • We perform Hirshfeld surface analysis to investigate the close intermolecular contacts.

  15. Enzymatic induction of supramolecular order and bioactivity

    Science.gov (United States)

    Yang, Chengbiao; Ren, Xinrui; Ding, Dan; Wang, Ling; Yang, Zhimou

    2016-05-01

    We showed in this study that enzymatic triggering is a totally different pathway for the preparation of self-assembling nanomaterials to the heating-cooling process. Because the molecules were under lower energy levels and the molecular conformation was more ordered during the enzymatic triggeration under mild conditions, nanomaterials with higher supramolecular order could be obtained through biocatalytic control. In this study, nanoparticles were obtained by an enzymatic reaction and nanofibers were observed through the heating-cooling process. We observed a distinct trough at 318 nm from the CD spectrum of a particle sample but not a fiber sample, suggesting the long range arrangement of molecules and helicity in the nanoparticles. The nanoparticles with higher supramolecular order possessed much better potency as a protein vaccine adjuvant because it accelerated the DC maturation and elicited stronger T-cells cytokine production than the nanofibers. Our study demonstrated that biocatalytic triggering is a useful method for preparing supramolecular nanomaterials with higher supramolecular order and probably better bioactivity.We showed in this study that enzymatic triggering is a totally different pathway for the preparation of self-assembling nanomaterials to the heating-cooling process. Because the molecules were under lower energy levels and the molecular conformation was more ordered during the enzymatic triggeration under mild conditions, nanomaterials with higher supramolecular order could be obtained through biocatalytic control. In this study, nanoparticles were obtained by an enzymatic reaction and nanofibers were observed through the heating-cooling process. We observed a distinct trough at 318 nm from the CD spectrum of a particle sample but not a fiber sample, suggesting the long range arrangement of molecules and helicity in the nanoparticles. The nanoparticles with higher supramolecular order possessed much better potency as a protein vaccine

  16. Single-step coacervate-mediated preconcentration of metals and metal-chelates in supramolecular vesicular surfactant assemblies and determination by flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tsogas, George Z. [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece); Giokas, Dimosthenis L. [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece)]. E-mail: dgiokas@cc.uoi.gr; Paleologos, Evangelos K. [Laboratory of Food Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece); Vlessidis, Athanasios G. [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece); Evmiridis, Nicholaos P. [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece)

    2005-04-29

    The use of ionic surfactant supramolecular aggregates is described, as means for accomplishing the concentration of analytes with different polarities using the same extraction pattern. The proposed method is based on the phase separation of an anionic surfactant through the formation of perplexed lamellar phases, allowing for the extraction of hydrated metal cations by complexation and metal-chelates by hydrophobic interactions. The data suggest that both extraction and phase separation are controlled by the presence of ionic surfactant as a function of the degree of phase divergence from the lamellar to bilayer phase. This again is determined by the composition of the phase-forming parameters, these are the surfactant concentration, the kind and amount of metallic counterparts and ionic strength. On the basis of these findings, the proposed method was successfully applied to the determination of metal species in natural waters. The limits of detection were easily brought down to the low microgram per liter levels by simply preconcentrating 10 mL of sample volume in the presence of at least 0.45% (w/v) of anionic surfactant. The method provided extraction recoveries higher than 94.0% with standard deviations well below 7.0%.

  17. Supramolecular Langmuir monolayers and multilayered vesicles of self-assembling DNA–lipid surface structures and their further implications in polyelectrolyte-based cell transfections

    Energy Technology Data Exchange (ETDEWEB)

    Demirsoy, Fatma Funda Kaya [Ankara University, The Central Laboratory of The Institute of Biotechnology (Turkey); Eruygur, Nuraniye [Gazi University, Department of Pharmacognosy, Faculty of Pharmacy (Turkey); Süleymanoğlu, Erhan, E-mail: erhans@mail.ru [Gazi University, Department of Pharmaceutical Chemistry, Faculty of Pharmacy (Turkey)

    2015-01-15

    The basic interfacial characteristics of DNA–lipid recognitions have been studied. The complex structures of individual unbound DNA molecules and their binary and ternary complexes with zwitterionic lipids and divalent cations were followed by employing lipid monolayers at the air–liquid interfaces, as well as by performing various microscopic, spectroscopic, and thermodynamic measurements with multilayered vesicles. The pressure-area isotherms depicted that Mg{sup 2+}-ions increase the surface pressure of lipid films and thus give rise to electrostatic and hydrophobic lipid–DNA interactions in terms of DNA adsorption, adhesion, and compaction. These features were further approached by using multilamellar vesicles with a mean diameter of 850 nm, where a metal ion-directed nucleic acid compaction and condensation effects were shown. The data obtained show the effectiveness of Langmuir monolayers and lipid multilayers in studying nucleic acid–lipid recognitions. The data provide with further details and support previous reports on mainly structural features of these recognitions. Biomolecular surface recognition events were presented in direct link with spectral and thermodynamic features of lipid vesicle–polynucleotide complex formations. The results serve to build a theoretical model considering the use of neutral lipids in lipoplex designs as a polyelectrolyte alternatives to the currently employed cytotoxic cationic liposomes. The supramolecular structures formed and their possible roles in interfacial electrostatic and hydrophobic mechanisms of endosomal escape in relevant cell transfection assays are particularly emphasized.

  18. Redox-Robust Pentamethylferrocene Polymers and Supramolecular Polymers, and Controlled Self-Assembly of Pentamethylferricenium Polymer-Embedded Ag, AgI, and Au Nanoparticles.

    Science.gov (United States)

    Gu, Haibin; Ciganda, Roberto; Castel, Patricia; Vax, Amélie; Gregurec, Danijela; Irigoyen, Joseba; Moya, Sergio; Salmon, Lionel; Zhao, Pengxiang; Ruiz, Jaime; Hernández, Ricardo; Astruc, Didier

    2015-12-01

    We report the first pentamethylferrocene (PMF) polymers and the redox chemistry of their robust polycationic pentamethylferricenium (PMFium) analogues. The PMF polymers were synthesized by ring-opening metathesis polymerization (ROMP) of a PMF-containing norbornene derivative by using the third-generation Grubbs ruthenium metathesis catalyst. Cyclic voltammetry studies allowed us to determine confidently the number of monomer units in the polymers through the Bard-Anson method. Stoichiometric oxidation by using ferricenium hexafluorophosphate quantitatively and instantaneously provided fully stable (even in aerobic solutions) blue d(5) Fe(III) metallopolymers. Alternatively, oxidation of the PMF-containing polymers was conducted by reactions with Ag(I) or Au(III) , to give PMFium polymer-embedded Ag and Au nanoparticles (NPs). In the presence of I2 , oxidation by using Ag(I) gave polymer-embedded Ag/AgI NPs and AgNPs at the surface of AgI NPs. Oxidation by using Au(III) also produced an Au(I) intermediate that was trapped and characterized. Engineered single-electron transfer reactions of these redox-robust nanomaterial precursors appear to be a new way to control their formation, size, and environment in a supramolecular way.

  19. Preferential and selective degradation and removal of amelogenin adsorbed on hydroxyapatites by MMP20 and KLK4 in vitro

    Directory of Open Access Journals (Sweden)

    Li eZhu

    2014-07-01

    Full Text Available The hardest tooth enamel tissue develops from a soft layer of protein-rich matrix, predominated by amelogenin that is secreted by epithelial ameloblasts in the secretory stage of tooth enamel development. During enamel formation, a well-controlled progressive removal of matrix proteins by resident proteases, MMP20 and KLK4, will provide space for the apatite crystals to grow. To better understand the role of amelogenin degradation in enamel biomineralization, the present study was conducted to investigate how the adsorption of amelogenin to HAP crystals affects its degradation by enamel proteinases, MMP20 and KLK4. Equal quantities of amelogenins confirmed by protein assays before digestions, either adsorbed to HAP or in solution, were incubated with MMP20 or KLK4. The digested samples collected at different time points were analyzed by spectrophotometry, SDS-PAGE, HPLC and LC/MALDI MS/MS. We found that majority of amelogenin adsorbed on HAP was released into the surrounding solution by enzymatic processing (88% for MMP20 and 98% for KLK4. The results show that as compared with amelogenin in solution, the HAP-bound amelogenin was hydrolyzed by both MMP20 and KLK4 at significantly higher rates. Using LC/MALDI MS-MS, more accessible cleavage sites and hydrolytic fragments from MMP20/KLK4 digestion were identified for the amelogenin adsorbed on HAP crystals as compared to the amelogenin in solution. These results suggest that the adsorption of amelogenin to HAP results in their preferential and selective degradation and removal from HAP by MMP20 and KLK4 in vitro. Based on these findings, a new degradation model related to enamel crystal growth is proposed.

  20. Hydrogen bonded supramolecular structures

    CERN Document Server

    Li, Zhanting

    2015-01-01

    This book covers the advances in the studies of hydrogen-bonding-driven supramolecular systems  made over the past decade. It is divided into four parts, with the first introducing the basics of hydrogen bonding and important hydrogen bonding patterns in solution as well as in the solid state. The second part covers molecular recognition and supramolecular structures driven by hydrogen bonding. The third part introduces the formation of hollow and giant macrocycles directed by hydrogen bonding, while the last part summarizes hydrogen bonded supramolecular polymers. This book is designed to b

  1. 超分子化合物的合成自组装应用研究的新进展%Recent Research Achievements on Synthesis and Self-assembly Applications of New Supramolecular Compounds

    Institute of Scientific and Technical Information of China (English)

    张来新; 赵卫星

    2013-01-01

    简要介绍了超分子化学的产生、发展及应用,重点介绍了:①新型超分子化合物的合成及自组装;②新型超分子金属配合物的合成及应用;③新型超分子化合物的合成及药理作用。并对超分子化学的发展进行了展望。%This paper briefly introduces the generation ,development,and application of supramolecular chemis-try.Emphases are put on three parts:①synthesis and applications of new supramolecular compounds;②synthesis and applications of new supramolecular metal complexes;③synthesis and pharmacological effects of new supramo-lecular compounds.Future developments of supramolecular chemistry are prospected in the end.

  2. Molecular and supramolecular control of the work function of an inorganic electrode with self-assembled monolayer of umbrella-shaped fullerene derivatives.

    Science.gov (United States)

    Lacher, Sebastian; Matsuo, Yutaka; Nakamura, Eiichi

    2011-10-26

    The surface properties of inorganic substrates can be altered by coating with organic molecules, which may result in the improvement of the properties suitable for electronic or biological applications. This article reports a systematic experimental study on the influence of the molecular and supramolecular properties of umbrella-shaped penta(organo)[60]fullerene derivatives, and on the work function and the water contact angle of indium-tin oxide (ITO) and gold surfaces. We could relate these macroscopic characteristics to single-molecular level properties, such as ionization potential and molecular dipole. The results led us to conclude that the formation of a SAM of a polar compound generates an electronic field through intermolecular interaction of the molecular charges, and this field makes the overall dipole of the SAM much smaller than the one expected from the simple sum of the dipoles of all molecules in the SAM. This effect, which was called depolarization and previously discussed theoretically, is now quantitatively probed by experiments. The important physical properties in surface science such as work function, ionization potential, and water contact angles have been mutually correlated at the level of molecular structures and molecular orientations on the substrate surface. We also found that the SAMs on ITO and gold operate under the same principle except that the "push-back" effect operates specifically for gold. The study also illustrates the ability of the photoelectron yield spectroscopy technique to rapidly measure the work function of a SAM-covered substrate and the ionization potential value of a molecule on the surface. PMID:21923177

  3. Supramolecular Photodimerization of Coumarins

    Directory of Open Access Journals (Sweden)

    Koichi Tanaka

    2012-02-01

    Full Text Available Stereoselective photodimerization of coumarin and its derivatives in supra-molecular systems is reviewed. The enantioselective photodimerization of coumarin and thiocoumarin in inclusion crystals with optically active host compounds is also described.

  4. A One-Pot Self-Assembly Reaction to Prepare a Supramolecular Palladium(II) Cyclometalated Complex: An Undergraduate Organometallic Laboratory Experiment

    Science.gov (United States)

    Fernandez, Alberto; Lopez-Torres, Margarita; Fernandez, Jesus J.; Vazquez-Garcia, Digna; Vila, Jose M.

    2012-01-01

    A laboratory experiment for students in advanced inorganic chemistry is described. Students prepare palladium(II) cyclometalated complexes. A terdentate [C,N,O] Schiff base ligand is doubly deprotonated upon reaction with palladium(II) acetate in a self-assembly process to give a palladacycle with a characteristic tetranuclear structure. This…

  5. Supramolecular photochemistry and solar cells

    Directory of Open Access Journals (Sweden)

    IHA NEYDE YUKIE MURAKAMI

    2000-01-01

    Full Text Available Supramolecular photochemistry as well as solar cells are fascinating topics of current interest in Inorganic Photochemistry and very active research fields which have attracted wide attention in last two decades. A brief outline of the investigations in these fields carried out in our Laboratory of Inorganic Photochemistry and Energy Conversion is given here with no attempt of an exhaustive coverage of the literature. The emphasis is placed on recent work and information on the above mentioned subjects. Three types of supramolecular systems have been the focus of this work: (i cage-type coordination compounds; (ii second-sphere coordination compounds, exemplified by ion-pair photochemistry of cobalt complexes and (iii covalently-linked systems. In the latter, modulation of the photoluminescence and photochemistry of some rhenium complexes are discussed. Solar energy conversion and development of thin-layer photoelectrochemical solar cells based on sensitization of nanocrystalline semiconductor films by some ruthenium polypyridyl complexes are presented as an important application that resulted from specifically engineered artificial assemblies.

  6. Tooth Enamel Protein Amelogenin Binds to Ameloblast Cell Membrane-Mimicking Vesicles via its N-terminus

    Science.gov (United States)

    LOKAPPA, SOWMYA BEKSHE; CHANDRABABU, KARTHIK BALAKRISHNA; MORADIAN-OLDAK, JANET

    2015-01-01

    We have recently reported that the extracellular enamel protein amelogenin has affinity to interact with phospholipids and proposed that such interactions may play key roles in enamel biomineralization as well as reported amelogenin signaling activities. Here, in order to identify the liposome-interacting domains of amelogenin we designed four different amelogenin mutants containing only a single tryptophan at positions 25, 45, 112 and 161. Circular dichroism studies of the mutants confirmed that they are structurally similar to the wild-type amelogenin. Utilizing the intrinsic fluorescence of single tryptophan residues and fluorescence resonance energy transfer FRET, we analyzed the accessibility and strength of their binding with an ameloblast cell membrane-mimicking model membrane (ACML) and a negatively charged liposome used as a membrane model. We found that amelogenin has membrane-binding ability mainly via its N-terminal, close to residues W25 and W45. Significant blue shift was also observed in the fluorescence of a N-terminal peptide following addition of liposomes. We suggest that, among other mechanisms, enamel malformation in cases of Amelogenesis Imperfecta (AI) with mutations at the N-terminal may be the result of defective amelogenin-cell interactions. PMID:26188506

  7. Versatile Supramolecular Gene Vector Based on Host-Guest Interaction.

    Science.gov (United States)

    Liu, Jia; Hennink, Wim E; van Steenbergen, Mies J; Zhuo, Renxi; Jiang, Xulin

    2016-04-20

    It is a great challenge to arrange multiple functional components into one gene vector system to overcome the extra- and intracellular obstacles for gene therapy. In this study, we developed a supramolecular approach for constructing a versatile gene delivery system composed of adamantyl-terminated functional polymers and a β-cyclodextrin based polymer. Adamantyl-functionalized low molecular weight PEIs (PEI-Ad) and PEG (Ad-PEG) as well as poly(β-cyclodextrin) (PCD) were synthesized by one-step chemical reactions. The supramolecular inclusion complex formed from PCD to assemble LMW PEI-Ad4 via host-guest interactions can condense plasmid DNA to form nanopolyplexes by electrostatic interactions. The supramolecular polyplexes can be further PEGylated with Ad-PEG to form inclusion complexes, which showed increased salt and serum stability. In vitro experiments revealed that these supramolecular assembly polyplexes had good cytocompatibility and showed high transfection activity close to that of the commercial ExGen 500 at high dose of DNA. Also, the supramolecular vector system exhibited about 60% silencing efficiency as a siRNA vector. Thus, a versatile effective supramolecular gene vector based on host-guest complexes was fabricated with good cytocompatbility and transfection activity. PMID:27019340

  8. Supramolecular Luminescence from Oligofluorenol-Based Supramolecular Polymer Semiconductors

    OpenAIRE

    Guang-Wei Zhang; Long Wang; Ling-Hai Xie; Jin-Yi Lin; Wei Huang

    2013-01-01

    Supramolecular luminescence stems from non-covalent exciton behaviors of active π-segments in supramolecular entities or aggregates via intermolecular forces. Herein, a π-conjugated oligofluorenol, containing self-complementary double hydrogen bonds, was synthesized using Suzuki coupling as a supramolecular semiconductor. Terfluorenol-based random supramolecular polymers were confirmed via concentration-dependent nuclear magnetic resonance (NMR) and dynamic light scattering (DLS). The photolu...

  9. Ag+ labeling: a convenient new tool for the characterization of hydrogen-bonded supramolecular assemblies by MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Timmerman, P; Jolliffe, K A; Calama, M C; Weidmann, J L; Prins, L J; Cardullo, F; Snellink-Ruël, B H; Fokkens, R H; Nibbering, N M; Shinkai, S; Reinhoudt, D N

    2000-11-17

    Herein we describe our results on the characterization of a wide variety of different hydrogen-bonded assemblies by means of a novel matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) technique with Ag+ labeling. The labeling technique with Ag+ ions is extremely mild and provides a nondestructive way to generate charged assemblies that can be detected by mass spectrometry. Up to now more than 25 different single (1(3).2(3)), double (3(3).2(6)), and tetrarosettes (4(3).2(12)) have been successfully characterized by the use of this method. The success of the method entirely depends on the presence of a suitable binding site for the Ag+ ion. A variety of functionalities has been identified that provide strong binding sites for Ag+, either acting in a cooperative way (pi-arene and pi-alkene donor functionalities) or individually (cyano and crown ether functionalities). The method works well for assemblies with molecular weights between 2,000 and 8,000 Da, and most likely far beyond this limit.

  10. Topical application of amelogenin extracellular matrix protein in non-healing venous ulcers

    Directory of Open Access Journals (Sweden)

    Burçin Abud

    2014-12-01

    Full Text Available Background and Design: Treatment of chronic venous ulcers of the lower extremity is still an important difficulty. The principal treatment of these ulcers includes compression therapy, local wound care and surgery. Unresponsiveness to these standard treatments is a frequent situation with negative effects on life quality and reductions in personal productivity. Therefore, there is a need for new applications to increase the effectiveness of treatment in treatment-resistant cases. In the present study, we retrospectively evaluated the results of topical application of amelogenin extracellular matrix protein in resistant venous ulcers. Materials and Methods: We analyzed the records of patients with treatment-resistant venous ulceration who were treated with amelogenin extracellular matrix protein between June 2011 and December 2012.. Results: 26 patients (21 male and 5 female with a total number of 28 ulcers (24 patients with 1 ulcer, 2 patients with two ulcers were evaluated. The patients were treated with topically applied amelogenin extracellular matrix protein and regional four bandage compression. Bandages were changed weekly. Each cure continued for six weeks. In fourteen patients (15 ulcers, we observed a complete healing by the end of the first cure. In another twelve cases (13 ulcers, the same period resulted with a reduction in wound diameter. We continued to the second cure for these patients. By the end of the second cure, complete healing was achieved in five cases (6 ulcers. Conclusion: Topical application of amelogenin extracellular matrix protein may be considered as an effective therapeutic choice for refractory venous ulcers.

  11. Mineral Association Changes the Secondary Structure and Dynamics of Murine Amelogenin

    Energy Technology Data Exchange (ETDEWEB)

    Lu, J. X.; Xu, Y. S.; Buchko, G. W.; Shaw, W. J.

    2013-10-15

    Biomineralization proteins, present during the formation of hard tissues including bones, teeth, egg shells and nacre, result in the exquisite structures and properties of the resulting materials.[1] The structure of these proteins is often implicated in the control of the mineral properties, however very little structural data is available for the bulk of these proteins due to the difficulty in determining structures of immobilized proteins. Solid-state NMR is uniquely suited to the study of the structure of proteins bound to surfaces, demonstrated with the structural and orientation insights provided for the hydroxyapatite mineralization proteins statherin and the amelogenin, LRAP.[2] While these data are some of the only structural data available for this important class of protein, the experiments are often expensive and time consuming, due to the need to prepare and measure samples with isolated spin pairs, and are limited to a size of ~60 residues. In this work, we utilized a combination of 1D and recent 2D[3] solid-state NMR techniques along with a sparsely labelled sample to characterize the structure and dynamics of potential HAP binding residues of the 180 residue enamel protein, amelogenin. Amelogenin nanospheres and mineral bound amelogenin were investigated and a shift from unstructured to β-sheet structure was observed, along with a decrease in protein flexibility. This work provides the first molecular level structure and dynamic information of full-length amelogenin on the surface of hydroxyapatite (HAP) and within nanospheres, and demonstrates the ability to evaluate structural characteristics of large biomineralization proteins bound to their physiologically relevant surface. The research was performed at the Pacific Northwest National Laboratory (PNNL), a facility operated by Battelle for the U.S. Department of Energy, with a portion of it performed at the W.R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user

  12. Supramolecular Luminescence from Oligofluorenol-Based Supramolecular Polymer Semiconductors

    Directory of Open Access Journals (Sweden)

    Guang-Wei Zhang

    2013-11-01

    Full Text Available Supramolecular luminescence stems from non-covalent exciton behaviors of active π-segments in supramolecular entities or aggregates via intermolecular forces. Herein, a π-conjugated oligofluorenol, containing self-complementary double hydrogen bonds, was synthesized using Suzuki coupling as a supramolecular semiconductor. Terfluorenol-based random supramolecular polymers were confirmed via concentration-dependent nuclear magnetic resonance (NMR and dynamic light scattering (DLS. The photoluminescent spectra of the TFOH-1 solution exhibit a green emission band (g-band at approximately ~520 nm with reversible features, as confirmed through titration experiments. Supramolecular luminescence of TFOH-1 thin films serves as robust evidence for the aggregates of g-band. Our results suggest that the presence of polyfluorene ketone defects is a sufficient condition, rather than a sufficient-necessary condition for the g-band. Supramolecular electroluminescence will push organic devices into the fields of supramolecular optoelectronics, spintronics, and mechatronics.

  13. Controlling and imaging biomimetic self-assembly

    Science.gov (United States)

    Aliprandi, Alessandro; Mauro, Matteo; de Cola, Luisa

    2016-01-01

    The self-assembly of chemical entities represents a very attractive way to create a large variety of ordered functional structures and complex matter. Although much effort has been devoted to the preparation of supramolecular nanostructures based on different chemical building blocks, an understanding of the mechanisms at play and the ability to monitor assembly processes and, in turn, control them are often elusive, which precludes a deep and comprehensive control of the final structures. Here the complex supramolecular landscape of a platinum(II) compound is characterized fully and controlled successfully through a combination of supramolecular and photochemical approaches. The supramolecular assemblies comprise two kinetic assemblies and their thermodynamic counterpart. The monitoring of the different emission properties of the aggregates, used as a fingerprint for each species, allows the real-time visualization of the evolving self-assemblies. The control of multiple supramolecular pathways will help the design of complex systems in and out of their thermodynamic equilibrium.

  14. Supramolecular Nanoparticles for Molecular Diagnostics and Therapeutics

    Science.gov (United States)

    Chen, Kuan-Ju

    Over the past decades, significant efforts have been devoted to explore the use of various nanoparticle-based systems in the field of nanomedicine, including molecular imaging and therapy. Supramolecular synthetic approaches have attracted lots of attention due to their flexibility, convenience, and modularity for producing nanoparticles. In this dissertation, the developmental story of our size-controllable supramolecular nanoparticles (SNPs) will be discussed, as well as their use in specific biomedical applications. To achieve the self-assembly of SNPs, the well-characterized molecular recognition system (i.e., cyclodextrin/adamantane recognition) was employed. The resulting SNPs, which were assembled from three molecular building blocks, possess incredible stability in various physiological conditions, reversible size-controllability and dynamic disassembly that were exploited for various in vitro and in vivo applications. An advantage of using the supramolecular approach is that it enables the convenient incorporation of functional ligands onto SNP surface that confers functionality ( e.g., targeting, cell penetration) to SNPs. We utilized SNPs for molecular imaging such as magnetic resonance imaging (MRI) and positron emission tomography (PET) by introducing reporter systems (i.e., radio-isotopes, MR contrast agents, and fluorophores) into SNPs. On the other hand, the incorporation of various payloads, including drugs, genes and proteins, into SNPs showed improved delivery performance and enhanced therapeutic efficacy for these therapeutic agents. Leveraging the powers of (i) a combinatorial synthetic approach based on supramolecular assembly and (ii) a digital microreactor, a rapid developmental pathway was developed that is capable of screening SNP candidates for the ideal structural and functional properties that deliver optimal performance. Moreover, SNP-based theranostic delivery systems that combine reporter systems and therapeutic payloads into a

  15. Magnetism: a supramolecular function

    Energy Technology Data Exchange (ETDEWEB)

    Decurtins, S.; Pellaux, R.; Schmalle, H.W. [Zurich Univ., Inst. fuer Anorganische Chemie, Zurich (Switzerland)

    1996-11-01

    The field of molecule-based magnetism has developed tremendously in the last few years. Two different extended molecular - hence supramolecular -systems are presented. The Prussian-blue analogues show some of the highest magnetic ordering temperature of any class of molecular magnets, T{sub c} = 315 K, whereas the class of transition-metal oxalate-bridged compounds exhibits a diversity of magnetic phenomena. Especially for the latter compounds, the elastic neutron scattering technique has successfully been proven to trace the magnetic structure of these supramolecular and chiral compounds. (author) 18 figs., 25 refs.

  16. Supramolecular interactions in the solid state

    Directory of Open Access Journals (Sweden)

    Giuseppe Resnati

    2015-11-01

    Full Text Available In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas of contemporary research involving supramolecular interactions in the solid state. The topics covered are: (1 an overview and historical review of halogen bonding; (2 exploring non-ambient conditions to investigate intermolecular interactions in crystals; (3 the role of intermolecular interactions in morphotropy, being the link between isostructurality and polymorphism; (4 strategic realisation of kinetic coordination polymers by exploiting multi-interactive linker molecules. The discussion touches upon many of the prerequisites for controlled preparation and characterization of crystalline materials.

  17. Supramolecular interactions in the solid state.

    Science.gov (United States)

    Resnati, Giuseppe; Boldyreva, Elena; Bombicz, Petra; Kawano, Masaki

    2015-11-01

    In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas of contemporary research involving supramolecular interactions in the solid state. The topics covered are: (1) an overview and historical review of halogen bonding; (2) exploring non-ambient conditions to investigate intermolecular interactions in crystals; (3) the role of intermolecular interactions in morphotropy, being the link between isostructurality and polymorphism; (4) strategic realisation of kinetic coordination polymers by exploiting multi-interactive linker molecules. The discussion touches upon many of the prerequisites for controlled preparation and characterization of crystalline materials.

  18. Porphyrinic supramolecular daisy chains incorporating pillar[5]arene-viologen host-guest interactions

    KAUST Repository

    Fathalla, Maher

    2015-05-18

    A porphyrin functionalised with pillar[5]arene and a viologen at its 5- and 15-meso positions assembles in a head-to-tail manner, producing linear supramolecular daisy chains in dichloromethane. At high concentrations, it forms an organogel which has been investigated by electron microscopy and rheological measurements, paving the way for the preparation of other functional supramolecular assemblies which harness viologen"⊂" pillararene host-guest interactions.

  19. Glassy carbon electrodes modified with supramolecular assemblies generated by π-stacking of Cobalt (II) octaethylporphyrins. A 4 electrons-dioxygen reduction reaction occurring at positive potentials

    International Nuclear Information System (INIS)

    A new method of modifying previously oxidized glassy carbon electrode (GCE) using commercial cobalt (II) porphyrin is proposed. This novel assembly presents a significant improvement in terms of electroactivity towards the oxygen reduction reaction (ORR), as compared to other reported systems. The device reduces molecular oxygen at positive potentials involving 4 electrons, as corroborated by kinetic studies. In addition, a 46 mV per decade Tafel slope was obtained, evidencing that the ORR mechanism would involve a chemical step following the first electron transfer, or, the rate determining step would be the transfer of a second electron. Concomitant to this, studies with different metalloporphirins were accomplished in order to compare the central metal ion effect. Morphological studies conducted using Atomic Force Microscopy (AFM) consistent with the proposed modification based on the structural changes found on the GCE surface, as well as to the obtained differences of roughness parameters (Rq values). Finally, it was demonstrated that this new system is better, in terms of electroactivity, than previously reported arrays

  20. Supramolecular Chemistry in Water

    NARCIS (Netherlands)

    Oshovsky, Gennady V.; Reinhoudt, David N.; Verboom, Willem

    2007-01-01

    Supramolecular chemistry in water is a constantly growing research area because noncovalent interactions in aqueous media are important for obtaining a better understanding and control of the major processes in nature. This Review offers an overview of recent advances in the area of water-soluble sy

  1. Supramolecular bacterial systems

    NARCIS (Netherlands)

    Sankaran, Shrikrishnan

    2015-01-01

    For nearly over a decade, a wide variety of dynamic and responsive supramolecular architectures have been investigated and developed to address biological systems. Since the non-covalent interactions between individual molecular components in such architectures are similar to the interactions found

  2. From structure to function via complex supramolecular dendrimer systems.

    Science.gov (United States)

    Sun, Hao-Jan; Zhang, Shaodong; Percec, Virgil

    2015-06-21

    This tutorial review summarizes strategies elaborated for the discovery and prediction of programmed primary structures derived from quasi-equivalent constitutional isomeric libraries of self-assembling dendrons, dendrimers and dendronized polymers. These libraries demonstrate an 82% predictability, defined as the percentage of similar primary structures resulting in at least one conserved supramolecular shape with internal order. A combination of structural and retrostructural analysis that employs methodologies transplanted from structural biology, adapted to giant supramolecular assemblies was used for this process. A periodic table database of programmed primary structures was elaborated and used to facilitate the emergence of a diversity of functions in complex dendrimer systems via first principles. Assemblies generated by supramolecular and covalent polymer backbones were critically compared. Although by definition complex functional systems cannot be designed, this tutorial hints to a methodology based on database analysis principles to facilitate design principles that may help to mediate an accelerated emergence of chemical, physical and most probably also societal, political and economic complex systems on a shorter time scale and lower cost than by the current methods. This tutorial review is limited to the simplest, synthetically most accessible self-assembling minidendrons, minidendrimers and polymers dendronized with minidendrons that are best analyzed and elucidated at molecular, supramolecular and theoretical levels, and most used in other laboratories. These structures are all interrelated, and their principles expand in a simple way to their higher generations. PMID:25325787

  3. Chemical Equilibrium in Supramolecular Systems as Studied by NMR Spectrometry

    Science.gov (United States)

    Gonzalez-Gaitano, Gustavo; Tardajos, Gloria

    2004-01-01

    Undergraduate students are required to study the chemical balance in supramolecular assemblies constituting two or more interacting species, by using proton NMR spectrometry. A good knowledge of physical chemistry, fundamentals of chemical balance, and NMR are pre-requisites for conducting this study.

  4. Supramolecular Filaments Containing a Fixed 41% Paclitaxel Loading

    OpenAIRE

    Lin, Ran; Cheetham, Andrew G.; Zhang, Pengcheng; Lin, Yi-An; Cui, Honggang

    2013-01-01

    We report here the self-assembly of a rationally designed paclitaxel drug amphiphile into well-defined supramolecular filaments that possess a fixed 41% paclitaxel loading. These filaments can exert effective cytotoxicity against a number of cell lines comparable to that of free paclitaxel.

  5. Molecular basis and consequences of a deletion in the amelogenin gene, analyzed by capture PCR

    Energy Technology Data Exchange (ETDEWEB)

    Lagerstroem-Fermer, M.; Pettersson, U.; Landegren, U. (Univ. of Uppsala (Sweden))

    1993-07-01

    A mutation that disrupts the gene for one of the major proteins in tooth enamel has been investigated. The mutation is located in the amelogenin gene and causes X-linked amelogenesis imperfecta, characterized by defective mineralization of tooth enamel. The authors have isolated the breakpoints of a 5-kb deletion in the amelogenin gene on the basis of nucleotide sequence information located upstream of the lesion, using a technique termed capture PCR. The deletion removes five of the seven exons, spanning from the second intron to the last exon. Only the first two codons for the mature protein remain, consistent with the relatively severe phenotype of affected individuals in the present family. The mutation appears to have arisen as an illegitimate recombination event since of 11 nucleotide positions immediately surrounding the two breakpoints, 9 are identical. 17 refs., 3 figs., 1 tab.

  6. Expression of Recombinant Human Amelogenin in Iranian Lizard Leishmania and Its Biological Function Assay

    Directory of Open Access Journals (Sweden)

    Zahra YADEGARI

    2015-10-01

    Full Text Available Background: Amelogenins are the major components of enamel matrix proteins. Enamel matrix derivatives (EMD can be used in periodontal diseases to regenerate periodontal tissues. The main aim of this study was to evaluate ex-pression of full-length functional recombinant human amelogenin (rhAm in Iranian lizard Leishmania (I.L.L. as an alternative eukaryotic expression system.Methods: Human cDNA encoding a 175-amino acid amelogenin expression cassette was sub cloned into a pLEXSY vector. The construct was transferred into Leishmania cells by electroporation. The protein production was surveyed in the transcription and the translation levels. The expressed protein was purified and some of its biological properties were investigated in comparison to EMD and negative control.Results: Expression of rhAm was confirmed by RT-PCR and western blot test in Leishmania cells. Purified rhAm sig-nificantly inhibited the formation of tartrate-resistant acid phosphatase positive (TRAP+ multinuclear cells in calcitriol stimulated mouse marrow cultures. Moreover, it significantly promoted proliferation and DNA synthesis in L929 mouse fibroblast cells.Conclusion: Functional rhAm was successfully expressed in I.L.L. Easy handling and post translation modification were the main advantages of this expression system. It is suggested to investigate molecular properties of this rhAm in the future.

  7. TPPS和Gemini表面活性剂的复合膜及其手性的研究%Supramolecular Assembly and Chirality of a Complex Film between Achiral TPPS and a Gemini Surfactant at the Air/water Interface

    Institute of Scientific and Technical Information of China (English)

    张莉; 王金本; 刘鸣华

    2004-01-01

    研究了一种新的gemini表面活性剂(C 12H24-α,ω-(C12H25N+(CH3)2Br-)2,(简写为C12-C12-C12)和TPPS在气液界面上形成的复合膜及其手性.实验发现,单独C12-C12-C12不能在纯水表面形成稳定的单分子膜,但当亚相中存在TPPS时,可形成稳定的单分子膜.通过水平提拉法将复合膜转移到固体基板上,发现在适当的pH值条件下,TPPS可在复合膜中形成J-聚集体,并且发现,尽管Gemini表面活性剂和TPPS都是非手性的,TPPS的J-聚集体表现出强烈的Cotton效应.另外,gemini表面活性剂的两个正电荷中心对TPPS的J-聚集体的手性并不能表现出协同效应.%Supramolecular assembly and chirality between a novel gemini surfactant (C12H24-α, ω-(C12H25N + (CH3)2Br-)2,(abbreviated as C12-C12-C12) and TPPS (tetrakis(4-sulfonatophenyl) porphine) at the air/water interface were investigated. It was found that although the gemini surfactant itself could not form a stable monolayer at the air/water interface, when there existed TPPS in the subphase, a stable complex monolayer could be formed. The complex monolayer could be transferred onto solid substrate by a horizontal lifting method. At a certain pH value of the subphase, TPPS could form a J-aggregate. It was further found that the J-aggregate of TPPS showed a strong split Cotton effect in the transferred film although both the gemini surfactant and TPPS are achiral. Further investigation through AFM measurements revealed that the nanothread formed in the transferred film was responsible for the chirality of the multilayer film. In addition, the two positive charge center of the gemini surfactant did not necessarily play the cooperative role in inducing the chirality of TPPS J-aggregate.

  8. Protein Camouflage: Supramolecular Anion Recognition by Ubiquitin.

    Science.gov (United States)

    Mallon, Madeleine; Dutt, Som; Schrader, Thomas; Crowley, Peter B

    2016-04-15

    Progress in the field of bio-supramolecular chemistry, the bottom-up assembly of protein-ligand systems, relies on a detailed knowledge of molecular recognition. To address this issue, we have characterised complex formation between human ubiquitin (HUb) and four supramolecular anions. The ligands were: pyrenetetrasulfonic acid (4PSA), p-sulfonato-calix[4]arene (SCLX4), bisphosphate tweezers (CLR01) and meso-tetrakis (4-sulfonatophenyl)porphyrin (TPPS), which vary in net charge, size, shape and hydrophobicity. All four ligands induced significant changes in the HSQC spectrum of HUb. Chemical shift perturbations and line-broadening effects were used to identify binding sites and to quantify affinities. Supporting data were obtained from docking simulations. It was found that these weakly interacting ligands bind to extensive surface patches on HUb. A comparison of the data suggests some general indicators for the protein-binding specificity of supramolecular anions. Differences in binding were observed between the cavity-containing and planar ligands. The former had a preference for the arginine-rich, flexible C terminus of HUb. PMID:26818656

  9. Supramolecular chemistry-general principles and selected examples from anion recognition and metallosupramolecular chemistry.

    Science.gov (United States)

    Albrecht, Markus

    2007-12-01

    This review gives an introduction into supramolecular chemistry describing in the first part general principles, focusing on terms like noncovalent interaction, molecular recognition, self-assembly, and supramolecular function. In the second part those will be illustrated by simple examples from our laboratories. Supramolecular chemistry is the science that bridges the gap between the world of molecules and nanotechnology. In supramolecular chemistry noncovalent interactions occur between molecular building blocks, which by molecular recognition and self-assembly form (functional) supramolecular entities. It is also termed the "chemistry of the noncovalent bond." Molecular recognition is based on geometrical complementarity based on the "key-and-lock" principle with nonshape-dependent effects, e.g., solvatization, being also highly influential. Self-assembly leads to the formation of well-defined aggregates. Hereby the overall structure of the target ensemble is controlled by the symmetry features of the certain building blocks. Finally, the aggregates can possess special properties or supramolecular functions, which are only found in the ensemble but not in the participating molecules. This review gives an introduction on supramolecular chemistry and illustrates the fundamental principles by recent examples from our group.

  10. Constructing supramolecular nanostructure by hydrogen-bonding

    Institute of Scientific and Technical Information of China (English)

    LI YiBao; ZENG QingDao; WANG ZhiHui; QI GuiCun; GUAN Li; FAN XiaoLin; WANG Chen

    2008-01-01

    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 nanostrueture were suc-cessfully fabricated. The result illustrates that it is possible to construct and control supramolecular nanostructure by intermolecular hydrogen-bonding.

  11. Supramolecular chemistry of cucurbiturils

    International Nuclear Information System (INIS)

    The main principles of the design of supramolecular compounds starting from organic macrocyclic cavitands, viz., cucurbit[n]urils [C6H6N4O2]n (n=5-10), are considered. The presence of the hydrophobic inner cavity along with polar carbonyl groups forming the cucurbituril portals are responsible for high specificity of the formation of host-guest complexes. The unique ability of cucurbiturils to act as synthetic molecular containers is discussed. In these containers, bimolecular reactions between specially selected guests proceed with high regio- and stereoselectivity. The review surveys new data on the directed construction of supramolecular organic-inorganic compounds through the formation of an extensive network of hydrogen bonds between the portal oxygen atoms of cucurbiturils and water molecules of metal aqua complexes. The bibliography includes 108 references.

  12. A supramolecular tubular nanoreactor.

    Science.gov (United States)

    Li, Zhi-Qiang; Zhang, Ying-Ming; Chen, Yong; Liu, Yu

    2014-07-01

    The extremely strong noncovalent complexation between the rigid host of phthalocyanine-bridged β-cyclodextrins and the amphiphilic guest carboxylated porphyrin is employed to construct a hollow tubular structure as a supramolecular nanoreactor. A representative coupling reaction occurs in the hydrophobic interlayers of the tubular walls in pure water at room temperature, leading to an enhancement of ten times higher reaction rate without any adverse effect on catalytic activity and conversion. PMID:24890802

  13. Supramolecular chemistry in silico

    OpenAIRE

    Sheehan, Rosemary; Cragg, Peter J.

    2008-01-01

    Abstract Computational protocols capable of modelling supramolecular complexes have been evaluated. The complexation of cations by crown ethers and quaternary ammonium ions by an oxacalix[3]arene are presented as examples. In the latter case reliable qualitative results were obtained using the semi-empirical PM3 method where guest LUMO and electrostatic potential energies have been shown to correlate with experimental binding data. The optimal method for more accurate results combi...

  14. Supramolecular bacterial systems

    OpenAIRE

    Sankaran, Shrikrishnan

    2015-01-01

    For nearly over a decade, a wide variety of dynamic and responsive supramolecular architectures have been investigated and developed to address biological systems. Since the non-covalent interactions between individual molecular components in such architectures are similar to the interactions found in living systems, it was possible to integrate chemically-synthesized and naturally-occurring components to create platforms with interesting bioactive properties. Bacterial cells and recombinant ...

  15. Flourishing Development in Supramolecular Chemistry%蓬勃发展的超分子化学

    Institute of Scientific and Technical Information of China (English)

    张来新; 朱海云

    2014-01-01

    This paper briefly introduces the concepts and applications of supramolecular chemistry.Emphases are put on three parts:①selective anion recognition of supramolecular self-assembly;②synthesis and applications of supramolecular metal complexes;③synthesis and applications of supramolecular receptor in medicine.Future de-velopments of supramolecular chemistry are prospected in the end.%本文简要介绍了超分子化学的概念及应用,详细综述了:①超分子自组装对阴离子的选择性识别作用;②超分子金属配合物的合成及应用;③医用超分子受体的合成及应用。并对超分子化学的发展进行了展望。

  16. Anion induced modulation of self-assembly and optical properties in urea end-capped oligo(p-phenylenevinylene)s.

    Science.gov (United States)

    Varghese, Reji; George, Subi J; Ajayaghosh, Ayyappanpillai

    2005-02-01

    The non-emissive supramolecular assembly of urea end-capped oligo(p-phenylenevinylene) flourophores turned strongly emissive in the presence of tetrabutylammonium flouride which has implications in the anion controlled design of supramolecular architectures with tunable emission properties.

  17. Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

    Science.gov (United States)

    Lehn, Jean-Marie

    2012-01-01

    Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

  18. Toward Modular Analysis of Supramolecular Protein Assemblies.

    Science.gov (United States)

    Kim, Jaehoon; Kim, Jin-Gyun; Yun, Giseok; Lee, Phill-Seung; Kim, Do-Nyun

    2015-09-01

    Despite recent advances in molecular simulation technologies, analysis of high-molecular-weight structures is still challenging. Here, we propose an automated model reduction procedure aiming to enable modular analysis of these structures. It employs a component mode synthesis for the reduction of finite element protein models. Reduced models may consist of real biological subunits or artificial partitions whose dynamics is described using the degrees of freedom at the substructural interfaces and a small set of dominant vibrational modes only. Notably, the proper number of dominant modes is automatically determined using a novel estimator for eigenvalue errors without calculating the reference eigensolutions of the full model. The performance of the proposed approach is thoroughly investigated by analyzing 50 representative structures including a crystal structure of GroEL and an electron density map of a ribosome. PMID:26575921

  19. Self-assembly behaviour of conjugated terthiophene surfactants in water

    NARCIS (Netherlands)

    van Rijn, Patrick; Janeliunas, Dainius; Brizard, Aurelie M.; Stuart, Marc C. A.; Koper, Ger J. M.; Eelkema, Rienk; van Esch, Jan H.

    2011-01-01

    Conjugated self-assembled systems in water are of great interest because of their potential application in biocompatible supramolecular electronics, but so far their supramolecular chemistry remains almost unexplored. Here we present amphiphilic terthiophenes as a general self-assembling platform fo

  20. Molecular self-assembly advances and applications

    CERN Document Server

    Dequan, Alex Li

    2012-01-01

    In the past several decades, molecular self-assembly has emerged as one of the main themes in chemistry, biology, and materials science. This book compiles and details cutting-edge research in molecular assemblies ranging from self-organized peptide nanostructures and DNA-chromophore foldamers to supramolecular systems and metal-directed assemblies, even to nanocrystal superparticles and self-assembled microdevices

  1. Supramolecular polymer transformation: a kinetic study.

    Science.gov (United States)

    Baram, Jonathan; Weissman, Haim; Rybtchinski, Boris

    2014-10-16

    Investigation of supramolecular kinetics is essential for elucidating self-assembly mechanisms. Recently, we reported on a noncovalent system involving a bolaamphiphilic perylene diimide dimer that is kinetically trapped in water but can rearrange into a different, more ordered assembly in water/THF mixtures ( Angew. Chem. Int. Ed. 2014 , 53 , 4123 ). Here we present a kinetic mechanistic study of this process by employing UV-vis spectroscopy. The transformation exhibits a rapid decrease in the red-shifted absorption band, which is monitored in order to track the kinetics at different temperatures (15-50 °C) and concentrations. Fitting the data with the 1D KJMA (Kolmogorov-Johnson-Mehl-Avrami) model affords the activation parameters. The latter as well as seeding experiments indicates that the transformation occurs without the detachment of covalent units, and that hydration dynamics plays a significant role in nucleation, with entropic factors being dominant. Switching off the transformation, and the formation of off-pathway intermediates were observed upon heating to temperatures above 55 °C. These insights into kinetically controlled supramolecular polymer transformations provide mechanistic information that is needed for a fundamental understanding of noncovalent processes, and the rational design of noncovalent materials. PMID:25238603

  2. Freestanding 3D supramolecular particle bridges: fabrication and mechanical behavior.

    Science.gov (United States)

    Ling, Xing Yi; Phang, In Yee; Schönherr, Holger; Reinhoudt, David N; Vancso, G Julius; Huskens, Jurriaan

    2009-06-01

    Freestanding particle bridges with controlled composition and macroscopic robustness are demonstrated by the use of supramolecular nanoparticle assembly. Self-assembly of nanoparticles, templating, and supramolecular glue infiltration are combined to form stable and ordered three-dimensional polystyrene particle composites on a polydimethylsiloxane stamp. Freestanding hybrid polystyrene nanoparticle bridges are obtained by transfer printing of the hybrid structures onto topographically patterned substrates via host-guest interactions. The mechanical robustness and rigidity of the particle bridges can be controlled by manipulating the layer-by-layer cycles of supramolecular glues of gold nanoparticles and dendrimers. Atomic force microscopy-based microbending results, in particular the location and force-dependent deflection behavior, confirm that the particle bridge fulfills the classical supported-beam characteristics. As estimated from classical beam theory, the bending moduli of the particle bridges vary between 0.8 and 1.1 GPa, depending on the degree of filling by the supramolecular glues. Failure analysis on the particle structure indicates linear elastic behavior and a plastic deformation upon failure. PMID:19373830

  3. Cementomimetics-constructing a cementum-like biomineralized microlayer via amelogenin-derived peptides.

    Science.gov (United States)

    Gungormus, Mustafa; Oren, Ersin E; Horst, Jeremy A; Fong, Hanson; Hnilova, Marketa; Somerman, Martha J; Snead, Malcolm L; Samudrala, Ram; Tamerler, Candan; Sarikaya, Mehmet

    2012-06-01

    Cementum is the outer-, mineralized-tissue covering the tooth root and an essential part of the system of periodontal tissue that anchors the tooth to the bone. Periodontal disease results from the destructive behavior of the host elicited by an infectious biofilm adhering to the tooth root and left untreated, may lead to tooth loss. We describe a novel protocol for identifying peptide sequences from native proteins with the potential to repair damaged dental tissues by controlling hydroxyapatite biomineralization. Using amelogenin as a case study and a bioinformatics scoring matrix, we identified regions within amelogenin that are shared with a set of hydroxyapatite-binding peptides (HABPs) previously selected by phage display. One 22-amino acid long peptide regions referred to as amelogenin-derived peptide 5 (ADP5) was shown to facilitate cell-free formation of a cementum-like hydroxyapatite mineral layer on demineralized human root dentin that, in turn, supported attachment of periodontal ligament cells in vitro. Our findings have several implications in peptide-assisted mineral formation that mimic biomineralization. By further elaborating the mechanism for protein control over the biomineral formed, we afford new insights into the evolution of protein-mineral interactions. By exploiting small peptide domains of native proteins, our understanding of structure-function relationships of biomineralizing proteins can be extended and these peptides can be utilized to engineer mineral formation. Finally, the cementomimetic layer formed by ADP5 has the potential clinical application to repair diseased root surfaces so as to promote the regeneration of periodontal tissues and thereby reduce the morbidity associated with tooth loss.

  4. Controlled Osteogenic Differentiation of Mouse Mesenchymal Stem Cells by Tetracycline-Controlled Transcriptional Activation of Amelogenin.

    Science.gov (United States)

    Wang, Fangfang; Okawa, Hiroko; Kamano, Yuya; Niibe, Kunimichi; Kayashima, Hiroki; Osathanon, Thanaphum; Pavasant, Prasit; Saeki, Makio; Yatani, Hirofumi; Egusa, Hiroshi

    2015-01-01

    Regenerative dental therapies for bone tissues rely on efficient targeting of endogenous and transplanted mesenchymal stem cells (MSCs) to guide bone formation. Amelogenin is the primary component of Emdogain, which is used to regenerate periodontal defects; however, the mechanisms underlying the therapeutic effects on alveolar bone remain unclear. The tetracycline (Tet)-dependent transcriptional regulatory system is a good candidate to investigate distinct roles of genes of interest during stem cell differentiation. Here, we investigated amelogenin-dependent regulation of osteogenesis in MSCs by establishing a Tet-controlled transcriptional activation system. Clonal mouse bone marrow-derived MSCs were lentivirally transduced with the Tet repressor (TetR) expression vector followed by drug selection to obtain MSCs constitutively expressing TetR (MSCs-TetR). Expression vectors that contained the Tet operator and amelogenin-coding (Amelx) cDNA fragments were constructed using the Gateway system and lentivirally introduced into MSCs-TetR to generate a Tet regulation system in MSCs (MSCs-TetR/Amelx). MSCs-TetR/Amelx significantly overexpressed the Amelx gene and protein in the presence of the tetracycline derivative doxycycline. Concomitant expression of osterix, bone sialoprotein (BSP), osteopontin, and osteocalcin was modulated by addition or removal of doxycycline under osteogenic guidance. During osteogenic induction, MSCs-TetR/Amelx treated with doxycycline showed significantly increased gene expression of osterix, type I collagen, BSP, and osteocalcin in addition to increased alkaline phosphatase activity and mineralized nodule formation. Enhanced extracellular matrix calcification was observed when forced Amelx expression commenced at the early stage but not at the intermediate or late stages of osteogenesis. These results suggest that a Tet-controlled Amelx gene regulation system for mouse MSCs was successfully established, in which transcriptional activation

  5. Controlled Osteogenic Differentiation of Mouse Mesenchymal Stem Cells by Tetracycline-Controlled Transcriptional Activation of Amelogenin.

    Directory of Open Access Journals (Sweden)

    Fangfang Wang

    Full Text Available Regenerative dental therapies for bone tissues rely on efficient targeting of endogenous and transplanted mesenchymal stem cells (MSCs to guide bone formation. Amelogenin is the primary component of Emdogain, which is used to regenerate periodontal defects; however, the mechanisms underlying the therapeutic effects on alveolar bone remain unclear. The tetracycline (Tet-dependent transcriptional regulatory system is a good candidate to investigate distinct roles of genes of interest during stem cell differentiation. Here, we investigated amelogenin-dependent regulation of osteogenesis in MSCs by establishing a Tet-controlled transcriptional activation system. Clonal mouse bone marrow-derived MSCs were lentivirally transduced with the Tet repressor (TetR expression vector followed by drug selection to obtain MSCs constitutively expressing TetR (MSCs-TetR. Expression vectors that contained the Tet operator and amelogenin-coding (Amelx cDNA fragments were constructed using the Gateway system and lentivirally introduced into MSCs-TetR to generate a Tet regulation system in MSCs (MSCs-TetR/Amelx. MSCs-TetR/Amelx significantly overexpressed the Amelx gene and protein in the presence of the tetracycline derivative doxycycline. Concomitant expression of osterix, bone sialoprotein (BSP, osteopontin, and osteocalcin was modulated by addition or removal of doxycycline under osteogenic guidance. During osteogenic induction, MSCs-TetR/Amelx treated with doxycycline showed significantly increased gene expression of osterix, type I collagen, BSP, and osteocalcin in addition to increased alkaline phosphatase activity and mineralized nodule formation. Enhanced extracellular matrix calcification was observed when forced Amelx expression commenced at the early stage but not at the intermediate or late stages of osteogenesis. These results suggest that a Tet-controlled Amelx gene regulation system for mouse MSCs was successfully established, in which transcriptional

  6. Versatile types of polysaccharide-based supramolecular polycation/pDNA nanoplexes for gene delivery

    Science.gov (United States)

    Hu, Yang; Zhao, Nana; Yu, Bingran; Liu, Fusheng; Xu, Fu-Jian

    2014-06-01

    Different polysaccharide-based supramolecular polycations were readily synthesized by assembling multiple β-cyclodextrin-cored star polycations with an adamantane-functionalized dextran via host-guest interaction in the absence or presence of bioreducible linkages. Compared with nanoplexes of the starting star polycation and pDNA, the supramolecular polycation/pDNA nanoplexes exhibited similarly low cytotoxicity, improved cellular internalization and significantly higher gene transfection efficiencies. The incorporation of disulfide linkages imparted the supramolecular polycation/pDNA nanoplexes with the advantage of intracellular bioreducibility, resulting in better gene delivery properties. In addition, the antitumor properties of supramolecular polycation/pDNA nanoplexes were also investigated using a suicide gene therapy system. The present study demonstrates that the proper assembly of cyclodextrin-cored polycations with adamantane-functionalized polysaccharides is an effective strategy for the production of new nanoplex delivery systems.Different polysaccharide-based supramolecular polycations were readily synthesized by assembling multiple β-cyclodextrin-cored star polycations with an adamantane-functionalized dextran via host-guest interaction in the absence or presence of bioreducible linkages. Compared with nanoplexes of the starting star polycation and pDNA, the supramolecular polycation/pDNA nanoplexes exhibited similarly low cytotoxicity, improved cellular internalization and significantly higher gene transfection efficiencies. The incorporation of disulfide linkages imparted the supramolecular polycation/pDNA nanoplexes with the advantage of intracellular bioreducibility, resulting in better gene delivery properties. In addition, the antitumor properties of supramolecular polycation/pDNA nanoplexes were also investigated using a suicide gene therapy system. The present study demonstrates that the proper assembly of cyclodextrin-cored polycations

  7. Fragmentation and Coagulation in Supramolecular (Co)polymerization Kinetics.

    Science.gov (United States)

    Markvoort, Albert J; Eikelder, Huub M M Ten; Hilbers, Peter A J; de Greef, Tom F A

    2016-04-27

    The self-assembly of molecular building blocks into one-dimensional supramolecular architectures has opened up new frontiers in materials science. Due to the noncovalent interactions between the monomeric units, these architectures are intrinsically dynamic, and understanding their kinetic driving forces is key to rationally programming their morphology and function. To understand the self-assembly dynamics of supramolecular polymerizations (SP), kinetic models based on aggregate growth by sequential monomer association and dissociation have been analyzed. However, fragmentation and coagulation events can also play a role, as evident from studies on peptide self-assembly and the fact that aggregations can be sensitive to mechanical agitations. Here, we analyze how fragmentation and coagulation events influence SP kinetics by theoretical analysis of self-assembling systems of increasing complexity. Our analysis starts with single-component systems in which aggregates are able to grow via an isodesmic or cooperative nucleation-elongation mechanism. Subsequently, equilibration dynamics in cooperative two-component supramolecular copolymerizations are investigated. In the final part, we reveal how aggregate growth in the presence of competing, kinetically controlled pathways is influenced by fragmentation and coagulation reactions and reveal how seed-induced growth can give rise to block copolymers. Our analysis shows how fragmentation and coagulation reactions are able to modulate SP kinetics in ways that are highly system dependent. PMID:27163054

  8. Supramolecular spin valves.

    Science.gov (United States)

    Urdampilleta, M; Klyatskaya, S; Cleuziou, J-P; Ruben, M; Wernsdorfer, W

    2011-07-01

    Magnetic molecules are potential building blocks for the design of spintronic devices. Moreover, molecular materials enable the combination of bottom-up processing techniques, for example with conventional top-down nanofabrication. The development of solid-state spintronic devices based on the giant magnetoresistance, tunnel magnetoresistance and spin-valve effects has revolutionized magnetic memory applications. Recently, a significant improvement of the spin-relaxation time has been observed in organic semiconductor tunnel junctions, single non-magnetic molecules coupled to magnetic electrodes have shown giant magnetoresistance and hybrid devices exploiting the quantum tunnelling properties of single-molecule magnets have been proposed. Herein, we present an original spin-valve device in which a non-magnetic molecular quantum dot, made of a single-walled carbon nanotube contacted with non-magnetic electrodes, is laterally coupled through supramolecular interactions to TbPc(2) single-molecule magnets (Pc=phthalocyanine). Their localized magnetic moments lead to a magnetic field dependence of the electrical transport through the single-walled carbon nanotube, resulting in magnetoresistance ratios up to 300% at temperatures less than 1 K. We thus demonstrate the functionality of a supramolecular spin valve without magnetic leads. Our results open up prospects of new spintronic devices with quantum properties. PMID:21685902

  9. Ostwald's rule of stages governs structural transitions and morphology of dipeptide supramolecular polymers.

    Science.gov (United States)

    Levin, Aviad; Mason, Thomas O; Adler-Abramovich, Lihi; Buell, Alexander K; Meisl, George; Galvagnion, Celine; Bram, Yaron; Stratford, Samuel A; Dobson, Christopher M; Knowles, Tuomas P J; Gazit, Ehud

    2014-01-01

    The self-assembly of molecular building blocks into nano- and micro-scale supramolecular architectures has opened up new frontiers in polymer science. Such supramolecular species not only possess a rich set of dynamic features as a consequence of the non-covalent nature of their core interactions, but also afford unique structural characteristics. Although much is now known about the manner in which such structures adopt their morphologies and size distributions in response to external stimuli, the kinetic and thermodynamic driving forces that lead to their transformation from soluble monomeric species into ordered supramolecular entities have remained elusive. Here we focus on Boc-diphenylalanine, an archetypical example of a peptide with a high propensity towards supramolecular self-organization, and describe the pathway through which it forms a range of nano-assemblies with different structural characteristics. Our results reveal that the nucleation process is multi-step in nature and proceeds by Ostwald's step rule through which coalescence of soluble monomers leads to the formation of nanospheres, which then undergo ripening and structural conversions to form the final supramolecular assemblies. We characterize the structures and thermodynamics of the different phases involved in this process and reveal the intricate nature of the transitions that can occur between discrete structural states of this class of supramolecular polymers. PMID:25391268

  10. Ostwald’s rule of stages governs structural transitions and morphology of dipeptide supramolecular polymers

    Science.gov (United States)

    Levin, Aviad; Mason, Thomas O.; Adler-Abramovich, Lihi; Buell, Alexander K.; Meisl, George; Galvagnion, Celine; Bram, Yaron; Stratford, Samuel A.; Dobson, Christopher M.; Knowles, Tuomas P. J.; Gazit, Ehud

    2014-11-01

    The self-assembly of molecular building blocks into nano- and micro-scale supramolecular architectures has opened up new frontiers in polymer science. Such supramolecular species not only possess a rich set of dynamic features as a consequence of the non-covalent nature of their core interactions, but also afford unique structural characteristics. Although much is now known about the manner in which such structures adopt their morphologies and size distributions in response to external stimuli, the kinetic and thermodynamic driving forces that lead to their transformation from soluble monomeric species into ordered supramolecular entities have remained elusive. Here we focus on Boc-diphenylalanine, an archetypical example of a peptide with a high propensity towards supramolecular self-organization, and describe the pathway through which it forms a range of nano-assemblies with different structural characteristics. Our results reveal that the nucleation process is multi-step in nature and proceeds by Ostwald’s step rule through which coalescence of soluble monomers leads to the formation of nanospheres, which then undergo ripening and structural conversions to form the final supramolecular assemblies. We characterize the structures and thermodynamics of the different phases involved in this process and reveal the intricate nature of the transitions that can occur between discrete structural states of this class of supramolecular polymers.

  11. Transfer-printing and host-guest properties of 3D supramolecular particle structures.

    Science.gov (United States)

    Ling, Xing Yi; Phang, In Yee; Reinhoudt, David N; Vancso, G Julius; Huskens, Jurriaan

    2009-04-01

    Mechanically robust and crystalline supramolecular particle structures have been constructed by decoupling nanoparticle assembly and supramolecular glue infiltration into a sequential process. First, beta-cyclodextrin (CD)-functionalized polystyrene particles (d approximately 500 nm) were assembled on a CD-functionalized surface via convective assembly to form highly ordered, but mechanically unstable, particle crystals. Subsequently, the crystals were infiltrated by a solution of adamantyl-functionalized dendrimers, functioning as a supramolecular glue to bind neighboring particles together and to couple the entire particle crystal to the CD surface, both in a noncovalent manner. The supramolecular particle crystals are highly robust, as witnessed by their ability to withstand agitation by ultrasonication. When assembled on a poly(dimethylsiloxane) (PDMS) stamp, the dendrimer-infiltrated particle crystals could be transfer-printed onto a CD-functionalized target surface. By variation of the geometry and size of the PDMS stamps, single particle lines, interconnected particle rings, and V-shaped particle assemblies were obtained. The particle structures served as 3D receptors for the binding of (multiple) complementary guest molecules, indicating that the supramolecular host functionalities of the particle crystals were retained throughout the fabrication process. PMID:20356024

  12. Prion-like nanofibrils of small molecules (PriSM): A new frontier at the intersection of supramolecular chemistry and cell biology

    OpenAIRE

    Zhou, Jie; Du, Xuewen; Xu, Bing

    2015-01-01

    Formed by non-covalent interactions and not defined at genetic level, the assemblies of small molecules in biology are complicated and less explored. A common morphology of the supramolecular assemblies of small molecules is nanofibrils, which coincidentally resembles the nanofibrils formed by proteins such as prions. So these supramolecular assemblies are termed as prion-like nanofibrils of small molecules (PriSM). Emerging evidence from several unrelated fields over the past decade implies ...

  13. Different effects of 25-kDa amelogenin on the proliferation, attachment and migration of various periodontal cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiting [Department of Periodontology, Ninth People' s Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, No. 639 Zhi Zao Ju Road, Shanghai 200011 (China); Shu, Rong, E-mail: shurong123@hotmail.com [Department of Periodontology, Ninth People' s Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, No. 639 Zhi Zao Ju Road, Shanghai 200011 (China); Liu, Dali; Jiang, Shaoyun [Department of Periodontology, Ninth People' s Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, No. 639 Zhi Zao Ju Road, Shanghai 200011 (China)

    2010-04-09

    Previous studies have assumed that amelogenin is responsible for the therapeutic effect of the enamel matrix derivative (EMD) in periodontal tissue healing and regeneration. However, it is difficult to confirm this hypothesis because both the EMD and the amelogenins are complex mixtures of multiple proteins. Further adding to the difficulties is the fact that periodontal tissue regeneration involves various types of cells and a sequence of associated cellular events including the attachment, migration and proliferation of various cells. In this study, we investigated the potential effect of a 25-kDa recombinant porcine amelogenin (rPAm) on primarily cultured periodontal ligament fibroblasts (PDLF), gingival fibroblasts (GF) and gingival epithelial cells (GEC). The cells were treated with 25-kDa recombinant porcine amelogenin at a concentration of 10 {mu}g/mL. We found that rPAm significantly promoted the proliferation and migration of PDLF, but not their adhesion. Similarly, the proliferation and adhesion of GF were significantly enhanced by treatment with rPAm, while migration was greatly inhibited. Interestingly, this recombinant protein inhibited the growth rate, cell adhesion and migration of GEC. These data suggest that rPAm may play an essential role in periodontal regeneration through the activation of periodontal fibroblasts and inhibition of the cellular behaviors of gingival epithelial cells.

  14. Different effects of 25-kDa amelogenin on the proliferation, attachment and migration of various periodontal cells

    International Nuclear Information System (INIS)

    Previous studies have assumed that amelogenin is responsible for the therapeutic effect of the enamel matrix derivative (EMD) in periodontal tissue healing and regeneration. However, it is difficult to confirm this hypothesis because both the EMD and the amelogenins are complex mixtures of multiple proteins. Further adding to the difficulties is the fact that periodontal tissue regeneration involves various types of cells and a sequence of associated cellular events including the attachment, migration and proliferation of various cells. In this study, we investigated the potential effect of a 25-kDa recombinant porcine amelogenin (rPAm) on primarily cultured periodontal ligament fibroblasts (PDLF), gingival fibroblasts (GF) and gingival epithelial cells (GEC). The cells were treated with 25-kDa recombinant porcine amelogenin at a concentration of 10 μg/mL. We found that rPAm significantly promoted the proliferation and migration of PDLF, but not their adhesion. Similarly, the proliferation and adhesion of GF were significantly enhanced by treatment with rPAm, while migration was greatly inhibited. Interestingly, this recombinant protein inhibited the growth rate, cell adhesion and migration of GEC. These data suggest that rPAm may play an essential role in periodontal regeneration through the activation of periodontal fibroblasts and inhibition of the cellular behaviors of gingival epithelial cells.

  15. Supramolecular Polymers in DNA Nanotechnology

    OpenAIRE

    Vyborna, Yuliia; Vybornyi, Mykhailo; Häner, Robert

    2016-01-01

    Creation of biocompatible functional materials is an important task in supramolecular chemistry. In this contribution, we report on noncovalent synthesis of DNA-grafted supramolecular polymers (SPs). DNA-grafted SPs enable programmed arrangement of oligonucleotides in a regular, tightly packed one-dimensional array. Further interactions of DNA-grafted SPs with complementary DNA strands leads to the formation of networks through highly cooperative G-C blunt-end stacking interactions. The struc...

  16. Supramolecular nanofibrils inhibit cancer progression in vitro and in vivo

    OpenAIRE

    Kuang, Yi; Du, Xuewen; Zhou, Jie; Xu, Bing

    2014-01-01

    The recent discovery of the inverse comorbidity between cancer and Alzheimer’s disease implies that one may use amyloids to inhibit tumors. During the conversion of a dipeptide segment (Phe-Phe) in β-amyloid into a supramolecular hydrogelator, we obtained a small molecule (1) that can self-assembly into nanofibrils via multiple intermolecular hydrogen bonding and aromatic-aromatic interactions. Interestingly, while the monomers of 1 are innocuous, the nanofibrils formed by 1 can selectively i...

  17. Supramolecular clippers for controlling photophysical processes through preorganized chromophores.

    Science.gov (United States)

    Kumar, Mohit; Ushie, Onumashi Afi; George, Subi J

    2014-04-22

    A novel supramolecular clipping design for influencing the photophysical properties of functional molecular assemblies, by the preorganization (clipping) of chromophores, is described. Several chromophores end functionalized with molecular recognition units were designed. These molecular recognition units serve as handles to appropriately position these systems upon noncovalent interactions with multivalent guest molecules (supramolecular clippers). Towards this goal, we have synthesized 1,5-dialkoxynaphthalene (DAN) and naphthalenediimide (NDI) functionalized with dipicolylethylenediamine (DPA) motifs. These molecules could preorganize upon noncovalent clipping with adenosine di- or triphosphates, which resulted in preassociated excimers and mixed (cofacial) charge-transfer (CT) assemblies. Chiral guest binding could also induce supramolecular chirality, not only into the individual chromophoric assembly but also into the heteromeric CT organization, as seen from the strong circular dichroism (CD) signal of the CT transition. The unique ability of this design to influence the intermolecular interactions by changing the binding strength of the clippers furthermore makes it very attractive for controlling the bimolecular photophysical processes. PMID:24623564

  18. Supramolecular cyclodextrin-based drug nanocarriers.

    Science.gov (United States)

    Simões, Susana M N; Rey-Rico, Ana; Concheiro, Angel; Alvarez-Lorenzo, Carmen

    2015-04-14

    Supramolecular systems formed by the binding of several cyclodextrins (CDs) to polymers or lipids, either via non-covalent or covalent links, open a wide range of possibilities for the delivery of active substances. CDs can perform as multifunctionalizable cores to which very diverse (macro)molecules and drugs can be conjugated. Grafting with amphiphilic molecules can lead to nanoassemblies exhibiting a variety of architectures. CDs can also polymerize with other CDs or can be used to functionalize preexisting polymers to form polymers/networks with enhanced capability to form inclusion complexes. Alternatively, CDs can be exploited as transient cross-linkers to form poly(pseudo)rotaxane-based networks or zipper-like assemblies. Combination of mutifunctionality and complexation ability of CDs has been shown to be useful to develop depot-like formulations and colloidal nanocarriers with improved performances regarding easiness of administration, protection of the encapsulated substances, control of the delivery rate, and cell interactions. The aim of this review is to provide an overall view of the diversity of designs of CD-based supramolecular nanosystems with a special focus on the advances materialized in the last five years, including clinical trials. PMID:25679097

  19. Supramolecular approach to new inkjet printing inks.

    Science.gov (United States)

    Hart, Lewis R; Harries, Josephine L; Greenland, Barnaby W; Colquhoun, Howard M; Hayes, Wayne

    2015-04-29

    Electronically complementary, low molecular weight polymers that self-assemble through tunable π-π stacking interactions to form extended supramolecular polymer networks have been developed for inkjet printing applications and successfully deposited using three different printing techniques. Sequential overprinting of the complementary components results in supramolecular network formation through complexation of π-electron rich pyrenyl or perylenyl chain-ends in one component with π-electron deficient naphthalene diimide residues in a chain-folding polyimide. The complementary π-π stacked polymer blends generate strongly colored materials as a result of charge-transfer absorption bands in the visible spectrum, potentially negating the need for pigments or dyes in the ink formulation. Indeed, the final color of the deposited material can be tailored by varying the end-groups of the π-electron rich polymer component. Piezoelectric printing techniques were employed in a proof of concept study to allow characterization of the materials deposited, and a thermal inkjet printer adapted with imaging software enabled in situ analysis of the ink drops as they formed and of their physical properties. Finally, continuous inkjet printing allowed greater volumes of material to be deposited, on a variety of different substrate surfaces, and demonstrated the utility and versatility of this novel type of ink for industrial applications.

  20. Supramolecular Drug Delivery Systems Based on Water-Soluble Pillar[n]arenes.

    Science.gov (United States)

    Wu, Xuan; Gao, Lei; Hu, Xiao-Yu; Wang, Leyong

    2016-06-01

    Supramolecular drug delivery systems (SDDSs), including various kinds of nanostructures that are assembled by reversible noncovalent interactions, have attracted considerable attention as ideal drug carriers owing to their fascinating ability to undergo dynamic switching of structure, morphology, and function in response to various external stimuli, which provides a flexible and robust platform for designing and developing functional and smart supramolecular nano-drug carriers. Pillar[n]arenes represent a new generation of macrocyclic hosts, which have unique structures and excellent properties in host-guest chemistry. This account describes recent progress in our group to develop pillararene-based stimuli-responsive supramolecular nanostructures constructed by reversible host-guest interactions for controllable anticancer drug delivery. The potential applications of these supramolecular drug carriers in cancer treatment and the fundamental questions facing SDDSs are also discussed.

  1. 蓬勃发展的超分子化学∗%Flourishing Development in Supramolecular Chemistry

    Institute of Scientific and Technical Information of China (English)

    张来新; 陈琦

    2015-01-01

    The generation,development,and applications of supramolecular chemistry were briefly introduced in this paper. Emphases were put on from three parts:① synthesis and applications of new supramolecular com-pounds;② constructions of supramolecular polymer self-assembly and their applications;③ preparation and me-dicinal use of new supramolecular compounds. Future developments of supramolecular chemistry were prospected in the end.%简要介绍了超分子化学的产生发展及应用。详细介绍了:①新型超分子化合物的合成及应用;②超分子聚合物自组装的构筑及应用;③新型超分子化合物的制备及药用。并对超分子化学的发展进行了展望。

  2. Supramolecular fabrication of multilevel graphene-based gas sensors with high NO2 sensibility

    Science.gov (United States)

    Chen, Zhuo; Umar, Ahmad; Wang, Shiwei; Wang, Yao; Tian, Tong; Shang, Ying; Fan, Yuzun; Qi, Qi; Xu, Dongmei; Jiang, Lei

    2015-05-01

    This study reports the supramolecular assembly of a silver nanoparticle-naphthalene-1-sulphonic acid-reduced graphene oxide composite (Ag-NA-rGO) and its utilization to fabricate a highly sensitive and selective gas sensor. The prepared supramolecular assembly acted not only as a non-covalent functionalization platform (π-π interaction) but was also an excellent scaffold to fabricate a highly sensitive and selective low concentration NO2 gas sensor. The prepared composites were characterized using several techniques, which revealed that the graphene sheets were dispersed as ultrathin monolayers with a uniform distribution of silver nanoparticles. The fabricated multilevel structure exhibited an excellent sensing performance, i.e. 2.8 times better, towards 10 ppm NO2 compared to the NA-rGO and rGO based sensors. Apart from its high sensitivity, superior reversibility and selectivity, the prepared supramolecular assembly exhibited an outstanding linear response over the large concentration range from 1 ppm to 10 ppm. The obtained results demonstrate that the prepared supramolecular assembly holds great potential in the fabrication of efficient and effective low-concentration NO2 gas sensors for practical applications.This study reports the supramolecular assembly of a silver nanoparticle-naphthalene-1-sulphonic acid-reduced graphene oxide composite (Ag-NA-rGO) and its utilization to fabricate a highly sensitive and selective gas sensor. The prepared supramolecular assembly acted not only as a non-covalent functionalization platform (π-π interaction) but was also an excellent scaffold to fabricate a highly sensitive and selective low concentration NO2 gas sensor. The prepared composites were characterized using several techniques, which revealed that the graphene sheets were dispersed as ultrathin monolayers with a uniform distribution of silver nanoparticles. The fabricated multilevel structure exhibited an excellent sensing performance, i.e. 2.8 times better

  3. Exploring the complexity of supramolecular interactions for patterning at the liquid-solid interface.

    Science.gov (United States)

    Mali, Kunal S; Adisoejoso, Jinne; Ghijsens, Elke; De Cat, Inge; De Feyter, Steven

    2012-08-21

    The use of self-assembly to fabricate surface-confined adsorbed layers (adlayers) from molecular components provides a simple means of producing complex functional surfaces. The molecular self-assembly process relies on supramolecular interactions sustained by noncovalent forces such as van der Waals, electrostatic, dipole-dipole, and hydrogen bonding interactions. Researchers have exploited these noncovalent bonding motifs to construct well-defined two-dimensional (2D) architectures at the liquid-solid interface. Despite myriad examples of 2D molecular assembly, most of these early findings were serendipitous because the intermolecular interactions involved in the process are often numerous, subtle, cooperative, and multifaceted. As a consequence, the ability to tailor supramolecular patterns has evolved slowly. Insight gained from various studies over the years has contributed significantly to the knowledge of supramolecular interactions, and the stage is now set to systematically engineer the 2D supramolecular networks in a "preprogrammed" fashion. The control over 2D self-assembly of molecules has many important implications. Through appropriate manipulation of supramolecular interactions, one can "encode" the information at the molecular level via structural features such as functional groups, substitution patterns, and chiral centers which could then be retrieved, transferred, or amplified at the supramolecular level through well-defined molecular recognition processes. This ability allows for precise control over the nanoscale structure and function of patterned surfaces. A clearer understanding and effective use of these interactions could lead to the development of functional surfaces with potential applications in molecular electronics, chiral separations, sensors based on host-guest systems, and thin film materials for lubrication. In this Account, we portray our various attempts to achieve rational design of self-assembled adlayers by exploiting the

  4. Electrochemical redox responsive polymeric micelles formed from amphiphilic supramolecular brushes.

    Science.gov (United States)

    Feng, Anchao; Yan, Qiang; Zhang, Huijuan; Peng, Liao; Yuan, Jinying

    2014-05-11

    The end-decorated homopolymer poly(ε-caprolactone)-ferrocene threaded onto a β-cyclodextrin-functionalized main-chain polymer can form a class of amphiphilic noncovalent graft copolymers based on the host-guest interactions of the terminal groups on the side chains. These new supramolecular polymer brushes can further self-assemble into micellar aggregates that exhibit reversible assembly and disassembly behavior under an electrochemical redox trigger, which opens up a new route to building dynamic block copolymer topologies. PMID:24681929

  5. Physical Organic Chemistry of Supramolecular Polymers

    Science.gov (United States)

    Serpe, Michael J.; Craig, Stephen L.

    2008-01-01

    Unlike the case of traditional covalent polymers, the entanglements that determine properties of supramolecular polymers are defined by very specific, intermolecular interactions. Recent work using modular molecular platforms to probe the mechanisms underlying mechanical response of supramolecular polymers is reviewed. The contributions of supramolecular kinetics, thermodynamics, and conformational flexibility to supramolecular polymer properties in solutions of discrete polymers, in networks, and at interfaces, are described. Molecule-to-material relationships are established through methods reminiscent of classic physical organic chemistry. PMID:17279638

  6. Remineralization of initial enamel caries in vitro using a novel peptide based on amelogenin

    Science.gov (United States)

    Li, Danxue; Lv, Xueping; Tu, Huanxin; Zhou, Xuedong; Yu, Haiyang; Zhang, Linglin

    2015-09-01

    Dental caries is the most common oral disease with high incidence, widely spread and can seriously affect the health of oral cavity and the whole body. Current caries prevention measures such as fluoride treatment, antimicrobial agents, and traditional Chinese herbal, have limitations to some extent. Here we design and synthesize a novel peptide based on the amelogenin, and assess its ability to promote the remineralization of initial enamel caries lesions. We used enamel blocks to form initial lesions, and then subjected to 12-day pH cycling in the presence of peptide, NaF and HEPES buffer. Enamel treated with peptide or NaF had shallower, narrower lesions, thicker remineralized surfaces and less mineral loss than enamel treated with HEPES. This peptide can promote the remineralization of initial enamel caries and inhibit the progress of caries. It is a promising anti-caries agent with various research prospects and practical application value.

  7. Supramolecular Packing Controls H₂ Photocatalysis in Chromophore Amphiphile Hydrogels.

    Science.gov (United States)

    Weingarten, Adam S; Kazantsev, Roman V; Palmer, Liam C; Fairfield, Daniel J; Koltonow, Andrew R; Stupp, Samuel I

    2015-12-01

    Light harvesting supramolecular assemblies are potentially useful structures as components of solar-to-fuel conversion materials. The development of these functional constructs requires an understanding of optimal packing modes for chromophores. We investigated here assembly in water and the photocatalytic function of perylene monoimide chromophore amphiphiles with different alkyl linker lengths separating their hydrophobic core and the hydrophilic carboxylate headgroup. We found that these chromophore amphiphiles (CAs) self-assemble into charged nanostructures of increasing aspect ratio as the linker length is increased. The addition of salt to screen the charged nanostructures induced the formation of hydrogels and led to internal crystallization within some of the nanostructures. For linker lengths up to seven methylenes, the CAs were found to pack into 2D crystalline unit cells within ribbon-shaped nanostructures, whereas the nine methylene CAs assembled into long nanofibers without crystalline molecular packing. At the same time, the different molecular packing arrangements after charge screening led to different absorbance spectra, despite the identical electronic properties of all PMI amphiphiles. While the crystalline CAs formed electronically coupled H-aggregates, only CAs with intermediate linker lengths showed evidence of high intermolecular orbital overlap. Photocatalytic hydrogen production using a nickel-based catalyst was observed in all hydrogels, with the highest turnovers observed for CA gels having intermediate linker lengths. We conclude that the improved photocatalytic performance of the hydrogels formed by supramolecular assemblies of the intermediate linker CA molecules likely arises from improved exciton splitting efficiencies due to their higher orbital overlap. PMID:26593389

  8. 3D Printing of Biocompatible Supramolecular Polymers and their Composites.

    Science.gov (United States)

    Hart, Lewis R; Li, Siwei; Sturgess, Craig; Wildman, Ricky; Jones, Julian R; Hayes, Wayne

    2016-02-10

    A series of polymers capable of self-assembling into infinite networks via supramolecular interactions have been designed, synthesized, and characterized for use in 3D printing applications. The biocompatible polymers and their composites with silica nanoparticles were successfully utilized to deposit both simple cubic structures, as well as a more complex twisted pyramidal feature. The polymers were found to be not toxic to a chondrogenic cell line, according to ISO 10993-5 and 10993-12 standard tests and the cells attached to the supramolecular polymers as demonstrated by confocal microscopy. Silica nanoparticles were then dispersed within the polymer matrix, yielding a composite material which was optimized for inkjet printing. The hybrid material showed promise in preliminary tests to facilitate the 3D deposition of a more complex structure.

  9. 3D Printing of Biocompatible Supramolecular Polymers and their Composites.

    Science.gov (United States)

    Hart, Lewis R; Li, Siwei; Sturgess, Craig; Wildman, Ricky; Jones, Julian R; Hayes, Wayne

    2016-02-10

    A series of polymers capable of self-assembling into infinite networks via supramolecular interactions have been designed, synthesized, and characterized for use in 3D printing applications. The biocompatible polymers and their composites with silica nanoparticles were successfully utilized to deposit both simple cubic structures, as well as a more complex twisted pyramidal feature. The polymers were found to be not toxic to a chondrogenic cell line, according to ISO 10993-5 and 10993-12 standard tests and the cells attached to the supramolecular polymers as demonstrated by confocal microscopy. Silica nanoparticles were then dispersed within the polymer matrix, yielding a composite material which was optimized for inkjet printing. The hybrid material showed promise in preliminary tests to facilitate the 3D deposition of a more complex structure. PMID:26766139

  10. A small MRI contrast agent library of gadolinium(III)-encapsulated supramolecular nanoparticles for improved relaxivity and sensitivity**

    OpenAIRE

    Chen, Kuan-Ju; Wolahan, Stephanie M.; Wang, Hao; Hsu, Chao-Hsiung; Chang, Hsing-Wei; Durazo, Armando; Hwang, Lian-Pin; Garcia, Mitch A.; Jiang, Ziyue Karen; Wu, Lily; Lin, Yung-Ya; Tseng, Hsian-Rong

    2010-01-01

    We introduce a new category of nanoparticle-based T1 MRI contrast agents (CAs) by encapsulating paramagnetic chelated gadolinium(III), i.e., Gd3+·DOTA, through supramolecular assembly of molecular building blocks that carry complementary molecular recognition motifs, including adamantane (Ad) and β-cyclodextrin (CD). A small library of Gd3+·DOTA-encapsulated supramolecular nanoparticles (Gd3+·DOTA⊂SNPs) was produced by systematically altering the molecular building block mixing ratios. A broa...

  11. 一种由[Ag(CN)2]-和Mn(Ⅱ)建筑块组装的三个三维网穿插的超分子配合物的结构和荧光性质%Three Interpenetrating 3D Related Networks and Luminescence of a Supramolecular Assembly Containing [Ag(CN)2]- and Mn(Ⅱ) Tectons

    Institute of Scientific and Technical Information of China (English)

    张建华; 董文

    2006-01-01

    Three interpenetrating 3D related networks of a cyano-bridged heterometallic supramolecular complexstate of 1 displays interesting luminescence determined by argentophilicity at room temperature. CCDC: 197205.

  12. Selective Organic and Organometallic Reactions in Water-Soluble Host-Guest Supramolecular Systems

    Energy Technology Data Exchange (ETDEWEB)

    Pluth, Michael D.; Raymond, Kenneth N.; Bergman, Robert G.

    2008-02-16

    Inspired by the efficiency and selectivity of enzymes, synthetic chemists have designed and prepared a wide range of host molecules that can bind smaller molecules with their cavities; this area has become known as 'supramolecular' or 'host-guest' chemistry. Pioneered by Lehn, Cram, Pedersen, and Breslow, and followed up by a large number of more recent investigators, it has been found that the chemical environment in each assembly - defined by the size, shape, charge, and functional group availability - greatly influences the guest-binding characteristics of these compounds. In contrast to the large number of binding studies that have been carried out in this area, the exploration of chemistry - especially catalytic chemistry - that can take place inside supramolecular host cavities is still in its infancy. For example, until the work described here was carried out, very few examples of organometallic reactivity inside supramolecular hosts were known, especially in water solution. For that reason, our group and the group directed by Kenneth Raymond decided to take advantage of our complementary expertise and attempt to carry out metal-mediated C-H bond activation reactions in water-soluble supramolecular systems. This article begins by providing background from the Raymond group in supramolecular coordination chemistry and the Bergman group in C-H bond activation. It goes on to report the results of our combined efforts in supramolecular C-H activation reactions, followed by extensions of this work into a wider range of intracavity transformations.

  13. Supramolecular assemblies of tetrafluoroterephthalic acid and N-heterocycles via various strong hydrogen bonds and weak Csbnd H⋯F interactions: Synthons cooperation, robust motifs and structural diversity

    Science.gov (United States)

    Hu, Yanjing; Hu, Hanbin; Li, Yingying; Chen, Ruixin; Yang, Yu; Wang, Lei

    2016-10-01

    A series of organic solid states including three salts, two co-crystals, and three hydrates based on tetrafluoroterephthalic acid (H2tfBDC) and N-bearing ligands (2,4-(1H,3H)-pyrimidine dione (PID), 2,4-dihydroxy-6-methyl pyrimidine (DHMPI), 2-amino-4,6-dimethyl pyrimidine (ADMPI), 2-amino-4,6-dimenthoxy pyrimidine (ADMOPI), 5,6-dimenthyl benzimidazole (DMBI), 2-aminobenzimidazole (ABI), 3,5-dimethyl pyrazole (DMP), and 3-cyanopyridine (3-CNpy)), namely, [(PID)2·(H2tfBDC)] (1), [(DHMPI)2·(H2tfBDC)] (2), [(H-ADMPI+)2·(tfBDC2-)·2(H2O)] (3), [(H-ADMOPI+)2·(tfBDC2-)·(H2O)] (4), [(H-DMBI+)2·(tfBDC2-)·2(H2O)] (5), [(H-ABI+)2·(tfBDC2-)] (6), [(H-DMP+)·(HtfBDC-)] (7), and [(H-3-CNpy+)·(HtfBDC-)] (8), were synthesized by solvent evaporation method. Crystal structures analyses show that the F atom of the H2tfBDC participates in multiple Csbnd H⋯F hydrogen bond formations, producing different supramolecular synthons. The weak hydrogen bonding Csbnd H⋯F and Nsbnd H⋯F play an important part in constructing the diversity structures 2-8, except in crystal 1. In complexes 1-3, they present the same synthon R22(8) with different N-heterocyclic compounds, which may show the strategy in constructing the supramolecular. Meanwhile, the complex 3 exhibits a 2D layer, and the independent molecules of water exist in the adjacent layers. In complexes 4 and 5, the water molecules connect the neighboring layers to form 3D network by strong Osbnd H⋯O hydrogen bonding. These crystals 1-8 were fully characterized by single-crystal X-ray crystallography, elemental analysis, infrared spectroscopy (IR), and thermogravimetric analysis (TGA).

  14. Graphene controlled H- and J-stacking of perylene dyes into highly stable supramolecular nanostructures for enhanced photocurrent generation

    DEFF Research Database (Denmark)

    Gan, Shiyu; Zhong, Lijie; Engelbrekt, Christian;

    2014-01-01

    We report a new method for controlling H- and J-stacking in supramolecular self-assembly. Graphene nanosheets act as structure inducers to direct the self-assembly of a versatile organic dye, perylene into two distinct types of functional nanostructures, i.e. one-dimensional nanotubes via J-stack...

  15. Supramolecular Organic Nanowires as Plasmonic Interconnects.

    Science.gov (United States)

    Armao, Joseph J; Domoto, Yuya; Umehara, Teruhiko; Maaloum, Mounir; Contal, Christophe; Fuks, Gad; Moulin, Emilie; Decher, Gero; Javahiraly, Nicolas; Giuseppone, Nicolas

    2016-02-23

    Metallic nanostructures are able to interact with an incident electromagnetic field at subwavelength scales by plasmon resonance which involves the collective oscillation of conduction electrons localized at their surfaces. Among several possible applications of this phenomenon, the theoretical prediction is that optical circuits connecting multiple plasmonic elements will surpass classical electronic circuits at nanoscale because of their much faster light-based information processing. However, the placement and coupling of metallic elements smaller than optical wavelengths currently remain a formidable challenge by top-down manipulations. Here, we show that organic supramolecular triarylamine nanowires of ≈1 nm in diameter are able to act as plasmonic waveguides. Their self-assembly into plasmonic interconnects between arrays of gold nanoparticles leads to the bottom-up construction of basic optical nanocircuits. When the resonance modes of these metallic nanoparticles are coupled through the organic nanowires, the optical conductivity of the plasmonic layer dramatically increases from 259 to 4271 Ω(-1)·cm(-1). We explain this effect by the coupling of a hot electron/hole pair in the nanoparticle antenna with the half-filled polaronic band of the organic nanowire. We also demonstrate that the whole hybrid system can be described by using the abstraction of the lumped circuit theory, with a far field optical response which depends on the number of interconnects. Overall, our supramolecular bottom-up approach opens the possibility to implement processable, soft, and low cost organic plasmonic interconnects into a large number of applications going from sensing to metamaterials and information technologies.

  16. Supramolecular Organic Nanowires as Plasmonic Interconnects.

    Science.gov (United States)

    Armao, Joseph J; Domoto, Yuya; Umehara, Teruhiko; Maaloum, Mounir; Contal, Christophe; Fuks, Gad; Moulin, Emilie; Decher, Gero; Javahiraly, Nicolas; Giuseppone, Nicolas

    2016-02-23

    Metallic nanostructures are able to interact with an incident electromagnetic field at subwavelength scales by plasmon resonance which involves the collective oscillation of conduction electrons localized at their surfaces. Among several possible applications of this phenomenon, the theoretical prediction is that optical circuits connecting multiple plasmonic elements will surpass classical electronic circuits at nanoscale because of their much faster light-based information processing. However, the placement and coupling of metallic elements smaller than optical wavelengths currently remain a formidable challenge by top-down manipulations. Here, we show that organic supramolecular triarylamine nanowires of ≈1 nm in diameter are able to act as plasmonic waveguides. Their self-assembly into plasmonic interconnects between arrays of gold nanoparticles leads to the bottom-up construction of basic optical nanocircuits. When the resonance modes of these metallic nanoparticles are coupled through the organic nanowires, the optical conductivity of the plasmonic layer dramatically increases from 259 to 4271 Ω(-1)·cm(-1). We explain this effect by the coupling of a hot electron/hole pair in the nanoparticle antenna with the half-filled polaronic band of the organic nanowire. We also demonstrate that the whole hybrid system can be described by using the abstraction of the lumped circuit theory, with a far field optical response which depends on the number of interconnects. Overall, our supramolecular bottom-up approach opens the possibility to implement processable, soft, and low cost organic plasmonic interconnects into a large number of applications going from sensing to metamaterials and information technologies. PMID:26814600

  17. A Supramolecular Sensing Platform for Phosphate Anions and an Anthrax Biomarker in a Microfluidic Device

    NARCIS (Netherlands)

    Eker, Bilge; Yilmaz, Mahmut Deniz; Schlautmann, Stefan; Gardeniers, Johannes G.E.; Huskens, Jurriaan

    2011-01-01

    A supramolecular platform based on self-assembled monolayers (SAMs) has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detecti

  18. Light Responsive Two-Component Supramolecular Hydrogel: A Sensitive Platform for Humidity Sensors

    KAUST Repository

    Samai, Suman

    2016-02-15

    The supramolecular assembly of anionic azobenzene dicarboxylate and cationic cetyltrimethylammonium bromide (CTAB) formed a stimuli responsive hydrogel with a critical gelation concentration (CGC) of 0.33 wt%. This self-sustainable two-component system was able to repair damage upon light irradiation. Moreover, it was successfully employed in the fabrication of highly sensitive humidity sensors for the first time.

  19. Regulating Competing Supramolecular Interactions Using Ligand Concentration.

    Science.gov (United States)

    Teunissen, Abraham J P; Paffen, Tim F E; Ercolani, Gianfranco; de Greef, Tom F A; Meijer, E W

    2016-06-01

    The complexity of biomolecular systems inevitably leads to a degree of competition between the noncovalent interactions involved. However, the outcome of biological processes is generally very well-defined often due to the competition of these interactions. In contrast, specificity in synthetic supramolecular systems is usually based on the presence of a minimum set of alternative assembly pathways. While the latter might simplify the system, it prevents the selection of specific structures and thereby limits the adaptivity of the system. Therefore, artificial systems containing competing interactions are vital to stimulate the development of more adaptive and lifelike synthetic systems. Here, we present a detailed study on the self-assembly behavior of a C2v-symmetrical tritopic molecule, functionalized with three self-complementary ureidopyrimidinone (UPy) motifs. Due to a shorter linker connecting one of these UPys, two types of cycles with different stabilities can be formed, which subsequently dimerize intermolecularly via the third UPy. The UPy complementary 2,7-diamido-1,8-naphthyridine (NaPy) motif was gradually added to this mixture in order to examine its effect on the cycle distribution. As a result of the C2v-symmetry of the tritopic UPy, together with small differences in binding strength, the cycle ratio can be regulated by altering the concentration of NaPy. We show that this ratio can be increased to an extent where one type of cycle is formed almost exclusively. PMID:27163942

  20. Orthogonal Enzymatic Reactions to Control Supramolecular Hydrogelations%Orthogonal Enzymatic Reactions to Control Supramolecular Hydrogelations

    Institute of Scientific and Technical Information of China (English)

    陈国钦; 任春华; 王玲; 徐兵; 杨志谋

    2012-01-01

    Enzyme-responsive hydrogels have great potential in applications of controlled drug release, tissue engineering, etc. In this study, we reported on a supramolecular hydrogel that showed responses to two enzymes, phosphatase which was used to form the hydrogels and esterase which could trigger gelsol phase transitions. The gelation process and visco-elasticity property of the resulting gel, morphology of the nanostructures in hydrogel, and peptide conformation in the self-assembled nanostructure were characterized by theology, transmission electron microscope (TEM), and circular dichroism (CD), respectively. Potential application of the enzyme-responsive hydrogel in drug release was also demonstrated in this study. Though only one potential application of drug release was proved in this study, the responsive hydrogel system in this study might have potentials for the applications in fields of cell culture, controlled-drug release, etc.

  1. Supramolecular nanoreactors for intracellular singlet-oxygen sensitization

    Science.gov (United States)

    Swaminathan, Subramani; Fowley, Colin; Thapaliya, Ek Raj; McCaughan, Bridgeen; Tang, Sicheng; Fraix, Aurore; Burjor, Captain; Sortino, Salvatore; Callan, John F.; Raymo, Françisco M.

    2015-08-01

    An amphiphilic polymer with multiple decyl and oligo(ethylene glycol) chains attached to a common poly(methacrylate) backbone assembles into nanoscaled particles in aqueous environments. Hydrophobic anthracene and borondipyrromethene (BODIPY) chromophores can be co-encapsulated within the self-assembling nanoparticles and transported across hydrophilic media. The reversible character of the noncovalent bonds, holding the supramolecular containers together, permits the exchange of their components with fast kinetics in aqueous solution. Incubation of cervical cancer (HeLA) cells with a mixture of two sets of nanoparticles, pre-loaded independently with anthracene or BODIPY chromophores, results in guest scrambling first and then transport of co-entrapped species to the intracellular space. Alternatively, incubation of cells with the two sets of nanocarriers in consecutive steps permits the sequential transport of the anthracene and BODIPY chromophores across the plasma membrane and only then allows their co-encapsulation within the same supramolecular containers. Both mechanisms position the two sets of chromophores with complementary spectral overlap in close proximity to enable the efficient transfer of energy intracellularly from the anthracene donors to the BODIPY acceptors. In the presence of iodine substituents on the BODIPY platform, intersystem crossing follows energy transfer. The resulting triplet state can transfer energy further to molecular oxygen with the concomitant production of singlet oxygen to induce cell mortality. Furthermore, the donor can be excited with two near-infrared photons simultaneously to permit the photoinduced generation of singlet oxygen intracellularly under illumination conditions compatible with applications in vivo. Thus, these supramolecular strategies to control the excitation dynamics of multichromophoric assemblies in the intracellular environment can evolve into valuable protocols for photodynamic therapy.An amphiphilic

  2. Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

    OpenAIRE

    Eric V. Anslyn

    2016-01-01

    While the strict definition of supramolecular chemistry is “chemistry beyond the molecule”, meaning having a focus on non-covalent interactions, the field is primarily associated with the creation of synthetic receptors and self-assembly. For synthetic ease, the receptors and assemblies routinely possess a high degree of symmetry, which lends them an aspect of aesthetic beauty. Pictures of electron orbitals similarly can be seen as akin to works of art. This similarity was an early draw for m...

  3. The supramolecular organization of the C. elegans nuclear lamin filament.

    Science.gov (United States)

    Ben-Harush, Kfir; Wiesel, Naama; Frenkiel-Krispin, Daphna; Moeller, Dorothee; Soreq, Eyal; Aebi, Ueli; Herrmann, Harald; Gruenbaum, Yosef; Medalia, Ohad

    2009-03-13

    Nuclear lamins are involved in most nuclear activities and are essential for retaining the mechano-elastic properties of the nucleus. They are nuclear intermediate filament (IF) proteins forming a distinct meshwork-like layer adhering to the inner nuclear membrane, called the nuclear lamina. Here, we present for the first time, the three-dimensional supramolecular organization of lamin 10 nm filaments and paracrystalline fibres. We show that Caenorhabditis elegans nuclear lamin forms 10 nm IF-like filaments, which are distinct from their cytoplasmic counterparts. The IF-like lamin filaments are composed of three and four tetrameric protofilaments, each of which contains two partially staggered anti-parallel head-to-tail polymers. The beaded appearance of the lamin filaments stems from paired globular tail domains, which are spaced regularly, alternating between 21 nm and 27 nm. A mutation in an evolutionarily conserved residue that causes Hutchison-Gilford progeria syndrome in humans alters the supramolecular structure of the lamin filaments. On the basis of our structural analysis, we propose an assembly pathway that yields the observed 10 nm IF-like lamin filaments and paracrystalline fibres. These results serve also as a platform for understanding the effect of laminopathic mutations on lamin supramolecular organization.

  4. Encoding complexity within supramolecular analogues of frustrated magnets

    Science.gov (United States)

    Cairns, Andrew B.; Cliffe, Matthew J.; Paddison, Joseph A. M.; Daisenberger, Dominik; Tucker, Matthew G.; Coudert, François-Xavier; Goodwin, Andrew L.

    2016-05-01

    The solid phases of gold(I) and/or silver(I) cyanides are supramolecular assemblies of inorganic polymer chains in which the key structural degrees of freedom—namely, the relative vertical shifts of neighbouring chains—are mathematically equivalent to the phase angles of rotating planar (‘XY’) spins. Here, we show how the supramolecular interactions between chains can be tuned to mimic different magnetic interactions. In this way, the structures of gold(I) and/or silver(I) cyanides reflect the phase behaviour of triangular XY magnets. Complex magnetic states predicted for this family of magnets—including collective spin-vortices of relevance to data storage applications—are realized in the structural chemistry of these cyanide polymers. Our results demonstrate how chemically simple inorganic materials can behave as structural analogues of otherwise inaccessible ‘toy’ spin models and also how the theoretical understanding of those models allows control over collective (‘emergent’) phenomena in supramolecular systems.

  5. TOPICAL REVIEW: Metallo-supramolecular modules as a paradigm for materials science

    Directory of Open Access Journals (Sweden)

    Dirk G Kurth

    2008-01-01

    Full Text Available Metal ion coordination in discrete or extended metallo-supramolecular assemblies offers ample opportunity to fabricate and study devices and materials that are equally important for fundamental research and new technologies. Metal ions embedded in a specific ligand field offer diverse thermodynamic, kinetic, chemical, physical and structural properties that make these systems promising candidates for active components in functional materials. A key challenge is to improve and develop methodologies for placing these active modules in suitable device architectures, such as thin films or mesophases. This review highlights recent developments in extended, polymeric metallo-supramolecular systems and discrete polyoxometalates with an emphasis on materials science.

  6. Directing the Crystallization of Dehydro[24]annulenes into Supramolecular Nanotubular Scaffolds.

    Science.gov (United States)

    Suzuki, Mitsuharu; Kotyk, Juliet F Khosrowabadi; Khan, Saeed I; Rubin, Yves

    2016-05-11

    The self-assembly of a series of dehydro[24]annulene derivatives into columnar stacks has been examined for its latent ability to form π-conjugated carbon-rich nanotubular structures through topochemical polymerizations. We have studied the parameters affecting self-assembly, including the nature of the substituent and crystallization conditions, using 10 different dehydro[24]annulene derivatives. In particular, hydrogen-bonding interactions through carbamate groups were found to be especially useful at directing the formation of nanotubular supramolecular assemblies. We have also evaluated the electronic coupling between neighboring dehydroannulene molecules within these supramolecular assemblies. Density functional calculations on the stacked supramolecular nanotube assemblies show that transfer integrals vary considerably between the three columnar assemblies, ranging from moderate to high (59-98 meV for the highest occupied molecular orbitals, 63-97 meV for the lowest unoccupied molecular orbitals), depending on the local molecular topology. In addition, the dehydro[24]annulene derivatives afforded distinct architectures in the crystal, including nanochannel arrays, sheets with solvent-filled pores, and lamellae. This work is an essential step toward a controlled formation of covalently linked carbon-rich nanostructures generated from molecular precursors with a latent diacetylene reactivity. PMID:27088651

  7. Supramolecular-templated synthesis of mesoporous silica-zirconia nanocomposite

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Mesoporous SiO2-ZrO2 nanocomposite was successfully prepared by using supramolecular triblock copolymer as the template through evaporation-induced self-assembly approach. The textural and structural properties were characterized by X-ray diffraction, nitrogen adsorption analysis, and transmission electron microscope.Comparison between pure mesoporous silica and mesoporous silica-zirconia nanocomposite was also presented in this work. The surface area, pore size, and pore volume decreased as the Zr doping in the mesoporous silica framework. But the obtained nanocomposite maintained the cubic Im3m-type mesoporous structure.

  8. Construction of tunable supramolecular networks studied by scanning tunneling microscopy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this review we describe a family of organic-based host frameworks which can accommodate guest molecules. The aim of the study is to test the adjustability of this class of mimic structures that may lead to new interesting functions. Emphasis of our research is placed upon four aspects: 1) thermal properties, 2) surface photochemistry, 3) fullerene adsorption, and 4) guest inclusion. It is envisioned that such approach of nanoporous molecular networks might be developed into a new family of useful soft frameworks for studies toward shape-selective catalysis, molecular recognition, self-assembly, and host-guest supramolecular chemistry.

  9. Supramolecular control over thermoresponsive polymers

    OpenAIRE

    Victor R. de la Rosa; Patrice Woisel; Richard Hoogenboom

    2016-01-01

    Thermoresponsive polymers facilitate the development of a wide range of applications in multiple areas spanning from construction or water management to lab-on-a-chip technologies and biomedical sciences. The combination of thermoresponsive polymers with supramolecular chemistry, inspired by the molecular mechanisms behind natural systems, is resulting in adaptive and smart materials with unprecedented properties. This work reviews the past advances on the combination of this young field of r...

  10. Self-healing supramolecular nanocomposites

    OpenAIRE

    Liu, Z.

    2015-01-01

    The aim of this thesis is to execute a bottom-up design of the intrinsically self-healing nanocomposites. We briefly introduced the self-healing materials in chapter 1, covering classification and basic self-healing mechanism. In chapter 2, we have synthesized polyborosiloxane (PBS) according to the last century recipe as the self-healing supramolecular matrix. Additionally, we provided the long existing recipe with exclusive supplementary details, such as reaction kinetics, structural refine...

  11. Topological dynamics in supramolecular rotors.

    Science.gov (United States)

    Palma, Carlos-Andres; Björk, Jonas; Rao, Francesco; Kühne, Dirk; Klappenberger, Florian; Barth, Johannes V

    2014-08-13

    Artificial molecular switches, rotors, and machines are set to establish design rules and applications beyond their biological counterparts. Herein we exemplify the role of noncovalent interactions and transient rearrangements in the complex behavior of supramolecular rotors caged in a 2D metal-organic coordination network. Combined scanning tunneling microscopy experiments and molecular dynamics modeling of a supramolecular rotor with respective rotation rates matching with 0.2 kcal mol(-1) (9 meV) precision, identify key steps in collective rotation events and reconfigurations. We notably reveal that stereoisomerization of the chiral trimeric units entails topological isomerization whereas rotation occurs in a topology conserving, two-step asynchronous process. In supramolecular constructs, distinct displacements of subunits occur inducing a markedly lower rotation barrier as compared to synchronous mechanisms of rigid rotors. Moreover, the chemical environment can be instructed to control the system dynamics. Our observations allow for a definition of mechanical cooperativity based on a significant reduction of free energy barriers in supramolecules compared to rigid molecules. PMID:25078022

  12. What Triggers Supramolecular Isomerism in Nonmolecular Solids? A case study of Copper Pyridazine Halides

    Indian Academy of Sciences (India)

    JENCY THOMAS; ARUNACHALAM RAMANAN

    2016-11-01

    Molecular recognition and aggregation occurring in solution are critical events towards the nucleation and growth of a crystal. However, controlling aggregation towards a particular supramolecular assembly is difficult due to lack of information on its thermodynamics and kinetics. Hence, the occurrence of supramolecularisomers is hardly recognized. In this paper, therefore, we demonstrate a retrosynthetic analysis to interpret the occurrence of isostructures and supramolecular isomers and predict the possibility of new phases in copperhalide-pyridazine- H₂O system. A significant feature of this paper is the use of crystal engineering tools, namely, synthons and tectons to interpret the phase diagram of a system. The structure-synthesis correlation discussed here provides chemical insight to evolve a synthetic protocol to interpret and predict the possibilityof supramolecular isomers in metal organic solids.

  13. Biocompatible fluorescent supramolecular nanofibrous hydrogel for long-term cell tracking and tumor imaging applications

    Science.gov (United States)

    Wang, Huaimin; Mao, Duo; Wang, Youzhi; Wang, Kai; Yi, Xiaoyong; Kong, Deling; Yang, Zhimou; Liu, Qian; Ding, Dan

    2015-11-01

    Biocompatible peptide-based supramolecular hydrogel has recently emerged as a new and promising system for biomedical applications. In this work, Rhodamine B is employed as a new capping group of self-assembling peptide, which not only provides the driving force for supramolecular nanofibrous hydrogel formation, but also endows the hydrogel with intrinsic fluroescence signal, allowing for various bioimaging applications. The fluorescent peptide nanofibrous hydrogel can be formed via disulfide bond reduction. After dilution of the hydrogel with aqueous solution, the fluorescent nanofiber suspension can be obtained. The resultant nanofibers are able to be internalized by the cancer cells and effectively track the HeLa cells for as long as 7 passages. Using a tumor-bearing mouse model, it is also demonstrated that the fluorescent supramolecular nanofibers can serve as an efficient probe for tumor imaging in a high-contrast manner.

  14. Supramolecular Rotor and Translator at Work: On-Surface Movement of Single Atoms.

    Science.gov (United States)

    Ohmann, Robin; Meyer, Jörg; Nickel, Anja; Echeverria, Jorge; Grisolia, Maricarmen; Joachim, Christian; Moresco, Francesca; Cuniberti, Gianaurelio

    2015-08-25

    A supramolecular nanostructure composed of four 4-acetylbiphenyl molecules and self-assembled on Au (111) was loaded with single Au adatoms and studied by scanning tunneling microscopy at low temperature. By applying voltage pulses to the supramolecular structure, the loaded Au atoms can be rotated and translated in a controlled manner. The manipulation of the gold adatoms is driven neither by mechanical interaction nor by direct electronic excitation. At the electronic resonance and driven by the tunneling current intensity, the supramolecular nanostructure performs a small amount of work of about 8 × 10(-21) J, while transporting the single Au atom from one adsorption site to the next. Using the measured average excitation time necessary to induce the movement, we determine the mechanical motive power of the device, yielding about 3 × 10(-21) W. PMID:26158314

  15. Supramolecular donor-acceptor hybrids of porphyrins/phthalocyanines with fullerenes/carbon nanotubes: electron transfer, sensing, switching, and catalytic applications.

    Science.gov (United States)

    D'Souza, Francis; Ito, Osamu

    2009-09-01

    Since the three-dimensional electron-accepting fullerene has been found to be an excellent building block for self-assembled supramolecular systems, we have investigated photoinduced electron transfer processes in supramolecular fullerene systems with porphyrins and phthalocyanines as electron donors to mimic natural photosynthesis. We have successfully formed self-assembled supramolecular dyads and triads via metal-ligand coordination, crown-ether inclusion, ion pairing, hydrogen-bonding, or pi-pi stacking interactions. Although the single mode of binding gives usually flexible supramolecular structures, the newly developed strategy of multiple modes of binding results in conjugates of defined distance and orientation between the donor and acceptor entities, which influences the overall electron transfer reactions. In these conjugates, we observe the anticipated acceleration of the charge separation process and deceleration of the charge recombination process. Applications of these supramolecular systems for reversible photoswitching of inter- and intramolecular electron transfer events open up new opportunities in the area of photosensors. Extension of the self-assembly approaches to single wall carbon nanotubes (SWNT) results in SWNT-porphyrin/phthalocyanine nanohybrids capable of undergoing photoinduced electron transfer. These photochemical processes lead to photocatalytic reactions accumulating redox active substances of electron acceptor/mediator entities with the help of a sacrificial electron donor. Studies on these self-assembled supramolecular dyads, triads, tetrads, etc., are only in the beginning stages and future studies anticipate involvement of more complex systems targeted for better performances in light-driven devices. PMID:19668806

  16. Elastic instability-mediated actuation by a supra-molecular polymer

    Science.gov (United States)

    Levin, Aviad; Michaels, Thomas C. T.; Adler-Abramovich, Lihi; Mason, Thomas O.; Müller, Thomas; Zhang, Bohan; Mahadevan, L.; Gazit, Ehud; Knowles, Tuomas P. J.

    2016-10-01

    In nature, fast, high-power-density actuation can be achieved through the release of stored elastic energy by exploiting mechanical instabilities in systems including the closure of the Venus flytrap and the dispersal of plant or fungal spores. Here, we use droplet microfluidics to tailor the geometry of a nanoscale self-assembling supra-molecular polymer to create a mechanical instability. We show that this strategy allows the build-up of elastic energy as a result of peptide self-assembly, and its release within milliseconds when the buckled geometry of the nanotube confined within microdroplets becomes unstable with respect to the straight form. These results overcome the inherent limitations of self-assembly for generating large-scale actuation on the sub-second timescale and illuminate the possibilities and performance limits of irreversible actuation by supra-molecular polymers.

  17. [Study on meridian tropism of medicinal property theory for Chines medicines by supramolecular chemistry (I)].

    Science.gov (United States)

    He, Fu-yuan; Deng, Kai-wen; Yang, Yan-tao; Zhou, Yi-qun; Shi, Ji-lian; Liu, Wen-long; Tang, Yu

    2015-04-01

    In this paper, based on the special influence of supramolecular chemistry on the basic theory of Chinese medicines ( CM) , the authors further analyzed the history of meridian tropism and natural origins of CM organisms and explained CM ingredients and the universal regularity of the automatic action of the supramolecular "imprinting templates" hole channel structure. After entering human bodies, CMs, as the aggregation of supramolecular "imprinting templates" , automatically seek supramolecular subjects that are matched with their "imprinting templates" in human meridians and organs for the purpose of self-recognition, self-organization, self-assembly and self-replication, so as to generate specific efficacy in meridians and organs, which is reflected as the meridian tropism phenomena at macro level. This regularity can be studied by in vitro and in vivo experimental studies. In vitro methods are mostly supra molecular structure analysis and kinetic and thermodynamic parameter calculation; Whereas in vivo methods are dominated by the analysis on object component distribution, chromatopharmacodynamic parameters and network chromatopharmacodynamic parameters; Particularly, the acupoint-medicine method can simplify to study the supramolecular subject-object relations. Consequently, CM's'meridian tropism reveals the universal regularity for interactions of macromolecular and micromolecular "imprinting templates" of subjects and objects in natural organisms. As the first barrier for the material base of the CM theory and breakthrough in the modernization of the basic CM theory, meridian tropism plays an important role in studies on basic theories of the basic CM theory.

  18. A redox responsive, fluorescent supramolecular metallohydrogel consists of nanofibers with single-molecule width

    KAUST Repository

    Zhang, Ye

    2013-04-03

    The integration of a tripeptide derivative, which is a versatile self-assembly motif, with a ruthenium(II)tris(bipyridine) complex affords the first supramolecular metallo-hydrogelator that not only self assembles in water to form a hydrogel but also exhibits gel-sol transition upon oxidation of the metal center. Surprisingly, the incorporation of the metal complex in the hydrogelator results in the nanofibers, formed by the self-assembly of the hydrogelator in water, to have the width of a single molecule of the hydrogelator. These results illustrate that metal complexes, besides being able to impart rich optical, electronic, redox, or magnetic properties to supramolecular hydrogels, also offer a unique geometrical control to prearrange the self-assembly motif prior to self-assembling. The use of metal complexes to modulate the dimensionality of intermolecular interactions may also help elucidate the interactions of the molecular nanofibers with other molecules, thus facilitating the development of supramolecular hydrogel materials for a wide range of applications. © 2013 American Chemical Society.

  19. Experimental Binding Energies in Supramolecular Complexes.

    Science.gov (United States)

    Biedermann, Frank; Schneider, Hans-Jörg

    2016-05-11

    On the basis of many literature measurements, a critical overview is given on essential noncovalent interactions in synthetic supramolecular complexes, accompanied by analyses with selected proteins. The methods, which can be applied to derive binding increments for single noncovalent interactions, start with the evaluation of consistency and additivity with a sufficiently large number of different host-guest complexes by applying linear free energy relations. Other strategies involve the use of double mutant cycles, of molecular balances, of dynamic combinatorial libraries, and of crystal structures. Promises and limitations of these strategies are discussed. Most of the analyses stem from solution studies, but a few also from gas phase. The empirically derived interactions are then presented on the basis of selected complexes with respect to ion pairing, hydrogen bonding, electrostatic contributions, halogen bonding, π-π-stacking, dispersive forces, cation-π and anion-π interactions, and contributions from the hydrophobic effect. Cooperativity in host-guest complexes as well as in self-assembly, and entropy factors are briefly highlighted. Tables with typical values for single noncovalent free energies and polarity parameters are in the Supporting Information. PMID:27136957

  20. Stabilization of reactive species by supramolecular encapsulation.

    Science.gov (United States)

    Galan, Albano; Ballester, Pablo

    2016-03-14

    Molecular containers have attracted the interest of supramolecular chemists since the early beginnings of the field. Cavitands' inner cavities were quickly exploited by Cram and Warmuth to construct covalent containers able to stabilize and assist the characterization of short-lived reactive species such as cyclobutadiene or o-benzyne. Since then, more complex molecular architectures have been prepared able to store and isolate a myriad of fleeting species (i.e. organometallic compounds, cationic species, radical initiators…). In this review we cover selected examples of the stabilization of reactive species by encapsulation in molecular containers from the first reports of covalent containers described by Cram et al. to the most recent examples of containers with self-assembled structure (metal coordination cages and hydrogen bonded capsules). Finally, we briefly review examples reported by Rebek et al. in which elusive reaction intermediates could be detected in the inner cavities of self-folding resorcin[4]arene cavitands by the formation of covalent host-guest complexes. The utilization of encapsulated reactive species in catalysis or synthesis is not covered. PMID:26797259

  1. Amelogenin gene influence on enamel defects of cleft lip and palate patients

    Directory of Open Access Journals (Sweden)

    Fernanda Veronese OLIVEIRA

    2014-08-01

    Full Text Available The aim of this study was to investigate the occurrence of mutations in the amelogenin gene (AMELX in patients with cleft lip and palate (CLP and enamel defects (ED. A total of 165 patients were divided into four groups: with CLP and ED (n=46, with CLP and without ED (n = 34, without CLP and with ED (n = 34, and without CLP or ED (n = 51. Genomic DNA was extracted from saliva followed by conducting a Polymerase Chain Reaction and direct DNA sequencing of exons 2 through 7 of AMELX. Mutations were found in 30% (n = 14, 35% (n = 12, 11% (n = 4 and 13% (n = 7 of the subjects from groups 1, 2, 3 and 4, respectively. Thirty seven mutations were detected and distributed throughout exons 2 (1 mutation – 2.7%, 6 (30 mutations – 81.08% and 7 (6 mutations – 16.22% of AMELX. No mutations were found in exons 3, 4 or 5. Of the 30 mutations found in exon 6, 43.34% (n = 13, 23.33% (n = 7, 13.33% (n = 4 and 20% (n = 6 were found in groups 1, 2, 3 and 4, respectively. c.261 C > T (rs2106416, a silent mutation, was detected in 26 subjects, and found more significantly (p = 0.003 in patients with CLP (groups 1 and 2 – 23.75%, compared with those without CLP (groups 3 and 4 – 8.23%. In the groups without ED, this silent mutation was also found more significantly (p = 0.032 among subjects with CLP (17.65% in group 2, compared with those without CLP (7.8% in group 4. In conclusion, this study suggested that AMELX may be a candidate gene for cleft lip and palate.

  2. A new multiplex assay of 17 autosomal STRs and Amelogenin for forensic application.

    Directory of Open Access Journals (Sweden)

    Suhua Zhang

    Full Text Available This paper describes a newly devised autosomal short tandem repeat (STR multiplex polymerase chain reaction (PCR systems for 17 autosomal loci (D1S1656, D2S441, D3S1358, D3S3045, D6S477, D7S3048, D8S1132, D10S1435, D10S1248, D11S2368, D13S325, D14S608, D15S659, D17S1290, D18S535, D19S253 and D22-GATA198B05 and Amelogenin. Primers for the loci were designed and optimized so that all of the amplicons were distributed from 50 base pairs (bp to less than 500 bp within a five-dye chemistry design with the fifth dye reserved for the sizing standard. Strategies were developed to overcome challenges that encountered in creating the final assay. The limits of the multiplex were tested, resulting in the successful amplification of genomic DNA range from 0.25-4 ng with 30 PCR cycles. A total of 681 individuals from the Chinese Han population were studied and forensic genetic data were present. No significant deviations from Hardy-Weinberg equilibrium were observed. A total of 180 alleles were detected for the 17 autosomal STRs. The cumulative mean exclusion chance in duos (CMECD was 0.999967, and cumulative mean exclusion chance in trios (CMECT was 0.99999995. We conclude that the present 17plex autosomal STRs assay provides an additional powerful tool for forensic applications.

  3. Massively parallel sequencing of 17 commonly used forensic autosomal STRs and amelogenin with small amplicons.

    Science.gov (United States)

    Kim, Eun Hye; Lee, Hwan Young; Yang, In Seok; Jung, Sang-Eun; Yang, Woo Ick; Shin, Kyoung-Jin

    2016-05-01

    The next-generation sequencing (NGS) method has been utilized to analyze short tandem repeat (STR) markers, which are routinely used for human identification purposes in the forensic field. Some researchers have demonstrated the successful application of the NGS system to STR typing, suggesting that NGS technology may be an alternative or additional method to overcome limitations of capillary electrophoresis (CE)-based STR profiling. However, there has been no available multiplex PCR system that is optimized for NGS analysis of forensic STR markers. Thus, we constructed a multiplex PCR system for the NGS analysis of 18 markers (13CODIS STRs, D2S1338, D19S433, Penta D, Penta E and amelogenin) by designing amplicons in the size range of 77-210 base pairs. Then, PCR products were generated from two single-sources, mixed samples and artificially degraded DNA samples using a multiplex PCR system, and were prepared for sequencing on the MiSeq system through construction of a subsequent barcoded library. By performing NGS and analyzing the data, we confirmed that the resultant STR genotypes were consistent with those of CE-based typing. Moreover, sequence variations were detected in targeted STR regions. Through the use of small-sized amplicons, the developed multiplex PCR system enables researchers to obtain successful STR profiles even from artificially degraded DNA as well as STR loci which are analyzed with large-sized amplicons in the CE-based commercial kits. In addition, successful profiles can be obtained from mixtures up to a 1:19 ratio. Consequently, the developed multiplex PCR system, which produces small size amplicons, can be successfully applied to STR NGS analysis of forensic casework samples such as mixtures and degraded DNA samples. PMID:26799314

  4. Engineering Functionalization in a Supramolecular Polymer: Hierarchical Self-Organization of Triply Orthogonal Non-covalent Interactions on a Supramolecular Coordination Complex Platform.

    Science.gov (United States)

    Zhou, Zhixuan; Yan, Xuzhou; Cook, Timothy R; Saha, Manik Lal; Stang, Peter J

    2016-01-27

    Here we present a method for the construction of functionalizable supramolecular polymers by controlling three orthogonal interactions within a single system: (i) coordination-driven self-assembly; (ii) H-bonding; and (iii) host-guest interactions between crown ether and dialkylammonium substrates. Three unique molecules constitute the supramolecular construct, including a 2-ureido-4-pyrimidinone (UPy)-functionalized rigid dipyridyl donor and a complementary organoplatinum(II) acceptor decorated with a crown ether moiety that provide the basis for self-assembly and polymerization. The final host-guest interaction is demonstrated by using one of two dialkylammonium molecules containing fluorophores that bind to the benzo-21-crown-7 (B21C7) groups of the acceptors, providing a spectroscopic handle to evaluate the functionalization. An initial coordination-driven self-assembly yields hexagonal metallacycles with alternating UPy and B21C7 groups at their vertices. The assembly does not interfere with H-bonding between the UPy groups, which link the discrete metallacycles into a supramolecular network, leaving the B21C7 groups free for functionalization via host-guest chemistry. The resultant network results in a cavity-cored metallogel at high concentrations or upon solvent swelling. The light-emitting properties of the dialkylammonium substrates were transferred to the network upon host-guest binding. This method is compatible with any dialkylammonium substrate that does not disrupt coordination nor H-bonding, and thus, the unification of these three orthogonal interactions represents a simple yet highly efficient strategy to obtain supramolecular polymeric materials with desirable functionality.

  5. Supramolecular core–shell nanoparticles for photoconductive device applications

    Science.gov (United States)

    Cheng, Chih-Chia; Chen, Jem-Kun; Shieh, Yeong-Tarng; Lee, Duu-Jong

    2016-08-01

    We report a breakthrough discovery involving supramolecular-based strategies to construct novel core–shell heterojunction nanoparticles with hydrophilic adenine-functionalized polythiophene (PAT) as the core and hydrophobic phenyl-C61-butyric acid methyl ester (PCBM) as the shell, which enables the conception of new functional supramolecular assemblies for constructing functional nanomaterials for applications in optoelectronic devices. The generated nanoparticles exhibit uniform spherical shape, well-controlled tuning of particle size with narrow size distributions, and excellent electrochemical stability in solution and the solid state owing to highly efficient energy transfer from PAT to PCBM. When the PAT/PCBM nanoparticles were fabricated into a photoconducting layer in an electronic device, the resulting device showed excellent electric conduction characteristics, including an electrically-tunable voltage-controlled switch, and high short-circuit current and open-circuit voltage. These observations demonstrate how the self-assembly of PAT/PCBM into specific nanostructures may help to promote efficient charge generation and transport processes, suggesting potential for a wide variety of applications as a promising candidate material for bulk heterojunction polymer devices.

  6. Supramolecular core-shell nanoparticles for photoconductive device applications

    Science.gov (United States)

    Cheng, Chih-Chia; Chen, Jem-Kun; Shieh, Yeong-Tarng; Lee, Duu-Jong

    2016-08-01

    We report a breakthrough discovery involving supramolecular-based strategies to construct novel core-shell heterojunction nanoparticles with hydrophilic adenine-functionalized polythiophene (PAT) as the core and hydrophobic phenyl-C61-butyric acid methyl ester (PCBM) as the shell, which enables the conception of new functional supramolecular assemblies for constructing functional nanomaterials for applications in optoelectronic devices. The generated nanoparticles exhibit uniform spherical shape, well-controlled tuning of particle size with narrow size distributions, and excellent electrochemical stability in solution and the solid state owing to highly efficient energy transfer from PAT to PCBM. When the PAT/PCBM nanoparticles were fabricated into a photoconducting layer in an electronic device, the resulting device showed excellent electric conduction characteristics, including an electrically-tunable voltage-controlled switch, and high short-circuit current and open-circuit voltage. These observations demonstrate how the self-assembly of PAT/PCBM into specific nanostructures may help to promote efficient charge generation and transport processes, suggesting potential for a wide variety of applications as a promising candidate material for bulk heterojunction polymer devices.

  7. Supramolecular core-shell nanoparticles for photoconductive device applications.

    Science.gov (United States)

    Cheng, Chih-Chia; Chen, Jem-Kun; Shieh, Yeong-Tarng; Lee, Duu-Jong

    2016-08-12

    We report a breakthrough discovery involving supramolecular-based strategies to construct novel core-shell heterojunction nanoparticles with hydrophilic adenine-functionalized polythiophene (PAT) as the core and hydrophobic phenyl-C61-butyric acid methyl ester (PCBM) as the shell, which enables the conception of new functional supramolecular assemblies for constructing functional nanomaterials for applications in optoelectronic devices. The generated nanoparticles exhibit uniform spherical shape, well-controlled tuning of particle size with narrow size distributions, and excellent electrochemical stability in solution and the solid state owing to highly efficient energy transfer from PAT to PCBM. When the PAT/PCBM nanoparticles were fabricated into a photoconducting layer in an electronic device, the resulting device showed excellent electric conduction characteristics, including an electrically-tunable voltage-controlled switch, and high short-circuit current and open-circuit voltage. These observations demonstrate how the self-assembly of PAT/PCBM into specific nanostructures may help to promote efficient charge generation and transport processes, suggesting potential for a wide variety of applications as a promising candidate material for bulk heterojunction polymer devices. PMID:27353003

  8. Thioamides: versatile bonds to induce directional and cooperative hydrogen bonding in supramolecular polymers.

    Science.gov (United States)

    Mes, Tristan; Cantekin, Seda; Balkenende, Dirk W R; Frissen, Martijn M M; Gillissen, Martijn A J; De Waal, Bas F M; Voets, Ilja K; Meijer, E W; Palmans, Anja R A

    2013-06-24

    The amide bond is a versatile functional group and its directional hydrogen-bonding capabilities are widely applied in, for example, supramolecular chemistry. The potential of the thioamide bond, in contrast, is virtually unexplored as a structuring moiety in hydrogen-bonding-based self-assembling systems. We report herein the synthesis and characterisation of a new self-assembling motif comprising thioamides to induce directional hydrogen bonding. N,N',N''-Trialkylbenzene-1,3,5-tris(carbothioamide)s (thioBTAs) with either achiral or chiral side-chains have been readily obtained by treating their amide-based precursors with P2S5. The thioBTAs showed thermotropic liquid crystalline behaviour and a columnar mesophase was assigned. IR spectroscopy revealed that strong, three-fold, intermolecular hydrogen-bonding interactions stabilise the columnar structures. In apolar alkane solutions, thioBTAs self-assemble into one-dimensional, helical supramolecular polymers stabilised by three-fold hydrogen bonding. Concentration- and temperature-dependent self-assembly studies performed by using a combination of UV and CD spectroscopy demonstrated a cooperative supramolecular polymerisation mechanism and a strong amplification of supramolecular chirality. The high dipole moment of the thioamide bond in combination with the anisotropic shape of the resulting cylindrical aggregate gives rise to sufficiently strong depolarised light scattering to enable depolarised dynamic light scattering (DDLS) experiments in dilute alkane solution. The rotational and translational diffusion coefficients, D(trans) and D(rot), were obtained from the DDLS measurements, and the average length, L, and diameter, d, of the thioBTA aggregates were derived (L = 490 nm and d = 3.6 nm). These measured values are in good agreement with the value L(w) = 755 nm obtained from fitting the temperature-dependent CD data by using a recently developed equilibrium model. This experimental verification

  9. Supramolecular Structure and Function 9

    CERN Document Server

    Pifat-Mrzljak, Greta

    2007-01-01

    The book is based on International Summer Schools on Biophysics held in Croatia which, contrary to other workshops centered mainly on one topic or technique, has very broad scope providing advanced training in areas related to biophysics. This volume is presenting papers in the field of biophysics for studying biological phenomena by using physical methods (NMR, EPR, FTIR, Mass Spectrometry, etc.) and/or concepts (predictions of protein-protein interactions, virtual ligand screening etc.). The interrelationship of supramolecular structures and there functions is enlightened by applications of principals of these physical methods in the biophysical and molecular biology context.

  10. Hydrothermal Synthesis and Characterization of a Novel Supramolecular Network Compound [Co(IN2)(H2O)4](IN=Isonicotinate)

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel supramolecular compound, [Co(IN)2(H2O)4](1), was synthesized by means of the hydrothermal method and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffraction. Though the unit cell structure of the title compound is only monomeric, all these units as building blocks are assembled into a novel three-dimensional supramolecular network via the widely hydrogen-bonding and π-π stacking interactions.

  11. 3D Supramolecular Network Based on Hydrogen Bonds Between 1D [ Ni(μ2 -C2O4 ) (Him) 2 ] Zigzag Chains

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing; HUANG Ru-dan; ZHU Qin-lei; HU Chang-wen

    2007-01-01

    @@ Introduction In recent years, considerable attention has been paid to supramolecular networks based on metal organic building blocks because of their potential applications in diverse fields, such as, catalysis, optics, sensors,magnetism, and molecular recognition[1-3]. On the basis of the principles of crystal engineering and special synthesis strategies, several novel supramolecular frameworks have been assembled from various organic,inorganic and metal-organic moieties, which largely enriches the structure chemistry of solid state materials[4-9].

  12. Amplifiability of mitochondrial, microsatellite and amelogenin DNA loci from fecal samples of red brocket deer Mazama americana (Cetartiodactyla, Cervidae).

    Science.gov (United States)

    Oliveira, M L; Duarte, J M B

    2013-01-16

    We tried to amplify mitochondrial, microsatellite and amelogenin loci in DNA from fecal samples of a wild Mazama americana population. Fifty-two deer fecal samples were collected from a 600-ha seasonal semideciduous forest fragment in a subtropical region of Brazil (21°20'S, 47°17'W), with the help of a detection dog; then, stored in ethanol and georeferenced. Among these samples 16 were classified as "fresh" and 36 as "non-fresh". DNA was extracted using the QIAamp(®) DNA Stool Mini Kit. Mitochondrial loci were amplified in 49 of the 52 samples. Five microsatellite loci were amplified by PCR; success in amplification varied according to locus size and sample age. Successful amplifications were achieved in 10/16 of the fresh and in 13/36 of the non-fresh samples; a negative correlation (R = -0.82) was found between successful amplification and locus size. Amplification of the amelogenin locus was successful in 22 of the 52 samples. The difficulty of amplifying nuclear loci in DNA samples extracted from feces collected in the field was evident. Some methodological improvements, including collecting fresh samples, selecting primers for shorter loci and quantifying the extracted DNA by real-time PCR, are suggested to increase amplification success in future studies.

  13. Fluorescent supramolecular micelles for imaging-guided cancer therapy

    Science.gov (United States)

    Sun, Mengmeng; Yin, Wenyan; Dong, Xinghua; Yang, Wantai; Zhao, Yuliang; Yin, Meizhen

    2016-02-01

    A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy.A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth

  14. Protein-based polymers that bond to DNA : design of virus-like particles and supramolecular nanostructures

    NARCIS (Netherlands)

    Hernandez Garcia, A.

    2014-01-01

     In this thesis it is demonstrated that it is possible to use Protein-based Polymers (PbPs) as synthetic binders of DNA (or any other negatively charged polyelectrolyte). The PbPs co-assemble with their DNA templates to form highly organized virus-like particles and supramolecular structures. A

  15. Hydrolytic and oxidative degradation of electrospun supramolecular biomaterials: In vitro degradation pathways.

    Science.gov (United States)

    Brugmans, M C P; Sӧntjens, S H M; Cox, M A J; Nandakumar, A; Bosman, A W; Mes, T; Janssen, H M; Bouten, C V C; Baaijens, F P T; Driessen-Mol, A

    2015-11-01

    The emerging field of in situ tissue engineering (TE) of load bearing tissues places high demands on the implanted scaffolds, as these scaffolds should provide mechanical stability immediately upon implantation. The new class of synthetic supramolecular biomaterial polymers, which contain non-covalent interactions between the polymer chains, thereby forming complex 3D structures by self assembly. Here, we have aimed to map the degradation characteristics of promising (supramolecular) materials, by using a combination of in vitro tests. The selected biomaterials were all polycaprolactones (PCLs), either conventional and unmodified PCL, or PCL with supramolecular hydrogen bonding moieties (either 2-ureido-[1H]-pyrimidin-4-one or bis-urea units) incorporated into the backbone. As these materials are elastomeric, they are suitable candidates for cardiovascular TE applications. Electrospun scaffold strips of these materials were incubated with solutions containing enzymes that catalyze hydrolysis, or solutions containing oxidative species. At several time points, chemical, morphological, and mechanical properties were investigated. It was demonstrated that conventional and supramolecular PCL-based polymers respond differently to enzyme-accelerated hydrolytic or oxidative degradation, depending on the morphological and chemical composition of the material. Conventional PCL is more prone to hydrolytic enzymatic degradation as compared to the investigated supramolecular materials, while, in contrast, the latter materials are more susceptible to oxidative degradation. Given the observed degradation pathways of the examined materials, we are able to tailor degradation characteristics by combining selected PCL backbones with additional supramolecular moieties. The presented combination of in vitro test methods can be employed to screen, limit, and select biomaterials for pre-clinical in vivo studies targeted to different clinical applications. PMID:26316031

  16. Hydrolytic and oxidative degradation of electrospun supramolecular biomaterials: In vitro degradation pathways.

    Science.gov (United States)

    Brugmans, M C P; Sӧntjens, S H M; Cox, M A J; Nandakumar, A; Bosman, A W; Mes, T; Janssen, H M; Bouten, C V C; Baaijens, F P T; Driessen-Mol, A

    2015-11-01

    The emerging field of in situ tissue engineering (TE) of load bearing tissues places high demands on the implanted scaffolds, as these scaffolds should provide mechanical stability immediately upon implantation. The new class of synthetic supramolecular biomaterial polymers, which contain non-covalent interactions between the polymer chains, thereby forming complex 3D structures by self assembly. Here, we have aimed to map the degradation characteristics of promising (supramolecular) materials, by using a combination of in vitro tests. The selected biomaterials were all polycaprolactones (PCLs), either conventional and unmodified PCL, or PCL with supramolecular hydrogen bonding moieties (either 2-ureido-[1H]-pyrimidin-4-one or bis-urea units) incorporated into the backbone. As these materials are elastomeric, they are suitable candidates for cardiovascular TE applications. Electrospun scaffold strips of these materials were incubated with solutions containing enzymes that catalyze hydrolysis, or solutions containing oxidative species. At several time points, chemical, morphological, and mechanical properties were investigated. It was demonstrated that conventional and supramolecular PCL-based polymers respond differently to enzyme-accelerated hydrolytic or oxidative degradation, depending on the morphological and chemical composition of the material. Conventional PCL is more prone to hydrolytic enzymatic degradation as compared to the investigated supramolecular materials, while, in contrast, the latter materials are more susceptible to oxidative degradation. Given the observed degradation pathways of the examined materials, we are able to tailor degradation characteristics by combining selected PCL backbones with additional supramolecular moieties. The presented combination of in vitro test methods can be employed to screen, limit, and select biomaterials for pre-clinical in vivo studies targeted to different clinical applications.

  17. Rapid fabrication of hierarchically structured supramolecular nanocomposite thin films in one minute.

    Science.gov (United States)

    Kao, Joseph; Thorkelsson, Kari; Bai, Peter; Zhang, Zhen; Sun, Cheng; Xu, Ting

    2014-01-01

    Functional nanocomposites containing nanoparticles of different chemical compositions may exhibit new properties to meet demands for advanced technology. It is imperative to simultaneously achieve hierarchical structural control and to develop rapid, scalable fabrication to minimize degradation of nanoparticle properties and for compatibility with nanomanufacturing. Here we show that the assembly kinetics of supramolecular nanocomposites in thin films are governed by the energetic cost arising from defects, the chain mobility and the activation energy for inter-domain diffusion. By optimizing only one parameter, the solvent fraction in the film, the assembly kinetics can be precisely tailored to produce hierarchically structured thin films of supramolecular nanocomposites in one minute. Moreover, the strong wavelength-dependent optical anisotropy in the nanocomposite highlights their potential applications for light manipulation and information transmission. The present study may open a new avenue in designing manufacture-friendly continuous processing for the fabrication of functional nanocomposite thin films. PMID:24887144

  18. Unveiling the molecular mechanism of self-healing in a telechelic, supramolecular polymer network

    Science.gov (United States)

    Yan, Tingzi; Schröter, Klaus; Herbst, Florian; Binder, Wolfgang H.; Thurn-Albrecht, Thomas

    2016-09-01

    Reversible polymeric networks can show self-healing properties due to their ability to reassemble after application of stress and fracture, but typically the relation between equilibrium molecular dynamics and self-healing kinetics has been difficult to disentangle. Here we present a well-characterized, self-assembled bulk network based on supramolecular assemblies, that allows a clear distinction between chain dynamics and network relaxation. Small angle x-ray scattering and rheological measurements provide evidence for a structurally well-defined, dense network of interconnected aggregates giving mechanical strength to the material. Different from a covalent network, the dynamic character of the supramolecular bonds enables macroscopic flow on a longer time scale and the establishment of an equilibrium structure. A combination of linear and nonlinear rheological measurements clearly identifies the terminal relaxation process as being responsible for the process of self-healing.

  19. A recyclable supramolecular membrane for size-selective separation of nanoparticles

    Science.gov (United States)

    Krieg, Elisha; Weissman, Haim; Shirman, Elijah; Shimoni, Eyal; Rybtchinski, Boris

    2011-03-01

    Most practical materials are held together by covalent bonds, which are irreversible. Materials based on noncovalent interactions can undergo reversible self-assembly, which offers advantages in terms of fabrication, processing and recyclability, but the majority of noncovalent systems are too fragile to be competitive with covalent materials for practical applications, despite significant attempts to develop robust noncovalent arrays. Here, we report nanostructured supramolecular membranes prepared from fibrous assemblies in water. The membranes are robust due to strong hydrophobic interactions, allowing their application in the size-selective separation of both metal and semiconductor nanoparticles. A thin (12 µm) membrane is used for filtration (~5 nm cutoff), and a thicker (45 µm) membrane allows for size-selective chromatography in the sub-5 nm domain. Unlike conventional membranes, our supramolecular membranes can be disassembled using organic solvent, cleaned, reassembled and reused multiple times.

  20. Information processing in the CNS: a supramolecular chemistry?

    Science.gov (United States)

    Tozzi, Arturo

    2015-10-01

    How does central nervous system process information? Current theories are based on two tenets: (a) information is transmitted by action potentials, the language by which neurons communicate with each other-and (b) homogeneous neuronal assemblies of cortical circuits operate on these neuronal messages where the operations are characterized by the intrinsic connectivity among neuronal populations. In this view, the size and time course of any spike is stereotypic and the information is restricted to the temporal sequence of the spikes; namely, the "neural code". However, an increasing amount of novel data point towards an alternative hypothesis: (a) the role of neural code in information processing is overemphasized. Instead of simply passing messages, action potentials play a role in dynamic coordination at multiple spatial and temporal scales, establishing network interactions across several levels of a hierarchical modular architecture, modulating and regulating the propagation of neuronal messages. (b) Information is processed at all levels of neuronal infrastructure from macromolecules to population dynamics. For example, intra-neuronal (changes in protein conformation, concentration and synthesis) and extra-neuronal factors (extracellular proteolysis, substrate patterning, myelin plasticity, microbes, metabolic status) can have a profound effect on neuronal computations. This means molecular message passing may have cognitive connotations. This essay introduces the concept of "supramolecular chemistry", involving the storage of information at the molecular level and its retrieval, transfer and processing at the supramolecular level, through transitory non-covalent molecular processes that are self-organized, self-assembled and dynamic. Finally, we note that the cortex comprises extremely heterogeneous cells, with distinct regional variations, macromolecular assembly, receptor repertoire and intrinsic microcircuitry. This suggests that every neuron (or group of

  1. Supramolecular organic frameworks: engineering periodicity in water through host-guest chemistry.

    Science.gov (United States)

    Tian, Jia; Chen, Lan; Zhang, Dan-Wei; Liu, Yi; Li, Zhan-Ting

    2016-05-11

    The development of homogeneous, water-soluble periodic self-assembled structures comprise repeating units that produce porosity in two-dimensional (2D) or three-dimensional (3D) spaces has become a topic of growing interest in the field of supramolecular chemistry. Such novel self-assembled entities, known as supramolecular organic frameworks (SOFs), are the result of programmed host-guest interactions, which allows for the thermodynamically controlled generation of monolayer sheets or a diamondoid architecture with regular internal cavities or pores under mild conditions. This feature article aims at propagating the conceptually novel SOFs as a new entry into conventional supramolecular polymers. In the first section, we will describe the background of porous solid frameworks and supramolecular polymers. We then introduce the self-assembling behaviour of several multitopic flexible molecules, which is closely related to the design of periodic SOFs from rigid multitopic building blocks. This is followed by a brief discussion of cucurbit[8]uril (CB[8])-encapsulation-enhanced aromatic stacking in water. The three-component host-guest pattern based on this stacking motif has been utilized to drive the formation of most of the new SOFs. In the following two sections, we will highlight the main advances in the construction of 2D and 3D SOFs and the related functional aspects. Finally, we will offer our opinions on future directions for both structures and functions. We hope that this article will trigger the interest of researchers in the field of chemistry, physics, biology and materials science, which should help accelerate the applications of this new family of soft self-assembled organic frameworks.

  2. Supramolecular nanofibrils inhibit cancer progression in vitro and in vivo

    Science.gov (United States)

    Kuang, Yi; Du, Xuewen; Zhou, Jie; Xu, Bing

    2014-01-01

    The recent discovery of the inverse comorbidity between cancer and Alzheimer’s disease implies that one may use amyloids to inhibit tumors. During the conversion of a dipeptide segment (Phe-Phe) in β-amyloid into a supramolecular hydrogelator, we obtained a small molecule (1) that can self-assembly into nanofibrils via multiple intermolecular hydrogen bonding and aromatic-aromatic interactions. Interestingly, while the monomers of 1 are innocuous, the nanofibrils formed by 1 can selectively inhibit the growth of glioblastoma cells over neuronal cells. To further assess the potential of this small molecular nanofibrils as anti-cancer agent, we exam the biological activity of the nanofibrils and demonstrate that the nanofibrils of 1 efficiently inhibit the progression of cancer cells (e.g., HeLa cells) both in cell assays and on xenograft mice model. This work suggests that nanofibrils derived from core motif of amyloid are effective agents for inhibiting cancer progression. Thus, this work contributes to a new approach that uses supramolecular nanofibrils as de novo molecular amyloids for inhibiting the growth of cancer cells. PMID:24574174

  3. Supramolecular architecture of endoplasmic reticulum-plasma membrane contact sites.

    Science.gov (United States)

    Fernández-Busnadiego, Rubén

    2016-04-15

    The endoplasmic reticulum (ER) forms membrane contact sites (MCS) with most other cellular organelles and the plasma membrane (PM). These ER-PM MCS, where the membranes of the ER and PM are closely apposed, were discovered in the early days of electron microscopy (EM), but only recently are we starting to understand their functional and structural diversity. ER-PM MCS are nowadays known to mediate excitation-contraction coupling (ECC) in striated muscle cells and to play crucial roles in Ca(2+)and lipid homoeostasis in all metazoan cells. A common feature across ER-PM MCS specialized in different functions is the preponderance of cooperative phenomena that result in the formation of large supramolecular assemblies. Therefore, characterizing the supramolecular architecture of ER-PM MCS is critical to understand their mechanisms of function. Cryo-electron tomography (cryo-ET) is a powerful EM technique uniquely positioned to address this issue, as it allows 3D imaging of fully hydrated, unstained cellular structures at molecular resolution. In this review I summarize our current structural knowledge on the molecular organization of ER-PM MCS and its functional implications, with special emphasis on the emerging contributions of cryo-ET. PMID:27068966

  4. Self-assembly of hydrolysed α-lactalbumin into nanotubes

    NARCIS (Netherlands)

    Graveland-Bikker, Johanna Frederike

    2005-01-01

    Self-assembly of proteins, peptides and DNA is a powerful approach for fabricating novel supramolecular architectures. Via this "bottom-up" approach many new nanomaterials have been and will be produced. Building blocks that self-assemble into fibrous materials are of special interest, because linea

  5. Probing into the Supramolecular Driving Force of an Amphiphilic β-Cyclodextrin Dimer in Various Solvents: Host-Guest Recognition or Hydrophilic-Hydrophobic Interaction?

    Science.gov (United States)

    Bai, Yang; Fan, Xiao-dong; Yao, Hao; Yang, Zhen; Liu, Ting-ting; Zhang, Hai-tao; Zhang, Wan-bin; Tian, Wei

    2015-09-01

    Tuning of the morphology and size of supramolecular self-assemblies is of theoretical and practical significance. To date, supramolecular driving forces in different solvents remain unclear. In this study, we first synthesized an amphiphilic β-cyclodextrin (β-CD) dimer that consists of one hydrophobic ibuprofen (Ibu) and two hydrophilic β-CD moieties (i.e., Ibu-CD2). Ibu-CD2 possesses double supramolecular driving forces, namely, the host-guest recognition and hydrophilic-hydrophobic interaction. The host-guest interaction of Ibu-CD2 induced the formation of branched supramolecular polymers (SPs) in pure water, whereas the hydrophilic-hydrophobic interaction generated spherical or irregular micelles in water/organic mixtures. The SP size increased with the increase in Ibu-CD2 concentration in pure water. By contrast, the size of micelles decreased with the increase in volume ratio of water in mixtures. PMID:26301920

  6. Supramolecular structures constructed from three novel rare earth metal complexes

    Indian Academy of Sciences (India)

    Huaze Dong; Xiaojun Feng; Xia Liu; BiN Zheng; Jianhong Bi; Yan Xue; Shaohua Gou; Yanping Wang

    2015-05-01

    Three rare earth metal supramolecular complexes, {[Tb(2)4](ClO4)3·2H2O(1), [Eu(2)2(H2O)5] (ClO4)3(2) and [Gd(NO3)3(2)2]·2CH3CH2OH(3) ( 2 = 3-Dimethylamino-1-pyridin-2-yl-propenone), have been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. The crystal structure analysis reveals that the coordination numbers of three complexes (1–3) are 8, 9 and 10, respectively. Three complexes assembled into 3D frameworks based on C-H⋯O, O-H⋯O hydrogen bond linkages.

  7. Building chessboard-like supramolecular structures on Au(111) surfaces

    Science.gov (United States)

    Dou, Ruifen; Yang, Yu; Zhang, Ping; Zhong, Dingyong; Fuchs, Harald; Wang, Yue; Chi, Lifeng

    2015-09-01

    We investigate an anthracene derivative, 3(5)-(9-anthryl) pyrazole (ANP), self-assembled on the Au(111) surface by means of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. A chessboard-like network structure composed of ANP molecules is found, covering the whole Au(111) substrate. Our STM results and DFT calculations reveal that the formation of chessboard-like networks originates from a basic unit cell, a tetramer structure, which is formed by four ANP molecules connected through C-H…N hydrogen bonds. The hydrogen bonds inside each tetramer and the molecule-substrate interaction are fundamentally important in providing a driving force for formation of the supramolecular networks.

  8. Size-controlled and redox-responsive supramolecular nanoparticles

    Directory of Open Access Journals (Sweden)

    Raquel Mejia-Ariza

    2015-12-01

    Full Text Available Control over the assembly and disassembly of nanoparticles is pivotal for their use as drug delivery vehicles. Here, we aim to form supramolecular nanoparticles (SNPs by combining advantages of the reversible assembly properties of SNPs using host–guest interactions and of a stimulus-responsive moiety. The SNPs are composed of a core of positively charged poly(ethylene imine grafted with β-cyclodextrin (CD and a positively charged ferrocene (Fc-terminated poly(amidoamine dendrimer, with a monovalent stabilizer at the surface. Fc was chosen for its loss of CD-binding properties when oxidizing it to the ferrocenium cation. The ionic strength was shown to play an important role in controlling the aggregate growth. The attractive supramolecular and repulsive electrostatic interactions constitute a balance of forces in this system at low ionic strengths. At higher ionic strengths, the increased charge screening led to a loss of electrostatic repulsion and therefore to faster aggregate growth. A Job plot showed that a 1:1 stoichiometry of host and guest moieties gave the most efficient aggregate growth. Different stabilizers were used to find the optimal stopper to limit the growth. A weaker guest moiety was shown to be less efficient in stabilizing the SNPs. Also steric repulsion is important for achieving SNP stability. SNPs of controlled particle size and good stability (up to seven days were prepared by fine-tuning the ratio of multivalent and monovalent interactions. Finally, reversibility of the SNPs was confirmed by oxidizing the Fc guest moieties in the core of the SNPs.

  9. Size-controlled and redox-responsive supramolecular nanoparticles.

    Science.gov (United States)

    Mejia-Ariza, Raquel; Kronig, Gavin A; Huskens, Jurriaan

    2015-01-01

    Control over the assembly and disassembly of nanoparticles is pivotal for their use as drug delivery vehicles. Here, we aim to form supramolecular nanoparticles (SNPs) by combining advantages of the reversible assembly properties of SNPs using host-guest interactions and of a stimulus-responsive moiety. The SNPs are composed of a core of positively charged poly(ethylene imine) grafted with β-cyclodextrin (CD) and a positively charged ferrocene (Fc)-terminated poly(amidoamine) dendrimer, with a monovalent stabilizer at the surface. Fc was chosen for its loss of CD-binding properties when oxidizing it to the ferrocenium cation. The ionic strength was shown to play an important role in controlling the aggregate growth. The attractive supramolecular and repulsive electrostatic interactions constitute a balance of forces in this system at low ionic strengths. At higher ionic strengths, the increased charge screening led to a loss of electrostatic repulsion and therefore to faster aggregate growth. A Job plot showed that a 1:1 stoichiometry of host and guest moieties gave the most efficient aggregate growth. Different stabilizers were used to find the optimal stopper to limit the growth. A weaker guest moiety was shown to be less efficient in stabilizing the SNPs. Also steric repulsion is important for achieving SNP stability. SNPs of controlled particle size and good stability (up to seven days) were prepared by fine-tuning the ratio of multivalent and monovalent interactions. Finally, reversibility of the SNPs was confirmed by oxidizing the Fc guest moieties in the core of the SNPs.

  10. Chiromers: conformation-driven mirror-image supramolecular chirality isomerism identified in a new class of helical rosette nanotubes

    Science.gov (United States)

    Hemraz, Usha D.; El-Bakkari, Mounir; Yamazaki, Takeshi; Cho, Jae-Young; Beingessner, Rachel L.; Fenniri, Hicham

    2014-07-01

    Rosette nanotubes are biologically inspired nanostructures, formed through the hierarchical organization of a hybrid DNA base analogue (G∧C), which features hydrogen-bonding arrays of guanine and cytosine. Several twin-G∧C motifs functionalized with chiral moieties, which undergo a self-assembly process under methanolic and aqueous conditions to produce helical rosette nanotubes (RNTs), were synthesized and characterized. The built-in molecular chirality in the twin-G∧C building blocks led to the supramolecular chirality exhibited by the RNTs, as evidenced by the CD activity. Depending on the motifs and environmental conditions, mirror-image supramolecular chirality due to absolute molecular chirality, solvent-induced and structure-dependent supramolecular chirality inversion, and pH-controlled chiroptical switching were observed.Rosette nanotubes are biologically inspired nanostructures, formed through the hierarchical organization of a hybrid DNA base analogue (G∧C), which features hydrogen-bonding arrays of guanine and cytosine. Several twin-G∧C motifs functionalized with chiral moieties, which undergo a self-assembly process under methanolic and aqueous conditions to produce helical rosette nanotubes (RNTs), were synthesized and characterized. The built-in molecular chirality in the twin-G∧C building blocks led to the supramolecular chirality exhibited by the RNTs, as evidenced by the CD activity. Depending on the motifs and environmental conditions, mirror-image supramolecular chirality due to absolute molecular chirality, solvent-induced and structure-dependent supramolecular chirality inversion, and pH-controlled chiroptical switching were observed. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00340c

  11. Supramolecular nesting of cyclic polymers

    Science.gov (United States)

    Kondratuk, Dmitry V.; Perdigão, Luís M. A.; Esmail, Ayad M. S.; O'Shea, James N.; Beton, Peter H.; Anderson, Harry L.

    2015-04-01

    Advances in template-directed synthesis make it possible to create artificial molecules with protein-like dimensions, directly from simple components. These synthetic macromolecules have a proclivity for self-organization that is reminiscent of biopolymers. Here, we report the synthesis of monodisperse cyclic porphyrin polymers, with diameters of up to 21 nm (750 C-C bonds). The ratio of the intrinsic viscosities for cyclic and linear topologies is 0.72, indicating that these polymers behave as almost ideal flexible chains in solution. When deposited on gold surfaces, the cyclic polymers display a new mode of two-dimensional supramolecular organization, combining encapsulation and nesting; one nanoring adopts a near-circular conformation, thus allowing a second nanoring to be captured within its perimeter, in a tightly folded conformation. Scanning tunnelling microscopy reveals that nesting occurs in combination with stacking when nanorings are deposited under vacuum, whereas when they are deposited directly from solution under ambient conditions there is stacking or nesting, but not a combination of both.

  12. A New Method for Sex Determination Based on Detection of SRY, STS and Amelogenin Gene Regions with Simultaneous Amplification of Their Homologous Sequences by a Multiplex PCR

    Directory of Open Access Journals (Sweden)

    Morikawa,Toshio

    2011-04-01

    Full Text Available We have developed a new method for sex determination based on simultaneous detection of the SRY (sex-determining region Y, STS (steroid sulfatase and amelogenin (AMELX and AMELY gene regions and their homologous sequences. The sex of 246 blood samples was correctly determined by this method. An AMELY-deleted male sample, which would have been erroneously considered female based solely on analysis of the amelogenin locus, was successfully identified as male by the present method. The detection limit of this method was 63 pg of genomic DNA, and the male DNA component could be detected from mixed samples having a male:female ratio as low as 1:10. This method was useful for degraded DNA and possessed the human specificity. Practical application to 35 autopsy cases is described.

  13. From supramolecular chemistry to nanotechnology : assembly of 3D nanostructures

    NARCIS (Netherlands)

    Ling, Xing Yi

    2008-01-01

    Fabricating well-defined and stable nanoparticle arrays and crystals in a controlled fashion receives growing attention in nanotechnology owing to the potential application in optoelectronic devices, biological sensors, and photonic structures. The research described in this thesis aims to construct

  14. Chlorin-based supramolecular assemblies for artificial photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Wasielewski, Michael R.; Wiederrecht, Gary P.; Svec, Walter A.; Niemczyk, Mark P. [Chemistry Division, Argonne National Laboratory, Argonne (United States)

    1995-08-01

    Photosynthetic reaction center models consisting of zinc 9-desoxo-pyrochlorophyllide, ZC, that are bonded at their 3-position to the 5-position of a 2,8,12,18-tetraethyl-3,7,13,17-tetramethylporphyrin, ZP, which is in turn bonded at its 15-position to 2-triptycenenaphthoquinone, 2-triptycenebenzoquinone, 1-triptycenebenzoquinone, or N-(4-phenyl), N`-(n-octyl)-1,4,5,8-naphthalenediimide, 1, 2, 3, and 4, respectively, were prepared. Steric hindrance between adjacent substituents positions the {pi} system of the chlorophyll perpendicular to that of the porphyrin. In turn, the {pi} system of the chlorophyll is held about 60 to that of the O-O axis of the quinones in 1 and 2, parallel to the quinone O-O axis in 3, and parallel to the N-N axis in the diimide acceptor in 4. The resulting structures place the ZC donors in 1, 2, 3 and 4 at fixed center-to-center distances of 20, 18, 14, and 21 A from the acceptors, respectively. Photoexcitation of 1-4 in 2-methyltetrahydrofuran glass at 77K results in a single observable electron transfer reaction: {sup 1}ZC-ZP-X>ZC{sup +}-ZP-X{sup -}, where X=benzoquinone (BQ), naphthoquinone (NQ) or naphthalenediimide (NI), that occurs with {tau}=4.5, 3.3, 2.0, and 2.0 ps for 1, 2, 3, and 4, respectively. The final ZC{sup +}-ZP-X{sup -} radical pairs live for 12.7, 8.4, 2.5, and 10 ms at 77K in 1, 2, 3, and 4, respectively, and exhibit spin-polarized EPR spectra characteristic of spin-correlated radical pairs. The EPR spectra of 1-4 can be simulated using the distances and orientations of the radicals relative to one another determined from the molecular structures of 1-4. These long-lived, spin-polarized radical ion pairs closely mimic the bacteriochlorophyll cation - quinone anion radical pair produced in photosynthetic reaction centers and provide a useful tool for studying the interaction of the surrounding medium with the charge separated radical ion pair

  15. Mapping the landscape of supramolecular assemblies in water

    Science.gov (United States)

    Ortony, Julia Helen

    Interactions between macromolecules in aqueous environments are the fundamental driving force behind not only a multitude of materials engineering processes, but also behind biology as a whole. While these interactions are mediated by both molecular dynamics and translational diffusion rates of interfacial water, experimental attempts to quantify these parameters have historically been inaccurate or unfeasible. Presented is a novel magnetic resonance approach to measuring dynamics in aqueous macromolecular systems. Here, electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies are united into a powerful technique termed, dynamic nuclear polarization enhanced nuclear magnetic resonance spectroscopy (DNP). This technique is implemented to characterize the internal structure of complex coacervates inspired by biological aqueous adhesives, and to probe coacervate-based triblock copolymer hydrogels with domain specificity. In addition, the role of intermolecular associations in aqueous pi-conjugated oligoelectrolytes is examined with advanced analysis tools.

  16. Supramolecular assemblies of pyridyl porphyrin and diazadithia phthalocyanine

    Directory of Open Access Journals (Sweden)

    OZER BEKAROGLU

    1999-08-01

    Full Text Available In this paper we report for the first time on a mixed complex between the cationic porphyrin 5, 10, 15, 20-tetra-N- -methyl-pyrydinium-p-il porphyrin (TMPyP and a new metal phthalocyanine with four 16-membered diazadithia macrocycles (denoted here as Pc16, in order to obtain an active complex with an intense absorption on the lower energy side of the visible spectrum and with a higher sensitivity in photodynamic therapy of cancer. The dimerization constant for Pc16 and also the ratio between the oscillator strengths for monomeric and dimeric forms of this compound, were evaluated. The ratio between these oscillator strengths was 2.01 showing a certain dimerization process. The Job mathematical method allowed the establishment of the stoichiometry and the formation constants for the heteroaggregates between the porphyrin and the phthalocy- anine (a diad between one phthalocyanine molecule and one porphyrin molecule and a triad between two phthalocyanine molecules and only one porphyrin molecule. The coulombic attraction resulting from the p-p interaction of the two highly conjugated macrocycles and from the interaction between the substituents, favors a face-to-face geometry.

  17. Towards simultaneous individual and tissue identification: A proof-of-principle study on parallel sequencing of STRs, amelogenin, and mRNAs with the Ion Torrent PGM

    OpenAIRE

    Zubakov, Dmitry; Kokmeijer, I.; Ralf, Arwin; N Rajagopalan; Calandro, L.; Wootton, S; Langit, R.; C. CHANG; Lagace, R.; Kayser, Manfred

    2015-01-01

    textabstractAbstract DNA-based individual identification and RNA-based tissue identification represent two commonly-used tools in forensic investigation, aiming to identify crime scene sample donors and helping to provide links between DNA-identified sample donors and criminal acts. Currently however, both analyses are typically performed separately. In this proof-of-principle study, we developed an approach for the simultaneous analysis of forensic STRs, amelogenin, and forensic mRNAs based ...

  18. Preparation of supramolecular hydrogel-enzyme hybrids exhibiting biomolecule-responsive gel degradation.

    Science.gov (United States)

    Shigemitsu, Hajime; Fujisaku, Takahiro; Onogi, Shoji; Yoshii, Tatsuyuki; Ikeda, Masato; Hamachi, Itaru

    2016-09-01

    Hydrogelators are small, self-assembling molecules that form supramolecular nanofiber networks that exhibit unique dynamic properties. Development of supramolecular hydrogels that degrade in response to various biomolecules could potentially be used for applications in areas such as drug delivery and diagnostics. Here we provide a synthetic procedure for preparing redox-responsive supramolecular hydrogelators that are used to create hydrogels that degrade in response to oxidizing or reducing conditions. The synthesis takes ∼2-4 d, and it can potentially be carried out in parallel to prepare multiple hydrogelator candidates. This described solid-phase peptide synthesis protocol can be used to produce previously described hydrogelators or to construct a focused molecular library to efficiently discover and optimize new hydrogelators. In addition, we describe the preparation of redox-responsive supramolecular hydrogel-enzyme hybrids that are created by mixing aqueous solutions of hydrogelators and enzymes, which requires 2 h for completion. The resultant supramolecular hydrogel-enzyme hybrids exhibit gel degradation in response to various biomolecules, and can be rationally designed by connecting the chemical reactions of the hydrogelators with enzymatic reactions. Gel degradation in response to biomolecules as triggers occurs within a few hours. We also describe the preparation of hydrogel-enzyme hybrids arrayed on flat glass slides, enabling high-throughput analysis of biomolecules such as glucose, uric acid, lactate and so on by gel degradation, which is detectable by the naked eye. The protocol requires ∼6 h to prepare the hydrogel-enzyme hybrid array and to complete the biomolecule assay. PMID:27560177

  19. Supramolecular Control over Split-Luciferase Complementation.

    Science.gov (United States)

    Bosmans, Ralph P G; Briels, Jeroen M; Milroy, Lech-Gustav; de Greef, Tom F A; Merkx, Maarten; Brunsveld, Luc

    2016-07-25

    Supramolecular split-enzyme complementation restores enzymatic activity and allows for on-off switching. Split-luciferase fragment pairs were provided with an N-terminal FGG sequence and screened for complementation through host-guest binding to cucurbit[8]uril (Q8). Split-luciferase heterocomplex formation was induced in a Q8 concentration dependent manner, resulting in a 20-fold upregulation of luciferase activity. Supramolecular split-luciferase complementation was fully reversible, as revealed by using two types of Q8 inhibitors. Competition studies with the weak-binding FGG peptide revealed a 300-fold enhanced stability for the formation of the ternary heterocomplex compared to binding of two of the same fragments to Q8. Stochiometric binding by the potent inhibitor memantine could be used for repeated cycling of luciferase activation and deactivation in conjunction with Q8, providing a versatile module for in vitro supramolecular signaling networks.

  20. X- and Y-chromosome specific variants of the amelogenin gene allow sex determination in sheep (Ovis aries and European red deer (Cervus elaphus

    Directory of Open Access Journals (Sweden)

    Brenig B

    2005-03-01

    Full Text Available Abstract Background Simple and precise methods for sex determination in animals are a pre-requisite for a number of applications in animal production and forensics. However, some of the existing methods depend only on the detection of Y-chromosome specific sequences. Therefore, the abscence of a signal does not necessarily mean that the sample is of female origin, because experimental errors can also lead to negative results. Thus, the detection of Y- and X-chromosome specific sequences is advantageous. Results A novel method for sex identification in mammals (sheep, Ovis aries and European red deer, Cervus elaphus is described, using a polymerase chain reaction (PCR and sequencing of a part of the amelogenin gene. A partial sequence of the amelogenin gene of sheep and red deer was obtained, which exists on both X and Y chromosomes with a deletion region on the Y chromosome. With a specific pair of primers a DNA fragment of different length between the male and female mammal was amplified. Conclusion PCR amplification using the amelogenin gene primers is useful in sex identification of samples from sheep and red deer and can be applied to DNA analysis of micro samples with small amounts of DNA such as hair roots as well as bones or embryo biopsies.

  1. Designed post-self-assembly structural and functional modifications of a truncated tetrahedron.

    Science.gov (United States)

    Zheng, Yao-Rong; Lan, Wen-Jie; Wang, Ming; Cook, Timothy R; Stang, Peter J

    2011-10-26

    Post-self-assembly modifications of a discrete metal-organic supramolecular structure have been developed. Such modifications allow the properties of the self-assembled supramolecular species to be changed in a simple and efficient manner (>90% yield). Initiated by the application of chemical stimuli, the post-self-assembly modifications described herein result in three distinct changes to the supramolecular system: an individual building-block component change, an overall structural modification, and a functional evolution of a [6+4] metal-organic supramolecular structure. The three modifications have been carefully examined by a range of characterization methods, including NMR and UV-vis spectroscopy, electrospray ionization mass spectrometry, pulsed field gradient spin echo NMR measurements, electrochemical analysis, and computational simulations.

  2. Dissipative self-assembly of vesicular nanoreactors.

    Science.gov (United States)

    Maiti, Subhabrata; Fortunati, Ilaria; Ferrante, Camilla; Scrimin, Paolo; Prins, Leonard J

    2016-07-01

    Dissipative self-assembly is exploited by nature to control important biological functions, such as cell division, motility and signal transduction. The ability to construct synthetic supramolecular assemblies that require the continuous consumption of energy to remain in the functional state is an essential premise for the design of synthetic systems with lifelike properties. Here, we show a new strategy for the dissipative self-assembly of functional supramolecular structures with high structural complexity. It relies on the transient stabilization of vesicles through noncovalent interactions between the surfactants and adenosine triphosphate (ATP), which acts as the chemical fuel. It is shown that the lifetime of the vesicles can be regulated by controlling the hydrolysis rate of ATP. The vesicles sustain a chemical reaction but only as long as chemical fuel is present to keep the system in the out-of-equilibrium state. The lifetime of the vesicles determines the amount of reaction product produced by the system. PMID:27325101

  3. 2D and 3D Supramolecular Assemblies from Bis(dipyridylamine) Ligands: Syntheses and Crystal Structures%双(二吡啶胺)配体的二维和三维超分子配位聚合物的合成与晶体结构

    Institute of Scientific and Technical Information of China (English)

    丁彩霞; 曾凡花; 汪成; 倪佳; 伍锡荣; 解永树

    2011-01-01

    从含4,4′-二吡啶胺结构单元的双(二吡啶胺)桥联配体出发,采用溶剂热法合成了2个结构新颖的配位聚合物:[CdL1 Br2]n·7.5nH2O[L1=N,N,N′,N′-四(4-吡啶)-1,4-苯二胺](1)和[Cu2L2(μ1.1,3-SCN)2]n·nMeOH[L2=N,N-二 (2-吡啶)-N′,N′-二(4-吡啶)-1,4-苯二胺](2),对它们进行了元素分析、红外光谱、1H NMR和紫外-可见光谱等表征,并用X射线单晶衍射测定了其晶体结构.单晶测试结果表明,配合物1中配体L1的4个吡啶N原子均参与配位,桥联了4个Cd原子,每个Cd原子与4个吡啶N原子和2个溴配位,形成六配位的八面体构型.通过这些配位作用,最终形成包含Kagome结构的三维超分子网络.配合物2是由一维柱状[Cu(SCN)]n链通过L2桥联生成的二维结构.有趣的是,L2中具有螯合能力的2,2′-二吡啶胺单元并未参与配位,只有4,4′-二吡啶胺单元中的2个吡啶N原子分别与1个Cu(Ⅰ)配位,连接了相邻2条平行的{Cu(SCN)}n链,形成二维结构.%Starting from two bis(dipyridylamine) ligands containing 4,4'-dipyridylamine moieties, two novel coordination polymers, [ CdL1 Br2 ]n ? 7. 5nH2O [ L1 = N, N, N', W-tetrakis (4-pyridyl) -1,4-phenylenedia-mine](l) and [Cu2L2(μ1,13-SCN)2]n ? rcMeOH[L2 = N,N-di(2-pyridyl)-N',N'-di(4-pyridyl-l ,4-pheny-lenediamine ] (2) , were prepared under solvothermal conditions. Their structures were characterized by elemental analyses, IR spectrum and X-ray single-crystal diffraction measurements. In complex 1, L1 utilizes all its pyridyl nitrogens to coordinate with four Cd( II ) centers to afford a three-dimensional(3D) supramolecular assembly containing Kagome structures. Complex 2 has a 2D sheet structure composed of [ CuSCN]∞ columns and bridging L2 ligands with SCN- coordinated in a rare μ1,1,3-bridging mode. It is noteworthy that the 2,2'-dipyridylamine unit of L2 is unexpectedly left noncoordinated.

  4. Brownian particles in supramolecular polymer solutions

    NARCIS (Netherlands)

    Gucht, van der J.; Besseling, N.A.M.; Knoben, W.; Bouteiller, L.; Cohen Stuart, M.A.

    2003-01-01

    The Brownian motion of colloidal particles embedded in solutions of hydrogen-bonded supramolecular polymers has been studied using dynamic light scattering. At short times, the motion of the probe particles is diffusive with a diffusion coefficient equal to that in pure solvent. At intermediate time

  5. Supramolecular liquid crystal displays : construction and applications

    NARCIS (Netherlands)

    Hoogboom, Joannes Theodorus Valentinus

    2004-01-01

    This thesis describes chemical methodologies, which can be ued to construct alignment layers for liquid crystal display purposes in a non-clean room environment, by making use of supramolecular chemistry. These techniques are subsequently used to attain control over LCD-properties, both pre- and pos

  6. Electrospinning Bioactive Supramolecular Polymers from Water

    OpenAIRE

    Tayi, Alok S.; Pashuck, E. Thomas; Newcomb, Christina J.; McClendon, Mark T.; Stupp, Samuel I.

    2014-01-01

    Electrospinning is a high-throughput, low-cost technique for manufacturing long fibers from solution. Conventionally, this technique is used with covalent polymers with large molecular weights. We report here the electrospinning of functional peptide-based supramolecular polymers from water at very low concentrations (

  7. Physical chemistry of supramolecular polymer networks

    NARCIS (Netherlands)

    Seiffert, S.; Sprakel, J.H.B.

    2012-01-01

    Supramolecular polymer networks are three-dimensional structures of crosslinked macromolecules connected by transient, non-covalent bonds; they are a fascinating class of soft materials, exhibiting properties such as stimuli-responsiveness, self-healing, and shape-memory. This critical review summar

  8. Polysaccharides: Molecular and Supramolecular Structures. Terminology.

    NARCIS (Netherlands)

    Heinze, Thomas; Petzold-Welcke, Katrin; Dam, van J.E.G.

    2012-01-01

    This chapter summarises important issues
    about the molecular and supramolecular structure
    of polysaccharides. It describes the terminology
    of polysaccharides systematically. The
    polysaccharides are divided regarding the
    molecular structures in glucans, polyoses,
    polysaccharid

  9. Supramolecular coordination polymer formed from artificial light-harvesting dendrimer.

    Science.gov (United States)

    Lee, Hosoowi; Jeong, Young-Hwan; Kim, Joo-Ho; Kim, Inhye; Lee, Eunji; Jang, Woo-Dong

    2015-09-30

    We report the formation of supramolecular coordination polymers formed from multiporphyrin dendrimers (PZnPM; M = FB or Cu), composed of the focal freebase porphyrin (PFB) or cupper porphyrin (PCu) with eight zinc porphyrin (PZn) wings, and multipyridyl porphyrins (PyPM; M = FB or Cu), PFB or PCu with eight pyridyl groups, through multiple axial coordination interactions of pyridyl groups to PZns. UV-vis absorption spectra were recorded upon titration of PyPFB to PZnPFB. Differential spectra, obtained by subtracting the absorption of PZnPFB without guest addition as well as the absorption of PyPFB, exhibited clear isosbestic points with saturation binding at 1 equiv addition of PyPFB to PZnPFB. Job's plot analysis also indicated 1:1 stoichiometry for the saturation binding. The apparent association constant between PZnPFB and PyPFB (2.91 × 10(6) M(-1)), estimated by isothermal titration calorimetry, was high enough for fibrous assemblies to form at micromolar concentrations. The formation of a fibrous assembly from PZnPFB and PyPFB was visualized by atomic force microscopy and transmission electron microscopy (TEM). When a 1:1 mixture solution of PZnPFB and PyPFB (20 μM) in toluene was cast onto mica, fibrous assemblies with regular height (ca. 2 nm) were observed. TEM images obtained from 1:1 mixture solution of PZnPFB and PyPFB (0.1 wt %) in toluene clearly showed the formation of nanofibers with a regular diameter of ca. 6 nm. Fluorescence emission measurement of PZnPM indicated efficient intramolecular energy transfer from PZn to the focal PFB or PCu. By the formation of supramolecular coordination polymers, the intramolecular energy transfer changed to intermolecular energy transfer from PZnPM to PyPM. When the nonfluorescent PyPCu was titrated to fluorescent PZnPFB, fluorescence emission from the focal PFB was gradually decreased. By the titration of fluorescent PyPFB to nonfluorescent PZnPCu, fluorescence emission from PFB in PyPFB was gradually increased

  10. Application of a supramolecular-ligand library for the automated search for catalysts for the asymmetric hydrogenation of industrially relevant substrates

    NARCIS (Netherlands)

    J. Meeuwissen; M. Kuil; A.M. van der Burg; A.J. Sandee; J.N.H. Reek

    2009-01-01

    A procedure is described for the automated screening and lead optimization of a supramolecular-ligand library for the rhodium-catalyzed asymmetric hydrogenation of five challenging substrates relevant to industry. Each catalyst is (self-) assembled from two urea-functionalized ligands and a transiti

  11. Supramolecular Organization of Functional Dendrimers

    Institute of Scientific and Technical Information of China (English)

    D.Guillon; B.Donnio

    2007-01-01

    1 Results The possibility to develop large multifunctional macromolecular structures which can further self-assemble into nanosized objects,makes liquid-crystalline dendrimers highly attractive candidates in the field of materials science and may represent an original strategy for the realisation of molecular electronic-based devices[1-2].Sophisticated nanostructures obtained with dendrimers where mesogenic groups are not only located at the periphery of the dendrimer[3] but also at the branching points...

  12. Shell-sheddable, pH-sensitive supramolecular nanoparticles based on ortho ester-modified cyclodextrin and adamantyl PEG.

    Science.gov (United States)

    Ji, Ran; Cheng, Jing; Yang, Ting; Song, Cheng Cheng; Li, Lei; Du, Fu-Sheng; Li, Zi-Chen

    2014-10-13

    We report a new type of pH-sensitive supramolecular aggregates which possess a programmable character of sequential dePEGylation and degradation. As a platform of designing and building multifunctional supramolecular nanoparticles, a family of 6-OH ortho ester-modified β-cyclodextrin (β-CD) derivatives have been synthesized via the facile reaction between β-CD and cyclic ketene acetals with different alkyl lengths. These asymmetric acid-labile β-CD derivatives formed amphiphilic supramolecules with adamantane-modified PEG through host-guest interaction in polar solvents such as ethanol. The supramolecules can self-assemble in water to form acid-labile supramolecular aggregates. The results of TEM and light scattering measurements demonstrate that the size and morphology of the aggregates are influenced by the alkyl or PEG length and the host-guest feed ratio. By carefully balancing the alkyl and PEG lengths and adjusting the host-guest ratio, well-dispersed vesicles (50-100 nm) or sphere-like nanoparticles (200-500 nm) were obtained. Zeta potential measurements reveal that these supramolecular aggregates are capable of being surface-functionalized via dynamic host-guest interaction. The supramolecular aggregates were stable at pH 8.4 for at least 12 h as proven by the (1)H NMR and LLS measurements. However, rapid dePEGylation occurred at pH 7.4 due to the hydrolysis of the ortho ester linkages locating at the interface, which resulted in aggregation of the dePEGylated hydrophobic inner cores. Upon further decreasing the pH to 6.4, the hydrophobic cores were further degraded due to the acid-accelerated hydrolysis of the ortho esters. The incubation stability of the acid-labile supramolecular aggregates in neutral buffer could be improved by incorporating hydrophobic poly(ε-caprolactone) into the core of the aggregates. PMID:25144934

  13. Supramolecular interfacial architectures for optical biosensing with surface plasmons

    Science.gov (United States)

    Knoll, Wolfgang; Park, Hyeyoung; Sinner, Eva-Kathrin; Yao, Danfeng; Yu, Fang

    2004-10-01

    We describe several approaches to design, synthesize and assemble supramolecular (bio-)functional interfacial architectures for applications in optical biosensing using, in particular, surface plasmon field-enhanced fluorescence spectroscopy (SPFS). Firstly, we discuss the build-up of an interfacial catcher probe layer for surface-hybridization studies with PCR amplicons. The well-established biotin-streptavidin coupling scheme is used to assemble a peptide nucleic acid (PNA) probe matrix. SPFS allows then for a very detailed and quantitative evaluation of the kinetics and affinities of the association and dissociation reactions between these catcher oligonucleotide strands and chromophore-labeled PCR (125 bp) strands from solution. The second example concerns the study of protein binding using an ELISA-analogue sandwich approach: a primary antibody against the prostate-specific antigen (PSA) used in these examples is coupled to a dextran binding matrix at the sensor surface via EDC/NHS-coupling. The detection limits for PSA are then evaluated using a 2-step- or 1-step-antigen/secondary antibody strategy by monitoring the fluorescence intensity emitted from chromophore-labels covalently bound to the secondary antibody. The final system that we describe involves a novel model membrane system, i.e., a tethered bimolecular lipid membrane (tBLM). Reconstitution of integrin receptors then allows for a quantitative study of the binding of fluorophore-labeled collagen fragments to the membrane-based integrin receptors.

  14. Inversion of Supramolecular Chirality by Sonication-Induced Organogelation

    Science.gov (United States)

    Maity, Sibaprasad; Das, Priyadip; Reches, Meital

    2015-11-01

    Natural helical structures have inspired the formation of well-ordered peptide-based chiral nanostructures in vitro. These structures have drawn much attention owing to their diverse applications in the area of asymmetric catalysts, chiral photonic materials, and nanoplasmonics. The self-assembly of two enantiomeric fluorinated aromatic dipeptides into ordered chiral fibrillar nanostructures upon sonication is described. These fibrils form organogels. Our results clearly indicate that fluorine-fluorine interactions play an important role in self-assembly. Circular dichroism analysis revealed that both peptides (peptides 1 and 2), containing two fluorines, depicted opposite cotton effects in their monomeric form compared with their aggregated form. This shows that supramolecular chirality inversion took place during the stimuli-responsive self-aggregation process. Conversely, peptide 3, containing one fluorine, did not exhibit chirality inversion in sonication-induced organogelation. Therefore, our results clearly indicate that fluorination plays an important role in the organogelation process of these aromatic dipeptides. Our findings may have broad implications regarding the design of chiral nanostructures for possible applications such as chiroptical switches, asymmetric catalysis, and chiral recognitions.

  15. Self-assembled peptide nanostructures for functional materials

    Science.gov (United States)

    Sardan Ekiz, Melis; Cinar, Goksu; Aref Khalily, Mohammad; Guler, Mustafa O.

    2016-10-01

    Nature is an important inspirational source for scientists, and presents complex and elegant examples of adaptive and intelligent systems created by self-assembly. Significant effort has been devoted to understanding these sophisticated systems. The self-assembly process enables us to create supramolecular nanostructures with high order and complexity, and peptide-based self-assembling building blocks can serve as suitable platforms to construct nanostructures showing diverse features and applications. In this review, peptide-based supramolecular assemblies will be discussed in terms of their synthesis, design, characterization and application. Peptide nanostructures are categorized based on their chemical and physical properties and will be examined by rationalizing the influence of peptide design on the resulting morphology and the methods employed to characterize these high order complex systems. Moreover, the application of self-assembled peptide nanomaterials as functional materials in information technologies and environmental sciences will be reviewed by providing examples from recently published high-impact studies.

  16. Study on the supramolecular structure of sorbic acid intercalated Zn-Al layered double hydroxides and its thermal decomposition

    Institute of Scientific and Technical Information of China (English)

    MENG Jinhong; ZHANG Hui; David G. Evans; DUAN Xue

    2005-01-01

    A novel organic-inorganic composite, sorbic acid intercalated zinc aluminum layered double hydroxides (SA-ZnAl-LDHs) has been successfully assembled by a simple direct coprecipitation method. A holistic approach including normal XRD, FT-IR, and UV-Vis measurements and simultaneous TG/DTA/MS and in situ HT-XRD techniques was employed to explore the supramolecular intercalation structure and the thermal decomposition properties of as-synthesized SA-ZnAl-LDHs material.

  17. Supramolecular organization in organic-inorganic heterogeneous hybrid catalysts formed from polyoxometalate and poly(ampholyte) polymer.

    Science.gov (United States)

    Raj, Gijo; Swalus, Colas; Guillet, Alain; Devillers, Michel; Nysten, Bernard; Gaigneaux, Eric M

    2013-04-01

    Hybridization of polyoxometalates (POMs) via the formation of an organic-inorganic association constitutes a new route to develop a heterogeneous POM catalyst with tunable functionality imparted through supramolecular assembly. Herein, we report on strategies to obtain tunable well-defined supramolecular architectures of an organic-inorganic heterogeneous hybrid catalyst formed by the association of a hydrophobically substituted polyampholyte copolymer (poly N, N-diallyl-N-hexylamine-alt-maleic acid) and phosphotungstic acid (H3PW12O40) POMs. The self-assembling property of the initial polyampholyte copolymer matrix is modulated by controlling the pH of the hybridization solution. When deposited on a mica surface, isolated, long and extended polymer chains are formed under basic conditions (pH 7.9), while globular or coiled structures are formed under acidic conditions (pH 2). The supramolecular assembly of the POM-polymer hybrid is found to be directed by the type and quantities of charges present on the polyampholyte copolymer, which themselves depend on the pH conditions. The hypothesis is that the Keggin type [PW12O40](3-) anions, which have a size of ~1 nm, electrostatically bind to the positive charge sites of the polymer backbone. The hybrid material stabilized at pH 5.3 consists of POM-decorated polymer chains. Statistical analysis of distances between pairs of POM entities show narrow density distributions, suggesting that POM entities are attached to the polymer chains with a high level of order. Conversely, under acidic conditions (pH 2), the hybrid shows the formation of a core-shell type of structure. The strategies reported here, to tune the supramolecular assembly of organic-inorganic hybrid materials, are highly valuable for the design and a more rational utilization of POM heterogeneous catalysts in several chemical transformations.

  18. Discrete stimuli-responsive multirotaxanes with supramolecular cores constructed through a modular approach.

    Science.gov (United States)

    Wang, Wei; Sun, Bin; Wang, Xu-Qing; Ren, Yuan-Yuan; Chen, Li-Jun; Ma, Jianqiu; Zhang, Yanyan; Li, Xiaopeng; Yu, Yihua; Tan, Hongwei; Yang, Hai-Bo

    2015-04-13

    The synthesis of discrete multirotaxanes with well-defined structures remains a great challenge. Herein, we present the successful construction of diverse discrete multirotaxanes with well-defined supramolecular metallacycles as cores by a modular approach. Moreover, these novel multirotaxanes featured a stimuli-responsive property that enabled the introduction and removal of the bromide anion by taking advantage of dynamic nature of the supramolecular metallacycle scaffold. Through the combination of rotaxane-containing prefunctionalized building blocks with the corresponding different organoplatinum(II) acceptor building blocks (60, 120, or 180°), diverse discrete multirotaxanes with well-defined metallacycles (rhomboid or hexagon) as cores as well as certain numbers of rotaxane units were successfully obtained quantitatively by means of coordination-driven self-assembly. Furthermore, owing to the existence of a dynamic metallacycle as the supramolecular cores, the resultant multirotaxanes showed anion-induced disassembly and reassembly properties, which allowed for the reversible transformation between multirotaxanes and the corresponding individual rotaxane-containing building blocks. Therefore, this research not only enriches the family of discrete multirotaxanes, but also provides a novel strategy for the construction of "smart" stimuli-responsive multirotaxane systems.

  19. Making hybrid [n]-rotaxanes as supramolecular arrays of molecular electron spin qubits

    Science.gov (United States)

    Fernandez, Antonio; Ferrando-Soria, Jesus; Pineda, Eufemio Moreno; Tuna, Floriana; Vitorica-Yrezabal, Iñigo J.; Knappke, Christiane; Ujma, Jakub; Muryn, Christopher A.; Timco, Grigore A.; Barran, Perdita E.; Ardavan, Arzhang; Winpenny, Richard E. P.

    2016-01-01

    Quantum information processing (QIP) would require that the individual units involved--qubits--communicate to other qubits while retaining their identity. In many ways this resembles the way supramolecular chemistry brings together individual molecules into interlocked structures, where the assembly has one identity but where the individual components are still recognizable. Here a fully modular supramolecular strategy has been to link hybrid organic-inorganic [2]- and [3]-rotaxanes into still larger [4]-, [5]- and [7]-rotaxanes. The ring components are heterometallic octanuclear [Cr7NiF8(O2CtBu)16]- coordination cages and the thread components template the formation of the ring about the organic axle, and are further functionalized to act as a ligand, which leads to large supramolecular arrays of these heterometallic rings. As the rings have been proposed as qubits for QIP, the strategy provides a possible route towards scalable molecular electron spin devices for QIP. Double electron-electron resonance experiments demonstrate inter-qubit interactions suitable for mediating two-qubit quantum logic gates.

  20. Free-Standing Monolayer Two-Dimensional Supramolecular Organic Framework with Good Internal Order.

    Science.gov (United States)

    Pfeffermann, Martin; Dong, Renhao; Graf, Robert; Zajaczkowski, Wojciech; Gorelik, Tatiana; Pisula, Wojciech; Narita, Akimitsu; Müllen, Klaus; Feng, Xinliang

    2015-11-18

    Utilizing dynamic self-assembly and self-sorting to obtain large-area, molecularly precise monolayered structures represents a promising approach toward two-dimensional supramolecular organic frameworks (2D SOF) or 2D supramolecular polymers. So far, related approaches suffer from small domain sizes, fragility and weak long-range internal order. Here we report on the self-assembly of a host-guest enhanced donor-acceptor interaction, consisting of a tris(methoxynaphthyl)-substituted truxene spacer, and a naphthalene diimide substituted with N-methyl viologenyl moieties as donor and acceptor monomers, respectively, in combination with cucurbit[8]uril as host monomer toward monolayers of an unprecedented 2D SOF. Featuring orthogonal solubility, the participating molecules self-assemble at a liquid-liquid interface, yielding exceptionally large-area, insoluble films, which were analyzed by transmission electron microscopy, atomic force microscopy and optical microscopy to be monolayers with a thickness of 1.8 nm, homogeneously covering areas up to 0.25 cm(2), and featuring the ability to be free-standing over holes of 10 μm(2). Characterization with ultraviolet-visible absorption spectroscopy, solid-state nuclear magnetic resonance spectroscopy, infrared spectroscopy, and grazing incidence wide-angle X-ray scattering allowed for confirmation of a successful complexation of all three monomers toward an internal long-range order and gave indications to an expected hexagonal superstructure. Our results extend the existing variety of two-dimensional soft nanomaterials by a versatile supramolecular approach, whereas the possibility of varying the functional monomers is supposed to open adaptability to different applications like membranes, sensors, molecular sieves, and optoelectronics. PMID:26529142

  1. Supramolecular metal-organic frameworks that display high homogeneous and heterogeneous photocatalytic activity for H2 production

    Science.gov (United States)

    Tian, Jia; Xu, Zi-Yue; Zhang, Dan-Wei; Wang, Hui; Xie, Song-Hai; Xu, Da-Wen; Ren, Yuan-Hang; Wang, Hao; Liu, Yi; Li, Zhan-Ting

    2016-05-01

    Self-assembly has a unique presence when it comes to creating complicated, ordered supramolecular architectures from simple components under mild conditions. Here, we describe a self-assembly strategy for the generation of the first homogeneous supramolecular metal-organic framework (SMOF-1) in water at room temperature from a hexaarmed [Ru(bpy)3]2+-based precursor and cucurbit[8]uril (CB[8]). The solution-phase periodicity of this cubic transition metal-cored supramolecular organic framework (MSOF) is confirmed by small-angle X-ray scattering and diffraction experiments, which, as supported by TEM imaging, is commensurate with the periodicity in the solid state. We further demonstrate that SMOF-1 adsorbs anionic Wells-Dawson-type polyoxometalates (WD-POMs) in a one-cage-one-guest manner to give WD-POM@SMOF-1 hybrid assemblies. Upon visible-light (500 nm) irradiation, such hybrids enable fast multi-electron injection from photosensitive [Ru(bpy)3]2+ units to redox-active WD-POM units, leading to efficient hydrogen production in aqueous media and in organic media. The demonstrated strategy opens the door for the development of new classes of liquid-phase and solid-phase ordered porous materials.

  2. Metallo-supramolecular block copolymers : from synthesis to smart nanomaterials

    OpenAIRE

    Guillet, Pierre

    2008-01-01

    Supramolecular copolymers have become of increasing interest in recent years for the search of new materials with tunable properties. In particular, metallo-supramolecular block copolymers have seen important progresses since the last five years. In this thesis, a library of metallo-supramolecular amphiphilic block copolymers containing a hydrophilic block, linked to a hydrophobic block, through a metal-ligand complex has been investigated. The micelles formed in water from these copolymers...

  3. Host-guest supramolecular nanosystems for cancer diagnostics and therapeutics.

    Science.gov (United States)

    Wang, Lei; Li, Li-li; Fan, Yun-shan; Wang, Hao

    2013-07-26

    Extensive efforts have been devoted to the construction of functional supramolecular nanosystems for applications in catalysis, energy conversion, sensing and biomedicine. The applications of supramolecular nanosystems such as liposomes, micelles, inorganic nanoparticles, carbon materials for cancer diagnostics and therapeutics have been reviewed by other groups. Here, we will focus on the recent momentous advances in the implementation of typical supramolecular hosts (i.e., cyclodextrins, calixarenes, cucurbiturils and metallo-hosts) and their nanosystems in cancer diagnostics and therapeutics. We discuss the evolutive process of supramolecular nanosystems from the structural control and characterization to their diagnostic and therapeutic function exploitation and even the future potentials for clinical translation.

  4. A highly polymorphic insertion in the Y-chromosome amelogenin gene can be used for evolutionary biology, population genetics and sexing in Cetacea and Artiodactyla

    Directory of Open Access Journals (Sweden)

    Crouau-Roy Brigitte

    2008-10-01

    Full Text Available Abstract Background The early radiation of the Cetartiodactyla is complex, and unambiguous molecular characters are needed to clarify the positions of hippotamuses, camels and pigs relative to the remaining taxa (Cetacea and Ruminantia. There is also a need for informative genealogic markers for Y-chromosome population genetics as well as a sexing method applicable to all species from this group. We therefore studied the sequence variation of a partial sequence of the evolutionary conserved amelogenin gene to assess its potential use in each of these fields. Results and discussion We report a large interstitial insertion in the Y amelogenin locus in most of the Cetartiodactyla lineages (cetaceans and ruminants. This sex-linked size polymorphism is the result of a 460–465 bp inserted element in intron 4 of the amelogenin gene of Ruminants and Cetaceans. Therefore, this polymorphism can easily be used in a sexing assay for these species. When taking into account this shared character in addition to nucleotide sequence, gene genealogy follows sex-chromosome divergence in Cetartiodactyla whereas it is more congruent with zoological history when ignoring these characters. This could be related to a loss of homology between chromosomal copies given the old age of the insertion. The 1 kbp Amel-Y amplified fragment is also characterized by high nucleotide diversity (64 polymorphic sites spanning over 1 kbp in seven haplotypes which is greater than for other Y-chromosome sequence markers studied so far but less than the mitochondrial control region. Conclusion The gender-dependent polymorphism we have identified is relevant not only for phylogenic inference within the Cetartiodactyla but also for Y-chromosome based population genetics and gender determination in cetaceans and ruminants. One single protocol can therefore be used for studies in population and evolutionary genetics, reproductive biotechnologies, and forensic science.

  5. Supramolecular Liquid Crystallinity: Spherical Coils of Levan Surrounding Cylindrical Rods of DNA

    Science.gov (United States)

    Huber, Anne E.; Viney, Christopher

    1998-01-01

    Levan, which adopts a compact spherical conformation in aqueous solution, can form a liquid crystalline phase if DNA is also present. We propose that supramolecular rodlike structures, assembled by the noncovalent aggregation of levan around DNA, stabilize the lyotropic phase. We describe a geometric model for the aggregates. The model is quantitatively consistent with the relative amounts of DNA and levan needed for liquid crystallinity, and it agrees qualitatively with the shape of the boundary between the isotropic and heterogeneous fields on an experimentally determined phase diagram.

  6. Supramolecular chemistry at interfaces: host-guest interactions for fabricating multifunctional biointerfaces.

    Science.gov (United States)

    Yang, Hui; Yuan, Bin; Zhang, Xi; Scherman, Oren A

    2014-07-15

    CONSPECTUS: Host-guest chemistry can greatly improve the selectivity of biomolecule-ligand binding on account of recognition-directed interactions. In addition, functional structures and the actuation of supramolecular assemblies in molecular systems can be controlled efficiently through various host-guest chemistry. Together, these highly selective, strong yet dynamic interactions can be exploited as an alternative methodology for applications in the field of programmable and controllable engineering of supramolecular soft materials through the reversible binding between complementary components. Many processes in living systems such as biotransformation, transportation of matter, and energy transduction begin with interfacial molecular recognition, which is greatly influenced by various external stimuli at biointerfaces. Detailed investigations about the molecular recognition at interfaces can result in a better understanding of life science, and further guide us in developing new biomaterials and medicines. In order to mimic complicated molecular-recognition systems observed in nature that adapt to changes in their environment, combining host-guest chemistry and surface science is critical for fabricating the next generation of multifunctional biointerfaces with efficient stimuli-responsiveness and good biocompatibility. In this Account, we will summarize some recent progress on multifunctional stimuli-responsive biointerfaces and biosurfaces fabricated by cyclodextrin- or cucurbituril-based host-guest chemistry and highlight their potential applications including drug delivery, bioelectrocatalysis, and reversible adsorption and resistance of peptides, proteins, and cells. In addition, these biointerfaces and biosurfaces demonstrate efficient response toward various external stimuli, such as UV light, pH, redox chemistry, and competitive guests. All of these external stimuli can aid in mimicking the biological stimuli evident in complex biological environments

  7. Supramolecular structure of electroactive polymer thin films

    Science.gov (United States)

    Kornilov, V. M.; Lachinov, A. N.; Karamov, D. D.; Nabiullin, I. R.; Kul'velis, Yu. V.

    2016-05-01

    This paper presents the results of an experimental investigation of the supramolecular structure of polydiphenylenephthalide thin films that exhibit effects of resistive switching. The supramolecular structure of the polymer has been investigated using small-angle neutron scattering in conjunction with atomic force microscopy. It has been found that the internal structure of polymer films consists of structural elements in the form of spheroids. The sizes of the structural elements, which were obtained from the neutron scattering data and analysis of the atomic force microscopy images, correlate well with each other. A model of the formation of polymer layers has been proposed. The observed structural elements in polymer films are formed due to the association of macromolecules in the initial polymer solution.

  8. Supramolecular nanoparticles that target phosphoinositide-3-kinase overcome insulin resistance and exert pronounced antitumor efficacy.

    Science.gov (United States)

    Kulkarni, Ashish A; Roy, Bhaskar; Rao, Poornima S; Wyant, Gregory A; Mahmoud, Ayaat; Ramachandran, Madhumitha; Sengupta, Poulomi; Goldman, Aaron; Kotamraju, Venkata Ramana; Basu, Sudipta; Mashelkar, Raghunath A; Ruoslahti, Erkki; Dinulescu, Daniela M; Sengupta, Shiladitya

    2013-12-01

    The centrality of phosphoinositide-3-kinase (PI3K) in cancer etiology is well established, but clinical translation of PI3K inhibitors has been limited by feedback signaling, suboptimal intratumoral concentration, and an insulin resistance "class effect." This study was designed to explore the use of supramolecular nanochemistry for targeting PI3K to enhance antitumor efficacy and potentially overcome these limitations. PI3K inhibitor structures were rationally modified using a cholesterol-based derivative, facilitating supramolecular nanoassembly with L-α-phosphatidylcholine and DSPE-PEG [1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polythylene glycol)]. The supramolecular nanoparticles (SNP) that were assembled were physicochemically characterized and functionally evaluated in vitro. Antitumor efficacy was quantified in vivo using 4T1 breast cancer and K-Ras(LSL/+)/Pten(fl/fl) ovarian cancer models, with effects on glucose homeostasis evaluated using an insulin sensitivity test. The use of PI103 and PI828 as surrogate molecules to engineer the SNPs highlighted the need to keep design principles in perspective; specifically, potency of the active molecule and the linker chemistry were critical principles for efficacy, similar to antibody-drug conjugates. We found that the SNPs exerted a temporally sustained inhibition of phosphorylation of Akt, mTOR, S6K, and 4EBP in vivo. These effects were associated with increased antitumor efficacy and survival as compared with PI103 and PI828. Efficacy was further increased by decorating the nanoparticle surface with tumor-homing peptides. Notably, the use of SNPs abrogated the insulin resistance that has been associated widely with other PI3K inhibitors. This study provides a preclinical foundation for the use of supramolecular nanochemistry to overcome current challenges associated with PI3K inhibitors, offering a paradigm for extension to other molecularly targeted therapeutics being explored for cancer

  9. An injectable, dual pH and oxidation-responsive supramolecular hydrogel for controlled dual drug delivery.

    Science.gov (United States)

    Cheng, Xinfeng; Jin, Yong; Sun, Tongbing; Qi, Rui; Li, Hanping; Fan, Wuhou

    2016-05-01

    A novel pH and oxidation dual-responsive and injectable supramolecular hydrogel was developed, which was formed from multi-block copolymer poly(ether urethane) (PEU) and α-cyclodextrin (α-CD) inclusion complexes (ICs). The PEU copolymer was synthesized through a simple one-pot condensation polymerization of poly(ethylene glycol), di(1-hydroxyethylene) diselenide, dimethylolpropionic acid and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate. In aqueous solution, the amphiphilic PEU copolymers could self-assemble into nanoparticles with dual pH and oxidation sensitivities, which can efficiently load and controllably release a hydrophobic drug indomethacin (IND). Then a dual-drug loaded supramolecular hydrogel was obtained by addition of α-CD and hydrophilic model drug (rhodamine B, RB) into the resulting IND-loaded PEU nanoparticle solution. The rheology studies showed that the supramolecular hydrogels with good injectability underwent a pH-induced reversible sol-gel transition and an oxidation-triggered degradation behavior. The in vitro drug release results demonstrated that the hydrogels showed dual drug release behavior and the release rates could be significantly accelerated by addition of an oxidizing agent (H2O2) or increasing the environmental pH. Therefore, this injectable and dual stimuli-responsive supramolecular hydrogel based codelivery systems could potentially be a promising candidate for controlled drug delivery systems. PMID:26851440

  10. Brownian particles in supramolecular polymer solutions

    OpenAIRE

    Gucht, van der, J.; Besseling, N.A.M.; Knoben, W.; Bouteiller, L; Cohen Stuart, M. A.

    2003-01-01

    The Brownian motion of colloidal particles embedded in solutions of hydrogen-bonded supramolecular polymers has been studied using dynamic light scattering. At short times, the motion of the probe particles is diffusive with a diffusion coefficient equal to that in pure solvent. At intermediate time scales the particles are slowed down as a result of trapping in elastic cages formed by the polymer chains, while at longer times the motion is diffusive again, but with a much smaller diffusion c...

  11. Coordination Supramolecular Chemistry and Crystal Engineering

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Consisting of five young researchers from the Sun Yat-Sen University in Guangzhou, the research group has been devoted to the interdisciplinary research in chemistry, materials science and chemical biology.To be specific, the focus of their research is to develop new functional molecular materials through rational molecular design and crystal engineering, including porous materials (or porous coordination polymers), electronic and magnetic molecular materials, bio-mimic materials, and supramolecular catalytical materials.

  12. Prion-like nanofibrils of small molecules (PriSM): A new frontier at the intersection of supramolecular chemistry and cell biology.

    Science.gov (United States)

    Zhou, Jie; Du, Xuewen; Xu, Bing

    2015-01-01

    Formed by non-covalent interactions and not defined at genetic level, the assemblies of small molecules in biology are complicated and less explored. A common morphology of the supramolecular assemblies of small molecules is nanofibrils, which coincidentally resembles the nanofibrils formed by proteins such as prions. So these supramolecular assemblies are termed as prion-like nanofibrils of small molecules (PriSM). Emerging evidence from several unrelated fields over the past decade implies the significance of PriSM in biology and medicine. This perspective aims to highlight some recent advances of the research on PriSM. This paper starts with description of the intriguing similarities between PriSM and prions, discusses the paradoxical features of PriSM, introduces the methods for elucidating the biological functions of PriSM, illustrates several examples of beneficial aspects of PriSM, and finishes with the promises and current challenges in the research of PriSM. We anticipate that the research of PriSM will contribute to the fundamental understanding at the intersection of supramolecular chemistry and cell biology and ultimately lead to a new paradigm of molecular (or supramolecular) therapeutics for biomedicine.

  13. Self and directed assembly: people and molecules.

    Science.gov (United States)

    James, Tony D

    2016-01-01

    Self-assembly and directed-assembly are two very important aspects of supramolecular chemistry. As a young postgraduate student working in Canada with Tom Fyles my introduction to Supramolecular Chemistry was through the self-assembly of phospholipid membranes to form vesicles for which we were developing unimolecular and self-assembling transporter molecules. The next stage of my development as a scientist was in Japan with Seiji Shinkai where in a "Eureka" moment, the boronic acid templating unit (directed-assembly) of Wulff was combined with photoinduced electron transfer systems pioneered by De Silva. The result was a turn-on fluorescence sensor for saccharides; this simple result has continued to fuel my research to the present day. Throughout my career as well as assembling molecules, I have enjoyed bringing together researchers in order to develop collaborative networks. This is where molecules meet people resulting in assemblies worth more than the individual "molecule" or "researcher". My role in developing networks with Japan was rewarded by the award of a Daiwa-Adrian Prize in 2013 and I was recently rewarded for developing networks with China with an Inaugural CASE Prize in 2015. PMID:27340435

  14. From coordination polymers to hierarchical self-assembled structures

    NARCIS (Netherlands)

    Yan, Y.; Keizer, de A.; Cohen Stuart, M.A.; Besseling, N.A.M.

    2011-01-01

    In this review, novel hierarchical self-assembled structures based on reversible organo-metallic supramolecular polymers are discussed. Firstly, we discuss recent advances in the field of coordination polymers, considering cases in which transition metal ions and bis- or multiligands are used to bui

  15. The thermodynamics of the self-assembly of covalently linked oligomeric naphthalenediimides into helical organic nanotubes.

    Science.gov (United States)

    Tambara, Koujiro; Olsen, John-Carl; Hansen, David E; Pantoş, G Dan

    2014-01-28

    The mechanism and thermodynamic functions of the self-assembly of a family of covalently linked oligomeric naphthalenediimides (NDIs) were investigated through variable-temperature NMR and CD studies. The NDIs were shown to self-assemble into helical supramolecular nanotubes via an isodesmic polymerisation mechanism, and regardless of the oligomer length a surprising entropy-enthalpy compensation was observed. PMID:24287562

  16. Sustained and controlled release of lipophilic drugs from a self-assembling amphiphilic peptide hydrogel

    DEFF Research Database (Denmark)

    Briuglia, Maria-Lucia; Urquhart, Andrew; Lamprou, Dimitrios A.

    2014-01-01

    Materials which undergo self-assembly to form supramolecular structures can provide alternative strategies to drug loading problems in controlled release application. RADA 16 is a simple and versatile self-assembling peptide with a designed structure formed of two distinct surfaces, one hydrophilic...

  17. Selective assemblies of giant tetrahedra via precisely controlled positional interactions

    Science.gov (United States)

    Huang, Mingjun; Hsu, Chih-Hao; Wang, Jing; Mei, Shan; Dong, Xuehui; Li, Yiwen; Li, Mingxuan; Liu, Hao; Zhang, Wei; Aida, Takuzo; Zhang, Wen-Bin; Yue, Kan; Cheng, Stephen Z. D.

    2015-04-01

    Self-assembly of rigid building blocks with explicit shape and symmetry is substantially influenced by the geometric factors and remains largely unexplored. We report the selective assembly behaviors of a class of precisely defined, nanosized giant tetrahedra constructed by placing different polyhedral oligomeric silsesquioxane (POSS) molecular nanoparticles at the vertices of a rigid tetrahedral framework. Designed symmetry breaking of these giant tetrahedra introduces precise positional interactions and results in diverse selectively assembled, highly ordered supramolecular lattices including a Frank-Kasper A15 phase, which resembles the essential structural features of certain metal alloys but at a larger length scale. These results demonstrate the power of persistent molecular geometry with balanced enthalpy and entropy in creating thermodynamically stable supramolecular lattices with properties distinct from those of other self-assembling soft materials.

  18. Porphyrin Diacid-Polyelectrolyte Assemblies: Effective Photocatalysts in Solution

    Directory of Open Access Journals (Sweden)

    Sabine Frühbeißer

    2016-05-01

    Full Text Available Developing effective and versatile photocatalytic systems is of great potential in solar energy conversion. Here we investigate the formation of supramolecular catalysts by electrostatic self-assembly in aqueous solution: Combining positively charged porphyrins with negatively charged polyelectrolytes leads to nanoscale assemblies where, next to electrostatic interactions, π–π interactions also play an important role. Porphyrin diacid-polyelectrolyte assemblies exhibit a substantially enhanced catalytic activity for the light-driven oxidation of iodide. Aggregates with the hexavalent cationic porphyrin diacids show up to 22 times higher catalytic activity than the corresponding aggregates under neutral conditions. The catalytic activity can be increased by increasing the valency of the porphyrin and by choice of the loading ratio. The structural investigation of the supramolecular catalysts took place via atomic force microscopy and small angle neutron scattering. Hence, a new facile concept for the design of efficient and tunable self-assembled photocatalysts is presented.

  19. Amorphous supramolecular structure of carboxymethyl cellulose in aqueous solution at different pH values as determined by rheology, small angle X-ray and light scattering.

    Science.gov (United States)

    Dogsa, Iztok; Tomšič, Matija; Orehek, Janez; Benigar, Elizabeta; Jamnik, Andrej; Stopar, David

    2014-10-13

    Carboxymethyl cellulose (CMC) is one of the most widely used thickening agents in industry. The combination of small-angle X-ray scattering (SAXS), static and dynamic light scattering, as well as viscosity measurements and microscopy at different pH values was utilized to explore the physicochemical properties of CMC on a scale ranging from individual macromolecules to supramolecular assemblies. The supramolecular structure of CMC was represented as a set of characteristic sample subspaces based on SAXS data utilizing the string-of-beads model. The results indicate that at pH 7.0 individual CMC molecules are approximately uniformly distributed in a supramolecular structure owing to strong intra- and intermolecular repulsive interactions. The structure of CMC is most expanded at the value of pKa, where it has the largest radius of gyration, persistence length, and size of heterogeneous regions. Below pKa the majority of the CMC sample volume belongs to the low density subspaces. Most of CMC molecules, however, reside in a few high density subspaces. Dynamically, supramolecular structure of CMC is composed of fast diffusive relaxation processes embedded in a background of non-diffusive slow relaxation process at high pH and mostly slow relaxation processes at low pH. The rheological properties of CMC at different pH values were directly related to the CMC supramolecular structure in the aqueous environment. PMID:25037380

  20. Biomimetic supramolecular metallohosts for binding and activation of dioxygen

    NARCIS (Netherlands)

    Sprakel, Vera Stefanie Irene

    2004-01-01

    Host-guest chemistry involves the binding of a specific substrate in a receptor via molecular recognition based on supramolecular interactions. Metal-containing derivatives of receptors for the selective supramolecular binding of dihydroxybenzene substrates, which receptors model oxygen binding enz

  1. Supramolecular biomaterials. A modular approach towards tissue engineering

    NARCIS (Netherlands)

    Dankers, Patricia Y. W.; Meijer, E. W.

    2007-01-01

    Supramolecular chemistry is an exciting area of science that plays a central role in bringing different disciplines together, ranging from molecular medicine to nanotechnology. Materials science based on supramolecular interactions is an emerging field, which has made important steps forward in the

  2. Supramolecular Photochemistry as a Potential Synthetic Tool: Photocycloaddition.

    Science.gov (United States)

    Ramamurthy, Vaidhyanathan; Sivaguru, Jayaraman

    2016-09-14

    Photochemistry, bearing significant applications in natural and man-made events such as photosynthesis, vision, photolithography, photodynamic therapy, etc., is yet to become a common tool during the synthesis of small molecules in a laboratory. Among other rationale, the inability to influence photochemical reactions with temperature, solvent, additives, etc., dissuades chemists from employing light-initiated reactions as a routine synthetic tool. This review highlights how diverse, highly organized structures such as solvent-free crystals and water-soluble host-guest assemblies can be employed to control and manipulate photoreactions and thereby serve as an efficient tool for chemists, including those interested in synthesis. The efficacy of the media in modifying the excited-state behavior of organic molecules is illustrated with photocycloaddition in general and [2 + 2] photocycloaddition in particular, reactions widely employed in the synthesis of complex natural products as well as highly constrained molecules, as exemplars. The reaction media, highly pertinent in the context of green sustainable chemistry, include solvent-free crystals and solids such as silica, clay, and zeolite and water-soluble hosts that can solubilize and preorganize hydrophobic reactants in water. Since no other reagent would be more sustainable than light and no other medium greener than water, we believe that the supramolecular photochemistry expounded here has a momentous role as a synthetic tool in the future.

  3. Mesoscopic Self-Assembly: A Shift to Complexity

    Directory of Open Access Journals (Sweden)

    Massimo eMastrangeli

    2015-06-01

    Full Text Available By focusing on the construction of thermodynamically stable structures, the self-assembly of mesoscopic systems has proven capable of formidable achievements in the bottom-up engineering of micro- and nanosystems. Yet, inspired by an analogous evolution in supramolecular chemistry, synthetic mesoscopic self-assembly may have a lot more ahead, within reach of a shift toward fully three-dimensional architectures, collective interactions of building blocks and kinetic control. All over these challenging fronts, complexity holds the key.

  4. Supramolecular liquid-crystal gels formed by polyfluorene-based π-conjugated polymer for switchable anisotropic scattering device.

    Science.gov (United States)

    Chen, Jun-Wei; Huang, Chiu-Chang; Chao, Chih-Yu

    2014-05-14

    To overcome the problem of high driving voltage and low contrast ratio in the switchable scattering device of conventional liquid-crystal (LC) physical gel, a new type of supramolecular LC physical gel has been developed and fabricated through the fibrous self-assembly of the polyfluorene-based π-conjugated polymer, poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT), in nematic LC mixture E7. It was found that the rubbed interface between the LC molecules and polyimide layer can induce the LC physical gels to demonstrate fantastic light scattering characteristic. The gels with oriented self-assembled supramolecular structures exhibiting significant anisotropic light scattering in the main-chain direction of the F8BT molecules under an extremely low driving voltage (ca. 2.7 V) are reported for the first time. In addition, the contrast ratio can be reached exceeding 1000. In contrast to conventional LC physical gels, the large reduction of driving voltages of the supramolecular gel provides great possibility for application in various electro-optical devices such as tunable polarizers, transflective displays, and polarized light modulators. PMID:24724859

  5. Cholesterol-tethered platinum II-based supramolecular nanoparticle increases antitumor efficacy and reduces nephrotoxicity.

    Science.gov (United States)

    Sengupta, Poulomi; Basu, Sudipta; Soni, Shivani; Pandey, Ambarish; Roy, Bhaskar; Oh, Michael S; Chin, Kenneth T; Paraskar, Abhimanyu S; Sarangi, Sasmit; Connor, Yamicia; Sabbisetti, Venkata S; Kopparam, Jawahar; Kulkarni, Ashish; Muto, Katherine; Amarasiriwardena, Chitra; Jayawardene, Innocent; Lupoli, Nicola; Dinulescu, Daniela M; Bonventre, Joseph V; Mashelkar, Raghunath A; Sengupta, Shiladitya

    2012-07-10

    Nanoscale drug delivery vehicles have been harnessed extensively as carriers for cancer chemotherapeutics. However, traditional pharmaceutical approaches for nanoformulation have been a challenge with molecules that exhibit incompatible physicochemical properties, such as platinum-based chemotherapeutics. Here we propose a paradigm based on rational design of active molecules that facilitate supramolecular assembly in the nanoscale dimension. Using cisplatin as a template, we describe the synthesis of a unique platinum (II) tethered to a cholesterol backbone via a unique monocarboxylato and O→Pt coordination environment that facilitates nanoparticle assembly with a fixed ratio of phosphatidylcholine and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino (polyethylene glycol)-2000]. The nanoparticles formed exhibit lower IC(50) values compared with carboplatin or cisplatin in vitro, and are active in cisplatin-resistant conditions. Additionally, the nanoparticles exhibit significantly enhanced in vivo antitumor efficacy in murine 4T1 breast cancer and in K-Ras(LSL/+)/Pten(fl/fl) ovarian cancer models with decreased systemic- and nephro-toxicity. Our results indicate that integrating rational drug design and supramolecular nanochemistry can emerge as a powerful strategy for drug development. Furthermore, given that platinum-based chemotherapeutics form the frontline therapy for a broad range of cancers, the increased efficacy and toxicity profile indicate the constructed nanostructure could translate into a next-generation platinum-based agent in the clinics.

  6. A Supramolecular Sensing Platform for Phosphate Anions and an Anthrax Biomarker in a Microfluidic Device

    Directory of Open Access Journals (Sweden)

    Jurriaan Huskens

    2011-10-01

    Full Text Available A supramolecular platform based on self-assembled monolayers (SAMs has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detection. A Eu(III-EDTA complex was bound to β-cyclodextrin monolayers via orthogonal supramolecular host-guest interactions. The self-assembly of the Eu(III-EDTA conjugate and naphthalene β-diketone as an antenna resulted in the formation of a highly luminescent lanthanide complex on the microchannel surface. Detection of different phosphate anions and aromatic carboxylic acids was demonstrated by monitoring the decrease in red emission following displacement of the antenna by the analyte. Among these analytes, adenosine triphosphate (ATP and pyrophosphate, as well as dipicolinic acid (DPA which is a biomarker for anthrax, showed a strong response. Parallel fabrication of five sensing SAMs in a single multichannel chip was performed, as a first demonstration of phosphate and carboxylic acid screening in a multiplexed format that allows a general detection platform for both analyte systems in a single test run with µM and nM detection sensitivity for ATP and DPA, respectively.

  7. 基于冠醚衍生物的超分子聚合物%SUPRAMOLECULAR POLYMERS BASED ON CROWN ETHER DERIVATIVES

    Institute of Scientific and Technical Information of China (English)

    汪峰; 董盛谊; 郑波; 黄飞鹤

    2011-01-01

    自组装现象是生命科学最本质的内容之一,生物体系可以精确地利用非共价键相互作用形成高度有序的功能组装体.受到大自然的启发,近年来利用分子自组装构筑包括超分子聚合物在内的有序聚集体是超分子科学的研究热点.此类组装体不仅在拓扑学上具有重要的意义,而且可以用来制备动态的超分子功能材料.冠醚作为第一代超分子主体化合物,由于其结构简单、易于衍生化,且与多种正离子具有选择性络合作用,越来越广泛地被用作为超分子组装体的构筑单元.本文综述了近年来基于冠醚衍生物超分子聚合物方面的研究.%Self-assembly is ubiquitous in nature. Biological systems utilize nonocovalent forces to control the self-assembly process precisely, resulting in the formation of complicated structures with multiple functions. Inspired by the structure of biological macromolecules, chemists are engaged in developing highly-ordered artificial supramolecular assemblies such as supramolecular polymers, which exhibit great significance in the formation of various supramolecular architectures, and more importantly, the potential applications of dynamic supramolecular materials. In recent years more and more attentions have been paid to crown ethers,one of the most commonly used hosts in supramolecular chemistry, which serve as the building blocks to construct functional supramolecular assemblies due to their facilitated syntheses, convenient structure modification and unique complexation properties with a variety of guest molecules. This review focuses on supramolecular polymers based on crown ether derivatives.

  8. Two-dimensional pentacene:3,4,9,10-perylenetetracarboxylic dianhydride supramolecular chiral networks on Ag(111).

    Science.gov (United States)

    Chen, Wei; Li, Hui; Huang, Han; Fu, Yuanxi; Zhang, Hong Liang; Ma, Jing; Wee, Andrew Thye Shen

    2008-09-17

    Self-assembly of the binary molecular system of pentacene and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on Ag(111) has been investigated by low-temperature scanning tunneling microscopy, molecular dynamics (MD), and density functional theory (DFT) calculations. Well-ordered two-dimensional (2D) pentacene:PTCDA supramolecular chiral networks are observed to form on Ag(111). The 2D chiral network formation is controlled by the strong interfacial interaction between adsorbed molecules and the underlying Ag(111), as revealed by MD and DFT calculations. The registry effect locks the adsorbed pentacene and PTCDA molecules into specific adsorption sites due to the corrugation of the potential energy surface. The 2D supramolecular networks are further constrained through the directional CO...H-C multiple intermolecular hydrogen bonding between the anhydride groups of PTCDA and the peripheral aromatic hydrogen atoms of the neighboring pentacene molecules. PMID:18722423

  9. Room temperature supramolecular columnar liquid crystals formed by hydrogen bonding of isoquinoline derivatives

    Science.gov (United States)

    Hyup Lee, Jun; Lee, Seung Jun; Jho, Jae Young

    2014-07-01

    We report new self-assembled discotic liquid crystals exhibiting columnar mesophases at room temperature, which are constructed by intermolecular hydrogen bonding between the core of 1,3,5-trihydroxybenzene or 1,3,5-cyclohexanetricarboxylic acid and the peripheral molecules of isoquinoline derivatives. The mesomorphic properties of supramolecular liquid crystals were investigated by differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction studies. The self-assembled liquid crystals exhibited rectangular columnar phases (Colro) with an ordered stacking structure of the mesogens in a column at room temperature, regardless of the type of the core molecule, due probably to the close-packed aromatic rings around a core molecule and the angular structure in three arms of the discotic mesogen. These room temperature columnar phases are rare examples for the discotic liquid crystals, and our findings in the present study provide a new way to prepare low melting columnar liquid crystalline materials for molecular electronics.

  10. Exploring new avenues for Arene-Ruthenium complexes: coordination to [60]fullerene, hydrogen bonding assemblies and liquid-crystalline materials

    OpenAIRE

    Appavoo-Gupta, Divambal; Deschenaux, Robert

    2016-01-01

    The thesis aims at using arene-ruthenium complexes as building blocks for the synthesis of diverse compounds to obtain potential mesomorphic and/or biological properties. The thesis consists of three main projects. The first project deals with supramolecular assemblies. New supramolecular di- and tetranuclear ruthenium arrangements, the latter bearing a cavity, were designed. H-bonding was the key interaction involved in the synthesis of the spacer ligands, which exist as dimers. Different s...

  11. Tailoring Supramolecular Nanofibers for Air Filtration Applications.

    Science.gov (United States)

    Weiss, Daniel; Skrybeck, Dominik; Misslitz, Holger; Nardini, David; Kern, Alexander; Kreger, Klaus; Schmidt, Hans-Werner

    2016-06-15

    The demand of new materials and processes for nanofiber fabrication to enhance the performance of air filters is steadily increasing. Typical approaches to obtain nanofibers are based on top-down processes such as melt blowing, centrifugal spinning, and electrospinning of polymer materials. However, fabrication of polymer nanofibers is limited with respect to either a sufficiently high throughput or the smallest achievable fiber diameter. This study reports comprehensively on a fast and simple bottom-up process to prepare supramolecular nanofibers in situ inside viscose/polyester microfiber nonwovens. Here, selected small molecules of the materials class of 1,3,5-benzenetrisamides are employed. The microfiber-nanofiber composites exhibit a homogeneous nanofiber distribution and morphology throughout the entire nonwoven scaffold. Small changes in molecular structure and processing solvent have a strong influence on the final nanofiber diameter and diameter distribution and, consequently, on the filtration performance. Choosing proper processing conditions, microfiber-nanofiber composites with surprisingly high filtration efficiencies of particulate matter are obtained. In addition, the microfiber-nanofiber composite integrity at elevated temperatures was determined and revealed that the morphology of supramolecular nanofibers is maintained compared to that of the utilized polymer nonwoven. PMID:27183242

  12. Cellular uptake: lessons from supramolecular organic chemistry.

    Science.gov (United States)

    Gasparini, Giulio; Bang, Eun-Kyoung; Montenegro, Javier; Matile, Stefan

    2015-07-01

    The objective of this Feature Article is to reflect on the importance of established and emerging principles of supramolecular organic chemistry to address one of the most persistent problems in life sciences. The main topic is dynamic covalent chemistry on cell surfaces, particularly disulfide exchange for thiol-mediated uptake. Examples of boronate and hydrazone exchange are added for contrast, comparison and completion. Of equal importance are the discussions of proximity effects in polyions and counterion hopping, and more recent highlights on ring tension and ion pair-π interactions. These lessons from supramolecular organic chemistry apply to cell-penetrating peptides, particularly the origin of "arginine magic" and the "pyrenebutyrate trick," and the currently emerging complementary "disulfide magic" with cell-penetrating poly(disulfide)s. They further extend to the voltage gating of neuronal potassium channels, gene transfection, and the delivery of siRNA. The collected examples illustrate that the input from conceptually innovative chemistry is essential to address the true challenges in biology beyond incremental progress and random screening.

  13. Advantages of Catalysis in Self-Assembled Molecular Capsules.

    Science.gov (United States)

    Catti, Lorenzo; Zhang, Qi; Tiefenbacher, Konrad

    2016-06-27

    Control over the local chemical environment of a molecule can be achieved by encapsulation in supramolecular host systems. In supramolecular catalysis, this control is used to gain advantages over classical homogeneous catalysis in bulk solution. Two of the main advantages concern influencing reactions in terms of substrate and product selectivity. Due to size and/or shape recognition, substrate selective conversion can be realized. Additionally, noncovalent interactions with the host environment facilitate alternative reaction pathways and can yield unusual products. This Concept article discusses and highlights literature examples utilizing self-assembled molecular capsules to achieve catalytic transformations displaying a high degree of substrate and/or product selectivity. Furthermore, the advantage of supramolecular hosts in multicatalyst tandem reactions is covered. PMID:27150251

  14. Supramolecular Soft Matter Applications in Materials and Organic Electronics

    CERN Document Server

    Nakanishi, Takashi

    2011-01-01

    The pivotal text that bridges the gap between fundamentals and applications of soft matter in organic electronics Covering an expanding and highly coveted subject area, Supramolecular Soft Matter enlists the services of leading researchers to help readers understand and manipulate the electronic properties of supramolecular soft materials for use in organic opto-electronic devices, such as photovoltaics and field effect transistors, some of the most desired materials for energy conservation. Rather than offering a compilation of current trends in supramolecular soft matter, this book bridges

  15. Controlling the Physical Dimensions of Peptide Nanotubes by Supramolecular Polymer Coassembly.

    Science.gov (United States)

    Adler-Abramovich, Lihi; Marco, Pini; Arnon, Zohar A; Creasey, Rhiannon C G; Michaels, Thomas C T; Levin, Aviad; Scurr, David J; Roberts, Clive J; Knowles, Tuomas P J; Tendler, Saul J B; Gazit, Ehud

    2016-08-23

    Molecular self-assembly of peptides into ordered nanotubes is highly important for various technological applications. Very short peptide building blocks, as short as dipeptides, can form assemblies with unique mechanical, optical, piezoelectric, and semiconductive properties. Yet, the control over nanotube length in solution has remained challenging, due to the inherent sequential self-assembly mechanism. Here, in line with polymer chemistry paradigms, we applied a supramolecular polymer coassembly methodology to modulate peptide nanotube elongation. Utilizing this approach, we achieved a narrow, controllable nanotube length distribution by adjusting the molecular ratio of the diphenylalanine assembly unit and its end-capped analogue. Kinetic analysis suggested a slower coassembly organization process as compared to the self-assembly dynamics of each of the building blocks separately. This is consistent with a hierarchal arrangement of the peptide moieties within the coassemblies. Mass spectrometry analysis demonstrated the bimolecular composition of the coassembled nanostructures. Moreover, the peptide nanotubes' length distribution, as determined by electron microscopy, was shown to fit a fragmentation kinetics model. Our results reveal a simple and efficient mechanism for the control of nanotube sizes through the coassembly of peptide entities at various ratios, allowing for the desired end-product formation. This dynamic size control offers tools for molecular engineering at the nanoscale exploiting the advantages of molecular coassembly.

  16. Expression and cytosolic assembly of the S-layer fusion protein mSbsC-EGFP in eukaryotic cells

    NARCIS (Netherlands)

    Blecha, Andreas; Zarschler, Kristof; Sjollema, Klaas A.; Veenhuis, Marten; Rödel, Gerhard; Rodel, G.

    2005-01-01

    Background: Native as well as recombinant bacterial cell surface layer (S-layer) protein of Geobacillus (G.) stearothermophilus ATCC 12980 assembles to supramolecular structures with an oblique symmetry. Upon expression in E. coli, S-layer self assembly products are formed in the cytosol. We tested

  17. Multi-hierarchical self-assembly of a collagen mimetic peptide from triple helix to nanofibre and hydrogel

    Science.gov (United States)

    Replicating the multi-hierarchical self-assembly of collagen has long-attracted scientists, from both the perspective of the fundamental science of supramolecular chemistry and that of potential biomedical applications in tissue engineering. Many approaches to drive the self-assembly of synthetic s...

  18. Synthesis and Characterization of thermo/pH-responsive Supramolecular G-Quadruplexes for the Construction of Supramolecular Hacky Sacks for Biorelevant Applications

    Science.gov (United States)

    Negron Rios, Luis M.

    The impact of size, shape, and distribution of lipophilic regions on the surfaces of nanoscopic objects that are amphiphilic or patchy (such as proteins) are yet to be fully understood. One of the reasons for this is the lack of an appropriate model systems in which to probe this question. Our group has previously reported 2'-deoxyguanosine (8ArG) derivatives that self-assemble in aqueous media into discrete supramolecular hexadecamers that show the lower critical solution temperature (LCST) phenomenon. The LCST phenomenon is a convenient and rigorous strategy to measure the hydrophobicity of a system. Although these SGQs are potentially attractive for biomedical applications like drug-delivery, the narrow window of physiological temperatures complicates their implementation. This moved us to redesign the constituent 8ArG subunits to incorporate imidazole moieties that would lead to pH-responsive SGQs, working isothermally. Upon reaching a threshold temperature (Lower Critical Solution Temperature, LCST) at pH 7, these dual-responsive SGQs further self-assemble to form nano/micro hydrogel globules that we called them supramolecular hacky sacks (SHS). However, we can isolate kinetically stable versions of these SHS by lowering the ionic strength of the medium (i.e., from the molar to the millimolar range) in a process that we term "fixing the SHS", in which these SHS maintain their integrity (size and shape) and stability without the requirement of crosslinking agents. After structural characterization and in vitro studies of SHS, we performed encapsulation studies of DOX, rhodamine, dsDNA (F26T), thrombin binding aptamer (TBA) and dextran (3 kDa) Texas Red conjugate. Then we performed in vivo studies of cell internalization and drug delivery with neuroblastoma SY-SH5Y. The performed studies will bring new approaches for the development of new biotechnology for fundamental applications and the emerging of novel therapeutic agents for biomedical applications.

  19. Programming supramolecular biohybrids as precision therapeutics.

    Science.gov (United States)

    Ng, David Yuen Wah; Wu, Yuzhou; Kuan, Seah Ling; Weil, Tanja

    2014-12-16

    CONSPECTUS: Chemical programming of macromolecular structures to instill a set of defined chemical properties designed to behave in a sequential and precise manner is a characteristic vision for creating next generation nanomaterials. In this context, biopolymers such as proteins and nucleic acids provide an attractive platform for the integration of complex chemical design due to their sequence specificity and geometric definition, which allows accurate translation of chemical functionalities to biological activity. Coupled with the advent of amino acid specific modification techniques, "programmable" areas of a protein chain become exclusively available for any synthetic customization. We envision that chemically reprogrammed hybrid proteins will bridge the vital link to overcome the limitations of synthetic and biological materials, providing a unique strategy for tailoring precision therapeutics. In this Account, we present our work toward the chemical design of protein- derived hybrid polymers and their supramolecular responsiveness, while summarizing their impact and the advancement in biomedicine. Proteins, in their native form, represent the central framework of all biological processes and are an unrivaled class of macromolecular drugs with immense specificity. Nonetheless, the route of administration of protein therapeutics is often vastly different from Nature's biosynthesis. Therefore, it is imperative to chemically reprogram these biopolymers to direct their entry and activity toward the designated target. As a consequence of the innate structural regularity of proteins, we show that supramolecular interactions facilitated by stimulus responsive chemistry can be intricately designed as a powerful tool to customize their functions, stability, activity profiles, and transportation capabilities. From another perspective, a protein in its denatured, unfolded form serves as a monodispersed, biodegradable polymer scaffold decorated with functional side

  20. COST : action chemistry conference on supramolecular chemistry in water

    OpenAIRE

    Magri, David C.

    2014-01-01

    Scientists and chemists from 18 countries gathered in Malta for the 3rd Scientific Meeting on Supramolecular Chemistry in Water between the 9 − 11th of November 2013 at the Old University Building on St Paul Street in Valletta

  1. Magnetic structure of two- and three-dimensional supramolecular compounds

    Energy Technology Data Exchange (ETDEWEB)

    Decurtins, S.; Schmalle, H.W.; Pellaux, R. [Zurich Univ. (Switzerland); Fischer, P.; Fauth, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ouladdiaf, B. [Institut Max von Laue - Paul Langevin, 75 - Paris (France)

    1997-09-01

    Supramolecular chiral networks of oxalato-bridged transition metals show either two- or three-dimensional structural features. The magnetic structures of such compounds have been investigated by means of elastic neutron powder diffraction. (author) 2 figs., 2 refs.

  2. Biomimetic supramolecular metallohosts for binding and activation of dioxygen

    OpenAIRE

    Sprakel, Vera Stefanie Irene

    2004-01-01

    Host-guest chemistry involves the binding of a specific substrate in a receptor via molecular recognition based on supramolecular interactions. Metal-containing derivatives of receptors for the selective supramolecular binding of dihydroxybenzene substrates, which receptors model oxygen binding enzymes both in structure and in function are described in this thesis with the ultimate goal to realize biomimetic catalysis. A PY2-appended receptor 1 and a TPA-appended receptor 2 and the bis-copper...

  3. Physical crosslinking of gelatin : a supramolecular approach to biomaterials

    OpenAIRE

    Zaupa, Alessandro

    2011-01-01

    This work describes the realization of physically crosslinked networks based on gelatin by the introduction of functional groups enabling specific supramolecular interactions. Molecular models were developed in order to predict the material properties and permit to establish a knowledge-based approach to material design. The effect of additional supramolecular interactions with hydroxyapaptite was then studied in composite materials. The calculated properties are compared to experimental resu...

  4. Supramolecular ionic liquid based on graphene oxide.

    Science.gov (United States)

    Zeng, Chunfang; Tang, Zhenghai; Guo, Baochun; Zhang, Liqun

    2012-07-28

    For the purpose of preparing liquefied graphene oxide (GO), a process consisting of sulfonation with sodium sulfanilic acid and ionization with bulky amine-terminated Jeffamine® was designed and performed. The obtained hybrid fluid is actually a supramolecular ionic liquid (SIL) with sulfonated GO as the central anions and the terminal ammonium groups of Jeffamine® as the surrounding cations. The successful grafting of the GO sheets with Jeffamine®via an ionic structure was verified and the morphology of the SIL was characterized. The SIL based on GO (GO-SIL) exhibits excellent solubility and amphiphilicity. The rheological measurements confirm the essential viscoelasticity and the liquid-like behavior of GO-SIL. The present GO based SIL suggests promising applications in the fabrication of various GO or graphene based composite materials. In addition, the new functionalization method may guide the future work on acquiring derivatives with tunable properties by simply changing the bulky canopy.

  5. Supramolecular Tectonics for Enzyme-like Reagents

    Institute of Scientific and Technical Information of China (English)

    MAO; LuYuan

    2001-01-01

    The enzyme-likes and bioactive species were closely related with the life phenomena and served as the reagent of bioassy1,2. In present works, the flow cytometry (FCM) and rapid-scanning stopped-flow (RSSF) spectroscopy combine with the stopped-flow difference UV/Vis spectra, FT-IR and other methods of assay, being used to study the biomimetic reaction and enzyme mimic. Based on catalytic kinetics of enzyme reaction3,4, the reaction mechanisms of the enzyme-likes had been studied and some new methods of kinetic determination were proposed. The study and methods not only provided the basic theoretical models for the life science, but also widened the application fields of biomimetic and analytical chemistry. The main contents of our works and the supramolecular models can be described as follows:  ……

  6. Versatile supramolecular reactivity of zinc-tetra(4-pyridylporphyrin in crystalline solids: Polymeric grids with zinc dichloride and hydrogen-bonded networks with mellitic acid

    Directory of Open Access Journals (Sweden)

    Sophia Lipstman

    2009-12-01

    Full Text Available Crystal engineering studies confirm that the zinc-tetra(4-pyridylporphyrin building block reveals versatile supramolecular chemistry. In this work, it was found to be reactive in the assembly of both (a a 2D polymeric array by a unique combination of self-coordination and coordination through external zinc dichloride linkers and (b an extended heteromolecular hydrogen-bonded network with mellitic acid sustained by multiple connectivity between the component species.

  7. Biomineralization of a Self-assembled, Soft-Matrix Precursor: Enamel

    Science.gov (United States)

    Snead, Malcolm L.

    2015-04-01

    Enamel is the bioceramic covering of teeth, a composite tissue composed of hierarchical organized hydroxyapatite crystallites fabricated by cells under physiologic pH and temperature. Enamel material properties resist wear and fracture to serve a lifetime of chewing. Understanding the cellular and molecular mechanisms for enamel formation may allow a biology-inspired approach to material fabrication based on self-assembling proteins that control form and function. A genetic understanding of human diseases exposes insight from nature's errors by exposing critical fabrication events that can be validated experimentally and duplicated in mice using genetic engineering to phenocopy the human disease so that it can be explored in detail. This approach led to an assessment of amelogenin protein self-assembly that, when altered, disrupts fabrication of the soft enamel protein matrix. A misassembled protein matrix precursor results in loss of cell-to-matrix contacts essential to fabrication and mineralization.

  8. Injectable micellar supramolecular hydrogel for delivery of hydrophobic anticancer drugs.

    Science.gov (United States)

    Fu, CuiXiang; Lin, XiaoXiao; Wang, Jun; Zheng, XiaoQun; Li, XingYi; Lin, ZhengFeng; Lin, GuangYong

    2016-04-01

    In this paper, an injectable micellar supramolecular hydrogel composed of α-cyclodextrin (α-CD) and monomethoxy poly(ethylene glycol)-b-poly(ε-caplactone) (MPEG5000-PCL5000) micelles was developed by a simple method for hydrophobic anticancer drug delivery. By mixing α-CD aqueous solution and MPEG5000-PCL5000 micelles, an injectable micellar supramolecular hydrogel could be formed under mild condition due to the inclusion complexation between α-CD and MPEG segment of MPEG5000-PCL5000 micelles. The resultant supramolecular hydrogel was thereafter characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The effect of α-CD amount on the gelation time, mechanical strength and thixotropic property was studied by a rheometer. Payload of hydrophobic paclitaxel (PTX) to supramolecular hydrogel was achieved by encapsulation of PTX into MPEG5000-PCL5000 micelles prior mixing with α-CD aqueous solution. In vitro release study showed that the release behavior of PTX from hydrogel could be modulated by change the α-CD amount in hydrogel. Furthermore, such supramolecular hydrogel could enhance the biological activity of encapsulated PTX compared to free PTX, as indicated by in vitro cytotoxicity assay. All these results indicated that the developed micellar supramolecular hydrogel might be a promising injectable drug delivery system for anticancer therapy. PMID:26886821

  9. Multispecies population dynamics of prebiotic compositional assemblies.

    Science.gov (United States)

    Markovitch, Omer; Lancet, Doron

    2014-09-21

    Present life portrays a two-tier phenomenology: molecules compose supramolecular structures, such as cells or organisms, which in turn portray population behaviors, including selection, evolution and ecological dynamics. Prebiotic models have often focused on evolution in populations of self-replicating molecules, without explicitly invoking the intermediate molecular-to-supramolecular transition. Here, we explore a prebiotic model that allows one to relate parameters of chemical interaction networks within molecular assemblies to emergent population dynamics. We use the graded autocatalysis replication domain (GARD) model, which simulates the network dynamics within amphiphile-containing molecular assemblies, and exhibits quasi-stationary compositional states termed compotype species. These grow by catalyzed accretion, divide and propagate their compositional information to progeny in a replication-like manner. The model allows us to ask how molecular network parameters influence assembly evolution and population dynamics parameters. In 1000 computer simulations, each embodying different parameter set of the global chemical interaction network parameters, we observed a wide range of behaviors. These were analyzed by a multi species logistic model often used for analyzing population ecology (r-K or Lotka-Volterra competition model). We found that compotypes with a larger intrinsic molecular repertoire show a higher intrinsic growth (r) and lower carrying capacity (K), as well as lower replication fidelity. This supports a prebiotic scenario initiated by fast-replicating assemblies with a high molecular diversity, evolving into more faithful replicators with narrower molecular repertoires. PMID:24831416

  10. Electrochemical aptasensor for highly sensitive determination of cocaine using a supramolecular aptamer and rolling circle amplification

    International Nuclear Information System (INIS)

    We report on a novel strategy for the electrochemical detection of cocaine. It is based on the use of a supramolecular aptamer, rolling circle amplification (RCA), and multiplex binding of a biotin-strepavidin system. The aptamer fragments were assembled to a supramolecular aptamer which, in the presence of cocaine, conjugates to streptavidin for anchoring of biotinylated circular DNA. This initiates RCA and enables sensitive electrochemical-enzymatic readout. A significant signal amplification was obtained by using streptavidin linked to alkaline phosphatase that binds to the remaining biotinylated detection probes and catalyzes the hydrolysis of the synthetic enzyme substrate α-naphthylphosphate. This dual amplification strategy tremendously increases the detection limit of the aptasensor. Under optimal conditions and using differential pulse voltammetry, cocaine can be detected in the concentration range between 2 and 500 nM with a detection limit as low as 1.3 nM (at S/N = 3). The method is specific and acceptably reproducible. It was successfully applied to the detection of cocaine in (spiked) urine samples. The data were in good agreement with those obtained by the GC-MS reference method. (author)

  11. Enzyme-Like Catalysis of the Nazarov Cyclization by Supramolecular Encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Courtney; Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2010-03-29

    A primary goal in the design and synthesis of molecular hosts has been the selective recognition and binding of a variety of guests using non-covalent interactions. Supramolecular catalysis, which is the application of such hosts towards catalysis, has much in common with many enzymatic reactions, chiefly the use of both spatially appropriate binding pockets and precisely oriented functional groups to recognize and activate specific substrate molecules. Although there are now many examples which demonstrate how selective encapsulation in a host cavity can enhance the reactivity of a bound guest, all have failed to reach the degree of increased reactivity typical of enzymes. We now report the catalysis of the Nazarov cyclization by a self-assembled coordination cage, a carbon-carbon bond-forming reaction which proceeds under mild, aqueous conditions. The acceleration in this system is over a million-fold, and represents the first example of supramolecular catalysis that achieves the level of rate enhancement comparable to that observed in several enzymes. We explain the unprecedented degree of rate increase as due to the combination of (a) preorganization of the encapsulated substrate molecule, (b) stabilization of the transition state of the cyclization by constrictive binding, and (c) increase in the basicity of the complexed alcohol functionality.

  12. Construction of single-crystalline supramolecular networks of perchlorinated hexa-peri-hexabenzocoronene on Au(111).

    Science.gov (United States)

    Zhang, Yi; Zhang, Yanfang; Li, Geng; Lu, Jianchen; Lin, Xiao; Tan, Yuanzhi; Feng, Xinliang; Du, Shixuan; Müllen, Klaus; Gao, Hong-Jun

    2015-03-14

    The self-assembly of the perchlorinated hexa-peri-hexabenzocoronene (PCHBC) molecules on Au(111) has been studied by a low temperature scanning tunneling microscopy (STM) combining with density functional theory based first principle calculations. Highly ordered supramolecular networks with single domains limited by the terraces are formed on Au(111) substrate. High resolution images of the PCHBC molecules, confirmed by first principle simulations, are obtained. It reveals the close-packed arrangement of the PCHBC molecules on Au(111). The calculated charge distribution of PCHBC molecules shows the existence of attractive halogen-halogen interaction between neighboring molecules. Compared with the disordered adsorption of hexa-peri-hexabenzocoronene on Au(111), we conclude that the formation of attractive Cl∙∙∙Cl interactions between neighbors is the key factor to form the highly ordered, close-packed networks. Due to the steric hindrance resulted from the peripheral chlorine atoms, the PCHBC molecule is contorted and forms the doubly concave conformation, which is different from the hexa-peri-hexabenzocoronene with a planar structure. By using this supramolecular network as a template, we deposited C60 molecules on it at room temperature with low coverage. The STM images taken at low temperature show that the C60 molecules are mono-dispersed on the networks and adsorb on top of the PCHBC molecules, forming a typical concave-convex host-guest system. PMID:25770500

  13. A Porous 3D Supramolecular Architecture of Cd(Ⅱ) Complex with Water Clusters as Pillars

    Institute of Scientific and Technical Information of China (English)

    YIN Pei-Xiu; LI Zhao-Ji; QIN Ye-Yan; CHENG Jian-Kai; ZHANG Lei; YAO Yuan-Gen

    2008-01-01

    A supramolecular complex of Cd(Ⅱ) with 1D water tapes as pillars[Cd2(dpa)2(phen)2- (H2O)2]·6H2O 1 (H2dpa = diphenic acid, phen = phenanthroline), has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group Pī with a = 9.7029(4), b = 11.9601(5), c = 12.1788(4) A, a = 71.6990(10), β = 71.8740(10), γ = 74.4680(10)°, V = 1252.39(8) A3 C52H48Cd2N4O16, Mr = 1209.76, Z = 1, Dc = 1.604 g/cm3,μ = 0.925 mm-1, F(000) = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections (Ⅰ > 2σ(Ⅰ)). Two intramolecular Cd(Ⅱ) centers of this complex are encircled by two dpa2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional (3D) supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.

  14. Construction of single-crystalline supramolecular networks of perchlorinated hexa-peri-hexabenzocoronene on Au(111)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yi; Zhang, Yanfang; Li, Geng; Lu, Jianchen; Du, Shixuan, E-mail: sxdu@iphy.ac.cn, E-mail: hjgao@iphy.ac.cn; Gao, Hong-Jun, E-mail: sxdu@iphy.ac.cn, E-mail: hjgao@iphy.ac.cn [Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190 (China); Lin, Xiao [University of Chinese Academy of Sciences and Institute of Physics, Chinese Academy of Sciences, Beijing 100049 (China); Tan, Yuanzhi [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany); Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Feng, Xinliang [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany); School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Müllen, Klaus [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany)

    2015-03-14

    The self-assembly of the perchlorinated hexa-peri-hexabenzocoronene (PCHBC) molecules on Au(111) has been studied by a low temperature scanning tunneling microscopy (STM) combining with density functional theory based first principle calculations. Highly ordered supramolecular networks with single domains limited by the terraces are formed on Au(111) substrate. High resolution images of the PCHBC molecules, confirmed by first principle simulations, are obtained. It reveals the close-packed arrangement of the PCHBC molecules on Au(111). The calculated charge distribution of PCHBC molecules shows the existence of attractive halogen–halogen interaction between neighboring molecules. Compared with the disordered adsorption of hexa-peri-hexabenzocoronene on Au(111), we conclude that the formation of attractive ClCl interactions between neighbors is the key factor to form the highly ordered, close-packed networks. Due to the steric hindrance resulted from the peripheral chlorine atoms, the PCHBC molecule is contorted and forms the doubly concave conformation, which is different from the hexa-peri-hexabenzocoronene with a planar structure. By using this supramolecular network as a template, we deposited C{sub 60} molecules on it at room temperature with low coverage. The STM images taken at low temperature show that the C{sub 60} molecules are mono-dispersed on the networks and adsorb on top of the PCHBC molecules, forming a typical concave-convex host-guest system.

  15. Syntheses of fluorescent thiocyanate supramolecular compounds with unusual two-dimensional structures

    Science.gov (United States)

    Bie, Hai-Ying; Lu, Jing; Yu, Jie-Hui; Xu, Ji-Qing; Zhao, Kui; Zhang, Xiao

    2005-05-01

    Three novel thiocyanate supramolecular compounds have been synthesized and characterized by X-ray diffraction and fluorescent spectra. Compound [pipH] 2[Co(NCS) 4] (pip=piperazine) 1 possesses a two-dimensional layer connected by the combination of N-H⋯N hydrogen bonds and weak S⋯S contacts. Under the same conditions, using nickel salt instead of cobalt salt as a starting material, we obtained a different two-dimensional supramolecular layer [pipH] 2[Ni(NCS) 4] 2 connected by unusual N-H⋯S hydrogen bonds and weak S⋯S contacts. In order to observe the influence of the dimension of ligand on the self-assembly structure, dabco was used for substituting pip, and compound [dabcoH] 2[Ni(NCS) 4] (dabco=1,4-Diazabicyclo[2.2.2] octane) 3 was gained, which constructed two-dimensional, highly wavy network with hourglass-shaped cavities only through N-H⋯S hydrogen bonds.

  16. Strong and Robust Polyaniline-Based Supramolecular Hydrogels for Flexible Supercapacitors.

    Science.gov (United States)

    Li, Wanwan; Gao, Fengxian; Wang, Xiaoqian; Zhang, Ning; Ma, Mingming

    2016-08-01

    We report a supramolecular strategy to prepare conductive hydrogels with outstanding mechanical and electrochemical properties, which are utilized for flexible solid-state supercapacitors (SCs) with high performance. The supramolecular assembly of polyaniline and polyvinyl alcohol through dynamic boronate bond yields the polyaniline-polyvinyl alcohol hydrogel (PPH), which shows remarkable tensile strength (5.3 MPa) and electrochemical capacitance (928 F g(-1) ). The flexible solid-state supercapacitor based on PPH provides a large capacitance (306 mF cm(-2) and 153 F g(-1) ) and a high energy density of 13.6 Wh kg(-1) , superior to other flexible supercapacitors. The robustness of the PPH-based supercapacitor is demonstrated by the 100 % capacitance retention after 1000 mechanical folding cycles, and the 90 % capacitance retention after 1000 galvanostatic charge-discharge cycles. The high activity and robustness enable the PPH-based supercapacitor as a promising power device for flexible electronics. PMID:27328742

  17. 典型超分子体系在放射化学领域的应用%Applications of Typical Supramolecular Systems in the Field of Radiochemistry

    Institute of Scientific and Technical Information of China (English)

    沈兴海; 张京晶; 高嵩; 付素珍; 孙涛祥; 付婧; 张红娟; 陈庆德; 高宏成

    2011-01-01

    本文主要通过评述两类超分子体系和离子印迹聚合物对重要金属离子的分离研究,阐明超分子化学在放射化学领域的重要应用。第一类超分子体系所含的主体分子有冠醚、杯芳烃、杯芳冠醚等大环化合物。第二类超分子体系主要有反胶束、微乳液和液膜。离子印迹聚合物通过超分子的识别功能实现对离子的选择性分离,而在液膜分离技术中,超分子的输运功能得到了很好的诠释。本文还对超分子化学在放射化学领域的应用前景作了分析展望。%Supramolecular chemistry is defined as "chemistry beyond the molecule",bearing on the organized entities of higher complexity that result from the association of two or more chemical species held together by intermolecular forces.Now,the applications of supramolecular chemistry in the realm of radiochemistry have attracted much attention.In this article,the separation of important metal ions by two kinds of supramolecular systems and ionic imprinted polymers(IIP) is discussed,which demonstrates the significant roles of supramolecular systems in the field of radiochemistry.Meanwhile,the first type is supermolecules resulted from the intermolecular association of a host molecule and its substrates,where the host molecules are mainly macrocyclic compounds(such as crown ethers,calixarene,calix crown ethers and so on).The second type is supramolecular assemblies induced by the spontaneous association of a large undefined number of components into a specific phase,including reversed micelles,microemulsions and liquid membranes.IIPs can recognize and separate metal ions selectively,which realizes the recognition function of supramolecular chemistry.The transport function of supramolecular chemistry is also well interpreted in the separation of metal ions by liquid membrane.Besides,the perspectives of supramolecular chemistry in the field of radiochemistry are also presented.

  18. Monitoring of antifungal drugs in biological samples using ultrasonic-assisted supramolecular dispersive liquid-liquid microextraction based on solidification of a floating organic droplet.

    Science.gov (United States)

    Ezoddin, Maryam; Abdi, Khosrou

    2016-08-01

    A new method for the simultaneous determination of the three antifungal drugs using ultrasonic-assisted supramolecular dispersive liquid-liquid microextraction based on solidification of a floating organic droplet (UASMDLLME-SFO) was proposed. The supramolecular solvents produced from reversed micelles of 1-dodecanol (extraction solvent) in tetrahydrofuran (THF) were injected into the aqueous sample solution. Reverse micelle coacervates were produced in situ through self-assembly processes. The antifungal drugs were extracted from the aqueous sample into a supramolecular solvent. Sonication accelerated the mass transfer of the target analytes into the supramolecular solvent phase and enhanced the dispersion process. Some parameters affecting the extraction efficiency such as type and volume of the extraction solvent, pH, volume of the disperser solvent and ultrasound extraction time were investigated. Under optimum conditions, the limits of detections for ketoconazole, clotrimazole and miconazole ranged from 0.08 to 1.3μgL(-1) and the relative standard deviations (RSDs, n=5)<6% were obtained. The method was successfully applied for preconcentration of the three drugs in biological and water samples. PMID:27262083

  19. Supramolecular complex formation of β-cyclodextrin polymer with substituted salicylic acid or 3-hydroxy-2-naphthoic acid and their electrorheological behaviors

    Institute of Scientific and Technical Information of China (English)

    GAO Ziwei; ZHAO Xiaopeng; SUN Ping; SI Gang

    2004-01-01

    According to the chemical design, electrorheological properties of supramolecular complex from β-cyclodextrin polymer (β -CDP) were discussed. Six supramolecular complexes of β-cyclodextrin polymer with substituted salicylic acid and 3-hydroxy-2-naphthoic acid were synthesized by the solid-phase self-assembly method, and their component and structure were characterized by NMR, FT-IR, UV-vis and the fluorescence analysis. Then the electrorheological properties of their suspensions in silicone oil were investigated under DC electric fields. It was found that the yield stresses of these supramolecular complex ER fluids were 7.3-9.8 kPa at 4kV/mm in DC electric field, which were enhanced by 34%-72% compared with that of pure β-CDP. Among them, that of β-CDP/3-hydroxy-2-naphthoic acid ER fluid was the highest. It was also found that the ER effect of supramolecular complexes can be controlled by changing different guests. When the substituted group is at phenyl ring, ER behavior can be slightly adjusted by the different substituted groups, their number as well as their position at phenyl ring. This can be proved by the measurement of dielectric properties.

  20. Self-assembly of metalloporphyrins: first TPP-bipy coordination polymer with CoII (TPP=meso-tetraphenylporphyrin and bipy=4,4´-bipyridine)

    OpenAIRE

    Fidalgo Marijuan, Arkaitz; Barandika Argoitia, Miren Gotzone; Bazán Blau, Begoña del Pilar; Urtiaga Greaves, Miren Karmele; Arriortua Marcaida, María Isabel

    2015-01-01

    Póster presentado en: 11th International Symposium on Applied Bioinorganic Chemistry. 2-5 Diciembre 2011. Barcelona, España (ISABC 2011) Supramolecular entities based on self-assembly of metalloporphyrins are paradigmatic examples of the great efficiency of the nanodevices used by natural systems in photosynthesis, oxygen transport, electron transfer and catalysis. Obtaining supramolecular entities may be approached by different strategies of synthetic design. One of them consists on t...

  1. Orthogonal Supramolecular Polymer Formation on Highly Oriented Pyrolytic Graphite (HOPG) Surfaces Characterized by Scanning Probe Microscopy.

    Science.gov (United States)

    Gong, Yongxiang; Zhang, Siqi; Geng, Yanfang; Niu, Chunmei; Yin, Shouchun; Zeng, Qingdao; Li, Min

    2015-10-27

    Formation of an orthogonal supramolecular polymer on a highly oriented pyrolytic graphite (HOPG) surface was demonstrated for the first time by means of scanning probe microscopy (SPM). Atomic force microscopy (AFM) was employed to characterize the variation of both the thickness and the topography of the film formed from (1) monomer 1, (2) monomer 1/Zn(2+), and (3) monomer 1/Zn(2+)/cross-linker 2, respectively. Scanning tunneling microscopy (STM) was used to monitor the self-assembly behavior of monomer 1 itself, as well as 1/Zn(2+) ions binary system on graphite surface, further testifying for the formation of linear polymer via coordination interaction at the single molecule level. These results, given by the strong surface characterization tool of SPM, confirm the formation of the orthogonal polymer on the surface of graphite, which has great significance in regard to fabricating a complex superstructure on surfaces.

  2. Building the Chessboard-like Supramolecular Structure on Au (111) Surfaces

    CERN Document Server

    Dou, Ruifen; Zhang, Ping; Zhong, Dingyong; Fuchs, Harald; Wang, Yue; Chi, Lifeng

    2013-01-01

    We investigate an anthracene derivative, 3(5)-(9-anthryl) pyrazole (ANP), self-assembled on the Au (111) surface by means of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. A chessboard-like network structure composed of ANP molecules is found, covering the whole Au (111) substrate. Our STM results and DFT calculations reveal that the formation of chessboard-like networks originates from a basic unit cell, a tetramer structure, which is formed by four ANP molecules connected through C-H-N hydrogen-bonds. The hydrogen bonds inside each tetramer and the molecular adsorption interaction are fundamentally important in providing a driving force for formation of the supramolecular networks.

  3. High intensity focused ultrasound responsive metallo-supramolecular block copolymer micelles.

    Science.gov (United States)

    Liang, Bo; Tong, Rui; Wang, Zhenhua; Guo, Shengwei; Xia, Hesheng

    2014-08-12

    The metal-supramolecular diblock copolymer containing mechano-labile bis(terpyridine)-Cu(II) complex linkage in the junction point was synthesized. These metal-ligand containing amphiphilic copolymers are able to self-assemble in aqueous solution to form spherical micelles with poly(propylene glycol) block forming the hydrophobic core. It is found that high intensity focused ultrasound can open the copolymer micelles and trigger the release of the payload in the micelle. The micellar properties and release kinetics of encapsulated guest molecule in response to ultrasound stimuli were investigated. The weak Cu(II)-terpyridine dynamic bond in the copolymer chain can be cleaved under ultrasound and thus leads to the disruption of the copolymer micelle and the release of loaded cargo. This study will open up a new way for the molecular design of ultrasound modulated drug delivery systems. PMID:25072274

  4. The role of van der Waals interactions in surface-supported supramolecular networks.

    Science.gov (United States)

    Nguyen, Manh-Thuong; Pignedoli, Carlo A; Treier, Matthias; Fasel, Roman; Passerone, Daniele

    2010-01-28

    The development of a detailed theoretical understanding of surface-supported supramolecular networks is important for designing novel organic nanodevices. By comparing with STM experiments, we show that van der Waals corrections to density functional theory (DFT) in the generalized gradient approximation (GGA) are mandatory to correctly reproduce the electronic and geometric structure of a prototypical system of this kind, the self-assembled hydrogen bonded network formed by 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) and 4,4''-diamino-p-terphenyl (DATP) deposited on Au(111). Our results reproduce both the network structure and its higher stability with respect to homomolecular networks. By successful comparison with the experiments, we demonstrate that dispersive interactions must be taken into account when rationally designing organic semiconductor nanostructures on a metallic substrate. DFT-GGA alone would fail in predicting geometric and electronic properties for weakly bounded large organic adsorbates on coinage metal surfaces. PMID:20066384

  5. Orthogonal Supramolecular Polymer Formation on Highly Oriented Pyrolytic Graphite (HOPG) Surfaces Characterized by Scanning Probe Microscopy.

    Science.gov (United States)

    Gong, Yongxiang; Zhang, Siqi; Geng, Yanfang; Niu, Chunmei; Yin, Shouchun; Zeng, Qingdao; Li, Min

    2015-10-27

    Formation of an orthogonal supramolecular polymer on a highly oriented pyrolytic graphite (HOPG) surface was demonstrated for the first time by means of scanning probe microscopy (SPM). Atomic force microscopy (AFM) was employed to characterize the variation of both the thickness and the topography of the film formed from (1) monomer 1, (2) monomer 1/Zn(2+), and (3) monomer 1/Zn(2+)/cross-linker 2, respectively. Scanning tunneling microscopy (STM) was used to monitor the self-assembly behavior of monomer 1 itself, as well as 1/Zn(2+) ions binary system on graphite surface, further testifying for the formation of linear polymer via coordination interaction at the single molecule level. These results, given by the strong surface characterization tool of SPM, confirm the formation of the orthogonal polymer on the surface of graphite, which has great significance in regard to fabricating a complex superstructure on surfaces. PMID:26457462

  6. Two-Dimensional Supramolecular Polymers Embodying Large Unilamellar Vesicles in Water.

    Science.gov (United States)

    Chen, Shigui; Polen, Shane M; Wang, Lu; Yamasaki, Makoto; Hadad, Christopher M; Badjić, Jovica D

    2016-09-01

    We hereby describe a strategy for obtaining novel topological nanostructures consisting of dual-cavity basket 1, forming a curved monolayer of large unilamellar vesicles in water (CAC < 0.25 μM), and bivalent guests 4/5 populating the cavities of such bolaamphiphilic hosts. On the basis of the results of (1)H NMR spectroscopy, electron microscopy, and dynamic light scattering measurements, we postulated that divalent guest molecules 4/5 cover the curved vesicular surface in a lateral fashion to satisfy the complexation [2 + 2] valency and thereby give stable two-dimensional supramolecular polymers [1⊂4]n and [1⊂5]n. The results of experimental studies are also supported with coarse-grained molecular dynamics simulations and molecular mechanics. Our discovery about the assembly of novel vesicular structures could be of interest for stabilization/functionalization of liposomal surfaces as well as detection of polyvalent molecules and removal of targeted substances from aqueous environments. PMID:27510921

  7. pH responsive Janus-like supramolecular fusion proteins for functional protein delivery.

    Science.gov (United States)

    Kuan, Seah Ling; Ng, David Y W; Wu, Yuzhou; Förtsch, Christina; Barth, Holger; Doroshenko, Mikheil; Koynov, Kaloian; Meier, Christoph; Weil, Tanja

    2013-11-20

    A facile, noncovalent solid-phase immobilization platform is described to assemble Janus-like supramolecular fusion proteins that are responsive to external stimuli. A chemically postmodified transporter protein, DHSA, is fused with (imino)biotinylated cargo proteins via an avidin adaptor with a high degree of spatial control. Notably, the derived heterofusion proteins are able to cross cellular membranes, dissociate at acidic pH due to the iminobiotin linker and preserve the enzymatic activity of the cargo proteins β-galactosidase and the enzymatic subunit of Clostridium botulinum C2 toxin. The mix-and-match strategy described herein opens unique opportunities to access macromolecular architectures of high structural definition and biological activity, thus complementing protein ligation and recombinant protein expression techniques. PMID:24156787

  8. Construction and Ion Exchange Properties of Supramolecular Complexes with Organic Ligands and Metal Ions

    Institute of Scientific and Technical Information of China (English)

    SUN; WeiYin

    2001-01-01

    Supramolecular architectures with specific topologies such as closed threedimensional molecular cages present a large range of applications in material science, medicine and chemical technology.1,2 In the past decades, a number of such frameworks, e.g. M6L4, M12L8 and M18L6, have been synthesized by assembly of organic ligands with transitional metal salts.3-5 However, the M3L2 type cage-like complexes are not well known up to now.6,7 We report herein the generation of M3L2 type cages by tripodal ligands and various metal salts, and the anion exchange, molecular recognition properties of these metallosupramolecular cages.  ……

  9. Construction and Ion Exchange Properties of Supramolecular Complexes with Organic Ligands and Metal Ions

    Institute of Scientific and Technical Information of China (English)

    SUN WeiYin; FAN Jian

    2001-01-01

    @@ Supramolecular architectures with specific topologies such as closed threedimensional molecular cages present a large range of applications in material science, medicine and chemical technology.1,2 In the past decades, a number of such frameworks, e.g. M6L4, M12L8 and M18L6, have been synthesized by assembly of organic ligands with transitional metal salts.3-5 However, the M3L2 type cage-like complexes are not well known up to now.6,7 We report herein the generation of M3L2 type cages by tripodal ligands and various metal salts, and the anion exchange, molecular recognition properties of these metallosupramolecular cages.

  10. Pattern formation in centrosome assembly.

    Science.gov (United States)

    Mahen, Robert; Venkitaraman, Ashok R

    2012-02-01

    A striking but poorly explained feature of cell division is the ability to assemble and maintain organelles not bounded by membranes, from freely diffusing components in the cytosol. This process is driven by information transfer across biological scales such that interactions at the molecular scale allow pattern formation at the scale of the organelle. One important example of such an organelle is the centrosome, which is the main microtubule organising centre in the cell. Centrosomes consist of two centrioles surrounded by a cloud of proteins termed the pericentriolar material (PCM). Profound structural and proteomic transitions occur in the centrosome during specific cell cycle stages, underlying events such as centrosome maturation during mitosis, in which the PCM increases in size and microtubule nucleating capacity. Here we use recent insights into the spatio-temporal behaviour of key regulators of centrosomal maturation, including Polo-like kinase 1, CDK5RAP2 and Aurora-A, to propose a model for the assembly and maintenance of the PCM through the mobility and local interactions of its constituent proteins. We argue that PCM structure emerges as a pattern from decentralised self-organisation through a reaction-diffusion mechanism, with or without an underlying template, rather than being assembled from a central structural template alone. Self-organisation of this kind may have broad implications for the maintenance of mitotic structures, which, like the centrosome, exist stably as supramolecular assemblies on the micron scale, based on molecular interactions at the nanometer scale. PMID:22245706

  11. Solvent-induced helical assembly and reversible chiroptical switching of chiral cyclic-dipeptide-functionalized naphthalenediimides.

    Science.gov (United States)

    Manchineella, Shivaprasad; Prathyusha, V; Priyakumar, U Deva; Govindaraju, T

    2013-12-01

    Understanding the roles of various parameters in orchestrating the preferential chiral molecular organization in supramolecular self-assembly processes is of great significance in designing novel molecular functional systems. Cyclic dipeptide (CDP) chiral auxiliary-functionalized naphthalenediimides (NCDPs 1-6) have been prepared and their chiral self-assembly properties have been investigated. Detailed photophysical and circular dichroism (CD) studies have unveiled the crucial role of the solvent in the chiral aggregation of these NCDPs. NCDPs 1-3 form supramolecular helical assemblies and exhibit remarkable chiroptical switching behaviour (M- to P-type) depending on the solvent composition of HFIP and DMSO. The strong influence of solvent composition on the supramolecular chirality of NCDPs has been further corroborated by concentration and solid-state thin-film CD studies. The chiroptical switching between supramolecular aggregates of opposite helicity (M and P) has been found to be reversible, and can be achieved through cycles of solvent removal and redissolution in solvent mixtures of specific composition. The control molecular systems (NCDPs 4-6), with an achiral or D-isomer second amino acid in the CDP auxiliary, did not show chiral aggregation properties. The substantial roles of hydrogen bonding and π-π interactions in the assembly of the NCDPs have been validated through nuclear magnetic resonance (NMR), photophysical, and computational studies. Quantum chemical calculations at the ab initio, semiempirical, and density functional theory levels have been performed on model systems to understand the stabilities of the right (P-) and left (M-) handed helical supramolecular assemblies and the nature of the intermolecular interactions. This study emphasizes the role of CDP chiral auxiliaries on the solvent-induced helical assembly and reversible chiroptical switching of naphthalenediimides. PMID:24281809

  12. Nanostructured assemblies from amphiphilic ABC multiblock polymers

    Science.gov (United States)

    Hillmyer, Marc A.

    2012-02-01

    Amphiphilic AB diblock copolymers containing a water compatible segment can self-assemble in aqueous media to give supramolecular structures that include simple spherical micelles and macromolecular vesicles termed polymersomes. Amphiphilic ABA triblocks with hydrophobic end blocks can adopt analogous structures but can also form gels at high polymer concentrations. The structural and chemical diversity demonstrated in block copolymer micelles and gels makes them attractive for applications ranging from drug delivery to personal care products to nanoreactors. The inclusion of a third block in amphiphilic ABC triblock systems can lead to a much wider array of self-assembled structures that depend not only on composition but also on block sequence, architecture and incompatibility considerations. I will present our recent efforts on tuning micelle and gel structure and behavior using controlled architecture ABC triblocks. The combination of diverse polymer segments into a single macromolecule is a powerful method for development of self-assembled structures with both new form and new function.

  13. Allelic dropout of amelogenin gene on X chromosome%X染色体Amelogenin等位基因缺失的研究

    Institute of Scientific and Technical Information of China (English)

    陈勇; 孙宏钰; 陈爱萍; 陈维红; 何树文

    2008-01-01

    目的 探讨采用Amelogenin基因常规Sullivan106/112 bp体系进行性别鉴定时X染色体Amelogenin等位基因片段(Amel-X)缺失的原因以及缺失后对法医物证性别鉴定和临床疾病诊断的影响.方法 采用Sullivan212/218 bp和Haas-Rochholz80/83 bp引物体系对Amel-X缺失的样本进行验证,并对缺失的Amel-X进行序列分析.结果 采用Sullivan212/218 bp和Haas-Rochholz80/83 bp引物体系分型时均可重获缺失的等位基因.测序分析在Sullivan106/112 bp体系的正向引物结合区检出3种点突变,包括分别位于3'端第2位、第13位的单点突变以及第2位和第13位同时发生的杂合多点突变.结论 引物结合区点突变导致的无效扩增是Amel-X等位基因缺失的原因,这在实践中会干扰性别鉴定,需引起重视.%Objective To investigate the mechanism that cause allelic dropout of amelogenin gene on X chromosome(Amel-X)when using routine Sullivan106/112 bp primer set in sex identification and discuss its influence on the forensic sex identification and the clinical diagnosis.Methods Amel-X dropout was validated with Sullivan212/218 bp and Haas-Rochholz80/83 bp primer sets.Amplification of amelogenin gene was used to analyze dropout of the Amex-X followed by sequencin.Results Sullivan212/218 bp and Hgas-Rochholz80/83 bp primer sets could be used to identify gender correctly.Three types of point mntation were observed in the forward primer binding region of the Sullivan106/112 bp primer set by sequencing in the lost Amel-X,including single point mutation at 2nd and 13th sites,respectively,and heterozygous multiple point mutations at 2nd and 13th sites.Conclusions Point mutation in the primer binding region may result in a failure to amplify amelogenin allele and thus lead to a null allele.This finding should be mid attention to because it may interfere with the sex identification.

  14. Self-assemblies of lecithin and a-tocopherol as gelators of lipid material

    NARCIS (Netherlands)

    Nikiforidis, C.V.; Scholten, E.

    2014-01-01

    Amongst the different mechanisms that have been proposed and used to structure organogels, self-assembly of the gelators into supramolecular structures linked through non-covalent bonds is the most interesting. The gelator activity of LMGOs is often found most effective when micellar or lamellar pha

  15. Self-assembled M2L4 coordination cages : Synthesis and potential applications

    NARCIS (Netherlands)

    Schmidt, Andrea; Casini, Angela; Kuehn, Fritz E.

    2014-01-01

    Metal-mediated self-assemblies of the general formula MxLy (M = metal ion, L = ligand) have emerged as a promising research area of supramolecular chemistry because of their applicability in various fields such as molecular recognition, catalysis and drug delivery. The focus of this review is on dis

  16. Assembled diglycolamide for f-element ions sequestration at high acidity

    NARCIS (Netherlands)

    Chavan, V.; Thekkethil, V.; Pandey, A.K.; Iqbal, M.; Huskens, J.; Singh Meena, S.; Goswami, A.; Verboom, W.

    2014-01-01

    Diglycolamides (DGA) form reverse-micellar type of supramolecular aggregates upon equilibration with a nitric acid solution that enhances DGA affinity extraordinary towards f-elements. To mimic DGA aggregates, DGA molecules have been preorganized on chemical platforms to form assemblies having a goo

  17. Encapsulation of Metalloporphyrins in a Self-Assembled Cubic M8L6 Cage: A New Molecular Flask for Cobalt-Porphyrin-Catalysed Radical-Type Reactions

    NARCIS (Netherlands)

    M. Otte; P.F. Kuijpers; O. Troeppner; I. Ivanović-Burmazović; J.N.H. Reek; B. de Bruin

    2013-01-01

    The synthesis of a new, cubic M8L6 cage is described. This new assembly was characterised by using NMR spectroscopy, DOSY, TGA, MS, and molecular modelling techniques. Interestingly, the enlarged cavity size of this new supramolecular assembly allows the selective encapsulation of tetra(4-pyridyl)me

  18. Selection of conformational states in self-assembled surface structures formed from an oligo(naphthylene-ethynylene) 3-bit binary switch

    DEFF Research Database (Denmark)

    Ning, Yanxiao; Cramer, Jacob Roland; Nuermaimaiti, Ajiguli;

    2015-01-01

    Supra-molecular self-assembly on surfaces often involves molecular conformational flexibility which may act to enrich the variation and complexity of the structures formed. However, systematic and explicit investigations of how molecular conformational states are selected in surface self-assembly...

  19. Towards simultaneous individual and tissue identification: A proof-of-principle study on parallel sequencing of STRs, amelogenin, and mRNAs with the Ion Torrent PGM.

    Science.gov (United States)

    Zubakov, D; Kokmeijer, I; Ralf, A; Rajagopalan, N; Calandro, L; Wootton, S; Langit, R; Chang, C; Lagace, R; Kayser, M

    2015-07-01

    DNA-based individual identification and RNA-based tissue identification represent two commonly-used tools in forensic investigation, aiming to identify crime scene sample donors and helping to provide links between DNA-identified sample donors and criminal acts. Currently however, both analyses are typically performed separately. In this proof-of-principle study, we developed an approach for the simultaneous analysis of forensic STRs, amelogenin, and forensic mRNAs based on parallel targeted DNA/RNA sequencing using the Ion Torrent Personal Genome Machine(®) (PGM™) System coupled with the AmpliSeq™ targeted amplification. We demonstrated that 9 autosomal STRs commonly used for individual identification (CSF1PO, D16S539, D3S1358, D5S818, D7S820, D8S1179, TH01, TPOX, and vWA), the AMELX/AMELY system widely applied for sex identification, and 12 mRNA markers previously established for forensic tissue identification (ALAS2 and SPTB for peripheral blood, MMP10 and MMP11 for menstrual blood, HTN3 and STATH for saliva, PRM1 and TGM4 for semen, CYP2B7P1 and MUC4 for vaginal secretion, CCL27 and LCE1C for skin) together with two candidate reference mRNA markers (HPRT1 and SDHA) can all be successfully combined. Unambiguous mRNA-based tissue identification was achieved in all samples from all forensically relevant tissues tested, and STR sequencing analysis of the tissue sample donors was 100% concordant with conventional STR profiling using a commercial kit. Successful STR analysis was obtained from 1ng of genomic DNA and mRNA analysis from 10ng total RNA; however, sensitivity limits were not investigated in this proof-of-principle study and are expected to be much lower. Since dried materials with noticeable RNA degradation and small DNA/RNA amplicons with high-coverage sequencing were used, the achieved correct individual and tissue identification demonstrates the suitability of this approach for analyzing degraded materials in future forensic applications. Overall

  20. Towards simultaneous individual and tissue identification: A proof-of-principle study on parallel sequencing of STRs, amelogenin, and mRNAs with the Ion Torrent PGM.

    Science.gov (United States)

    Zubakov, D; Kokmeijer, I; Ralf, A; Rajagopalan, N; Calandro, L; Wootton, S; Langit, R; Chang, C; Lagace, R; Kayser, M

    2015-07-01

    DNA-based individual identification and RNA-based tissue identification represent two commonly-used tools in forensic investigation, aiming to identify crime scene sample donors and helping to provide links between DNA-identified sample donors and criminal acts. Currently however, both analyses are typically performed separately. In this proof-of-principle study, we developed an approach for the simultaneous analysis of forensic STRs, amelogenin, and forensic mRNAs based on parallel targeted DNA/RNA sequencing using the Ion Torrent Personal Genome Machine(®) (PGM™) System coupled with the AmpliSeq™ targeted amplification. We demonstrated that 9 autosomal STRs commonly used for individual identification (CSF1PO, D16S539, D3S1358, D5S818, D7S820, D8S1179, TH01, TPOX, and vWA), the AMELX/AMELY system widely applied for sex identification, and 12 mRNA markers previously established for forensic tissue identification (ALAS2 and SPTB for peripheral blood, MMP10 and MMP11 for menstrual blood, HTN3 and STATH for saliva, PRM1 and TGM4 for semen, CYP2B7P1 and MUC4 for vaginal secretion, CCL27 and LCE1C for skin) together with two candidate reference mRNA markers (HPRT1 and SDHA) can all be successfully combined. Unambiguous mRNA-based tissue identification was achieved in all samples from all forensically relevant tissues tested, and STR sequencing analysis of the tissue sample donors was 100% concordant with conventional STR profiling using a commercial kit. Successful STR analysis was obtained from 1ng of genomic DNA and mRNA analysis from 10ng total RNA; however, sensitivity limits were not investigated in this proof-of-principle study and are expected to be much lower. Since dried materials with noticeable RNA degradation and small DNA/RNA amplicons with high-coverage sequencing were used, the achieved correct individual and tissue identification demonstrates the suitability of this approach for analyzing degraded materials in future forensic applications. Overall